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Biomedical subjects

B Landau

Publications and source records attributed to B Landau.

At least 37 records · Page 2Linked to original sources
PubMed1982

Estimation of hyaluronidase activity of human semen and its relationship with sperm density by means of a simplified method.

Hyaluronidase activity was examined in 109 specimens of human semen of various sperm densities, seminal plasma, and spermatozoa sedimented by centrifugation. We used a modification of a method originally devised for estimation of hyaluronidase activity in Clostridia and which was bases on measurements of the area of hyaluronate digestion in agar plates. Enzyme activities in both semen and seminal plasma increased with increase in sperm density. The activity in seminal plasma, which appeared promptly after liquefaction and represented enzyme released from spermatozoa, ranged from 31% to 61% of the activity in semen. Activities of spermatozoa in sediments exhibited lower values than those calculated for sperm of whole semen, possibly due to leakage. Both activities, calculated per million sperm cells, gradually increased with decrease in sperm density. The possibility that with severe oligozoospermia the acrosome may become less prone to enzyme release or that the initial activity per cell may increase is discussed. These phenomena would represent additional characteristics of oligozoospermia.

Humans↗
PubMed1981

Spatial knowledge and geometric representation in a child blind from birth.

A series of experiments demonstrated that a congenitally blind 2 1/2-year-old child-as well as sighted but blindfolded children and adults-can determine the appropriate path between two objects after traveling to each of those objects from a third object. This task requires that the child detect the distances and the angular relationship of the familiar paths and that she derive therefrom the angle of the new path. Our research indicates that the locomotion of the young blind child is guided by knowledge of the Euclidean properties of a spatial layout and by principles for making inferences based on those properties.

Auditory Perception↗
PubMed1980

Some properties of acid and alkaline phosphatase in seminal fluid and isolated sperm.

Activities of acid and alkaline phosphatases were examined in spermatozoa isolated from 177 semen samples differing in sperm counts. Alkaline phosphatase was also determined in seminal fluid. The enzymes were assayed using disodium p-nitrophenyl phosphate as substrate and were studied with respect to susceptibility to various concentrations of tartrate (acid) and to heat (alkaline). Electrophoretic separation of alkaline phosphatase from seminal fluid was performed using an Helena apparatus. The results showed that acid phosphatase activity in spermatozoa decreased with increase in sperm densities and that elevation of tartrate from 0.028 to 0.17 M usually correlated an inhibition of the enzyme from 72% to 78% (mean values). Alkaline phosphatase was very low in sperm and generally below the sensitivity of the method used. Activity of alkaline phosphatase in seminal fluid showed a tendency to increase with the increase in sperm counts, but the significance of differences between groups was not statistically valid. Exposure of seminal fluid to 55 degrees C for 16 min resulted in enzyme inactivation of about 90% and in this respect the alkaline phosphatase resembles the enzyme of bone origin. The electrophoretic pattern, however, did not confirm this view and the type of alkaline phosphatase in seminal fluid is not clear.

Acid Phosphatase↗
PubMed1980

Properties of spermatozoa from normospermic and oligospermic human semen fractionated on columns of discontinuous gradients of albumin.

One hundred and twenty-eight samples of human semen, divided into four groups according to sperm counts, were fractionated on two types of columns of discontinuous gradients of bovine serum albumin (3%, 15%, or 7.5%, 17.5%). In addition to morphology and motility, protein and DNA contents of spermatozoa as well as microscopical pictures of their sediments were examined in order to assess sperm sensitivity to damage in the course of common isolation procedures. The proportions of morphological normalcy and motility grades within the groups were higher in the bottom column fractions than in the middle ones; both showing prevalence over parent semen. Motility percentages were also higher in the bottom than in middle fractions, but no prevalence over parent semen was observed. Protein and DNA contents of spermatozoa were similar in the two fractions within the same group. Comparison between groups revealed an increase in percentages of normal morphology and motility and a decrease in protein and DNA with elevation of sperm density. Microscopic examinations revealed similar degrees of contamination in both fractions which were more abundant in oligospermia than in normospermia. It is suggested that sperms with better morphology and motility are as sensitive to common laboratory procedures as cells of lower quality originating from the same specimen.

Cell Fractionation↗
PubMed1979

Acid phosphatase activity in human semen.

Acid phosphatase activity was examined in normal and abnormal human semen of individuals not suffering from testosterone deficiency. No differences in enzymatic activity between the examined groups were observed. The presence of tartaric acid caused an inhibition of about 95% of enzymatic activity.

Acid Phosphatase↗
PubMed1979

High sperm densities and the quality of semen.

Thirty semens with sperm densities above 200 million per milliliter from patients with fertility disorders were examined for volume, motility, vitality, and morphology of spermatozoa, and for fructose content as well as for percentile decreases with time of activity and viability. In addition, blood levels of follicle stimulating hormone, luteinizing hormone, testosterone, and prolactin were estimated. Percentages of motility, vitality, and morphological normality, motility grades, and percentile decreases in both activity and viability were found to be comparable with those of oligospermic specimens. On the average, volume of semens were lower by about 30% than in normo- and oligospermia. 42% of the investigated semens had low fructose values (below 1 mg/ml). In about 60% of patients the prolactin levels were low (2-5 ng/ml). Follicle stimulating hormone, luteinizing hormone, and testosterone were either within normal range or slightly decreased. Despite the above abnormalities, the overall numbers of "normal" spermatozoa per ejaculate were not inferior to those usually present in normospermic specimens, suggesting that factors of presently unknown nature, involved in regulation of both proliferation and spermatogenesis, might be responsible for fertility disorders in these conditions.

Follicle Stimulating Hormone↗
PubMed1978

Unilateral adrenalectomy and pituitary irradiation in the treatment of ACTH-dependent Cushing's disease in children and adolescents.

In four juvenile patients with Cushing's disease, the therapeutic approach used was unilateral adrenalectomy followed by irradiation of the pituitary. The follow-up time of these patients has ranged from 1.5 to 10 years. All four are clinically well. Concentrations of adrenal steroids are within normal limits and they require no additional medication. It is felt that this method gives young patients the chance for normal growth and pubertal development as well as a normal social life, so important in the stressful adolescent years, thus avoiding the handicap incurred by bilateral adrenalectomy and the consequent requirement for continuous substitution therapy.

Adolescent↗
PubMed1976

Protein content of human seminal plasma and spermatozoa in relation to sperm counts.

Protein concentrations of seminal plasma and spermatozoa were estimated in human normospermic, oligospermic and azoospermic semens. The protein content of seminal plasma ranged from 20 to 60 mg per ml semen and was found to be unrelated to sperm counts. Suspended sediments of azoospermic specimens were found to contain on the average 570+/-86 microng protein per ml semen. This value is about four times higher than in severe oligospermic specimens (0.2 X 10(6) -6.5 X 10(6) cells per ml semen). It is suggested that in azoospermic disorders seminiferous tubules secrete abnormally high amounts of proteinacous material which cannot be eliminated by washings. In addition, destruction of immature cells may contribute to increased protein conten in these specimens. Protein determinations in washed spermatozoa showed a negative relationship between the amount of protein calculated per 10(6) cells and original sperm counts. This trend demonstrates an altered protein metabolism in the spermatozoa of oligospermic specimens which might be responsible for fertility incompetence.

Adult↗