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Biomedical subjects

F Schneider

Publications and source records attributed to F Schneider.

At least 109 records · Page 6Linked to original sources
PubMed2000

Neuromonitoring and neurocognitive outcome in off-pump versus conventional coronary bypass operation.

BACKGROUND: Cardiopulmonary bypass seems to be a major cause for both intraoperative microemboli and cerebral hypoperfusion. This study investigates high intensive transient signals (HITS) in transcranial Doppler ultrasound (TCD) and serum levels of the neurobiochemical marker protein S-100 in patients who underwent coronary artery bypass operation without cardiopulmonary bypass (off-pump CABG) in comparison with the conventional procedure using cardiopulmonary bypass (CPB). The results are related to the neuropsychologic outcome in both surgical groups. METHODS: Forty patients were randomized in 2 groups (20 conventional and 20 off-pump CABG). Neurocognitive status was assessed preoperatively and postoperatively. Venous serum levels of S-100 protein were measured before and after coronary operation, HITS were measured in the middle cerebral artery during the operation. RESULTS: The median value of HITS was 394.5 (0 to 2217) in the conventional versus 11 (0 to 50) in the off-pump group, p less than 0.0001. Postoperative S-100 serum levels were: 3.76 (0.13 to 11.2) microg/L (conventional) versus 0.13 (0.04 to 1.01) microg/L (off-pump), p less than 0.0001. Postoperative cognitive testing showed significantly different results with a postoperative impairment of 90% of the patients in the conventional group versus no impairment in the off-pump group. CONCLUSIONS: Cognitive impairment seems to be strongly associated to CPB and the occurrence of micro-emboli. The off-pump technique appears to be promising in order to eliminate the source of these neuropyschologic impairments following CABG operation.

Cardiopulmonary Bypass↗
PubMed2000

Evaluation of different measles IgG assays based on recombinant proteins using a panel of low-titre sera.

During the WHO campaign to eradicate measles, accurate discrimination between immune and non-immune individuals will become increasingly important. Due to waning immunity in vaccinated populations, the performance of a measles IgG assay depends mainly on its ability to detect reliably seronegative individuals among many vaccinees with low antibody levels. New serological tests based on recombinant proteins detect only a fraction of the total measles virus (MV) specific antibodies. Therefore, several assays based on recombinant MV-haemagglutinin (ELISA and flow cytometry) or MV-fusion protein (flow cytometry) as well as neutralisatlon and haemagglutination test have been evaluated using a large panel of low-titre and negative sera. Since such an evaluation is highly dependent on threshold values for positivity, the receiver operating characteristic curve analysis was applied. The H-FACS and the H-ELISA showed the best performing characteristics (specificity: 97.4 and 96.1%, respectively; sensitivity: 88.1 and 89.6%, respectively) and may be an alternative to the neutralisation assay. The number of undefined/grey zone sera was significantly lower compared to a commercial whole virus-based ELISA and therefore fewer individuals would be vaccinated unnecessarily.

Antibodies, Viral↗
PubMed2000

Effects of Lactobacillus amylovorus and Bifidobacterium breve on cholesterol.

To determine the validity of the hypothesis of assimilation and/or precipitation of cholesterol by Lactobacillus and Bifidobacterium species, culture were undertaken in TPY medium containing oxgall or taurocholic acid. In the case of growing cells, both strains were able to remove cholesterol in the presence of bile salts. Nevertheless, the behaviour was different according to the kind of bile salt. In the presence of taurocholic acid, the removal of cholesterol was due to both bacterial uptake and precipitation. In the presence of Oxgall, bacterial uptake and precipitation were observed for Lactobacillus but only precipitation occurred for Bifidobacterium.

Bifidobacterium↗
PubMed2000

Effects of fructooligosaccharides and their monomeric components on bile salt resistance in three species of bifidobacteria.

