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Biomedical subjects

J Winkler

Publications and source records attributed to J Winkler.

At least 109 records · Page 6Linked to original sources
PubMed1996

Accessing genetic information with high-density DNA arrays.

Rapid access to genetic information is central to the revolution taking place in molecular genetics. The simultaneous analysis of the entire human mitochondrial genome is described here. DNA arrays containing up to 135,000 probes complementary to the 16.6-kilobase human mitochondrial genome were generated by light-directed chemical synthesis. A two-color labeling scheme was developed that allows simultaneous comparison of a polymorphic target to a reference DNA or RNA. Complete hybridization patterns were revealed in a matter of minutes. Sequence polymorphisms were detected with single-base resolution and unprecedented efficiency. The methods described are generic and can be used to address a variety of questions in molecular genetics including gene expression, genetic linkage, and genetic variability.

Algorithms↗
PubMed1996

Variability of fatty acid content in pumpkin seeds (Cucurbita pepo L.).

Pumpkin (Cucurbita pepo L.) seed oil is a common salad oil which is produced in Slovenia, Hungary and the southern parts of Austria. It is dark green and has a high content of free fatty acids. The seed itself can be eaten. Due to its colour and the foam formation, the oil cannot be used for cooking. The content of vitamin E, especially gamma-tocopherol, is very high. The oil content of the pumpkin seed is about 50%. The variability in the oil content is very high resulting from a broad genetic diversity. Thus a breeding programme for increasing the oil productivity is very promising. The four dominant fatty acids are palmitic, stearic, oleic and linoleic acids. These four fatty acids make up 98 +/- 0.13% of the total amount of fatty acids, others being found at levels well below 0.5%.

Austria↗
PubMed1996

Variability of vitamin E content in pumpkin seeds (Cucurbita pepo L.).

Pumpkin (Cucurbita pepo L.) seed oil is a common salad oil which is produced in the southern parts of Austria, Slovenia and Hungary. It is dark green and has a high content of free fatty acids. Due to its colour, the oil cannot be used for cooking. The content of vitamin E, especially gamma-tocopherol, is very high. The oil content of the pumpkin seed is about 50%. The seed itself can be eaten. Therefore a pumpkin variety with high vitamin E content is desirable. The aim of this work was to find a variety of Cucurbita pepo which has a high oil yield and a high vitamin E content. A total of 100 breeding lines were tested for their tocopherol content. The tocopherols and tocotrienols are extracted with hexane and analysed by NP-HPLC/FLD with hexane/dioxan (96/4) as eluent, with fluorescence detection at 292/335 nm. The gamma-tocopherol content, which is about 5-10 times as much as that of alpha-tocopherol varies over a broad range (41-620 mg/kg dry pumpkin seeds). Beta- and delta-tocopherol are found at low levels.

Chromatography, High Pressure Liquid↗
PubMed1995

Essential role of neocortical acetylcholine in spatial memory.

The cholinergic system plays a crucial role in learning and memory. Lesions of cholinergic nuclei, pharmacological manipulations of cholinergic systems, intracerebral transplantation of fetal tissue and anatomical changes in cholinergic pathways during ageing have all been correlated with altered cognitive behaviour. However, it has not been proved that regional acetylcholine is causally required for learning and memory. Here we describe how we achieved a permanent and selective impairment of learning and memory by damaging the nucleus basalis magnocellularis, a nucleus that provides the major cholinergic innervation of the neocortex, in adult rats. To test the hypothesis that acetylcholine is essential for restoration of cognitive function, we implanted genetically modified cells that produce acetylcholine into denervated neocortical target regions. After grafting, rats with increased neocortical acetylcholine levels showed a significant improvement in a spatial navigation task. Acetylcholine is thus not only necessary for learning and memory, as previously argued, but its presence within the neocortex is also sufficient to ameliorate learning deficits and restore memory following damage to the nucleus basalis.

Acetylcholine↗
PubMed1995

Effects of nerve growth factor treatment on rats with lesions of the nucleus basalis magnocellularis produced by ibotenic acid, quisqualic acid, and AMPA.

