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Biomedical subjects

R Thompson

Publications and source records attributed to R Thompson.

At least 37 records · Page 2Linked to original sources
PubMed2004

Pediatric jejunoileitis: a severe Crohn's disease phenotype that requires intensive nutritional management.

BACKGROUND: Jejunoileitis (JI) is an unusual manifestation of Crohn's disease (CD) that has been associated with high morbidity and the frequent need for surgical intervention. Although the disease has been well-described in adults, the true prevalence and clinical phenotype in children is unknown. AIM: To compare the clinical course and nutritional impact of CD in children with and without proximal small bowel involvement. METHODS: Patients with either Crohn's jejunitis or JI with or without colonic involvement were identified through a clinical database (1996--2002). All radiologic studies were reviewed by an experienced radiologist blinded to the clinical diagnosis. Thirty-six patients with CD without histologic or radiologic signs of proximal small bowel involvement were used for comparison. All medical, surgical, and hematologic parameters were compared in both disease groups. RESULTS: Among the 134 patients with CD, 23 (17%) had radiologic signs of JI, including intestinal fold thickening (57%), luminal narrowing (31%), and skip lesions (13%). Enteric fistula (6%) and strictures (6%) were less common. Patients with JI were likely to be stunted at the time of diagnosis, require surgical intervention (P < 0.03) and nutritional therapy in the form of nasogastric tube feeds (P < 0.03). Nutritional therapy was also associated with an improvement in height in patients with proximal small bowel disease (OR:5.87). DISCUSSION: JI is a relatively common disease phenotype in children with CD that requires aggressive nutritional and surgical intervention. Future studies are required to determine if the early detection and use of immune modulators may lessen the morbidity associated with proximal small bowel disease.

Child↗
PubMed2004

Personal characteristics associated with consistency of recall of depressed or anhedonic mood in the 13-year follow-up of the Baltimore Epidemiologic Catchment Area survey.

OBJECTIVE: Our study addressed two primary questions: (1) How reliable is long-term recall of lifetime history of episodes of depressed mood? (2) What characteristics are associated with consistent recall of this history? METHOD: Psychiatric symptoms were assessed in a population-based longitudinal survey of 1498 persons twice, in 1981 and 1994. Respondents whose reports of history of depressed affect were discordant after a 13-year follow-up interval were compared with those whose reports were concordant. RESULTS: Absence of a reported history of episode of depressed mood was more consistently recalled than presence of such an episode. The kappa of reported lifetime history of episode of depressed mood was 0.32. Several personal characteristics predicted consistency of recall. CONCLUSION: If assessment of past episodes of depressed mood is used as guide for identifying cases at risk for depression, account must be taken of the personal factors that might influence recall.

Activities of Daily Living↗
PubMed2004

Strongyloidiasis: challenges in diagnosis and management in non-endemic Kuwait.

Among immunocompromised individuals, hyper-infection with Strongyloides stercoralis may occur and lead to fatal strongyloidiasis. To clinicians and laboratory diagnosticians in non-endemic countries such as Kuwait, this severe infection poses a particular problem. The clinical histories and signs and symptoms of four Kuwaiti cases of S. stercoralis hyper-infection were reviewed. Each of the four was found not only to have lived in an area where S. stercoralis was endemic but also to have been treated with immunosuppressive steroids (for medical problems unrelated to the nematode infection). When they presented with undiagnosed hyper-infections their clinical features were confusing. Three of the cases, all with low eosinophil counts, died but the other, who was treated with thiabendazole, survived. In the light of these observations, healthy medical examinees who had recently moved from endemic zones were checked for asymptomatic S. stercoralis infection, both by stool examination and ELISA-based serology. Of 381 stool samples investigated over a 3-month period, 183 (48%) were found positive for helminths, 7% for S. stercoralis. Of 198 individuals from endemic zones who were screened after another medical examination, 71 (35.8%) were found positive for intestinal helminth parasites, including one (1.45%) infected with S. stercoralis. Although ELISA appear reliable in making a presumptive diagnosis of strongylodiasis, the results of such assays are not very specific and are best interpreted in conjunction with the patient's clinical status. The concurrent administration of anthelminthics to patients prescribed steroids who, because they live or have lived in an area where S. stercoralis is endemic, are at risk of infection with the nematode, should be considered.

Adult↗
PubMed2003

Observations on the swarming and mating behaviour of Anopheles funestus from southern Mozambique.

