Inability to activate muscles maximally during cocontraction and the effect on joint stiffness

In order to determine the maximum joint stiffness that could be produced by cocontraction of wrist flexor and extensor muscles, experiments were conducted in which healthy human subjects stabilized a wrist manipulandum that was made mechanically unstable by using positive position feedback to create a load with the characteristics of a negative spring. To determine a subject's limit of stability, the negative stiffness of the manipulandum was increased by increments until the subject could no longer reliably stabilize the manipulandum in a 1° target window. Static wrist stiffness was measured by applying a 3° rampand-hold displacement of the manipulandum, which stretched the wrist flexor muscles. As the load stiffness was made more and more negative, subjects responded by increasing the level of cocontraction of flexor and extensor muscles to increase the stiffness of the wrist. The stiffness measured at a subject's limit of stability was taken as the maximum stiffness that the subject could achieve by cocontraction of wrist flexor and extensor muscles. In almost all cases, this value was as large or larger than that measured when the subject was asked to cocontract maximally to stiffen the wrist in the absence of any load. Static wrist stiffness was also measured when subjects reciprocally activated flexor or extensor muscles to hold the manipulandum in the target window against a load generated by a stretched spring. We found a strong linear correlation between wrist stiffness and flexor torque over the range of torques used in this study (20–80% maximal voluntary contraction). The maximum stiffness achieved by cocontraction of wrist flexor and extensor muscles was less than 50% of the maximum value predicted from the joint stiffness measured during matched reciprocal activation of flexor and extensor muscles. EMG recorded from either wrist flexor or extensor muscles during maximal cocontraction confirmed that this reduced stiffness was due to lower levels of activation during cocontraction of flexor and extensor muscles than during reciprocal contraction.     

Maudsley reactive (MR/Har) and nonreactive (MNRA/Har) rats: performance in an operant conflict paradigm.

The present studies were designed to characterize the behavior of Maudsley reactive (MR/Har) and nonreactive (MNRA/Har) rats in a modification of the Geller-Seifter operant conflict paradigm. Food-restricted (85% of free-feeding weights) female MR/Har and MNRA/Har rats were trained to lever press for food reinforcement in a multiple-schedule operant conflict paradigm. In the absence of a tone, a fixed ratio-30 (FR-30) schedule for reinforcement only was in effect (i.e., every 30th lever press resulted in the delivery of a 45-mg food pellet). During the presence of a tone, a fixed ratio-1 (FR-1) schedule of both reinforcement (food) and punishment (0.20 mA footshock applied for 500 ms) was in effect (i.e., each lever press resulted in both food and shock delivery). The tone periods were 27 s in duration and were presented on a variable interval (VI)-120-s schedule (approximately 20 tones/40-min session). Behavioral testing was conducted 5 days/week for 35 weeks. Initially, punished responding between the MR/Har and MNRA/Har rat strains did not differ dramatically. However, over the course of many weeks of conflict testing, rats of the MNRA/Har strain came to accept significantly more shocks than did subjects of the MR/Har strain. A direct examination of footshock sensitivity in these rats revealed that this difference in conflict behavior over time was not due to strain differences in shock sensitivity. The mechanism for this time-dependent difference in conflict behavior between the MR/Har and MNRA/Har rats remains undetermined.     

Clotrimazole induction of cytochrome P-450: dose-differentiated isozyme induction

Treatment of male rats for 3 days with the N-substituted imidazole, clotrimazole, produced up to a 4-fold induction of hepatic microsomal cytochrome P-450. The monooxygenase activities induced varied with the dose administered. At low doses (less than 25 mg/kg), p-nitroanisole demethylase and aniline hydroxylase activities were induced. Only at higher doses were other monooxygenase activities (erythromycin and ethylmorphine demethylases and cytochrome P-450 metabolic-intermediate complex formation from troleandomycin) induced. Microsomal UDP-glucuronosyltransferase activity toward morphine was induced at low doses in a manner similar to that of p-nitroanisole demethylase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of microsomes indicated that low doses of clotrimazole caused the intensification of a 48,000 molecular weight protein band, whereas at high doses, there was a marked intensification of an additional 50,500 molecular weight protein, the same molecular weight band as was intensified in phenobarbital- and dexamethasone-induced microsomes. The observations suggest a phenomenon of "dose-differentiated" isozyme induction for cytochrome P-450.     

