Thursday, September 15, 2011

EPITHELIUM

EPITHELIAL TISSUE

Despite its complexity, the human body is composed of only four basic types of tissue: EPITHELIAL, CONNECTIVE, MUSCULAR, and NERVOUS. These tissues, which are formed by cells and molecules of the extracellular matrix, exist not as isolated units but rather in association with one another and in variable proportions, forming different organs and systems of the body. Also of great functional importance are the FREE CELLS found in body fluids such as blood and lymph.


Most organs can be divided into two components: parenchyma, which is composed of the cells responsible for the main functions typical of the organ, and stroma (mesenchyma), which is the supporting tissue.

FUNCTIONS:

The principal functions of epithelial (Gr. epi, upon, + thele, nipple) tissues are the covering and lining of surfaces (eg, skin, intestines), absorption (eg, intestines), secretion (eg, glands), sensation (eg, gustative and olfactory neuroepithelium), and contractility (eg, myoepithelial cells). Because epithelial cells line all external and internal surfaces of the body, everything that enters or leaves the body must cross an epithelial sheet.

THE FORMS & CHARACTERISTICS OF EPITHELIAL CELLS:

The forms and dimensions of epithelial cells range from high columnar to cuboidal to low squamous cells.


Epithelial cell nuclei have distinctive shapes, varying from spherical to elongated or elliptic. The form of the nuclei of epithelial cells corresponds roughly to the cell shape; thus, cuboidal cells have spherical nuclei and squamous cells have flattened nuclei. The long axis of the nucleus is always parallel to the main axis of the cell.

Almost all epithelial cells, whether lining a surface or forming gland units, rest on a connective tissue. In the case of epithelia that line the cavity of internal organs (especially the digestive, respiratory, and urinary systems) this layer of connective tissue is often called lamina propria. The lamina propria not only serves to support the epithelium but also provides nutrition and binds it .

The portion of the epithelial cells that faces the connective tissue is called the basal pole, whereas the opposite side, usually facing a space, is called the apical pole. The surface of the apical pole is also called the free surface, whereas the surfaces that are apposed to neighbor cells are called lateral surfaces.

Basal Lamina & Basement Membrane

Most epithelial cells are separated from the connective tissue by a sheet of extracellular material called the basal lamina. This structure is visible only with the electron microscope, where it appears as a dense layer, 20–100 nm thick, consisting of a delicate network of very fine fibrils (lamina densa) .In addition, basal laminae may have an electron-lucent layer on one or both sides of the lamina densa, called lamina rara or lamina lucida. Between cell layers without intervening connective tissue, such as in lung alveoli and in the renal glomerulus ,the basal lamina is thicker as a result of fusion of the basal laminae of each epithelial cell layer.



The main components of basal laminae are type IV collagen, the glycoproteins laminin and entactin, and proteoglycans (eg, the heparan sulfate proteoglycan called perlecan). In some instances, reticular fibers are closely associated with the basal lamina, forming the reticular lamina. The term basement membrane is used to specify a periodic acid–Schiff (PAS)-positive layer, visible with the light microscope, present beneath some epithelia.


Intercellular Adhesion & Intercellular Junctions

Several membrane-associated structures contribute to cohesion and communication between cells. They are present in most tissues but are ,prominent in epithelium. Adhesion is due in part to the binding action of a family of transmembrane glycoproteins called cadherins.




Tight junctions, or zonulae occludens (singular, zonula occludens), are the most apical of the junctions. The Latin terminology gives important information about the geometry of the junction. "Zonula" refers to the fact that the junction forms a band completely encircling the cell , and "occludens" refers to the membrane fusions that close off the intercellular space.

In many epithelia, the next type of junction encountered is the zonula adherens. This junction encircles the cell and provides for the adhesion of one cell to its neighbor. A noteworthy feature of this junction is the insertion of numerous actin filaments into electron-dense plaques of material on the cytoplasmic surfaces of the junctional membranes. The filaments belong to the terminal web, a web of actin filaments, intermediate filaments, and spectrin found close to the free surface.

Gap or communicating junctions can occur almost anywhere along the lateral membranes of epithelial cells. The individual unit of the gap junction is called a connexon. Each connexon is formed by six gap junction proteins called connexins, which join together leaving a hydrophilic pore about 1.5 nm in diameter in the center. Connexons of adjacent cells are aligned to form a hydrophilic channel between the two cells . Each gap junction is formed by tens or hundreds of aligned pairs of connexons. A typical example is heart muscle cells, where gap junctions are, to a great degree, responsible for the heart's coordinated beat.

