The CAG repeats number of spinocerebellar ataxia type 1 gene in normal Taiwanese and in patients with dominant inherited ataxia

Spinocerebellar ataxia type 1 (SCA 1) is an autosomal dominant disorder characterized by neurodegeneration of the cerebellum, spinal cord and brainstem. This neurodegeneration disease is associated with expansion of unstable CAG repeats within the coding region of the gene. We are conducting a local survey of the normal population and candidate patients to analyze the CAG repeats in SCA 1 gene. So far, we have collected peripheral blood from 78 normal individuals and 10 patients with dominant inherited ataxia disorders, and assayed the SCA1 CAG trinucleotide repeat using genomic polymerase chain reaction (PCR). Even though no local SCA 1 patients have been identified, we have established the distributions of the CAG repeat units of SCA 1 gene in the normal population in Taiwan. The normal range of CAG repeats is from 22 to 33 repeats, with the most common being 30 repeats. The range is relatively narrow compared to that reported for other ethnic groups. In addition, direct genomic PCR analysis of the SCA 1 gene from villous DNA has been successful in our laboratory. Screening of SCA 1 patients from patients with dominant inherited ataxia is currently underway in our laboratory. Here, we demonstrate that our molecular analysis technique makes possible the quick and accurate diagnosis of SCA1 patients and prenatal screening for SCA 1 families.

Self-assembly of the JC virus major capsid protein, VP1, expressed in insect cells

The major capsid protein of human polyomavirus JC virus, VP1, has been cloned into a baculovirus genome and expressed in insect cells. The VP1 protein was expressed in the cytoplasm and transported into the nucleus. It was then purified by a sucrose cushion and CsCI density gradient centrifugation to near homogeneity. Electron microscopy showed that isolated recombinant VP1 protein self-assembled into a capsid-like structure similar to the natural empty capsid. Both chelator (EDTA) and reducing agent (DTT) are required to disrupt the capsid structure into the pentameric capsomeres, as demonstrated by haemagglutination assay and electron microscopy. These results suggest that JC virus VP1 can be transported into the nucleus and self-assembled to form capsid-like particles without the involvement of the viral minor capsid proteins, VP2 and VP3. In addition, metal ions and disulphide bonds appear to be important in maintaining the integrity of the viral capsid structure.

Spontaneous and induced sister chromatid exchanges and delayed cell proliferation in peripheral lymphocytes of Bowen's disease patients and matched controls of arseniasis-hyperendemic villages in Taiwan

A total of 15 newly-developed Bowen's disease patients and 34 age-sex-residence-matched controls were recruited from three arseniasis-hyperendemic villages in Taiwan to compare spontaneous and arsenic-induced sister chromatid exchanges (SCEs), proportion of cells with high frequencies of SCEs (HFCs), and replication index (RI) in their peripheral lymphocytes. Arsenic-induced Bowen's disease patients were found to have significantly higher spontaneous SCEs and HFCs and a lower spontaneous RI than in matched controls without or with adjustment for age, gender, cigarette smoking, alcohol drinking, tea drinking, status of major diseases, HBsAg carrier status and arsenic exposure indices through multivariate analysis. Sodium arsenite was found to increase SCEs and HFCs and to decrease RI in a dose-response pattern for both cases and controls. The arsenic-induced decrease in RI was significantly greater in arsenic-induced Bowen's disease patients than in matched controls. The arsenic-induced increases in SCEs and HFCs were also consistently, but not statistically significantly, higher in arsenic-induced Bowen's disease patients than in matched controls at all arsenite treatment levels of 0.5, 1.0 and 2.0 microM. The arsenic-induced increase in cytogenetic damages and decrease in cell proliferation among arsenic-induced Bowen's disease patients compared with matched controls may result from their long-term exposure to inorganic arsenic through consumption of high-arsenic artesian well water, elevated individual genetic and acquired susceptibility to arsenic-induced damage, or both.

