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Biomedical subjects

M Urban

Publications and source records attributed to M Urban.

At least 73 records · Page 4Linked to original sources
PubMed1999

Increased acetylcholine-induced vasodilation in pregnant rats: A role for gap junctional communication.

We have tested the hypothesis that increased gap junctional communication contributes to the augmented endothelium-dependent vasodilation in pregnancy. Contractile force and connexin43 expression were measured in aortic rings from nonpregnant and pregnant rats. Norepinephrine-constricted aortas from pregnant rats were more sensitive to acetylcholine, but not to sodium nitroprusside, compared with those from nonpregnant rats. Vessels from pregnant rats, constricted either with 45 mmol/L KCl or with norepinephrine + 10(-4) mol/L N(G)-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthase, also exhibited greater relaxation to acetylcholine. Heptanol, an uncoupler of gap junctional communication, inhibited acetylcholine responses in norepinephrine-constricted aortas from nonpregnant rats but greatly impaired acetylcholine relaxation in aortas from pregnant rats. Heptanol also inhibited in both groups acetylcholine responses in vessels constricted with KCl, only minimally affected acetylcholine relaxation in arteries constricted with norepinephrine + L-NMMA, and did not change sodium nitroprusside-induced relaxation. Tetraethylammonium chloride induced greater contractions in control aortas compared with aortas from pregnant rats. Increased connexin43 mRNA levels were found in the uterus and in the mesenteric, uterine, and thoracic aortic arteries, but not in the heart and brain, from pregnant rats. These results suggest that increased gap junctional communication, possibly due to increased gap junction protein expression, may facilitate the effects of endothelium-derived relaxing factors, contributing to the augmented endothelium-dependent relaxation in arteries from pregnant rats.

Acetylcholine↗
PubMed1999

TPA induced expression and function of human connexin 26 by post-translational mechanisms in stably transfected neuroblastoma cells.

Connexin 26 (Cx26) has been proposed to be a tumor suppressor gene and its expression may modulate development, cell growth and differentiation in various tissues, including the brain. 12-O-tetradecanoylphorbol-13-acetate (TPA) may serve as either tumor promoter (in mammary gland amd skin) or as a differentiating agent (in neuroblastoma and leukemic cells) and may also modulate expression, function and phosphorylation of gap junctions. In this study, to determine the effects of TPA on Cx26 expression and its function in neuroblastoma, we transfected N2A mouse neuroblastoma cells (which are gap junction deficient) with the coding region of human Cx26 gene (which lacks TPA response elements) and examined the changes of expression and function of Cx26 following 10 nM TPA treatment. Individual clones of transfectants stably expressed distinct levels of exogenous Cx26 as judged by Northern and Western blots, immunocytochemistry and electrophysiological recordings. Cx26 channels displayed unitary conductances of about 140-155 pS. Increase of Cx26 expression following TPA treatment was markedly observed using immunocytochemistry and Western blots of membrane fractions although it was not detected in Northern or Western blots of whole cells. This increase in Cx26 expression in the plasma membrane was accompanied by an increase of function as evidenced in measurements of junctional conductance. These results suggest that induction of exogenous Cx26 in neuroblastoma cells by TPA treatment is controlled by post-translational mechanisms.

Animals↗
PubMed1999

A simple RT-PCR-based strategy for screening connexin identity.

Vertebrate gap junctions are aggregates of transmembrane channels which are composed of connexin (Cx) proteins encoded by at least fourteen distinct genes in mammals. Since the same Cx type can be expressed in different tissues and more than one Cx type can be expressed by the same cell, the thorough identification of which connexin is in which cell type and how connexin expression changes after experimental manipulation has become quite laborious. Here we describe an efficient, rapid and simple method by which connexin type(s) can be identified in mammalian tissue and cultured cells using endonuclease cleavage of RT-PCR products generated from "multi primers" (sense primer, degenerate oligonucleotide corresponding to a region of the first extracellular domain; antisense primer, degenerate oligonucleotide complementary to the second extracellular domain) that amplify the cytoplasmic loop regions of all known connexins except Cx36. In addition, we provide sequence information on RT-PCR primers used in our laboratory to screen individual connexins and predictions of extension of the "multi primer" method to several human connexins.

Animals↗
PubMed1999

MR arthrography of the adult acetabular capsular-labral complex: correlation with surgery and anatomy.

