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Biomedical subjects

I Sutherland

Publications and source records attributed to I Sutherland.

At least 37 records · Page 2Linked to original sources
PubMed1991

On the risk of infection.

The epidemiological importance of the annual risk of infection with tubercle bacilli has been recognized only recently. Calendar trends in the risk and its association with age have been assessed from tuberculin test data. In The Netherlands, this information has been used to estimate the development of clinical tuberculosis following infection or re-infection. The calendar trend in the risk of infection is the best index of improvement or deterioration in a community. The difficulties of assessing it are outlined.

Age Factors↗
PubMed1990

Electrochemistry of galvanic couples between carbon and common metallic biomaterials in the presence of crevices.

In vitro experiments were conducted upon some common metallic biomaterials and carbons, both isolated or forming galvanic couples, in a cell specially designed for crevice corrosion studies. The alloys examined were AISI 316L stainless steel, Ti6AI4V and Co-Cr-Mo. The types of carbon were glassy carbon and carbon fibre-reinforced carbon. The surface modifications were evaluated by SEM, AES and ESCA-XPS analyses. AISI 316L stainless steel suffered localized corrosion in open-circuit experiments whilst the other materials remained unattacked. Galvanic currents between metal-carbon couples were measured by zero resistance ammetry. The carbon-metal area ratio was 1:1. The results showed that 316L stainless steel and the Co-Cr-Mo alloy were prone to accelerated corrosion, whilst the Ti6AI4V alloy remained unattacked. The galvanic corrosion currents were also predicted using mixed potential theory from polarization curves obtained for each material. The experimental and theoretical values showed good agreement for the stainless steel and Co-Cr-Mo alloy. Long-term immersion tests with the same couples showed that the only metal not to suffer degradation was the Ti6AI4V alloy.

Alloys↗
PubMed1990

An assessment of the value of BCG vaccination in England and Wales.

The scheme for BCG vaccination at about age 13 years in England and Wales was introduced in 1953. The coverage of the scheme is now 75%, and the efficacy of BCG has been 75-80% throughout, but the incidence of tuberculosis in young white adults has been decreasing steeply since 1950. The benefits of the scheme have consequently been decreasing equally rapidly in recent years. Discontinuation of the scheme would lead to some additional cases of tuberculosis but would not greatly increase the very small current risk of tuberculosis developing in the unvaccinated 13-years old.

Adolescent↗
PubMed1989

The effects of the scheme for BCG vaccination of schoolchildren in England and Wales and the consequences of discontinuing the scheme at various dates.

The aims of this paper were to estimate the numbers of tuberculosis notifications in young white adults which will be prevented in the next 25 years by the schools BCG vaccination scheme, and to assess the numbers of additional notifications if the scheme were to be discontinued. Assuming that in the white ethnic group in England and Wales the decline in tuberculosis notification rates (8-10% per year for ages less than 45 years) and efficacy of BCG vaccination (75-80%) are maintained, it is estimated that the scheme for BCG vaccination of schoolchildren with its present coverage will prevent 217 notifications in those aged 15-29 years in 1993, 119 in 1998, and 69 in 2003. The epidemiological consequences of stopping the BCG in schools scheme, whenever this occurs, would be a substantial slowing of the rate of decline of tuberculosis notifications, confined almost entirely to the 15-29 years age group, for a period of about 15 years, after which the steeper decline would resume. If the scheme stopped at the end of 1991 the annual number of additional notifications would slowly increase to a maximum of just over 80 about 15 years later, and then decrease. For stopping at the end of 1996 the maximum annual number of additional notifications would be about 50.

Adolescent↗
PubMed1988

Changes in tuberculosis notification rates in the white ethnic group in England and Wales between 1953 and 1983.