[A comparison between the results of cancer mortalities in 1972-1975 and in 1992-1994 in a rural area of Shanxi Province, China]

From Jan. 1995 to Jan. 1996, an investigation on the mortality of malignant tumours in three counties, Feng, Mei, Qishan, in Baoji area Shanxi Province during 1992-1994, had been carried out. Comparing the results of this study to the results from the cancer survey carried out in 1970' in China, we noticed that the average ages of death to breast cancer had decreased but deaths to lymphoma and leukemia had increased dramatically. Sex ratios (male/female) of nasopharyngeal carcinoma and brain tumor had also increased dramatically. However, crude mortalities and age standardized mortalities decreased with esophageal cancer the most in all types of cancers except cancer of the lung. Comparing the ranking of cancer death rates with that of the 1970's, liver cancer upgraded from the 3rd place to the 1st, but esophageal cancer descended from the 1st to the 4th place. Cancers topped the first 5 places were: liver, stomach, lung, esophagus and colon. The proportion of deaths from cancers of the digestive system cancers including liver, stomach, esophagus, gallbladder and pancreas was 64.27%. Death due to cancers from digestive system was the main part of all deaths caused by all types of cancers in this area.

Inhibitors of serine/threonine-specific protein phosphatases stimulate transcription by the Ah receptor/Arnt dimer by affecting a step subsequent to XRE binding

The Ah receptor binds aryl hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with high affinity. After binding aryl hydrocarbons, the receptor releases the 90-kDa heat shock protein and forms a dimer with the Arnt protein capable of binding at xenobiotic-responsive elements (XREs) and stimulating the transcription of genes involved in the metabolism of aryl hydrocarbons. The activity of the Ah receptor/ Arnt dimer can be decreased by treatments causing the down-regulation of protein kinase C and decreasing the nuclear accumulation of the receptor. Incubation with acid phosphatase or with alkaline phosphatase has been reported to block XRE binding. Thus the literature suggests that phosphorylation regulates Ah receptor activity by affecting DNA binding and/or nuclear transport. A reporter plasmid containing two XREs was used to investigate the effects of phosphatase inhibitors on TCDD-dependent transcription by the Hepa-1 mouse liver cell line. The inhibitors calyculin A and okadaic acid caused two- to threefold increases in TCDD-dependent transcription at concentrations capable of selectively inhibiting protein phosphatase 1 and protein phosphatase 2A. The inhibitor cyclosporin A doubled TCDD-dependent transcription at a concentration capable of selectively inhibiting protein phosphatase 2B. All three of the phosphatase inhibitors increased TCDD-dependent transcription without affecting transcription in the absence of TCDD. Nuclear extracts were prepared from cells treated with concentrations of okadaic acid or cyclosporin A which substantially stimulated TCDD-dependent transcription. Neither of the inhibitors significantly increased the level of TCDD-dependent XRE binding in the extracts. GAL4-Arnt fusion proteins were used to further investigate whether the phosphatase inhibitors affected a step other than DNA binding. Okadaic acid treatment specifically increased the ability of a GAL4 fusion protein containing the Arnt PAS and transactivation domains to stimulate transcription. These results suggest that serine/threonine-specific protein phosphatases can act at a level subsequent to XRE binding to inhibit the ability of the Ah receptor/Arnt dimer to stimulate transcription.

Familial transmission of the FMR1 CGG repeat

To better define the nature of FMR1 CGG-repeat expansions, changes in allele sizes for 191 families with fragile X and for 33 families with gray-zone repeats (40-60) were analyzed. Expansion of the fragile X chromosome to the full mutation was seen in 13.4% of offspring from premutation mothers with 56-59 repeats, 20.6% of those with 60-69 repeats, 57.8% of those with 70-79 repeats, 72.9% of those with 80-89 repeats, and 97.3% of those with 90-199 repeats. For premutation fathers, the majority (62%) of their daughters had a larger repeat number, while a few had either a smaller (22%) or the same (16%) repeat number, compared with their fathers' sizes. However, daughters with a smaller repeat number were observed only if their fathers had > or = 80 repeats. Fifteen (39.5%) of 38 such daughters carried a smaller repeat than did their fathers. We observed that a similar repeat number was inherited more often than expected by chance, among the members of a sibship segregating fragile X. This familial clustering, observed in the offspring of both males and females with a premutation, implies there may be an additional factor, independent of parental repeat size, that influences CGG-repeat instability. Instability in gray-zone allele transmissions was observed in 25% of alleles with 50-60 CGGs but in <8% of those with 40-49 CGGs. Examination of gray-zone allele organization revealed that long tracts of pure CGGs (>34) are not always unstably transmitted. These results raise new questions regarding the familial factors that may determine transmission expansions.

