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T Wright

Publications and source records attributed to T Wright.

At least 55 records · Page 3Linked to original sources
PubMed1998

Behavioral and demographic risk factors for transmission of human immunodeficiency virus type 1 in heterosexual couples: report from the Heterosexual HIV Transmission Study.

We compared 224 heterosexual couples who were discordant for human immunodeficiency virus (HIV) type 1 infection (one partner HIV infected) with 78 HIV-concordant couples (both partners HIV infected) to identify demographic and behavioral risk factors for HIV transmission. Among the 229 couples whose male partner was first infected, HIV-concordant couples had engaged in anal sex more frequently before and after knowing that the male was infected than had HIV-discordant couples. Pap smears of grade 2 or higher (inflammation) were more prevalent among the second-infected female partners in HIV-concordant couples than among uninfected women in discordant couples (58% vs. 23%; P < .001). Anal sex and unprotected vaginal sex after knowledge of a male partner's infection were significant correlates of concordance in a multivariate logistic model, as were ethnicity, marital status, and antiviral therapy. Ethnicity strongly predicted concordance, even after controlling for sexual risk behaviors and stage of disease.

Adult↗
PubMed1998

Extreme hypoventilation reduces ventilator-induced lung injury during ventilation with low positive end-expiratory pressure in saline-lavaged rabbits.

OBJECTIVE: To compare the degrees of ventilator-induced lung injury caused by two ventilation protocols. DESIGN: Randomized trial. SETTING: University animal laboratory. SUBJECTS: Sixteen New Zealand white rabbits. INTERVENTIONS: After five sequential saline lung lavages, eight pairs of anesthetized rabbits were allocated randomly to receive either of two ventilation protocols for 4 hrs during neuromuscular blockade. Both groups received 3 cm H2O of positive end-expiratory pressure and 100% oxygen. Control group animals received an estimated tidal volume of 12 mL/kg, an inspiratory time of 0.7 sec, and a ventilatory rate adjusted for a PaCO2 of 35 to 45 torr (4.7 to 6 kPa). Study group animals were ventilated through an intratracheal catheter, with inspiratory time of 1.5 secs, ventilatory rate of 20 breaths/min, and peak inspiratory pressure of 4 to 8 cm H2O, adjusted to maintain PaCO2 at 150 to 250 torr (20 to 33 kPa). MEASUREMENTS AND MAIN RESULTS: Arterial blood gases were measured every 30 mins. After 4 hrs, a final lung lavage was performed. Physiologic parameters, cell counts and protein concentration in the final lavage, and lung histology were compared between groups. The alveolar-arterial oxygen tension gradient was higher in the study group over the first 1.5 hrs, but the time profile showed significantly (p = .001) greater improvement in the study group. After 4 hrs, the mean alveolar-arterial oxygen tension gradient was lower in the study group (94 torr [12.5 kPa] vs. 201 torr [26.8 kPa]). The increase in neutrophil count from the initial to the final lung lavage was lower in the study group (0.27 x 10(7) cells/L vs. 2.01 x 10(7) cells/L, p = .037), as was the absolute value of the neutrophil count in the final lavage (1.33 x 10(7) cells/L vs. 3.02 x 10(7) cells/L, p = .04). The median hyaline membrane score was lower in the study group (0.5 vs. 3.0) but the difference was not statistically significant. CONCLUSION: These findings suggest that a very low tidal volume reduces ventilator-induced lung injury in saline-lavaged rabbits during ventilation at low lung volume.

Animals↗
PubMed1998

Nondisruptive, in vivo method for biomechanical characterization of linear incision wound healing: preliminary report.

Previous work on in vivo biomechanical characterization of soft tissues and wound healing has led to the development of a methodology for nondisruptive, in vivo biomechanical analysis of linear incision wounds. The purpose of this preliminary study was to define nondisruptive biomechanical parameters that characterize progressive healing and compare them with an in vivo disruptive parameter of ultimate pressure at failure (in vivo strength). Male Sprague-Dawley rats (n = 60), each weighing 250 to 300 gm, were anesthetized and underwent creation of paired full-thickness linear incision wounds. The rats were divided into three groups (n = 10/group per time period): control group, nothing applied to either wound; carrier group, bovine serum albumin applied to each wound; transforming growth factor-beta2 group, transforming growth factor-beta2 in bovine serum albumin applied to each wound. On postoperative days 5 and 10, rats from each group underwent in vivo biomechanical testing using the Dimensional Analysis System (Dimensional Analysis Systems, Inc., Nashville, Tenn.). This computer-driven device integrates a video camera and processor with a vacuum controller, valve, and transducer to provide measurements of tissue deformation (in millimeters) and negative pressure (mmHg) as a multiaxial stress (vacuum) is applied to a wound. On each rat, one incision was tested disruptively and the other incision was tested nondisruptively. Disruptive data were measured as ultimate pressure (mmHg) at failure, or the amount of pressure required to disrupt the wound. Nondisruptive data were measured for tissue stiffness (kiloPascals) during application of negative pressure (maximum, 80 mmHg). On postoperative day 5, wounds treated with transforming growth factor-beta2 had significantly increased in vivo wound strength compared with carrier wounds. The nondisruptive parameter of tissue stiffness was also significantly increased for the transforming growth factor-beta2 treated wounds, thus supporting the disruptive data. On postoperative day 10, there was no difference in mean wound strength or mean tissue stiffness among any of the groups. These preliminary data represent the first report of in vivo, nondisruptive biomechanical characterization of linear incision wounds. The results suggest that through in vivo measurements of tissue stiffness, differences can be detected between treatment groups. Because the healing wound may be characterized without the need for disruption, this methodology should allow for consecutive, in vivo biomechanical testing of wounds in future wound healing studies.

