Biomedical subjects
Publications and source records attributed to T Köhler.
Tetrahydro-2H-benz[b]azepin-2-ones as starting substances are synthesized by Beckmann rearrangement of Schmidt reaction. The tetrahydrobenzazepinones are transformed into the thiones, thiolactim ethers and phenylhydrazones. The compounds are tested as inhibitors of soja lipoxygenase.
Changes of the number of active palmar sweat glands (palmar sweat index, PSI) as assessed by the plastic finger-print method were studied in two groups of female students (n = 21 each). In both samples experiments involved an initial adaptation period, several relaxation phases and an activation period (presentation of a movie). The film was shown 10 min earlier in Group 1, for which in turn follow-up was twice as long. Prints for determination of PSI were taken every 2.5 min from the forefinger and ring finger of the left hand, and recordings of SCL, SF (number of spontaneous fluctuations) and HR were made during the corresponding intervals. Both within- and between-groups comparisons showed an increase of PSI during the activation period and a decrease afterwards. Similar effects were observed for SCL, SF and affective and somatic arousal assessed by a state questionnaire. A decrease of PSI and parameters of electrodermal activity during the first measurements indicated an initial reaction to the assessment procedure itself. Both within-subject and between-subjects correlations between PSI from both fingers showed high parallel test reliabilities, while correlations with electrodermal variables indicated a common physiological basis.
The Pm promoter of the meta cleavage operon in the TOL (toluene degradation) plasmid pWW0 of Pseudomonas putida becomes activated by the plasmid-encoded XylS regulator in the presence of benzoate and certain substituted analogs such as 3-methylbenzoate. In the absence of XylS, Pm was still responsive to unsubstituted benzoate but with induction kinetics and a range of transcriptional activity which differed substantially from those for the XylS-mediated activation. XylS-independent induction by benzoate did not occur in a rpoN genetic background. Pm was also silent while cells were actively growing in rich medium. However, XylS-dependent transcription and XylS-independent transcription were initiated at the same nucleotide, as determined with primer extension mapping. Furthermore, a series of deletions and mutations at the Pm promoter sequence showed the same overall pattern of responsiveness to benzoate with and without XylS, thus providing genetic evidence that the same promoter structure is recognized and activated by at least two different regulators. One of them is XylS, while the other, provided by the host bacterium, could be related to the chromosome-encoded benzoate degradation pathway.
Myxococcus xanthus is a gram-negative gliding bacterium that exhibits a complex life cycle. Exposure of M. xanthus to chemicals like dimethyl sulfoxide (DMSO) at nondeleterious concentrations or the depletion of nutrients caused several negative responses by the cells. DMSO (> 0.1 M) or nutrient depletion triggered a repellent response: cell swarming was inhibited and FrzCD (a methyl-accepting chemotaxis protein) was demethylated; higher concentrations of DMSO (> 0.3 M) or prolonged starvation induced an additional response which involved cellular morphogenesis: DMSO caused cells to convert from rod-shaped vegetative cells to spherical, environmentally resistant "DMSO spores," and starvation induced myxospore formation in the fruiting bodies. In order to investigate the nature of these responses, we isolated a number of mutants defective in negative chemotaxis and/or sporulation. Characterization of these mutants indicated that negative chemotaxis plays an important role in colony swarming and in developmental aggregation. In addition, the results revealed some of the major interrelationships between the signal transduction pathways which respond to negative stimuli: (i) DMSO exposure and starvation were initially sensed by different systems, the neg system for DMSO and the stv system for starvation; (ii) the repellent response signals triggered by DMSO or starvation were then relayed by the frz signal transduction system; mutants defective in these responses showed altered FrzCD methylation patterns; and (iii) the morphogenesis signals in response to DMSO or starvation utilize a group of genes involved in sporulation (spo).
Explore the source record for details and available documents.
This study examined whether life event stress under general or more specific conditions (fear of separation, feeling of being under pressure, feeling of being caught between two quarreling parties, separation experiences) contribute to the aggravation of inflammatory bowel disease. Firstly, 51 patients with ulcerative colitis, 57 patients with Crohn's disease, and 60 controls were compared in terms of these variables. In addition, the IBD patients filled out questionnaires regarding life events, the specific psychological conditions mentioned above, and their symptoms several times in the three years after the first measurement. By means of group comparisons and intraindividual correlations between relapse precipitating life events and illness activity, only feelings of being under pressure showed a modest correlation to the disease activity. We conclude that the variables in question have little influence on the beginning of the relapse.
