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Biomedical subjects

R Wallach

Publications and source records attributed to R Wallach.

18 recordsLinked to original sources
PubMed2005

Soil water repellency induced by long-term irrigation with treated sewage effluent.

This study describes soil water repellency developed under prolonged irrigation with treated sewage effluent in a semiarid environment. Soil surface layer (0-5 cm) and soil profile (0-50 cm) transects were sampled at a high resolution at the close of the irrigation season and rainy winter season. Samples from 0- to 5-cm transects were subdivided into 1-cm slices to obtain fine scale resolution of repellency and organic matter distribution. Extreme to severe soil water repellency in the 0- to 5-cm soil surface layer persisted throughout the 2-yr study period in the effluent-irrigated Shamouti orange [Citrus sinensis (L.) Osbeck cv. Shamouti] orchard plot. Nearby Shamouti orange plots irrigated with tap water were either nonrepellent or only somewhat repellent. Repellency was very variable spatially and with depth, appearing in vertically oriented "repellency tongues." Temporal and spatial variability in repellency in the uppermost 5-cm soil surface layer was not related to seasonality, soil moisture content, or soil organic matter content. Nonuniform distribution of soil moisture and fingered flow were observed in the soil profile after both seasons, demonstrating that the repellent layer had a persistent effect on water flow in the soil profile. A lack of correlation between bulk density and volumetric water content in the soil profile demonstrates that the observed nonuniform spatial distribution of moisture results from preferential flow and not heterogeneity in soil properties. Soil water repellency can adversely affect agricultural production, cause contamination of underlying ground water resources, and result in excessive runoff and soil erosion.

Citrus sinensis↗
PubMed1999

A phase II double-blind randomized study of the simultaneous administration of recombinant human interleukin-6 and recombinant human granulocyte colony-stimulating factor following paclitaxel and carboplatin chemotherapy in patients with advanced epithelial ovarian cancer.

PURPOSE: Recombinant human interleukin-6 (rhuIL-6) is a glycosylated cytokine with hematopoietic stimulatory effects. In particular, preclinical studies suggest the agent can stimulate thrombopoiesis, even in conjunction with chemotherapy. We attempted to determine whether higher dose chemotherapy for ovarian cancer was possible given the pharmacologic use of this important growth factor. METHODS: We conducted a randomized, double-blind phase II study of IL-6 plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in combination with a standard chemotherapy regimen. Patients with epithelial ovarian cancer, stages Ic to IV, were eligible. All patients were previously untreated with chemotherapy and had Karnofsky performance status >/=60. rhuIL-6 (Escherichia coli, SDZ ILS 969) 1.0 micrograms/kg or placebo was given subcutaneously on days 2-8 every cycle together with G-CSF 5.0 micrograms/kg subcutaneously days 2-15, following administration of paclitaxel 175 mg/m2 as a 3-h infusion and carboplatin given to a desired AUC of 7.5 on day 1 every 21 days. RESULTS: Fifty patients were entered in this study, although the study was temporarily suspended by the FDA in midstudy over manufacturing concerns. Therefore, 37 patients were evaluable for efficacy of growth factor; 19 patients received placebo plus G-CSF and 18 rhIL-6 plus G-CSF. There was no difference in prognostic variables between these two groups. Platelet nadirs were lower in the first cycle for the placebo group (P = 0.004, Wilcoxon sum-rank test) but not in other cycles. There was no statistically significant difference in cycle treatment delays, carboplatin dose delivered, number of patients with grade 4 thrombocytopenia, or platelet transfusion. Nonetheless, the trend of the data favored IL-6 in all cases. CONCLUSIONS: This study demonstrated a minimal effect (statistically significant in the first cycle only) on thrombopoiesis in women undergoing paclitaxel and carboplatin therapy of ovarian cancer. No clinically significant effect on actual chemotherapy delivery was demonstrated, however. Future studies, if warranted, to ameliorate thrombocytopenia should be carried out with regimens producing even greater thrombocytopenia than the current regimen in the control arm.

Adenocarcinoma↗
PubMed1999

Activity and pharmacodynamics of 21-Day topotecan infusion in patients with ovarian cancer previously treated with platinum-based chemotherapy. New York Gynecologic Oncology Group.

