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V Young

Publications and source records attributed to V Young.

At least 19 recordsLinked to original sources
PubMed2006

Real-time PCR detection and quantification of vector trichodorid nematodes and Tobacco rattle virus.

This report describes a novel diagnostic method for virus-vector trichodorid nematodes and associated Tobacco rattle virus (TRV) based on a real-time fluorogenic 5' nuclease PCR assay (TaqMan). Two independent primer/probe sets were designed targeting the 18S gene of the ribosomal cistron for the trichodorid species, Paratrichodorus pachydermus and Trichodorus similis. Assays using purified plasmid DNA containing clones of the 18S region and genomic DNA extracted from individuals from both nematode species displayed high specificity as no cros s-reaction was observed between the species or with two non-target trichodorid species Paratrichodorus anemones and Trichodorus primitivus. Relative quantification of target DNA present in unknown samples was performed by comparison of the fluorescence signals of the samples to those obtained from plasmid standard dilutions. Three primer/probe sets were also used to target TRV; one set for RNA1 and the two other sets for RNA2 of specific isolates (TRV-PpK20 and TRV-TpO1). Detection of both trichodorid species and TRV RNA1 and RNA2 from a single sample was achieved and field samples were used to demonstrate the potential of this assay to provide rapid, accurate and sensitive molecular information in relation to risk assessment in the field.

Analysis of Variance↗
PubMed2003

Direct measurements of urban OH reactivity during Nashville SOS in summer 1999.

Emissions of volatile chemicals control the hydroxyl radical (OH), the atmosphere's main cleansing agent, and thus the production of secondary pollutants. Accounting for all of these chemicals can be difficult, especially in environments with mixed urban and forest emissions. The first direct measurements of the atmospheric OH reactivity, the inverse of the OH lifetime, were made as part of the Southern Oxidant Study (SOS) at Cornelia Fort Airpark in Nashville, TN in summer 1999. Measured OH reactivity was typically 11 s(-1). Measured OH reactivity was 1.4 times larger than OH reactivity calculated from the sum of the products of measured chemical concentrations and their OH reaction rate coefficients. This difference is statistically significant at the 1sigma uncertainty level of both the measurements and the calculations but not the 2sigma uncertainty level. Measured OH reactivity was 1.3 times larger than the OH reactivity from a model that uses measured ambient concentrations of volatile organic compounds (VOCs), NO, NO2, SO2, and CO. However, it was within approximately 10% of the OH reactivity from a model that includes hydrocarbon measurements made in a Nashville tunnel and scaled to the ambient CO at Cornelia Fort Airpark. These comparisons indicate that 30% of the OH reactivity in Nashville may come from short-lived highly reactive VOCs that are not usually measured in field intensive studies or by US EPA's Photochemical Assessment Monitoring Stations.

Air Pollutants↗
PubMed2002

Occurrence and levels of indicator bacteriophages in bathing waters throughout Europe.

Somatic coliphages, F-specific RNA bacteriophages, bacteriophages infecting Bacteroides fragilis, Escherichia coli and enterococci were counted in bathing waters in the late spring and summer. We tested fresh and marine bathing waters from North, South, East and West Europe expected to contain between 100 and 500 E. coli per 100 ml, although wider ranges were sometimes found. Bacteriophages were counted after concentration, since a preliminary study proved that this step was necessary to obtain positive counts. During monitoring, a first-line quality control with reference materials for bacteria and bacteriophages was performed by all the laboratories participating in the study. The same microbes were also counted in raw sewage samples from various areas in Europe, where the bacterial indicators and the three groups of bacteriophages were detected in roughly the same numbers. All groups of bacteriophages were detected in both fresh and marine bathing waters throughout Europe. Reliable and complete results from 147 samples showed that for log-transformed values, E. coli and bacteriophages were slightly correlated. However, the slope of the regression line changed according to E. coli concentration and the correlation diminished when this concentration was close to zero per 100 ml. The ratios between E. coli and phages in bathing waters differed significantly from those in sewage. The relative amounts of bacteriophages, mainly somatic coliphages and phages infecting Bact. fragilis RYC2056, increased in bathing waters with low E. coli concentration, especially in seawater samples containing < 100 E. coli per 100 ml. The relationship of bacteriophages with respect to enterococci paralleled that of bacteriophages with respect to E. coli. Somatic coliphages and bacteriophages infecting Bact. fragilis are useful to predict the presence of some pathogens with the same origin as present bacterial indicators but with higher survival rates.

Bacteriophages↗
PubMed2002

Elevated expression of the genes encoding TNF-alpha and thromboxane synthase in leucocytes from patients with systemic sclerosis.

