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J Bednarek

Publications and source records attributed to J Bednarek.

At least 19 recordsLinked to original sources
PubMed2001

[The effect of changes in stroke volume on QT dispersion during long-term DDD and VVI pacing].

UNLABELLED: The aim of this study was to evaluate the alterations of stroke volume (SV) on the QT dispersion (QTD) as a result of different pacing modes (DDD, VVI) and programmed AV delays (AVD). MATERIAL AND METHODS: We studied 60 patients (pts) (22 F, 38 M) in mean age 67.5 +/- 7.5 yrs in whom DDD pacemakers were implanted due to complete atrioventricular block (AVB III degree). 10 pts had coronary artery disease (CAD)--"CAD" subgroup, 14 pts arterial hypertension (AH)--"AH" subgroup, 27 pts CAD and AH--"AH + CAD" subgroup. The control group consisted of 9 pts without structural heart disease, but with AVB III degree, paced in DDD mode. Previous myocardial infarction was recognised in 7 patients in "CAD" subgroup and in 7 patients in "AH + CAD" subgroup. Left ventricular hypertrophy was detected in 4 men in "AH" subgroup and in 8 patients in "AH + CAD" subgroup. In all cases basic rate of the pacemaker was programmed at 70/min. Resting ECG showed all atrial and ventricular complexes captured. AVD optimization was based on the measurements of SV by Doppler echocardiography. QT intervals (QT) were measured from 12-lead ECG at 50 mm/sec. speed. QTD was calculated as the difference between maximal and minimal QT. It was measured at optimal AVD (with highest SV--opt. DDD) and "unoptimal" AVD (unopt. DDD) programmed AV intervals and then in VVI mode (with lowest SV) after 24 hrs following reprogramming of the pacemaker. RESULTS: In the whole population, in DDD mode, we found a strong correlation between SV and QTD (r = -0.655; p < 0.01). In VVI mode SV was significantly lower than in unopt. DDD (78.7 ml vs 90.0 ml, p < 0.001) and QTD was significantly greater (74.3 ms vs 69.2 ms, p < 0.05). The modifications in AVD and conversion of pacing mode (VVI to DDD) leading to maximal SV resulted in decreased QT dispersion. The highest SV (128.9 ml at opt. DDD) and the lowest QTD (48.3 ms at opt. DDD) were seen in the controls, but changes in dispersion were the least and insignificant during different pacing modes. In CAD; AH + CAD pts, we observed the lowest SV (61.7 ml; 74.9 ml at VVI respectively) and the highest QTD (77.8 ms; 80.9 ms at VVI respectively). In these pts, the modifications of AVD and conversion of pacing mode (VVI to opt. DDD) leading to maximal SV (106.8 ml; 115.9 ml in CAD and AH + CAD pts, respectively) resulted in decreased QTD (53.9 ms; 56.6 ms, respectively). During DDD pacing there was significant correlation of QTD to SV (r = -0.680; r = -0.656, respectively). In CAD pts with myocardial infarction or in AH pts with LV hypertrophy the correlation of SV to QTD was stronger (r = -0.937, r = -0.886, p < 0.025, respectively). We didn't find the correlation in the control group (r = -0.318). CONCLUSIONS: Programming of different AVD and pacing modes significantly influences QTD in CAD and/or AH pts. QTD reflects hemodynamic status of these paced pts.

Adult↗
PubMed2001

[QT dispersion in DDD and VVI paced patients after myocardial infarction or with left ventricular hypertrophy].

