Search PubMed⌕ Search

Biomedical subjects

W Krivit

Publications and source records attributed to W Krivit.

At least 109 records · Page 6Linked to original sources
PubMed1984

Determination of urinary succinylacetone by capillary gas chromatography.

The average analytical recovery of succinylacetone added to urine and separated by capillary gas chromatography was 69% for solvent extraction and 72% for anion exchange separation. Treating succinylacetone with hydroxylamine hydrochloride at a pH of less than 5 caused formation of a derivative separated by capillary gas chromatography into two isomers: 3-methyl-5- isoxazole propionate and 5-methyl-3- isoxazole propionate as their trimethylsilyl derivatives (molecular weight 227). In a pH greater than or equal to 5, succinylacetone dioxime was formed and separated into 3 isomers as their trimethylsilyl derivatives (molecular weight 404). Succinylacetone dioxime was converted to 3(5)-methyl-(3)5- isoxazole propionate whenever the pH of the solution was dropped to less than 5. Mass spectra of both derivatives are shown. This study demonstrates that capillary gas chromatography is suitable for use in urinary succinylacetone determination.

Amino Acid Metabolism, Inborn Errors↗
PubMed1984

Plasma concentrations of 4-hydroxycyclophosphamide and phosphoramide mustard in patients repeatedly given high doses of cyclophosphamide in preparation for bone marrow transplantation.

Plasma half-life and area under the curve (AUC) values for cyclophosphamide were determined in patients given this agent iv at doses of 50-60 mg/kg/infusion. Apparent plasma half-life and AUC values for the metabolites 4-hydroxycyclophosphamide and phosphoramide mustard were also determined in some of these patients. Disappearance from the plasma of the parent compound as well as that of the metabolites was approximately first-order. Plasma half-life values for cyclophosphamide ranged from 45 to 480 mins; AUC values ranged from 10 to 188 mM X min. As expected, AUC values for cyclophosphamide increased approximately linearly with an increase in its plasma half-life. Apparent plasma half-life values for 4-hydroxycyclophosphamide and phosphoramide mustard increased approximately linearly with an increase in plasma half-life values for cyclophosphamide; the slopes of these relationships were 1.35 and 1.97, respectively, but did not quite extrapolate to zero. AUC values for 4-hydroxycyclophosphamide and phosphoramide mustard remained approximately constant at about 5 and 15 mM X min, respectively, over the relatively wide range of plasma half-life and AUC values obtained for cyclophosphamide. On the basis of these observations we suggest that (a) changes in the rate of cyclophosphamide hydroxylation, effected by whatever means, will not alter the systemic therapeutic and toxic responses to a given dose of cyclophosphamide, given that the cytotoxic effects of this agent are directly proportional to AUC values of 4-hydroxycyclophosphamide and/or phosphoramide mustard, and (b) in most cases, 4-hydroxycyclophosphamide, and not phosphoramide mustard, is likely to be the circulating metabolite of therapeutic importance in humans since the AUC values for phosphoramide mustard exceeded those for 4-hydroxycyclophosphamide by only a factor of 3 and tumor and bone marrow cells proliferating in culture are generally substantially (8-25-fold) more sensitive to 4-hydroxycyclophosphamide.

Adolescent↗
PubMed1983

Bone marrow transplantation for non-Hodgkin's lymphoma in children and young adults. A pilot study.

Allogeneic bone marrow transplantation was performed in 10 patients with disseminated Burkitt's lymphoma or poor-prognosis T-cell lymphoblastic lymphoma. All patients received a cytoreduction regimen consisting of cyclophosphamide, cytosine arabinoside, bis-chloro-nitroso-urea, and total-body irradiation. Eight patients received marrow from HLA-matched sibling donors. One patient received marrow from a parent donor and one patient died during initial cytoreduction and did not undergo total-body irradiation or marrow infusion. Six patients had Burkitt's lymphoma stages III and IV at diagnosis, and three of the six are alive at 18, 28, and 73 months. Four patients had T-cell lymphoblastic lymphoma, stages III and IV at diagnosis, and two of the four are alive at 29 and 49 months. Overall survival in the nine patients who underwent transplantation is 56 percent by life-table analysis. Follow up for the surviving patients ranges from 18 to 73 months (median 29 months). All five survivors are at home with unmaintained remissions.

