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M Brown

Publications and source records attributed to M Brown.

At least 361 records · Page 20Linked to original sources
PubMed1994

Electrophoretic migration of adenovirus hexon under non-denaturing conditions.

While SDS-PAGE/immunoblotting is a valuable approach for the characterization of monoclonal antibodies, the denaturing conditions involved can compromise the recognition of conformational epitopes. This report demonstrates that a group specific epitope on adenovirus hexon can be recognized by immunoblotting following SDS-PAGE provided that samples are not boiled prior to electrophoresis. Under these conditions, multiple bands corresponding to native forms of hexon were detected above the position of the denatured hexon monomer. Among representative serotypes of subgroups A, B and F, two predominant bands, corresponding to hexon trimers and 'group of nine' hexons (GONs), were routinely observed. In contrast, higher order structures, in addition to trimers and GONs, were characteristic of subgroup C adenoviruses. These serotypic differences in stability of hexon structures may reflect differences in protein-protein interactions within the corresponding virions.

Adenoviruses, Human↗
PubMed1994

Clinical application of infrared thermography in the diagnosis of appendicitis.

To determine the clinical usefulness of infrared skin temperatures in diagnosing appendicitis, the authors conducted a prospective study of 86 adult and pediatric emergency department (ED) patients presenting during a 4-month study period with acute right lower abdominal pain. Skin temperature readings (FirstTemp digital thermometer, Intelligent Medical Systems, Inc, Carlsbad, CA) were taken from the right lower abdominal quadrant and a corresponding position on the left. An unpaired t test was used to determine if there was a significant difference between the right and left lower quadrants in patients with appendicitis. Discharged patients were followed up by telephone to determine any subsequent morbidity. A total of 23 patients had appendicitis confirmed by surgery; 63 subjects had other medical diagnoses. There was no significant skin temperature differential between the lower abdominal quadrants in either patient group (0.0 degree C vs 0.1 degree C; P > .5). Three patients had a skin temperature on the right that was at least 1 degrees C warmer than on the left; none of these patients had appendicitis. The results suggest that infrared thermography is not a sensitive diagnostic test for acute appendicitis in the ED population.

Abdomen↗
PubMed1994

The use of granulocyte-macrophage colony-stimulating factor to enhance hematologic parameters of patients with cirrhosis and hypersplenism.

In patients with end-stage liver disease complicated with hypersplenism, neutropenia and thrombocytopenia are risk factors for systemic sepsis and spontaneous bleeding. Granulocyte-macrophage colony-stimulating factor is a naturally occurring cytokine that promotes proliferation and differentiation of granulocyte and monocyte progeny cells. In addition, it is reported to promote the proliferation of megakaryocytes. Its use as an intravenous infusion is Federal Drug Authority (USA) approved for the enhancement of myeloid recovery following autologous bone-marrow transplantation. The present study was initiated to determine whether granulocyte-macrophage colony-stimulating factor could be used to increase the white blood cell and platelet count in patients with cirrhosis and hypersplenism and to determine whether the more convenient subcutaneous route can be used with the same efficacy as the recommended intravenous route. Nine patients with cirrhosis and hypersplenism manifested by a reduced absolute neutrophil count (mean value of 1300 +/- 200/mm3) were studied. In eight patients, Indium white blood cell splenic sequestration scans were obtained before and after the administration of granulocyte-macrophage colony-stimulating factor intravenous infusion or subcutaneously for 7 days. One patient had to discontinue the therapy due to a reaction to granulocyte-macrophage colony-stimulating factor. Following intravenous infusion of granulocyte-macrophage colony-stimulating factor, the mean absolute neutrophil count increased to 2600 +/- 1100/mm3. Following subcutaneous administration, the mean absolute neutrophil count increased to 4100 +/- 200/mm3. No significant change in platelet count occurred with either route of administration. Indium scans obtained before and after the treatment period revealed no significant difference in the splenic uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Efficacy of pseudoephedrine for the prevention of barotrauma during air travel.