PURPOSE: Twenty-one-day topotecan infusion was administered as second-line therapy in patients with previously treated ovarian cancer (based on our prior favorable phase I experience) to determine its activity, time to progression, and pharmacodynamics. PATIENTS AND METHODS: Ovarian cancer patients with measurable lesions and one prior platinum-containing regimen were eligible. Topotecan 0.4 mg/m(2)/d 21-day continuous ambulatory intravenous infusion, with appropriate dose modifications for toxicity, was administered every 28 days. Weekly blood levels of topotecan and topoisomerase-1 (topo-1) levels in peripheral-blood mononuclear cells (PBMCs) were determined for pharmacodynamic correlation. RESULTS: Twenty-four patients were entered onto the study (six cisplatin-refractory, five relapsing within < 6 months and 13 relapsing > 6 months after platinum-based therapy). A total of 128 cycles of topotecan (median, four cycles per patient; range, one to 12 cycles) were administered. The major toxicity was neutropenia (29% grade 3 in all cycles and 4% grade 4). One episode of grade 4 thrombocytopenia (4%) occurred. Fifty-two percent of the patients had anemia that required transfusions. Eight of 23 patients with measurable disease (35%; 95% confidence interval [CI], 15% to 54%) had partial responses (PRs) lasting longer than 1 month. Two of these patients had minor residual computed tomographic changes but had clinical complete remissions that lasted up to 53 weeks while they were not undergoing further therapy. One patient with nonmeasurable disease had a PR (by CA-125 criteria) that lasted 6 months, for an overall response rate of 38% in nine of 24 patients (95% CI, 18% to 57%). The median time to progression was 26 weeks. Pharmacodynamic analysis demonstrated a statistically significant decrease in free PBMC topo-1 level at weeks 2 and 3 of drug administration. There was a strong statistical correlation between the decrease in free topo-1 levels and increasing area under the curve (AUC) for topotecan. This was confirmed in a pharmacodynamic model. CONCLUSION: Twenty-one-day infusion is a well-tolerated method of administering topotecan. Pharmacodynamic studies demonstrate correlations between (1) the week of infusion and the PBMC topo-1 level, (2) the AUC of topotecan and the decrease in topo-1 levels, and (3) the change in topo-1 level and the neutrophil nadir. The objective response rate of 35% to 38% (95% CI, 15% to 57%) in this small multicenter study is at the upper level for topotecan therapy in previously treated ovarian cancer. Prolonged topotecan administration therefore warrants further investigation in larger, randomized studies comparing this 21-day schedule with the once-daily-for-5-days schedule.

Adult↗
PubMed1995

A phase I trial of cyclosphosphamide and carboplatinum combined with interleukin-3 in women with advanced-stage ovarian cancer.

The hematopoietic growth factor, recombinant human interleukin-3 (rhu IL-3), stimulates production of both leukocytes and platelets, and thus potentially has greater utility than growth factors that solely stimulate leukocytes production when employed with dose-intensive chemotherapeutic regimens. To determine the optimal schedule for administration of rhu IL-3 in combination with cyclophosphamide and carboplatin, an aggressive regimen for the treatment of advanced ovarian cancer, a phase I trial was initiated by the New York Gynecologic Oncology Group. Following surgical debulking, all patients received cyclophosphamide and carboplatin for 6 cycles. rhu IL-3 was administered at 50, 250, or 500 microgram subcutaneously for 5 days either immediately prior to or after administration of chemotherapy. Cohorts of six patients were treated at each dose level (three pre- and three postchemotherapy). Eighteen patients received 91 cycles of treatment. The major toxicities attributable to rhu IL-3 included fevers, chills, malaise, nausea, and headache, but were not dose-limiting at the doses of rhu IL-3 employed. The major finding of this study was that rhu IL-3 administered after chemotherapy offered greater platelet protection than rhu IL-3 administered prior to chemotherapy as assessed by median platelet nadir and duration of platelet counts < 50,000/mm3. A second major finding was a dose-response relationship for rhu IL-3: the two higher doses employed, 250 and 500 micrograms, offered more effective platelet protection than the lower dose employed, 50 micrograms. rhu IL-3 had no significant effects on leukocyte nadirs or duration of nadirs at any schedule or dose employed. rhu IL-3 may reduced the thrombocytopenia associated with aggressive treatment with cyclophosphamide and carboplatin, although this remains to be confirmed in a randomized, placebo-controlled trial. The effects of rhu IL-3 are dose- and schedule-dependent.

Adult↗
PubMed1991

Hexamethylmelamine for the treatment of ovarian cancer--the Mount Sinai experience.

