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Biomedical subjects

M Brown

Publications and source records attributed to M Brown.

At least 487 records · Page 27Linked to original sources
PubMed1990

Time-resolved fluoroimmunoassay for enteric adenoviruses using the europium chelator 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid.

A time-resolved fluoroimmunoassay (TR FIA) was developed for the direct detection of adenovirus types 40 (Ad40) and 41 (Ad41) in stool specimens by using a monoclonal antibody (5D8/2C2) which recognizes both Ad40 and Ad41 but does not cross-react with other adenovirus serotypes. In this assay, the detector antibody is biotinylated directly rather than labeled with europium, and the fluorescent signal is generated on a solid phase in the presence of excess europium (Eu3+). The strength of the signal is dependent on the amount of a Eu3+ chelator [4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA)]-streptavidin complex bound by the biotinylated detector antibody (5D8/2C2). In a pilot study with 41 specimens, this TR FIA demonstrated a maximum sensitivity and specificity of 88% compared with SmaI restriction analysis of adenovirus isolates from the same specimens. TR FIA using the europium chelator BCPDA represents a feasible approach for the direct identification of specific adenovirus serotypes in stool specimens.

Adenoviridae↗
PubMed1990

Laboratory identification of adenoviruses associated with gastroenteritis in Canada from 1983 to 1986.

A retrospective analysis of adenovirus serotypes associated with gastroenteritis involved the examination of 143 stool specimens collected between 1983 and 1986 from symptomatic patients whose stools were positive for adenovirus by electron microscopy. The virus isolates obtained from 140 of the specimens were typed according to the SmaI cleavage pattern of the viral DNA and by neutralization with specific antisera. The predominant types were adenovirus type 31 (Ad31) (18%), Ad40 (16.9%), and Ad41 (38%), which together accounted for more than 70% of the isolates. The remaining virus isolates were typed as Ad1, 2, 3, 5, 7, and 12. DNA restriction analysis proved to be better than serum neutralization for identification of the enteric adenovirus serotypes in stool specimens. HindIII cleavage identified four Ad41 variants, none of which had a HindIII restriction pattern identical to that of the prototype strain Tak. Over the time period of the study, the incidence of Ad40 showed an overall decrease accompanied by an increased incidence of Ad41, while the incidence of Ad31 was relatively stable.

Adenoviridae Infections↗
PubMed1990

Histochemical and enzymatic characteristics of skeletal muscle in master athletes.

Many older athletes are capable of endurance performances equal to those of young runners who have higher maximal O2 uptakes (VO2max). To determine whether this is a result of differences in skeletal muscle characteristics, gastrocnemius muscle biopsy samples were obtained from eight master athletes [aged 63 +/- 6 (SD) yr] and eight young (aged 26 +/- 3 yr) runners. The young runners were matched with the master athletes for 10-km running performance and for their volume, pace, and type of training. Despite similar 10-km run times, VO2max was 11% lower (P less than 0.05) in the master athletes. Fiber type distribution did not differ between groups, with both groups having 60% type I and very few type IIb fibers. Succinate dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase activities, however, were 31 and 24% higher in the master athletes compared with the matched young runners, whereas lactate dehydrogenase activity was 46% lower (all P less than 0.05). The capillary-to-fiber ratio was also greater in the master athletes; however, capillary density was similar in the two groups, because of the master athletes' 34% larger (P less than 0.05) type I fibers. These differences in skeletal muscle characteristics may explain the master athletes' ability to perform as well as some young runners despite having a lower VO2max.

Adult↗
PubMed1990

Effect of beta-adrenergic blockade on myocardial function and energetics in congestive heart failure. Improvements in hemodynamic, contractile, and diastolic performance with bucindolol.

The hemodynamic effects of beta-adrenergic blockade with bucindolol, a nonselective beta-antagonist with mild vasodilatory properties, were studied in patients with congestive heart failure. Fifteen patients (New York Heart Association class I-IV) underwent cardiac catheterization before and after 3 months of oral therapy with bucindolol. The left ventricular ejection fraction increased from 0.23 +/- 0.12 to 0.29 +/- 0.14 (p = 0.007), and end-systolic elastance, a relatively load-independent determinant of contractility, increased from 0.60 +/- 0.40 to 1.11 +/- 0.45 mm Hg/ml (p = 0.0049). Both left ventricular stroke work index (34 +/- 13 to 47 +/- 19 g-m/m2, p = 0.0059) and minute work (5.5 +/- 2.2 to 7.0 +/- 2.6 kg-m/min, p = 0.0096) increased despite reductions in left ventricular end-diastolic pressure (19 +/- 8 to 15 +/- 5 mm Hg, p = 0.021). There was an upward shift in the peak + dP/dtmax-end-diastolic volume relation (p = 0.0005). These data demonstrate improvements in myocardial contractility after beta-adrenergic blockade with bucindolol. At a matched paced heart rate of 98 +/- 15 min-1, the time constant of left ventricular isovolumic relaxation was significantly reduced by bucindolol therapy (92 +/- 17 versus 73 +/- 11 msec, p = 0.0013), and the relation of the time constant to end-systolic pressure was shifted downward (p = 0.014) with therapy. The slope of the logarithm left ventricular end-diastolic pressure-end-diastolic volume relation was unchanged (p = 0.51) after bucindolol. These data suggest that chronic beta-adrenergic blockade with bucindolol improves diastolic relaxation but does not alter myocardial chamber stiffness. Myocardial oxygen extraction, consumption, and efficiency were unchanged despite improvement in contractile function and mechanical work. Thus, in patients with congestive heart failure, chronic beta-adrenergic blockade with bucindolol significantly improves myocardial contractility and minute work, yet it does not do so at the expense of myocardial oxygen consumption. Additionally, bucindolol improves myocardial relaxation but does not affect chamber stiffness.

