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Biomedical subjects

S Waldman

Publications and source records attributed to S Waldman.

At least 37 records · Page 2Linked to original sources
PubMed1993

A pilot clinical and pharmacological study of intra-arterial infusion of thiotepa.

Fourteen patients with progressive localized tumors were treated on a clinical and pharmacological study with intra-arterial Thiotepa. A transfemoral percutaneous catheter was inserted into the major artery supplying the tumor. A venous catheter was inserted into the vein draining the tumor area for blood sampling. Doses of Thiotepa ranged from 0.3 mg/kg to 1.0 mg/kg. Courses were repeated monthly and doses of drug escalated as tolerated. Toxicity was mild and doses of drug at least up to 0.9-1.0 mg/kg were tolerable. Pharmacokinetic parameters suggest increasing binding of Thiotepa to tissue when the drug is administered by the intra-arterial route. Clinical responses were observed in a patient with melanoma and in another patient with unknown primary cancer.

Dose-Response Relationship, Drug↗
PubMed1993

Clinical and pharmacological study of intrahepatic artery infusion of thiotepa.

Twenty patients with primary or metastatic liver cancer were treated on a clinical and pharmacological study with intrahepatic artery infusion of Thiotepa. Toxicity was tolerable and included nausea and fatigue. Uncommon side effects were myelosuppression, abdominal pain and anemia. One patient with gallbladder cancer had a partial response for 11 (+) months. Recommended dose of Thiotepa for future Phase II clinical trials is 1.0 mg/kg. Pharmacokinetics of intrahepatic Thiotepa revealed an extraction ratio similar to that reported for cisplatin. The data suggest increased hepatic clearance for Thiotepa either by binding or metabolism.

Aged↗
PubMed1992

Phase I study of high dose 5-fluorouracil and high dose Leucovorin with low dose phosphonacetyl-L-aspartic acid in patients with advanced malignancies.

Twenty-eight patients with refractory advanced malignancies were treated with a 24 hr infusion of 5-fluorouracil (5-FU), Leucovorin (LV), and N-(phosphonacetyl)-L-aspartic acid (PALA) weekly. Twenty-seven patients were evaluable for the assessment of toxicity and anti-tumor activity. PALA was administered as intravenous bolus over 15 min at a fixed dose, 250 mg/m2 24 hr before the start of 5-FU and LV infusions. 5-FU was initially administered at 750 mg/m2 and was incrementally increased to 2600 mg/m2. LV was administered in a fixed dose of 500 mg/m2 concurrently with 5-FU over a 24-hr period. The course was repeated weekly. Diarrhea, stomatitis, nausea, and vomiting were among dose-limiting toxic effects. Other toxicities observed were hand-foot syndrome, hair loss of scalp/eyelashes, overall weakness, rhinitis, and chemical conjunctivitis. Maximum tolerated dose (MTD) of 5-FU in this combination and schedule was 2600 mg/m2. Seven of 14 patients treated at 2600 mg/m2 were able to tolerate the chemotherapy on a weekly basis without interruption. The other seven patients required dose de-escalation, a majority of whom contained 5-FU at a dose of 2100 mg/m2. Twenty-three of 27 patients had been previously treated. Eight patients achieved a partial response, all of whom were previously treated, except three patients. A complete response was observed in a patient with pancreatic carcinoma, previously untreated. Overall response rate for the patients who were treated at the 5-FU dose of 2100 mg/m2 or 2600 mg/m2 is 9 of 18 patients (50%).

Adult↗
PubMed1991

A phase I, II study of high-dose 5-fluorouracil and high-dose leucovorin with low-dose phosphonacetyl-L-aspartic acid in patients with advanced malignancies.

Twenty-eight patients with refractory advanced malignancies were treated with a 24-hour infusion of 5-fluorouracil (5-FU), leucovorin (LV), and N-(phosphonacetyl)-L-aspartic acid (PALA) weekly. Twenty-seven patients were evaluable to assess toxicity and antitumor activity. The PALA was administered as an intravenous bolus over 15 minutes at a fixed dose (250 mg/m2) 24 hours before the start of the 5-FU and leucovorin infusions. Initially the dose of 5-FU was 750 mg/m2; this was increased incrementally to 2600 mg/m2. The LV was administered in a fixed dose of 500 mg/m2 concurrently with the 5-FU over a 24-hour period. This regimen was repeated weekly. Diarrhea, stomatitis, nausea, and vomiting were among the dose-limiting toxicities. Others were hand-foot syndrome, hair loss of the scalp and eyelashes, overall weakness, rhinitis, and chemical conjunctivitis. The maximum tolerated dose of 5-FU in this combination and schedule was 2600 mg/m2. Seven of 14 patients treated with 2600 mg/m2 were able to tolerate the chemotherapy on a weekly basis without interruption. The other seven patients required dose reductions, but most received 5-FU at a dose of 2100 mg/m2. Twenty-three of 27 patients were treated previously. Eight patients had a partial response; five of these were treated previously. A complete response was observed in one patient with pancreatic carcinoma, previously untreated. The overall response rate for patients treated with 2100 or 2600 mg/m2 of 5-FU was nine of 18 patients (50%). Three of four previously untreated patients with pancreatic cancer responded to this treatment (two responded partially, and one had a complete response). One of three heavily pretreated patients with non-small cell lung cancer had a partial response as did a patient with breast cancer. Four of ten patients with colorectal cancer responded to the treatment (four partial responses), of whom three had been treated previously.

