Search PubMed⌕ Search

Biomedical subjects

J Sadowski

Publications and source records attributed to J Sadowski.

At least 55 records · Page 3Linked to original sources
PubMed1996

Access to rat kidney with minimal anesthesia and surgery: a new experimental model.

Chronic surgical explantation of the left rat kidney out of the abdominal cavity under the flank skin enabled easy access to the organ and ipsilateral urine collection under light chloralose anesthesia without virtually any surgical intervention. The glomerular filtration rate, urine flow and osmolality, sodium excretion, and medullary tissue hypertonicity were similar in the explanted and in the contralateral kidney, whereas p-aminohippurate clearance was 14% lower. The function of the explanted kidney was also compared with that of the kidney acutely exposed in rats under thiobutabarbital anesthesia and rendered euvolemic by isoncotic albumin infusion. Again, in both preparations renal function was comparable except that over time urine osmolality remained stable in the former and fell from 1,385 +/- 195 to 835 +/- 167 mosmol/kgH2O (P < 0.02) in the latter, indicating deterioration of urine concentration. Laser-Doppler probes could be easily applied in the explanted kidney to measure cortical and medullary blood flow. The new experimental model offers some advantages, both over studies using conscious rats and over experiments involving deep anesthesia and acute surgery.

Anesthesia↗
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↗
PubMed1996

Successful full-term pregnancy in a patient three and a half years after a heart transplant.

The patient is a 28 year old woman who received a heart transplant in 1992 secondary to hypertrophic cardiomyopathy with unremarkable post-operative course. In the period immediately post transplantation the patient was on a four-drug immunosuppressive regimen which was subsequently changed to standard three-agent therapy. This therapy was continued until the patient became pregnant. In the first trimester only Cyclosporine (CsA) was used, and thereafter, the patient was continued on the previous three agent regimen. Toward the end of pregnancy a rise in systolic pressure was observed, but the child was delivered by spontaneous vaginal delivery without complications in the 38th week of pregnancy. The newborn weighed 3320 g and was in good health. A sharp fall in the newborn CsA blood levels was observed post delivery reaching zero level on the third day of life. At the present time, both mother and baby are in good health, 6 weeks after delivery.

Adult↗
PubMed1995

Modulation of renal medullary ionic hypertonicity by prostaglandins: data from tissue admittance studies in the rat.

1. Modulation of the cortico-papillary electrolyte gradient by prostaglandins (PG) was studied in the kidney of anaesthetized rats. The intrarenal PG activity was varied by synthesis blockade with indomethacin (Ind) or meclophenamate (Me) and by intrarenal infusion of prostaglandin E2 (PGE2). 2. The interstitial electrolyte concentration in the medulla was continuously recorded in the kidney in situ as tissue electrical admittance (reciprocal impedance); the total renal blood flow (RBF), inulin clearance (Cin) and renal excretion were measured simultaneously. 3. Indomethacin and Me (15 mg kg-1 h-1) increased tissue admittance 15-20% in the inner and 12-15% in the outer medulla (P < 0.001) whereas PGE2 (300 ng kg-1 min-1) decreased admittance 14 and 8%, respectively (P < 0.01). 4. Renal blood flow and Cin were not affected by intrarenal PG activity changes. There was an increase in urine concentration after PG blockade and a delayed decrease after PGE2 infusion. 5. A joint analysis of the dynamics of medullary tissue admittance, renal haemodynamics and renal excretion provides evidence that PGs modify the medullary ionic hypertonicity by affecting NaCl transport in the ascending limb of the loop of Henle.

Analysis of Variance↗
PubMed1995

Glucagon increases medullary interstitial electrolyte concentration in rat kidney.

In anesthetized rats, tissue electrical admittance of the inner medulla (a measure of total ion concentration in the interstitium), medullary blood flow (laser Doppler technique), and renal clearances were measured simultaneously before and during i.v. infusion of glucagon at 110 and 330 ng.min-1.kg-1 body weight. Admittance increased modestly, 5.4% after a large glucagon dose (p < 0.01), whereas medullary blood flow was stable. Glomerular filtration rate increased transiently and then fell during high-dose glucagon infusion. The increase in tissue electrolyte (mostly NaCl) concentration in the medulla observed with stable medullary blood flow and decreasing glomerular filtration rate indicates that stimulation of NaCl reabsorption in the medullary ascending limb of Henle's loop by glucagon was the mechanism underlying augmentation of medullary ionic hypertonicity. This suggests that glucagon can contribute to the urine concentration process.

Animals↗
PubMed1994

Role of vasopressin V2 receptors in modulation of the renal cortico-papillary NaCl gradient.

