Biomedical subjects
Publications and source records attributed to L Gottlieb.
[reaction: see text] TATP gives rise to two separable conformations because the barrier for interconversion between them is relatively high at room temperature. This kind of behavior is rare in cyclic organic systems and is the result of poor overlap in the "flip-flop" transition state. The crystal structure of the analogous tricyclohexanone triperoxide also indicates the presence of two conformers.
Sexually mature virgin adult males of the green stink bug, Acrosternum hilare attracted sexually mature virgin adult females in laboratory bioassays using a vertical Y-tube. There was no indication that males attracted other males, or that females attracted either sex. These results suggested that A. hilare males produce a sex pheromone. Extracts of odors collected from sexually mature males contained compounds that were not present in extracts from females or sexually immature males. (4S)-Cis-(Z)-bisabolene epoxide ((4S)-cis-Z-BAE) was the major sex-specific component of the extract. The crude extract was attractive to female A. hilare, but when separated into four fractions, only the portion containing (4S)-cis-Z-BAE and the minor component (4S)-trans-Z-BAE was attractive to females. This fraction was as attractive as the crude extract, suggesting that the former contained all the pheromone components. Neither synthetic (4S)-cis-Z-BAE nor (4S)-trans-Z-BAE alone was attractive to females, but a 95:5 cis:trans blend, mimicing the ratio naturally produced by males, was attractive to females in Y-tube bioassays. Bioassays in a field cage showed that significantly more A. hilare females were attracted to cotton string lures treated with 1 mg of a 95:5 blend of (4S)-cis-Z-BAE and (4S)-trans-Z-BAE placed inside a bouquet of alfalfa than to an alfalfa bouquet containing a pentane-treated control. In field cage studies, attraction of females was greatest during the late afternoon and evening hours, and female A. hilare approached the synthetic pheromone source almost exclusively by walking.
OBJECTIVE: To determine the effect of intravenous glutamine supplementation vs. an isonitrogenous control on infectious morbidity in severely burned patients. Previous clinical studies in seriously ill patients suggest a beneficial effect of glutamine on infectious morbidity, but no trials have examined possible clinical benefits in severely burned patients. DESIGN: Prospective, double-blind, randomized trial. SETTING: Burn intensive care unit of a university hospital. PATIENTS: Twenty-six severe burn patients with total burn surface area of 25% to 90% and presence of full-thickness burns. Patients were evaluated for occurrence of bacteremia and antibiotic use during the first 30 days of their burn unit admission. Nutritional status and overall inflammation were also measured. INTERVENTION: Either intravenous glutamine or an isonitrogenous control amino acid solution was administered as a continuous infusion during burn intensive care unit stay. MEASUREMENTS AND MAIN RESULTS: The incidence of Gram-negative bacteremia was significantly reduced in the glutamine-supplemented group (8%) vs. control (43%; p <.04). No difference was seen in the incidence of Gram-positive bacteremia or fungemia. Average number of positive blood cultures, antibiotic usage, and mortality rates also were reduced but did not reach statistical significance. Significant improvements in serum transferrin and prealbumin were observed in glutamine-supplemented patients at 14 days after burn injury (p <.01 and.04, respectively). C-reactive protein was also significantly reduced at 14 days after burn injury in the glutamine group (p <.01). CONCLUSIONS: Significantly fewer bacteremic episodes with Gram-negative organisms occurred in the glutamine-supplemented patients. Glutamine supplementation improved measures of nutrition and decreased measures of overall inflammation. In addition, a trend toward lower mortality rate, decreased overall bacteremia incidence, and antibiotic usage in the glutamine group was observed. Glutamine's beneficial effects may be a result of improved gut integrity or immune function, but the precise mechanism of glutamine's protection is unknown.
Despite evidence over the past decade that patients like and will use patient-centered computing systems in managing their health, patients have remained forgotten stakeholders in advances in clinical computing systems. We present a framework for patient empowerment and the technical realization of that framework in an architecture called CareLink. In an evaluation of the initial deployment of CareLink in the support of neonatal intensive care, we have demonstrated a reduction in the length of stay for very-low birthweight infants, and an improvement in family satisfaction with care delivery. With the ubiquitous adoption of the Internet into the general culture, patient-centered computing provides the opportunity to mend broken health care relationships and reconnect patients to the care delivery process. CareLink itself provides functionality to support both clinical care and research, and provides a living laboratory for the further study of patient-centered computing.
Spent Saccharomyces cerevisiae cells from a beer fermentation process were evaluated for lead cation sorption. The crude biomass was washed with water and acetone prior to any other treatment. Although the washed biomass showed substantial lead ion sorption it was susceptible to microbial spoilage. Different aldehydes were tested as chemical fixation agents; however, most of them caused drastic lowering of the metal uptake capacity. However, benzaldehyde was not only an excellent fixation agent, but the biomass treated with it also retained its original lead sorption capacity. A mechanism for the fixation process is suggested.