Adult↗
PubMed1991

A phase II study of weekly 24-hour infusion with high-dose fluorouracil with leucovorin in colorectal carcinoma.

Twenty-two patients with advanced colorectal carcinoma were enrolled in this study. Ten patients had received prior chemotherapy that included the combination of fluorouracil (5-FU) and leucovorin (LV). All patients required subcutaneous port insertion and portable external infusion pumps to allow outpatient treatment. 5-FU (2,600 mg/m2) was administered concurrently with LV (500 mg/m2) over 24 hours of continuous infusion. The mean steady-state plasma concentration of 5-FU was 10 mumol/L (range, 7 to 14 mumol/L). The 5-FU dose was based on our previous phase I study, in which maximum-tolerated dose (MTD) of 5-FU was determined to be 2,600 mg/m2 in combination with a fixed dose of LV at 500 mg/m2. The treatment was repeated weekly. Twenty-two patients received a total of 560 courses of treatment. Eleven instances of grade 2-3 toxicity were observed: diarrhea (five), stomatitis (three), hand/foot syndrome (three). The overall objective response was 45% (10 of 22) and among previously untreated patients was 58%. Three of the responders achieved complete response (CR), with lung and liver as the metastatic sites. The median duration of survival for the previously untreated patients was not reached at 22 months, and was 10 months for the previously treated patients. These results suggest that short-term infusional therapy of 5-FU and LV in patients with advanced metastatic colorectal cancer generates acceptable toxicity, with equivalent or superior survivability in previously treated and untreated patients versus alternative methods of administration of the two agents.

Adult↗
PubMed1990

Combination chemotherapy and radiotherapy for small-cell carcinoma of the esophagus. A case report of long-term survival and review of the literature.

Small-cell carcinoma of the esophagus is a rare tumor and has received little attention until recent years. It should be differentiated from the far more common poorly differentiated squamous-cell carcinoma of the esophagus, because treatment by surgical resection alone or by radiation therapy results in limited survival of a few months. It is now recognized that esophageal small-cell carcinoma presents with early widespread dissemination and is chemosensitive, similar to primary small-cell carcinoma of the lung. We report on a patient with small-cell carcinoma of the esophagus treated with combination chemotherapy consisting of cyclophosphamide, vincristine, and VP-16 followed by local radiation therapy. Pathologic complete remission was achieved. The patient is currently in remission 22 months after diagnosis, the longest survival reported thus far.

Aged↗
PubMed1988

Effects of nitrovasodilators, endothelium-dependent vasodilators, and atrial peptides on cGMP.

The interactions of the nitrovasodilators, endothelium-dependent vasodilators, and atrial peptides with cGMP synthesis have proved to be useful and important leads to the functions of cGMP and signal transduction mechanisms. Although considerable progress has been made, many important questions remain to be answered. Nevertheless, the guanylate cyclase-cGMP system clearly represents an important second-messenger system that mediates the effects of numerous agents.

Atrial Natriuretic Factor↗
PubMed1987

Effect of in vivo nitroglycerin therapy on endothelium-dependent and independent vascular relaxation and cyclic GMP accumulation in rat aorta.

Vascular relaxation by the organic (nitroglycerin) and inorganic (sodium nitroprusside) nitrovasodilators and the endothelium-dependent vasodilators (acetylcholine and histamine) has been associated with cyclic GMP accumulation. Tolerance to vasodilation by nitroglycerin commonly occurs following prolonged exposure to nitroglycerin. This study investigates the effects of in vivo nitroglycerin therapy on vascular relaxation and cyclic GMP accumulation induced by the nitrovasodilators and the endothelium-dependent vasodilators. Rats were injected with nitroglycerin or the propylene glycol diluent control for 4-7 days. Thoracic aortas from the nitroglycerin-treated rats were 750-fold less sensitive to the relaxant effects of nitroglycerin. In contrast, these aortas were only threefold less sensitive to the relaxant effects of sodium nitroprusside, while the maximum relaxation to acetylcholine and histamine was depressed by 50 and 41%, respectively. Desensitization to relaxation was associated with reduced cyclic GMP elevations to all the vasodilators. Relaxation to 8-bromo cyclic GMP, dibutyryl cyclic AMP, or diltiazem was unaffected by nitroglycerin therapy. Tolerance was also associated with an increased sensitivity to the contractile effects of low concentrations of norepinephrine. This increased sensitivity to norepinephrine was associated with a decrease in cyclic GMP levels. The present results suggest that: (1) desensitization to nitroglycerin, sodium nitroprusside, acetylcholine, and histamine by nitroglycerin therapy may be at the level of cyclic GMP accumulation; (2) cyclic GMP is the common mediator of relaxation induced by the nitro- and endothelium-dependent vasodilators; (3) the mechanisms involved in the activation of guanylate cyclase and relaxation by sodium nitroprusside, acetylcholine, and histamine are probably different than those of nitroglycerin; and (4) cyclic GMP may be acting as a physiological negative feedback signal in agonist-induced contraction.

