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Biomedical subjects

R M Clark

Publications and source records attributed to R M Clark.

At least 109 records · Page 6Linked to original sources
PubMed1982

Results of treating Hodgkin's disease without a policy of laparotomy staging.

Results of the treatment of 780 primary patients with Hodgkin's disease at the Princess Margaret Hospital (PMH) between 1968 and 1977 are analyzed. Treatment decisions were based on the evaluation of the extent of disease by clinical methods. A marked improvement in relapse-free survival and overall survival was observed for 1973-1977 as compared to 1968-1972. This improvement did not result from differences in the distribution of important prognostic attributes (clinical stage, pathology, and age) between the two periods, and there was no improvement in our ability to rescue relapsed patients. Improved relapse-free and overall survival during the second period was observed for all stages in patients less than 50 years of age, but not in the older group. The improved survival of patients treated between 1973 and 1977 is attributed to more effective initial therapy, which reduced the fraction of patients who relapsed. These observations provide indirect evidence that relapse has a negative effect on prognosis, and that the initial treatment of patients with Hodgkin's disease should be designed to reduce the risk of relapse to a minimum without causing an unacceptable increase in late complications. The observed/expected incidence of acute leukemia and non-Hodgkin's lymphoma in the PMH series was increased to 41.9 and 13.9 respectively. The question of whether a policy of doing routine staging laparotomies improves the results of treatment of patients with Hodgkin's disease is considered only in general terms by comparing the total PMH series with the total Stanford Medical Center series of patients treated between 1968 and 1977. Relapse-free survival at 10 years is 48.9% and 66.8% respectively, at the two institutions, while overall survival at 10 years is identified.

Adult↗
PubMed1982

Squamous cell carcinoma of the oral cavity.

This paper describes the treatment of squamous cell carcinomas of the oral cavity in patients referred to the multidisciplinary clinics at the Princess Margaret Hospital. The majority of squamous cell carcinomas at this site involve the tongue and floor of mouth. One third have clinically abnormal cervical nodes at the time of presentation, and a further third are believed to have subclinical node involvement. Small superficial carcinomas are usually treated by simple excision. Approximately one quarter of the patients have tumors so extensive that only palliative treatment is possible. Most patients are treated by initial irradiation and surgery is reserved for those with residual or recurrent carcinoma. The basis for this policy and the results achieved in the treatment of oral cavity tumors are discussed. The overall adjusted five year survival for all patients is approximately 50%.

Carcinoma, Squamous Cell↗
PubMed1981

Symposium on the management of early breast cancer (stages I and II). Part II: Clinical experience with treatment methods. 3. Conventional surgery and radiotherapy.

Conservative surgery (local tumour excision) for early breast cancer gives long-term survival rates comparable to those after radical treatment. Irradiation postoperatively reduces recurrence in the breast by at least 50%. The value of irradiating the internal mammary nodes in patients whose lymphoscintogram confirms the presence of cancer in these nodes remains to be determined. Radical surgery does not improve the survival rate and excessively radical radiotherapy may induce morbidity equal to the operation it is intended to replace. The demise of radical surgery is predicted and a plea made for the use of adjuvant chemotherapy or hormonal therapy, or both, for high-risk patients following conservative treatment.

Axilla↗
PubMed1980

Composition of the lipids in human milk: a review.

Recent publications on the composition of human milk are reviewed. The importance of proper sampling is discussed. Fat contents of 2.6-4.5% and cholesterol amounts of 200-650 mg/100 g fat were reported. The phytosterols in milk were increased by the consumption of these sterols. Phytosterols could contribute to the "total cholesterol" in milk if analyses are done colorimetrically. The fatty acid composition is remarkably uniform unless bizarre diets are consumed; the amounts of linoleic acid vary the most. Phospholipids contained more long chain polyunsaturated fatty acids than triacylglycerols.

Animals↗
PubMed1980

Internal mammary lymphoscintigraphy in the conservative surgical management of breast carcinoma.

Radiocolloid internal mammary lymphoscintigrams were carried out in 249 women who had undergone partial mastectomy. Only 39 patients, or 15%, had axillary sampling; of these, 19 were positive. At last follow-up, a minimum of two years from the date of study, the overall recurrence rate was 67% for patients with an abnormal lymphoscintigram and 34% for those with a normal lymphoscintigram. Actuarial survival rates projected to five years indicate a statistically significant difference in the prognostic implications of the normal and abnormal internal mammary lymphoscintigram, with 83 and 59% survival rates, respectively.

Adult↗
PubMed1980

Extracellular amino acid effects on milk protein synthesis and intracellular amino acid pools with bovine mammary cells in culture.