The final type of junction is the DESMOSOME (Gr. desmos, band, + soma, body), or MACULA ADHERENS. The desmosome is a complex disk-shaped structure at the surface of one cell that is matched with an identical structure at the surface of the adjacent cell. The cell membranes in this region are very straight and are frequently somewhat farther apart (>30 nm) than the usual 20 nm. On the cytosolic side of the membrane of each cell and separated from it by a short distance is a circular plaque of material called an ATTACHMENT PLAQUE, made up of at least 12 different proteins. In epithelial cells, groups of INTERMEDIATE CYTOKERATIN FILAMENTS are inserted into the attachment plaque or make hairpin turns and return to the cytoplasm. Because intermediate filaments of the cytoskeleton are very strong, desmosomes provide a firm adhesion among the cells. In nonepithelial cells, the intermediate filaments attached to desmosomes are made not of cytokeratin but of other proteins, such as desmin or vimentin. Proteins of the cadherin family participate in the adhesion provided by desmosomes







Specializations of the Cell Surface

Microvilli

When viewed in the electron microscope, the majority of cells from several different tissues are seen to have cytoplasmic projections. These projections, the microvilli (Gr. mikros, small, + L. villus, tuft of hair), are fingerlike extensions measuring about 1 m high and 0.08 m wide. They are found mainly on the free cell surface. Hundreds of microvilli are found in absorptive cells, such as the lining epithelium of the small intestine and the cells of the proximal renal tubule In these absorptive cells the glycocalyx is thicker than it is in most other cells. The complex of microvilli and glycocalyx may be seen with the light microscope and is called the brush, or striated, border.


As seen at higher magnification in micrograph, the cytoplasmic core of each microvillus contains actin microfilaments F which insert into the terminal web, a specialisation of the actin cytoskeleton lying immediately beneath the cell surface. At the periphery of the cell the terminal web is anchored to the zonula adherens .At the tip of the microvillus, the filaments attach to an electron-dense part of the plasma membrane. The microfilaments maintain stability of microvilli and may also mediate some contraction and elongation of the microvilli.



STEREOCILIA

Stereocilia are long, nonmotile extensions of cells of the epididymis and ductus deferens that are actually long and branched microvilli and should not be confused with true cilia. Stereocilia increase the cell surface area, facilitating the movement of molecules into and out of the cell.


CILIA & FLAGELLA

Cilia are cylindrical, motile structures on the surface of some epithelial cells, 5–10 m long and 0.2 m in diameter. They are surrounded by the cell membrane and contain a central pair of isolated microtubules surrounded by nine pairs of microtubules. The two microtubules of the peripheral pairs are joined to each other.


Cilia are inserted into BASAL BODIES, which are small cylindrical structures at the apical pole just below the cell membrane .Basal bodies have a structure analogous to that of the centrioles.
In living organisms, cilia have a rapid back-and-forth movement. Ciliary movement is frequently coordinated to permit a current of fluid or particulate matter to be propelled in one direction over the epithelial surface. Adenosine triphosphate (ATP) is the source of energy for ciliary motion. A ciliated cell of the TRACHEA is estimated to have about 250 cilia.
Flagella, present in the human body ONLY IN SPERMATOZOA, are similar in structure to cilia but are much longer and are limited to one flagellum per cell.










ALL BLOOD VESSELS ARE LINED WITH A SIMPLE SQUAMOUS EPITHELIUM CALLED ENDOTHELIUM


THE SIMPLE SQUAMOUS EPITHELIUM THAT COVERS THE BODY CAVITIES (THE ABDOMINAL CAVITY IN THIS CASE) IS CALLED MESOTHELIUM. PT STAIN. MEDIUM MAGNIFICATION


SIMPLE CUBOIDAL EPITHELIUM (ARROW) FROM KIDNEY COLLECTING TUBULES. PT STAIN. LOW MAGNIFICATION



SIMPLE COLUMNAR EPITHELIUM FORMED BY LONG CELLS WITH ELLIPTICAL NUCLEI.


STRATIFIED SQUAMOUS NONKERATINIZED (MOIST) EPITHELIUM OF THE ESOPHAGUS. THE MOST SUPERFICIAL CELLS (ARROW) HAVE THE FORM OF VERY THIN SCALES. PT STAIN. MEDIUM MAGNIFICATION.


STRATIFIED TRANSITIONAL EPITHELIUM OF THE URETHRA. THE RED-STAINED BASEMENT MEMBRANE BETWEEN THE EPITHELIUM AND THE UNDERLYING LOOSE CONNECTIVE TISSUE IS INDICATED BY ARROWS.


PSEUDOSTRATIFIED COLUMNAR EPITHELIUM OF THE TRACHEA, FORMED BY LONG AND SHORT CELLS. AS SOME CELLS DO NOT REACH THE SURFACE OF THE EPITHELIUM THEIR NUCLEI ARE PRESENT IN DIFFERENT HEIGHTS OF THE EPITHELIAL LAYER. MUCUS-SECRETING CELLS, CALLED GOBLET CELLS (ARROW), INTERMINGLE WITH CILIATED LINING CELLS.

