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Biomedical subjects

R D Jones

Publications and source records attributed to R D Jones.

At least 163 records · Page 9Linked to original sources
PubMed1986

Epidemiology of brain tumours in man and their relationship with chemical agents.

The 2000 or so deaths that result each year in England and Wales from brain tumours, as defined by ICD 191, represent approximately 0.3-0.4% of all deaths, with a slightly greater incidence in men than in women. Because of the low incidence of mortality from other causes in childhood, brain cancer accounts for 3.5% of all deaths in the 1-14-year age group. Mortality from brain cancer increased considerably between 1931 and 1961 but this is probably explained by changes in disease classification and improvements in diagnostic techniques. Because of the relatively low incidence of brain cancer in man, cohort studies need to be large in order to accrue sufficient cases for meaningful interpretation. Large cohort studies may run the risk of diluting a high-risk group of workers with lesser or non-exposed individuals. These considerations have encouraged the investigation of brain cancer by case-control studies and the interpretation of these must take into account possible sources of bias. At present the evidence for any chemical causation of brain cancer in man is inconclusive.

Acrylonitrile↗
PubMed1986

Mortality of asbestos workers in England and Wales 1971-81.

A national study of British asbestos workers is briefly described and the mortality experience of 31 150 male asbestos workers in England and Wales who had been medically examined at least once as part of that survey is presented. The survey population is divided into workers with occupational exposure to asbestos before the inception of the 1969 Asbestos Regulations and those who worked with asbestos only after 1969. Of the 1128 who had died, 897 had worked before 1969; 34 of the death certificates received for these men mentioned mesothelioma and for another nine asbestosis was reported in the absence of mesothelioma or lung cancer. A statistically significant excess of lung cancer (SMR 136) was found. For the post-1969 workers, one case of asbestosis and one case of mesothelioma were reported, but further investigation of these cases showed probable occupational exposure to asbestos many years before 1969. The time from first exposure for this section of the population is too short to exclude an excess of asbestos related disease. The most noticeable excess of asbestos related disease was seen among the insulation workers who had more than twice (SMR 256) the expected number of deaths from lung cancer, and for whom almost 10% of all death certificates mentioned mesothelioma. No excess of any alimentary tract cancer was found and the population showed a significant deficit of large bowel cancer mortality (SMR 54).

Adolescent↗
PubMed1986

Notifications of industrial chemical cyanosis poisoning in the United Kingdom 1961-80.

In 325 cases of industrial chemical cyanosis notified to Her Majesty's Factory Inspectorate for 1961-80 the incidence of poisonings showed considerable seasonal variation with substantially greater numbers occurring in the summer months. A correlation between the number of poisonings in any one year and the hotness of that summer was also shown. The vast majority of incidents occurred during the manufacture of chemicals or dyestuffs, and two particular workplaces were responsible for 70% of the cases. Poisoning by amino compounds appear to produce early cyanosis whereas poisoning by nitro compounds tended to produce delayed cyanosis. These latter compounds were also more likely to produce anaemia. Methaemoglobin was determined in 45% of cases with results ranging from less than a few per cent to over 50%. Despite concentrations of MetHb over 50%, several workers complained only of headache and their blue appearance.

Adolescent↗
PubMed1986

Absorption study of pentachlorophenol in persons working with wood preservatives.

Plasma and urinary pentachlorophenol (PCP) was measured in 209 workers who had occupational exposure to wood preservatives containing this compound and 101 workers not exposed occupationally to PCP. Workers were examined for chloracne and blood concentrations of bilirubin, gamma-glutamyltransferase (GGT), cholesterol and high-density lipoproteins (HDL) were determined. All the occupationally exposed groups showed evidence of PCP absorption; highest mean concentrations were found in remedial timber-treatment operatives (6.0 mmol/l for plasma and 274 nmol/mmol of creatinine for urine). Timber-yard workers also showed substantial evidence of absorption (mean plasma concentration 4.8 mmol/l). Persons formulating PCP-containing wood preservatives had the lowest concentrations of any exposed group sampled (mean plasma concentration 1.3 mmol/l, mean urinary concentration 39.6 nmol/mmol of creatinine). The occupational groups studied were not standardized for factors known to affect bilirubin, GGT, cholesterol and HDL. The inference that can be drawn from the results of these measurements is therefore limited. There was, however, no evidence of any disadvantageous effect of PCP on health as measured by these parameters. No overt case of chloracne was found.