OBJECTIVE: Our purpose was to describe the appearance of the acetabular capsular-labral complex on MR arthrography and to correlate this appearance with surgical findings in adult patients and with gross anatomic findings in cadavers. SUBJECTS AND METHODS: MR arthrography of the hip joint was performed in 40 patients and six cadavers. All patients underwent subsequent arthrotomy of the hip. MR arthrography consisted of a T1-weighted three-dimensional gradient-echo sequence in both the coronal oblique and sagittal oblique planes after intraarticular injection of a 2 mmol/l solution of gadopentetate dimeglumine. The normal and pathologic appearance of the capsular-labral complex was assessed, and the labra were evaluated on the basis of morphology, signal intensity, presence of a tear, and attachment to the acetabulum. MR arthrography findings were correlated with the surgical results in all patients and with the anatomic sections of the cadaveric hip joint specimens. RESULTS: MR arthrography images of the T-weighted three-dimensional gradient-echo sequences allowed visualization of the anatomic structures. The normal labrum was triangular, without any sublabral sulcus, and of homogeneous low signal intensity. A recess between the labrum and the joint capsule could be identified in instances in which no thickened labrum was present. Labral lesions included labral degeneration, a tear, or a detached labrum either with or without thickening of the labrum. The sensitivity for detection and correct staging of labral lesions with MR arthrography in the patient study was 91%; the specificity, 71%; and the accuracy, 88%. CONCLUSION: MR arthrography with T1-weighted three-dimensional gradient-echo sequences allows excellent assessment of the normal and pathologic acetabular capsular-labral complex.

Acetabulum↗
PubMed1999

[The evaluation of contrast sensitivity in children and adolescents with insulin-dependent diabetes mellitus].

PURPOSE: The evaluation of contrast sensitivity in children and adolescents with type I diabetes mellitus with and without retinopathy, taking into account metabolic control. MATERIAL AND METHODS: We examined 100 young patients (71 without retinopathy and 29 with background retinopathy on fluorescein angiography) and 60 control non-diabetic subjects matched for age and sex, without visual or systemic symptoms. Contrast sensitivity was measured in spatial frequency of 3, 6, 12 and 18 cycles/degree (c/d). RESULTS: Contrast sensitivity was significantly lower (p < 0.001) in four spatial frequencies in all diabetic patients and in IDDM patients without retinopathy than in control group. Patients with IDDM and retinopathy had abnormal contrast sensitivity at spatial frequency 18 c/d when compared with patients without retinopathy. There was no correlation between contrast sensitivity and HbA1c values. CONCLUSIONS: Contrast sensitivity measurement in children and adolescents with type I diabetes is useful in the evaluation of the nature of early abnormalities in retinal function of diabetics.

Adolescent↗
PubMed1999

[Emergency myocardial revascularization during a developing myocardial infarct].

In 1996-1998 in our Cardiocentre urgent revascularizations were made in 28 patients with developing acute myocardial infarction (AIM) with manifestations of different grades of acute circulatory failure up to developed cardiogenic shock and cardiac arrest. In all patients complete revascularization with a mean number of 2.9 bypasses per patient was made, in one patient at the same time a rupture of the interventricular septum was closed and in two patients an insufficient mitral valve was replaced. From the whole group two patients died during the early postoperative period, two were revised on account of postoperative haemorrhage and two had signs of low cardiac output. Twenty-two patients had a postoperative course without complications. Urgent surgical revascularization in patients developing AIM and circulatory deterioration is the method of primary and definite treatment when primary PTCA is not suitable.

Adult↗
PubMed1999

Ellis-van Creveld syndrome: examination at 15 weeks' gestation.

In 1940, Ellis and van Creveld defined a syndrome they referred to as chondro-ectodermal dysplasia. This autosomal recessive condition, now usually referred to as Ellis-van Creveld syndrome (EVC), comprises bilateral postaxial polydactyly, a chondrodysplasia, characterized by shortness of limbs, and ectodermal dysplasia. Congenital heart defects are also common. There are many reports in medical literature describing affected newborns and even, older children. Here, we report the clinical, radiological and histological findings in a 15-week-old affected fetus. The diagnosis of Ellis-van Creveld syndrome in this fetus is based on a positive family history (an affected sib) and shortness of long bones as well as hexadactyly diagnosed by prenatal ultrasonography. On post-mortem examination, bilateral postaxial hexadactyly and symmetrical shortness of the long bones was noted. Histologically, there was too short a zone of cartilagineous columns in the metaphyses, a reduced number of chondrocytes and an irregularly structured spongiosa within the ossification zone. In addition, the fetus was found to have an atrio-ventricular canal. This heart defect is presumably rare in this syndrome. Other characteristic features such as small and dysplastic nails, sparse hair and abnormalities of the teeth were, of course, not yet present in this early developmental stage. In addition to EVC, the fetus had a 47,XXY chromosome constitution.

Adult↗
PubMed1999

[Fluorescein angiography in children and adolescents with type I diabetes mellitus].

