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Biomedical subjects

J Pickering

Publications and source records attributed to J Pickering.

At least 37 records · Page 2Linked to original sources
PubMed1994

Chloroquine chemoprophylaxis in children during peak transmission period in Ethiopia.

A randomized controlled trial of the effect of chloroquine prophylaxis versus placebo on the occurrence of clinical malaria was carried out in 1988 among children aged 1-14 in the Awash Rift Valley of central Ethiopia. At the time of the study, chloroquine resistance had not been reported from this area. Two thousand children were randomly allocated to either chloroquine phosphate (5 mg base kg-1) or a multivitamin tablet. Treatment and weekly follow-up were carried out for 10 weeks during the peak malaria transmission season. There was no difference between chloroquine and placebo groups in the occurrence of at least one episode of clinical malaria, in smear positivity in those who remained free of attacks until the end of the study period, or in the prevalence of splenomegaly at the end of the study period. It is concluded that chloroquine prophylaxis is ineffective in preventing at least one clinical attack of malaria in children in this area.

Adolescent↗
PubMed1993

Exercise, fibrinogen, and other risk factors for ischaemic heart disease. Caerphilly Prospective Heart Disease Study.

OBJECTIVE: To examine the associations between physical activity and a wide range of risk factors for ischaemic heart disease including fibrinogen concentration and viscosity. DESIGN: Cross sectional evidence from the 2398 men aged 50-64 years in the Caerphilly Prospective Heart Disease Study. METHODS: Validated questionnaires were used to quantify energy expenditure on leisure activities and to grade activities related to occupation. Risk factors for heart disease examined included blood pressure, lipids, fibrinogen, and plasma viscosity. Possible confounding variables included smoking, employment, and prevalent heart disease (angina, previous myocardial infarction, and electrocardiographic evidence of ischaemia). RESULTS: Fibrinogen concentration was lower by 0.24 g/l and viscosity by 0.026 cP in the third of men who were most active in leisure activities (about 0.25 x 1 SD). A weak positive relation was found with high density lipoprotein cholesterol, but none with total cholesterol or fasting glucose concentrations or blood pressure. Triglyceride concentrations seem to be substantially lower in the most active men, although the evidence for this is not consistent. Work related activity showed relation with the lipid concentration but not with the haemostatic tests. CONCLUSIONS: Leisure activities of all levels seem to affect haemostatic and lipid factors beneficially. These effects correspond to a difference in the risk of heart disease for an active man and a sedentary man of at least 7% or 8%. Fasting triglyceride concentrations have already been shown to be strongly predictive of heart disease in this cohort of men, and the effect of exercise on this factor is also likely to confer benefit.

Blood Viscosity↗
PubMed1993

Antimalarial drug utilization by women in Ethiopia: a knowledge-attitudes-practice study.

A survey was undertaken between December 1991 and February 1992 to assess the knowledge, attitudes, and practices with respect to malaria of 300 women from six randomly selected rural communities in central Ethiopia. A total of 85% were able to recognize one or more of the common symptoms of the disease; however, the modes of transmission were generally misunderstood and only 23% believed that transmission could be prevented. More women preferred to obtain antimalarials from government clinics rather than from private drug shops, mission clinics, unofficial suppliers of injections, open markets, or from leftover sources. Under-5-year-olds were identified as the most malaria-vulnerable group and given priority for treatment; severity of illness was the principal determinant in seeking treatment. Decisions about treatment were generally made jointly by both parents. Knowledge about the transmissibility of malaria decreased with increasing distance from a health unit (odds ratio: 0.48; 95% confidence interval: 0.27, 0.86). A logistic regression analysis indicated that literacy and village were the most important variables associated with knowledge about preventing malaria.

Adolescent↗
PubMed1993

Are reminder stickers effective in reducing immunization dropout rates in Addis Ababa, Ethiopia?

