Tag: Seminal stains.

Seminal stains.

Seminal stains.

Q. 1 Best test for seminal stains is:
 A Barbeiros test
 B Acid Phosphatase test
 C Florence test
 D Alkaline Phosphatase test
Q. 1 Best test for seminal stains is:
 A Barbeiros test
 B Acid Phosphatase test
 C Florence test
 D Alkaline Phosphatase test
Ans. B

Explanation:

The acid phosphatase test- 1. Level > 25 kA Unit is specific for the test or Undiluted semen has an acid phosphatase activity of 340 – 360 Bodansky U/ml, it is higher in humans as compared to animals. 2. It is +ve also by human RBCs, semen of higher apes and juice of cauliflower. 3. The prostatic secretion element of seminal fluid contains  a  very  much  higher  percentage  of  acid  phosphatase.  4.  This  test  is  conclusive  in  the  absence  of demonstrable sperms or in aspermia. 5. Is a quantative test.


Q. 2

Dried semen stain in clothes is identified by

 A

UV light

 B

Spectroscopy

 C

Magnifying lens

 D

Infra red

Q. 2

Dried semen stain in clothes is identified by

 A

UV light

 B

Spectroscopy

 C

Magnifying lens

 D

Infra red

Ans. A

Explanation:

UV light [ Ref: Reddy 29/e, p 377-378; Parikh 6/e, p 7.26-7.271

  • Seminal stains have to be detected in sexual offences. These have to be differentiated from those due to starch, pus, vaginal discharge, urine & egg albumen.
  • Seminal stains may be examined by four methods – (1) Physical (2) chemical (3) Microscopic (4) Electrophoretic

1)   Physical examination – A preliminary examination under filtered ultraviolet light can be made. Stains of urine, vaginal discharge and seminal fluid show a bright fluorescence. The fluorescence of seminal stains is of a bluish white colour & such stains are selected for further examinations.

2)   Chemical examination – Following tests can be done

  • Florence test – It is based o the presence of choline in semen. After adding reagent, dark brown crystals are formed.
  • Barberio’s test – It depends upon the presence of spermine in semen. Yellow, needle shaped, rhombic crystals of spermine pictrate are produced when reagent is added.
  • The acid phosphatase test – A high concentration of acid phosphatase is found only in the semen of human beings & monkeys. This is a quantitative test. The amount of acid phosphatase is estimated. Inhibition of acid phosphatase by 1-tartaric acid, though non specific, is a valuable screening test.
  • Creatine phosphokinase test – Spermatozoa contain a high concentration of cratine phosphokinase. Levels over 400 U/ml is almost diagnostic of semen. The enzyme is stable and can be detected even in old stains of 6 months.
  • Choline and spermine test – Liquid semen and dried seminal stains can be identified by a thin layer chromatographic technique. The test is based on the unique combination of choline & spermine which is present only in semen.
  • Ammonium molybdate test – when reagent is added to stain, a deep yellow colour from the presence of phosphorus is produced.
  • Immunological method – MHS-5 from seminal vesicles and Mab 4 E6 can be detected on the sperm cells & in ejaculated fluid. Prostate specific antigen (PSA, P30) test has replaced the quantitative analysis for acid phosphatase [Fluroscent in situ hybridisation (FISH) has been suggested as a specific & sensitive test for detection of male epithelial cells in the post coital vagina upto one week]

3) Microscopic examination – Involves identification of spermatozoa under the microscope. Fluorescence microscopy is based on the principle that the Y-chromosome is fluorescent to quinacrine.

4) Electrophoretic methods

  • Acid phosphatase isoenzyme test – Polyacrylamide gel electrophoresis followed by staining with methyl umbelliferyl phosphate reagent makes the seminal acid phosphatase to be distinguished from the acid phosphatase present in other substances & in vaginal secretion.

This is superior to LDH isoenzyme method since semen can be identified in the absence of sperms as in azoospermic or vasectomised persons.

  • Lactate dehydrogenase (LDH) isoenzyme Test – Sperm specific LDH isoenzyme can be separated from other LDH isoenzymes of semen by polyacrylamide gel electrophoresis.

Proof of semen: The only absolute proof of semen is the finding of at least one unbroken spermatozoan, or electrophoretic LHD isoenzyme detection of sperms.

  • In case of azoospermia, vasectomy or very old persons a stain will be seminal if it gives

– characteristic fluorescence in UV light

– positive 1-tartarate acid-phosphatase and

– High levels of acid phosphatase & creatine phosphokinase

or electrophoretic seminal acid phosphatase or PSA (P30) positive

  • Species (Human or animal) is confirmed by precipitin test as in blood stains.
  • Source (from which person) is identified by DNA & different grouping systems such as ABO, GM, PGM & GLO-I. New test
  • Commercial ELISA, the SEMA®assay, for a seminal vesicle-specific antigen (SVSA) provides highly sensitive detection of semen but are costly .

