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Biomedical subjects

J Tuttle

Publications and source records attributed to J Tuttle.

At least 19 recordsLinked to original sources
PubMed2003

Reduced perivascular PO2 increases nitric oxide release from endothelial cells.

Many studies have suggested that endothelial cells can act as "oxygen sensors" to large reductions in oxygen availability by increasing nitric oxide (NO) production. This study determined whether small reductions in oxygen availability enhanced NO production from in vivo intestinal arterioles, venules, and parenchymal cells. In vivo measurements of perivascular NO concentration ([NO]) were made with NO-sensitive microelectrodes during normoxic and reduced oxygen availability. During normoxia, intestinal first-order arteriolar [NO] was 397 +/- 26 nM (n = 5), paired venular [NO] was 298 +/- 34 nM (n = 5), and parenchymal cell [NO] was 138 +/- 36 nM (n = 3). During reduced oxygen availability, arteriolar and venular [NO] significantly increased to 695 +/- 79 nM (n = 5) and 534 +/- 66 nM (n = 5), respectively, whereas parenchymal [NO] remained unchanged at 144 +/- 34 nM (n = 4). During reduced oxygenation, arteriolar and venular diameters increased by 15 +/- 3% and 14 +/- 5%, respectively: NG-nitro-L-arginine methyl ester strongly suppressed the dilation to lower periarteriolar Po2. Micropipette injection of a CO2 embolus into arterioles significantly attenuated arteriolar dilation and suppressed NO release in response to reduced oxygen availability. These results indicated that in rat intestine, reduced oxygen availability increased both arteriolar and venular NO and that the main site of NO release under these conditions was from endothelial cells.

Adenosine↗
PubMed2000

Family connectedness and women's sexual risk behaviors: implications for the prevention/intervention of STD/HIV infection.

The present study explores the relationship between connectedness with the intergenerational family and women's sexual risk-taking as a guide to the development of family-focused prevention and intervention. Cross-sectional interview data from a pilot study were analyzed for correlations between a number of self-reported, risky sexual practices, the range of extended family members with whom the respondent was in contact, and awareness of stories pertaining to intergenerational family history. Structured interviews were administered by female interviewers to 56 women from two contexts: a STD (sexually transmitted disease) Clinic (N = 26), and an inner-city, Hispanic Community Organization (N = 30). Knowledge of stories about grandparents or great-grandparents was a robust predictor of lower sexual risk-taking in the STD Clinic sample. This relationship persisted, but only at the trend level in the Community Organization sample. In both the total sample and the STD subsample, the number of categories of extended family members with whom a respondent was in at least monthly contact was correlated with less sexual risk-taking. Given the fundamental importance of the family system as the primary social unit, these findings argue for further family theory-based research and for its potential application in the development of health prevention and intervention. Implications for practice and future research are discussed.

Cross-Sectional Studies↗
PubMed1999

Lessons from a large outbreak of Escherichia coli O157:H7 infections: insights into the infectious dose and method of widespread contamination of hamburger patties.

Between November 1992 and February 1993, a large outbreak of Escherichia coli O157:H7 infections occurred in the western USA and was associated with eating ground beef patties at restaurants of one fast-food chain. Restaurants that were epidemiologically linked with cases served patties produced on two consecutive dates; cultures of recalled ground beef patties produced on those dates yielded E. coli O157:H7 strains indistinguishable from those isolated from patients, confirming the vehicle of illness. Seventy-six ground beef patty samples were cultured quantitatively for E. coli O157:H7. The median most probable number of organisms was 1.5 per gram (range, < 0.3-15) or 67.5 organisms per patty (range, < 13.5-675). Correlation of the presence of E. coli O157:H7 with other bacterial indicators yielded a significant association between coliform count and the presence of E. coli O157:H7 (P = 0.04). A meat traceback to investigate possible sources of contamination revealed cattle were probably initially colonized with E. coli O157:H7, and that their slaughter caused surface contamination of meat, which once combined with meat from other sources, resulted in a large number of contaminated ground beef patties. Microbiological testing of meat from lots consumed by persons who became ill was suggestive of an infectious dose for E. coli O157:H7 of fewer than 700 organisms. These findings present a strong argument for enforcing zero tolerance for this organism in processed food and for markedly decreasing contamination of raw ground beef. Process controls that incorporate microbiological testing of meat may assist these efforts.

Animals↗
PubMed1999

Peer education project with persons who have experienced homelessness.

