"Patch-glue" annular reconstruction for mitral valve replacement in severely calcified mitral annulus

Mitral valve replacement in severe annular calcification may be complicated by atrioventricular rupture, left circumflex coronary artery injury, and thromboembolic events. Mitral valve replacement was performed in 2 patients with massive annular calcification, by suturing a Tissucol fibrin glue-treated Teflon patch on the posterolateral atrial wall. After 30 and 34 months, respectively, the valve was normally functioning and the patients were asymptomatic and free from hemorrhagic and thromboembolic events.     

Oxidation and colour development in AES resins

Summary The structural changes connected with the beginning of colour development during thermal oxidation of a AES polymer blend have been investigated. The yellowing behaviour of AES has been compared with that of the different components of the blend, and the influence of oxygen partial pressure on the polymer degradation has been determined. Colour changes have been shown to be correlated with the early stages of oxidation, and at the same time the different stabilities of the blend components were verified.     

Hepatic Retransplantation--an analysis of risk factors associated with outcome

Hepatic retransplantation is controversial because the results are inferior to primary transplants and organs are so scarce. To determine the factors that are associated with poor outcome within the first year following retransplantation, we performed a multivariate analysis, using stepwise logistic regression, of 418 hepatic retransplantations performed at a single institution from November 1987 to December 1993. The minimum follow-up was 1 year. Seven variables were found to be independently associated with subsequent graft failure (defined as either patient death or retransplantation): donor age (odds ratio 2.2 for each 10-year increase over age 45, 95% CI 1.3 to 3.7), female donor sex (odds ratio 1.7, 95% CI 1.05 to 2.7), recipient age (odds ratio 1.6 for each 10-year increase over age 45,95% CI 1.2 to 2.8), need for preoperative mechanical ventilation (odds ratio 1.8, 95% CI 1.1 to 2.9), pretransplant serum creatinine (odds ratio 1.24 for each increase of 1 mg/dl, 95% CI 1.1 to 1.4), pretransplant total serum bilirubin (odds ratio 1.4 for each 10-mg/dl increase over 15 mg/dl, 95% CI 1.1 to 1.8), and the primary immunosuppressant, using tacrolimus as the reference category (odds ratio for cyclosporine-based immunosuppression 3.9, 95% CI 2.3 to 6.8). Although not part of the logistic regression model, the timing of retransplantation was also found to be important, with the overall probability of failure increasing from 0.58 on day 0 to a peak of 0.8 on day 38 and decreasing slowly after that. The implications of these results regarding the appropriateness of retransplantation are discussed.     

Prospective research on fetal cholelithiasis: incidence, predisposing conditions, echographic diagnosis, and clinical features

The Authors report a prospective study on fetal cholelithiasis, analyzing its differences with the more widely known cholelithiasis of paediatric age. The study shows that the number of cases diagnosed by ultrasonography is higher than expected (0.39%, 3 cases on 764 pregnancies). The Authors could find no correlation between fetal cholelithiasis and any maternal, obstetrical and fetal factor. They have focused attention on sonographic imaging showing clinical-instrumental correlation between echogenic material, clinical features and their evolution. The study confirms that the most common evolution results in spontaneous resolution of fetal endocholecystic pathological images. Finally, wide review of the international literature is reported on the rare, but possible clinical manifestations and their complications.     

Potassium channels in epithelial cells

The broad array of K- channels in epithelial cells includes voltage-dependent (mainly outward) and Ca(2+)-activated channels, and K+ channels modulated by adenosine triphosphate (ATP). Voltage-dependent K+ channels mediate Na+/K+ absorption and secretion; typically, they are found in the basolateral membrane and exhibit burst activity. Ca(2+)-activated K+ (Ca2+/K+) channels regulate activity by decreasing Ca2+ influx via voltage-gated Ca2+ channels. Ca2+/K+ channels exhibit conductances of 4-300 pS, and have a low open probability (< 10(-7)) at the level of the resting membrane potential. ATP-sensitive channels have been observed mainly in insulin-secreting pancreatic beta-cells and in the urinary tract, where the open state is rapidly closed by ATP. The channels are voltage-dependent, exhibit burst activity, and, in the case of the urinary-tract cells, are Ca2+ dependent. Chemical compounds that selectively open or block K+ channels have been exploited to characterize channels found in different cells, but no opener or blocker has been found that specifically affects only one type of K+ channel. Specialized model systems and recombinant techniques have led to a general understanding of the structure of K+ channels, but many important details remain to be determined.     

Electrical Correlates of Acupuncture Points

Employing a Wheatstone bridge, skin conductance was measured over those putative acupuncture points on the large intestine and pericardium meridians lying between the metacarpophalangeal joints and the elbow. Results were compared to those from anatomically similar locations devoid of acupuncture points. At most acupuncture points on most subjects, there were greater electrical conductance maxima than at control sites.     

Kinetics of abnormal grain growth in pure iron

Grain growth after primary recrystallization in unstrained and strained specimens of pure iron is examined during isothermal anneals at three different temperatures (664, 680, 690° C). Undeformed specimens undergo continuous grain growth, while the deformed ones show a stage of rapid discontinuous growth. The peculiar characteristics of the abnormal growth kinetics, and in particular the presence of three well-defined stages of growth, are brought out by plotting, versus annealing time, the ratio between the mean grain diameters of deformed and undeformed samples. The parametersn (exponent of the kinetic equation) andQ (apparent activation energy) are determined.