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Biomedical subjects

R Harris

Publications and source records attributed to R Harris.

At least 361 records · Page 20Linked to original sources
PubMed1985

Light and scanning electron microscopy of the same human metaphase chromosomes.

A technique has been developed to examine the same G-banded human metaphase chromosomes, first in the light microscope and then in the scanning electron microscope (SEM). A structural involvement in chromosome banding was confirmed by a positional correlation between the G-positive bands observed in the light microscope and the circumferential grooves between the quaternary coils of the metaphase chromosomes, observed in the SEM. In further support of this the regions between the grooves showed a positional relationship with the G-negative or reverse (R) bands. The examination of slightly extended metaphase chromosomes in the light microscope demonstrated that the G-banding pattern corresponded to that described by the Paris nomenclature for metaphase chromosomes. The arrangement of the circumferential grooves of the same chromosomes, observed in the SEM, was shown to relate to that described by the Paris nomenclature for prometaphase chromosomes. Therefore, using the SEM it is possible to demonstrate the details of prometaphase banding in metaphase chromosomes.

Chromosome Banding↗
PubMed1985

Clinical features, autoantibodies and HLA-DR antigens in rheumatoid arthritis.

HLA-DR4 was associated with seropositive but not seronegative disease in 105 Caucasians with rheumatoid arthritis (RA). There were no clinical or radiological differences between DR4 positive and negative RA groups, although 7 of 8 patients with early disease onset (less than 30 yr) were DR4 positive. High rheumatoid factor (RF) titers were more frequent in DR4 negative RA. A plot of the frequency distribution of RF titers in DR4 negative disease showed a bimodal distribution with seronegative and high titer groups. HLA-DR3 was not associated with high RF titers but was associated with high titers of antinuclear antibodies.

Agglutination Tests↗
PubMed1985

Genetic variants of properdin factor B (Bf) in rheumatoid arthritis.

Properdin factor B (Bf) phenotyping was carried out in 392 patients with rheumatoid arthritis (RA) and in 360 controls. In RA there were increased frequencies of both the Bf*S gene (83 vs 78%; pc = 0.0003) and the BfSS genotype 73 vs 61%; pc = 0.0002) and reduced frequencies of the Bf*F1 gene (0.5 vs 2.2%; pc = 0.03) and the BfFS genotype (20 vs 29%; pc = 0.0007). The frequencies of Bf*S in DR4 positive and DR4 negative RA were similar so that the findings were not accounted for by linkage disequilibrium between DR4 and Bf*S.

Arthritis, Rheumatoid↗
PubMed1985

Autoimmunity to native type II collagen--a distinct genetic subset of rheumatoid arthritis.

HLA phenotypes were determined in 60 Caucasoid patients with rheumatoid arthritis (RA) and normal serum antibody levels to native type II collagen. Antigen frequencies were compared with 52 patients with RA who had elevated antibody levels to native type II collagen. Both RA groups were compared with 163 healthy controls. A clinical comparison of both RA groups yielded few differences, except a decreased incidence of rheumatoid factor and a positive family history of RA and radiologically, increased osteosclerosis in the RA group with elevated antibodies to native type II collagen. HLA-DR4 was increased and HLA-DR7 was decreased in the RA group with normal antibody levels to native type II collagen. A comparison of both RA groups showed an increased incidence of HLA-DR4 in the normal antibody group, whereas HLA-DR7 was increased in the elevated antibody group. In the elevated antibody group the majority of patients possessed either HLA-DR3 or DR7 both of which are in strong linkage disequilibrium with HLA-DQw2. This immunogenetic data suggests that RA patients with autoimmunity to native II collagen form a distinct genetic subset of RA.

Adolescent↗
PubMed1985

Fluid replacement during hypothermia.

Hypothermia produces acidosis, depressed cardiac function, hypovolemia and hypotension. This study was designed to examine the cardiovascular dynamics involved with restoration of the hypovolemia before rewarming. Mixed breed splenectomized adult dogs (n = 16) were anesthetized with pentobarbital and cooled to a right atrial temperature of 25 degrees C at a rate of 3 degrees C X h-1. The animals were maintained at 25 degrees C for 6 h and rewarmed at 3 degrees C X h-1. Group 1 was given no fluid, Group 2 was given saline (20% of plasma volume infused in 10 min). 2 h after reaching 25 degrees C and Group 3 received saline just prior to rewarming. The hematocrit was elevated in all groups (p less than 0.05) upon cooling, but did not differ between groups even after saline was given. Cardiac output (Co) at 25 degrees C was 35% of precooled values. Group 2 increased their Q by 15% with fluid and this Q was maintained at higher levels than Groups 1 or 3 for the next 4 h. Plasma volume, heart rate, and cardiac contractility returned to control levels upon rewarming, but Q remained low (less than 10%). The level of Q at the start of rewarming did not affect the final level of Q.

Acid-Base Equilibrium↗
PubMed1984

Palmar keratoses and cancers of the bladder and lung.

