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Biomedical subjects

F Schneider

Publications and source records attributed to F Schneider.

At least 181 records · Page 10Linked to original sources
PubMed1996

Protection against measles virus encephalitis by monoclonal antibodies binding to a cystine loop domain of the H protein mimicked by peptides which are not recognized by maternal antibodies.

After immunization with measles virus (MV) several monoclonal antibodies (MAbs) were obtained, which reacted with peptides corresponding to the amino acids 361-410 of the haemagglutinin protein (MV-H). Three of these MAbs (BH6, BH21 and BH216) inhibited haemagglutination, neutralized MV in vitro and protected animals from a lethal challenge of rodent-adapted neurotropic MV. These MAbs reacted with the 15-mer peptides H381 and H386 defining their overlapping region 386-395 as a sequential neutralizing and protective epitope, which can be imitated by a short peptide. H381 and H386 share two Cys residues (C(386)KGKIQALC(394)ENPEWA) and for optimal MAb binding of peptide (or MV) disulphide bonds were required in addition to a linear C-terminal extension. Other MAbs bound to peptides C- (BH147, BH195) and N-terminally (BH 168, BH 171) adjacent to the loop but did not neutralize or protect. When sera from measles patients or from women of child-bearing age were tested with the peptides corresponding to this haemagglutinating and neutralizing epitope (HNE), none of the sera recognized the 15-mer peptides of this region, while some reactivity was found to 30-mers homologous to different wild-type mutants. Its lack of recognition by maternal antibodies and its high degree of conservation would make the HNE loop an attractive candidate to include into a subunit vaccine, which could be administered during early childhood, independent of immune status.

Amino Acid Sequence↗
PubMed1996

Effects of ergotamine and dihydroergotamine on 5-hydroxytryptamine-2A receptors in the isolated rat aorta.

Ergotamine contracted isolated rat aorta rings with an intrinsic activity of 50% of that of 5-hydroxytryptamine. (5-HT, 0.1 mmol/l). Dihydroergotamine did not contract the tissue, but insurmountably blocked contraction in response to ergotamine and 5-HT. The 5-HT2A receptor antagonist, ketanserin (0.1 mumol/l), inhibited ergotamine (pKB 8.0) and 5-HT (pKB 8.1) induced contractions. These results indicate that in the rat aorta ergotamine is a partial 5-HT2A receptor agonist, whilst dihydroergotamine is an insurmountable 5-HT2A receptor antagonist. The present data could explain why ergotamine displays more cardiovascular and uterotonic side effects than dihydroergotamine.

Animals↗
PubMed1996

Cerebral blood flow changes in limbic regions induced by unsolvable anagram tasks.

OBJECTIVE: The study addressed the question of whether unsolvable as opposed to solvable cognitive problems activate discrete neuronal systems in the human brain. METHOD: Twelve healthy humans tried to solve unsolvable anagrams. Solvable anagrams and a resting baseline after each anagram task served as control conditions in a within-subject design. Activation was measured with the equilibrium infusion method by using 15O-labeled water and positron emission tomography, with absolute quantitation of anatomically defined regional cerebral blood flow (CBF). RESULTS: Compared to rest, both anagram tasks increased activity in frontal and temporal regions. The soluble task condition increased hippocampal activation and decreased mammillary bodies activity, while unsolvable anagrams were associated with increased CBF to the mamillary bodies and amygdala and decreased hippocampal activity. CONCLUSIONS: A limbic network integrating negative emotion and cognition seems reflected in reciprocal diencephalic and limbic activation with solvable and unsolvable anagrams. Since unsolvable anagrams have been used to induce learned helplessness in humans, this finding may provide an initial step toward clarifying its neural substrate.

Adult↗
PubMed1996

Plasma cyclic GMP concentrations and their relationship with changes of blood pressure levels in pre-eclampsia.

