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Biomedical subjects

B Brown

Publications and source records attributed to B Brown.

At least 199 records · Page 11Linked to original sources
PubMed1991

Cellular origins of serum complement receptor type 2 in normal individuals and in hypogammaglobulinaemia.

A soluble form of complement receptor 2 (sCR2) is found in normal human serum. Amounts present are about 30-90 ng/ml, which is of the same order as reported for soluble CR1. Although B cells express surface CR2 and are the main peripheral blood source of sCR2 they do not appear to be the major tissue source of serum sCR2. Serum levels of sCR2 of patients with hypogammaglobulinaemia were not significantly different from those of normal individuals even in the case of two brothers with Bruton's X-linked agammaglobulinaemia (XLA) lacking (CD19+) B cells. On gel filtration through Sephacryl S-300 the sCR2 from XLA serum behaved exactly like sCR2 from normal serum or sCR2 affinity purified from cell supernates of a B lymphoblastoid line or from the T-ALL line MOLT-4. In all cases a single peak appeared at the same point in the chromatogram. Possible alternative sources of serum sCR2 are follicular dendritic cells (FDC) which are known to express CR2 strongly and T6+ lymphocytes within the thymus. Peripheral T cells from adults have not been reported to express CR2. However, investigation showed that cells from the Bruton's XLA cases produced small amounts of sCR2 in culture and although no CD21 was detected on the surface of the mononuclear cells by flow cytometry, the more sensitive direct antibody rosette test readily detected CD21. Further studies showed that non-B cells from control samples of cord blood or blood of young children also weakly expressed CD21.

Agammaglobulinemia↗
PubMed1991

Relationships among strength, endurance, weight and body fat during three phases of the menstrual cycle.

The purpose of this study was to investigate the relationships among body weight, body fat, and dynamic strength and muscular endurance during different phases of the menstrual cycle. Twenty-one female subjects, ages 18-36, with normal menstrual cycles and no dysfunction were tested for strength and endurance of the knee flexors and extensors on a Cybex II isokinetic dynamometer. Body weight and percent body fat were also assessed. Each subject was tested at three speeds (60 degrees, 180 degrees, and 240 degrees/sec) during three phases of the menstrual cycle: mensus (within 24 hours of onset); ovulation (13-14 days from onset); and luteal (10 days from ovulation). The data were analyzed descriptively and by Pearson Product-Moment Correlations with each phase of the cycle and between cycle phases. Results indicated high correlations among most strength measures at the three test speeds for each phase during the cycle and between the cycle phases. Overall, the different phases of the menstrual cycle had little or no effect upon the relationships among body weight, percent body fat, knee extension and flexion strength or endurance.

Adipose Tissue↗
PubMed1991

Elderly patients with congestive heart failure under prepaid care.

PURPOSE: Because of concern about the quality of care received by Medicare patients in health maintenance organizations (HMOs), the care of patients with congestive heart failure (CHF) in eight HMOs was compared with the care of fee-for-service (FFS) Medicare cases. PATIENTS AND METHODS: We compared the care of 170 patients with CHF enrolled in one of eight Medicare HMOs with the care of 191 similar FFS patients. Panels of expert physicians developed criteria for evaluating quality of care, and specially trained nurse clinicians abstracted medical records. RESULTS: Outpatient evaluation and management were similar in both settings, although HMO patients were significantly more likely to be advised to restrict salt intake. However, FFS patients with uncontrolled hypertension were more likely to have their medication regimens changed (62% versus 36%, p less than 0.01). Ejection fractions were obtained equally as often, and inpatient management was similar for both groups. Nonetheless, HMO providers scheduled follow-up visits within 1 week of hospital discharge more often (42% versus 27%, p less than 0.01). CONCLUSIONS: This study suggests that financial incentives of prepaid care are not detrimental to most aspects of care for CHF patients. More rapid follow-up after hospital discharge for patients with CHF suggests that HMOs may be more effective in delivering continuity of care for patients with chronic illness.

Aged↗
PubMed1990

Workstation variables and visual discomfort associated with VDTs.

We have investigated the effects of a range of workstation factors upon the visual symptoms experienced by a group of 92 visual display terminal (VDT) users. Subjects in the study kept a diary over five consecutive working days in which they recorded the types of visual and postural symptoms which occurred and the types of work tasks being performed. Each subject's workstation was analysed for screen legibility and stability, discomfort and disability glare, and required head postures. By the use of multiple regression analysis techniques we have considered the relative contribution of these factors to the symptoms reported by the users of these workstations. Screen legibility significantly influenced the occurrence of symptoms of ocular discomfort and vertical head movements significantly affected the incidence of postural/headache symptoms.

Journal Article↗
PubMed1990

The quality of ambulatory care in Medicare health maintenance organizations.

