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Biomedical subjects

W Anderson

Publications and source records attributed to W Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1996

Mouse bone marrow-derived mast cells roll on P-selectin under conditions of flow in vivo.

Increased numbers of mast cells are noted at sites of wound healing and inflammation. These mast cells are either recruited from the bone marrow or proliferate locally under cytokine stimulation. However, the molecular mechanisms mediating initial adhesive interactions between mast cell precursors and vascular endothelial cells are not well understood. We have used a syngeneic dorsal skinfold chamber model of microcirculation to study early events of mast cell-endothelial cell interactions by intravital fluorescence microscopy. Because "rolling" represents the earliest step of granulocyte adhesion under conditions of flow, our objective was to determine whether vascular selectins promote rolling of immature mouse bone marrow-derived mast cells (MBMMC) on endothelial cells lining murine blood vessels in vivo. In this study, titanium window chambers were implanted on the dorsal skinfolds of BALB/c mice. The passage of injected fluorescently labeled MBMMC within blood vessels of the striated skin muscle was observed by stroboscopic epi-illumination. As previously determined for other leukocytes, MBMMC were observed to roll in venules but not in arterioles or capillaries. Mice were also treated with neutralizing anti-E-selectin (mAb 9A9) and anti-P-selectin (mAb 5H1) antibodies and tested for their ability to block MBMMC rolling on venular endothelial cells. Intravenous administration of mAb 5H1 resulted in a marked decrease in MBMMC rolling, whereas mAb 9A9 and isotype matched control antibodies had no effect on the rolling flux of MBMMC. These studies represent the first identification of P-selectin as a rolling receptor for MBMMC, and demonstrate the use of a dorsal skinfold technique to study MBMMC-endothelial cell interactions under conditions of physiologic flow. Further studies will determine whether vascular selectins participate in the rolling and tissue recruitment of true circulating immature mast cell precursors in vivo.

Animals↗
PubMed1995

Use of bioluminescence to model the thermal inactivation of Salmonella typhimurium in the presence of a competitive microflora.

The survival of Salmonella typhimurium was investigated by bioluminescence and standard plating techniques in pure cultures and in the presence of competitors after the cultures were heated to 55 degrees C for increasing lengths of time. Decimal reduction (D) values increased from 0.43 to 2.09 min in the presence of 10(8) CFU of competitors ml-1, indicating a significant protective effect.

Bacteriological Techniques↗
PubMed1994

Modelling the thermal inactivation of Salmonella typhimurium using bioluminescence data.

Inactivation of micro-organisms by heat is a traditional food processing technique used to reduce or eliminate the microbial load in foods thus preventing bacterial associated disease and food spoilage. Models of thermal death kinetics are routinely used to predict the amount of heat required but such models are limited by the acquisition of accurate thermal death data for bacteria in situ and in complex microflora. In vivo bioluminescence from lux recombinant bacteria is an important alternative to traditional plate counts for examining bacterial injury and stress but the thermal instability of luciferase has appeared to preclude its application in heating studies. We have developed a procedure which overcomes the thermal instability of luciferase and demonstrate that computer generated models of the thermal injury of Salmonella typhimurium show equivalence between bioluminescence and viable count data.

Hot Temperature↗
PubMed1993

Differential effects of diclofenac and aspirin on serum glutamic oxaloacetic transaminase elevations in patients with rheumatoid arthritis and osteoarthritis.

OBJECTIVE: To examine elevations in levels of serum glutamic oxaloacetic transaminase (SGOT) in patients with rheumatoid arthritis (RA) and osteoarthritis (OA) taking placebo, aspirin, or diclofenac, and to seek possible explanations for the occurrence of these elevations. METHODS: We conducted a meta-analysis of individual case reports from 3 RA protocols and 5 OA protocols, encompassing 814 diclofenac-treated patients, 443 aspirin-treated patients, and 359 placebo-treated patients. All of the RA protocols had nearly identical inclusion and exclusion criteria, as well as safety studies and followup; the same was true for the OA protocols. Analysis included correlation analysis and multiple linear and logistic regression, accounting for numerous potential confounding variables, with the SGOT as the dependent variable. F tests were used for hypothesis testing. RESULTS: By several analytic approaches, the principal determinants of SGOT concentrations were found to be baseline SGOT value, the use of aspirin in RA patients, and the use of diclofenac in OA patients. Other significant factors contributing to an increase in SGOT concentrations were duration of therapy and, perhaps, daily dosage (mg/lb). Hypothesis testing supported these results. Given a statistically average patient, we predicted a 1-2% chance of a mildly elevated SGOT level occurring among placebo-treated patients, a 6-7% chance among diclofenac- or aspirin-treated patients with RA, a 12% chance among diclofenac-treated patients with OA, and a 2% chance among aspirin-treated patients with OA. CONCLUSION: This study demonstrates a powerful method for performing meta-analysis, using available individual patient data to examine numerous factors that may affect an outcome of interest. In this case, mild elevations of SGOT were examined and found to be related to baseline SGOT levels, diclofenac use (in OA), and aspirin use (in RA). Of numerous other potential factors examined, including age, sex, alcohol use, concomitant medications, and concomitant diagnoses, only duration of therapy and, to a small extent, daily dosage, were also consistent determinants of SGOT elevation. The SGOT elevations were minimal and were not related to the occurrence of clinical hepatitis: No clinical hepatitis occurred.

