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Biomedical subjects

R Jackson

Publications and source records attributed to R Jackson.

At least 217 records · Page 12Linked to original sources
PubMed1995

Naturally occurring tuberculosis caused by Mycobacterium bovis in brushtail possums (Trichosurus vulpecula): II. Pathology.

The gross and microscopic lesions due to Mycobacterium bovis infection are described in 73 brushtail possums (Trichosurus vulpeculu) from population studies and from 11 terminally ill possums. Subcutaneous lesions were suppurative in nature, often discharging through sinuses to the exterior. Histologically, the smallest lesions comprised focal aggregations of macrophages with angulated cytoplasmic boundaries occasionally containing acid-fast organisms. Larger lesions were pyogranulomatous, with extensive necrosis, caseation and large numbers of intra- and extra-cellular acid-fast organisms. Few multinucleate giant cells were seen and fibroplasia was rare. Mineralisation was recorded in tuberculous lymph nodes from only two possums. Histological evidence of haematogenous and lymphatic spread was seen in some cases.

Journal Article↗
PubMed1995

Naturally occurring tuberculosis caused by Mycobacterium bovis in brushtail possums (Trichosurus vulpecula): III. Routes of infection and excretion.

Mycobacterium bovis was cultured from nine of 25 (36%) tracheal washings but not from any of 38 urine and 38 faecal samples from tuberculous possums cross-sectionally sampled from the wild. One of three tracheal washings, one of three urine samples and one of three faecal samples from terminally ill possums were culture-positive. The respiratory route is implicated as the major route of excretion of Mycobacterium bovis from naturally infected possums in horizontal transmission. Tuberculosis was observed in two young possums and was evidence of probable pseudo-vertical transmission via the respiratory route or ingestion of milk. Discharging fistulae were present in 22 of 71 (31%) cross-sectionally sampled tuberculous possums and were associated with relatively advanced disease. Although the frequent involvement of superficial lymphocentres in early stage disease could not be explained satisfactorily, the respiratory route was implicated as the main route of infection from indirect evidence.

Journal Article↗
PubMed1995

A study of the environmental survival of Mycobacterium bovis on a farm in New Zealand.

Mycobacterium bovis organisms absorbed on cotton ribbons were placed in different natural habitats on a farm in New Zealand. Mycobacterium bovis was not re-isolated from ribbons placed on pasture after 4 days. Survival on ribbons was longest in brushtail possum dens, where the maximum period of survival in dens was less than 7 days in summer and greater than 14 days but less than 28 days in winter and spring. The maximum period of survival on a forest floor was intermediate between pasture and dens less than 4 days in summer and greater than 14 days but less than 28 days in winter. The overall probability of survival was influenced by season and was shortest in summer and longest in spring and winter. Survival time increased as minimum daily temperatures decreased. These studies showed there was a relatively short period of survival of M. bovis outside hosts and support a conclusion that environmental contamination of pasture, particularly in summer months, may be relatively unimportant in the epidemiology of tuberculosis in cattle, deer and possums.

Journal Article↗
PubMed1995

Evaluation of three serological assays for the diagnosis of Mycobacterium bovis infection in brushtail possums.

Three serological tests for the diagnosis of Mycobacterium bovis infection were evaluated on 29 possums (Trichosurus vulpecula) with tuberculosis and on 100 possums from a tuberculosis-free area. An indirect ELISA using M. bovis culture filtrate as the antigen had a sensitivity of 45% and a specificity of 96%, while an indirect ELISA using a M. bovis specific antigen (MPB70) had a sensitivity of 21% and a specificity of 98%. A blocking ELISA which utilised a monoclonal antibody against MPB70 had a sensitivity of 28% and a specificity of 99%. Combination of the test results of the three ELISAs resulted in an increase in sensitivity to 51% and a decrease in specificity to 93%. A previous study has shown that possums experimentally infected with M. bovis produced cellular responses to M. bovis antigens relatively early in the infection, but these responses decreased in the terminal stages of the disease. In contrast, analysis of serological responses in the current study from sequentially collected sera of possums experimentally and naturally infected with M. bovis showed that antibody was first detected late in the disease.

Journal Article↗
PubMed1995

Volume preloading is not essential to prevent spinal-induced hypotension at caesarean section.

