PubMed Health⌕ Search

Biomedical subjects

F J Thomas

Publications and source records attributed to F J Thomas.

At least 37 records · Page 2Linked to original sources
PubMed1987

Eight years experience with neutron radiotherapy in the treatment of stages C and D prostate cancer: updated results of the RTOG 7704 randomized clinical trial.

The records of 91 patients enrolled between June 1977 and April 1983 in the Radiation Therapy Oncology Group (RTOG) randomized study investigating fast neutron radiation therapy in the treatment of locally advanced prostate cancer were reviewed. Patients with stages C and D1 adenocarcinoma were randomized to receive either combined fast neutron and photon irradiation (mixed-beam) or conventional photon irradiation alone. Survival (actuarial) at eight years for the mixed-beam cohort was 63% vs 13% for the patients receiving photons alone (P = .01). Corresponding "determinental" survival rates, adjusted by exclusion of intercurrent deaths, were 82% and 54%, respectively (P = .02). Freedom from locally recurrent prostate cancer was 77% for mixed-beam patients and 31% for patients receiving photons alone (P less than .01). Analyses of outcomes accounting for all major prognostic determinants confirm the greater efficacy of mixed beam treatment with P less than .05 for survival, determinental survival, and local control.

Adenocarcinoma↗
PubMed1987

Response of a non-Hodgkin lymphoma to 60Co therapy monitored by 31P MRS in situ.

High quality 31P MR spectra (signal to noise ratio (S/N) approximately 18, 15 min acquisition for each spectrum) were consistently obtained with surface coils over a period of 6-week RT. Both transient and steady state alterations in metabolites in response to RT were found in this case. The transient changes occurred during the first 3 hr immediately after the 3rd fractionated RT, these changes include the transient elevation of the PCr resonance, a decrease in PDE and an increase in intracellular pH. The monitoring showed that the metabolites approached steady state approximately 2 hr after the fractionated radiation intervention, suggesting that in vivo MRS can be useful for studying the dynamics of tumor response to RT such as repair of potential lethal damage, growth delay, and reoxygenation etc. The steady-state MR spectra showed the net response to each intervention and can clinically be useful for predicting and measuring the result of the fractionated RT. In this case study, the PDE peak which contains the phospholipid metabolites GPC and GPE, is the most sensitive resonance in response to RT. After the 3rd RT, prior to tumor size reduction, the PDE to ATP ratio decreased 33% and intracellular pH increased to 7.34 +/- 0.05 from 7.27 +/- 0.05. In the subsequent RT interventions, both the tumor size and PDE/ATP ratio continually decreased whereas the pH values remained alkaline and fluctuated around 7.34 to 7.65. The data suggest that the phospholipid metabolite PDE may signal important alterations in membrane metabolism that eventually lead to cell death.

Cobalt Radioisotopes↗
PubMed1987

Cimetidine decreases aspirin-induced gastric mucosal damage in humans.

Aspirin induces gastric mucosal damage in animals and humans. The purpose of this study was to examine whether cimetidine protects the human gastric mucosa from acute aspirin-induced damage. Eight healthy subjects were studied on 4 separate days. Cimetidine, 400 mg, or placebo was given orally 1 hour before initial endoscopy. The stomach was isolated and atropine given to suppress basal acid secretion. Each study consisted of four 15 min periods during which an acidic test solution was instilled into the stomach. During the second period only, either aspirin (1300 mg, 36 mmol) or control for aspirin (36 mmol HCl) was added to the test solution. Ion fluxes and gastric mucosal potential difference were measured, and endoscopy performed following each test. After placebo, aspirin significantly altered hydrogen ion flux and potential difference versus basal and control. Cimetidine decreased the damaging effect of aspirin. Endoscopic scores increased after aspirin plus placebo, whereas they remained unchanged after aspirin plus cimetidine. Therefore, cimetidine decreased aspirin-induced gastric mucosal damage in humans. As gastric acidity was identical during all studies, the effect of cimetidine was independent of gastric acid secretion.

Adult↗
PubMed1986

Enprostil, a synthetic prostaglandin E2 analogue, inhibits meal-stimulated gastric acid secretion and gastrin release in patients with duodenal ulcer.

