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J Dabrowska

Publications and source records attributed to J Dabrowska.

At least 19 recordsLinked to original sources
PubMed2006

Degeneration of dopaminergic mesocortical neurons and activation of compensatory processes induced by a long-term paraquat administration in rats: implications for Parkinson's disease.

A deficiency of the dopaminergic transmission in the mesocortical system has been suggested to contribute to cognitive disturbances in Parkinson's disease. Therefore, the aim of the present study was to examine whether the long-term administration of a commonly used herbicide, paraquat, which has already been found to induce a slowly progressing degeneration of the nigrostriatal neurons, influences mesocortical dopaminergic neurons in rats. Paraquat at a dose of 10 mg/kg i.p. was injected either acutely or once a week for 4, 8, 12 and 24 weeks. Acute treatment with this pesticide increased the level of homovanillic acid (HVA) and HVA/dopamine ratio in the prefrontal cortex. After 8 weeks of administration paraquat increased the number of stereologically counted tyrosine hydroxylase-immunoreactive (TH-ir) neurons and their staining intensity in the ventral tegmental area (VTA), which is a source of the mesocortical dopaminergic projection. At the same time, few TH-ir neurons appeared in different regions of the cerebral cortex: in the frontal, cingulate, retrosplenial and parietal cortices. Chronic paraquat administration did not influence the level of dopamine in the prefrontal cortex but increased the levels of its metabolites: 3,4-dihydroxyphenylacetic acid (after 8-12 weeks), HVA (after 4 and 12 weeks) and HVA/dopamine ratio (4 weeks). After 24 weeks this pesticide reduced the number of TH-ir neurons in the VTA by 42% and of the Nissl-stained neurons by 26%, and induced shrinkage of this structure by ca. 25%. Moreover, TH-ir neurons in the cortex were no more visible after such a long period of administration and levels of dopamine metabolites returned to control values. The present results suggest that the long-term paraquat administration destroys dopaminergic neurons of the VTA. However, compensatory activation of the VTA neurons and cortex overcomes progressing degeneration and maintains cortical dopaminergic transmission.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2005

Variation of the thermal neutron diffusion cooling properties of wet rock material (Monte Carlo simulations of the pulsed neutron experiments).

The water content in a rock material can significantly change the thermal neutron diffusion parameters with respect to those of the dry medium. The effect has been studied for dolomite, CaMg(CO3)2, by Monte Carlo simulations of the variable buckling experiments for 10 series of samples. The density-removed diffusion cooling coefficient C(M) varies hyperbolically by two orders of magnitude with water content in the range of 0-20%.

Journal Article↗
PubMed2005

A slowly developing dysfunction of dopaminergic nigrostriatal neurons induced by long-term paraquat administration in rats: an animal model of preclinical stages of Parkinson's disease?

The aim of the present study was to examine the influence of the long-term paraquat administration on the dopaminergic nigrostriatal system in rats. Paraquat was injected at a dose of 10 mg/kg i.p. for 4-24 weeks. We found that this pesticide reduced the number of tyrosine hydroxylase-immunoreactive neurons of the substantia nigra; after the 4-week treatment the reduction (17%, nonsignificant) was confined to the rostrocentral region of this structure but, after 24 weeks, had spread along its whole length and was approximately 37%. Moreover, it induced a biphasic effect on dopaminergic transmission. First, levels of dopamine, its metabolites and turnover were elevated (4-8 weeks) in the caudate-putamen, then all these parameters returned to control values (12 weeks) and dropped by 25-30% after 24 weeks. The binding of [3H]GBR 12,935 to dopamine transporter in the caudate-putamen was decreased after 4-8 weeks, then returned to control values after 12 weeks but was again decreased after 24 weeks. Twenty-four-week paraquat administration also decreased the level of tyrosine hydroxylase (Western blot) in the caudate-putamen. In addition, paraquat activated serotonin and noradrenaline transmission during the first 12 weeks of treatment but no decreases in levels of these neurotransmitters were observed after 24 weeks. The above results seem to suggest that long-term paraquat administration produces a slowly progressing degeneration of nigrostriatal neurons, leading to delayed deficits in dopaminergic transmission, which may resemble early, presymptomatic, stages of Parkinson's disease.

Algorithms↗
PubMed2003

Diffusion cooling of thermal neutrons in basic rock minerals by Monte Carlo simulation of the pulsed neutron experiments.

The pulsed neutron experiment (the variable geometric buckling experiment) in spherical geometry has been simulated using the MCNP code. The time decay of the thermal neutron flux has been observed as a function of the sample size. The thermal neutron diffusion cooling coefficient C with the correction F has been determined for three basic rock minerals (quartz, calcite, dolomite) at the given specific densities. The corresponding density-removed parameters have also been obtained.

Journal Article↗
PubMed2000

alpha1-microglobulin as a marker of proximal tubular damage in urinary tract infection in children.

The urinary alpha1-microglobulin (alpha1-M) as a marker of proximal tubular damage was measured in 86 children, aged 3/12 to 12 years, with a diagnosis of urinary tract infection (UTI) and fever. All patients had normal glomerular filtration rates (GFR). They were divided into 2 groups: A: with UTI and etiological factor E. coli, B: with UTI and etiological factor Proteus sp. Similar measurements of alpha1-M were obtained for a control group of healthy children. An increased mean level serum alpha1-M was observed in patients with UTI and fever compared to control group (p < 0.001). Urinary alpha1-M as the alpha1-microglobulin/creatinine ratio was higher in both tested group of patients with UTI and fever. Those found in group A1 and B1 before treatment were the highest and statistically significantly elevated after treatment (group A2 and B2: p < 0.001). Our results indicate the usefulness of the urinary alpha-microglobulin/creatinine ratio as a marker of proximal kidney tubule damage in children with E. coli and Proteus sp. infections. Additionally, it seems to be associated with the humoral and cellular immune response.