We have compared the protective effect of 1000 ml preload with 200 ml preload of crystalloid solution, administered during the 10 min before spinal anaesthesia was induced, in 60 healthy women with no fetal compromise undergoing elective Caesarean section. The spinal anaesthetic was managed identically in both groups by an anaesthetist who was unaware of the volume of fluid administered. A prophylactic infusion of ephedrine 60 mg in Hartmann's solution 500 ml was given according to maternal arterial pressure. Hypotension was defined as > or = 30% reduction from baseline or < 90 mm Hg, and was treated by i.v. ephedrine bolus doses. There was no significant difference in ephedrine requirements between the two groups or in the incidence, severity or duration of hypotension: 10 women in the 1000-ml group, five episodes lasting > or = 3 min compared with nine women in the 200-ml group, four lasting > or = 3 min. There was no difference between neonates in each group. We have now abandoned the routine of preloading before regional anaesthesia.

Adult↗
PubMed1995

Do cardiovascular disease risk factors predict all-cause mortality?

BACKGROUND: The purpose of this study is to describe associations between a number of standard cardiovascular risk factors and all-cause mortality. METHOD: Mortality data were collected for a randomly selected cohort of 1029 New Zealand men aged 35-64 years, followed up over a 9-year period. A proportional hazards regression model was used to estimate the relative risks (RR) for all-cause mortality associated with a number of cardiovascular risk factors. RESULTS: In all, 96 deaths occurred over the 9-year period, of which 50% were due to cardiovascular causes. All-cause mortality was positively associated with cigarette smoking (age-adjusted RR = 2.01, 95% CI:1.15-3.53, current versus never), systolic blood pressure (age-adjusted RR = 2.18, 95% CI:1.23-4.44, upper versus lower tertile), and body mass index (age-adjusted RR = 1.59, 95% CI:0.94-2.66, upper versus lower tertile) and inversely associated with high density lipoprotein (HDL)-cholesterol (age-adjusted RR = 0.45, 95% CI:0.25-0.80, upper versus lower tertile). All-cause mortality was only weakly associated with serum total cholesterol (age-adjusted RR = 1.19, 95% CI:0.70-1.99, upper versus lower tertile), and there was no evidence of a U-shaped relationship for this risk factor. There was an inverse association between all-cause mortality and socioeconomic status (age-adjusted RR = 1.70, 95% CI:1.03-2.80, lower versus upper). Light alcohol consumption was associated with reduced all-cause mortality (age-adjusted RR = 0.63, 95% CI:0.37-1.05, light versus teetotal), but this benefit did not persist for alcohol consumption above about three standard drinks per day. CONCLUSIONS: The findings of this study indicate that the standard cardiovascular risk factors are likely to have a beneficial impact on all-cause mortality as well as cardiovascular disease in middle-aged and older men.

Adult↗
PubMed1995

Use and safety of acellular pertussis vaccine among adult hospital staff during an outbreak of pertussis.

During May and June 1993, 10 patients and 5 members of the clinical staff at a hospital in California were diagnosed with Bordetella pertussis infection. In addition to erythromycin prophylaxis, 630 (48%) of 1330 staff members received a half dose of acellular pertussis vaccine with tetanus and diphtheria toxoids (DTaP). To identify side effects of the vaccine, a questionnaire was completed by 344 (54%) of 630 vaccinated staff. Side effects were reported by 117 respondents (34%); 64 were classified as mild (local reaction at injection site) and 50 as moderate (systemic complaints or local reaction resulting in limitation of arm movement). Three vaccinees (< 1%) reported missing 1 or more days of work because of their symptoms. Local reactions at the injection site occurred in 100 (29%), systemic symptoms in 38 (11%), and limitation of arm movement in 18 (5%). This study indicates that use of half dose of DTaP in adults appears safe and should be considered as an adjunct to chemoprophylaxis during institutional outbreaks.

Adult↗
PubMed1995

What are the implications for the community of the discrepancy between the theory and practice of BP control?

Epidemiological data suggest that the lower the BP, the lower the cardiovascular risk. This is true across a broad range of BP levels, including those considered 'normal'; more than half of all cardiovascular events attributed to raised BP occur when DBP is < or = 95 mmHg. The belief that lowering BP too far is harmful is based on the hypothesis of a J-shaped relationship between BP and risk of cardiovascular disease. The weight of evidence now clearly suggests, however, that the J-shaped curve is not a consequence of treatment, but of underlying cardiovascular dysfunction that reduces BP and increases morbidity and mortality. Current prospective observational data give no evidence of a threshold BP below which there is no further reduction in cardiovascular disease risk. The average BP reductions in randomised trials are 5-6 mmHg (diastolic) and 10-12 mmHg (systolic), which would be expected to reduce the incidence of stroke by 35% and of coronary heart disease by 21%. If average BP reductions were doubled, prospective observational studies suggest the cardiovascular risk would be reduced by a further 15-20%.

