Uptake of copper by mouse hepatocytes.

This study has investigated the uptake of copper by mouse hepatocytes. The cells gave similar results whether they were used right after isolation or maintained overnight on collagen-coated dishes. Uptake from cells in suspension followed two phases: an initial rapid binding followed by a linear uptake phase.

A total extract dot blot hybridization procedure for mRNA quantitation in small samples of tissues or cultured cells.

A simple method for the estimation of specific mRNA concentrations in small tissue samples (as little as 1 mg) or cultured cells (lower limit 10(5) cells) is described. Guanidine hydrochloride extracts of whole cells or tissues are applied directly onto nitrocellulose and hybridized with the appropriate nick-translated probe. Loading according to DNA content allows expression of the result as concentration per cell.

Studies on the mechanism of zinc uptake by human fibroblasts.

The mechanisms of zinc uptake from a complete culture medium by human fibroblasts have been studied. The metal is accumulated in a biphasic pattern; an initial rapid phase followed by a slower linear phase. We suggest that the former represents binding to carriers or receptors on the cell surface followed by uptake to within the cell, or at least to a compartment inaccessible to proteolytic digestion.

Homologous alpha satellite sequences on human acrocentric chromosomes with selectivity for chromosomes 13, 14 and 21: implications for recombination between nonhomologues and Robertsonian translocations.

We report a new subfamily of alpha satellite DNA (pTRA-2) which is found on all the human acrocentric chromosomes. The alphoid nature of the cloned DNA was established by partial sequencing. Southern analysis of restriction enzyme-digested DNA fragments from mouse/human hybrid cells containing only human chromosome 21 showed that the predominant higher-order repeating unit for pTRA-2 is a 3.

Analysis of degradation of the basement membrane protein nidogen, using a specific monoclonal antibody.

A monoclonal antibody was produced against purified nidogen extracted from a mouse basement-membrane-producing tumor. This antibody reacted with a determinant on Nd-40, a rod which separates the globular domains of nidogen. Antigenicity depends on intrachain disulfide bonds within this rod.

Localization of human alpha 1 acid glycoprotein genes to 9q31----34.1.

There is evidence for more than one alpha 1 acid glycoprotein (alpha 1 AGP) gene, and they all appear to be in close proximity. In situ hybridization of the cloned human cDNA p alpha 1AGP-2 to human chromosomes indicates that the alpha 1AGP genes are located between bands q31 and q34.1 on chromosome 9.

The use of restriction fragment length polymorphisms in prenatal diagnosis of dihydropteridine reductase deficiency.

Using a human dihydropteridine reductase (hDHPR) cDNA probe we have detected two AvaII and one MspI restriction fragment length polymorphisms (RFLPs). We show that these RFLPs are in disequilibrium and calculate that approximately 60% of Caucasians are heterozygous for at least one RFLP. We demonstrate the usefulness of these RFLPs in prenatal diagnosis of DHPR deficiency in one family.

Stability of protein and mRNA in human postmortem liver--analysis by two-dimensional gel electrophoresis.

The method of two-dimensional polyacrylamide gel electrophoresis has been used to investigate the post mortem stability of protein and mRNA in human liver. The electrophoretic mobility of proteins and of the in vitro translation products of the mRNA were found to be essentially unaffected by incubation of the liver at 37 degrees C for up to 2 h or at 4 degrees C for up to 16 h. This study indicates that the major protein and mRNA species in liver are stable enough following death to allow meaningful studies on tissue collected under standard autopsy conditions.

Albumin has no role in the uptake of copper by human fibroblasts.

The mechanism of copper uptake by cells has been the subject of controversy for some time. This paper examines the possibility of a role for albumin in the uptake of copper by fibroblasts. Although the cells could accumulate copper from a copper-albumin complex, there was no evidence for either copper-albumin or albumin receptors on the cell surface.

Localization of the human dihydropteridine reductase gene to band p15.3 of chromosome 4 by in situ hybridization.

We report the localization of the gene for dihydropteridine reductase (DHPR) to the human chromosome region 4p15.3 by in situ hybridization using a cDNA probe to the enzyme. The distal end of the short arm of chromosome 4 is of considerable interest because the gene responsible for Huntington's disease is located in this region.

Episodes of severe metabolic acidosis in a patient with 3-methylglutaconic aciduria.

Persistent excretion of 3-methylglutaconic acid was found in a 6-month-old infant with multiple minor physical malformations and delayed development. During two episodes of intercurrent viral illness, the patient developed severe metabolic acidosis and excreted large amounts of lactate, 3-hydroxybutyrate and acetoacetate. The excretion of 3-methylglutaconic acid did not change during these episodes, nor did it increase following leucine loading.

Genomic organization of human centromeric alpha satellite DNA: characterization of a chromosome 17 alpha satellite sequence.

We characterized a recombinant clone E7 containing a 1.6-kb Eco RI insert of human alpha satellite DNA (alpha DNA) which hybridized in situ predominantly to the centromere of chromosome 17. Three thousand copies of this sequence were detected on chromosome 17, although a lesser number of copies were also found on the centromeres of chromosomes 11, X, and the other human chromosomes, except Y.

Future developments in phenylketonuria.

Treatment of classical phenylketonuria (PKU) is very good, but problems still exist in regard to the duration of treatment and a means of ensuring that all women with PKU recommence dietary treatment before becoming pregnant. A 'one-shot' cure of the disease remains desirable and may become available in the more distant future by somatic cell gene therapy. Insertion of a normal gene or correction of the defective gene at the normal site in the chromosome and in liver cells is likely to be necessary both technically and ethically.

A differentiation-defective concanavalin-A-resistant variant of a pluripotent embryonal carcinoma cell line.

A concanavalin-A(Con A)-resistant variant of the pluripotent mouse embryonal carcinoma cell line, PSA1-NG2, was isolated. This variant, designated NG2-2.16, fails to exhibit the extensive spontaneous differentiation displayed by PSA1-NG2 in colonies in vitro and in tumours in vivo.