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István Bitter

Publications and source records attributed to István Bitter.

15 recordsLinked to original sources
PubMed2006

Uncatalyzed reactions in the classical Belousov-Zhabotinsky system. 2. The malonic acid-bromate reaction in acidic media.

The title reaction was studied with various techniques in 1 M sulfuric acid, a usual medium for the oscillatory Belousov-Zhabotinsky (BZ) reaction. It was found to be a more complex process than the bromomalonic acid (BrMA)-BrO3- reaction studied previously in the first part of this work. Malonic acid (MA) can react with acidic bromate by two parallel mechanisms. The main aim of the present research was to determine the mechanisms, the rate laws, and the rate constants for these parallel channels. In one reaction channel the first molecular products are glyoxalic acid (GOA) and CO2 while in the other channel mesoxalic acid (MOA) is the first molecular intermediate, that is, no CO2 is formed in this step. To prove these two independent routes specific colorimetric techniques were developed to determine GOA and MOA selectively. The rate of the GOA channel was determined by following the rate of the carbon dioxide evolution characteristic for this reaction route. In this step, regarding it as an overall process, one MA is oxidized to GOA and CO2 and one BrO3- is reduced to HOBr, which forms BrMA with another MA. The initial rate of the GOA channel is a bilinear function of the initial MA and BrO3- concentrations with a second-order rate constant k(GOA)= 2.4 x 10(-7) M(-1) s(-1). The rate of the other channel was calculated from the rate of the BrO3- consumption measured in separate experiments, assuming that the measured depletion is a sum of two separate terms reflecting the consumptions due to the two independent channels. In the MOA channel one MA is oxidized to MOA and one BrO3- is consumed while another MA is brominated as in the GOA channel. It was found that the initial rate of the MOA channel is also a bilinear function of the MA and BrO3- concentrations with a second-order rate constant k(MOA)= 2.46 x 10(-6) M(-1) s(-1). Separate chemical mechanisms are suggested for both channels. In all of the various bromate-substrate reactions of these mechanisms oxygen atom transfer from the bromate to the substrate occurs generating bromous acid intermediate. This can be of high importance in BZ systems as bromous acid is the autocatalytic intermediate there. GOA and MOA also can be oxidized by acidic bromate but a study of these reactions will be published later.

Journal Article↗
PubMed2006

[The beginnings of modern biological psychiatry in Hungary: the atropine coma. A historical overview].

In the authors' opinion modern biological psychiatry in Hungary started with the investigations into the biological mechanism of atropine coma therapy. Atropine coma was used in the period between 1950 and 1975 mainly in the treatment of various psychoses and obsessive compulsive disorder. In a previous communication the method, indications and adverse effects of atropine coma were outlined and the professional and broader social reasons for its eventual disappearance were discussed. In this paper the therapeutic effectiveness and research into the biological mode of action of atropine coma are summarized. Although thousands of patients received atropine coma therapy in the United States and in several Central-Eastern European countries including Hungary, this therapeutic modality is hardly ever features even in papers on the history of psychiatry. This is all the more surprising because initial therapeutic results with atropine coma were favourable and it seemed to be a more safe and efficient treatment than the more widely used insulin coma.

Atropine↗
PubMed2006

[Switching patients with schizophrenia to ziprasidone from conventional or other atypical antipsychotics].

OBJECTIVES: The aim of the study was to assess the efficacy, tolerability and safety of ziprasidone in patients with schizophrenia who were already treated with conventional or other atypical antipsychotics that had to be switched due the lack of efficacy or bad tolerance. METHODS: The study was a 12-week, open label, multicenter, non comparative trial on oral ziprasidone. 106 patients with DSM-IV schizophrenia were switched to ziprasidone from their previous antipsychotic without a washout phase. The study required fixed dosing with ziprasidone. For the first week the patient received 80 mg of study drug daily, followed for 3 weeks 120 mg/day. Subsequently for 8 weeks either 80 mg, or 120 mg, or 160 mg total daily dose could be given at the discretion of the investigator. Baseline and outcome assessment included Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Severity of Illness Subscale (CGI-S) and Global Improvement Subscale (CGI-I), Calgary Depression Scale (CAD), Hamilton Depression Scale (HAMD), Drug Attitude Inventory (DAI), Simpson Angus Extrapyramidal Symptoms Rating Scale (SAS) and Barnes Akathisia Rating Scale (BARS). Changes in overall body weight were also evaluated. RESULTS: After 12 weeks on ziprasidone therapy, significant improvements were observed on all major symptoms measures and subscales. 34 (51,5%) patients (ITT) were rated much or very much improved on CGI-I at week 12. The mean SAS score significantly reduced during the ziprasidone treatment period (p<0.001). In the DAI ziprasidone treatment was also favorable rated. During treatment with ziprasidone for 12 weeks the body weight of the patients was significantly reduced (mean: 1,2 kg, SD=3,79, p=0.002). 58 adverse events occurred in 41 subjects (38.7%), of whom 7 patients (6.6%) encountered 9 severe adverse events. The adverse events were mainly mild and moderate. 15 patients (14.2%) were discontinued from the study due to adverse events. The reason for discontinuation in 4 cases was mainly insufficient clinical response. CONCLUSION: Switching patients from their previous antipsychotic to ziprasidone without a washout phase was generally well tolerated and was associated with symptoms improvements 12 weeks later. At least 50% of patients who needed to be switched because of unsatisfactory efficacy or poor tolerance were significantly improved on ziprasidone therapy. The favorable safety profile of ziprasidone treatment was consistent with that seen in other clinical trials. KEYWORDS: switching, ziprasidone, schizophrenia.

