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Biomedical subjects

E Beutler

Publications and source records attributed to E Beutler.

At least 19 recordsLinked to original sources

A less costly regimen of alglucerase to treat Gaucher's disease.

BACKGROUND: Alglucerase (Ceredase) provides effective enzyme-replacement treatment for patients with Gaucher's disease, but at the usually recommended dose of 60 U per kilogram of body weight every two weeks (130 U per kilogram per month), it costs $382,200 per year for a 70-kg patient. Theoretical considerations suggest that more frequent administration would be more efficient. METHODS: Fourteen patients with type 1 Gaucher's disease that was moderately severe to severe were given 30 U of alglucerase per kilogram per month, in divided doses given either daily or three times weekly, or 120 U given three times weekly. The effect of the treatment on the size of the liver and spleen and on blood counts was compared with published data on patients who received a total dose four to five times as large as the lower dose we used and who received treatment every two weeks. RESULTS: The response to 30 U of alglucerase per kilogram per month, fractionated into three or seven doses weekly, was approximately the same as that reported after the administration every two weeks of a dose four or five times as large, given in the large infusions usually recommended. A fourfold increase in the dose given three times weekly, from 2.3 to 9.2 U per kilogram, did not substantially increase the rate of improvement. CONCLUSIONS: The treatment of Gaucher's disease with smaller total doses of alglucerase given more frequently yields satisfactory results. A dose of 2.3 U per kilogram three times weekly yields major financial benefits with no sacrifice of therapeutic effect. Even taking into account the increased ancillary costs of more frequent administration, this method of administering alglucerase reduces the annual cost of the drug for a 70-kg patient to about $100,000.

Administration, Oral

Sequence of a cDNA clone encoding a rat Reg-2 protein.

We report here the nucleotide sequence of a rat cDNA clone encoding a protein homologous to the Reg (regenerating) protein. The encoded protein, designated Reg-2, shows 60%, 78% and 61% similarities with the reported amino acid sequences of the rat, bovine and human proteins, respectively.

Amino Acid Sequence

2-Chlorodeoxyadenosine: an active agent in the treatment of cutaneous T-cell lymphoma.

Cutaneous T-cell lymphomas are disfiguring malignant lymphoproliferative disorders for which standard therapy has been principally palliative. 2-Chlorodeoxyadenosine (2-CdA), a new purine analogue resistant to degradation by adenosine deaminase that has substantial activity against lymphoid neoplasms, was administered to 16 patients with cutaneous involvement by T-cell lymphoma. All patients had failed topical treatment modalities and/or systemic therapies. Fifteen patients were evaluable; one patient was not evaluable due to incomplete therapy and follow-up. The overall response rate was 47%. Three of 15 patients (20%) achieved complete responses and four of 15 patients (27%) achieved partial responses. The median duration of response was 5 months. One patient remains in unmaintained complete remission at 52+ months. Therapy was well tolerated. Myelosuppression was the principal toxicity encountered, occurring in 8 of 15 (53%) patients. 2-CdA is an effective new agent for the treatment of cutaneous T-cell lymphoma and warrants further study both as a single agent and in combination regimens.

2-Chloroadenosine

New glucose-6-phosphate dehydrogenase mutations from various ethnic groups.

Seven new mutations that produce glucose 6 phosphate dehydrogenase (G6PD) deficiency are described. Three are in variants that were biochemically characterized and described previously, while four were found in samples that had not been characterized biochemically. Several of the mutations affect the amino acids that are mutated in other G6PD variants. As had been noted previously, variants that are associated with nonspherocytic anemia are located either near the glucose 6 phosphate or the NADP binding sites. Variants more distant from these sites are not associated with chronic hemolysis.

Amino Acid Sequence

Molecular abnormalities of a phosphoglycerate kinase variant generated by spontaneous mutation.

