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Biomedical subjects

V Seagroatt

Publications and source records attributed to V Seagroatt.

At least 55 records · Page 3Linked to original sources
PubMed1992

Trends in registered incidence of oesophageal and stomach cancer in the Oxford region, 1974-88.

In the Oxford region 8,903 residents with oesophageal or gastric cancers were registered by the Oxford Cancer Registry between 1974 and 1988. For most of this time the Registry's practice was to code all adenocarcinomas of the oesophagus as adenocarcinomas of the cardia of stomach. There was a significant increase over time in the registered incidence of adenocarcinoma of the cardia, no appreciable change in the incidence of oesophageal cancers registered as such, and a decline in registered incidence of cancers of the stomach other than cardia.

Adolescent↗
PubMed1992

Twin peaks, extramarital conceptions, and virgin births: is there a connection?

The trends in British twin and higher multiple birth rates inside and outside marriage from 1938 to 1989 were reviewed for evidence of the probable impact of the use of ovulatory stimulants. After adjustment for maternal age monozygotic twin rates within marriage rose to a significant excess (of 12%) over those outside during the last two decades; a similar increase of higher multiple births within marriage to a significant excess (of 50%) over those outside was also seen for 1980-9. The dizygotic twin rate within marriage exceeded that outside in 1989 for only the second time in 50 years, as the difference in rates narrowed in the last decade. It is concluded that ovulation induction and techniques of assisted conception are apparently more available to the married, with a stronger effect on higher multiple birth rates than on dizygotic twin rates. Monozygotic twin trends support the suggestion that part of the infertility treatment regimen also promotes zygote splitting.

England↗
PubMed1992

Time spent in hospital by children as a health care indicator: inter-district comparisons.

It has been widely recommended that children should be admitted to hospital only if treatment cannot be provided at home, and that durations of hospital stay should be minimized. We have used record linkage to calculate a statistic which is not yet commonly available, the total time spent in hospital by children per year, and have compared this between six districts in the Oxford Region. Hospitalization rates for children who stayed a total of two days or less per year in hospital increased over time; rates for children who stayed more than two days declined. Mean and median total days spent in hospital varied between districts but, in absolute terms, the differences were small at less than one day's difference between districts per year per child admitted. Inter-district variation decreased over time, although the variation in use of day case care which remained suggests that some districts could still do more work in this fashion.

Adolescent↗
PubMed1991

Elective total hip replacement: incidence, emergency readmission rate, and postoperative mortality.

OBJECTIVES: To report the incidence of elective total hip replacement and postoperative mortality, emergency readmission rates, and the demographic factors associated with these rates in a large defined population. DESIGN: Analysis of linked, routine abstracts of hospital inpatient records and death certificates. SETTING: 10 hospitals in six districts in Oxford Regional Health Authority covered by the Oxford record linkage study. SUBJECTS: Records for 11,607 total hip replacements performed electively in 1976-85. MAIN OUTCOME MEASURES: Incidence of operation, postoperative mortality, relative mortality ratios, and incidence of emergency readmission. RESULTS: NHS operation rates increased over time from 43 to 58 operations/100,000 population. Variation in operation rates between districts reduced over time. Operation rates were on average 25% higher in women than men. There were 93 deaths (11/1000 operations) within 90 days of the operation and 208 emergency readmissions (28/1000 operations) within 28 days of discharge. Postoperative mortality and emergency readmission rates increased with age. No significant trend with time was found. Mortality in the 90 days after the operation was 2.5-fold higher (1.9 to 3.0) than in the rest of the first postoperative year. This represented an estimated excess of 6.5 (4.2 to 8.8) early postoperative deaths/1000 operations. Most deaths were ascribed to cardiovascular events. Thromboembolic disease was the commonest reason for emergency readmission. CONCLUSIONS: The pronounced increase in operations in districts with initially low rates suggests a trend towards greater equity in the local provision of NHS hip arthroplasty. The early postoperative clusters of deaths attributed to cardiovascular disease and of readmissions for thromboembolic disease suggest that there is scope for investigating ways of reducing the incidence of major adverse postoperative events.

Adult↗
PubMed1991

Use of psychiatric services by patients in a general hospital.