In order to examine if modulation by vasopressin of NaCl transport in Henle's loops (via V2 receptors) can significantly modify medullary ionic hypertonicity, the effects of stimulation or inhibition of these receptors were studied in anaesthetized Wistar rats. Total electrolyte concentration in the medullary interstitium was continuously measured as tissue admittance (reciprocal impedance), using needle electrodes recording from the inner and outer medulla of the in situ kidney. Deamino-[Cys1, D-Arg8]vasopressin (dDAVP], a V2 agonist, infused i.v. at 7.5 ng.min-1.kg-1, significantly increased admittance by 9% and 8% in the inner and outer medulla, respectively. A slightly pressor i.v. infusion of natural arginine vasopressin (AVP) induced pressure natriuresis and did not affect medullary electrolyte concentration. Inhibition of V2 receptors with [d(CH2)5, D-Phe2, Ile4]-AVP, infused i.v. at 133 micrograms.h-1 kg-1 in indomethacin-treated rats, decreased admittance (significant in the inner medulla). Neither of the three agents used caused significant changes in the renal blood flow (RBF) or clearance of inulin (Cin). The demonstration that changing activity of V2 receptors affects the corticopapillary NaCl gradient indicates that, at least in rodents, stimulation of loop salt transport by AVP may represent an additional mechanism enhancing urine concentration.

Absorption↗
PubMed1994

[Usefulness of imaging methods in the diagnosis of aortic dissecting aneurysms].

Based upon personal experience and literature the authors briefly discuss the usefulness of arteriography, ultrasonography, CT and MR in the diagnosis of aortic dissecting aneurysms. In the diagnostic algorithm concerning aortic dissection type I and II acc. DeBakey, the initial diagnostic method should be echocardiography, followed by CT or MR or eventually aortography. In the case of type III aortic dissection the authors recommend transesophageal echocardiography and CT or MR or eventually aortography as the last examination.

Aortic Dissection↗
PubMed1994

[CT picture of aortic prosthetic grafts and homografts in patients with aortic dissection treated surgically].

A group of 22 patients with aortic dissection (type I, II and III acc. to De Bakey's classification) and surgically implanted aortic prosthetic grafts was studied, CT scanning is useful in visualizing aortic prosthetic grafts. Dacron vascular prostheses, initially clearly visible give weaker shadows with time, whereas homografts with time, contrast with increasing intensity, with the background on CT scans, due to calcifications.

Aortic Dissection↗
PubMed1993

Vitamin K1 metabolism and the production of des-carboxy prothrombin and protein C in the term and premature neonate.

This study investigated the incidences of undercarboxylated (protein induced by vitamin K absence: PIVKA) prothrombin and protein C in 496 neonates across a wide range of gestational ages. These findings are related to vitamin K1 levels (an indicator of cofactor availability) and vitamin K1 epoxide levels (a measure of the efficiency of the hepatic vitamin K cycle). PIVKA protein C was present in at least trace amounts in 27% of infants; whereas, PIVKA prothrombin was present in 7% of infants. PIVKA prothrombin and protein C were present at high plasma concentrations in 2% to 3% of term and preterm neonates and both PIVKA protein C and prothrombin increased with gestational age. Despite elevated plasma concentrations of PIVKA protein C and diminished levels of normally carboxylated protein C, clinical thrombosis was not observed. The mean (+/- SD) vitamin K1 level in the study population was 0.009 +/- 0.02 nmol/L (adult reference interval: 0.3 to 2.6 nmol/L) with no clear relationship between vitamin K1 levels and production of PIVKA protein C or prothrombin. By comparison with adults, the epoxide form of the vitamin comprised an abnormally high proportion of total vitamin K1; this suggests possible inefficiencies in hepatic reductase cycling.

Biomarkers↗
PubMed1993

Sex differences in control of renal outer medullary circulation in rats: role of prostaglandins.

A calibration technique was developed to quantify blood flow changes in the renal cortex and outer medulla in rats using platinum needle electrodes sensing partial pressure of locally generated hydrogen. Measurements were made in male and female rats to investigate sex differences in the humoral control and autoregulation of regional renal circulations. In males, both cortical and outer medullary blood flows were efficiently auto-regulated above an arterial pressure of 100 mmHg. The converting-enzyme inhibitor quinapril increased blood flow by 20% in both kidney zones, and inhibition of prostaglandin synthesis by indomethacin did not change the flow. In females, similar results were obtained only for the cortex; the medulla had a different response pattern. The blood flow was not autoregulated in the experimental pressure range up to 120 mmHg; quinapril did not change the flow, but indomethacin decreased the flow by 16% and at the same time restored its autoregulation capacity. We conclude that: 1) the medulla of female rats has a high basal level of vasodilator prostaglandins, which interferes with blood flow autoregulation in this kidney area, and 2) medullary flow in female rats is little affected by endogenous angiotensin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1993

[Diagnostic difficulties in a 32-year old patient with cardiac tamponade].

At present the most frequent cause of cardiac tamponade is neoplasma. A case of a 32-year-old male with recurrent cardiac tamponade caused by pericardium mesothelioma is described. Despite advanced neoplastic process in the pericardium, pleura and mediastinum, neither radiologic examinations of the chest, echocardiography, nor repeated cytologic examination of the pericardial exudate, could establish the etiology of the tamponade. Only after a pericardial window had been performed was it possible to: 1) establish the diagnosis and introduce causal treatment; 2) prevent recurrence of the tamponade; 3) perform cytoreduction of the tumor. It seems that in cases of chronic exudative pericarditis of unknown cause it is proper to perform an early pericardial window as a diagnostic and therapeutic procedure.