This paper describes an unconventional health education project implemented by nurse practitioners in a nurse-managed clinic serving persons who are homeless. The nurse practitioners perceived that there were a number of potential barriers to providing health education to the homeless patients. These barriers included the fact that this patient population is part of a marginalized subculture affected by a variety of overwhelming social problems. An additional barrier was that the nurses often differed from their homeless patients in terms of race, gender, socioeconomic status, formal education, culture, and life experience. The nurse practitioners designed the Peer Health Education Project (PHEP) to try to overcome some of these barriers. The purpose of the PHEP was to increase the health education knowledge and empowerment of persons who had experienced homelessness so that they could serve as peer health educators with others who were living on the streets. The project model was based on the philosophy of Paulo Freire (1973). The peer health educators served as both leaders and participants in each education session. The educators set the agenda and the nurses acted as facilitators. The project was successful in preparing peer educators. Other indicators of the success of the project included increased empowerment, self-esteem, dignity, hope self-confidence, and community participation of the peer educators.

Adult↗
PubMed1999

Clinical efficacy and safety of tolterodine compared to placebo in detrusor overactivity.

PURPOSE: We evaluated the efficacy, patient acceptability and side effect profile of tolterodine, a new antimuscarinic agent for treating bladder overactivity. MATERIALS AND METHODS: In our randomized, placebo controlled, parallel group study 123, 129 and 64 patients 18 years old or older with proved detrusor overactivity (idiopathic detrusor instability or detrusor hyperreflexia) were randomized to receive 1 or 2 mg. tolterodine, or placebo, respectively, twice daily for 12 weeks. Main outcome measures were number of voids per 24 hours, urine volume per void and episodes of urge incontinence per 24 hours on a frequency-volume chart with detailed recording of side effects. RESULTS: After 12 weeks of treatment mean number of voids per 24 hours plus or minus standard deviation decreased from 11.2 +/- 3.1 to 9.0 +/- 2.6 with the 2 mg. dosage (p = 0.0045 versus placebo). At this dose mean urine volume per void increased from 155 +/- 52 to 190 +/- 70 ml. (p <0.0001 versus placebo), while mean number of incontinence episodes per 24 hours decreased from 3.6 +/- 4.0 to 1.8 +/- 3.1 (p = 0.19 versus placebo). Similar efficacy was observed in patients receiving the 1 mg. dose. Severe dry mouth was reported by only 2, 1 and 2% of patients given the 1 and 2 mg. dose, and placebo, respectively. There was no clinical or electrocardiographic evidence of significant cardiac adverse events. CONCLUSIONS: Tolterodine administration resulted in a significant decrease in the frequency of voiding and improved voided volume but it was seldom associated with troublesome or severe side effects.

Adult↗
PubMed1998

Results of a multicenter trial of the CapSure (Re/Stor) Continence shield on women with stress urinary incontinence.

OBJECTIVES: To prospectively study the impact of the CapSure (Re/Stor) Continence shield for the treatment of stress urinary incontinence. METHODS: One hundred women with pure stress urinary incontinence were enrolled in a 6-month study. Objective measures of urine loss included pad weight test (PdWt) and provocative stress test (PST). Subjective measures included incontinence diaries documenting the number of incontinence episodes per day (IEPD), quality of life questionnaires, and satisfaction surveys. Objective and subjective measures were performed prior to enrollment, during use of the CapSure shield, and after discontinuation of the device. RESULTS: During the 12-week device utilization period, PdWt measurements demonstrated a 96% reduction in urine loss by week 1 and 97% by week 12. Eighty-two percent of subjects were completely dry by week 12. PST demonstrated 100% reduction in urine loss at each visit, with 91% of subjects completely dry by week 12. IEPD also demonstrated a 91% reduction in incontinence episodes by week 12. Quality of life scores and patient satisfaction surveys demonstrated significant improvement. During the 6-week post device utilization period (PUP), subjects continued to demonstrate a reduction in urine loss compared to pre-enrollment data, despite discontinuation of use. PdWt measurements demonstrated a 73% and 79% reduction in urine loss at weeks 14 and 18, respectively. Measurements of PST and IEPD demonstrated significant reductions in urine loss at weeks 14 and 18. A 1.5% prevalence of positive urine cultures was noted during device use. Bothersome vaginal or urethral irritation occurred in 12% of patients. Adverse events were few and required no therapeutic intervention. CONCLUSIONS: The CapSure shield is a safe and efficacious method of managing stress urinary incontinence in women.

Adult↗
PubMed1997

The risk of Guillain-Barré syndrome after tetanus-toxoid-containing vaccines in adults and children in the United States.