Adolescent↗
PubMed1983

Intensive therapy followed by bone marrow transplantation for patients with acute lymphocytic leukemia in second or subsequent remission: determination of prognostic factors (a report from the University of Minnesota Bone Marrow Transplantation Team).

Fifteen patients with acute lymphocytic leukemia (ALL) in second or subsequent remission received intensive therapy with cyclophosphamide and single dose, rapid rate (26 cGy/min) total body irradiation (TBI) followed by bone marrow transplantation (BMT) from a histocompatible sibling match. Outcome was compared to that of 23 conventionally treated control patients in second ALL remission who presented to the same institution during the same time period but had no available transplant donor. The 15 BMT patients and 23 control patients had similar characteristics, with the exception that the BMT patients were significantly older at the time of ALL diagnosis (12.6 yr versus 5.7 yr, p = 0.01). BMT patients had a significantly increased chance of remaining disease-free for 36 mo from time on study (43% actuarial versus 5%, p = 0.004) and a greater overall survival rate at 48 mo (47% actuarial versus 9%, p = 0.27) than the conventionally treated patients. In all, 5 of the bone marrow transplant patients (33%) remain alive and free of disease 24-48 + mo from transplantation. Several pre- and posttransplant characteristics were analyzed to determine predictive factors for a successful BMT outcome for patients with ALL in second or subsequent remission. Significant risk factors for predicting leukemic relapse included initial white blood count (WBC) greater than 50,000/microliters at ALL diagnosis (100% relapse rate versus 37% for patients with lower WBCs, p = 0.001) and presence of any extramedullary disease pre-BMT (100% relapse rate versus 37% for patients without extramedullary disease, p = 0.03). All 5 disease-free BMT survivors had initial WBCs less than 50,000/microliters and no evidence of extramedullary disease pretransplantation. Maintenance chemotherapy with 6-mercaptopurine (6MP) and methotrexate was given to four patients starting 100 days after bone marrow transplantation. Use of maintenance chemotherapy was associated with a significantly increased chance of remaining disease free (100% of patients surviving leukemia-free versus 17% for patients not receiving maintenance chemotherapy, p = 0.02). Presence of graft-versus-host disease (GVHD) did not influence leukemia-free survival. These results confirm that intensive therapy followed by bone marrow transplantation is the treatment of choice for patients with ALL in second or subsequent remission who have a histocompatible sibling match. Furthermore, the data suggest that a controlled trial to evaluate the efficacy of maintenance chemotherapy post-BMT for ALL patients is warranted.

Adolescent↗
PubMed1983

Total lymphoid irradiation and cyclophosphamide conditioning prior to bone marrow transplantation for patients with severe aplastic anemia.

A preparative regimen, consisting of total lymphoid irradiation and cyclophosphamide, was utilized in 40 patients with severe aplastic anemia undergoing allogeneic marrow transplantation. This regimen was successful in decreasing rejection in these previously transfused patients, as only one patient rejected the marrow graft. Twenty-nine of the 40 transplanted patients are surviving from 1.5 to 59 mo, with a median follow-up of 24 mo. The actuarial survival rate for these heavily transfused patients with aplastic anemia is 72% at 2 yr. This preparative regimen is extremely effective in decreasing rejection following transplantation for severe aplastic anemia. Future efforts in this area must be aimed at the elimination of graft-versus-host disease and control of fatal infections.

Adolescent↗
PubMed1983

Capillary gas-chromatographic determination of urinary homovanillic acid and vanillylmandelic acid.

This relatively simple, rapid method for quantification of homovanillic acid (HVA) and vanillylmandelic acid (VMA) involves solvent extraction and capillary gas chromatography. With use of this extraction method, the overall analytical recovery from an aqueous solution is 92.5% for HVA and 79.2% for VMA. 3,4-Dihydroxybenzoic acid is the internal standard. Minimal detectable quantities with this method are less than 1 mg/g of creatinine. Capillary gas chromatography produces a chromatogram that is superior to that of packed-column gas chromatography. We also report quantitative results for urinary HVA and VMA in neuroblastoma patients and in normal individuals, demonstrating the diagnostic value of this method.

