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Biomedical subjects

T Kowalski

Publications and source records attributed to T Kowalski.

At least 19 recordsLinked to original sources
PubMed2006

Endoscopic sphincterotomy with or without cholecystectomy for choledocholithiasis in high-risk surgical patients: a decision analysis.

BACKGROUND: Laparoscopic cholecystectomy (LC) is recommended for patients with choledocholithiasis after ERCP with sphincterotomy (ES) and stone extraction. AIM: We designed a decision model to address whether ES alone versus ES followed by LC (ES + LC) is the optimal treatment in high-risk patients with choledocholithiasis. METHODS: Our cohort were patients with obstructive jaundice who have undergone an ES with biliary clearance. Recurrent biliary complications over a 2-year period stratified by gallbladder status (in/out) and age-stratified surgical complication rates were obtained from the literature. Failure of therapy was defined as either recurrent symptoms or death attributed to biliary complications. RESULTS: For age 70-79 years, ES failed in 15% whereas ES + LC failed in 17% of cases. Mortality in the EC + LC group was 3.4 times that of the ES alone cohort. For age 80+ years, ES was dominant with an incremental success rate of 8%. Mortality in the ES + LC was 7.6 times that of ES. For age <70, ES + LC was the dominant strategy with an incremental success rate 5%. Sensitivity analysis in the groups confirmed our conclusions. CONCLUSIONS: Management of choledocholithiasis by ES and stone clearance, but without cholecystectomy, should be considered for patients aged 70+. For low-risk patients, ES + LC should be performed to prevent recurrent biliary complications.

Aged↗
PubMed2006

A survey of oesophageal cancer: pathology, stage and clinical presentation.

BACKGROUND: Oesophageal adenocarcinoma is the sixth leading cause of cancer-related mortality worldwide. Previously, oesophageal cancer was mainly squamous cell, presenting late with dysphagia and weight loss. AIMS: To examine the distribution of oesophageal cancer histopathology at a large, urban hospital; to determine the tumour stage and symptoms at presentation; and to evaluate the impact of endoscopic surveillance in Barrett's oesophagus. METHODS: From 1999 to 2004, all patients diagnosed with oesophageal cancer were evaluated retrospectively for demographics and tumour stage at presentation using endoscopic ultrasonography and computerized tomography. RESULTS: A total of 131 patients were included. 81% of tumours were adenocarcinomas; most localized to the distal oesophagus (97%). Patients presented with dysphagia (56%), pain (30%) and/or weight loss (16%). Irrespective of histology, locally advanced lesions accounted for most cases. Thirteen patients had lesions detected in Barrett's surveillance; these were early or intermediate stage in nine patients, but late stage in four patients. CONCLUSIONS: Adenocarcinoma has become the dominant histologic subtype, comprising 81% of proven malignancies. Despite a change in histopathology, most cancers are diagnosed at an advanced stage, presenting with dysphagia, pain and/or weight loss. Endoscopic surveillance of Barrett's oesophagus allows earlier diagnosis of cancer in most, but not all, patients.

Adenocarcinoma↗
PubMed2005

Mapping auditory cortex in the La Plata dolphin (Pontoporia blainvillei).

This study deals with the mapping of the primary and secondary auditory cortex. Due to their important role in echolocation they were the first areas to be examined [P.J. Morgane, M.S. Jacobs, in: R.J. Harrison (Ed.), Functional Anatomy of Marine Mammals, Comparative Anatomy of the Cetacean Nervous System, vol. 1, Academic Press, London, 1972, pp. 117-144]. We analysed the brain of a La Plata dolphin (Pontoporia blainvillei), which had been fixed in formaldehyde, embedded in paraffin, cut in sections of 20mum thickness and stained with cresyl violet. The experimental approach being impossible, we used cytoarchitectonic variations in the neocortex. Former electrophysiological data [T.F. Ladygina, A.Y. Supin, Localization of the projectional sensory areas in the cortex of the porpoise Tursiops truncates, Zh. Evol. Biokhim. Fiziol. 13 (1978) 712-718] [Sokolov, T.F. Ladygina, A.Y. Supin, Location of sensory zones in cerebral cortex of dolphin, Dokl. Biol. Sci., Russian Original 202 (1-6) (1972)] provided the framework for the exact determination of borders between functional cortical areas. We used a stereological observer-independent procedure based on changes in volume density of cell bodies throughout the neocortex [A. Schleicher, et al., Stereological approach to human cortical architecture: Identification and delineation of cortical areas, J. Chem. Neuroanat. 20 (2000) 31-47]. Due to the computer program's high sensitivity to changes in volume density it was possible to analyse the poorly laminated dolphin cortex. The 3D-reconstruction of the auditory cortex was processed using the AMIRA 3.0 Graphics software package comparing the main primary gyri in the histological sections with those in coronal magnetic resonance imaging scans of another intact Pontoporia brain.

