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Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 37 records · Page 2Linked to original sources
PubMed2000

Louisiana Parish Health Profiles 1999: using information to drive local action.

The Parish Health Profiles 1999, published by the Department of Health and Hospitals Office of Public Health (OPH), are intended to be a source of parish-level health information to be used for community-level planning. The third edition of the Profiles uses a broader definition of health to understand the quality of life of communities. The included information represents not only health status, but also other aspects of quality of life, such as the status of local education, economy, environment, and crime and safety. The process of collecting this information yielded two additional results: strengthened relationships amongst information-providing agencies across the state and an orientation and subsequent comprehensive chapter of information on action and resources. In addition, the publication is designed to be reader friendly, with a strong emphasis on the use of the Parish Health Profiles to aid in understanding data. The Office of Public Health recognizes that the Parish Health Profiles will continue to evolve to meet the needs of their audience. In order to ensure continuous quality improvement through future editions, the Profiles are supported by an 18-month, multi-level evaluation process, ensuring consumer and user input and comment at different levels.

Community Networks↗
PubMed1999

The efficacy of exercise as an aid for smoking cessation in women: a randomized controlled trial.

BACKGROUND: Smoking prevalence rates among women are declining at a slower rate than among men. OBJECTIVE: To determine if exercise, a healthful alternative to smoking, enhances the achievement and maintenance of smoking cessation. METHODS: Two hundred eighty-one healthy, sedentary female smokers were randomly assigned to either a cognitive-behavioral smoking cessation program with vigorous exercise (exercise) or to the same program with equal staff contact time (control). Subjects participated in a 12-session, group-based smoking cessation program. Additionally, exercise subjects were required to attend 3 supervised exercise sessions per week and control subjects were required to participate in 3 supervised health education lectures per week. Abstinence from smoking was based on self-report, was verified by saliva cotinine level, and was measured at 1 week after quit day (week 5), end of treatment (week 12), and 3 and 12 months later (20 and 60 weeks after quit day, respectively). RESULTS: Compared with control subjects (n = 147), exercise subjects (n = 134) achieved significantly higher levels of continuous abstinence at the end of treatment (19.4% vs 10.2%, P = .03) and 3 months (16.4% vs 8.2%, P=.03) and 12 months (11.9% vs 5.4%, P=.05) following treatment. Exercise subjects had significantly increased functional capacity (estimated VO2 peak, 25+/-6 to 28+/-6, P<.01) and had gained less weight by the end of treatment (3.05 vs 5.40 kg, P = .03). CONCLUSIONS: Vigorous exercise facilitates short- and longer-term smoking cessation in women when combined with a cognitive-behavioral smoking cessation program. Vigorous exercise improves exercise capacity and delays weight gain following smoking cessation.

Adult↗
PubMed1999

The selection and suppression of action: ERP correlates of executive control in humans.

A key aspect of higher cortical function is the ability to selectively withhold or suppress action where appropriate. To examine the time course of executive control we used dense-sensor EEG recording techniques to study event-related electrical potentials (ERPs) during a visual 'go/no-go' task. We show that during both go and no-go trials there is a positive deflection in the ERP, which develops over posterior parietal sensors approximately 350 ms (P300) after the onset of a conditional visual stimulus, but is selectively suppressed during no-go trials. We also show that this modulation of the parietal P300 is preceded by a negative deflection in the ERP recorded over frontal cortex (N2), which is apparent only for no-go trials. We suggest that this signal provides an electrophysiological marker in man for the decision to withhold the execution of a motor response.

Adult↗
PubMed1999

Familial patterns of thoracic aortic aneurysms.

