Search PubMed⌕ Search

Biomedical subjects

L Jones

Publications and source records attributed to L Jones.

At least 325 records · Page 18Linked to original sources
PubMed1989

Force matching by patients with unilateral focal cerebral lesions.

The performance of patients with unilateral frontal-, temporal- or fronto-temporal excisions was examined on an isometric force-matching task involving the coordination of forces generated by flexing the fingers. Patients with excisions from the right fronto-temporal cortex were significantly slower with both hands when performing this task using either two or three fingers, whereas the other patient groups tested were not impaired. This deficit in force coordination may result from an impairment in monitoring proprioceptive feedback or an inefficiency in programming the appropriate amount of force output.

Adolescent↗
PubMed1989

Characterization of Brucella canis protein antigens and polypeptide antibody responses of infected dogs.

The cytoplasmic protein antigens (CPAg) of Brucella canis were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of 35S-labeled polypeptides. Approximate molecular weights of the immunoreactive polypeptides were determined by migration patterns of the immunoprecipitated polypeptides after SDS-PAGE or Western immunoblotting of sera collected at various times after experimental infection of dogs. Polypeptides were specifically precipitated by sera of infected dogs, but not from the sera of normal or false-positive (seropositive, non-infected) animals. During the initial month after infection, proteins with molecular weight masses (MW) of approximately 18, 22, 31, 42 and 54 kDa were commonly recognized. A 20-kDa polypeptide was first recognized at 8-10 weeks after infection, but it was detected inconsistently after 6 months. Additional polypeptides detected from 2 to 12 months post-infection had MW of 22, 66-68 and, less regularly, 42, 60, 82, 100 and greater than 200 kDa. The polypeptides most consistently recognized in sera from B. canis-infected dogs had MW of 18, 22 and 68 kDa.

Animals↗
PubMed1989

Central corticotropin releasing factor reduces natural cytotoxicity. Time course of action.

Corticotropin-releasing factor (CRF) administered intracerebroventricularly produced both a rapid, greater than 50% reduction in splenic natural killer (NK) cytotoxicity and a prolonged elevation in plasma corticosterone levels. In the first 60 minutes following CRF, fivefold increases in corticosterone levels were associated with the suppression of NK activity. However, NK activity returned to control levels at later time points even though elevated plasma corticosterone levels persisted. These data augment the findings that central CRF reduces natural cytotoxicity and establish a time course for the effect in acutely treated rats.

Animals↗
PubMed1989

Respiratory health effects associated with ambient sulfates and ozone in two rural Canadian communities.

A cross-sectional epidemiological study investigating the respiratory health of children in two Canadian communities was conducted in 1983-1984 in Tillsonburg, Ontario, located in a region of moderately elevated concentrations of transported air pollutants, and in Portage la Prairie, Manitoba, situated in a low pollution area. There were no significant local sources of industrial emissions in either community. Seven hundred and thirty-five children aged 7-12 were studied in the first town and 895 in the second. Respiratory health was assessed by the measurement of the forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1.0) of each child, and by evaluation of the child's respiratory symptoms and illnesses using a parent-completed questionnaire. Sulfur dioxide (SO2), sulfate, and particulate nitrate levels were significantly higher in Tillsonburg than in Portage la Prairie (P less than 0.05), but nitrogen dioxide (NO2) and inhalable particles (PM10) differed little between the communities. Historical data in the vicinity of Tillsonburg indicated that average annual levels of sulfates, total nitrates, and ozone (O3) did not vary markedly in the 9-year period preceding the study. The results show that Tillsonburg children had statistically significant (P less than 0.001) lower levels of 2% for FVC and 1.7% for FEV1.0 as compared with children in Portage la Prairie. These differences could not be explained by parental smoking or education, the use of gas cooking or wood heating fuels, pollution levels on the day of testing, or differences in age, sex, height, or weight. The differences persisted when children with cough with phlegm, asthma, wheeze, inhalant allergies, or hospitalization before age 2 for a chest illness were excluded from analysis. With the exception of inhalant allergies, which occurred more frequently in Tillsonburg children, the prevalence of chronic respiratory symptoms and illnesses was similar in the two communities.

Air Pollutants↗
PubMed1989

Alcohol, cigarette smoking and breast cancer.

