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Biomedical subjects

J Peterson

Publications and source records attributed to J Peterson.

At least 19 recordsLinked to original sources
PubMed2006

Double-blind, randomized, placebo-controlled study to evaluate the effects of tegaserod on gastric motor, sensory and myoelectric function in healthy volunteers.

BACKGROUND: The effects of tegaserod on gastric accommodation and postprandial satiety remain unclear. AIM: To compare the effects of tegaserod 6 mg twice daily vs. placebo on gastric volumes, postprandial symptoms, gastric emptying, small bowel transit and the surface electrogastrogram in female and male healthy volunteers. METHODS: Randomized, double-blind, placebo-controlled study evaluated gastric function before and after 7 days of tegaserod 6 mg twice daily (n = 21) vs. placebo (n = 20) in healthy volunteers. Validated methods were used to study gastric emptying, myoelectrical activity, volumes and satiation postnutrient challenge. RESULTS: There were no significant effects of tegaserod on the primary endpoints assessing gastric function: emptying of solids or liquids, total gastric volumes or myoelectrical activity. Maximum tolerated volume and aggregate symptom score with nutrient challenge on placebo were 1,035 mL (+/-44) and 130 (+/-15) vs. 989 mL (+/-43) and 117 (+/-15) during tegaserod, respectively (all P = N.S.). Postprandial change in proximal gastric volume by single photon emission-computed tomography was decreased in females on tegaserod (246 +/- 30) vs. placebo (358 +/- 32) (P = 0.015). Proximal fasting volumes in females were increased on tegaserod (126 +/- 12) vs. placebo (92 +/- 13) (P = 0.066). CONCLUSIONS: While tegaserod decreased proximal gastric volume change after a meal, it does not appear to have significant effects on gastric motor and sensory function in healthy individuals. Further studies are required in patients with disturbances of gastric motor and sensory function.

Administration, Oral↗
PubMed2006

Accuracy of the 7-8-9 Rule for endotracheal tube placement in the neonate.

OBJECTIVE: To determine accuracy of the 7-8-9 Rule in a cohort of neonates. STUDY DESIGN: This study was cross-sectional in design. Seventy-five consecutive neonates who required oral intubation from June 2004 to November 2004 for cardiopulmonary failure, respiratory distress, or surfactant administration were the subjects of this study. The initial endotracheal tube (ETT) depth of insertion was determined using either an estimated birth weight or actual weight in the 7-8-9 Rule calculation followed by auscultation and subsequent adjustment if necessary. Midtracheal position was identified as the point halfway between the inferior clavicle and carina on a chest radiograph. The initial depth was compared to the midtracheal depth to determine clinical accuracy of the 7-8-9 Rule. The depth predicted by the 7-8-9 Rule was also calculated using only actual weights. This predicted depth was compared to the midtracheal depth to determine true accuracy of the 7-8-9 Rule. Accuracy was determined using mean paired differences with 95% confidence intervals (CI) between initial or predicted depth and ideal, midtracheal ETT depth. Linear regression was used to adjust for confounding variables. RESULTS: Mean (range) gestational age was 32 weeks (23 to 44 weeks) and weight was 2001 g (490 to 4400 g). Eighteen (24%) infants weighed 1000 g or less, 20 (27%) weighed between 1001 and 2000 g, 21 (28%) weighed between 2001 and 3000 g, 15 (20%) weighed between 3001 and 4000 g, and one (1%) weighed more than 4000 g. Thirteen of the 18 extremely low birth weight infants weighed <750 g. The initial depth of insertion was 0.004 cm above midtracheal position (95% CI -0.13 to 0.14, P = 0.96). After controlling for head position, the initial depth did not significantly differ from the midtracheal position among weight groups. Predicted depth using the 7-8-9 Rule placed the ETT 0.12 cm above midtracheal position (95% CI -0.30 to 0.06, P = 0.20). However, after controlling for head position, the 7-8-9 Rule positioned the ETT significantly below midtracheal position in infants weighing <750 g (mean 0.62 cm; 95% CI 0.30 to 0.93, P=0.002). CONCLUSIONS: The 7-8-9 Rule appears to be an accurate clinical method for endotracheal tube placement in neonates weighing more than 750 g. When the 7-8-9 Rule is applied to infants weighing <750 g, caution is warranted. The current rule may lead to an overestimated depth of insertion and potentially result in clinically significant consequences.

