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Biomedical subjects

H Urich

Publications and source records attributed to H Urich.

At least 19 recordsLinked to original sources
PubMed1999

alpha-Lipoic acid decreases oxidative stress even in diabetic patients with poor glycemic control and albuminuria.

In the present cross-sectional study, the influence of alpha-lipoic acid on markers of oxidative stress, assessed by measurement of plasma lipid hydroperoxides (ROOHs), and on the balance between oxidative stress and antioxidant defence, determined by the ratio ROOH/(alpha-tocopherol/cholesterol), was examined in 107 patients with diabetes mellitus. Patients receiving alpha-lipoic acid (600 mg/day for > 3 months) had significant lower ROOHs and a lower ROOH/(alpha-tocopherol/cholesterol) ratio than those without alpha-lipoic acid treatment [ROOH: 4.76 +/- 2.49 vs. 7.16 +/- 3.22 mumol/l; p < .0001] and [ROOH/(alpha-tocopherol/cholesterol): 1.37 +/- 0.72 vs. 2.16 +/- 1.17; p < 0.0001]. In addition, the influence of glycemic control and albuminuria on ROOHs and on the ratio of ROOH/(alpha-tocopherol/cholesterol) was examined in the presence and absence of alpha-lipoic acid treatment. Patients were subdivided into three groups based on (1) their HbA1 levels (< 7.5, 7.5-9.5, and > 9.5%) and (2) their urinary albumin concentrations (< 20, 20-200, and > 200 mg/l). Neither poor glycemic control, nor the presence of micro- or macroalbuminuria prevented the antioxidant effect of alpha-lipoic acid. Using stepwise multiple regression analysis, alpha-lipoic acid was found to be the only factor significantly predicting low ROOHs and a low ratio of ROOH/(alpha-tocopherol/cholesterol). These data provide evidence that treatment with alpha-lipoic acid improves significantly the imbalance between increased oxidative stress and depleted antioxidant defence even in patients with poor glycemic control and albuminuria.

Albuminuria↗
PubMed1995

Calbindin-D28k in subsets of medulloblastomas and in the human medulloblastoma cell line D283 Med.

OBJECTIVE: To evaluate the antigenic expression of calbindin-D28k in surgically resected cerebellar medulloblastomas and the human medulloblastoma cell line D283 Med in relation to glial neoplasms, the human glioblastoma (U-251 MG) and rat glioma (C-6) cell lines, and other primary and metastatic brain tumors. DESIGN: Immunohistochemical staining was performed using an antiserum and a monoclonal antibody against calbindin-D28k on (1) formalin-fixed, paraffin-embedded human, predominantly posterior fossa, brain tumor specimens (49 medulloblastomas, 59 glial and mesenchymal primary central nervous system tumors, 1 posterior fossa rhabdoid tumor, and 34 metastatic tumors); (2) formalin-70% alcohol-, or Bouin's-fixed tumor cell lines (D283 Med, U-251 MG, and C-6) maintained in a three-dimensional gelatin foam (Gelfoam matrix) system, with or without treatment with dibutyryl cyclic adenosine monophosphate; and (3) formalin-fixed, paraffin-embedded C-6 glioma cells transplanted intracerebrally to rats. RESULTS: Calbindin-D28k immunohistochemical staining was detected in 20 of 49 cerebellar medulloblastomas and in cells of the human medulloblastoma cell line D283 Med grown in gelatin Gelfoam matrices, with or without treatment with dibutyryl cyclic adenosine monophosphate. In surgical resection specimens, calbindin-D28k reactivity was evident in populations of poorly differentiated cells of classic (non-nodular) medulloblastomas (16/20) and in mature Purkinje neuronlike phenotypes in medulloblastomas with ganglion cells (4/6) but was absent in desmoplastic medulloblastomas, including in areas of neoplastic neuritogenesis ("pale islands") (0/23). Calbindin-D28k staining was also present in D283 Med explants for up to 29 days in vitro. Reactivity was more widespread in dibutyryl cyclic adenosine monophosphate-treated cultures, coinciding with neuronal morphologic alterations of cultured cells. Focal calbindin-D28k stainig was present in neural-like cells of an embryonal cerebellar tumor with divergent mesenchymal, epithelial, and neuroectodermal/neuroendocrine differentiation suggestive of a malignant rhabdoid tumor. No calbindin-D28k staining was obtained in primary glial and mesenchymal (intra- and extra-axial) brain tumors (0/59), in explants of human glioblastoma cell line U-251 MG, or in the rat glioma line C-6 maintained in Gelfoam matrices or transplanted intracerebrally. Among 34 epithelial and mesenchymal tumors metastatic to the posterior fossa, only subpopulations of cells in two small-cell (neuroendocrine) carcinomas originating in the lung were calbindin positive. CONCLUSION: Calbindin-D28k expression in classic medulloblastomas, medulloblastomas with ganglion cells, and in the human medulloblastoma cell line D283 Med (which was derived from a metastatic classic medulloblastoma) suggests a phenotypic kinship between subsets of this tumor and neuronal progeny of the ventricular neuroepithelium, thus conferring additional support for its neuroblastic nature.

