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P Sander

Publications and source records attributed to P Sander.

At least 55 records · Page 3Linked to original sources
PubMed1996

Correlation of molecular resistance mechanisms and phenotypic resistance levels in streptomycin-resistant Mycobacterium tuberculosis.

Quantitative susceptibility testing of clinical isolates of streptomycin-resistant Mycobacterium tuberculosis demonstrated that there is a close correlation between the molecular resistance mechanism and the in vitro activity of streptomycin: mutations in rpsL were mainly associated with high-level resistance, mutations in rrs were associated with an intermediate level of resistance, and streptomycin-resistant isolates with wild-type rpsL and rrs exhibited a low-level resistance phenotype. Investigations of streptomycin-resistant isolates with wild-type rpsL and rrs revealed that (i) there is no cross-resistance to other drugs and (ii) a permeability barrier may contribute to resistance, because resistance was significantly lowered in the presence of a membrane-active agent.

Antibiotics, Antitubercular↗
PubMed1996

Genetic basis for clarithromycin resistance among isolates of Mycobacterium chelonae and Mycobacterium abscessus.

Resistance to clarithromycin among isolates of Mycobacterium chelonae and M. abscessus was observed in 18 of 800 (2.3%) patients tested between 1990 and 1995. Patients whose isolates were resistant had either disseminated disease or chronic lung disease, and the resistant isolates were recovered after clarithromycin monotherapy. Sequencing of the gene coding for the 23S rRNA peptidyltransferase region revealed a point mutation involving adenine at position 2058 (38%) or adenine at position 2059 (62%) in 20 of 20 relapse isolates from the first 13 patients identified. By pulsed-field gel electrophoresis or random amplified polymorphic DNA PCR, initial and relapse isolates were shown to have identical DNA patterns. M. chelonae and M. abscessus isolates were found to have only a single chromosomal copy of the rRNA operon, thus making them susceptible to single-step mutations. Thus, clarithromycin resistance in these species of rapidly growing mycobacteria relates to a point mutation in the gene coding for 23S rRNA and occurs in limited clinical situations, but was identified in almost 5% of isolates tested in 1995.

Blotting, Southern↗
PubMed1996

Pharmacological and biochemical characterization of the mouse 5HT5A serotonin receptor heterologously produced in the yeast Saccharomyces cerevisiae.

The cDNA for the mouse 5HT5A receptor has been functionally expressed in the unicellular yeast Saccharomyces cerevisiae. The NH2-terminal end of the receptor gene was fused to the Bacillus macerans (1-3, 1-4)-beta-glucanase signal sequence to ensure proper membrane insertion and to the c-myc epitope to permit immunological detection of the heterologously expressed protein. In the resulting episomal yeast expression plasmid pCNNmm5HT5A the modified 5HT5A gene is under the transcriptional control of the endopeptidase B gene promoter (PRB1). After transformation of the vector into the protease deficient S. cerevisiae strain cI3-ABYS-86, recombinant clones were examined for the presence of functional receptor by radioligand binding using [3H]LSD. Whole cells as well as crude membrane preparations of recombinant clones showed saturable binding of the receptor with a KD of approximately 2.2 nM. The pharmacological properties for the heterologous expressed receptor, estimated by ligand-displacement studies using certain serotonin agonists and antagonists, were comparable to those reported for the receptor expressed in mammalian systems. Western blot analysis of membranes prepared from a recombinant clone using the monoclonal antibody 9E10, directed against the c-myc epitope of the modified receptor, revealed an apparent molecular mass of about 43 kDa for the receptor expressed in S. cerevisiae. Glycosylation of the receptor was analysed by EndoH digestion. A heat shock of recombinant yeast significantly increased the number of specific binding sites per cell and also improved the affinity of the receptor. Immunogold electron microscopy was used to study the localization of the heterologously expressed protein within the yeast cells.

Amino Acid Sequence↗
PubMed1996

Minimal care--a new concept for the management of urinary incontinence in an open access, interdisciplinary incontinence clinic. The way ahead?

A new concept for assessment and treatment of urinary incontinence in an open access, interdisciplinary clinic is evaluated prospectively. Based on the patients needs and expectations, a minimal relevant investigative programme was planned. The patients were primarily offered conservative, non-surgical treatment modalities with a limited consumption of resources. The reference programme for investigation and treatment is referred to as the "minimal care principle". We here report our results in the first 300 women and 27 men consecutively investigated and created in the clinic. Ninety percent of the patients were managed by conservative treatment modalities whereas only 10% of the patients were referred to in-hospital treatment with invasive treatment modalities, mainly surgical procedures for urinary incontinence. Subjectively, 68% felt cured or very much improved, 23% experienced improvement and 9% did not report benefit of the treatment. Objectively, significantly diminished leakage of urine could be demonstrated in 71% of the patients by the pad weighing test. Our results demonstrate that an open access, interdisciplinary clinic is well accepted by the patients and effective for the evaluation and treatment of urinary incontinence.