Q. 3 Which is a not an essential criteria according to WHO for normal semen analysis
 A Sperm count > 20 million/ml
 B Volume > 1 ml
 C Sperm with normal morphology (strict criteria) > 15%
 D Motility > 25% with rapidly progressive motility
Q. 3 Which is a not an essential criteria according to WHO for normal semen analysis
 A Sperm count > 20 million/ml
 B Volume > 1 ml
 C Sperm with normal morphology (strict criteria) > 15%
 D Motility > 25% with rapidly progressive motility
Ans. B

Explanation:

Volume > 1 ml [Ref William’s Gynaecology p. 449; http//www.gfiner.ch/end%•pgi/network]

THE W.H.O. RECOMMENDS THE FOLLOWING NORMAL VALUES

Volume

Sperm

Total sperm number

Percent mobility

Forward progression

Normal morphology

Round cells

Sperm agglutination

> 2 ml

concentration > 20 million / ml or more

> 40 million/ejaculate

> 50% with forward progression

> 25% with rapid linear progression

> 2 (scale 0-4)

> 30% normal (W.H.O. criteria)

> 14% normal (Kruger and strict criteria)

< 5 million/rnl

< 2 (scale 0-3),w.b.c fewer than I x106 / ml

  • The normal sperm morphology is currently being reassessed by W.H.O
  • In the interim the proportion of normal forms accepted by the laboratories in the U.K is either the earlier W.H.O limits of 30 or 15% based on strict morphological criteria.



Q. 4

Color of dried semen becomes yellow to brown. Dried semen stain in clothes is identified by:

 A

UV light

 B

Spectroscopy

 C

Magnifying lens

 D

Infrared

Q. 4

Color of dried semen becomes yellow to brown. Dried semen stain in clothes is identified by:

 A

UV light

 B

Spectroscopy

 C

Magnifying lens

 D

Infrared

Ans. A

Explanation:

When dried semen is examined under filtered ultraviolet light, they show a fluorescence of a bluish-white colour, which is not specific as other albuminous materials such as nasal, leucorrhoeal discharges and detergents also fluoresce.

Fluorescence depends on choline of semen.

Ref: The Essentials of Forensic Medicine and Toxicology, 27th edition, Page 369.


Q. 5

Which of following tests in used to detect semen?

 A

Phenolphthalein test

 B

Reine’s test

 C

Barberio’s test

 D

Paraffin test

Q. 5

Which of following tests in used to detect semen?

 A

Phenolphthalein test

 B

Reine’s test

 C

Barberio’s test

 D

Paraffin test

Ans. C

Explanation:

C i.e. Barberio’s test :

  • Barberio’s test is used for identification of seminal stains

Few drops of barberio’s reagent (containing pieric acid) are added to the seminal stain.

Positive test is indicated by formation of Yellow and needle shaped crystals of spermine picrate.

(Spermine in seminal stain reacts with picric acid to form these crystals)

  • Phenolphthalein test  (Kastle-Meyer test) is used for identification of haemoglobin in blood stains – Parikh 6th/7.16
  • Paraffin test  (or Dermal nitrate test) is used to detect gun powder on skin i.e. to determine if suspect had discharged a firearm- Parikh 6″/7.39
  • Reine’s test  has not been mentioned in forensic literature

Forensic tests to detect

Seminal Stain

Blood Stains

– Barberio’s testO

– Benzidine testQ

– Fluorence testQ

– Phenophthalein (Kastle‑

– Acid phosphatase

Meyer) testQ

testQ

– Takayama’s

– Creatine phosphatase

Haemochromogen crystal

test

testQ

– Elisa test

– Teichmann’s Haemin crystal

testQ

 

– Spectroscopic test


Q. 6

Spermin is detected in semen by which test‑

 A

Barberio test

 B

Florence

 C

ELISA

 D

Agglutination inhibition

Q. 6

Spermin is detected in semen by which test‑

 A

Barberio test

 B

Florence

 C

ELISA

 D

Agglutination inhibition

Ans. A

Explanation:

A i.e. Barberio test


Q. 7

All are tests for seminal stains except:           

March 2012

 A

Florence test

 B

Creatine phosphate test

 C

Takayama test

 D

Barberio test

Q. 7

All are tests for seminal stains except:           

March 2012

 A

Florence test

 B

Creatine phosphate test

 C

Takayama test

 D

Barberio test

Ans. C

Explanation:

Ans: C i.e. Takayama test

Stains and features

  • If semen is present, florence test will show dark brown crystals of choline iodide.
  • Levels over 400 units of CPK/ ml are almost diagnostic of seminal stains
  • Blood stains with Takayama reagent produces pink, feathery crystals of haemochromogen/ reduced alkaline haematin.
  • If prostatic secretion is present, yellow needle shaped rhombic crystals (spermine picrate) are seen

Q. 8

Florence test is used for: 

Delhi 06

 A

Blood stains

 B

Seminal stains

 C

Salivary stains

 D

Sweat stains

Q. 8

Florence test is used for: 

Delhi 06

 A

Blood stains

 B

Seminal stains

 C

Salivary stains

 D

Sweat stains

Ans. B

Explanation:

Ans. Seminal stains



Seminal stains.