Animals↗
PubMed1993

Symmetrical neurofibroma with Schwann cell predominance and focal formation of microneurinomas.

A case of symmetrical neurofibroma with onion bulbs in various stages of development and progression to microneurinomas is presented. Immunohistochemistry with differentiation and growth factor markers as well as electron microscopy showed a Schwann cell origin of the concentrically arranged cells. The onion bulbs differed from those of hypertrophic neuropathy by their more compact structure. A partial expression of cellular proliferation markers in the onion bulbs was consistent with a multifocal proliferative activity, confirming the neoplastic nature of the lesion.

Adult↗
PubMed1993

Differential localization of class III, beta-tubulin isotype and calbindin-D28k defines distinct neuronal types in the developing human cerebellar cortex.

This immunohistochemical study compares the localization of the neuronal class III beta-tubulin isotype (beta III) to that of calbindin-D28k in 40 human fetal and postnatal cerebella ranging from 12 weeks gestation to adulthood. In the external granule layer of the developing cerebellar cortex, beta III staining was present in the premigratory (postmitotic) zone of horizontal neurons but was absent in "epithelioid" cells of the subpial proliferative mitotic zone. In the molecular layer, intense beta III staining was associated with parallel fibers, stellate/basket neurons and migrating fusiform granule neurons. beta III staining was also present in internal granule neurons. In contrast, beta III was not detectable in fetal and neonatal Purkinje neurons and Golgi II neurons, but was evident in these neurons from juvenile and adult cerebella. Calbindin-D28k staining was present in Purkinje neurons also delineating their somatic spines ("pseudopodia"), lateralizing and apical dendrites (including dendritic spines), subpopulations of small to intermediate-sized Golgi II neurons in the internal granule layer ("synarmotic cells" of Landau), large to medium-sized subcortical Golgi II neurons and neurons of cerebellar roof nuclei, at various gestational stages and postnatally. It was absent in the external granule layer, parallel fibers, stellate/basket and internal granule neurons. Variable degrees of beta III and calbindin-D28k staining were detected in subpopulations of immature neuroepithelial cells of the ventricular matrix at the roof of the fourth ventricle. Glial (including Bergmann glia) and mesenchymal cells were not stained for either antigenic determinants. The differential expression of calbindin-D28k and beta III defines distinct populations of neurons in the developing human cerebellar cortex and supports the ontogenetic concept of Ramon y Cajal.

Adolescent↗
PubMed1992

Gliofibroma: immunohistochemical analysis.

A case of gliofibroma occurring in an adult patient as a large circumscribed supratentorial tumor is reported. The bimorphic pattern was substantiated and further analyzed by immunohistochemistry. Some evidence in favor of collagen production by mesenchymal and/or inflammatory cells leading to a progressive fibrous replacement of the glial cells in this particular tumor type is presented.

Adolescent↗
PubMed1992

Vascular permeability changes in tumours of the peripheral nervous system.

Vascular permeability changes were examined in 34 tumours of the peripheral nervous system by immunohistochemical demonstration of serum proteins as endogenous tracers. The blood-tumour barrier was impaired in the reticular (Antoni type B) portions of neurinomas (Schwannomas) and in cutaneous neurofibromas but was similar to the normal blood-nerve barrier in fibrillary (Antoni type A) neurinomas, in most neurofibromas, in ganglioneuromas and in anaplastic tumours. These differences in permeability are discussed in relation to aspects of pathological tumour vascularization, the histogenesis of microcystic changes, and systemic therapeutic approaches.

