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Biomedical subjects

Andrzej Wróbel

Publications and source records attributed to Andrzej Wróbel.

At least 19 recordsLinked to original sources
PubMed2005

Cortical modulation of neuronal activity in the cat's lateral geniculate and perigeniculate nuclei.

The cortico-thalamic influence on spontaneous and visually evoked activity of single cells in the dorsal lateral geniculate (LGN) and perigeniculate (PGN) nuclei were examined in unanesthetized cats with pretrigeminal brainstem transections by means of reversible cooling of cortical areas 17 and 18. The spatio-temporal characteristic of cells' RFs was tested with light spot randomly presented at different points along the receptive field axis. The cessation of cortical input decreased spontaneous activity of most of the LGN cells (64%; as compared to 36% with increased background firing). Similarly, their visually evoked responses were reduced (70% cells; compared to 24% with increased response) and extent of central excitatory domains diminished. In contrast, the majority of PGN neurons increased their spontaneous activity (62%; compared to 38% with decreased firing rate). Cortical cooling resulted also in a decrease of the ON and OFF central responses of most PGN cells (55%; as compared to 20% with increased responses). The described effects were more pronounced within the population of cells in X than in Y pathway. Although the removal of descending cortical excitation disturbed the balance of activity within the network of thalamic cells the gain of the geniculate relay was preserved. We conclude that the main role exerted by the cortico-thalamic pathway serves facilitation of the ascending retino-cortical flow of visual information at the level of lateral geniculate nucleus.

Animals↗
PubMed2005

Collagen deposition around polypropylene tapes implanted in the rectus fascia of female rats.

OBJECTIVE: Implantation of the mesh induces a foreign-body reaction followed by the development of connective tissue that may alter tape property. The aim of our study was to evaluate the deposition of collagen in the vicinity of monofilament tension-free vaginal tape (TVT; Ethicon Inc., Johnson & Johnson) and multifilament intravaginal slingplasty (IVS; Tyco Healthcare) polypropylene tapes implanted in female rats. METHODS: The samples of the meshes (10 mg each) were implanted in the rectus fascia of 14 Wistar female rats and removed after 42 days. Collagen was extracted with 0.5 M acetic acid and subsequently with pepsin (1 mg/ml in 0.5 M acetic acid). Collagen concentration was measured using Sircol Collagen Assay (Biocolor Ltd.) and normalised for milligrams of tape weight. For histological examination, tape samples were stained with haematoxylin and eosin or with silver for type III collagen. RESULTS: The total amount of collagen extracted did not differ significantly between TVT and IVS samples. For both tapes, extraction with acetic acid yielded a higher amount of collagen (about 70%) than extraction with pepsin. On histological examination, less densely packed bundles of collagen fibres and a slightly more intense inflammatory reaction were observed with TVT compared with IVS mesh. CONCLUSION: The total amount of collagen deposited around the polypropylene mesh implanted in female rats was similar for TVT and IVS meshes, but differences were noted in the arrangement of the collagen fibres and the intensity of the inflammatory reaction.

Animals↗
PubMed2005

The need of neuroinformatic approach in functional neurophysiology.

Despite the enormous growth in the number of facts and regularities observed in neuroscience, the current state of the field does not allow their integration in coherent theoretical frameworks. Neuroinformatics is a new research field devoted to development of neuroscience data bases together with computational models and analytical tools for sharing, integration and analysis of experimental data and the advancement of theories of nervous system function. From 1996 the OECD countries promote fostering neuroinformatics by eliminating the barriers that prevent cooperation and by providing incentives to potential participants. This activity was formulated in the Report on Neuroinformatics from The Global Science Forum Neuroinformatics Working Group of the OECD (2002) as well as in several printed publications by the Neuroinformatics group (Amari et al. 2002, Eckersley et al. 2003). This article summarizes the ideas presented in the Report and stresses the importance of analytical and modeling approach to functional neurophysiology.

Electroencephalography↗
PubMed2005

Local classifiers for evoked potentials recorded from behaving rats.

Dynamic states of the brain determine the way information is processed in local neural networks. We have applied classical conditioning paradigm in order to study whether habituated and aroused states can be differentiated in single barrel column of rat's somatosensory cortex by means of analysis of field potentials evoked by stimulation of a single vibrissa. A new method using local classifiers is presented which allows for reliable and meaningful classification of single evoked potentials which might be consequently attributed to different functional states of the cortical column.

Algorithms↗
PubMed2005

[Classification and surgery for uterovaginal anomalies].

