Biomedical subjects
M Rees
Publications and source records attributed to M Rees.
Hepatic resection for colorectal secondaries.
A postal survey of consultant surgeons in England and Wales was carried out to assess current attitudes towards screening for and treatment of hepatic metastases from primary colorectal carcinoma. The results showed that pre-, intra- and postoperative screening were inadequate. There was no consensus as to which patients would benefit from major hepatic resection for colorectal liver secondaries. Fewer than one-third of potentially operable patients underwent liver surgery.
Short-term prediction of HIV infection and AIDS: a critique of the Working Group's Report to the Department of Health.
The Report of the Working Group on the Short-Term Prediction of AIDS/HIV (the Cox Report) is reviewed mainly to assess its calculations of the numbers of people in England and Wales who are infected with the human immunodeficiency virus (HIV). Two main methods are used in the report to estimate this total--the direct method and the back projection method. The direct method estimates the number of people infected with HIV by attempting to specify the numbers of people in various at-risk groups, and the percentage infected in those groups. Of particular significance are the estimates given for male homosexuals. The Cox Report suggests that between 4.0% and 4.7% of the male population aged between 16 and 59 are homosexual, and that between 1.9% and 4.5% of these are HIV antibody-positive. The basis on which these estimates are made is not substantiated by the Report, and it is quite possible that the upper limit given for HIV prevalence in male homosexuals represents an understatement of the actual number by a factor of 2.5 or more. The back projection method estimates HIV prevalence from the numbers of cases of the acquired immunodeficiency syndrome (AIDS) and the incubation function, the relationship between HIV infection and the probabilities of AIDS in each of the years following infection. Using this method the Cox Report fails to produce results that are in accordance with our knowledge of how the epidemic developed during the 1980s. As a consequence of this the various calculations of numbers of HIV antibody-positives to 1987 given in the Cox Report are all almost certainly underestimates.(ABSTRACT TRUNCATED AT 250 WORDS)
Effect of rate-adapting atrioventricular delay on stroke volume and cardiac output during atrial synchronous pacing.
The need to adjust atrioventricular delay relative to pacing rate in atrial synchronous pacemakers was assessed in eight subjects treated for complete heart block (mean age 61 +/- 3.4 years). First, an inverse relationship between heart rate and PR interval was confirmed in two groups of healthy subjects and one group of patients recovering from myocardial infarction. Due to the limitations of the available pacemakers this relationship could not be precisely reproduced. Subjects with pacemakers performed an initial exercise test on a bicycle ergometer to determine heart rate response; this information was used in part 2 to program atrioventricular delay relative to heart rate. During a second exercise test, a rate-adapting atrioventricular delay was compared to a constant atrioventricular delay of 200 ms at matched heart rates. Cardiac output was measured noninvasively by impedance cardiography. The results of part 1 showed an abnormal pattern in the response of stroke volume to exercise in seven subjects. Part 2 results demonstrated no significant difference (P greater than 0.05) between a rate-adapting atrioventricular delay and a constant delay of 200 ms for heart rate, stroke volume, cardiac output, blood pressure or Borg scale. A trend towards increased stroke volume with a rate-adapting atrioventricular delay was observed. Stroke volume was 13% larger with a rate-adapting atrioventricular delay of 125 ms at a heart rate of 125 beats/min. These results suggest that subjects with atrial synchronous pacemakers have a variable stroke volume response to exercise. It appears that in these subjects the ability to increase heart rate is the key factor for raising cardiac output during exercise.
Use of the ultrasonic aspirator in splenic preservation.
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Chromosome 5 allele loss in familial and sporadic colorectal adenomas.