Rats with bilateral lesions of the nucleus basalis magnocellularis (NBM) produced by ibotenic acid (IBO), quisqualic acid (QUIS), and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) received either human recombinant nerve growth factor (NGF) (5.0 micrograms/day) or cytochrome c (cc) (0.3 microgram/day) treatment. Spatial memory impairments in the Morris water maze differed for the three toxins in the following order: IBO-cc > AMPA-cc > QUIS-cc. Treatment with NGF resulted in behavioral improvement for only the IBO-lesioned rats. Body weight was not affected by the different lesions before treatment; however, administration of NGF resulted in a decreased rate of body weight gain independent of the excitotoxin used. Reduction in choline acetyltransferase (ChAT) activity differed in the neocortex for the three toxins, whereas the hippocampus was unaffected. The cortical ChAT depletion was greatest for AMPA, intermediate for QUIS, and least for IBO. Restoration of ChAT activity by NGF differed for the three toxins (QUIS-NGF > IBO-NGF > AMPA-NGF), whereas ChAT activity in the hippocampus was increased equally. The loss of low-affinity NGF-receptor (p75NGFr)-immunoreactive neurons differed for the toxins (AMPA-cc > QUIS-cc > IBO-cc), whereas treatment with NGF increased the size of the remaining neurons independently of the used toxin. NGF induced a p75NGFr-immunoreactive thickening around intracerebral arteries for all three toxins. Lesions of the NBM produced by IBO, QUIS, and AMPA resulted in a quantitatively different pattern of behavioral, biochemical, and histological deficits. The quantitatively different pattern of recovery after administration of NGF may be determined by the responsivity of the remaining neurons. Intracerebroventricular administration of NGF affected noncholinergic systems as well, resulting in decreased food intake and cerebrovascular hyperinnervation.

Animals↗
PubMed1995

Tetrameric structure and cellular location of catechol 2,3-dioxygenase.

Catechol 2,3-dioxygenase from the meta-cleavage pathway encoded on the TOL plasmid of Pseudomonas putida (pWWO) was investigated by electron microscopy. Negatively stained samples of the purified catechol 2,3-dioxygenase revealed that the enzyme consists of four subunits arranged in a tetrahedral conformation. Monoclonal antibodies raised against catechol 2,3-dioxygenase showed highly specific reactions and were used to localize the enzyme in Escherichia coli (pAW31) and P. putida (pWWO), using the protein A-gold technique carried out as a post-embedding immunoelectron microscopy procedure. Our in situ labeling studies revealed a cytoplasmic location of the catechol 2,3-dioxygenase in both cell types.

Antibodies, Monoclonal↗
PubMed1995

Tracking the Response of Burkholderia cepacia G4 5223-PR1 in Aquifer Microcosms.

The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of microbial population dynamics to define persistence and activity from both efficacy and risk assessment perspectives. Burkholderia cepacia G4 5223-PR1 is a Tn5 insertion mutant which constitutively expresses a toluene ortho-monooxygenase that degrades trichloroethylene (TCE). This ability of G4 5223-PR1 to degrade TCE without aromatic induction may be useful for bioremediation of TCE-containing aquifers and groundwater. Thus, a simulated aquifer sediment system and groundwater microcosms were used to monitor the survival of G4 5223-PR1. The fate of G4 5223-PR1 in sediment was monitored by indirect immunofluorescence microscopy, a colony blot assay, and growth on selective medium. G4 5223-PR1 was detected immunologically by using a highly specific monoclonal antibody which reacted against the O-specific polysaccharide chain of the lipopolysaccharides of this organism. G4 5223-PR1 survived well in sterilized groundwater, although in nonsterile groundwater microcosms rapid decreases in the G4 5223-PR1 cell population were observed. Ten days after inoculation no G4 5223-PR1 cells could be detected by selective plating or immunofluorescence. G4 5223-PR1 survival was greater in a nonsterile aquifer sediment microcosm, although after 22 days of elution the number of G4 5223-PR1 cells was low. Our results demonstrate the utility of monoclonal antibody tracking methods and the importance of biotic interactions in determining the persistence of introduced microorganisms.

Journal Article↗
PubMed1995

The molecular architecture of focal adhesions.

This article outlines the present knowledge of the architecture, molecular composition, and dynamics of focal contacts of adhesive animal cells. These structures, developed at the plasma membrane at sites where cells touch their substratum, are essential for cellular attachment in tissue formation during embryogenesis and wound healing. In tissue culture, they are particularly prominent and thus amenable to detailed investigation. Focal contacts consist of a cytoplasmic face, comprising cytoskeletal elements, a transmembrane connecting region, and a extracellular face composed of proteins of the extracellular matrix. The molecular anatomy of the numerous proteins involved, the basis for classifying them as structural or regulatory components, and their in vitro interactions are described. Based on this information, current models on the dynamics of their assembly and of possible regulatory mechanisms involving a variety of signal transduction pathways are discussed.

Actins↗
PubMed1994

Effects of residual renal function in haemodialysis patients.

