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Biomedical subjects

G Clark

Publications and source records attributed to G Clark.

At least 127 records · Page 7Linked to original sources
PubMed1982

Androgen priming and cytotoxic chemotherapy in advanced prostatic cancer.

Hormone manipulation has been standard therapy for metastatic adenocarcinoma of the prostate for many years. Recently cytotoxic drugs have been studied, but their effectiveness has been limited, indicating the need for new therapeutic approaches. Based upon the hypothesis that cytotoxic drugs are most effective against actively proliferating cells, we have designed a clinical pilot study employing cyclical androgen priming to transiently stimulate tumor cells followed by cytotoxic chemotherapy with cyclophosphamide and methotrexate. There were nine responders (43%) out of 21 patients entered in the study, with a median duration of response that has not been reached at 9+ months. Survival was significantly better in responders than in non-responding patients. These results are similar to those of other studies in which chemotherapy was used alone. Chemotherapy toxicity with this schedule was mild. However, the androgen priming frequently resulted in increased bone pain, and there was one episode of spinal cord compression, suggesting that tumor stimulation was achieved. These results demonstrate the need for additional basic studies of the effects of testosterone on tumor cell kinetics before further clinical trials of this approach are initiated.

Aged↗
PubMed1982

Peripartum pseudomalignant myositis ossificans of the finger.

Two cases of pseudomalignant peripartum myositis ossificans of the finger are reported. The benign diagnosis is confirmed by the histologically characteristic zone phenomenon, consisting of a transition from an inner zone of proliferating spindle cells to a middle zone of well-oriented osteoid and finally to an outer zone of mature bone. In Case No. 1, because of the question of malignancy, a ray amputation was performed. In Case No. 2, the patient was observed during the peripartum period to show diminution in the size of the tumor. The lesion was eventually treated by local excision.

Adult↗
PubMed1982

Temazepam as premedication in elderly patients.

One hundred and forty-five men were randomly allocated on a double-blind basis to receive either temazepam 20 mg, diazepam 10 mg or placebo as premedication. Temazepam produced more sedation than either diazepam or placebo. Postoperative recovery was assessed by a simple visuo-motor co-ordination test and was best in the placebo group. Two hours into recovery, temazepam patients could almost match their baseline performance whereas the performance of the diazepam patients was still significantly worse than pre-operatively. Temazepam is suggested as a suitable premedicant for elderly patients undergoing minor surgery.

Aged↗
PubMed1981

Utilization of a human tumor cloning system to monitor for marrow involvement with small cell carcinoma of the lung.

We have compared the sensitivities of two methodologies for determining bone marrow involvement by small cell lung cancer. These methodologies included histological examination of marrow aspirations and biopsies versus growth of tumor colonies in soft agar. There were four instances in which histological study of the marrow aspirate (and biopsy) revealed metastatic small cell lung cancer. All four of the specimens formed colonies in soft agar. Thirty-four of 37 histologically negative aspirations and biopsies) showed no growth in the soft agar system. However, three histologically negative specimens formed colonies in soft agar. The cells growing in these colonies were documented to be small cell lung cancer by histology and growth in nude mice. We conclude that small cell lung cancer metastatic to bone marrow will form colonies in soft agar. Additional study is needed to determine if the soft agar system is indeed more sensitive than routine histology in detecting small cell lung cancer metastatic to bone marrow.

Agar↗
PubMed1981

Phase I clinical investigation of 9,10-anthracenedicarboxaldehyde bis[(4,5-dihydro-1 H-imidazol-2-yl)hydrazone] dihydrochloride (CL216,942).

9,10-Anthracenedicarboxaldehyde bis[(4,5-dihydro-1 H-imidazol-2-yl)hydrazone] dihydrochloride (CL216,942) is a new anthracene bishydrazone derivative that was evaluated in a Phase I clinical trial. The schedule of administration consisted of a single i.v. injection repeated at 4-week intervals. Twenty-eight patients received a total of 61 courses of the drug in a dose range of 20 to 280 mg/sq m. Leukopenia was the dose-limiting toxicity. It was of short duration and reversible. A drug-induced hypotension was noted at higher doses in three patients. The hypotension was not dose limiting, it was reversible, and it could largely be avoided by prolonging the drug infusion time to 1 hr. One patient with unsuspected severe coronary artery disease died of complications of myocardial infarction subsequent to a hypotensive episode. Significant phlebitis was also noted at higher doses of drug. This degree of phlebitis could be lessened by diluting the drug in larger volumes of fluid. Three patients experienced diaphoresis, nausea, palpitations, and chest discomfort at the conclusion of the infusions. None of the patients had electrocardiographic changes. Mild fever, alopecia, and nausea and vomiting were noted occasionally. One patient with a hypernephroma and one patient with hepatocellular carcinoma experienced partial responses of their tumors secondary to the drug. Phase II studies of CL216,942 are planned at a starting dose of 260 mg/sq m as a single dose repeated at 21- to 28-day intervals.