Arthritis, Rheumatoid↗
PubMed1993

The effect of dihydronicotinate N-substitution on the brain-targeting efficacy of a zidovudine chemical delivery system.

Enhanced brain delivery of zidovudine (AZT) has been demonstrated using a redox-based chemical delivery system (CDS). Optimization of the prototype AZT-CDS (5'-[(1-methyl-1,4-dihydropyridin-3-yl)carbonyl]-3'-azido-3'-deoxy thymidine ) was investigated by manipulation of the N-methyl group present on the dihydronicotinate portion of the molecule and examining the release of AZT in vivo in a rat model. Of the five compounds examined, all produced higher brain levels and lower blood levels of AZT than did AZT itself. In comparing the novel AZT-CDS analogues to the N-methyl benchmark, the N-propyl system proved to be the most efficient of the compounds tested.

Animals↗
PubMed1993

Patient use and assessment of conventional and alternative therapies for HIV infection and AIDS.

OBJECTIVE: To investigate the extent of recourse to alternative therapies among 184 HIV-positive patients who continued to attend conventional medical clinics. The study describes the specific alternative therapeutic modalities that were more commonly sought by our respondents, and provides data on the subjective assessment of the efficacy of both conventional and alternative therapies. METHODS: Demographic and behavioral information were obtained from standard, self-administered, anonymous questionnaires distributed at three HIV clinics in the Philadelphia area. RESULTS: Forty per cent of patients reported having used alternative or complementary therapies. Forty-two per cent of respondents who had been enrolled in clinical trials had used alternative therapies at some stage. Recourse to such therapies was significantly associated with risk-group affiliation, duration of seropositivity, and sex. The decision to use alternative therapies was not significantly related to age, race, education, religion or severity of symptoms. Of respondents using alternatives, 10% expected the unconventional treatments to cure their HIV infection, and 36% expected them to delay the onset of symptoms. CONCLUSION: The results of this study will contribute to conventional practitioners' understanding of those unconventional explanations and therapies for HIV infection that many patients find relevant and meaningful. Health-care workers should be aware of their patients' interest in participating in decisions about their treatment--whether alternative or conventional--and be prepared to work with them to achieve satisfactory outcomes.

Acquired Immunodeficiency Syndrome↗
PubMed1993

The impact of intraoperative autotransfusion on cardiac surgery. A prospective randomized double-blind study.

The effect of intraoperative autotransfusion during coronary artery bypass grafting was studied in a randomized double-blind trial involving 38 patients. Nineteen patients had the collected RBCs washed and autotransfused (autotransfusion group), while the remaining patients had their washed cells discarded (control group). Postoperative hemoglobin and hematocrit values were similar. Exposure to banked blood was markedly decreased in the autotransfusion group compared with the control group. In addition, the mean volume of banked packed RBCs transfused per patient was significantly less in the autotransfusion group compared with the control group. Platelet utilization also was markedly decreased in the autotransfusion group. Cryoprecipitate and fresh frozen plasma utilization also was less in the autotransfusion group than in the control group, but this did not reach statistical significance. We conclude that the intraoperative use of autotransfusion decreases the volume of homologous blood products transfused, which results in reduced exposure of the patients to banked blood products.

Adult↗
PubMed1992

Improved detection of antibodies to hepatitis C virus in dialysis patients using a second-generation enzyme immunoassay.

We tested serum samples from 99 patients undergoing maintenance hemodialysis for hepatitis C virus (HCV) antibodies using a first-generation, licensed anti-HCV enzyme immunoassay (EIA) and a second-generation anti-HCV EIA that detect three gene products c100-3, NS3, and core. Specimens that were repeatedly reactive by either or both screening assays were further evaluated by testing with supplemental EIAs and a dot blot immunoassay. There was 87.9% agreement between the licensed HCV EIA and the HCV EIA second generation. HCV EIA Second Generation detected 10 more positive specimens than HCV EIA, for an increase in detection from 33.3% (33/99) to 43.4% (43/99). We conclude that HCV EIA Second Generation improves detection of HCV infection in hemodialysis patients.

Adult↗
PubMed1992

Diagnostic value of pleural fluid cytology in occult Boerhaave's syndrome.

When Boerhaave's syndrome presents with atypical clinical features and eludes prompt diagnosis, delays in surgical therapy increase complications and mortality. We present a patient with occult Boerhaave's syndrome who had nondiagnostic esophageal contrast studies and thoracic computed tomography. Pleural fluid cytologic analysis established the presence of esophageal rupture by detecting undigested food particles.

Esophageal Diseases↗
PubMed1991

Redox derivatives of tranylcypromine: syntheses, properties, and monoamine oxidase inhibitor activity of some chemical delivery systems.

Several brain-targeting chemical delivery systems (CDS) based on a dihydropyridine----pyridinium salt type redox system were synthesized for the monoamine oxidase (MAO) inhibitor tranylcypromine (TCP). The dihydronicotinate moiety was chemically attached to the amino group of TCP by either an amide or substituted carbamate linkages. Physicochemical studies of the new derivatives, including chromatographic Rm determinations, were performed. Only the substituted carbamate-type derivatives manifested an increased lipophilicity relative to the parent compound. In vitro oxidation stability studies were also performed on selected derivatives using a ferricyanide-mediated method. Results of this assay showed that the dihydropyridine-type derivatives oxidized to the respective quaternary salt forms with stabilities which empirically correlated with other effective CDSs. Preliminary in vivo studies performed in rats indicated that some of the new derivatives exerted significant biological activity.

Animals↗