Search PubMed⌕ Search

Biomedical subjects

J Peters

Publications and source records attributed to J Peters.

At least 325 records · Page 18Linked to original sources
PubMed1995

Myositis and fasciitis associated with group A beta hemolytic streptococcal infections: development of a rabbit model.

Group A streptococci produce a variety of clinical symptoms ranging from minor pharyngeal infections to life-threatening soft-tissue disease. A rabbit model is described for induction of myonecrosis and fasciitis with group A beta-hemolytic streptococci. Group A streptococcal infections have shown remarkable virulence in recent years, resulting in severe local tissue destruction and life-threatening toxicity. After subcutaneous injection into the thigh of 20 ml broth containing 10(5) to 10(9) cfu/ml, initial soft tissue infection rapidly progressed to rhabdomyolysis. The response of the rabbits to the infection was consistent with the human response.

Adult↗
PubMed1995

[Detection and side effects of isoantibodies in intravenously administered immunoglobulin preparations].

BACKGROUND: Intravenous immunoglobulins (IvIg) contain not only the declared antibodies against pathogenic microorganisms, but also all the other antibodies of the blood donors, e.g. against erythrocytic antigens. MATERIALS AND METHODS: We tested 14 IvIg from 7 manufacturers (a total of 40 charges) for isoantibodies and irregular antibodies. To improve the reading of our tests we used the gel centrifugation method (ID-Microtyping-System, Fa. Diamed, Bensheim, Germany). RESULTS: The highest isoantibody titers were (in 8 charges) 1:32 or 1:64 in the Liss-Coombs test. Irregular antibodies were found in 5 IvIg (maximal titer 1:8). CONCLUSIONS: Isoantibodies in the IvIg can influence blood group serologic tests. With an example of a newborn who had received IvIg we point to the potential danger of misinterpretation of a positive direct antiglobulin test after administration of IvIg. Therefore we recommend to carry out the direct antiglobulin test before administration of IvIg and to examine all eluates after a positive direct Coombs test not only with 0 RBCs but also with A or B RBCs of the AB0 blood group of the patient.

ABO Blood-Group System↗
PubMed1995

Preliminary descriptions of transient-evoked and distortion-product otoacoustic emissions from graduates of an intensive care nursery.

Transient-evoked (TEOAE) and distortion-product otoacoustic emissions (DPOAE) were measured in 51 graduates of an intensive care nursery and compared to data obtained from 80 normal-hearing children and adults. All infants had click-evoked auditory brainstem responses (ABR) at 30 dB nHL or less while the older subjects had pure-tone thresholds of 20 dB HL or less for octave frequencies from 250 to 8000 Hz. OAE data were collected using commercially available devices. All data were analyzed in terms of emission amplitude, emission-to-noise ratio, and response reproducibility as a function of frequency. DPOAEs were measured at three points per octave between f2 frequencies of approximately 500 and 8000 Hz. TEOAEs were elicited by clicks and were analyzed in both octave and 1/3-octave bands centered at frequencies from 500 to 4000 Hz, as well as in the broadband condition. In addition, stimulus amplitudes for the clicks used to elicit TEOAEs were analyzed within octave and 1/3-octave bands to determine whether any age-related differences in responses can be accounted for on the basis of stimulus differences. Both emission amplitude and noise amplitude were greater in neonates than adults, although there was variability across frequency. Emission-to-noise ratio and response reproducibility were more similar between groups. For TEOAEs, high-frequency emission-to-noise ratios were larger in neonates compared to older subjects, while the reverse was true in the lower frequencies. Less obvious frequency effects were observed for DPOAEs. These findings are discussed in relation to the potential use of OAEs as screening measures for neonatal hearing loss.

Acoustic Stimulation↗
PubMed1994

Solubilization of the overexpressed integral membrane protein alkane monooxygenase of the recombinant Escherichia coli W3110[pGEc47].

The integral membrane-bound alkane monooxygenase (AlkB) from Pseudomonas oleovorans has been overexpressed in the recombinant Escherichia coli strain W3110[pGEc47] and expression levels of 10 to 15% relative to the total cell protein were reached. The amount of phospholipids in induced cells is about 3-fold higher compared to the wild-type and AlkB has been shown to be located in small membrane vesicles. We present here a study on the solubilization of these AlkB containing membrane vesicles by different detergents with special emphasis on structural requirements for a surfactant preserving the activity of AlkB. Moreover, the effects of the detergents used on the complete alkane hydroxylase system was studied.

Bacterial Outer Membrane Proteins↗
PubMed1994

Primary structure of a multimeric protein, homologous to the PEP-utilizing enzyme family and isolated from a hyperthermophilic archaebacterium.

