Search PubMed⌕ Search

Biomedical subjects

J Zielinski

Publications and source records attributed to J Zielinski.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Localized current field hyperthermia in carcinoma of the cervix: 3-D computer simulation of SAR distribution.

Software was developed for the 3D simulation of SAR distribution for a 500 kHz localized current field hyperthermia system to be used in patients with carcinoma of the cervix. This hyperthermia system was specifically designed for use with a modified Fletcher-Suit intracavitary applicator. It consists of software modules for data input, tetrahedral grid generation and a numerical calculation of SAR distribution using an adaptive, multilevel finite element code. The AVS (Advanced Visual System, Inc.) system was used for the visual presentation of the results. A quasi-static approach was employed for the determination of SAR distribution. Results of the performed numerical tests were presented and they showed an important, clinically relevant ability to obtain a selective power deposition. This selective power deposition depended on the applicator geometry, i.e. the distance between the components of a Fletcher-Suit applicator and their relative position and the use of different modes of excitation.

Brachytherapy↗
PubMedDate not supplied

Value of M-mode echocardiography in assessing pulmonary arterial pressure in patients with chronic lung disease.

Pulmonary valve echography was technically possible in 44 of 120 patients with chronic lung disease (CLD). Mean pulmonary arterial pressure (Ppa) was significantly correlated with right ventricular isovolumetric relaxation ratio (RVIRT/RVET) as derived from the movement of cusps in valves of the right heart (r = 0.842; p less than 0.001). Prolonged RVIRT was found in 52% of patients with Ppa greater than 20 mmHg and in all ten patients with Ppa greater than 35 mmHg. Other echographic signs, including abnormal right ventricular systolic time intervals (STI), 'a' wave amplitude, right to left ventricular ratio (RV/LV) and interventricular septum diastolic bulging (IVS-B), were less sensitive, but found more often; when higher Ppa was recorded at catheterization in a given patient (r = 0.869; p less than 0.001). Approximate echographic estimation of Ppa in patients with chronic lung disease is possible if right ventricular systolic and diastolic time intervals can be measured and if abnormalities in right ventricular dimensions, interventricular septum motion and pulmonary valve echogram are considered. In contrast to pulmonary fibrosis, technical problems in adequate visualization of right heart valves in chronic obstructive lung disease limit the use of M-mode echo assessment of Ppa to a clinically unacceptable 22% of subjects.

Adolescent↗
PubMedDate not supplied

Acute effects of almitrine infusion on pulmonary haemodynamics in normal man.

The aim of the study was to assess haemodynamic and ventilatory effects of almitrine infusion in normal subjects. Five males aged 19-49 years were studied using a floating catheter technique. The investigation consisted of three consecutive periods, lasting 20 min each. During the first one, the subject was allowed to settle down and baseline measurements were made. During the second period, a total dose of 0.33 mg X kg-1 of almitrine was infused over 20 min. During the third period, postinfusion effects were observed. Almitrine produced the expected increase in minute ventilation that was entirely due to that in tidal volume. Haemodynamic changes consisted of an increase in pulmonary vascular resistance and pulmonary arterial pressure. As there was no concomitant change in cardiac output or wedge pressure, the increase in pulmonary vascular resistance was apparently due to constriction of pulmonary muscular arteries. Pulmonary vasoconstrictor effects of almitrine were of short duration and were already tapering off before completion of the infusion, so that pulmonary arterial pressure was back to the baseline value 10 min after the infusion was completed.

Adult↗