OBJECTIVE: To identify physical disorders associated with increased rate of use of psychiatric services. DESIGN: Retrospective analysis of routine abstracts of general hospital inpatient records linked with those of psychiatric care, for inpatients with physical disorders with possible psychiatric associations and for controls. SETTING: Oxfordshire health district. SUBJECTS: Inpatients aged 15-64 years discharged from general hospitals during 1975-85 with a diagnosis among 14 selected diagnostic groups (including potentially life threatening conditions, chronic disabling diseases, and non-specific symptomatic conditions) and control inpatients with acute conditions. MAIN OUTCOME MEASURES: Observed and expected numbers of patients receiving psychiatric care. RESULTS: Observed use of psychiatric services before and after index admission was close to that expected for controls. For most other diagnoses the observed use was significantly increased in the year preceding and that subsequent to the admission. For four diagnostic groups it was significantly greater in the year after admission than in that before (acute myocardial infarction (ratio before to after 2.17, 95% confidence interval 1.5 to 3.3), cancer (2.05, 1.7 to 2.5), diabetes mellitus (1.89, 1.4 to 2.9), and chest pain (1.78, 1.3 to 2.4)). During four years after the admission the use of psychiatric services was significantly higher than in the general population for nonspecific symptomatic conditions (observed/expected: abdominal pain 1.7, chest pain 2.0, and headache 4.2), cirrhosis of the liver (10.4), and fractures in road accidents and other fractures (1.3, 1.6). CONCLUSIONS: More patients with certain physical conditions used psychiatric services. Alternative methods of service delivery may be needed, especially for disabling chronic physical illness, alcohol related disorders, and non-specific symptomatic conditions.

Adolescent↗
PubMed1990

Relation between general practices' outpatient referral rates and rates of elective admission to hospital.

OBJECTIVE: To examine the variation in rates of admission to hospital among general practices, to determine the relation between referral rates and admission rates, and to assess the extent to which variations in outpatient referral rates might account for the different patterns of admission. DESIGN: A comparison of outpatient referral rates standardised for age and sex and rates of elective admission to hospital for six specialties individually and for all specialties combined. SETTING: 19 General practices in three districts in Oxford Regional Health Authority with a combined practice population of 188 610. MAIN OUTCOME MEASURES: Estimated proportion of outpatient referrals resulting in admission to hospital, extent of variation in referral rates and admission rates among practices, and association between admissions and outpatient referrals. RESULTS: Patients referred to surgical specialties were more likely than those referred to medical specialties to be admitted after an outpatient referral. Overall, the estimated proportion of patients admitted after an outpatient referral was 42%. There were significant differences among the practices in referral rates and admission rates for most of the major specialties. The extent of systematic variance in admission rates (0.048) was similar to that in referral rates (0.037). Referral and admission rates were significantly associated for general surgery; ear, nose, and throat surgery; trauma and orthopaedics; and all specialties combined. For most specialties the practices with higher referral rates also had higher admission rates, casting doubt on the view that these practices were referring more patients unnecessarily. CONCLUSION: Rates of elective admission to hospital vary systematically among general practices. Variations in outpatient referral rates are an important determinant of variations in admission rates.

England↗
PubMed1989

A collaborative study to establish the International Reference Reagent for hepatitis B vaccine containing plasma-derived hepatitis B surface antigen.

A collaborative study was conducted to establish a suitable international reference reagent for hepatitis B vaccine for use in immunogenicity assays. The limiting dilution required to induce antibodies in 50% of the test animals was determined for the proposed international reference reagent and three other plasma-derived hepatitis B vaccines. The minimum antigenic dose of these preparations varied widely (100-fold range) between laboratories. However, the expression of potencies of vaccines relative to the proposed International Reference Reagent reduced the variation between laboratories to within a 10-fold range. The reference reagent is intended for use in assays of hepatitis B vaccines in mouse (or guinea-pig) immunogenicity studies. For products made by different procedures, clinical trials in humans are necessary to establish a correlation between the immunogenic potency in animals and man.

Drug Stability↗
PubMed1989

Do referral rates vary widely between practices and does supply of services affect demand? A study in Milton Keynes and the Oxford region.

Two commonly held beliefs about referral rates were investigated in this study: first that demand for services is determined by supply and secondly that there is wide variation between general practices in their referral rates. All referrals to specialist outpatient clinics were recorded during two 11-week periods by general practitioners in eight practices in the new town of Milton Keynes and in 17 practices elsewhere in the Oxford region. During the first period, only a limited outpatient service was available in the new town; for many specialist services, people had to be referred to hospitals outside the district. Referral rates from Milton Keynes were very similar to those from the rest of the region. By the second period the range of specialist facilities available locally had expanded considerably with the opening of the new district general hospital and during this period there was a statistically significant but rather small increase in referral rates from Milton Keynes. Variation in referral rates between general practices within each geographical group was greater than that between the two groups. Overall, there was about a three-fold variation between general practices in outpatient referral rates which is considerably less than that commonly thought to exist.