Thirty-six haemodialysis patients on treatment for more than six months were studied for residual renal function (RRF). Twenty patients were anuric. The remaining 16 patients with RRF excreted 35-1600 ml urine/day with creatinine clearance ranging 0.17-6.95 ml/min. Patients with RRF were on dialysis therapy for shorter periods than those with anuria (25.5 +/- 18.5 vs. 101.7 +/- 14.2 months, p = 0.001). Twelve out of 20 anuric patients had had previous renal transplantation, whereas none of those with RRF had been transplanted (p = 0.0006). Interdialytic weight gain, serum potassium and phosphate were lower in patients with RRF. Serum phosphate and uric acid were correlated with their respective urinary excretion rates (p = 0.013 and 0.005, respectively), but interdialytic weight gain could not be correlated with urinary output. Creatinine clearance significantly correlated with urinary excretion of potassium, sodium, phosphate and uric acid. In this series of patients a previous unsuccessful renal transplantation was an important factor in the loss of RRF. The presence of RRF contributed to the regulation of the blood levels of phosphate and the excretion rate of potassium, sodium and uric acid.

Blood Urea Nitrogen↗
PubMed1994

Grafting of nerve growth factor-producing fibroblasts reduces behavioral deficits in rats with lesions of the nucleus basalis magnocellularis.

Rats received bilateral lesions of the nucleus basalis magnocellularis by infusion of biotenic acid. Two weeks after the lesion, a suspension of genetically modified primary rat fibroblasts was grafted dorsal to the nucleus basalis magnocellularis (2 x 10(5) cells per side). The fibroblasts were either infected with the gene for human beta-nerve growth factor or Escherichia coli beta-galactosidase. The nerve growth factor-producing fibroblasts released 67 ng nerve growth factor/10(5) cells per day in vitro. Two weeks after implantation of the fibroblasts, spatial learning was tested in the Morris water-maze. Nerve growth factor-producing fibroblasts, but not beta-galactosidase-producing fibroblasts ameliorated the deficit in acquisition of the water-maze task. In addition, spatial acuity was improved to near-normal levels by the nerve growth factor-producing grafts. Choline acetyltransferase activity in cortical areas and hippocampus was not affected by the nerve growth factor-producing grafts. Both grafted groups showed a similar reduction in the level of dopamine, but not homovanillic acid or 3-methoxytyramine, in the frontal cortex. Levels of norepinephrine, epinephrine and serotonin and their metabolites in the neocortex and hippocampus were not affected by the lesion or the grafts. Nerve growth factor-producing grafts increased the size of remaining nerve growth factor-receptor (p75) immunoreactive neurons in the nucleus basalis magnocellularis by 25%. Nucleus basalis magnocellularis lesions reduced the integrated optic density of choline acetyltransferase-positive fiber staining in the ventral neocortex by 46%, but nerve growth factor-producing grafts restored this area to 86% of control. These data suggest that nerve growth factor-producing grafts can cause a marked behavioral improvement, probably through the partial restoration of the lesioned projection from nucleus basalis magnocellularis to neocortex.

Animals↗
PubMed1994

Surgical intervention and heparin-anticoagulation improve prognosis of rhinogenic/otogenic and posttraumatic meningitis.

It is still controversial, whether early surgical removal of infectious material and heparin-anticoagulation to reduce vascular complications will improve outcome in acute meningitis. In the present pilot-study 40 patients with acute or delayed post-traumatic or oto-/rhinogenic purulent bacterial meningitis were analysed for neurological outcome by using the Glasgow outcome score (GOS) and the Tuthill functional score; patients were treated either by early surgical revision of the septic focus (Group 1, within 6 days, n = 15), late surgery (Group 2, later than 6 days, n = 19), or no surgery at all (Group 3, n = 6). All patients, independent of surgical approach, received therapeutic heparin-anticoagulation. Patient groups were otherwise comparable for antibiotic treatment, osmotherapy, microbiology, CSF-findings, CT-scans and prognostic factors. Outcome according to GOS was superior in Group 1 compared with Groups 2/3 (non-significant). Although there was no significant difference on admission in the Tuthill functional score, Group 1 achieved a superior final outcome of 96 points compared with Groups 2 and 3, who gained 72 points (p < 0.01). In addition, Group 1 patients had significantly less intracranial complications (8/15 patients versus 21/25 patients in Groups 2/3, p < 0.01) and were dependent upon respirator treatment for fewer days (10.2 days) than Groups 2/3 (12.5 days, non-significant). In 31 patients CSF-leakage was identified: among these, 17 patients had CSF-leakage, which had not been anticipated by clinical/neuroradiological examinations and revealed only by surgery. The overall mortality in this study population was very low (2.5%), therefore, therapeutic heparin seems to represent an additional favorable treatment measure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Adequacy of dialysis and nutritional status in hemodialysis patients.