The influence of fructooligosaccharides (FOS) and their monomeric components on bile salt resistance of Bifidobacterium breve ATCC 15700, Bif. longum ATCC 15707 and Bif. animalis ATCC 25527 was examined. The neosugars induced fructofuranosidase activities for the degradation of these saccharides. For the three strains tested the growth was identical and bile salts had the same inhibitory effect on growth whatever the carbohydrate used. The survival of Bif. breve and Bif. longum, in the presence of glycodeoxycholic acid depended, however, on carbohydrates: the toxic effects of the bile salt could be partly alleviated by the addition of a metabolizable C-source. For Bif. animalis, the presence of any carbohydrate in the incubation medium did not enhance the viability of the strain. But in the three deconjugating strains of bifidobacteria studied, the presence of neosugar during the growth led to improved resistance to the bactericidal effect of the bile salt compared with the monomeric components of these neosugars (glucose and fructose).

Animals↗
PubMed2000

Isolation and characterization of a Lactobacillus amylovorus mutant depleted in conjugated bile salt hydrolase activity: relation between activity and bile salt resistance.

Growth experiments were conducted on Lactobacillus amylovorus DN-112 053 in batch culture, with or without pH regulation. Conjugated bile salt hydrolase (CBSH) activity was examined as a function of culture growth. The CBSH activity increased during growth but its course depended on bile salts type and culture conditions. A Lact. amylovorus mutant was isolated from the wild-type strain of Lact. amylovorus DN-112 053 after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. An agar plate assay was used to detect mutants without CBSH activity. In resting cell experiments, the strain showed reduced activity. Differences between growth parameters determined for wild-type and mutant strains were not detected. Comparative native gel electrophoresis followed by CBSH activity staining demonstrated the loss of proteins harbouring this activity in the mutant. Four protein bands corresponding to CBSH were observed in the wild-type strain but only one was detected in the mutant. The specific growth rate of the mutant strain was affected more by bile salts than the wild-type strain. Nevertheless, bile was more toxic for the wild-type strain. In viability studies in the presence of nutrients, it was demonstrated that glycodeoxycholic acid exerted a higher toxicity than taurodeoxycholic acid in a pH-dependent manner. No difference was apparent between the two strains. In the absence of nutrients, the wild-type strain died after 2 h whereas no effect was observed for the mutant. The de-energization experiments performed using the ionophores nigericin and valinomycin suggested that the chemical potential of protons (ZDeltapH) was involved in Lactobacillus bile salt resistance.

Amidohydrolases↗
PubMed2000

[Improvement of agitation and anxiety in dementia patients after psychoeducative training of their caregivers].

It has been convincingly demonstrated that in dementia psycho-educative training of caregivers positively impacts on motivation for care and satisfaction of the caregivers. It has, however, been neglected to examine the effect of psycho-educative training on the behavioural and psychological symptoms of dementia sufferers. In a three-month, expert-based and conceptualized group intervention with caregiving relatives of demented patients we investigated, whether functional impairment and behavioural and psychological symptoms may improve, which of a set of independent variables may predict improvement, and how the group intervention will be appreciated by the caregivers. The group intervention yielded a significant improvement of memory-related functions in daily living and a significant decrease of agitation and anxiety of the demented patients. The presence of an additional somatic disease predicted worse outcome of the intervention with respect to the impairment of memory-related functions in daily living and of agitation. Anonymous inquiry of the caregivers with respect to their judgement of the intervention revealed high acceptance and appreciation. This study demonstrated that a psycho-educative group intervention with caregiving relatives of dementia sufferers is helpful for both the caregivers and the demented patient. This evidence of a positive mediate effect of the group intervention on the functional and behavioural impairment of the demented patients underscores the importance of nonpharmacological strategies in the treatment plan of dementia.

Aged↗
PubMed2000

Favorable outcome in a large left heart air embolism: lessons from an unusual complication of a noninvasive chest scan.

OBJECTIVE: To report an unusual life-threatening complication of the performance of a computed tomographic (CT) scan of the chest. DESIGN: Case report. SETTING: University hospital. PATIENT: An intubated patient with blunt thoracic trauma. INTERVENTION: Performance of a CT scan of the chest at full inspiration. MAIN RESULT: With air insufflation, a large left ventricular air embolism occurred as a consequence of an airway breach, revealed by the simultaneous existence of a mild bilateral anterior pneumothorax. CONCLUSION: CT scan of the chest in patients at risk of airway breach (patients with acute respiratory distress syndrome, trauma patients) should first be performed at full expiration, not full inspiration.

