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Biomedical subjects

C Loveday

Publications and source records attributed to C Loveday.

90 records · Page 5Linked to original sources
PubMed1985

Changes in intravascular complement, kininogen, and histamine during Jarisch-Herxheimer reaction in secondary syphilis.

Nine patients with secondary syphilis and one control subject were observed for eight hours after the administration of penicillin. Serial clinical observations were made, and blood samples were obtained for the analysis of complement, histamine, and kininogen. Six patients showed Jarisch-Herxheimer reactions, the intensities of which were found to parallel certain changes in activity of complement and concentrations of histamine and kininogen. Results were analysed statistically. Significant falls were seen in: total haemolytic complement (CH50), C1 inhibitor, C3, functional (haemolytic) C4, and to a lesser extent total C4. Split products of C3 were shown in five of the six patients who had a reaction. There was no change in total glycine rich beta-glycoprotein (GBG) or glycine rich gamma-glycoprotein (GGG) or evidence of conversion of GBG to GGG. Plasma kininogen concentrations fell and plasma histamine concentrations rose appreciably before and during the clinical phase of the reaction. These results are discussed in relation to the clinical features and possible pathogenic mechanisms of the Jarisch-Herxheimer reaction.

Adult↗
PubMed1984

Desensitization of test anxious urban community-college students and resulting changes in grade point average: a replication.

Ninety-seven self-referred students applied for enrollment in a behavior modification program to reduce test anxiety. Those whose free time coincided with the workshop times served as the experimental group (N = 42), while the remainder served as the control group (N = 55). At the end of the treatment semester, results indicated that students who participated in the program had improved their academic averages more than the control group, as measured by Mann-Whitney U test. After the workshop series, the experimental group reported less debilitating anxiety than the control group, as measured by the Alpert-Haber Test Anxiety Questionnaire. There was no comparable finding for facilitating anxiety. These results support those reported by Hudesman and Wiesner (1979) on a similar sample.

Achievement↗
PubMed1979

Leucocyte ascorbate levels and postoperative deep venous thrombosis.

Forty-four general surgical patients were included in a prospective, randomized double-blind controlled trial of ascorbic acid (500 mg b.d.) or placebo for 7 days before operation. This was to test the hypothesis that vitamin C may reduce the instance of deep venous thrombosis postoperatively. Venous blood samples were taken before entering the trial, just immediately before surgery, on the day of operation and on three further occasions at 3-day intervals postoperatively for leucocyte ascorbic acid concentration (LAC). Venous thrombosis was diagnosed using the 125I-fibrinogen test and the leg scans interpreted by Roberts' criteria. There was no significant difference in the incidence of DVT between the treatment and placebo groups. In those with DVT (n = 23) the mean LAC on the day of operation was not significantly different from that in those without DVT. However, on the sixth and ninth postoperative days LAC levels were significantly lower in the DVT group. These results suggest that the administration of ascorbic acid preoperatively does not reduce the incidence of DVT, but a striking decrease in the LAC levels in the DVT patients is in keeping with the hypothesis that the initial event in the pathogenesis of DVT is adherence of leucocytes to the venous endothelium.

Ascorbic Acid↗
PubMed1976

Changes in intra-vascular complement and anti-treponemal antibody titres preceding the Jarisch-Herxheimer reaction in secondary syphilis.

Six patients with secondary syphilis and one control subject were observed over a period of up to 8 hr following the administration of either penicillin or erythromycin. Serial clinical observations were made and blood samples obtained for complement and serological analysis. The patients showed Jarisch-Herxheimer reactions (JHR) of varying intensity which were found to be preceded by and to parallel in degree certain changes in complement and syphilitic antibody titres. Falls in total haemolytic complement, in C4, C3, C6 and C7 and a marked drop in C1INH were observed. There was no change in total GBG/GGG or evidence of conversion of GBG to GGG. Associated falls occurred in the titres of the QFTA and the QTPHA antibodies but not of the QVDRL or QTPI antibodies. C3 conversion was found in the two patients that suffered severe reactions. Immune complexes were not detected and it is suggested that complement activation occurred in the extra-vascular body compartment. The significance of these changes in relation to other plasma enzyme systems and to the development of the full clinical picture of the JHR is discussed.