Animals↗
PubMed2005

Quantitative architectural analysis: a new approach to cortical mapping.

Recent progress in anatomical and functional MRI has revived the demand for a reliable, topographic map of the human cerebral cortex. Till date, interpretations of specific activations found in functional imaging studies and their topographical analysis in a spatial reference system are, often, still based on classical architectonic maps. The most commonly used reference atlas is that of Brodmann and his successors, despite its severe inherent drawbacks. One obvious weakness in traditional, architectural mapping is the subjective nature of localising borders between cortical areas, by means of a purely visual, microscopical examination of histological specimens. To overcome this limitation, more objective, quantitative mapping procedures have been established in the past years. The quantification of the neocortical, laminar pattern by defining intensity line profiles across the cortical layers, has a long tradition. During the last years, this method has been extended to enable a reliable, reproducible mapping of the cortex based on image analysis and multivariate statistics. Methodological approaches to such algorithm-based, cortical mapping were published for various architectural modalities. In our contribution, principles of algorithm-based mapping are described for cyto- and receptorarchitecture. In a cytoarchitectural parcellation of the human auditory cortex, using a sliding window procedure, the classical areal pattern of the human superior temporal gyrus was modified by a replacing of Brodmann's areas 41, 42, 22 and parts of area 21, with a novel, more detailed map. An extension and optimisation of the sliding window procedure to the specific requirements of receptorarchitectonic mapping, is also described using the macaque central sulcus and adjacent superior parietal lobule as a second, biologically independent example. Algorithm-based mapping procedures, however, are not limited to these two architectural modalities, but can be applied to all images in which a laminar cortical pattern can be detected and quantified, e.g. myeloarchitectonic and in vivo high resolution MR imaging. Defining cortical borders, based on changes in cortical lamination in high resolution, in vivo structural MR images will result in a rapid increase of our knowledge on the structural parcellation of the human cerebral cortex.

Algorithms↗
PubMed2002

Current density threshold for the stimulation of neurons in the motor cortex area.

The aim of this study was to determine a current density threshold for exciting the motor cortex area of the brain. The current density threshold for excitation of nerve fibres (20 microm in diameter) found in the literature is approximately 1 A/m(2) at frequencies lower than 1 kHz. In consideration of a safety factor of 100, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) recommends to restrict the exposure to 0.01 A/m(2). The electromagnetic stimulation of neurons in the motor cortex is used in the clinical diagnosis of nerve lesions and neuropathy by means of magnetic or electrical transcranial stimulation. Combining medical data from clinical studies and technical specifications of the Magstim Model 200 stimulator, we were able to compute the current density threshold for the excitation of the human motor cortex by means of the finite element method (FEM). A 3D-CAD head model was built on the basis of magnetic resonance imaging (MRI) slices and segmented into four anatomical structures (scalp, skull, brain, and ventricular system) with different conductivities. A current density threshold for the stimulation of the motor cortex area of the upper limbs of 6 and 2.5 A/m(2) at 2.44 kHz and 50 Hz, respectively, was calculated. As these values lie above the recommended ICNIRP values by two orders of magnitude there is no need for lower safety standards with regard to stimulation of the brain.

Central Nervous System Diseases↗
PubMed2001

Bioinformatics -- a patenting view.

The use of bioinformatics in the biological sciences has brought about a change in the way that biological inventions can be protected by patent laws. Using approaches developed in the fields of computer science and business, patent applicants now seek to protect certain aspects of their inventions, which include software, methods of doing business and uses of information as well as more traditional biotechnological products and processes. These approaches are useful in resolving some of the difficulties now faced in prosecuting patent applications directed to biological inventions that are claimed in more conventional terms.

Algorithms↗
PubMed2001

Nitric oxide synthase-I containing cortical interneurons co-express antioxidative enzymes and anti-apoptotic Bcl-2 following focal ischemia: evidence for direct and indirect mechanisms towards their resistance to neuropathology.

