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Biomedical subjects

E Jankowska

Publications and source records attributed to E Jankowska.

At least 37 records · Page 2Linked to original sources
PubMed2001

Structural studies of cysteine proteases and their inhibitors.

Cysteine proteases (CPs) are responsible for many biochemical processes occurring in living organisms and they have been implicated in the development and progression of several diseases that involve abnormal protein turnover. The activity of CPs is regulated among others by their specific inhibitors: cystatins. The main aim of this review is to discuss the structure-activity relationships of cysteine proteases and cystatins, as well as of some synthetic inhibitors of cysteine proteases structurally based on the binding fragments of cystatins.

Amino Acid Motifs↗
PubMed2001

In vitro culture of human epithelial cells on a modified xenogenic collagen support.

Human epithelial cells (HeLa, HaCaT, NHK) were cultured in vitro on chemically modified collagen membranes. Adhesion to the support was measured by estimation of the percentage of adhering 51Cr-labeled cells. Proliferation was estimated with the XTT test. Morphological observations of cells growing on HCl-treated collagen were performed using histological and electron microscopic techniques. HCl and trypsin-modified xenogenic collagen was found to be a good support for human cells in vitro. EDTA-incubated collagen enhanced neither adhesion nor proliferation. The best adhesion and proliferation were found on HCl-treated collagen, depending, however, on the kind of cells.

Cell Adhesion↗
PubMed2000

Coupling between serotoninergic and noradrenergic neurones and gamma-motoneurones in the cat.

Noradrenaline is known to suppress transmission from group II muscle afferents when locally applied to gamma-motoneurones, and serotonin (5-HT) facilitates the transmission. The purpose of this investigation was to search for evidence of monoaminergic innervation of gamma-motoneurones. Eight gamma-motoneurones were labelled with rhodamine-dextran, and 50 micrometer thick sagittal sections of the spinal cord containing them were exposed to antibodies against dopamine beta-hydroxylase (DBH) and 5-HT. All the cells were directly and/or indirectly excited by muscle group II afferents from the muscle they innervated and/or other muscles. Appositions between monoaminergic fibres and the labelled somata and dendrites were located with three-colour confocal laser scanning microscopy by examining series of optical sections at 1 or 0.5 micrometer intervals. DBH and 5-HT varicosities formed appositions with the somata and dendrites of all the gamma-motoneurones. The mean packing densities for 5-HT (1.12 +/- 0.11 appositions per 100 micrometer(2) for somata and 0.91 +/- 0.07 per 100 micrometer(2) for dendrites) were similar to the densities of contacts reported for alpha-motoneurones. Monoaminergic varicosities in apposition to dendrites greatly outnumbered those on the somata. The density of DBH appositions was consistently lower - corresponding means were 53% and 62% of those for 5-HT on the somata and dendrites, respectively. It is concluded from an analysis of the distribution and density of varicosities in apposition to the gamma-motoneurones compared with the density in the immediate surround of the dendrites that there is indeed both a serotoninergic and noradrenergic innervation of gamma-motoneurones.

Animals↗
PubMed2000

Areas of operation of interneurons mediating presynaptic inhibition in sacral spinal segments.

Sources of primary afferent depolarization (PAD) of skin afferents in the sural (Sur) nerve and of group-II muscle afferents in the posterior biceps and semitendinosus (PBST) nerve were compared at several sites, about 2 mm apart, within the L7-S2 segments in order to define areas of projection of sacral interneurons mediating PAD of these afferents. Just rostral to the pudendal nucleus, strong PAD of Sur afferents was evoked by stimulation of skin nerves, while stimulation of muscle nerves had only marginal effects. This indicates that sacral PAD interneurons co-excited by skin and muscle afferents operate primarily within the regions overlying the pudendal nucleus. Furthermore, PAD evoked by muscle afferents was weaker over the rostral part of the pudendal nucleus than over the caudal part of this nucleus, where hamstring afferents became its main source, both in Sur and in PBST group-II afferents. By correlating the relative strength of PAD at the levels of the rostral and caudal parts of the pudendal nucleus with the previously established input from muscle and cutaneous afferents to interneurons at these levels, it is therefore proposed that sacral PAD interneurons operate over shorter distances than indicated by previous experiments: over either rostral or caudal parts of the pudendal nucleus, i.e., about 2 mm, rather than over the whole length of this nucleus, i.e., 4-5 mm. Sacral PAD interneurons may, thus, modulate synaptic transmission to even more spatially restricted neuronal populations than previously proposed.

