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Biomedical subjects

C J Roberts

Publications and source records attributed to C J Roberts.

At least 145 records · Page 8Linked to original sources
PubMed1986

Is biliary excretion of paracetamol significant in man?

The extent of biliary excretion of paracetamol and its principal metabolites was studied in 10 healthy adults. Duodenal intubation was performed approximately 12 h after an oral dose of 1 g paracetamol. Duodenal fluid was aspirated following intravenous cholecystokinin, and urine was collected for 12 h after dosing. The mean concentration of the cysteine and glucuronide conjugates in the bile was 253.7 +/- 39.0 micrograms ml-1 (s.e. mean) and 69.3 +/- 15.3 micrograms ml-1, respectively. The mean recoveries of the cysteine and glucuronide conjugates in the bile were 6.0 +/- 1.5 mg and 1.2 +/- 0.41 mg, respectively. The bile is an important route of elimination for the cysteine conjugate and accounts for 19.4 +/- 4.4% of the total excretion of the metabolite. The fate of the biliary excreted conjugates is not known, and needs further investigation.

Acetaminophen↗
PubMed1986

The distinction between worth and affordability: implications of costs and benefits for the allocation of health care resources.

There is an important distinction between worth and affordability which remains largely unrecognized. It is widely supposed that if an economic analysis shows that the benefits of a service exceed its costs, failure to fund it is irrational and inefficient. By means of a simplified model of a health care system, it is shown that although an excess of benefits over costs is a necessary precondition for providing a service, it is by no means sufficient. If society is to make the best use of its resources in health care, worthwhile services--those which make a social 'profit'--must be compared with other such services. Since the resources available to any health care system will always be limited, it is likely that not all services whose benefits exceed their costs can be afforded, because the budget has already been committed to those worthwhile services which yield higher benefits per unit cost.

Cost-Benefit Analysis↗
PubMed1986

Anti-ulcer drugs and intrinsic factor secretion.

Twelve healthy volunteers were randomly allocated to take two of the following treatments; cimetidine, misoprostol (a prostaglandin E1 analogue) and carbenoxolone, for two weeks. A further four subjects took ranitidine. Gastric aspirates were collected before and on the 14th day of therapy for each drug, and analysed for intrinsic factor concentration and total output. Both randitine and cimetidine inhibited pentagastrin stimulated output by 47% and 27% respectively in comparison to control, but had no effect on stimulated mean intrinsic factor concentrations. No changes were observed with misoprostol and carbenoxolone treatment.

Adult↗
PubMed1985

Can we afford screening for neural tube defects? The South Wales experience.

Clinical and financial gains and losses accruing from five different options for screening for open neural tube defects were estimated, based principally on the results of detailed monitoring of inputs and outcomes and of process costs in the South Wales Anencephaly and Spina Bifida Study. As well as estimating the overall clinical costs of a screening service it was shown that if the prevalence, including terminations, of open neural tube defects is between 1.25 and five per 1000 births the financial cost of avoiding the birth of a seriously handicapped child who would survive for more than 24 hours is in the range 9000 pounds- 54000 pounds depending on the option adopted and the prevalence of the condition in the target population. Prevalence is the biggest determinant of cost. The data should provide a basis for assessment and discussion of resource priorities in the National Health Service.

Anencephaly↗
PubMed1985

Effect of delayed esophageal transit on acetaminophen absorption.

Twenty patients awaiting cardiac catheterization swallowed a single tablet containing acetaminophen and barium sulfate. The first 11 subjects swallowed the tablet while supine; its progress down the esophagus was followed by fluoroscopy. In 10 of these subjects, transit of the tablet was delayed in the esophagus. The other nine subjects swallowed the tablet while standing; it entered the stomach immediately. The plasma concentration profile of acetaminophen was measured in all subjects. When there was delayed esophageal transit of tablets, the initial absorption of acetaminophen (measured as the AUC over the first 60 min) was lower than that after normal esophageal transit of tablets. The peak plasma acetaminophen concentration was also lower and occurred on average 70 min later when transit was delayed. These kinetic changes decrease the effectiveness of acetaminophen as an analgesic. We recommend that, to ensure rapid and complete drug absorption, patients be advised to swallow tablets with a large amount of water while standing.

Acetaminophen↗
PubMed1985

Induction of chromosome aberrations and cell killing in Syrian hamster fibroblasts by gamma-rays, X-rays and fast neutrons.

Chromosome aberrations were scored in BHK21 C13 Syrian hamster fibroblasts, exposed to 60Co gamma-rays, 250 kV X-rays, 15 MeV neutrons or neutrons of mean energy 2.1 MeV produced from the 9Be(d,n)10B reaction. The cells were irradiated in stationary phase, where they are concentrated in the G1 phase of the cell cycle. Within experimental uncertainty there was no detectable difference between the responses to 60Co gamma-rays and to 250kV X-rays. The r.b.e. for the production of dicentrics, based on the 'one-hit' component of response, was (5 +/- 2) for the 15 MeV neutrons and (12 +/- 5) for the 2.1 MeV neutrons. For each radiation, a graph of the proportion of cells without a dicentric, centric ring or acentric fragment corresponded closely to the survival curve for stationary-phase cells obtained in the same experiment.