Antibodies, Bacterial↗
PubMed1973

Effects of salicylates on blood changes in mycoplasma arthritis in rats.

1. The polyarthritis produced in rats by i.v. inoculation with Mycoplasma arthritidis was made more severe by salicylates.2. The infection increased the erythrocyte sedimentation rate (ESR), serum lysozyme, counts of total white blood corpuscles, polymorphonuclear cells and lymphocytes, haemolytic serum complement (CH 50) and its component C3. Salicylates enhanced the rise in ESR, CH 50 and C3, but suppressed the rise in lymphocytes and even induced a fall.3. Salicylates did not interfere with the development and action of metabolic inhibition antibodies against M. arthritidis, and did not promote the growth of M. arthritidis.4. Rats treated with salicylate during the first infection acquired the same immunity to reinfection as did infected controls.5. Salicylates did not render rats susceptible to M. fermentans which is non-pathogenic to rats, but may be involved in human rheumatoid arthritis.

Animals↗
PubMed1973

Effects of suramin on complement, blood clotting, fibrinolysis and kinin formation.

1. The inhibition by suramin of complement components, and of blood clotting, fibrinolytic, and plasma kinin forming factors depended on the conditions of the assay and on the substrates used.2. Haemolysis by complement was more effectively inhibited in red blood cell suspensions, than in agarose gel plates. In esterolytic tests, the activation of component 1 (C1) to C1 esterase was significantly inhibited by 0.1-0.3 mM suramin, and the activity of C1 esterase by 0.5 mM suramin.3. Part of the anticoagulant effect of suramin is due to inhibition of the action of thrombin on fibrinogen.4. Suramin did not inhibit fibrin degradation by the fibrinolytic system in plasma. In esterolytic tests, the activation of plasminogen was more potently inhibited than the activity of plasmin.5. Activation of plasma kallikrein, measured either by kinin formation or by esterolysis, was inhibited by 0.1-0.3 mM suramin. Active plasma kallikrein was inhibited by 0.3-0.5 mM suramin. Pancreatic kallikrein was weakly inhibited, and urinary kallikrein not at all.

Animals↗
PubMed1973

Blood changes in experimental arthritis in two types of genetically different rats.

1. Rats genetically resistant to dextran and other agents producing the anaphylactoid reaction (NR rats), have a higher polymorph count than do rats which react to these agents (R rats).2. NR rats do not develop polyarthritis when a hind paw is injected intradermally with Freund's adjuvant.3. The polyarthritis produced by an intravenous injection of Mycoplasma arthritidis culture develops more slowly in NR rats than in R rats.4. It is not clear whether the higher polymorph count in NR rats is a main factor in determining their resistance to adjuvant-induced arthritis.

Animals↗
PubMed1972

Activation of arginine and tyrosine esterase in serum from patients with hereditary angio-oedema.

1. The role of clotting factor XII in the activation of the complement subunit C1s to C1 esterase was examined.2. In sera from patients with hereditary angio-oedema who lack the alpha(2)-glycoglobulin C1 inhibitor, silicates and other potent activators of clotting factor XII induced far less C1 esterase activity than did the weaker factor XII activators, carrageenin and cellulose sulphate. In contrast, the intensity of the induced plasma kallikrein activity corresponded more closely to the clot-promoting effect of the factor XII activators.3. Spontaneous generation of C1 esterase activity was only slightly delayed in hereditary angio-oedema sera previously depleted of factor XII. In normal sera, C1 esterase did not develop spontaneously and could not be induced.4. Experiments with inhibitors suggested that the spontaneous activation of C1s may consist of two phases: factor XII and other plasma proteases first activate small amounts of C1s; the resulting C1 esterase then activates the bulk of C1s. The observed spontaneous activation suggests that when fully activated, the C1s present in 1 ml of human serum will hydrolyse 1-2 mumol of ATEe/minute.

Angioedema↗
PubMed1971

In vivo effects of cellulose sulphate on plasma kininogen, complement and inflammation.