Acne Vulgaris↗
PubMed1985

Inhibitory effects of secretin on gastrin-stimulated rat colon neoplasms.

A study was done to determine if continuous administration of exogenous secretin would inhibit the trophic effect of elevated endogenous gastrin on colon neoplasms in rats. Colon tumors were induced in 37 Fisher rats by subcutaneous injection of 1,2-symdimethylhydrazine, 20 mg/kg, weekly for 18 weeks. Elevation of endogenous gastrin was achieved by antral exclusion surgery. Control rats received a sham operation. Subcutaneous osmotic minipumps delivered 35.5 U/kg/day of secretin for 7 days before the rats were killed. Rats receiving antral exclusion had significantly elevated serum gastrin levels and increased 3H-thymidine incorporation into tumor DNA compared with sham rats (P less than 0.05). There was a significant decrease in tumor DNA uptake in antral exclusion rats that received secretin as compared with antral exclusion rats without secretin (P less than 0.05). Therefore it appears that gastrin does have a trophic effect on rat colon neoplasms and that secretin does inhibit this effect, in a dose-related manner. The results of this study imply that hormonal manipulation of colon cancer may eventually become a viable therapeutic modality.

Animals↗
PubMed1985

Fecal skatole and indole and breath methane and hydrogen in patients with large bowel polyps or cancer.

The object of this study was to explore the use of fecal skatole and indole and breath methane and hydrogen as metabolic markers of the anaerobic colonic flora in patients with unresected large bowel cancer or polyps. Patients with descending or sigmoid colon cancer were more likely to be breath methane excretors than control subjects, patients with proximal colon cancer, and patients with rectal cancer. Control subjects excreting breath methane excreted less fecal skatole than breath methane excretors in the following groups: patients with adenomatous polyps, all patients with colorectal cancer, patients with proximal colon cancer, patients with descending and sigmoid colon cancer, and patients with rectal cancer. These data suggest that fecal skatole excretion equal to or greater than 100 micrograms/g feces might be useful to discriminate colorectal cancer patients from control subjects. Twenty-nine percent (8 of 28) of the cancer patients had both "high" skatole levels and breath methane excretion compared with only 2% (1 of 41) of the control subjects (P less than 0.01).

Bacteria↗
PubMed1985

Hypergastrinemia and colorectal carcinogenesis in the rat.

Our objective was to determine whether chronic hypergastrinemia enhances chemical induction of rat colorectal cancers. Forty-five rats were randomized to sham operation or antral exclusion. Following a 2-week postoperative recovery period all rats were treated with 1,2-dimethylhydrazine (10 mg/kg) intraperitoneally for 20 weekly doses. Seven weeks later, the rats were killed. Blood was assayed for gastrin by radioimmunoassay. Tumor number, location, size, weight and histology were determined. The 23 rats receiving antral exclusion were hypergastrinemic compared with the 22 sham operated rats. All hypergastrinemic rats developed tumors while only 72.7% of normogastrinemic rats developed tumors. Hypergastrinemia increased the number of tumors/rat, total tumor weight/rat and total tumor volume/rat.

Animals↗
PubMed1985

Mesothelioma of the peritoneum during 1967-82 in England and Wales.