Adolescent↗
PubMed1982

A randomized study of the prevention of acute graft-versus-host disease.

Acute graft-versus-host disease is a major problem in allogeneic bone-marrow transplantation. We performed a randomized study to compare the effectiveness of two regimens in the prevention of acute graft-versus-host disease. Thirty-five patients received methotrexate alone, and 32 received methotrexate, antithymocyte globulin, and prednisone. Of the patients who received methotrexate alone, 48 per cent had acute graft-versus-host disease, as compared with 21 per cent of those who received methotrexate, antithymocyte globulin, and prednisone (P = 0.01). The age of the recipient was a significant factor in the development of acute graft-versus-host disease: Older patients had a higher incidence of the disease (P = 0.001). We conclude that the combination of methotrexate, antithymocyte globulin, and prednisone significantly decreased the incidence of acute graft-versus-host disease and should be used to prevent this disorder in patients receiving allogeneic marrow transplants.

Acute Disease↗
PubMed1982

Anthracycline cardiomyopathy.

Life-threatening irreversible cardiomyopathy is a major complication of anthracycline therapy, particularly in the pediatric population. The pediatric cardiologist, in concert with the primary oncologist, should therefore play a major role in the care of patients receiving these agents and in clinical trials involving their use. Many risk factors and their relationships to drug pharmacokinetics, mechanisms of action, and toxicity have been identified. These data provide a rational basis for present-day recommendations regarding anthracycline administration and dosage scheduling. They furthermore provide potential avenues for clinical investigation aimed at improving the therapeutic index of these agents: alpha-tocopherol, cytochrome Q10, and other free radical scavengers may decrease the deleterious effects of free radical generation on the myocardium without apparent interference with tumoricidal effect. The cardiac glycosides may decrease cardiac toxicity by specific myocardial exclusion. Anthracycline analogs have been designed to specifically inhibit myocardial binding and/or free radical generation. Clinical trials involving these agents are difficult to interpret because of variability in front end risk factors and dosage schedules in the study population. Furthermore, the relatively low (5 to 10%) incidence of affected patients implies the need for large numbers to demonstrate a statistically significant benefit. Pediatric protocols addressing these issues are urgently needed. Guidelines for present-day management and future studies are outlined.

Animals↗
PubMed1982

The effect of L-asparaginase on antithrombin, plasminogen, and plasma coagulation during therapy for acute lymphoblastic leukemia.

Hemostatic function was studied sequentially in 12 children receiving L-asparaginase, vincristine, and prednisone as remission induction chemotherapy for acute lymphoblastic leukemia. The three-week period of L-asparaginase therapy was characterized by progressive decreases in plasma antithrombin, plasminogen, and fibrinogen concentrations, and by progressive increases in plasma clotting times (prothrombin time, partial thromboplastin time, thrombin time). Platelet counts rose rapidly during the third and fourth weeks of therapy as bone marrow remission was achieved. Factor V levels increased steadily during a five-week period, perhaps related to vincristine or prednisone therapy. Recent reports of thrombosis and hemorrhage in children and adults receiving L-asparaginase may be explained by this complex set of abnormalities in coagulation and coagulation control.

Adolescent↗
PubMed1982

Cholesterol excretion studies in familial hypercholesterolemic children and their normolipidemic siblings.

Twenty children ages 3 to 17 yr, eight with normal lipids and 12 with familial hypercholesterolemia were studied on a metabolic unit for 14 days to evaluate fecal bile acid and fecal neutral sterol excretion. The diet contained a moderately low cholesterol content, 180 to 200 mg/day. Stools were collected in three separate, 3-day pools. Fecal bile acids and fecal neutral sterols were measured using two stool markers and thin-layer, and gas-liquid chromatography techniques. Fecal neutral sterol and fecal bile acid excretion were the same for normal and familial hypercholesterolemic children on a mg/kg basis. Fecal neutral sterols in familial hypercholesterolemic children decreased with age, p less than 0.001; fecal bile acid excretion also appeared to decrease with age, but less significantly, p less than 0.07. Although the familial hypercholesterolemic children have significantly increased plasma and potentially elevated tissue or total body cholesterol, the excretion of fecal bile acids and fecal neutral sterols did not differ between familial hypercholesterolemic and normal children.

Adolescent↗