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Biomedical subjects

D J Anderson

Publications and source records attributed to D J Anderson.

At least 307 records · Page 17Linked to original sources
PubMed1990

A rare intradural tumor simulating spondylolisthetic radiculopathy.

Intradural tumors can produce nerve root symptoms similar to those caused by extradural compressive processes. In a 48-year-old man, the preoperative evaluation was spondylolisthetic radiculopathy; however, a lumbar myelogram prior to surgery revealed an unsuspected intradural tumor. The patient's symptoms resolved after removal of the tumor without treatment of the spondylolisthesis. When planning surgical treatment for any extradural process, intradural abnormalities must be ruled out by appropriate preoperative studies. Myelography and magnetic resonance imaging are now standard methods of evaluating the dural contents.

Diagnosis, Differential↗
PubMed1990

Asymptomatic cervicovaginal leukocytosis in infertile women.

Cervicovaginal cells were obtained from 114 women undergoing intrauterine insemination and 21 women undergoing donor insemination. Monoclonal antibodies were used to identify leukocyte subpopulations in women with nonepithelial cell counts greater than 2 X 10(5) (termed asymptomatic cervicovaginal leukocytosis). Leukocyte counts exceeding this number were not found in any of the women undergoing donor insemination; however, greater than 2 X 10(5) leukocytes were detected in 22% of the infertile women. Granulocytes predominated; lymphocytes and macrophages were detected in only 8 of 114 samples. Women with cervical factor infertility had a significantly higher incidence of asymptomatic cervicovaginal leukocytosis than women with either male factor or unexplained infertility. These data suggest that cervicovaginal leukocytes may play a role in cervical factor infertility since soluble products of activated leukocytes are known to adversely affect reproduction.

Cervix Uteri↗
PubMed1990

Leukocytospermia is associated with poor semen quality.

Semen samples from 179 infertility patients were analyzed for type and number of white blood cells (WBC) by a combination of immunologic techniques. Forty-one (23%) had more than 10(6) WBC/mL semen (leukocytospermia). Semen parameters in patients with less than 10(6) WBC/mL were similar to those of 15 fertile donors. In contrast, the leukocytospermic group had significant reductions in total sperm number, percent sperm motility, sperm velocity, motility index, and total number of motile sperm. Patients with high concentrations of monocytes/macrophages (greater than 5 X 10(5)/mL; n = 27) had significantly reduced ejaculate volume; patients with high numbers of T lymphocytes (greater than 10(5)/mL; n = 19) had a significant reduction in sperm velocity; and patients with high levels of granulocyte elastase in semen (greater than 1,000 ng/mL; n = 26) had significant reductions in ejaculate volume, total sperm number, and total motile sperm number. There was no correlation between the presence of antisperm antibodies and leukocytospermia. Our data suggest that leukocytospermia may occur frequently in male infertility patients and show that elevated levels of WBC in semen are associated with poor semen quality. This provides further rationale for white blood cell testing in semen of male infertility patients, since antibiotic or anti-inflammatory therapy may be helpful in appropriately selected cases.

Cell Degranulation↗
PubMed1989

The effects of lymphokines and monokines on human sperm fertilizing ability in the zona-free hamster egg penetration test.

Antisperm cell-mediated immunity has been associated with infertility in men and women. The purpose of this study was to determine whether the products of activated lymphocytes and macrophages (lymphokines and monokines) affect the fertilizing ability of human spermatozoa in the zona-free hamster egg penetration test. Of a panel of six different purified cytokines tested, the lymphokine gamma-interferon and the monokine tumor necrosis factor significantly affected the ability of human sperm to penetrate hamster eggs. An inhibitory effect was observed when motile sperm were harvested for use in the assay by a swim-up technique after overnight incubation in low amounts of these cytokines and also when the factors were added to the cultures at the time sperm were introduced to the eggs. These data contribute further evidence that soluble factors produced by activated lymphocytes and macrophages in reproductive tissues could be significant mediators of immunologic infertility.

Animals↗
PubMed1989

Lymphocyte activity in the presence of peritoneal fluid from fertile women and infertile women with and without endometriosis.

