Thyroid functions and serum lipids in older women: a population-based study

A new allelic series at the underwhite gene is described. Three of the alleles in the series--uw, uwd, and Uwdbr--arose as spontaneous mutations on different genetic backgrounds at The Jackson Laboratory. We report here the visible phenotypes and dominance hierarchy of these alleles, all of which are defined by a reduction of pigmentation in both eye and coat color. Electron microscopic analysis of retinal epithelium suggests that the primary defect is in the melanosome. The degree of severity of melanosome anomalies in the retina correlates with the degree of hypopigmentation in the coat. The perturbed gene and its gene product are unknown. We show that the uw locus is genetically distinct from Myo10, a suggested candidate gene for this mutation.     

Molecular, serological, and clinical features of 16 consecutive cases of invasive streptococcal disease. Southeastern Minnesota Streptococcal Working Group

We performed a comprehensive analysis of the molecular, serological, and clinical features of 16 consecutive cases of invasive streptococcal disease (ISD). The majority of cases were linked to two group A streptococcus (GAS) clones closely related by pulsed-field gel electrophoresis (PFGE) and designated as PFGE-1 and PFGE-1.1. These clones, serotyped as M-3, T-3/B3264, carried an allelic variant of the gene that encodes pyrogenic exotoxin A (speA3) and the gene that encodes streptococcal superantigen (SSA) but different emm alleles that encode M-protein. The characteristics and clinical features of patients were similar to those described in previous reports, regardless of the responsible GAS clone. However, worse clinical outcomes (shock and death) were more frequent when patients infected with PFGE1/1.1 clones were considered as a group and compared with all other patients as a group. One striking feature in some patients with deep tissue infection was a lack of inflammatory cells despite the presence of numerous streptococci. An evaluation of PFGE profiles of GAS isolated elsewhere demonstrated that the PFGE-1 clone has caused invasive disease in other locations in the United States and in Japan.     

Substitution of L-fucose by L-galactose in cell walls of Arabidopsis mur1

An Arabidopsis thaliana mutant (mur1) has less than 2 percent of the normal amounts of L-fucose in the primary cell walls of aerial portions of the plant. The survival of mur1 plants challenged the hypothesis that fucose is a required component of biologically active oligosaccharides derived from cell wall xyloglucan. However, the replacement of L-fucose (that is, 6-deoxy-L-galactose) by L-galactose does not detectably alter the biological activity of the oligosaccharides derived from xyloglucan. Thus, essential structural and conformational features of xyloglucan and xyloglucan-derived oligosaccharides are retained when L-galactose replaces L-fucose.     

The sevenfold way of PKC regulation

Protein kinase C (PKC) is a family of enzymes that are physiologically activated by 1,2-diacylglycerol (DAG) and other lipids. To date, 11 different isozymes, alpha, betaI, betaII, gamma, delta, epsilon, nu, lambda(iota), mu, theta and zeta, have been identified. On the basis of their structure and activators, they can be divided into three groups, two of which are activated by DAG or its surrogate, phorbol 12-myristate 13-acetate (PMA). PKC isozymes are remarkably different in number and prevalence in different cell lines and tissues. When activated, the isozymes bind to membrane phospholipids or to receptors that are located in and anchor the enzymes in a subcellular compartment. Some PKCs may also be activated in their soluble form. These enzymes phosphorylate serine and threonine residues on protein substrates, perhaps the best known of which are the myristoylated, alanine-rich C kinase substrate and nuclear lamins A, B and C. The enzymes clearly play a role in signal transduction, and, because of the importance of PMA as a tumor promoter, they are thought to affect some aspect of cell cycling. How PKC takes part in the regulation of cell transformation, growth, differentiation, ruffling, vesicle trafficking and gene expression, however, is largely unknown.     

Feeding diets containing high levels of milk products or cellulose decrease urease activity and ammonia production in rat intestine

Three studies were done to determine the effect of feeding diets containing high levels of a readily fermentable carbohydrate (lactose in milk or yogurt, or pure lactose) or an undigestible, unfermentable diluent (alpha-cellulose) on urease (EC 3.5.1.5) activity and net ammonia production in the rat gastrointestinal (GI) contents. Rats (170-200 g) were fed a control diet or diets containing 55% dried milk or 55% dried yogurt, 25% lactose or 10% alpha-cellulose. Feeding diets containing milk or yogurt decreased urease activity to approximately 11% of the control value in the small intestine (on the basis of grams of collected contents or total contents), and to 50% in the large intestine (only on the basis of grams of collected contents). Feeding the diet containing 25% lactose also decreased urease activity (on the basis of grams of collected contents or total contents) to about 20% of the control value in the small intestine, but not (P > 0.05) in the large intestine. Net ammonia production rate was correlated (r2 = 0.98) with urease activity in the large intestinal contents, and the rate of ammonia production from ureolysis represented about two thirds of the total. Feeding the cellulose diet decreased (P < 0.05) both urease activity and net ammonia production in the large intestine to approximately 30% of the control value. Weights of tissue and contents of the large intestine were much higher (P < 0.01) in rats fed diets containing milk products or lactose than in the control rats, but were not affected by consumption of the cellulose diet. Results of our studies indicate that feeding diets containing high levels of milk products (lactose) or cellulose reduces urease activity and net ammonia production in the rat intestine, and thus may be beneficial for improving animal and human health.     

