Biomedical subjects

P Richter

Publications and source records attributed to P Richter.

At least 19 recordsLinked to original sources

PubMed1998

[Time perception and time estimation in depressive patients].

Subjective time-experience and objective time-estimation were examined in 20 endogenous, 20 neurotic depressives, and 15 healthy volunteers. Subjective experience of past and anticipated future time was more extended in both depressive groups than in healthy controls. Objective time estimation differed between depressives and controls concerning relatively long time spans whereas very short time spans were correctly estimated also by depressives. There were no significant differences between endogenous and neurotic depressives. The perception of extended time normalized during treatment. The depressives' time perception, differences correlated with the extent of depressive psychopathological symptoms and--to a lesser degree--with retardation. The findings support the hypotheses of anthropological phenomenology concerning disturbed time perception and estimation in depressives. Amelioration of experienced time-extension in intentionally structured time spans compared to empty time spans suggests psychotherapeutic consequences in the sense of Lewinsohn.

Adult↗

PubMed1998

[Dimensions of schizophrenia in the elderly. Correlations with cognitive and motor symptoms].

In most factor analytical studies of schizophrenic symptomatology a three-factor solution was found. The aim of this study was to investigate symptomatological dimensions in old age and to clarify whether the dimensions correlate differently with neuropsychological and motor parameters. A total of 131 DSM-III-R schizophrenics (mean age 68 years) were assessed using SANS, SAPS, a neuropsychological test battery and motor scales. A factor analysis yielded three dimensions (negative, disorganized, paranoid), two of which (negative, disorganized) showed different correlations with neuropsychological and motor phenomena. Thus, three symptomatological dimensions could also be demonstrated in a chronic, old-age schizophrenic sample. The pathophysiological significance of the different correlations with neuropsychological and motor parameters should be clarified in neuroimaging and neuropathological studies.

Aged↗

PubMed1998

Psychophysiological analysis of mental load during driving on rural roads--a quasi-experimental field study.

The objective of this study was the development and validation of an integrated measure-assessment approach (driving performance and psychophysiological indicators) for the assessment of driving demands of rural road segments as a starting point for design. With 31 student test drivers and a selection of six study roads, the reactivity of psychophysiological parameters was evaluated based on a general model of cognitive-energetic effort regulation according to Hockey (1993). The road curvature change rate was introduced as the independent variable, which served as a criterion of objective road difficulty. Based on a reliability analysis, the longitudinal and cross-sectional stability, especially for heart rate (HR) and blink rate (BR) measures, is sufficiently high. Both these psychophysiological variables and speed vary as a function of the curvature change rate of the rural road segments. The speed parameter differentiates very strongly the different curvature change rates. Among the psychophysiological indicators, changes in the blink rate almost exactly mirror the level of the curvature change rate owing to the fact that the BR decreases almost steadily with increasing curvature change rate. Cardiovascular parameters, such as heart rate (HR) and heart rate variability (HRV), and skin conductance response (SCR) also vary in relation to driving difficulty of road segments, but at levels of intermediate curvature other additional road characteristics may also influence these measures.

Adult↗

PubMed1998

Personality patterns and outcome in depressive and bipolar disorders.

Personality traits and disorders have a strong influence on the course and outcome of depressive and bipolar disorders. Studies of the influence of personality disorders (PD) and some PD clusters on outcome of mood disorders are controversial and suggest that more specific assessment of underlying traits or dimensions is needed. Utilizing the Munich Personality test (MP-T) scales of von Zerssen, this study tries to identify specific personality traits that may influence the outcome and clinical course of unipolar endogenous depression and bipolar disorder. Six unipolar depressives and 6 bipolar patients, according to DSM III-R and ICD 10 criteria, were assessed with the MP-T self- and family-reporting scales. Three years later, their outcome scores were correlated with the corresponding premorbid personality profile. Preliminary results show that introversion has a negative effect on outcome of unipolar melancholic depression, while extraversion, esoteric tendencies and rigidity have a positive influence. Neuroticism has a negative influence on outcome of bipolar disorder, but not on unipolar endogenous depression. Data from the literature suggest that neuroticism, hostility and social dysfunction seem to have a negative prognostic value only for nonendogenous depressives and bipolar disorder, thus supporting the notion that the diagnostic distinction between bipolar disorder, endogenous and nonendogenous depression is relevant to prognostic discussions. These observations help to understand the differences between depressive syndromes and their relationship to prognosis, but also to comprehend the role of personality in clinical and theoretical research of mood disorders.

