Revealing biophysical properties of KfrA-type proteins as a novel class of cytoskeletal, coiled-coil plasmid-encoded proteins.

BACKGROUND: DNA binding KfrA-type proteins of broad-host-range bacterial plasmids belonging to IncP-1 and IncU incompatibility groups are characterized by globular N-terminal head domains and long alpha-helical coiled-coil tails. They have been shown to act as transcriptional auto-regulators. RESULTS: This study was focused on two members of the growing family of KfrA-type proteins encoded by the broad-host-range plasmids, R751 of IncP-1ß and RA3 of IncU groups. Comparative in vitro and in silico studies on KfrAR751 and KfrARA3 confirmed their similar biophysical properties despite low conservation of the amino acid sequences. They form a wide range of oligomeric forms in vitro and, in the presence of their cognate DNA binding sites, they polymerize into the higher order filaments visualized as "threads" by negative staining electron microscopy. The studies revealed also temperature-dependent changes in the coiled-coil segment of KfrA proteins that is involved in the stabilization of dimers required for DNA interactions. CONCLUSION: KfrAR751 and KfrARA3 are structural homologues. We postulate that KfrA type proteins have moonlighting activity. They not only act as transcriptional auto-regulators but form cytoskeletal structures, which might facilitate plasmid DNA delivery and positioning in the cells before cell division, involving thermal energy.

[Advantages and controversies regarding physiologic electrostimulation of the heart in sinus node disease]. / Korzysci i kontrowersje tzw. fizjologicznej elektrostymulacji serca w chorobie wezla zatokowego.

UNLABELLED: Pacing mode in sinus node disease (SND) is one of controversies in cardiac pacing. We evaluated atrial pacing mode (AAI) in SND patients (pts). Between 1985 and 1994 AAI pacemaker was inserted in 179 pts due to symptomatic SND of varied etiology. RESULTS: The majority of pts (91.6%) were free from syncopal episodes after AAI implantation, in 15 pts (8.4%) syncopes were occasionally observed due to disturbances in pacemaker function, AVB III degrees, vaso-vagal syndrome, orthostatic hypotonia or atherosclerotic insufficiency of the cerebral circulation. In 49 (51%) out of 96 pts with brady-tachy syndrome (BTS), episodes of supraventricular tachyarrhythmia were not observed after AAI insertion and in the majority of the remaining pts the frequency of the episodes decreased significantly. Chronic atrial fibrillation developed in 5 (5.2%) pts. In some of the pts the symptoms related to chronic heart failure decreased or disappeared. A reoperation was performed in 44 (24%) pts due to electrode dislocation or fracture, atrio-ventricular conduction disturbances, an increase in pacing threshold or due to local infections. During the follow-up period 13 (7.3%) pts died of reasons unrelated to cardiac pacing therapy. CONCLUSION: In the majority of SND pts AAI pacing mode prevents from syncopal episodes caused by sinus node disfunction. It decreases the symptoms of heart failure in SND pts and stabilizes the sinus rhythm in the majority of BTS pts. Complications accompanying AAI do not post a major threat for the pts and can be easily resolved. They should by no means discourage from AAI implantation in SND.

Rhabdomyomas of female genital tract. Report on two cases.

Studies were conducted by means of optical light and electron microscopy into two cases of rhabdomyoma of a fetal type in the vagina of a patient, 42 years of age, and in the ectocervical region of a patient aged 39 years. Both cases were similar to one another for optical and ultrastructural features and revealed high maturity of the rhabdomyomatous cells in tumors. A review of the literature would reveal the cases presented to be the 20th case of a vaginal tumor and the 3rd case of ectocervical tumor so far described as rhabdomyomas of the female genital tract.

[Concentration of kininogens and low molecular kininogen antigen in plasma of pregnant rabbits and newborn progeny in health and following intravenous infusion of purified thrombin]. / Stezenie kininogenów i antygenu kininogenu drobnoczasteczkowego w osoczu ciezarnych królic i noworodków króliczych w stanie zdrowia i po dozylnym wlewie trombiny.

High levels of trypsin-releasing kinin and low molecular plasma kininogen antigen were detected in plasma of pregnant female rabbits. Respective values in plasma of their new born progeny was 2.7 times lower than that in maternal plasma. Intravenous infusion of the highly purified bovine thrombin administered to pregnant female rabbits markedly decreased plasma fibrinogen platelet count and increased fibrinogen/fibrin degradation products in blood serum. A marked decrease of trypsin-releasing kinin plasma levels accompanied these changes. No changes in the kininogen antigen levels were seen during the same experiments. Thrombin infusions administered to pregnant female rabbits did not produce measurable changes in trypsin-releasing kinin levels and plasma low molecular kininogen antigen in the progeny obtained for the investigations with the aid of cesarean section.

Experimental arteriosclerosis and the plasma kininogen and low molecular weight kininogen antigen concentration in rabbits.

A decrease in trypsin-releasable kinin and in low molecular weight kininogen antigen concentrations was observed in plasma of rabbits with cholesterol-induced arteriosclerosis. In rabbits receiving normal diet for 30 days after 30 days of cholesterol almost complete normalization of the morphological status was observed, which was accompanied by normalization of plasma kinin concentration and by higher than normal concentration of kininogen antigen measured. These changes were not observed in animals receiving normal diet for 30 days after 60 days of cholesterol administration. No data were obtained suggesting a massive kinin release during induction of arteriosclerosis by experimental hypercholesteremia. The possibility of intense kinin formation during a period of repair of the morphological changes was discussed.