BACKGROUND: Control of malaria by the release of genetically modified mosquitoes refractory to transmission is now becoming a possibility. In many areas of Africa, Anopheles gambiae is found together with an equally important vector, An. funestus. Given their sympatry and the likelihood of a similar mating period some aspects of the mating behaviour of An. gambiae s.l. and An. funestus are likely to differ. We therefore attempted to characterise the swarming behaviour of An. funestus and to determine if any aspects of the observed behaviour differed from that recorded for the M form of An. gambiae from São Tomé. METHODS: In March - May 2002 the swarming, mating, house exiting and resting behaviour of Anopheles funestus was studied by direct observation in Mozambique. Swarming males and insects in copula were collected by sweep net. Wing lengths of males collected resting, exiting houses, swarming and mating were measured and the wingbeat frequency distribution of individual insects, in free flight confined inside netting covered paper cups, was also determined. RESULTS: Mono-specific swarms occurred at sunset in relatively open areas close to houses used for resting. Mating pairs were seen 11 +/- 3.7 min after the start of swarming. The number of total pairs observed being inversely proportional to the time difference between the start of swarming and the first pairing. The great majority of females mated before feeding. Male or female size did not appear to affect mating success or other behaviours. During the study, ambient temperatures decreased and female, but not male, wing size increased. At 516 Hz, the flight tone of female An. funestus was similar to the 497 Hz of the local An. gambiae. Males dispersed if light or dark artificial horizontal markers were placed underneath naturally occurring swarms. CONCLUSION: Differential response to markers would be sufficient for swarming in An. funestus and An. gambiae s.l. to occur in distinct sites.

Activity Cycles↗
PubMed2002

Comparison of capillary electrophoresis and reversed-phase liquid chromatography for determination of the enantiomeric purity of an M3 antagonist.

The chiral separation of an M3 antagonist was investigated using capillary electrophoresis (CE) with various sulfated cyclodextrins and by reversed-phase liquid chromatography with derivatized cellulose, derivatized amylose, and two protein stationary phases. Operational parameters for each technique, such as the concentration of the chiral selectors, background electrolyte (or mobile phase) pH and type, organic modifiers, injection mode and temperature were varied in order to achieve a desired elution order and to meet a 0.1% limit of quantitation (LOQ) criteria. Based on the advantages and disadvantages of each technique, a practical CE method using sulfated gamma-cyclodextrin was selected. The method was validated in terms of linearity, LOQ, accuracy, ruggedness and precision.

Buffers↗
PubMed2002

The association between diet and chronic obstructive pulmonary disease in subjects selected from general practice.

It is unclear why some smokers develop chronic obstructive pulmonary disease (COPD) whilst the majority do not. Antioxidants found in food may protect against lung tissue injury, but previous epidemiological studies are inconsistent and do not focus on those most at risk of COPD, namely smokers. This case-controlled study measured the difference in dietary intake between smokers and exsmokers with and without COPD. Cases were patients > 45 yrs of age with > 10 pack-yrs of smoking, a forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) of < or = 70% and a FEV1 of < or = 80% of predicted. Controls were patients >45 yrs of age with > 10 pack-yrs of smoking, a FEV1/FVC of > 70% and a FEV1 > 80% pred. Data were collected using validated questionnaires. Logistic regression analysis for an unmatched case-controlled study was performed. After controlling for other independent predictors of COPD, those with vegetable intake of > or = 1 portion x day(-1) (93 g) were less likely to have COPD, as were those consuming > or = 1.5 portions x day(-1) of fruit. This was not due to an overall reduction in food/calorie intake caused by the disease because: 1) adjusting for body mass index did not alter the estimates; 2) the effect was specific to fruit and vegetables, i.e. not other food groups; and 3) the estimates from incident cases were similar. In conclusion, fruit and vegetable consumption is inversely associated with chronic obstructive pulmonary disease and may explain why some smokers do not develop chronic obstructive pulmonary disease.

Adult↗
PubMed2002

Contrasting models for lactation curve analysis.

Several statistical models have been proposed for the genetic evaluation of production traits in dairy cattle based on test-day records. Three main approaches have been put forward in the literature: random regression, orthogonal polynomials, and, more recently, character process models. The aim of this paper is to show how these different approaches are related, to compare their performance for the genetic analysis of lactation curves, and to assess equivalence between sire and animal models for repeated measures analyses. It was found that, with an animal model, a character process model with 11 parameters performed better, regarding the likelihood criterion, than a quartic random regression model (with 31 parameters). However, although the likelihood was higher, the genetic variance was very different with the character process model from the unstructured model, which raises important issues concerning model selection criteria. There are advantages in combining methodologies. A quadratic random regression model for the environmental part, combined with a character process model for the residual, performed better than the quartic random regression model and had fewer parameters. A character process structure allowing for a correlation pattern modeled the residual better than a simple quadratic variance, and had only one extra parameter.

