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Biomedical subjects

J H Stewart

Publications and source records attributed to J H Stewart.

At least 37 records · Page 2Linked to original sources
PubMed1995

Effect of changing the stillbirth definition on evaluation of perinatal mortality rates.

The perinatal mortality rate is widely used as a summary statistic for evaluating the effectiveness of perinatal care. Since October, 1992, it has been a legal requirement in England and Wales to register fetal deaths at 24-27 completed weeks of gestation as stillbirths (in addition to those after 28 weeks), thereby altering the definition of perinatal death. In a cohort analysis of all babies born to women resident in Wales during 1993, we assessed whether the revised definition of perinatal mortality rate more appropriately measures effectiveness of care. There were 36,793 births and 313 perinatal deaths (221 stillbirths, 92 early neonatal deaths). At 24-27 weeks' gestation there were 59 (39%) survivors and 93 deaths (52 stillbirths, 36 neonatal deaths [28 early, eight late], and 5 postneonatal deaths). 119 babies had a birthweight below 500 g; one survived and 24 were perinatal deaths. Of the 36 late neonatal deaths all were attributed to perinatally related events. Increased survival of infants at 24-27 weeks' gestation emphasises the importance of including all these infants in the perinatal mortality rate, but it would be a more useful measure of the effectiveness of perinatal care if it excluded babies below 500 g, and included late neonatal deaths.

Adult↗
PubMed1995

International renal-cell cancer study. II. Analgesics.

There has been concern about the role of analgesics in the development of renal-cell cancer, although a few studies have reported moderately elevated risks with regular or long-term use. In a large international case-control study of renal-cell cancer we examined, among other hypotheses, the effect of phenacetin-containing and of other types of analgesics: paracetamol (acetaminophen), salicylates (mainly aspirin) and pyrazolones (e.g., antipyrine or phenazone). Relative risks, adjusted for the effects of age, sex, body-mass index, tobacco smoking and study centre, were not significantly increased with intake of phenacetin, either when lifetime consumption was categorized at the level of > or = 0.1 kg or when subjects were subdivided further by amount. Nor were paracetamol, salicylates or pyrazolones linked with renal-cell cancer. No consistently increasing risks with consumption level was found. The lack of association was not altered by restricting analgesic use to that which occurred 5 or 10 years before the defined "cut-off" date or when analysis was restricted to exclusive users of a particular type of analgesic. Neither was the risk influenced by the rate of consumption or whether the consumption had occurred at a young age. Our study provides clear evidence that aspirin is unrelated to renal-cell cancer risk, and our findings do not support the hypothesis that analgesics containing phenacetin or paracetamol increase the risk, although the number of "regular" users and the amount of these types of analgesic consumed were too small to confidently rule out a minor carcinogenic effect of phenacetin and paracetamol.

Acetaminophen↗
PubMed1995

Value and quality of perinatal and infant postmortem examinations: cohort analysis of 400 consecutive deaths.

OBJECTIVES: To evaluate the contribution that perinatal and infant necropsy makes to clinical practice and to see how this might be influenced by the quality of the investigation. DESIGN: Cohort analysis, with data from the all Wales perinatal survey, of perinatal and infant deaths during 1993 of babies born to mothers usually resident in Wales. The clinicopathological classification of death based on clinical details was compared with the classification after necropsy. Similarly, cases in which necropsy yielded new information were identified. The quality of the necropsy was assessed by scoring six aspects of the examination. SUBJECTS: 400 consecutive deaths at 20 weeks of gestation to 1 year of age. MAIN OUTCOME MEASURES: Necropsy rate, effect of necropsy on clinicopathological classification, new information disclosed by necropsy, quality of necropsies, and the link between new information and quality of the necropsy. RESULTS: Necropsy was performed in 232 cases (58%). The clinicopathological classification was altered by necropsy in 29 cases (13%). New information was obtained in 60 cases (26%), and in 42 (18%) it disclosed the cause of death. The quality of necropsy was substantially higher when the main cause of death was detected than when nothing new was found. CONCLUSION: Necropsy is underused. Clinicians should be more positive about necropsies and realise how much clinically relevant information can be obtained from a good quality examination.

