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Biomedical subjects

W Greene

Publications and source records attributed to W Greene.

At least 19 recordsLinked to original sources
PubMed2000

Use of integrins to date the endometrium.

OBJECTIVE: To compare traditional histologic dating criteria of the endometrium with immunohistochemical criteria based on epithelial integrin expression during the menstrual cycle. DESIGN: Prospective clinical study. SETTING: An academic teaching hospital. PATIENT(S): Fertile and infertile women undergoing endometrial biopsy. MAIN OUTCOME MEASURE(S): Immunohistochemical staining intensity and distribution (HSCORE) of three integrins and traditional histologic endometrial dating. RESULT(S): In 1,501 endometrial specimens, phase assignment-based integrin staining was 95% and 85% concordant with histology for the proliferative and early secretory phase, respectively, but only 54% and 49% concordant for the middle and late secretory phase, respectively. The greatest disagreement occurred during the midluteal phase. Of 1,090 patients who underwent sampling 6-10 days after detection of a urinary LH surge (corresponding to cycle days 20-24), multiple logistic regression analysis revealed that endometriosis was positively correlated and male factor infertility was negatively correlated with absent beta3 integrin subunit expression. Diagnosis and absent epithelial alpha4beta1 expression were not related. Patient age was not correlated with the incidence of abnormalities in integrin expression. CONCLUSION(S): Traditional histologic dating of the endometrium has remained the gold standard for nearly 50 years. Although the use of marker proteins provides additional information and may reflect endometrial function or receptivity, such markers cannot yet replace traditional methods of endometrial assessment.

Adolescent↗
PubMed1998

Relationships between dishabituation, sensitization, and inhibition of the gill- and siphon-withdrawal reflex in Aplysia californica: effects of response measure, test time, and training stimulus.

Previous studies have raised questions about the relationships between habituation, dishabituation, sensitization, and inhibition of reflex responses. To explore this issue further, a systematic study of these simple forms of learning was carried out in unrestrained Aplysia in which the amplitude as well as the duration of both the gill- and siphon-withdrawal reflexes were measured after either tailshock or mantle shock. The results suggest that transient reflex inhibition is not an invariant effect of noxious stimulation but depends instead on the response measure, test time, and type of noxious stimulus. Furthermore, the results suggest that dishabituation and sensitization may not involve different processes at the behavioral level; rather the observed differences between them may be due largely to an interaction between habituation and inhibition.

Animals↗
PubMed1998

Classical conditioning, differential conditioning, and second-order conditioning of the Aplysia gill-withdrawal reflex in a simplified mantle organ preparation.

Nonassociative learning was previously examined in a simplified preparation consisting of the isolated mantle organs and abdominal ganglion of Aplysia californica that is advantageous for relating cellular events to behavior (T. E. Cohen, S. W. Kaplan, E. R. Kandel, & R. D. Hawkins, 1997). Results of the current study show that the gill-withdrawal reflex in that preparation also underwent 2 associative forms of learning: classical conditioning and differential conditioning. In addition, the reflex underwent second-order conditioning with either forward or simultaneous pairing of a novel conditioned stimulus (CS2) and a previously conditioned stimulus (CS1). Moreover, extinction of CS1 after simultaneous second-order conditioning was accompanied by a decrease in responding to CS2, suggesting that the conditioning might have involved formation of an association between the CSs. In each of these paradigms, learning in the Aplysia mantle organ preparation resembled learning in vertebrates.

Analysis of Variance↗
PubMed1998

Multicenter evaluation of the Clostridium difficile TOX A/B TEST.

