Effects of real and sham whole-body mechanical vibration on spinal excitability at rest and during muscle contraction.

We examined the effects of whole-body mechanical vibration (WBV) on indices of motoneuronal excitability at rest and during muscle contraction in healthy humans. Real and sham WBV at 30 Hz had no effect on reflexes measured during muscle contraction. Real WBV at 30 and 50 Hz depressed the H-reflex ∼45%. These depressions diminished across the five inter-bout rest intervals. The depression converted to 27% and 7% facilitation over the 15-min long recovery period following real WBV at 30 and 50 Hz, respectively. The depression, measured during the inter-bout rest, correlated r = 0.48 (P = 0.007) with the subsequent facilitation, measured during the follow-up. The depression produced by sham vs real WBV was significant but less (23%), recovered faster, and the facilitation was absent in the 15-min long follow-up period. WBV produced time-varying depression followed by facilitation of the H-reflex at rest. A lack of change in volitional wave suggests that WBV did not affect the efferent neural drive.

Human cytomegalovirus microRNAs.

MicroRNAs (miRNAs) are approximately 22 nucleotide RNAs that mediate the posttranscriptional regulation of gene expression. miRNAs regulate diverse cellular processes such as development, differentiation, cell cycling, apoptosis, and immune responses. More than 400 miRNAs have been identified in humans and it is predicted that over 30% of human gene transcripts are regulated via miRNAs. Since 2004, many viral miRNAs have been described in several families of viruses. More than half of currently known viral miRNAs are encoded by viruses of the human Herepsviridae and 14 miRNAs have been found to be encoded by Human cytomegalovirus (HCMV). Thus far, HCMV is the only betaherpesvirus in which miRNAs have been described and these miRNAs possess many characteristics, including their genomic arrangement and temporal/spatial expression, which distinguish them from the other known herpesvirus miRNAs described. As a herpesvirus, HCMV establishes infection for the life of the host characterized by latent infection with periodic reactivation for production and spread of infectious progeny. This multifaceted life cycle of the herpesvirus requires an abundance of gene products and regulatory elements that makes cytomegalovirus genomes one of the most complex among human viruses. The defining characteristics of the cytomegalovirus and the minimal impact on genome size afforded by miRNAs inform the logic of virus-encoded miRNAs.

Rapid prototyping of pulse oximeter.

Measurement of oxygen saturation levels in blood is a vital activity during most medical treatments. A pulse oximeter is a device most commonly used to perform this measurement. It provides convenient, non-invasive and continuous monitoring of oxygen levels in a human body. However, it is often a tedious task to select the appropriate hardware and software components to manufacture a pulse oximeter that gives accurate results. This paper describes a student project, which had the goals to expose the student to this important technique of applying rapid prototyping methods to the design of a state of the art pulse oximeter.

Analysis of a microbial community oxidizing inorganic sulfide and mercaptans.

Successful treatment of refinery spent-sulfidic caustic (which results from the addition of sodium hydroxide solutions to petroleum refinery waste streams) was achieved in a bioreactor containing an enrichment culture immobilized in organic polymer beads with embedded powdered activated carbon (Bio-Sep). The aerobic enrichment culture had previously been selected using a gas mixture of hydrogen sulfide and methyl mercaptan (MeSH) as the sole carbon and energy sources. The starting cultures for the enrichment consisted of several different Thiobacilli spp. (T. thioparus, T. denitrificans, T. thiooxidans, and T. neopolitanus), as well as activated sludge from a refinery aerobic wastewater treatment system and sludge from an industrial anaerobic digester. Microscopic examination (light and SEM) of the beads and of microbial growth on the walls of the bioreactor revealed a great diversity of microorganisms. Further characterization was undertaken starting with culturable aerobic heterotrophic microorganisms (sequencing of PCR-amplified DNA coding for 16S rRNA, Gram staining) and by PCR amplification of DNA coding for 16S rRNA extracted directly from the cell mass, followed by the separation of the PCR products by DGGE (denaturing gradient gel electrophoresis). Eight prominent bands from the DGGE gel were sequenced and found to be closest to sequences of uncultured Cytophagales (3 bands), Gram-positive cocci (Micrococcineae), alpha proteobacteria (3 bands), and an unidentified beta proteobacterium. Culturable microbes included several genera of fungi as well as various Gram-positive and Gram-negative heterotrophic bacteria not seen in techniques using direct DNA extraction.

