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Biomedical subjects

W Krivit

Publications and source records attributed to W Krivit.

At least 91 records · Page 5Linked to original sources
PubMed1985

Acidic metabolites of phenylalanine in plasma of phenylketonurics.

Seven aromatic metabolites of phenylalanine were determined in plasma of 20 patients with classical phenylketonuria by means of capillary gas chromatography. The results obtained showed good correlation with plasma phenylalanine levels. Plasma aromatic acid levels may prove useful in the diagnosis and management of phenylketonuria, as well as in research of this disorder.

Adolescent↗
PubMed1985

Assessment of the diurnal variations in urinary homovanillic and vanillylmandelic acid excretion for the diagnosis and follow-up of patients with neuroblastoma.

The diurnal variation of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) was studied in neuroblastoma patients and in a control group. Urinary HVA and VMA levels in four sequential 6-hour urine collections within a 24-hour period were compared. HVA and VMA levels were expressed in microgram/mg of urinary creatinine (UCr) and in mg/6h specimens. No statistically significant variations between the four time intervals were found when expressed in microgram/mg UCr or mg/6h. The small variations that exist in the excretion of HVA and VMA during different periods of the day are due to variations in renal excretion rather than variations in production. The results from this study indicate that a random urine sample should be as good as a 24-hour collection for diagnosis and follow-up of neural crest tumors.

Child↗
PubMed1985

Pretransplant conditioning with busulfan (Myleran) and cyclophosphamide for nonmalignant diseases. Assessment of engraftment following histocompatible allogeneic bone marrow transplantation.

Four pediatric patients with diseases potentially curable by bone marrow transplantation (BMT)--i.e., common variable immune deficiency, Wiskott-Aldrich Syndrome (WAS), mucopolysaccharidosis type VI, and mucopolysaccharidosis type I received a conditioning regimen consisting of busulfan and cyclophosphamide prior to BMT from HLA-identical, mixed leukocyte culture (MLC)-unreactive siblings. Only one of the four patients achieved full engraftment. Of the remaining three patients, one experienced failure of engraftment, and two had persistent mixed chimerism. Although no serious complications were directly related to the preparative therapy, the doses of busulfan and cyclophosphamide previously described to be adequate for conditioning children with WAS were completely effective in only one of three pediatric patients in this series. Despite a higher dose of busulfan (16 mg/kg), mixed chimerism was observed in a subsequent patient. Of 13 evaluable patients in the literature in whom busulfan and cyclophosphamide had been used as preconditioning regimens for a variety of nonmalignant conditions, eight demonstrated lack of complete and sustained engraftment. On the other hand, clinical improvement has accompanied partial engraftment in some cases. We conclude that additional immunosuppressive and/or myeloablative conditioning is necessary if complete engraftment is attempted in histocompatible allogeneic BMT for many of the nonmalignant disorders.

Adolescent↗
PubMed1985

Intraocular retinoblastoma group V: an analysis of prognostic factors.

A retrospective analysis of the University of Minnesota (Minneapolis) experience with retinoblastoma is presented. Seventy-five patients were diagnosed with retinoblastoma between 1958 and 1983, of which 53 (71%) had at least one Reese-Ellsworth group V eye. Nineteen group V patients and one group II patient developed extraocular disease recurrence. The cumulative actuarial rate of recurrence at 12 years was 36% for patients with group V disease. The median time from diagnosis to recurrence for unilateral patients was seven months and for bilateral patients 28 months (P = .001). Patients developing extraocular disease had a 10-year actuarial survival rate postrecurrence of 34%. The four long-term survivors of extraocular recurrences had had isolated orbital or local soft tissue recurrences only. Features of group V patients associated with extraocular recurrences were identified by univariate life table analyses. Clinical poor-risk factors included the nongenetic form of the disease (P = .03) and male sex (P = .02). Pathologic poor risk factors included rubeosis (P = .01), undifferentiated histology (P = .03), large tumor size (P = .05), and intraocular extension to the anterior segment (P = .02), retinal pigment epithelium (P = .03), choroid (P less than .001), and optic nerve beyond the lamina cribrosa (P = .02). Treatment-associated poor-risk factors included an optic nerve length of less than 5 mm removed at enucleation (P = .003). Multivariate life table analyses demonstrated the following parameters to be independent poor-prognostic factors: optic nerve length of less than 5 mm removed at enucleation (P = .001), optic nerve involvement (P = .004), and large tumor size (P = .01). These results will help to identify patients with retinoblastoma who are at greatest risk for extraocular recurrence.