Delivery of Health Care↗
PubMed1988

Standardization of rye-grass pollen (Lolium perenne) extract. An immunochemical and physicochemical assessment of six candidate international reference preparations.

Six candidate extracts of Lolium perenne (rye-grass) pollen have been studied in 6 laboratories using a variety of immunochemical and physicochemical techniques. Radioallergosorbent test inhibition, crossed immunoelectrophoresis, crossed radio-immunoelectrophoresis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis combined with immunoblot, thin-layer isoelectric focusing and enzyme-linked immunosorbent assay inhibition were used to evaluate each of the coded extracts. The source materials were also studied for identity and possible contamination by light microscopy. On the basis of these data, the Rye-Grass Working Party recommended to the Steering Committee of the Allergen Standardization Subcommittee of the International Union of Immunological Societies that the extract coded C be chosen as the candidate international reference preparation.

Allergens↗
PubMed1986

The effects of purified components of Bordetella pertussis in the weight gain test for the toxicity testing of pertussis vaccines.

The effects of highly purified preparations of three Bordetella pertussis components--pertussis toxin (PT), lipopolysaccharide (LPS) and filamentous haemagglutinin (FHA)--were examined in the mouse weight gain test, a toxicity test for pertussis vaccine. When these components were administered alone, PT enhanced initial weight gains of the mice, LPS produced an initial weight loss and FHA had no detectable effect on the weights of the mice. However, testing the components in combinations revealed that the effect of PT and LPS together was not simply the sum of their individual effects. This combination generally produced lower weights than LPS alone, particularly in the later stages of the test.

Animals↗
PubMed1986

RAST inhibition: a collaborative study on its suitability and reproducibility for the assay of cocksfoot pollen extracts.

The suitability and reproducibility of the inhibition mode of the radioallergosorbent test (RAST) as a method for the assay of allergen extracts was examined in a collaborative study involving seven laboratories. Participants assayed five coded extracts of cocksfoot grass (Dactylis glomerata) pollen, including three batches from one manufacturer, both by a common method and by their local methods of RAST inhibition. For the versions of RAST inhibition employed in this study the estimates of relative potencies of the extracts were in agreement. Further, when laboratories used their local methods, the inter-laboratory variation in potency estimates was similar to that found when laboratories used the common method. It was concluded that RAST inhibition has a useful role in the assessment of the potencies of allergen extracts, and of the consistency of serial batches of extracts from individual manufacturers.

Allergens↗
PubMed1986

Single radial immunodiffusion assays for the standardization of the antigenic content of rabies vaccines.

The method currently recommended for the assay of rabies vaccine potency is a mouse protection test, the NIH test. It is widely accepted that the estimates of potency obtained in such tests are imprecise. We have applied the single radial immunodiffusion (SRD) technique to the assay of the glycoprotein antigen, the major protective antigen of the rabies virion. In this paper we have summarized the results of an international collaborative study, in which SRD was shown to give reproducible estimates of glycoprotein content. In addition the use of SRD in assessing the stability of rabies vaccines is discussed.

Animal Testing Alternatives↗
PubMed1986

Principles of biological standardization and the conduct of collaborative studies to establish international standards.

Principles of biological standardisation, based on the use of international standards, are discussed. Procedures are outlined for checking that a material has the properties required of a standard ie uniformity, stability and suitability to serve as a measure for biological activity. Particular consideration is given to the work involved in collaborative studies which are carried out to assess the suitability of a candidate standard to serve as a yardstick for the measurement of the biological activity of test samples likely to be assayed against it.

International Cooperation↗
PubMed1985

A collaborative study on the first international standard of Dermatophagoides pteronyssinus (house dust mite) extract.

A collaborative study was carried out to assess the suitability of a preparation to serve as the International Standard for Dermatophagoides pteronyssinus (house dust mite) extract. The proposed international standard of D. pteronyssinus, two additional freeze-dried extracts, and a commercially available skin testing solution were tested in the study. Nineteen laboratories in 11 different countries participated. The assay methods used included RAST inhibition, crossed immunoelectrophoresis/crossed radioimmunoelectrophoresis, isoelectric focusing, quantitative skin testing, and various other methods for assessing total allergenic activity. In addition, six laboratories measured the quantity of antigen P1, and three laboratories measured antigen DpX in each of the preparations. On the basis of the results from this study, the World Health Organization established the preparation as the International Standard for D. pteronyssinus extract with an assigned unitage of 100,000 IU per ampule. The units refer both to the total allergenic activity of the ampule and to that of the individual allergens, such as P1 and DpX.

Allergens↗