Biomedical subjects
S Nemecek
Publications and source records attributed to S Nemecek.
The 1998 Nobel Prizes in Science.
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Unequal health.
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When good health is good business.
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Cerebral angiogenesis shows nestin expression in endothelial cells.
The class VI intermediate filament protein nestin has been generally considered as a specific marker for neural precursor cells or developing muscles. In the prenatal developing rat central nervous system (CNS), we localized immunoreactivity for the nestin in blood vessels. Although the widespread nestin expression in cerebral blood vessels persisted in early postnatal periods, it was down-regulated in the adulthood. However, when the adult rat brains were subjected to procedures that trigger neovascularization, e.g. grafting fetal nervous tissue or C6 glioma, the abundant immunoreactivity was detected in all newly formed vessels and adjacent host vasculature. Our results demonstrate that nestin expression in endothelial cells lining cerebral vessels accompanies the process of angiogenesis.
Posterior cranial fossa surgery in 454 children. Comparison of results obtained in pre-CT and CT era and after various types of management of dura mater.
At the Department of Neurosurgery, Hradec Kralové, 454 children (aged under 18 years) were operated on for posterior cranial fossa lesions in a period of 49 years (1948-1996). The majority (402) had tumours: cerebellar astrocytomas 149 (37.1%), medulloblastomas 139 (34.6%), brain stem gliomas 46 (11.4%), ependymomas 28 (7.0%), and others 40 (9.9%). Postoperative mortality was compared for the pre-CT era (1948-1977) and the CT era (1978-1996): astrocytomas (8.6%:4.7%), medulloblastomas (14.9%:2.9%), brain stem gliomas (21.7%:19.0%), ependymomas (18.2%:6.3%), and others (40.0%:7.4%). The initially high mortality was due to insufficient intracranial decompression, brain oedema and disturbances of cerebrospinal fluid circulation. Obstructive hydrocephalus was treated in 53 children with tumours and 25 with aqueduct stenoses, by Torkildsen's drainage in 5.5%, and/or by catheterisation of aqueduct in 12.3%. The main postoperative complications of medial posterior fossa surgery in 429 children operated on were: pseudomeningocele (12.3%), active hydrocephalus (6.2%) and CSF leakage (4.6%). Only 8.2% had shunts placed for these complications. We presume that this low percentage of shunts used results from a frequent use of duraplasties and drains installed at the primary operation. The dura mater was initially (1948-1954) left open (50 cases), and later (1955-1958) also sutured (37 cases), and from 1958, onward, and especially from 1961, reconstructed by a medial approach by means of various grafts (377 cases). In all, duraplasty was performed in 81.6% of cases. The grafts used for dura mater reconstruction were prepared from autogeneic (1.6%), allogeneic (72.3%), xenogeneic (24.8%), or synthetic (1.3%) material. They were successful in 99.2% of cases (all materials). Our own suture technique for posterior fossa duraplasty is presented.
Choroid plexus cyst of the left lateral ventricle with intermittent blockage of the foramen of Monro, and initial invagination into the III ventricle in a child.
A cyst of the choroid plexus of the left lateral ventricle with intermittent blockage of the foramen of Monro and initially with invagination of the III ventricle in a child is described. In a 6-week-old boy a ventriculoatrial shunt was implanted for correction of an active asymmetrical hydrocephalus of unknown origin. When he was 3 months of age a water-soluble contrast CT ventriculography revealed a noncolloid cyst localised predominantly in the upper portion of the III ventricle. At that time the ventricular catheter obstructed with choroid plexus was removed; new bilateral catheters in a parieto-occipital region were implanted. In the course of the next 4 years, first the atrial catheter had to be extracted and then the peritoneal catheter was changed, in both cases because of obstruction. Periods of normal life alternated with periods of transient and intermittent symptoms of increased intracranial pressure, papilloedema, and myoclonic jerks. Repeated computed tomography (CT) and magnetic resonance imaging (MRI) showed stabilised hydrocephalus with an enlarged left lateral ventricle. When the boy was 16 years old MRI revealed a choroid plexus cyst in the left lateral ventricle 2 cm in diameter, with a ballvalve type of obstruction of the foramen of Monro. CT stereoendoscopic resection of the wall of a large cyst filled with cerebrospinal fluid was performed, and two additional adnexal small cysts were coagulated using the bipolar coagulator, Diomed 25 laser and scissors; the symptoms then regressed, except for superior bilateral altitudinal anopsia. Light and electron microscopy of the cyst wall is reported. The cyst was composed of collagenic connective tissue lined with a basal lamina lacking in epithelial cells. The preoperative and postoperative MRI are presented. Choroid plexus cysts localised in the anterior part of lateral ventricles are very rare, and all reported cases have been in male patients. According to the literature our case is only the third ever described in a child.
Not what the doctor ordered.
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Angiogenesis of extra- and intraembryonic blood vessels is associated with expression of nestin in endothelial cells.
For a long time, intermediate filament protein nestin was recognized as a specific constituent of the cytoskeleton of developing neural cells and skeletal muscle. Recent reports by other investigators demonstrated that nestin may also be expressed in other cell types. Here we give evidence that nestin is expressed by endothelial cells of developing blood vessels in the rat. Using anti-Rat-401 monoclonal antibody we identified high levels of nestin in the endothelium lining all blood vessels of E14-15 rat foetuses. Immunoreactivity for nestin was detected in both extraembryonic (chorion, placenta, umbilical cord) and intraembryonic blood vessels. In the body of the foetus, we observed nestin-positive endothelial cells in vessels located in the areas of the mesenchyme as well as in vessels supplying the developing organs (central nervous system, liver, lung, spleen, heart, digestive tube). The strongest positive signal was given by the endothelium of newly vascularized tissues. In contrast to the developing tissues, expression of nestin by vascular endothelial cells was greatly reduced in adult tissues.
Gotta know when to fold 'em. A scientific wager reveals details about how proteins fold.
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Beating bacteria. New ways to fend off antibiotic-resistant pathogens.
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Attacking arthritis. New treatments seek to rebalance the immune system.
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Hold the hormones? The good and the bad about postmenopausal estrogen therapy.
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Augmenting discord.
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I get no kick from CH3CH2OH.
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Have a heart. Tissue-engineered valves may offer a transplant alternative.
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Backfire. Could Prozac and Elavil promote tumor growth?
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[Studies on the short- and long-term tissue reaction to the root-filling material AH 26].
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