Inhibition of inducible nitric oxide synthase by acetamidine derivatives of hetero-substituted lysine and homolysine.

The synthesis and in vitro evaluation of the acetamidine derivatives of hetero-substituted lysine and homolysine analogues have identified potent inhibitors of human nitric oxide synthase enzymes, including examples with marked selectivity for the inducible isoform.

Carcinoma of the bronchus in the Yorkshire region of England 1976-1990: trends since 1984.

We wished to confirm that, in patients with lung cancer, trends in demography and histology, together with modest improvements in survival, first seen in the 1976-1983 cohorts, continued to 1990. All lung cancer patients resident in Yorkshire are notified to the Cancer Registry, whose database was analysed for this report. A total of 38,275 patients were notified. There was no change in annual notification for males but an increase from 513 to 815 annual notifications in females between 1976 and 1990. Mean age increased by 3 yrs, in males to 67.4 yrs and in females to 67.2 yrs. Histological confirmation rate increased from 43% to 60% (mean age from 60.8 to 64.5 yrs). Annual notifications of adenocarcinoma increased consistently from 108 to 253. Two year surgical survival improved from 37.4 to 44.3%, doubling in subjects aged > or = 70 yrs to 43.8%. Over the 15 year period, there was no improvement in survival aged < 60 yrs, but a significant improvement in the 60-69 and > or = 70 yrs age groups. Analysis of survival by quartiles showed significant improvement at all levels (first interval 20 to 24 days, median 79 to 91 days, third interval 224 to 266 days). The modest improvement in outlook was confirmed, confined to older subjects after 1983, and partially masked by increasing age. Survival after surgery is now independent of age.

Development and evaluation of a novel dissolution apparatus for medicated chewing gum products.

A novel dissolution apparatus was developed for medicated chewing gum products. A prototype gum product containing phenylpropanolamine hydrochloride (PPA) was used to evaluate the apparatus. The apparatus consists of a conical Teflon base and a rotating, ribbed Teflon plunger suspended in a dissolution vessel. Parameters evaluated were rotation speed, plunger frequency, medium volume, medium type, medium sampling location, number of plunger ribs, and number of gum pieces. Samples were taken over a 20-min period and samples were analyzed by HPLC. Cumulative percentage released-versus-time profiles were obtained for each parameter evaluated. Statistical analysis of the gum product indicated that the only significant differences occurred at the lowest rotation speed and lowest plunger frequencies. A Level A correlation was found between the in vitro release profile for the 20-rpm and 30-cycles/min plunger frequency and the in vivo chew-out study.

Synthesis and applications of oligoribonucleotides with selected 2'-O-methylation using the 2'-O-[1-(2-fluorophenyl)-4-methoxypiperidin-4-yl] protecting group.

The synthesis of base protected 5'-O-dimethoxytrityl-2'-O-[1-(2- fluorophenyl)-4-methoxypiperidin-4-yl]-3'-O-(2-cyanoethyl N,N-diisopropylphosphoramidites) is described, using phenoxyacetyl protection for the exocyclic amino groups of guanosine and adenosine and acetyl protection of the amino group of cytidine. High yield assembly of these building blocks into oligoribonucleotides on aminopropyl controlled pore glass was achieved using 5-(4-nitrophenyl)-1H-tetrazole as activator. Mixed sequences containing selected 2'-O-methylation were also synthesised and their significance for the study of RNA biochemistry is discussed.

The synthesis of protected 5'-amino-2',5'-dideoxyribonucleoside-3'-O-phosphoramidites; applications of 5'-amino-oligodeoxyribonucleotides.

Synthetic routes to the four appropriately protected 5'-amino-2',5'-dideoxyribonucleoside-3'-O-(2-cyanoethyl N,N-diisopropylphosphoramidites) have been developed. The structures of all intermediates were confirmed by 13C n.m.r. spectroscopy. These building blocks have been used to prepare 5'-amino-oligodeoxyribonucleotides, which can be coupled to a wide variety of compounds, in particular metal cluster derivatives, but also fluorophores and biotin derivatives, thus generating a variety of very useful probes. Brief mention is made of a tetrairidium cluster derivative of 5'-amino-d[CCGATATCGG], which has been cocrystallised with EcoRV, and will be used for electron microscopy studies.

