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Biomedical subjects

C Kowalski

Publications and source records attributed to C Kowalski.

At least 19 recordsLinked to original sources
PubMed2002

Bacterial resistance to quinolone antibiotics in Poland.

The resistance of 167 pathogenic bacteria of animal origin to quinolones was determined by the disc diffusion method, and by the minimum inhibitory concentration (MIC) test. The highest resistance of Escherichia coli was found to be against nalidixic acid (NA), 49.1% and flumequine (FLU), 38.2%. The sensitivity of the strains were: ciprofloxacin (CIP; 81.8%); enrofloxacin (ENR; 81.8%); norfloxacin (NOR; 80.0%); and pefloxacin (PE; 76.4%). Salmonella spp. showed 100% sensitivity to CIP, ENR, NOR and PE. A high resistance percentage in the cases of: FLU (86.7%); PE (50.0%); and CIP (26.65%) distinguished the Streptococcus spp. The highest percentage sensitivity of Staphylococci was found with three fluoroquinolones: CIP, ENR and NOR, 94.3% each (66 strains). The studies did not indicate that a total cross-resistance might occur between the examined quinolones.

Animals↗
PubMed2002

Pharmacokinetics of tylosin in broiler chickens.

Biological availability and pharmacokinetic properties of tylosin were determined in broiler chickens after oral (p.o.) and intravenous (i.v.) administration at a dose of 10 mg/kg. The calculated bioavailability--F%, by comparing AUC values--p.o. and AUC--i.v., ranged from 30%-34%. After intravenous injection tylosin was rapidly distributed in the organism, showing elimination half-life (t1/2 beta) values of 0.52 h and distribution volume (Vd) of 0.69 L/kg, at a clearance rate (Cl) of 5.30 +/- 0.59 ml/min/kg. After oral administration, tylosin has a similar distribution volume (Vd = 0.85 L/kg), while the elimination half-life t1/2 beta of 2.07 h was four times bigger than after i.v. administration at Cl = 4.40 +/- 0.27 ml/min/kg. The obtained value tmax = 1.5 h for tylosin after oral administration indicates that using this antibiotic with drinking water in broiler chickens is the method of choice. However, a relatively low value Cmax = 1.2 micrograms/ml after oral administration of tylosin shows that dosing of this antibiotic in broiler chickens should be higher than in other food producing animals.

Administration, Oral↗
PubMed1997

The function of neutrophils isolated by a magnetic antibody cell separation technique is not altered in comparison to a density gradient centrifugation method.

Most comparative studies on neutrophil (PMN) isolation techniques have shown either activation or functional impairment of the cells due to the different separation processes. We have established a preparation method for PMN from human whole blood employing iron tagged, magnetizable antibodies against the cell surface antigen CD15. The aim of our study was to test whether this magnetic separation (MACS) alters cellular functions of PMN in comparison to a conventional density gradient technique (Percoll). The purity, cell yield, and pre-activation of the cells were evaluated. The latter was assessed by quantifying the expression of the integrin CD11b using flow cytometry. Furthermore, as functional tests, cell morphology and the oxidative burst reaction were investigated. We have shown that the use of 'magnetic' antibodies leads to highly purified PMN (> 99% of isolated leukocytes), while there is still contamination by eosinophils (about 6%) after Percoll separation. Platelet contamination was about the same in both procedures (approx. one platelet per two PMN). The basal expression of CD11b and, hence, neutrophil activation, was significantly lower and the upregulation of CD11b in response to FMLP was more pronounced after magnetic separation, as compared to density gradient centrifugation. The MACS technique did not lead to polarisation of PMN, nor did it affect the oxidative burst. This study suggests that magnetic separation is a simple, time-saving technique, yielding highly purified and functionally intact PMN.

Centrifugation, Density Gradient↗
PubMed1997

Retention of leucocytes in reperfused, isolated hearts does not cause haemodynamically relevant permanent capillary plugging.

Effects of microspheres (5 microns or 10 microns diameter) and polymorphonuclear leucocytes (PMN) on coronary resistance were compared in beating, non-working isolated guinea-pig hearts (Langendorff preparation). The hearts were buffer perfused (5 ml/min, constant flow) and particles or cells were infused into the coronary system as a bolus (1 ml, 1 min). Coronary perfusion pressure, coronary flow and formation of epicardial transudate were measured before and after bolus administration. Coronary resistance was estimated from these parameters. Retention of particles or cells was monitored by quantifying the numbers emerging in the coronary effluent in relation to the number administered. The effects of PMN were also studied after 15 min of global ischemia. Coronary resistance correlated with the number of 10-micron particles infused, which were almost quantitatively retained. In contrast, 5-micron beads had no such effect and were not retained in the coronary system. Though considerable numbers of PMN were retained in the hearts (about 21% under control conditions and 35% after ischaemia), coronary resistance was not increased in either case. Blockage of the CD18 adhesion complex by monoclonal antibodies lowered basal retention to 11% and completely prevented the elevation of retention by ischaemia. We conclude that, in this experimental model, PMN, permanently retained in the hearts under normal flow conditions and especially after brief ischaemia, do not cause acute, haemodynamically relevant capillary plugging, but adhere to postcapillary venules via CD18.