Body Weight↗
PubMed2006

Effect of H-7 and Lat-B on retinal physiology.

PURPOSE: To investigate the effects of H-7 and Latrunculin B (Lat-B) on retinal vascular permeability and electrophysiology at concentrations that increase outflow facility in monkeys. METHODS: One eye of 1 rhesus and 22 cynomolgus monkeys received an intravitreal bolus injection of H-7 or Lat-B; the opposite eye received vehicle. Multifocal electroretinograms (mfERGs), and photopic and scotopic full-field electroretinograms (ffERGs, sERGs) were recorded in subsets of monkeys at baseline and at multiple time-points post-H-7 or Lat-B. Vitreous fluorophotometry (VF) and fluorescein angiography (FA) were also performed. RESULTS: No differences between the H-7 or Lat-B treated and control eyes were found in ffERGs, mfERGs, sERGs, or in FAs in any monkey. No significant difference was found in vitreous fluorescein levels between H-7 treated or Lat-B treated vs. control eyes. CONCLUSIONS: No effect on retinal vascular permeability or retinal electrophysiology was apparent after intravitreal administration of H-7 or Lat-B at doses that increase outflow facility and lower IOP when given intracamerally.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2005

Do health care providers' attitudes towards back pain predict their treatment recommendations? Differential predictive validity of implicit and explicit attitude measures.

The current study aimed to measure the differential predictive value of implicit and explicit attitude measures on treatment behaviour of health care providers. Thirty-six physiotherapy students completed a measure of explicit treatment attitude (Pain Attitudes And Beliefs Scale For Physiotherapists-PABS-PT) and a measure of implicit treatment attitude (Extrinsic Affective Simon Task-EAST). Furthermore, they gave treatment recommendations for a patient simulating back pain on three video scenes. The implicit and explicit measures of attitudes were only weakly related to each other. However, both were differentially related to treatment recommendations. The implications of the differential predictive value of implicit and explicit attitude measures for treatment behaviour are discussed.

Adult↗
PubMed2004

Potential applications of nicotinic ligands in the laboratory and clinic.

The nicotinic acetylcholine receptor (nAChR) is a receptor, ion channel complex composed of five polypeptide subunits. There are many different nAChR subtypes constructed from a variety of different subunit combinations. This structural diversity contributes to the varied roles of nAChRs in the peripheral and central nervous system, and this diversity offers an excellent opportunity for chemists who are producing ligands. Subunit specific ligands could have wide and varied effects in the laboratory as experimental tools and in the clinic as therapeutic agents. Because presynaptic nAChRs have been shown to enhance the release of many neurotransmitters, new nicotinic ligands that potentiate nAChR activity would be very useful. Such ligands could enhance the release of various neurotransmitters during degenerative diseases that cause neurotransmitter systems to decrease their output. For example, boosting the release from cholinergic neurons would help patients with Alzheimer's disease, and boosting the release from dopaminergic neurons would help patients with Parkinson's disease.

Alzheimer Disease↗
PubMed2004

Calcium supplementation on bone loss in postmenopausal women.

BACKGROUND: Although calcium is one the simplest and least expensive strategies for preventing osteoporotic fractures calcium supplementation is nevertheless not without controversy (Kanis 1989; Nordin 1990). The Food and Drug Administration in the US has permitted a bone health claim for calcium-rich foods, and the NIH in its Consensus Development Process approved a statement that high calcium intake reduces the risk of osteoporosis. OBJECTIVES: To assess the effects of calcium on bone density and fractures in postmenopausal women. SEARCH STRATEGY: We searched Cochrane Controlled Register, MEDLINE and EMBASE up to 2001, and examined citations of relevant articles and proceedings of international meetings. SELECTION CRITERIA: Trials that randomized postmenopausal women to calcium supplementation or usual calcium intake in the diet and reported bone mineral density of the total body, vertebral spine, hip, or forearm or recorded the number of fractures, and followed patients for at least one year were considered for inclusion. DATA COLLECTION AND ANALYSIS: Three independent reviewers assessed the methodologic quality and extracted data for each trial. For each bone density site (lumbar spine, total body, combined hip and combined forearm), we calculated the weighted mean difference in bone density between treatment and control groups using the percentage change from baseline. We constructed regression models in which the independent variables were year and dose, and the dependent variable was the effect size. This regression was used to determine the years across which pooling was appropriate. Heterogeneity was assessed. For each fracture analysis we calculated a risk ratio. MAIN RESULTS: Fifteen trials, representing 1806 participants, were included. Calcium was more effective than placebo in reducing rates of bone loss after two or more years of treatment. The pooled difference in percentage change from baseline was 2.05% (95% CI 0.24 to 3.86) for total body bone density, 1.66% (95% CI 0.92 to 2.39) for the lumbar spine at 2 years, 1.60% (95% CI 0.78 to 2.41) for the hip, and 1.91% (95% CI 0.33 to 3.50) for the distal radius. The relative risk of fractures of the vertebrae was 0.79 (95% CI 0.54 to 1.09); the relative risk for non-vertebral fractures was 0.86 (95% CI 0.43 to 1.72). REVIEWER'S CONCLUSIONS: Calcium supplementation alone has a small positive effect on bone density. The data show a trend toward reduction in vertebral fractures, but it is unclear if calcium reduces the incidence of non vertebral fractures.