Adult↗

PubMed1998

On the validity of the Beck Depression Inventory. A review.

The present review discusses validity aspects of the Beck Depression Inventory (BDI) on the basis of meta-analyses of studies on the psychometric properties. Shortcomings of the BDI are its high item difficulty, lack of representative norms, and thus doubtful objectivity of interpretation, controversial factorial validity, instability of scores over short time intervals (over the course of 1 day), and poor discriminant validity against anxiety. Advantages of the inventory are its high internal consistency, high content validity, validity in differentiating between depressed and nondepressed subjects, sensitivity to change, and international propagation. The present paper outlines agreements and contradictions between the various studies on the BDI and discusses the potential factors (composition of the subject sample, statistical procedures, point in time of measurement) accounting for the variance in their results. The Beck Depression Inventory (BDI) is world-wide among the most used self-rating scales for measuring depression. Since the test construction in 1961, the test has been employed in numerous (more than 2,000) empirical studies. The present review will only consider those investigations which are primarily concerned with the validity or the psychometric properties of the BDI. Since most studies are oriented along the criteria of the classical test theory, our review will discuss to what extent the BDI meets these criteria.

Depressive Disorder↗

PubMed1997

Kinetic and safety studies on intrathecally infused recombinant-methionyl human brain-derived neurotrophic factor in dogs.

To define the kinetics and safety of spinally infused recombinant-methionyl human brain-derived neurotrophic factor (r-metHuBDNF), beagle dogs were prepared with lumbar intrathecal catheters passed through the cisternal membrane to the L1-L4 lumbar level. For kinetic studies, r-metHuBDNF was delivered by bolus or infusion through one catheter and lumbar CSF was sampled periodically through a second. As a lumbar bolus, r-metHuBDNF displayed a biphasic clearance with t(1/2)a = 0.7 hr and t(1/2)b = 7. 9 hr. Lumbar to cisternal concentrations after bolus delivery were approximately 60:1. For safety studies, dogs received continuous intrathecal infusion (2.4 ml/day) for 28 days of saline (n = 6), r-metHuBDNF at 200 (n = 6), 800 (n = 6), or 2000 (n = 7) microg/day. Control dogs showed no changes. Intrathecally infused r-metHuBDNF produced a dose-dependent increase in muscle tone and decreased coordination. Low-dose r-metHuBDNF was associated with moderate increases in muscle tone after 22-28 days of infusion. No clinically important changes were noted in rectal temperature, arterial pressure, respiration and heart rate, body weight, food consumption, stool or urine output, or change in blood chemistries measured throughout the study. Cisternal CSF protein and glucose sampled at 28 days were not different between dose groups and all cultures were negative. Histopathological examination of the spinal cord typically revealed some degree of chronic inflammation around the catheter, including fibrotic adhesions and focal accumulations of lymphoid and plasma cells, but these effects were not dose dependent. In other dogs receiving r-metHuBDNF (2000 or 4000 microg/day), termination of infusion resulted in significant recovery.

Animals↗

PubMed1997

Identification of alkylpolyoxyethylene glycols in the residues after biodegradation of their mixtures by CGC and previous derivatization.

This study deals with the identification of individual n-alkylpolyoxyethylene glycols among the products of oxyethylenation of n-nonyl- and n-decylalcohol and with the identification of these compounds in the reaction mixture after their biodegradation. The individual glycols were identified by their retention indices for the column temperature programmed linearly, by the correlation of the retention indices with the number of oxyethylene groups in the molecule and by increments of retention indices for the incoming oxyethylene group or methylene group. The biodegradation process of oxyethylenation products of reaction of one mole of n-nonylalcohol and n-decylalcohol, respectively, with three moles of ethylene oxide was studied. n-Alkylpolyoxyethylene glycols in oxyethylenation products or their residues isolated from the aqueous solution after their biodegradation processes were derivatized into acetates, trifluoroacetates and trimethylsilyl derivatives before carrying out their identification and determination.