Clostridium difficile, the primary cause of nosocomial diarrhea in the United States and many other industrialized countries, is recognized as a major health concern because of its ability to cause severe intestinal disease leading to complications such as relapses and infections due to vancomycin-resistant enterococci. The disease results from two toxins, toxins A and B, produced by this pathogen. In this study, we evaluated the TOX A/B TEST, a new 1-h enzyme immunoassay (EIA) that detects toxins A and B. We compared the test with the tissue culture assay, which is recognized as the "gold standard" for C. difficile testing. Evaluations were performed in-house at TechLab, Inc. (Blacksburg, Va.) and off-site at four clinical laboratories. Of 1,152 specimens tested, 165 were positive by the TOX A/B TEST and tissue culture and 973 were negative by both tests. The sensitivity and specificity were 92.2 and 100%, respectively. The positive and negative predictive values were 100 and 98.6%, respectively, and the correlation of the TOX A/B TEST with tissue culture was 98.8%. When discrepant samples were resolved by culture, the sensitivity and specificity were 93.2 and 98.9%, respectively. The positive and negative predictive values were 100 and 98.8%, respectively, with a correlation of 99.0%. There were no specimens that were positive by the TOX A/B TEST and negative by tissue culture. Fourteen specimens were negative by the TOX A/B TEST but positive by tissue culture. Of these, two were negative by toxigenic culture, five were positive by toxigenic culture, and seven were not available for further testing. There were no indeterminate results, since the test does not have an indeterminant zone. In a separate study, 102 specimens that were positive by tissue culture and the TOX A/B TEST were examined in toxin A-specific EIAs. Two specimens that presumptively contained toxin A-negative, toxin B-positive (toxA-/toxB+) isolates were identified. One specimen was from a patient with a clinical history consistent with C. difficile infection. Isolates obtained from these specimens by selective culture on solid media and in broth tested toxA-/toxB+ when grown in brain heart infusion dialysis flasks, which stimulate in vitro production of both toxins. Our findings show that the TOX A/B TEST is suitable as a diagnostic aid for C. difficile disease because it correlates well with tissue culture and detects isolates that may be missed with toxin A-specific EIAs.

Bacterial Proteins↗
PubMed1997

L-deprenyl protects injured retinal precursor cells in vitro.

We evaluated the ability of L-deprenyl, a monoamine oxidase B-inhibitor (MAO-B), to preserve the viability of serum-deprived immortalized retinal precursor cells in vitro. We serum-deprived rat neural retinal ganglion cells immortalized by an incompetent retro virus. We instilled L-deprenyl in concentrations ranging from 0.01 to 100 microM. After 72 hours we performed a cell count of the L-deprenyl cultures and the control (no L-deprenyl instilled) with a hemocytometer and flow cytometry. We used transmission electron microscopy, DNA gel electrophoresis, and flow cytometry to determine the mechanism of cell death. This study showed that all five concentrations of L-deprenyl statistically increased the survival rate of immortalized retinal precursor cells at 72 hours in the serum-deprived medium (P = 0.01, ANOVA test). Ten microM and higher appeared to provide the greatest immortalized retinal precursor cell survival (12.7 x 10(-4) cells) compared to the control (5.8 x 10(-4) cells). Flow cytometry also demonstrated a higher percentage of surviving cells at 10 microM (80%) and 100 microM (76%) than with the control (58%) (P = 0.0017, chi2 test). Transmission electron microscopy, DNA electrophoresis, and flow cytometry showed that the mode of cell death was by apoptosis. This study suggests that L-deprenyl may be worthy of further investigation as a neuroprotective agent to treat chronic open-angle glaucoma.

Analysis of Variance↗
PubMed1993

The detection and quantification of feline immunodeficiency provirus in peripheral blood mononuclear cells using the polymerase chain reaction.

The polymerase chain reaction method (PCR) was used to detect feline immunodeficiency virus proviral DNA in peripheral blood mononuclear cells (PBMC) of a group of 8 experimentally infected cats. The proportion of PBMC containing provirus was determined from 6 to 32 weeks post inoculation (p.i.) by performing PCR on serially diluted samples of PBMC. Primers from the p15 and p24 regions of the gag gene were used and Southern hybridization using an end-labelled probe was required to confirm primer-specific products. Provirus was detected in 5 of 8 cats by 6 weeks p.i. in 50000 PBMC, and in all 8 infected cats by 8 weeks p.i. Provirus was not detected in PBMC from any of 3 FIV negative cats. The proportion of PBMC containing provirus in individual cats ranged from 1 in 70 to 1 in 99600 PBMC. There was no significant decline over time in the proportion of PBMC containing provirus. Sequencing of a segment (287 bases) of the gag region of a West Australian FIV isolate (T90) revealed only slight nucleotide divergence from the North American Petaluma and PPR isolates and wider divergence from the Japanese TM2 clone.

Animals↗
PubMed1993

Demonstration of silicon in sites of connective-tissue disease in patients with silicone-gel breast implants.