A large protein complex (approx. 2000 kDa) was found in the cytosol of the hyperthermophilic archaebacterium Staphylothermus marinus. The purified protein was shown to be a homomultimer of 93 kDa subunits, the primary structure of which was determined by nucleotide sequence analysis. The protein belongs to the family of phosphoenolpyruvate-utilizing enzymes and represents the first member characterized in archaebacteria. Its homomultimeric organisation differs from the typically dimeric structure of its eubacterial and eukaryotic counterparts.

Amino Acid Sequence↗
PubMed1994

Protective protein for beta-galactosidase, Ppgb, maps to the distal imprinting region of mouse chromosome 2 but is not imprinted.

Human chromosome 20 is conserved as a single segment on distal mouse chromosome (Chr) 2. PPGB, protective protein for beta-galactosidase, maps to human chromosome 20q13.1, and from linkage analysis of two interspecific crosses incorporating the mouse reciprocal translocations, T(2;8)2Wa (T2Wa) and T(2;16)28H (T28H), we have mapped the mouse homologue, Ppgb, to the conserved region on distal mouse Chr 2. From the combined data, the order of markers is T2Wa-Ada-Ppgb-D2Mit25-T28H. Loci mapping between the T2Wa and T28H breakpoints lie in a region that is subject to parental imprinting, and so expression of Ppgb was tested in mice with maternal duplication/paternal deficiency and its reciprocal for the distal region of Chr 2. We have shown by reverse transcription-polymerase chain reaction (RT-PCR) that both parental alleles of Ppgb were expressed in the brain and kidney of 17.5-day-old embryos, 18.5-day-old embryos, and newborn mice. Thus, Ppgb does not appear to be subject to imprinting effects in the mouse.

Animals↗
PubMed1994

Genetic linkage analysis of the Ak1, Col5a1, Epb7.2, Fpgs, Grp78, Pbx3, and Notch1 genes in the region of mouse chromosome 2 homologous to human chromosome 9q.

The genes for adenylate kinase-1 (AK1), folyl polyglutamate synthetase (FPGS), the collagen pro alpha 1(V) chain (COL5A1), erythrocyte protein band 7.2b (EPB72), and a proto-oncogene homeobox (PBX3) all map to the distal portion of human chromosome 9q (HSA9q) but have not previously been mapped by linking analysis in the mouse. In this study, we have used two interspecific backcrosses to map the mouse homologues of each of these genes to mouse chromosome 2 (MMU2). The Ak1, Col5a1, Epb7.2, Fpgs, and Pbx3 genes were mapped with respect to the genes for Grp78, Rxra, Notch1 (the mouse homologue of TAN1), Spna2, Abl, and Hc (the mouse homologue of C5), all of which have previously been mapped by linkage analysis on MMU2 and have human homologues that map to HSA9q. Two of the reference loci for MMU2, D2Mit1 and Acra, were also mapped in the same cross to facilitate comparisons with existing maps. The consensus gene order deduced by combining data from both crosses is D2Mit1-(Dbh,Notch1)-(Col5a1,Rxra)-Spna2-Ab l-(Ak1,Fpgs)- (Grp78,Pbx3)-(Epb7.2,Hc,Gsn)-Acra. These loci therefore form part of the conserved synteny between HSA9q and MMU2.

Animals↗
PubMed1994

Purification and characterization of a novel carbonyl reductase isolated from Rhodococcus erythropolis.

During growth on n-tetradecane a novel NADH-dependent carbonyl reductase is induced in the Gram-positive bacterium Rhodococcus erythropolis (Peters, P., Zelinski, T. and Kula, M.R. (1992) Appl. Microbiol. Biotechnol. 38, 334-340). The enzyme has been purified to homogeneity using fractional pH precipitation, anion exchange chromatography and affinity chromatography. The isoelectric point of the oxidoreductase is 4.4. The apparent molecular mass of the native enzyme is 161 kDa, that of the subunits 40 kDa as determined by SDS gel electrophoresis. A tetrameric structure of the carbonyl reductase is consistent with these results. Important biochemical data concerning the application of the reductase are: a broad pH-optimum, temperature optimum at 40 degrees C and stability at room temperature for more than 5 days. The oxidoreductase accepted as substrate aliphatic and aromatic ketones, keto esters (esters of keto carboxylic acids) and halogenated carbonyl compounds and reduced them to the corresponding hydroxyl compounds with (S)-configuration with more than 98% enantiomeric excess. The NAD(+)-dependent oxidation of primary alcohols was not catalyzed by the carbonyl reductase, whereas secondary alcohols and hydroxy acid esters were oxidized to the corresponding carbonyl compounds at about 10-fold slower reaction rates compared to the reduction.