HYPOTHESIS: To provide evidence that genetic factors contribute to the development of thoracic aortic aneurysms (TAA) by demonstrating familial patterns of the disease. DESIGN: Retrospective review. SETTING: University hospital. PATIENTS AND METHODS: We sought to identify familial patterns of TAA from a database of 598 patients evaluated or treated for TAA at the Yale Center for Thoracic Aortic Disease, New Haven, Conn, from January 1985 to August 1998. Of the 598 patients, 45 patients had a diagnosis of Marfan syndrome and 553 patients had no known history of any collagen vascular disorder. Of the 553 patients in the latter category, 398 patients had confirmed TAA, 66 had TAA with concomitant aortic dissections, and 89 had aortic dissections. From the group of 464 patients with TAA with or without concomitant aortic dissections, 2 interviewers attempted to contact 150 randomly selected patients for telephone screening to determine the presence of familial patterns of aortic disease. Fifteen of these patients were lost to follow-up. Complete medical and family histories of the remaining 135 patients (85 men, 50 women) were reviewed. Of the 135 individuals screened, 26 (18 men, 8 women) (19.3%) were found to belong to multiplex pedigrees. These 26 patients with familial nonsyndromic TAA were compared with the remaining 109 patients with sporadic TAA and the 45 patients with Marfan syndrome-associated TAA. MAIN OUTCOME MEASURES: Groups were examined for statistical differences in age and aortic size at the time of diagnosis, growth rates of TAA, and rates of concomitant diseases. Nonsyndromic family pedigrees were analyzed and potential modes of inheritance were determined. RESULTS: The mean age at presentation for patients with familial nonsyndromic TAA (56.8 years) was significantly younger than the mean age of presentation in sporadic cases (64.3 years, P< or =.03), and significantly older than that of patients with Marfan syndrome (24.8 years, P< or =.001). Patients with a family history of aortic aneurysms had faster growth rates (0.22 cm/y) compared with patients with sporadic TAA (0.03 cm/y) (P< or =.001) and patients with Marfan syndrome (0.10 cm/y) (P< or =.04). Familial nonsyndromic TAA in patients with a concomitant aortic dissection had a growth rate of 0.33 cm/y, which was greater than that of patients with sporadic TAA (0.10 cm/y) and patients with Marfan syndrome (0.08 cm/y) with associated aortic dissection. This growth of 0.33 cm/y was significantly faster than the overall growth rate estimate of aneurysms in patients with aortic dissection (0.14 cm/y) (P< or =.05). Ten pedigrees (38.5%) showed direct father to son transmission, consistent with an autosomal dominant mode of inheritance. Six family pedigrees (23.1%) suggested an autosomal dominant or X-linked mode of inheritance. Seven pedigrees (26.9%) suggested a recessive mode of inheritance; 2 an autosomal recessive mode, and 5 an X-linked recessive or autosomal recessive mode. The remaining 3 pedigrees displayed more complex modes of inheritance. CONCLUSIONS: This study supports the role of genetic factors influencing familial aggregation of TAA. Thoracic aortic aneurysms in association with multiplex pedigrees represent a new risk factor for aneurysm growth. Pedigree analysis suggests genetic heterogeneity. The primary mode of inheritance seems to be autosomal dominant, but X-linked dominant and recessive modes are also evident.

Adolescent↗
PubMed1999

Maternal function of a retroviral-type zinc-finger protein is essential for Drosophila development.

Previous studies have shown that zygotic expression of the Drosophila lark gene, which encodes an RNA-binding protein, is essential for embryogenesis. We now show that lark mRNA is abundant in preblastoderm (0-2 h) embryos, prior to zygotic transcription, indicative of maternal inheritance. Lark can also be detected within the nurse cells of developing egg chambers, suggesting a function for the protein during oogenesis. To test the hypothesis that the maternal inheritance of lark is required for oogenesis or early development, we employed the "FLP-DFS" technique to eliminate the lark maternal component within the germ line. Unfertilized and fertilized eggs lacking the lark maternal component exhibit a "fragile" phenotype, indicating that the protein functions during oogenesis. Furthermore, differentiation of the fertilized eggs is abnormal-most embryos arrest prior to blastoderm formation and exhibit morphological phenotypes that might reflect underlying defects in syncytial nuclear cycling or cellularization. Mutational analysis of a retroviral-type zinc finger within the lark protein indicates that it is required for the maternal function of the protein: females are completely sterile when their only source of lark protein contains a zinc-finger mutation. The aggregate of our studies shows that the germ-line expression of lark is essential for development, and suggests that the retroviral-type zinc finger mediates important RNA-binding functions during oogenesis and/or early development.

Animals↗
PubMed1999

A prospective randomized trial of complete atrioventricular transplantation versus ventricular transplantation with atrioplasty.