Neuronal nitric oxide-I is constitutively expressed in approximately 2% of cortical interneurons and is co-localized with gamma-amino butric acid, somatostatin or neuropeptide Y. These interneurons additionally express high amounts of glutamate receptors which mediate the glutamate-induced hyperexcitation following cerebral injury, under these conditions nitric oxide production increases contributing to a potentiation of oxidative stress. However, perilesional nitric oxide synthase-I containing neurons are known to be resistant to ischemic and excitotoxic injury. In vitro studies show that nitrosonium and nitroxyl ions inactivate N-methyl-D-aspartate receptors, resulting in neuroprotection. The question remains of how these cells are protected against their own high intracellular nitric oxide production after activation. In this study, we investigated immunocytochemically nitric oxide synthase-I containing cortical neurons in rats after unilateral, cortical photothrombosis. In this model of focal ischemia, perilesional, constitutively nitric oxide synthase-I containing neurons survived and co-expressed antioxidative enzymes, such as manganese- and copper-zinc-dependent superoxide dismutases, heme oxygenase-2 and cytosolic glutathione peroxidase. This enhanced antioxidant expression was accompanied by a strong perinuclear presence of the antiapoptotic Bcl-2 protein. No colocalization was detectable with upregulated heme oxygenase-1 in glia and the superoxide and prostaglandin G(2)-producing cyclooxygenase-2 in neurons. These results suggest that nitric oxide synthase-I containing interneurons are protected against intracellular oxidative damage and apoptosis by Bcl-2 and several potent antioxidative enzymes. Since nitric oxide synthase-I positive neurons do not express superoxide-producing enzymes such as cyclooxygenase-1, xanthine oxidase and cyclooxygenase-2 in response to injury, this may additionally contribute to their resistance by reducing their internal peroxynitrite, H(2)O(2)-formation and caspase activation.

Animals↗
PubMed2001

[The influence of demographic and behavioral factors on the risk of human papillomavirus infection].

OBJECTIVES: The aim of this work was the assessment of correlation between different types of HPV and chosen factors: the number of pregnancies, childbirths and smoking habits. MATERIALS AND METHODS: Patients were examined in the Gynaecology Clinic, Silesian Medical Academy in Zabrze from 1998 until 2000. They were either hospital patients or women subjected to routine cytological examination. The smears were simultaneously collected for both cytooncologic examination and PCR identification of HPV viruses. Cytological smears were classified according to the Bethesda system. RESULTS: A relationship between the presence of HPV and number of pregnancies or childbirths was confirmed as well as the relationship between smoking and the presence of HPV genome. The higher number of pregnancies or childbirths the higher frequency of HPV presence is. HPV presence was more frequent in the group of smoking women. CONCLUSIONS: A relationship between the presence of HPV and the number of past childbirth or pregnancies was found. The statistically significant correlation between smoking and the risk of HPV infection was also confirmed.

Adult↗
PubMed2000

A stereological approach to human cortical architecture: identification and delineation of cortical areas.

Stereology offers a variety of procedures to analyze quantitatively the regional and laminar organization in cytoarchitectonically defined areas of the human cerebral cortex. Conventional anatomical atlases are of little help in localizing specific cortical areas, since most of them are based on a single brain and use highly observer-dependent criteria for the delineation of cortical areas. In consequence, numerous cortical maps exist which greatly differ with respect to number, position, size and extent of cortical areas. We describe a novel algorithm-based procedure for the delineation of cortical areas, which exploits the automated estimation of volume densities of cortical cell bodies. Spatial sampling of the laminar pattern is performed with density profiles, followed by multivariate analysis of the profiles' shape, which locates the cytoarchitectonic borders between neighboring cortical areas at sites where the laminar pattern changes significantly. The borders are then mapped to a human brain atlas system comprising tools for three dimensional reconstruction, visualization and morphometric analysis. A sample of brains with labeled cortical areas is warped into the reference brain of the atlas system in order to generate a population map of the cortical areas, which describes the intersubject variability in spatial conformation of cortical areas. These population maps provide a novel tool for the interpretation of images obtained with functional imaging techniques.

Brain Mapping↗
PubMed2000

[Comparison of conservative and laparoscopic treatment of PCOS].

OBJECTIVE: Aim of study contained clinical analysis of results conservative (Clostilbegyt) and laparoscopic (electro-catheterisation of ovaries) methods of treatment PCOS. Authors analysed count of pregnancy, deliveries and serum concentrations of LH, FSH, LH/FSH ratio, 17 beta E2 before and after treatment. MATERIAL AND METHODS: Stady included 50 obese patients (group A, BMI > 28) treated by Clostilbegyt and 50 lean patients (group B, BMI < 28) treated by laparoscopic ovarian electrocautery. RESULTS: We found higher percentage of pregnancies (84%) and deliveries in group B (72%) versus A. We obtained statistically significant higher serum concentrations of LH, 17 beta E2 and LH/FSH ratio of group B versus A. CONCLUSIONS: 1. Recommendation method for treatment PCOS is a laparoscopic electro-catheterisation of ovaries. 2. This method stabilize hormonal secretion of hypothalamic-pituitary-ovarian axis in the PCOS.