Alcohol Oxidoreductases↗
PubMed1994

The molecular chaperone TF55. Assessment of symmetry.

TF55-like factor from Sulfolobus solfataricus was purified to homogeneity and analyzed by electron microscopy and image analysis to determine the symmetries of these particles. Three different procedures were used to analyze the electron micrographs: (1) fuzzy-set based classification of the particles according to their rotational power spectra; (2) multivariate statistical analysis based on singular value decomposition; (3) circular harmonic analysis. Averages obtained from the three methods show unequivocally that the TF55-like complex presents a 9-fold symmetry.

Archaeal Proteins↗
PubMed1994

[Acute intravasal hemolysis in Clostridium perfringens sepsis. Differential diagnosis of hemolytic episodes].

A 19-year-old man with acute lymphoblastic leukaemia developed fever, general deterioration and somnolence 3 days after a cycle of cytostatic treatment. He had anaemia (haemoglobin 6.6 g/dl), leukopenia (100/microliters) and thrombocytopenia (7,000/microliters). As an acute septicaemia was suspected he received broad spectrum antibiotic therapy, together with two units of red cell and platelet concentrates. However, his condition worsened rapidly over the next 5 hours (meningism, seizures, fever to 41.1 degrees C, dyspnoea). Another blood count revealed severe haemolysis. Computed tomography of the skull demonstrated multilocular intraparenchymal gas formation. Although the antibiotic treatment was extended the patient died several hours later. Retrospective examination for suspected transfusion mismatch provided no evidence for erythrocyte incompatibility. But there was liberation of T-antigen as sign of a bacterial cause of erythrocyte damage. An anaerobic blood culture grew Clostridium perfringens. This case demonstrates that acute intravascular haemolysis in septicaemia should be considered in the differential diagnosis of transfusion mismatch.

Adult↗
PubMed1994

Linkage mapping around the ragged (Ra) and wasted (wst) loci on distal mouse chromosome 2.

Mice that are heterozygous for the ragged (Ra) mutation, which is semidominant, have ragged coats caused by an absence of certain hair types. Ra/Ra homozygous mice usually die soon after birth, are naked, and have edema. Mice that are homozygous for the recessive mutation wasted (wst) appear normal until soon after weaning, but then develop tremors and ataxia, undergo atrophy of the thymus and spleen, and die by around 28 days of age. The Ra and wst loci map to distal mouse chromosome 2, but have never been positioned with respect to molecular markers. We have now mapped each of these genes in interspecific backcrosses that were also typed for available molecular markers. The results show that Ra maps very close to D2Mit74 and Acra-4, with no recombinants in 165 mice, whereas wst maps 3 cM distal to the most telomeric molecular marker on mouse chromosome 2, Acra-4.

Animals↗
PubMed1994

Subacute sclerosing panencephalitis in an infant: diagnostic role of viral genome analysis.

Subacute sclerosing panencephalitis (SSPE) is related to "defective" measles virus or vaccination, though an association with parainfluenza viruses has been reported. SSPE is characterized by a slow, erratic course and elevated cerebrospinal fluid measles titers. An immunocompetent, vaccinated infant, with onset of symptoms in parainfluenza virus season and a catastrophic course is described. Cerebrospinal fluid titers were negative, but postmortem brain had typical SSPE lesions. Patient brain-derived RNA, subjected to reverse transcription followed by polymerase chain reaction yielded polymerase chain reaction products with measles virus but not parainfluenza virus genes. The sequenced fragment revealed multiple mutations, typical for SSPE. SSPE can thus present in infants, with short latency and no cerebrospinal fluid antibodies. Viral genomic analysis may be diagnostic, permitting early therapy.

Antigens, Viral↗
PubMed1994

Development of an assay method for purine catabolic enzymes in the mouse and its adaptation for use on an autoanalyzer.

An assay method has been developed for the purine catabolic enzymes adenosylhomocysteinase, adenosine deaminase (ADA), purine-nucleoside phosphorylase (PNP), and urate oxidase in mice. The assay links H2O2 produced during purine catabolism to the production of a dye complex. The assay method has been developed for ADA and PNP in erythrocytes and for all four enzymes in liver. The assay is cheap, sensitive, and easy to perform. The dye complex absorbs in the visible range, negating the need for an expensive ultraviolet spectrophotometer and allowing the use of an autoanalyzer.

Adenosine Deaminase↗
PubMed1994

Mechanisms of glial swelling by arachidonic acid.

