Tyrosine supplementation mitigates working memory decrements during cold exposure.

In rats, dietary supplementation with the amino acid tyrosine (TYR) prevents depletion of central catecholamines observed during acute environmental stress. Concomitant changes in the animals' behavioral responses to stress suggest that TYR might have similar effects on central catecholamines and cognition in humans exposed to environmental stress. This study aimed to determine if severe cold exposure impairs human cognition and if dietary supplementation with TYR would ameliorate such deficits. Volunteers (N=19) completed three test sessions on different days (35 degrees C control/placebo, approximately 10 degrees C/placebo, approximately 10 degrees C/TYR) using a double-blind, within subjects design. During each session, volunteers completed two 90-minute water immersions and consumed a food bar (150 mg/kg TYR or placebo) before each immersion (total TYR 300 mg/kg). Cognitive performance, mood, and salivary cortisol were assessed. Cortisol was elevated in the cold (p<.01). Volunteers made fewer correct responses on a Match-to-Sample memory measure (p<.05) and reaction time (RT) and errors increased on a choice RT test (p<.01) in the cold. Self-reported tension (p<.01), depression (p<.05) and confusion (p<.01) also increased in the cold. When volunteers consumed TYR, correct responses increased on a Match-to-Sample memory measure (p<.05) and study time for the sample was shorter (p<.05), indicative of more rapid and accurate information processing. Finally, RT on the memory measure revealed a similar pattern across immersions for TYR and thermoneutral conditions, but not cold/placebo (p<.05). This study demonstrates cold exposure degrades cognitive performance and supplementation with TYR alleviates working memory decrements.

Cloning and characterization of the murine Vmd2 RFP-TM gene family.

Mutations in the human vitelliform macular dystrophy type 2 (VMD2) gene are known to cause autosomal dominant Best macular dystrophy (BMD), a degenerative disorder of the central retina. VMD2, together with VMD2L1, VMD2L2 and VMD2L3, belong to a closely related gene family characterized by several transmembrane (TM) spanning helical domains and an invariant arginine, phenylalanine and proline (RFP) tripeptide motif, thus termed VMD2 RFP-TM. The four genes are thought to encode a novel family of anion channels. We now report the cloning and characterization of the murine orthologs by combining biocomputational analyses and molecular genetic approaches. While the murine Vmd2, Vmd2l1 and Vmd2l3 genes are functional, murine Vmd2l2p was found to be a non-transcribed pseudogene. Expression profiling of the murine Vmd2 RFP-TM family members revealed tissue-restricted expression with predominant transcription of Vmd2 in testis, of Vmd2l1 in colon and of Vmd2l3 in heart. Differential splicing was observed for Vmd2l3 in a number of tissues (e.g. in brain, retina/RPE, kidney) although the functional importance of the splice variants remains to be determined.

[In vivo administration of purified supernatant of fetal and postnatal osteoblast cultures: initial results]. / In-vivo-Applikation aufgereinigter Uberstände fetaler und postnataler Osteoblastenkulturen: Erste Ergebnisse.

With increasing age of an organism, the osseous regenerative potential is reduced. In osteoblast-like cell cultures, cells of older donors that would not proliferate under standard conditions start to proliferate and express a differentiated phenotype when supplemented with the supernatant of fetal osteoblast-like cultures. The aim of this study was an evaluation of the fetal supernatant actions in vivo. Rat calvaria-derived osteoblasts of fetal and 21-day-old donors were isolated enzymatically and cultured. Their osteoblastic phenotype was confirmed by the expression of typical osteoblast synthesis products. The supernatant of the cultures of each age group was collected and pooled. The supernatant was purified by HPLC and concentrated approximately ten times. Additionally, several age-dependent differences within the purified protein fractions were documented by MALDI. After resuspension, the purified supernatant proteins were transferred on a collagen carrier and implanted into critical size defects of the calvaria of adult Wistar rats. In a control group, the collagen carriers were implanted containing isotonic salt solution. After 2, 4, and 8 weeks, a radiographic and histologic analysis of the regeneration process was performed which revealed differences in the progress of mineralization. The methods used in this study might help to identify age-dependent differences regarding the osteoblastic synthesis of osteoanabolic peptides and their impact on the regeneration of osseous defects.