Maldevelopment of the müllerian ducts occurs in a variety of forms, and each anomaly is distinctive. Nevertheless, some generalizations can be made. A comprehensive preoperative evaluation of patients with suspected uterovaginal malformations is essential, but a clear understanding of the particular anomaly may not be established until the time of surgical correction. It is essential to exclude other then anatomical causes of procreative misfortunes before making the decision dealing with surgical correction of a given uterovaginal anomaly.

Adnexa Uteri↗
PubMed2004

Estrogen receptor alpha and beta expression in uterine leiomyomas from premenopausal women.

OBJECTIVE: To measure messenger RNA levels of estrogen receptor (ER) alpha and beta in uterine leiomyomas, normal myometrium, and endometrium. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): Seventeen premenopausal women who underwent surgery due to symptomatic uterine leiomyomas. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Quantitative RT-PCR was used for evaluation of ERalpha and ERbeta expression. Results were normalized to total cellular DNA. RESULT(S): Expression of ERalpha and ERbeta did not differ between leiomyomas and myometrium; however, in both tissues, expression of ERalpha was significantly higher than that of ERbeta. Estrogen receptor-alpha expression in endometrium was lower than in leiomyomas and myometrium. In leiomyomas and endometrium, correlations between expression of ERalpha and ERbeta were found. CONCLUSION(S): Uterine leiomyomas, myometrium, and endometrium display distinct patterns of ER expression.

Adult↗
PubMed2004

Increased mitogen-induced lymphocyte proliferation in treatment resistant depression: a preliminary study.

BACKGROUND: The biological basis of treatment resistance in depression still remains unclear. Some studies suggest that there exists a relationship between a disturbance in the immune system and depression. AIMS: To investigate the immune status of patients with treatment resistant depression, we compared the in-vitro lymphocytic responses to three different mitogens in 10 drug-free patients with treatment resistant depression and 10 normal controls matched for age and sex. RESULTS: We observed a marked increase in the lymphocyte mitogenic activity to mitogens of T lymphocytes. DISCUSSION: This activation of lymphocyte function may be indicative of a pathological stimulation in cell-mediated immunity in patients with treatment resistant depression.

Adult↗
PubMed2004

[Non-penetrating deep sclerectomy in the treatment of advanced cases of open angle glaucoma].

PURPOSE: The purpose of the paper was to examine the efficacy of non-penetrating deep sclerectomy (NPDS) with sodium hyaluronate implants and mitomycin C in the treatment of advanced cases of open angle glaucoma. MATERIAL AND METHODS: Thirty-five eyes of 35 patients with medically uncontrolled advanced open angle glaucoma were retrospectively analyzed. Visual acuity and intraocular pressure measurement were performed before and after surgery at 1 and 7 days and 1, 6 and 12 months. Visual field was analyzed before and 12 months after surgery. RESULTS: The mean preoperative intraocular pressure was 27+/-3.1 mm Hg and 18.1+/-1.5 at 12 month after surgery (p<0.05). Visual acuity decreased more than two rows on Snellen chart in 4 patients. Visual field analysis shows mean defect MD--17+/-5.2 before surgery and 20.1+/-6.2 after 12 month of follow up (p>0.05). Complete success rate defined as an IOP lower than 21 mmHg without medications was 51%. In 3 eyes we performed needling and in 8 goniopuncture. Postoperative complications included hyphaema in 3 eyes, choroidal detachment in 1 eye, bleb fibrosis in 2 eyes. CONCLUSIONS: 1. Deep sclerectomy with SK-GEL implant and antimetabolites provided good reasonable control of intraocular pressure. 2. In uncomplicated cases it let us achieve stabilization of the visual field.

Anti-Bacterial Agents↗
PubMed2004

[Use of scanning laser ophthalmoscope and scanning laser polarimeter in diagnosis and monitoring of early stages of primary open-angle glaucoma].

PURPOSE: To evaluate the usefulness of scanning laser ophthalmoscope (TopSS) and scanning laser polarimeter (GDx) in diagnosis and monitoring patients suspected of primary open angle glaucoma (POAG). MATERIAL AND METHODS: In eighty eyes of 40 patients, we performed TopSS, GDx and static perimetry (Octopus 123) in the time period of three years. RESULTS: The GDx analysis showed progression of changes in the retinal fiber thickness in 28 (35%) eyes (p<0.05). In 18 eyes we found non-specific changes in GDx examinations, which were related to no glaucomatous reason. TopSS analysis of the optic nerve head revealed progression in c/d in 16 (20%) eyes (p<0.05). In seven eyes we detected changes in the visual field, which were more strongly connected with changes in TopSS than GDx. CONCLUSIONS: 1. The TopSS and GDx examinations enabled diagnosis and monitoring of early glaucomatous changes in the period of observation. 2. The GDx examination seems to be more sensitive, and TopSS more specific to glaucoma.

