Frequent spontaneous deletions at a shuttle vector locus in transgenic mice

Transgenic mice carrying multiple copies of a recoverable lambdaphage shuttle vector (     

Ultrastructural morphometry of capillary basement membrane thickness in normal and transgenic diabetic mice

Capillary basement membrane (CBM) thickening is an ultrastructural hallmark in diabetic patients and in animal models of diabetes. However, the wide variety of tissues sampled and diverse methods employed have made the interpretation of thickness data difficult. We showed previously that acellular glomerular BMs in OVE26 transgenic diabetic mice were thickened beyond normal age-related thickening, and in the current study we hypothesized that other microvascular BMs likewise would show increased widths relative to age-matched controls. Accordingly, a series of tissues, including skeletal and cardiac muscle, ocular retina and choriod, peripheral nerve, lung, pancreas, and renal glomerulus was collected from 300-350-day-old normal and transgenic mice. Transmission electron micrographs of cross sections through capillary walls were prepared, and CBM thickness (CBMT) was determined by the "orthogonal intercept" method. Morphometric analyses showed highly variable transgene-related BMT increases in the sampled tissues, with glomerular BM showing by far the greatest increase (+87%). Significant thickness increases were also seen in the retina, pulmonary alveolus, and thoracoabdominal diaphragm. BMT increases were not universal; however, most were modestly widened, and those that were thickest in controls generally showed the greatest increase. Although the pathogenesis of diabetes-related increases in CBM is poorly understood, data in the current study showed that in OVE26 transgenic mice increased BMT was a frequent concomitant of hyperglycemia. Accordingly, it seems likely that hyperglycemia-induced microvascular damage may be a contributing factor in diabetic BM disease, and that microvessel cellular and extracellular heterogeneity may limit the extent of CBM thickening in diverse tissues.     

Kinetic studies on the yeast Phaffia rhodozyma

The yeast Phaffia rhodozyma, a promising microbial producer of the carotenoid astaxanthin, was cultivated in batch and continuous processes in an agitated and aerated fermenter using an acid peat extract - based culture medium. For the accelerated growth phase, the mean specific growth rate and doubling time were found to be 0.038 h^?1, and 18.24 hours, respectively. The production of astaxanthin was found to be basically growth associated, the maximum concentrations of the pigment produced in batch culture and continuous cultivation being similar.     

Detection of mutations in the glycine decarboxylase gene in patients with nonketotic hyperglycinaemia

Nonketotic hyperglycinaemia (NKH) is an autosomal recessive disorder of glycine metabolism caused by a deficiency in the mitochondrial glycine cleavage enzyme. The majority of cases are caused by mutations in the P-protein, one of the four components of the glycine cleavage enzyme, also known as glycine decarboxylase (GLDC). Previous studies searching for causative mutations in NKH patients have only looked for a limited number of specific mutations or only screened part of the gene, and in many cases either no mutation or only one mutation was found, which is of limited use for prenatal diagnosis. In this study, we describe the screening of the entire GLDC gene in 3 NKH families by D-HPLC analysis of all 25 exons, identifying two point mutations and two large deletions (exon 8 and exons 2-15) using a combination of D-HPLC analysis, long range PCR, Southern blot and sequencing. For complete prenatal testing both mutations need to be identified, and we suggest that screening of the entire gene as well as deletional analysis should be considered in those subjects where only one mutation has been identified.     

Evaluating plasma holds in the presence of multiple infections

To protect plasma supplies, donors are screened for infectiousdiseases. As an added measure of protection, donations are identifiedand stored for a period of time to allow future discard in theevent that an identified donor subsequently tests positive forsome screened disease. Previous models for evaluating such plasmaholds have only addressed the case of a single infectious disease.This paper extends the analysis to the case of multiple infections.Given knowledge of the marginal incidence rates for those infectionschecked, upper and lower bounds for important quantities suchas the probability of interdicting an infectious but undetecteddonation, the expected number of infections interdicted perdonation, and the net economic benefits of the holding policyare developed. Several examples are developed, illustratinghow the models can be used to evaluate the consequences of aplasma hold.     