Bone Density↗
PubMed2004

Flavonoids, vitamin C and adenocarcinoma of the stomach.

OBJECTIVE: To examine the role of six flavonoid classes (flavanones, flavan-3-ols, flavonols, flavones, anthocyanidins and isoflavones) and vitamin C in the aetiology of stomach cancer. METHODS: Case-control study undertaken in Greece in the 1980s. Dietary information was obtained from 110 patients with incident stomach adenocarcinoma and 100 control patients. Flavonoid estimates were based on the recently released database of the US Department of Agriculture. RESULTS: In models including sociodemographic variables, energy intake, vegetables, fruits and, alternatively, vitamin C the six flavonoid classes, only flavanones and vegetables remained significantly inversely associated with stomach cancer risk. The odds ratio (95% confidence intervals) per one standard deviation increase of intake of flavanones was 0.55 (0.31-0.96) whereas for vitamin C it was 1.05 (0.46-2.41). When fruits and vegetables were not adjusted for, both vitamin C and several flavonoid categories were inversely associated with stomach cancer risk, but these associations could be attributed to other compounds in these foods. CONCLUSIONS: Among the major flavonoid classes studied, only flavanone intake is inversely associated with stomach cancer risk and could account for the apparent protective effect of fruit intake against this form of cancer. Additional factors, however, are likely to be involved in the consistent protection conveyed by vegetables.

Adenocarcinoma↗
PubMed2004

Intake of specific flavonoid classes and coronary heart disease--a case-control study in Greece.

OBJECTIVE: Dietary intake of flavonoids has been reported to protect against coronary heart disease (CHD) risk, but associations of specific classes of flavonoids with CHD have not been adequately studied. DESIGN: Hospital-based case-control study relying on interviewer administered questionnaires. SETTING: Cardiology Department of the University of Athens Medical School in the Hippokrateion General Hospital (1990-1991). SUBJECTS: Cases were 329 patients with electrocardiographically confirmed first coronary infarct or a first positive coronary arteriogram, or both (participation fraction 93%). Controls were 570 patients admitted to the same hospital for minor conditions unrelated to nutrition (participation fraction 95%). All cases and controls were interviewed in the hospital wards by experienced interviewers, and a 110-item food frequency questionnaire was administered. RESULTS: There was statistically significant evidence (P approximately 0.03) for an inverse association between intake of flavan-3-ols and CHD risk, an increase of about 21 mg per day corresponding to a 24% decrease in CHD risk. The inverse association between flavan-3-ols and CHD risk was largely accounted for by the intake of wine and to a lesser extent tea. For none of the other flavonoid classes was there statistically significant evidence of an association. CONCLUSION: Flavan-3-ols, which are largely found in wine and tea, are inversely associated with, and may be protective against, coronary heart disease.

Case-Control Studies↗
PubMed2003

Flavonoid intake and breast cancer risk: a case--control study in Greece.