The results of two case-control studies of breast cancer which included questions on exposure to tobacco and alcohol are reported. One study included 998 hospital cases and a like number of matched hospital controls while the other included 118 cases identified during mammographic screening and a like number of matched normal screenees. Both studies used the same questionnaires and the same methods to obtain information. The results with regard to cigarette smoking differed between the two studies. The hospital-based study showed a decreased risk of breast cancer with increasing amounts smoked (relative risk for 15 or more cigarettes per day was 0.82, 95% confidence interval 0.60-1.13) while the screening study showed an increased risk (relative risk for 15 or more cigarettes per day was 2.90, 95% confidence interval 1.16-7.25). Evidence is presented that both results may be attributable to bias in the selection of cases and controls. It is concluded that reliable results on the relationship between smoking and breast cancer are only likely to come from population-based studies. These studies, in general, have found no relationship. Neither study produced any hint of an association between alcohol consumption and breast cancer. From this, it appears that bias in subject selection may not be such a significant factor in interpretation of studies of alcohol and breast cancer as it is in studies of smoking and the disease. A number of other difficulties in the interpretation of studies of alcohol and breast cancer are considered, including the great variation in the amount of alcohol consumed. It is concluded that the assertion that alcohol is a risk factor for breast cancer remains unproven.

Adult↗
PubMed1989

The effects of oral contraceptives and parity on ovarian cancer trends in women under 55 years of age.

Mortality from epithelial ovarian cancer is falling in women under 55 years of age in England and Wales. The decline does not appear to be a treatment effect nor to be attributable to changes in the rate of oophorectomy. Case-control studies have shown that high parity and oral contraceptive use are protective against the disease. We suggest that the decrease in mortality is compatible in timing and magnitude with exposure to oral contraceptives. No obvious effect on mortality attributable to parity was apparent in this analysis. Oral contraceptives may prove to be a widely acceptable means of preventing ovarian cancer, providing they do not increase breast cancer risk.

Adult↗
PubMed1989

Histopathology of breast cancer in young women in relation to use of oral contraceptives.

A detailed review was made of the histopathology of 227 tumours taken from 261 women under 45 years of age with breast cancer. The tumours were classified as follows: whether oral contraceptives had been used at any time; and whether oral contraceptives had been used before first term pregnancy. All analyses were adjusted for the effects of age. Overall, 201 (88.5%) of tumours were infiltrating ductal in type, 19 (8.4%) were infiltrating lobular, and seven (3.1%) were in situ ductal. Of the infiltrating ductal tumours, 28 (14%) were grade I 88 (44%) grade II, and 84 (42%) grade III. Various other tumour characteristics were also examined (per cent of carcinoma in situ, lymphatic permeation, necrosis, lymphoplasmocytic reaction and tumour edge). None of the histopathological features assessed showed any significant association with oral contraceptive use. Some characteristics of the areas of breast tissue adjacent to the tumours were also studied. The degree of cyst formation was considerably less pronounced in those using oral contraceptives before first term pregnancy than in those not doing so.

Breast↗
PubMed1989

Randomized controlled trial of anti-smoking advice by nurses in general practice.

Practice nurses are playing an increasingly prominent role in preventive care, including the provision of anti-smoking advice during routine health checks. A randomized controlled trial was designed to assess the effectiveness of anti-smoking advice provided by nurses in helping smokers to stop smoking. A total of 14,830 patients aged 16-65 years from 11 general practices completed a brief questionnaire on general health, including smoking status, at surgery attendance. The doctor identified 4330 smokers and randomly allocated 4210 to control or intervention groups. The doctor asked those in the intervention group to make an appointment with the practice nurse for a health check. The attendance rate at the health check was 26%. Smokers were sent follow-up questionnaires at one month and one year, and those who did not respond to two reminders were assumed to have continued to smoke. There was no significant difference in reported cessation between the intervention and control groups at one month or one year. However, there was a significant difference in the proportion of patients who reported giving up within one month and who had not lapsed by one year--0.9% in controls and 3.6% in the intervention group (P less than 0.01). Nevertheless, the effect of the nurse intervention itself may be small as the sustained cessation rate in attenders was only 42.4% higher than in non-attenders. The deception rate in reporting cessation, as measured by urinary cotinine, was of the order of 25%.

Adolescent↗
PubMed1989

Effect of transport conditions on the stability of biochemical markers in blood.