Adult↗
PubMed2005

Unexpected effect of charge density of the aromatic guests on the stability of calix[6]arene-phenol host-guest complexes.

The pi-pi interaction-based inclusion complexation of calix[6]arene hexasulfonate as host with neutral aromatic guest molecules was studied in aqueous media. To vary the electron density on the guest's aromatic rings, the phenol parent compound was functionalized in the para-position with different electron-withdrawing groups, such as NO2 and Cl, as well as H and CH3 groups. To study the interaction between calixarene and the guests, PL, DSC, and quantum-chemical methods were used. The results indicate 1:1 stoichiometry for all examined host-guest complexes. Although the enthalpy change predicts strong interaction between the host and the guest, the Gibbs free energy change of the complex formation is small, resulting in a relatively low complex stability. This property is due to the high and negative entropy change during the complex formation. Comparing the thermodynamic parameters observed on the series of the guests, we observed a decrease of the enthalpy change when the electron density on the guest's aromatic ring increased. However, the Gibbs free energy and therefore, the stability of the complexes increased when the enthalpy change lowered. These unexpected results are based on the enthalpy-entropy compensation effect and probably due to the quite different entropy change related to the high and low electron density on the aromatic rings of different guest molecules. Using molecular dynamic calculations, a redistribution of the electron density of calixarene rings, followed by the reordering of the solvent molecules, was identified as a background of this unexpected entropy change at molecular level.

Journal Article↗
PubMed2005

Antipsychotic treatment and sexual functioning in first-time neuroleptic-treated schizophrenic patients.

The present study examined sexual functioning among first-time treated schizophrenia patients at the time that they initiated antipsychotic treatment, and again 3 and 6 months later. These first-time treated patients comprise a subgroup of 570 schizophrenia patients who were part of a cohort of 7,655 patients enrolled in the Intercontinental Schizophrenia Outpatient-Health Outcomes observational study (IC-SOHO). As part of a brief clinical assessment conducted at entry to the study, and after 3 and 6 months of antipsychotic medication, patients were asked to rate their sexual functioning, and the investigator was asked to rate the extent to which the patient had neuroleptic-related loss of libido and sexual dysfunction. After being treated, patients treated with olanzapine showed the lowest prevalence of neuroleptic-induced sexual difficulties. At 3 months, there were significant differences between the treatment groups on neuroleptic-related loss of libido, neuroleptic-related sexual dysfunction and change in patient-rated sexual dysfunction. At 6 months, the difference between the groups on neuroleptic-related loss of libido was statistically significant. There were no significant differences between males and females. Many recent onset patients appear to suffer from problems of sexual functioning. Olanzapine may offer an advantage in this area.

Adult↗
PubMed2005

Atropine coma: a historical note.

Insulin coma and various types of convulsive therapies were the major biologic treatment modalities in psychiatry before the psychopharmacological era. Except for electroconvulsive therapy (ECT), these methods disappeared from the psychiatric armamentarium after the introduction of psychotropic drugs. Atropine coma therapy (ACT) was one variety of nonconvulsive coma therapy used from the 1950s in a few state mental hospitals in the United States and in several Middle- and Eastern European countries until the late 1970s. In ACT, a coma of 6-10 hours' duration was induced with doses of parenteral atropine sulfate that were hundreds of times greater than the therapeutic dose administered in internal medicine. Although ACT was given to thousands of patients with a variety of diagnoses for nearly 3 decades, it is rarely mentioned, even in papers on the history of psychiatry. The method, indications, contraindications and adverse effects of ACT are summarized together with patients' personal accounts. Hypotheses concerning its mode of action are briefly mentioned. The reasons why ACT never gained wider acceptance are explored in the context of both contemporary psychiatric practice and the broader sociocultural climate of the era.