PURPOSE: The evaluation of changes in ophthalmoscopic examination and fluorescein angiography in children and adolescents with insulin dependent diabetes mellitus. MATERIAL AND METHODS: 100 patients with type I diabetes mellitus aged 9.3-21.5 years (15.76 +/- 2.69), with diabetes duration of 1-13.5 years (6.57 +/- 2.52) were examined. RESULTS: Retinal changes in ophthalmoscopic examination were observed in 12 cases. Fluorescein angiography allowed to detect diabetic retinopathy in 29 patients. There was no correlation between the incidence of retinopathy and the age of patients. Vascular abnormalities were related to the duration of diabetes. Retinopathy was not found in children < 10 years of age.

Adolescent↗
PubMed1999

[Epidemiology of diabetes type 1 in the 0 to 29 year-old age group in Northeastern Poland, 1994-1998--prospective observations].

It was recently suggested that there is a tendency of the rising incidence of diabetes type 1 in different countries in Europe. In our previous studies we observed the high frequency of ICA among first degree relatives of diabetic subjects, what could suggest a rapid increase in the incidence of diabetes type 1 also in the north-eastern region of Polan. The aim of the study was to estimate the annual incidence of diabetes type 1 in the north-eastern region of Poland and to evaluate the association of the incidence rates with the age, gender, urban-rural differences and the season of the year of the disease onset. The register of new cases of IDDM was established in 1994 using 2 independent data sources. The degree of ascertainment was 98.9% for the combination of both data sources. We observed a rising trend in the incidence from 6.4 in 1994 to 9.9 cases per year per 100,000 in 1998 (p < 0.001). The highest incidence rate increase was recorded in boys aged 5 to 14 years old (16-17 cases per 100,000 in 1997-1998). The rising trend in this incidence was observed in the rural areas, while in urban populations the incidence was unchanged. Seasonal variation in the incidence was also recorded, with a peak in autumn and winter and nadir in summer. Our observations suggest the necessity of the continuation of the studies to identify the diabetogenic environmental factors and to try preventive procedures in the studied population.

Adolescent↗
PubMed1999

[Serum levels of interleukin 6 (IL-6) and soluble IL-6 receptor (sIL-6R) in children and adolescents with Graves-Basedow disease].

The concentration of interleukin 6 (IL-6), soluble IL-6 receptor (sIL-6R) and intercellular adhesion molecule-1 (sICAM-1) was assayed in 24 children with Graves' disease, aged 6.5-17 years, before treatment with methimazole, during clinical and biochemical remission (8 weeks), and following the eighteen-month therapy with the thyrostatic. ELISA method was used to determine the concentration of interleukin 6, sIL-6R and sICAM-1. An increase was observed in serum concentration of IL-6 and its receptor sIL-6R and soluble intercellular adhesion molecule-1 in the course of Graves' disease. A significant reduction in sIL-6R (8 weeks) and IL-6 (18 months) was noted after therapy with methimazole. A positive correlation was found between microsomal antibodies and the concentration of sICAM-1 and sIL-6R, and between antithyroglobulin antibodies and concentration of sIL-6R in children with fresh hyperthyroidism. No correlation was revealed between the level of thyroid hormones and the concentration of cytokines and adhesion molecules.

English Abstract↗
PubMed1999

[Usefulness of antioxidant vitamin supplementation in children and adolescents with newly diagnosed diabetes mellitus type I].

BACKGROUND: Diabetes type I is caused by immune-mediated destruction of the b-cells. During the immune response macrophages release free oxygen radicals and cytokines which damage DNA. Ascorbic acid, b-carotene, a-tocopherol and nicotinamide act as antioxidants (free radical scavengers). OBJECTIVES: Comparative analysis of diabetes mellitus clinical course in the first year after diagnosis with and without antioxidative vitamin supplementation. MATERIAL AND METHODS: 40 children and adolescents with newly-diagnosed diabetes type I treated with: group A (n=13) n insulin + diet, group B (n=14) n additional vitamins A+E, C, group C (n=13) n additional vitamins A+E, C, PP. RESULTS: The remission was observed in n=13 (92.8%) children in group B, in n=6 (46.1%) in group C and only in 2 (15.4%) in group A after 3-4 months. After 6-7 months the remission was obtained in 10 patients (71.5%) in group B, in 6 (46.1%) - in group C and in 4 (30.8%) - in group A. After one year observation 6 (42.5%) patients in group B had remission, 4 (30.7%) in group C and 2 (15.4%) - in group A. Daily insulin demand was similar after diagnosis, after 3-4 months it was more reduced in group B (x - 0.28 u./kg/d, SD n 0.23) vs. x - 0.40 u./kg/d SD n 0.24 (group C) and vs., x - 0.5 u./kg/d - (group A). The insulin demand was augmented in the following months but all the time it was lower in the group supplemented by vitamins A, E, C. The glycaemic control and the values of lipids, thiobarbituric and reactive substances, group-SH of glutathione and vitamin C were similar in analysed groups in simultaneous periods. CONCLUSIONS: Supplementation with antioxidant vitamins in newly diagnosed diabetes mellitus type I leads to more frequent remissions and reduced insulin demand, particularly in the first months of diabetes duration.