Myxococcus xanthus is a Gram-negative bacterium that glides on a solid surface and displays a wide range of social behaviour including microbial development. The frz genes are homologues to the chemotaxis genes of Escherichia coli and Salmonella typhimurium and have been shown to be involved in microbial development. However, chemotaxis has never been clearly demonstrated in Myxococcus. In this study, we showed that M. xanthus exhibited tactic movements to many chemicals when they were subjected to steep and stable chemical gradients. M. xanthus was observed to spread into areas with abundant nutrients like yeast extract or Casitone and avoid areas with no nutrients or repellents (short-chain alcohols or DMSO). Responses to attractants and repellents were additive. Movement towards attractants or away from repellents required the frz genes and was correlated with methylation or demethylation of FrzCD, a methyl-accepting taxis protein. Furthermore, the frz genes were found to be required for both fruiting body formation during starvation and swarming in nutrient-rich medium. In wild-type strains, cells near the colony edge were observed to swarm towards the surrounding growth medium and to contain highly methylated FrzCD; cells near the colony centre contained mainly demethylated FrzCD and showed directed movement towards the colony edge. FrzCD was also found to be methylated during the aggregation stage of fruiting body formation on agar but largely demethylated in cells shaken in liquid starvation media. An frzE mutant failed to exhibit directed cell movements and no longer showed modification of FrzCD under these conditions. These observations suggest that M. xanthus does show chemotactic movements, that these movements require the frz genes, and that chemotaxis plays a very important role in the social behaviour of this organism.
Given the contradictory results reported in the literature on the relationship between neuroticism and blood pressure, it was decided to reexamine this topic. This was done with a large sample very homogeneous for age, sex, food intake and life style and basically unselected in terms of medical history. In the frame of a blood donation program blood pressure was measured in 810 conscripts. In addition, subjects completed either form A or form B of the Eysenck Personality Inventory (EPI). Data from a total of 624 subjects were suitable for evaluation. No significant correlations were obtained between systolic or diastolic blood pressure and scores of neuroticism or extraversion (r = -0.10 to 0.06) nor did groups with different blood pressure values differ substantially in terms of these variables. This supports work showing that there is no essential connection between blood pressure and emotional lability as measured by the EPI.
3-(4-Alkylbenzoyl)acrylic acids (ABAAs) were synthesized by acylation of alkylbenzenes with maleic anhydride and then screened in vitro for inhibition of phospholipase A2 (PLA2) from snake venom and from porcine pancreas. The inhibitory potency of ABAAs increased with the length of the alkyl residues resulting in IC50 values of between 10(-7) and 10(-4) mol/L. The most potent inhibitors of the snake venom PLA2 were the 4-(n)-hexadecyl and octadecyl (OBAA) derivatives. Kinetic experiments referred to a time-dependent inhibitory reaction. Irreversibility was examined by dilution and dialysis. A molar ratio of inactivation of OBAA of nearly 20 was estimated. Double reciprocal replots of the apparent inactivation constants to the concentration of OBAA gave a (pseudo) first order rate constant of inactivation of 2.3 min-1. For the dissociation constant of the enzyme-inhibitor intermediate, a value of 6 x 10(-6) mol/L was obtained. On the other hand, the PLA2 from porcine pancreas seemed hardly to be inhibited by ABAAs. The present data are discussed in relation to the proposed model for PLA2 inactivation by manoalide. In human PMNs leukotriene B4 and 5-HETE production was essentially reduced. In human platelets the thrombin-induced TxA2 production was reduced. Since these effects disappeared after addition of arachidonic acid, these findings refer to a PLA2 inhibition. The immunologically induced bronchospasm in guinea pigs was significantly and dose-dependently inhibited by OBAA. This indicates that ABAAs might be useful in treating allergic diseases, such as asthma, eczema, allergic shock and others.