Alpha-Globulins↗
PubMed1997

[Morphologic parameters of blood platelets and dysmorphic erythrocyturia in chronic glomerulonephritis].

Dysmorphic erythrocyturia is known as an attribute of glomerular bleeding. During chronic glomerulonephritis the morphological changes of blood platelets were also observed. The subject of our study was to indicate if the common mechanism leading to blood platelets polymorphology and dysmorphic erythrocytes origination in chronic glomerulonephritis is possible. We estimate the count of blood platelets (PLT), mean platelets volume (MPV), platelet distribution weight (PDW) and platelets crit (PCT) in peripheral blood of 46 patients with chronic glomerulonephritis with dysmorphic erythrocyturia (26 with renal sufficiency and 20 with renal insufficiency) and 32 healthy volunteers. The dysmorphic erythrocyturic erythrocytes were examined in first morning urine. We have not demonstrated the correlation of changes in blood platelets morphology with percent dysmorphic erythrocytes in urine. The results of our investigations do not confirm exactly the common mechanism of the morphological changes which were observed. Minimal changes of the blood platelets parameters may be the results of changes in structure of phospholipids platelets membrane as well as less activation of platelets membrane receptors-GP Ia/IIb and GP Ic/IIa.

Adult↗
PubMed1990

[Neurologic manifestations of chronic alcoholism].

The authors have analyzed histories of 146 alcoholics admitted to the Clinic of Neurology. Results of this analysis and review of the literature became background for presentation of contemporary views on the clinic and neuropathology of chronic alcoholism.

Adult↗
PubMed1983

Enhanced preference for perceptual novelty in the monkey after section of the fornix but not after ablation of the hippocampus.

Previously uncovered discrepancies between the behavioral effects of fornix sections and hippocampal ablations in the monkey suggested that damage to the fornix but not that to the hippocampus may result in a motivational post-operative change. To test this notion, control monkeys and those with damage to either hippocampus or fornix were given an opportunity to choose freely between presentations of novel or repetitive stimuli in two modalities. In the visual mode, the choice was between viewing color slides which changed on every trial or repeated presentations of a geometric pattern (experiments 1 and 1a). In the auditory mode, the choice was between trains of identical clicks and different sound patterns (experiments 2 and 2a). Monkeys with sections of the fornix, but not those with ablations of hippocampus, showed an abnormally marked preference for novel stimuli in both modalities, even when perceptual novelty was designed to compete unfavorably with food reward (experiments 1b and 2b). These findings (a) provide another instance of functional dissociation between the effects of fornix and hippocampal damage and caution against assuming safely that data obtained with sections of the fornix will always mirror the behavioral consequences of hippocampal ablations; and (b) suggest that the hippocampus of primates may participate in the mediation of cognitive-motivational aspects of behavior which should be taken into account when the role of the hippocampus in memory processes is considered.

Animals↗
PubMed1980

Subcortical connections of the prefrontal cortex in dogs: afferents to the orbital gyrus.

Afferent subcortical connections to the lateral prefrontal cortex (orbital gyrus) in the dog brain were investigated using the horseradish peroxidase retrograde transport method. It was shown that: (i) the main projection to this area derives from the ventral and intermediate regions of the mediodorsal nucleus of the thalamus, (ii) fairly rich projection arises from the midline, intralaminar as well as from ventromedial and lateroposterior thalamic nuclei, (iii) scanty extrathalamic projection to the lateral prefrontal area originates from several other structures like claustrum, hypothalamus, amygdala, ventral tegmental area, raphe nuclei and locus coeruleus. Distribution of labeled cells after particular injections showed that in the orbital gyrus two subdivisions may be distinguished: dorsal and ventral. It is suggested that the dorsal orbital subdivision in dog corresponds to the lateral prefrontal cortex in monkey.

Animals↗
PubMed1980

Septal lesions and reversal learning in dogs.

The course of asymmetrical or symmetrical go, no-go differentiation reversal was compared in 16 control and 16 septally lesioned dogs using two pairs of auditory stimuli (similar or dissimilar). The magnitude of impairment observed during the course of reversal in septal dogs was affected by the quality of discriminated stimuli, asymmetrical or symmetrical differentiation procedure and the extent of lesion. The results suggest that septal and normal dogs solving the reversal problem used different strategies for transformation of conditioned properties of the stimuli.

Animals↗
PubMed1978

Deficit in postoperative learning and retention of complex tasks by septal rats.

Pre- and postoperative acquisition and retention of locomotor tasks of different complexity were investigated in septal rats. Experiment I involved acquisition and retention of a task using a four-unit-quadruple-choice apparatus. Severe impairment in both postoperative acquisition and postoperative retention was observed from all parameters of learning: trials, errors, repetitive errors and vicarious responses. However, there were significant savings in postoperative retention, scores compared to postoperative acquisition by septal rats. Experiment II examined acquisition and retention of a less complex task by using a two-unit-quadruple-choice apparatus. Impairment of postoperative acquisition in septal rats was reflected only in the number of trials to learning criterion and vicarious responses, while the number of errors and repetitive errors were not distinguished between normal and septal animals. Retention deficits in the septal rats were reflected in all learning parameters, although there were savings in postoperative retention compared to postoperative acquisition scores attained by septal rats. It is suggested that lesions of the septal area in rats may change the integration of intero- and exteroceptive cues, providing a source of interference if the task can be solved by the use of more than one strategy.

Animals↗