Adult↗
PubMed1991

Basic fibroblast growth factor and somatomedin C in human medulloepithelioma.

Two published cases of medulloepithelioma, a rare malignant pediatric brain tumor composed of a mixture of primitive neuroepithelium and its differentiated neuronal and glial descendants, were examined by immunohistochemical staining for the presence of growth factors. From a panel of antibodies, those identifying basic fibroblast growth factor and insulin-like growth factor I, formerly known as somatomedin C, were strongly immunoreactive within the neuroepithelial cell population of the tumors. Immunoblots of purified recombinant basic fibroblast growth factor and insulin-like growth factor I showed antibody specificity without cross-reactivity. In controls, immunostaining of tissue sections was abolished by preabsorption of primary antibodies with the appropriate growth factor polypeptide antigen. Preabsorption with inappropriate growth factor did not reduce the intensity or alter the distribution of staining. The congruent histologic patterns of immunoreactivities suggest that more than one type of growth factor may be produced by the neuroepithelial component of medulloepithelioma. These growth factors may stimulate proliferation and differentiation of tumor cells by autocrine molecular mechanisms.

Animals↗
PubMed1990

The brain in the 18q-syndrome.

The authors describe the cerebral neuropathological findings of a 25 1/2-year-old male with 18q-syndrome. An abnormal gyral pattern, atrophy of the olfactory and optic nerves and small neocerebellar hemispheres with hemispheral lobular sclerosis were noted. Microscopically there were pial glioneuronal heterotopias; misplacement of neurons in the molecular layer of the cortex, as well as in deep white matter; not readily identifiable Betz cells; gliosis of olfactory and optic tracts and elsewhere; and loss of Purkinje cells. Further detailed studies of other cases are needed to determine whether these abnormalities are characteristic of the 18q-syndrome.

Adult↗
PubMed1989

Hemimegalencephaly, hemifacial hypertrophy and intracranial lipoma: a variant of neurofibromatosis.

A case is presented of a 30-year-old, mentally retarded and epileptic patient, with a progressive hemifacial hypertrophy since birth. Repeated biopsies revealed the neurofibromatous nature of her facial lesion. Autopsy also revealed an ipsilateral hemimegalencephaly, as well as meningeal lipomas and osteomas. This combination of lesions represents an unusual variant within the spectrum of neurofibromatosis.

Adult↗
PubMed1989

Focal neuronal gigantism and cerebral cortical thickening after therapeutic irradiation of the central nervous system.

An exceptional type of cortical dysplasia is described in the brain of a 32-year-old woman who had received radiation therapy for a large pituitary adenoma 6 years before death. Markedly thickened gyri of the left inferior frontal, insular, and temporal cortex were found grossly. Microscopically, these gyri showed laminar disorganization and many unusually large and abnormally shaped ganglion cells. These neurons were heavily impregnated with silver preparations; were strongly reactive for neuron-specific enolase, synaptophysin, and neuronal cytoskeletal proteins (68- and 200-kd subunits of neurofilament protein, microtubule-associated protein 2, and tau); and ultrastructurally contained numerous perikaryal neurofilaments. Collectively, these findings suggest that the abnormally large, misshapen neurons contained excessive accumulations of cytoskeletal intermediate filaments. The present case and a similar one described in 1964 are the only two documented instances of neuronal gigantism apparently related to therapeutic irradiation of the brain.

Adenoma↗
PubMed1988

Epidermal growth factor receptor in meningiomas is expressed predominantly on endothelial cells.

The immunohistochemistry of the epidermal growth factor receptor (EGFR) was studied with monoclonal antibodies in 12 meningiomas of various histologic subtypes, nine benign and three malignant. Strong immunoreactivity of EGFR epitopes was found in the endothelia of the tumor vasculature in six cases. A much weaker reaction was detected within tumor cells in six cases, in one of which it was diffuse and five focal. No correlation was established between the presence of EGFR epitopes and the histologic type or biologic behavior of the meningiomas. The results suggest that the EGFR may participate in tumor angiogenesis, but its role in the growth of neoplastic meningioma cells remains elusive.

Endothelium, Vascular↗
PubMed1988

Lhermitte-Duclos disease. An immunohistochemical study of the cerebellar cortex.