GLANDULAR EPITHELIA
  • Glandular epithelia are formed by cells specialized to produce secretion. The molecules to be secreted are generally stored in the cells in small membrane-bound vesicles called secretary granules.
  • Glandular epithelial cells may synthesize, store, and secrete proteins (eg, pancreas), lipids (e.g., adrenal, sebaceous glands)
  • complexes of carbohydrates and proteins (eg, salivary glands).
  • The mammary glands secrete all three substances.

TYPES OF GLANDULAR EPITHELIA

The epithelia that form the glands of the body can be classified according to various criteria. Unicellular glands consist of isolated glandular cells, and multicellular glands are composed of clusters of cells. An example of a unicellular gland is the GOBLET CELL of the lining of the small intestine, or of the respiratory tract. The term "gland," however, is usually used to designate large, complex aggregates of glandular epithelial cells, such as in the salivary glands and the pancreas.


Section of large intestine showing goblet cells (arrows) secreting mucus to the extracellular space. The mucus precursor stored in the cytoplasm of the goblet cells is also stained in a dark color.

The nucleus of the goblet cell on the right is outside the plane of section, the nucleus N of the other being typically highly condensed showing a goblet cell in horizontal section). The cytoplasm is packed with rough endoplasmic reticulum rER; a few mitochondria M are present. A prominent Golgi apparatus G is found in the supranuclear region although it is barely visible at this magnification.

The protein component of mucigen is synthesised by the rough endoplasmic reticulum and passed to the Golgi apparatus where it is combined with carbohydrate and packaged into membrane-bound, secretory granules containing mucigen Mu


Formation of glands from covering epithelia. Epithelial cells proliferate and penetrate the connective tissue.


Simple tubular glands, LARGE INTESTINE

Simple coiled tubular glands,
Sweat glands are almost the only example of simple coiled tubular glands.


Simple branched tubular glands
mainly in the stomach.


In this example of the mucus-secreting glands of the penile urethra, the secretory cells are pale stained compared to the non-secretory cells lining the urethra U. Note that the term acinus can be used to describe any rounded exocrine secretory unit.


Sebaceous glands provide a good example of simple branched acinar glands. Each gland consists of several secretory acini A that empty into a single excretory duct; the excretory duct E is formed by the stratified epithelium surrounding the hair shaft. The mode of secretion of sebaceous glands is HOLOCRINE, i.e. the secretory product, sebum, accumulates within the secretory cells and is discharged by degeneration of the cells.


Brunner's glands of the duodenum, as shown in this example, are described as compound branched tubular glands. Although difficult to visualise here, the duct system D is branched, thus defining the glands as compound glands and the secretory portions S have a tubular form, which is branched and coiled.


Compound acinar glands are those in which the secretory units are acinar in form and drain into a branched excretory ducts E system. The pancreas .



Compound tubulo-acinar glands have three types of secretory units; namely BRANCHED TUBULAR, BRANCHED ACINAR and branched tubular with acinar end-pieces called DEMILUNES. THE SUBMANDIBULAR SALIVARY GLAND shown here is the classic example. It contains two types of secretory cells, mucus-secreting cells and serous cells; the former are pale but the latter, which have a protein-rich secretion (digestive enzymes), stain strongly due to their large content of rough endoplasmic reticulum. Generally, the mucous cells form tubular components T whereas the serous cells form acinar components A and demilunes D. Part of an excretory duct E is also seen in the lower left corner of the micrograph.

Based on how the secretory products leave the cell, glands can be classified as merocrine (Gr. meros, part, + krinein) or holocrine (Gr. holos, whole, + krinein). In merocrine glands (eg, the pancreas), the secretory granules leave the cell by exocytosis with no loss of other cellular material. In holocrine glands (eg, sebaceous glands), the product of secretion is shed with the whole cell—a process that involves destruction of the secretion-filled cells. In an intermediate type—the apocrine (Gr. apo, away from, + krinein) gland—the secretory product is discharged together with parts of the apical cytoplasm,mammary gland

General Biology of Epithelial Tissues

POLARITY

In many types of epithelial cells the distribution of organelles and membrane proteins is different when comparing the basal and apical poles of the cell. This differential and stable organization of cell components is called polarity. This means that different parts of the cell may have different functions.

INNERVATION

Most epithelial tissues receive a rich supply of sensory nerve endings from nerve plexuses in the lamina propria. The exquisite sensitivity of the cornea, the epithelium covering the anterior surface of the eye, is due to the great number of sensory nerve fibers that ramify between corneal epithelial cells.

RENEWAL OF EPITHELIAL CELLS

Epithelial tissues are labile and their cells are renewed continuously by means of mitotic activity. The renewal rate is variable; it can be fast in tissues such as the intestinal epithelium, in which cells are replaced every week, or slow, as in the liver and the pancreas. In stratified and pseudostratified epithelial tissues, mitosis takes place within the germinal layer, closest to the basal lamina, which contains the stem cells.

