Decline of neural tube defects cases after a folic acid campaign in Nuevo León,México

BACKGROUND: Nuevo León is a state in northeastern Mexico, near the border of Texas. Mean mortality rate from 1996-98 due to anencephaly cases was 0.6/1,000. In 1999 a surveillance program for the registry and prevention of neural tube defects (NTD) cases was initiated. METHODS: Cases were obtained from hospitals and OB-GYN clinics by immediate notification, death certificates, or fetal death registries. Only isolated cases of NTD were included. In August 1999 a folic acid campaign was initiated with the free distribution of the vitamin to low-income women with a recommendation to take a 5.0-mg pill once a week. Number of cases and rates from 1999 to 2001 were compared (chi(2) test). RESULTS: After 2 years there has been a significant reduction in the number of cases and rates. In 1999 there were 95 NTD cases and in the years 2000 and 2001 there were only 59 and 55 respectively (P < 0.001). NTD rate decreased from 1.04/1,000 in 1999 to 0.58/1,000 in 2001. Anencephaly and spina bifida rates decreased from 0.55/1,000 to 0.29/1,000 and from 0.47/1,000 to 0.22/1,000 respectively, from 1999-2001. Decrease of female cases was higher than male cases for both phenotypes. CONCLUSION: After 2 years there was a 50% decrease in the incidence of anencephaly and spina bifida cases with a significant reduction of infant mortality and disability. These results encourage us to propose the use of a single tablet of 5.0-mg of folic acid per week as an alternative to supplementation on a daily basis.     

Purification and characterization of an extracellular protease from Penicillium chrysogenum Pg222 active against meat proteins

An extracellular protease from Penicillium chrysogenum (Pg222) isolated from dry-cured ham has been purified. The purification procedure involved several steps: ammonium sulfate precipitation, ion-exchange chromatography, filtration, and separation by high-performance liquid chromatography. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and gel filtration, the purified fraction showed a molecular mass of about 35 kDa. The hydrolytic properties of the purified enzyme (EPg222) on extracted pork myofibrillar proteins under several conditions were evaluated by SDS-PAGE. EPg222 showed activity in the range of 10 to 60 degrees C in temperature, 0 to 3 M NaCl, and pH 5 to 7, with maximum activity at pH 6, 45 degrees C, and 0.25 M NaCl. Under these conditions the enzyme was most active against tropomyosin, actin, and myosin. EPg222 showed collagenolytic activity but did not hydrolyze myoglobin. EPg222 showed higher activity than other proteolytic enzymes like papain, trypsin, and Aspergillus oryzae protease. The N-terminal amino acid sequence was determined and was found to be Glu-Asn-Pro-Leu-Gln-Pro-Asn-Ala-Pro-Ser-Trp. This partial amino acid sequence revealed a 55% homology with serine proteases from Penicillium citrinum. The activity of this novel protease may be of interest in ripening and generating the flavor of dry-cured meat products.     

In vitro and in vivo anti-Trypanosoma cruzi activity of a novel nitro-derivative

Nitroarylidenemalononitriles and their cyanoacetamide derivatives with remarkable anti-epimastigote properties, were synthesized attempting to obtain new 3,5-diamino-4-(5'-nitroarylidene)-4H-thiadiazine 1,1-dioxide derivatives, which in previous reports had shown anti-Trypanosoma cruzi activity. Tests to evaluate the cytotoxicity of compounds were performed on J774 macrophages. 5-nitro-2-thienyl-malononitrile (5NO2TM), was the only product which maintained a high anti-epimastigote activity at concentrations in which it was no longer cytotoxic, thus it was assayed against intracellular amastigotes. Its anti-amastigote activity was similar to that of nifurtimox. Afterwards in vivo toxicity and anti-chagasic activity were determined. A reduction in parasitemia was observed.     