Immunocytochemical studies were carried out on two previously reported autopsy cases of Lhermitte-Duclos disease. The unaffected cerebellar cortex adjacent to the lesions served as control. The findings supported the view, previously expressed by one of the authors, of a heterogeneous neuronal structure of the lesion, consisting of at least two cell types. No further light was thrown on the predominant medium-sized cells, believed to represent hypertrophic internal granular neurons. On the other hand the large cells shared a number of features with Purkinje cells. In particular they were recognized by the pan-T-cell antibody anti-Leu-4, were surrounded by axosomatic synapses visualized by the antisynaptic vesicle glycoprotein antibody SV2, and contained both non-phosphorylated and phosphorylated neurofilament epitopes. It is suggested that these cells represent dysplastic Purkinje cells. The lesion therefore appears to be a complex hamartoma rather than a simple hypertrophy of the internal granular neurons.

Antibodies, Monoclonal↗
PubMed1988

Ectopic midline spinal ganglion in diastematomyelia: a study of its connections.

The connections of an ectopic midline spinal ganglion associated with an asymptomatic sacral diastematomyelia were studied. The ganglion was intercalated in the ventral root of one hemicord and sent its efferents to the dorsal root of the other hemicord. The afferents joined the anterior root to form a midline intradural spinal nerve in the cauda equina. Islands of ectopic glia were present in both roots and the spinal nerve. Both the midline position of the ganglion and the glial heterotopias can be tentatively explained by the failure of incorporation of the dorsal cell wedge ("Zwischenstrang") into the divided neural tube.

Choristoma↗
PubMed1987

The cytoskeleton of the human cerebellar cortex: an immunohistochemical study of normal and pathological material.

Monoclonal antibodies to non-phosphorylated and phosphorylated neurofilaments, as well as monoclonal and polyclonal antibodies to other cytoskeletal elements, were applied to the study of the cerebellar cortex of normal and pathological human material. The methods proved to be applicable to formalin fixed paraffin embedded tissue, provided the period of formalin fixation was short. The main difference between normal and pathological material was found in Purkinje cells and their dendrites. While normal Purkinje perikarya and dendrites expressed only non-phosphorylated neurofilaments, reactive dendrites stained more intensely with antibodies to phosphorylated neurofilaments. Similar observations were made on the abnormal dendritic ramifications of the partially deafferented, hypertrophic, inferior olive. The significance of the appearance of phosphorylated neurofilament epitopes in abnormal dendrites remains unknown and requires further investigation.

Adult↗
PubMed1987

Involvement of choroid plexuses in neurosarcoidosis.

A 43-year-old woman, known to have suffered from chronic multisystem sarcoidosis since the age of 28, developed a posterior fossa mass and obstructive hydrocephalus 2 years before death. At autopsy she was found to have hydrocephalus involving all four ventricles, mass lesions in the brain stem and cerebellum, and severe involvement of the choroid plexuses. The optic nerves and chiasm were also infiltrated with granulomas. Only minimal lesions were found in other parts of the brain.

Adult↗
PubMed1987

Arhinencephaly. The spectrum of associated malformations.

Eight cases are presented of arhinencephaly and its associated malformations, which included 2 examples of holoprosencephaly and 3 of agenesis of the corpus callosum. Additional features included cortical malformations, anomalies of the long tracts and of the optic pathway, cerebellar hypoplasia and dentato-olivary dysplasia. Each of these components covered a wide spectrum ranging in severity from extreme to minimal. Craniofacial dysmorphism, and cardiac, renal and endocrine disorders were present in some cases. Only 2 cases were associated with chromosomal abnormalities, 1 with trisomy 13, the other with partial trisomy 7(7q+). Of possible environmental factors, maternal diabetes was recorded in 1 case. While all cases can be classified into broad categories, the individual variations render each case apparently unique.

Abnormalities, Multiple↗
PubMed1987

The brain in partial trisomy 18: a case report.

This is a clinical and neuropathological report of a 27-year-old male with partial trisomy of the long arm of chromosome 18. Severe psychomotor retardation, blindness, and epilepsy were the major clinical features. Microcephaly, an unusual diverticulum of the left occipital lobe, and severe atrophy of the visual system were the major findings on neuropathological examination.

Adult↗