Peritoneal fluid from women with endometriosis, unexplained infertility, and fertile controls were compared to one another and to normal human serum for effects on lymphocyte proliferation in vitro. Peritoneal fluid samples were also assayed for both interleukin-1 and interleukin-2. All peritoneal fluid samples significantly enhanced lymphocyte proliferation in both mitogen-stimulated and unstimulated cultures compared with serum controls. Mitogen-induced leukocyte proliferation was higher in the presence of peritoneal fluid from women with endometriosis compared with other samples. Five out of 23 samples from endometriosis patients contained elevated levels of interleukin-1 and three out of 23 contained elevated levels of interleukin-2. Six out of eight peritoneal fluid samples from unexplained infertility patients also had elevated levels of interleukin-2; samples from fertile women did not contain elevated levels of either cytokine. Our data indicate that peritoneal fluid from women with endometriosis and unexplained infertility support the activation and proliferation of lymphocytes. Leukocyte products may locally affect the progression of disease and fertility.

Ascitic Fluid↗
PubMed1989

Antiproliferative effect of gossypol and its optical isomers on human reproductive cancer cell lines.

The antiproliferative effect of gossypol and its optical isomers on various human cell lines of reproductive and nonreproductive tissue origin was studied. Various reproductive cancer cell lines of ovarian, gestational, and testicular origin were highly sensitive (IC50 values of 0.86-1.98) to gossypol. The antiproliferative action of gossypol was not restricted to reproductive cancers, as non-reproductive cancer cell lines were also equally sensitive (IC50 values of 0.69-3.55). In addition, actively proliferating untransformed cells such as fibroblasts and PHA-activated lymphocytes were also sensitive (IC50 values of 0.87-2.51). (-)-Gossypol was 3.6-12.4 times more potent than (+)-gossypol and 1.48-2.65 times more potent than (+/-)-gossypol. The most sensitive indicator of gossypol action was a decrease in DNA synthesis followed by inhibition of protein synthesis and uptake of rhodamine-123 by mitochondria as tested in an ovarian cancer cell line (OVCA 433) and a fibroblast line (Hs27). These results indicate that gossypol possesses a general nonselective antiproliferative action toward human cells in vitro. Further, the pharmacologic activity of gossypol as an antiproliferative agent is primarily attributable to its (-) isomer, which is also the active isomer as a contraceptive.

Antineoplastic Agents↗
PubMed1989

Cellular 'neoteny': a possible developmental basis for chromaffin cell plasticity.

Adrenal medullary chromaffin cells, SIF cells and sympathetic neurons are derived from the sympatho-adrenal sublineage of the neural crest, and represent a range of cellular phenotypes extending from endocrine to neuronal. It is suggested here that these cell types may represent different stages of developmental 'arrest' along a linear pathway whose endpoint is a cholinergic sympathetic neuron. This model explains the 'transdifferentiation' of mature cells seen in this system as simply a delayed realization of transitions that normally occur between these stages during development. Such a 'linear model' of phenotypic diversification may be applicable to other developing systems that generate closely related but distinct cell types.

Adrenal Medulla↗
PubMed1989

Distribution of planktonic bacteria capable of degrading sodium dodecyl sulphate (SDS) in a polluted South Wales river.

The temporal and geographical distributions of planktonic bacteria, and their ability to degrade sodium dodecyl sulphate (SDS) (AS(+) phenotype), in a polluted South Wales river, is reported for five sites source to estuary sampled during a one-year period. The annual mean prevalence of AS(+) isolates at all sites was 8.1-16.0% of the total number of isolates, and these values were not altered by including SDS in culture media. Although the proportion of AS(+) isolates in clean water at the source was not significantly different to that of polluted sites, the AS(+) cell density was lower at the source because of its lower overall numbers. The percentage of AS(+) isolates in estuarine water was higher than at the three polluted mid-river sites, but when cell numbers were taken into account, the AS(+) cell density was the same at all polluted sites including the estuary. There was no correlation between percentage of AS(+) and either BOD or oxygen concentration, but AS(+) isolates were significantly more prevalent at the end of summer. Of the AS(+) isolates, more than half contained constitute alkysulphate enzymes, the remainder being induced or repressed by SDS; the relative proportions of enzyme regulatory type did not vary significant between sites or at different sampling times.

Journal Article↗
PubMed1989

Role of glucocorticoids in the chromaffin-neuron developmental decision.

