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Biomedical subjects

S Schwarz

Publications and source records attributed to S Schwarz.

At least 127 records · Page 7Linked to original sources
PubMed1999

17Beta-hydroxy-11alpha-(3'-sulfanylpropyl)oxy-estra-1,3,5(10)- trien-3-yl sulfamate--a novel hapten structure: toward the development of a specific enzyme immunoassay (EIA) for estra-1,3,5(10)-triene-3-yl sulfamates.

The title compound 17 has been synthesized for the use as hapten in the development of a competitive enzyme immunoassay for estrogen sulfamates. The synthesis started from estradiol diacetate 2. Oxyfunctionalization at C-11 to give 11alpha-hydroxy steroid 8 was accomplished by hydroboration/alkaline hydrogen peroxide oxidation of the 9(11)-dehydro derivative 7, which was obtained from compound 2 via 9-hydroxylation with dimethyldioxirane. After transformation of compound 8 into the allyl ether 9, the side chain was thio-functionalized at the omega-position affording the thioate 11 in two steps. Selective silylether deprotection at position 3 followed by sulfamoylation gave the sulfamate 19, which in turn was demasked at position 17 and treated with sodium borohydride/aluminum chloride to liberate the side chain thiol. Alternatively, title compound 17 was synthesized via the disulfides 13-16. For the preparation of the immunogen the title compound 17 was coupled to bovine gamma globulin in a two-step procedure using an amine and thiol specific bifunctional crosslinker. The immunization of rabbits resulted in the formation of antibodies which clearly discriminated the sulfamoylated estrogens from the non-esterified estrogens. The use of a biotinylated hapten derivative as a tracer in combination with a streptavidin-peroxidase-tetramethylbenzidine based detection system allowed the measurement of estradiol 3-sulfamate (1) in the range of about 1 to 1000 pg/well.

Animals↗
PubMed1999

Complications following the use of the Combitube, tracheal tube and laryngeal mask airway.

In a prospective, randomised trial, 75 patients scheduled for routine surgery were randomly allocated to one of three groups to evaluate trauma and postoperative complications after insertion of the Combitube, tracheal tube or laryngeal mask airway. Insertion of the Combitube was associated with a higher incidence of sore throat (48% vs. 16% vs. 12% [p < 0.01]) and dysphagia (68% vs. 12% vs. 8% [p < 0.01]) compared with tracheal intubation or insertion of the laryngeal mask airway, respectively. Hoarseness was significantly less common in both the Combitube and the laryngeal mask groups (both 12%) than in the tracheal tube group (44%; p < 0.01). Haematoma occurred in 36% of the Combitube group compared with 4% in both the laryngeal mask and the tracheal tube groups (p < 0.01). The higher incidence of complications should be considered when using the Combitube.

Adult↗
PubMed1999

Host range of the ermF rRNA methylase gene in bacteria of human and animal origin.

We screened 183 different clinical anaerobic and aerobic bacteria isolated from humans and other animals for the presence of the ermF gene using a polymerase chain reaction (PCR) assay. The ermF gene was detected in 107 (58%) clinical isolates, including 42 (61%) of 69 gram-positive bacteria and 65 (57%) of 114 gram-negative bacteria. Twenty-five ATCC isolates were also tested; 20 (80%) carried the ermF gene. The gene products from the ermF PCR from four isolates were sequenced and showed 95-99% nucleotide homology with the ermF gene and 98-99% amino acid homology with the gene product. Eleven (58%) of the 19 gram-negative donors tested were able to transfer the ermF gene. All nine (100%) of the gram-positive donors tested transferred the ermF gene, using either Enterococcus faecalis or Haemophilus influenzae as the recipients.

Animals↗
PubMed1999

Hemodynamic and catecholamine stress responses to insertion of the Combitube, laryngeal mask airway or tracheal intubation.

UNLABELLED: In a prospective, randomized, and controlled trial, we compared the stress responses after insertion of the Combitube (CT; Kendall-Sheridan Catheter Corp., Argyle, NY), the laryngeal mask airway (LMA), or endotracheal intubation (ET). Seventy-five patients scheduled for routine urological or gynecological surgery were randomly allocated to one of three groups and were ventilated via either an ET, a LMA, or a CT. All three devices could be inserted easily and rapidly, providing adequate ventilation and oxygenation. Insertion of the CT was associated with a significant increase in mean maximal systolic arterial pressure (160+/-32 mm Hg) and diastolic arterial pressure (91+/-17 mm Hg) compared with ET (140+/-24, 78+/-11 mm Hg; P < 0.05, P < 0.01, respectively) or insertion of the LMA (115+/-33,63+/-22 mm Hg, both P < 0.001). The mean maximal epinephrine and norepinephrine plasma concentrations after insertion of the CT (37.3+/-31.1 and 279+/-139 pg/mL, respectively) were significantly higher than those after ET (35.8+/-89.8 and 195+/-58 pg/mL, respectively) or insertion of a LMA (17.3+/-13.3 and 158+/-67 pg/mL, respectively). This might be attributed to the pressure of the pharyngeal cuff of the CT on the anterior pharyngeal wall. We conclude that insertion of the CT causes a pronounced stress response and that precautions should be taken when used in patients at risk of hypertensive bleeding. IMPLICATIONS: In this study, we showed that the hemodynamic and catecholamine stress responses after insertion of the Combitube (Kendall-Sheridan Catheter Corp., Argyle, NY) were significantly higher compared with laryngeal mask airway or endotracheal intubation. We conclude that the increased stress response to insertion of a Combitube may represent a serious hazard to patients with cardiovascular disease.