OBJECTIVE: To determine the expression of molecular markers of prostanoid/fatty acid signalling in leucocytes of patients with systemic sclerosis (SSc). METHODS: Gene expression in patient leucocytes was analysed using real-time fluorescence reverse transcriptase polymerase chain reaction for tumour necrosis factor alpha (TNF-alpha), thromboxane synthase (TXAS, CYP5A), prostacyclin synthase (CYP8A), monocyte chemoattractant protein-1 (MCP-1), peroxisome proliferator-activated receptors (PPAR) alpha, delta and gamma, low-density lipoprotein-associated lipoprotein lipase A(2) (LDL-PLA(2)), apolipoprotein E (apoE) and cholesterol 27-hydroxylase (CYP27). RESULTS: Both TNF-alpha and TXAS showed an increase in mean expression in the diseased group (6.3-fold and 5.6-fold respectively, P<0.0001). These two markers, along with CYP27, PPARgamma and apoE, provided predictive markers for the development of carotid artery disease within the SSc patient population. CONCLUSION: The elevated levels of TNF-alpha and thromboxane seen in SSc patient sera are paralleled by increases in the expression of the appropriate genes in leucocytes. This method will allow us to screen for a large number of candidate markers of disease in order to increase our understanding of the processes underlying the pathology of SSc.

Base Sequence↗
PubMed2001

Polymorph screening: influence of solvents on the rate of solvent-mediated polymorphic transformation.

Solvent-mediated polymorphic transformation is an efficient technique to obtain the most stable polymorph. The rate of solvent-mediated polymorphic transformation of sulfamerazine at 24 degrees C in various solvents and solvent mixtures is controlled by the nucleation rate of the more stable Form II. The transformation rate is generally higher in the solvent giving a higher solubility and is low in the solvent giving a low solubility (8 mmol/L). In these solvents, because of a high interfacial energy, the metastable zone may be wider than the solubility difference between two polymorphs, such that the critical free energy barrier for nucleation cannot be overcome. In addition to the solubility, the strength of the solvent-solute interactions is also important in determining the transformation rate. For sulfamerazine, the transformation rate is lower in the solvent with a stronger hydrogen bond acceptor propensity. Because solubility is higher in the solvent with stronger hydrogen bond acceptor propensity, the balance of solubility and strength of hydrogen bonding interactions between the solute and solvent molecules determines the polymorphic transformation rate. Degree of agitation and temperature also change the polymorphic transformation rate by influencing the crystallization kinetics of the more stable polymorph.

Anti-Infective Agents↗
PubMed2001

Meal palatability, substrate oxidation and blood glucose in young and older men.

We investigated the effects of food palatability on the thermic effect of feeding (TEF), substrate oxidation and circulating glucose and insulin. Healthy young men (23.4+/-1.0, SD, years, n=10) and older men (69.4+/-1.3, years, n=9) were resident in a metabolic unit for two 2-day study periods. On the second day of each period, they consumed in random order either a palatable test meal containing 2.93 MJ or a nonpalatable control meal containing the same foods in identical amounts but blended and freeze-dried into biscuit form. TEF and respiratory quotient (RQ) were measured over 6 h and blood samples were taken for measurement of glucose and insulin. Age group had no effect on TEF, RQ or circulating glucose other than to delay the time of peak TEF (P<0.002 for both meals). There was no significant effect of meal type on TEF, but RQ and circulating glucose were higher following consumption of the palatable meal (P<0.001 for both parameters). These results suggest that over 6 h postprandial, consumption of palatable foods does not increase TEF, but is instead associated with increased glycemic response and increased carbohydrate oxidation. These changes, combined with previous work on the glycemic index, predict an accelerated return of hunger and increased energy intake at subsequent meals following consumption of palatable vs. control foods. Further studies are needed to examine the possible mechanism for this previously suggested "second meal" effect of diet palatability on energy intake.

Adult↗
PubMed1999

[Immune status against measles and rubella among 4 Chilean groups of different ages].

BACKGROUND: Results of clinical and epidemiological studies confirm that no cases of measles have occurred in Chile since 1993. However, since covering of vaccination programs do not exceed 95%, an immunological surveillance for this disease is warranted. AIM: To know the immune status against measles and rubella in the Chilean population. MATERIAL AND METHODS: A serological census of a representative sample of communities with high (90% or more) or low immunization coverings was performed. Four sub samples along the country were selected: 122 children aged 18 months of age (stratum A), 1,276 children attending the first years of basic school (stratum B), 899 teenagers in their last high school year (stratum C) and 399 women attending a family planning clinic (stratum D). IgG antibodies against measles and rubella were measured using ELISA and hemagglutination inhibition techniques, respectively. RESULTS: Antibodies against measles and rubella were found in 96% and 94% of study subjects. No differences in these titres were found between different strata or communities with high or low vaccination covering. There is a high percentage of positive antibodies against measles among children of 18 months of age and a high percentage of antibodies against rubella among teenagers and women in family planning. Only 3% of the sample had not received any vaccine at the moment of the study. CONCLUSIONS: The high prevalence of antibodies against rubella allows to conclude that it is not necessary to consider this antigen in the next vaccination campaign. Due to the high prevalence of antibodies against measles, only the population older than 20 years old should be affected by the disease if this virus enters the country.

