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Biomedical subjects

P Lewandowski

Publications and source records attributed to P Lewandowski.

At least 19 recordsLinked to original sources
PubMed2000

Risk evaluation of ventricular tachycardia using wavelet transform irregularity of the high-resolution electrocardiogram.

A new method for analysis of high-resolution ECG signals using a wavelet transform based on a modified Morlet function is presented. A polynomial filter is used to reduce low-frequency, high-amplitude noise components in the analysed signals. The method is tested on test ECG signals with simulated late potentials and finally verified on two post-infarction patient (PP) groups: 62 PPs with ventricular tachycardia and 44 PPs without arrhythmia. A new quantitative parameter, the irregularity factor, is proposed for discrimination between the study groups. The results show a significant difference in the parameter values for tachycardia patients compared with those for patients without arrhythmia. The sensitivity of the proposed method is 85%, and the specificity is 93%.

Adult↗
PubMed2000

Impact of obesity and leptin treatment on adipocyte gene expression in Psammomys obesus.

We examined the effects of leptin treatment on the expression of key genes in adipocyte metabolism in Psammomys obesus (P. obesus), a polygenic rodent model of obesity. Lean and obese P. obesus were given three daily intraperitoneal injections of either saline or leptin (total of 45 mg/kg per day) for 7 days. In lean animals, leptin treatment led to reductions in food intake, body weight and fat mass. Pair-fed animals matched for the reduction in food intake of the lean leptin-treated animals demonstrated similar reductions in body weight and fat mass. In obese P. obesus, leptin treatment failed to have any effect on body weight or body fat mass, indicating leptin resistance. Lipoprotein lipase, hormone-sensitive lipase and peroxisome proliferator activated receptor gamma 2 mRNA levels were significantly reduced in lean leptin-treated animals, whereas pair-fed animals were similar to lean controls. Uncoupling protein 2 and glycerol phosphate acyltransferase were also reduced in the lean leptin-treated animals, but not significantly so. Obese animals did not show any gene expression changes after leptin treatment. In conclusion, high circulating concentrations of leptin in lean P. obesus resulted in decreased gene expression of a number of key lipid enzymes, independent of changes in food intake, body weight and fat mass. These effects of leptin were not found in obese P. obesus.

Adipocytes↗
PubMed1999

Leptin resistance in a polygenic, hyperleptinemic animal model of obesity and NIDDM: Psammomys obesus.

OBJECTIVE: To investigate the effects of leptin administration to Psammomys obesus, a polygenic animal model of obesity and type 2 diabetes mellitus. DESIGN: Longitudinal intervention study utilising three separate leptin treatment protocols lasting 7-14 d. MEASUREMENTS: Body weight and food intake were measured daily, body fat and muscle content were estimated by carcass analysis on completion of the study. Blood glucose, plasma insulin, leptin, triglycerides and cholesterol were measured at baseline and twice each week during the study. RESULTS: Relatively high doses of leptin were required to significantly reduce food intake and body fat content in lean Psammomys obesus, but had no discernible effect on their obese littermates. CONCLUSION: As a species, Psammomys obesus appear to be relatively insensitive to the effects of leptin administration, compared with other rodents. Obese Psammomys obesus are leptin resistant relative to their lean littermates.

Animals↗
PubMed1999

Spectral analysis of laser-Doppler perfusion signal measured during thermal test.

The method of spectral analysis of laser-Doppler perfusion signal measured during thermal test is proposed. During three 20 min phases with 40, 5, and 40 degrees C of thermal test laser-Doppler perfusion signal was recorded. For each signal phase frequency spectra were calculated using the FFT method. Quantitative parameter Spectral Factor for results evaluation was proposed. In total 94 patients were measured: 69 with Raynaud's phenomenon and 25 normal subjects. Additionally in 18 Raynaud's patients the influence of Nifedipine was studied. Results suggest that proposed parameter is able to differentiate between Raynaud's patients and normal subjects and that is useful for evaluation of Nifedipine effectiveness. However, further studies are needed to improve the method to differentiate between primary and secondary Raynaud's patients.

Adult↗
PubMed1998

[Needle testicular biopsy in the diagnosis of male infertility].