Frostbite injuries have traditionally been treated with expectant observation. With the exception of early blister aspiration tissues are allowed to demarcate before definitive debridement is accomplished. Triple-phase bone scanning has been used to define the extent of fatally damaged tissues in an attempt to allow for early debridement and wound closure. We suggest extending this technology to assess injury and direct debridement in patients for whom early aggressive salvage attempts are indicated. We present two cases in which triple-phase scanning was used to direct early debridement for aggressive limb salvage with flap reconstruction. Bone, ligament, tendon, and nerve were preserved and covered with vascularized tissue before the onset of frank necrosis. Postoperative scans reveal revascularization of these tissues. An algorithm incorporating triple-phase scanning for the evaluation and treatment of frostbite is presented.
BACKGROUND: Data about the frequency of adverse events related to inappropriate care in hospitals come from studies of medical records as if they represented a true record of adverse events. In a prospective, observational design we analysed discussion of adverse events during the care of all patients admitted to three units of a large, urban teaching hospital affiliated to a university medical school. Discussion took place during routine clinical meetings. We undertook the study to enhance understanding of the incidence and scope of adverse events as a basis for preventing them. METHODS: Ethnographers trained in qualitative observational research attended day-shift, weekday, regularly scheduled attending rounds, residents' work rounds, nursing shift changes, case conferences, and other scheduled meetings in three study units as well as various departmental and section meetings. They recorded all adverse events during patient care discussed at these meetings and developed a classification scheme to code the data. Data were collected about health-care providers' own assessments about the appropriateness of the care that patients received to assess the nature and impact of adverse events and how health-care providers and patients responded to the adverse events. FINDINGS: Of the 1047 patients in the study, 185 (17.7%) were said to have had at least one serious adverse event; having an initial event was linked to the seriousness of the patient's underlying illness. Patients with long stays in hospital had more adverse events than those with short stays. The likelihood of experiencing an adverse event increased about 6% for each day of hospital stay, 37.8% of adverse events were caused by an individual, 15.6% had interactive causes, and 9.8% were due to administrative decisions. Although 17.7% of patients experienced serious events that led to longer hospital stays and increased costs to the patients, only 1.2% (13) of the 1047 patients made claims for compensation. INTERPRETATION: This study shows that there is a wide range of potential causes of adverse events that should be considered, and that careful attention must be paid to errors with interactive or administrative causes. Healthcare providers' own discussions of adverse events can be a good source of data for proactive error prevention.
The two-dimensional position of markers in radiographs for Roentgen Stereophotogrammetric Analysis (RSA) is usually determined using a measuring table. The purpose of this study was to evaluate the reproducibility and the accuracy of a new RSA system using digitized radiographs and image-processing algorithms to determine the marker position in the radiographs. Four double-RSA examinations of a phantom and 18 RSA examinations from six patients included in different RSA-studies of knee prostheses were used to test the reproducibility and the accuracy of the system. The radiographs were scanned at 600 dpi resolution and 256 gray levels. The center of each of the tantalum-markers in the radiographs was calculated by the computer program from the contour of the marker with the use of an edge-detection software algorithm after the marker was identified on a PC monitor. The study showed that computer-based image analysis can be used in RSA-examinations. The advantages of using image-processing software in RSA are that the marker positions are determined in an objective manner, and that there is no need for a systematic manual identification of all the markers on the radiograph before the actual measurement.
A woman experienced multiple episodes of pocket erosion after placement of an implantable cardioverter defibrillator culminating in a pocket infection. The device was placed in a retroperitoneal location, and the patient has not developed further episodes of pocket erosion or infection. Interrogation of the device in this position and its subsequent replacement have been straightforward.
Exposure of rats to hyperoxia is associated with increased active Na+ transport in rat lungs and increased Na,K-adenosine triphosphate (ATPase) expression in alveolar epithelial cells. Hyperbaric oxygenation (HBO) has been reported to act as an accelerated model of hyperoxic cell damage. Sublethal and intermittent exposure to HBO, however, has been suggested to upregulate endogenous protective mechanisms. In the present study, we tested whether short-term HBO, prior to inducing lung injury, would upregulate lung Na,K-ATPase. The results show that HBO, either intermittent or single 2.5 h exposure, increased lung Na,K-ATPase alpha-1 and beta-1 messenger ribonucleic acid (mRNA) transcript levels up to fourfold. Na,K-ATPase activity in lungs of rats exposed to HBO increased twofold during the first 2 h following removal from the hyperbaric chamber, and remained elevated for up to 6 h following HBO. Conceivably, the increase in Na,K-ATPase activity following HBO is due to an increase in activity from a basal to a higher rate, or possibly due to recruitment/translocation of Na,K-ATPases from inner membranes to the plasma membrane.