Flavonoids have been investigated for possible inverse associations with various chronic degenerative diseases, but there are no epidemiologic data concerning a possible association between several of the main flavonoid categories and breast cancer risk. We have applied recently published data on the flavonoid content of several foods and beverages on dietary information collected in the context of a large case-control study of 820 women with breast cancer and 1548 control women, conducted in Greece. We found a strong, statistically significant inverse association of flavone intake with breast cancer. The odds ratio for an increment equal to one standard deviation of daily flavone intake (i.e. 0.5 mg day(-1)) was 0.87, with 95% confidence interval 0.77-0.97. The association persisted after controlling for fruit and vegetable consumption, or for other flavonoid intake. This inverse association is compatible with and may explain the reported inverse association of breast cancer with consumption of vegetables, particularly leafy vegetables. After controlling for dietary confounding, there was no association of breast cancer risk with flavanones, flavan-3-ols, flavonols, anthocyanidins or isoflavones.

Breast Neoplasms↗
PubMed2003

Detection and identification of carprofen and its in vivo metabolites in greyhound urine by capillary gas chromatography-mass spectrometry.

Rimadyl (carprofen) was administered orally to the racing greyhound at a dose of 2.2 mg kg(-1). Following both alkaline and enzymatic hydrolysis, postadministration urine samples were extracted by mixed mode solid-phase extraction (SPE) cartridges to identify target analyte(s) for forensic screening and confirmatory analysis methods. The acidic isolates were derivatised as trimethylsilyl ethers (TMS) and analysed by gas chromatography-mass spectrometry (GC-MS). Carprofen and five phase I metabolites were identified. Positive ion electron ionisation (EI(+)) mass spectra of the TMS derivatives of carprofen and its metabolites show a diagnostic base peak at M(+)*. -117 corresponding to the loss of COO-Si-(CH(3))(3) group as a radical. GC-MS with positive ion ammonia chemical ionisation (CI(+)) of the compounds provided both derivatised molecular mass and some structural information. Deutromethylation-TMS derivatisation was used to distinguish between aromatic and aliphatic oxidations of carprofen. The drug is rapidly absorbed, extensively metabolised and excreted as phase II conjugates in urine. Carprofen, three aromatic hydroxy and a minor N-hydroxy metabolite were detected for up to 48 h. For samples collected between 2 and 8 h after administration, the concentration of total carprofen ranged between 200 and 490 ng ml(-1). The major metabolite, alpha-hydroxycarprofen was detected for over 72 h and therefore can also be used as a marker for the forensic screening of carprofen in greyhound urine.

Animals↗
PubMed2003

Genome sequence of Chlamydophila caviae (Chlamydia psittaci GPIC): examining the role of niche-specific genes in the evolution of the Chlamydiaceae.

The genome of Chlamydophila caviae (formerly Chlamydia psittaci, GPIC isolate) (1 173 390 nt with a plasmid of 7966 nt) was determined, representing the fourth species with a complete genome sequence from the Chlamydiaceae family of obligate intracellular bacterial pathogens. Of 1009 annotated genes, 798 were conserved in all three other completed Chlamydiaceae genomes. The C.caviae genome contains 68 genes that lack orthologs in any other completed chlamydial genomes, including tryptophan and thiamine biosynthesis determinants and a ribose-phosphate pyrophosphokinase, the product of the prsA gene. Notable amongst these was a novel member of the virulence-associated invasin/intimin family (IIF) of Gram-negative bacteria. Intriguingly, two authentic frameshift mutations in the ORF indicate that this gene is not functional. Many of the unique genes are found in the replication termination region (RTR or plasticity zone), an area of frequent symmetrical inversion events around the replication terminus shown to be a hotspot for genome variation in previous genome sequencing studies. In C.caviae, the RTR includes several loci of particular interest including a large toxin gene and evidence of ancestral insertion(s) of a bacteriophage. This toxin gene, not present in Chlamydia pneumoniae, is a member of the YopT effector family of type III-secreted cysteine proteases. One gene cluster (guaBA-add) in the RTR is much more similar to orthologs in Chlamydia muridarum than those in the phylogenetically closest species C.pneumoniae, suggesting the possibility of horizontal transfer of genes between the rodent-associated Chlamydiae. With most genes observed in the other chlamydial genomes represented, C.caviae provides a good model for the Chlamydiaceae and a point of comparison against the human atherosclerosis-associated C.pneumoniae. This crucial addition to the set of completed Chlamydiaceae genome sequences is enabling dissection of the roles played by niche-specific genes in these important bacterial pathogens.

Adhesins, Bacterial↗
PubMed2003

Calcium supplementation on bone loss in postmenopausal women.