DNA extracted from familial and sporadic colorectal neoplasms was compared with constitutional DNA using a range of hypervariable locus specific probes to assess the extent of allele loss during conversion to malignancy. Chromosome 5 allele loss was observed in 23% of carcinoma samples, as previously found by others. However, we have been able to show for the first time loss of the D5S43 locus on chromosome 5 in adenomas from three patients, two of whom had the precancerous condition adenomatous polyposis coli (APC). These results suggest significant genetic changes involving chromosome 5 are occurring in benign adenomas. Probes for chromosome 1 (loci D1S7 and D1S8) and for chromosome 7 (loci D7S21 and D7S22) revealed no notable alterations in the adenoma samples. Complete loss of alleles for loci on chromosome 7 was not observed in carcinomas but reduced intensity of one parental allele was found in three specimens one of which was known to have multiple copies of this chromosome. Results using probes for chromosome 1 suggest that deletion of the D1S7 or D1S8 loci is not a common event in colorectal carcinogenesis. Loss of chromosome 5 alleles in adenomas from APC patients provides evidence in support of Knudson's hypothesis.
Long-term recurrence patterns following proximal gastric vagotomy.
Two hundred and forty-two consecutive patients were prospectively followed up following elective proximal gastric vagotomy (PGV) for duodenal, pyloric or prepyloric ulceration. There was no operative mortality and no case of lesser curve necrosis. Five to 15 years follow-up have been completed. One hundred and eighty-three patients were assessable (80% of survivors) and 29 of 33 symptomatic patients attended for endoscopy. Fourteen recurrent ulcers had been diagnosed previously and six new recurrences were diagnosed, giving a total recurrence rate of 11%. Seven of these were transient/innocuous and 13 (7%) were chronic/malevolent recurrences. The majority (70%) of recurrences occurred in the first 5 years of follow-up and only one recurrence occurred later than 10 years' follow-up. More than half (56%) of the operations were performed utilizing Burge intra-operative testing and 44% without Burge testing. No difference in recurrence rates was apparent between these two groups. In seven patients with pyloric or prepyloric ulceration, three (43%) developed a chronic recurrence. PGV is a safe, surgical treatment for duodenal ulceration, offering acceptable recurrence rates and a very low mortality and low incidence of side-effects. The majority of recurrences occur early in the follow-up period. Burge intra-operative testing provides no clear reduction in recurrence rates. PGV should not be used for pyloric or prepyloric ulceration.
Congenital pilonidal sinus of the nose.
The aetiology of pilonidal disease, which occurs frequently in the sacrococcygeal region, is uncertain; whether it is congenital or acquired has been debated considerably. An instance of pilonidal disease, occurring at a previously unreported site, and of definite congenital origin, is reported.
Balloon dilatation of benign oesophageal strictures.
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HIV infectiousness and the AIDS epidemic.
The paper outlines a theory of the AIDS epidemic based on assumptions regarding the changes in infectiousness over the life cycle of the disease. It proposes a short initial period of infectiousness, followed by a long dormant period, which is in turn succeeded by another period of infectiousness, longer than the first period. Each of the two periods of infectiousness can generate an associated epidemic. It is suggested that the Western homosexual epidemic is based on initial stage infectiousness, while the African heterosexual epidemic is mainly the result of end stage infectiousness.
Forearm blood flow measurements using technetium-99m human serum albumin following brachial arteriotomy.
A simple, low cost method for measuring forearm blood flow during reactive hyperemia has been developed. Subjects are seated with hands and forearms over a large field-of-view gamma camera. Blood pressure cuffs inflated above the elbows isolate the blood in the forearms and hands and induce a hyperemic response. The remaining blood pool is labeled with technetium. The rate of increase of activity following release of the cuffs is measured from the gradient of time-activity curves and is calibrated for flow by counting a venous blood sample. The technique has been applied to a group of normal controls and to symptomatic and asymptomatic patients following right brachial arteriotomy. Forearm blood flow in normal subjects was 32.9 +/- 6.4 ml/100 ml/min and for subjects with occlusion of the brachial artery was 6.4 +/- 2.1 ml/100 ml/min. The method is simple, widely available, and reproducible. The good signal to noise ratio allows it to be used in cases of very low flow either as an aid to diagnosis or to measure treatment response.
Familial polyposis coli.
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Oral fluids after major gastrointestinal operations.
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Towards bloodless liver surgery.
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Acute small-bowel mucosal edema following enalapril use.
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Misinformation in the public media relating to craniofacial surgery in New Zealand.
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AIDS incubation period in haemophiliacs.
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Percutaneous dynamic removal of atheroma.
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