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Biomedical subjects

U Schulz

Publications and source records attributed to U Schulz.

169 records · Page 10Linked to original sources

Evidence against a major role of PEG1/MEST in Silver-Russell syndrome.

Silver-Russell syndrome (SRS) is a heterogeneous disorder characterised by interauterine and postnatal growth retardation, with or without additional dysmorphic features. Most cases are sporadic but a few familial cases have been described. A subset of patients exhibit maternal uniparental disomy for chromosome 7 (mUPD7) strongly suggesting that genomic imprinting plays a role in the aetiology of the disease. We and others have recently characterised the human PEG1/MEST gene, the first imprinted gene known to be located on chromosome 7. Although the function of PEG1/MEST is unknown, the paternal-specific expression of this gene and its location at 7q32, render it a promising candidate for SRS. As a prerequisite for mutation screening in 49 patients with SRS and 9 with primordial growth retardation (PGR), we determined the complete genomic structure of the PEG1/MEST gene which consists of 12 exons. Apart from one silent mutation and two novel polymorphisms, nucleotide changes were not detected in any of these patients. Moreover, methylation patterns of the 5' region of PEG1/MEST were found to be normal in 35 SRS and 9 PGR patients and different from the pattern seen in patients with mUPD7. These findings strongly argue against a role of PEG1/MEST in the majority of Silver-Russell syndrome cases.

Abnormalities, Multiple↗

[Venous thrombosis of cranial sinuses in asparaginase therapy. A case report].

Changes in the coagulation system due to steroids and asparaginase during treatment for acute lymphoblastic leukemia (ALL) are well known side effects and may cause bleeding or thrombosis. We report the case history of a 7-year old girl who developed thrombosis of the sinus sagittalis superior during ALL-treatment. Diagnosis was made by computed tomography and magnetic resonance imaging after the child became symptomatic with seizure. Until this event the girl had been treated already for two weeks with prednisone and E. coli-asparaginase (4 infusions). This medication caused distinct hypofibrinogenemia (Fibrinogen 53 mg/dl), prothrombin time expressed as percent of normal values of 58% was also pathological, activated partial thromboplastin time of 35 sec, antithrombin III 120% and thrombocyte count 178 G/l were in normal range. We were not successful in the attempt to adjust the imbalance in the coagulation system by transfusion of fresh frozen plasma (FFP)--seizure happened during FFP-infusion, fibrinogen blood level could be elevated only slightly. Our patient stayed consequently asymptomatic, the clinical recovery was confirmed radiologically.

Antineoplastic Combined Chemotherapy Protocols↗

Physiological and morphometric analysis of the microcirculation of the cerebral cortex under acute vasospasm.

Tissue PO2 measurements with microelectrodes and morphometric analysis of capillaries were combined to investigate microcirculatory changes in cat brains subjected to vasospasm (superfusion of platelet-poor plasma). It can be shown that vasospasm leads to marked tissue hypoxia as illustrated by a drastic shift in the PO2 distribution within the cortical tissue. Morphological measurements of various capillary parameters demonstrated a marked constriction in precapillary segments as well as in capillaries themselves. This decrease in perfusion of the capillary bed could not be compensated for by increasing the systemic arterial blood pressure. Our results demonstrate that, even with a platelet-poor fraction, marked changes occur on a microcirculatory level in the cerebral cortex with vasospasm, which may not be detected by macroscopic techniques.

Animals↗

Surgical stress and neuroendocrine responses in infants and children.

We studied the stress hormone response to surgery in 42 infants and children. Plasma levels of the stress hormones ACTH, cortisol, beta-endorphin and arginine-vasopressin (AVP) were determined on three occasions, i.e., one day before surgery, 60 to 90 minutes after skin closure and on the day after surgery (anesthesia by halothane and nitrous oxide). We observed an increase in the levels of both ACTH and cortisol in most patients after surgery, although there was no correlation between them. Beta-endorphin levels, on the other hand, rose after surgery and correlated significantly with ACTH in 30 patients. A steep rise in AVP levels was found in 84% of the subjects, a phenomenon that could not have been due only to osmotic or cardiovascular stimuli. The values of all the stress hormones declined and normalized on the day after surgery. We conclude that routine surgery in infancy or childhood induces a dramatic, albeit transient, stimulation of neuroendocrine stress hormones.

Adrenocorticotropic Hormone↗

Biocontrol strain Pseudomonas sp. W34: specific detection and quantification in the rhizosphere of Cucumis sativus with a DNA probe and genotypic characterization by DNA fingerprinting.

A DNA probe specific for biocontrol strains of Pseudomonas was produced by screening randomly amplified polymorphic DNA (RAPD) PCR fragments. Specificity of the probe was assessed by dot blot and colony hybridization. It was used to specifically determine the population of these strains on roots of Cucumis sativus cv. Delikatess. Two polymorphic RAPD fragments of 750 bp, and 550 bp showed identical specificity. The biocontrol strain Pseudomonas sp. W34 was shown to be competitive in the rhizosphere of cucumber and to maintain a stable population for at least 10 days when inoculated on the seed. The phylogenetic relationships between the biocontrol and reference strains were analyzed at the strain level by means of RAPD and repetitive sequence-based PCR genomic fingerprinting (rep-PCR), and at higher taxonomic levels by means of amplified 16S ribosomal DNA restriction analysis ARDRA. It was shown that the antagonistic strains are closely related, forming a separate cluster from other non-antagonistic and reference Pseudomonas strains, their taxonomic placement remaining uncertain.

Cucumis sativus↗