Autopsy↗
PubMed1995

Control of cancer-related pain with MS Contin: a comparison between 12-hourly and 8-hourly administration.

Nineteen cancer patients with chronic pain of moderate to severe intensity were randomized in a double-blind manner to 5 days of either 8-hourly or 12-hourly administration of controlled-release morphine (MS Contin, MSC), followed by the alternate schedule for 5 days. The control of pain, using an average dose of 303.4 +/- 254.4 mg/day of MSC, was good during both the 8-hourly and 12-hourly phases, and the mean daily pain intensity measured by visual analogue scale (VAS), pain relief (VAS), and global efficacy scores did not differ when compared by treatment schedule. The need for supplemental "rescue" morphine was infrequent and did not differ between treatment phases (8-hourly, 0.7 +/- 0.7 and 12-hourly, 0.6 +/- 0.6 doses per day, p = 0.6232). The overall frequency and severity of adverse events did not differ between the two dosing schedules. A majority of patients (67%) reported that they believed that 12-hourly dosing was a moderate or great advantage over 8-hourly dosing.

Cross-Over Studies↗
PubMed1995

Perinatal and infant postmortem examinations: how well are we doing?

AIM: To investigate the quality of perinatal and infant necropsies and assess the relation between the quality and value of this investigation in different outcome groups. METHODS: Cohort analysis of 540 deaths during 1993 of babies between 20 weeks' gestation and one year of age born to women usually resident in Wales. Cases were identified from the All Wales Perinatal Survey. Each case was assessed to establish whether the necropsy yielded clinically relevant information. The quality of necropsy was assessed by scoring aspects identified as being part of the necropsy. RESULTS: Necropsy was performed in 335 (62%) cases, and the report was available for assessment in 314 cases. The quality of necropsy was below the minimum standard in 46% (143/314) of cases. The highest quality necropsies were carried out on fetal deaths at 20 to 23 weeks' gestation (12% (10/85) below standard), compared with 65% (87/133) below standard on stillbirths and 68% (21/31) on sudden unexpected infant death. Overall, 42% (131/314) of necropsies were performed in a regional paediatric pathology centre including 88% (76/88) of fetal deaths, 23% (31/133) of stillbirths and 30% (29/96) of infant deaths. The quality score for the necropsy performed in a regional centre failed to achieve the minimum acceptable score in 8% (11/131) of cases compared with 72% (132/182) for those done elsewhere. The cause of death was detected by necropsy in 17% (52/314) of cases. The quality of necropsy was significantly higher when the cause of death was revealed than when nothing new was found. CONCLUSIONS: The overall quality of the perinatal and infant necropsy is poor. This is regrettable as valuable information can be revealed frequently by a good quality necropsy. Adherence to Guidelines for Postmortem Reports recently published by the Royal College of Pathologists should improve the situation.

Abortion, Spontaneous↗
PubMed1994

End-stage renal failure appears earlier in men than in women with polycystic kidney disease.

Age-specific and cumulative incidence rates calculated using data from the Australia and New Zealand Dialysis and Transplant Registry indicate that more men than women with polycystic kidney disease enter end-stage renal failure programs between the ages of 25 and 44 years and 65 to 74 years. As this autosomal dominant inherited condition is equally likely to occur in the two sexes, gender-related factors appear to modulate the susceptibility to renal failure in persons with polycystic kidney disease.

Adult↗
PubMed1994

Trends in the incidence of end-stage renal failure due to hypertension and vascular disease in Australia, 1972-1991.

BACKGROUND: Despite the known protective effects upon renal function of lowering blood pressure in primary chronic renal disease, diabetes and malignant hypertension, the number of patients entering dialysis and transplantation programmes with renal failure due to hypertension or vascular disease remains high. AIMS: To analyse the trends in incidence of arteriopathic end-stage renal failure. METHODS: Calculation of mean annual age- and sex-specific rates (by decade) and truncated age-standardised rates for entry into Australian end-stage renal failure programmes in the period 1972-1991. Statistical analysis by chi-squared test, assuming a Poisson distribution of cases. RESULTS: End-stage renal failure attributed primarily to hypertension or vascular disease fell to less than half its former level over the period of observation in persons aged 15-54 years. This change has occurred only in the diagnostic category 'malignant hypertension'. Trends in persons aged 55 years and over are more difficult to analyse because of changing criteria for entry into renal failure programmes, but there has been no indication of any fall in incidence. CONCLUSIONS: The aetiology and pathology of arteriopathic renal failure is diverse, with different patterns in young and old adults. The formerly common pathology in young adults is largely preventable by modern antihypertensive therapy, while arteriopathic renal disease in older persons is not.