Since the early 1960s notification rates for tuberculosis in England and Wales for the whole population have been influenced by high rates in certain ethnic groups. Using data based on country of birth from the British (Thoracic and) Tuberculosis Association surveys of 1965 and 1971, and based on ethnic origin from the Medical Research Council surveys in 1978/79 and 1983, rates for the white ethnic group have been estimated at those four times, and compared with the published rates for the whole population in 1953, when only a very small proportion was of non-white ethnic origin. Between 1953 and 1983 the notification rate for the white ethnic group fell from 122.2 to 11.3 per 100,000 for males, an annual decline of 7.7%, the corresponding rates for females being 90.1 and 5.8, an annual decline of 8.8%. The greatest annual declines occurred between 1953 and 1965, 9.4% for males and 11.2% for females. The annual declines in the most recent period, 1978/79 to 1983, were 6.9% for males and 7.3% for females. In both sexes the decline was greatest in the 15-24 year age group and least in the oldest age group, and this has led to a change in the age pattern of annual notification rates. The highest rates in both sexes occurred in young adults in 1953 but in the oldest age groups in 1983. There is however no evidence of any cohort experiencing an increase in notification rate with increasing age.

Adolescent↗
PubMed1987

Effectiveness of BCG vaccination in England and Wales in 1983.

The effectiveness of BCG vaccination, at about age 13 years, in the prevention of tuberculosis at ages 15-24 years in England and Wales in 1983, has been determined by the same method as in two previous surveys in 1973 and 1978. In 1983, the tuberculosis notification rate among those vaccinated in the schools' scheme was 3.30 per 100,000, compared with an estimated rate of 13.20 per 100,000 among those who were tuberculin negative and not vaccinated in the scheme. The protective effectiveness of BCG vaccination at ages 15-24 years in England and Wales in 1983 is thus estimated as 75%; the estimated efficacy in the white ethnic group is closely similar, namely 76%. The estimated efficacy of BCG at ages 15-19 and 20-24 years in the three surveys, both in the white ethnic group and in the entire cohort, has been compared with that found in the Medical Research Council's controlled trial of tuberculosis vaccines which began in 1950. There is no evidence of any decrease in the protective efficacy of BCG vaccination between the four cohorts of young adults, which span a total period of 29 years. However, there were steep decreases between the cohorts in the annual notification rates for the white ethnic group; these decreases occurred in the BCG vaccinated and in the tuberculin negative unvaccinated groups, as well as among those found tuberculin positive (and not vaccinated) in the schools' scheme. It is concluded that the level of protective efficacy of BCG vaccination at ages 15-24 years is high, and has remained unchanged since the start of the BCG in schools' scheme. However, as the tuberculosis notification rate in young adults has decreased steeply throughout this period, and is continuing to decrease, the benefits to be expected from the BCG in schools' scheme will decrease equally rapidly.

Adolescent↗
PubMed1987

A study of the use of maternity and child welfare clinics in case-finding for pulmonary tuberculosis in Kenya.

This investigation is the seventh in a series of case-finding studies in Kenya. It explores the potential value of questioning mothers attending maternity and child welfare (M & CW) clinics to identify tuberculosis suspects (individuals aged 6 years or more with a cough for 1 month or more or hemoptysis) living in their households. The study was carried out in all the eight M & CW clinics in two divisions (populations 86,000 and 112,000) of two different districts. The mothers were asked to give a standard letter, which explained the possible importance of a chronic cough, to each suspect they identified and invited the suspect to attend the district hospital chest clinic. Each suspect attending the clinic was entered in a special register and two sputum specimens were collected. For those who failed to attend, the specimens were collected at a home visit. Of the total of 342 suspects living in the two study areas who were registered at the M & CW clinics during 1 year, 261 were identified by the mothers but 19 denied having received the standard letter. The remaining 81 had not been identified by mothers but had attended the M & CW clinics on their own initiative. Of the 242 suspects who received the letter, 89 (39%) attended the hospital chest clinic, 74% within a week of the letter being issued from the M & CW clinic. The main reasons given for not attending the hospital chest clinic by the remaining suspects were financial or because their cough had improved or disappeared. Sputum was collected from 238 suspects and examined bacteriologically: in six (2.5%) it was positive for tubercle bacilli on smear and culture and in a further two (0.8%) the sputum was positive on culture only. Of those attending the hospital chest clinic 2.9% were smear- and culture-positive and 4.7% were culture positive. This method of case-finding has yielded disappointing results, for only 4% of the estimated annual incidence of smear-positive cases was detected.