The effect of enprostil, a synthetic dehydro-prostaglandin E2, on meal-stimulated gastric acid secretion and gastrin release was studied in six patients with inactive duodenal ulcer disease. Each subject underwent seven tests in random order on separate days: placebo intragastrically and intraduodenally; enprostil 35 and 70 micrograms both intragastrically and intraduodenally; and ranitidine 150 mg intragastrically. After measuring basal gastric acid secretion and gastrin release, a liquid meal (500 ml, pH 5.5, 40 g protein, 30 g fat, 30 g carbohydrate, 550 Kcal, 768 mOsm) was given. Gastric acid secretion and gastrin release were measured over the next four hours. A second identical meal was instilled and both parameters were measured for an additional four hours. Thirty-five and 70 micrograms of enprostil administered intragastrically reduced total eight-hour gastric acid secretion by 58 percent and 82 percent, respectively (p less than 0.05). The 35 and 70 microgram doses administered intraduodenally decreased gastric acid secretion by 67 percent and 91 percent, respectively (p less than 0.05 compared with placebo). Ranitidine suppressed gastric acid secretion by 95 percent, which was similar to the suppression achieved with the 70 microgram dose of enprostil. The total meal-stimulated integrated gastrin response was significantly suppressed by both intragastric doses of enprostil and by the 70 microgram dose given intraduodenally (p less than 0.05). Compared with placebo, the 35 microgram intragastric and intraduodenal doses decreased the integrated gastrin response by 73 percent and 72 percent, respectively. The 70 microgram intragastric and intraduodenal doses of enprostil reduced the integrated gastrin response by 90 percent and 125 percent, respectively. Ranitidine did not alter the integrated gastrin response. It is concluded that enprostil significantly inhibited both meal-stimulated gastric acid secretion and gastrin release. The response to enprostil occurred in a dose-dependent manner and was similar regardless of the route of administration.

Duodenal Ulcer↗
PubMed1986

Evaluation of a neutron boost in head and neck cancer. Results of the randomized RTOG trial 78-08.

Patients with untreated squamous cell cancer of the head and neck region were randomized to receive either a boost of 25-30 Gy using photon-beam irradiation (photons) or an equivalent boost using neutron-beam irradiation (neutrons). All patients received an initial 45-50 Gy of wide-field photon irradiation. A total of 57 patients was evaluable on the neutron arm and 58 were evaluable on the photon arm. The proportion of patients with complete responses was 60 and 64% on the neutron and photon arms, respectively. The locally disease-free proportion at 2 years was estimated to be 20 and 31%, and the 2-year survival was estimated to be 32 and 41%, respectively. These differences are not statistically significant. There was a higher rate of severe complications on the neutron arm, 16 versus 7%. Thus, there was no evidence that a neutron boost produces better initial tumor clearance, local tumor control, or survival than a photon boost, and it may produce more complications.

Carcinoma, Squamous Cell↗
PubMed1986

Fast neutron and mixed beam radiotherapy for inoperable non-small cell carcinoma of the lung. Results of an RTOG randomized study.

From July 1979 through March 1984 the Radiation Therapy Oncology Group conducted a randomized study comparing fast neutron radiotherapy versus mixed beam (neutron/photon) radiotherapy versus conventional radiotherapy for patients with non-small cell carcinoma of the lung. Patients were either medically or technically inoperable. One hundred two evaluable patients were placed on the study. The radiation doses were approximately 60 Gy-equivalent on each arm. Patients were stratified according to size of primary, histology, Karnofsky performance status, and age distribution. Overall local response rates as measured by serial radiographs were the same on the three arms, and an actuarial analysis showed no significant differences in either median or long-term survival. However, for the subgroup of patients exhibiting a complete or partial tumor response at 6 months there was a suggestion of improved 3-year survival on the two experimental arms (mixed beam, 37%; neutrons, 25%; photons, 12%). The p value for the difference between the mixed beam and photon curves is 0.14 (two-sided test). The incidence of major complications was higher on the neutron and mixed beam arms. These complications included four cases of myelitis which are analyzed in detail. The results are placed in the context of other published work on the use of neutrons in the treatment of lung cancer.

Fast Neutrons↗
PubMed1986

Duodenal mucosal bicarbonate secretion in humans: a brief review.

