The contribution of job satisfaction to the transition from acute to chronic low back pain

The goal of this study was to develop an animal model for the study of acute periodontal disease using silk ligatures in combination with a soft diet in eleven purebred beagle dogs. The silk ligatures were placed subgingivally on the mandible second and fourth premolar on one side of the mouth; the opposite side served as a control. Dogs were monitored during the 16-20 weeks of ligature placement, and for 48 weeks after ligature removal. Development of periodontal disease was evaluated by radiopharmaceutical uptake into bone, radiographic evidence of alveolar bone loss, attachment loss, gingival index and prostaglandin level. Bone loss occurred on the ligatured side during the ligature phase of the study. Radiopharmaceutical uptake was correlated with radiographic evidence of bone loss during the ligature phase. No significant bone loss occurred during the post-ligature phase. Progressive periodontal disease was induced during ligature placement. However, a chronic less aggressive form was not sustained by soft diet alone after ligature removal.     

Changing patterns of mortality across Europe in patients infected with HIV-1. EuroSIDA Study Group

BACKGROUND: The introduction of combination antiretroviral therapy and protease inhibitors has led to reports of falling mortality rates among people infected with HIV-1. We examined the change in these mortality rates of HIV-1-infected patients across Europe during 1994-98, and assessed the extent to which changes can be explained by the use of new therapeutic regimens. METHODS: We analysed data from EuroSIDA, which is a prospective, observational, European, multicentre cohort of 4270 HIV-1-infected patients. We compared death rates in each 6 month period from September, 1994, to March, 1998. FINDINGS: By March, 1998, 1215 patients had died. The mortality rate from March to September, 1995, was 23.3 deaths per 100 person-years of follow-up (95% CI 20.6-26.0), and fell to 4.1 per 100 person-years of follow-up (2.3-5.9) between September, 1997, and March, 1998. From March to September, 1997, the death rate was 65.4 per 100 person-years of follow-up for those on no treatment, 7.5 per 100 person-years of follow-up for patients on dual therapy, and 3.4 per 100 person-years of follow-up for patients on triple-combination therapy. Compared with patients who were followed up from September, 1994, to March, 1995, patients seen between September, 1997, and March, 1998, had a relative hazard of death of 0.16 (0.08-0.32), which rose to 0.90 (0.50-1.64) after adjustment for treatment. INTERPRETATION: Death rates across Europe among patients infected with HIV-1 have been falling since September, 1995, and at the beginning of 1998 were less than a fifth of their previous level. A large proportion of the reduction in mortality could be explained by new treatments or combinations of treatments.     

Dietitians employed by health care facilities preferred a HACCP system over irradiation or chemical rinses for reducing risk of foodborne disease

OBJECTIVE: To survey dietitians in health care facilities about the acceptability of alternative meat and poultry processing methods designed to reduce the risk of foodborne disease and their willingness to pay for these processes. SUBJECTS: A geographically representative sample of 600 members of The American Dietetic Association who work in health care facilities. The response rate was 250 completed questionnaires from 592 eligible subjects (42%). DESIGN: A mail survey was used to gather information on the acceptability of a Hazard Analysis and Critical Control Point (HACCP) system, chemical rinses, and irradiation for increasing the safety of food. Discrete choice contingent valuation was used to determine the acceptability at current prices and at 5, 10, and 25 cents per pound above current prices. STATISTICAL ANALYSES: Logistic regression was used to estimate mean willingness to pay (the maximum amount respondents are willing to pay) for each process. A simultaneous equations regression model was used to estimate the effects of other variables on acceptability. RESULTS: Respondents expressed a high level of concern for food safety in health care facilities. The estimated mean willingness to pay was highest for a HACCP system and lowest for chemical rinses. CONCLUSIONS/APPLICATIONS: The successful adoption of alternative methods to increase food safety depends on their acceptance by foodservice professionals. The professionals sampled were most accepting of a HACCP system, somewhat less accepting of irradiation, and least accepting of new chemical rinses. Poultry and beef processors and government agencies concerned with food safety may want to take into account the attitudes of foodservice professionals.     

Low-molecular-weight heparins

Low-molecular-weight heparins (LMWH) are a new group of parenteral anticoagulants. They represent a major clinical advance in anticoagulation since the identification of unfractionated heparin (UFH) in 1922 and the introduction of the synthetic coumarin derivative, warfarin, in 1948. Their predictable pharmacokinetics, increased bioavailability, and longer plasma half-life allow for once- or twice-daily dosing and eliminate the need for routine laboratory monitoring. This simplified administration stands to alter the clinical practice of anticoagulation. This review high-lights recent clinical trials and focuses on studies comparing LMWH with the other two major anticoagulants: UFH and coumadin.     

Neural discharge and local field potential oscillations in primate motor cortex during voluntary movements

We develop a statistical thermodynamic model for the phase evolution of DNA-cationic lipid complexes in aqueous solution, as a function of the ratios of charged to neutral lipid and charged lipid to DNA. The complexes consist of parallel strands of DNA intercalated in the water layers of lamellar stacks of mixed lipid bilayers, as determined by recent synchrotron x-ray measurements. Elastic deformations of the DNA and the lipid bilayers are neglected, but DNA-induced spatial inhomogeneities in the bilayer charge densities are included. The relevant nonlinear Poisson-Boltzmann equation is solved numerically, including self-consistent treatment of the boundary conditions at the polarized membrane surfaces. For a wide range of lipid compositions, the phase evolution is characterized by three regions of lipid to DNA charge ratio, rho: 1) for low rho, the complexes coexist with excess DNA, and the DNA-DNA spacing in the complex, d, is constant; 2) for intermediate rho, including the isoelectric point rho = 1, all of the lipid and DNA in solution is incorporated into the complex, whose inter-DNA distance d increases linearly with rho; and 3) for high rho, the complexes coexist with excess liposomes (whose lipid composition is different from that in the complex), and their spacing d is nearly, but not completely, independent of rho. These results can be understood in terms of a simple charging model that reflects the competition between counterion entropy and inter-DNA (rho < 1) and interbilayer (rho > 1) repulsions. Finally, our approach and conclusions are compared with theoretical work by others, and with relevant experiments.     