A field trial to assess the effectiveness of a reminder sticker in reducing immunization dropout rates was conducted in two districts of Addis Ababa between 14 October 1991 and 31 January 1992. A total of 703 children were entered into the study. The study population was randomly divided into intervention and control groups. The intervention group received a reminder sticker and the control group did not. All other services were identical. A baseline interview documented the socio-demographic and maternal characteristics potentially related to immunization services utilization and revealed no statistically significant differences between the two groups. The dropout rates were 7.3 and 13.3% in the intervention and control groups respectively. This difference is clinically and statistically (P < 0.01) significant. Therefore, it is concluded that the reminder sticker is effective in reducing immunization dropout rates. Further investigations under operational conditions are recommended prior to the routine introduction of stickers into the immunization services.

Costs and Cost Analysis↗
PubMed1991

Cooperative foraging, productivity, and the central limit theorem.

The central limit theorem is applied to group foraging to show an automatic and universal benefit to group living. This may explain the paradoxical inverse correlation between group size and per capita brood production in primitively eusocial insects and why only one of the five major lineages of social insects contains species that revert to solitary habit.

Journal Article↗
PubMed1991

HIV infection in an Ethiopian prison.

HIV-1 antibody was detected in 6.0 percent of prisoners in an Ethiopian prison. HIV-1 seropositivity was strongly associated with positive VDRL status (RR = 3.7) and recent admission to prison (RR = 3.5). Seropositive prisoners were more likely to have prostitute contacts. No correlation was found between seropositivity and number of sexual contacts, long-term sex partners, or dental extractions. HIV-1 infection in this area may be of recent origin and the high prevalence may reflect rates in the surrounding community.

Adult↗
PubMed1990

[Declining trend in gonorrhea in The Netherlands; significance for the AIDS epidemic?].

Since 1981, the notified incidence of gonorrhoea has been decreasing in The Netherlands, thus preceding the onset of the AIDS epidemic. The declining trend of gonorrhoea and its underlying reasons are investigated. The reporting patterns may be influenced not only by the disease incidence but by other factors as well. Therefore the national notification gonorrhoea data over the period 1976-1988 are analysed in conjunction with detailed data from the two sexually transmitted diseases (STD) clinics in Amsterdam. Since 1983 the decline in gonorrhoea has been further reinforced by a dramatic decrease in gonorrhoea among homo/bisexual men, presumably as a result of behavioural changes because of AIDS. There is less evidence of massive behavioural changes among heterosexuals. The incidence of repeat infection among the gonorrhoea population in Amsterdam increases and may suggest that sexually highly active individuals continue to put themselves at risk of STDs, despite the educational campaigns with respect to the AIDS epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Declining gonorrhoea rates in The Netherlands, 1976-88: consequences for the AIDS epidemic.

The national notification gonorrhoea data are analysed over the period 1976-88 in conjunction with detailed data from the two STD clinics in Amsterdam in order to get an insight into the underlying reasons for the downward trend of gonorrhoea in The Netherlands. Possible effects of variations in reporting bias, seasonality, resistance against antibiotics, and sexual behaviour on gonorrhoea rates are considered. In 1981 the incidence of gonorrhoea started to decrease, thus preceding the onset of the AIDS epidemic in The Netherlands. Since 1983 the decline in gonorrhoea further accelerated and has been most apparent among homo- and bisexual men, presumably as a result of behavioural changes because of AIDS. There is less evidence for massive (AIDS related) behavioural changes among heterosexuals. The increasing percentage of gonorrhoea patients with recurrent episodes of STDs in Amsterdam may suggest that highly sexually active individuals continue to put themselves at risk of STDs and persist in acquiring and transmitting gonorrhoea.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Fenofibrate for the treatment of type IV and V hyperlipoproteinemias: a double-blind, placebo-controlled multicenter US study.