STUDY OBJECTIVE: To determine the efficacy of decongestant prophylaxis in the prevention of symptoms of middle ear barotrauma (aerotitis media) during air travel. DESIGN: Prospective, parallel, double-blind, randomized trial. SETTING: Two commercial airports in Michigan. TYPE OF PARTICIPANTS: Two hundred fifty volunteers with a history of recurrent ear discomfort during air travel. INTERVENTIONS: Following randomization, each subject received 120 mg pseudoephedrine or placebo 30 minutes before flight departure. Recorded data included subject demographics, history of ear discomfort, and otologic examination. After arrival at their final destinations, volunteers were asked to complete a questionnaire and return it by mail to the investigators. Questions included the intensity and duration of otologic symptoms experienced while flying and possible drug side effects. MEASUREMENTS AND MAIN RESULTS: One hundred ninety subjects completed the study; 96 received 120 mg of pseudoephedrine and 94 received a placebo. The two treatment groups were similar with regard to age, sex, weight, and flight profile (P > .1). Ear discomfort was present in 32% (31 of 96) of those receiving pseudoephedrine versus 62% (58 of 94) of the control group (chi 2 = 15.34; P = .0001). Adverse effects were minimal; seven patients experienced drowsiness. CONCLUSION: Our results suggest that use of an oral decongestant before flying decreases the incidence of middle ear barotrauma associated with ambient pressure changes during air travel.

Adult↗
PubMed1994

Cigarette smoking and the age at onset of a first non-fatal myocardial infarction.

BACKGROUND: Smoking is a major risk factor for coronary heart disease. Discontinuance of smoking is associated with a reduction in the risk of coronary disease; this risk approaches the level among non-smokers after stopping smoking for periods ranging from 6 months to several years. We analyzed pertinent prospectively accumulated data from our multicenter postinfarction studies to gain further insight into the complex relationship between cigarette smoking and the premature occurrence of a first myocardial infarction. METHODS: Retrospective analysis of the relationship between the number of cigarettes smoked and the age at onset of patients experiencing their first non-fatal myocardial infarction was investigated in 2445 patients. The intensity of smoking was quantitated in terms of the average number of packs per day smoked during adult years, subcategorized in increments of a half-pack per day up to more than two packs per day. Ex-smokers were identified if they had stopped smoking 1 month before their index infarction. Analysis of variance was used to adjust for the effects of relevant confounding risk factors. RESULTS: The adjusted age for first non-fatal infarction progressively declined with increasing smoking exposure, with an average age reduction of 8.7 years (95% confidence interval; 7.2, 10.2) in those smoking more than two packs per day compared with non-smokers. The graded effect was somewhat more marked in women than in men. The number of cigarettes smoked before infarction had no effect on the severity of the acute infarction or on mortality from cardiac causes during more than 2-year post-hospital follow-up. Those who stopped smoking 1 month or longer before the infarction were significantly older at the time of first infarction than active smokers in all smoking categories. CONCLUSION: This study provides strong evidence that active smoking is associated with an earlier age at onset of first infarctions, with a striking inverse dose-response effect. Stopping smoking appears to reduce the premature occurrence of coronary events.

Age of Onset↗
PubMed1994

Growth during childhood and final height in type 1 diabetes.

The growth of 184 children with Type 1 diabetes was analysed using data collected prospectively in the Oxford district between 1969 and 1992. The overall mean height standard deviation score (Ht SDS +/- SD) at diagnosis was 0.35 +/- 1.05 which was significantly greater than the national standard of Tanner (1966). However, there is evidence of a secular trend in the heights of Oxford children over the last 20 years when compared with Tanner. When data from children with diabetes were compared with local controls, it was only the children aged 5-10 years at diagnosis who were taller (Ht SDS +/- SD, 0.58 +/- 1.14, versus 0.31 +/- 0.90, n = 73, p < 0.05). Those diagnosed under the age of 5 years (n = 37) were shorter (Ht SDS 0.12 +/- 0.93) and those diagnosed aged more than 10 years (n = 74) were similar in size (Ht SDS 0.22 +/- 0.98) to controls. These differences could not be explained by social class. Loss of height occurred between diagnosis and puberty, particularly in those diagnosed between the ages of 5 and 10 years. The pubertal growth spurt was blunted in all groups but this abnormality was more profound in the girls (mean peak height velocity SDS -1.09 +/- 1.02, p < 0.0005) than in the boys (mean peak height volocity SDS -0.5 +/- 1.14, p < 0.025). The mean final height SDS was -0.74 +/- 0.96 in those diagnosed < 5 years, 0.00 +/- 1.26 in those diagnosed between the ages of 5 and 10 years and 0.09 +/- 1.10 in those aged more than 10 years at diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Sources of stress for nurse practitioners.

The purpose of this study was to identify perceived stressors and manifestations of stress in nurse practitioners practicing in Missouri and California. The greatest sources of stress reported by the entire sample (N = 80) were in the categories of time demands and role restrictions. Missouri nurse practitioners found role restriction problems significantly more stressful than California nurse practitioners did. Manifestations of stress fell within the norms of non-psychiatric adults on the Symptom Check List 90-R.