[Radioepidemiological studies in the nuclear industry of China]

The results of retrospective-cohort radioepidemiological studies on workers of mines and plants governed by China National Nuclear Corporation was reported. The total number was 40,122 persons and 575,411 person-years. The accumulated personal dose in workers of reactor, nuclear fuel reprocessing plants and research units was 57 mSv on the average. For fuel element fabrication and diffusion plants, it was about 5 mSv. Mortality of cancers, especially the non-cancerous diseases was not higher but lower than the controlled group and national values, showing the so-called health worker effect. 31,786 off springs of workers in the nuclear plants were examined. There were no significant difference in the incidence of hereditary-congenital diseases among exposed and controlled groups. The results mentioned above provide the direct medical evidences of the safety of nuclear industry in China. Owing to the high concentration of radon in the uranium prospective and mining tunnels in early years, the average cumulative exposure to radon progeny was about 80 WLM for miners who had the history of working underground. The relative risk of lung cancer was about 2. The excess relative risk per WLM was similar to the value reported abroad.

Large-scale Vero cell culture on microcarriers in a twenty-liter stirred tank fermentor

In biotechnology, animal cell culture is an important process for the production of many biologicals such as vaccines, monoclonal antibodies, or other recombinant products. Among many established continuous cell lines, Vero cells can be maintained in many passages in cultures without inducing tumorigenicity and have been recommended by World Health Organization for the production of human biologicals. Owing to its anchorage-dependent growth characteristics, Vero cells can be grown on microcarrier in a suspension vessel where microcarrier provides the culture system with a high culture surface to volume ratio. In this paper we compared the growth kinetics of Vero cells on Cytodex 1 microcarrier in a 20-liter fermentor vs. 100 ml spinner flask culture. The kinetics of Vero cell growth in the 20-liter fermentor was similar to the results obtained from small spinner flask culture, as determined by cell specific growth rate or corresponding doubling time. The approximately 150-fold increase in culture vessel volume did not compromise the growth kinetics of Vero cells, suggesting the system is applicable for large stirred-tank fermentor cultures.

Prenatal diagnosis and carrier screening for fragile X by PCR

During the past three years, we have conducted fragile X DNA studies for carrier screening and prenatal diagnosis using a previously described PCR protocol that accurately resolves normal FMR1 alleles and premutations and detects most full mutations [Brown et al., JAMA 270:1569-1575, 1996]. A total of 344 pregnant women with a family history of mental retardation of unknown cause were screened and 6 fragile X carriers were identified: two had full mutations, and four had premutations. The mentally retarded relatives of two other women were found to be fragile X positive although the women themselves were not carriers. In all, 6 carriers and 8 fragile X families were identified by this screening. We have also screened 40 pregnant women who were members of previously identified fragile X families, but whose carrier status was unknown. Ten were found to be carriers and were offered prenatal diagnosis. Prospective prenatal testing of 84 carrier women correctly detected 31 fetal samples (19 females, 12 males) with full mutations and 6 with premutations (2 females, 4 males). No false positives but one false negative occurred early on due to undetected maternal cell contamination. In addition, screening of 806 males with developmental delays of unknown cause gave positive results in 33 (4.1%). Potential problems and pitfalls of direct DNA testing are discussed. Because of the proven success of fragile X screening with direct molecular analysis, screening of all undiagnosed individuals with mental retardation and at risk pregnant women should now be considered. The identification of fragile X carriers and prenatal diagnosis of their pregnancies should significantly reduce the prevalence of this syndrome.