Adult↗
PubMed1987

Cardiac anti-ischemic effect of metoprolol: role of beta-blockade within the ischemic region.

The distribution of metoprolol and atenolol into ischemic and nonischemic myocardium was studied in anesthetized dogs, pigs, and cats. The beta-blockers were administered intravenously after coronary artery occlusion. Metoprolol was found to be significantly more efficiently distributed to the ischemic myocardium than atenolol in all three species. To investigate the functional implications of this difference in tissue distribution, the anti-ischemic effects of the two beta-blockers were studied in the 2-h period following coronary artery occlusion in anesthetized cats, in which heart rate was kept at a constant level. In this model, metoprolol (0.3 mg.kg-1 + 0.15 mg.kg-1.h-1) was found to attenuate or delay the developing ischemic process. This is shown by its significant reduction of (a) the decline of CK activity in ischemic myocardium, (b) the ST elevation in a precordial ECG lead, and (c) the decrease of arterial pressure and cardiac output. In contrast to metoprolol, atenolol (0.3 mg.kg-1 + 0.15 mg.kg-1.h-1) caused no significant anti-ischemic effect in this cat model. The difference in the effectiveness of the two drugs can most probably be explained by their differential distribution in the ischemic heart. Furthermore, the anti-ischemic effect of metoprolol shows that the presence of a beta-blocker in ischemic left ventricular myocardium can favorably affect the early phase of developing infarction.

Adrenergic beta-Antagonists↗
PubMed1984

Induction of ovulation with pulsatile luteinising hormone releasing hormone.

Ovulation was successfully induced with luteinising hormone releasing hormone in 28 women with hypothalamic amenorrhoea who had failed to respond to treatment with clomiphene. Luteinising hormone releasing hormone was administered in a pulsatile manner with miniaturised automatic infusion systems. The rate of ovarian follicular maturation, as monitored by serial pelvic ultrasonography, was similar to that observed in spontaneous cycles. Endocrine assessment by serial measurement of gonadotrophin, oestradiol, and progesterone concentrations showed hormone concentrations to be within the normal range. Intravenous treatment was required in only two patients, the remainder responding satisfactorily to subcutaneous infusion. All patients conceived within six cycles of treatment, and only one multiple pregnancy occurred.

Adult↗
PubMed1984

Changes in tuberculosis notification rates in ethnic groups in England between 1971 and 1978/79.

Between special surveys in 1971 and 1978/79 the estimated annual tuberculosis notification rate for males in England fell from 30.5 per 100 000 to 22.6 per 100 000 (a decline of 3.8% per year). For females the rate fell from 18.4 per 100 000 to 15.8 per 100 000 (1.9% per year). In each survey the lowest rates were those for the white ethnic group born in the United Kingdom. The highest rates, some more than 50 times as great, occurred in immigrants from the Indian sub-continent (Indian or Pakistani/Bangladeshi). The rates for immigrants from the West Indies were 3 to 4 times as great as than those for the white group. The most rapid reductions in rate between the surveys, of about 10% per year, occurred in West Indian immigrants of both sexes and in Pakistani/Bangladeshi male immigrants. The rate for Pakistani/Bangladeshi females fell by 6.5% per year. For whites born in the U.K. the annual rate of decline was 5.1% in each sex. There was very little change for Indian immigrants of either sex. Between the surveys, continued immigration of groups from the Indian subcontinent with high notification rates considerably slowed the decline in notification rate for the whole population. The steep downward trend in notification rate for the white ethnic group may be expected to continue, but changes in the other ethnic groups are more difficult to assess because they are influenced by so many uncertain factors. In addition, the trends in the non-white ethnic groups born in the United Kingdom cannot yet be ascertained, but will become of increasing importance.

Bangladesh↗
PubMed1984

Study of case-finding for pulmonary tuberculosis in outpatients complaining of a chronic cough at a district hospital in Kenya.