OBJECTIVES: Evaluation of testicular tissue is very important diagnostic procedures in cryptozoospermia and azoospermia. It is verified the patient for treatment (stimulation spermatogenesis), for micromanipulation ICSI or for insemination donor semen procedure. Surgical biopsy is very popular between andrologist and urologist, but needle biopsy seems to be easier and safer. DESIGN: The authors present their experience with needle testicular biopsy during the diagnosis patients with azoospermia or cryptozoospermia and the men with paraplegia after trauma and without ejaculation. MATERIAL AND METHODS: The study group included 63 biopsies in 58 men with azoospermia and severe oligoasthenozoospermia (cryptozoospermia) and 2 with paraplegia. The specimens were taken from 125 testes under general anesthesia (i.v-Diprivan, Propofol, Zeneca and Fentanyl) using biopsy needle from Hepafix B. Braun Melsungen, Germany. All procedures were performed as a day case. RESULTS: In 95% specimens were adequate for histopathological investigations and for planning the treatment. Only one complication (0, 8%) -small haematoma testis was observed. CONCLUSIONS: The needle biopsy of testicular tissue is sufficiency in histopathological examination, safe for patients and easy for urologists. The total cost is much more lower than cost of surgical biopsy.

Adult↗
PubMed1998

[Percutaneous sperm retrieval for ICSI procedures in men with obstructive azoospermia: ICSI-PESA and ICSI-TESE micromanipulation: our experience].

OBJECTIVES: The sperm retrieval for ICSI procedures is possibly using following procedures: ejaculate sperm, epididymal sperm obtained by microsurgical aspiration or percutaneous puncture and testicular sperm that are obtained by surgical excision or percutaneous biopsy. Percutaneous techniques seem to be rather simple and effective procedures. DESIGN: The authors present their own experiences with percutaneous sperm retrieval for micromanipulation ICSI from the epididymis (ICSI-PESA) and from the testicular tissue (ICSI-TESE) in men with obstructive azoospermia and with reactive impotence. First time in Poland ICSI-PESA was done on April 11, 1996 in Private Infertility Center "Novum", Warsaw. MATERIAL AND METHODS: From April 1996 to the end of January 1998, 10 ICSI-PESA procedures (in 9 couples) and 8 ICSI-TESE (in 6 couples) were performed. In one case ICSI-PESA was performed in man with psychological inability of masturbation during his wife's IVF protocol. All procedures were performed as the day case urology, under general anesthesia. The fine needles No 6 in PESA or biopsy needle from Hepafix Set B. Braun in TESE were used. The therapy of antibiotic and common analgesic drug was used routinely after puncture. RESULTS: The effectiveness of obtaining sperm for micromanipulation were 100% ICSI-PESA and 75% ICSI-TESE. The pregnancy rate in PESA was 50% and 5 healthy children were born. In TESE only 1 woman (17%) was pregnant, but early spontaneous miscarriage was reported. No surgical and anesthesiological complications were noticed. CONCLUSIONS: Obtaining sperm for micromanipulation ICSI using percutaneous epididymal puncture or testicular tissue needle biopsy seems to be effective and safe for patients with obstructive azoospermia or reactive impotence.

Arterial Occlusive Diseases↗
PubMed1997

Leptin and the development of obesity and diabetes in Psammomys obesus.

The recently discovered ob gene and its circulating product, leptin, may be critical factors in the control of energy balance. Recent studies in ob/ob mice, which lack circulating leptin, have shown dramatic reductions in food intake and bodyweight after leptin treatment. In addition, studies in both humans with obesity and animal models of obesity have demonstrated hyperleptinemia. Here, we report a longitudinal study examining changes in circulating leptin during the development of obesity and diabetes in Psammomys obesus. Over the 8 weeks of the study, lean animals increased their bodyweight by 154% and leptin levels remained essentially unchanged. In contrast, animals that developed obesity (223% increase in bodyweight), hyperglycemia, and hyperinsulinemia also developed hyperleptinemia between 4 weeks and 8 weeks of age. These results demonstrate that the development of hyperleptinemia is associated with the development of obesity and subsequent metabolic abnormalities.

Adipose Tissue↗
PubMed1993

[Usefulness of a gel with a new composition for gonioscopy and laser microsurgery].

A newly composed gel was examined with a view of determining its usefulness for gonioscopy and laser microsurgery. It was found, that it did not exert any adverse effect on ocular tissue, it displayed perfect transparency and proper consistency facilitating manual operation. Experimental procedures confirmed its clinical usefulness.

Gels↗
PubMed1993

[Studies of releasing rate of pilocarpine hydrochloride from hydrogel eye ointments].

The aim of the study was to evaluate the usefulness of hydrophilic base with pilocarpine hydrochloride. Comparisons were made between releasing rate of pilocarpine hydrochloride from hydrophilic and lipophilic bases into water and artificial tears. It was found that pilocarpine hydrochloride was released in the amount 30-40 times greater from hydrogel bases compared to lipophilic. The releasing rate of drugs from hydrogel ointments increases with the increased colloid concentration and with decreased of drug concentration in the base.

Ointment Bases↗
PubMed1992

The relation between the sagittal and transversal diameters in eyes with retinal detachment.

