Biomedical subjects

B L Sheppard

Publications and source records attributed to B L Sheppard.

57 records · Page 4Linked to original sources

PubMedDate not supplied

Variations in elemental distribution in human spermatozoa.

Morphologically normal spermatozoa from groups of men attending the infertility clinic with normal density and motility had subcellular elemental composition measurements from various parts of the spermatozoa compared with anatomically similar spermatozoa from semen with marked oligo- or asthenozoospermia. In the two groups of semen the mean % value of the elements was similar in the acrosome, nucleus, mid-piece and tail regions excepting sodium and potassium which were significantly lower in the abnormal semen. Although a similar elemental distribution was found in each group the observed trend towards higher total values in the abnormal semen did not reach significance. Highest levels were found in the nuclear and mid-pieces of all spermatozoa suggesting future diagnostic possibilities for such measurements in determining spermatozoal procreative potential.

Elements↗

PubMedDate not supplied

Genome-wide analysis of deoxyribonucleic acid in endometrial cancer using comparative genomic hybridization microarrays.

The aim of this study was to identify amplified oncogenes in endometrial cancer using array-based comparative genomic hybridization (array CGH). Despite its prevalence, the molecular mechanisms of endometrial carcinogenesis are still poorly understood. The selected array CGH allows the simultaneous examination of 58 oncogenes commonly amplified in human cancers and is capable of achieving increased mapping resolution compared with conventional CGH. A subset of 8 specimens from a bank of 60 malignant and normal specimens was selected for array analysis to identify potential genes of interest. TaqMan polymerase chain reaction was carried out on the 60 specimens to examine if aberrations at the genomic level correlated with gene expression and to compare expression in normal and malignant samples. Oncogenes amplified in the endometrial cancers included AR, PIK3CA, MET, HRAS, NRAS, D17S1670, FGFR1, CTSB, RPS6KB1, LAMC2, MYC, PDGFRA, FGF4/FGF3, PAKI, and FGR. Three genes were examined at the messenger RNA level. AR and PIK3CA were higher in normal specimens, and MET was higher in malignant samples, suggesting a role for MET in endometrial cancer. Newer arrays examining more genes and larger sample numbers are necessary to elucidate the carcinogenic pathway in endometrial cancer.

Adenocarcinoma↗

PubMedDate not supplied

Observations on the motility, ultrastructure and elemental composition of human permatozoa incubated with caffeine. II. A time sequence study.

The effect of incubation with caffeine to a final concentration of 6 mM at seven time intervals from 0 to 120 minutes was examined in spermatozoa from two normal fertile semen samples and two infertile asthenozoospermic men. Light microscopic estimation of motility, scanning electron microscopic examination of the surface morphology and scanning transmission determination of subcellular elemental composition was carried out at each stage in comparison with placebo controls (modified Ringer solution). An interaction with incubation appeared necessary for caffeine to energise spermatozoa. This stimulatory effect on motility was more marked in the abnormal subjects although in all four individual response was variable. Surface morphological damage was noted in all experiments but was more pronounced the longer spermatozoa spent incubated with caffeine. Disruption of the sperm head and swelling of the mid-piece were the most characteristic features. Subcellular elemental composition of all six elements was greater in the fertile than in the infertile samples and caffeine exceeded placebo in four of the six, with a significant difference in sulphur levels. Sodium, sulphur and magnesium showed similar patterns of sub-group measurements at each of the seven time points suggesting perhaps a similar time influence mechanism operating for these three elements. The study shows the detrimental effect of incubation with caffeine to be marked and time linked, the shorter the time of incubation exposure with the drug the better. Therefore not only does the damage created make the incubation with caffeine of any semen sample unwise but the time strictures, especially in the asthenozoospermic, show it also to be an impractical method of increasing pregnancy potential in such subjects.

Caffeine↗