Adult↗
PubMed1999

Favorable recovery from bilateral loss of somatosensory evoked potentials.

OBJECTIVES: Bilateral loss of the cortical somatosensory evoked potentials (SEP) is usually regarded as a strong predictor for a very poor clinical outcome. We present four patients with a favorable recovery from bilaterally absent cortical SEP. DESIGN: Case series. SETTING: Neurocritical care unit at the University of Heidelberg. PATIENTS: Four patients with viral encephalitis, carbamazepine intoxication, head trauma, and left-side, space-occupying hemispheric infarction, respectively. INTERVENTIONS: Serial recording of somatosensory and auditory evoked potentials, therapy of increased intracranial pressure, including decompressive surgery, hypothermia, and barbiturate coma. MEASUREMENTS AND MAIN RESULTS: Three patients had an excellent outcome (Glasgow Outcome Scale 4 and 5). In those three patients, the SEP became completely normal during the clinical course. In one patient who remained severely disabled, the SEP became detectable again over the contralateral hemisphere, but remained abnormal. Possible influencing factors were sedative and analgetic drugs in all patients, and hypothermia and barbiturate coma in one of the patients. CONCLUSIONS: The absence of cortical SEP does not invariably imply an unfavorable prognosis. Absent cortical SEP indicates a severe neuronal dysfunction, which may be completely reversible if the underlying disease does not lead to permanent structural damage.

Acute Disease↗
PubMed1999

Structural alterations in the translational attenuator of constitutively expressed ermC genes.

Sequence deletions of 16, 59, and 111 bp as well as a tandem duplication of 272 bp with respect to the corresponding sequence of pT48 were identified in the regulatory regions of constitutively expressed ermC genes. Constitutive ermC gene expression as a consequence of these structural alterations is based on either the prevention of the formation of mRNA secondary structures in the translational attenuator or the preferential formation of those mRNA secondary structures which do not interfere with the translation of the ermC transcripts. A model for the development of sequence deletions in the ermC translational attenuator by homologous recombination is presented and experimentally tested by in vitro selection of constitutively expressed mutants in staphylococcal strains deficient and proficient in homologous recombination.

Animals↗
PubMed1999

Calcium antagonistic effect of 17 alpha-estradiol derivatives: in vitro examinations.

The calcium antagonistic effect of 17 alpha-estradiol derivatives was investigated in vitro in human aortic smooth muscle cells. The substances tested were 17 alpha-estradiol, 17 alpha-ethinylestradiol, the scavestrogens J811 and J861, and 17 beta-estradiol. Examinations were carried out by measuring 45Ca influx into the cells. All compounds showed a significant inhibition of calcium influx at the concentration of 10(-6) M. The strongest effect could be registered for the scavestrogens. Since these substances are virtually devoid of estrogenic activity, they may offer advantages over 17 beta-estradiol in the therapy and prevention of cardiovascular disease.

Antioxidants↗
PubMed1998

Electric fish measure distance in the dark.

Distance determination in animals can be achieved by visual or non-visual cues. Weakly electric fish use active electrolocation for orientation in the dark. By perceiving self-produced electric signals with epidermal electroreceptors, fish can detect, locate and analyse nearby objects. Distance discrimination, however, was thought to be hardly possible because it was assumed that confusing ambiguity could arise with objects of unknown sizes and materials. Here we show that during electrolocation electric fish can measure the distance of most objects accurately, independently of size, shape and material. Measurements of the 'electric image' projected onto the skin surface during electrolocation revealed only one parameter combination that was unambiguously related to object distance: the ratio between maximal image slope and maximal image amplitude. However, slope-to-amplitude ratios for spheres were always smaller than those for other objects. As predicted, these objects were erroneously judged by the fish to be further away than all other objects at an identical distance. Our results suggest a novel mechanism for depth perception that can be achieved with a single, stationary two-dimensional array of detectors.

Animals↗
PubMed1998

Molecular characterization of Salmonella enterica subsp. enterica serovar Typhimurium DT009 isolates: differentiation of the live vaccine strain Zoosaloral from field isolates.

