Search PubMed⌕ Search

Biomedical subjects

R Brown

Publications and source records attributed to R Brown.

At least 721 records · Page 40Linked to original sources
PubMed1982

Assessing potential predisposition of elementary school children to heart disease.

Physical well-being has been designated a top priority for the children in the Clovis (California) Unified School District. In an effort to diminish coronary risk factors and encourage a healthy life style, a health assessment battery was developed for students in grades 1 through 6. The battery included measurements in height, weight, blood pressure, sit and reach flexibility, and skin-fold test for body fat composition. More than 5000 students were administered the tests by a health assessment team consisting of two nurses, three physical education resource teachers, and two clerical staff members. A random sample of 100 males and 100 females at each grade level was utilized for the statistical analysis. The correlation between body fat and weight was .80 (p v .05) in the fifth and sixth grades. Body fat was positively correlated with both systolic and diastolic measures of blood pressure. The coefficient averaged .21 (p v .05) over the 6 grades for systolic and .22 (p .05) over the 6 grades for diastolic blood pressure. Future plans call for the development of a longitudinal profile of students, as well as establishing district norms for the test battery.

Adult↗
PubMed1982

Influence of the right ventricle on canine left ventricular function with PEEP.

In anesthetized dogs we evaluated the influence of increased right ventricular (RV) pressures on left ventricular (LV) function by comparing the hemodynamic effects of increases in RV afterload (pulmonary arterial pressure) produced by positive end-expiratory pressure (PEEP) with those due to pulmonary arterial occlusion (PAO). Left atrial (Pla) and right atrial (Pra) pressures increased with PEEP and PAO [for Pla: 3.1 +/- 0.7 Torr (PEEP), 2.4 +/- 0.9 Torr (PAO); for Pra: 2.9 +/- 0.4 Torr (PEEP), 3.1 +/- 1.2 Torr (PAO)]. RV septal-free wall dimension (RVD) increased, and LV septal-posterolateral dimension (L2) decreased with both conditions [increases in RVD: 1.9 +/- 0.3 mm (PEEP), 2.2 +/- 0.5 mm (PAO); decrease in L2: 1.1 +/- 0.4 mm (PEEP), 0.9 +/- 0.3 mm (PAO)]. Extracorporeal bypass of the great veins did not alter these findings. LV function curves showed less stroke work at any Pla during PEEP, this being unaffected by vagotomy. When the RV was bypassed, there were no PEEP or PAO related changes in Pla or LV function. Thus diminished LV function with PEEP is probably due to the influence on the LV of a stressed RV in this situation.

Animals↗
PubMed1982

Effect of interstitial fluid (kerosene) on pressure-volume characteristics of rat lung.

Although pulmonary interstitial edema has been estimated to decrease pulmonary compliance (CL), it has been experimentally difficult to demonstrate whether the observed changes in CL are directly due to the presence of interstitial fluid or if they result instead from concomitant pulmonary vascular engorgement and/or alveolar edema. Since kerosene-inflated lungs do not leak, we were able to use kerosene to measure the effect on CL of the accumulation of interstitial fluid (kerosene) in the postmortem rat lung. Pressure-volume (PV) studies of the lung were done during the progressive increase in interstitial fluid (kerosene). Analysis of the deflation limbs of the quasistatic PV curves obtained following serial inflations with kerosene indicated that the maximal volume of kerosene [MV35, equal to the maximum tissue plus airway volume at a transpulmonary pressure (Ptp) of 35 cmH2O] was 3.8 +/- 1.2 ml (31.0 +/- 11.8%) greater than TLC35 [air volume at Ptp of 35 cmH2O prior to kerosene inflation]. The increases in interstitial kerosene volume had no effect on kerosene PV characteristics, as was demonstrated by superimposing lung PV curves obtained at various states of interstitial filling. We conclude that the interstitial compartment is large and very compliant and that the presence of even great amounts of fluid limited to this compartment does not restrict lung expansion.

Animals↗
PubMed1982

Nonhomogeneous alveolar pressure swings: effect of different respiratory muscles.