Structure-activity requirements for flavone cytotoxicity and binding to tubulin

A series of 79 flavones related to centaureidin (3,6,4'-trimethoxy-5, 7,3'-trihydroxyflavone, 1) was screened for cytotoxicity in the NCI in vitro 60-cell line human tumor screen. The resulting cytotoxicity profiles of these flavones were compared for degree of similarity to the profile of 1. Selected compounds were further evaluated with in vitro assays of tubulin polymerization and [3H]colchicine binding to tubulin. Maximum potencies for tubulin interaction and production of differential cytotoxicity profiles characteristic of 1 were observed only with compounds containing hydroxyl substituents at C-3' and C-5 and methoxyl groups at C-3 and C-4'.     

Perioperative morbidity and mortality of high-dose-rate gynecologic brachytherapy

PURPOSE: To determine the 30-day morbidity and mortality rates for patients with an intact uterus undergoing high-dose-rate (HDR) brachytherapy, and to assess risk factors which may predict for these potentially life-threatening complications. METHODS AND MATERIALS: From August 1989 to December 1994, 128 cervical and 41 medically inoperable endometrial cancer patients were treated with 5 outpatient weekly HDR brachytherapy insertions. Patients with cervical cancer also were treated with external beam radiotherapy. Acute events that resulted in either hospitalization (morbidity) or death (mortality) within 30 days of the implant were analyzed. Univariate and multivariate analyses were performed to identify risk factors. RESULTS: Overall there were 16 acute events in 169 patients (9.5%). The overall morbidity and mortality rates for the cervical and endometrial patients were 5.5%, 1.6%, 7.3%, and 9.8%, respectively. The following factors were significant by univariate analysis: age per decade, American Society of Anesthesiologists (ASA) score, Karnofsky Performance Status (KPS), significant medical history, diagnosis of cervical vs. endometrial cancer, and mean time exceeding 160 minutes for the procedure. Since age was the most significant predictive factor (p = 0.0003), bivariate analyses were performed by adjusting for age. In these analyses only ASA and KPS maintained significance, while a positive medical history was of borderline significance (p = 0.07). CONCLUSION: The morbidity and mortality rates observed in gynecologic patients selected for HDR brachytherapy were similar to low-dose-rate, but higher than other HDR reports. Reasons for this include a higher risk population, especially those with medically inoperable endometrial cancer. In the cervical cancer patients, some of the complications may have also been a result of the external beam portion of the radiation. In order to minimize the acute complications observed in the present HDR brachytherapy system, the following changes have been implemented: appropriate patient selection, anesthesiology involvement to monitor conscious sedation for high-risk patients, external beam radiotherapy alone in patients at extremely high risk, deep vein thrombosis (DVT) prophylaxis, use of intraoperative ultrasound, shorter duration in the brachytherapy suite, and preradiation treatment plans (plans executed prior to the insertion) if applicable. Finally, this analysis suggests that these procedures should be performed in a hospital-based setting where appropriate support is available.     

Fasciotomy, chronic venous insufficiency, and the calf muscle pump

OBJECTIVE: To test the hypothesis that fasciotomy may impair the function of the calf muscle pump, which in turn could result in the development of chronic venous insufficiency. DESIGN: A cohort study of patients with a history of lower extremity fasciotomy. SETTING: An urban trauma center. PATIENTS: Seventeen of the 83 patients identified through trauma, vascular, and/or orthopedic registries consented to participation in this study. INTERVENTIONS: Participating patients completed a study questionnaire, and then underwent a complete vascular examination, including air plethysmographic (APG) assessment. Patients with a history of venous injuries were also studied with color flow duplex venous imaging. MAIN OUTCOME MEASURES: Function of the calf muscle pump as measured by APG, and evidence of chronic venous insufficiency as measured by APG, findings on clinical examination, and by venous ultrasonography. RESULTS: Seventeen patients completed the study, including 8 with a history of vascular injuries, 6 with old fractures, and 3 who had undergone fasciotomy for soft tissue infections. The time from injury to examination ranged from 5 months to 20 years. Eight patients had signs or symptoms of venous insufficiency, the severity of which appeared to be time dependent. The APG data showed significant mean differences between fasciotomy and control extremities in ejection fraction (P<.001) and residual volume fraction (P<.001), both measures of calf muscle pump function. There were no significant changes in venous filling index, a measure of venous reflux, or in outflow fraction, which correlates with venous obstruction. There were no differences in APG variables between patients with vascular injuries vs those with orthopedic or soft tissue injuries. CONCLUSIONS: Lower extremity fasciotomy impairs long-term calf muscle pump function, as measured by APG, in patients with and without vascular injuries. These patients are at risk for the long-term development of chronic venous insufficiency following lower extremity trauma.