Chromaffin cells and sympathetic neurons develop from a common neural crest-derived progenitor cell. The developmental fate of this cell differs depending upon whether it migrates to the sympathetic ganglion or to the adrenal gland primordium, suggesting that local environmental signals control its differentiation. Glucocorticoid (GC) is a good candidate for an important adrenal environmental signal. These steroids are known to regulate PNMT, an adrenal-specific enzyme. However, in vivo observations suggest that the adrenal microenvironment influences the phenotype of sympatho-adrenal progenitor cells as early as E14.5, 2 days before PNMT is first expressed by developing chromaffin cells. Using cDNA probes, we find that GC receptor mRNA can be detected in the embryonic adrenal at least one full day before the initial appearance of PNMT mRNA. This observation is compatible with the idea that the apparent early influence of the adrenal microenvironment reflects the action of GC on progenitors which have migrated into this environment. In support of this, we show that similar influences can be exerted by GC on PC12 cells, which contain GC receptor mRNA but do not express or induce PNMT mRNA. Taken together, these data suggest that other factors in addition to the presence of the GC receptor may be necessary for the developmental appearance of PNMT expression.

Adrenal Medulla↗
PubMed1989

Chromatin structure as a molecular marker of cell lineage and developmental potential in neural crest-derived chromaffin cells.

Adrenal medullary chromaffin cells have the capacity to transdifferentiate into sympathetic neurons. We show here that SCG10, a neural-specific gene that is induced during this transdifferentiation, is maintained in mature chromaffin cells in a potentially active chromatin conformation marked by two DNAase I hypersensitive sites (HSS). A low level of transcription is associated with this conformation. The HSS are also present in neurons expressing high levels of SCG10, but not in nonneuronal cells. Experiments using transgenic mice suggest that these HSS can in principle form in any cell type expressing the gene, but that a cis-repression mechanism normally prevents their assembly in nonneuronal cells. We suggest that the SCG10 HSS may represent a molecular marker of the lineage and phenotypic plasticity of chromaffin cells.

Adrenal Glands↗
PubMed1989

Trophoblast/leukocyte-common antigen is expressed by human testicular germ cells and appears on the surface of acrosome-reacted sperm.

The murine monoclonal antibody H316 reacts with a cell-surface antigen of human trophoblast, leukocytes, certain epithelia, and several malignant cell types. We have found that the H316 antibody also recognizes an antigen synthesized by pre- and post-meiotic human testicular germ cells and is expressed in the acrosomal region of methanol-fixed testicular, epididymal, and ejaculated sperm. The antigen is poorly expressed on the surface of fresh ejaculated motile sperm, but is detectable on most viable sperm after a 6-h incubation in medium containing human serum albumin (HSA), or 60-min incubation with the calcium ionophore A23187 (both treatments induce sperm acrosomal changes termed capacitation and acrosome reaction). We found that antigen recognized by H316 is immunoprecipitated as a single, broad 50 kDa band from radiolabeled ionophore-treated sperm extracts and that preincubation of HSA-capacitated sperm with this antibody causes a moderate, but significant, inhibition of hamster egg penetration. These data indicate that the antigen recognized by the H316 monoclonal antibody is synthesized by testicular germ cells and is surface-expressed on capacitated/acrosome-reacted sperm populations. Its potential as a human sperm acrosome reaction marker, and possible biological role in sperm-egg or sperm-lymphocyte interactions, warrants further investigation.

Antibodies, Monoclonal↗
PubMed1989

Ultrasonic measurement of lumbar canal diameter: a screening tool for low back disorders?

Preventive screening measures for low back pain are limited. Despite considerable evidence that anatomic narrowing of the lumbar spinal canal is a risk factor for specific back problems, difficulty in measuring the canal without unacceptable radiation exposure, cost, or discomfort has limited the assessment of its clinical significance. Using ultrasound to measure the lumbar canal is relatively easy to do, and provides accurate values. In this paper we review the reports on this use of ultrasound, including our own experience in a case control study, and discuss the potential use of ultrasonic measurement as a screening tool to identify narrow lumbar canals.

Back Pain↗
PubMed1989

Batch-fabricated thin-film electrodes for stimulation of the central auditory system.

Silicon micromachining and thin-film technology have been employed to fabricate iridium stimulating arrays which can be used to excite discrete volumes of the central nervous system. Silicon multichannel probes with thicknesses ranging from 1 to 40 microns and arbitrary two-dimensional shapes can be fabricated using a high-yield, circuit-compatible process. Iridium stimulating sites are shown to have similar characteristics to iridium wire electrodes. Accelerated pulse testing with over 8 million 100 microA biphasic current pulses on 8000 microns 2 sites has demonstrated the long-term stability of iridium and activated iridium sites. In vivo tests have been performed in the central auditory pathways to demonstrate neural activation using the devices. These tests show a selective activation both as a function of site separation and site size.

Animals↗