Twenty-three nondiabetic end-stage renal failure patients on hemodialysis were studied for adequacy of dialysis and nutritional status. Midweek predialysis blood urea nitrogen was 27.1 +/- 6.4 mmol/l of urea, KT/V, according to urea kinetic modelling, was 1.21 +/- 0.22 and mean normalized protein catabolic rate (nPCR) was 1.15 +/- 0.23 g/kg/day. Only 1 patient had a KT/V less than 1 and 4 patients had an nPCR less than 1 g/kg/day. No correlation was found between the different nutritional parameters. All patients had normal serum albumin. However, some of the patients could be classified as severely malnourished when parameters such as body weight (2 patients), triceps skinfold (5) and total lymphocyte count (3) were taken into account. No correlation was found between adequacy of dialysis and the different nutritional parameters. Furthermore, when patients were divided into low and normal KT/V, no differences were found in their nPCR. We conclude that a global assessment of the nutritional status is required in hemodialysis patients, and at least in patients with an acceptable KT/V, nPCR is not dependent on the adequacy of dialysis.

Adult↗
PubMed1993

Autoinduction of platelet derived growth factor (PDGF) A-chain mRNA expression in a human malignant melanoma cell line and growth inhibitory effects of PDGF-A-chain mRNA-specific antisense molecules.

Autoinduction of PDGF-A-chain mRNA's was demonstrated in cells of a human malignant melanoma cell line (HTZ 19), indicating a PDGF-induced amplification of an autocrine growth factor loop mechanism. PDGF-alpha receptors were detected by immunocytochemistry in HTZ 19 melanoma cells. Exogenously administered PDGF-AA exerted an increase in cell proliferation by 70% at 200 ng/ml PDGF in serum-supplemented cell culture medium. Antisense phosphorothioate-oligodeoxynucleotides (S-ODN's), specifically targeted against PDGF-A-chain mRNA, reduced cell proliferation of HTZ 19 melanoma cells by 62% at a concentration of 5.0 microM, also only in serum-enriched medium. These findings strongly suggest that PDGF-AA homodimers may be an autocrine growth factor for HTZ 19 melanoma cells but require synergistic interaction with serum components.

Base Sequence↗
PubMed1993

Differentiation between ischemic and hemorrhagic stroke by transcranial color-coded real-time sonography.

Transcranial color-coded real-time sonography was applied to 20 patients with ischemic stroke and 28 patients with spontaneous intracerebral hemorrhage. In all patients the sonographic diagnosis corresponded closely to cranial computed tomography findings. Recent hemorrhages were visualized as a hyperechodense mass. The high contrast to minor echodense adjacent parenchyma led to a clear sonographic distinction. Older clots were characterized by a continuous decrease of echodensity and subsequently were interspersed by hypoechodense zones. In the acute stage of ischemic infarction, the vessel occlusion (17/20) and collateral vascular supply (10/20) could be depicted in the color-B-mode in two perpendicular planes and further verified by the Doppler mode. Brain edema was not visualized. Although in the acute stage no change of echo texture was observed within the infarction, hyperechodense regions (7/11) could be observed in some patients during the time course. Complications of intracerebral hemorrhage and ischemic stroke, such as disturbance of cerebrospinal fluid circulation, midline shift, and compression of adjacent territories, were depicted by transcranial color-coded sonography. These preliminary results illustrate that transcranial color-coded real-time sonography may be helpful in the early noninvasive differential diagnosis as well as long-term follow-up in patients with cerebrovascular disorders.

Brain Ischemia↗
PubMed1993

Bacteremia complicating peritonitis in peritoneal dialysis patients.

Bacteremia is a rare complication of peritonitis in end-stage renal failure (ESRF) patients treated by peritoneal dialysis. Three of our ESRF patients on peritoneal dialysis developed bacteremia during a peritonitis episode (1/19 peritonitis episodes). In 2 cases, the responsible organism was Escherichia coli and peritonitis was most likely associated with infection of the biliary tract. The 3rd patient had a perforation of the colon and Klebsiella spp. was the infective organism. Only the last patient survived but had to be transferred to hemodialysis. Bacteremia during peritonitis is infrequent in peritoneal dialysis patients and it appears to be related to other intra-abdominal events.

Aged↗
PubMed1993

Compliance in hemodialysis patients: a multivariate regression analysis.

Successful treatment of patients with end-stage renal failure requires, in addition to dialysis, strict control of dietary, fluid and medication intake. In the present study we measured, in 50 chronic hemodialysis patients, serum potassium (K), serum phosphate (PO4) and interdialytic weight gain as indices of diet, medication and fluid compliance, respectively. Dietary compliance did not correlate with fluid or medication compliance, whereas fluid intake and medication compliance were related (p = 0.01). Age, time on dialysis, place of birth and whether the patient came accompanied or not to the dialysis unit were the main variables affecting serum K levels. Sex, ethnic origin and education significantly affected serum PO4. Sex, place of birth, marital status, number of children and years of education affected fluid intake. The compliance of the hemodialysis patient with different aspects of his regimen is thus multifactorial. Attempts to improve compliance and thus reduce morbidity and mortality should be aimed at identifying the population with low compliance and exposing them to educational programs.

Adult↗