Accidents, Traffic↗
PubMed2000

Prevalence and characteristics of multinucleoside-resistant human immunodeficiency virus type 1 among European patients receiving combinations of nucleoside analogues.

The prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n = 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1. 6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.

Amino Acid Substitution↗
PubMed2000

Bile salt toxicity to some bifidobacteria strains: role of conjugated bile salt hydrolase and pH.

The purpose of this work was to study some aspects of bile salt toxicity towards bifidobacteria. A strain (Bifidobacterium coryneforme ATCC 25911) was selected for its lack of conjugated bile salt hydrolase activity (CBSH-), and was used with three deconjugating strains (CBSH+), for study of their growth and viability in the presence of two dihydroxylated conjugated bile salts (tauro- and glyco-deoxycholic acids). The presence of the glycoconjugate induced a more significant growth inhibition for the four strains than the tauroconjugate. The viability of the strains was measured at several pH levels. Glycodeoxycholic acid, but not taurodeoxycholic acid, exerted a lethal effect, which increased at low pH. This phenomenon was more pronounced for the CBSH- strain. We explain some of these results using an hypothesis based on the consequence of dissociation of conjugated and deconjugated bile salts, and the value of their pKa.

Amidohydrolases↗
PubMed2000

Involvement of protein kinase C, tyrosine kinases, and Rho kinase in Ca(2+) handling of human small arteries.

The mechanisms of Ca(2+) handling and sensitization were investigated in human small omental arteries exposed to norepinephrine (NE) and to the thromboxane A(2) analog U-46619. Contractions elicited by NE and U-46619 were associated with an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), an increase in Ca(2+)-independent signaling pathways, or an enhancement of the sensitivity of the myofilaments to Ca(2+). The two latter pathways were abolished by protein kinase C (PKC), tyrosine kinase (TK), and Rho-associated protein kinase (ROK) inhibitors. In Ca(2+)-free medium, both NE and U-46619 elicited an increase in tension that was greatly reduced by PKC inhibitors and abolished by caffeine or ryanodine. After depletion of Ca(2+) stores with NE and U-46619 in Ca(2+)-free medium, addition of CaCl(2) in the continuous presence of the agonists produced increases in [Ca(2+)](i) and contractions that were inhibited by nitrendipine and TK inhibitors but not affected by PKC inhibitors. NE and U-46619 induced tyrosine phosphorylation of a 42- or a 58-kDa protein, respectively. These results indicate that the mechanisms leading to contraction elicited by NE and U-46619 in human small omental arteries are composed of Ca(2+) release from ryanodine-sensitive stores, Ca(2+) influx through nitrendipine-sensitive channels, and Ca(2+) sensitization and/or Ca(2+)-independent pathways. They also show that the TK pathway is involved in the tonic contraction associated with Ca(2+) entry, whereas TK, PKC, and ROK mechanisms regulate Ca(2+)-independent signaling pathways or Ca(2+) sensitization.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2000

Functional imaging of conditioned aversive emotional responses in antisocial personality disorder.

Individuals with antisocial personality disorder (n = 12) and healthy controls (n = 12) were examined for cerebral regional activation involved in the processing of negative affect. A differential aversive classical conditioning paradigm was applied with odors as unconditioned stimuli and faces as conditioned stimuli. Functional magnetic resonance imaging (fMRI) based on echo-planar imaging was used while cerebral activity was studied during habituation, acquisition, and extinction. Individually defined cerebral regions were analyzed. Both groups indicated behavioral conditioning following subjective ratings of emotional valence to conditioned stimuli. Differential effects were found during acquisition in the amygdala and dorsolateral prefrontal cortex. Controls showed signal decreases, patients signal increases. These preliminary results revealed unexpected signal increases in cortical/subcortical areas of patients. The increases may result from an additional effort put in by these individuals to form negative emotional associations, a pattern of processing that may correspond to their characteristic deviant emotional behavior.

Adolescent↗
PubMed2000

[Psychiatric problems after implantation of a cardioverter/defibrillator (ICD)].