BACKGROUND: One of the possible mechanisms responsible for pre-eclampsia is a loss of efficiency of the L-arginine-nitric oxide pathway with subsequent inactivation of the guanylyl cyclases of the vascular smooth muscle cells. As a result there should be a decrease in plasma cyclic 3'-5' guanosine monophosphate (cGMP) concentrations in pre-eclampsia. We assessed the behavior of this nucleotid in the plasma of pre-eclamptic women. SUBJECTS AND METHODS: Sixteen pre-eclamptic women, 16 normotensive pregnant women matched for gestational age and six nonpregnant controls were investigated. Arterial blood pressure was recorded at inclusion time and then once-a-day until the fourth day after delivery concomitantly with the collection of blood samples for determining plasma cGMP, atrial natriuretic peptides (ANP), creatinine, uric acid and platelet counts. Also 24 h urines were simultaneously collected to calculate renal clearance of cGMP. RESULTS: Before the initiation of antihypertensive treatment, plasma cGMP levels were significantly higher (p < 0.01) in pre-eclampsia women as compared both to pregnant normotensive controls and nonpregnant women (7.02 +/- 0.9 versus 4.8 +/- 0.76 versus 1.93 +/- 0.15 pmol.ml-1, p < 0.01). Under antihypertensive treatment, cGMP levels decreased significantly (p < 0.05) to 5.48 +/- 0.9 pmol.ml-1. The increase of plasma cGMP was associated with high ANP levels; the likelihood that a renal impairment could account for an increase in plasma cGMP was ruled out because the clearance of creatinine was not impaired. Similarly the possibility of a significant linear correlation between cGMP levels and blood pressure values or biological data was excluded in these women. CONCLUSION: Plasma cGMP concentrations are increased in pre-eclampsia. They decrease to control values when blood pressure returns to normal values; they indicate enhanced guanylyl cyclase activation by ANP and additional factors, but cannot be considered as a direct index of the severity of pre-eclampsia.

Adult↗
PubMed1996

Plasma and urine concentrations of atropine after the ingestion of cooked deadly nightshade berries.

BACKGROUND: Adult intoxications due to ingestion of deadly nightshade berries is uncommon. CASE REPORTS: Collective intoxication of eight persons occurred after accidental ingestion of ripened Atropa belladonna berries. Three of the four adults displayed delirious states with visual hallucinations; one patient fell into a coma and required mechanical ventilation. Four children and one adult exhibited mild peripheral anticholinergic symptoms. Kinetic data were obtained on the three hospitalized adults. DISCUSSION: The optimal intensive care for such patients is discussed.

Adult↗
PubMed1996

[Application of GnRH-agonists in young sows affects cyclic gonadotropin release].

Gonadotropin-releasing hormone (GnRH) controls by pulsatile secretion the synthesis and release of LH and FSH. In contrast to the endogenous peptide a long-term treatment of GnRH agonists (GnRH-A) initiates a continuous stimulation. The aim of the present study was to determine the influence of a GnRH-A on peripheral LH, FSH and steroid concentrations, measured by specific RIA methods, in cyclic gilts. Therefore blood samples were drawn via i.v. catheters once daily (8 h) and frequently every second day for six hours (8-14 h) in 20 min intervals. The experiment was started on day 10 of the oestrus cycle. Four gilts were injected with 7.5 mg triptorelin (D-Trp6-LHRH, Decapeptyl) and three gilts injected with vehicle served as control. The administration of GnRH-A induced a release of FSH and LH within the first one or two hours lasting 2-6 h. After this initial peak gonadotropin levels remained in a low range. In control gilts LH and FSH remained at basal level and increased between day 20-21. There was only a small number of LH pulses (n = 5) or no FSH pulses after GnRH-A during the intensive sampling periods. In untreated gilts the mean LH pulse frequency increased from 0.67 +/- 0.47 on day 12 to 2.0 +/- 1.63 to 1.5 +/- 0.5 on day 16-20. Differences in pulse amplitudes were observed during the oestrus cycle. Defined FSH pulses were not detected. The basal LH and FSH levels were not affected by GnRH-A treatment. Follicular development and ovulation were down-regulated following GnRH-A. The results indicate that GnRH agonists in a longtime active depot formulation induce their suppressive effects on ovarian function in gilts by marked decrease of pulsatile gonadotropin release.

Animals↗
PubMed1996

[Analysis of regional differences in hospitalization rate and length of stay costs].

PROBLEM: Performance of an analysis of hospitalised cases based on processed statutory health insurance data on inpatient treatments. Object of the examination were regional differences in the frequency of hospitalisation and in the volume of payable (invoised) days and the relevant determining parameters. MATERIAL AND METHODS: The analysis is based on a total of 152,854 cases of hospitalisation recorded in 1994 by the Magdeburg Statutory Health Insurance Body. These include data (rendered anonymous) on each insured person and on the specialist branch of the referring physician, case characteristics as well as characterising features of the hospital. Additionally, 249,471 diagnosis recordings are available from the total of the recorded cases. RESULTS: There is considerable regional variation in the number of hospital care days within the area of the Magdeburg Statutory Health Insurance Body. These regional differences are noticeable both in the frequency of referrals (broken down according to the regional statutory health insurance offices) and in the average duration of stay (in the hospitals of the region). Reasons for this heterogeneity are evident from the structural conditions of medical care by the physicians under contact with the statutory health insurance body (greater frequency of referral to hospital in areas where there are fewer doctors per 10.000 inhabitants and with less voluminous practices) and from different management strategies of hospitals even if medical care services are well standardised. DISCUSSION: The results prompt more detailed analyses of inpatient care activities including structural parameters of the outpatient sector. Actually we can recognise certain limitations preventing a uniform patient care by statutory health insurance physicians and uniform inpatient care, in the sense imposed by the official policy to ensure such uniformity.

