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Biomedical subjects

I K Brandt

Publications and source records attributed to I K Brandt.

13 recordsLinked to original sources
PubMed1979

Structural comparison of hexosaminidases in primates.

1. beta-Hexosaminidase (hex) structure was compared in various primates, using thin-layer isoelectric focusing on polyacrylamide gels and quantitative microcomplement fixation. 2. Isoelectric focusing revealed no intraspecies differences and similar interspecies patterns. 3. Hex A and B are evolving at a moderate, but equal, rate and in a manner consistent with accepted phylogenetic patterns. 4. Quantitative microcomplement fixation revealed a closer homology between human hex A and chimpanzee A or human hex B and chimpanzee hex B than between human hex A and human hex B.

Animals↗
PubMed1979

Linkage analysis using heterozygote detection in phenylketonuria.

This linkage investigation was undertaken utilizing an improved method for phenylketonuria (PKU) heterozygote detection. This method is based on studies of semi-fasting, noon-time, blood specimens obtained from 85 obligate heterozgotes and 45 controls who were neither pregnant nor on birth control medication. The best separation between heterozygotes and normals was achieved with a discriminant function involving the logarithms of the serum concentrations of phenylalanine, tyrosine and tryptophan. The theoretical overlap area between the distributions of heterozygotes and controls, based on the above function, was between the distributions of heterozygotes and controls, based on the above function, was 3.75%. In 19 obligate heterozygotes and 13 controls who were either pregnant or on birth control medication, the best separation was achieved with a discriminant function involving the logarithms of the serum concentrations of phenylalanine and tyrosine. The theoretical overlap area was 8.23%. These equations identified heterozygotes with sufficient accuracy to permit efficient genetic linkage analysis. We were unable to demonstrate genetic linkage between the PKU locus and 15 common blood, serum, and urinary markers. All but loose linkage (theta greater than 0.3) was excluded for Rh, ABO, Gc, Kidd, and AP. Moderate linkage exclusion (theta less than 0.2) was shown for PGM, Duffy, Hp, MNS, HL--A, and Kell. Close linkage (theta less than 0.1) was excluded for Amy2, 6PGD, P, and ADA. We were unable to find linkage heterogeneity between the Amish and non-Amish populations.

Chromosome Mapping↗
PubMed1978

Phenylketonuria heterozygote detection in families with affected children.

Improved approaches to the problem of heterozygote detection for phenylketonuria (PKU) were developed in this study. The discrimination was based on 85 obligate heterozygotes and 45 controls who were neither pregnant nor on birth control medication. The best separation between hetrozygotes and normals was achieved with a linear discriminant function involving the logarithms of the serum concentrations of phenylalanine, tyrosine, and tryptophan. The theoretical overlap area between the distributions of heterozygotes and controls based on the above function, was 3.75%. In the 19 obligate hetrozygotes and 13 controls who were either pregnant or on birth control medication, the best separation was achieved with a linear discriminant function involving the logarithms of the serum concentrations of phenylalanine and tyrosine. The theoretical overlap area was 8.23%. The genetic accuracy of the discriminant function was confirmed by testing the results with parental-child exclusions, segregation analysis, and the frequency of heterozygosity in nonrelated collateral spouses. Finally, there was evidence suggesting that the antihypertensive agent, aldomet, alters serum tyrosine and tryptophan levels.

Ethnicity↗
PubMed1977

The Chicago variant of clinical galactosemia.

A new variant of clinical galactosemia with two hitherto unidentified alleles on the transferase locus in one family is described. This new clinical variant of transferase has 25% of normal control activity in blood and in skin fibroblasts, and the patient accumulates galactose-1-phosphate in blood on an unrestricted galactose diet. Using starch gel electrophoresis on the hemolysate of the family members, a fast-moving transferase with mobility in between those of the normal control and of the Duarte variant is identified. This new allele is designated as GALTC1 (fast-moving Chicago variant). In addition, a second new allele was documented in this family by studying the instability of the transferase enzyme in hemolysates of family members at 50 degrees C for various time intervals. This new allele is designated as GALTC2 (heat-labile Chicago variant). On the basis of these studies, the transferase genotype of this patient is thought to be a double heterozygote compound, GALTC1/GALTG.

Alleles↗
PubMed1977

Unusual association of Saethre-Chotzen syndrome and congenital adrenal hyperplasia.

This report describes and discusses the very rare occurrence of two heritable traits, the Saethre-Chotzen syndrome and congenital adrenal hyperplasia (21 hydroxylase deficiency, salt-losing type) in a female infant whose father presents the clinical manifestations of Saethre-Chotzen syndrome. Family study revealed no other instances of the recessively inherited adrenogenital syndrome. Other literature cases combining acrocephalosyndactyly and urogenital anomalies are discussed and compared.

Acrocephalosyndactylia↗
PubMed1977

Acrodysostosis coinciding with pseudohypoparathyroidism and pseudo-pseudohypoparathyroidism.

The diagnosis of acrodysostosis has been differentiated from that of pseudohypoparathyroidism or pseudo-pseudohypoparathyroidism by the absence of endocrine abnormalities, more generalized osseous abnormalities, and a characteristic facial appearance. Two cases are presented which fulfill all of the major features of acrodysostosis: peripheral dysostosis, nasal hypoplasia (pug nose), and mental retardation. The first case had all the metabolic abnormalities of pseudohypoparathyroidism; the second case had urinary cyclic adenosine-3',5'-monophosphate findings suggestive of pseudo-pseudohypoparathyroidism. Therefore acrodysostosis cannot be differentiated from pseudohypoparathyroidism or pseudopseudohypoparathyroidism on clinical and radiologic features only.

Adult↗
PubMed1976

Hurler syndrome: alpha-L-iduronidase activity in leukocytes as a method for heterozygote detection.

Alpha-L-Iduronidase activity and beta-galactosidase activity were determined in mixed leukocyte preparations in 10 families in which the Hurler syndrome had occurred. Affected patients, heterozygotes, and normal subjects were clearly distinguished by alpha-L-iduronidase activity alone. Patients had 0-3%, obligate heterozygotes 19-60%, and normal subjects 83-121% of the mean normal activity. There was no overlap between heterozygotes and normal subjects. Although the mean alpha-L-iduronidase to beta-galactosidase ratio was significantly lowered in heterozygotes when compared with that of normal subjects, appreciable overlap was noted between the two groups.

Adolescent↗
PubMed1975

An artifact in the gas chromatographic analysis of urinary organic acids from phenylketonuric children: decarboxylation of the phenylpyruvic acid during extraction.

Phenylpyruvic acid is converted at least partially to phenylacetic acid during the normal extraction procedure used to obtain urinary organic acid profiles of phenylketonuric children by gas chromatography. This decarboxylation reaction can be reduced or completely eliminated by forming oxime derivatives prior to extraction.

Child↗