Animals↗
PubMed1985

Epidemiology for medical students: a controlled trial of three teaching methods.

Medical students taking a course in epidemiology for clinical practice were taught by either lectures, small group seminars or self-learning packages. Examination performances were no different for the three groups, but self-perceived mastery of learning objectives, and satisfaction with the course were higher for students who received self-learning packages. Sixty per cent of self instruction students found the teaching method was successful compared with 37% of the seminar students and only 19% who received lectures. A combination of self-instructional package and seminar would seem to hold most promise for a workable and effective course.

Education, Medical, Undergraduate↗
PubMed1985

The natriuresis following oral administration of the calcium antagonists--nifedipine and nitrendipine.

Ten healthy individuals received in random order placebo, nifedipine 10 mg, nifedipine 20 mg, nitrendipine 10 mg and nitrendipine 20 mg as single oral administrations at weekly intervals. On the day before each treatment placebo was administered. Urine was collected for 6 h and then for 18 h after each administration. There was a significant increase in urine volume and sodium excretion after the drugs, but no change in potassium excretion. The effect was most evident in the 6 h after drug administration. The effect was no greater at the higher doses of either drug. A natriuretic-diuretic action of nifedipine and nitrendipine has been confirmed in man. The mechanism of the effect remains unclear.

Administration, Oral↗
PubMed1985

Should women at high risk of neural tube defect have an amniocentesis?

As part of an investigation into the practical problems of a maternal serum alphafetoprotein (AFP) neural tube defect (NTD) screening programme carried out in Mid Glamorgan, South Wales, between 1977 and 1979, obstetricians were recommended to refer women with high risk pregnancies directly for counselling, high resolution ultrasonography, and amniocentesis without first carrying out serum screening. Out of 15 687 pregnant women one-third attended too late to be screened. A total of 637 was classed as high risk, mostly at greater risk than 1 in 50 because of a previously affected pregnancy or an affected close relative. Compliance with recommended procedure was relatively low as many were screened. There were 10 pregnancies with a recurrence of NTD, of which one was not tested at all, two were not detected (one closed meningocele and one closed iniencephalic), and seven were detected and the pregnancies terminated. All the latter, as well as the iniencephalic, would have been detected from a serum AFP determination and a high resolution ultrasound scan alone. It is concluded that these investigations are sufficient for high risk pregnancies and that amniocentesis is not really cost effective or necessary unless either of these investigations is abnormal. As numbers in this study were small it is suggested that these conclusions should be tested in a larger study.

Amniocentesis↗
PubMed1985

Recurrent idiopathic pneumomediastinum.

A case is described of the rare syndrome of recurrent idiopathic pneumomediastinum which had been mistakenly diagnosed as recurrent spontaneous perforation of the oesophagus. The case illustrates the importance of distinguishing between pneumomediastinum and oesophageal rupture because of their markedly differing prognosis and management.

Adult↗
PubMed1984

Implementation of guidelines for the use of skull radiographs in patients with head injuries.

Guidelines formulated by the Royal College of Radiologists' Working Party on the Effective Use of Diagnostic Radiology were introduced into an accident-and-emergency department to determine their effect on the use of skull radiographs in patients with head injuries and on the number of admissions for observation. After approval by senior staff and substitution of the routine casualty record with a head-injury casualty card, the guidelines were distributed throughout the department, and seminars on the suggested use of skull radiographs were held for junior medical staff. The proportion of new accident-and-emergency attenders having skull radiographs fell by 51%. The average number of skull examinations carried out in the department decreased from 373 to 189 per month, but there was no increase in the number of patients with head injuries admitted for observation.

Adolescent↗
PubMed1984

Does unequal leg length cause back pain? A case-control study.

In a case-control study, in which a specially designed questionnaire and a "locating jig" were used to investigate the association between difference in lower limb length and other disproportion at or around the sacroiliac joints and the existence of chronic low back pain, no association was found. Chronic back pain is thus unlikely to be part of the short-leg syndrome.

Anthropometry↗
PubMed1984

The effects of oxytocin and vasotocin analogues on the responses of rat brainstem neurones to oxytocin.

The effects of microiontophoretically applied oxytocin on the firing rates of neurones in the rat caudal brainstem have been examined. Of the sample of 156 units recorded the firing rates of 33.3% were reduced and those of 21.2% were raised by microiontophoretically applied oxytocin, whilst the remainder were unaffected. The distribution of units facilitated by oxytocin tended to overlap with the distribution of oxytocin demonstrated immunocytochemically, whereas many units inhibited by oxytocin were in regions where no oxytocin was observed. Overall the excitatory but not the inhibitory effects of oxytocin could be blocked by oxytocin and vasotocin analogues with antagonist properties.

Animals↗