Costs and Cost Analysis↗
PubMed1995

Mood effects on limbic blood flow correlate with emotional self-rating: a PET study with oxygen-15 labeled water.

Positron emission tomography was used to study the effects of experimentally controlled mood states on cerebral blood flow (CBF), measured with the quantitative equilibrium infusion method and 15O-labeled water. Twenty-seven brain regions in each hemisphere were assessed in 16 normal subjects. CBF and heart rate were measured during happy and sad mood induction, and during two nonemotional control conditions: sex differentiation and resting baseline. Valence-specific effects of mood on CBF were obtained for subcortical, but not for frontal-temporal or control regions. CBF increased in left amygdala and decreased in right amygdala during sad mood relative to the averaged control conditions. These changes correlated with shifts toward negative affect. Correlations were opposite for subcortical (negative affect associated with lower left hemispheric CBF) compared with frontal-temporal cortical regions. Results support limbic involvement in regulating emotional states and suggest some reciprocity between subcortical and frontal-temporal regulation of emotional experience.

Adolescent↗
PubMed1995

[Vertical transmission causing hepatitis C in a newborn infant].

There is a case report of an intrauterine growth retarded infant who was suffering of sepsis caused by Klebsiella pneumoniae. An exchange transfusion was carried out because of hyperbilirubinaemia on the 5th day of life. 10 days later high bilirubin concentration was observed again parallel to the liver enzyme abnormalities. HCV-related antibodies were detectable in the sera of the newborn and his mother as well. The results of analysis of HCV RNA with the polymerase chain reaction in the infant and his mother suggest vertical transmission of HCV infection. This is the first case of HCV infection in the newborn caused by vertical transmission in Hungary.

Bilirubin↗
PubMed1995

Specific inhibition of plant fatty acid elongation by a long-chain cerulenin analogue.

Cerulenin analogues with 16 or 18 carbon atoms inhibit both ATP-dependent and acyl-CoA-dependent fatty acid elongations. Prior incubation of microsomes with inhibitors is necessary to obtain maximal inhibition. The analogues act on the first reaction of the elongation process catalysed by the 3-ketoacyl-CoA synthase. The 18-carbon analogue has no, or little, effect on the fatty acid synthesis, while cerulenin and its 16-carbon analogue totally inhibit this synthesis. The 18-carbon analogue appears to be a specific inhibitor of the synthesis of very long-chain fatty acids, with no effect on de novo fatty acid synthesis.

Cerulenin↗
PubMed1995

Bifidobacteria and probiotic effects: action of Bifidobacterium species on conjugated bile salts.

The effect of six different conjugated bile salts (two trihydroxyconjugated bile salts: tauro and glycocholic acids; and four dihydroxyconjugated bile salts: tauro- and glycochenodeoxycholic, tauro- and glycodeoxycholic acids) on eight bifidobacteria strains were studied. A strong growth-inhibitory effect was observed (80% at 0.95 mM) for each bile salt and strain. This phenomenon was explained by the production of deconjugated bile salt during bifidobacteria growth. The deconjugation phenomenon was concurrent with biomass production, and deconjugated bile salts were the sole compound produced during bifidobacteria biotransformation. In resting cell experiments, differences appeared between the strains and the kind of bile salts, particularly concerning taurocholic acid. The Bifidobacterium longum strains were the most efficient among the bacteria tested.

Bifidobacterium↗
PubMed1995

Intramolecular immunodominance and intermolecular selection of H2d-restricted peptides define the same immunodominant region of the measles virus fusion protein.