Animals↗
PubMed1998

Relationship between exhaled nitric oxide and childhood asthma.

The purpose of the study was to determine if exhaled nitric oxide levels in children varied according to their asthmatic and atopic status. Exhaled nitric oxide was measured in a sample of 93 children attending the North West Lung Centre, Manchester, United Kingdom, for the clinical evaluation of a respiratory questionnaire being developed as a screening tool in general practice. The clinical assessment included full lung function, skin prick testing, and exercise challenge. Children were said to be asthmatic either by consensus decision of three independent consultant pediatricians, who reviewed all the clinical results except the nitric oxide measurements, or by positive exercise test. Atopic asthmatic children had higher geometric mean exhaled nitric oxide levels (consensus decision, 12.5 ppb [parts per billion] 95% CI, 8.3 to 18. 8; positive exercise test, 12.2 ppb 95% CI, 7.6 to 19.7) than did nonatopic asthmatic children (3.2 ppb 95% CI, 2.3 to 4.6; 3.2 ppb 95% CI, 2.0 to 5.0), atopic nonasthmatic children (3.8 ppb 95% CI, 2. 7 to 5.5; 5.7 ppb 95% CI, 4.1 to 8.0), or nonatopic nonasthmatic children (3.4 ppb 95% CI, 2.8 to 4.1; 3.5 ppb 95% CI, 3.0 to 4.1). Thus, exhaled nitric oxide was raised in atopic asthmatics but not in nonatopic asthmatics, and these nonatopic asthmatics had levels of exhaled nitric oxide similar to those of the nonasthmatics whether atopic or not.

Adolescent↗
PubMed1998

Continuous passive motion after repair of the rotator cuff. A prospective outcome study.

Despite the apparent success of continuous passive motion after soft-tissue procedures or joint replacements, its effect after repair of the rotator cuff is still unknown. The purpose of this prospective, randomized outcome study was to compare the results of continuous passive motion with those of manual passive range-of-motion exercises after repair of the rotator cuff. Thirty-one patients (thirty-two rotator cuffs) were randomly assigned to one of two types of postoperative management: continuous passive motion (seventeen patients) or manual passive range-of-motion exercises (fifteen patients). There were seventeen women and fourteen men, and the mean age was sixty-three years (range, thirty to eighty years). The patients were followed for a mean of twenty-two months (range, six to forty-five months). Five tears of the rotator cuff were small, eighteen were medium, and nine were large. All of the operations were performed by one surgeon. The patients who were managed with continuous passive motion used the device for the first four weeks postoperatively. The patients who were managed with manual passive range-of-motion exercises were assisted by a trained relative, friend, or home-care nurse. After the four-week period, the two groups were managed similarly for two to five months. According to the Shoulder Pain and Disability Index, a valid and reliable self-administered questionnaire, the treatment was extremely successful in both groups. The overall score was excellent for twenty-seven shoulders (84 per cent), good for two (6 per cent), fair for two (7 per cent), and poor for one (3 per cent). With the numbers available, we could detect no significant differences (p > 0.05) between the two groups with respect to the score according to the Index, pain (according to a visual-analog scale), range of motion, or isometric strength. Manual passive range-of-motion exercises were more cost-effective than continuous passive motion. The limited number of physical-therapy visits associated with the manual passive range-of-motion exercises in the present study appeared to be more cost-effective than a traditional physical-therapy schedule of three visits per week. Postoperative therapy with continuous passive motion or manual passive range-of-motion exercises appears to yield favorable results after repair of a small, medium, or large tear of the rotator cuff.

Adult↗
PubMed1998

A field test comparison of hiking stick use on heartrate and rating of perceived exertion.

