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Biomedical subjects

M Wagner

Publications and source records attributed to M Wagner.

At least 523 records · Page 29Linked to original sources
PubMed1993

Migration and marriage in the life course: a method for studying synchronized events.

"On the basis of a West German sample of residence histories that is representative of three birth cohorts, of which the one born in 1939-41 is analysed, log-linear techniques were applied to separate the effects of being married, and of getting married, on migration rates. Results show that the dependence of short and long distance moves on age substantially [diminishes] if marriage is considered as a synchronization variable. Moreover, the common finding that married persons move less than the unmarried is reversed at short distances if marriage is taken into account as an event which influences the probability of another (event dependence)." (SUMMARY IN FRE)

Age Factors↗
PubMed1993

3H-spiperone binding to lymphocytes fails in the differential diagnosis of de novo Parkinson syndromes.

In order to investigate the diagnostic value of 3H-spiperone binding capacity to lymphocytes in the differential diagnosis of de novo Parkinson's disease (idiopathic Parkinson syndrome, PD), we performed a double blind prospective study of spiperone binding capacity of 123 patients and 23 healthy control persons, belonging to different diagnostic groups (PD, Parkinsonian syndrome due to vascular lesions, multiple system atrophy [MSA], essential tremor). Diagnoses were based on medical history, clinical examination, CT or MRI scan, acute response to dopamimetic drugs, one year follow up, and long term response to L-DOPA treatment. Spiperone binding was assayed using ten different concentrations (0.03-3 nmol) in absence or presence of 1 mumol (+)-butaclamol to determine nonspecific binding. There was no significant difference in spiperone binding between patients with PD not treated with L-DOPA, and patients with other basal ganglia disorders including parkinsonian syndrome due to vascular lesions, multiple system atrophy, or progressive supranuclear palsy, and age matched controls. Binding was significantly higher in parkinsonian patients with PD treated with L-DOPA and patients with essential tremor. It is concluded that at present 3H-spiperone binding gives no further information in the differential diagnosis of de novo Parkinson's disease.

Adult↗
PubMed1993

"Probing" the nature of the CNV.

A widespread depolarization in the dendritic trees of cortical pyramidal neurons generates surface-negative potentials. In turn, such potentials may indicate facilitatory processes, while positive-going waves may result from a lowering in cortical excitability. Accordingly, we may expect the processing of "probe" stimuli presented during surface-positive waves, i.e., during phases of lesser excitability, to be inhibited and probes presented during surface-negative waves to be facilitated. This hypothesis was tested by presenting acoustic probe stimuli at various points in time during a forewarned reaction time task. The warning stimulus (WS) elicited a late positive complex followed by a negative slow potential shift (CNV). In 75% of the total of 120 trials a probe could be presented 1.5 sec prior to the WS interval, 0.5, 1, 1.5 or 2 sec after the onset of the 3 sec visual WS, and 3 sec following the imperative signal (WS offset, requiring a fast button press response), while 25% of the trials were without any probe. Only one probe occurred during a trial. The EEG was recorded along the midsagittal line; responses to the probes were evaluated by reaction time (RT) and probe-evoked potentials. RT to probes presented late in the anticipatory interval were speeded up and probe-evoked potentials were enhanced during this interval, in parallel to the development of the slow potential and the CNV in particular. Results suggest that probe stimuli presented during the development of the CNV were processed more intensely, thereby supporting the hypothesis that slow cortical potentials indicate the timing of excitability in cortical neuronal networks.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1993

[Anesthesia in familial hyperkalemic periodic paralysis].