BACKGROUND: The standard technique of ventricular transplantation with atrioplasty (SOHT) distorts atrial anatomy. This may compromise diastolic ventricular function, impair atrioventricular valve competence and elevate resting ANP secretion. In contrast, complete atrioventricular anastomosis (CAVT) preserves atrial geometry. METHODS: We evaluated long term outcome in a prospective randomized trial of CAVT vs. SOHT. The primary outcome measures were peak oxygen uptake, atrioventricular valve regurgitation and ANP secretion. RESULTS: 58 recipients (median age 49 years; range 21-64) were consecutively randomized (29 CAVT; 29 SOHT). There were no differences in total ischaemic time, cardiopulmonary bypass time, postoperative bleeding or immunosuppression. Cardiopulmonary exercise tolerance testing was performed by 29 recipients at 742 to 1825 days. Pulmonary function was equivalent. Peak oxygen consumption expressed as a percentage of predicted maximum was 53.5% with CAVT and 63.8% with SOHT (p = 0.14). Echocardiography was performed on 41 recipients at 944 to 1665 days. There was less tricuspid regurgitation with CAVT (3/22 [13.6%] CAVT vs. 10/19 [52.6%] SOHT; p = 0.019). The incidence of mitral regurgitation was similar (5/22 [22.7%] CAVT vs. 4/19 [21.1%] SOHT; p = 0.803). Resting ANP secretion was assessed in 17 recipients at 1013 to 1812 days. All were hemodynamically stable and none had concurrent rejection. Resting ANP secretion was less with CAVT (CAVT: 283 pg/ml; SOHT: 521.4; p = 0.041). CONCLUSIONS: Peak oxygen consumption was not influenced by implantation technique. However, CAVT reduced the incidence of tricuspid regurgitation and attenuated the elevation in resting ANP secretion.

Adult↗
PubMed1999

Cellular immune responses of a Senegalese community recently exposed to Schistosoma mansoni: correlations of infection level with age and inflammatory cytokine production by soluble egg antigen-specific cells.

A recently reported epidemic of Schistosoma mansoni infection in Senegal provided an opportunity to study the dynamics of the development of immunity to human schistosomiasis. We report here on the cell-mediated immune response in a population of 99 females and 95 males, with particular emphasis on the relationship between intensity of infection and age. We found that the intensity of infection correlated negatively with age in females but not in males. In men and women, both Th1- and Th2-type cytokines were detected upon in vitro stimulation of PBMCs with soluble egg antigen (SEA) or soluble adult worm antigens (SWAP). In the female group, SEA-induced PBMC proliferation was associated with the production of IFN-gamma, IL-2 and IL-5, all of which correlated negatively with intensity of infection. Most cytokine production correlated positively with age. Spontaneous production of TNF-alpha, IL-6 and IL-10 was higher in the infected population than in an uninfected control group. Our results suggest that immunity to infection could be more pronounced in the female population and associated with a Th0/1 + 2 pattern of cytokine secretion mediated by soluble egg antigen (SEA).

Adolescent↗
PubMed1999

Ferrioxamine-mediated Iron(III) utilization by Salmonella enterica.

Utilization of ferrioxamines as sole sources of iron distinguishes Salmonella enterica serotypes Typhimurium and Enteritidis from a number of related species, including Escherichia coli. Ferrioxamine supplements have therefore been used in preenrichment and selection media to increase the bacterial growth rate while selectivity is maintained. We characterized the determinants involved in utilization of ferrioxamines B, E, and G by S. enterica serotype Typhimurium by performing siderophore cross-feeding bioassays. Transport of all three ferric siderophores across the outer membrane was dependent on the FoxA receptor encoded by the Fur-repressible foxA gene. However, only the transport of ferrioxamine G was dependent on the energy-transducing protein TonB, since growth stimulation of a tonB strain by ferrioxamines B and E was observed, albeit at lower efficiencies than in the parental strain. Transport across the inner membrane was dependent on the periplasmic binding protein-dependent ABC transporter complex comprising FhuBCD, as has been reported for other hydroxamate siderophores of enteric bacteria. The distribution of the foxA gene in the genus Salmonella, as indicated by DNA hybridization studies and correlated with the ability to utilize ferrioxamine E, was restricted to subspecies I, II, and IIIb, and this gene was absent from subspecies IIIa, IV, VI, and VII (formerly subspecies IV) and Salmonella bongori (formerly subspecies V). S. enterica serotype Typhimurium mutants with either a transposon insertion or a defined nonpolar frameshift (+2) mutation in the foxA gene were not able to utilize any of the three ferrioxamines tested. A strain carrying the nonpolar foxA mutation exhibited a significantly reduced ability to colonize rabbit ileal loops compared to the foxA+ parent. In addition, a foxA mutant was markedly attenuated in mice inoculated by either the intragastric or intravenous route. Mice inoculated with the foxA mutant were protected against subsequent challenge by the foxA+ parent strain.