Use of a live chlamydial vaccine to prevent ovine enzootic abortion

A lyophilised chlamydial vaccine was prepared from the 1B temperature-sensitive strain of ovine Chlamydia psittaci. Ewes inoculated with a low titre of the live vaccine four weeks before artificial insemination were challenged on day 70 of gestation with five UK field isolates of C psittaci, including strains A22 and S26/3 previously incorporated into a commercial inactivated vaccine. There was a significantly lower chlamydial abortion rate after challenge in the vaccinated group (7.1 per cent) than in the unvaccinated group (80 per cent). All the lambs born to the vaccinated ewes were viable and of good quality. The vaccine also reduced the number of infected ewes in the group and the severity of the infection. The compatibility of the chlamydial vaccine and a toxoplasma vaccine was also tested. The abortion rate of ewes vaccinated with the two vaccines at separate injection sites (16 per cent) was less than that of ewes vaccinated with both vaccines at one site (32 per cent).     

Fluorescence study on ligand induced conformational changes of human erythrocyte glucose transporter

The nanosecond time-resolved fluorescence and fluorescence lifetime quenching have been used to detect the conformational changes of human erythrocyte glucose transporter induced by its ligands. Results show that D-glucose can decrease the fluorescence lifetimes, while L-glucose exhibits no effect. The fluorescence lifetime quenching results also show that in the presence of D-glucose, the quenching efficiency of hypocrellin B (a hydrophobic quencher obtained from a parasitic fungus, growing in Yunnan, China) is lower than in the presence of L-glucose. It can be deduced that the conformational changes of human erythrocyte glucose transporter induced by D-glucose are different from those induced by L-glucose.     

Possible effect of pneumoperitoneum on the spreading of colon cancer tumor cells

Development of the central somatosensory system is profoundly modulated by the sensory periphery. Cauterization of facial whiskers alters the segregation pattern of barrels in rodents only during a few days just after birth (critical period). Although a molecular basis of the segregation of barrel neurons and the critical period for the anatomical plasticity observed in layer IV barrel neuron is not clear yet, the accumulating evidence suggests that neurotrophins modulate synaptic connections including central nervous system. In this study, we showed by in situ hybridization that mouse barrel side neurons express brain-derived neurotrophic factor (BDNF) mRNA and both catalytic and non-catalytic forms of trkB mRNA. Cautery of row C vibrissae on the right side of the face within 24 h after birth (post natal day 0, PND0) reduced the expression of BDNF and trkB mRNA from the division region between the contralateral row C barrels at PND7. The vibrissae in row A, C, and E were cauterized at PND0 followed by quantitative RT-PCR for BDNF and trkB mRNA with total RNA isolated from the barrel region at PND7. The result showed that BDNF, but not trkB, mRNA was increased several-fold in the contralateral barrel region. These data suggest that the expression of BDNF mRNA is differentially regulated between injured barrels and actively innervated barrels. The differential expression of the mRNA encoding neurotrophins and their receptors may be important in regulating the injury-dependent re-segregation of barrels.     

Paramagnetic metal scavenging by melanin: MR imaging

To evaluate the potential application of high performance liquid chromatography or HPLC in performing hemoglobin typing, comparison between this technique and routine methods was carried out. Blood specimens from Pediatric Hematology Unit, Research Center, Faculty of Medicine, Ramathibodi Hospital were examined by these methods. The level of Hb A2, Hb E and Hb F were compared. Hb A2 level determined by HPLC and electrophoresis was statistically significantly different but correlated well. Good correlation was found between Hb A2 level from HPLC compared with microcolumn chromatography although there was a statistical difference. No difference but very good correlation was found between the level of Hb E from HPLC compared with electrophoresis. Statistical difference was encountered when Hb F level determined by HPLC was compared to that determined by Betke alkaline denaturation test. However, good correlation was observed when the level of Hb F was greater than 2.0%. In conclusion, HPLC could be an alternative way of performing hemoglobin typing provided that Hb F is 10% or more, by calculating from the equation: Alk F = (0.83 x Hb F by HPLC) - 0.98.