Two regimens were tested, CHAP I and CHAP II, the latter, a hexamethylmelamine dosage-intensive regimen, first as second line (salvage) therapy and then as primary therapy. Both produced the most successful results achieved in the Mount Sinai series up to the time of their introduction, when compared to their predecessor regimens: CAP, AP and P. In an overall interim comparison, CHAP II was significantly superior to historical AP and CAP as primary therapy, as was CHAP I vs. AP in several important subgroups compared as part of a randomized trial. CHAP II overall progression-free survival was improved in spite of added new sensitive test methods. Salvage therapy also improved markedly with the addition of intensive hexamethylmelamine. Several biological and treatment characteristics strongly influenced outcome, especially young age and adding hexamethylmelamine. Other possible factors included: poor tumor grade, poor performance status, and extent of surgical debulking, even to intermediate residual, 2-6 cm size [CHAP II only]; extensive (optimum) surgery [CHAP I only]. The hexamethylmelamine-containing regimens interact favorably with some of these factors, better than did the preceding regimens. Five-year follow-up analyses weakened slightly for extensive surgery, intermediate size and poorly differentiated tumors. It confirmed and strengthened several findings favoring CHAP I & II, the hexamethylmelamine-containing regimens.

Altretamine↗
PubMed1988

Chrysiasis: transmission electron microscopy, laser microprobe mass spectrometry and epipolarized light as adjuncts to diagnosis.

Two patients receiving gold therapy for rheumatoid arthritis developed skin pigmentation, chrysiasis, which in one appeared 4 months after cessation of the therapy. The diagnosis was confirmed by transmission electron microscopy and mass spectrometry laser microprobe analysis of paraffin sections and its extent demonstrated by epipolarized light. The condition is poorly reported and clinically may be confused with silver and mercury impregnation. Tissue diagnosis requires ancillary methods and of these, transmission electron microscopy and laser microprobe mass spectrometry are excellent examples. The transmission electron microscopy findings differ from previous reports and raise doubts on the hypothesis on the role of the skin in gold excretion. Because of the renewed interest in crysotherapy and the latent period that can separate this from chrysiasis, an increase in chrysiasis and the need for its diagnosis can be anticipated.

Arthritis, Rheumatoid↗
PubMed1986

Apert syndrome and fetal hydrocephaly.

Apert (1906) was the first to identify a syndrome characterized by the association of acrocephaly with syndactyly, acrocephalosyndactylism. Since then Apert syndrome has been recognized as a clinical entity. Although hydrocephalus was rarely reported as an associated malformation, it was suggested that hydrocephalus might be responsible for mental retardation in some cases of Apert syndrome. We report a case of Apert syndrome presenting as fetal hydrocephaly at 28 weeks gestational age, and we review the literature. We suggest that hydrocephalus should be considered as a major associated malformation, and a complete evaluation with sonogram and computed tomography scan is recommended in any newborn suspected of having Apert syndrome after routine cephalometric measurement.

Abnormalities, Multiple↗
PubMed1980

Pathogenesis of paroxysmal hypertension developing during and after coronary bypass surgery: a study of hemodynamic and humoral factors.

A prospective study of hypertension first appearing during and after saphenous vein bypass coronary surgery was performed in 28 patients to examine the incidence, hemodynamics and mechanism of this problem. In 15 patients (54 percent) new hypertension developed (mean arterial pressure greater than 107 mm Hg), characterized by increased peripheral vascular resistance and unchanged cardiac output within 1 hour after surgery. These 15 patients had a longer history of angina of greater severity, but also had relatively well preserved ventricular myocardium. Because plasma renin activity was depressed in patients in the hypertensive group, activation of the renin-angiotensin system was not important in the pathogenesis of this postoperative hypertension. The expected decrease in total peripheral resistance at the onset of cardiopulmonary bypass was observed in all patients, but later during bypass the peripheral resistance increased in all patients in association with a rise in plasma epinephrine levels. Patients who had hypertension postoperatively had a greater increase in arterial pressure and total peripheral resistance during cardiopulmonary bypass than did those with normal postoperative blood pressure. An elevation in plasma epinephrine and norepinephrine concentration, suggesting enhanced sympathoadrenal responsiveness to the challenge of cardiopulmonary bypass, was characteristic of the hypertensive group. This evidence of enhanced sympathetic activity during surgery may be a useful predictor of the development of postoperative hypertension.