A novel secondary metabolite relative to the degradation of PR toxin by Penicillium roqueforti

A secondary metabolite different from PR-imine and PR-amide was produced in the liquid (YESC) and solid (buckwheat) culture medium of Penicillium roqueforti. We isolated and purified the compound in pure and colorless crystalline form. On the basis of elemental analysis, mass, 1H and 13C nuclear magnetic resonance, infrared, and UV spectroscopy, the compound was identified as PR-acid (C17H20O7). The structures of PR-acid and PR toxin (C17H20O6) are closely related. Moreover, we discovered that PR-acid disappeared concurrently with the PR toxin in the culture medium. Thus, we postulate that PR toxin is degraded to PR-acid in the culture of P. roqueforti.

Comparative plasma and tissue pharmacokinetics and drug residue profiles of different chemotherapeutants in fowls and rabbits

Blood and tissue pharmacokinetics and drug residue profiles of six chemotherapeutants were studied. Ceftriaxone (CEF), intravenously at 50 mg/kg, sulfamonomethoxine (SMM) and sulfaquinoxaline (SQ), orally at 200 mg/kg, and olaquindox (OLA), orally at 50 mg/kg, were administered to young broilers. Penicillin (PEN), intramuscularly at 200,000 U/kg, and albendazole (ALB), orally at 20 mg/kg, were given to rabbits. For each drug, 13-18 groups (n = 5-10 individuals/group) of the dosed animals were killed at different post-dosing times. Drug and/or metabolite concentrations in plasma, liver, kidney, heart, lung, and muscle tissues were analysed by HPLC procedures. Multi-exponential kinetic models were fitted to the observed tissue concentration-time data by applying a non-linear least-squares regression computer program. Tissue half-life, peak tissue concentration, and time of peak tissue concentration were determined. Half-life of CEF, SMM, SQ, OLA, PEN, ALB, and two metabolites of ALB (sulfoxide and sulfone) in various tissues ranged 0.6-1.4, 4.7-9.0, 4.5-18.9, 1.8-3.1, 0.9-3.0, 3.4-9.6, 5.0-16.1 and 7.4-12.2 h. The times required for CEF, SMM, SQ, OLA, PEN, and ALB residue concentrations to decline to 0.1 microgram/g in various tissues ranged from 5.0-11.6, 70.0-110.5, 114.0-179.8, 21.3-30.3, 4.1-24.8 and 47.8-84.4 h. Drug kinetic characteristics in tissues differed significantly from those in plasma, and also varied from tissue to tissue. It is necessary, therefore, to evaluate tissue kinetics when designing dosage regimens in tissue infection chemotherapy with these drugs. Knowledge of tissue kinetics is also important in predicting and controlling drug residues in edible tissues of food-producing animals.

Superior extension of the parascapular free flap for cervical burn scar contracture

A newly designed superior extension of the parascapular free flap and its free transfer clinically for the repair of 11 cases of cervical burn scar contracture without any loss are presented. The flap sizes ranged from 16 x 7 cm to 32 x 11 cm. Based on the anatomic distribution of the circumflex scapular vessels, the flap in the scapular territory can be taken much longer and wider than before. There is less tension in this vertically oriented flap than in the horizontally oriented flap in obtaining primary closure. This method extends the application of the scapular territory as a donor site for free flaps.

The DNA binding of purified Ah receptor heterodimer is regulated by redox conditions

The Ah receptor from rat liver has been purified, using a specific oligonucleotide affinity column, in order to characterize the components of the receptor and to investigate features that modulate its DNA-binding activity. The purified DNA-binding form of rat Ah receptor contains three major components, with estimated molecular masses of 108, 98, and 96 kDa. Antibodies to two peptides from the mouse Ah receptor bind the 108-kDa protein, but not the 98-kDa protein, and bind weakly at the position of the 96-kDa protein. The sequences of four peptides from samples containing both the 96- and 98-kDa proteins are all highly similar to segments of the human Ah receptor nuclear translocator (Arnt) protein. Antibodies to a peptide from the human Arnt protein bind the 96- and 98-kDa proteins, but not the 108-kDa protein. These data show that the Ah receptor itself and two forms of the Arnt protein are the major components of the purified DNA-binding form of receptor. In gel shift assays the purified receptor forms two specifically bound complexes with a xenobiotic responsive element (XRE), which may correspond to Ah receptor heterodimers with either of the two forms of Arnt protein. The DNA binding of the purified heterodimer is substantially decreased under oxidizing conditions. Oxidation inhibits receptor DNA binding without greatly altering the size of the purified heterodimer. This sediments at 5.9S in its reduced form and at 6.5S in its oxidized form. Dithiothreitol restores the XRE binding of oxidized receptor, with similar effects on both of the receptor-XRE complexes. In the presence of nuclear extract, reduced thioredoxin also restores the XRE binding of oxidized receptor.