Comparative analysis of the NS 1 gene sequences of dengue-1 viruses prototype Hawaii strain and Thai isolate TH-Sman,and determination of the intratypic variation of NS 1 protein among dengue-1 viruses

Summary In view of a previous report on significant antigenic and biophysical differences between the purified soluble complement-fixing antigens of dengue-1 virus strains Hawaii and TH-Sman, the NS 1 genes of both virus isolates were cloned, sequenced, and compared in an attempt to define the genetic basis for the observed differences. Sequence comparison revealed ten encoded amino acid differences between the NS 1 genes of both viruses. Three of these amino acid differences, which are associated with a change in charge distribution, are clustered within the major antigenic region previously defined by studies of recombinant dengue-1 NS 1 protein expressed inE. coli. In parallel, the NS 1 sequences of both Hawaii and TH-Sman isolates were also aligned and compared with two other published dengue-1 NS 1 protein sequences to determine the intratypic variation of dengue-1 NS 1 antigen. Pairwise comparisons between the encoded amino acid sequences revealed a variability of 1.1% to 3.1% difference in the NS 1 protein among dengue-1 strains, which is comparable to that reported for dengue-1 envelope protein (0.2% to 3.6% difference) but less than that of dengue-2 NS 1 protein (0.6% to 7.4% difference).     

Regeneration of tooth development in vitro following sodium fluoride treatment

Mandibular incisors were dissected from the jaws of 15- and 16- days C57BL/10 mouse embryos and cultured on agar-solidified Eagle's basal medium supplemented with fetal calf serum, an antibiotic, and glutamine. The experimental medium was the same as the control except that fluoride was added such that the final concentrations ranged from 2.0-8.0 mM NaF. Control and experimental explants were recovered after two, four and six days of incubation and studied histologically. After two days of fluoride treatment (3.0 mM NaF), cellular degeneration was observed in the dental papilla mesenchyme while the enamel organ epithelium appeared more resistant. Prolonged treatment or treatment at higher concentrations resulted in destruction of the dental papilla. The enamel organ was still present but was abnormal and reduced. Older tooth germs were less affected overall when incubated at the same fluoride dosage and time of treatment. When explants subjected to limited exposure (2 days) to fluoride were placed on control medium, the suppressed tooth germs recovered. The recovery was enhanced by grafting untreated mesenchyme to the treated explants followed by incubation on control medium. The observations indicate that NaF can suppress the development of tooth germs in vitro and that recovery from the suppresion does occur. The more severe inhibition observed in the mesenchymal component when compared to the response of the epithelial component of the treated explants suggests that fluoride may alter the ultimate morphology of the tooth crown by disrupting the normal epithelial-mesenchymal interaction which occurs during early tooth development.     

Decomposing delta, theta, and alpha time-frequency ERP activity from a visual oddball task using PCA.

OBJECTIVE: Time-frequency (TF) analysis has become an important tool for assessing electrical and magnetic brain activity from event-related paradigms. In electrical potential data, theta and delta activities have been shown to underlie P300 activity, and alpha has been shown to be inhibited during P300 activity. Measures of delta, theta, and alpha activity are commonly taken from TF surfaces. However, methods for extracting relevant activity do not commonly go beyond taking means of windows on the surface, analogous to measuring activity within a defined P300 window in time-only signal representations. The current objective was to use a data driven method to derive relevant TF components from event-related potential data from a large number of participants in an oddball paradigm. METHODS: A recently developed PCA approach was employed to extract TF components [Bernat, E. M., Williams, W. J., and Gehring, W. J. (2005). Decomposing ERP time-frequency energy using PCA. Clin Neurophysiol, 116(6), 1314-1334] from an ERP dataset of 2068 17 year olds (979 males). TF activity was taken from both individual trials and condition averages. Activity including frequencies ranging from 0 to 14 Hz and time ranging from stimulus onset to 1312.5 ms were decomposed. RESULTS: A coordinated set of time-frequency events was apparent across the decompositions. Similar TF components representing earlier theta followed by delta were extracted from both individual trials and averaged data. Alpha activity, as predicted, was apparent only when time-frequency surfaces were generated from trial level data, and was characterized by a reduction during the P300. CONCLUSIONS: Theta, delta, and alpha activities were extracted with predictable time-courses. Notably, this approach was effective at characterizing data from a single-electrode. Finally, decomposition of TF data generated from individual trials and condition averages produced similar results, but with predictable differences. Specifically, trial level data evidenced more and more varied theta measures, and accounted for less overall variance.