The growing number of ICD patients diagnosed with malignant arrhythmias are often exposed to severe psychosocial stressors. In a number of cases, these stressors could lead to anxiety and depression. Although emotional stressors may be a major contributing factor in malignant arrhythmia, it is unfortunate that these symptoms are largely ignored. Therefore, additional psychiatric and psychotherapeutic treatment services for the prevention of sudden cardiac death seem advisable in certain cases.

Aged↗
PubMed2000

[Cannabis and tobacco: cofactors favoring juvenile obliterative arteriopathy].

The causal effect of cannabis, associated or not with smoking, in juvenile thromboangiitis disorders such as Leo Buerger disease, has been suggested. We describe here a case of a 30-year-old woman who smoked cannabis and developed intermittent claudication of the lower limbs. Female sex and proximal localization of the lesions (external iliac artery) are not usually described in "cannabis arteritis". Cannabis would be involved not only in the pathogenesis of juvenile obstructive arteriopathy, but also in the development of atheromatous lesions in the young subject.

Adult↗
PubMed1999

Generality and specificity of emotion-recognition deficit in schizophrenic patients with positive and negative symptoms.

Schizophrenic patients with positive and negative symptoms, as well as non-patient control subjects, were asked to recognize emotional stimuli of happy, sad, and neutral facial expressions. Dependent measures were the percentage of correct responses, and the incorrect use of an emotion category owing to false recognition. Schizophrenic patients with negative symptoms exhibited a generalized emotion-recognition deficit, and their use of emotion categories during false recognition was random. Schizophrenic patients with positive symptoms showed a deficit in their recognition of 'sad' emotion and were 'positively biased' to the category 'happy' as reflected by its most frequent usage during false recognition.

Adult↗
PubMed1999

Induction of nitric oxide synthase and dual effects of nitric oxide and cyclooxygenase products in regulation of arterial contraction in human septic shock.

BACKGROUND: The role of endogenous nitric oxide (NO) and cyclooxygenase metabolites was investigated in contractile responses of small omental arteries from patients with hyperdynamic septic shock. METHODS AND RESULTS: Expression of inducible NO synthase (immunostaining) and a high but variable level of NO production (NO spin trapping) was detected in arteries from patients with septic shock. In these vessels, ex vivo contractile responses to the thromboxane A2 analogue U46619 and to low concentrations of norepinephrine (NE) (up to 10 micromol/L) were not significantly different from controls. However, higher concentrations of NE caused pronounced fading of contraction in septic but not in nonseptic arteries. Exposure to either the NO synthase inhibitor NG-nitro-L-arginine methyl ester or the cyclooxygenase inhibitor indomethacin had no effect in control vessels. However, both inhibitors increased the response to the contractile effects of the 2 agonists only in patients with septic shock. In contrast to NG-nitro-L-arginine methyl ester, which decreased the threshold concentration of the fading effect of NE, indomethacin abolished this effect in arteries from septic patients. CONCLUSIONS: These results provide direct evidence for the induction of NO synthase in small arteries from patients with septic shock. They suggest that in these arteries, increased production of NO, in conjunction with vasodilatory cyclooxygenase metabolites, contributes to counteract hyperreactivity to agonists and decreases the cyclooxygenase product-mediated pronounced fading of contraction caused by a high concentration of NE.

Adult↗
PubMed1999

Correspondence of emotional self-rating with facial expression.

Emotional processing abilities are difficult to measure psychometrically. Ultimately their quantification has to rely on 'subjective' judgment thereby leaving open the problem of response biases. Assessments of autonomic arousal similarly provide a mere unspecified measurement of a specific emotion. A standardized mood induction procedure capable of obtaining reliable happy and sad mood changes in healthy subjects was used to demonstrate the effectiveness of this procedure. We performed a two-part experiment using a rater-based analysis of facial expressions. This entailed analyzing the emotion portrayed in the faces. The faces of 24 healthy subjects were videotaped during the mood induction procedure of happiness and sadness, respectively. A group of 20 raters naive to the experimental task and conditions rated the facial expressions on six basic emotions. Results showed that ratings corresponded with the facial expressions, which were reflecting the mood of the task condition. Subjects' facial expressions together with self-ratings demonstrate the successful applicability of this standardized mood induction procedure for eliciting happy and sad mood.

Adult↗