This investigation is the fifth in a series of case-finding studies in Kenya. It explores the potential for case-finding by the identification of persons with suspected tuberculosis (persons with a cough for 1 month or more) through careful screening of general outpatients attending a district hospital. Of 601 suspects identified among 20,756 new outpatients attending hospital during a period of 11 wk, 5.6% were considered by an independent assessor to have active pulmonary tuberculosis (2.2% with sputum positive on both smear and culture, 1.2% on culture only, and 2.2% negative sputum but radiographically active lesions). A further 2.0% were considered to have inactive tuberculosis. This method of case-finding appears to be uniformly effective within a radius of approximately 9 miles of the hospital, becoming less effective outside this range. There were certain important diagnostic pointers. There was an excess of tuberculosis cases in males, in those with weight loss, in those with a history of cough of less than a year, in those with a history of hemoptysis, and in those 35 yr of age or older. This investigation provides additional support to our previous studies, which demonstrated serious problems of case-finding in the peripheral health units and suggests that unless the infrastructure of primary health care at the periphery can be improved, the policy should be to diagnose tuberculosis in the district hospital and to operate a simple referral system for persons with suspected tuberculosis from the periphery.

Adolescent↗
PubMed1983

The risk of tuberculous infection in The Netherlands from 1967 to 1979.

Estimates of the annual risks of tuberculous infection in the Netherlands from 1910 to 1966 were made by Stýblo et al. [1] from tuberculin surveys in recruits and schoolchildren. The risk decreased particularly steeply after about 1940 (the annual decrease in log risk was about 13%), and forward projections of the risk were made on this basis to 1980. Tuberculin test results in male recruits and in secondary or primary schoolchildren between 1966 and 1979 have now been used, alone and in conjunction with the earlier material, to estimate the trend in the risk of tuberculous infection in the Netherlands up to 1979, and to study the sex and age patterns in the risk. The risk of infection has continued to decrease steeply with calendar year in the Netherlands. Among the recruits the log risk, estimated only from the data from 1966 to 1979, decreased annually by 10.4%, compared with the estimate of 13.7% from the earlier data from 1956 to 1966; this difference is non-significant. Analysis of the complete data on schoolchildren from 1956 to 1979 shows a decrease in their log risk of infection of 15.0% each calendar year. The risks of infection were similar for boys and girls up to age 10, but were higher for boys than for girls (by 10.2%) during adolescence. In addition there was an increase in log risk of about 6.1% for each year of age up to age 20. According to this analysis, the annual risks of tuberculous infection in 1979 in the Netherlands were estimated to be 6, 9, 12, and 16 in 100 000 boys aged 5, 10, 15 and 20 years respectively, and 6, 9, 11 and 15 in 100 000 girls.

Adolescent↗
PubMed1983

The persistence of tuberculin sensitivity following oral BCG vaccination in The Netherlands.

Certain anomalies in the tuberculin test results in Netherlands schoolchildren in the late 1960s and in recruits a few years later are shown to have arisen from the persistence of tuberculin sensitivity in some of the 10 000 newborn children who were given oral BCG vaccine in the early 1950s. More than 90% of these oral BCG vaccinations were given in 1950 or 1951 in Amsterdam, Delft or Hilversum, but because of the absence of a scar or any record, individuals who were vaccinated cannot now be distinguished from the much larger numbers of unvaccinated subjects. The cohorts of Dutch children born in 1950 and 1951 showed excess positivity, compared with earlier and later cohorts, when tuberculin tested at different ages in adolescence and as army recruits, and this was especially noticeable among current residents in these three cities. It is estimated that less than 10% of those given oral BCG vaccine in the Netherlands in 1950 or 1951 showed positive reactions at ages 12 and 13, but about 20% did at age 16, and about 45% at age 18. A review of data on tuberculin sensitivity several years after intradermal BCG vaccination in the newborn or in young children suggests that sensitivity persists in only a relatively small proportion for a long period (in perhaps about 45% after 7 years and less after a longer period), unless boosted by intervening tuberculin tests. The present data on oral BCG vaccination in the newborn conform to the same pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