Sunday, September 11, 2011

VIRGINITY, PREGNANCY, DELIVERY AND LEGITIMACY

Definitions:

Virginity: a virgin is a woman who has never had any sexual intercourse.
Defloration: loss of virginity

SIGNS OF VIRGINITY
  • Breasts: hemispherical, firm and rounded.
  • Nipple: small, undeveloped, areola is pink.
  • Labia majora: firm, elastic, rounded & completely.
  • Labia minora: soft, smooth, small, sensitive & pink in color.
  • Fourchette & posterior commisure: intact.
  • Vaginal wall: closely approximated.
  • Vaginal mucosa: rugose, reddish, sensitive to touch.
  • Hymen: intact, deeply situated in children & superficial after puberty, soft to firm in consistency & usually annular or semilunar in shape.



Different types or shapes of hymen:

  • Annular or circular (with a central aperture)
  • Cresentic or semi lunar
  • Fimbriated or notched
  • Septate (divided into two openings by a septum)
  • Cribiform (with several openings)
  • imperforate

Difference between fimbriate & torn hymen

Fimbriate

  • Notches are symmetrical
  • Notches occur anteriorly
  • Do not extend to vaginal wall
  • Mucus membrane intact
  • No signs of inflammation

Torn Hymen

  • Irregular
  • Usually posteriorly
  • Extend to vaginal wall
  • Damaged
  • Signs of inflammation present

Signs of defloration:
  • Carunculae myrtiformes: several small, granular tags or knobs of tissues (remnants of hymen).
  • Labia majora & vagina: lose of tone and rugosity.
  • Labia minora: leathery and hard.


Conditions causing ruptured hymen before coitus
  • Accidents
  • Masturbation
  • Instrumentation by doctors
  • Artificial dilatation of vagina by foreign bodies for prostitution
  • Passage of large blood clots

True virgin

  • Hymen is intact & the woman has had no sexual intercourse.
  • It only admits tip of little finger in vagina.

False virgin

  • Hymen is intact but the woman has had sexual intercourse
  • It can easily admit two fingers in vagina.

MLI of Virginity
  • Divorce
  • Defamation (chastity)
  • Rape

Signs of prgenancy in living:

Subjective

  • Cessation of menstruation
  • Morning sickness
  • Sympathetic disturbances (salivation, altered taste, irritable temper)
  • Quickening (movement of fetus felt by mother) – after 14-18 weeks
  • Frequency of micturation

Objective

  • Breast changes
  • Skin changes
  • Vaginal changes
  • Changes in cervix
  • Hegar’s sign (softening & compressibility of lower uterine segment from 2nd to 5th month)
  • Progressive enlargement of abdomen
  • Braxton Hick’s sign: intermittent contraction & relaxation of uterus after 4th month
  • Uterine souffle (soft blowing murmur heard by 3rd or 4th month)
  • Ballottment

Breast changes:

  • 2nd month: breast becomes full & tender, increase in size, veins become prominent, nipples enlarged, areola wider & darker, Montgomery’s tubercles (ENLARGED SEBACEOUS GLANDS)appear.
  • 3rd month: colostrum can be squeezed out of the nipples.
  • 6th month: lines like linea albicantes appear on breast due to stretching.


Skin changes:
  • Pigmentation of abdomen, axillae, pubis & vulva.
  • A dark line extends from symphysis to umbilicus called linea nigra.

Vaginal changes:
  • Pressure of the gravid uterus >> increased vascularity >> mucosa becomes purple or bluish purple >> Jacqueimier’s sign.
  • 4th month- pulsation of vaginal arteries is felt by placing a finger in vagina (osiander sign)

Changes in cervix:
  • 4th month- cervix becomes soft like lips (goodell’s sign)

Location of uterine fundus:
  • 4th month- just above symphysis pubis.
  • 5th month- midway b/w symphysis pubis & umbilicus.
  • 6th month- umbilicus.
  • 7th month- midway b/w umbilicus & xiphoid.
  • 8th & early 9th month- at xiphoid process.