OBJECTIVES: This study examined whether there is a risk that tetanus-toxoid-containing vaccines could cause Guillain-Barré syndrome and, if so, how large the risk is. METHODS: This study was based on previous active surveillance epidemiological studies of Guillain-Barré syndrome and vaccination history. RESULTS: A background rate of 0.3 cases of Guillain-Barré syndrome per million person-weeks has been estimated. By chance, 2.2 people with the syndrome would have received tetanus-toxoid-containing vaccine within the 6 weeks before onset, yet only 1 person had done so. Data on children show similar results. CONCLUSIONS: If an association exists, it must be extremely rare and not of public health significance.

Adult↗
PubMed1997

Hamburger-associated Escherichia coli O157:H7 infection in Las Vegas: a hidden epidemic.

OBJECTIVES: This study sought to determine whether a multistate fast food hamburger-associated outbreak of Escherichia coli O157:H7 infection involved Las Vegas residents as well and, if so, why public health officials had not detected it. METHODS: A matched case-control study was conducted among persons with bloody diarrhea and their healthy meal companions. Hamburger production, distribution, and cooking methods were reviewed. Unused hamburger patties were cultured, and E. coli O157:H7 isolates were characterized. Local laboratory stool culture practices were reviewed. RESULTS: Fifty-eight cases of bloody diarrhea were identified. Illness was associated with eating regular hamburgers (matched odds ratio [OR] = 9.0, 95% confidence interval [CI] = 1.02,433.4), but 25% of ill persons reported eating only jumbo hamburgers. Regular and jumbo hamburger patties yielded E. coli O157:H7 indistinguishable from the lone clinical isolate. No local laboratory cultured routinely for E. coli O157:H7 until after the outbreak. CONCLUSIONS: A large outbreak of E. coli O157:H7 infections escaped timely notice in Las Vegas because local laboratories did not culture for this pathogen. Health officials should encourage laboratories to screen at least all bloody stools on sorbitol-MacConkey medium.

Adolescent↗
PubMed1995

Risk factors for fecal shedding of Escherichia coli O157:H7 in dairy calves.

A case-control study was conducted to determine risk factors for fecal shedding of Escherichia coli O157:H7 (ECO) in dairy calves. Three herds previously found to lack calves that shed ECO in their feces were selected for each herd previously found to have calves that shed ECO. Fecal samples from 965 calves on 64 farms were tested for ECO by microbial culture. Sample prevalence of ECO in calves less than 8 weeks old was 1.4% and in calves 8 weeks or older was 4.8%. Calves were 3 times more likely to shed ECO after weaning than before weaning. Shedding of ECO was associated with grouping calves before weaning; feeding whole cottonseed was negatively associated with ECO shedding. The change in results between testing periods illustrated that an individual herd's status cannot be defined by a single testing of a small sample of cattle.

Age Factors↗
PubMed1995

Antimicrobial-resistant epidemic Shigella dysenteriae type 1 in Zambia: modes of transmission.

To determine the modes of transmission of an epidemic caused by Shigella dysenteriae type I (Sd1) in Zambia, a case-control study was conducted. Case-patients were more likely to have recent contact with a person with dysentery (P = .03) and to have a family member with preceding dysentery (P = .01). Case households were more likely to share their latrine (P = .06). Stored drinking water was obtained by hand-dipping a cup into wide-mouthed vessels or by pouring from narrow-mouthed vessels; case households were more likely to obtain drinking water only by hand-dipping (P = .03). Case-patients were more likely to have eaten relish (a cooked meat or vegetable dish; P = .03) purchased from a vendor. Evidence from this study suggests that Sd1 was transmitted by person-to-person spread, by water stored in vessels that permitted hand-dipping, and by prepared foods sold by vendors. Preventive measures should be directed at these risk factors.

Adolescent↗
PubMed1994

Sequential 1H, 13C, and 15N NMR assignments and solution conformation of apokedarcidin.

