Biomedical subjects

M Urban

Publications and source records attributed to M Urban.

At least 37 records · Page 2Linked to original sources

PubMed2001

Renal morphology in connexin43 knockout mice.

Connexins (Cx) are a family of proteins that constitute the intercellular membrane channels of gap junctions. These junctions permit intercellular movement of ions and other molecules between cells, a property vital to organogenesis. Cx43 is a member of the family of channel-forming proteins that are essential for cell-cell communication of developmental signals. Studies demonstrate that Cx43 is observed in mesenchymal cells of 12-day gestation mouse kidney, a crucial period of renal development. In order to study the significance of Cx43 on renal developmental morphology, we evaluated the kidneys of embryos lacking the gene encoding for Cx43. Polymerase chain reaction (PCR) from tail specimens identified wild-type (WT), heterozygote (HT) and knockout (KO) progeny. In situ RT-PCR displayed abundant Cx43 staining in glomeruli, vasculature, and tubules in kidneys obtained from WT progeny. In contrast, Cx43 expression was completely absent in kidneys isolated from the KO. Renal histology in all three groups displayed no significant differences. Renal size was similar and there was no evidence of dysplasia or cyst formation in the KO. Our results indicate that absence of Cx43, heretofore considered essential for renal development, does not affect early renal morphological development.

Animals↗

PubMed2001

[Stereoscopic simulation of ear surgery intervention with a novel 3D computer models].

INTRODUCTION: The presentation of the surgical anatomy of the temporal bone by standard anatomical figures is not suitable for otosurgical training. For the comprehension of its complex morphology temporal bone drilling is inalienable. Aim of the present cooperation was to gain an interactive real-3D program for the simulation of specific laterobasal surgical approaches. METHODS: The program was derived from a standard horizontal section of a human temporal bone using a Siemens Somatom Plus 4 Tomograph. The slice thickness was 1 mm, the image matrix was 512. The Voxel-Man-system was used to built up the application for unix workstations. RESULTS: Each step of a surgical approach to the temporal bone can be performed by the present computer model. Calculation in a stereo mode even allows spatial 3D-perception when using red/green glasses. CONCLUSIONS: This program is a novel tool to simulate critical aspects of otosurgical procedures on a computer. Up to now the lack of tactile and kinesthetic information does not allow to renounce individual temporal bone drilling.

Computer Simulation↗

PubMed2001

[Magnetic resonance imaging and magnetic resonance arthrography of the acetabular labrum: comparison with surgical findings].

AIM OF THE STUDY: To evaluate the accuracy of magnetic resonance imaging (MRI) and magnetic resonance (MR) arthrography in detecting acetabular labral lesions in correlation to surgical findings. PATIENTS AND METHODS: Forty patients (40 hips) with chronic hip pain and a strong clinical suspicion of labral lesions were examined with MRI in the coronal and axial plane by obtaining T1 weighted and proton density-weighted spin echo sequences. Additionally, MR arthrography of the hip joint in the coronal oblique and sagittal oblique plane was performed by obtaining T1-weighted three-dimensional gradientecho sequences after the intraarticular injection of gadopentate dimeglumine. The labra were prospectively evaluated on the basis of morphology, signal intensity, the presence or absence of a tear, and their attachment to the acetabulum. All patients underwent surgery, and the MRI findings and MR arthrography findings were compared with the surgical results. RESULTS: Surgically, 34 labral lesions, and 6 normal labra were detected. MRI correctly depicted labral lesions in 24 patients and two normal labra, and MR arthrography correctly depicted labral lesions in 30 patients and 5 normal labra compared with the surgical results. The sensitivity of MRI was 80%, the accuracy of MRI was 65%, the sensitivity of MR arthrography was 95%, and the accuracy of MR arthrography was 88%. CONCLUSIONS: MR arthrography enables considerably more accurate detection of acetabular labral lesions than MRI. MR arthrography should be the method of choice for the diagnosis of the presence or absence of acetabular labral lesions in patients with chronic hip pain and a strong clinical suspicion of labral lesions.