BACKGROUND: Although calcium is one the simplest and least expensive strategies for preventing osteoporotic fractures calcium supplementation is nevertheless not without controversy (Kanis 1989; Nordin 1990). The Food and Drug Administration in the US has permitted a bone health claim for calcium-rich foods, and the NIH in its Consensus Development Process approved a statement that high calcium intake reduces the risk of osteoporosis. OBJECTIVES: To assess the effects of calcium on bone density and fractures in postmenopausal women. SEARCH STRATEGY: We searched Cochrane Controlled Register, MEDLINE and EMBASE up to 2001, and examined citations of relevant articles and proceedings of international meetings. SELECTION CRITERIA: Trials that randomized postmenopausal women to calcium supplementation or usual calcium intake in the diet and reported bone mineral density of the total body, vertebral spine, hip, or forearm or recorded the number of fractures, and followed patients for at least one year were considered for inclusion. DATA COLLECTION AND ANALYSIS: Three independent reviewers assessed the methodologic quality and extracted data for each trial. For each bone density site (lumbar spine, total body, combined hip and combined forearm), we calculated the weighted mean difference in bone density between treatment and control groups using the percentage change from baseline. We constructed regression models in which the independent variables were year and dose, and the dependent variable was the effect size. This regression was used to determine the years across which pooling was appropriate. Heterogeneity was assessed. For each fracture analysis we calculated a risk ratio. MAIN RESULTS: Fifteen trials, representing 1806 participants, were included. Calcium was more effective than placebo in reducing rates of bone loss after two or more years of treatment. The pooled difference in percentage change from baseline was 2.05% (95% CI 0.24 to 3.86) for total body bone density, 1.66% (95% CI 0.92 to 2.39) for the lumbar spine at 2 years, 1.60% (95% CI 0.78 to 2.41) for the hip, and 1.91% (95% CI 0.33 to 3.50) for the distal radius. The relative risk of fractures of the vertebrae was 0.79 (95% CI 0.54 to 1.09); the relative risk for non-vertebral fractures was 0.86 (95% CI 0.43 to 1.72). REVIEWER'S CONCLUSIONS: Calcium supplementation alone has a small positive effect on bone density. The data show a trend toward reduction in vertebral fractures, but it is unclear if calcium reduces the incidence of non vertebral fractures.

Bone Density↗
PubMed2002

Detection of hepatitis C core antigen in serum or plasma as a marker of hepatitis C viraemia in the serological window-phase.

A new immunoassay for the detection of hepatitis C core antigen (HCVcoreAg) in peripheral blood during serological window-phase was evaluated among healthy blood donors, commercially available hepatitis C virus (HCV) seroconversion panels and in-house specimens from individuals undergoing seroconversion. Among 1964 low-risk blood donor samples, seven samples were initially reactive but only one was repeat reactive. Reactivity of this specimen was not confirmable by neutralization with specific anti-HCV core antibody, and the sample was negative for HCV RNA by polymerase chain reaction (PCR). The specificity of the HCVcoreAg enzyme-linked immunosorbent assay (ELISA) was 99.95%. In seven commercially available HCV seroconversion panels, HCVcoreAg appeared 23-46 days earlier than anti-HCV antibody by third generation assay. Additional testing with specimens from patients undergoing anti-HCV seroconversion indicated that HCVcoreAg becomes undetectable by the present test format soon after the onset of antibody. This test may be considered as an alternative to nucleic amplification techniques (NAT) for blood donor HCV screening. Additional development of technology for detecting HCVcoreAg may be useful for patient diagnosis and therapy monitoring.

Blood Donors↗
PubMed2002

Complete genome sequence and comparative analysis of the metabolically versatile Pseudomonas putida KT2440.

Pseudomonas putida is a metabolically versatile saprophytic soil bacterium that has been certified as a biosafety host for the cloning of foreign genes. The bacterium also has considerable potential for biotechnological applications. Sequence analysis of the 6.18 Mb genome of strain KT2440 reveals diverse transport and metabolic systems. Although there is a high level of genome conservation with the pathogenic Pseudomonad Pseudomonas aeruginosa (85% of the predicted coding regions are shared), key virulence factors including exotoxin A and type III secretion systems are absent. Analysis of the genome gives insight into the non-pathogenic nature of P. putida and points to potential new applications in agriculture, biocatalysis, bioremediation and bioplastic production.

Bacterial Proteins↗