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J Orendácová

Publications and source records attributed to J Orendácová.

At least 19 recordsLinked to original sources
PubMed2005

Fluoro-Jade B evidence of induced ischemic tolerance in the rat spinal cord ischemia: physiological, neurological and histopathological consequences.

Fluoro-Jade B, a marker of degenerating neurons, was used to label histopathological changes in the rat spinal cord after transient ischemia and ischemic preconditioning (IPC). To characterize postischemic neurodegenerations and consequent neurological changes, a particular attention was paid to the standardization of ischemic conditions in animals of both groups. 1. The control ischemic rats were submitted to a reversible occlusion of descending aorta by insertion and subsequent inflation of a 2F Fogarty catheter for 12 min. 2. In the IPC rats, an episode of short 3 min occlusion and 30 min reperfusion preceded the 12 min ischemia. Postischemic motor function testing (ambulation and stepping) was provided repeatedly for evaluation of neurological status 2 h and 24 h after surgery and at the end of postischemic survival, i.e. after 48 h. Fluoro-Jade B staining was used to demonstrate degenerated neurons. In the control rats, neurological consequences of histopathological changes in lumbosacral spinal cord, manifested as paraplegia, were present after 12 min ischemia. Thus, numbers of degenerated Fluoro-Jade B positive cells were visible in gray matter of the most injured L(4)-S(2) spinal cord segments. Slight motor function impairment, consequential from significant decreasing in Fluoro-Jade B-positivity in the L(4)-S(2) spinal cord segments of the IPC rats, was considered the pathomorpfological evidence that IPC induces spinal cord tolerance to ischemia. Our results are consistent with the previously published silver impregnation method for histopathological demonstration of ischemic degeneration.

Animals↗
PubMed2001

Cauda equina syndrome.

Single or double-level compression of the lumbosacral nerve roots located in the dural sac results in a polyradicular symptomatology clinically diagnosed as cauda equina syndrome. The cauda equina nerve roots provide the sensory and motor innervation of most of the lower extremities, the pelvic floor and the sphincters. Therefore, in a fully developed cauda equina syndrome, multiple signs of sensory disorders may appear. These disorders include low-back pain, saddle anesthesia, bilateral sciatica, then motor weakness of the lower extremities or chronic paraplegia and, bladder dysfunction. Multiple etiologies can cause the cauda equina syndrome. Among them, non-neoplastic compressive etiologies such as herniated lumbosacral discs and spinal stenosis and spinal neoplasms play a significant role in the development of the cauda equina syndrome. Non-compressive etiologies of the cauda equina syndrome include ischemic insults, inflammatory conditions, spinal arachnoiditis and other infectious etiologies. The use of canine, porcine and rat models mimicking the cauda equina syndrome enabled discovery of the effects of the compression on nerve root neural and vascular anatomy, the impairment of impulse propagation and the changes of the neurotransmitters in the spinal cord after compression of cauda equina. The involvement of intrinsic spinal cord neurons in the compression-induced cauda equina syndrome includes anterograde, retrograde and transneuronal degeneration in the lumbosacral segments. Prominent changes of NADPH diaphorase exhibiting, Fos-like immunoreactive and heat shock protein HSP72 were detected in the lumbosacral segments in a short-and long-lasting compression of the cauda equina in the dog. Developments in the diagnosis and treatment of patients with back pain, sciatica and with a herniated lumbar disc are mentioned, including many treatment options available.

Animals↗
PubMed2001

Fos protein expression in sacral spinal cord in relation to early phase of cauda equina syndrome in dogs.

1. The aim of the present study is to map the incipient phase of Fos expression in the sacral spinal cord neuronal pools of multiple cauda equina constrictions canine model. 2. Fos-positive neurons were found bilaterally in the lateral portion of superficial dorsal horn layers (Laminae I-III) and along the lateral edge of the dorsal horn accompanied by the lateral collateral pathway, fibers of Lissauer's tract, terminating at the sacral parasympathetic nucleus. Similarly, high Fos expression was detected in the ventral portion of the dorsal sacral commissure and in the dorsomedial portion of the anterior horns at S1-S3 segment level. Finally, a clearly expressed Fos-positivity was disclosed bilaterally in the neuropil of the nucleus Y in the anterior horn. 3. Data from the present study show that continuous stimulation of the central fibers of sacral dorsal root ganglia neurons, i.e., fibers of sacral primary afferents, unlike those using various stimulations of the peripheral fibres offers an unusual pattern of Fos-like immunoreactivity.