Using A-mode ultrasonography, the axial length and the width (transversal or equatorial diameter) of both eyes--fellow and affected--have been measured in patients with retinal detachment. For comparison, the same measurements have been performed in healthy controls. The patients have been divided into different groups. It was found that there are some changes in the relation between the axial length and the width of the eyes in patients with retinal detachment, according to the comparison with healthy people, in most cases.

Anthropometry↗
PubMed1991

[Pemphigoid as a cause of marked impairment of visual acuity].

Among 11 patients aged 9-79 years with diagnosed pemphigoid 5 were men and 6 women. Three persons exhibited only some conjunctival irritation and conjunctival adhesions, the remaining 8--besides some shallowness of the fornices--showed also corneal changes. Six patients showed signs of the dry-eye syndrome and 3--symptoms of secondary glaucoma. General treatment (Avlosulfon, encorton) was applied in 8 patients.

Adolescent↗
PubMed1988

Evaluation of a prescreening blood donor program for prevention of perinatal transfusion-acquired cytomegalovirus (CMV) infection.

The purpose of this study was to evaluate the efficacy of a prescreened CMV seronegative blood donor group in preventing transfusion-acquired CMV infection in premature infants in the perinatal period. Group 0 donors with known CMV seronegative status were recruited to supply blood to the neonatal intensive care nurseries. One hundred and twenty-seven low birth weight infants born of CMV seronegative mothers remained seronegative when blood for transfusion was screened for CMV antibody. Twenty two infants shared six units of CMV seropositive blood due to technical errors or poor sensitivity of the test kit in the initial phase of the study. Fifteen of these patients were in the study group. One infant died of immaturity at four weeks of age and two of the remaining 14 showed asymptomatic CMV infection. Another infant who received granulocyte concentrates from CMV seropositive donors had symptomatic CMV infection. Throughout the 24 month study period, blood supply to the ICN was adequate and timely. The donor seroconversion rate was 0.7% per annum. Only one infant was exposed to the risk of CMV infection due to donor seroconversion. We conclude that the prescreening donor program is a sensible and efficient approach for providing CMV seronegative blood in neonatal transfusion therapy.

Antibodies, Viral↗
PubMedDate not supplied

Effectiveness of high resolution ECG spectral analysis in discrimination of patients prone to ventricular tachycardia and fibrillation.

INTRODUCTION: To improve the diagnostic power of high resolution electrocardiography for discriminating patients at risk of ventricular arrhythmias, new methods based on spectral analysis have been used in recent years. The purpose of this study was to evaluate the effectiveness of these methods for predicting the risk of ventricular tachycardia and ventricular fibrillation in patients after myocardial infarction. MATERIAL AND METHODS: High resolution ECG were recorded in 129 post-infarction patients and 23 healthy volunteers. Of the post-infarction patients: 62 presented with ventricular tachycardia, 23 with ventricular fibrillation, while 44 had no clinically relevant arrhythmias. The ECG signals were recorded in three orthogonal X, Y, Z leads and averaged using cross-correlation method. Spectral analysis was performed by fast Fourier transform and the parametric modeling method with autoregressive model. Spectral analysis data were evaluated quantitatively by computing normality factor for FFT and spectral factor for AR. RESULTS: Both methods were found to be useful for evaluating the risk of arrhythmias. The sensitivity of ventricular tachycardia risk evaluation was higher (81%--FFT, 73%--AR) than that of evaluating the risk of ventricular fibrillation (30%--FFT, 48%--AR). The specificity in post-infarction patients without arrhythmias (93%--FFT, 84%--AR) was as high as that in healthy subjects (96%--FFT, 87%--AR). CONCLUSIONS: Spectral analysis of HRECG is an effective method for evaluating the risk of VT and VF in patients after myocardial infarction.

Adult↗
PubMedDate not supplied

[Lipid disturbance of cell membranes in the etiopathogenesis of schizophrenia and affective disorders].

The authors present information on the key role of lipid disturbances (mainly phospholipids) of neural membranes in the etiopathogenesis of schizophrenia and affective disorders. Current theories on membrane phospholipid disturbances in the etiopathogenesis of schizophrenia and affective disorders are connected to the idea that the primary metabolic disorder in both these disorders is due to the altered activity of phospholipase AZ, which in turn brings about disturbances in other lipid elements. Especially the functional insufficiency of some necessary fatty acids, as well as disturbed prostaglandin secretion has been shown in these disorders. In the recent years evidence has been collected on the action of pharmacologic substances used in these disorders on the lipid enzyme metabolism.

Cell Membrane↗
PubMedDate not supplied

[Evaluation of pupillary reaction to light flash in patients with retinitis pigmentosa].

Twenty four patients with retinal pigment dystrophy were subjected to examination of pupillary reaction. Evaluated was the amplitude of pupillary reaction on a standard light flash. The results received were compared with the field changes. It was noted that the amplitude is diminished depending on the changes in the visual field.

Adolescent↗