Adult↗
PubMed2000

[Laparotomy performed in pregnant women due to non-obstetrical causes].

OBJECTIVE: The clinical characteristics of laparotomy during pregnancy were investigated. MATERIALS AND METHODS: A series of 24 cases of laparotomy during pregnancy was investigated with respect to clinicopathologic features and outcome. RESULTS: Among 23 cases there were 20 ovarian tumors, 2 acute appendicitis and 2 uterine fibroid. Gestational ages at the time of surgery ranged from 16 to 24 weeks of patients with ovarian tumors and from 30 to 32 weeks in others. No intraoperative or postoperative maternal or fetal complications occurred. One patient had a stage III ovarian carcinoma and went to total hysterectomy, and other patient had a stage IA ovarian carcinoma. CONCLUSIONS: Appendectomy can be performed without additional risk to the fetus for those who require surgical intervention during pregnancy. Ovarian surgery in pregnancy for persistent masses is important to obtain a final histologic diagnosis.

Appendectomy↗
PubMed1999

Treatment of alcohol withdrawal syndrome with gabapentin.

Four in-patients with moderate alcohol-withdrawal syndromes benefited from treatment with gabapentin administered in an add-on fashion to clomethiazole. In comparison with the amount of clomethiazole required as estimated using a specially developed score during previous detoxifications of these patients at our hospital, gabapentin (400 mg q.i.d.) clearly reduced the amount of clomethiazole needed now Gabapentin, an anticonvulsant with favorable pharmacokinetic properties and tolerability, and with no known risk of dependence, may therefore be a useful new drug in the treatment of alcohol withdrawal. We believe that the potential value of gabapentin in alcohol withdrawal deserves further controlled studies.

Acetates↗
PubMed1998

[The evaluation of susceptibility to oxidation of selected lipoproteins of pregnant women with type B diabetes mellitus in 2nd and 3rd trimester of pregnancy].

OBJECTIVES AND DESIGN: The aim of study was estimation of susceptibility on the process of oxidation of selected lipoproteins of pregnant women with IDDM in II, III trimester of pregnancy. MATERIALS AND METHODS: Study included 80 women. Patients were divided into four groups: pregnant with IDDM, pregnant healthy, nonpregnant with and without IDDM. We used spectrophotometric method for estimation of susceptibility on oxidation of HDL, LDL in the four groups of patients. RESULTS: In the group of diabetic pregnant we found increased serum concentrations of LDL. The comparison of examined groups showed statistically significant higher susceptibility on the oxidation of chosen lipoproteins in pregnant with IDDM. This group of patients characterized lower antioxidation activity than other groups. CONCLUSIONS: Diabetic pregnant characterized higher serum concentrations of LDL, and increase of peroxidation of lipids than other groups. This group showed lower total antioxidation activity. In the groups of diabetic women we obtained increased suspectibility of oxidation LDL and HDL.

Adult↗
PubMed1994

Transcriptional control of rat hepatic glutaminase expression by dietary protein level and starvation.

Mammalian liver possesses a unique isozyme of phosphate-activated glutaminase that is subject to long-term regulation. In rats during starvation or after consumption of diets containing high amounts of protein (60%), hepatic glutaminase activity was 100% higher than in rats fed a 20% protein diet. Conversely, rats fed low protein diets (0 and 5%) had lower hepatic glutaminase activity when compared with rats fed the 20% protein diet. Differences in activity with different dietary protein levels were not due to differences in the amount of food consumed. The relative abundance of mRNA encoding hepatic glutaminase was lower in rats fed 0% protein and higher in those starved or fed 60% protein diet when compared with rats fed the 20% protein diet. The mRNA elongation assay in hepatic nuclei isolated from these animals demonstrated that the rate of transcription of the glutaminase gene was also different in rats starved or fed different levels of dietary protein. Overall, the results indicate that differences in hepatic glutaminase activity in rats starved or fed different levels of protein are mainly due to differences in the rate of transcription of the gene. In this way the regulation of hepatic glutaminase expression is similar to that seen for other enzymes involved in hepatic amino acid catabolism but differs markedly from that of renal glutaminase, in which changes in transcription rate are not observed and alterations of mRNA turnover are the principle mechanism of long-term regulation.

Animals↗