Animals↗
PubMed2002

Heritability, reliability of genetic evaluations and response to selection in proportional hazard models.

The purposes of this study were 1) to investigate the heritability, reliability, and selection response for survival traits following a Weibull frailty proportional hazard model; and 2) to examine the relationship between genetic parameters from a Weibull model, a discrete proportional hazard model, and a binary data analysis using a linear model. Both analytical methods and Monte Carlo simulations were used to achieve these aims. Data were simulated using the Weibull frailty model with two different shapes of the Weibull distribution. Breeding values of 100 unrelated sires with 50 to 100 progeny (with different levels of censoring) were generated from a normal distribution and two different sire variances. For analysis of longevity data on the discrete scale, simulated data were transformed to a discrete scale using arbitrary ends of discrete intervals of 400, 800, or 1200 d. For binary data analysis, an individual's longevity was either 0 (when longevity was less than the end of interval) or 1 (when longevity was equal or greater than the end of interval). Three different statistical models were investigated in this study: a Weibull model, a discrete-time model (a proportional hazard model assuming that the survival data are measured on a discrete scale with few classes), and a linear model based upon binary data. An alternative derivation using basic expressions of reliabilities in sire models suggests a simple equation for the heritability on the original scale (effective heritability) that is not dependent on the Weibull parameters. The predictions of reliabilities using the proposed formulae in this study are in very good agreement with reliabilities observed from simulations. In general, the estimates of reliability from either the discrete model or the binary data analysis were close to estimates from the Weibull model for a given number of uncensored records in this simplified case of a balanced design. Although selection response from the binary data analysis depends on the end of interval point, there is a relatively good agreement between selection responses in the Weibull model and the binary data analysis. In general, when the underlying survival data is from a Weibull distribution, it appears that the method of analyzing data does not greatly affect the results in terms of sire ranking or response to selection, at least for the simplified context considered in this study.

Animals↗
PubMed2001

The ep -->e'p eta reaction at and above the S11(1535) baryon resonance.

New cross sections for the reaction e p-->e p eta are reported for total center of mass energy W = 1.5--1.86 GeV and invariant momentum transfer Q2 = 0.25--1.5 (GeV/c)(2). This large kinematic range allows extraction of important new information about response functions, photocouplings, and eta N coupling strengths of baryon resonances. Newly observed structure at W approximately 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance.

Journal Article↗
PubMed2001

The role of pyridoxal phosphate in the function of EspB, a protein secreted by enteropathogenic Escherichia coli.

The sequence of EspB, a secreted protein required for virulence of enteropathogenic Escherichia coli (EPEC), reveals a motif common to enzymes that bind pyridoxal phosphate. Pyridoxal phosphate was not found by fluorometry in concentrated supernatants of EPEC cultures that contain EspB. Plasmids containing cloned espB, in which the lysine residue conserved in the motif was substituted with either an arginine or methionine residue, remained capable of complementing an espB deletion mutant to restore EspB function. The results of these studies do not support a role for pyridoxal phosphate in EspB function.

Actins↗
PubMed2001

Harm reduction theories and strategies for control of human immunodeficiency virus: a review of the literature.

AIM: To provide a comprehensive review of the literature on harm reduction theories and strategies related primarily to licit and illicit drug use. BACKGROUND: Although human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) disease transmission is well understood, it continues to spread, particularly among injection drug users (IDUs). Despite early indications that HIV would be contained within the IDU community, it is spreading to non-IDU sexual partners and to children of IDUs, threatening a more widespread epidemic. METHODS: An examination of research studies and theoretical writings including reviews and policy papers published in English between 1990 and 2000. RESULTS: Harm reduction does not seek to eliminate drug use; it focuses on minimizing the personal and social harms and costs associated with drug use and spread of HIV. It seeks to ameliorate conditions surrounding drug use responsible for the spread of HIV in the IDU community: unequal access to health services; sharing of infected needles; racial and social discrimination; poverty; exposure to street violence; inadequate housing; lack of employment; poor general or mental health and other demographic and social determinants. Some controversial harm reduction strategies are described: methadone maintenance programmes, illegal drugs dispensing under controlled conditions, needle exchanges, HIV testing, vein maintenance, safe-sex and would-care programmes. CONCLUSION: The main challenge is to get IDUs to protect themselves against HIV when suffering physical and social privations and addiction needs. Diverse perspectives on harm reduction are problematic with consequences for success of drug use initiatives. Practical, ethical and theoretical complexities exist but further research is needed to build support for a harm-reduction orientation in practice and policy formulation.