Classification of signs of pregnancy in living:

A.Presumptive signs
  • Suppression of menstruation
  • Morning sickness
  • Sympathetic disturbances
  • Breast changes
  • Pigmentation of skin
  • Quickening
  • Vaginal changes
  • Urinary disturbances

B.Probable signs

  • Changes in abdomen
  • Softening of lower segment and os
  • Presence of cervical mucus plug
  • Braxton Hick’s sign
  • Ballottment
  • Uterine souffle
  • Biological tests

C.Positive signs of prgnancy:
  1. Fetal movements (after 5th month,at 24 weeks )
  2. Recognition of fetal parts (by abdominal examination)
  3. Fetal heart sound (160 bpm at 5th month, 120bpm at term),heard between 18-20 wks for first time.
  4. Radiograph of fetus (can be taken after 4th month)
  5. Ultrasound-G.S seen by 6th week

Pseudocyesis
-Spurious or phantom pregnancy
-Seen in women near menopause or those who are much desiring pregnancy
-All subjective symptoms of pregnancy including increase in abdominal size by abnormal fat deposition,or ascites occur
-even lady seen to have started labour like pains

Signs of prgenancy in Dead (on PM examination)
  • Presence of an ovum or fetus
  • Uterine changes
  • Presence of corpus luteum in one of the ovaries

Uterine changes:
  • Uterus thickened and enlarged
  • Length, breadth, & weight are increased
  • Chorionic villi are seen on microscopic examination

Posthumus child
  • -born after the death of father

MLI of pregnancy:
  • To escape hard labor or punishment
  • To avoid court attendance
  • In cases of property
  • In divorce cases
  • Black mailing
  • If a woman is charged of unchastity
  • Identification

Superfecundation-fertilisation of two ova which have been discharged by two separate acts of coitus commited at short intervals.

Superfoetation –fertilisation of second ovum in a woman who is already pregnant.

DELIVERY

Signs of recent delivery in living
  • General appearance- pale, exhausted & ill looking sunken eyes, slight increase in pulse and temperature.
  • After pains – intermittent contractions of uterus for the first 4-5 days after delivery.
  • Breasts- enlarged, contain colostrums, surface veins dilated & prominent, striae & Montgomery’s tubercle present
  • Abdomen- flaccid, wrinkled, striae gravidarum present
  • Fourchette- ruptured, posterior comissure destroyed
  • Vulva- bruised, tender & gaping
  • Vagina- lax, capacious, rugae begin to reappear about the third week

Uterus- enlarged, easily felt, palpate as a cricket ball
Soon after delivery- 2.5cm below umbilicus
10th day- on level with pelvic brim
2-3 weeks- returns to pelvic cavity
6 weeks- returns to normal size and position

Cervix- soft, patulous, may be lacerated. Internal os closes in first 24 hours, external os in two weeks.

Lochia- discharge from uterus and vagina for about 2-3 weeks.
  • Has a peculiar disaggreable odor
  • 1st 4-5 days- bright red with large clots- lochia rubra
  • Next 4 days- serous and pale in color- lochia serosa
  • After 9th day- yellowish grey or turbid- lochia alba until its final disappearance
  • If the blood or urine gives positive pregnancy test, strong evidence that pregnancy has been terminated recently. (likely to disappear in a week or 10 days)


Signs of recent delivery in dead:

  • Breast when cut open, may show milk
  • Uterus flabby and enlarged
  • Ovaries and fallopian tube congested, on section may show corpus luteum


Wednesday, September 7, 2011

Animal Poisoning



Classification of snakes

-Poisonous

Poisonous

A. Colubridae
Elapidae
Kobra
Krait
Mamba
2. Hydrophidae

Viperadae
Rattle snake
Pit vipers
Russel viper


Elapids: (Cobra, Krait)
  • Secrete neurotoxin- leads to local burning pain, muscular weakness, spreading paralysis, slow labored breathing, death is usually due to respiratory failure
  • Head is small
  • Pupils are round
  • Fangs are short, fixed and grooved
  • Cobra is found everywhere except Europe
  • Cardiotoxin found particularly in cobra venom is toxic to heart
  • Cobra has a hood which on the dorsal side often bears a double or single spectacle mark
  • Cobra grows to a length about 2 m.
  • Cobra venom fatal dose- 15 mg
  • Krait has a single or double white bands across the back and a creamy white belly
  • Kraits are nocturnal in habit
  • Kraits venom fatal dose- 6 mg

Vipers
  • Secrete vasculotoxic venom- intense local pain, swelling, ecchymosis and discoloration of surrounding tissue, oozing of bloody serum rapid feeble pulse, hemorrhage from natural orifice, cold and clammy skin, loss of consciousness, death from shock
  • Consists of pit vipers and pit less vipers
  • Pits are situated between the eye and nostrils
  • Head is big and triangular
  • Pupil is vertical
  • Fangs are long, movable and canalized
  • Can bite through clothes
  • Pit vipers are seldom dangerous but the russel viper, which is pitless viper, is dangerous.

