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J Weed

Publications and source records attributed to J Weed.

11 recordsLinked to original sources
PubMed2001

A modified protocol for quantitative fit testing using the PortaCount.

A modified quantitative fit testing method has been developed for testing half masks using the TSI PortaCount respirator fit tester. This approach focuses on shortening the time for each exercise during fit testing; however, the shortened protocol is applied only to the very good-fitting masks. For marginal-fitting masks, the testing is carried out according to the full Occupational Safety and Health Administration (OSHA) respiratory protection standard (29CFR1910.134).(1) The shortened protocol (currently not approved by OSHA) still uses all the exercises required by the OSHA standard but for a shorter time (30 seconds [s] for each exercise instead of the usual 60 s). How good the fit has to be to qualify for a shortened exercise is determined by the statistical analysis of a large data set containing pass and fail fit-test data. The statistical analysis involves calculating the sensitivity and specificity of the pass and failed fit tests on half masks. From this analysis, a multiplication factor (K) to the OSHA pass/fail criterion was developed. For a respirator to undergo the shortened protocol, the fit factor obtained during any exercise must be K times the OSHA pass/fail criterion of 100 for half masks. Hence, this approach is more conservative than fit testing protocols that involve shortened exercises regardless of the fit. Nevertheless, this approach still saves time without compromising the accuracy of the fit test expressed in terms of sensitivity and specificity. For the existing data, 85 percent of the fit tests would have been performed according to the faster test protocol while only 15 percent of the tests would have been tested according to the full-length OSHA test protocol.

Decision Trees↗
PubMed2001

Aging and caloric restriction in nonhuman primates: behavioral and in vivo brain imaging studies.

In a long-term longitudinal study of aging in rhesus monkeys, a primary objective has been to determine the effects of aging and caloric restriction (CR) on behavioral and neural parameters. Through the use of automated devices, locomotor activity can be monitored in the home cages of the monkeys. Studies completed thus far indicate a clear age-related decline in activity consistent with such observations in many other species, including humans. However, no consistent effects of CR on activity have been observed. Selected groups of monkeys have also been involved in brain imaging studies, using magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI studies completed thus far reveal a clear age-related decline in the volumes of the basal ganglia, the putamen, and the caudate nucleus, with no change in total brain volume. PET analysis has revealed an age-related decline in the binding potential of dopamine D2 receptors in the same brain regions. These results are consistent with findings in humans. Although additional longitudinal analysis is needed to confirm the present results, it would appear that locomotor activity, volume of the basal ganglia, as well as dopamine D2 receptor binding potential provide reliable, noninvasive biomarkers of aging in rhesus monkeys.

Aging↗
PubMed1994

Leiomyosarcoma of the vulva: report of a case.

A 52-year-old female presented with a progressively enlarging vulvar mass. Pathological evaluation revealed a high-grade vulvar leiomyosarcoma. Immunohistochemical and ultrastructural studies were performed to support the diagnosis. In an effort to better understand the biology of this tumor additional immunohistochemical studies for the protein product of p53 tumor suppressor gene and estrogen receptor expression by tumor cells, as well as the type of immune cells infiltrating the tumor were performed. Tumor cells showed an overexpression of p53 protein and were estrogen receptor-positive. Macrophages and T and B lymphocytes infiltrated the tumor in moderate numbers with occasional lymphoid aggregate formation. This study is the first attempt to better understand the biology of these tumors.

B-Lymphocytes↗
PubMed1993

Tumor necrosis factor-alpha alters steroidogenesis and stimulates proliferation of human ovarian granulosal cells in vitro.

OBJECTIVE: To determine if tumor necrosis factor alpha (TNF-alpha) altered human granulosa-luteal cell proliferation and steroidogenesis. DESIGN: Aspirates of follicles from women undergoing in vitro fertilization were subjected to Percoll gradients to collect an enriched population of granulosa-luteal cells. The granulosa-luteal cells were subjected to culture for a period of 10 or 20 days in the presence or absence of various doses of human recombinant TNF-alpha (0.1 to 10.0 ng/mL). PATIENTS: Granulosa-luteal cells from nine patients were evaluated for their response to TNF-alpha in vitro. Patients with three follicles > 16 mm and a serum estradiol (E2) concentration of > 1,836 pmol/L were selected for study. RESULTS: Tumor necrosis factor-alpha increased granulosa-luteal cell number. By day 10 of culture, 10 ng TNF-alpha/mL doubled cell number and > 95% of the cells exhibited 3 beta-hydroxysteroid dehydrogenase. Tumor necrosis factor-alpha at 10 ng/mL increased progesterone (P) accumulation from day 4 through day 20 of culture. Tumor necrosis factor-alpha also increased E2 secretion but in a biphasic manner. During the first 14 days of culture, TNF-alpha increased E2, but thereafter E2 decreased to basal values by day 20. When steroidogenesis was expressed per 1,000 cells per days of culture, TNF-alpha did not increase P beyond controls but significantly increased E2 for the first 14 days of culture after which E2 per 1,000 cells declined. CONCLUSIONS: The results indicate that TNF-alpha stimulates granulosal-luteal cell growth and E2 secretion in vitro, and thus TNF-alpha may promote cellular events associated with formation of the corpus luteum; i.e., granulosa-cell proliferation and steroidogenesis.