Amino Acid Sequence↗
PubMed1999

Bordetella bronchiseptica-mediated cytotoxicity to macrophages is dependent on bvg-regulated factors, including pertactin.

The effect of Bordetella bronchiseptica infection on the viability of murine macrophage-like cells and on primary porcine alveolar macrophages was investigated. The bacterium was shown to be cytotoxic for both cell types, particularly where tight cell-to-cell contacts were established. In addition, bvg mutants were poorly cytotoxic for the eukaryotic cells, while a prn mutant was significantly less toxic than wild-type bacteria. B. bronchiseptica-mediated cytotoxicity was inhibited in the presence of cytochalasin D or cycloheximide, an inhibitor of microfilament-dependent phagocytosis or de novo eukaryotic protein synthesis, respectively. The mechanism of eukaryotic cell death was examined, and cell death was found to occur primarily through a necrotic pathway, although a small proportion of the population underwent apoptosis.

Adhesins, Bacterial↗
PubMed1999

The alternative sigma factor, sigmaE, is critically important for the virulence of Salmonella typhimurium.

In Escherichia coli, extracytoplasmic stress is partially controlled by the alternative sigma factor, RpoE (sigmaE). In response to environmental stress or alteration in the protein content of the cell envelope, sigmaE upregulates the expression of a number of genes, including htrA. It has been shown that htrA is required for intramacrophage survival and virulence in Salmonella typhimurium. To investigate whether sigmaE-regulated genes other than htrA are involved in salmonella virulence, we inactivated the rpoE gene of S. typhimurium SL1344 by allelic exchange and compared the phenotype of the mutant (GVB311) in vitro and in vivo with its parent and an isogenic htrA mutant (BRD915). Unlike E. coli, sigmaE is not required for the growth and survival of S. typhimurium at high temperatures. However, GVB311 did display a defect in its ability to utilize carbon sources other than glucose. GVB311 was more sensitive to hydrogen peroxide, superoxide, and antimicrobial peptides than SL1344 and BRD915. Although able to invade both macrophage and epithelial cell lines normally, the rpoE mutant was defective in its ability to survive and proliferate in both cell lines. The effect of the rpoE mutation on the intracellular behavior of S. typhimurium was greater than that of the htrA mutation. Both GVB311 and BRD915 were highly attenuated in mice. Neither strain was able to kill mice via the oral route, and the 50% lethal dose (LD50) for both strains via the intravenous (i.v.) route was very high. The i.v. LD50s for SL1344, BRD915, and GVB311 were <10, 5.5 x 10(5), and 1.24 x 10(7) CFU, respectively. Growth in murine tissues after oral and i.v. inoculation was impaired for both the htrA and rpoE mutant, with the latter mutant being more severely affected. Neither mutant was able to translocate successfully from the Peyer's patches to other organs after oral infection or to proliferate in the liver and spleen after i.v. inoculation. However, the htrA mutant efficiently colonized the livers and spleens of mice infected i.v., but the rpoE mutant did not. Previous studies have shown that salmonella htrA mutants are excellent live vaccines. In contrast, oral immunization of mice with GVB311 was unable to protect any of the mice from oral challenge with SL1344. Furthermore, i.v. immunization with a large dose ( approximately 10(6) CFU) of GVB311 protected less than half of the orally challenged mice. Thus, our results indicate that genes in the sigmaE regulon other than htrA play a critical role in the virulence and immunogenicity of S. typhimurium.