Acetabulum↗

PubMed2001

Treatment of benign ureterointestinal anastomotic strictures with permanent ureteral Wallstent after Camey and Wallace urinary diversion: long-term follow-up.

BACKGROUND AND PURPOSE: Ureterointestinal anastomotic stricture follows urinary diversion in 4% to 8% of patients and may lead to a progressive deterioration of renal function. There are problems with all current management techniques: surgical revision, endourologic incision, nephrostomy drainage, external ureteral stents, and dilation with a high-pressure angioplasty balloon. The authors present their long-term results with permanent ureteral Wallstents for the treatment of benign ureterointestinal stricture. PATIENTS AND METHODS: Eight patients with 10 strictures were treated by placement of self-expanding permanent indwelling stents via percutaneous nephrostomy between September 1993 and January 1998. The mean age of the group was 59.2 years. Development of strictures occurred a mean of 20.9 months after urinary diversion. There were seven complete and three partial strictures. Of 49 patients treated by the Camey procedure, 7 patients (14%) developed 9 (18%) strictures. Of 28 patients having the Wallace procedure, 1 patient (3.5%) developed one stricture. After recanalization of the distal ureter by a Terumo guidewire and dilation with a high-pressure angioplasty balloon, a Wallstent was placed across the stricture via a percutaneous approach. RESULTS: The endourologic placement of the Wallstent was well tolerated by all patients. The hospital stay averaged 2 days. Seven patients with nine strictures after the Camey procedure are doing well with a follow-up of 7 to 68 months (mean 22.4 months). One major complication was observed in one patient necessitating an additional procedure (lithotripsy) because of stone formation at the lower part of the stent extending into the neobladder in order to maintain patency after 68 months. The other patient, who had a Wallace procedure, is doing well 1 year 8 months afterward. CONCLUSION: An endourologic ureteral Wallstent approach to ureterointestinal stricture is a successful alternative, providing satisfactory management of the problem in most patients. No complication such as stent migration, hematuria, pain, or recurrent stricture was observed.

Aged↗

PubMed2001

Magnetic resonance imaging and histology of repair in femoral head osteonecrosis.

Different repair processes affect the clinical course of nontraumatic avascular femoral head osteonecrosis, not just necrotic lesion size and location. Fourteen femoral heads were retrieved at total hip arthroplasty after core decompression treatment, or after conservative treatment was done on 13 male patients diagnosed with different stages of femoral head osteonecrosis. To determine repair types, features of coronal magnetic resonance images were correlated with light microscopy findings on corresponding coronal undecalcified sections and microradiographs of the retrieved femoral heads. In five femoral heads, repair of necrotic bone and marrow remained restricted to the reactive interface for as many as 63 months, producing the diagnostic osteosclerotic rim with adjacent hypervascularity (limited repair). Nine femoral heads showed extension of the repair process into the necrosis. In five femoral heads, predominant resorption of necrotic bone led to femoral head breakdown within 2 to 50 months (destructive repair). In four femoral heads, reparative bone formation had started from subchondral fractures and/or the reactive interface, definitely reducing the size of the necrotic area (reconstructive repair). In the latter, the disease progressed slowly or stopped for as many as 45 months, irrespective of treatments, but elimination of risk factors seemed beneficial. Although core decompression did not always reach the necrotic area and improve repair, it reduced accompanying bone marrow edema and could delay the disease progress. Osteonecrosis with limited repair can be identified on magnetic resonance images obtained at followup, but the similar signal changes of destructive and reconstructive repair cannot be distinguished on magnetic resonance images alone. The evidence of reconstructive repair in nontraumatic osteonecrosis, however, gives hope for treatments that can improve repair to a sufficient creeping substitution of the affected femoral head.

Adult↗

PubMed2001

Gap junction-mediated bidirectional signaling between human fetal hippocampal neurons and astrocytes.

