[Tachycardia-induced cardiomyopathy]. / Arytmogenna kardiomiopatia rozstrzeniowa.

Dilated cardiomyopathy induces circulatory insufficiency with poor prognosis. Persistent tachyarrhythmias may be the cause of this disease. At particular high risk for heart damage and insufficiency are young people and children. The group of most dangerous arrhythmias consist of: incessant tachycardia in patients with preexcitation syndrome and supraventricular tachyarrhythmias (atrial flutter and fibrillation, ectopic atrial tachycardia) with high rate of ventricles. The result of arrhythmias is dilatation of the heart and thinness of ventricular walls with hemodynamic disorders. The effective therapy of arrhythmias--ablation of the accessory pathway in patients with pre-excitation syndrome or reversion to sinus rhythm (pharmacological or electric cardioversion) in patients with atrial fibrillation and flutter, often leads to normalisation of heart ejection function and diameter. Therefore it exist important question: is dilated cardiomyopathy the cause or consequence of tachyarrhythmias? Causative antiarrhythmic therapy in these second cases gives a possibility to improve the prognosis in patients with such a disease.

Three methods for investigating, assessing and supporting the normal and pathological gait and manipulation activity.

Three methods to describe biped locomotion as well as manipulation activity are presented. Methods using so-called couple oscillators as rhythm generators are described. Based on a mathematical model, results of computer simulation of biped locomotion are presented. An indices method of assessing human gait for both normal and pathological cases was proposed and tested. The results showed that it is relatively easy to distinguish different gaits by using this method. This method was tested in clinical conditions. The third method deals with the problem of supporting the lost function of prehension movements. Implanted stimulators on the nerves combined with external orthoses were used. The clinical results show that these methods have practical advantages.

[Use of intravascular ultrasonography (IVUS) for diagnosis and treatment of coronary artery disease--case report]. / Zastosowanie ultrasonografii wewnatrznaczyniowej (IVUS) w diagnostyce i leczeniu choroby niedokrwiennej serca--opis przypadku.

One of the additional methods of coronary artery assessment is intravascular ultrasound (IVUS). Contrary to coronary angiography this relatively new technic provides new information including precise calculations of stenosis degree, morphology of atheromatous plaque and differentiation of its structure. Coronary angiography was performed in 54 years old male patient with unstable angina, revealing 99% stenosis in distal RCA. Discrepancy between clinical presentation and angiographic findings and exercise test resulted in performing IVUS of LAD. Angiographically clear LM and LAD were found to be narrowed 52% and 58% on IVUS. Subsequent CABG resulted in symptoms withdrawal and increase of physical tolerance. Exercise test after CABG did not reveal ischaemia in area of LCA at 10 METs. IVUS is found to be an important technic in assessment of silent or ambiguous lesions and in many cases allows to choose the optimal method of treatment of coronary artery disease.

Coupled oscillators utilised as gait rhythm generators of a two-legged walking machine.

The gait of current two-legged walking machines differs from that of humans, although the kinematic structures of these machines' legs frequently imitate human limbs. This paper presents a method of generating the trajectories of hip and knee joint angles resulting in a gait pattern similar to that of a human. For this purpose the solutions of coupled van der Pol oscillator equations are utilised. There is much evidence that these equations can be treated as a good model of the central pattern generator generating functional (also locomotional) rhythms in living creatures. The oscillator equations are solved by numerical integration. The method of changing the type of gait by changing appropriate parameter values in the oscillator equations is presented (change of velocity and trajectory of leg-ends). The results obtained enable enhanced control of two-legged walking systems by including gait pattern generators which will assume a similar role to that of biological generators.

[Cardiomyopathy in diabetes. Ultrastructural examinations]. / Uszkodzenie serca w cukrzycy. Badania ultrastrukturalne.

The functional and morphological changes in myocardium of diabetic patients is caused by diabetic macroangiopathy, diabetic microangiopathy, autonomic neuropathy and metabolic disorders. Mechanism of these changes in the course of diabetes is not fully known. To determine whether there are myocardial ultrastructure differences between patients with diabetic cardiomyopathy (normal coronary angiograms) and diabetic patients with coronary artery disease, electron microscopy examination were performed of 70 sections received from seven biopsied patients (1F, 6M), average age 53 years (range: 42-60) with diabetes type II WHO (group A) without clinical evidence of prior coronary artery disease and hypertension, and 100 sections from 10 patients (2F, 8M), average age 54 years (range: 42-65) with diabetes and coronary atherosclerosis. These patients had clinical evidence of heart failure and were submitted to bypass-graft operations (group B). Endomyocardial biopsy tissues were obtained from the right ventricle without complications either during or after the procedure. Obtained biopsy specimens were fixed in 3% glutaraldehyde stabilized with 1M cacodylate buffer at pH 7.4, postfixed in 1% OsO4 on cacodylate buffer. The materials were then dehydrated and embedded in epon. The Irvin-Fischer test for statistical analysis was used. A p value < 0.05 was considered significant. The presence of focal mild loss of myofibrils (+) was statistically more frequent in the patients in A group (p < 0.05). It was found in 86% (6/7) of cases in A group, while in the B group was observed in 20% of (2/10) cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of Vacuolar pH of Plant Cells: I. Isolation and Properties of Vacuoles Suitable for P NMR Studies.

For the first time, the (31)P nuclear magnetic resonance technique has been used to study the properties of isolated vacuoles of plant cells, namely the vacuolar pH and the inorganic phosphate content. Catharanthus roseus cells incubated for 15 hours on a culture medium enriched with 10 millimolar inorganic phosphate accumulated large amounts of inorganic phosphate in their vacuoles. Vacuolar phosphate ions were largely retained in the vacuoles when protoplasts were prepared from the cells and vacuoles isolated from the protoplasts. Vacuolar inorganic phosphate concentrations up to 150 millimolar were routinely obtained. Suspensions prepared with 2 to 3 x 10(6) vacuoles per milliliter from the enriched C. roseus cells have an internal pH value of 5.50 +/- 0.06 and a mean trans-tonoplast DeltapH of 1.56 +/- 0.07. Reliable determinations of vacuolar and external pH could be made by using accumulation times as low as 2 minutes. These conditions are suitable to follow the kinetics of H(+) exchanges at the tonoplast. The (31)P nuclear magnetic resonance technique also offered the possibility of monitoring simultaneously the stability of the trans-tonoplast pH and phosphate gradients. Both appeared to be reasonably stable over several hours. The buffering capacity of the vacuolar sap around pH 5.5 has been estimated by several procedures to be 36 +/- 2 microequivalents per milliliter per pH unit. The increase of the buffering capacity due to the accumulation of phosphate in the vacuoles is, in large part, compensated by a decrease of the intravacuolar malate content.