Adolescent↗
PubMed1995

rpsL+: a dominant selectable marker for gene replacement in mycobacteria.

Molecular genetic manipulations in mycobacteria would benefit from procedures which efficiently select for double-crossover events by homologous recombination. Here we describe a vector-host system for gene replacement in mycobacteria, the utility of which was investigated using functional inactivation of the pyrF gene in Mycobacterium smegmatis as a model. This system is based on the expression of the wild-type rpsL gene coding for ribosomal protein S12 in a streptomycin-resistant host. Owing to the absence of a mycobacterial origin the plasmids are unable to replicate autonomously in mycobacteria. The first selection for maintenance of cloned sequences is conferred by the kanamycin-resistance gene. The second simultaneous selection by streptomycin is against maintenance of cloned sequences which contain the gene encoding the streptomycin-sensitive allele of the rpsL gene. By placing the gene for positive selection and that used for negative selection within and outside the target gene of interest, respectively, gene replacement is obtained. A one-step double selection procedure provides a means to distinguish strictly between gene replacement by double crossover versus homologous recombination by single crossover events. The system should have considerable potential for genera or species where single-crossover events or even illegitimate recombination are the predominant recombination mechanisms. It should also be of wide use for the construction of mutants without a selectable phenotype.

Base Sequence↗
PubMed1994

Heterologous expression of the human D2S dopamine receptor in protease-deficient Saccharomyces cerevisiae strains.

The cDNA for the human D2S dopamine receptor has been functionally expressed in the unicellular yeast Saccharomyces cerevisiae. The original D2S gene and an elongated D2S gene with an N-terminal fusion to the first 24 amino acids of the STE2 gene from S. cerevisiae were introduced into the episomal yeast expression vector YEp51 under the control of the GAL10 promoter. Expression studies performed in a wild-type strain and in two protease-deficient strains of S. cerevisiae revealed that the receptor was functionally expressed with respect to its ligand-binding properties. The KD values for the binding of the dopamine antagonist [3H]spiperone were calculated to be 1.6 nM for the D2S receptor alone and 1.9 nM for the STE2-D2S chimaera. Both membrane proteins could be further characterized by ligand-displacement studies using certain dopamine agonists and antagonists. D2S dopamine-receptor-specific polyclonal antibodies were used to monitor the heterologous expression of the receptor. Western-blot analysis of membranes prepared from transformed yeast cells producing either the receptor protein alone or the receptor fusion protein revealed apparent molecular masses of 40 kDa (D2S receptor alone) and 42 kDa (STE2/D2S receptor fusion protein). It could be shown that, in comparison to the expression in a wild-type S. cerevisiae strain, the amount of receptor degradation was drastically reduced in the protease-deficient strains. The localizations of the heterologously produced dopamine receptor and of the chimaera in the recombinant yeast were studied by immunogold electron microscopy and were found to be restricted mainly to the vacuole of the cells.

Base Sequence↗
PubMed1994

Constitutive expression of the human D2S-dopamine receptor in the unicellular yeast Saccharomyces cerevisiae.

The cDNA for the human D2S-dopamine receptor has been functionally expressed in the unicellular yeast Saccharomyces cerevisiae. Two expression plasmids pRS421D2 (original D2S-gene coding region) and pRS421D2S (the first 24 aa of the yeast STE2-gene are fused to the N-terminus of the D2S-gene) were constructed and transformed into the protease deficient S. cerevisiae strain cI3-ABYS-86. Northern blot analysis of total RNA from transformed yeast clones revealed that for both constructs the D2S-gene was constitutively transcribed from the plasmids PMA1 promoter. Membranes prepared from recombinant S. cerevisiae exhibited saturable binding with the antagonist [3H]methylspiperone. Competition studies revealed pharmacological properties for these sites which were comparable to those reported for the D2-receptor heterologously expressed in mammalian cells. The expression of the receptor was monitored by Western blot analysis using an antiserum raised against a peptide from the third intracellular domain of the receptor protein and by ligand binding assay.

Amino Acid Sequence↗
PubMed1994

Expression of the human D2S dopamine receptor in the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe: a comparative study.

The yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe were tested for heterologous expression of the human D2S dopamine receptor. The cDNA coding for the dopamine receptor was cloned into high copy number plasmids with inducible promoters. After transformation into the yeasts recombinant clones were examined for the presence of functional receptor by radioligand binding using the antagonist [3H]spiperone. Subsequent Western blot analysis of positive recombinants with an antiserum raised against a peptide from the third intracellular domain of the receptor protein revealed the production of a protein with an apparent molecular mass of 40 kDa in both yeasts. Membranes harvested from recombinant yeast clones exhibited saturable binding of the dopaminergic antagonist [3H]spiperone with Kd values of 1.3 nM in S. cerevisiae and 0.25 nM in S. pombe. The rank order of potencies for several dopaminergic ligands to displace specific [3H]spiperone binding to membranes were the same in both yeasts, whereas the affinities for ligands differed significantly.

Binding Sites↗
PubMed1994

Orally administered N-acetylcysteine may improve general well-being in patients with mild chronic bronchitis.

Oral N-acetylcysteine (NAC) exerts a beneficial action in chronic bronchitis by reducing the number of exacerbations. There have been few studies of the effect of NAC (or of any other drug) on general well-being in chronic bronchitis. We used an established psychiatric instrument (General Health Questionnaire; GHQ) and a visual analogue scale (VAS) to measure well-being in a 22-week, placebo-controlled, double-blind, parallel-group study of NAC administered as sustained release tablets 600 mg b.i.d., including during the winter months, to patients with mild chronic bronchitis. One hundred and fifty-three patients were accepted for randomized treatment, 129 finished the study (59 NAC, 70 placebo), and well-being was measured in 105 (46 NAC, 59 placebo). The number of observed exacerbations was unexpectedly low in both groups. The number was lowest in the NAC group, however, the difference did not reach statistical significance in the present study (P = 0.08). There were no statistically significant differences between NAC and placebo in subjective symptom scores, FEV1 or FVC. The distribution of GHQ score at baseline was uneven, but NAC was significantly superior to placebo in terms of a favourable effect on GHQ score. GHQ score correlated with the number of exacerbations, and VAS correlated with GHQ score. This study therefore demonstrates the validity of measuring general well-being in patients with mild chronic bronchitis. Future studies of the treatment of chronic bronchitis should use a battery of more specifically adapted instruments which are now becoming available to measure well-being.

Acetylcysteine↗
PubMed1994

Mast cells in the placenta. Is there a relation to the development of atopic disease in infants before 18 months of age?

OBJECTIVE: To disclose a relation between the amount of mast cells in placenta and the development of atopic disease in children before 18 months of age. DESIGN: A prospective, descriptive study. SETTING: Two obstetric departments at university hospitals. SUBJECTS: 67 pairs of mothers and their newborn infants. MAIN OUTCOME MEASURES: Family history of atopic disease was taken. The amount of mast cells in placenta was counted. Follow-up questionnaires of the children were evaluated after 18 months. RESULTS: The follow-up rate was 84%. The number of mast cells in placenta did not differ between atopic and non-atopic children. CONCLUSION: A new predictor, the amount of mast cells in placenta was evaluated. In this study the amount of mast cells, in placenta was not predictive of the development of atopic disease before 18 months of age.

Cell Count↗
PubMed1993

Mechanisms of upstream activation of the rrnD promoter P1 of Escherichia coli.

The rrn promoter regions of Escherichia coli contain a stretch of DNA, rich in An and Tn homopolymer sequences, which is located upstream of the tandem promoters P1 and P2. We have studied the effects of the upstream sequence of the rrnD operon on promoter function, using deletion variants for in vitro transcription. The presence of the upstream activating sequence (UAS) was found to increase P1 promoter strength without influencing P2. Two modes of P1 activation could be distinguished: a stimulation of P1 depending on the interaction of the factor of inversion stimulation (FIS) with the UAS (within the deletion boundaries of -50 and -112) and second, a factor-independent activation requiring the proximal part of the UAS (within the boundaries of -50 and -89). Both modes of activation were previously observed in the case of the rrnB operon and were ascribed to increased constants of RNA polymerase binding to P1 (Leirmo, S., and Gourse, R. L. (1991) J. Mol. Biol. 220, 555-568; Zacharias, M., Theissen, G., Bradaczek, C., and Wagner, R. (1991) Biochimie 73, 699-712). Our results show, however, that the mechanisms of upstream activation may vary with the reaction conditions. In a complex transcription system, originally designed for the use of cell extracts, FIS enhances first-order reactions that convert binary (open) complexes to transcribing complexes. Initiated complexes are stabilized by FIS. The factor-independent mode of P1 activation involves influences of the UAS on complex isomerizations as well as on binary complex formation. The results show that low molecular weight components of the complex transcription system change the function of the RNA polymerase at the rrn promoters (not at the reference promoter Ptac), so that the conversion of open to transcribing P1-complexes becomes dependent on the UAS and FIS.