Sea snake

  • Secrete myotoxic venom- generalized pain and stiffness, brown colored urine due to myoglobinuria, hyperkalaemic symptom, death due to respiratory failure
  • Small head and flat tail
  • Found in the vicinity of sea coast
  • Most of them do not bite


Difference

Poisonous

  • Belly scales are large and cover entire belly
  • Fangs are hollow like hypodermic needles
  • Tail is compressed
  • Two long fangs are present
  • Usually nocturnal
  • Head scales are small with enlarged central row of scales on back


Non-poisonous

  • Small, do not cover the entire belly

  • Fangs are short and solid

  • Tail is not much compressed
  • Several small teeth
  • Not so
  • Head scales are large


Delirient poison

Dhatura (thorn apple)
  • Solanaceae family- flowers are bell shaped, fuits are spherical with spinous projections
  • All parts of plants are poisonous, but seed and fruits are more
  • Active principle is hyoscine, traces of atropine, so it paralyses the parasympathetic system
  • S/S- dry mouth, dry face, restlessness, confusion, delirium, patient may become noisy or violent, hallucination (usually visual), amnesia, convulsion and death, tachycardia, dysrrhythmias, raised body temperatures.
  • Treatment- stomach wash with warm water and KMnO4, oxygen, catheterization for urinary retention, cold water sponging for pyrexia, i/v diazepam for convulsion, physostigmine
  • MLI- is a stupefying agent used for robbery, rape, and kidnapping; may be accidental, suicidal and homicidal
  • Fatal dose- 100 to 150 seeds crushed, 60 mg alkaloid
  • Fatal period within 24 hours

Atropa Balladona:

  • Also called deadly night shade
  • All part of plant are poisonous
  • Contain alkaloids, atropine, and hyoscymine
  • Treatment, sign and symptoms and postmortem findings same as dhatura
  • Fatal dose 10-15 berries, 100-125 mg atropine by mouth, 3mg by injection
  • Fatal period 24 hours

Cannabis indica or sativa
  • All parts are poisonous
  • Drug is used as “Bhang” (dry leaves and fruiting shoot, least potent), “Ganja” (flowering top of the female plant), “Charas or Hasis” (exudates obtained from leaves and stem)
  • First stimulates and depresses the vital centre

  • never causes death and its dangers are denied by many, though long-term users may develop psychotic states
  • and there is some evidence of genetic defects in the offspring of users

  • S/S- anxiety, excitement, euphoria, talkativeness, laughter, increased appetite, hallucinations, unproductive cough, dry mouth, run-amock (homicidal tendency),finally stage of narcosis (drowsiness, staggering gait, dilated pupil, rarely death)
  • Treatment- stomach wash, saline purgatives, symptomatic treatments
  • MLI- dangerous when driving, stupefying agent, run-amock, sadhus and pujaris use it
  • Fatal dose- Charas: 2gm/kg, Ganja: 8gm/kg, Bhang: 10gm/kg
  • Fatal period: 12hrs to 19 days

Cocaine:

  • Derived from the dry leaves of cocoa plant
  • Colorless, odorless, crystalline substance with a bitter taste
  • Administered through the oral mucus membrane, injection, inhalation
  • Ulceration of the nasal septum is always recorded as a complication of long-term nasal abuse of cocaine but this is, in fact, a rare phenomenon.
  • Cocaine produces hypertension, which (like amphetamines) may lead to cerebral bleeding. Dilated pupils hyperpyrexia, marked sweating and confusion may lead to coma and death from either respiratory depression or cardiac arrhythmia.
  • more potent form of cocaine called ‘crack’ has appeared
  • S/S- numbness of mouth, pyrexia, dilated pupil, increased sexual desire, happy and euphoric, delirium, tachycardia, tachypnoea, nausea, vomiting, muscular twitching, convulsion, collapse and death.
  • Treatment- stomach wash with warm water and KMnO4, symptomatic treatment
  • Postmortem finding- lungs edematous, signs of asphyxia or cardiac failure
  • MLI- aphrodisiac, used by prostitutes to constrict vagina, accidental, drug of addiction
  • Fatal dose- 1gm orally,
  • Fatal period- 2min to 4 hours

Tuesday, September 6, 2011

FORENSIC TOXICOLOGY


Definition
  • Toxicology-science dealing with properties,actions,toxicity ,fatal dose,detection,estimation of and the interpretation of result of toxicological analysis and treatment of poisons
  • Forensic toxicology deals with medical and legal aspects of harmful aspects of chemicals on human beings
  • Poison is a substance (solid,liquid or gas)which if introduced into the living body,or brought into contact with any part thereof,will produce ill health or death,by its constitutional or local effect or both.