High Case-Fatality Rate for Human Anthrax,Northern Ghana, 2005–2016

The human cutaneous anthrax case-fatality rate is ≈1% when treated, 5%–20% when untreated. We report high case-fatality rates (median 35.0%; 95% CI 21.1%–66.7%) during 2005–2016 linked to livestock handling in northern Ghana, where veterinary resources are limited. Livestock vaccination and access to human treatment should be evaluated.     

Translating clinical and patient-reported data to tailored shared decision reports with predictive analytics for knee and hip arthritis

Quality of Life Research - New informatics tools can transform evidence-based information to individualized predictive reports to serve shared decisions in clinic. We developed a web-based system...     

Combining clinical judgement and statistical data in expert systems: Over-the-telephone management decisions for critical congenital heart disease in the first month of life

When a new-born baby with congenital heart disease is referred to a regional specialist centre, the transportation management is crucial but must be decided on the basis of clinical information obtained over the telephone. We consider algorithmic and naive statistical approaches to helping in this decision, and on the basis of preliminary results the relative strengths and weaknesses are discussed. A synthesised logical and probabilistic approach appears to have the best potential and could be implemented on hand-held computers.Paper presented at symposium on Computer-assisted Decision Support and Database Management in Anaesthesia, Intensive Care and Cardio-pulmonary Medicine, Rotterdam, 1988.     

Sexual harassment at work: issues and answers for health care administrators

Sexual harassment is not new to the health care industry. What is new is that recent media attention has heightened awareness that sexual harassment is illegal. This fact, coupled with the substantial liability that employers may incur if they fail to control sexual harassment, mandates the need for outlining the major issues relative to sexual harassment in today's health care setting. This article gives particular emphasis to the fact that sexual harassment can be prevented by taking a proactive stance.     

Use of Sequentially Administered Stable Lead Isotopes to Investigate Changes in Blood Lead during Pregnancy in a Nonhuman Primate (Macaca fascicularis)

The effects of pregnancy on the flux of lead from maternal bonewere investigated in five females from a unique colony of cynomolgusmonkeys (Macaca fascicularis) which had been dosed orally withlead (approximately 1100–1300 µg Pb/kg body wt)throughout their lives (about 14 years). Through the use ofstable lead isotopes ²⁰⁴Pb, ²⁰⁶Pb, and ²⁰⁷Pb, it was possibleto differentiate between the lead contributed to blood leadfrom the skeleton and the lead contributed from the currentoral dose. Blood samples and bone biopsy samples taken before,during, and after pregnancy were analyzed for lead (total andstable isotope ratios) by thermal ionization mass spectrometry.Through the use of end-member unmixing equations, the contributionto blood of lead from maternal bone during pregnancy was estimatedand compared to the contribution of lead from maternal bonebefore pregnancy. A 29 to 56% decrease in bone lead mobilizationin the first trimester was followed by an increase in the secondand third trimesters, up to 44% over baseline levels. In onemonkey, the third-trimester increase did not reach baselinelevels. In a single low-lead monkey, a similar decrease in thefirst trimester was followed by a 60% increase in the thirdtrimester, indicating that a similar pattern of flux is seenover a wide range of lead concentrations. Analysis of maternalbone and fetal bone, brain, liver, and kidneys confirmed a substantialtransplacental transfer of endogenous lead. Lead concentrationsin fetal bone often exceeded maternal bone lead concentrations.From 7 to 39% of the lead in the fetal skeleton originated fromthe maternal skeleton.