Antihypertensive Agents↗
PubMed1995

The composition of Roman medical instrumentaria as an indicator of medical practice: a provisional assessment.

Archaeological evidence, in the form of sets of instruments and doctors' tombstones, can provide pointers towards the varied roles of Greco-Roman medical personnel. A number of recent discoveries have prompted a consideration of the range of instruments in those instrumentaria which are believed to be complete. The variety of instruments, and the presence, absence and relative numbers of certain types can shed light particularly on the range of medical and surgical interventions that could have been attempted. Thus, while the composition of most of the complete instrumentaria implies that their users encompassed all three branches into which medicine was traditionally divided--dietetics, drugs and surgery--the composition of other sets suggests that they were used by practitioners who specialised in a single operation or a restricted range of treatments, as, for example, dentistry, lithotomy and eye diseases.

Archaeology↗
PubMed1995

Driveway-related child pedestrian injuries: a case-control study.

OBJECTIVES: To examine risk factors for driveway-related child pedestrian injuries. DESIGN: A community based case-control study. SETTING: The Auckland region of New Zealand. PARTICIPANTS: Cases (n = 53) were children killed or hospitalized as a result of a driveway-related pedestrian injury, in the Auckland region over a period of 2 years and 2 months. Controls (n = 159) were an age-matched random sample of the child population of the Auckland region. RESULTS: The absence of physical separation of the driveway from the children's play area was associated with a threefold increase in the risk of driveway-related child pedestrian injury (OR = 3.50; 95% CI 1.38, 8.92). Children living in homes with shared driveways were also at significantly increased risk (OR = 3.24; 95% CI 1.22, 8.63). The population attributable risk associated with the absence of physical separation of the driveway from the children's play area was 50.0% (95% CI 24.7, 75.3). CONCLUSION: The fencing of residential driveways as a strategy for the prevention of driveway-related child pedestrian injuries deserves further attention.

Accidents, Home↗
PubMed1995

An interview with Dr. Ronald Jackson, DDS, on esthetic inlays and onlays. Interview by Dr. Gary Severance.

Dr. Ronald Jackson is a graduate of West Virginia University School of Dentistry. After a general practice residency and service with the Navy in London, England, he began private practice in Middleburg, VA, in 1976. His practice emphasizes comprehensive restorative and cosmetic dentistry. In an effort to identify leaders in the field of restorative and cosmetic dentistry for Signature readers, I asked Dr. Jackson to meet with me to discuss his experience with inlays and onlays as well as his efforts to educate patients about the different types of restorations available to them. Dr. Jackson has published many articles and lectures extensively on esthetic inlays and onlays. He has twice been a featured speaker at the annual meeting of the American Academy of Cosmetic Dentistry and is scheduled to present at the 1995 meetings of the American Academy of Esthetic Dentistry and the American Society for Dental Aesthetics. Dr. Jackson is an accredited member of the AACD and holds visiting faculty appointments to the postgraduate programs in esthetic dentistry at the State University of New York at Buffalo and Baylor University Schools of Dentistry. He is on the editorial boards of three dental publications and consults to a number of dental manufacturers in the area of new product development and clinical testing of materials.

Aluminum Silicates↗
PubMed1994

Validity of self-reported hospital admission in a prospective study.

This study examines the validity of self-reported hospital admission data obtained by telephone interview from a sample of 563 participants in a follow-up study in Auckland, New Zealand. The personal recall of hospital admissions over a 4-year period between 1988 and 1991 was compared with a national computerized record of all hospital admissions. Only two admissions were recalled by participants but not recorded on the hospital record. However, the study found significant underreporting of admissions by participants. Of those participants who could be contacted, 58% recalled all their admissions recorded on the computerized database. Additionally, 26% recalled some of the admissions, and 16% recalled none of the admissions. The age, sex, and social class status of the participants did not appear to significantly influence recall ability. A greater proportion of "first" admissions (68%) was recalled than that of "readmission" (45%). Follow-up studies that rely on similar methods for collecting self-reported hospital admission data may significantly underestimate admission rates, particularly those of readmissions for the same condition.

Adult↗
PubMed1994

Translational regulation. Y the message is masked?

Much mRNA in Xenopus oocytes is translationally dormant for months until meiotic maturation and fertilization. This masking has been found to be coupled to transcription and mediated by the Y-box protein FRGY2.

Animals↗