We tested the hypothesis in dogs that during isovolumic inspiratory efforts the degree of nonhomogeneity of alveolar pressure changes is influenced by regional differences in respiratory muscle activity. Pressure distal to an occluded right lower lobe bronchus (PRLL) was compared with pressure in the occluded airway opening (PaO) during spontaneous inspiratory efforts (S), during right (RP), left (LP), and bilateral (BP) phrenic nerve stimulation, and during spontaneous inspiratory efforts after cutting both phrenic nerves (SCP), Upper and lower rib cage and abdominal dimensional changes were monitored by magnetometers. PRLL was greater than Pao during S and the difference was greater during BP and greater during RP, whereas with LP and SCP Pao exceeded PRLL. Compared with S, during RP, LP, and BP there was greater upper rib cage inward motion relative to abdominal outward motion. SCP resulted in opposite upper rib cage-abdomen relative motions. Thus activities of various muscle groups produced different regional pressures and deformations of rib cage and abdomen. These results may relate to potential errors in plethysmographic determination of thoracic gas volume in the presence of airway closure.

Abdominal Muscles↗
PubMed1982

A program for treating isolated elderly patients living in a housing project.

A comprehensive psychiatric treatment program called Outlook was designed to treat isolated residents of inner-city housing projects for the elderly. A large proportion of the elderly referred to the program had no family members or were estranged from them; approximately 80 per cent lived alone. All had multiple problems, and almost all were shown to be at high risk of institutionalization. During the first two years of the program, 108 clients were treated through a problem-oriented approach using a counselor-case manager and multiple therapies; only nine clients had to be referred to nursing homes or other institutions. The data suggest that well-designed programs can help elderly patients who have multiple problems but no family support to remain independent.

Aged↗
PubMed1982

Current approaches to the classification, characterisation and typing of pathogenic anaerobic bacteria.

Characterisation systems based on the demonstration of soluble antigens and toxins are of much practical value but have clear taxonomic limitations. This is illustrated by reference to our work with some of the pathogenic clostridia. The definition and classification of the anaerobic cocci is a difficult and continuing challenge. Systems for the classification and characterisation of the gram-negative non-sporing anaerobic bacilli are evolving well, though there are still some very difficult areas. A selection of the most helpful tests is indicated. Biotyping systems are compared with serotyping systems; the results of serological approaches to characterisation are encouraging. The further exploration of bacteriocin typing seems to be merited. The challenge of characterisation and classification of anaerobic spirochaetes commonly involved in human infections must now be taken up.

Amino Acids↗
PubMed1981

Circulating ceruloplasmin is an important source of copper for normal and malignant animal cells.

The relative uptake of copper from ceruloplasmin and non-ceruloplasmin plasma pools, by normal and malignant cells, was investigated in vivo and in vitro, using 64Cu and 67Cu. 1. Most of the copper administered intravenously to normal and tumor-bearing rats was removed within 1 h, a substantial portion entering the liver. There were differences in the apparent avidity of individual tissue for ceruloplasmin vs. ionic copper, but when calculated on the basis of actual microgram absorbed, all showed a preference for ceruloplasmin. 2. Appreciable amount of copper from either source were also absorbed by the tumors, and cultured Ehrlich ascites tumor cells showed a rapid uptake and marked preference for ceruloplasmin over non-ceruloplasmin copper, as did primary rat muscle cell cultures. 3. Ceruloplasmin protein was also absorbed by normal and neoplastic rat tissues, but less rapidly than ceruloplasmin copper, as determined by administration of pure [3H]leucine- or [125I]ceruloplasmin. Copper deficiency did not accelerate this process. 4. It is concluded that, at least in rat, ceruloplasmin is the preferred plasma source of copper for normal and malignant cells, and that the copper on ceruloplasmin turns over more rapidly than the protein moiety, a finding consistent with its role as a copper transport protein.

Animals↗
PubMed1981

The nonstress test: how long is enough?

Longer observation intervals might increase the positive predictive value of a nonreactive nonstress test (NST). One thousand one hundred and one NSTs were performed on 343 fetuses in 333 high-risk hospitalized patients. Recordings were terminated when five fetal heart rate (FHR) accelerations with movement occurred in any 20-minute period or after 120 minutes. The conclusion drawn was that the positive predictive value for morbidity and mortality of a nonreactive NST was 85.7% if conducted over 120 minutes, and that the negative predictive value for a reactive NST was 98.5%. A reactive NST was predictive of good fetal health regardless of the length of observation time necessary to demonstrate reactivity up to 120 minutes.

Apgar Score↗
PubMed1981

Progesterone administration and progressive sleep apneas.