The aim of this study was to assess the alterations of stroke volume (SV) on the QT dispersion (QTD) as a result of different pacing modes and programmed AV delays in patients (pts) after myocardial infarction (MI) or with left ventricular hypertrophy (LVH). We studied 14 MI pts (9 M, 5 F) in mean age 72.3 +/- 3.7 yrs (Group I) and 12 pts with LVH (7 M, 5 F) in mean age 67.3 +/- 5.9 yrs (Group II), in whom DDD pacemakers were implanted due to complete atrioventricular block. The control group (Group III) consisted of 9 pts without MI or LVH. In all cases basic rate of the pacemaker was programmed at 70/min. Resting ECG showed all atrial and ventricular complexes captured. AV delay optimization was based on the measurements of SV by Doppler echocardiography. QT intervals (QTi) were measured from 12-lead ECG at 50 mm/s speed. QTD was calculated as the difference between maximal and minimal QTi. It was measured at optimal (opt. DDD, with highest SV) and "unoptimal" (unopt. DDD) programmed AV intervals and then in VVI mode (with lowest SV) after following reprogramming of the pacemaker. In Group I and II, a strong correlation between SV and QTD was found (R = 0.816 and -0.897, respectively). In control group, it was insignificant (R = -0.339). In VVI mode SV was significantly lower than in unopt. DDD (in Mi pts: 56.1 ml vs 71.1 ml, respectively, p < 0.01; in LVH pts: 64.1 ml vs 96.7 ml, respectively, p < 0.005) and QTD was significantly greater (74.8 ms vs 66.8 ms, respectively, p < 0.005 and 70.0 ms vs 53.5 ms, respectively, p < 0.005). In LVH pts or MI pts programming of different AV intervals and pacing modes significantly influences QTD.

Aged↗
PubMed1996

[The role of prolonged cardiac pacing in management of secondary bradyarrhythmias based on personal experiences].

Three patients with bradyarrhythmia who were admitted to the Department for urgent pacemaker implantations are presented. The careful clinical evaluation revealed that these arrhythmias were remarkably secondary to underlying diseases (e.g. severe coronary heart disease, valvular defects). Surgical treatment applied in these cases (coronary bypass grafts, valve replacement) has resulted in successful outcome. We concluded that in some patients the pacemaker implantation alone, without heart surgery, would not be beneficial enough.

Aged↗
PubMed1994

Plasma ANP and cyclic GMP levels versus left ventricular performance at different AV delays in AV sequential pacing.

Eleven resting patients with an implanted DDD pacemaker were studied. After 30 minutes of AV sequential pacing at a rate of 80 beats/min with three consecutive atrioventricular delays (AVDs; 100, 150, and 200 msec) peripheral venous blood was drawn for further analyses by specific radioimmunoassays of atrial natriuretic peptide (ANP) and the ANP second messenger, cyclic guanosine monophosphate (cGMP). Relative changes in left ventricular (LV) stroke volume following alterations of AVD were assessed by means of pulsed-Doppler echocardiography through measurement of LV outflow time-velocity integrals (TVI). The optimal AVD (oAVD) was defined in individual patients as that which was associated with the greatest TVI and with improvement over both other AVDs of more than 4%. The oAVD was found in nine patients. For these nine patients no significant differences in either plasma ANP or cGMP between various AVDs were observed. However, we found such differences with respect to values measured at oAVD; both ANP and cGMP levels were lowest at oAVD. Pooling together the data obtained in 11 patients at three AVDs, a positive correlation between ANP and cGMP levels was found (r = 0.7, P < 0.0001, n = 33). Moreover, changes of plasma ANP and cGMP induced by every AVD increment of 50 msec were also correlated (r = 0.6, P < 0.01, n = 22). It is concluded that in AV sequential pacing at rest plasma ANP reaches minimal levels at the AVD, which provides the best LV performance. Although levels of cGMP changed in parallel with those of ANP, low relative values of cGMP differences may limit the usefulness of cGMP assays in optimization of the AVD.

Adult↗
PubMed1993

Expression of human thyroid peroxidase in the yeasts Saccharomyces cerevisiae and Hansenula polymorpha.

Saccharomyces cerevisiae and the methylotrophic yeast Hansenula polymorpha have been used to express both full-length and a large hydrophilic domain of human thyroid peroxidase (TPO). Expression of TPO in S. cerevisiae, using the natural signal sequence or the yeast alpha-mating factor (MF alpha) signal sequence, resulted in undetectable or very low levels of recombinant TPO production. However, TPO was expressed when the natural TPO leader sequence was replaced by the yeast STE2 signal sequence. This recombinant TPO reacted with both rabbit anti-human TPO polyclonal and mouse anti-human TPO monoclonal antibodies on Western blots. In the case of H. polymorpha, TPO expression was achieved when the natural TPO leader sequence was replaced by the MF alpha leader and the construct placed under the control of the methanol-regulated promoter from the methanol oxidase gene. The recombinant TPO produced in H. polymorpha reacted with both TPO polyclonal and TPO monoclonal antibodies. No TPO was produced when the signal sequence of SUC2 (invertase) or the TPO natural signal sequence was used to direct expression.