The effects of post-valve T-caecum (PVTC) cannulation and end-to-side ileo-rectal anastomosis (IRA) on growth performance, nitrogen retention and intestinal fermentation were measured in growing pigs by comparison with a control group of intact animals. There were no differences between PVTC-pigs and intact pigs in growth performance and N balance. In IRA-animals reduced growth (P < 0.01), less efficient feed conversion (P < 0.01) and decreased N retention (P < 0.001) were found. Indices of fermentation measured in ileal digesta of PVTC- and IRA-pigs were considerably different. In IRA-animals the concentration of volatile fatty acids (VFA) was about 112-162 mmol/l, higher (P < 0.001) than in digesta of PVTC-pigs (20-31 mmol/l). The molar proportions of acetate and propionate depended (P < 0.01 and P < 0.001 respectively) on the digesta-collection technique. Concentrations and ratios of VFA measured in PVTC-pigs were similar to reported values. Diaminopimelic acid (DAPA) concentration and N:DAPA ratios measured in digesta were significantly (P < 0.05 and P < 0.001 respectively) different between treatments. All digesta variables measured showed increased microbial activity in digesta of IRA-pigs; thus, an influence on digestibility measurement can be assumed.
In a long-term study nine ileo-rectally anastomosed (IRA) and seven post-valve T-caecum (PVTC)-cannulated pigs were compared with six intact pigs with regard to different blood variables, sodium and potassium retention and weights of selected organs. After surgery, apart from urea and K measured 13 weeks post-surgery, there were no differences in the blood variables between the PVTC-pigs and intact pigs. In IRA-pigs concentrations of creatinine (P < 0.01), Na (P < 0.001), base excess (P < 0.001), pH (P < 0.01) and bicarbonate (P < 0.001) in blood were lower than those in intact pigs. At 13 weeks after surgery the blood K concentration in IRA-pigs was higher (P < 0.001) than that in PVTC-pigs or intact pigs. At 6 weeks after surgery the blood urea concentration in IRA-pigs was higher (P < 0.001) than that in intact and PVTC-pigs. At 13 weeks after surgery the urea concentration in PVTC-pigs was higher (P < 0.001) than those in IRA-pigs or intact pigs. The Na (P < 0.01 11 weeks after surgery) and (P < 0.05 and P < 0.01 5 and 11 weeks after surgery respectively) balances in IRA-pigs were lower than those in intact animals. Na retention was negative for IRA-animals 11 weeks after surgery. Na and K retentions were similar in PVTC-pigs and in intact pigs. The urinary: faecal excretion of Na differed slightly between PVTC-animals and intact animals. At 13 weeks after surgery there were no differences in organ weights between the PVTC-pigs and intact animals. In the IRA-pigs the weights of the liver (P > 0.05), the kidneys (P > 0.05) and the adrenal glands were higher (P < 0.001) than those in the intact animals.
Myxococcus xanthus, a nonflagellated gliding bacterium, exhibits multicellular behavior during vegetative growth and fruiting body formation. The frizzy (frz) genes are required to control directed motility for these interactions. The frz genes encode proteins that are homologous to all of the major enteric chemotaxis proteins, with the exception of CheZ. In this study, we characterized FrzCD, a protein which is homologous to the methyl-accepting chemotaxis proteins from the enteric bacteria. FrzCD, unlike the other methyl-accepting chemotaxis proteins, was found to be localized primarily in the cytoplasmic fraction of cells. FrzCD migrates as a ladder of bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, reflecting heterogeneity due to methylation or demethylation and to deamidation. FrzCD was shown to be methylated in vivo when cells were exposed to yeast extract or Casitone and demethylated when starved in buffer. We used the methylation state of FrzCD as revealed by Western blot (immunoblot) analyses to search for stimuli that are recognized by the frz signal transduction system. Common amino acids, nucleotides, vitamins, and sugars were not recognized, but certain lipids and alcohols were recognized. For example, the saturated fatty acids capric acid and lauric acid stimulated FrzCD methylation, whereas a variety of other saturated fatty acids did not. Lauryl alcohol and lipoic acid also stimulated methylation, as did phospholipids containing lauric acid. In contrast, several short-chain alcohols, such as isoamyl alcohol, and some other solvents caused demethylation. The relatively high concentrations of the chemicals required for a response may indicate that these chemicals are not the relevant signals recognized by M. xanthus in nature. Isoamyl alcohol and isopropanol also had profound effects on the behavior of wild-type cells, causing them to reverse continuously. Cells of frzB, frzF, and frzG mutants also reversed continuously in the presence of isoamyl alcohol, whereas cells of frzA, frzCD, or frzE mutants did not. On the basis of the data presented, we propose a model for the frz signal transduction pathway in M. xanthus.
