Study of restriction fragment length polymorphisms at the human phenylalanine hydroxylase locus and evaluation of its potential application in prenatal diagnosis of phenylketonuria in Chinese.

Using a human phenylalanine hydroxylase cDNA probe, the restriction fragment length polymorphisms at the human phenylalanine hydroxylase locus have been determined with the restriction enzymes BglII, PvuII, EcoRI + BamHI, MspI, XmnI, HindIII and EcoRV. The frequency of the observed heterozygosity of the restriction site polymorphisms at this locus in a Chinese population is approximately 54%, which is significantly lower than that in Caucasians. No DNA rearrangement or deletion of the phenylalanine hydroxylase locus was detected among mutant phenylalanine hydroxylase genes in seven Chinese classical phenylketonuria (PKU) families.

Screening of congenital hypothyroidism, phenylketonuria, galactosemia, homocystinuria, and maple syrup urine disease in moderate to severe mentally retarded Chinese children.

Five-hundred and fifty one mentally retarded children from seven institutes in Northern Taiwan were screened by dried blood spot for the detection of treatable congenital metabolic diseases, including congenital hypothyroidism, phenylketonuria, homocystinuria, maple syrup urine disease and galactosemia. We found 2 children (0.36%) with congenital hypothyroidism, 1 case (0.

Scrapie-infected murine neuroblastoma cells produce protease-resistant prion proteins.

Scrapie and Creutzfeldt-Jakob disease are transmissible, degenerative neurological diseases caused by prions. Considerable evidence argues that prions contain protease-resistant sialoglycoproteins, designated PrPSc, encoded by a cellular gene. The prion protein (PrP) gene also encodes a normal cellular protein designated PrPC.

Production and Purification of d-Aminoacylase from Alcaligenes denitrificans and Taxonomic Study of the Strain.

A d-aminoacylase-producing microorganism, strain DA181, isolated from soil was identified as Alcaligenes denitrificans subsp. denitrificans. This strain produced about 29,300 units (micromoles of product formed per hour) of d-aminoacylase and 2,300 units of l-aminoacylase per gram of cells (wet weight) when cultivated in a medium containing 1% N-acetyl-dl-leucine as the carbon source.

Prion protein gene expression in cultured cells.

A single copy gene encodes both the scrapie (PrPSc) and cellular (PrPC) isoforms of the prion protein (PrP). Cultured cell lines were found to express the endogenous PrP mRNA at levels comparable to those observed in the brains of adult rodents; however, these cells were invariably found to express greatly reduced levels of PrP. In all the cell lines examined, PrP was undetectable by Western immunoblot analysis.

Mass screening of primary hepatocellular carcinoma by alpha-fetoprotein in a rural area of Taiwan--a dried blood spot method.

A prospective survey of primary hepatocellular carcinoma (PHC) was conducted in a rural area of Taiwan using a two-site enzyme immunoassay for alpha-fetoprotein (AFP) in dried blood samples collected on filter paper. Of 1894 men over 40 years of age who were tested, 20 (1%) had AFP levels of greater than 20 ng/ml of blood on screening. Nineteen of these men received ultrasound examinations, and small PHCs were detected in 4 (21%).

In vitro induction of differentiation in HL-60 leukemic cell line by clerodendron fragrans.

The promyelocytic cell line HL-60 could be induced to differentiate into morphologically and functionally mature monocytoid cells (up to 20%) following exposure to the Chinese herb Clerodendron Fragrans (1 mg/ml). This effect was time dependent and appeared to work synergistically with interferon-r in this promotion of differentiation. Our study suggests that Clerodendron Fragrans has potential therapeutic value for the treatment of certain acute myelocytic leukemia putatively caused by a block in the myeloid differentiation process.

Identification of more than 500 RFLPs by screening random genomic clones.

As part of our genome-mapping effort, we undertook a large-scale screening study to identify RFLPs useful as genetic markers. Some 1,664 single-copy or repeat-containing phage clones from a Charon 4A genomic library were tested for polymorphism against a panel of DNAs, from five unrelated individuals, digested with eight restriction enzymes. Approximately 30% (515) of the clones revealed polymorphism by Southern hybridization; 67 loci detected had PIC values greater than .

Scrapie prion protein contains a phosphatidylinositol glycolipid.

The scrapie (PrPSc) and cellular (PrPC) prion proteins are encoded by the same gene, and their different properties are thought to arise from posttranslational modifications. We have found a phosphatidylinositol glycolipid on both PrPC and PrP 27-30 (derived from PrPSc by limited proteolysis at the amino terminus). Ethanolamine, myo-inositol, phosphate, and stearic acid were identified as glycolipid components of gel-purified PrP 27-30.

Pompe's disease in Chinese and prenatal diagnosis by determination of alpha-glucosidase activity.

We measured the activities of two major forms of alpha-glucosidase in lymphocytes and cultured fibroblasts from normal healthy controls and patients with Pompe's disease by using 4-methylumbelliferyl-alpha-D-glucoside as substrate. We found (1) enzyme activity of the pH 4 and pH 6 forms varied with age, and (2) patients with Pompe's disease showed very low activity of the pH 4 form and a low ratio of pH 4 to pH 6 forms. We established a reference range and were also able to diagnose prenatally the homozygote and heterozygote forms of Pompe's disease which occurred in families of southern Chinese and aborigines in Taiwan.

Two-site enzyme immunoassay for alpha-fetoprotein in dried-blood samples collected on filter paper.

This is a method for measuring alpha-fetoprotein (AFP) in eluates of dried-blood samples on filter paper by use of a simple, sensitive two-site enzyme immunoassay. The spot, 6 mm in diameter (equivalent to about 12 microL of whole blood), is incubated overnight with alkaline phosphatase conjugated to rabbit anti-AFP antibody in a tube containing a polystyrene bead coated with mouse monoclonal antibody to AFP. After the beads are washed the enzyme activities associated with them are determined colorimetrically, with p-nitrophenyl phosphate as substrate.

A Chinese family with phenylketonuria and maternal phenylketonuria detected by family screening.

A 16-year-old boy with classical phenylketonuria (PKU) and mild mental retardation (IQ 69) was detected by the screening of mentally retarded school children in Taiwan with Guthrie's bacterial inhibition assay. The follow-up family study showed that one of his married elder sisters suffered from borderline mental retardation (IQ 75) and was also diagnosed as a classical case of PKU. She had borne one boy and one girl, both suffering from mild mental retardation, microcephaly, delay in linguistic development and severe growth retardation.