Adult↗
PubMed1994

Pattern electroretinogram and automated perimetry in patients with glaucoma and ocular hypertension.

To determine whether the pattern electroretinogram can improve the objectivity of visual field assessment, 39 patients with glaucoma and ocular hypertension were studied. This was to establish whether there is a correlation between the pattern electroretinogram and the global indices (mean deviation and corrected pattern standard deviation) provided by automated perimetry using the Humphrey visual field analyser. A significant correlation was found between the amplitude of the P50 + N95 wave of the pattern electroretinogram and the mean deviation and corrected pattern standard deviation components of the visual field. The larger the deviation from normal of these indices, particularly the corrected pattern standard deviation, the smaller the amplitude of the pattern electroretinogram. This correlation between the pattern electroretinogram and visual field indices provides an additional measure of confidence when interpreting equivocal results of automated perimetry.

Adult↗
PubMed1994

Canine liver releases neuropeptide Y during sympathetic nerve stimulation.

To determine whether the liver or gut releases neuropeptide Y (NPY) from their sympathetic nerves, we performed bilateral thoracic sympathetic nerve stimulation (BTSNS) in halothane-anesthetized dogs and calculated gut and liver NPY spillover. BTSNS markedly increased hepatic NPY spillover (delta = +32 +/- 8 ng/min) and arterial NPY concentration (delta = +220 +/- 56 pg/ml), despite no effect on gut NPY spillover (delta = +8 +/- 7 ng/min). To determine the liver's contribution to this increase of circulating NPY, hepatic nerves were selectively stimulated (HNS). Liver NPY spillover increased markedly (delta = +114 +/- 42 ng/min, P < 0.025) during HNS, causing a large increase of arterial NPY (delta = +586 +/- 237 pg/ml, P < 0.025). Using this ratio of liver spillover to arterial increments of NPY, we calculated that the liver makes a major contribution (70%) to circulating NPY levels during BTSNS. The predominant form of canine NPY coeluted with synthetic [Met17]NPY and the minor form of canine NPY coeluted with the oxidized form of [Met17]NPY on high-performance liquid chromatography. We therefore conclude that dog NPY is likely [Met17]NPY and that the liver, rather than the gut, is a major source of circulating NPY during sympathetic nerve stimulation and perhaps stress.

Animals↗
PubMed1994

Interleukin-10 inhibits apoptotic cell death in infectious mononucleosis T cells.

T lymphocytes from patients with acute EBV-induced infectious mononucleosis rapidly die by apoptosis in vitro. Because human and viral IL-10 are likely to be induced during acute EBV infection and display a variety of functions on human T cells, we examined IL-10 effects on infectious mononucleosis T cell death. After 12 h of incubation in medium alone, only 35.6 (+/- 8.2%) of the originally seeded infectious mononucleosis T cells were viable. Addition of human IL-10 (100 U/ml) to T cell cultures significantly improved recovery of viable cells (71.3 +/- 6.2%, P = 0.0156). Viral IL-10 had comparable effects to human IL-10 in this system. Protection from death by human and viral IL-10 (100 U/ml) was dose dependent and continued over a 6-d culture period. The human IL-10 effect was neutralized by the anti-human IL-10 mAb 19F1. Morphology and analysis of DNA after separation on agarose gels showed that IL-10 inhibits loss of cell volume, chromatin condensation, and DNA fragmentation, characteristics of death by apoptosis. As assessed by [3H]thymidine incorporation, the T cells were not induced to proliferate by IL-10 above the level exhibited when first removed from blood. T cells protected from death by IL-10 proliferated to IL-2 and spontaneously killed sensitive targets as effectively as medium-precultured T cells. Thus, IL-10 promotes the survival of infectious mononucleosis T cells otherwise destined to die by apoptosis and may be critical for the establishment of immunologic memory after resolution of the illness.

Adolescent↗
PubMed1994

Repression of Fanconi anemia gene (FACC) expression inhibits growth of hematopoietic progenitor cells.