Nine adult patients with obstructive sleep apnea syndrome were administered medroxyprogesterone acetate, 60 to 120 mg/day, and the effect of medroxyprogesterone on clinical symptoms and obstructive apneas during sleep was assessed. Four patients responded with resolution of daytime sleepiness, disappearance of pedal edema, and a decrease in the number of obstructive apneas during sleep. Cessation of therapy led to a return of daytime sleepiness in three and an increase in obstructive apneas in all four subjects. Two responders experienced side effects of alopecia or decreased libido. Before medroxyprogesterone therapy, responders were distinguished from nonresponders only by the presence of a significantly lower resting arterial oxygen tension during wakefulness. We characterize a subgroup of patients who benefit from medroxyprogesterone therapy by reducing obstructive apneas during sleep.

Adult↗
PubMed1981

Corneal topography. Corneascope.

We present an introduction to a clinical quantitative corneascope for measurement of corneal topography in detail. This instrument provides contour keratometry in all corneal meridians. We review the normal myopic and hyperopic eye contours, keratoconus, pellucid marginal degeneration, and wound gape and compression related to cataract surgery. We present a modified Placido disk for office use that incorporates the unique incident light image of the corneascope for rapid review of irregular corneal contours. Corneal topography irregularities frequently contribute to devastating refractive states of the eye and should be examined carefully when keratorefractive surgery is considered.

Cornea↗
PubMed1981

Differentiation of macrophages from Lewis lung carcinoma tumour cells in tissue sections by their alpha-naphthyl butyrate esterase activity.

The activities of alpha-naphthyl butyrate esterase, non-specific esterase, indoxyl esterase and acid phosphatase were studied histochemically in macrophages in cultures and in tissue sections of primary tumours and metastases of Lewis lung carcinoma (3LL). All macrophages in culture were stained by the alpha-naphthyl butyrate esterase procedure. In tissue sections, macrophages were intensely stained by the butyrate esterase procedure, while the tumour cells were not stained at all; macrophages were easily differentiated from 3LL cells. Non-specific esterase was evident in both tumour cells and macrophages. Indoxyl esterase and acid phosphatase were present in macrophages at the margin of the tumour only. The alpha-naphthyl butyrate esterase-positive macrophages differed in shape and location from acid phosphatase and indoxyl esterase-positive macrophages. This may indicate a difference in characteristics between macrophages found inside a tumour and those found at the tumour margins.

Acid Phosphatase↗
PubMed1981

Separation of tumor-seeking small lymphocytes and tumor cells using Percoll velocity gradients.

Using the polyoma virus-induced ascitic SEYF-a tumor, we evaluated isopycnic and velocity sedimentation gradients of Percoll as methods for separating tumor-seeking lymphocytes and tumor cells. It was established that the velocity sedimentation method is suitable for separation of small lymphocytes lodging within the SEYF-a tumor. This was confirmed by a serological analysis of the separated SEYF-a cell population. The results of this study strongly support our previously reported data demonstrating the in vivo coating of the tumor cells proper with potentially cytotoxic antibodies.

Animals↗
PubMed1981

Neuraminidase production by Bacteroidaceae.

The production of neuraminidase (EC 3.2.1.18) by 77 strains of Bacteroidaceae was investigated by techniques previously used to study neuraminidase production by clostridia. Conditions for culture and assay of Bacteroides fragilis neuraminidase were characterised. The enzyme is predominantly cell associated; it is not calcium dependent and the pH optimum for its production is c. 4.5. Most neuraminidase-positive Bacteroides strains produced the enzyme well in the test media but a few strains failed to produce it consistently in one or other of the media. Because of these occasional variations, strains were grown and tested in at least two media before being defined as neuraminidase negative. Within the B. fragilis group of species, B. fragilis, B. vulgatus, B. distasonis, B. ovatus, B. thetaiotaomicron and B. variabilis were neuraminidase positive while B. eggerthii, B. uniformis and B. splanchnicus were negative. Two subspecies of B. melaninogenicus (ss. melaninogenicus and ss. levii) were positive but the other (ss. intermedius) was negative. Strains of B. oralis and B. bivius produced the enzyme while B. ruminicola, B. disiens, B. asaccharolyticus and B. corrodens did not. The microaerophilic B. ochraceus were also positive. None of the Fusobacterium or Leptotrichia species tested produced neuraminidase. Our results for neuraminidase production are consistent for all strains of each species examined and we suggest that tests for neuraminidase production would be a valuable addition to biochemical tests currently used in taxonomic studies of the Bacteroidaceae.

Bacteroidaceae↗