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E T Blake

Publications and source records attributed to E T Blake.

13 recordsLinked to original sources
PubMed1987

Evidence that "vaginal peptidase" is a bacterial gene product.

A peptidase has been described in vaginal samples, termed "vaginal peptidase." This enzyme has been proposed as a tissue specific marker for vaginal debris. We have explored the presence of this enzyme in vaginal swabs from alleged sexual assault victims and volunteer donors as well as bacterial cultures. These studies reveal that "vaginal peptidase" is composed of a family of peptidase isozymes that originate from several bacterial species. The characterization of "vaginal peptidase" as a tissue specific marker for vaginal debris is premature.

Bacteria↗
PubMed1987

Progressive desialidation of human transferrin.

Transferrin is a serum glycoprotein which contains four sialic acid residues located at the end of two branched carbohydrate structures. The presence of these four acidic residues influences the electrophoretic mobility of the transferrin molecule. Alterations in the electrophoretic mobility of transferrin may be encountered in forensic science case work, particularly in association with postmortem samples. These altered transferrins usually appear in a highly stylized "ladder" banding pattern. To determine whether these altered transferrins are the result of sialic acid removal, serum samples of known transferrin type were treated with neuraminidase. These experiments support the hypothesis that the "ladder" banding pattern of transferrin observed in some case samples is due to the removal of sialic acid residues by bacterial or endogenous neuraminidase. These studies also demonstrate that partially desialidated transferrin variants cannot be clearly typed until the sialic acid is completely stripped from the transferrin molecule. Reliable typing of partially desialidated samples can be accomplished by treating these samples with neuraminidase.

Electrophoresis, Agar Gel↗
PubMed1985

Postcoital detection of a male-specific semen protein. Application to the investigation of rape.

Identification of semen in vaginal fluid may provide documentation of sexual contact in alleged victims of rape. We describe an enzyme-linked immunosorbent assay for a semen glycoprotein of prostatic origin, designated p30. This test detects as little as 3 ng of the p30 antigen per milliliter in various body fluids. Semen from normal and vasectomized men contains high levels of p30 (mean, 1.55 mg per milliliter of seminal plasma), and urine from men contains low levels (mean, 260 ng per milliliter). However, the antigen cannot be detected in body fluids from women, including vaginal fluid and urine, suggesting that p30 may be a male-specific antigen. The p30 antigen was detectable in vaginal fluid for a mean period of 27 hours after coitus, as compared with 14 hours for prostatic acid phosphatase. Of 27 vaginal fluid samples from women who were allegedly raped in which the acid phosphatase test was negative, 7 (26 per cent) were unequivocally positive for p30 by our assay. We conclude that the assay for p30 offers a more sensitive and specific method of semen detection in rape investigation than the enzyme assay for prostatic acid phosphatase.

Acid Phosphatase↗
PubMed1980

Genetic markers in semen. III: Alteration of phosphoglucomutase isozyme patterns in semen contaminated with saliva.

Contamination of semen by saliva can result in the alteration of seminal phosphoglucomutase (PGM1) isozyme patterns. The alteration is characterized by the gradual loss of the a and b isozyme bands the concomitant generation of anodal bands; eventually, all PGM activity is lost. The conversion of PGM isozyme patterns has been shown to be due to a dialyzable heat-labile factor in saliva and a nondialyzable heat-labile factor in semen. The implications of this conversion for PGM typing in sexual assault evidence are discussed.

Chemical Phenomena↗
PubMed1978

A microliter oxygen electrode system for sperm suspensions.

A new polarographic oxygen electrode system is described which can accept sperm suspensions with volumes as low as 50 microliters. In this configuration, the electrode tip forms the base of the suspension reaction chamber, and there is no stirring. Consequently, structured fluids such as cervical mucus can be applied. Measurements can be performed in as little time as 10 minutes. The system reliably measures oxygen consumption rates as low as 0.1 mm Hg/minute, so that mammalian sperm suspensions with concentrations of the order 1 X 10(6)viable cells/ml can be applied. Sample experiments, comparing the oxygen uptake of human spermatozoa in semen and in Tyrode's solution, are described.

Adult↗
PubMed1976

Sperm diaphorase: genetic polymorphism of a sperm-specific enzyme in man.

Human sperm contains en enzyme with diaphorase activity that appears to be unique to sperm. Electrophoretic analysis of the diaphorase activity in sperm of different individuals reveals three phenotypic patterns. This polymorphism can be explained in terms of two alleles segregating at an autosomal locus; the allele frequencies have been determined to be 0.71 and 0.29. This appears to be the first reported example of a sperm-specific genetic polymorphism in man; its existence raises a number of genetic and biochemical questions.

Biological Evolution↗