Complications of gallstone disease in kidney transplantation patients.

BACKGROUND: We studied the complications of gallstone disease in kidney transplantation patients and evaluated whether the screening and treatment of gallstones before acceptance to the kidney waiting list is relevant. METHODS: Complications of gallstone disease were evaluated in 1608 kidney transplantation patients on cyclosporine and long-term steroid treatment with median age 45.5 years, transplanted between 1990 and 2000. To evaluate the prevalence of cholecystolithiasis after kidney transplantation an abdominal ultrasound examination was cross-sectionally performed to a subgroup of 304 patients and the results were correlated to their serum lipid values, changes in BMI and use of statins. RESULTS: Pre-transplant cholecystectomy due to cholecystolithiasis (prerequisite for acceptance to kidney waiting list) had been performed on 71 (4%) of the patients. Thirty (15%) patients with diagnosed post-transplant gallstones and four without gallstones developed biliary complications. There were 25 cases of cholecystitis of which three resulted in gallbladder perforations. Seventeen patients (50%) with biliary complications required urgent surgery and one (3%) patient died of post-operative complications. In the subgroup of ultrasound examination patients (median 7 years post-transplant follow-up) 81% of the patients had no gallstones and 9% of the patients had gallstones had developed after transplantation. Patients with pre-transplant gallstones were older (P < 0.01) and patients with post-transplant gallstones gained the most weight during the follow-up. No differences in lipid values were found. CONCLUSION: In transplantation patients, the complications of gallstone disease may be severe. Screening and treatment of pre- and post-transplantation gallstone disease are recommended.

[Caldesmon inhibits formation of strongly bound myosin cross-bridges and activates an ability of weakly bound cross-bridges to transform actin monomers to the off-conformation]. / Kal'desmon podavliaet formirovanie sil'nosviazannykh poperechnykh miozinovykh mostikov i aktiviruet sposobnost' slabosviazannykh mostikov transformirovat' sub"edinitsy aktina v vykliuchennuiu konformatsiiu.

The effect of caldesmon and its actin-binding C-terminal 35 kDa fragment on conformational alterations of actin in a muscle fiber at relaxation, rigor and at simulation of strong and weak binding of myosin heads to actin was studied by polarizational fluorimetry technique. The strong and weak binding forms were mimicked during binding of F-actin of ghost muscle fibers to myosin subfragment-1 modified with NEM (NEM-S1) or pPDM (pPDM-S1), respectively. As a test for alterations in actin conformation, changes in orientation and mobility of a fluorescent probe, TRITC-phalloidin, bound specifically to F-actin were used. The results obtained have shown that during transition of the muscle fiber from the relaxed state into the rigor and during binding of actin filaments to NEM-S1, changes of polarization parameters take place, which are characteristic of formation between actin and myosin of the strong binding and of transformation of actin subunits from the "turned-off" (inactive) to the "turned-on" (active) conformation. Binding of pPDM-S1 to actin and relaxation of the muscle fiber are accompanied, on the contrary, by the changes of orientation and of the fluorescent probe mobility, which are typical of formation of the weak ("non-force-producing") form of actin-myosin binding and of transformation of actin subunits from the active conformation into the inactive one. Caldesmon and its C-terminal fragment markedly inhibit formation of the strong binding at rigor and activate transition of actin monomers to the switched off conformation at relaxation of muscle fiber. In parallel experiments, these regulatory proteins have been shown to inhibit an active force developed at the transition of a muscle fiber from relaxation to rigor. Besides, caldesmon and its fragment decrease the rate of actin filament sliding over myosin in an in vitro motility assay. Caldesmon is suggested to regulate the smooth muscle contraction in an allosterical manner. The alterations in actin conformation inhibit formation of strong binding of myosin cross bridges to actin and activate the ability of weakly bound cross bridges to switch actin monomers from the "on" to the "off" conformation.