The generation of a sustained antibody response requires the participation of MHC class II-restricted T helper cells. We have identified class II-restricted sequences by immunizing BALB/c (H-2d) mice with 108 overlapping synthetic pentadecapeptides covering the whole sequence of the measles virus fusion protein (MV-F). Several strong T cell epitopes were found including a major cluster of H-2d-restricted peptides between amino acids 256 and 305. Some of these peptides including peptide F(421-435) and F(256-270) induced MV-specific T lymphocytes in vivo while other H2d-restricted MV-F sequences did not. Immunization with mixtures of selected peptides indicated a hierarchy among H2d-restricted sequences due to competition between peptides. The dominant peptide F(421-435) impaired the response to other T cell epitopes including F(256-270). The response to F(91-105) was obliterated by F(421-435) and F(256-270) but not by peptides devoid of a T cell epitope. When BALB/c mice were immunized with the MV, the immunodominant sequence F(421-445) was identified which included the synthetic peptide F(421-435). Our data suggest that competition during processing and/or presentation between H2d-restricted peptides defines the immunodominant sequence of the viral protein. Even though only a single immunodominant region was defined after immunization with the MV, peptides from other regions were able to induce MV-specific T cell responses. This finding is of interest for the design of subunit vaccines in general and for studying MV-specific T helper cells in an animal model in particular.

Amino Acid Sequence↗
PubMed1995

Reduced emotional response of schizophrenic patients in remission during social interaction.

Inappropriate emotional response during social interaction is a prominent feature of schizophrenia during the acute stage of illness. This study evaluates the course of reduced facial activity in schizophrenic patients in remission and compares it with healthy controls. The experimental conditions included watching two films, one inducing happy and the other sad emotional states. Each is followed by an interview eliciting happy and sad feelings. The facial actions were recorded (1) by a computer-based analysis of recordings of the skin movement and (2) by electromyography of the corrugator and zygomaticus muscles. Twenty schizophrenic patients in remission and 20 normal controls participated in the study. In contrast to previously studied acute patients, there was no overall reduction of facial expression in the upper face of schizophrenic patients in remission. Patients showed fewer movements (automatic analysis) of the lower face during the happy interview and more movements during the sad interview compared with controls. Furthermore, schizophrenic patients showed reduced zygomaticus activity (EMG) during both the happy film and the interview, suggesting a reduced ability of schizophrenic patients to express happy facial expressions, such as smiling, in the lower face. This may indicate a reduced variability in emotional response in schizophrenia.

Adult↗
PubMed1995

Emotional processing in schizophrenia: neurobehavioral probes in relation to psychopathology.

The application of neurobehavioral methods in functional neuroimaging can provide useful information on the neurobiology of schizophrenia. This process can be enhanced by using a standard set of procedures to construct 'neurobehavioral probes' which are suitable for functional imaging and provide reliable measures discriminating patients from healthy controls. While such probes are available for cognitive tasks, none has been applied to study emotional processing in schizophrenia. We examined emotional discrimination and experience probes and correlated performance with cognitive and clinical measures. Emotion discrimination tasks and mood induction procedures with happy, sad, and neutral facial expressions were administered to 40 patients with schizophrenia. Neuropsychological testing assessed intellectual, attention, abstraction-flexibility, memory, language, spatial, and sensory-motor functions. Emotional performance was compared to a group of 40 normal subjects. Performance for face discrimination was impaired in patients. There was specific impairment in discrimination of happy expressions. Mood induction was effective in both groups, but diminished in patients, especially for happiness. Poorer performance in emotion discrimination correlated with severity of negative symptoms and bizarre behavior. Hallucinations were associated with more pronounced mood induction effects. Emotion discrimination was also correlated with abstraction, memory, language and spatial tasks, while mood induction effects showed no such associations. Thus, the impairment in discriminating and experiencing valence-specific emotions in schizophrenia relates to symptomatology and neuropsychological functioning. The results encourage the use of the emotion discrimination task and the mood induction procedure as neurobehavioral probes in physiologic neuroimaging studies for investigating the neural substrates of emotion.

Adult↗
PubMed1995

Cholera toxin B stimulates systemic neutralizing antibodies after intranasal co-immunization with measles virus.

An efficient mucosal vaccination has a number of obvious advantages over invasive routes of immunization. The immune response to measles virus (MV) was investigated after intranasal and intragastric co-immunization of mice with cholera toxin B (CTB) as an adjuvant. High titres of virus-specific IgG antibodies and a transient IgA response were detected in the sera after intranasal but not after intragastric immunization when CTB was used. In the presence of CTB, higher titres were reached with less antigen and fewer intranasal boosts. Neutralizing antibodies were found in all animals only after co-immunization with MV and CTB. In the nasal wash and the saliva, IgG and IgA titres were significant only in the MV plus CTB groups; IgG levels were comparable to those found after intraperitoneal (i.p.) immunization with complete Freund's adjuvant. Specific IgA was detected in the mucosal fluids only after intranasal immunization with MV plus CTB but not after i.p. or intragastric immunization. The antibody response consisted of 99% IgG1 after MV immunization. In the CTB groups 10% IgG2b and 1% IgG2a were detected in addition to the predominant IgG1 antibodies.

Adjuvants, Immunologic↗