Community-Institutional Relations↗
PubMed2001

HTLV-1 decreases Th2 type of immune response in patients with strongyloidiasis.

Eosinophils, immunoglobulin (Ig)E and cytokines have important roles in defence mechanisms against helminths. In this study, the influence of HTLV-1 infection, characterized by a Th1 type of immune response, was evaluated on the cytokine pattern and parasitic specific IgE response in patients with strongyloidiasis. Patients were divided into four groups: strongyloidiasis without HTLV-1 infection, strongyloidiasis with HTLV-1, HTLV-1 without strongyloidiasis and controls without either helminth infection or HTLV-1. The cytokine profile was determined in supernatants of mononuclear cells stimulated with Strongyloides stercoralis crude antigen and the parasite specific IgE was measured by ELISA. Patients coinfected with HTLV-1 had higher levels of interferon (IFN)-gamma and interleukin (IL)-10 (P < 0.05) and lower levels of IL-5 and IgE (P < 0.05) than patients with strongyloidiasis without HTLV-1. There was an inverse relationship between IFN-gamma and IL-5 (P = 0.01; rs = - 0.37) and between IFN-gamma and parasite specific IgE (P = 0.01; rs = - 0.39), and a direct relationship between IFN-gamma and IL-10 (P = 0.04; rs = 0.35). These data show that coinfection with HTLV-1 decreases IL-5 and IgE responses in patients with strongyloidiasis consistent with a relative switch from Th2 to Th1 response. Immunological responses such as these are important in the control of this helminthic infection.

Adult↗
PubMed2001

BSEP: function and role in progressive familial intrahepatic cholestasis.

Secretion of bile acids is the major driving force for bile flow in mammals. The recently described adenosine triphosphate (ATP)-dependent bile acid transporter, bile salt export pump (BSEP), formerly called sister of p-glycoprotein, is responsible for active transport of bile acids across the hepatocyte canalicular membrane into bile. It is now recognized that mutations in the gene encoding this protein (ABCB11) are responsible for a subgroup of infants and children with progressive familial cholestasis (PFIC-2), a cholestatic disorder causing extreme pruritus, growth failure, and progression to cirrhosis in the first decade of life. Understanding the structure and function of BSEP has improved our understanding of the mechanisms underlying bile secretion. Determining genotype/phenotype relationships in patients with mutations in this gene are currently ongoing.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Neuropsychologic performance in school-aged children with sickle cell disease: a report from the Cooperative Study of Sickle Cell Disease.

OBJECTIVES: To compare the results of serial neuropsychologic testing in children with sickle cell disease with the results of serial magnetic resonance imaging (MRI) examinations, particularly to evaluate neuropsychologic function in the absence of overt stroke. STUDY DESIGN: In the Cooperative Study of Sickle Cell Disease, serial neuropsychologic and MRI tests were performed in 373 patients (255 with hemoglobin SS and 118 with hemoglobin SC), 6 to 18 years of age. MRI of the brain and a neuropsychologic battery that included the Wechsler Intelligence Scale for Children (WISC-R or WISC-III) and the Woodcock-Johnson Math and Reading Achievement Tests were performed concurrently and repeated every 2 to 3 years. A silent infarct was defined as an MRI finding of increased signal intensity on T(2) imaging in a patient without a history of stroke. RESULTS: Twenty-seven patients, all with hemoglobin SS, had overt strokes and 62 had silent infarcts (52 with hemoglobin SS). Patients with hemoglobin SS and silent infarcts had significantly lower scores for math and reading achievement, Full-Scale IQ, Verbal IQ, and Performance IQ, when compared with those with normal MRI findings. In children with hemoglobin SS and normal MRI findings, the scores for Verbal IQ, math achievement, and coding (a subscale of Performance IQ) declined with increasing age. CONCLUSIONS: School-aged children with sickle cell disease had compromised neuropsychologic function in the presence of silent infarcts. In addition, they had declines in performance in certain areas of function over time. Therapeutic interventions that prevent or lessen cognitive impairment are needed before school entry for children with sickle cell disease.

Anemia, Sickle Cell↗