Amino Acid Sequence↗
PubMed1992

Steroid 21-hydroxylase is a major autoantigen involved in adult onset autoimmune Addison's disease.

An adrenal-specific protein reacting with autoantibodies in the sera of patients with adult onset Addison's disease has been purified from human adrenal glands. The protein, mol.wt. 55K, has the biochemical characteristics of steroid 21-hydroxylase and reacts on Western blots with rabbit antibodies to recombinant 21-hydroxylase. Absorption of the native human 55K adrenal protein with human adrenal autoantibodies prevented the subsequent reaction of the 55K protein with rabbit antibodies to 21-hydroxylase in Western blot analysis. In addition, human adrenal autoantibodies reacted with recombinant 21-hydroxylase expressed in yeast. These data indicate that the adrenal specific enzyme steroid 21-hydroxylase is a major autoantigen involved in adult onset autoimmune Addison's disease.

Addison Disease↗
PubMed1991

[Influence of radioactive contamination and iodine prophylaxis after the Czernobyl disaster on thyroid morphology and function of the Poznan region].

The radioactive contamination of Poznań Region was recognized after Chernobyl accident as average. The predicted values of minimal (inhalation) and maximal (inhalation and ingestion) committed dose equivalent to the thyroid varied from 2.5 (min) to 24.7 (max) mSv in different groups of adults and children. To follow up the results of iodine prophylaxis and some aspects of possible thyroid gland morphological and functional changes 11086 persons were carefully investigated clinically and biochemically. Among these 11086 persons were 42.6% males and 57.4% females both adults from 17 till 40 year and children up do 16 years. The following parameters were reviewed: pregnancy, time of residence in the region, thyroid abnormalities, family history concerning thyroid diseases, iodine intake in April and May 1986 with possible side effects, changes in the thyroid size observed before and after 1986, degree and kind of thyroid enlargement, serum concentration of T3, T4, TSH, ATMA and ATG titre and finally the effectiveness of thyroid blockade at 24, 48 and 72 h after ingestion of Lugol's solution. Side effects of the ingestion of potassium iodide from 30-70 mg were observed in 153 cases, 36 of them consulted medical doctors but in no case the side effects (dominated by vomiting) threatened the life. In the investigated group were 144 pregnant women. Majority, because 88% of them delivered the baby on or after time and 6.9% before time, 4.9% of natural abortions were noted but non artificial. In the group of children thyroid gland abnormalities before 1986 were reported in 3 cases in 23 after 1986 it is after Chernobyl accident. This information is interesting but needs more precise analysis of different dependencies occurring. The data obtained indicated the existence in Poznań. Region the goiter endemy because 27.5% of investigated children and adults had goiter classified as grades O-B, I, II and III. The elevation or diminution of T3 values were noted in 1164 cases, for T4 in 418 cases and for TSH in 1412 cases. The presence of antimembrane and antithyroglobulin antibodies were observed in 303 cases. All persons with changes observed in thyroid morphology and function are periodically controlled and the results will be published separately. The investigations performed and results presented concern the early aspects of radioactive contamination and effects of iodine prophylaxis. The answer regarding late effects including thyroid cancer needs further multi year studies for which the clinical material investigated in different parts of Poland and well documented should be used as model group for further periodical studies.

Adolescent↗
PubMed1986

Sex dimorphism in the thyroid gland. IV. Cytologic aspects of sex dimorphism in the rat thyroid gland.

This study was designed to explain whether the sex-dependent differences in the structure of the thyroid gland of adult male and female rats depend on quantitative or qualitative changes in the thyroid follicular cells. Absolute thyroid gland weight was similar in male and female rats, but its relative weight was markedly higher in females however. Volume fractions of epithelium and stroma were higher and that of colloid lower in male than in female rats and the epithelium/colloid ratio was higher in the males. Also absolute the volumes (in mm3) of epithelium and stroma were higher in the males; the thyroid gland of females contained more colloid. The average volume of a thyroid follicular cell, estimated by stereology, was higher in males than in females, although the thyroid gland contained similar numbers of follicular cells in both sexes. Also, thyroid glands from both male and female rats contained a similar DNA quantity. Results of the present study show that the sex dimorphism in the rat thyroid depends upon a difference in the mean volume of thyroid follicular cells, with males having larger cells than females. However, in both sexes the thyroid gland contains a similar quantity of these cells.

Animals↗