Animals↗
PubMed1997

Halothane, isoflurane, and sevoflurane reduce postischemic adhesion of neutrophils in the coronary system.

BACKGROUND: Polymorphonuclear neutrophils (PMNs) contribute to postischemic reperfusion damage in many organs and tissues, a prerequisite being adhesion of PMNs to vascular endothelial cells. Because adhesion processes involve orderly interactions of membrane proteins, it appeared possible that "membrane effects" of volatile anesthetics could interfere. We investigated the effects of halothane, isoflurane, and sevoflurane on postischemic adhesion of human PMNs in the intact coronary system of isolated perfused guinea pig hearts. METHODS: The hearts (n = 7-10 per group) were perfused in the "Langendorff" mode under conditions of constant flow (5 ml/min) using modified Krebs-Henseleit buffer equilibrated with 94.4% oxygen and 5.6% carbon dioxide. Global myocardial ischemia was induced by interrupting perfusion for 15 min. In the second minute of reperfusion (5 ml/min), a bolus dose of 6 x 10(5) PMNs was injected into the coronary system. The number of cells reemerging in the coronary effluent was expressed as a percentage of the total number of applied PMNs. Halothane, isoflurane, and sevoflurane, each at 1 and 2 minimal alveolar concentration (MAC), were vaporized in the gas mixture and applied from 14 min before ischemia until the end of the experiment. RESULTS: Under nonischemic conditions, 24.7 +/- 1.3% of the injected neutrophils did not reemerge from the perfused coronary system. Subjecting the hearts to global ischemia augmented retention (36.4 +/- 2.8%, P < .05). Application of halothane reduced adhesion of neutrophils to 22.6 +/- 2.1% and 24.2 +/- 1.8% at 1 and 2 MAC, respectively (P < .05). Exposure to 1 and 2 MAC isoflurane was similarly effective, whereas basal adhesion was not significantly influenced. Sevoflurane-treated hearts (1 and 2 MAC) also showed decreased adhesion of PMNs (23 +/- 2.3% and 24.8 +/- 1.8%, respectively; P < .05) and an identical reduction resulted when sevoflurane (1 MAC) was applied only with the onset of reperfusion. CONCLUSIONS: Although the mechanism of action of volatile anesthetics remains unclear in these preliminary studies, their inhibitory effect on ischemia-induced adhesion of PMNs may be beneficial for the heart during general anesthesia.

Anesthetics, Inhalation↗
PubMed1996

Workroles of staff nurses in psychiatric settings.

The purpose of this research was to operationalize Peplau's workroles of the psychiatric staff nurse. Thirty registered nurses audiotaped one-to-one interactions with 62 adult, child, and adolescent psychiatric patients. Content analysis was used to identify role behaviors and to identify roles that were different from those outlined by Peplau. The counselor role was the most frequently occurring primary workrole. Overlap was found between behaviors indicative of autocratic leader versus surrogate and those of resource person versus teacher. The findings supported Peplau's contention that the counselor role is central to the practice of psychiatric nursing.

Adult↗
PubMed1995

Emergence of a synaptic neuronal network within primary striatal cultures seeded in serum-free medium.

In order to investigate the basic cellular mechanisms involved in neuronal interactions within the striatum, we prepared a primary striatal cell culture from rat fetal brain in chemically defined medium. Using morphological and whole-cell recording methods, we observed that an intensive neuritic elongation with a progressive build up of a sodium-dependent electrogenesis occurred during the first week of culture. Morphologically mature synapses began to develop after 10 days in vitro. By this time, most of the neurons (82 +/- 9%) received spontaneously synaptic potentials, which led them to fire (71 +/- 11%). The spontaneous firing was prevented by cadmium (200 microM) and tetrodotoxin (5 microM), which suggested that a Ca(2+)-dependent release of neurotransmitters was involved in the synaptic activation. We further obtained evidence that GABA, and to a lesser extent acetylcholine, contributed to these spontaneous synaptic potentials. At 15 days in vitro, it was possible to observe up to four synaptic contacts on a given dendrite. By this time, whole-cell recordings performed on pairs of neurons showed that the mature neurons were interconnected by excitatory synapses. As the number of synapses increased, the striatal neurons gradually formed a large network in which spontaneous activity developed, which tended to be organized into synchronized bursting patterns.