Adult↗
PubMed1992

Conductance studies of rat renal medulla for rapid estimation of extracellular electrolyte concentration.

A method is described for estimation of tissue extracellular electrolytes in fresh excised rat renal medulla on the basis of its electrical conductance. The inner medulla was placed between two standard flat electrodes and the conductance was measured at a frequency of 3.5 kHz. The data were corrected for the surface area and thickness of the tissue fragment. The standard conductance so determined clearly correlated with total electrolyte concentration, and Na+ and 2(Na+ + K+) concentrations in the whole tissue (r = 0.84, 0.81 and 0.77, respectively; P < 0.001). The method enables a rapid and simple estimation of medullary extracellular electrolytes, a variable that is physiologically more meaningful than whole tissue electrolyte concentration.

Animals↗
PubMed1991

Tissue PH2 measurement for continuous estimation of blood flow changes in rat kidney cortex and medulla.

A method is described for estimation of local blood flow changes in the renal cortex and medulla, based on continuous polarographic measurement of tissue pressure of electrochemically generated hydrogen (PH2). The technique was used in anaesthetized female Wistar rats. The changes in cortical PH2 were negatively correlated with those in flow velocity in the renal artery (Doppler probe). To evaluate the method, PH2 responses to a reduction of renal perfusion pressure (RPP) and to angiotensin II were examined. RPP reduction from 130 mmHg to 104 mmHg increased the cortical PH2 by 3.5% and medullary PH2 by 6.9% (difference significant at P less than 0.02). With RPP reduction from 113 mmHg to 76 mmHg the values were 6.9% and 11% respectively (difference significant at P less than 0.001). Angiotensin II infusion increased cortical PH2 by 8.7% and medullary PH2 by 4.1% (difference significant at P less than 0.005). It is concluded that the method enables continuous estimation of blood flow changes in the renal cortex and medulla.

Angiotensin II↗
PubMed1991

Independent Regulatory Aspects and Posttranslational Modifications of Two beta-Amylases of Rye : Use of a Mutant Inbred Line.

We have examined the occurrence/disappearance, tissue location, and posttranslational modification of beta-amylase proteins in rye (Secale cereale L.) kernels at three physiological stages (development, maturity, germination) with a normal inbred line and a mutant line exhibiting a high but incomplete beta-amylase deficiency. This deficiency corresponds to a lack of accumulation of beta-amylase activity in the endosperm and does not affect the level of activity in the outer pericarp and green tissues as compared to the normal line. Two antigenically related but distinct beta-amylases (I and II) were detected in the normal line (II being the major constituent) and only one (I) in the mutant line. I and II display very similar electrophoretic polymorphism. In both lines, I appears to be ubiquitous, although it disappears from the outer pericarp during ripening. Antigen II was present only in the normal line and appears to be specific for the endosperm and perhaps for the maternal green tissues of the seed. Posttranslational modifications occurring during germination, which are mimicked by the action of papain, affect II but not I. The two groups of beta-amylases are discussed in relation to recent reports indicating the presence of two types of beta-amylase with different functions and gene loci in barley and wheat.

Journal Article↗
PubMed1991

[Constrictive pericarditis].

Etiology of constrictive pericarditis is diversified. In recent years the role of viral and iatrogenic factors (X-ray therapy, cardiac surgery) has increased. Clinical manifestations, including subjective complaints, resemble those in congestive heart failure although the mechanism of hemodynamic disorders is different--namely impairment of ventricular filling and diastolic performance. One encounters major difficulties while differentiating constrictive pericarditis from restrictive cardiomyopathy. In some patients conservative treatment is effective, in a majority of them surgical operation, pericardiectomy is the treatment of choice.

Adolescent↗
PubMed1990

Ion concentration and haematocrit as determinants of impedance in an erythrocyte suspension model of renal medullary tissue.

In order to analyse the respective roles of ion concentration and fractional volume of the interstitial compartment as determinants of the impedance, Z, of renal medullary tissue, a model was needed in which both these factors could be varied independently. An array of blood cell suspensions ions in saline (different haematocrit values and different NaCl concentrations) was used for this purpose. It was found that: (i) up to a measuring frequency of about 10 kHz, the complex consisting of needle electrodes and 'tissue' can be regarded as serially connected resistances, R, and capacitances; (ii) the frequency range 3-10 kHz can be regarded as optimal since it simultaneously assures low electrode polarization and a negligible role of tissue capacitance; (iii) increasing the haematocrit had two consequences--a reduced contribution of polarization impedance to the total impedance measured and a decreased sensitivity of ion concentration measurement from R-1 (conductance); (iv) passive electrical properties of renal medullary tissue were close to those of a 75% haematocrit cell suspension; (v) since in high haematocrit suspensions the resistive component of impedance predominates, within the frequency range 3-10 kHz either conductance or admittance, Z-1, can be used as an index of ion concentration; and (vi) impedance changes in kidney tissue are primarily determined by fluctuations of ion concentration with a less important contribution from interstitial volume changes.

Animals↗