Adolescent↗
PubMed1996

Interlaboratory variation of GHb assays in Victoria, Australia.

OBJECTIVE: To determine the extent of interlaboratory variation and accuracy in the measurement of glycated hemoglobin (GHb). RESEARCH DESIGN AND METHODS: All laboratories that measure glycated hemoglobin in the State of Victoria, Australia, were invited to participate, and positive responses were received from 27 to 30 laboratories. An aliquot of blood drawn from three patients with diabetes and varied glycemia and from one nondiabetic subject was sent to each participating laboratory. Distribution of results was analyzed according to the reported results and their variance from an assigned reference value and were expressed as differing from this latter value as percentage bias and in absolute terms. A bias > or = 10% or an absolute difference of > or = 1% HbA1c from the reference value was considered significant. RESULTS: Reported results for the same blood sample ranged from 4.1 to 5.8%, 5.1 to 8.2%, 6.7 to 9.3%, and 10.1 to 14.7% for the specimens from the nondiabetic subject and the diabetic patients with good, moderate, and poor glycemic control, respectively. The proportion of laboratories with results that differed by > or = 10% bias from the reference value were 39% (12 of 30), 29% (9 of 30), 16% (5 of 30), and 32% (10 of 30), and the proportion reporting results that differed by > or = 1% HbA1c in absolute terms from the reference values were 3% (1 of 30), 6% (2 of 30), 16% (5 of 30), and 23% (7 of 30) for the specimens from the nondiabetic subject and the diabetic patients with good, moderate, and poor glycemic control, respectively. CONCLUSIONS: A substantial degree of interlaboratory variation for GHb measurement exists in Victoria, Australia. This may lead to difficulties in interpretation when GHb is assayed by different laboratories in the same patient over time. Interlaboratory standardization may be achievable by calibration to a standard assigned by a reference laboratory and distributed to all laboratories measuring GHb.

Diabetes Mellitus↗
PubMed1994

Lack of cardioprotective efficacy of allopurinol in coronary artery surgery.

OBJECTIVE: To examine the cardioprotective efficacy of allopurinol in patients undergoing elective coronary artery surgery. DESIGN: Prospective randomised trial. SETTING: London teaching hospital. PATIENTS: Twenty patients with at least moderately good left ventricular function undergoing elective coronary artery surgery and requiring at least two bypass grafts. INTERVENTIONS: Patients were randomised to receive allopurinol (1200 mg in two divided doses) or to act as controls. MAIN OUTCOME MEASURE: The primary determinant of the efficacy of myocardial protection was serial measurement (preoperatively and subsequently at one, six, 24, and 72 hours after the end of cardiopulmonary bypass) of cardiac troponin T (cTnT) a highly sensitive and specific marker of myocardial damage. Additional evidence was provided by serial measurement of the MB-isoenzyme of creatine kinase (CK-MB) and myoglobin, ECG changes, and clinical outcome. RESULTS: There was no significant difference in age, ejection fraction, number of grafts, bypass times, or cross clamp times between the two groups. In both groups there was a highly significant (p < 0.01) rise in cTnT, CK-MB, and myoglobin. Peak concentrations were reached between one (CK-MB and myoglobin) and six hours (cTnT) after the end of cardiopulmonary bypass. At 72 hours cTnT concentrations were six times higher than baseline concentrations whereas CK-MB and myoglobin were approximately double baseline concentrations. There was no significant difference in cTnT, CK-MB, or myoglobin between the allopurinol and control groups at any time. There was no diagnostic ECG evidence of perioperative infarction in any patient. CONCLUSION: Unlike previous reports this study did not show that allopurinol had a cardioprotective effect in patients with good left ventricular function undergoing elective coronary artery surgery.

Allopurinol↗
PubMed1994

Transthyretin (prealbumin) in health and disease: nutritional implications.