Animals↗
PubMed2000

Incipient cauda equina syndrome as a model of somatovisceral pain in dogs: spinal cord structures involved as revealed by the expression of c-fos and NADPH diaphorase activity.

Segmental and laminar distribution of Fos-like immunoreactive, reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd)-exhibiting and double-labeled (Fos-like immunoreactive and NADPHd-exhibiting) neurons was examined in lower lumbar and sacral segments of the dog spinal cord using the model of multiple cauda equina constrictions. NADPHd histochemistry was used as marker of nitric oxide synthase-containing neurons. The appearance and the time-course of Fos-like immunoreactive, NADPHd and double-labeled neurons was studied at 2 h and 8 h postconstriction characterized as the incipient phase of cauda equina syndrome. The occurrence of Fos-like immunoreactive and NADPHd-exhibiting neurons in fully developed cauda equina syndrome was studied at five days postconstriction. An increase in Fos-like immunoreactivity in superficial laminae (I-II) and an enhanced NADPHd staining of lamina VIII neurons were found. A statistically significant increase in Fos-like immunoreactive neurons was found in laminae I-II and VIII-X 8 h postconstriction, and in contrast, a prominent decrease in Fos-like immunoreactive neurons was found in laminae I-II, accompanied by a statistically significant increase in Fos-like immunoreactive neurons in more ventrally located laminae VII-X at five days postconstriction. Quantitative analysis of laminar distribution of constriction-induced NADPHd-exhibiting neurons revealed a considerable increase in these neurons in laminae VIII-IX 8 h postconstriction and a statistically highly significant increase in NADPHd-exhibiting neurons in laminae VII-X five days postconstriction. Concurrently, the number of NADPHd-exhibiting neurons in laminae I-II was greatly reduced. While a low number of double-labeled neurons was found throughout the gray matter of lower lumbar and sacral segments at 2 h postconstriction, a statistically significant number of double-labeled neurons was found in lamina X 8 h and in laminae VII-X five days postconstriction. The course and distribution of anterograde degeneration resulting five days after multiple cauda equina constrictions are compared with segmental and laminar distribution of Fos-like immunoreactive and NADPHd-exhibiting neurons. Prominent involvement of the spinal cord neurons appearing in the lumbosacral segments at the early beginning and in fully developed cauda equina syndrome results in a Fos-like immunoreactivity and strongly enhanced NADPHd staining of some neuronal pools. Under such circumstances, an early cauda equina decompression surgery is advisable aimed at decreasing or preventing the derangement of the neural circuits in the lumbosacral segments.

Animals↗
PubMed1998

Reduced nicotinamide adenine dinucleotide phosphate diaphorase in the spinal cord of dogs.

The distribution of somatic, fibre-like and punctate, non-somatic reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase activity was examined in dog spinal cord using horizontal, sagittal and transverse sections. The morphological features of NADPH diaphorase exhibiting neurons divided into six different neuronal types (N1-N6) were described and their laminar distribution specified. Major cell groups were identified in the superficial dorsal horn and around the central canal at all spinal levels, and in the intermediolateral cell column at thoracic level. NADPH diaphorase exhibiting neurons of the pericentral region were distributed in a thin subependymal cell column containing longitudinally-arranged small bipolar neurons with processes penetrating deeply into the intermediolateral cell column and/or running rostrocaudally in the subependymal layer. The second pericentral cell column located more laterally in lamina X contains large, intensely-stained NADPH diaphorase exhibiting neurons with long dendrites radiating in the transverse plane. Neurons of the sacral parasympathetic nucleus seen in segments S1-S3 exhibited prominent NADPH diaphorase activity accompanied by heavily-stained fibres extending from Lissauer's tract through lamina I along the lateral edge of the dorsal horn to lamina V. A massive dorsal gray commissure, with high NADPH diaphorase activity, was found in segments S1-S3. At the same segmental level a prominent group of moderately-stained motoneurons was detected in the dorsolateral portion of the anterior horn. Fibre-like NADPH diaphorase activity was found in the superficial dorsal horn and pericentral region in all segments studied. Punctate, non-somatic NADPH diaphorase activity was detected in the superficial dorsal horn, in the pericentral region all along the rostrocaudal axis and in the nucleus phrenicus (segments C4-C5), nucleus dorsalis (segments Th2-L2), nucleus Y (segments S1-S3), and the dorsal part of the dorsal gray commissure (S1-S3). A schematic diagram documenting the segmental and laminar distribution of NADPH diaphorase activity is given.