Atropine↗
PubMed2005

Absorption and fluorescence spectroscopic study on complexation of Oxazine 1 Dye by calix[8]arenesulfonate.

It has been established by combined absorption and fluorescence measurements that the cationic dye Oxazine 1 (OX) and the polyvalent anionic host calix[8]arenesulfonate (SCA8) form two complexes in simultaneous reactions: OX + SCA8 <--> OX.SCA8 (1), and OX.SCA8 + OX <--> OX(2).SCA8 (2). The equilibrium constants for the two reactions, as functions of the ionic strength (I), and the absorption and fluorescence spectra of the two complex species have been determined by a least-squares fitting method from the experimental data. The variations of the binding constants with the ionic strength could be described on the basis of Debye-Huckel theory. The equilibrium constants are large; their values extrapolated to I = 0 are K(1) = 5.5 x 10(6) M(-1) and K(2) = 4.4 x 10(5) M(-1). The fluorescence of OX undergoes a strong static quenching upon complexation. These results indicate that the complexes are held together by strong electrostatic forces. The addition of non-fluorescent tetramethylammonium chloride to OX-SCA8 mixtures results in a dramatic fluorescent enhancement, which demonstrates the potential applicability of this supramolecular system in fluorescence assays.

Calixarenes↗
PubMed2004

Unprecedented cyclizations of calix[4]arenes with glycols under the Mitsunobu protocol, part 2.(1) O,O-and O,S-bridged calixarenes.

[reaction: see text] Cycloalkylations of p-tert-butylcalix[4]arene (CA) and p-tert-butylthiacalix[4]arene (TCA) with various aliphatic glycols were performed under the Mitsunobu protocol using the DEAD/TPP system. CA gave 1,3-dialkylated diols, while C(2)-C(10) glycols gave 1,2- and 1,3-bridged calixarenes. The reaction of TCA with C(2) diols afforded sulfonium phenoxide betaines via O,S-cyclization, which is the first example for the alkylation of the sulfide bridge.

Journal Article↗
PubMed2004

[Current pharmacotherapy of schizophrenia].

Second generation antipsychotics have become the standard of modern pharmacotherapy of schizophrenia. Amisulprid, clozapine, olanzapine, quetiapine, risperidone, sertindol, ziprasidone are the second generation antipsychotics registered in Hungary. They are more efficacious and their side effects are less stigmatizing than those of the first generation of antipsychotic drugs. Their use is limited by the availability of different formulations, by the lack of experience of some physicians, however the main limitation is the economic barrier.

Amisulpride↗
PubMed2004

Absorption, fluorescence, and cd spectroscopic study of chiral recognition by a binaphthyl-derived chromogenic calixcrown host.

The (R)- and (S)-enantiomers of a binaphthyl-appended calix[4]crown-6 ether with two 2,4-dinitrophenylazo chromophore units ((R)-1 and (S)-1) as chiral hosts were tested in their reactions with the enantiomers of alpha-methylbenzylamine ((R)-MBA, (S)-MBA)) and phenylglycinol ((R)-PGL, (S)-PGL) as chiral guests. The visible absorption spectra indicate a two-step process: the first is a nonenantioselective proton transfer from the host to the guest, which is followed by the enantioselective real complexation. In the visible range of the CD spectra a positive/negative band belongs to the absorption of pure (R)-1/(S)-1, and a negative/positive exciton couplet to the absorption of (R)-1-(S)-MBA/(S)-1-(R)-MBA complexes. The latter phenomenon suggests that the complexation of amines is accompanied by a chiral arrangement of the two chromophore units in the hosts. The UV fluorescence of (R)-1/(S)-1 arising from the binaphthyl moiety is quenched by K+ ions, but not by the amine guests, showing that the interaction between the binaphthyl group and the complexed amines is weak.

Journal Article↗
PubMed2003

Prevalence and comorbidity of affective disorders in persons making suicide attempts in Hungary: importance of the first depressive episodes and of bipolar II diagnoses.