The quality of ambulatory care received by Medicare recipients who enrolled in health maintenance organizations (HMOs) was compared to the care received by fee-for-service (FFS) Medicare recipients, in a quasi-experimental, non-randomized design. Both samples were drawn from the four major geographic areas in the country, and included two types of HMO practices: staff/group models, and independent practice associations (IPAs). A panel of expert physicians developed criteria for evaluating ambulatory care, and medical record abstractions using these criteria were performed on 1,590 outpatient records: 777 FFS and 813 HMO (441 staff/group, 372 IPA). While individual items of medical histories and physical examinations were performed most often for staff/group HMO patients and least often in FFS patients, odds ratios (OR) for performance in staff/group HMO patients were particularly large for health maintenance items: tonometry (OR = 8.4), mammography (OR = 2.7), pelvic examination (OR = 5.3), rectal examination (OR = 2.9), fecal occult blood test (OR = 3.3). The results suggest that recommended elements of routine and preventive care are more likely to be performed for Medicare enrollees in staff/group HMOs than in FFS settings.

Aged↗
PubMed1989

Prognostic factors in mobile tongue and floor of mouth carcinoma.

This study identifies significant prognostic factors in squamous cell carcinomas of the anterior tongue and floor of mouth. It is clear that the TMN staging system does not account for other important variables that affect tumor prognosis. Tumor thickness and the presence of perineural invasion and intralymphatic tumor emboli should be examined in all resected tumors. Tumor thickness, tumor size, and perineural invasion all have an impact on survival and must be considered in treatment plans. Tumors measuring between 2 mm and 3 mm may or may not have metastases and further evaluation of this group needs to be done. Most importantly, the data in this study supports a multiinstitutional prospective evaluation of pathology specimens. Precise guidelines must be established for handling of the specimen, which must then be evaluated for the variables mentioned above. In this way, more definitive conclusions can be reached in the management of tumors of the anterior tongue and floor of mouth.

Aged↗
PubMed1989

Soluble forms of CD21 and CD23 antigens in the serum in B cell chronic lymphocytic leukaemia.

By using pairs of monoclonal antibodies (MAbs) to different epitopes on CD21 and CD23 antigens, it has been shown that both antigens are readily detectable in cell-free supernates of cultures of B cells expressing these antigens on the cell surface. The antigens remained in the soluble fraction after high speed centrifugation. Sera from normal individuals contained significant amounts of CD21 antigen, whereas little CD23 antigen was detectable. By contrast CD23 but not CD21 antigen was present in urine. Sera from patients with B cell chronic lymphocytic leukaemia (B-CLL) contained increased amounts of both antigens. The levels were related to the surface expression of antigen on the leukaemic cells and the number of cells in the blood. The possible functional role of soluble forms of B cell antigens and the diagnostic potential of their detection in body fluids are discussed.

Antibodies, Monoclonal↗
PubMed1989

Use of exchange wires in coronary angioplasty.

A 300 cm exchange guide wire was used as the primary wire in 59 consecutive patients referred for percutaneous transluminal coronary angioplasty. The success rate of the angioplasty using this as the only wire was 92% (54 of 59), and we were able to pass the exchange guide wire into the distal vessel in 56 of the 59 patients (95%). We believe the exchange wire technique has a place in the first-line approach to complex coronary angioplasty.

Angioplasty, Balloon↗
PubMed1989

Peripheral visual acuity with monovision and other contact lens corrections for presbyopia.

We have conducted two experiments to investigate the effect of monovision and other contact lens corrections for presbyopia upon peripheral visual acuity. In the first study, we measured binocular peripheral visual acuity using Landolt rings with seven subjects wearing a monovision correction. The Landolt rings were presented at eccentricities of 10, 20, 40, and 70 degrees on each side of the subject, with near additions of +1.50 D, +2.50 D, and no addition. We found no significant effect of monovision correction on peripheral visual acuity. In the second experiment we measured the peripheral visual acuity of 11 presbyopic subjects wearing distance contact lenses with lookover spectacles, soft progressive bifocal contact lenses, soft concentric bifocal contact lenses, monovision contact lenses, modified monovision contact lenses, and hard bifocal contact lenses using Koenig bar targets. There were no significant differences in peripheral visual acuity between any of the contact lens corrections for presbyopia.

Adolescent↗
PubMed1989

Temporal summation in age-related maculopathy.

We measured temporal summation in subjects with atrophic age-related maculopathy (ARM) and age-matched control subjects at photopic and scotopic luminance levels. Although the ARM subjects did show longer critical durations in each case these differences were not statistically significant. This result, in conjunction with our earlier work on temporal discrimination, indicates that the processes which are responsible for temporal summation of the eye (presumably located at the receptors) are more resistant to the degenerative processes of ARM than are those responsible for temporal discrimination. This may be because the simple threshold procedure used here does not sufficiently stress the temporal response system to show a deficit.

Aged↗
PubMed1989

High and low contrast acuity and clinical contrast sensitivity tested in a normal population.

Visual acuities obtained with a high contrast Bailey-Lovie chart (HCBL) and a low contrast Bailey-Lovie chart (LCBL) were compared with clinical contrast sensitivity function (CSF) measurements in a group of normal subjects with a wide range of refractive errors. We found high and significant correlations for the measurements obtained with the visual acuity tests, and between measurements obtained with the acuity tests and the CSF chart. These results indicate that the CSF test provides little additional information as a screening test in routine practice, and could probably be restricted in its use to patients in whom ocular disease is suspected.

Age Factors↗