Gap junctions are clusters of intercellular channels that connect the interiors of coupled cells. In the brain, gap junctions function as electrotonic synapses between neurons and as pathways for the exchange of metabolites and second-messenger molecules between glial cells. Astrocytes, the most abundant glial cell type coupled by gap junctions, are intimately involved in the active control of neuronal activity including synaptic transmission and plasticity. Previous studies have suggested that astrocytic-neuronal signaling may involve gap junction-mediated intercellular connections; this issue remains unresolved. In this study, we demonstrate that second-trimester human fetal hippocampal neurons and astrocytes in culture are coupled by gap junctions bidirectionally; we show that human fetal neurons and astrocytes express both the same and different connexin subtypes. The formation of functional homotypic and heterotypic gap junction channels between neurons and astrocytes may add versatility to the signaling between these cell types during human hippocampal ontogeny; disruption of such signaling may contribute to CNS dysfunction during pregnancy.

Astrocytes↗

PubMed2001

Growth-suppressive function of human connexin32 in a conditional immortalized mouse hepatocyte cell line.

Mouse hepatocytes immortalized with a temperature-sensitive allele of the SV40 large T-antigen (CHST8 cells) were found to lack the high expression of the gap junction proteins Cx26 and Cx32 that characterizes normal mouse hepatocytes, expressing instead Cx43 and Cx45 at minimal levels. In order to examine the growth suppressive function of Cx32 on hepatocytes, we transfected these CHST8 cells with human Cx32 complementary deoxyribonucleic acid and measured the growth rates at 33, 37, and 39 degrees C. Expression of human Cx32 and its messenger ribonucleic acid in the stable cell lines was confirmed by immunocytochemistry and by Western and Northern blots analyses. Dye transfer following lucifer yellow injection into the transfectants was extensive; Cx32 channels displayed unitary conductances of about 70 pS and were moderately voltage sensitive. When cultured at 33 and 39 degrees C, growth rates of both parental cells and transfectants were of the same level. When examined at 37 degrees C, growth rate of the transfectant, which highly expressed Cx32 at the membranes, was significantly decreased compared to the parental cells. However, no changes in the expression of Cx32 protein in the transfectants were observed between 33 and 37 degrees C. These results suggest that Cx32 expression could inhibit hepatocyte growth in vitro using the conditional immortalized cells. Cx32 transfectants using a conditional immortalized mouse hepatocyte may be useful for examining the mechanisms of growth and differentiation in hepatocytes by gap junction expression.

Animals↗

PubMed2001

Prostate-specific antigen: current status.

PSA is the most important of all tumor markers because it has significant applications in all aspects of the management of men with prostatic disease. Certainly, the most important utilization of PSA is for early detection of this most ubiquitous of all human neoplasms. In this article the authors describe the molecular forms of PSA and their characteristics, the factors influencing values of serum concentration of PSA, the problems of screening, and particularly the possibility to use PSA for detection of prostate carcinoma. A big problem in prostate carcinoma detection is the low specificity of PSA at the concentrations between 4-10 ng/ml, the so-called diagnostic gray zone, where the incidence of prostate carcinoma is only 25%. The authors evaluate the methods which make it possible to increase the sensitivity and/or specificity of PSA detection, such as PSA density, PSA density of the transition zone, PSA velocity, PSA doubling time, age-specific PSA, free PSA and, prospectively, the use of the RT-PCR technique.

Biomarkers, Tumor↗

PubMed2001

Serum levels of cytokines in children and adolescents with Graves' disease and non-toxic nodular goiter.