A new case of X chromosome-linked phosphoglycerate kinase (PGK) abnormality is described. The male proband was mentally retarded, had behavior disorders, and displayed episodes of hemolytic anemia. The enzyme activity of red blood cells from the patient was about 10% of normal, and that of the cultured fibroblasts was about 50% of normal cells. The variant PGK was characterized by a lower affinity for the substrates, reduced thermostability, and increased anodal electrophoretic mobility. The pH activity profile of the variant enzyme was different from that of normal. The amount of messenger RNA (mRNA) in the variant fibroblasts was comparable to that of normal fibroblasts. The mRNA coding for PGK was subjected to coupled reverse transcription followed by amplification by the polymerase chain reaction. Nucleotide sequence of the variant cDNA showed a point mutation, T/A----C/G transition, in exon 9 of the variant gene. No other mutation was found in all coding regions of the variant. The mutation should cause Cys----Arg substitution at the 315th position from the NH2-terminal Ser of PGK, and it created an additional Ava II (or isoschimatic) cleavage site in the variant gene. Because the variant gene was not detected in the proband's mother and siblings, it must have been generated by spontaneous mutation during oogenesis.

Adult

Gaucher disease: new molecular approaches to diagnosis and treatment.

Gaucher disease is characterized by the accumulation of glucocerebroside, leading to enlargement of the liver and spleen and lesions in the bones. It is caused by an inherited deficiency of the enzyme glucocerebrosidase. Many mutations exist, but four of these account for over 97% of the mutations in Ashkenazi Jews, the population group in which Gaucher disease is the most common. Although there is a strong relation between the mutations and disease manifestations, genetic counseling is made difficult by the fact that within each genotype there is considerable variability in the severity of the disease. Intravenous infusion of glucocerebrosidase is an effective treatment, but the availability of enzyme replacement therapy is limited by its high cost. Marrow transplantation is also effective in treating the disease, but is rarely performed because of the risks involved. In the future gene transfer may become the treatment of choice.

Amino Acid Sequence

Mutations in Jewish patients with Gaucher disease.

DNA from 100 unrelated patients, 97 of whom were Jewish and three half-Jewish, was analyzed for 22 mutations known to cause Gaucher disease. All but seven of the alleles were identified as having previously described mutations. Five of the unidentified mutations proved to be a previously undescribed nucleotide substitution in a splice junction (IVS2+1) that causes skipping of exon 2. Thus, only 2 of 197 alleles remained unidentified. Homozygotes for the most common mutation, that a nucleotide (nt) 1226, manifested, on average, the mildest disease and the latest age of onset. The mutation at nt 84 and the newly described IVS2+1 mutation, which do not produce any enzyme, were associated with earlier onset and more severe disease. Five of the mutations were considered to be "public," in the sense that they were found in more than one unrelated individual. Screening for these five mutations permitted detection of 97.5% of all Gaucher alleles in this patient population. Because the mutation at nt 1226 is underrepresented in the patient population and because not all homozygotes come to medical attention, screening the Ashkenazi population using DNA analysis should detect approximately 99% of all heterozygotes.

Alleles

A new polymorphic site in the G6PD gene.

A polymorphic restriction site has been found in intron 11 of the gene for glucose-6-phosphate dehydrogenase (G6PD). This site is produced by a T----C substitution 13 bp upstream of exon 12, producing an NlaIII restriction site. In various populations there was a strong association between a T at nt 1311 of the G6PD cDNA and the presence of the NlaIII restriction site. Among African Americans, however, the presence of a C at nt 1311 was sometimes associated with the presence of a polymorphic NlaIII site.

Base Sequence

Polymorphisms in the human glucocerebrosidase gene.

The two glucocerebrosidase genes from a patient with Gaucher disease were cloned and 8850 bp of each sequenced. Each clone had a single nucleotide change accounting for the clinical glucocerebrosidase deficiency, an A to G transition at cDNA nucleotide 1226 in one clone, and an insertion of a G at cDNA nucleotide 84 in the other clone. Sequence analysis revealed that there were 11 additional differences between the two clones. The clone with the nt 1226 mutation was, as is always the case, Pv1.1- (polymorphic PvuII site present). The 84GG clone was Pv1.1+. Examination of 35 normal subjects and 51 Gaucher disease patients was consistent with the existence of only two major haplotypes. Two additional minor haplotypes were found, one in Africans and one in the white population. These represented additional mutations superimposed on the basic two haplotypes. Two unrelated patients with Gaucher disease seemed to be exceptions in the 5' end of the gene was heterozygous for the + and - haplotypes but the most 3' marker was homozygous. These patients are believed to have a gene deletion on one allele. In addition to these studies, we correct 28 minor errors in the originally published sequence.

Alleles

The effect of ammonium, phosphate, potassium, and hypotonicity on stored red cells.