BACKGROUND AND DESIGN: Silica, Silastic, and silicone (any organic compound in which silicon replaces carbon) have been associated with a number of connective-tissue diseases, most commonly systemic sclerosis (scleroderma). Silicone is known to leak from breast implants and spread to surrounding tissues, including lymph nodes, but silicone's role in the origin and pathogenesis of the inflammation and fibrosis related to such conditions remains controversial. Synovial tissue, alveolar macrophages, and skin, each from three different patients with silicone-gel implants, plus the breast implant capsules from each of the three patients, were examined by light microscopy, transmission electron microscopy, and electron probe microanalysis for the presence of silicon-containing material. RESULTS: Silicon was identified within the fibrous breast capsule of each case, associated with a chronic inflammatory cell infiltrate. Silicon was also identified within tissues involved by chronic inflammation and fibrosis, namely, synovium, skin, and alveolar macrophages, in association with clinical, serologic, and histologic evidence of connective tissue disease. All three patients improved after removal of the silicone-gel breast implants. CONCLUSIONS: The presence of silicon-containing material within sites of connective-tissue disease supports a role for silicon in the origin or pathogenesis of such conditions in patients with silicone-gel breast implants. All patients with connective-tissue disease should be questioned about exposure to various forms of silicon. In those patients with known exposure, tissue specimens should be examined carefully for silicon-containing material and, if found, the source should be removed.

Adult↗
PubMed1992

A high proportion of early response genes are constitutively activated in T cells by HTLV-I.

Immortalization of T cells by HTLV-I is mediated by the X region of the virus and probably involves transactivation of cellular genes. We show that T cells transformed by HTLV-I constitutively express a high proportion of early response genes that are normally transiently induced following antigenic or mitogenic activation of T cells. Thus, HTLV-I-infected T cells display an 'early activation' phenotype that is distinct from the gene expression pattern of continuously dividing T cells. Ten early response genes representing a diverse array of functional categories were assayed. Four DNA-binding proteins/transcription factors including the p50 subunit of NF-kappa B were evaluated. A protein(s) encoded by the X region of HTLV-I appeared to contribute to up-regulated expression of most, if not all, of the early response genes. For those genes that could be assayed, increased transcriptional rates, but not substantial changes in mRNA half-life, were demonstrated in the presence of pX-encoded proteins, suggesting that the transcriptional transactivator, Tax, affects the induction or maintenance of transcription for these mitogen-inducible genes. Therefore, Tax may mimic or interact with a component(s) of the signal transduction pathway activated by antigen or mitogen treatment. These data demonstrate that early response genes, some of which probably play roles in initiating or maintaining cellular proliferation, are frequent targets of HTLV-I activation.

Blotting, Northern↗
PubMed1988

p55 IL-2 receptor mRNA precursors in murine T lymphocyte nuclei.

An unusual family of cDNA clones homologous to human p55 IL-2R sequences was isolated from the murine HT-2 Th cell line. These clones were mapped, partially sequenced, and compared with previously published human and mouse IL-2R sequences. They appear to consist of various combinations of exons and introns, suggesting that they are derived from p55 IL-2R mRNA precursors. The configuration of exons in the splicing intermediates indicates that the murine and human gene organizations are similar and that the 3' end of intron 3 is well conserved between the two species. RNA mapping experiments using nuclear, cytoplasmic, and total RNA and probes derived from various parts of the p55 IL-2R gene support and extend the sequence data. They indicate that detectable amounts of immature p55 IL-2R mRNA are found specifically in the cell nucleus of the HT-2 cell line. Similar data were obtained for the Th cell clone 52.3 and the cytotoxic T cell line CTLL. All these results indicate that the T cell nucleus contains significant amounts of immature p55 IL-2R mRNA.

Animals↗
PubMed1988

Corynebacterium xerosis septic arthritis.

A 62-year-old man developed acute septic arthritis due to Corynebacterium xerosis. The patient was treated with ampicillin and rapidly recovered. To the authors' knowledge this is the only reported case of septic arthritis due to C. xerosis. Clinical features of this case and the five previously reported cases of diphtheroid arthritis are discussed.

Acute Disease↗
PubMed1988

Experimental bovine respiratory tract disease with Haemophilus somnus.

Eight calves were inoculated into the bronchus with H. somnus. Thirteen calves were inoculated with bovine respiratory syncytial virus (BRSV) and 8 days later with H. somnus. All calves developed necrotizing, suppurative, lobular bronchopneumonia and pleuritis. Clinical signs of disease and pneumonic lesions were significantly more severe in calves that were sequentially inoculated with BRSV followed by H. somnus. Pneumonic lesions in the inoculated calves were similar to those described for naturally occurring H. somnus-associated respiratory tract disease. Control calves inoculated with BRSV alone or sham-inoculated with medium did not develop clinical signs of respiratory tract disease. The BRSV-inoculated control calves developed minimal pneumonic lesions.