Increases in free intracellular amino acids are associated with increased protein synthesis. Responses in synthesis of beta-casein and beta-lactoglobulin and of intracellular amino acid pools to graded concentrations of amino acids in the medium were observed. Mammary tissue from two Holstein cows was dispersed and cultured for 18 h with Eagle's minimal essential medium containing 1, 3, 5, or 7 times the basic concentration of amino acids. Synthesis of beta-casein and beta-lactoglobulin increased with concentration of amino acids in the medium. Intracellular pools of amino acids not provided by the medium (serine, proline, alanine, glycine, glutamic acid, ornithine) generally decreased with increased concentrations of amino acids in the medium, the exception being ornithine which increased with extracellular amino acids. Lysine, histidine, tyrosine, leucine, valine, phenylalanine, isoleucine, arginine, and threonine intracellular pools increased with increased amino acids in medium. Intracellular cystine responded with a small linear increase to increased amino acids in the medium, while intracellular tryptophan and methionine did not respond, indicating potential limitations from these amino acids.

Amino Acids↗
PubMed1980

Prognostic value of skin testing with dinitrochlorobenzene in patients with head and neck cancer.

Of 107 patients with cancer of the head and neck region in whom sensitization with dinitrochlorobenzene (DNCB) was attempted at the time the patient first presented, 57 became positive while 50 remained negative. These two groups were similar with respect to age, sex, involved sites and extent of tumour at presentation, but the mortality in the DNCB-negative group (38%) was twice as high as that in the DNCB-positive group (17.5%). Since both groups were treated in a similar fashion and have been followed-up for equal periods of time, the difference in mortality suggests that DNCB skin testing is of prognostic value in patients with cancer in the head and neck region.

Adult↗
PubMed1979

Ovarian irradiation and prednisone therapy following surgery and radiotherapy for carcinoma of the breast.

Following mastectomy, patients with operable breast cancer underwent postoperative irradiation of the chest wall and regional lymph nodes. They were then assigned at random to receive no further therapy, ovarian irradiation (2000 rads in 5 days) or ovarian irradiation in the same dosage plus prednisone, 7.5 mg daily. A total of 705 patients received the randomly assigned treatment and were followed for up to 10 years. In premenopausal patients who received ovarian irradiation the recurrence of breast cancer was delayed and survival prolonged, but not significantly. In premenopausal women aged 45 years or more ovarian irradiation plus prednisone therapy significantly delayed the recurrence of breast cancer (P = 0.02) and prolonged survival (P = 0.02); the survival expectancy of these patients was similar to that of the general population of the same age from the third year after the cancer operation. No value was demonstrated for ovarian irradiation with or without prednisone therapy in postmenopausal patients.

Adult↗
PubMed1979

Cholesteryl ester and triacylglycerol fatty acids in type V hyperlipidemia.

The fatty acid compositions of plasma cholesteryl esters (CF) and triacylglycerols (TG) from seven healthy individuals and five patients with type V hyperlipoproteinemia were determined. Very low density (VLDL), low density (LDL) and high density lipoproteins (HDL) wer isolated. The lipids were extracted from the lipoproteins and the triacylglycerols and cholesteryl esters separated for analysis. The fatty acid compositions of triacylglycerols from healthy and type V individuals were very similar. The cholesteryl esters from type V patients had increased contents of palmitic and decreased amounts of linoleic and arachidonic acids as compared to the normal individuals. The fatty acid composition of the cholesteryl esters from high density lipoproteins had the greatest deviation. The fatty acid compositions of the triacylglycerols from the two groups were similar. However, the triacylglycerols in all lipoprotein fractions contained more palmitic and oleic and less linoleic and arachidonic acids than the cholesteryl esters.

Adult↗
PubMed1978

Limiting amino acids for milk protein synthesis by bovine mammary cells in culture.

Experiments are presented to determine the effect of labeled precursor amino acid on synthesis of beta-lactoglobulin and beta-casein and to identify the most limiting amino acids in Eagle's minimal essential medium for synthesis of milk protein. Protein synthesis was measured by incorporation of carbon-14 labeled amino acids into milk protein from bovine mammary cell culture. Mammary tissue from 13 Holsteins (12.7 kg milk/day) was dispersed and cultured for 18 h. In Experiment 1, three replications (cows) with three amino acid mixtures, utilizing labeled lysine or leucine as the marker amino acid, showed that labeled lysine overestimated the effect of medium lysine, and labeled leucine overstimated the effect of leucine on beta-lactoglobulin and beta-casein synthesis. Subsequently Experiment 2 utilized 10 replications (cows) to determine the effect of a three-fold increase of each of 13 amino acids in Eagle's medium. Increased threonine or methionine improved beta-lactoglobulin synthesis and cystine increased beta-casein. Second and third best response in beta-casein were from addition of methionine and threonine. Combined analysis from 10 cows and two protein responses by multivariate procedures identified, in order of decreasing magnitude, cystine, threonine, and methionine as limiting amino acids in the dispersed cell culture.

Amino Acids↗