Adolescent↗
PubMed1994

Trends in incidence of end-stage renal failure in Australia, 1972-1991.

Age-specific and cumulative incidence rates were calculated for entry into Australian end-stage renal failure programmes from 1972 to 1991, as a result of all causes, or from analgesic nephropathy, glomerulonephritis, hypertension and vascular disease, or diabetes. Three different trends were demonstrated. A rising recorded incidence of renal failure occurred throughout the period of observation in those aged 0-4 years (all causes) and in those aged 55 years and over (all categories, least in analgesic nephropathy) principally attributable to a falling fraction of patients not accepted for treatment. Falling incidence rates indicating a real reduction in the burden of disease were seen for analgesic nephropathy (at least up to the age of 64 years) and hypertension and vascular disease (only up to the age of 54 years). In young adults the unchanging incidence of renal failure due to all causes, glomerulonephritis and diabetes probably reflect nearly complete acceptance rates into end-stage renal failure programmes, and therefore approximate the true burden of disease. In end-stage renal failure, age-specific or age-standardized cumulative rates are required to distinguish rising or falling incidence of disease from trends due to changing medical practice.

Adolescent↗
PubMed1993

Different roles for phenacetin and paracetamol in cancer of the kidney and renal pelvis.

A population-based case-control study of kidney cancer was carried out in New South Wales using data from structured interviews with 489 cases of renal-cell cancer and 147 cases of renal pelvic cancer diagnosed in 1989 and 1990, together with 523 controls from the electoral rolls. This study showed that the risk of renal pelvic cancer was increased by phenacetin/aspirin compound analgesics (RR = 12.2; 95% CI 6.8-22.2) to a far greater extent than by paracetamol (RR = 1.3; 95% CI 0.7-2.4; not significant). There was a doubling of risk (RR = 2.0; 95% CI 0.9-4.4) in the highest tertile of paracetamol taken in any form compared with values for non-users of any type of analgesic. By contrast, the risk of renal-cell cancer appeared to be increased to a similar degree by phenacetin/aspirin compound analgesics (RR = 1.4; 95% CI 0.9-2.3) and paracetamol taken in any form (RR = 1.5; 95% CI 1.0-2.3). When both drugs were treated as alternative forms of the same risk factor, the risk was increased by 1.7 (95% CI 1.2-2.4). On this evidence, we postulate that phenacetin/aspirin compounds are weakly carcinogenic in the renal parenchyma through the metabolic conversion of phenacetin to paracetamol, and potently carcinogenic in the renal pelvis by different or additional pathways involving renal papillary necrosis. In addition, there is an indication of a weak link between paracetamol and renal pelvic cancer.

Acetaminophen↗
PubMed1993

Risk factors for kidney cancer in New South Wales. IV. Occupation.

In a population based case-control study of kidney cancer in New South Wales, data from structured interviews with 489 cases of renal cell cancer (RCC), 147 cases of renal pelvic cancer (CaRP), and 523 controls from the electoral roles were obtained about employment in certain industries or occupations, and exposure to particular chemicals chosen because of suspected associations with kidney cancer. A low level of education increased the risk for CaRP but not RCC. After adjustment for known risk factors, exposure to asbestos significantly increased the risk for RCC (relative risk (RR) = 1.62; 95% confidence interval (95% CI) 1.04-2.53). Working in the dry cleaning industry had a stronger link with CaRP (RR = 4.68; 95% CI 1.32-16.56) than with RCC (RR = 2.49; 95% CI 0.97-6.35). Working in the iron and steel industry doubled the risk for CaRP (RR = 2.13; 95% CI 1.04-4.39) whereas employment in the petroleum refining industry had a non-significant association with CaRP (RR = 2.60; 95% CI 0.88-7.63) and none with RCC.

Adult↗
PubMed1992

Risk factors for kidney cancer in New South Wales, Australia. II. Urologic disease, hypertension, obesity, and hormonal factors.

