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Biomedical subjects

A Leonard

Publications and source records attributed to A Leonard.

At least 55 records · Page 3Linked to original sources
PubMed1986

Seminal vesiculography in chronic bacterial prostatitis.

A total of 15 patients with proved chronic bacterial prostatitis underwent bilateral seminal vesiculography to determine the morphological appearance of the seminal vesicles and the ampulla ducti deferentis in this condition. A pathological condition, such as segmental stenosis or complete shriveling of the seminal vesicles, was obvious in 21 of 24 vesiculograms (87.5 per cent), while malformations of the ampulla were seen in 7 (29.1 per cent). The role of chronic bacterial prostatitis as an important pathogenetic factor in the history of epididymo-orchitis is discussed.

Adult↗
PubMed1986

Characteristics of hazardous material spills from reporting systems in California.

Data on hazardous material releases that occurred between January 1, 1982 and September 30, 1983 in California were obtained from the California Highway Patrol (CHP) and the US Department of Transportation (DOT). The majority of incidents involved highway transport of hazardous materials, although some information was available on air, rail, and stationary facility releases. Vehicle accidents and failure of or damage to the container were the most frequent causes of releases. Proportionately more hazardous materials incidents occurred in early summer than at other times of the year, during weekdays, and daytime hours. The largest proportions of incidents involved the chemical categories of corrosives and fuels. Reported exposures and injuries to response personnel and other people at the scene were relatively few; no fatalities were reported. Few incidents were reported in both data sources, suggesting that the examination of only one data source would yield a gross underestimate of the total number of hazardous materials incidents in California. The lack of available denominator data limits the interpretation of the findings.

Accidents↗
PubMed1985

Dissociation of the receptor for immunoglobulin E in mild detergents.

We previously showed that, in the absence of phospholipids, exposure of the tetrameric receptor for immunoglobulin E to mild detergents dissociates the intact beta chain and two gamma chains from the alpha chains. Having developed a practical method for assaying the dissociation, we have now explored a variety of different detergents, detergent concentrations, temperatures, times, salts, pHs, and other factors that influence the detergent-induced dissociation. Our findings should be useful for optimizing the stability of the receptor and for future studies on recombination of the subunits. The data suggest the following: (1) The critical perturbant is micellar detergent. (2) Unlike solubilization of membranes, where a molar ratio of micellar detergent:lipid of 2 is adequate, dissociation of the receptor is incomplete even at molar ratios of micellar detergent:receptor of greater than 10(5) and may be limited by a reversible component. (3) Detergents that are best for solubilizing membranes are also best for dissociating the receptors. (4) The latter observation and other data implicate bound lipid as stabilizing the receptor. Our findings may be applicable to the study of interactions between membrane proteins in general.

Animals↗
PubMed1985

Effect of an enhanced natural radioactivity on mammal fertility.

Male and female mice of the BALB/c strain were placed on the floor of a hut built at a site of the Permian Basin of Lodève (Southwest France) where the dose rate of gamma radiation amounts to about 10 mrad/h. In previous experiments such high natural radioactivity was shown to induce point mutations in plant material as well as chromosome aberrations in somatic cells of experimental mammals. Controls were kept near the radioactive site under comparable conditions. After the exposure period, the animals were mated in our laboratory, with control mice of the same strain. Due to the high radiosensitivity of mouse oocytes, the fertility of the exposed females was drastically reduced in spite of the fact that the dose received did not exceed 13.8 rad. The fertility of the males exposed to 13 rad, 15 rad or to 45 rad was increased above the control values but was reduced for the animals receiving 63 rad. Analysis of the results show that the differences in fertility are mainly due to a decrease in the number of sterile pairs when males have been exposed to doses upto 45 rad and to an inverse effect when animals received 63 rad. Since histology and weight of the testes suggest that the germ cell population was normal, one has to conclude that the variations in fertility result from physiological effects.

Animals↗
PubMed1985

Mucus structure.

Explore the source record for details and available documents.

Amino Acids↗
PubMed1985

Induction of chromosome aberrations in G0 human lymphocytes by low doses of ionizing radiations of different quality.

Human peripheral blood lymphocytes from two donors were exposed to low doses (0.05 to 2.0 Gy) of gamma rays, X rays, or fast neutrons of different energies. Chromosome aberrations were analyzed in metaphase of first-division cells after a culture time of 45-46 hr. At this time, less than 5% of the cells were found in second division. Different dose-response relationships were fitted to the data by using a maximum likelihood method; best fits for radiation-induced dicentric aberrations were obtained with the linear-quadratic law for all radiations. The linear component of this equation predominated, however, for neutrons in the range of doses studied, and the frequency of dicentrics induced by d(16)+Be neutrons up to 1.0 Gy could also be described by a linear relationship. The relative biological efficiency (RBE) of X rays and d(16)+Be, d(33)+Be, and d(50)+Be neutrons compared to 60Co gamma rays in the low dose range was calculated from the dose-effect relationships for the dicentrics produced. The RBE increased with decreasing neutron dose and with decreasing neutron energy from d(50)+Be to d(16)-+Be neutrons. The limiting RBE at low doses (RBEo) was calculated to be about 1.5 for X rays and 14.0, 6.2, and 4.7 for the d(16)+Be, d(33)+Be, and d(50)+Be neutrons, respectively.

Beryllium↗
PubMed1984

Embryotoxicity and genotoxicity of nickel.

Prenatal effects of nickel result from direct insults to the mammalian embryo as well as from indirect ones through maternal damage. Nickel may upset the hormonal balance of the mother and can impair the development of the preimplantation embryo. The metal can cross the feto-maternal barrier and enter the fetus. In addition to an increase in prenatal and neonatal mortality, nickel can produce different types of malformations in the surviving embryos but its teratogenic action seems to be delayed, probably as a result of retarded transfer via the placenta. No definite conclusions can be reached, at the present time, as to whether the embryotoxicity and fetal toxicity of nickel is eventually related to its mutagenic properties. Nickel alters macromolecular synthesis but no convincing evidence has been provided of its ability to produce gene mutations or structural chromosome aberrations in mammalian cells. Observations on mammalian cells in vitro, confirmed by some data on plant material, suggest that the prenatal effects of nickel could partially be due to the production of certain changes in the mitotic apparatus provoking cellular death at critical times of development.

Abnormalities, Drug-Induced↗
PubMed1982

Ankylosing spondylitis and systemic lupus erythematosus: a rare HLA combination.

The condition of a 43-year-old man fulfilled the strict diagnostic criteria for both ankylosing spondylitis and systemic lupus erythematosus. To our knowledge, this is the fist verified report of the concurrence of these rheumatic diseases. An unusual combination of genetically determined markers seems to have caused an increased risk for the development of both disorders.

Adult↗