Blood Pressure↗
PubMed1978

Combination chemotherapy for ovarian carcinoma with cyclophosphamide, adriamycin, and cis-dichlorodiammineplatinum(II) after failure of initial chemotherapy.

Twenty-four patients who had stage III or IV ovarian adenocarcinoma and had failed prior chemotherapy were treated with cyclophosphamide, adriamycin, and cis-dichlorodiammineplatinum(II) every 3 weeks. Twelve patients had objective responses and an additional six had subjective improvement. The median duration of survival for responders is 9 months. There were no instances of nephrotoxicity. Fluid management consisted of 1000-2000 ml of iv fluid without Lasix- or mannitol-induced diuresis. Patients responded after having failed radiotherapy or multiple-drug chemotherapy, including some who were 70-75 years of age or were greater than 50% bedridden. Patients with one- or two-drug prior chemotherapy had a higher response rate (ten responses among 17 patients) than those previously treated with three or more drugs (two responses among seven patients).

Adenocarcinoma↗
PubMed1972

Angiotensin II vascular receptors: their avidity in relationship to sodium balance, the autonomic nervous system, and hypertension.

During intravenous administration of varying doses of angiotensin II antibody to anesthetized rats, apparently specific vascular receptors were characterized. These receptors compete with administered antibody to bind circulating angiotensin. This competitive phenomenon was used to evaluate the affinity of these receptors for angiotensin. Apparent vascular receptor affinity was defined by the amount of antibody required to block the blood pressure response to exogenous angiotensin. It was found that this receptor affinity varies directly with sodium intake so that the amount of antibody required to block was eightfold greater in normal animals on a high sodium intake, as compared with those on a low sodium intake. Sodium dependence of receptors was also demonstrated in nephrectomized animals, in desoxycorticosterone (DOC)-treated rats, and in chronic renal hypertension. Thus the observed changes in receptor affinity were usually inversely related to measured endogenous angiotensin II levels. Ganglionic blockade increased antibody requirement eightfold. All of these changes were consistent, with no overlap observed in response of individual animals from different groups. These results may explain the variation in pressor activity of angiotensin associated with changes in salt balance and ganglionic blockade. In general, when sufficient antibody was injected to block the effect of exogenous angiotensin a blood pressure lowering effect was also observed. Two exceptions were the nephrectomized and the one-kidney renal hypertensive animals, in both of which antibody administration had no effect on blood pressure. Additional results suggest that changes in receptor affinity are involved in the pathogenesis of various types of experimental hypertensions because the amount of antibody required to block angiotensin was enhanced in renal (twofold), DOC (fourfold), and genetic (fourfold) hypertension. Accordingly, changes in the affinity of these receptors could be critically involved in normal blood pressure control and in various forms of experimental and clinical hypertension, even when circulating angiotensin II levels are normal.

Angiotensin II↗
PubMedDate not supplied

Paraplegia associated with intraaortic balloon pump counterpulsation.

Two patients developed paraplegia associated with the use of the intraaortic balloon pump. In one patient, transient spinal ischemic episodes ceased after removal of the intraaortic balloon and the second patient apparently sustained spinal cord infarction. Possible etiologic mechanisms include vascular occlusion due to balloon position, arterial spasm, thromboembolic phenomena, hypotension, hypoxia and arterial dissection.

Aged↗
PubMedDate not supplied

BRCA1 germline mutation presenting as an adenocarcinoma of unknown primary.

BACKGROUND: The work-up of adenocarcinoma of unknown primary usually includes history, physical examination, radiographic imaging, tumor markers, and more recently molecular and genetic information. We report here on how the suggestion by family history of a BRCA1 mutation guided the diagnostic and therapeutic approach in a patient with metastatic carcinoma of unknown primary. METHODS: BRCA1 mutation was screened for by polymerase chain reaction (PCR) and single-strand conformational polymorphism analysis. Primers for PCR amplification included selected BRCA1 exons 2, 110, 11L, 13, and 20. The PCR product was cloned into a PCRII vector and sequenced with a Sequenase Version 2.0 Sequencing Kit. RESULTS: Single-strand conformational polymorphism analysis suggested a mutation in the region of exon 20 and sequencing confirmed the presence of a germline mutation 5382insC. CONCLUSIONS: This case illustrates an unusual presentation of adenocarcinoma of unknown primary in a patient with a germline BRCA1 mutation, the use of a suspected germline mutation to guide the work-up and treatment, and finally the value of positron emission tomography scanning in the work-up of an unknown primary.

Adenocarcinoma↗