Analysis of Variance↗
PubMed1992

Effects of septal lesions on a higher-order conditioned taste aversion: a preliminary analysis.

Septal-lesioned rats (n = 7) and nonsurgical controls (n = 7) were exposed to a higher-order conditioned taste aversion procedure and the effects of septal lesions on the development of a higher-order conditioned taste aversion examined. In Phase 1, septal and control rats were permitted to consume a sodium chloride solution and illness was produced by an injection of cyclophosphamide. Following a recovery period, in Phase 2, both groups were allowed access to a saccharin solution followed by 1 ml of sodium chloride placed directly inside the mouth of the rat. Subsequent preference tests for the septal-lesion group, the control group, and a second unconditioned control group (n = 5) showed the former two groups learned the higher-order conditioned taste aversion, as demonstrated by a marked aversion to the saccharin solution, and the septal lesions attenuated the severity of the conditioning process.

Animals↗
PubMed1990

Immunological evidence for a human ovarian tumor necrosis factor-alpha.

Tumor necrosis factor-alpha (TNF alpha) was localized to follicular and luteal compartments of the human ovary using a biotin strept-avidin immunocytochemical technique with polyclonal antibodies to human recombinant TNF alpha. Immunoreactive TNF alpha (I-TNF) was observed in granulosa cells of healthy antral and atretic follicles and appeared to be secreted by the granulosa cells, since it was present in the follicular fluid surrounding antral and degenerating granulosa. Preantral follicles did not exhibit I-TNF. I-TNF was in the cytoplasm of large granulosa-lutein cells and small paraluteal cells. Granulosa cells cultured on an Immobilon membrane exhibited I-TNF in the cytoplasm and I-TNF released onto the membrane, which appeared as a dark-red stain after immunolocalization. Granulosa cells cultured on plastic slides exhibited I-TNF throughout the cytoplasm. To determine if I-TNF was secreted by granulosa cells, granulosa cell-conditioned medium was examined for the presence of TNF by a double sandwich enzyme-linked immunosorbant assay using both monoclonal and polyclonal antibodies to human recombinant TNF alpha. Conditioned medium contained up to 800 pg TNF/500,000 cells after 24 h of culture. I-TNF was also found (100-170 pg/mL) in human follicular fluid. Immunoblot assay of I-TNF in cultured granulosa revealed approximately 240 pg TNF/250,000 cells. The results indicate that the human ovary contains I-TNF, and thus, a paracrine and/or autocrine role of TNF in human ovarian follicular function seems likely.

Adult↗
PubMed1985

Altered von Willebrand factor molecule in children with thrombosis following asparaginase-prednisone-vincristine therapy for leukemia.

Eleven consecutive leukemia patients with thrombosis induced by asparaginase-prednisone-vincristine therapy were studied to gain insight into the pathogenesis of this complication. Measurement of anti-thrombin III, plasminogen, factor V, and fibrin degradation products as well as platelet aggregation sensitivity to adenosine diphosphate disclosed no consistent abnormalities that would explain pathologic thrombus formation. A decrease in platelet counts observed in nine of 11 patients, prompted us to investigate the possible involvement of factor VIII in this disorder. Levels of factor VIII procoagulant activity, von Willebrand factor (vWF) and ristocetin cofactor were similar to findings for an identically treated comparison group who remained free of thrombotic complications. However, qualitative examination of vWF by crossed immunoelectrophoresis (CIE) revealed a distinct right shift of the immunoprecipitin lines in each of three thrombotic patients tested, whereas a normal profile was found in three similarly treated patients without the complication. This altered pattern had reverted to normal when CIE was repeated 2 to 7 months later. We postulate that the abnormal vWF is related to the development of thrombosis.

Adolescent↗
PubMed1984

Blood collection tubes for tricyclic antidepressant drugs: a reevaluation.

We tested clinical samples from patients receiving four commonly monitored antidepressant drugs--amitriptyline, nortriptyline, imipramine, and desipramine--to evaluate the reliability of currently available Becton-Dickinson Vacutainer brand vacuum blood collection tubes. Serum tubes (red stopper), heparinized plasma tubes (green stopper), and two types of serum separator tubes (SST) were evaluated. Antidepressant concentrations were measured by reversed-phase high-performance liquid chromatography. Antidepressant levels obtained using fresh serum (red stopper) or plasma (green stopper) yielded equivalent results. Serum collected in red-stopper tubes was stored at 4 degrees C for 4 weeks without detectable loss of antidepressant drugs. Significant concentration decreases for amitriptyline, imipramine, and desipramine were noted when serum was collected in SST tubes to such an extent that SST tubes cannot be used for the procedure. Bias attributed to SST tubes can interfere with the usefulness of clinical results over the entire therapeutic ranges of these drugs.

Amitriptyline↗
PubMedDate not supplied

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Artifacts↗