Animals↗
PubMed1995

Formation of filamentous and multivesicular bodies after intrathecal MK-801 injection.

Our study of ultrastructural changes in lumbar spinal cord is based on the rats permanent intrathecal (IT) catheter model of MK-801 injection. After 3 days survival with the IT catheter the animals were treated by injection of MK-801 or saline. Five hrs post-treatment the rats were transcardially perfused with 4% paraformaldehyde in 0.1 M PB. L4-5 segments of the spinal cord were dissected and processed for EM. The presence of single or multiple filamentous/multivesicular bodies in neuronal cytoplasm of MK-801 treated animals was apparent.

Animals↗
PubMed1993

A new applicability of the suppressive Nauta method in the early phase of neuronal damage.

A new applicability of the suppressive Nauta impregnation method was tested allowing the detailed mapping of early neuronal damage expressed in the form of somatodendritic argyrophilia. Two spinal cord ischemia-reperfusion models of rabbit and dog, a model of canine global brain ischemia-reperfusion, involving cardiac arrest followed by resuscitation, and a canine spinal cord compression-decompression model were used. Early phases of neuronal damage are characterized by conspicuous somatodendritic argyrophilia permitting an exact evaluation of acute neuronal damage according to soma size, dendritic ramifications and localization of the affected neuronal neuronal pool. By its high sensitivity to somatodendritic damage the suppressive Nauta method appears to be a valuable neuropathological technique.

Animals↗
PubMed1992

Silver impregnability of ischemia-sensitive neocortical neurons after 15 minutes of cardiac arrest in the dog.

The development of postischemic neuronal argyrophilia and the subsequent fate of argyrophilic neurons were studied in dogs after 15 min of complete cerebral ischemia and survival varying from 1 h to 7 days. Histopathological examination of the vulnerable neocortical region was performed using the Nauta degeneration method, and the time course of cellular changes was described. Clear-cut neuronal argyrophilia was found to precede cell body shrinkage and gradual disintegration corresponding to selective neuronal death. To clarify this initial stage of neuronal impregnability, the samples from the animals surviving 8 h postarrest were stained with toluidine blue or processed for electron microscopy, and the distribution of argyrophilic cells was confirmed to be identical with that of hyperchromatic or electron-dense cells. On the other hand, infrequently observed "tissue infarctions" exhibited no silver affinity in spite of apparent cellular damage. These findings indicate that enhanced impregnability is related to cytochemical processes incidental to the phenomenon of "selective neuronal death", which can be readily detected by the Nauta method.

Animals↗
PubMed1992

[Neurotransplantation, critical analysis and perspectives].

Basic morphological and functional properties of basal ganglia are described and their role in the development of Parkinson's disease is discussed in detail. Based on recent experimental data, the problem of human autologous adrenal medulla transplants as well as human dopaminergic neurons is analyzed and prospective approaches to successful therapeutic interventions are considered mainly from the molecular and immunobiological point of view. The relative limitations of the regenerative capacity and transplantability of the nervous tissue are assessed and compared with the critical developmental periods of human neurogenesis (Fig. 6, Ref. 47.).

Adrenal Medulla↗
PubMed1991

The blood-brain barrier permeability in graded postischemic spinal cord reoxygenation in rabbits.