In a population-based case-control study of kidney cancer in New South Wales, Australia, data from structured interviews with 489 cases of renal cell cancer (RCC) and 147 cases of renal pelvic cancer (CaRP) diagnosed in 1989 and 1990, and 523 controls from the electoral rolls, confirmed the link between obesity and RCC. In addition, regular consumption of 'diet' pills independently increased the risk for this cancer. A diagnosis of hypertension at least two years before interview raised the risk for RCC, and regular use of beta-blockers, a class of antihypertensive drug, independently increased the risk for RCC and CaRP (risk ratio = 1.5-1.8). No independent effect was found for use of diuretics. Additional information provided by this study includes increased risks associated with kidney injury (RCC, CaRP)--possibly attributed to recall bias--and kidney infection (CaRP), as well as a nonsignificantly raised risk linked with kidney stones (RCC, CaRP) and a significantly reduced risk for RCC in persons giving a history of lower urinary tract infection. No significant association of RCC was found with hormonal factors (age at menarche or menopause; child-bearing; regular use of oral contraceptives or estrogens; hysterectomy or oophorectomy).

Adult↗
PubMed1992

Risk factors for kidney cancer in New South Wales--I. Cigarette smoking.

In a population-based case-control study of kidney cancer in New South Wales, data from structured interviews with 489 cases of renal cell cancer (RCC), 147 cases of renal pelvic cancer (CaRP) diagnosed in 1989 and 1990, and 523 controls from the electoral rolls confirmed an increased risk associated with cigarette smoking in both types of cancer. The risk among current smokers was consistently higher than among ex-smokers, and was nearly twice as great for CaRP than for RCC. Additional information provided by this study includes reduced risks following cessation of smoking within 12 years for CaRP, but only after 25 years for RCC. Starting to smoke before, rather than after, the age of 18 years is linked independently with almost twice the risk for CaRP, but does not affect the risk for RCC. No independent trend was found with number of cigarettes smoked per day.

Adult↗
PubMed1992

Understanding vascular ultrasonography.

The technology of imaging has progressed rapidly; thus, physicians must stay abreast of the principles of utilization and the interpretation of these new tests. Most of the information about this technology is presented in subspecialty literature that is not readily accessible or easily interpretable by nonspecialists. Herein we review the current literature on vascular ultrasonography and present the information in a simple, practical manner. The safety, utility, and accuracy of the ultrasound devices are delineated for the study of various vascular conditions.

Blood Vessels↗
PubMed1992

Theophylline and salbutamol improve pulmonary function in patients with irreversible chronic obstructive pulmonary disease.

To investigate the efficacy of bronchodilators in patients with irreversible chronic obstructive pulmonary disease (COPD), we conducted a double-blind, randomized, four-phase, crossover comparison between placebo, oral theophylline, inhaled salbutamol, and a combination of both drugs in 12 patients with stable COPD (mean age, 63 years) whose increase in forced expiratory volume in 1 s (FEV1) was less than or equal to 15 percent following 200 micrograms of inhaled salbutamol. Patients received two weeks of therapy with each of the test regimens. Both theophylline and salbutamol resulted in statistically significant improvement in FEV1, forced vital capacity (FVC), slow vital capacity (SVC), residual volume (RV), airway resistance (Raw), and maximum expiratory flow rate at 50 percent of vital capacity (V50). In most instances, there were no significant differences between theophylline and salbutamol. Combination therapy produced significantly greater improvement in FEV1, FVC, V50, Raw, and RV than either agent alone. The two drugs interacted in an additive fashion. Neither of the drugs, used singly, significantly reduced the severity or incidence of symptoms. The reduction in dyspnea and wheeze during combination therapy approached statistical significance (p = 0.06) and patient preference was significantly in favor of the combination regimen. None of the active treatments produced significantly more side effects than placebo. We conclude that theophylline and inhaled salbutamol produce significant, and approximately equal, improvement in pulmonary function in patients traditionally classified as suffering from "irreversible" COPD. The combination of theophylline and inhaled salbutamol generally results in additional improvement over that obtained with either drug used alone and this improvement is reflected by reduced symptomatology and treatment preference.

Administration, Inhalation↗