Animals↗
PubMed1999

Prior immunity to homologous and heterologous Salmonella serotypes suppresses local and systemic anti-fragment C antibody responses and protection from tetanus toxin in mice immunized with Salmonella strains expressing fragment C.

We have investigated the effect of preexisting immunity to homologous (Salmonella typhimurium) or heterologous (S. dublin) serotypes of Salmonella on the ability of an attenuated S. typhimurium aroA aroD vector (BRD509) to immunize mice against the heterologous antigen fragment C (FrgC). We studied two strains, BRD847 and BRD937, expressing FrgC carried on plasmids that differ only with respect to the promoter controlling FrgC expression, the nirB promoter in the case of BRD847 and the htrA promoter in the case of BRD937. Mice were preimmunized orally with S. typhimurium BRD509, S. dublin aroA aroD (BRD620), or saline. Forty-four days later, they were immunized orally with BRD847 or BRD937. Prior immunity to S. typhimurium severely depressed the serum immunoglobulin G (IgG) and IgA anti-FrgC response in both BRD847- and BRD937-immunized mice. Mice with existing immunity to S. dublin also had lower IgG anti-FrgC geometric mean titers (GMTs) than did mice preimmunized with saline, but this difference was significant only in the case of mice immunized with BRD937. However, in nonimmune mice or in mice preimmunized with S. typhimurium or S. dublin, the anti-FrgC IgG GMTs were always higher in mice in the BRD937 groups than in the equivalent BRD847 groups. This is reflected in the effect of prior immunity on the ability of oral immunization with BRD847 or BRD937 to protect mice from challenge with a lethal dose of tetanus toxin. All of the mice preimmunized with saline and then immunized with BRD847 or BRD937 survived challenge. Only 20% of the animals immunized with BRD847 and 60% of the mice in the BRD937 group survived tetanus toxin challenge if they were preimmunized with BRD509. Preexisting immunity to S. dublin did not affect the ability of BRD937 to immunize mice against tetanus, but it did reduce the efficiency of BRD847: only 60% percent of the mice survived challenge. The intestinal secretory IgA responses to FrgC were very similar in the BRD847 and BRD937 groups. Prior immunity did depress the IgA anti-FrgC titers but only significantly so in the mice preimmunized with BRD509. These results show that preexisting Salmonella immunity, particularly to homologous serotypes, can severely compromise the ability of live Salmonella vectors to deliver heterologous antigens to the mammalian immune system. However, the results also indicate that this may be overcome by the design of more powerful in vivo expression systems.

Animals↗
PubMed1999

The association between the antiphospholipid antibody syndrome and neuropsychological impairment in SLE.

OBJECTIVE: To examine the relationship between neuropsychological impairment and antiphospholipid antibody syndrome (aPL syndrome) in patients with systemic lupus erythermatosus (SLE). PATIENTS: Sixty-nine patients satisfying ACR criteria were studied. Sixteen patients with the aPL syndrome and 53 patients without the syndrome were subjected to eight neuropsychological tests, a physical examination and serological investigations. No patients with other pathology, known to cause acute or chronic impairment of neuropsychological function, were included. Sixty-five underwent MRI scans. RESULTS: There were no significant differences in age, level of education, incidence of hypertension or disease activity in the two groups. Pearson's correlation coefficients revealed a significant negative correlation with duration of disease in six out of eight tests in the aPL positive group and one out of eight in the aPL negative group. This suggests that aPL syndrome may be involved in the psychological impairment in SLE patients. A larger cohort needs to be studied to confirm this observation.

Adolescent↗
PubMed1999

Therapeutic paralysis of critically ill trauma patients: perceptions of patients and their family members.