English Abstract↗
PubMed1999

[The prevalence of autoimmunological diseases in families of children with type I diabetes].

BACKGROUND: type I diabetes mellitus is considered as an autoimmune disease and is often associated with other diseases of that etiology. The genetic susceptibility to autoimmune disorders causes type I diabetes to occur more frequently in relatives of the diabetic patients. OBJECTIVE: To evaluate the prevalence of type I diabetes and other autoimmune diseases in families of the children with type I diabetes. MATERIAL AND METHODS: The prevalence of type I diabetes mellitus and other autoimmune endocrinopathies was evaluated in I, II and III degree relatives of 155 children with type I diabetes mellitus and 90 control children. RESULTS: It was observed that: 1) diabetes mellitus occurred more often in relatives of diabetic children (in 22 families - 14.2%) in comparison with the control group (in 2 families - 2.2%); 2) other autoimmune diseases occurred frequently in families of diabetic children and they affected 2 or more members of one family more often than in the control group (18 families vs 4); 3) rheumatoid arthritis occurred more frequently in families of diabetic children. CONCLUSIONS: The familial prevalence of type I diabetes mellitus and the tendency to more frequent prevalence of other autoimmune diseases in families of diabetic children was confirmed.

English Abstract↗
PubMed1999

[Pseudohypoparathyroidism in a 14-year old girl].

The authors describe the case of a 14-year old girl with pseudohypoparathyroidism, who showed characteristic phenotypic features of Albright's hereditary osteodystrophy (short stature, round face, mild obesity, abnormal position of teeth, lack of canines, limb valgity) and biochemical disturbances--hypocalcemia, hyperphosphatemia. The nature of pseudohypoparathyroidism consists in a lack of response to the parathormone of effector organs, such as kidneys, bones, alimentary tract. The treatment of choice includes active metabolites of vitamin D3, calcium salts, phosphate-binding components. Pseudohypoparathyroidism is a rare disease. Worth noting is the fact that it can occur in a child with height deficiency.

English Abstract↗
PubMed1998

Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome.

We report on a 13-year-old patient followed since birth. He is the only offspring of young, non-consanguineous German parents. His mother has an isolated left cleft of lip and a cleft palate. At birth, our patient presented with bilaterally cleft lip/cleft palate, phocomelia of upper limbs with normal hands, and mild symmetrical deficiencies of the long bones of the lower limbs. Haematological evaluation demonstrated a leukaemoid reaction during a urinary tract infection as well as intermittent thrombocytopenia and episodes of marked eosinophilia during the first two years of life. Intellectual development has been normal. Comparison with two similar cases from the literature suggests a non-random phenotypic overlap of Roberts syndrome (MIM 268300) and TAR syndrome (MIM 274000). Such clinical constellations may be key observations to understand the genetic relationship of Roberts syndrome and TAR syndrome in future phenotype-genotype correlations.

Adolescent↗
PubMed1998

Alice Vance ("Das Bärenweib"): a historical case of Nievergelt syndrome.

Several malformed individuals were presented at the World Exhibition in Antwerp in 1894. Among them was Mrs. Alice Vance from Mount Pleasant, Texas, with congenital limb defects, and Mr. Eugen Berry, who had asymmetrical, monstrous enlargement and macrodactyly of the feet, i.e., Proteus syndrome. After the World Exhibition Mrs. Vance presented herself to the public in Castan's Panopticon imitating a bear. She became famous under the stage name "Das Bärenweib" ("the bear-like woman") and was examined by several German clinicians, and her malformations were considered to be of high scientific interest. Mrs. Vance had mesomelic dwarfism and her mother was known to have similar malformations. Her limb deficiencies were generally considered a unique congenital condition those days, and the diagnosis of "a maternally inherited malformation of the forearms and the shanks" [Daffner 1898: Munch Med Wochenschr 25:782] was made. Virchow [1897: Verh Berl Ges Ethnol Urgeschichte 29:624], feeling attacked by a daily newspaper stating that the physicians as well as the police of Berlin had missed the diagnosis of an "English disease," eventually exercised his authority and diagnosed Alice Vance as a "phocomelic." Clearly, she was not a phocomelic according to past and current definition of this term. Thus, from a historical point of view, the story illustrates how pressure from the daily press altered the definition of an up-to-then precisely defined medical term for decades. According to the clinical data and an X-ray report available from the literature, Alice Vance had a dominantly inherited type of mesomelic dwarfism. We propose the diagnosis of Nievergelt syndrome.

Abnormalities, Multiple↗