Optical method for measurement of number and shape of attached cells in real time

A novel, on-line method of accurately parametrizing the shape of spreading cells is described. The substrate on which the cells are deposited serves as an optical waveguide. The method is based on the interaction between the evanescent part of the guided waves and the cells. No special labelling of the cells is required. A mathematical framework for interpreting the results is derived, and some illustrative results are presented.

Adenosine deaminase inhibitors. Synthesis and biological evaluation of putative metabolites of (+)-erythro-9-(2S-hydroxy-3R-nonyl)adenine

The synthesis and biological evaluation of three chain-hydroxylated (+)-erythro-9-(2S-hydroxy-3R-nonyl)adenine [(+)-EHNA] derivatives are reported. Hydroxy groups at positions 9', 8', and 8',9' (12, 25, and 16) were introduced by either epoxidation or hydroboration of a terminal olefinic intermediate. Affinities for calf intestinal adenosine deaminase (ADA) were determined from the steady-state inhibition of adenosine deamination. Ki values of 0.82, 3.8, 6.4, and 15.8 nM were estimated for (+)-EHNA, 9'-hydroxy-(+)-EHNA (12), 8'-hydroxy-(+)-EHNA (25), and 8',9'-dihydroxy-(+)-EHNA (16), respectively, by assuming a single class of binding sites. However, the data for all inhibitors conformed more closely to the kinetics of a heterogeneous system with different affinities for two or more binding sites. The fairly high potencies of 12 and 25 suggest that other substitutions at the terminal position of the nonyl chain could yield useful ADA inhibitors.

Measurement of adhesion and spreading kinetics of baby hamster kidney and hybridoma cells using an integrated optical method

A novel optical method was used for quantitative characterization and continuous measurement of both the adhesion and spreading of mammalian cells on inorganic surfaces. It is based upon the effective refractive index change caused by cells when they adhere to a planar optical waveguide. We have applied this technique to measure the kinetics of the adhesion and spreading processes of baby hamster kidney (BHK) cells adhering to surfaces coated with fibronectin and under different culture conditions (PBS, medium, serum, EDTA). In comparison, hybridoma cells are only adsorbed to the surface and do not spread at all. Moreover, this technique also allows the mass of an adsorbed protein adlayer to be determined very precisely and thus provides a valuable tool for screening suitable substrata as well as determining the influence of different culture conditions on cell adhesion and spreading. This sensitive test for substrate influence could be important in toxicity tests using adherent animal cells.

Inhibitory effect of 5 beta-pregnan-3 alpha-o1-20-one on gonadotropin-releasing hormone gene expression in the male rat

Neuroanatomical data have documented the existence of synaptic contacts between gamma-aminobutyric acid (GABA) terminals and preoptic gonadotropin-releasing hormone (GnRH) neurons in the rat anterior hypothalamus. In addition, pharmacological studies have suggested that the GABAergic system may be involved in the control of gonadotropin release. Moreover, it has been shown that some progesterone metabolites such as 5 beta-pregnan-3 alpha-ol-20-one (5 beta 3 alpha P) are able to interact with the GABAA receptor complex. In the present study, we have investigated the effects of chronic (5 days) treatment with the GABAA-positive ligand 5 beta 3 alpha P (20 mg/kg body weight i.p., twice a day) or with the GABAA agonist muscimol (1 mg/kg body weight i.p., twice a day) alone or in combination on GnRH mRNA levels in the preoptic area of the male anterior hypothalamus as measured by in situ hybridization. Treatment with 5 beta 3 alpha P produced a 30% decrease in the number of grains overlying labelled cells, while muscimol treatment decreased the hybridization signal by 36%. The concomitant administration of 5 beta 3 alpha P and muscimol resulted in a 46% decrease in the GnRH mRNA levels. This inhibitory effect was completely antagonized by the concomitant administration of picrotoxin (4 mg/kg body weight i.p., twice a day). These data suggest that the GABAA receptor complex and steroids that interact positively with this GABAA receptor complex may play an important role in the regulation of GnRH biosynthesis by hypothalamic neurons.