The use of an experimental solution that maintained high ATP levels and produced greater than 70 percent viability of stored red cells (RBCs) for up to 18 weeks has been described by other investigators. This solution differed markedly from conventional storage media in that it lacked sodium; contained high concentrations of potassium, ammonium, and phosphate; and was hypotonic. It was not clear which feature or features were responsible for the observed effects. The effects of ammonium, phosphate, potassium, and hypotonicity on stored RBCs have been examined. It was determined that ammonium and phosphate were the important factors in ATP maintenance. The biochemical mechanism by which ammonium acts was studied. In fresh human blood samples, ammonium was found to relieve phosphofructokinase from inhibition by increased ATP concentrations, to have no significant effect on adenine phosphoribosyl transferase activity, and, unexpectedly, to increase the activity of AMP deaminase. Despite prolonged ATP maintenance by ammonium and phosphate-containing storage media, satisfactory viability of RBCs stored up to 77 days was not demonstrated in the rabbit transfusion model.

AMP Deaminase

The molecular biology of G6PD variants and other red cell enzyme defects.

Modern techniques of molecular biology have made it possible to identify mutations in a number of different hereditary red cell enzyme defects. Most of the studies have been performed in glucose-6-phosphate dehydrogenase deficiency, where a large number of point mutations have been identified. The same mutations are encountered repeatedly, even in patients with defects that were thought, on the basis of biochemical properties of the residual enzyme, to be distinct. A beginning has been made in identifying mutations in a few other red cell enzyme defects.

Erythrocytes

Glucose-6-phosphate dehydrogenase variants in Hawaii.

Sequence analysis has been performed on the DNA of 13 glucose-6-phosphate dehydrogenase (G6PD) deficient males from Hawaii, 6 of Filipino, 6 of Laotian, and 1 of Chinese extraction. Four different mutations were found: A-->T at cDNA nt 835, G-->A at nt 871, C-->T at nt 1360, and G-->A at nt 1388. The mutations at nt 835 and nt 1360 have not been described previously, and the latter, in particular, appears to be relatively common. The nt 1360 mutation changes the same codon as is altered in a previously described mutation, G6PD Andalus.

China

Prenatal diagnosis of glucose-6-phosphate-dehydrogenase deficiency.

Prior to the development of the DNA-based technology reliable prenatal diagnosis of G6PD deficiency was not possible. We show that, using PCR amplification and restriction endonuclease digestion, prenatal diagnosis is possible. We have now been able to determine that the male fetus of a mother heterozygous for G6PD Mediterranean had inherited the maternal X chromosome with the normal G6PD gene.

Adult

2-Chlorodeoxyadenosine treatment of low-grade lymphomas.

PURPOSE: Because of the need to identify effective new agents in the treatment of non-Hodgkin's lymphoma and because of the high activity of the purine analog 2-chlorodeoxyadenosine (2-CdA) against chronic lymphocytic leukemia and hairy cell leukemia, a phase II trial of 2-CdA was initiated in patients with low-grade lymphocytic lymphomas. PATIENTS AND METHODS: Forty patients with low-grade lymphocytic lymphomas including diffuse small lymphocytic, follicular small-cleaved, and follicular mixed histologies were enrolled onto the study. Conventional therapies had failed in all patients, and six patients had lymph node biopsies showing evidence of histologic evolution to a higher-grade lymphoma. A total of 107 courses of 2-CdA were administered. There were 27 males and 13 females. The median age was 59 years (range, 37 to 80 years). Patients had received a median of three prior therapies (range, one to six therapies). RESULTS: An overall response rate of 43% was achieved, with eight patients experiencing complete responses (CRs) and nine patients experiencing partial responses (PRs). The duration of responses ranged from 1 to greater than 33 months without maintenance therapy (median duration of response, 5 months). Histology and prior therapy history did not seem to correlate with responses. Significant toxicity was limited to bone marrow suppression; 18% of patients developed neutropenia, and 30% developed thrombocytopenia. CONCLUSIONS: This phase II trial demonstrates that 2-CdA is an effective antilymphocyte, antineoplastic agent with significant activity as a single agent in patients with recurrent or refractory low-grade lymphocytic lymphoma. Responses were achieved with an acceptable toxicity profile. Further trials of this agent in previously untreated patients and in combination regimens are indicated and will be developed.

2-Chloroadenosine