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Biomedical subjects

R Singer

Publications and source records attributed to R Singer.

At least 109 records · Page 6Linked to original sources
PubMed1982

Pleistocene Macaca from Hoxne, Suffolk, England.

Pleistocene macaque remains are uncommon in Great Britain. In addition to three specimens previously known from three sites, four teeth from Hoxne, Suffolk are recorded here. Closely resembling teeth of modern Macaca sylvanus (Barbary ape), they were recovered from a Middle Pleistocene stratum containing stone artifacts (including handaxes) and fauna including cold-climate lemmings.

Animals↗
PubMed1982

Vitamin A and beta-carotene content of seminal fluid and sperm of normospermic and oligozoospermic men.

Beta-carotene and vitamin A were estimated in 125 specimens of human seminal fluid and spermatozoa. In 72 of the specimens triiodothyronine, tetraiodothyronine, and T4-binding globulin were also determined. Vitamin A in seminal fluid increased from 10.4+/-l.8 microgram (SE) in severe oligozoospermia up to 19.1+/-2.5 microgram/100ml in specimens with high sperm densities. In spermatozoa, however, there was a trend for a decrease in vitamin content from 2.1+/-0.8 to 0.2 +/-0.07 microgram/108. In the majority of cases beta-carotene was undetectable and, when present, the levels were much lower than those of vitamin A. The amounts of triiodothyronine and tetraiodothyronine in seminal fluid were 0.19+/-0.03 ng/ml and 1.1+/-0.18 microgram/100ml, respectively. No correlation was found between levels of both hormones and quality of seminal fluid. T4-binding globulin was either very low or undetectable.

Alpha-Globulins↗
PubMed1982

Inhibition and enhancement of macrophage migration in the presence of lymphocytes and seminal fluid of men with fertility disorders.

Macrophage migration inhibition factor (MIF) towards autologous seminal fluid was studied in 29 infertile men, 16 of whom were also examined towards normal seminal fluid. In 10 patients, inhibition of macrophage migration was observed in the presence of 50 microgram of protein of autologous semen sonicates. Nine patients had enhanced macrophage migration in the presence of 5 microgram protein. Macrophage enhancement was more antigen dependent than the migration inhibition. In all patients seminal abnormalities were observed, being milder in the patients whose lymphocytes enhanced macrophage migration.

Humans↗
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

Body height, weight, and skeletal maturation in Hottentot (Khoikhoi) children.

Growth of body height and weight and skeletal maturation are discussed, based on 49 male and 61 female Hottentot children aged 3 to 17 years from Warmbad, Namibia (South West Africa) and 124 boys and 113 girls aged 1 to 21 years of related populations, the Rehoboth Basters of Namibia and Cape Coloreds from Cape Town, South Africa. The related populations are taller and heavier than the Hottentots, and have almost the same body height as American blacks and whites at least after the age of 18 years. In the Hottentots and Rehoboth Basters, the mean TW2 skeletal age is always less than the British standard by one or two years in both sexes. In general, the Rehoboth Basters have a skeletal age that is intermediate between Hottentot and British children. In both Hottentots and Rehoboth Basters, the increase in body height shows a linear relation to the skeletal age, and the regression curves are almost parallel in both sexes. The differences in body height and weight between the Hottentots and Rehoboth Basters become greater after the skeletal ages of 15 years for boys and 13 years for girls.

Adolescent↗
PubMed1981

Intravenous fluorescein for evaluating the dusky nipple-areola during reduction mammaplasty.

The intravenous fluorescein test is a useful, safe adjunct in assessing the breast skin, as well as the nipple-areola complex, in reduction mammaplasties. If all the tissue fluoresces, one can safely assume that the area will go on to remain viable. If the nipple-areola does not fluoresce, the breast should be reexplored. Anything that subsequently fluoresces generally remains viable. If the nipple-areola remains nonfluorescent, then it should be converted to a full-thickness graft.

Breast↗
PubMed1981

[Results of primary antineoplastic chemotherapy in advanced keratinizing squamous epithelial carcinomas of the head and neck region].

From 1975 to 1980 121 patients with advanced carcinoma of oral cavity, oropharynx and hypopharynx were treated by a primary systemic chemotherapy with vincristine/MTX-folinic acid/intrinsic factor/thymidine--bleomycin/inosine. A complete remission and partial remission of more than 50% was obtained in 81% of tumors of oral cavity, while the remission of the carcinoma of oropharynx with 73% and of hypopharynx with 50% is caused by a lower sensitivity rate of the less keratinizing tumors. The chemotherapeutic results after preceding operation and radiation underline by a lower rate of remissions the only palliative aspect and the necessity of antineoplastic chemotherapy to the first step before operation and radiation. The results of remission followed by primary antineoplastic chemotherapy bring better conditions for the operation and supplementary radiotherapy: the high number of complete remissions allows a tender operation in the field of the former carcinoma with histological security, the partial remission of more than 50% guarantees a more exact determination of the border of tumor and of the distance of security by reduction and demarcation of the tumor, its devitalisation brought by keratinisation, the stop of invasive growth and by the increase of the surrounding connective tissue. Because of the short remission of metastasis of lymph nodes a radical neck dissection and sanitation of the floor of the mouth is an oncological necessity in case of metastasis. The estimated median survival time was 21 months in advanced carcinomata of oral cavity and as for keratinizing squamous cell carcinoma of oropharynx. A lower mean survival period will be expected by the less keratinizing squamous cell carcinomata of the oro- and hypopharynx with 11 or 10 months. Fixed lymph nodes and distant metatasis bring a decrease of the estimated median survival time with a statistical significance.

Adult↗
PubMed1980

Lead exposure and behavioral changes: comparisons of four occupational groups with different levels of lead absorption.

The association between lead absorption and objective psychological performance tests in five groups with different levels of lead absorption was studied in the following groups: (1) a control, non-lead-exposed group; (2) cable splicers, (3) cable manufactures, and (4) secondary lead smelter workers. The following performance tests were used: Block Design, Digit Symbol, and Embedded Figures. Age-corrected performance test scores and the average of three test scores (INDEX) were used throughout. A significant association between performance tests scores and increased lead absorption was found. Zinc protoporphyrin level was a more "powerful" (in the statistical sense) indicator of lead-induced CNS effects than blood lead levels. This study provides additional evidence that neurotoxic effects associated with occupational exposure to lead can be demonstrated by means of performance tests. It has been known and widely accepted that increased lead absorption is associated with "non-specific" subjective symptoms: tiredness, sleep disturbance, irritability, etc. Psychometric techniques (including an appropriate statistical analysis strategy) are highly sensitive for the early detection of CNS neurotoxicity, such as metal toxicity. Moreover, even in lead-exposed but asymptomatic individuals, a significant correlation (negative) between test scores and levels of lead absorption could be detected. It is concluded that workers exposed to lead at levels considered "safe" might be at risk of developing brain dysfunction with long term exposure.

Humans↗
PubMed1980

Brachymesophalangia V in Hottentot and "Cape Colored" children in Namibia (South West Africa) and South Africa.

In order to determine the incidence of Brachymesophalangia V, an inspectional and metrical analysis was made of radiographs of 67 Nama-speaking Hottentots aged 2 to 17.5 years, and 210 Rehoboth Basters (in Namibia) and Cape Colored children (near Cape Town) aged 1.5 to 21 years. None of the children displayed cone-shaped epiphysis or early union, and none showed Brachymesophalangia V. It was confirmed that the incidence of Brachymesophalangia V is considerably higher in Mongoloid populations than in Caucasoid or Negroid groups, including Hottentots.

Adolescent↗
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↗