Base Sequence↗
PubMed1991

Degradation of 1,2,4-trichloro- and 1,2,4,5-tetrachlorobenzene by pseudomonas strains.

Two Pseudomonas sp. strains, capable of growth on chlorinated benzenes as the sole source of carbon and energy, were isolated by selective enrichment from soil samples of an industrial waste deposit. Strain PS12 grew on monochlorobenzene, all three isomeric dichlorobenzenes, and 1,2,4-trichlorobenzene (1,2,4-TCB). Strain PS14 additionally used 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB). During growth on these compounds both strains released stoichiometric amounts of chloride ions. The first steps of the catabolism of 1,2,4-TCB and 1,2,4,5-TeCB proceeded via dioxygenation of the aromatic nuclei and furnished 3,4,6-trichlorocatechol. The intermediary cis-3,4,6-trichloro-1,2-dihydroxycyclohexa-3,5-diene (TCB dihydrodiol) formed from 1,2,4-TCB was rearomatized by an NAD-dependent dihydrodiol dehydrogenase activity, while in the case of 1,2,4,5-TeCB oxidation the catechol was obviously produced by spontaneous elimination of hydrogen chloride from the initially formed 1,3,4,6-tetrachloro-1,2-dihydroxycyclohexa-3,5-diene. Subsequent ortho cleavage was catalyzed by a type II catechol 1,2-dioxygenase producing the corresponding 2,3,5-trichloromuconate which was channeled into the tricarboxylic acid pathway via an ordinary degradation sequence, which in the present case included 2-chloro-3-oxoadipate. From the structure-related compound 2,4,5-trichloronitrobenzene the nitro group was released as nitrite, leaving the above metabolite as 3,4,6-trichlorocatechol. Enzyme activities for the oxidation of chlorobenzenes and halogenated metabolites were induced by both strains during growth on these haloaromatics and, to a considerable extent, during growth of strain PS12 on acetate.

Journal Article↗
PubMed1989

[Infection-associated hemophagocytic syndrome with a lethal outcome].

A 53-year-old man fell ill with myalgia, an haemorrhagic diathesis, fever, renal failure and circulatory shock. Anaemia, thrombocytopenia and lymphadenopathy quickly developed, and he died after 13 days of bronchopneumonia in treatment-resistant cardiocirculatory failure. The underlying cause of the illness, in the two weeks during which he received intensive treatment with prolonged mechanical ventilation, haemodialysis, administration of clotting factors and blood derivatives as well as high doses of cortisone and antibiotics, remained uncertain. Histological examination of lymph-node biopsy and bone-marrow obtained at autopsy demonstrated massive increase in the number of benign haemophagocytic histiocytes, which--together with the clinical picture--gave the diagnosis of an infection-associated haemophagocytic syndrome. This is a rare disease and apparently the expression of an abnormal immune reaction with potentially reversible phagocytosis of the body's own blood cells after preceding infection, often a viral one.

Acute Kidney Injury↗
PubMed1987

[Amyloid tumor of bone].

An osseous plasmocytoma was masked by an excessive tumor-like deposit of amyloid to such an extent that the primary disease was only diagnosed after histological examination of autopsy material from a 62 year old woman. The 20 cm in diameter tumor originated from the manubrium sterni. Other tumors were found in the ribs, right clavicle, thoracic and lumbal spine and in the left femur. A massive layer of amyloid was found in these tumors by microscopy. Plasma cells infiltrated the area between the amyloid plaques and the macroscopically tumor-free vertebral bodies. All other organs were free from amyloid.

Amyloidosis↗
PubMed1983

[Angioimmunoblastic lymphadenopathy. Diagnosis and differential diagnosis].

On the basis of 8 biopsy and 3 autopsy cases of the Pathological Department, Schwerin County Hospital and of 4 selected biopsy and autopsy cases of the Department of Pathology, Medical University of Pécs, the pathomorphological diagnosis and differential diagnosis of angioimmunoblastic lymphadenopathy (AIBLP) or lymphogranulomatosis X are discussed. Borderline lesions between common reactive changes and AIBLP are high-grade paracortical hyperplasia and the so-called angioimmunoblastic reaction (AIBR) which may be associated with a partial transformation of lymph node structure. On the other hand, AIBLP should be differentiated from malignant lymphomas (immunoblastoma, T-zone lymphoma, Hodgkin's disease). The polyclonality of plasma cells, the presence of mature lymphocytes in higher numbers, the low mitotic rate, the absence of atypical giant cells all speak for AIBLP. AIBLP can be subdivided into several types (immunoblast-rich, plasma cell-rich, mixed cell type, epitheloid cell-rich type and lymphocyte-rich type. Lennert et al. 1979), the prognostic relevance of which should be assessed on a large number of cases.

Autopsy↗