The purpose of this study was to compare heartrate carrying a load and rating of perceived exertion with and without hiking sticks while ascending and descending a slope. 11 novice, moderately fit volunteers, ages 18 to 21 years (M = 19.3 yr.) completed two alternate 50-meter, uphill and downhill hikes on a 40 degrees slope during randomly ordered trials with and without fitted hiking sticks and backpacks (15 kg). Paired t test comparisons for 4 trials indicated that mean heartrate was significantly lower only following the first ascent by those using hiking sticks than those without sticks. Rating of perceived exertion also was significantly lower (p < .05) for those using hiking sticks. Perhaps heartrate may be lower at the onset of climbing using hiking sticks, but as the duration the hike is extended, heartrates become comparable, presumably due to the transfer of energy utilization from the legs to the upper body.

Adolescent↗
PubMed1998

Long-term complications of snake bites to the upper extremity.

The purpose of this study was to determine long-term complications of upper-extremity snake envenomations. The records of 73 patients, who were seen for snake bites were obtained; 46 of these patients had bites to the upper extremity, and 27 had bites to the lower extremity. These patients were graded according to the severity of the bite. The snakes involved were eastern diamondback rattlesnake, coral snake, pigmy rattlesnake, water moccasin, and unknown. Fourteen of the 46 patients receiving upper extremity bites were examined by a hand surgeon and an occupational hand therapist 1 to 3.2 years after their bite. Subjective pain data, range-of-motion, intrinsic, extrinsic, finger-flexion tightness, grip strength, pinch strength and objective sensory data were collected. Four patients had continued pain and tissue atrophy at the bite site. There were no long-term sequelae from a missed compartment syndrome.

Adult↗
PubMed1997

Retransplantation of patients with severe posttransplant hepatitis B in the first allograft.

BACKGROUND: The outcome of orthotopic liver transplantation (OLTX) in patients retransplanted for severe hepatitis B virus (HBV) in the first allograft has been poor due to high rates of HBV reinfection and even more aggressive disease in the second graft. Recent data suggest that hepatitis B immunoglobulin (HBIg) given after transplantation can be successful in delaying or preventing HBV reinfection in patients transplanted for chronic hepatitis B cirrhosis. We report the successful retransplantation of patients who developed recurrent or de novo hepatitis B after OLTXY. METHODS: Using similar HBIg regimens, two centers retransplanted seven patients after they developed recurrent or de novo hepatitis B in the first allograft. At retransplantation all seven patients were HBs antigen (Ag) positive; four patients were positive for HBeAg and HBV DNA by immunoblot assay, two patients were negative for HBeAg and HBV DNA, and one patient was positive for HBV DNA and negative for HBeAg. All patients were either HDV Ag or anti-HDV negative. One patient was anti-HCV positive. All patients received HBIg infusions after retransplantation to maintain serum anti-HBs levels >500 IU/L indefinitely. RESULTS: After retransplantation, six of seven patients are alive (86%): all are without evidence of HBV recurrence with serum negative for HBsAg, HBeAg, and HBV DNA by immunoblot assay. Liver biopsies are normal on routine studies with immunohistochemical stains for HBcAg and HBsAg also being negative. Mean follow-up of these six patients is 40.1 months (range 21-63 months). One patient (14%) developed HBV reinfection 7 months after his second transplant, in spite of maintaining target anti-HBs levels. He maintained stable liver function with minimal evidence of clinical hepatitis B, but died 8 months later from an unrelated stroke. CONCLUSIONS: We conclude that patients with recurrent or de novo hepatitis B after OLTX can be successfully retransplanted using aggressive immunoprophylaxis to prevent HBV reinfection. The failure of HBIg therapy in one patient underscores the need for other effective adjunctive anti-HBV modalities.

Adult↗
PubMed1997

Diversity and depth-specific distribution of SAR11 cluster rRNA genes from marine planktonic bacteria.

Small-subunit (SSU) ribosomal DNA (rDNA) gene clusters are phylogenetically related sets of SSU rRNA genes, commonly encountered in genes amplified from natural populations. Genetic variability in gene clusters could result from artifacts (polymerase error or PCR chimera formation), microevolution (variation among rrn copies within strains), or macroevolution (genetic divergence correlated with long-term evolutionary divergence). To better understand gene clusters this study assessed genetic diversity and distribution of a single environmental SSU rDNA gene cluster, the SAR11 cluster. SAR11 cluster genes, from an uncultured group of the alpha subclass of the class Proteobacteria, have been recovered from coastal and midoceanic waters of the North Atlantic and Pacific. We cloned and bidirectionally sequenced 23 new SAR11 cluster 16S rRNA genes, from 80 and 250 m in the Sargasso Sea and from surface coastal waters of the Atlantic and Pacific, and analyzed them with previously published sequences. Two SAR11 genes were obviously PCR chimeras, but the biological (nonchimeric) origins of most subgroups within the cluster were confirmed by independent recovery from separate gene libraries. Using group-specific oligonucleotide probes, we analyzed depth profiles of nucleic acids, targeting both amplified rDNAs and bulk RNAs. Two subgroups within the SAR11 cluster showed different highly depth-specific distributions. We conclude that some of the genetic diversity within the SAR11 gene cluster represents macroevolutionary divergence correlated with niche specialization. Furthermore, we demonstrate the utility for marine microbial ecology of oligonucleotide probes based on gene sequences amplified from natural populations and show that a detailed knowledge of sequence variability may be needed to effectively design these probes.

