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Biomedical subjects

R Schlosser

Publications and source records attributed to R Schlosser.

8 recordsLinked to original sources
PubMed2003

Polymorphism in the peroxisome proliferator-activated receptor alpha gene influences the risk for Alzheimer's disease.

The peroxisome proliferator-activated receptor alpha (PPAR-alpha) is a member of the steroid hormone super family of ligand-inducible transcription factors, involved in glucose and lipid metabolism. We screened for polymorphisms in the PPAR-alpha gene and detected two known polymorphisms located in exon 5 and intron 7. These polymorphisms were investigated for their possible association with Alzheimer's disease (AD) and for their effect in carriers of an insulin gene (INS) polymorphism. The PPAR-alpha C --> G polymorphism in exon 5 (L162V) was associated with AD, in that the V-allele was more frequent in AD patients than in healthy subjects. Further data analysis revealed that carriers of an PPAR-alpha L162V V-allele and an INS-1 allele presented with an increased risk for AD. Cerebrospinal fluid amyloid-beta levels were influenced by PPAR-alpha L162V genotype. These results suggest, that PPAR-alpha polymorphism may be a risk factor for AD.

Aged↗
PubMed1999

Task-specific deactivation patterns in functional magnetic resonance imaging.

In general, image analysis of cognitive experiments using functional magnetic resonance imaging techniques has emphasized those regions of the brain where increases in signal intensity, with regard to the reference state, are associated with activation. Nevertheless, a number of recent papers have shown that there are areas of deactivation as well. In this study, we have used a univariate analysis and echo-planar functional magnetic resonance imaging to address the relationship of the reference state to the deactivations. We employed two dichotomous covert tasks, orthographic lexical retrieval and pure visual retrieval, to contrast with the reference state (baseline) of silent counting. Our analysis yielded extensive, task-specific landscapes of regional incremental and decremental responses. We have specifically demonstrated that the decremental responses are not due to activation in the reference state. We have also demonstrated that they are not an artifact of a specific part of the image analysis, and propose that they represent a physiological, task specific signal that should be considered an integral component of neural networks representing brain function.

Adult↗
PubMed1999

Repair of an osseous facial critical-size defect using augmented fibrin sealant.

OBJECTIVE: Osseous defects of the head and neck are a common challenge for the otolaryngologist. To develop improved reconstructive options, osteoconductive engineering experiments are being conducted. A nasal critical-size defect (CSD) model has previously been described in which less than 7% bone healing is observed over 6 months. An implant containing fibrin sealant with and without osteoprogenitor cells is evaluated in this model. STUDY DESIGN: Randomized controlled trial using a rodent model. METHODS: A nasal CSD was surgically created in 18 male retired breeder Sprague-Dawley rats. Six animals were not implanted with any material, six received fibrin sealant consisting of fibrin (25 mg/mL) and thrombin (1000 U/mL), and six were implanted with fibrin sealant and rat calvarial osteoprogenitor cells (1.8 x 10(6) cells/mL). Thirty days later, the animals were examined at necropsy by planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness. RESULTS: A thin layer of bone covered the defect in all of the treated animals. A statistically significant increase in bone density (P < .05) between fibrin sealant plus osteoprogenitor cells and each of the other groups was shown using radiodensitometric analysis. Histological analysis also confirmed this difference. CONCLUSION: Osteoprogenitor cells contained within fibrin sealant result in a greater augmentation of bone regeneration than controls or fibrin sealant alone.

Animals↗
PubMed1990

Unintentional self-intoxication with inorganic calcium.

A 40-year-old woman with previous parathyroidectomy for adenoma was found to have a serum calcium level of 5.35 mmol l-1 (21.4 mg dl-1). Inadvertent calcium overdose had occurred because of her mistaken belief that if some prescribed calcium was good, then more was better. Her misconception is in contrast with that of patients with Münchausen's syndrome, who deliberately made themselves hypercalcaemic by ingesting calcium or Vitamin D surreptitiously. Inorganic calcium is increasingly promoted for its presumed, though unproven, effectiveness in prevention and treatment of osteoporosis. Massive overdose can be associated with serious risks, as illustrated by the present case, which we believe represents the highest serum calcium level yet reported in an ambulatory patient.

Adult↗