The effect of arachidonic acid (AA, 20:4) was analyzed in vitro by employment of C6 glioma cells and astrocytes from primary culture. The cells were suspended in an incubation chamber under continuous control of pH, pO2, and temperature. Cell swelling was quantified by flow cytometry. After a control period, the suspension was added with AA at concentrations of 0.01 to 1.0 mM. Administration of AA induced an immediate, dose dependent swelling in C6 glioma cells or astrocytes. AA-concentrations of 0.01 mM led to an increase of the glial cell volume to 103.0 +/- 1.0% of control, 0.1 mM to 110.0 +/- 1.5%, and 1.0 mM to 118.8 +/- 1.5% within 10 min. The swelling response to linoleic acid (18:2) was only about half of what was found when AA was administered at a concentration of 0.1 mM, whereas stearic acid (18:0) did not induce any cell volume changes. Inhibition of the cyclo- and lipoxygenase pathway by BW 755C did not prevent glial swelling from AA, whereas it was reduced by SOD, or almost completely abolished by the aminosteroid U-74389F, an antagonist of lipid peroxidation. Replacement of Na(+)- and Cl- -ions in the suspension medium by choline chloride was also associated with complete abolishment of cell swelling from AA. The results demonstrate an impressive efficacy of arachidonic acid to induce glial swelling which might be attributable to activation of lipid peroxidation by the fatty acid, leading to an increased Na(+)-permeability and subsequent influx of water into the cells.

Animals↗
PubMed1994

Shock wave treatment of salivary duct stones: substantial progress with a minilithotripter.

Extracorporeal shock wave lithotripsy has recently been introduced as the first non-operative treatment alternative for patients with sialolithiasis. Using conventional multipurpose lithotripters, however, successful treatment was achieved in only 36%-53% of patients. Therefore we developed an miniaturized lithotripter meeting the special requirements for extracorporeal shock wave treatment in the head and neck region. During a 1-year prospective trial clinical efficacy and safety were compared in 40 patients treated with a conventional electromagnetic lithotripter (group A) to 33 patients treated with the newly developed, miniaturized device (group B). The groups did not differ statistically regarding stone size or number or the proportion of stones located in the submandibular or parotid gland. Successful stone targeting, a prerequisite for shock wave treatment, was achieved by means of in-line ultrasonography in 30 of the 40 patients in group A and in 29 of 33 patients of group B. The number of shock wave impulses administered per session and the maximum shock wave intensities did not differ in the two groups. Significantly more frequent treatments with a longer mean duration of each session were required in group A (2.4 +/- 1.0 treatments, 47 +/- 11 min) than in group B (1.9 +/- 0.7 treatments, 28 +/- 9 min; P < 0.05). After a 3 month follow-up significantly more patients were free of stones in group B (22/33) than in group A (16/40; P < 0.05). Correspondingly, the number of patients free of complaints was significantly higher in group B (27/33) than in group A (22/40; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Zona glomerulosa of the adrenal gland in a transgenic strain of rat: a morphologic and functional study.

Transgenic rats for the murine Ren-2 gene display high blood pressure, low circulating levels of angiotensin II, and high renin content in the adrenal glands. Moreover, transgenic rats possess an increased aldosterone secretion (maximal from 6 to 18 weeks of age), paralleling the development of hypertension. To investigate further the cytophysiology of the adrenal glands of this strain of rats, we performed a combined morphometric and functional study of the zona glomerulosa of 10-week-old female transgenic rats. Morphometry did not reveal notable differences between zona glomerulosa cells of transgenic and age- and sex-matched Sprague-Dawley rats, with the exception of a marked accumulation of lipid droplets, in which cholesterol and cholesterol esters are stored. The volume of the lipid-droplet compartment underwent a significant decrease when transgenic rats were previously injected with angiotensin II or ACTH. Dispersed zona glomerulosa cells of transgenic rats showed a significantly higher basal aldosterone secretion, but their response to angiotensin II and ACTH was similar to that of Sprague-Dawley animals. Angiotensin II-receptor number and affinity were not dissimilar in zona glomerulosa cells of transgenic and Sprague-Dawley rats. These data suggest that the sustained stimulation of the adrenal renin-angiotensin system in transgenic animals causes an increase in the accumulation in zona glomerulosa cells of cholesterol available for steroidogenesis, as indicated by the expanded volume of the lipid-droplet compartment and the elevated basal steroidogenesis. However, the basal hyperfunction of the zona glomerulosa in transgenic animals does not appear to be coupled with an enhanced responsivity to its main secretagogues, at least in terms of aldosterone secretion.

Adrenocorticotropic Hormone↗