Acetylcholine↗
PubMed1987

Regulation and role of guanylate cyclase-cyclic GMP in vascular relaxation.

Three classes of vasodilators mediate their effects through the activation of guanylate cyclase and the increased synthesis of cyclic GMP. Nitrovasodilators such as nitroglycerin, nitroprusside, hydroxylamine, azide, etc. result in the generation of the nitric oxide free radical that activates the cytosolic (soluble) isoenzyme form of guanylate cyclase. These agents have been useful in increasing cyclic GMP synthesis in numerous model systems and these effects are independent of extracellular calcium. The increased synthesis of cyclic GMP and the activation of cyclic GMP-dependent protein kinase result in the altered phosphorylation of many smooth muscle proteins including the dephosphorylation of myosin light chain, which is associated with vascular and tracheal smooth muscle relaxation. These latter effects may result from cyclic GMP decreasing cytosolic free calcium concentrations and the activity of myosin light chain kinase. Another class of vasodilators, designated endothelium-dependent vasodilators, includes a long list of agents such acetylcholine, histamine, A23187, ATP, thrombin, etc. that relax vessels only when the endothelium is intact. These agents result in the increased endothelial synthesis and/or release of a factor(s) designated endothelial-derived relaxant factor (EDRF), the structure of which is unknown. This labile factor also activates the soluble isoenzyme form of guanylate cyclase in the smooth muscle resulting in cyclic GMP accumulation and the same cascade of events as above. There is evidence that even under basal, non-stimulated conditions there is EDRF release that influences vascular tone due to the increased synthesis of cyclic GMP. A third class of vasodilators, atrial natriuretic factor (ANF) or atriopeptins, includes a family of peptides that are produced in cardiac atria and other tissues and influence cardiovascular volume and dynamics by causing natriuresis, diuresis, vasodilation and decreased renin, aldosterone and vasopressin secretion. These peptide hormones also increase cyclic GMP synthesis in vascular, renal, adrenal and other tissues. These effects are mediated through specific ANF receptors that couple to and activate the membrane (particulate) isoenzyme form of guanylate cyclase and increase cyclic GMP-dependent protein kinase activity. There are two ANF receptor subtypes in most cells and tissues that are 130,000 and 66,000 daltons. The ANF receptor of about 130,000 daltons, designated receptor ANF-R1 copurifies with particulate guanylate cyclase through numerous procedures and may be part of the membrane-associated guanylate cyclase complex.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1982

Moderate hyperglycemia augments ischemic brain damage: a neuropathologic study in the rat.

We compared the effects of glucose injection with those of saline or mannitol on ischemic brain damage and brain water content in a four-vessel occlusion (4-VO) rat model, which simultaneously causes severe forebrain ischemia and moderate hindbrain ischemia. Glucose given before onset of ischemia was followed by severe brain injury, with necrosis of the majority of neocortical neurons and glia, substantial neuronal damage throughout the remainder of forebrain, and severe brain edema. By comparison, saline injection before forebrain ischemia resulted in only scattered ischemic damage confined to neurons and no change in the brain water content. Mannitol injection before 4-VO or D-glucose injection during or after 4-VO produced no greater forebrain damage than did the saline injection. Morphologic damage in the cerebellum, however, was increased by D-glucose injection given either before or during 4-VO. The results demonstrate that hyperglycemia before severe brain ischemia or during moderate ischemia markedly augments morphologic brain damage.

Animals↗
PubMed1980

Flow-volume loops in newborn infants.

Flow-volume loops were obtained during the performance of crying vital capacity (CVC) maneuvers in 31 infants, 18 of whom had hyaline membrane disease (HMD). Both healthy and distressed infants had flow-volume loops resembling those found in adults with variable intrathoracic obstruction of the central airways. Flow rates during inspiration and expiration increased as the CVC increased. Infants with HMD had narrower inspiratory loops and attained peak expiratory flow later than nondistressed infants, but these differences were not statistically significant. Vocalizations, loss of lung recoil associated with loss of lung volume, and partial collapse of intrathoracic airways may all contribute to the shape of the flow-volume loop in infants.

Humans↗