Action Potentials↗
PubMed2000

Nociceptive input to ascending tract neurones forwarding information from low threshold cutaneous and muscle afferents in cats.

Effects of noxious skin stimulation (central foot pad and foot dorsum) by radiant heat were tested on neurones of ascending tracts with a main input from non-nociceptors. The dominating effect on ventral spinocerebellar tract neurones was a depression (mainly from the pad). Responses of spinocervical tract neurones were either facilitated (predominantly from the foot dorsum) or depressed (predominantly from the pad). The dominating effect on neurones tentatively classified as dorsal horn dorsal spinocerebellar tract neurones was facilitatory from both skin areas. Similar effects were evoked by selective actions of C-fibres when A-delta fibres were blocked by TTX.

Afferent Pathways↗
PubMed2000

Nociceptive input to spinal interneurones in reflex pathways from group II muscle afferents in cats.

Effects of noxious stimulation of the skin by radiant heat were tested on responses of first order interneurones in reflex pathways from group II muscle afferents in mid-lumbar, lower-lumbar and sacral segments of the spinal cord. In mid- and lower-lumbar segments both background discharges and monosynaptically evoked responses of intermediate zone interneurones were facilitated. Those of mid-lumbar dorsal horn interneurones were also facilitated suggesting that both these interneuronal populations contribute to the facilitation of flexion reflexes by nociceptors. In contrast, the dominating effects of noxious heat on sacral dorsal horn group II interneurones were inhibitory. The effects evoked by selective activation of C fibres, after A-delta fibres had been blocked by TTX, were similar to those obtained before TTX application.

Action Potentials↗
PubMed2000

Serotoninergic and noradrenergic axonal contacts associated with premotor interneurons in spinal pathways from group II muscle afferents.

We investigated the possibility that monoaminergic axons make contacts with spinal interneurons which project to motor nuclei and are monosynaptically activated by group II muscle afferents. Interneurons in midlumbar spinal segments of adult cats were characterized electrophysiologically and intracellularly labelled with tetramethylrhodamine dextran. Serotoninergic and noradrenergic axons were identified with immunofluorescence in sections containing labelled cells. Contacts between monoaminergic axons and interneurons were investigated with three-colour confocal laser scanning microscopy and analysed with a computer reconstruction program. Cell bodies and dendritic trees of five cells were reconstructed and putative contacts were plotted. The average number of contacts formed by serotoninergic axons was 140 and the average number of noradrenergic contacts was 38. The majority (95%) of contacts were formed with dendrites; these were distributed over the entire dendritic tree, even on the most distal branches. These findings provide a morphological basis for the modulatory actions of monoamines on premotor spinal interneurons in pathways from group II muscle afferents.

Animals↗
PubMed2000

Effects of monoamines on interneurons in four spinal reflex pathways from group I and/or group II muscle afferents.

Effects of locally applied serotonin (5-HT) and noradrenaline (NA) were tested on extracellularly recorded responses of single spinal interneurons in deeply anaesthetized cats. These effects were tested on: (i) interneurons mediating reciprocal inhibition from group Ia afferents; (ii) interneurons mediating non-reciprocal inhibition from group Ia and Ib afferents; (iii) intermediate zone interneurons co-excited by group I and II afferents; and (iv) dorsal horn interneurons excited by group II afferents. Effects of monoamines were tested on responses evoked at latencies compatible with monosynaptic coupling. Responses evoked by group Ia and/or Ib muscle afferents were facilitated in all of the tested interneurons both by NA and 5-HT. Responses evoked by group II muscle afferents were depressed in the majority of the interneurons but were facilitated in some of them. 5-HT depressed these responses in all dorsal horn interneurons and in one subpopulation of intermediate zone interneurons, while it facilitated them in another subpopulation of intermediate zone interneurons. NA depressed them in all intermediate zone interneurons and in one subpopulation of dorsal horn interneurons, while it facilitated them in another subpopulation of dorsal horn interneurons. The results of this study lead to the conclusions that: (i) modulation of synaptic actions of muscle spindle and tendon organ afferents on spinal interneurons by 5-HT and NA is related to both the type of the afferent and the functional type of the interneuron; and that (ii) 5-HT and NA counteract each others' actions on some interneuronal types but mutually enhance them on the others.

Afferent Pathways↗
PubMed2000

Microsatellite instability in thyroid papillary carcinoma and multinodular hyperplasia.