The synthesis of protected 5'-mercapto-2',5'-dideoxyribonucleoside-3'-O-phosphoramidites; uses of 5'-mercapto-oligodeoxyribonucleotides.

The syntheses of the four novel, base protected 5'-(S-triphenylmethyl)mercapto-2',5'-dideoxyribonucleoside-3 '-O-(2-cyanoethyl N,N-diisopropylphosphoramidites) are described. These compounds have been used to prepare 5'-(S-triphenylmethyl) mercapto-oligodeoxyribonucleotides, which are readily purified by reversed phase h.p.l.c., owing to the highly lipophilic trityl group. After cleavage of the S-trityl group by silver or mercuric ions, the free thiol moiety can be coupled to a wide variety of reagents, generating very useful probes. Fluorescent labelled 5'-mercapto-oligodeoxyribonucleotides are being used for automated DNA sequencing without radioactivity, and heavy metal labelled 5'-mercapto-oligonucleotides will be used in X-ray crystallography.

Highly efficient oligodeoxyribonucleotide synthesis using fully base protected phosphodiester building blocks carrying 2-(1-methylimidazol-2-yl) phenyl protection of the phosphate.

Four fully base protected phosphodiester building blocks have been synthesised and fully characterised. The phosphate protecting group used was the 2-(1-methylimidazol-2-yl)phenyl group, enabling intramolecular catalysis of the condensation step in oligodeoxyribonucleotide synthesis by the solid phase phosphotriester method. Cycle times of about 12 min could thus be achieved. Moreover, the used of extra protecting groups on deoxythymidine and 2'-deoxyguanosine resulted in much cleaner oligodeoxyribonucleotides as evidenced by ion-exchange and reversed phase h.p.l.c.

Chemical synthesis of oligonucleotides containing a free sulphydryl group and subsequent attachment of thiol specific probes.

Oligonucleotides containing a free sulphydryl group at their 5'-termini have been synthesised and further derivatised with thiol specific probes. The nucleotide sequence required is prepared using standard solid phase phosphoramidite techniques and an extra round of synthesis is then performed using the S-triphenylmethyl O-methoxymorpholinophosphite derivatives of 2-mercaptoethanol, 3-mercaptopropan (1) ol or 6-mercaptohexan (1) ol. After cleavage from the resin and removal of the phosphate and base protecting groups, this yields an oligonucleotide containing an S-triphenylmethyl group attached to the 5'-phosphate group via a two, three or six carbon chain. The triphenylmethyl group can be readily removed with silver nitrate to give the free thiol. With the three and six carbon chain oligonucleotides, this thiol can be used, at pH 8, for the attachment of thiol specific probes as illustrated by the reaction with fluorescent conjugates of iodoacetates and maleiimides. However, oligonucleotides containing a thiol attached to the 5'-phosphate group via a two carbon chain are unstable at pH 8 decomposing to the free 5'-phosphate and so are unsuitable for further derivatisation.

Effect of diet on urinary excretion of VMA, HVA, metanephrine, and total free catecholamine in normal preschool children.

Quantitation of the urinary metabolites of catecholamines, including VMA, HVA, and metanephrines, from six normal preschool children was performed during a normal diet, a restricted diet, and a diet with increased amounts of vanilla, vanillin, and phenolic acids. Ingestion of these substances has been suspected of producing elevated values of urinary catecholamines and their metabolites. Urine was collected on the fourth day of each diet in two consecutive 12-hour aliquots, beginning at 8:00 AM. Statistically significant diurnal variation in excretion of all three metabolites and total free catecholamines (epinephrine, norepinephrine, and dopamine) was demonstrated. Diet did not alter exceretion of total free catecholamines or any of the three metabolites. This study suggests that a three-day restricted diet is not necessary prior to screening children for neuroblastoma when using quantitative assay methods and that all screening tests should be performed on a 24-hour urine sample.