Adult↗
PubMed2004

[Mineralization of homograft aortic valves stored in a nutrient solution].

BACKGROUND AND AIM OF THE STUDY: Mineralization of the homograft aortic valve cusps is a complex process leading to their degeneration and decreasing durability. Factors that play a decisive role in regulation of mineralization, growth of hydroxyapatite crystals are still open questions. We studied development of mineralization in the homograft aortic valves prepared for transplantation stored in the Parker's solution with antibiotics. METHOD: The aortic valves were explanted from 12 donors <18 hours after death. All the cusps were divided into halves. One half of each cusp was stored in the Parker's solution with antibiotics for 28 days at 4 degrees C. Concentrations of several elements (P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn i Sr) in incubated and control samples were determined using energy dispersive X-ray fluorescence (ED-XRF). RESULTS: The study showed that the concentration of Ca and Ca/P increased during incubation that may indicate development of mineralization. CONCLUSIONS: The homograft aortic valve cusps underwent mineralization during in vitro incubation. This may aggravate mineralization in the aortic valve recipients and decrease valve durability which indicate a need for modification of storing condition.

Adult↗
PubMed2003

Sorting functional classes of evoked potentials by wavelets.

Evoked potentials (EPs) recorded within the primary sensory cortex of non-anesthetized rats vary considerably with each peripheral stimulation. We have previously shown that most of this variance reflects the shift of cortical activation between habituated and aroused states. Here we show that a method of matching the potential's course by wavelet functions can reliably differentiate single EPs and may therefore, be used as a probe for indicating the current activation state of the cortex.

Animals↗
PubMed2003

Attention-dependent coupling between beta activities recorded in the cat's thalamic and cortical representations of the central visual field.

We have previously proposed that enhanced 16-24 Hz (beta) local field potential activity in the primary visual cortex and lateral geniculate nucleus may be an electrophysiological correlate of the attentional mechanism that increases the gain of afferent visual information flow to the cortex. In this study, we measured coupling between beta signals recorded in the thalamic (i.e. lateral geniculate or perigeniculate) and cortical representations of the central visual field (within 5 degrees from area centralis), during visual and auditory attentive situations. Signal coupling was calculated in two ways: (i) by means of crosscorrelation between raw beta activities, which depends primarily on phase coherence, and (ii) by phase-independent crosscorrelation between amplitude envelopes of beta activities. Mean amplitudes of raw signal cross correlations obtained for thalamo-cortical recording pairs were not significantly different when calculated during behavioural demands for either visual or auditory attention. In contrast, amplitudes of envelope cross correlations obtained during behaviour requiring visual attention were, on average, two times higher than those calculated during the auditory task. This attention-related coupling emerged from synchronized amplitude modulation of beta oscillatory activity that occurs within the cortico-thalamic circuit involved in central vision.

Acoustic Stimulation↗
PubMed2003

Neuroprotective effect of ACTH (4-9) in degeneration of hippocampal nerve cells caused by dexamethasone: morphological, immunocytochemical and ultrastructural studies.

Sustained exposure to glucocorticosteroids (GCs), adrenal hormones secreted during stress, can cause neural degeneration. This is particularly so in the hippocampus, a principal neural target site for GCs. The purpose of this research was an assessment of the neuroprotective effect of ACTH (4-9) in degenerative changes of hippocampal neurons induced by synthetic GC-dexamethasone. Experiments were conducted on male Albino-Swiss mice. We studied the morphology of neurons in the dorsal hippocampus in slides stained with cresyl violet. Immunocytochemical analysis was carried out with the use of monoclonal antibody anti-MAP2 in order to detect alterations in the neuronal cytoskeleton. We also performed ultrastructural examinations of hippocampal neurons. Quantitative analysis of morphological changes was completed using a computer analyser of histological pictures. It was shown that dexamethasone administered in toxic doses evokes neuronal death in layer CA3 of the hippocampus. Results indicate that ACTH (4-9) shows protective effects in that model. Dexamethasone-induced damage to hippocampal pyramidal neurons (assessed by cell counts, immunocytochemical analysis of cytoskeletal alterations and ultrastructural studies) was significantly reduced in animals administered ACTH (4-9).

Adrenocorticotropic Hormone↗
PubMed2003

Cortical contribution to sensory volleys recorded at thalamic nuclei of lemniscal and paralemniscal pathways.

