Evaluation of four elastomeric interocclusal recording materials

Background: The fabrication of dental prosthesis requires the transfer of interocclusal records from patient's mouth to semiadjustable articulators using different kinds of recording media. Any inaccuracy in these interocclusal records leads to occlusal errors in the final prosthesis. This study was conducted to evaluate the dimensional changes occurring in the interocclusal recording material over a given period of time and the material's resistance to compression during the cast mounting on the articulator.     

Reduction of bacterial adherence to catheter surface with heparin

Despite many advances in catheter design and use, the most common cause of hospital-acquired infections is catheterization of the urinary tract. In the present investigation the adherence of bacteria to catheters coated with heparin was studied. Since heparin itself does not coat the plastic catheter surface, a complex of heparin with tridodecylmethylammonium chloride (TDMAC) was used which results in hydrophobic association of hydrocarbon chains of the TDMAC with the catheter leaving the quaternary ammonium moiety of TDMAC exposed to the surface forming ionic bonds with the highly anionic sulfate groups of heparin. Coating latex catheter material with TDMAC without heparin resulted in 3.6-fold higher adherence whereas coating with the TDMAC-heparin complex reduced adherence to less than 10% of control untreated latex. TDMAC-heparin also significantly reduced bacterial adherence to teflon coated latex (Bardex) and vinyl catheter material. Less than 30% of the original heparin was removed after wash periods of up to one week. These results indicate that TDMAC-heparin coating of urethral catheters reduces bacterial adherence and thereby may delay the acquisition of catheter associated urinary tract infection.     

Erection and ejaculation in man. Assessment of the electromyographic activity of the bulbocavernosus and ischiocavernosus muscles

Electromyographic (EMG) recordings were obtained by concentric needle electrodes from the bulbocavernosus (BC) and ischiocavernosus (IC) muscles in 7 human volunteers during excitement to erection and subsequent ejaculation. Simultaneous registration of the time course and volume of each expressed spurt of semen was obtained using an aluminium pan suspended in front of the subject's penis on a force transducer the output of which was charted with the EMG activity. The BC and IC muscles showed no EMG activity during erection and detumescence cycles induced by visual sex stimulation. In 5 of 7 subjects, the first EMG burst of the BC in ejaculations induced by masturbation was not correlated with an expelled spurt of semen as were subsequent bursts. However, only 26 to 60% of the total number of EMG bursts were accompanied by expulsion of a spurt of semen. There thus appears to be a large safety factor in the striated muscle expulsive mechanism. Oral phenoxybenzamine treatment in 2 subjects did not significantly affect either the number of EMG bursts of the BC or the subjective pleasure of the orgasm but did significantly reduce the volume of semen expelled. Semen volume does not appear to be a unique determinant of the pleasure felt or the trigger for ejaculation.     

Temporal Changes in Micturition and Bladder Contractility after Sucrose Diuresis and Streptozotocin-induced Diabetes Mellitus in Rats

Studies were done to compare the acute effects of streptozotocin-induced diabetes and sucrose consumption on micturition, bladder mass and contractile responses of bladder strips to field stimulation and contractile agonists. Micturition changes occurred gradually in diabetic rats, reached maximal values within 7 to 14 days, and were accompanied by significant increases in bladder mass after 7 days. Bladder strips from diabetics responded to field stimulation, carbachol and KCl with significantly greater contractions than did those from controls within 7 days. Sucrose-drinking rats had maximal increases in fluid consumption and micturition frequency on the first night after starting treatment. Increases in micturition volumes were slower to develop than in diabetics. Bladder mass was significantly increased 30 and 60 days after starting sucrose treatment. Bladder strips from sucrose-drinking rats responded to field stimulation and carbachol with significantly greater contractions than did those from controls only after 60 days. Monitoring of drinking and micturition patterns established that diabetic rats drink and urinate during both the dark and light cycles. In contrast, control and sucrose-drinking rats drink and urinate principally at night. The results demonstrate that differences in bladder function between diabetic and sucrose drinking rats are apparent during the first month after treatment begins. The data suggest that the effects of diabetes and sucrose consumption on contractile bladder function are related to the diuresis-induced increases in bladder mass.     

Noncardiac surgery in long-term implantable left ventricular assist-device recipients.

OBJECTIVE: The authors describe their experience with left ventricular assist-device (LVAD) recipients undergoing noncardiac surgery and delineate surgical, anesthetic, and logistic factors important in the successful intraoperative management of these patients. SUMMARY BACKGROUND DATA: Left ventricular assist-devices have become part of the armamentarium in the treatment of end-stage heart failure. As the numbers of patients chronically supported with long-term implantable devices grows, general surgical problems that are commonly seen in other hospitalized patients are becoming manifest. Of particular interest is the intraoperative management of patients undergoing elective noncardiac surgical procedures. METHODS: The anesthesia records and clinical charts were reviewed for eight ventricular assist-device recipients undergoing general surgical procedures between August 1, 1990 and August 31, 1994. RESULTS: A total of 12 procedures were performed in 6 men and 2 women averaging 52.7 years of age. Mean time elapsed from device implantation to operation was 68 +/- 35 days. Conventional inhalational and intravenous anesthetic techniques were well tolerated in these patients undergoing diverse surgical procedures. No perioperative mortality was observed. Five of eight patients went on to successful cardiac transplantation. CONCLUSIONS: Hemodynamic recovery after LVAD insertion has defined a new group of patients who develop noncardiac surgical problems often seen in other critically ill patients. Recognition of the unique potential problems that the LVAD recipient may encounter in the perioperative period--in particular patient positioning, device limitations, and fluid and inotropic management--will ensure an optimal surgical outcome for LVAD recipients undergoing noncardiac surgery.     

Hyperperfusion of ictal seizure focus demonstrated by MR perfusion imaging.

MR using a susceptibility-weighted sequence and dynamic contrast enhancement with gadolinium demonstrated relative hyperperfusion of the right temporoparietal cortex in a patient in focal status epilepticus. A single-photon emission CT (SPECT) scan also demonstrated hyperperfusion of the right temporoparietal cortex. Perfusion MR, SPECT, and electroencephalogram normalized when the seizures ended.     

What does gerontology mean?

Despite growth in the field of gerontological research over the past 50 years, no consensus has emerged on either the definition of gerontology or on its scope and boundaries. This confusion is rooted historically in developments involving the origins and adoption of the term. These include the divergent agendas and world views of particular disciplines and gerontological institutions, as well as conflicts over both ideology and turf among major gerontologists. Speculation is offered on the potential, as well as the costs, of developing consensus-in the future.