Animals↗
PubMed1987

Structure and function of the human interleukin 2 receptor gene.

The gene encoding the human Interleukin 2 (IL-2) receptor consists of 8 exons spanning more than 25 kilobases on chromosome 10. Exons 2 and 4 were derived from a gene duplication event and unexpectedly also are homologous to the recognition domain of human complement factor B. Receptor gene transcription is initiated at two principal sites in normal activated T cells. Adult T cell leukemia cells infected with HTLV-I show activity at both of these sites, but also at a third transcription initiation site. Resting T cells do not contain detectable IL-2 receptor mRNA. Within 1 hour after stimulation with phytohemagglutinin (PHA), a large, presumably nuclear precursor RNA species is seen, which then gradually disappears. Mature IL-2 receptor mRNA forms appear within 8 hours after stimulation, reach peak levels between 8 and 24 hours, and then decline. Thus in PHA-activated lymphocytes the rise and fall in IL-2 receptor mRNA levels precede by more than 24 hours the peak and decline of IL-2 receptor protein expression occurring at the cell surface. Nuclease S1-protection assays indicate that IL-2 receptor mRNAs may differ in length due to the use of three different polyadenylylation signals. Further, these assays demonstrate the presence of transcripts that lack a 216-base segment within the protein-coding region and thus do not encode a functional IL-2 receptor. Nuclear transcription assays indicate that the increase in IL-2 receptor mRNA is reflected at the level of transcription. Thus, IL-2 receptor gene regulation controls IL-2 receptor expression at the cell surface and is intimately linked to the control of T-cell proliferation.

DNA↗
PubMed1984

Drug interactions involving cimetidine--mechanisms, documentation, implications.

In summary, cimetidine is a potent inhibitor of liver microsomal activity, which may also decrease hepatic blood flow. Other effects of the drug include inhibition of gastric secretion and intrinsic toxic properties. These effects, combined with the common use of cimetidine in clinical practice, make the risk of adverse drug interactions a relatively frequent risk in the clinical setting. Although a multitude of interactions with cimetidine has been evaluated, many of these are incompletely described or understood. At the present time, a potentially significant alteration of absorption appears to exist with only ketoconazole, elemental iron, vitamin B12 (long-term therapy), and pancreatic enzyme supplements (increased activity). Significant metabolic inhibition or decreased excretion appears to exist with warfarin, propranolol, theophylline, phenytoin, quinidine, possibly lidocaine and procainamide, and certain benzodiazepines. Other potential, but less well ascertained interactions may involve the narcotic analgesics, caffeine, ethanol, pentobarbital, imipramine, chlormethiazole, and metronidazole. In these settings, the clinician must be aware of interaction potential, and astutely monitor the patient during combination therapy. Other data indicate that concomitant administration of antacids may reduce the absorption of cimetidine, that the drug may protect against the toxic effects of acetaminophen overdose, and that combination with certain other myelosuppressants may carry a significant risk. Thus, in regard to these reports, cimetidine is a drug with complex effects on the absorption, elimination, and toxicity of other drugs. When used in the setting of multiple drug therapy, the clinician must be alert to potentially increased or decreased effects of the drugs mentioned in this review. In addition, one must be aware that other hepatically metabolised agents not mentioned here may be affected by the addition of cimetidine therapy. Because of the therapeutic successes demonstrated in the treatment of various disorders with cimetidine, one cannot disregard this agent. Thus, the responsibility for understanding and monitoring for the complex effects of this drug falls with the practicing physician.

Acetaminophen↗
PubMed1984

Failure of passive transfer in calves: comparison of field diagnosis methods.

Calves with serum immunoglobulin levels less than 800 mg/dl have a failure of passive transfer of maternal antibodies, those with 800-1600 mg/dl have a partial failure of passive transfer, and those with greater than 1600 mg/dl have adequate immunoglobulin levels. Tests for immunoglobulin level evaluation are most accurate when serum from healthy animals 1-8 days old is used. Of the sodium sulfite precipitation, zinc sulfate turbidity and glutaraldehyde coagulation tests, the first is the most useful field test for evaluation of serum immunoglobulin levels in calves. It is inexpensive, easy to perform and relatively accurate.

Animals↗