CORRHOSIVE

  • Strong acid
  • Strong alkali

IRRITANT

1.Inorganic:
  • Non-metallic-phosphoros, chlorine, bromine
  • Metallic- arsenic, mercury, lead, zinc, copper

2.Organic:
  • Vegetable- castor seed, croton oil, aloe
  • Animal- snake bite, insect bite, cantharides

3.Mechanical:
  • Diamond dust
  • Powdered glass

SYSTEMIC

1.Cerebral:

  • Somniferant- opium and other alkaloid
  • Inibriant- alcohol, ether, chloroform
  • Deliriant- dhatura, balladona, cannabis

2.Spinal: nuxvomice
3.Cardiac: digitalis, tobacco, aconite
4.Asphyxiant: war gas, coal gas, sui gas
5.Peripheral: curare

Symptom characteristic of a particular poison
  • Violent convulsant
  • Quick death
  • Hallucination and delusion
  • Drowsiness
  • Colic and pronounced diarrhoea
  • Paralysis ,unconsciousness
  • Coffee brown vomitus with garlic odour
  • Bluish green vomitus
  • Black vomitus
  • Yellow vomitus
  • Strychinine
  • Cyanide
  • Dhatura or atropine
  • Opium, tranquiliser, hypnotic
  • Arsenic, lead
  • Carbolic acid, nicotine
  • Phosphorus,
  • Cuso4
  • Sulphuric acid
  • Nitric acid, chromic acid

Treatment of poisoning

1.Stop further administration

2.Removal of unabsorbed poison
  • Emesis
  • Gastric aspiration and lavage
  • Whole gut lavage
3.Check further absorption with antidote

  • Mechanical or physical example- oil, fat, milk, banana
  • Chemical- to neutralize poison, e.g. weak acid, weak alkali
  • Universal antidote like activated charcoal, milk of magnesia, tannic acid


4.Prevent further action of absorbed poison with chelating agent
  • BAL (Bristish, Anti-Lewisite for heavy metal poisoning)
  • EDTA for lead
  • Penicillamin for copper, lead and mercury
  • Dicobalt edetate for cyanide
  • Desferrioxamine for iron
5.Elimination of absorbed poison

  • Diuresis,
  • Sweating
  • Dialysis
  • Hemoperfusion, exchange transfusion
6.Treat general symptoms

CORRHOSIVE- H2SO4, HNO3, HCl, oxalic acid, acetic acid, caustic potas, NH4CO3

Suicidal ingestion of a corrosive substance (Lysol). Spillage around the mouth has run down the neck and onto the chest.

  • The symptoms are obvious and immediate, with pain at the sites of exposure, usually the mouth and on the skin, difficulty in swallowing, chest pain, abdominal pain, vomiting, difficulty in breathing, choking.
  • If the amount ingested is significant, there will be signs of shock, with collapse, a weak and rapid pulse, hypotension and possibly death, even if treatment is available straightaway.
  • Avoid gastric lavage

Sulphuric acid:

  • Colorless, oily liquid, damages the tissue by dehydration
  • Signs and symptoms- burning pain in mouth, throat down to stomach, nausea, vomiting, dark brown or black vomitus mixed with blood, chalky white teeth, swollen or excoriated lips, difficulty breathing if larynx involved, weakness and collapse
  • Treatment with- neutralisation with milk of magnesia, milk or lime water, analgesia for pain, corticosteroid, fluid replacement
  • Gastric lavage is contraindicated
  • Fatal dose- 10-15 ml, fatal period is 12-24 hours.
  • MLI- used for suicide, mostly accidental, abortificent,vitriolage(throwing acid)
  • Cause of death-circulatory collapse,spasm or oedema of glottis,collapse d/t perforation of stomach

Nitric acid/Aqua Fortis:

  • Yellowish liquid, choking odor, colorless irritating fumes on exposure to air
  • S/S- like H2SO4 except tissues stained yellow, abdominal distension due to gas formation, lacrimation and conjunctivitis, death may occur d/t pulmonary edema.
  • MLI- used for suicide, accidental, homicidal (rare).
  • Fatal dose- 15-20 ml, fatal period- 12-24 hours.

HCl / Muriatic acid:
  • Pungent, colourless fuming liquid, less corrosive ,is in stomach. destroys mucosa.
  • S/S- as H2SO4, HNO3 but milder & more respiratory symptoms being volatile
  • PM findings- skin and mucus membrane whitened, ashy grey or black; errosive esophagitis; stomach is red, perforation is less common.
  • Fatal dose- 15-30 ml, fatal period is 18-30 hours.



Oxalic acid:

  • Although not as corrosive as the mineral acids, oxalic acid and potassium quadroxalate are very toxic, death often occurring within a hour or so if the solid or concentrated solution is taken.
  • They are used extensively as bleach for stain removal and in many other trades and industries .
  • Natural constituent of many plants e.g.spinach,cabbage
  • Colorless, prismatic crystals, rapid poison
  • S/S- sour taste, burning in throat, stomach
  • rarely damage skin but readily corrode the mucosa;
  • purging & tenesmus; stools contain blood; low BP; skin cold & clammy
  • Treatment- give chalk in water; gastric lavage; gastric purgatives; i/v calcium gluconate and calcium chloride(antidote of any oxalate is calcium which binds and forms,calcium oxalate); i/m morphine for pain; inj. coramine to elevate BP
  • Fatal dose- 15 gms, fatal period is 1-2 hours.