We examined the stability of lipids, carotenoids, alpha-tocopherol, and endogenous hormones in plasma prepared from whole blood that had been mailed to a central location for processing. Initially, to simulate transport conditions, whole-blood samples were stored in the laboratory, either at room temperature or cooled, for up to 72 h before processing. In the latter samples, lipid concentrations changed up to 1.4% per day, carotenoids up to -5.5%, and hormones up to 9.5%. In a second study, analyte concentrations in plasma from cooled whole blood mailed via overnight courier were compared with those from plasma that had been immediately separated, frozen, and mailed via overnight courier. Concentrations of cholesterol, high-density lipoprotein subfraction 3, apolipoprotein B, and retinol were stable. Overall, for each marker except estradiol, the between-person variation was at least twice the within-person variation. In a third study, at least 340 micrograms of DNA was recovered from 30 mL of cool-shipped whole blood. Our results indicate that shipping whole-blood samples by overnight courier is feasible for assay of several biochemical markers of interest in epidemiological research.

Adult↗
PubMed1989

Women and HIV disease.

Women are vulnerable to the acquired immunodeficiency syndrome (AIDS), and are now contracting the disease at a faster rate than men. However, many are ignorant of their potential risk of infection and it is only recently that the scientific community has begun to look at human immunovirus (HIV) infection in women. The media and statistical reporting still lag behind.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Protection of cattle against rinderpest with vaccinia virus recombinants expressing the HA or F gene.

Rinderpest is a highly contagious ruminant viral disease manifested by a rapid course and greater than 90% mortality. Infectious vaccinia virus recombinants were constructed that express either the hemagglutinin or the fusion gene of rinderpest virus. All cattle vaccinated with either recombinant or with the combined recombinants produced neutralizing antibodies against rinderpest virus and were protected against the disease when challenged with more than 1000 times the lethal dose of the virus.

Animals↗
PubMed1988

Performance on unimanual and bimanual tapping tasks by patients with lesions of the frontal or temporal lobe.

The performance of 151 patients with unilateral excisions from either the frontal or the temporal cortex and 60 normal subjects was examined on three motor tasks: (1) simple unimanual tapping; (2) spatially ordered unimanual tapping; and (3) bimanual tapping in which the movements of the two hands were out-of-phase. All patient groups were impaired with both hands on spatially ordered unimanual tapping. In contrast, only those patients with either left or right frontal-lobe lesions performed poorly on the bimanual tapping task. Our findings demonstrate that the frontal cortex plays a critical role in the co-ordination of arm and hand movements, particularly when different movements have to be performed simultaneously.

Adolescent↗
PubMed1988

Residual impairment in handgrip strength after unilateral frontal-lobe lesions.

The handgrip strength of 65 normal control subjects and 166 patients with unilateral frontal- or temporal-lobe excisions was assessed. Because of the known sex differences in strength, the results for the men and women were analysed separately. The grip strength of men with left frontal-lobe lesions was found to be within the normal range, but women with comparable excisions from the left frontal lobe had a residual impairment in strength on both hands. The men with right frontal-lobe lesions had a significant reduction in the strength of only the left hand, and the women in this group displayed a similar tendency. The deficits were interpreted in terms of a loss or disruption of input from the premotor area to the primary motor cortex.

Adolescent↗
PubMed1988

A prospective study of acute cerebrovascular disease in the community: the Oxfordshire Community Stroke Project 1981-86. 1. Methodology, demography and incident cases of first-ever stroke.

A prospective study of acute cerebrovascular disease in a community of about 105,000 people is reported. The study protocol combined rapid clinical assessment of patients with accurate diagnosis of the pathological type of stroke by CT or necropsy, whether or not they were admitted to hospital. The study population was defined as those people who were registered with one of 50 collaborating general practitioners (GPs). Referrals to the study were primarily from the GPs though, to ensure complete case ascertainment, hospital casualty and admission registers, death certificates and special data from the Oxford Record Linkage Study were also scrutinized. Six hundred and seventy five cases of clinically definite first-ever in a lifetime stroke were registered in four years yielding a crude annual incidence of 1.60/1,000 or 2.00/1,000 when adjusted to the 1981 population of England and Wales. The age and sex specific incidence rates for first stroke showed a steep rise with age for both sexes. The odds of a male sustaining a first stroke were 26% greater than those of a female. Ninety one per cent of patients were examined in a median time of four days after the event by a study neurologist and 88% had cerebral CT or necropsy.

Adolescent↗