The material properties of ten 2-O suture materials were evaluated tensiometrically at time = 0 and again after 6 weeks incubation in rats. All suture material was incubated and tested without knots. Specialized machinery was used with a custom securing apparatus to pull suture material apart at constant speed. Stress-strain curves were derived, and from these strength, toughness, strain at rupture, and elastic modulus were determined. Sutures tested included Vicryl [poly(glycolide-lactide)], Dexon (polyglycolic acid), Ethibond (polyester), silk, plain gut, chromic gut, Maxon (polyglyconate), PDS (polydioxanone), nylon, and Prolene (polypropylene). Elastic modulus was greatest for braided, least for monofilament, and intermediate for gut sutures, regardless of chemical composition (ANOVA, P = 0.0001). Strength, strain, and toughness decreased in all of the sutures over time in vivo with the exception of braided polyester (Ethibond), which remained stable. Silk demonstrated the least strength and toughness while PDS and Maxon were the strongest and toughest at time = 0. Vicryl, Dexon, and gut sutures were absorbed to the point that they could not be tested after 6 weeks in vivo. Performance tables are provided for all sutures.
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OBJECTIVE: This study was conducted to determine whether a specialized form of nursing could help prevent or reduce psychosocial maladjustment among children, aged 4 to 16 years, with chronic physical disorders. In contrast to other studies, nurses were chosen to provide the intervention based on their central role in health care and the appropriateness of their training for this task. METHODOLOGY: A clinical trial was conducted in which 332 children and their families were randomly assigned either to receive this specialized nursing for a 1-year period, or to remain in the control condition. The children were all active outpatients in nine clinics at the Montreal Children's Hospital. Three measures of psychosocial functioning administered before and after the intervention were the basis for assessing its efficacy. The measures included the behavior problems profile of the Achenbach Child Behavior Checklist, the Personal Adjustment and Role Skills, completed by the parents, and two versions of the Self-Perception Profile (Harter) for children aged 4 to 7 years and 8 to 16 years. RESULTS: Differences between groups were examined both categorically and quantitatively. In the former, the percent of children with clinical scores (those above or below a cut-off indicative of maladjustment) at baseline and postintervention were compared. In the latter, the mean scores at the end of the trial were analyzed using analysis of covariance with the baseline scores as covariates. Statistically significant positive differences were found in the domain of anxiety/depression on the Personal Adjustment and Role Skills, and in the areas of scholastic competence, behavior, and global self-worth on the Harter. CONCLUSION: The results indicate that this intervention helps children with chronic disorders by preventing or reducing maladjustment. Most university-prepared nurses already have the basic skills required to achieve these results; only a modest investment in reorientation may be needed. Thus, other pediatric centers should be able to replicate these findings and thereby take a major step toward improving the lives of children with chronic disorders.
BACKGROUND: The identification and removal of adenomatous polyps and post-polypectomy surveillance are considered to be important for the control of colorectal cancer. In current practice, the intervals between colonoscopies after polypectomy are variable, often a year long, and not based on data from randomized clinical trials. We sought to determine whether follow-up colonoscopy at three years would detect important colonic lesions as well as follow-up colonoscopy at both one and three years. METHODS: Patients were eligible if they had one or more adenomas, no previous polypectomy, and a complete colonoscopy and all their polyps had been removed. They were randomly assigned to have follow-up colonoscopy at one and three years or at three years only. The two study end points were the detection of any adenoma, and the detection of adenomas with advanced pathological features (defined as those > 1 cm in diameter and those with high-grade dysplasia or invasive cancer). RESULTS: Of 2632 eligible patients, 1418 were randomly assigned to the two follow-up groups, 699 to the two-examination group and 719 to the one-examination group. The percentage of patients with adenomas in the group examined at one and three years was 41.7 percent, as compared with 32.0 percent in the group examined at three years (P = 0.006). The percentage of patients with adenomas with advanced pathological features was the same in both groups (3.3 percent). CONCLUSIONS: Colonoscopy performed three years after colonoscopic removal of adenomatous polyps detects important colonic lesions as effectively as follow-up colonoscopy after both one and three years. An interval of at least three years is recommended before follow-up colonoscopy after both one and three years. An interval of at least three years is recommended before follow-up examination after colonoscopic removal of newly diagnosed adenomatous polyps. Adoption of this recommendation nationally should reduce the cost of post-polypectomy surveillance and screening.
The effect of a distal site of nerve compression on neural regeneration after a nerve repair was investigated in the rat model. After chronic compression had been established by placement of a Silastic band about a distal site of the posterior tibial nerve, the proximal posterior tibial nerve was divided, and then immediately repaired. Beginning 6 months after nerve repair, neural regeneration, assayed by walking track analysis, demonstrated significantly impaired function in the group of rats with a distal site of compression, compared with the repair group without a distal site of compression (p < .05). Followed for 3 additional months, neural function further significantly (p < .001) deteriorated in the group with distal compression. Morphometric analysis demonstrated that both the nerve repair alone and repair-plus-compression groups had 1) significantly decreased axon and nerve-fiber diameters (p < .001), and 2) significantly increased myelinated nerve-fiber density (p < .001), compared with normal; these findings are consistent with neural regeneration. However, the repair-plus-compression group had significantly (p < .03) fewer regenerating fibers than did the repair-without-distal-compression group. This experimental study suggests that consideration be given to release of sites of known anatomic narrowing in close proximity to a nerve reconstruction.
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