It has been shown that human thyrocytes can synthesize cytokines which activate T and B lymphocytes. These immune cells play important roles in the initiation and continuation of thyroid autoimmunity. The aim of this study was to estimate serum concentrations of soluble interleukin-6 receptor (sIL-6R), interleukin-6 (IL-6) and interleukin-8 (IL-8) in patients with Graves' disease (GD) (n=44, mean age 14.8 years), in patients with nontoxic nodular goiter (NTNG) (n=36, mean age 15.6 years) and in a group of healthy controls (n=20, mean age 14.5 years). ELISA was used to determine the concentration of cytokines, antithyroglobulin and antithyroid peroxidase antibodies in patients with thyroid disease. Radio receptor assay (RRA) was performed to detect anti-TSH receptor autoantibodies (TRAb). Serum levels of IL-6, sIL-6R and IL-8 were markedly elevated in patients with GD before treatment with methimazole (p<0.0001 for IL-6, p<0.006 for sIL-6R, p<0.004 for IL-8) and after 8 weeks of therapy (p<0.011 for IL-6, p<0.04 for IL-8). However, following 24 months of treatment, normal serum concentrations of these cytokines were restored. Furthermore, patients with NTNG showed a slightly elevated concentration of cytokines (IL-6, IL-8). Serum levels of tri-iodothyronine in patients with GD positively correlated with serum concentrations of IL-6 (r = 0.35, p<0.025) and sIL-6R (r = 0.31, p<0.047), while no correlation was found between thyroxine and cytokines. Moreover, we observed a positive correlation between serum levels of TPO-Abs, TRAb and IL-6 (r = 0.43, p<0.008; r = 0.5, p<0.003) and between TPO-Abs and IL-8 (r = 0.67, p<0.0001). However, in patients with NTNG no correlation was observed between serum levels of antithyroid antibodies or thyroid hormones and serum levels of cytokines. We conclude that the cytokines (IL-6, sIL-6R, IL-8) could play an important role in the development of Graves' disease and that their levels are modulated by thyreostatic treatment.

Adolescent↗

PubMed2001

[Prophylactic use of counterpulsation in patients with severe myocardial dysfunction].

During the period between 2/2000 and 11/2000 21 patients with severe ventricular dysfunction were investigated (EF less than 30%) where in a planned manner intraaortic balloon counterpulsation was introduced before cardiac surgery. The low mortality (5%), zero incidence of complications caused by the method and the improvement of the contractility of the heart muscle, evaluated from a rise of the ejection fraction (EF) make so-called prophylactic use of contrapulsation possible as a method of first choice in severe myocardial dysfunction.

Aged↗

PubMed2001

[The influence of upright position on heart rate variability parameters in adolescents with hypertension and type 1 diabetes].

BACKGROUND: The autonomic regulation of heart rate variability (HRV) is impaired not only in patients with type 1 diabetes but either in nondiabetic hypertensive patients. AIM: The aim of the study was to evaluate the HRV parameters in adolescents with type 1 diabetes depending on appearance of hypertension. MATERIAL AND METHODS: The study group included of 34 patients with diabetes and hypertension aged 15+/-2.2, and 38 patients with diabetes without hypertension aged 15+/-2.9. The control group consisted of 55 healthy persons aged 15+/-2.2. In every examined person were performed tests of autonomic nervous system in accordance to Ewing battery and frequency-domain analysis of HRV during supine and standing position. RESULTS: The HRV parameters: total power (TP), low (LF) and high frequency (HF) were significantly decreased in patients with hypertension during supine and standing as compared to control group (p<0.001). There were differences between diabetics without hypertension and autonomic neuropathy and control group. The appearance of CAN in patients without hypertension caused the decrease all HRV indices during supine (p<0.001), however the standing position only decrease of TP and HF (p<0.01). TP value was depending on glycated haemoglobin concentration (p<0.001), but there was no correlation between HRV indices and left ventricular mass index. CONCLUSIONS: The decrease of HRV parameters in adolescents with diabetes type 1 is connected not only with autonomic neuropathy but also with appearance of arterial hypertension.

English Abstract↗

PubMed2001

[Precocious puberty: who should be treated?].

Authors, by a review in literature, show a therapeutical and diagnostic problems in diagnosis and treatment of the precocious puberty.

English Abstract↗

PubMed2001

[The epidemiology of type 1 diabetes in children and adolescents in north-east Poland in the period 1988-1999].