The time-trend and geographical distribution of mesothelioma of the peritoneum during the years 1967-82 in England and Wales have been studied from the Mesothelioma Register held by the Medical Division of the Health and Safety Executive. Over the 16-year period the annual number of cases registered rose from about 15-20 to about 30-50. Although the number occurring in men was double that in women, the trend was similar for both sexes. There is likely to be some further increase before any improvement due to the recent diminished usage of asbestos is seen. Local Authority areas with raised rates have been identified, and the geographical pattern is similar to that of the distribution of the asbestos-using industry in the past. In both sexes there are high registration rates on the east side of London but, in contrast to mesothelioma of the pleura, a concentration of cases among men in the major ports where shipbuilding and ship repairing were carried out is not so apparent.

Adult↗
PubMed1985

Gassings due to methylene chloride, xylene, toluene, and styrene reported to Her Majesty's Factory Inspectorate 1961-80.

For the period 1961-80, 118 cases of industrial gassings caused by the solvents methylene chloride, xylene, toluene, and styrene were reported to Her Majesty's Factory Inspectorate. The data have been collated and analysed according to the predetermined criteria of age, sex, mode and circumstances of use, clinical effect, and outcome. The means of collection of the data and their objectivity is discussed. The study shows the narcotic effect of these solvents and underlines the dangers of their use in confined spaces. Symptoms were most commonly attributable to the nervous and respiratory systems. The problem of addiction and the vulnerability of the younger worker is also discussed.

Adolescent↗
PubMed1985

Perioperative management of neonatal aortic isthmic coarctation.

Aortic isthmic coarctation is a common cardiovascular cause of neonatal mortality. This study reviews retrospectively sixty-one consecutive neonates operated on for this condition at the Royal Children's Hospital, Melbourne, in the years 1978-1983 inclusive. In this series, the overall mortality has fallen from 50% and 67% in 1978 and 1979 respectively, to 11% in 1983. In the last three years of this review, there have been no early hospital deaths and the late deaths relate to associated congenital anomalies. The decrease in mortality is ascribed to methods of perioperative support, non-invasive cardiac investigation, and surgical repair with subclavian aortoplasty. Prior to surgery, all infants are paralysed, mechanically ventilated and infused with prostaglandin E1 to reopen the ductus arteriosus, and dopamine to support the failing myocardium. The physical status of all infants improved with these maneuvres. This paper reviews the pathophysiology of neonatal aortic coarctation, the current modes of management, results and complications.

Alprostadil↗
PubMed1985

Mortality of styrene production, polymerization and processing workers at a site in northwest England.

The mortality of 622 men who worked for at least one year in the production, polymerization, and processing of styrene at a chemical site in the United Kingdom during the period 1945-1974 was surveyed up to the end of 1978; 3 072 male manual workers at the same site but unexposed to styrene were also studied. A statistically significant excess of lymphoma deaths was found in the exposed population, and two of the three deaths observed occurred in men less than 40 years of age. The small number of deaths and the lack of any evidence for an association with duration or level of exposure to styrene are reasons for interpreting this result cautiously. However, the otherwise normal pattern of mortality in the exposed population and the absence of any excess of lymphomas in the reference group lend some support to suggestions that exposure to styrene may be associated with lymphomas in man. An analysis of cancer registrations for the exposed population revealed no further cases of lymphoma but identified one case of lymphatic leukemia. An excess of laryngeal cancer registrations was found. As this effect has not been previously postulated and because of the small number of registrations, too much weight should not be attached to this one observation.

Adult↗
PubMed1983

Comparison of effects of pentagastrin and gastrin on rat colon mucosa.

The trophic effect of chronic endogenous hypergastrinemia is compared with that of short term injected pentagastrin on colon mucosa of rats. Hypergastrinemia was achieved by antral exclusion. Pentagastrin (2 mg/kg) was administered to a group of sham operated rats every 12 hr for 48 hr prior to sacrifice. Normogastrinemic antrectomized and sham operated animals were studied as controls. Tissue content and synthesis of DNA, RNA, and protein were all markedly increased by both endogenous gastrin and exogenous pentagastrin. The stimulation by gastrin was significantly stronger than that of pentagastrin at the chosen schedule of administration.

Animals↗