Carbolic acid/ phenol:
  • Long, colorless, prismatic needle shaped crystal
  • Largely used as antiseptic and disfectant
  • Turns pink on exposure to light and air, intense penetrating odour
  • S/S- hot burning sensation from mouth to stomach, corroded lip, mouth, tongue; nausea, vomiting; pulse small, BP low; greenish appearance of urine k/a carboluria; death from respiratory paralysis as phenol is a respiratory depressant.
  • T/t- milk, vegetable oil or any demulcent; stomach wash; inj. morphine for pain; artificial respiration for shock; antibiotic prophylaxis of pneumonia
  • Fatal dose- 15 gms, fatal period is 3-4 hours.

Aspirin/ Acetyl salicylic acid:
  • White crystalline powder for headache and pyrexia
  • S/S- n/v, subconjunctival hemorrhage; petechiae over face and eyelids; gum bleeding, GIT and urethral bleeding; tinnitus and deafness; deep and rapid respiration; pulse rate increased; delirium, agitation, confusion, coma and convulsion; death due to respiratory failure
  • T/t- gastric lavage; KCl to treat hypokalaemia; milk as demulcent; Vit. K for bleeding; oxygen for cyanosis; hemodialysis in very severe cases
  • PM findings- petechial hemorrhage on face and neck; frothy fluid from mouth and nose; cyanosed; erosion of GIT

Heavy metal poisoning:

  • The literature of nineteenth-century European forensic medicine is full of notorious cases of murder by arsenic, antimony and mercury.
  • Arsenic
  • Metallic arsenic,black is not toxic
  • It is the compounds of arsenic, particularly arsenious oxide and the various arsenites of copper, sodium and potassium, that are toxic to humans, inteferes with cellular respiration.
  • Vascular endothelium appears to be particularly susceptible to the toxic effects of arsenic.
  • In acute poisoning, if sufficient chemical is ingested, there may be initial burning in the mouth and then, after an interval, signs of intense gastroenteritis develop: abdominal pain, nausea, burning regurgitation and vomiting. Diarrhoea ensues and this, together with the sickness, leads to prostration, mainly from dehydration and electrolyte imbalance. death in 1 to 3 hrs in severe ac. Poisoning due to shock and peripheral vascular failure.
  • In chronic poisoning, a classic state of ill-health develops, Loss of appetite, mild nausea, some vomiting, jaundice, loss of weight and anaemia are relatively non-specific symptoms.

  • More specific signs can be seen in the skin, where chronic arsenical poisoning causes hyperkeratosis of the palms of the hands and soles of the feet produce band of opacity in the nail k/a MEES-ALDRICH line.
  • A speckled pigmentation of the general skin surface sometimes described as a ‘raindrop’ appearance (finely mottled brown change especially over eyelid,temples,and neck).
  • loss of hair, brittle nails and a peripheral neuritis with itching, tingling and paraesthesia of the extremities
  • The fatal dose is variable, but 200–300 mg of arsenious oxide are likely to be needed for acute fatal toxicity.
  • At autopsy, little may be found in acute deaths apart from a haemorrhagic gastritis. The stomach mucosa has been likened to red velvet, due to the bleeding
  • Subendocardial bleeding may be seen in the left ventricle, though this is not specific to arsenic and can be seen in any death when there has been a precipitous drop in blood pressure due to ‘shock’.

  • T/T-stomach thoroughly washed with fluid,BAL is given,penicillamine may be used in place of BAL.Demulsant decrease the irritation.glucose –saline helpful to combat shock.

Lead

Lead can be administered by oral,inhalation,through skin,mucous membrane,I.V
Causes spasm of capillaries and arterioles
Toxic effects results from fixation of lead into tissues
S/S-
acute poisoning -sweet,metallic taste,burning in throat,V/N,jaundice,feeble pulse,drowsiness,insomnia,headache,convulsion,numbness.
chronic poisoning- anorexia,metallic taste in mouth,constipation,colic,Burton s line(blue pigmentation on gingival margin),anemia and punctate basophilia,peripheral neuritis(foot drop and wrist drop)arthralgias
Management-EDTA as chelating agent,diazepam for convulsion,morphine and pethidine for pain,physiotherapy for paralysis.
MLI-mostly accidental d/t use in utensils,lead pipes.
FD=20-40mg, fatal period =uncertain,2-3 days

Mercury

  • Mercury is usually an industrial or environmental poison.
  • Although historically some deaths occurred from its use in medicine, mercurial diuretics and antiseptics are now almost a thing of the past.
  • Acute poisoning resembles that of arsenic and antimony: gastrointestinal symptoms are common,
  • But there are also excessive salivation and signs of renal failure.
  • Chronic mercury poisoning is almost wholly industrial in nature and
  • The clinical hallmarks are gingivitis, loose teeth, salivation, black gums, mandibular necrosis, peripheral neuritis, encephalopathy and renal failure.

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