A 53-year-old woman was scheduled for elective surgery of a L4-L5 lumbar disc prolapse. Preoperatively, she reported of a hereditary muscle disease in her family which could be identified as familial hyperkalaemic periodic paralysis. In patients with familial periodic paralysis, only limited information is available in the current anaesthesiological literature. This is especially true of the hyperkalaemic form which was separated from the hypokalaemic form in 1957. Most patients suffering from periodic paralysis will develop myotonic symptoms in time, but evidence is lacking that the incidence of malignant hyperthermia (MH) is higher than in normals. However, abnormalities of the electrocardiogram (ECG) due to changes in the potassium serum levels are not unusual, and the anaesthesiologist must be aware of cardiac arrhythmias. In the present case, the patient was anaesthetized using fentanyl, midazolam, and vecuronium, and ventilated with 66% nitrous oxide in oxygen. Radial artery blood pressure, end-tidal CO2, and nasopharyngeal temperature were monitored continuously. Surgery was completed after 2 hours with no abnormalities in the intraoperative course. Recovery from anaesthesia was uneventful. During the postoperative follow-up for 1 week, further attacks of paralysis, intermittent sodium-potassium imbalance of the muscle cell membrane appears to be the primary pathogenetic factor. In this special disease, prevention of carbohydrate depletion and the avoidance of muscle relaxants are recommended in the anaesthesiological literature. However, a specified regimen of general anaesthesia has not yet been outlined. In our special case, the use of anaesthetics deemed to be safe in MH susceptible patients produced an uneventful perioperative course.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1993

Inhibition of melanoma cell/matrix interaction by tamoxifen.

Following our recent finding that calmodulin antagonists can reduce cancer cell attachment to extracellular matrix proteins, we investigated the calmodulin antagonistic and anti-attachment properties of the non-steroidal anti-oestrogens tamoxifen and droloxifene. These drugs and four of their active metabolites were found to have calmodulin antagonist activity with IC50 values of 2-4 microM and to be capable of inhibiting attachment of murine B16 melanoma to extracellular matrix proteins in vitro. IC50 values for inhibition of attachment were 11 microM for tamoxifen and ranged from 5 to 40 microM for the other five compounds tested. (Poor reproducibility in drug potency between attachment experiments was almost certainly due to the low aqueous solubility of these drugs.) The effects of tamoxifen on cell/matrix adhesion were most evident between 15 min and 3 h of cell attachment. No effects of tamoxifen were evident in cells which had been allowed to attach for 6 h or more. Tamoxifen at concentrations between 0.1 and 30 microM was without effect on intracellular free calcium concentration. Tamoxifen also inhibited attachment of human ocular melanoma cells and human breast cancer (MCF7) cells to type I collagen. The concentration at which tamoxifen and its metabolites affect cell attachment in vitro (2-14 microM) is of the same order as the tissue concentrations of these drugs achieved clinically. The possibility exists that reduction of cell/matrix interactions may contribute to the clinical anti-metastatic efficacy of tamoxifen and some of its active metabolites.

Animals↗
PubMed1993

Probing activated sludge with oligonucleotides specific for proteobacteria: inadequacy of culture-dependent methods for describing microbial community structure.

Bacterial community structures in activated sludge samples from aeration tanks of a two-stage system with a high-load first stage and a low-load second stage were analyzed with oligonucleotide probes. The probes were complementary to conserved regions of the rRNA of the alpha, beta, and gamma subclasses of proteobacteria and of all bacteria. Group-specific cell counts were determined by in situ hybridization with fluorescent probe derivatives. Contributions of the proteobacterial subclasses to total bacterial rRNA were quantified by dot blot hybridization with digoxigenin-labeled oligonucleotides. The activated sludge samples were dominated by proteobacteria from the alpha, beta, or gamma subclass. These proteobacteria account for about 80% of all active bacteria found in the activated sludge. For both samples the community structures determined with molecular techniques were compared with the composition of the heterotrophic saprophyte flora isolated on nutrient-rich medium. Probes were used to rapidly classify the isolates and to directly monitor population shifts in nutrient-amended, activated sludge samples. The rich medium favored growth of gamma-subclass proteobacteria (e.g., enterobacteria) and selected against beta-subclass proteobacteria. The culture-dependent community structure analysis of activated sludge produced partial and heavily biased results. A more realistic view will be obtained by using in situ techniques.

Bacteria↗
PubMed1993

Immunochemistry of capsular type polysaccharide and virulence properties of type VI Streptococcus agalactiae (group B streptococci).