In order to elucidate the role of cortical input on sensory information processing in different thalamic somatosensory nuclei we recorded potentials evoked (EPs) by whisker deflections of short duration from ventral posteromedial (VPm) and medial posterior (POm) nuclei while manipulating cortico-thalamic activity by means of local cooling, lidocaine application or electrical stimulation. It appeared that only the earliest sub-component of the first negative wave of the EPs resulted from peripheral input, while the rest of the potential's negativity depended on cortical feedback. The latencies and amplitudes of EPs recorded at both nuclei were not significantly different, which might be attributed to urethane anesthesia.

Animals↗
PubMed2003

[Tissue reaction to polypropylene mono-or multi-filament tapes used in surgical techniques of stress urinary incontinence treatment].

OBJECTIVES: The "gold standard" in surgical treatment of stress urinary incontinence (SUI) is sling operation with polypropylene tape appliance under the mid urethra. There are two types of polypropylene tape which are the most popular nowadays. These two tapes are differently knitted so they have different biomechanical features. The TVT tape is monofilament, rarely knitted and highly elastic but the IVS mesh is multifilament, densly knitted and has only little possibility to stretch. The aim of our study was to assess the tissue reaction to the mono-(TVT) and multifilament (IVS) tapes. MATERIAL AND METHODS: The 10 mm x 10 mm pieces of TVT and IVS tapes were implanted inlay the fascia of musculus abdominis rectus of 14 rat females (2 groups of 7 animals). The tapes with the margin of surrounding fascia were taken off after 6 weeks of healing. All samples were fixed in 10% Formaldehyde in phosphate buffered saline and embedded in paraffin. Four micron tissue sections were stained with hematoxylin and eosin, the reticulin silver impregnation stain according to Gomori (for collagen type III) and periodic acid Schiff and alcian blue (for proteoglycan). RESULTS: In all sections filaments visible as elipsoids were surrounded by resorptive granulation with large multinucleated giant cells like around "foreign body". The diameter of monofilaments was about 150 microns. The connective tissue in the vicinity of mesh was rich of inflammatory cells like histiocytes, lymphocytes, a few polymorphonuclear leucocytes as well as adipocytes and fibroblasts. The large multinucleated giant cells adjacent to monofilaments were relatively bigger than these cells around multifilaments. Moreover, this granulation tissue has a lot of new blood vessels and collagenous fibrous tissue. The multifilaments were about 40 microns in diameter. The inflammatory granulation infiltrated aggregates of multifilaments. This tissue had only few inflammatory cells in comparison to tissue around monofilaments. The large multinucleated giant cells apposed to the mesh were small and collagen created thicker, more compacted bundles. CONCLUSION: The multifilament polypropylene tape induces weaker inflammatory tissue reaction than monofilament mesh. The thicker and more compacted collagen bundles are created around multifilaments so the natural tensile strength of the surrounding tissue is probably higher.

Animals↗
PubMed2002

[Functional analysis of evoked potentials in rat sensory cortex].

In the barrel cortex of behaving rat potentials evoked to vibrissa stimulation are composed from two main principal components which can be attributed to activation of two pyramidal cell populations: supra- and infragranular. The classical aversive stimulus favors the appearance of EPs dominated by a component characteristic of infragranular cells. We hypothesize that neuromodulatory action elicited by contextual stimulation activates all involved cortical neurons which results in opening the transmission gate to the surrounding columns.

Animals↗
PubMed2002

[Assessment of the reliability of different methods in diagnosing endometrial cancer].

OBJECTIVES: Endometrial cancer is the most common gynecologic malignancy. The purpose of the study was to compare the reliability of different methods for diagnosing endometrial cancer. DESIGN: A prospective study from January 1996 to September 1998. MATERIALS AND METHODS: 264 women at risk of endometrial cancer with clinical indications for hysteroscopy with curettage participated in the study. They underwent different diagnostic methods: endometrial cytology (121 cases), endometrial biopsy (150) or ultrasonography (200). The accuracy of these methods was related to the following results obtained from hysteroscopy with curettage. RESULTS: The results of the study suggest higher reliability of endometrial biopsy from cytology. The hysteroscopic diagnosis conforms with the histologic examination showed by the curettage. Endometrial cancer as the cause of post-menopausal bleeding can be excluded in cases with endometrial thickness of < or = 5 mm measured by vaginal ultrasonography. CONCLUSIONS: We concluded that the combination of hysteroscopy and endometrial biopsy may substitute for curettage and become the method of choice for the endometrium.

Adult↗