Kedarcidin is a recently discovered antitumor antibiotic chromoprotein. The solution conformation of the kedarcidin apoprotein (114 residues) has been characterized by heteronuclear multidimensional NMR spectroscopy. Sequence-specific backbone atom resonance assignments were obtained for a uniformly 13C/15N-enriched sample of apokedarcidin via a semiautomated analysis of 3D HNCACB, 3D CBCA-(CO)NH, 4D HNCAHA, 4D HN(CO)CAHA, 3D HBHA(CO)NH, and 3D HNHA(Gly) spectra. Side-chain assignments were subsequently obtained by analysis of (primarily) 3D HCCH-TOCSY and HCCH-COSY spectra. A qualitative analysis of the secondary structure is presented on the basis of 3J alpha NH coupling constants, deviations of 13C alpha and 13C beta chemical shifts from random coil values, and NOEs observed in 3D 15N- and 13C-edited NOESY-HSQC spectra. This analysis revealed a four-stranded antiparallel beta-sheet, a three-stranded antiparallel beta-sheet, and two two-standed antiparallel beta-sheets. The assignments of cross-peaks in the 3D NOESY spectra were assisted by reference to a preliminary model of apokedarcidin built using the program CONGEN starting from the X-ray structure of the homologous protein aponeocarzinostatin. An ensemble of 15 apokedarcidin solution structures has been generated by variable target function minimization (DIANA program) and refined by simulated annealing (X-PLOR program). The average backbone atom root-mean-square difference between the individual structures and the mean coordinates is 0.68 +/- 0.08 A. The overall fold of apokedarcidin is well-defined; it is composed of an immunoglobulin-like seven-stranded antiparallel beta-barrel and a subdomain containing two antiparallel beta-ribbons. Highly similar tertiary structures have been previously reported for the related proteins neocarzinostatin, macromomycin, and actinoxanthin. Important structural features are revealed, including the dimensions of the chromophore-binding pocket and the locations of side chains that are likely to be involved in chromophore stabilization.

Amino Acid Sequence↗
PubMed1993

An outbreak of cholera in Maryland associated with imported commercial frozen fresh coconut milk.

In August 1991, the first outbreak of cholera associated with an imported commercial food product occurred among persons attending a private picnic. An epidemiologic investigation showed infection with toxigenic Vibrio cholerae O1, biotype El Tor, serotype Ogawa, in 4 of 6 persons who had consumed coconut milk imported from Thailand. In addition, the US Food and Drug Administration recovered toxigenic V. cholerae O1, biotype El Tor, serotype Ogawa, from 1 of 6 unopened bags of the same brand (but different shipment) of coconut milk as that consumed by infected persons. Investigation in Thailand of the manufacturing process of the implicated coconut milk showed several sanitary violations, suggesting that contamination had occurred during production. This outbreak suggests a model of entrance of V. cholerae into a population and shows the need to evaluate current methods of maintaining the safety of imported foods in the United States.

Adult↗
PubMed1993

Adolescent substance abuse: psychosocial factors.

The prevention and management of adolescent substance abuse requires an understanding of the psychosocial context in which such a problem develops. This article reviews literature from the health and behavioral sciences and provides information about the prevalence of substance abuse, family and other psychosocial factors associated with substance abuse, and signs and symptoms of various kinds of substance abuse. Implications for school nursing practice are discussed and suggestions for implementation made.

Adolescent↗
PubMed1992

Overview of contemporary families.

Perceptions and definitions of the term family have always been varied and complex. Hence, an overview of contemporary families is presented here from several perspectives. First, families as they have been perceived by nursing and social science theorists are reviewed. Demographic changes in the family over the last two decades are then presented, followed by an examination of issues faced by families as they change over time. Finally, families as they exist within varying cultural and social contexts are discussed. Emphasis is placed on the need for health care providers to be flexible in defining and working with individual patients and their families.

Critical Care↗
PubMed1985

Lymphoma models for B-cell activation and tolerance. II. Growth inhibition by anti-mu of WEHI-231 and the selection and properties of resistant mutants.

Regulation of the growth of murine B-cell lymphomas has been used as a model for tolerance induction. The inhibition by anti-immunoglobulin reagents of the growth of WEHI-231 and several variant clones has now been studied. The parental line is exquisitely sensitive to growth inhibition by heterologous or monoclonal anti-mu or anti-k reagents and ceases to incorporate thymidine within 24-48 hr of exposure to anti-immunoglobulin reagents. Growth inhibition is initially reversible, but prolonged exposure to anti-mu results in cell death. This inhibition is specific for immunoglobulin light and heavy chains since growth is not inhibited by antibodies directed at either class I or class II histocompatibility antigens. In order to study the mechanism of growth inhibition, we have mutagenized WEHI-231 with ethylmethane sulfonate and cloned the surviving colonies in the presence of anti-mu. Such variants, which have been repeatedly recloned, are able to grow normally in the presence of anti-mu up to 100 micrograms/ml. These "resistant" clones, while expressing amounts of surface IgM similar to that observed on WEHI-231, do not differ markedly in their ability to cap their immunoglobulin receptors compared to the parental line but appear to have lost class II antigens. Cell cycle analysis revealed that anti-mu causes a block in the transition of WEHI-231 from G1 to S phase. The relevance of these processes to models of B-cell tolerance induction are discussed.

Animals↗