The results of a randomized, double-blind, placebo-controlled multicenter trial of fenofibrate in the treatment of type IV/V hyperlipoproteinemia are reported. Ten study centers in the United States recruited 147 adults with a history of type IV or V hyperlipoproteinemia. After a six- to 12-week dietary stabilization period and a four-week placebo period, patients whose 12-hour fasting total plasma triglyceride levels ranged from 350 to 1,500 mg/dl were continued in the study; 55 patients with levels of 350 to 499 mg/dl were placed in group A and 92 with levels of 500 to 1,500 mg/dl in group B. Patients in each group were randomly assigned to receive 100 mg of fenofibrate or placebo three times daily for eight weeks. In both groups A and B fenofibrate-treated patients showed statistically significant reductions in levels of total cholesterol, very-low-density lipoprotein cholesterol, total triglycerides, and very-low-density lipoprotein triglycerides, and significant increases in high-density lipoprotein cholesterol; patients in group B also showed a significant increase in low-density lipoprotein cholesterol levels. Sixteen of the 75 fenofibrate-treated patients and 11 of the 72 placebo patients reported adverse events that were potentially drug related; most of these were gastrointestinal and a few reported musculoskeletal and skin reactions. It is concluded that fenofibrate is an effective and safe agent in the treatment of type IV/V hyperlipoproteinemia.

Adolescent↗
PubMed1989

Cigarette smoking in Cree Indian school children of the James Bay region.

A survey of cigarette smoking habits of Cree Indian school children in the James Bay region of northern Quebec was carried out. Out of 689 questionnaires completed by students in grades 6 through Secondary V (approximately ages 11 through 18), 13.2% were nonsmokers, 35.4% were exsmokers, and 51.4% were current smokers. 65% of the smokers were daily smokers and they averaged 7 cigarettes per day. Factors positively associated with being a current smoker were age, female sex, having a mother who smoked, and having a best friend who smoked.

Adolescent↗
PubMed1983

A game-theoretical model of parasite virulence.

The evolution of parasitic reproductive rates, relative infectiousness and severity of disease are considered using a game-theoretical model in which parasites compete within hosts. Each parasite's fitness is assumed to be directly proportional to the product of its reproductive rate (lambda) and the length of time (T) over which it reproduces. An increase in a parasite's reproductive rate is assumed to increase its host's disease-induced mortality rate (alpha) and consequently, through host death, to decrease T. By maximizing the total number of propagules that individuals produce with respect to their individual reproductive rates, we show that competitors within a host may be favored by natural selection to reproduce at rates below their maximum potential rates. Whether competitors behaving with such restraint can coexist at a Nash equilibrium is shown to depend on the functional form of alpha (lambda) and on the number of competitors within a host. While an individual's restraint benefits its within-host competitors through increased host longevity, the model does not invoke group selection. In the model, selection favors an individual's restraint when such behavior increases the individual's total number of propagules. Concurrent increases in the absolute and relative fitness of an individual's within-host competitors can be consequences of such individual selection.

Animals↗
PubMed1980

Protein-calorie malnutrition and cutaneous anergy in hemodialysis maintained patients.

In 52 unselected patients maintained in intermittent hemodialysis, protein calorie malnutrition was present in 10 patients (19%). Complete cutaneous anergy to four intradermal skin antigens. (Candida, tuberculin, Streptokinase-dornase, and mumps) and failure to respond to contact sensitization to dinitrochlorobenzene was present in 60% of the patients. No correlation between cutaneous anergy and protein calorie malnutrition could be demonstrated.

Adult↗
PubMed1976

The perception of familiar stimuli.

A model is described for the processing of word-like (regular) and non-word-like (irregular) letter strings in a situation where either type of string may occur. It is proposed that each type of string is processed by specialised routines which are deployed contingently on an initial decision about the regularity of an item. Three experiments involving word/nonword and same/different responses investigate how the processing of a string is affected by the brief exposure of a prior string. It is shown that processing is interfered with less when both strings are of the same degree of regularity than when they are not. The model is revised and extended in the light of the results obtained as well as some theoretical considerations.

Cognition↗