Bone marrow failure is a consistent feature of Fanconi anemia (FA) but it is not known whether the bone marrow failure is a direct and specific result of the inherited mutation or a consequence of accumulated stem cell losses resulting from nonspecific DNA damage. We tested the hypothesis that the protein encoded by the FA group C complementing gene (FACC) plays a regulatory role in hematopoiesis. We exposed normal human lymphocytes, bone marrow cells, endothelial cells, and fibroblasts to an antisense oligodeoxynucleotide (ODN) complementary to bases -4 to +14 of FACC mRNA. The mitomycin C assay demonstrated that the antisense ODN, but not missense or sense ODNs, repressed FACC gene expression in lymphocytes. Treatment with the antisense ODN substantially reduced, in a sequence-specific fashion, cytoplasmic levels of FACC mRNA in bone marrow cells and lymphocytes. Escalating doses of antisense ODN increasingly inhibited clonal growth of erythroid and granulocyte-macrophage progenitor cells but did not inhibit growth of fibroblasts or endothelial cells. The antisense ODN did not inhibit growth factor gene expression by low density bone marrow cells or marrow-derived fibroblasts. We conclude that, while the FACC gene product plays a role in defining cellular tolerance to cross-linking agents, it also functions to regulate growth, differentiation, and/or survival of normal hematopoietic progenitor cells.

Base Sequence↗
PubMed1994

Cost comparison: a desflurane- versus a propofol-based general anesthetic technique.

The purpose of this study was to compare the cost of a desflurane-based with a propofol-based general anesthetic technique. Fifty ambulatory orthopedic surgery patients were randomly assigned to one of two groups. Premedication and induction of anesthesia were standardized in both groups. In Group I patients, anesthesia was maintained with a propofol infusion and nitrous oxide-oxygen and in Group II patients, with desflurane-oxygen. The techniques used were identical to those routinely used with these drugs by our practitioners. The actual drug acquisition costs for the maintenance periods were calculated and compared, as was the duration of the postanesthesia care unit (PACU) stay (Phase I + Phase II). The drug acquisition cost for the maintenance period of general anesthesia with our desflurane-based technique was $11.24/h and for our propofol-based technique, $44.08/h. The length of PACU stay was not significantly different in the two groups. In conclusion, maintenance general anesthesia with our desflurane technique was considerably less expensive than with our propofol technique. PACU stay was not increased using desflurane as opposed to propofol in our study. Desflurane offers a cost effective alternative to propofol for ambulatory general anesthesia.

Adult↗
PubMed1994

MR imaging of high-grade cerebral gliomas: value of diffusion-weighted echoplanar pulse sequences.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of diffusion-weighted echoplanar MR imaging in the examination of high-grade brain gliomas compared with that of conventional spin-echo (SE) or fast spin-echo (FSE) MR imaging. We hypothesize that diffusion-weighted MR imaging may enable us to differentiate various tumor components on the basis of differences in the diffusion of water. SUBJECTS AND METHODS: Conventional SE and FSE MR images were obtained in 10 patients with high-grade brain glioma. Diffusion-weighted echoplanar MR images were obtained with a head gradient coil capable of providing diffusion-weighted imaging along the cephalocaudal axis. Using SE and FSE MR images as a baseline, we evaluated the diffusion-weighted MR images for usefulness in distinguishing tumor components on the basis of differences in diffusion. RESULTS: Areas of tumor that showed significant enhancement on T1-weighted SE MR images obtained after injection of contrast material were markedly hyperintense on diffusion-weighted images and had a lower apparent diffusion coefficient (ADC) than the ADCs for nonenhancing tumor and peritumoral edema. Cystic or necrotic portions of tumor showed the most signal suppression on diffusion-weighted images and were associated with the highest ADCs. On T2-weighted FSE MR images, areas of hyperintensity observed in white matter oriented parallel to the direction of the diffusion gradient could be differentiated into two patterns on the basis of findings on diffusion-weighted images: areas that showed marked signal suppression with a higher ADC, most likely representing areas of predominantly peritumoral edema, and areas that showed a lesser degree of signal suppression with similar but slightly lower ADCs than those of edema, most likely representing areas of predominantly nonenhancing tumor. CONCLUSION: Diffusion-weighted echoplanar MR imaging is a useful technique for examining high-grade cerebral gliomas. It enabled us to differentiate various components of the tumor (e.g., enhancing, nonenhancing, cystic, or necrotic) and to distinguish areas of predominantly nonenhancing tumor from areas of predominantly peritumoral edema when the abnormality was located in the white matter aligned in the direction of the diffusion-weighted gradient. Diffusion-weighted echoplanar MR imaging appears to be a powerful tool in the characterization of brain neoplasms.

Adolescent↗
PubMed1994

Physician opportunities in management: signs and portents.

There are many trends today that spell great opportunity for physicians who seek to shift their careers into management. Some of those trends are outlined here, with commentary on each opportunity presented. Like much in life, most opportunities contain uncertainties and unanticipated consequences. Thus, no opportunity comes without some possible negative side effects and blind alleys for the unaware. Some of these pitfalls are also presented, along with some suggested strategies for physicians who seek major roles in the management of the health enterprises of the future.

Career Mobility↗