AIM: The studies performed in many European countries show the increasing tendency of the incidence of type 1 diabetes in different regions of our continent. The aim of study was the evaluation of incidence of type 1 diabetes in children and adolescents in north-east Poland in the period 1988-1999 and its analysis according to sex, age, place of residence and season of diabetes diagnosis. MATERIAL AND METHODS: Diabetic outpatient clinic and II Department of Pediatrics at Medical Academy in Białystok take medical care of children and adolescents in north-east macroregion of Poland (administrative border from 1975) with 4% population of Poland. Retrospective study was performed in the period 1.01.1988-31.12.1999. All new cases of diabetes in 0-18 years old children and adolescents were registered. Incidence index of IDDM was expressed by ratio of new diabetes cases to 100 000 age-selected population. The number of population was taken from Demographic Yearbooks 1988-1999 of Central Statistical Office. RESULTS: During twelve-year observation of developmental age population living in north-east Poland diagnosis of diabetes type 1 was established in 421 persons: 221 boys (52.5%) and 200 girls (47.5%). Incidence index for the whole region was 7.33 (4.6-10.1). The analysis of the patient age at the diagnosis revealed rarer occurrence of diabetes in children under 5 years - 53 persons (12.5%). The type 1 diabetes was more often recognized in pubertal period - 188 persons (44.65%). The highest increase in incidence of diabetes was noted in 5-14 years old persons and it reached 17/100,000 in 1999. The analysis of the place of residence showed the increase of diabetes incidence of only in country regions. It was the same in towns. The diabetes manifested itself more often in autumn and winter than in summer period. CONCLUSION: 1) The incidence of type 1 diabetes mellitus in north-east Poland rised significantly from 4.6 in 1988 to 10.1 in 1999. The identification of the etiological factors and prevention of disease may be necessary. 2) The seasonal incidence of type 1 diabetes confirms the real participation of environmental factors in etiopathogenesis of the disease.

English Abstract↗

PubMed2001

[Effectiveness of pre- and postprandial Humalog in adolescents with type 1 diabetes].

UNLABELLED: The aim of the study was to evaluate the glycaemic response to pre- and postprandial Humalog. MATERIAL: The study involved 47 type 1 diabetic adolescents between the ages 12 and 18 (mean 15.5) and the duration of diabetes from 1 to 13 years (mean 5.16). METHODS: All patients received Humalog in intensive therapy during 3-month period: 29 persons just before the meal and 18 immediately after the meal. All patients were injected with basal insulin twice a day (Humulin N). HbA1c values were determined at the beginning and the end of study. Patients' blood glucose levels were measured preprandially and 1 and 2 hours after eating their first bite of breakfast (noted in 1, 6 and 12 week of observation). At the end of observation (after 3 months) the analysis of the blood glucose levels after pre- and postprandial administration of Humalog insulin was performed. Blood samples were obtained at -40, -20, 0, 15, 60, 90, 120, 150 and 180 minute relative to the start of the meal. RESULTS: The mean HbA1c value decreased from 8.01 to 7.63%. The patients' preprandial glucose levels 1 and 2 hours after meal were similar in two groups in each measurement (1, 6, 12 week). The pre- and postprandial glucodynamics were similar in the two groups. The number of mild hypoglycaemic episodes was slightly higher in the group receiving Humalog before meal (0.32 vs. 0.19 episodes/person/day - p<0.05). CONCLUSION: Postprandial Humalog insulin may provide good postprandial glucodynamic control because it is safe, insulin dose can be matched to the actual food intake and it is not associated with an increase in the frequency of hypoglycaemic events. The possibility of the pre- and postprandial Humalog insulin administration improves the quality of life of patients with diabetes.

English Abstract↗

PubMed2000

Craniosynostosis in cherubism.

Cherubism is a rare autosomal dominant fibro-osseous disorder that affects almost exclusively maxilla and mandible. Extracranial skeletal involvement is rare. We report on three affected males in three generations. The youngest affected relative was examined at age 4 months. He also had craniosynostosis. His affected father and grandfather had cherubism and clubbing of the fingers. Cherubism was mapped to region 4p16. Because of the associated cranio-synostosis, we excluded the FGFR3 gene as a candidate gene for cherubism.

Adult↗

PubMed2000

[Diagnostic imaging in femur head necrosis].

Diagnosis of avascular necrosis (AVN) of the hip has been improved by the technical progress of imaging modalities during the last decade. For a long period, only plain radiographs had been available. Scintigraphy and computed tomography contributed to differential diagnosis and early detection of bone necrosis. In the meantime, MR imaging has gained special value in the evaluation of AVN. It is now the method of choice for early detection as well as for assessment in later stage disorders. Using the ARCO system, all imaging modalities and their diagnostic viability are described. Findings regarding the different stages of AVN are correlated to tissue-specific changes.