BACKGROUND: The purpose of this study was to investigate the prevalence and comorbidity of affective disorders, especially current major depressive episode and bipolar disorder among suicide attempters in Hungary. METHODS: Using a structured interview (Mini International Neuropsychiatric Interview) determining 16 Axis I psychiatric diagnoses defined by the DSM-IV and a semistructured interview collecting background information, the authors examined 100 consecutive suicide attempters, aged 18-65. RESULTS: Eighty-eight percent of the attempters had one or more current diagnoses on Axis I. In 69% it was major depressive episode and 60% of them were suffering their first episode. Thirty-five percent of the patients with current major depressive episode had had hypomanic (n=19) or manic (n=5) episodes in the past. Seventy percent of the individuals received two or more current diagnoses on Axis I. Eighty-six percent of all current Axis I disorders (except major depressive episode) were diagnosed together with a current major depressive episode. The diagnosis of current major depressive episode and the number of current psychiatric disorders was significantly and positively related to the number of suicide attempts, but the diagnosis of past major depressive episode was not. LIMITATIONS: This study included suicide attempters who had presented selfpoisoning, but not individuals with very high risk of fatality. CONCLUSIONS: In suicide attempters there is a very high prevalence of affective disorders, especially major depression, first episode of major depression and bipolar II disorder. This study underlines the importance of early detection and treatment of psychiatric disorders for the prevention of suicidal behavior.

Adolescent↗
PubMed2003

Intramuscular olanzapine and intramuscular haloperidol in acute schizophrenia: antipsychotic efficacy and extrapyramidal safety during the first 24 hours of treatment.

OBJECTIVE: To determine the antipsychotic efficacy and extrapyramidal safety of intramuscular (i.m.) olanzapine and i.m. haloperidol during the first 24 hours of treatment of acute schizophrenia. METHOD: Patients (n = 311) with acute schizophrenia were randomly allocated (2:2:1) to receive i.m. olanzapine (10.0 mg, n = 131), i.m. haloperidol (7.5 mg, n = 126), or i.m. placebo (n = 54). RESULTS: After the first injection, i.m. olanzapine was comparable to i.m. haloperidol and superior to i.m. placebo for reducing mean change scores from baseline on the Brief Psychiatric Rating Scale (BRPS) Positive at 2 hours (-2.9 olanzapine, -2.7 haloperidol, and -1.5 placebo) and 24 hours (-2.8 olanzapine, -3.2 haloperidol, and -1.3 placebo); the BPRS Total at 2 hours (-14.2 olanzapine,-13.1 haloperidol, and -7.1 placebo) and 24 hours (-12.8 olanzapine, -12.9 haloperidol, and -6.2 placebo); and the Clinical Global Impressions (CGI) scale at 24 hours (-0.5 olanzapine, -0.5 haloperidol, and -0.1 placebo). Patients treated with i.m. olanzapine had significantly fewer incidences of treatment-emergent parkinsonism (4.3% olanzapine vs 13.3% haloperidol, P = 0.036), but not akathisia (1.1% olanzapine vs 6.5% haloperidol, P = 0.065), than did patients treated with i.m. haloperidol; they also required significantly less anticholinergic treatment (4.6% olanzapine vs 20.6% haloperidol, P < 0.001). Mean extrapyramidal symptoms (EPS) safety scores improved significantly from baseline during i.m. olanzapine treatment, compared with a general worsening during i.m. haloperidol treatment (Simpson-Angus Scale total score mean change: -0.61 olanzapine vs 0.70 haloperidol; P < 0.001; Barnes Akathisia Scale global score mean change: -0.27 olanzapine vs 0.01 haloperidol; P < 0.05). CONCLUSION: I.m. olanzapine was comparable to i.m. haloperidol for reducing the symptoms of acute schizophrenia during the first 24 hours of treatment, the efficacy of both being evident within 2 hours after the first injection. In general, more EPS were observed during treatment with i.m. haloperidol than with i.m. olanzapine.

Acute Disease↗
PubMedDate not supplied

Anisotropy decay study on the host-guest interaction of distally dialkylated calix[4]arenes with 1-chloro-4-(trifluoromethyl)benzene.

The 'host' properties of distally dialkylated calix[4]arenes and 4-tert-butylcalix[4]arenes in the presence of 1-chloro-4-(trifluoromethyl)benzene (BFT) were studied in chloroform solvent by intensity-independent spectrofluorometric method. The anisotropy decay experiments were found as suitable method to indicate the host-guest complex formation but it is unable to determine the strength of supramolecular interaction.

Benzene↗