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Biomedical subjects

L W Wilson

Publications and source records attributed to L W Wilson.

11 recordsLinked to original sources
PubMed1997

Acute testicular ischemia results in germ cell-specific apoptosis in the rat.

Testis torsion-induced aspermatogenesis is not necessarily due to permanent loss of blood flow nor to dysfunctional Leydig cells or Sertoli cells. This investigation was undertaken to gain further insight into the mechanism underlying torsion-induced germ cell loss. Male rats were subjected to 1-h or 2-h ischemia-inducing torsion, and testes were examined at either 1, 2, 4, 24, or 48 h after torsion, depending on the study. Testes were examined for evidence of 1) in situ apoptosis by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labeling (TUNEL) technique, 2) apoptosis by the DNA "laddering" technique, 3) leukocyte margination and diapedesis in testicular vessels by immunocytochemical and histological techniques, and 4) testicular lipid peroxidation by the thiobarbituric acid reactive substances assay. The first TUNEL evidence for torsion-induced apoptosis was at 4 h after repair of 1-h torsion. Induction of apoptosis was confirmed by the electrophoretic laddering of DNA fragments. It was hypothesized that apoptosis was induced by reactive oxygen species arising from reperfusing leukocytes. A significant increase in both leukocyte margination and diapedesis occurred 4 h after torsion repair as did a significant increase in intratesticular lipid peroxidation products. These events were contemporaneous with the first appearance of apoptosis and consistent with the hypothesis that post-torsion, germ cell-specific apoptosis is induced by reactive oxygen species.

Animals↗
PubMed1995

PSA immunoreactivity detected in LNCaP cell medium, breast tumor cytosol, and female serum.

We made an effort to identify a reliable source for obtaining large quantities of both free (PSA) and PSA-ACT complex for the preparation of the calibrator for the PSA assay. Using size exclusion chromatography, we found both free PSA and PSA-ACT complex in the conditioned cell medium of the LNCaP cell line, which was derived from a human metastatic adenocarcinoma of the prostate. An assay specific for PSA-ACT reacted only with the PSA-ACT complex from cells grown in serum-free medium, and not with the complex from the cell medium grown in 10% calf serum. We also found both free PSA and PSA-ACT complex in 15% of cytosols prepared from breast tumor tissues; the cytosol PSA concentrations ranged from 0.1 to 110 ng/ml. No correlation was found between cytosol PSA and concentrations of estrogen receptor, progestin receptor, epidermal growth factor receptor, cathepsin D, or the ectodomain of c-erbB-2 protein. Based on chromatographic characterizations and the slope of their dose-response curves, it appears that both free PSA and PSA-ACT complex found in the cytosols are similar to PSA complex from the cell medium and the serum of prostate cancer patients. Ectopic PSA was also detected in pooled sera from patients with breast, ovarian, pancreatic, and colon carcinoma. The PSA concentrations in these serum pools increased with the level of their dominant tumor marker. In any event, the LNCaP cell medium appears to be a reliable source for obtaining both free and ACT-complexed PSA of human tumor origin for the preparation of PSA assay calibrators.

Breast Neoplasms↗
PubMed1995

Development of a microplate ELISA for free PSA and PSA-ACT complex in serum.

An ELISA on microplate was established for the total serum PSA. We selected the monoclonal antibody for the assay from commercial sources making certain that it reacted with both free PSA and PSA-alpha 1-antichymotrypsin (PSA-ACT) complex from human serum with similar affinity (so-called "equimolar"). We also chose a test format with polyclonal anti-PSA antibodies coated on the well and monoclonal anti-PSA antibodies for quantification to gain higher test sensitivity. Two different sample volumes from each specimen, 5 and 50 microliters, were used for the assay in order not only to further increase test sensitivity and improve precision at both low and highly elevated PSA concentrations, but also to widen the assay concentration range (0-500 ng total PSA per ml). Using two sample volumes also reduces any hook effect and shortens the turn-around time because repeated determinations are usually required when specimens contain highly elevated PSA concentrations. The use of pooled sera containing approximately 95% PSA-ACT complex and 5% free PSA as a calibrator allows for a close matching of the calibrator with serum specimens in immunoreactivity and PSA composition. Moreover, our assay shows no hook effect up to 15,000 ng/ml. The within-day precision (% CV) in the critical concentration range of 4-12 ng/mL is approximately 5%. The PSA values obtained from this assay correlate well with that of the Hybritech kit (gamma = 0.998, slope equals to 1.033), indicating that this kit can replace the Hybritech Tandem E PSA kit for serum PSA determination in clinical laboratories.

Antibodies, Monoclonal↗
PubMed1995

High-performance cycle counting.

This article describes how to perform cycle counting to measure inventory record accuracy and to find errors in inventory records--and to fix the causes of those errors. Cycle counting is an efficient way of accomplishing these two objectives. The article describes various inventory counting methods and their advantages and disadvantages.