Microsatellite instability (MSI) is a molecular landmark of mutations in DNA mismatch repair genes. The impaired efficiency of DNA repair mechanisms promotes carcinogenesis as well as contributes to tumour progression. Until now, only few studies on MSI in thyroid tumours have been published. Therefore, the aim of the present study was to investigate MSI as a possible characteristic feature of thyroid tumours. The analysis of 12 thyroid papillary carcinomas and 17 multinodular hyperplasias at 13 microsatellite loci showed MSI and loss of heterozygosity (LOH) in both types of lesion, with more alterations noted in the papillary thyroid carcinomas (in 65%) than in multinodular hyperplasia (in 35%). In carcinomas, LOH occurred more frequently than MSI, while in multinodular hyperplasia the LOH/MSI ratio is almost equal.

Adolescent↗
PubMed2000

[Bone mineral density of adults living in the city of Wrocław compared with the reference ranges].

Certain elements of lifestyles (distinctive for the particular population) are presumed to influence on bone metabolism. This fact results in considerable differences between various populations, concerning both the occurrence of the normal variability of BMD (bone mineral content) among adult and elderly men and women, and also the prevalence of osteopenia or osteoporosis. The purpose of the study was to evaluate the variability of BMD in a group of healthy and occupationally active inhabitants of the city of Wroclaw, Poland (426 men aged 20-59 and 1218 women aged 20-62) and to compare our results with the reference ranges provided by the producer of the Stratec 960 apparatus. Trabecular and total BMD at the distal radius of the nondominant hand were assessed by peripheral Quantitative Computed Tomography (pQCT) using the Stratec 960 apparatus. BMD of Polish men and women significantly differ from the reference ranges of Stratec 960. The unfavourable phenomenon of the greater BMD decline with age, as compared to the standard values provided by the producer of the device, occurred. It should also be stressed that this reduction is more intense with age and it is marked among men older than 36. Taking into consideration the fact, that our material comprises only occupationally active subjects, the revealed differences would be probably greater, if they were evaluated in Polish population as a whole (our sample does not include persons, who are retired from the healthy conditions). Considering those significant discrepancies between our data and the Stratec reference population, one should be careful when using the normative database provided by Stratec for the densitometric diagnosis of osteoporosis among Polish women and men. Additionally the present study reveals that BMD (and its age-related changes during normal aging) is one of the features characteristic for the particular regional population, which is due to inter-populational differences of those elements of lifestyle, which can influence both general health condition and bone mineral density.

Adult↗
PubMed1999

Filtration properties of nonwovens.

This paper presents the results and conclusions from experimental investigations concerning filtration properties of nonwovens. The needled nonwovens were made from polyester fibres (PTE) with average fibre diameter 12 micrometres and polypropylene fibres (PP) with average fibre diameter 32 micrometres. Nonwovens were produced out of each of those fibres or out of a mixture of polyester and polypropylene fibres. This paper also presents investigations of nonwoven fabric made of polypropylene fibres (PP) with average fibre diameter 2.6 micrometres, which was formed according to melt-blown technology. Oil mist, as challenge aerosol, was used to evaluate the performance of filter media at various aerosol velocities. The average oil mist test aerosol particle diameter was 0.3 micrometre. Filter penetration was measured at oil mist concentration 0.24 g/m(3).

Aerosols↗
PubMed1999

Expression of a selenomethionyl derivative and preliminary crystallographic studies of human cystatin C.

Human cystatin C, a protein with amyloidogenic properties and a potent inhibitor of papain-like mammalian proteases, has been produced in its full-length form by recombinant techniques and crystallized in two polymorphic forms: cubic and tetragonal. A selenomethionyl derivative of the protein, obtained by Escherichia coli expression and with complete Met-->Se-Met substitution confirmed by mass spectrometry, amino-acid analysis and X-ray absorption spectra, was crystallized in the cubic form. A truncated variant of the protein, lacking ten N-terminal residues, has also been crystallized. The crystals of this variant are tetragonal and, like the two polymorphs of the full-length protein, contain multiple copies of the molecule in the asymmetric unit, suggesting oligomerization of the protein.

Amino Acid Sequence↗
PubMed1999

[The deterioration of the parameters of the human semen: myth or reality?].

