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Biomedical subjects

M E Lambert

Publications and source records attributed to M E Lambert.

28 records · Page 2Linked to original sources
PubMed1986

Development of a computerized reference retrieval system: a behavior therapy training tool.

The vastness of the behavior therapy literature base often poses problems for beginning therapists who need greater familiarity with assessment and intervention literature. Hence a computerized reference retrieval system was developed for trainees to access behavior therapy references efficiently. The system contains over 1600 references from 158 problem categories and is economically competitive with commercial systems. Similar systems can be established using currently available microcomputer technology. The present system is primarily used by doctoral and masters students to assist in case conceptualizations and decision making during practicum courses.

Behavior Therapy↗
PubMed1986

Carcinogen induced asynchronous replication of polyoma DNA is mediated by a trans-acting factor.

We have demonstrated that carcinogen damage to DNA induces the production of cellular factors that act in trans to enhance the asynchronous replication of polyoma viral DNA. Exposure of a polyoma virus-transformed rat cell line to benzo[a]pyrene-7,8-diol-9,10-oxide (BPDE), the ultimate carcinogenic metabolite of benzo[a]pyrene, led to the accumulation of heterogeneously sized free viral DNA molecules which contain polyoma origin sequences as well as cellular sequences that flank the integrated viral DNA. When the sequence gpt was linked to the polyoma early region and transfected into rat cells, it underwent asynchronous replication in response either to direct treatment of the transfected cells with BPDE, or to fusion of untreated transfected cells with normal cells previously exposed to BPDE. Transient arrest of the cell cycle by hydroxyurea, isoleucine deprivation or methotrexate caused a slight enhancement of viral DNA replication when compared with BPDE. Both aphidicolin, an inhibitor of DNA polymerase alpha, and 3-aminobenzamide, an inhibitor of poly[ADP]ribosyl transferase, caused marked inhibition of BPDE-induced viral DNA synthesis. The induction of a trans-acting factor in response to damage of cellular DNA may be relevant to synergistic interactions between environmental chemicals and DNA viruses in cell transformation and to the general phenomenon of gene amplification.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1983

Benzo[a]pyrene induction of extrachromosomal viral DNA synthesis in rat cells transformed by polyoma virus.

The effect of the carcinogen benzo[a]pyrene (BP) on the production of specific extrachromosomal DNAs has been studied in transformed rat cells containing integrated polyoma virus DNA. Exposure of cells previously transformed by the polyoma virus mutant ts-a, which codes for a temperature sensitive T antigen, to a non-toxic dose of BP (0.25 micrograms/ml) enhanced the production of free polyoma DNA at the population level. This occurred at 33 degrees C (the permissive temperature) but not at 39 degrees C, indicating that the BP effect was dependent on the function of the T antigen of polyoma virus. In the same cell system, BP did not induce the production of extrachromosomal copies of two endogenous rat retrovirus genomes, the 30S RNA virus and rat leukemia virus. Thus, the effects on integrated polyoma DNA are quite specific and do not reflect a generalized increase in asynchronous DNA replication and excision. Further studies utilizing a carcinogenic metabolite of BP, benzo[a]pyrene trans-7,8-dihydrodiol-9,10-epoxide (anti) (BPDE), on a rat cell line transformed by wild type (WT) polyoma virus demonstrate that the enhancement of polyoma DNA synthesis persists for at least 5 days after a single exposure to BPDE, despite the rapid decay of this compound. In addition, enhanced synthesis of polyoma DNA can be induced by fusion of normal rat fibroblasts previously exposed to BPDE with polyoma transformed rat fibroblasts not exposed to BPDE. It appears, therefore, that the effects we have observed are not due solely to direct carcinogen damage at the level of the integrated polyoma virus DNA, but may instead involve the induction of cellular factor(s) that act indirectly to enhance asynchronous replication of polyoma DNA.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1979

Campylobacter colitis.