Actuarial Analysis↗
PubMed1985

Phase II trial of a complex polyriboinosinic-polyribocytidylic acid with poly-L-lysine and carboxymethyl cellulose in the treatment of children with acute leukemia and neuroblastoma: a report from the Children's Cancer Study Group.

Therapeutic efficacy and toxicity were evaluated in 28 children with acute lymphoblastic leukemia, in ten with acute nonlymphoblastic leukemia (ANLL), and in 13 with metastatic neuroblastoma. All were refractory to standard chemotherapeutic agents and 25 were refractory to an investigational drug. The initial dose was 12 mg/m2/day and was based on an established maximal dose tolerated in adults. This dose was found to be intolerable in 5 of 5 children with leukemia. Similarly an initial dose of 9 mg/m2/day was intolerable in 4 of 5 patients with leukemia. The starting dose in the next 28 children with leukemia or neuroblastoma was 3 mg/m2. This drug was gradually increased to the highest tolerated dose by 3-mg/m2 increments. Fifteen children with acute lymphoblastic leukemia, 3 children with ANLL, and 2 children with neuroblastoma received the drug daily. Seven patients with ANLL and 7 patients with neuroblastoma received the drug biweekly. Seventeen patients with acute lymphoblastic leukemia, 6 patients with ANLL, and 5 patients with neuroblastoma had an adequate trial of the drug. An adequate trial was defined as a minimum of 5 weeks of therapy unless progressive disease developed. Side effects of the drug were striking and included fever, hypotension, myalgia, bone pain, arthralgia, arthritis, abdominal pain, liver toxicity, thrombocytopenia, and neurotoxicity. No complete remission occurred although interferon levels above 100 units/ml were induced in nearly 50% of the patients.

Acute Disease↗
PubMed1985

Phase II trial of poly(I,C)-LC, an interferon inducer, in the treatment of children with acute leukemia and neuroblastoma: a report from the Children's Cancer Study Group.

A Phase II study of poly(I,C)-LC was performed in 28 children and adolescents with acute lymphoblastic leukemia (ALL), 10 with acute nonlymphoblastic leukemia (ANLL), and 13 with metastatic neuroblastoma. All were refractory to standard chemotherapeutic agents and 25 to an investigational drug. Initial doses of 12 mg/m2 and 9 mg/m2 were intolerable. However, 9 mg/m2 was tolerable in the majority of patients when the drug was started at 3 mg/m2 and increased by 3 mg/m2 increments. Fifteen children with ALL, three with ANLL, and two with neuroblastoma received the drug daily. Seven patients with ANLL and seven children with neuroblastoma received the drug biweekly. Twenty-eight patients received an adequate trial, which was defined as a minimum of 5 weeks at the maximal tolerated dose, unless there was progressive disease at the maximal tolerated dose. Side effects of the drug were striking, and included fever, hypotension, myalgia, bone pain, arthralgia, arthritis, abdominal pain, liver toxicity, thrombocytopenia, and neurotoxicity. No complete remissions occurred in spite of interferon levels above 100 U in nearly 50% of patients.

Acute Disease↗
PubMed1985

Bone marrow transplantation for acute nonlymphocytic leukemia in first remission: analysis of prognostic factors.

