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Biomedical subjects

R Penny

Publications and source records attributed to R Penny.

At least 217 records · Page 12Linked to original sources
PubMed1978

Blood hyperviscosity in cryoglobulinaemia: temperature sensitivity and correlation with reduced skin blood flow.

Cryoglobulins cause an increase in plasma viscosity and this has been attributed to increased protein-protein interaction. The purpose of the present study was to analyse the interaction between red cells and these proteins by measuring the viscosity of whold blood from 21 patients with cryoglobulinaemia not only at high (73 sec-1) and low (0.18 sec-1) shear rates, but also at different temperatures. At 35 degrees blood hyperviscosity was found in 62% of the patients at the high shear rate, and in 76% of patients at the low shear rate. Cooling of the blood to 25 degrees caused an increase in the blood viscosity which was particularly marked at the low shear rate. The plasma viscosity was significantly increased at both temperatures. The hand blood flow was measured at 32 degrees, 27 degrees and 20 degrees in 12 patients to assess the degree of impairment of the peripheral circulation. The flows were significantly reduced at each temperature and there was an increase in the sensitivity of the flow through this region to local cooling. These findings indicate that in the presence of a cryoglobulin there is an increased viscous resistance, particularly at low flow rates. The temperature and shear rate characteristics of the blood viscosity suggest that cryoglobulins markedly potentiate red cell aggregation. This explains, at lest in part, the high incidence of skin and vascular complications in patients with cryoglobulinaemia and the characteristic localization of these features to exposed peripheral tissues.

Blood Viscosity↗
PubMed1978

Raynaud's disease: reduced hand blood flows with normal blood viscosity.

Hand blood flows and the blood and plasma viscosities were measured in patients with Raynaud's disease in an attempt to identify the mechanism of the episodic vascular insufficiency. Using venous occlusion plethysmography the following observations were made: (1) the hand blood flows were significantly less than in normals at 32 degrees, 27 degrees and 20 degrees C; (2) the percentage decrease in flow with cooling was greater in normals and (3) cooling of one hand from 32 degrees to 27 degrees C caused an abnormal decrease in flow through the contralateral hand. Using a rotational viscometer the blood and plasma viscosities were found to be normal at both high and low shear rates. The percentage increase in the blood viscosity with cooling from 35 degrees to 25 degrees was also normal. These studies demonstrate an increased constrictive response of the cutaneous vasculature of the hand to both local and reflex stimulation, and exclude a rheological abnormality, under conditions similar to those of the present study.

Adolescent↗
PubMed1978

Experience with large volume plasmapheresis in malignant paraproteinaemia and immune disorders.

Clinical experience with large volume plasmapheresis in a wide range of malignant and immune disorders is described. An average of 4 litres of plasma was exchanged for various colloid and electrolyte solutions. Patient tolerance was good but close medical and nursing supervision in monitoring fluid balance and adverse reactions to replacement fluids is necessary. Plasmapheresis has been established to be of benefit in immunoproliferative diseases when complicated by hyperviscosity, and may also have a place in other cases with haemostatic or renal impairment. Autoantibodies, alloantibodies and immune complexes can be removed by plasmapheresis, but the effect is usually transient and the procedure should be combined with immunosuppressive therapy in most cases. The removal of blocking factors in disseminated malignant melanoma is an experimental procedure at present, but initial results have been encouraging.

Adult↗
PubMed1978

Effects of anti-rheumatic drugs on immunological parameters.

A short review is presented of the immune and inflammatory sites of action of the more common agents in use by rheumatologists--in particular, corticosteroids, the non-steroidal anti-inflammatory and immunosuppressive drugs.

Adrenal Cortex Hormones↗
PubMed1978

Scleroderma: pathogenic factors and current management.

The aetiology of scleroderma remains unknown. Pathogenetic mechanisms may originate from vascular, collagen or immune abnormalities. These are reviewed and the current management although in the main unsatisfactory may alleviate a number of the distressing symptoms.

Blood Vessels↗
PubMed1978

Systemic factors contributory to retinal vein occlusion.

This study was undertaken in 79 patients with retinal vein occlusion to assess the different systemic mechanisms contributing to the occlusion, namely, intrinsic vessel disease and abnormalities of the blood constituents and blood viscosity. In 55 patients older than 50 years of age, important associations were hypertension, abnormal results on glucose tolerance test, hyperlipidemia, chronic lung disease, and elevated serum IgA levels. In the 24 patients younger than 50 years of age, male incidence was high and important associations were head injuries, hyperlipidemia, and the use of estrogen-containing preparations. Hyperviscosity and cryofibrinogenemia were prominent in both groups. The pathogenesis of retinal venous occlusion is complex involving interaction between the vessel wall and blood constituents.

