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Biomedical subjects

J Polak

Publications and source records attributed to J Polak.

At least 73 records · Page 4Linked to original sources
PubMed1986

Galanin immunoreactivity in hypothalamic neurons: further evidence for multiple chemical messengers in the tuberomammillary nucleus.

By using a specific antibody against the 29 amino-acid peptide galanin (Gal) with light and electron microscopic immunocytochemistry, we have studied the distribution of Gal immunoreactivity in the posterior hypothalamic magnocellular neurons of the rat. In colchicine-treated rats, a large number of Gal-immunoreactive cells were identified within all subdivisions of the tuberomammillary nucleus. The majority of these cells are large multipolar or fusiform neurons, with long, sparsely branching dendrites. A small number project to the ventral hippocampus, as shown by experiments with the retrograde tracing of Fast Blue. Ultrastructural examination of the Gal-immunoreactive cells confirms their indentity as magnocellular neurons, with dense deposits of immunoreaction product, particularly in small ribosomal arrays and in large, dense-cored vesicles. Axosomatic synapses occur on these neurons. The axonal boutons synapse with asymmetric and symmetric junctions and contain small synaptic vesicles as well as numerous large, dense-cored vesicles, which display Gal immunoreactivity. Sequential staining of thin, alternate sections with antibodies against Gal and L-histidine decarboxylase (HDCase; EC 4.1.1.22) showed colocalization of Galand HDCase-immunoreactivities in a majority of tuberomammilary neurons. The finding of Gal immunoreactivity within histamine-producing neurons of the tuberomammillary nucleus adds to the multiplicity of potential neuronal messengers utilized by these cells.

Animals↗
PubMed1985

[X-ray semiotics of the morphological and functional changes in chronic bronchitis].

The authors analysed structural disorders of a pulmonary pattern in patients with non-obstructive, obstructive and purulent bronchitis. Characteristic x-ray symptom-complexes were singled out for each clinical variant of the disease. In addition to roentgenomorphological changes functional disorders showing changes of biomechanics in patients with chronic bronchitis were revealed at roentgenopneumopolygraphy.

Adult↗
PubMed1984

Innervation of human bone periosteum by peptidergic nerves.

Nerves exhibiting substance P-like immunoreactivity were demonstrated in the human periosteum. A network of nerves showing substance P-like immunoreactivity was seen in the periosteum, while finer strands of immunoreactive nerve fibers were present immediately beneath the surface of the periosteum. Enkephalin-like immunoreactivity was also studied but could not be demonstrated. Substance P has previously been suggested to be involved in the mediation of the sensation of pain. The clinically observable marked pain sensitivity of periosteal tissue might be explained by the peptidergic nerves described in this paper.

Fluorescence↗
PubMed1984

Changes in substance P- and neuropeptide Y-immunoreactive fibres in rat and guinea-pig irides following unilateral sympathectomy.

Substance P (SP)-immunoreactive fibres have been found in the rat and guinea-pig irides. They are distributed parallel to the pupillary margin in the sphincter muscle, and in an irregular plexus in the dilator muscle of both species. Neuropeptide Y (NPY)-immunoreactive fibres have also been demonstrated in the anterior uvea, displaying a pattern similar to that of the adrenergic nerves. One month after sympathectomy, there was an increase both in the density and possibly in the number of SP-immunoreactive fibres in the denervated irides of both rodent species. In the sympathectomized iris, there was a very notable decrease in the density of NPY-immunoreactive fibres indicating that the NPY peptide most likely coexists with the classical sympathetic neurotransmitter, noradrenaline, in the sympathetic nerve supply derived from the superior cervical ganglion. The disappearance of dopamine beta-hydroxylase (DBH) immunostaining fibres confirmed the success of the sympathetic denervation.

Animals↗
PubMed1982

Computed tomographic studies of the head in a teaching hospital and a community hospital: a comparison.

This investigation compared the use of computed tomography (CT) of the head at a large primary medical-school-affiliated hospital and at a large community hospital. There were two aims: first, to study the intrinsic characteristics of the patients in an attempt to determine the potential for developing accurate discrimination algorithms; and second, to study the patterns of neurodiagnostic tests used at these facilities. The results indicated that separability of patients into normal and abnormal categories at both institutions was extremely small. In addition, there was no significant difference in the numbers of types of ancillary tests used at both institutions. Overall, these data once more confirm the difficulty of altering CT usage patterns in primary or secondary hospitals without significantly affecting the number of abnormal patients identified.

Boston↗
PubMed1980

[Transthoracic needle-biopsy in coin-lesions of the lung-comparison of the results of different procedures (author's transl)].

This report deals with the results and the complications of transthoracic needle-biopsy performed with different methods at two cooperating hospitals (Prague and Bad Berka). Each hospital investigated 200 persons. As for tumours thin-needle biopsy yielded more positive results for tumours also more false positive results. As for other localized lung diseases the biopsy by means of a Hauser-needle was more successful.

Adolescent↗
PubMed1978

G cell population of the gastric antrum, plasma gastrin, and gastric acid secretion in patients with and without duodenal ulcer.

Estimates of the G cell population were made in 24 resected human pyloric antra from counts of cells in multiple samples and from measurements of antral size. Measurements had been made previously in 20 subjects of acid output (basal and after pentagastrin) and in 10 subjects of plasma gastrin (basal and after insulin + bicarbonate). G cells were most dense near the pylorus, but their circumferential distribution was even. The G cell populations ranged from 8 to 15 (mean 10) million in four control patients and from 3 to 43 (mean 18) million in 15 patients with duodenal ulcer. Those with recurrent ulcer after vagotomy had either a low G cell count and incomplete vagotomy, or a high G cell count and apparently complete denervation. Two patients with hypergastrinaemia and duodenal ulcer had moderate (29 X 10(6)) or marked (56 X 10(6)) excesses of G cells. 'G cell hyperplasia' may represent the extreme end of the normal range of G cell numbers in the antrum, and can be assessed by semi-quantitative grading of G cell hyperplasia in antral biopsies. There were significant direct correlations between antral area and G cell density, between peak acid output and G cell population, and between basal plasma gastrin and G cell density (but not population). We suggest that, in patients with duodenal ulcer, acid and gastrin secretion are interrelated and that both are related to the masses of parietal cells and of G cells.

Cell Count↗