A total of 25 epidemiologically unrelated Salmonella enterica subsp. enterica (S.) serovar Typhimurium DT009 isolates from various human and animal sources, the original S. Typhimurium DT009 Zoosaloral live vaccine strain and two Zoosaloral strains reisolated from vaccinated chickens were investigated by various molecular typing methods (I) to determine the most suitable method or combination of methods for the differentiation of DT009 field isolates and (II) to investigate which molecular methods are suitable to differentiate the Zoosaloral live vaccine strain from field isolates of the same phage type. Based on the results of plasmid profile analysis, IS200 typing and macrorestriction analysis with XbaI, SpeI and BlnI, the 28 S. Typhimurium DT009 isolates were assigned to 16 different genomic groups, one of which was exclusively represented by the original and the reisolated Zoosaloral strains. IS200 typing was the most discriminatory single method for the differentiation of the DT009 isolates followed by plasmid profile analysis and BlnI-macrorestriction analysis. The Zoosaloral vaccine strain differed from the DT009 field isolates by its unique HindIII-fragment pattern of the virulence plasmid and by its unique SpeI-macrorestriction pattern.

Animals↗
PubMed1998

Molecular typing of Salmonella enterica subsp. enterica serovar Hadar: evaluation and application of different typing methods.

A highly discriminatory molecular typing system for isolates of Salmonella enterica subsp. enterica (S.) serovar Hadar was developed based on the data obtained from 34 epidemiologically unrelated S. Hadar isolates from Germany and Brazil. Plasmid profile analysis and macrorestriction analysis with the enzymes XbaI, SpeI and BlnI represented the most discriminative typing methods. In contrast, ribotyping as performed with a gene probe that recognized the entire rrn operon did not reveal any differences between the S. Hadar isolates. IS200 typing was not applicable due to the lack of insertion elements of this type in all S. Hadar isolates included in this study. The combination of the results of plasmid analysis and macrorestriction analysis subdivided the 34 S. Hadar isolates into 32 different genomic groups. The high discriminatory power of these methods confirmed their suitability as effective typing methods for epidemiological studies on S. Hadar isolates. The practical application of this molecular typing system to S. Hadar isolates of the same flock obtained during a 15 month period strongly suggested recurring introduction of genomically different S. Hadar isolates instead of a single introduction of S. Hadar followed by subsequent spread within the flock.

Animals↗
PubMed1998

A novel 52 kDa protein induces apoptosis and concurrently activates c-Jun N-terminal kinase 1 (JNK1) in mouse C3H10T1/2 fibroblasts.

A 52 kDa protein (p52) was purified from chicken embryos and its corresponding cDNA was cloned. The p52 cDNA is 1768 bp long and has an open reading frame of 465 amino acids. The sequence of the p52 cDNA shows significant homology with mouse and human cDNAs from the EST database, so do the deduced amino acid sequences, indicating the existence of human and mouse homologues of p52. Northern blot hybridization showed that the p52 mRNA was expressed in a wide range of embryonic and adult tissues. There was more p52 mRNA in embryonic heart and liver than in the brain or muscle. The adult testis had the highest level of p52 mRNA, whereas adult liver had the lowest. Expression of p52 in mouse C3H10T1/2 fibroblasts caused apoptotic cell death, upregulation of transcription factor c-Jun and activation of c-Jun N-terminal kinase 1 (JNK1). In addition, expression of Bcl-2, but not of the dominant negative mutant JNK1, can block the p52-mediated apoptosis. These results indicate that p52 may represent a new cell-death protein inducing apoptosis and activating JNK1 through different pathways.

Amino Acid Sequence↗
PubMed1998

Moderate hypothermia and brain temperature in patients with severe middle cerebral artery infarction.

Elevated temperature is known to facilitate neuronal injury after ischemia. After head injury a gradient between temperature and body temperature of up to 3 degrees C higher in the brain has been reported. Hypothermia may limit some of the deleterious metabolic consequences of such increased temperature. In 20 patients who had suffered severe ischemic stroke in the middle cerebral artery (MCA) territory, intracerebral temperature combined with ICP monitoring was recorded using two different thermocouples, with epidural, and parenchymatous measurements. Mild hypothermia was induced using cooling blankets. Patients were kept at 33 degrees C core temperature for 48 to 72 hours. In all patients brain temperature exceeded body-core temperature by at least up to 1 degree C (range 1.0-2.1 degrees C). Systemic cooling was effective and sustained hypothermic (33-34 degrees C) brain temperatures. With mild hypothermia critically elevated ICP values could be controlled. 12 patients survived the hemispheric stroke with a mean Barthel index of 70. Severe side effects of hypothermia were not detected. After MCA stroke, human intracerebral temperature is higher than central body-core temperature. Mild hypothermia in the treatment of severe cerebral ischemia using cooling blankets is safe and does not lead to severe side effects. Mild hypothermia can help to control critically elevated ICP values in severe space-occupying stroke and may improve clinical outcome in these patients.

Adult↗
PubMed1998

The remarkable influence of steroid A/B-ring junction on the Wittig olefination reaction of the 11-oxo group: towards the synthesis of 5 alpha- and 5 beta-oriented delta 3-isomers of desogestrel.

The 5 alpha- and 5 beta-oriented delta 3-double bond isomers 8, 9 of the widely used progestin desogestrel (7) were synthesized. Wittig olefination reaction of the 5 alpha-intermediate 12 showed a dramatically reduced reaction rate compared with the olefination of the 5 beta-intermediate 13. Computational studies suggest that different energies of the intermediary 1,2-oxaphosphetanes may, at least partially, have been the reason for this phenomenon.

Alkenes↗