Numerous publications in the world's literature on the base of multiply retrospective analyses suggest a population-wide decline in the quality of human semen over the past 50 years. The average sperm density, the mean sperm volume and the percentage of the typical spermatozoids appear to have decreased. Furthermore, a significant increase in the incidence of both genitourinary abnormalities (hypospadiasis, cryptorchidism) and testicular cancers in the general population has been reported. The data vary among different geographic regions. The possible adverse effect of the environmental pollutants with oestrogenic activity on male reproductive ability has been considered. These chemicals can affect the foetal development of male gonads and also impair testes during maturity, which finally results in disturbances in testicular functions and leads to the reduction of male fertility.

Adult↗
PubMed1999

[Testosterone and atherosclerosis in males during andropause].

Nowadays besides the commonly accepted atherogenic risk factors a special emphasis is laid on the significance of testosterone in atherogenesis in men which physiologic deficit during "andropause" is able to promote this pathology. An elevated estradiol:testosterone ratio seems to be an independent risk factor of atheromatous heart complications. There is a proved positive correlation between free testosterone, total testosterone, dihydrotestosterone and HDL-cholesterol, apoA1 apolipoprotein. The relationship between LDL-cholesterol, VLDL-cholesterol, total cholesterol and total and free testosterone seems to be unanimous, but in certain studies the beneficial influence of testosterone on the mentioned lipids has been observed. The discussed hormone is also functionally connected with coagulation and fibrynolisis; a positive correlation was found between endogenous testosterone and tPA-Fx and a negative correlation between testosterone and PAI-1, fibrinogen, D-dimers, alpha 2-antiplasmin. Testosterone is a functional regulator of the vascular tonus and influences on reological properties of microcirculation (the application of testosterone infusion into canine coronary arteries causes the dilatation of main and the small vessels, through NO syntetase induction and ATP-dependent K(+)- channel activation). A statistically significant positive correlation between testosterone and insulin has been stated (an elevated oestradiol:testosterone ratio is connected with the insulin resistance). Additionally a negative relationship between testosterone and android obesity has been observed. Although nowadays there are more and more facts proving the benefits of the retaining the proper testosterone levels in aging men, the final influence of the testosterone supplementary therapy on atherogenesis is not solved.

Adult↗
PubMed1999

[On the healthy male aging: hormonal aspects].

Authors present select problems performed in the "Geneva Manifesto" published by the International Society for the Study of the Aging Male in February 1998 and pay the special attention on the inaccuracy connected with a commonly used name andropause. Additionally they present actual metabolic and clinical aspects resulting from the hormonal disturbances in aging men (hypotestosteronemia, decline in DHEA and hGH).

Aged↗
PubMed1998

Modulation of information forwarded to feline cerebellum by monoamines.

The reported results demonstrate that monoamines modulate activity of three populations of spinocerebellar tract neurons that are rhythmically active during locomotion. However, information on dynamic changes in muscle length and tension (signaled by muscle spindle primary afferents and tendon organs) and on the absolute length of muscles (signaled by muscle spindle secondary afferents) is differently modulated. The transfer of the former is facilitated but that of the latter is either facilitated or depressed; it is facilitated via Clarke's column dorsal spinocerebellar tract neurons and depressed via dorsal horn dorsal spinocerebellar tract neurons. The effects of noradrenaline and serotonin are similar.

Animals↗
PubMed1998

New observations on coupling between group II muscle afferents and feline gamma-motoneurones.

1. Extra- or intracellular recordings were made from seventy-six gamma-motoneurones of hindlimb muscles in chloralose anaesthetized cats to re-assess the coupling between secondary muscle spindle afferents (group II muscle afferents) and these neurones. The latencies of a number of responses evoked by group II muscle afferents in gamma-motoneurones were shorter than minimal latencies of responses induced disynaptically in other spinal neurones. These latencies are therefore compatible with monosynaptic coupling between muscle spindle secondaries and gamma-motoneurones. 2. Responses fulfilling criteria for monosynaptically evoked responses were seen in about one third of gamma-motoneurones with input from the group II muscle afferents tested (in 6 of 18 motoneurones recorded intracellularly and in 26 of 74 motoneurones recorded extracellularly). They were usually evoked from only one of the stimulated nerves, stimulation of group II afferents of other nerves being followed by responses at longer latencies. 3. Most gamma-motoneurones were excited by group II afferents from several muscles, both flexors and extensors. However, a comparison of group II input to gamma-motoneurones innervating medial gastrocnemius and four other hindlimb muscles revealed differences in both incidence and sources. 4. This study extends results of previous studies by providing evidence that some synaptic actions of group II afferents, including afferents from the same muscle, are evoked monosynaptically, and may assist in sustaining the activation of gamma-motoneurones by positive feedback.

Animals↗