The human proximal duodenum serves as the crucible for the neutralization of gastric acid. Methods have been developed and validated that permit isolation of 4-cm segments of either the proximal or distal duodenum. These isolated segments were free of contamination from gastric, pancreatic, and biliary secretions. At rest the healthy human proximal duodenum produced approximately 175 mumol cm-h: or, assuming that the duodenal bulb is approximately 4 cm in length, 700 mumol h. The distal duodenum (the third part) produced significantly less bicarbonate, approximately 25 mumol/cm-h. HCl produced a prompt and sustained increase in bicarbonate output from both duodenal segments. Bicarbonate output was less in the distal duodenum, indicating a proximal-to-distal gradient. Synthetic prostaglandin E1 caused a dose-related increase in output. Substitution of the NaCl perfusate with Na2SO4 produced a brief decrease, suggesting a chloride bicarbonate exchange mechanism. Vasoactive intestinal polypeptide significantly increased proximal duodenal bicarbonate output. Bicarbonate production by the duodenal mucosa is probably an important defensive factor in maintaining mucosal integrity.

Alprostadil↗
PubMed1985

Fast neutron radiotherapy for locally advanced prostate cancer: results of an RTOG randomized study.

Between June 1977 and April 1983, the Radiation Therapy Oncology Group (RTOG) sponsored a Phase III randomized study investigating fast neutron radiation therapy in the treatment of patients with locally advanced (Stage C and D1) adenocarcinoma of the prostate gland. Patients were randomized to receive either conventional photon radiation therapy or fast neutron irradiation used in a mixed-beam treatment schedule (neutron/photon). A total of 91 analyzable patients were entered in the study; 78 of them were treated without major protocol deviations. The two treatment groups were balanced in regard to all major prognostic variables. Actuarial curves for "overall" survival, "determinantal" survival and local/regional control are presented both for the entire group of 91 patients and the 78 patients treated within protocol guidelines. The overall local/regional tumor recurrence rate is 7% for the mixed-beam treated group of patients and is 22% for the photon (X ray) treated group of patients. The difference is statistically significant at the p = 0.05 level. For the entire group of 91 evaluable patients, the 5-year "overall" survival rate is 62% for the mixed-beam-treated group and 35% for the photon-treated group. This difference is also statistically significant (p less than 0.05). However, this statistical significance is lost when the smaller number of patients treated strictly within protocol guidelines is considered. The significance is regained (p less than 0.02) when one looks at "determinantal" survival, which uses active cancer at time of death as the failure endpoint. This study demonstrates that a regional treatment modality, in this case mixed-beam irradiation, can influence both local/regional tumor control and survival in patients with locally-advanced adenocarcinoma of the prostate gland.

Adenocarcinoma↗
PubMed1981

Sites of steroid production in the polycystic ovary.

Tissue culture of slices of polycystic ovaries shows that androstenedione and oestradiol are mostly produced by the cortical, cyst-containing portions, with little steroid production in vitro by medullary stromal tissues.

Adolescent↗
PubMed1980

Heart and kidney transplantation using total lymphoid irradiation and donor bone marrow in mongrel dogs.

Heart and kideny allografts showed markedly prolonged survival in unrelated mongrel dogs following total lymphoid irradiation (TLI) and donor bone marrow without any other immunosuppression. In every animal the heart survived longer than the kidney; genetic disparity was ruled out, since the heart and kidney from the same donor were placed into one recipient. Placing the kidney allograft in the abdomen with the bone marrow given intraperitoneally doubled kidney survival over placement in the neck, but heart survival was equally prolonged in the abdomen or neck. Splenectomy before TLI or after TLI, but just before transplantation, almost completely eliminated the prolonged survival of both heart and kidney allografts. Thus there is suggestive evidence from the work of Slavin and his colleagues and from our study that TLI plus bone marrow from the donor may be valuable for transplantation in man, particularly heart transplantation.

Animals↗
PubMed1972

Radioimmunoassay of human growth hormone: technique and application to plasma, cerebrospinal fluid, and pituitary extracts.

A radioimmunoassay for human growth hormone using activated charcoal is described and its precision, accuracy, and sensitivity are defined. Results are presented for growth hormone measurements in plasma obtained during hypoglycaemia induced with insulin in patients of short stature and during glucose tolerance tests in patients with acromegaly. The method was used to measure growth hormone concentrations in cerebrospinal fluid and in extracts of pituitary tumours. No growth hormone was detected in the cerebrospinal fluid of patients without acromegaly. In patients with acromegaly, the concentration of growth hormone in cerebrospinal fluid was measurable and was considerably elevated in one patient with extrasellar extension of a pituitary tumour. Extracts of chromophobe pituitary tumours contained very small concentrations of growth hormone. In extracts of pituitary tumours removed from acromegalic patients, concentrations fell either below or within the normal range.

Acromegaly↗