Eleven consecutive patients with diarrhoea from whose stools campylobacter were isolated were investigated by sigmoidoscopy and rectal biopsy. Eight had definite proctitis, and in seven biopsy specimens were abnormal with histological changes ranging from non-specific colitis to gross colitis with goblet-cell depletion and crypt-abscess formation. Nine of the patients passed blood in their stools, and in all but one abdominal pain was a feature of the illness. Severe campylobacter colitis may be clinically, sigmoidoscopically, and histologically difficult to differentiate from ulcerative colitis and is a differential diagnosis in acute colitis.

Adolescent↗
PubMed1978

Value of bile-acid binding agents in post-vagotomy diarrhoea.

Cholecystectomy increases the incidence of post-vagotomy diarrhoea. The effect of agents which either bind bile acids or prevent their action on the colonic mucosa has been studied in 31 patients with post-vagotomy diarrhoea--15 had had vagotomy and pyloroplasty alone and 16 vagotomy and pyloroplasty and cholecystectomy. Cholestyramine was particularly useful after the combined operation. Aluminium hydroxide in large doses has a similar mechanism of action to cholestyramine and is cheaper and more palatable, but propranolol was of no value. This study suggests that the excretion and chemical composition of bile and the handling of bile acids by the small intestine is of fundamental importance in the pathogenesis of post-vagotomy diarrhoea.

Aluminum Hydroxide↗
PubMed1978

Should cholecystectomy be combined with vagotomy and pyloroplasty?

Duodenal ulcers and gallstones, two of the commonest surgical conditions, affect respectively 10% of men and up to 20% of the population. Although many detailed studies of the treatment of these conditions have been conducted, there is no report of the results of surgery when the conditions coexist. 60 patients who had undergone vagotomy, pyloroplasty, and cholecystectomy were compared with age and sex matched controls who had undergone vagotomy and pyloroplasty alone or cholecystectomy alone. In the early postoperative period after the combined procedure there was a very high incidence of post-vagotomy diarrhoea (48.3%, P equal to 0.00013) and bile-reflux gastritis. The findings implicate bile-acids--their excretion and handling by the small intestine--in the aetiology of post-vagotomy diarrhoea. Where the conditions coexist truncal vagotomy and pyloroplasty should be avoided in the treatment of the duodenal ulcer because of the risk of post-vagotomy diarrhoea and bile-reflux gastritis.

Adult↗
PubMedDate not supplied

Experience with the Portacath.

Fifty Portacaths have been inserted in patients undergoing prolonged outpatient chemotherapy, most for haematological disease. Twenty-one are still working at a median duration of 12 months (range 1-27) and a further 15 were functioning normally at the time of the patients death (median survival 6 months). Four functioning Portacaths have been removed, three suspected of causing septicaemia and one believed erroneously to have occluded. Ten have ceased to function and nine of these have been removed. The causes of these failures are nearly all avoidable and are discussed in detail; many occurred early in our experience. With careful attention to detail and with management by trained and interested staff, the Portacath is a safe and reliable device for intermittent vascular access.

Antineoplastic Agents↗
PubMedDate not supplied

Serum carnitine levels in normal individuals.

Serum carnitine levels have been measured in 178 samples from 75 normal volunteers. We report a wide range of values (10-70 mumol/liter and 8-74 mumol/liter for free and acetylated carnitine, respectively) and a distinct difference between the ranges for males and females (p less than 0.001). There is also substantial, seemingly random fluctuation in any one individual's levels, when measured serially over several weeks.

Carnitine↗
PubMedDate not supplied

Ruptured abdominal aortic aneurysms.

A series of 180 consecutive patients with ruptured aortic aneurysms has been studied to determine the causes of death. 18% died before operation could be carried out, 8% proved inoperable and a further 10.5% died before operation could be completed. Overall mortality was 75%. By multivariate analysis, the most significant preoperative features influencing survival were a systolic BP less than 80 mmHg on admission and a history of hypertension, angina or myocardial infarct. The mortality increased with increasing age. Administration of fresh frozen plasma preoperatively significantly increased survival. However, we could not identify a single group of patients for whom the outcome was inevitably fatal.

Adult↗