Adult↗
PubMed1978

Gonadotropin excretion and body composition.

Urinary follicle stimulating hormone (FSH) and luteinizing hormone (LH) excretion was correlated with calculated total body water (TBW) and body fat (BF) in 140 normal girls and 142 normal boys, ages 3 to 16 years. In girls, there was a significant increase in gonadotropin excretion at the time of a significant increase in BF as a percent of body weight and decrease in TBW as a percent of body weight. Pubertal changes in body composition were seen in girls at the same chronological age and stage of puberty as increased gonadotropin excretion. Similar findings were observed in boys. Pubertal changes in body composition (an increase in TBW as a percent of body weight and decrease of BF as a percent of body weight) accompanied significantly increased gonadotropin excretion. Both developmental changes were seen at the same chronological age and stage of puberty. Our findings are consistent with the hypothesis that characteristic changes in body composition as well as the other hallmarks of puberty, including menarche in girls, result from increased gonadotropin and gonadal steroid secretion. They do not support the hypothesis that changes of body composition trigger increased hypothalamic function and hormone secretion leading to the subsequent events of puberty.

Adipose Tissue↗
PubMed1978

An immunologist's view of viral disease.

Immunologists see viral infection as a struggle between host defences and viral invasion. The outcome of such invasion may be sub-clinical or self limiting clinical infection or a less favourable outcome with chronicity, "slow virus" disease, autoimmunity or malignancy. A limited number of immune manipulations are possible in viral disease--immunization, immune enhancement with transfer factor or levamisole. An understanding of immune defences is vital at a time when antiviral chemotherapy is still so poorly developed.

Humans↗
PubMed1977

Depressed lymphocyte function after bereavement.

During 1975 twenty-six bereaved spouses took part in a detailed prospective investigation of the effects of severe stress on the immune system. T and B cell numbers and function, and hormone concentrations were studied approximately 2 weeks after bereavement and 6 weeks thereafter. The response to phytohaemagglutinin was significantly depressed in the bereaved group on the second occasion, as was the response to concanavalin A at 6 weeks. There was no difference in T and B cell numbers, protein concentrations, the presence of autoantibodies and delayed hypersensitivity, and in cortisol, prolactin, growth hormone, and thyroid hormone assays between the bereaved group and the controls. This is the first time severe psychological stress has been shown to produce a measurable abnormality in immune function which is not obviously caused by hormonal changes.

Adult↗
PubMed1977

Blood hyperviscosity with reduced skin blood flow in scleroderma.

The vascular complications of scleroderma have previously been attributed to the progressive obliteration of small vessels. Our study was carried out to determine whether abnormalities of blood viscosity occur in this disease, thereby contributing to the ischaemic process. Blood viscosity was measured in 20 patients using a rotational viscometer. At a high rate of shear, blood hyperviscosity was found in 35% of the patients and at a low rate of shear, in 70%. In addition there was a significant increase in the plasma viscosity which implicates changes in plasma proteins (fibrinogen, immunoglobulins) as causing the hyperviscosity. Measurement of the hand blood flow by venous occlusion plethysmography showed reduced flow at 32 degrees , 27 degrees , and 20 degrees C. A unique finding was a delayed recovery of the blood flow after cooling. These observations suggest that the increased resistance to blood flow in skin affected by scleroderma may be caused by an interaction between the occlusive vascular lesion and blood hyperviscosity. In addition, blood flow patterns and hyperviscosity could help distinguish scleroderma from primary Raynaud's disease.

Blood Viscosity↗
PubMed1977

Overnight gonadotropin excretion in normal females.

FSH and LH in acetone precipitates of timed overnight urine collections were measured by radioimmunoassay. FSH and LH urinary excretion extrapolated to 24 h was determined in 140 normal girls 3-16 years. Timed overnight urines were collected throughout a menstrual cycle from 3 normal adult women. FSH and LH progressively increased with age from 2.0 +/- 0.5 (FSH) and 2.0 +/- 0.4 (LH) IU/24 h for the 3--4 yr age group to 8.1 +/- 1.8 (FSH) and 11.5 +/- 3.8 (LH) IU/24 h for the 15--16 yr age group. Mean FSH and LH excretion for succeeding age groups (3--4, 5--6, 7--8, 9--10, 11--12, 13--14 and 15--16 years) increased significantly for the 5--6, 9--10 and 11--12 year age groups. Mean LH but not FSH excretion increased significantly for the 13--14 year age group. FSH and LH excretion increased progressively with stage of sexual development. In the 3 girls with established menstrual cycles. FSH (43.6 +/- 5.0 IU/24 h) and LH (113.7 +/- 7.8 IU/24 h) peaks occurred on the same day. Luteal phase excretion of FSH and LH was significantly lower than follicular phase excretion. Timed overnight urine collection allows integration of several hours of FSH and LH excretion.