Seminal stains.


Introduction.

  • Sensabaugh in 1977 reported the event of isolation of p30 in human seminal  fluid.  It is a glycoprotein of prostate origin.
  • Detection  of seminal  stains  becomes  important  in cases  of  rape, attempted  rape, sexual  murders of  female, kidnapping, sodomy, bestiality, adultery  and  indecent  assault  etc.
  • Seminal  stains  are  generally found  on  the  clothing, but  may be present  on  the  body  of  the  victim  or  accused,  on  the  bed  clothes,  site of offence,  seat  of motor car; on the  floor  or on  the grass.
  • Normal semen reference pH range is 7.2 to 7.8. Variations in volume and low pH may be  due to congenital abnormalities of the genital tract or to obstruction.

Tests  to  detect  semen are  :

A) Chemical  tests  :These tests  are  divided  into  :

1) Microchemical  tests  :

Florence  test:

  1. This test was discovered by Dr.Florence in the year 1886.
  2. When Florence reagent (PotassiumIodide+Iodine+Water) is applied to the slide it produces rhomboidal shape  dark crystals of choline periodide.
  3. choline can be detected if swab is collected within one day of sexual act,

Barberio’s  test:

  1. Invented by Barberio in the year 1905.
  2.  When the questioned stain is  allowed to react with picric acid it leads to the formation of yellow needle shaped  spermine picrate crystals.

2) Enzyme tests: Since spermatozoa contain gram positive protein, the  presence of spermatozoa will be confirmed by microscopic appearance of purple bodies

Acid phosphatase & specific glycoproteins:

  1. This test is adopted because of high acid  phosphatase activity of semen.
  2. Stability of  acid phosphatase activity in seminal stain depends on temperature

3) Ammonium  molybdate  test:  lt  gives  deep  yellow  colour, due to  presence  of phosphorus. 

B)  Microscopic examination : It  is  done  to  demonstrate the  presence of  spermatozoa in  the  vaginal fluid  or in  stain. 

C)  Biological  examination:

  • Precipitin  test  :  To  know  the  species  to  which  semen  belongs.
  • Blood  group  can  be  known  from  semen

D)  UV light:

  • Invisible,  softened  and dry  semen  stains of the  clothes can  be  rendered  distinct  by  the  filtered UV light which  produces  bluish  fluorescence.
  • A mercury lamp inside of the unit produces a high intensity of UV (320-400nm) and visible light (400-700 nm) which was developed  to detect biological stains even in daylight.

E) Testes  for  determination  of  specific protein  component (e.g. LDH  isoenzyme):

  • These are  immunoelectrophoresis,  gel  diffusion  precipitation, gel  electrophoresis,  immunodiffusion,  isoelectric focusing  and TLC (thin  layer  chromatography).

Exam Important

A) Chemical  tests  :These tests  are  divided  into  :

1) Microchemical  tests  :

Florence  test:

  1. This test was discovered by Dr.Florence in the year 1886.
  2. When Florence reagent (PotassiumIodide+Iodine+Water) is applied to the slide it produces rhomboidal shape  dark crystals of choline periodide.
  3. choline can be detected if swab is collected within one day of sexual act,

Barberio’s  test:

  1. Invented by Barberio in the year 1905.
  2.  When the questioned stain is  allowed to react with picric acid it leads to the formation of yellow needle shaped  spermine picrate crystals.

2) Enzyme tests: Since spermatozoa contain gram positive protein, the  presence of spermatozoa will be confirmed by microscopic appearance of purple bodies

Acid phosphatase & specific glycoproteins:

  1. This test is adopted because of high acid  phosphatase activity of semen.
  2. Stability of  acid phosphatase activity in seminal stain depends on temperature

3) Ammonium  molybdate  test:  lt  gives  deep  yellow  colour, due to  presence  of phosphorus. 

B)  Microscopic examination : It  is  done  to  demonstrate the  presence of  spermatozoa in  the  vaginal fluid  or in  stain. 

C)  Biological  examination:

  • Precipitin  test  :  To  know  the  species  to  which  semen  belongs.
  • Blood  group  can  be  known  from  semen

D)  UV light:

  • Invisible,  softened  and dry  semen  stains of the  clothes can  be  rendered  distinct  by  the  filtered UV light which  produces  bluish  fluorescence.

 

Don’t Forget to Solve all the previous Year Question asked on Seminal stains.

Module Below Start Quiz

Malcare WordPress Security