Diagnostic Imaging↗

PubMed2000

[Pathomorphological aspects and repair mechanisms of femur head necrosis].

The pathomorphologies of non-traumatic femoral head osteonecroses (ON) are usually similar, despite various known pathogenetic factors. The size and position of the subchondral bone and marrow segment, becoming necrotic after the ischemic event(s), and the kind of repair processes determine the time course and thus the fate of this hip joint disease. Four cases of conservatively or core decompression-treated femoral head ON were selected to demonstrate differently effective repair mechanisms which are discussed in respect to existing therapeutic concepts. Diagnostic criteria from magnetic resonance imaging follow-ups were correlated with light microscopy findings on undecalcified ground and microtome sections from femoral heads retrieved at total joint replacement. Initial stage (ARCO 0) and reversible early stage ON (ARCO 1) after incomplete ischemias can apparently show spontaneous sufficient repair. After extensive and complete ischemia, however, ON progresses without detectable changes on plain radiographs into irreversible early stage ON (ARCO stage 2). Only in exceptional cases (with small, medially located necroses), a spontaneous sufficient repair seems possible. Usually, early ARCO stage 2 ON with intact articular surface shows no remodeling of the subchondral necrotic bone and fatty marrow, but only ineffective repair with fibrovascular tissue invasion and bone resorption at the vital bone border. Repeated bone appositions on partly resorbed necrotic trabeculae form the sclerotic rim in this pathognomonic reactive interface. New bone formation can also be increased underneath the necrotic area and reactive interface when surrounded by accompanying bone marrow edema. Core decompression in ARCO stage 2 ON, even if it reaches the necrotic lesion, can at best delay progression of the disease, but never leads to complete reconstruction of the necrotic area. More likely, after both conservative and operative treatment, destructive resorption without effective consecutive bone formation will lead sooner or later to collapse of the articular surface and thus to mechanical instability of transition stage ON (ARCO stage 3). On the other hand, this subchondral fracture can apparently also cause reconstructive repair which, by involving chondral and membranous ossification in this "creeping substitution", can reduce the necrotic area. However, it cannot prevent progression into late stage ON (ARCO stage 4) with secondary joint destructions. Principally, besides the rare sufficient repair in initial and certain early ON, three forms of insufficient repair in the necrotic area can be distinguished: lack of remodeling, destructive remodeling, and reconstructive remodeling. To date, no therapeutical intervention exists which leads to complete healing of irreversible ON stages by reconstructive repair. Improved understanding of pathomorphology and repair mechanisms, however, could be the basis for future therapeutical concepts which should aim at the complete regeneration of the osteonecrotic area.

Adult↗

PubMed2000

["Transient osteoporosis" as a special reversible form of femur head necrosis].

There is still controversy whether transient osteoporosis of the hip joint represents a distinct self-limiting disease, or reflects only an early, reversible subtype of non-traumatic osteonecrosis (ON). Transient osteoporosis has several synonyms: algodystrophy of the hip; transient marrow oedema; or bone marrow oedema syndrome--BMOES. Clinical presentation of BMOES shows mechanical hip joint pain, ON risk factors, and a diffuse bone marrow oedema in MR imaging. Histomorphological changes resemble early ON, but with diffuse sufficient repair in BMOES and focal and insufficient repair only at the border of the necrotic lesion in ON. Therefore the clinical course and outcome are significant different, with restitution occurring in BMOES, while progressive destruction of the joint takes place in ON. So far, the preferred treatment strategies are protected weight bearing for BMOES, but operative treatment for ON. In a prospective study of patients with BMOES, the clinical, radiographic, and MRI course of 43 hip joints after core decompression treatment were investigated. All patients showed immediate relief of pain after surgery and the average duration of symptoms with conservative treatment could be dramatically reduced by core decompression from 6 months down to 2 months. There were no perioperative complications. Based on our experience with over 100 BMOES patients, we are convinced that this syndrome represents not a distinct disease but an early reversible subtype of non-traumatic ON. Due to the excellent clinical results of core decompression, we recommend this operative therapeutical concept in patients with painful BMOES.

Adult↗