Mutations in a novel gene, VMD2, encoding a protein of unknown properties cause juvenile-onset vitelliform macular dystrophy (Best's disease).

Vitelliform macular dystrophy (Best's disease) is an autosomal dominant, early-onset form of macular degeneration in which the primary defect is thought to occur at the level of the retinal pigment epithelium. Genetic linkage has mapped the disease locus to chromosome 11q12-q13.1 within a 980 kb interval flanked by markers at loci D11S4076 and uteroglobin. To identify the disease gene, we systematically characterized genes from within the critical region and analysed the coding regions for mutations in 12 patients from large multigeneration Best's disease families. Following this approach, we identified a novel gene of unknown function carrying heterozygous mutations in all 12 probands. Of these, 10 result in distinct missense mutations of amino acids that are highly conserved throughout evolution, spanning a phylogenetic distance from Caenorhabditis elegans to human, and include V9M, A10T, W24C, R25Q, R218Q, Y227N, Y227C, V235M, P297A and F305S. One deletion mutation, DeltaI295, was found in two families and segregates with the disease in both cases. Northern blot analysis reveals tissue-specific expression for this gene, exclusively in the retinal pigment epithelium. In conclusion, our data provide strong evidence that mutations in the gene that we have identified cause Best's disease.

A randomized, double-blind, placebo-controlled trial of cidofovir gel for the treatment of acyclovir-unresponsive mucocutaneous herpes simplex virus infection in patients with AIDS.

The safety and efficacy of cidofovir gel for treatment of acyclovir-unresponsive herpes simplex virus infections in AIDS patients was evaluated in a randomized, double-blind, multicenter trial. Cidofovir (0.3% or 1%) or placebo gel was applied once daily for 5 days. Ten of 20 cidofovir-treated and none of 10 placebo-treated patients had complete healing or >50% decreased area (P = .008); 30% of cidofovir-treated patients versus 0 placebo recipients had complete healing (P = .031). Viral shedding ceased in 13 (87%) of 15 cidofovir-treated and 0 of 9 placebo-treated patients (P = .00004). For cidofovir-treated patients, median time to complete or good response was 21 days, and median time to negative viral culture was 2 days (P = .025, P = .0001, respectively). Median lesion area decreases were 58% for cidofovir-treated versus 0 for placebo-treated patients (P = .005), and mean pain score changes were -1.84 versus -0.34 (P = .042). Application site reactions occurred in 25% of cidofovir-treated and 20% of placebo-treated patients; none was dose-limiting. Cidofovir therapy provided significant benefits in lesion healing, virologic effect, and pain reduction.

Novel, ligation-dependent PCR assay for detection of hepatitis C in serum.

A simple, sensitive, and specific ligation-dependent PCR (LD-PCR) method for the detection of hepatitis C virus (HCV) RNA in serum is described. The assay uses two DNA capture probes for RNA isolation and two DNA hemiprobes for subsequent PCR. Each capture probe has a 3' sequence complementary to the conserved 5' untranslated region of HCV RNA and a biotin moiety at the 5' end capable of interacting with streptavidin-coated paramagnetic beads. Each hemiprobe contains a sequence complementary to the 5' untranslated region in juxtaposition to one another and a common sequence for PCR primer binding. In guanidinium thiocyanate solutions, the capture probes and the hemiprobes form a hybrid with their target, and the hybrid can be isolated from serum by the binding of the capture probes to the paramagnetic beads in the presence of a magnetic field. The hemiprobes can then be linked to each other by incubation with T4 DNA ligase to form a full probe that serves as a template for a PCR. When serial 10-fold dilutions of synthetic HCV RNA (10(7) to 10 molecules) were tested, there was a good correlation between the amount of PCR product and the initial number of RNA molecules, with a sensitivity of 100 HCV RNA molecules per reaction. Twenty-four specimens that had been tested by either a branched DNA probe (bDNA) assay (13 specimens) or a reverse transcription PCR (RT-PCR) assay (11 specimens) were also analyzed by LD-PCR. The results showed a good correlation among LD-PCR, RT-PCR, and the bDNA assay. However, both LD-PCR and RT-PCR were more sensitive than the bDNA assay when the HCV titer was low.