Adrenergic beta-Antagonists↗
PubMed1990

Sickle cell disease. Summer camp. Experience of a 22-year community-supported program.

A summer camp for children with sickle cell disease (SCD) and other hemoglobinopathies has been in operation for 22 consecutive years (1,556 camper weeks). Two thirds of the campers had sickle cell anemia (SS). With the exception of 1 year, SCD-related medical problems occurred in 10 percent of the children. Episodes of illness were increased during the year when the camp was held at a site 2,200 feet above sea level. Children with SCD can enjoy a remote, physically challenging, and emotionally enriching program. Success requires an experienced and prepared medical staff who leave the organization and "on site" management of camp activities to expert recreational professionals.

Adolescent↗
PubMed1990

Magnetic resonance imaging correlates of internuclear ophthalmoplegia.

Internuclear ophthalmoplegia (INO) is a gaze disorder characteristic of lesions involving the medial longitudinal fasciculus (MLF). Two patients aged 62 and 74 years presented with acute neurologic deficits characteristic of INO. Computed axial tomography (CT) did not detect abnormalities in the region of the MLF. Magnetic resonance imaging (MRI) however, demonstrated brainstem hypersignals with long T2 characteristics in the region of the MLF which correlated with the clinical symptoms. These cases illustrate the value of the MRI in evaluation of patients with INO and suggest that MRI is superior to CT in evaluating gaze disorders attributable to brain dysfunction.

Aged↗
PubMed1990

Beta-adrenergic receptor sensitivity during sodium restriction and converting enzyme inhibition.

Adding converting-enzyme inhibitors to the salt depleted state is marked by a reduction in blood pressure despite compensatory increases in heart rate and plasma norepinephrine. This study investigated whether this increase in sympathetic function is also accompanied by an increase in beta-adrenergic receptor function. Ten subjects were studied following two separate five day hospitalizations on 10 mEq sodium diets while receiving either placebo or captopril. During low sodium with captopril, blood pressure and angiotensin II decreased, while heart rate, renin, norepinephrine and isoproterenol-stimulated cyclic AMP accumulation in lymphocytes increased. The results indicate that enhanced beta-adrenergic receptor function does accompany sympathetic activation during sodium restriction and converting enzyme inhibition and further support studies showing that the renin-angiotensin system plays the dominant role in blood pressure regulation in the sodium depleted state.

Adult↗
PubMed1990

Oxygen desaturation in women in labor.

Oxygen saturation and end-tidal CO2 tension were monitored in 15 healthy women during labor. Oxygen saturation was determined with a pulse oximeter and end-tidal CO2 with a CO2 monitor. Fetal heart rate, uterine contractions and maternal blood pressure were also monitored. End-tidal CO2 tension was followed to determine if falls in oxygen saturation during labor were related to hyperventilation. Ten of the 15 patients exhibited periods of oxygen saturation of less than 90%. End-tidal CO2 was consistently low, usually less than 30 mm Hg. Most, but not all (7 of 10), of the patients who showed desaturation had received narcotics. There were often periods of apnea and/or shallow respirations between contractions. These aberrations and hyperventilation-induced hypocarbia were probably the cause of the oxygen desaturation. No changes in fetal heart rate or low Apgar scores were noted.

Adolescent↗
PubMed1990

Medicaid versus state funding of community residences: impact on daily life of people with mental retardation.

The unintended effects on quality of life that flow from decisions regarding funding sources used to support community-based residential programs were documented. Results show that community residence program structures play an important role in determining quality of life after deinstitutionalization. Clients living under program structures flowing from the Medicaid ICF/MR funding source were less active and involved in life than were clients living in programs funded by non-Medicaid state sources. We hypothesized that the reason for this differential outcome was the result of Medicaid funding regulations and their interpretation, which create an institutional-like set of program structures leading to restrictive care patterns.

Activities of Daily Living↗
PubMed1990

Clinical features of adenovirus enteritis: a review of 127 cases.

We retrospectively analyzed the clinical features of 127 hospitalized pediatric patients whose fecal samples were positive for adenovirus (Ad) by electron microscopy during an 18-month period. Serotyping results obtained by microneutralization tests and restriction endonuclease analysis were available for 105 of 127 cases. There were 69 males and 58 females and 94% of patients were less than 4 years of age. The average body temperature was 38 degrees C rectal (range, 36.2-40.8 degrees C) with an average duration of fever of 1.6 days. The average duration of clinical illness was 8.8 days (range, 1 to 32 days). Although Ad 40 and Ad 41 were isolated in the majority of cases (59 of 105 (56%], Ad 31 was associated with 18 of 105 cases (17%). Of the 18 cases associated with Ad 31, 14 were nosocomial and associated with diarrhea. Our survey confirms the importance of fastidious enteric Ad in infantile diarrhea (Ad 40, Ad 41) and suggests that Ad 31 produces a clinical syndrome indistinguishable from that caused by Ad 40 and Ad 41. The occurrence of Ad enteritis in patients admitted for unrelated illnesses well after initial hospitalization suggests that Ad is also an important cause of nosocomial enteritis in our hospital.

Adenovirus Infections, Human↗