BACKGROUND: Neuromuscular blocking agents are used in critically ill patients to induce therapeutic paralysis. These drugs leave patients fully immobile but conscious. Analgesics and sedatives are concomitantly administered with the paralytic agents. Little is known about what patients remember when they receive these combinations of drugs. Even less is known about the experiences and needs of the patients' family members during the patients' paralysis. OBJECTIVES: To obtain recollections of therapeutic paralysis in critically ill adult trauma patients and to determine the psychological, emotional, and educational needs of the patients' family members during the time the patients were paralyzed. METHODS: A qualitative phenomenological approach was used to investigate the "lived" experience of therapeutic paralysis of 11 pairs of subjects. Each pair consisted of one critically ill adult trauma patient and one member of the patient's family. RESULTS: The patients recalled their experience of therapeutic paralysis with vagueness, as if they had been dreaming. Few recalled pain or painful procedures. Patients remembered having nurses and family members provide emotional support and encouragement. Family members understood the rationale for use of the drugs. They remembered being encouraged to touch and talk with patients. The subjects suggested providing additional education about events that occur when paralysis is being reversed. CONCLUSIONS: Two confounding variables may have affected these findings: a liberalized visiting policy and use of effective pain and sedation protocols. Healthcare professionals and patients' family members should monitor bedside conversations and use touch and words of encouragement to support patients during therapeutic paralysis.

Adaptation, Psychological↗
PubMed1998

Effect of smoking cessation on exercise performance in female smokers participating in exercise training.

We evaluated in a randomized prospective trial the possible effect of smoking cessation on exercise performance in middle-aged female smokers who underwent vigorous exercise training as an adjunct to a cognitive-behavioral smoking cessation treatment program. A total of 109 subjects met the criteria for this substudy; of these, 51 were in the contact control (nonexercising) group and 58 were in the exercise training group. Both groups had a graded maximal exercise stress test performed on a bicycle ergometer before and after 12 weeks of treatment. All subjects participated in a 12-session, group-based, cognitive-behavioral treatment program for nicotine dependence. Subjects in the contact condition participated in 3 supervised health education lectures per week but did not engage in regular exercise. Subjects in the exercise group trained 3 times a week, averaging 83% of maximum heart rate achieved on their baseline exercise test. On the 12-week exercise stress test, the exercise group did significantly better than control in all aspects of exercise performance. Those who quit showed a further increase in their exercise test duration (p <0.001) and had a greater increase in calculated peak oxygen consumption expressed as fat-free weight (p = 0.031). In conclusion, women who undergo a vigorous exercise training program and quit smoking demonstrate improved exercise performance over those who continue to smoke.

Adult↗
PubMed1998

Routine protein energy supplementation in adults: systematic review.

OBJECTIVES: To determine whether routine oral and enteral nutritional supplementation can improve the weight, anthropometry, and survival of adult patients. DESIGN: Systematic review of randomised controlled trials of oral or enteral protein supplementation in adults. Trials were identified from Medline (Silver Platter 3.11, 1966-96), reference lists of identified studies and review articles, and communication with feed manufacturers. SUBJECTS: Randomised controlled trials comparing oral or enteral protein supplementation with no routine supplementation. All trials of adult subjects were included except those addressing nutrition in pregnancy. MAIN OUTCOME MEASURES: Change in body weight and anthropometry (mid-arm muscle circumference), and all cause case fatality recorded at the end of scheduled follow up. Body weight and anthropometry were analysed as the weighted mean difference and 95% confidence intervals of the percentage change in these variables. Case fatality was analysed with odds ratio and 95% confidence intervals. RESULTS: 32 eligible reports (2286 randomised patients) published between February 1979 and July 1996 were identified, of which 30 (93.8%) (2062 randomised patients) reported outcomes of interest. Case fatality data were available for 1670 (81%) patients, and continuous variable data for up to 1607 (78%) patients. The treatment group receiving routine nutritional supplementation showed consistently improved changes in body weight and anthropometry compared with controls; weighted mean difference 2.06% (95% confidence interval 1.63% to 2.49%) and 3.16% (2.43% to 3.89%) respectively. The pooled odds ratio for death in the treatment group was 0.66 (0.48 to 0.91, 2P<0.01). Apparent benefits were observed in several prespecified subgroups of patients, treatment settings, and interventions, but were not evident if trials with less robust methodology were excluded. CONCLUSIONS: Routine oral or enteral supplementation seems to improve the nutritional indices of adult patients, but there are insufficient data in trials which meet strict methodological criteria to be certain if mortality is reduced. Benefits were not restricted to particular patient groups. Further large pragmatic randomised controlled trials of routine nutritional supplementation are justified.

Administration, Oral↗