Action Potentials↗
PubMed1995

Zonal differences in adrenocortical lipid peroxidation: role of alpha-tocopherol.

Studies were done to evaluate the relationship between alpha-tocopherol (alpha-T) concentrations and lipid peroxidation (LP) in vitro in microsomal preparations from the inner (zona reticularis) and outer (zona fasciculata plus zona glomerulosa) zones of the guinea pig adrenal cortex. Microsomes were incubated with ferrous ion (Fe2+) to promote free radical production, and alpha-T levels and LP were monitored after various incubation times. alpha-T concentrations were far lower in inner than outer zone preparations and were rapidly depleted from inner zone microsomes by incubation with Fe2+. Coinciding with alpha-T depletion was a large and rapid increase in LP. With outer zone microsomes, alpha-T depletion required more than 30 min, and very little LP was demonstrable during this period. However, once alpha-T depletion occurred, LP was rapidly initiated and reached levels similar to those obtained with inner zone preparations. Inhibition of LP by MnCl2 prevented the Fe(2+)-induced declines in alpha-T in both zones. The results demonstrate the importance of alpha-T as a modulator of adrenal LP and indicate that the zonal differences in LP are largely attributable to the differences in alpha-T concentrations.

Adrenal Cortex↗
PubMed1993

Dopamine decreases striatal enkephalin turnover and proenkephalin messenger RNA abundance via D2 receptor activation in primary striatal cell cultures.

Dopaminergic regulation of striatal enkephalin biosynthesis and secretion was studied in primary neuronal cultures from fetal rat striatum. To allow pharmacological treatment, striatal primary cell cultures were seeded in chemically defined medium onto extracellular matrix. In these conditions, pharmacological treatment of the striatal neurons on the 10th day in vitro for 48 h with 10(-6) M dopamine induced a 50% decrease in preproenkephalin mRNA level concomitant with a 50% decrease in methionine enkephalin neuronal content. These effects of dopamine were mimicked by the D2 agonist bromocriptine (10(-6) M). The decrease in methionine enkephalin neuronal content induced by dopamine or bromocriptine was reversed by the simultaneous application of sulpiride (10(-6) M), a selective D2 antagonist. Interestingly, the D1 agonist SKF 38393 (10(-6) M) application for 24 or 48 h was found to have no significant effect on methionine enkephalin neuronal content. To ensure dopamine regulation of enkephalin secretion, shorter dopaminergic treatments were performed. Dopamine application (10(-6) M) for 2 h had no significant effect on basal methionine enkephalin secretion but significantly decreased (50%) methionine enkephalin secretion induced by KCl 56 mM. This effect of dopamine on the KCl-induced methionine enkephalin secretion was mimicked by bromocriptine (10(-6) M), reversed by sulpiride (10(-6) M) and unaffected by the D1 antagonist SCH 23390 (10(-6) M) application onto striatal neurons. Our data provide direct evidence for a dopaminergic inhibitory control on enkephalin biosynthesis and secretion from striatal cell cultures, mediated through the dopaminergic D2 receptor activation.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Age-related changes in cortico-releasing factor, somatostatin, neuropeptide Y, methionine enkephalin and beta-endorphin in specific rat brain areas.

We investigated the age-related changes in the tissular protein, cortico-releasing factor (CRF), somatostatin (SOM), neuropeptide Y(NPY), methionine enkephalin (M-ENK) and beta-endorphin (beta-END) levels in frontal cortex, hippocampus, striatum and hypothalamus of young (4-month-old), mature (18-month-old) and senescent (26-month-old) Wistar male rats, bred in a specific pathogen free environment. Between the age of 4 and 18 months, the tissular protein levels increased in all 4 structures studied. The CRF and SOM levels increased in the hippocampus, while the NPY levels decreased. During this time, the NPY content increased in the striatum, whereas the SOM and M-Enk striatal levels decreased. Concomitantly, the NPY and beta-End levels decreased in the hypothalamus. Interestingly, no significant variations were found to occur in the frontal cortex whatever the neuropeptide studied. Between the age of 18 and 26 months, no significant changes in the tissular protein levels were detected, except in the hippocampus. The changes in the neuropeptide concentrations observed during this period depended on the neuropeptide and the brain structure studied. The CRF and beta-End levels decreased in the frontal cortex and the hypothalamus, respectively. The NPY peptidergic systems seem to be preferentially affected by aging processes since 3 out of the 4 structures studied--the frontal cortex, the striatum and the hypothalamus--showed a decrease in their tissular NPY content. During the same period, none of the 5 neuropeptides studied were affected in the hippocampus.

Aging↗
PubMed1991

Striatal proenkephalin turnover and gene transcription are regulated by cyclic AMP and protein kinase C-related pathways.