Efficiency, Organizational↗
PubMed1989

The type I insulin-like growth factor receptor is a motility receptor in human melanoma cells.

Insulin-like growth factors I and II (IGF-I and II) and insulin are chemotactic agents for the human melanoma cell line A2058. As shown in this report, the motility receptor mediating this response is the heterodimeric type I IGF receptor. These three factors are able to compete with 125I-labeled IGF-I for binding to the cell surface with IC50 values equal to approximately 2 (IGF-I), approximately 150 (IGF-II), and approximately 300 nM (insulin). Cross-linking of 125I-IGF-I to the cell surface with disuccinimidyl suberate followed by analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography reveals a 130-kDa protein (reduced) consistent with the alpha component of a type I receptor and a 38-kDa protein which does not bind insulin, and thus could be another IGF-I cell surface binding protein. The anti-IGF-I receptor monoclonal antibody (alpha IR-3) also competes with labeled IGF-I in binding experiments. In contrast, a control monoclonal antibody, matched to alpha IR-3 with respect to IgG subclass, has no significant effect on IGF-I binding. While alpha IR-3 inhibits the motility induced by IGF-I, IGF-II, and insulin, pertussis toxin (0.01-1.0 micrograms/ml) has no significant effect on the motility induced by the insulin-like growth factors or insulin on this cell line. Therefore, the type I IGF receptor appears to mediate a highly potent pertussis toxin-insensitive motility response to IGF-I, IGF-II, and insulin. In contrast, motility induced by the autocrine motility factor, a cytokine produced by the A2058 cells, is not affected by alpha IR-3 but is extremely sensitive to pertussis toxin. When mixtures of autocrine motility factor and IGF-I are employed to induce chemotaxis, the resulting motility is greater than that induced by either agent alone. These data indicate that motility in this melanoma cell line can be initiated through multiple receptors that stimulate the cells by separate transduction pathways. This capability to respond to multiple stimuli could enhance the metastatic potential.

Antibodies↗
PubMed1988

Progesterone receptor: stability studies and correlation between steroid binding assay and enzyme immunoassay.

We evaluated and compared Abbott Laboratories' newly developed enzyme immunoassay (EIA) for measuring progesterone receptors (PgR) with that of DuPont's steroid-binding assay (SBA). We also used both methods to study the stability of PgR under various conditions. THere were excellent correlations for all 59 cytosols compared (r = 0.94) and for the 44 cytosols containing PgR greater than 10 fmol per milligram of protein (r = 0.93), but the correlation for cytosols containing less than 10 fmol of PgR per milligram was poor. We found PgR to be more stable as assayed by EIA than by SBA. The biological half-lives of PgR at 30, 4, and -60 degrees C were approximately 3 h, 6 days, and 19 days, respectively. The effect of molybdate on PgR is complex. Its presence during tissue homogenization leads to analytical recovery of more PgR and may stabilize PgR during storage. Its presence during enzyme immunoassay is less critical. Unlike estrogen receptor, PgR is not protected by its ligand, R5020.

Half-Life↗
PubMedDate not supplied

The elderly and pneumonia. Prevention and management.

Pneumonia is as significant concern for caregivers of the elderly, often because of the obscure manifestation of the disease and reports of increasing mortality. Key diagnostic criteria, prevention measures, and management strategies are reviewed for the home healthcare nurse.

Aged↗
PubMedDate not supplied

Conversion of a qualitative screening test to a quantitative measurement of urinary cystine and homocystine.

Qualitative urinary screening procedures were converted to quantitative methods for urinary cystine and homocystine based on the reactions between these amino acids and cyanide-nitroprusside reagents. Cystine and homocystine are quantified by the measurement of absorbances at 521 and 524 nm, respectively. Cyanide-nitroprusside reacts with both cystine and homocystine. However, in the presence of silver nitrate, only homocystine reacts to produce a magenta color. Following the cyanide-nitroprusside reaction, absorbance must be read within three minutes for cystine and immediately for homocystine. The stability of the absorption spectra has no apparent effect on these quantitative assays. Amino acid concentrations are expressed as ratios to creatinine, which tends to eliminate false negative results in dilute urine specimens. The normal urine value for cystine and homocystine combined is 66.8 +/- 52 (n = 50) mg per g creatinine. The normal value for homocystine alone is 29.9 +/- 16.8 (n = 24) mg per g creatinine. The simplicity of these procedures allows these quantitative methods to be used as screening tests for cystinuria and homocystinuria.

Amino Acids↗
PubMedDate not supplied

Lyme disease: an emerging infection with home healthcare implications.

The 11,424 cases of Lyme disease reported in 1994 represented a nearly 40% increase from the previous year. The dramatic increase of Lyme disease in the United States points to the need for home healthcare nurses to review their knowledge of the clinical manifestations, treatment, and prevention measures for this emerging infection.

Adolescent↗