Genotyping of alcohol dehydrogenase at the ADH2 and ADH3 loci by using a polymerase chain reaction and restriction-fragment-length polymorphism in Chinese alcoholic cirrhotics and non-alcoholics

We investigated the genotype of ADH2 and ADH3 in Chinese alcoholic cirrhotics and non-alcoholics by using a polymerase chain reaction and restriction-fragment-length polymorphism. This method is non-radioactive, easy to implement with good reproducibility. In the Chinese population, the frequencies of the ADH2*1 and ADH3*2 alleles were significantly higher in the alcoholic cirrhotic patients (53%; 23%) than in the viral hepatitis cirrhotics (32%; 8%) and the gastric and/or duodenal ulcer control patients (25%; 6%). On the other hand, the gastric and/or duodenal ulcer control patients and the viral hepatitis cirrhotic patients showed similar allele frequencies for the polymorphic ADH2 and ADH3 genes. These findings suggest that the alleles ADH2*2 and ADH3*1, coding for the high-Vmax beta 2-ADH and gamma 1-ADH, respectively, may play a protective role against alcoholism in Chinese patients.

Nucleoside analogues previously found to be inactive against HIV may be activated by simple chemical phosphorylation

Nucleoside analogues previously found to be inactive against the human immunodeficiency virus (HIV) may be activated by simple chemical derivatisation. As part of our effort to deliver masked phosphates inside living cells we have discovered that certain phosphate triester derivatives of inactive nucleoside analogues become inhibitors of HIV replication. This discovery underlies the importance of the masked phosphate approach, and has significant implications for the future design of chemotherapeutic nucleoside analogues. If highly modified nucleoside analogues may be active without the intervention of nucleoside kinase enzymes, major advantage may accrue in terms of low toxicity and enhanced selectivity. Moreover, the increased structural freedom may have implications for dealing with the emergence of resistance. The concept herein described as 'kinase bypass' may thus stimulate the discovery of a new generation of antiviral agents.

Identification of a human stomach alcohol dehydrogenase with distinctive kinetic properties

A new form of alcohol dehydrogenase, designated mu-alcohol dehydrogenase, was identified in surgical human stomach mucosa by isoelectric focusing and kinetic determinations. This enzyme was anodic to class I (alpha, beta, gamma) and class II (pi) alcohol dehydrogenases on agarose isoelectric focusing gels. The partially purified mu-alcohol dehydrogenase, specifically using NAD+ as cofactor, catalyzed the oxidation of aliphatic and aromatic alcohols with long chain alcohols being better substrates, indicating a barrel-shape hydrophobic binding pocket for substrate. mu-Alcohol dehydrogenase stood out in high Km values for both ethanol (18 mM) and NAD+ (340 microM) as well as in high Ki value (320 microM) for 4-methylpyrazole, a competitive inhibitor for ethanol. mu-Alcohol dehydrogenase may account for up to 50% of total stomach alcohol dehydrogenase activity and appeared to play a significant role in first-pass metabolism of ethanol in human.

[Interaction of human embryo cells derived from different tissues with lymphoblastoid cell lines]

Cells from skin and muscle of two month human embryo and from nasopharynx, tonsil, lung and kidney of four month human embryo were cocultivated with lymphoblastoid cells--B95-8 and Raji. It is found that all the epithelial cells, such as the focal growth of epithelioid cells from the tonsil and nasopharynx as well as kidney cells from the human embryo can not adhere to any kind of lymphoblastoid cells; but fibroblasts from muscle and skin of two month embryo or from nasopharynx, tonsil and lung of four month embryo have the ability of sticking to lymphoblastoid cells. However, only the fibroblastoid cells from the nasopharynx of human embryo have the ability to stick and to fuse with lymphoblastoid cells--B95-8 in cocultivation and to activate the EBV production. The mechanism of this phenomenon and its biological functions will be studied in detail.

Comparative effects of protein, protein hydrolysate and amino acid diets on nitrogen metabolism of normal, protein-deficient, gastrectomized or hepatectomized rats

The effects of diets containing protein, protein hydrolysate or an amino acid mixture on nitrogen metabolism of normal and severely protein-deficient rats and on rats after gastrectomy and hepatectomy were compared. In experiment 1, rats weighing about 80 g were fed one of three experimental diets containing casein, protein hydrolysate or an amino acid mixture for 28 d. In experiment 2, rats weighing about 270 g were fed a protein-free diet for 40 d, and then one of the above three experimental diets for 14 d. In experiment 3, rats weighing about 220 g were totally gastrectomized and fed one of the three experimental diets for 21 d. In experiment 4, rats weighing about 210 g had about 70% of the liver resected, and then were fed one of the three experimental diets for 15 d. In all four experiments, daily food intake, daily body weight gain, nitrogen balance, urinary nitrogen compounds, body composition and hematologic values were measured. In normal, protein-deficient and hepatectomized rats, most results were similar for the groups fed protein, protein hydrolysate or amino acid diets, except that urinary ammonia was higher in the group fed the amino acid diet than in the other two groups. For about 10 d after total gastrectomy, food intake and growth of the animals fed the protein diet were lower than in the other two groups.

Efficiency of utilization of soy protein isolate in Japanese young men

The nutritional quality of soy protein isolate (SPI) was evaluated in young men by the nitrogen balance method using fish protein as a standard. Twenty-one male university students were given SPI (Supro 620, Ralston Purina Co., St. Louis, Mo., U.S.A.), fish protein (cod fish) or a 50:50 mixture of the two proteins as the sole source of protein. SPI and fish were prepared as paste products (kamaboko). Four experimental periods were used in which each subject received 0.35, 0.45, 0.55 and 0.65 g protein/kg/day, respectively, given in random order. Each period consisted of one day on protein-free diet and ten days on the experimental diet, with an interval of three days on a free-choice (ad libitum) diet between periods. Energy intake was constant for each individual to maintain their body weight (44.6 +/- 2.4 kcal/kg/day). The linear regression equations obtained between nitrogen intake (X: mg N/kg/day) and the apparent nitrogen balance (Y: mg N/kg/day) were as follows: SPI, Y = 0.298X-35.2; fish protein, Y = 0.365X-31.8; mixed protein, Y = 0.423X-38.3. The nitrogen requirement for maintenance of nitrogen equilibrium determined from the regression equation was 118.1 +/- 15.4 mg N/kg/day for SPI, 87.1 +/- 17.2 mg N/kg/day for fish protein and 90.5 +/- 17.1 mg N/kg/day for mixed protein. The NPUs calculated at the respective maintenance nitrogen intakes were 38.9, 52.8 and 50.8 for SPI, fish protein and mixed protein, respectively. There was no significant difference between the nutritive values of mixed protein and fish protein. The nutritive value of SPI relative to fish protein was estimated as 82%, 74% and 74% by the slope-ratio method, and values for the nitrogen requirement and NPU, respectively.