The name "transthyretin" reflects the dual physiological roles of this tetrameric unglycosylated plasma protein. TTR is one of three specific carrier proteins involved in the transport of both thyroid hormones and of retinol through the mediation of RBP. TTR is a product of the visceral compartment, and its hepatic synthesis is exquisititely sensitive to both the adequacy and levels of protein and energy intakes--hence the proposal of TTR as a nutritional marker. To date, 38 TTR variants have been described, most of which are associated with variable degrees of cardiac and/or neural tissue amyloid deposits. All known variants arise from a single AA substitution due to single point mutation in the coding region of the TTR gene. Under acute stress conditions, the synthesis of TTR, RBP, and CBG is abruptly depressed by a cytokine-directed orchestration of new metabolic priorities, with a redistribution of organ and tissue protein pools. It is proposed that TTR, RBP, and CBG behave as acute-booster reactants (ABRs), actively participating in the cascade of metabolic events characterizing the stress reaction along pathways best explained by the free hormone/vitamin hypothesis. The latter is governed by the law of mass action--the spontaneous dissociation and instant uptake by hepatocytes of the ligands freed from their specific carrier proteins, which creates a transient hyperthyroid, hyperretinoid, and hypercortisolic climate. This response generally does not exceed four or five days because the initial impact of injury normally subsides, but it may last longer if complications occur. The magnitude and adequacy of the stress responses depend on the preceding nutritional status as assessed by TTR plasma levels and are proportionate to the severity of insult. Clinical, animal, and molecular studies concur to demonstrate the dualistic stimulatory or inhibitory effects triggered by the ligands, whose unmetabolized fractions are excreted in the urinary output. Thyroid hormones and retinoids appear to control the early maturation processes and the synthesis of primary transcripts, whereas cortisol preferentially modulates the secondary responses and confers a protective effect on healthy tissues. During acute stress, the evolutionary patterns of visceral proteins and inflammatory markers exhibit compulsory mirror images. However, they change in independent ways under more chronic circumstances. A relatively simple biochemical micromethod based on the simultaneous measurement of plasma TTR, albumin, CRP, and orosomucoid aggregated into a PINI is proposed for the early recognition and follow-up of both nutritional and inflammatory facets of the disease spectrum.

Amino Acid Sequence↗
PubMed1993

Long-term glycemic control and the rate of progression of early diabetic kidney disease.

In this prospective study of 11.9 years duration (range 9 to 14), we examined the progression of albuminuria prior to and after the onset of microalbuminuria [albumin excretion rate (AER): 20 to 200 micrograms/minute]. Glycated hemoglobin (HbA1), AER and blood pressure were measured every six months. Twenty-two (13 type I, 9 type II) patients were identified in whom AER increased progressively (progressors). These patients were compared with 22 others matched for age, duration and type of diabetes in whom AER did not change significantly during the study period (non-progressors). In the progressors, the rate of increase in AER correlated with mean HbA1 for the study period in patients with type I (r = 0.68, P < 0.01) and type II diabetes (r = 0.71, P < 0.05). Furthermore, AER began increasing well before the conventional 20 micrograms/minute threshold of microalbuminuria had been reached and within the first five years of diagnosis of type I diabetes. We conclude that in predisposed diabetic patients, long-term glycemic control is correlated with the rate of development of early renal abnormalities. Repeated measurements of AER from the time of diagnosis may be useful in the early detection of patients who will develop microalbuminuria and ultimately overt diabetic nephropathy.

Adolescent↗
PubMed1993

Microbial composition and pattern of antibiotic resistance in subgingival microbial samples from patients with refractory periodontitis.

A series of 993 subgingival microbial samples sent to a diagnostic microbiology laboratory included 196 samples that could be identified as compatible with a clinical diagnosis of refractory or recurrent periodontitis. In descending order of prevalence the associated microbiota included Bacteroides forsythus (84%), spirochetes (83%), motile rods (76%), Fusobacterium species (68%), Porphyromonas gingivalis (63%), Campylobacter rectus (47%), Capnocytophaga species (38%), Prevotella intermedia (23%), Peptostreptococcus micros (18%), Actinobacillus actinomycetemcomitans (16%), Candida (14%), enteric rods (9%), Staphylococcus species, not including aureus (5.6%). Eikenella corrodens (3%), Staphylococcus aureus (1.5%), and Enterococcus species (< 1%). Antibiotic resistance to tetracycline, penicillin G, or metronidazole was particularly noticeable for enteric rods, Fusobacterium species, Capnocytophaga species, Staphylococcus, and Actinobacillus actinomycetemcomitans. It was largely absent for Campylobacter rectus. No antibiotic sensitivity data were obtained for Porphyromonas gingivalis or Bacteroides forsythus, as these species were detected by immunofluorescence. The results indicate that a substantial number of microorganisms associated with refractory periodontitis are variably resistant to commonly-used antibiotics. Diagnostic microbiology must be considered an essential adjunct to the therapist faced with periodontal lesions refractory to conventional treatment.

Adult↗