This study describes the adaptation of a filtration separation device (AK 10 from Gambro, München, FRG) and a blood monitor system (BTS 100 from Diamed, Köln, FRG) to the automated adsorption/desorption device for LDL apheresis. Plasma separation by filtration was performed by a hollow-fiber filter (OP5, Asahi Corp., Japan). In order to evaluate the quality of the plasma obtained by filtration, the platelet contamination, the activity of factors V and VIII and the concentration of the immunoglobulins IgG and IgM were determined. The following results were found: Platelet contamination of the plasma was 2,740/microliters. As compared to the patient's pretreatment values, activity of factor V was 94%, activity of factor VIII was 104%, concentration of IgG was 96%, concentration of IgM was 94%. Ten LDL aphereses were evaluated: red cell counts, platelet counts, hemoglobin concentration and hematocrit were not changed significantly. Thus, this new combination system represents an improved alternative to previously performed centrifugation methods.
Optimally adjusted anticoagulation under LDL apheresis is essential for successful treatment: Excessive anticoagulation exposes the outpatient to the risk of uncontrolled hemorrhage, insufficient anticoagulation may shorten the duration of utilization of the immune-adsorption columns. A new device (coagulation monitor 512, Ciba Corning) allows individual adaptation of dosage and timing of heparin application by modifying the standard schedule (5,000 IU intravenously before treatment, 2,000 IU/h continuously). APTT was measured before and after application of heparin and then at 30-min intervals both by the coagulation monitor and by conventional laboratory methods; the respective heparin concentration was determined in addition. The correlation coefficient between the heparin concentration and both the monitor-derived and the laboratory-derived aPTT was 0.811 and 0.590, respectively. An explanation for this finding might be that the monitor avoids the influences induced by subsequent collection and testing of samples associated with laboratory procedures.
This study examined whether life event stress under general or more specific conditions (fear of separation, feeling of being under pressure, feeling of being caught between two quarreling parties, separation experiences) contribute to the aggravation of inflammatory bowel disease (IBD). Firstly, 51 patients with ulcerative colitis, 57 patients with Crohn's disease, and 60 controls were compared in terms of these variables. In addition, the IBD patients filled out questionnaires asking for life events, the specific psychological conditions mentioned above, and their symptoms every 3 months for 1 year after the first measurement. Patients with Crohn's disease and patients with ulcerative colitis reported a lower amount of life event stress than members of the control group, but listed more feelings of being under pressure. Within group comparisons between patients in relapse and patients in remission, as well as comparisons between patients with recently increased disease activity and patients without increased disease activity did not yield clear results. We conclude that the variables in question have little influence on the beginning of a relapse.
Explore the source record for details and available documents.
Periportal (pp) or perivenous (pv) liver parenchymal cells from female adult Uje: WIST rats were isolated after retro- or antegrade digitonin infusion followed by collagenase perfusion in the opposite direction. The morphological results revealed a distinct acinar-related destruction of the pv- or pp-zone by digitonin. The remaining cells of the respective other zone showed a good structural maintenance. After subsequent conventional collagenase perfusion the yield, viability and structural integrity of the isolated hepatocytes were high. The zonal cell separation was indicated by significant differences in the pp marker glucose-6-phosphatase and the pv marker glutamine synthetase found in the isolated pp or pv cell populations. Under our experimental conditions including the use of female rats, the alanine aminotransferase and glutamate dehydrogenase as well as ethylmorphine N-demethylase and ethoxycoumarin O-deethylase activities were evenly distributed in both preparations. Under stimulating conditions the capacity for urea synthesis was similar in both pv and pp cells.
Nasal encephaloceles are rare inborn malformations of the central nervous system. We report on a 30 months old boy with recurrent bacterial meningitis where a nasal encephalocele was diagnosed. We describe diagnostic procedures and the development and treatment of this interesting disease. The nasal encephalocele was successfully removed surgically.