1. The in vivo action of cellulose sulphate was studied in an attempt to clarify the role of complement and kinin formation in inflammation.2. Inflammatory oedema was produced in the rat paw by heat (45.5 degrees C), and on the ear by xylene. The oedema was assessed by comparing the ratio of fresh wet weight to dry weight of corresponding injured and non-injured parts.3. Following cellulose sulphate (6.5 mg/kg i.v.), plasma kininogen concentrations were promptly reduced by 90% or more. The reduction in complement titres was statistically significant and ranged from 17 to 65%. No toxic effects were observed. The oedema caused by heat or xylene was not reduced in these rats.4. Cellulose sulphate (80 mg/kg i.p.) given over 3 days depleted plasma kininogen by about 90%, but reduced complement titres only slightly. These rats gained less weight and their condition was poor. Blood clotting was impaired and widespread haemorrhages were found. Heat and xylene produced significantly less oedema than in control rats. This diminished response is attributed to toxic side effects of cellulose sulphate, rather than depleted plasma kininogen and reduced plasma complement.5. The results suggest that the inflammatory reactions to thermal and chemical injury can fully develop when plasma kininogen and complement are lowered.

Animals↗
PubMed1970

Effect of cellulose sulphate on serum complement.

Cellulose sulphate 50-600 mug/ml reduces complement titres in human serum. This effect is, in contrast to the clot-promoting and plasma kinin forming action of cellulose sulphate, not mediated by clotting factor XII.

Blood Coagulation↗
PubMedDate not supplied

Storage and preservation of whole blood samples for use in detection of human immunodeficiency virus type-1 by the polymerase chain reaction.

Methods used in the diagnosis of human immunodeficiency virus type-1 (HIV-1) infection by the polymerase chain reaction (PCR) usually require the separation of lymphocytes from a whole-blood sample within 24 hours of patient sampling. A method is described in which blood samples are mixed with a cryopreservative ('Glycigel'), stored frozen, and DNA suitable for use in an HIV PCR recovered. Samples can be stored at -20 degrees C for up to 3 months and still give positive results with all samples from infected patients; storage at -80 degrees C for at least 3 months shows no loss of titre. The method shows no loss of sensitivity compared to previously described sample preparation methods. Deglycerolised Glycigel supernatants were found to be suitable for conventional anti-HIV-1 serological studies and loss of sensitivity only represented the dilution effect due to sample preparation. Application of the method as a means of storing samples frozen at the point of sampling and transporting them to a central laboratory for processing is demonstrated using samples taken from HIV-1-infected mothers and their babies.

Adult↗
PubMedDate not supplied

Adherence to antiretroviral therapy: appropriate use of self-reporting in clinical practice.

PURPOSE: This study investigated the factors that may affect adherence to antiretroviral therapy in people with HIV infection and compared the use of three self-report tools to determine client adherence. METHOD: A descriptive, cross-sectional study of 260 HIV-infected clients attending nine HIV outpatient centers in England was conducted using researcher-administered instruments. Self-reports of adherence were assessed using the Morisky Medication Adherence Scale (MMAS), Reported Adherence to Medication Scale (RAM), and the Patient Adjustment to Medication Scale (PAM). RESULTS: Univariate analysis of clients' self-reports indicated a number of associations with adherence. Significant associations with less adherent behavior identified by two or more self-report tools were the reported use of recreational drugs, p =.001; living alone, p =.041; feeling depressed, p =.02; being influenced by the media, p =.037; and lack of a close confidant, p =.037. Greater adherence was associated with clients reporting a positive mental attitude to HIV infection, p =.038. Principal component analysis (PCA) of each self-report tool identified two well-recognized constructs: intentional nonadherence and unintentional nonadherence. In addition, a third construct of following instructions was identified from PAM, a scale developed by the authors. Subsequent regression analysis failed to confirm the associations with adherence suggested by the univariate analysis. CONCLUSION: This study suggests that the design and use of self-report tools to identify client's adherence to complex antiretroviral regimens may need to measure individual constructs of adherence to accurately assess adherence behavior.

Adolescent↗