Adolescent↗
PubMed1977

Episodic fluctuations of serum gonadotropins in pre- and post-pubertal girls and boys.

The concentrations of LH and FSH were determined in serum samples obtained at 15 min intervals during a 4 h period from seven normal girls, 9.5-16.5 years of age, and eight normal boys, 9.0-16.8 years of age. An episodic pattern of LH secretion was found in all subjects. There was no significant (P greater than 0.1) difference between girls and boys as to number of episodes (3.0 +/- 0.6 vs. 3.0 +/- 0.0 per 4 h), absolute LH increase (2.6 +/- 1.1 vs. 2.4 +/- 1.0 mIU per ml) or "apparent LH half-life" (64.3 +/- 20.8 vs. 76.1 +/- 23.4 min). Mean absolute increase during secretory episodes correlated (R = 0.89, P less than 0.005) with the mean LH concentration per 4 h, and a significant (P less than 0.025) inverse correlation (R = -0.52) was found between the mean per cent increment of the LH secretory episode and the mean "apparent LH half-life." Minor fluctuations of FSH were also observed. In girls and boys, the mean concentration of both gonadotropins increased with advancing puberty. The increase in LH concentration was due to an increase in the amplitude of secretory episodes rather than to an increase in the number of episodes. The increase in FSH concentration reflected a consistent elevation throughout the period of sampling.

Adolescent↗
PubMed1977

Evolution of the menstrual pattern of gonadotrophin and sex steroid concentrations in serum.

Consecutive daily serum samples were obtained over 25-30 days from 2 pre-pubertal girls (Stage I), 2 girls with breast development alone (Stage II); one girl with both breast development and pubic hair (Stage III), and 2 girls who were six months and three years post-menarche, respectively (Stage IV). All serum samples were assayed for LH, FSH, progesterone and 17-hydroxyprogesterone. Sera from 6 girls were assayed for testosterone, and sera from 3 were assayed for oestradiol. The patterns of gonadotrophins and sex steroid concentrations in both Stage I and Stage II girls were characterized by day to day stability. LH and FSH concentration was increased in Stage II subjects, while steroid concentration were similar to those in Stage I. The Stage III subject showed marked, apparently random, fluctuations in the concentrations of LH, FSH, oestradiol and 17-hydroxyrogesterone. In Stage IV, as early as six months post-menarche, there was a definte peak in the serum concentration of gonadotrophins, 17-hydroxyprogesterone and oestradiol. However, luteal phase length and maximal progesterone levels of these post-menarchial girls were less than those observed for normal adult females. These data are consistent with evolution of the adult menstrual pattern of hormone secretion through a series of developmental stages.

Adolescent↗
PubMed1977

The effect of acute and prolonged administration of prednisolone and ACTH on lymphocyte subpopulations.

The effect of acute and prolonged three week administration of prednisolone and ACTH on the numbers and function of T- and B-lymphocyte subpopulations in patients requiring corticosteroid therapy was studied. Prednisolone caused severe reduction in E-rosette-forming lymphocytes, phytohaemagglutinin response, EAC-rosette-forming lymphocytes and surface-membrane mu-positive B-lymphocytes maximal at 4--6 hr after administration with reversal sometimes to supernormal levels by 24 hr. Prolonged administration resulted in a similar pattern of response. Acute but not prolonged prednisolone administration caused a reduction in the percentage of E-rosette-forming lymphocytes maximal at 4 hr. ACTH caused moderate reduction in these parameters at 4 and 6 hr which remained low at 24 hr after prolonged administration.

Adrenocorticotropic Hormone↗
PubMed1977

Circulating immune complexes in retinal vasculitis.

Seventeen patients with retinal vasculitis, eleven with the peripheral type (Eales' disease) and six with the central type, were investigated to detect the presence of circulating immune complexes (IC) which might then be related to the pathogenesis of their disease. A systemic disease process was identified in six. IC in serum were inferred by the presence of complement (C) activation, rheumatoid factor, Clq or monoclonal rheumatoid factor precipitins, anticomplementary activity, elevated cryoglobulins, inhibition of erythrocyte-antibody (IgG-EA) rosette formation, increased numbers of peripheral blood lymphocytes bearing surface Ig, and spontaneous neutrophil chemotatic activity in plasma. Two or more parameters were positive in thirteen of seventeen patients, with chemotactic activity (69%) and inhibition of EA-rosette formation (59%) being the most frequently positive tests. No immunological differences were detected between the peripheral and central retinal-vasculitis groups. Several IC systems may operate in a give patient.

Adult↗