One-tube nested polymerase chain reaction for detection of Chlamydia trachomatis

Here we present a one-tube nested PCR test, which allows the detection of minimal quantities of Chlamydia trachomatis in human fluids. This assay includes the use of an internal control to avoid false negative results due to the presence of inhibitors. The results obtained show that this assay is robust enough to be used for clinical diagnosis.     

Paratuberculosis in free-ranging fallow deer in Spain

Paratuberculosis was diagnosed in a population of approximately 1,000 free-ranging fallow deer (Dama dama) sampled from 1997-98 in the Regional Hunting Reserve of El Sueve (Asturias, Spain). Five of eight animals observed with diarrhea were diagnosed as having paratuberculosis on the basis of gross lesions at postmortem examination and histopathology. In two deer, Mycobacterium avium subsp. paratuberculosis was cultured and identified by polymerase chain reaction. Indirect enzyme-linked immunosorbent assay and immunodiffusion tests were used to evaluate sera from 33 adult deer from this population. All fallow deer tested were seronegative.     

Characterization of two highly similar Rad51 homologs of Physcomitrella patens

The moss Physcomitrella patens, which is a land plant with efficient homologous recombination, encodes two Rad51 proteins (PpaRad51.1 and PpaRad51.2). The PpaRad51.1 and PpaRad51.2 proteins, which share 94 % identity between them, interact with themselves and with each other. Both proteins bind ssDNA and dsDNA in a Mg(2+) and pH-dependent manner, with a stoichiometry of one PpaRad51.1 monomer per 3(+/-1) nt or bp and one PpaRad51.2 monomer per 1(+/-0.5) nt or bp, respectively. At neutral pH, a 1.6-fold excess of both proteins is required for ssDNA and dsDNA binding. PpaRad51.1 and PpaRad51.2 show ssDNA-dependent ATPase activity and efficiently promote strand annealing in a nucleotide-independent but in a Mg(2+)-dependent manner. Both proteins promote joint-molecule formation, DNA strand invasion and are able to catalyse strand exchange in the presence of Mg(2+) and ATP. No further increase in the activities is observed when both proteins are present in the same reaction. None of the PpaRad51 gene products complement the DNA repair and recombination phenotype of Saccharomyces cerevisiae rad51delta mutants. However, PpaRad51.1 confers a dominant-negative DNA repair phenotype, and both PpaRad51 proteins reduce the levels of double-strand break-induced recombination when overexpressed in S. cerevisiae wt cells. These results suggest that both PpaRad51 proteins are bona fide Rad51 proteins that may contribute, in a different manner, to homologous recombination, and that they might replace ScRad51 in a hypothetical yeast protein complex inactivating different functions required for recombinational repair.     

Subtype-specific regulation of the expression and function of muscarinic acetylcholine receptors in embryonic chicken retinal cells

We examined the effect of long-term agonist exposure on muscarinic acetylcholine receptor expression and function in embryonic chicken retinal cells. Long-term carbachol exposure induced a time- and concentration-dependent decrease in M2, M3 and M4 muscarinic receptor numbers. Kinetic analyses revealed a first-order process with similar rate constants for all three subtypes. Both the maximal decrease and the agonist potency for regulation of M3 were significantly higher than those for M2 and M4. Upon agonist removal, M2 and M4 numbers returned to control values, but M3 recovery after 24 h was no higher than 40%. Agonist treatment did not alter the levels of receptor mRNAs. Receptor inactivation with a covalent alkylating antagonist demonstrated that the partial M3 protein recovery was not due to a decreased intrinsic basal rate of synthesis, suggesting that it is induced by agonist treatment. Prolonged carbachol exposure induced concomitant decreases in muscarinic-mediated inhibition of cyclic AMP accumulation which were completely reversed after agonist removal. Sustained receptor activation also promoted significant decreases in muscarinic receptor-stimulated phosphoinositide turnover, which were only partially reversed after agonist removal. These data demonstrate subtype-specific regulation of the expression and function of muscarinic receptors in the retina.