Prognostic factors were reviewed retrospectively for 39 children and adults aged 1 to 40 years (median 14 years) with acute nonlymphocytic leukemia (ANLL) who attained a first remission and underwent bone marrow transplantation from November 1976 to July 1983. The preparation regimen for transplantation was cyclophosphamide (60 mg/kg/d for two days) followed by total body irradiation (either 750 cGy single dose at 26 cGy/min, n = 37, or 1,320 cGy fractionated at 10 cGy/min, n = 2). Twenty-three patients are surviving disease free with a median followup of three years. The three-year estimated disease-free survival is 55% +/- 17% (+/- 2 SE). Five patients have relapsed from 92 to 756 days after transplantation for an estimated relapse rate of 21% +/- 18%. Two factors, the white blood cell (WBC) count and the French-American-British (FAB) classification at leukemia diagnosis were found to be of prognostic importance. Patients with a WBC of less than 20,000/microL at diagnosis had a three-year estimated disease-free survival of 74% +/- 18% v 26% +/- 24% for those with a WBC of greater than or equal to 20,000 (P = .008). The estimated relapse rate was 6% +/- 12% for patients with a WBC at diagnosis less than 20,000 v 53% +/- 38% for patients with a WBC at diagnosis of greater than or equal to 20,000 (P = .01). Patients with myeloid morphology at diagnosis (FAB M1,2,3) had an estimated relapse rate of 9% +/- 12% v patients with monocytoid morphology (FAB M4,5a) whose estimated relapse rate was 58% +/- 44% (P = .05). Our data suggest that a high WBC count at poor prognostic factors for patients with ANLL who undergo bone marrow transplantation in first remission after conditioning with cyclophosphamide plus total body irradiation.

Acute Disease↗
PubMed1985

Value of random urinary homovanillic acid and vanillylmandelic acid levels in the diagnosis and management of patients with neuroblastoma: comparison with 24-hour urine collections.

Urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA) levels were determined in random samples and in 24-hour collections from 13 patients with neuroblastoma and 22 patients without neuroblastoma. Random sample levels were compared with levels in 24-hour collections and showed a positive correlation of 95% for HVA (N = 59) and 93% for VMA (N = 52). No false positives or false negatives occurred using random samples for diagnosis. Nonneuroblastoma (normal) HVA (N = 126) and VMA (N = 119) levels are reported for different age groups. Sequential random HVA and VMA determinations in patients with neuroblastoma during and after therapy are shown. Random urinary HVA and VMA levels are shown to be adequate for utilization in the diagnosis of neuroblastoma and sequential determinations of random HVA and VMA are shown to be helpful in the follow-up of those patients.

Adolescent↗
PubMed1984

Bone-marrow transplantation in the Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI). Biochemical and clinical status 24 months after transplantation.

A 13-year-old girl with the severe form of the Maroteaux-Lamy syndrome (mucopolysaccharidosis Type VI, arylsulfatase B deficiency) has had successful reconstitution with bone marrow from her HLA-MLC-matched sister who had normal arylsulfatase B activity. Full engraftment has been present for 24 months. The following biochemical and clinical changes have occurred: arylsulfatase B activity in peripheral lymphocytes and granulocytes increased to normal levels, and the activity in serial liver-biopsy specimens increased from about 3 per cent of the mean normal level 43 days after transplantation to about 16 per cent at 600 days. Urinary excretion of acid mucopolysaccharide decreased. Ultrastructural evidence of accumulated dermatan sulfate was no longer detectable in bone-marrow cells; in peripheral-blood lymphocytes, granulocytes, or platelets; or in Ito cells of liver. Twenty-four months after engraftment, hepatosplenomegaly was substantially decreased and cardiopulmonary function was normal. Visual acuity and joint mobility were also improved. The patient returned to school and continued to perform well in academic studies. Thus, bone-marrow transplantation provided a source of enzymatically normal cells, which have altered the metabolic and clinical course of the disease.

Adolescent↗
PubMed1984

Capillary gas chromatographic separation of urinary organic acids. Retention indices of 101 urinary acids on a 5% phenylmethyl silicone capillary column.

Gas chromatographic retention indices (methylene units) are reported for 101 urinary organic acids as their trimethylsilyl and oximated trimethylsilyl derivatives on a 5% phenylmethyl silicone fused silica capillary column. Using anion exchange chromatography, organic acids were extracted from urines of five healthy individuals, seven patients with neuroblastoma, and nine patients with inherited organic acidurias. Separation of the various acids was achieved by capillary gas chromatography and identification was done by mass spectrometry using a computerized library search program. All identifications were confirmed by visual comparison with reference mass spectra. Standard deviations of the retention indices for all acids were less than 0.035 methylene units and for 46 acids less than 0.01 methylene units. Three chromatograms of urine from individuals with neuroblastoma, phenylketonuria, and propionic acidemia and one from a healthy individual are shown.

Carboxylic Acids↗