Fragile X induction systems in CVS cultures: effect on cytogenetic, PCR, and genomic Southern Blot DNA analyses of the FMR-1 gene

Low fragile X frequencies have been commonly observed in chorionic villus sample (CVS) cultures, compared to subsequent analysis in whole blood or products of conception (POC). To investigate possible mechanisms for this effect, CVS cultures from a previously identified fragile X positive male, were restudied and compared to subsequent POC cultures from lung, muscle, skin, and thymus. Cultures were exposed, for the last 24 hours before harvesting, to FUdR, excess thymidine, and a combination of both. For CVS, only those cultures that were exposed to a combination of FUdR and excess thymidine showed positive cytogenetic findings (1/90 or 1.1%), agreeing with our original positive cytogenetic results (2/86 or 2.3%) for cultures exposed to excess thymidine. Fragile X frequencies in the POC tissues from this fetus increased to an average of 14%. PCR analyses showed full mutations (> 200 CGG repeats) in uninduced CVS cultures but induced cultures exhibited apparently smaller sizes in the range of 120-180 repeats. The results showed variability. In one instance, the banding pattern from one of the uninduced cultures was similar to the results where cultures were exposed to a double induction system. When PCR analyses were conducted on induced POC cultures, full mutations were observed in virtually all samples. Southern blot genomic analysis using probe StB12.3 showed an unmethylated full mutation in CVS cultures. Southern blot patterns from cultures of muscle revealed size variations of DNA bands in the premutation range representing unmethylated DNA as well as methylated full mutations. Finally, variations were also observed in lung and skin cultures, compared to CVS and muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Sequential cytogenetic alterations in hamster oral keratinocytes during DMBA-induced oral carcinogenesis

Using the hamster cheek pouch oral cancer model, we have performed a comprehensive analysis of the cytogenetic changes in hamster oral keratinocytes during 7,12-dimethylbenz[a]anthracene (DMBA)-induced carcinogenesis. Tumour induction in the hamster cheek pouch required repeated application of the carcinogen for 14 weeks. We have found that this hamster oral cancer model to be suitable for cytogenetic studies. Unlike human oral cancers where chromosome breaks have been shown, this is only infrequently observed in DMBA-treated hamster oral keratinocytes. Of importance is the finding that at the beginning of the second week of DMBA treatment, there is a significant increase of karyotypes demonstrating tetraploid or near-tetraploidy. We propose that the significant increase in hamster oral keratinocytes exhibiting tetraploidy be further evaluated as a marker of premalignancy/malignancy.

The relationship between PGE2 level in mothers' milk and physiological diarrhea of the baby and the treatment

Physiological diarrhea of baby during the period of breastfeeding often occurs. To investigate the relationship between mother's milk and the physiological diarrhea of baby, we measured the PGE2 levels in milk of 320 lactating women within 4 months of postpartum with radioimmunoassay and the mean value of PGE2 level was 216.8 +/- 145.2 ng/L. The PGE2 levels in mother's milk in the group with diarrhea were 286.5 +/- 142.2 ng/L, that of control group 130.4 +/- 76.3 ng/L. The difference was obviously significant (P < 0.001). The physiological diarrhea of baby was positively related to the PGE2 level in mother's milk (r = 0.75, P < 0.01) i.e., the high PGE2 level in mother's milk may be an important cause of diseases. The observation on 102 cases of baby with severe physiological diarrhea showed a higher level of PGE2 in the mother's milk. 52 cases of lactating women in the treated group were given indomethacin, and after treatment the PGE2 level in mother's milk decreased obviously, and the diarrhea of baby disappeared. The effective rate was 96.15%. No side effects were found in both mother and baby.