Comparison of stress transmission in the IMZ implant system with polyoxymethylene or titanium intramobile element: a finite element stress analysis.

Using the finite element method, this study modeled a 4.0 x 13.0-mm IMZ implant, restored with a cast gold crown, to examine the influence of the polyoxymethylene (POM) intramobile element (IME) on the transmission of vertical and oblique forces. Stress concentrations in the bone and in components of the implant system were much greater under a 30-degree load than under an equal vertical load. Stress transmission to bone occurred chiefly in the crestal region, and these stresses were not reduced when the IME was modeled in POM rather than in titanium. Maximum stress concentrations occurred in the fastening screw.     

Cholesterol, coronary heart disease, and total mortality in middle-aged and elderly men and women in Tecumseh.

Relationships between serum cholesterol and coronary heart disease (CHD) were investigated in Tecumseh men and women who were 45 to 92 years old and initially free of CHD. Recruitment continued through three cycles of examinations over a period of 10 years, beginning in 1959. Follow-up for mortality ended in 1986 to 1987. Age-adjusted relative risks for CHD death for cholesterol levels of 5.2 to 6.2 mmol/L and greater than 6.2 mmol/L, compared with levels less than 5.2 mmol/L for men aged 45 to 64 years, were 1.2 and 1.7; for older men they were 1.0 and 1.8. Comparable relative risks for CHD death by cholesterol level were .7 and 1.4 for 45- to 64-year-old women and .8 and .7 for older women. Coefficients for cholesterol were significant for fatal CHD in men under and those 65 years and older when age, systolic blood pressure, body mass index, cigarette smoking status, and glucose intolerance were controlled in proportional hazards models. Cholesterol was a significant predictor of fatal CHD plus nonfatal myocardial infarction in middle-aged, but not elderly women. Relative risks for total mortality were lowest for middle-aged men and women with cholesterol levels of 5.2 to 6.2 mmol/L and the difference was significant in men.     

Thoracoscopic pleurodesis in persistent and recurrent pneumothorax]

103 patients with recurrent or persistent pneumothorax have been treated with local application of fibrin and talcum by a thoracoscopic procedure. The method was successful in 97 patients (94.2%) and lead to a stable and complete reexpansion of the lung within 6.3 days. As a direct consequence of the procedure itself only a few and minor complications occurred during a mean hospitalization-time of 10.4 days. The longterm followup over a mean period of 6.4 years revealed a recurrence rate of 15%, although half of the episodes occurred early during the first three months. After 6 years, 80% of the patients were completely asymptomatic and spirometric lung function was restored to normal values. We therefore consider thoracoscopic pleurodesis to be a successful and safe method for treating complicated pneumothorax.     

The fast release of mucin secretion from human colonic cells induced by Entamoeba histolytica is dependent on contact and protein kinase C activation.

The mucus producing colonic cell line, LS174T, was used as a model to study E. histolytica-induced mucin secretion. E. histolytica trophozoites in contact with the mucus layer overlying the LS174T cells and in response to PMA, a protein kinase C activator, and Ca2+ ionophore A23187 which elevates intracellular Ca2+ ([Ca]i), caused a time-dependent (0.25-2.00 h) release of mucin. PKC inhibitors, H7 and staurosporine inhibited E. histolytica (37 and 75%) and PMA (46 and 100%)-induced mucin secretion, whereas in response to Ca2+ ionophore mucin secretion was augmented (56 and 17%). Both PMA and E. histolytica-induced the translocation of the PKC enzyme from the cytoplasm to the membrane fraction with increased enzyme activity. These results suggest that even though mucin secretion can be induced by PKC and Ca(2+)-dependent pathways, E. histolytica evokes the fast release of mucins by a PKC-dependent mechanism.     

Distraction effects on muscle: Leg lengthening studied in rabbits

We investigaed changes in the anterior tibial muscle during lengthening of the lower leg in rabbits. In 37 rabbits, an osteotomy of the right middle tibia was performed and was fixed by a unilateral external fixator. The rabbits were randomized into 6 groups. In groups 1, 2, and 3 the tibiae were distracted 0.5 mm/day. In groups 1 and 2, the rabbits were killed after 14 and 28 days of distraction, respectively, and in group 3 after 28 days of distraction, followed by 14 days of rest. Groups 1a, 2a, and 3a served as controls. They were treated similarly as groups 1, 2, and 3, but no distracton was performed. Proliferating cell nuclei were labeled with 5-bromo-2-deoxyuridine and were identified by immunohistochemical staining. The weight of the muscle was measured. During bone lengthening the muscle showed signs of growth, as indicated by increasing weight and number of proliferating cell nuclei. This was observed only during lengthening and it ceased when the lengthening was stopped.