Preproenkephalin metabolism, in the rat, was studied in primary striatal neurons maintained in a chemically defined medium. Acute treatment (30 min) with forskolin (10(-5) M) or phorbol 12 myristate 13 acetate (10(-7) M) resulted, respectively, in a two- and seven-fold increase in methionine-enkephalin secretion. Chronic treatment with forskolin or phorbol 12 myristate 13 acetate (24 h) induced a 100% increase in methionine-enkephalin content (forskolin) and on the other hand a 50% decrease in methionine-enkephalin (phorbol 12 myristate 13 acetate). Both treatments increased preproenkephalin mRNA levels in a time-dependent manner, this augmentation being observable after 180 min by Northern blot analysis and in situ hybridization. These data indicate that under chronic stimulation, with either forskolin or phorbol 12 myristate 13 acetate, proenkephalin turnover is accelerated. However, after stimulation with phorbol 12 myristate 13 acetate, the more potent methionine-enkephalin secretagogue, increased peptide synthesis is not sufficient to replenish methionine-enkephalin intracellular stores. Preproenkephalin gene transcription was analysed by introducing the preproenkephalin gene promoter fused to the bacterial acetyl chloramphenicol transferase reporter gene into primary neurons. Chronic stimulation (48 h) by forskolin (10(-5) M) or phorbol 12 myristate 13 acetate (10(-7) M) of striatal neurons transfected with this fusion gene increased chloramphenicol acetyltransferase activity six-fold and the two effects were additive. These data suggest that the cyclic AMP and the protein kinase C pathways directly activate preproenkephalin gene transcription.

Animals↗
PubMed1989

Ontogenetic expression of peptidyl-glycine alpha-amidating monooxygenase mRNA in the rat pancreas.

Qualitative and quantitative expression of m.RNA coding for Peptidyl-Glycine alpha-Amidating Monooxygenase (PAM) in the developing rat pancreas was investigated by Northern and dot blot hybridization, with a bovine PAM c.DNA probe (0.7 kb fragment). A specific hybridization signal was evidenced for a 3.7 kb m.RNA species. Measurement of PAM m. RNA rate during the rat pancreas ontogenesis revealed a biphasic profile which appeared corelated with that of gastrin and TRH m.RNA respectively. On the other hand, streptozotocin-treatment resulted in a 50% decrease of PAM m.RNA levels.

Aging↗
PubMed1988

Parent attitudes and child personality traits in hemophilia: a six-year longitudinal study.

Using standardized instruments, personality traits of twenty-two hemophilic boys and child-rearing attitudes and practices of their parents were evaluated at the beginning and end of a six-year period, during which psychosocial services were provided in a comprehensive care hemophilia program. The children changed significantly in a positive direction on two traits, enthusiasm and self-reliance. No significant negative personality trait changes were found. Scores remained within the normal range on the remaining traits, with the exception of a significant positive elevation on the intelligence dimension at both pre- and posttest. Mothers and fathers scored positively compared with parental attitude norms during both the initial and follow-up evaluations, without significant changes in overall mean scores. Strong relationships were revealed between individual changes in child personality and parent attitude scores. Despite the fact that between pre- and posttest boys with hemophilia and their parents became aware of the risk of contracting AIDS from blood product use, personality traits and parent child-rearing attitudes remained positive.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Ontogenesis of TRH mRNA in the rat pancreas.

The rapid changes in TRH levels in the rat pancreas during the neonatal period make this organ an interesting model for the study of the regulation of TRH biosynthesis. Pancreatic RNAs were isolated by the guanidinium thiocyanate method and layered onto CsCl cushion. Northern blot preparations were hybridized with 32P labeled TRH cDNA probe. Pancreatic TRH mRNA was first detected in 19-day old fetuses and reached the highest level on day 0, then decreased, being barely detectable 14 days after birth. The neonatal injection of streptozotocin induced a dramatic drop of TRH mRNA levels 24 hours later. This result suggests that the peculiar evolution of TRH level in pancreas is partly due to the evolution of the expression of the TRH gene.

Animals↗
PubMed1986

Detection of the mRNA coding for enkephalin precursor in the rat brain and adrenal by using an 'in situ' hybridization procedure.

The messenger RNA coding for preproenkephalin A (PPA) has been detected in tissue sections of the rat brain and adrenal by using two rat PPA cDNAs labeled with 32P or 35S as probes. In the brain, neurons were labeled in areas known to correspond to sites of synthesis of enkephalins, including the caudate-putamen, the nucleus accumbens, the olfactory cortex, the hypothalamus, the brainstem and the granular layer of the cerebellum. The presence of the PPA mRNA in the normal rat adrenal medulla shows transcription of the PPA gene in such cells despite the absence of enkephalin immunoreactivity in them. These results demonstrate in situ hybridization as an efficient technique to detect the site of synthesis of PPA.

Adrenal Medulla↗