Long-term results on VK partial and total temporomandibular joint systems

This article reviews the results obtained on 262 VK partial and total temporomandibular joint (TMJ) procedures followed up to 10 years. VK I total joint (placed 1982 to 1986) cumulative success rate was 44% at 6 years and 20% at 10 years, while VK II (placed 1986 to 1990) cumulative success rate was 80% at 6 years. Material wear of the Teflon FEP surface of the VK I fossa was the most common reason for failure. There were no VK II material failures. A significant improvement in clinical success parameters for both prostheses was found if no previous surgeries were done before VK I or VK II total joint placement. Rib grafts were not helpful after removal of total joint prostheses if patients had a history of multiple procedures. Total TMJ prostheses must be reserved for patients with alternative surgical failures or when these procedures are no longer indicated. Close monitoring by clinical examination and imaging is necessary.     

An expert system to teach troubleshooting of common problems associated with the automated anesthesia recordkeeper

Automated anesthesia recordkeepers have been used to monitor patients during surgery in up to 90% of cases at The Ohio State University. The record-keeping devices are complex and can be difficult to troubleshoot. The 1st-CLASS Fusion Program, an expert system shell-program, has been programmed to allow the resident or nurse anesthetist to solve the two most common types of problems associated with the recordkeeper: printer problems and patient monitor problems. Use of this program allows the resident or nurse anesthetist to troubleshoot the recordkeeper quickly and accurately and promotes in the user a sense of competence and control over the technology.     

Rapid appearance of β-amyloid precursor protein immunoreactivity in glial cells follwing excitotoxic brain injury

Clinical and experimental data have indicated an up-regulation of amyloid precursor protein (APP) after various types of CNS injury. In the present study the cellular source of lesion-induced APP has been investigated an a neurotoxic CNS model. Quinolinic acid injection into the striatum results in neuronal degeneration, while glial cells survive. APP immunoreactivity was detected in glial cells starting at postoperative day 3 and persisted until day 21, the last time point studied. Double immunocytochemistry identified the majority of APP-immunoreactive cells as glial fibrillary acidic protein-immunoreactive astrocytes. There was no evidence of amyloid fibril deposition during this time. It is concluded that following excitotoxic neuronal degneration APP is mainly produced by reactive astrocytes in the lesioned area.     

Body weight and prior depletion affect plasma ascorbate levels attained on identical vitamin C intake: a controlled-diet study

PURPOSE: To evaluate the role of factors that may affect the level of plasma ascorbic acid (AA), including age, body weight, physical activity, minor illness and the impact of prior depletion and repletion. METHODS: After one month of stabilization on 60 mg vitamin C/day, subjects underwent two complete depletion-repletion cycles (one cycle=one month of vitamin C depletion with nine mg/day, followed by one month of repletion with 117 mg per day). Subjects (68 men, ages 30 to 59 years) did not smoke or drink alcohol during the study. All food was provided by the study. RESULTS: There was extreme individual variability in the plasma AA level achieved on an identical repletion dose: after four weeks at 117 mg/day of vitamin C, AA ranged from 26.8 micromol/L to 85.8 micromol/L. Body weight was inversely associated with plasma AA attained (p<0.0001). Regression analysis indicated that, compared to a 130-lb man, a 200-lb man reached 10 micromol/L lower AA after the first repletion and 18 micromol/L lower AA after the second repletion. One-third of the subjects did not reach a plasma plateau after the first repletion. Prior depletion and apparent repletion also had a major impact, and only 10% of subjects reached the same plasma AA on the second repletion as on the first repletion. CONCLUSIONS: Plasma AA attained on a given dose depends on body weight (or dose per kg of body weight) and on whether or not any prior depletions had been repleted adequately. The results have implications for nutrition recommendations and research design.     

Classical conditioning during nitrous oxide treatment: influence of varying the interstimulus interval

Classical conditioning of the rabbit nictitating membrane response (NMR) was accomplished by presenting a 75-ms tone conditioned stimulus (CS) at intervals of 0, 100, 200, 400, and 800 ms before the presentation of a 100-ms shock unconditioned stimulus. Following every four paired trials (tone followed by shock), the occurrence of conditioned responses (CRs) was tested on every fifth trial in which only tone was presented (test trials). Three doses of nitrous oxide in oxygen (0, 33, and 67%) were used during conditioning. Nitrous oxide produced dose-dependent decrements of learning. Conditioned responding was related to the interstimulus interval (ISI) by a concave-down function. The higher dose of nitrous oxide caused more decrements of learning at several ISIs compared to the other two doses, changing the shape of the curve. Trace conditioning, which was examined in the present study, was more impaired under the influence of nitrous oxide than conditioning in a previous study, which used the standard delay paradigm. Thus, the drug impairs explicit memory more than implicit memory.     

Bedside hemodynamic monitoring. Its value in the diagnosis of tamponade complicating cardiac surgery.

Cardiac tamponade may be a difficult clinical diagnosis in the early postoperative period in patients undergoing open-hear surgery, particularly when the anterior or lateral pericardium is left open. Bedside monitoring of intracardiac pressures and determination of a "pressure plateau" between right atrial, right ventricular diastolic, pulmonary arterial diastolic, and pulmonary capillary wedge pressures are useful in the early diagnosis of cardiac tamponade. The value of such hemodynamic monitoring in the diagnosis and treatment of cardiac tamponade in three patients with aorta-coronary artery bypass surgery in the early postoperative period is reported. Appropriate therapy, carried out on the basis of these studies, minimized the occurrence of further morbidity or possible death.     

The HSV 1 genome in quiescently infected NGF differentiated PC12 cells can not be stimulated by HSV superinfection

This study reports that quiescent herpes simplex virus (HSV) type 1 genomes, persisting in long-term infected nerve growth factor (NGF) differentiated PC12 cells, were not stimulated by superinfection with a HSV-1. We have previously shown that HSV-1 can establish long term, quiescent infections in NGF differentiated PC12 cells. To determine if virion associated factors or virus induced gene products could trans-activate the quiescent viral genomes, long term infected PC12 cell cultures were superinfected at a high moi (moi of 20) with a recombinant HSV 17alpha47/lacZ that contains the lacZ gene within the alpha 47 locus. Progeny virus and gene expression from the resident 'quiescent' viral genomes were not detected following superinfection with recombinant 17alpha47/lacZ. The failure to stimulate the quiescent genome appears to be related to the inability of the super infecting virus to induce any gene expression from its own genome following entry into the long term NGF treated PC12 cells. Interestingly, both primary and superinfecting viruses could be stimulated from the quiescently infected cultures following cocultivation with inducer cells. These data suggest that (i) HSV genomes in quiescently infected PC12 cells are unable to be stimulated by incoming virion associated factors and (ii) NGF differentiated PC12 cells maintained in tissue culture for longer than 3 weeks became completely refractory to viral gene expression. The possibilities that these results are reflective of populations of neural cells, in vivo in mouse central nervous system, which are completely refractory to virus gene expression, yet accommodating to the maintenance of viral genomes and thus favor 'latency', are discussed.