alpha-Adducin gene and essential hypertension in China.

Adducin is a membrane skeletal protein that is involved in the regulation of membrane ion transport and cellular signal transduction. Essential hypertension has been linked to alpha-adducin gene locus, and association of a polymorphism of the gene has been found in some studies, but results of linkage or association studies on alpha-adducin gene are controversial among different populations. This study was designed to examine the linkage between alpha-adducin gene locus and essential hypertension and to reveal the relationship between an alpha-adducin gene polymorphism (Gly460Trp) and essential hypertension in a Chinese population. For the linkage study, one hundred and six Chinese nuclear families were recruited, including 417 hypertensive patients in all 474 individuals. Those samples were genotyped at D4S412 and D4S3038. The distances between the two microsatellite markers and the alpha-adducin gene locus are less than 3cM. Parametric, non-parametric linkage (NPL) analyses using the GENEHUNTER software were carried out. Sib transmission-dise- quilibrium test (S-TDT), as well as transmission-disequilibrium test (TDT). was also implemented with TDT/S-TDT Program 1.1. Serum levels of uric acid, creatinine, blood urea nitrogen (BUN), fasting glucose and lipids were determined as phenotypes. In an association study, 138 hypertensive and 121 normotensive subjects were genotyped at Gly460Trp of the alpha-adducin gene to examine a possible association between this polymorphism and blood pressure or other phenotypes. We fail to find the linkage between the two markers and essential hypertension by parametric, NPL analysis or TDT/S-TDT study. With the use of the simple association and the multivariate logistic regression analyses, we also fail to reveal a significant association between the Gly460Trp polymorphism in alpha-adducin gene and the blood pressure variation, or blood biochemical indices studied. The frequency of the 460Trp allele in Chinese (46-48%) is similar to that found in Japanese (54-60%) while the allele frequency is less common in Caucasian (13%-23%). These findings suggest that in our Chinese population, alpha-adducin 460Trp variant may not play an important role in the etiology of EH. And the negative results of linkage and TDT/ S-TDT further supports this conclusion.

Diagnosis of Liddle syndrome by genetic analysis of beta and gamma subunits of epithelial sodium channel--a report of five affected family members.

OBJECTIVE: To screen the gene mutation in beta and gamma subunits of the epithelial sodium channel (ENaC) of a Chinese family, some of whose members are clinically diagnosed as suffering from Liddle syndrome. METHODS: Twelve family members were recruited to the study. Among them, two brothers had been clinically diagnosed as suffering from Liddle syndrome. Peripheral blood samples were collected from all members of the family and total genomic DNA was prepared for genetic analysis. Polymerase chain reaction (PCR) was used for amplifying the last exon of beta (codon 513-673) and gamma (codon 503-632) subunits of the ENaC gene. PCR products were purified and subjected to a direct DNA sequence analysis. RESULTS: Genetic analysis of the beta ENaC gene revealed a missense mutation of CCC to CTC at codon 616 in four middle-aged men of the second generation and one young woman of the third generation. There was no mutation of the gamma ENaC gene in any of the individuals examined. CONCLUSION: Through direct DNA sequencing analysis, we diagnosed the disease present in five members of a Chinese family as Liddle syndrome, and excluded it in some other young offspring suffering from the monogenic disease. Our results provide further evidence that Pro616 is a critical amino acid that has a key role in the inhibition of sodium channel activity.

L-phenylalanine and smooth muscle cell proliferation from SHR and WKY rats.

Cell growth and proliferation were evaluated in cultured vascular smooth muscle cells (VSMCs) isolated from spontaneously hypertensive rat (SHR) and normotensive Wistar-Kyoto (WKY) rat aortae by measuring [3H]-thymidine incorporation into newly synthesized DNA and by determining cell number, respectively. The results showed that in cultures from both rat strains (1) serum-, basic fibroblast growth factor (bFGF)- and thrombin-induced DNA synthesis were inhibited by L-phenylalanine dose-dependently; (2) L-phenylalanine inhibited cell proliferation in response to serum in a concentration-dependent manner; (3) L-phenylalanine inhibited serum-induced proto-oncogene c-fos and c-myc expression; (4) L-tyrosine, L-histidine and D-phenylalanine failed to mimic the inhibitory effect of L-phenylalanine. All these data demonstrate that L-phenylalanine could exert a direct and specific antiproliferative effect on VSMCs suggesting that such effect can account for the antihypertensive action of this amino acid observed in SHR.

Reference data on the anatomy, hematology and biochemistry of 9-month-old silver foxes.

Anthropometric, anatomical, hematological and biochemical reference values were estimated in clinically healthy male and female 9-month-old silver foxes. The coefficients of variation of anthropometric and anatomical measurements for 9-month-old silver foxes were as low as previously reported for adult foxes. However, in relation to body size, all measurements were smaller. Compared with adult silver foxes, higher values were observed in serum levels of triglyceride, phospholipid, beta-lipoprotein, blood urea nitrogen and total protein. Similarly, higher levels were obtained for serum enzymes, especially aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK). The high levels of these serum enzymes may be due to handling stress. Inorganic phosphorus and calcium concentrations in the young foxes were also high. The alkaline phosphatase (ALP) level, reflecting the level of bone growth, was higher than that of adults. Biochemical values of beta-lipoprotein glucose and calcium in male 9-month-old silver foxes were lower than those of females, whereas those of total cholesterol, total protein, fructosamine, iron, albumin and beta-globulin were higher.

Reference data on the anatomy and serum biochemistry of the silver fox.

Clinically healthy silver foxes obtained from a closed colony were investigated for the purpose of establishing base-line data for this species. The anthropometry (body weight; body length; length and width of the head; width, depth, and circumference of the chest; length of the tail), anatomical measurements (weight; longitudinal and transverse length; thickness of the main organs) and serum biochemical assays (AST, ALT, ALP, LDH, CK, lipase, GGT, T-Cho, beta-Lipo, TG, Phos-Lip, Tp, T-Bil, UA, BUN, Crea, Glu, Ca, IP, Mg, Fe, Na, K, Cl, LDH and CK isoenzymes) were carried out. The data were presented as mean values with standard deviations, and compared with those of the dog. The coefficient of variation (CV) for each of the anthropometric parameters was low, except for that of female body weight for which the CV was 17%. The body size of the male was larger than the female, and the weights of the main organs, corresponding to body size, were greater than the female. The results were equivalent to those for a Beagle dog aged between 3 and 5 months. Significant differences between the sexes were detected in the following parameters: concentrations of BUN, beta-Lipo and T-Bil (p less than 0.01); concentration of Mg and Glu (p less than 0.05); activity of LDH and lipase (p less than 0.05). The biochemical data ware uniform with some exceptions. These were AST (142 IU/l) and ALP (122 IU/l) in a 5-year-old male fox, Glu (over 200 mg/dl) in four 2-year-old female foxes, CK (629 IU/l) in a 2-year-old female fox, and finally CK (366 IU/l) and lipase (428 IU/l) in an 8-year-old female fox, all of which were elevated. These data were similar to the reference values for the dog previously reported. The reference values presented in this report for the silver fox will be valuable as a guide for clinical diagnosis and research.