The immunochemistry of capsular type polysaccharide and virulence characteristics of group B streptococci (GBS), type VI, were studied. By high-pressure anion-exchange chromatography and pulsed amperometric detection, as well as by 13C nuclear magnetic resonance analysis, both extracellular and cell-bound polysaccharides were found to contain glucose, galactose, and N-acetylneuraminic acid in the molar ratio of 2:2:1, respectively. At variance with all other GBS serotypes described to date (Ia, Ib, II, III, IV, and V), no N-acetylglucosamine was present, whatever the source of the material (secreted or cell bound; reference or clinical isolate). Sialic acid was probably involved in the immunodeterminant structure of this new serotype since cleavage of this sugar from the polysaccharide gave rise to an antigen which reacted very weakly with type VI antiserum and to a precipitation line in immunodiffusion with no identity with the native type VI polysaccharide. By using type VI antiserum and the protein A-gold technique, a large capsule was observed in the type VI GBS reference strain by electron microscopy. All type VI strains examined were lethal for CD-1 mice, the 50% lethal dose after intraperitoneal challenge ranging from 1.0 (+/- 0.9, standard deviation) x 10(5) to 2.5 (+/- 1.5, standard deviation) x 10(5) CFU per mouse. A rabbit antiserum against capsular type polysaccharide exhibited both protective activity for mice injected intraperitoneally with type VI reference strain or with clinical isolates and opsonic activity in a phagocytosis assay.

Acetylglucosamine↗
PubMed1993

[Adrenal cortical tumors. Prognostic evaluation of a series of 12 cases using anti-PCNA antibodies].

Adrenocortical tumors malignancy may be difficult to assess by morphological data. Twelve cases of such tumors were reviewed and classified benign (group I) or malignant (group II) according to follow yp. Using a peroxidase antiperoxidase method, nuclear affinity for anti-PCNA antibody was studied. The percentage of positive nuclei is significantly different in both groups: the mean value is 1.025% in benign tumors (range from 0.40 to 3.02%) and 16.765% (range from 5.62 to 31.40%) in malignant tumors (p < 0.01 according to Mann and Whitney U test). Although our study group is rather small, it suggests that analysis of nuclear affinity for PCNA could be helpful in assessment of adrenocortical tumors malignancy.

Adrenal Cortex Neoplasms↗
PubMed1993

[Adrenocortical tumors. I. Prognostic evaluation of a series of 17 cases using the Weiss criteria].

Weiss proposed 9 histologic criteria to evaluate the malignancy of adrenal cortical tumors. Each tumor is graded from 0 to 9 according to how many of the criteria are present. Eight of the 17 neoplasms from the present study were graded from 0 to 2; none of these 8 tumors metastasized or recurred. The grade of the nine other neoplasms ranged from 3 to 8; seven lesions metastasized (grade 4 to 8), one recurred (grade 5), and the last one neither metastasized nor recurred (grade 3) although this tumor was considered malignant according to Weiss' system. Even thought the results obtained using Weiss' system are similar to the results that were put forwards initially, and despite prognostic uncertainty with grade 3 tumors, we think that the later system provides a more objective evaluation of the prognosis of adrenal cortical tumors, compared with usual morphologic methods.

Adrenal Cortex Neoplasms↗
PubMed1993

Interrelations between electrical and biochemical processes in ischemic porcine livers at low temperature.

Recently it has been shown that during liver ischemia at 25 degrees C the presence of glycogen, by supporting glycolytic supply, not only retards ATP decay but also leads to a corresponding delay of the rise of the electrical impedance of the ischemic organ. A sudden rise of impedance during ischemia is supposed to indicate the closure of gap junctions. Although similar effects on energy state do exist at low temperature, the impact of glycogen on the electrical impedance under storage conditions has still to be evaluated. Therefore, in a model with protected porcine livers, we examined the intraischemic effects of a preischemic glucose and potassium feeding on impedance changes, lactate production and ATP-content at a storing temperature of 5 degrees C. Impedance was measured both in the low frequency alpha- and the higher frequency beta-dispersion range. In addition, the same parameters were determined in a group of unprotected livers. In this group all animals had received glucose and potassium orally prior to ischemia. Whereas in case of preischemic glucose feeding the rise of impedance in the range of the beta-dispersion (e.g. 5kHz) roughly coincided with the exhaustion of ATP, the corresponding impedance changes in the protected group without a glucose premedication only occurred when glycolysis had already stopped and ATP had reached basal values for some hours. In contrast, in the alpha-dispersion range the impedance changes in the latter group just began at the time when ATP became exhausted and lactate production ceased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