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Biomedical subjects

E L Lewis

Publications and source records attributed to E L Lewis.

At least 19 recordsLinked to original sources

Neonatal circumcision techniques.

Neonatal circumcision is most commonly performed using one of three techniques--the Mogen clamp, the Gomco clamp or the Plastibell device. With all three techniques, careful selection and preparation of patients is essential. Informed consent must be obtained from parents or guardians, based on an objective understanding of the medical and social implications of circumcision, including potential complications from the procedure. Measures for creating an aseptic field, anesthesia and positioning of the infant do not vary with the technique selected. Both the Mogen and Gomco clamps protect the glans while producing crush injury to the prepuce, which is then surgically removed. The Plastibell device induces necrotic tissue, which is sloughed off, along with the plastic shield, within a week or so. Although complications from neonatal circumcision are rare, hemorrhage, local infection, sepsis, meatal ulceration and poor cosmetic results have been reported.

Circumcision, Male

Differential in vitro inhibition of feline enteric coronavirus and feline infectious peritonitis virus by actinomycin D.

The growth of feline enteric coronavirus strain 79-1683 in whole feline embryo cells was inhibited by the presence of 1 microgram/ml of actinomycin D in the culture fluid. No virus-specific mRNAs could be detected in such cultures and yields of infectious virus were depressed by > 99%. By contrast, the antigenically related feline infectious peritonitis virus strain 79-1146 was unaffected by the presence of actinomycin D, indicating a fundamental difference between the two feline coronavirus strains in their requirements for host-encoded function(s).

Animals

Semen quality in varicocele patients is characterized by tapered sperm cells.

We used a retrospective case-control study design to compare sperm morphology in 50 varicocele patients and 50 patients with idiopathic infertility. Cases and controls were matched for the percentage of motile sperm and total sperm number per ejaculate. Varicocele patients had significantly more tapered sperm (36% +/- 3% versus 15% +/- 2%) and significantly fewer oval sperm (41% +/- 3% versus 47% +/- 2%). There was no significant difference between cases and controls in any other morphological type.

Case-Control Studies

Behaviour of a replicating mitochondrial DNA sequence from Aspergillus amstelodami in Saccharomyces cerevisiae and Aspergillus nidulans.

An amplified sequence of mitochondrial DNA from a ragged (rgd) mutant of Aspergillus amstelodami has been shown to exist in multimeric circular form, suggesting that it is excised from the genome and can exist independently of it. This sequence has replicative (ARS) activity in Saccharomyces cerevisiae, and a subfragment responsible for this activity has been identified and sequenced. A homologous sequence from Aspergillus nidulans mtDNA also has ARS activity in S. cerevisiae. Both A. amstelodami and A. nidulans ARS elements have been incorporated into the integrative transformation vector pDJB1 and the derived vectors used to transform A. nidulans. Inclusion of the A. nidulans ARS element enhanced the transformation frequency 5-fold relative to pDJB1. No increase in transformation frequency was evident with the ARS element from A. amstelodami. The stability of transformants was variable but in comparison to pDJB1, ARS-containing plasmids were mitotically unstable in A. nidulans. Although plasmid DNAs could be rescued in Escherichia coli from undigested transformant DNA, no freely replicating plasmids were detected by Southern hybridisation.

Aspergillus

The relationship of circulating antisperm antibodies to sperm surface antibodies in infertile men.

The correlation between the amount and location of antisperm antibody binding to the sperm surface and the level measured in the serum has not been previously reported. Hence, the value and limitations of screening blood sera from men with suspected immunologic infertility are not currently known. In this study 70 paired sera and semen samples were assayed by the immunobead test (IBT). A screening protocol for blood sera was constructed to be 100% sensitive for detecting semen specimens with 20% or more of sperm binding IgG or IgA immunobeads. The specificity of this screening protocol was determined to be 79%. Serum IgA was not a good predictor of IgA on the sperm surface. The true positive predictive rate for antisperm antibodies on the sperm surface using circulating antisperm antibodies as a screening assay was estimated to be as low as 35%. There was little correlation between the site of immunobead binding following passive antibody transfer from patients' sera to donor sperm and the site of naturally occurring antibodies on the patients' sperm surface. Although direct assessment of antibodies on the sperm surface is preferred, these data suggest that serum IgG alone can be used as a sensitive screening assay for antisperm antibodies in men. A positive screen dictates that a direct assay on semen should be performed.

Antibodies

Prospective surveillance of semen quality in the workplace.

