Biomedical subjects

B Daunter

Publications and source records attributed to B Daunter.

60 records · Page 4Linked to original sources

PubMedDate not supplied

Carcinoembryonic antigen and beta 2-microglobulin as serum tumor markers in women with genital cancer.

A comparative study of carcinoembryonic antigen (CEA) and beta 2-microglobulin (beta 2-MG) in serum was made by radioimmunoassay in 77 women with genital cancer. With a positive level defined as 5 ng of CEA/ml and 3.0 microgram of beta 2-MG/ml, CEA was positive in 31% of the women with cancer of the corpus, 36% of those with cancer of the cervix and 36% of those with cancer of the ovary the corresponding figures for beta 2-MG were 6%, 27% and 56%, respectively. The additional use of beta 2-MG provided an increase in positive results, especially in cases of cancer of the ovary. A direct relationship between the extent of tumor and serum marker level was more evident for beta 2-MG than CEA. There was no correlation between serial levels of CEA and beta 2-MG in most patients. CEA levels appeared to predict subsequent tumor behavior more accurately in patients with good prognoses (ie, complete or partial tumor response), whereas beta 2-MG levels gave the same prediction in those with bad prognoses (ie, nonresponsive or progressive tumor).

Adenocarcinoma↗

PubMedDate not supplied

Seminal plasma biochemistry. III: Characterization of coagulum components.

Human seminal plasma components involved in coagulum formation have been isolated by liquefaction and reformation of the coagulum in acidic and neutral buffers, respectively. The SDS-PAGE profile of the isolated coagulum (recoagulum) is similar to that reported for the native coagulum immediately following liquefaction. Thus the recoagulum may be considered to represent the native coagulum. Electrophoresis of the recoagulum under non-denaturing conditions reveals the presence of both positively and negatively charged components. These components are sialoglycoproteins that bind copper. Based on these results, a possible mechanism for coagulum formation and liquefaction is discussed.

Electrophoresis↗

PubMedDate not supplied

Seminal plasma biochemistry II: seminal plasma and spermatozoal cytidine monophosphate-sialic acid synthetase and sialyltransferase activities.

The zona pellucida receptor for spermatozoa has not been identified and the mechanism by which spermatozoa traverse the zona pellucida has not been elucidated. It is proposed that the zona pellucida receptor is a glycoprotein and the receptor per se is galactosamine or N-acetyl galactosamine. The mechanism by which spermatozoa transverse the zona pellucida may be by its structural modification, by the transfer of spermatozoal sialic acid. In addition, male infertility resulting from oligozoospermia or polyzoospermia, may be due to lack of spermatozoal bound sialyltransferase. A total of 43 semen samples were examined for cytidine monophosphate-sialic acid synthetase and sialyltransferase activities. It was found that both these enzymes are present in seminal plasma and bound to the spermatozoa. The spermatozoal bound enzymes may be derived from the seminal plasma which may be a limiting factor in terms of infertility.

Humans↗

PubMedDate not supplied

Scanning electron microscopy and histological examination of human seminal plasma coagulum.

Human seminal plasma coagulum was examined by S.E.M. and light microscopy using various preparatory techniques. Two types of structures were observed; porous and laminated. A consistent finding using all the preparatory techniques was the presence of the majority of the spermatozoa on the surface of the coagulum as opposed to the interior. Those spermatozoa present in the interior of the coagulum are attributed to the invagination of the surface layer. The presence of spermatozoa on the surface of seminal plasma coagulum plays an important role in concentrating spermatozoa in close proximity to the cervical os. This allows spermatozoa to reach cervical mucus rapidly and minimizes the time they must remain in the unfavourable environment of the vagina.

Adult↗

PubMedDate not supplied

Osmolarity of human seminal plasma.

Osmolarity of human seminal plasma was found to be higher than that of human blood plasma. No significant relationship was found between osmolarity, spermatozoal concentration and liquefaction time. Osmolarity was shown to correlate with spermatozoal motility and optimum motility was observed between 360 and 380 mOsm.

Humans↗

PubMedDate not supplied

Seminal plasma biochemistry. I. Preliminary report: a possible mechanism for the liquefaction of human seminal plasma and its relationship to spermatozoal motility.

Based on indirect evidence it has been suggested that the liquefaction of human seminal plasma involves fibrinolytic and proteolytic enzymes and that the coagulum is formed by proteins. In this preliminary investigation evidence is presented for the involvement of seminal plasma sialyltransferase in liquefaction which suggests that the coagulum may be composed of glycoproteins. It is proposed that the glycoproteins form a polymer by the chelation of divalent metal ions via the carboxylic acid moieties of the sialic acid groups of the glycoproteins. The glycoprotein polymer may then be dismantled by the reduction of the meal ions by the oxidation of L-ascorbic acid, possibly allowing enzymes to complete the liquefaction process. A total of 100 semen samples from 30 male subjects whose semen profiles were considered "normal" by an independent assessor, were examined for the following: (i) liquefaction time of the seminal plasma; (ii) seminal plasma sialyltransferase activity; (iii) spermatozoal motility, defined as directional or nondirectional; (iv) spermatozoal count, and (v) seminal plasma content of free L-ascorbic acid, dehydroascorbic acid and glutathione. Linear regression analysis showed a significant correlation between sialyltransferase activity and the liquefaction time for seminal plasma. Similarly, multilinear regression analysis of the data showed that as the seminal plasma levels of L-ascorbic acid, total dehydroascorbic acid and glutathione increase, there is a decrease in spermatozoal motility and a decrease in the liquefaction time of the seminal plasma. The possible metabolic relationship of seminal plasma L-ascorbic acid and glutathione is discussed and a metabolic pathway is suggested.

Ascorbic Acid↗