Animals↗
PubMed1996

It's good to talk.

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Ethics, Nursing↗
PubMed1996

Expression of c-Fos in subcutaneous adipose tissue of the fetal pig.

Subcutaneous adipose tissue from fetal pigs was examined for c-Fos expression in developing adipocytes. Enhanced c-Fos expression was found in the nuclei of adipocytes and cells closely associated with fat cell clusters from 75 and 105 day old fetuses. 50 day old fetuses which had no adipocytes showed no enhanced c-Fos expression in undifferentiated cells. c-Fos expression in adipocytes was not transient, but persisted through the gestational period from 75 to 105 days. The timing of c-Fos induction appears to be closely related to adipocyte differentiation and was found only in developing adipocytes and cells closely associated with fat cell cluster and was not found in independent stromal-vascular cells.

Adipocytes↗
PubMed1996

Development of a multivariate statistical algorithm to analyze human cervical tissue fluorescence spectra acquired in vivo.

BACKGROUND AND OBJECTIVE: A general multivariate statistical algorithm has been developed to analyze the diagnostic content of cervical tissue fluorescence spectra acquired in vivo. MATERIALS AND METHODS: The primary steps of the algorithm are to: (1) preprocess the data to reduce inter-patient and intra-patient variation of tissue spectra within a diagnostic category, without a priori information, (2) dimensionally reduce the preprocessed fluorescence emission spectrum with minimal information loss and use it to select the minimum number of the original emission variables of the fluorescence spectrum required to achieve classification with negligible decrease in predictive ability, and (3) assign a posterior probability to the diagnosis of each sample, so that samples with relative uncertain diagnosis can be reevaluated by a clinician. The algorithm was tested retrospectively and prospectively on cervical tissue spectra acquired from 476 sites from 92 patients at 337 nm excitation. RESULTS: The algorithm based on the entire fluorescence spectrum differentiates squamous intraepithelial lesions (SILs) from normal squamous epithelia and inflammation with an average sensitivity and specificity of 88% +/- 1.4 and 70% +/- 1, respectively. The average sensitivity and specificity of the identical algorithm based on intensity selected at only two emission wavelengths is 88% +/- 1.4 and 71% +/- 1.4, respectively. CONCLUSION: The multivariate statistical algorithm based on both types of spectral inputs at 337 nm excitation has a similar sensitivity and significantly improved specificity relative to colposcopy in expert hands.

Algorithms↗
PubMed1996

Spectroscopic diagnosis of cervical intraepithelial neoplasia (CIN) in vivo using laser-induced fluorescence spectra at multiple excitation wavelengths.

BACKGROUND AND OBJECTIVE: The diagnostic contribution of cervical tissue fluorescence spectra acquired in vivo at 380 and 460 nm excitation were analyzed using a general multivariate statistical algorithm. MATERIALS AND METHODS: The primary steps of the algorithm are to: (1) preprocess data to reduce interpatient and intrapatient variation of tissue spectra from the same diagnostic category, without a priori information, (2) dimensionally reduce the pre-processed spectral data using Principal Component Analysis, and (3) develop a probability based classification scheme based on logistic discrimination using the diagnostically useful principal components. The algorithm was tested on cervical tissue spectra acquired from 165 sites at 380 nm excitation and from 147 sites at 460 nm excitation. A retrospective and prospective estimate of the algorithm's performance was determined. RESULTS: At 460 nm excitation, (1) SILs can be differentiated from normal squamous tissues with an average sensitivity and specificity of 91% +/- 1.3 and 75.5% +/- 1, respectively; furthermore, (2) high grade SILs can be differentiated from low grade SILs with an average sensitivity and specificity of 80% +/- 4 and 76% +/- 5, respectively. In addition, using tissue spectra at 380 nm excitation, SILs can be differentiated from normal columnar epithelia and inflammation with an average sensitivity and specificity of 77% +/- 1 and 72% +/- 9, respectively. CONCLUSIONS: Fluorescence spectra at multiple excitation wavelengths are essential for the detection and differential diagnosis of SILs at colposcopy.

Algorithms↗