In a case control study of the prevalence of palmar keratoses in 69 bladder cancer patients, 66 lung cancer patients, and 218 hospital controls palmar keratoses were more common in the cases, especially among those with cancer of the bladder. Above the age of 50 years, 87% of bladder cancer patients and 71% of lung cancer patients but only 36% of the controls had one or more keratoses. The prevalence increased with age and keratoses were more common in males. No features could be found which distinguished the keratoses in cases from those in controls.

Adult↗
PubMed1984

HLA antigens and risk factors for nephropathy in type 1 (insulin-dependent) diabetes mellitus.

This study of risk factors for diabetic nephropathy in juvenile Type 1 (insulin-dependent) diabetes mellitus compares two carefully characterised groups of patients, one with proteinuria (n = 23), the other a control group (n = 24) with no evidence of nephropathy despite more than 25 years of diabetic life. No significant difference was observed between the groups in any HLA-A, -B or -DR antigen of Bf allotype. DR3 was present in 87% of patients with proteinuria and 75% of the diabetic control group; DR4 was present in 48% of patients with proteinuria and 63% of diabetic controls; BfFl was present in 17% of patients with nephropathy and 9% of the diabetic control group. Compared with the control group, patients with proteinuria had significantly higher mean diabetic-clinic blood glucose concentrations before the diagnosis of microvascular disease, a significantly earlier age at diagnosis of diabetes, and had more often been treated with once-daily as opposed to twice-daily insulin regimens. Susceptibility to nephropathy in Type 1 diabetes appears to be determined by the quality of metabolic control and age of onset of diabetes; although the number of subjects studied was relatively small no evidence was found of any influence of HLA or Bf phenotype.

Adolescent↗
PubMed1984

Lack of correlation between lymphocyte activating determinants and HLA-DR on acute leukaemias.

The expression of allogenic lymphocyte-activating determinants (LAD) on 25 acute leukaemias has been compared with the expression of cell-surface antigens identified by HLA-DR allo- and xeno-antisera. The close correlation between LAD and DR known to occur on normal lymphocytes was not found in leukaemias. Twenty-two LAD+ leukaemias included 2 DR- cases, whilst 2 LAD- leukaemias were DR+. With the exception of 3 leukaemias all were strongly beta 2 microglobulin+. No correlation was found between the % DR+ cells and the level of lymphocyte stimulation. Separation of leukaemia cells on Ficoll gradients into fractions containing different proportions of DR+ cells did not correlate with LAD expression. Furthermore, antisera to DR antigens only partially blocked leukaemic LAD. The results support the notion that LAD on acute leukaemias are not necessarily associated with or identical to HLA-DR antigens, and that the lymphocyte activating capacity of HLA-DR may be modulated.

Acute Disease↗
PubMed1984

Optimum cell numbers for mixed lymphocyte responses in hanging-drop microcultures.

The conditions required for optimum mixed lymphocyte culture (MLC) responses in hanging-drop (HD) microcultures in Terasaki trays have been investigated. Compared with conventional (200 microliter) MLC, HD-MLC required 5-10 times fewer cells, and 10% of the amount of culture medium and 3H-thymidine label. Peak uptake of label in HD-MLC was mutually responder-stimulator concentration dependent. Differences in response to related and unrelated lymphocytes indicate that HLA-D determinants are detected in HD-MLC.

Cell Count↗
PubMed1984

Relationship between health beliefs and psychological variables in diabetic patients.

The present paper is focused on the relationship between psychological variables and health beliefs in 93 diabetic men. A Diabetes Health Belief Scale was used to assess general health motivation, treatment beneficial, severity, susceptibility, psychological barriers, cues to action, and structural elements. The psychological variables included two measures of locus of control, depression, somatization, interpersonal sensitivity, obsessive-compulsiveness, anxiety, self-esteem, and attitudes toward diabetes, doctor, and medical care. Ten of the 11 psychological variables were correlated with various aspects of health beliefs. This indicates the extent to which the health beliefs are enmeshed with the psychological dynamics of the person. It would seem important to take such a psychological profile into consideration when attempting to understand and even alter the health beliefs.

Attitude to Health↗
PubMed1984

Adrenergic blockade does not change ventilatory response to CO2 in awake resting goats.

Although adrenergic agonists increase resting ventilation and responsiveness to CO2, there are conflicting data about the effect of adrenergic blockade on ventilatory responses. In this study, we investigated the effect of alpha- or beta-adrenergic blockade on the response to hyperoxic CO2 rebreathing in awake goats. In 5 goats, studied before and after intravenous administration of phentolamine or propranolol, there was no difference (compared to control studies) in the mean slope, x-intercept, or ventilation at end-tidal PCO2 (PETCO2) = 70 torr for the CO2 response curves after either drug. When mean inspiratory flow rate (VT/Ti) was plotted against PETCO2, there was also no change in these measurements after propranolol. After phentolamine, there was a slight decrease in the slope and x-intercept, but no change in VT/Ti at PETCO2 = 70 torr. We conclude that acute administration of alpha- or beta-adrenergic blockers does not affect ventilatory response to CO2 inhalation in goats, and suggest that adrenergic activity is not an important modulating influence for CO2 responsiveness in this species.

Animals↗