Postischemic blood-brain barrier permeability changes were studied using a rabbit spinal cord ischemia model followed by normoxic recirculation (group I) or graded postischemic reoxygenation (group II). No signs of Evans blue leakage were found in lumbar segments 3 h after normoxic blood recirculation. After 6 h, the fluorescence was apparent in the perivascular space and in the pericytes, followed by a massive penetration of the tracer into the neuropil and perikarya at 12 h survival; 18 h after normoxic reperfusion, the fluorescence was localized in the cytoplasm of the middle-sized and large neurons. Graded postischemic reoxygenation of lumbar segments applied during the same survival periods had a highly protective effect on vascular membrane permeability. The structural components of the vascular wall as well as neuropil and perikarya remained after its application entirely tracer free.

Animals↗
PubMed1988

The relation between free and membrane-bound ribosomes in light dorsal root ganglia neurons after aortic ligature in dogs.

To study the relation between free and membrane-bound ribosomes after repeated aortic ligature we examined light dorsal root ganglia (DRG) neurons by quantitative electron microscopy. For counting ribosomes we applied two methods--the hit method and the total counting of ribosomes on electronograms. By both methods we found that there was a prevalence of free ribosomes in DRG neurons on the first and second postoperative day this relation was significantly shifted in favour of free ribosomes which was in agreement with our morphological findings characterized by disaggregation of polysomes and an increasing number of membrane-free ribosomes. At the advanced period of survival (6 days) the studied relation no longer differed from control values. These findings indicate that reorganized proteosynthesis in light DRG neurons plays a most important role during recovery after ischemic insult.

Animals↗
PubMed1987

The arrangement of endoplasmic reticulum and proteosynthesis in spinal ganglia neurons of dog after ischemia.

The authors studied ultrastructural and biochemical changes in spinal ganglia neurons of dogs after ischemia. Partial spinal cord ischemia was induced by occlusion of the abdominal aorta just below the renal arteries and the arterial blood pressure was registered above and below the occlusion. - In the course of 2-4 hours' ischemia the amount of free ribosomes increased. In some cases the formation of filamentous material or tubular structures inside the cisterns of endoplasmic reticulum was apparent. The proteosynthesis declined. Incorporation of 14C - leucine into the spinal ganglion was 50% as compared to the control animals. The morphological and biochemical changes were more pronounced after 4 h ischemia.

Animals↗
PubMed1984

Ultrastructural and quantitative investigations of the spinal ganglia neurons after ligation of the abdominal aorta.

The structural changes in spinal ganglia neurons of dogs subjected to repeated 40-minute ligation of the abdominal aorta with 1-6 day survival were studied by means of electron microscopy and morphometry. The endoplasmic reticulum shows marked changes with a decrease of bound ribosomes as well as a reduction of the membranous component, especially in the peripheral zone of cytoplasm. There were frequently noticed local deposits of filamentous material. Qualitative and quantitative changes had the same time course, culminating on the second to third day of survival. Later [6 days] some signs of neuronal recovery can be observed.

Animals↗
PubMed1983

Changes in spinal ganglia satellite and Schwann cells after aortic occlusion.

Ultrastructural ischemic changes of satellite and Schwann cells in lumbar spinal ganglia were studied in dog after single 80-minute and repeated 40-minute ligation of the abdominal aorta 3-48 hours survival. Satellite cells undergo greater changes than the Schwann cells. After a single ligation for eighty minutes, the satellite cell cytoplasm reveals lengthened or slightly vacuolated cisterns of the endoplasmic reticulum and more numerous lysosomes. The adneuronal surface of satellite cells shows retraction of the processes. Schwann cells, investing large myelinated axons contain markedly vacuolated endoplasmic reticulum and some osmiophilic inclusions. Three hours after repeated ligation the density of satellite cell cytoplasm is decreased and the cell processes of the adneuronal surface are less numerous. Some satellite cells containing large vacuoles undergo acute degeneration. Three hours after repeated ligation the Schwann cell cytoplasm reveals numerous lamellar bodies. Following 1-2 days survival after repeated ligation, strongly vacuolized satellite cells or those with lower cytoplasmic density are more frequent, but also hypertrophic satellite cells are visible. The changes of the Schwann cells are less advanced and manifest by the vacuolization of the organelles and the presence of lamellar bodies and other osmiophilic inclusions.

Animals↗