Adult↗
PubMed1981

Antigenic changes produced by complex formation between thrombin and antithrombin-III.

Immunization of goats and mules with human thrombin resulted in an antiserum that reacted only weakly with the parent molecule, prothrombin. Some of the antibodies in this antiserum showed a greater affinity for thrombin complexed to its naturally occurring inhibitor, antithrombin-III, than for active thrombin. An antiserum against the human thrombin inhibitor, antithrombin-III, produced 2 precipitin lines against human serum but only 1 against plasma. The 2nd line in serum was shown to represent precipitation of a complex of thrombin with antithrombin-III. The neoantigens appearing in antithrombin-III after complex formation were also present in complexes prepared with purified clotting factor Xa and antithrombin-III. Since purified host (mule) thrombin was also capable of causing formation of the neoantigenic sites when complexed to human antithrombin-III, it seems likely that these determinants result from interaction in the host between the immunogens (either human thrombin or antithrombin) and the appropriate interacting host protein (mule antithrombin-III or thrombin, respectively). Studies by radioimmunoassay showed that the antibodies formed are not completely specific for the neoantigens since they also react to a lesser extent with the free proteins.

Animals↗
PubMed1980

Postcholecystectomy syndrome and its association with ampullary stenosis.

Fifty-six consecutive patients returning with recurrent or persistent upper abdominal pain after cholecystectomy were studied by endoscopic retrograde cholangiopancreatography, abdominal ultrasound and morphine neostigmine test. In 44 patients, pain recurred within 6 months after cholecystectomy. Forty patients were demonstrated on endoscopic retrograde cholangiopancreatography to have moderate to marked ampullary stenosis, which occurred as an isolated abnormality in 32 patients and in association with pancreatitis in 8. Thirteen patients were found to have pancreatitis, and 6 had retained common duct stones. In five patients no definite abnormality was demonstrated. The morphine neostigmine test was positive in 16 of 17 patients with isolated ampullary stenosis and in only 1 of 8 with pancreatitis. This test may be helpful in patients who are to undergo cholecystectomy. In those with positive results, endoscopic retrograde cholangiopancreatography would help assess the size of the ampullary sphincter so that sphincteroplasty could be done at the time of cholecystectomy in appropriate patients.

Abdomen↗
PubMed1980

Mass spectrometer measurement of oxygen uptake and carbon dioxide exchange during cardiopulmonary bypass.

Oxygen uptake (VO2) and carbon dioxide output (VCO2) were measured continuously in four children during cardiopulmonary bypass, using the variation in concentration of a tracer gas, argon, as a measure of flow, and a mass spectrometer to monitor gas concentrations. Normal values for the ratio of VCO2:VO2 (= 0.8) indicated that gas exchange equilibrium had been established following sudden changes in body temperature. During rapid cooling, 10% carbon dioxide is necessary to ensure carbon dioxide homeostasis within the body.

Body Temperature↗
PubMed1980

Dobutamine vs furosemide in the treatment of cardiac failure due to right ventricular infarction.

A 55-year-old man with acute inferior myocardial infarction was shown to have right ventricular involvement based on elevated jugular venous pressure, prominent A waves, and Kussmaul's sign. The ECG showed ST segment elevation in V3R with evolution of Q waves in the inferior leads. Technetium pyrophosphate images showed focal uptake in the inferior region of the left ventricle, and a radionuclide ventriculogram showed a dilated right ventricle. Administration of dobutamine, a potent inotropic agent, was associated with marked hemodynamic improvement. In contrast, the administration of diuretics was associated with hemodynamic impairment.

Blood Pressure↗
PubMed1980

Staining myelin, elastic fibers and nuclei with iron hematoxylin.

Two iron hematoxylin staining procedures were developed. Both use stable stock solutions and can be prepared volumetrically. The nuclear stain is progressive but differentiation is required for myelin sheath and elastic tissue staining. Histochemical procedures demonstrated that acid, hydroxyl, and aldehyde groups play no role in the staining but amine groups are essential. With both types of stains neither electrostatic bonding nor hydrogen bonding is essential but the nature of the union between tissue and the iron hematoxylin complex was not determined.

Animals↗