We performed a prospective surveillance of semen quality among workers in the plant where 1,2-dibromo-3-chloropropane was first recognized as an occupational cause of impaired semen quality and of infertility. All male employees of the Agricultural Chemical Division were required to participate. Ninety-seven workers (92% participation) provided 258 semen samples over the 4 years of the program. Most samples were analyzed at the plant with a mini-laboratory designed for the study. Motility and shape measures were made objectively. Sixty-six subjects (68%) were non-azoospermic. Generalized multiple regression showed no significant predictors for any response, with the exception of the motility measures, which were reduced with longer times between ejaculation and assay. Between- and within-person standard deviations and correlations were calculated. Comparison of this population with fertile artificial insemination donors (16 men, 498 ejaculates) revealed generally higher ejaculate-to-ejaculate standard deviations in the worker samples. This is probably due to less well controlled conditions of sperm collection in the workplace setting. For cross-sectional studies, one ejaculate per worker is recommended as sufficient; for estimating an individual worker's mean, even three ejaculates may not provide enough precision.

Environmental Exposure

Antisperm antibodies bind with different patterns to sperm of different men.

Immunologic infertility is an important area of current clinical research. The immunobead test is a laboratory method that identifies the classes of antisperm antibodies and their binding sites on the sperm surface. In this study we have investigated the variability in the pattern of antibody binding to spermatozoa after passive transfer from blood serum. Serum from a single donor containing antisperm antibodies of the IgG class was used in all experiments. The spermatozoa from 27 semen donors were found to differ significantly in the degree and location of immunobead binding after exposure to this serum. There was substantial day-to-day variability in the results for individual semen donors and the overall variability in test results was significantly greater when a number of semen donors was used rather than a single donor. These data suggest that details of antisperm antibody binding after passive transfer from body fluids may depend on the sperm donor. The design of research studies involving antibody transfer must take this source of variability into account.

Adult

Measurement of human testicular consistency by tonometry.

A tonometer was used for objective assessment of testicular consistency in a group of 83 men. Testicular measurements in three dimensions were also obtained using calipers. The testicular tonometry value was found to be significantly correlated with the clinical impression of testicular consistency and with testicular size. The testicular tonometry value for the right testicle was significantly larger than the tonometry value for the left testicle in all men except those with azoospermia. The difference in tonometry values between the right and left testicles was most significant in the group of men with left varicocele. The men with varicoceles also had left testicles which were significantly smaller than the paired right testicle in two of three dimensions. In the group with varicocele there was a significant positive correlation between the tonometry value and sperm concentration in the semen. In men with no history of varicocele there was a significant positive correlation between the tonometry value and the percentage of oval sperm.

Humans

SAMP lyase and AMP deaminase activity in rat parenchymal and kupffer cells in hepatocarcinogenesis.

SAMP lyase and AMP deaminase were determined in parenchymal and kupffer cells of rats fed either basal or carcinogen-enriched diets. Results were calculated on a U/mg protein and U/cell basis. Data indicated that although deaminase increased 1 1/2 to 2-fold in parenchymal cells on a U/mg protein and U/cell basis from rats fed carcinogen-enriched diets there was a greater increase in U/mg protein. In contrast, little to no increase was seen in kupffer cells. SAMP lyase, however, depicted a smaller increase in parenchymal cells of carcinogen-enriched diet fed rats, but a 4- to 5-fold elevation in kupffer cells regardless of whether the data were expressed in U/mg protein or U/cell. These data indicate that increased activity of AMP deaminase may be a result of resistance to degradation in parenchymal cells, whereas SAMP lyase elevations in kupffer cells may reflect an increase in enzyme concentration.

AMP Deaminase

Human sperm function in the ejaculate following vasectomy.

Semen specimens were obtained for analysis from nine men immediately before vasectomy and 3 days following the vasectomy procedure. After vasectomy there was a significant decrease in seminal sperm concentration, percentage of sperm motility, and mean swimming speed. In seven of nine cases the spermatozoa did not survive overnight incubation in capacitation media, and in no case was penetration of zonafree hamster oocytes observed 3 days after vasectomy.

Animals

Agenesis of ureter.

A case is reported of congenital absence of left ureter with the left renal pelvis presenting as a diverticulum of the bladder. This occurred in a patient with at least eight other major congenital anomalies.

Abnormalities, Multiple

Simultaneous assessment of human sperm motility and morphology by videomicrography.

Videotapes were analyzed to assess sperm motility and morphology in the semen of 5 fertile donors and 20 infertile patients. The slow motion playback control of the video recorder allowed simultaneous assessment of the motility and morphology of individual sperm cells. Similar values were obtained with this method for abnormal morphology more often were immotile or weakly motile than were the normal sperm in the same ejaculates. Normal oval sperm in the semen of infertile men were less likely to be motile and tended to swim more slowly than did morphologically normal sperm in the semen of fertile men.

Adult