Acetates↗

PubMed1997

Personality differences between patients with major depression and bipolar disorder--the impact of minor symptoms on self-ratings of personality.

The study explores whether minor symptoms of patients in recovery from a mood disorder have an impact on self-ratings of personality with special consideration of potential differences between diagnostic groups. 90 recovered DSM-III-R major unipolar depressives and 167 recovered bipolars were compared with respect to scale values of the Munich Personality Test (MPT). Major depressives showed significantly higher scores on the MPT scales Rigidity and Orientation towards Social Norms, and lower scores on Extraversion than the bipolar patients. Using a LISREL-model, psychopathology was found to have a significant impact on Neuroticism and Extraversion, but not on Rigidity and on Orientation towards Social Norms. Controlling for symptomatology, the differences in the MPT scale values of the two diagnostic groups remained significant and can hardly be sufficiently explained by residual symptomatology.

Adult↗

PubMed1997

Flow injection photometric determination of zinc and copper with zincon based on the variation of the stability of the complexes with pH.

A flow injection photometric method for the sequential determination of zinc and copper in mixtures was developed based on the variation of the stability of the chromogenic complexes between the analytes and the reagent zincon with pH. At pH 5.0 only the Cu-zincon complex exists, whereas at pH 9.0 the copper and zinc chelates co-exist. A three-channel manifold was implemented containing two alternating buffer streams (pH 5 and 9) which permit the colored reaction products to be formed sequentially at both pH values, and consequently the mixtures can be resolved. A continuous preconcentration unit (Chelex-100) was used in order to increase the sensitivity of the method, thus allowing the analysis of water samples in which the analytes are present at the ng ml-1 level. On the other hand, preconcentration was not required when the analytes were determined in brass. Under the optimum conditions and using a preconcentration time of 2 min, the detection limits (3 sigma) were found to be 0.35 and 0.80 ng ml-1 for zinc and copper, respectively. The repeatability of the method, expressed as the RSD, was in all instances less than 3.1%. Considering the sequential determination of both species, a sampling rate of 70 h-1 was obtained if preconcentration of the samples was not required.

Azo Compounds↗

PubMed1997

Measuring treatment outcome by the Beck Depression Inventory.

The construct validity of the Beck Depression Inventory (BDI) in measuring treatment outcome is assessed in 103 psychiatric inpatients. In this context, construct validity means that the BDI measures the same construct in repeated measurement and that the change scores can be explained by treatment effects. In confirmatory factor analyses, only the first factor proved to be stable. In accordance with other studies, the sensitivity to therapeutic change in long-term intervals of several weeks could be confirmed. Significant changes in a short-term interval of 1 day in the non-endogenously depressed patients indicate an overreactivity of the BDI to change which cannot be explained by treatment effects or mood changes.

Adjustment Disorders↗

PubMed1997

Recidivism and concomitant criminality in pathological firesetters.

The purpose of this study was to explore dangerousness and fire setting recidivism of mentally disordered firesetters in comparison with mentally healthy arsonists. In Germany, all trials are registered centrally by the Federal Central Register. The records of this Register for the three year period from 1983 until 1985 were used in this follow-up study of arsonists to identify three samples of subjects: (1) All persons convicted of arson who have been found not guilty by reasons of insanity (n = 186), (2) all person convicted of arson who have been found guilty of diminished responsibility (n = 97), and (3) a random selection from all persons convicted of arson who have had no psychiatric examination in their trial (n = 187). The follow-up ended in 1994, providing a period of, on average, ten years. Mentally disordered arsonists differed from non-mentally disordered arsonists in the following ways: They were more likely, first, to have a history of arson before 1983, and secondly, to be convicted of arson again (11% relapse compared to 4%). Mentally disordered arsonists had fewer registrations of common offenses, such as theft as well as traffic violations and alcohol-related offenses. Based on the present sample, mentally disordered firesetters have a higher rate of recurrence of firesetting than non-mentally disordered firesetters and commit fewer common offenses other than firesetting.

Adolescent↗

PubMed1996

Stereoselectivity of lipases in supercritical carbon dioxide. I. Dependence of the regio- and enantioselectivity of porcine pancreas lipase on the water content during the hydrolysis of triolein and its partial glycerides.

The stereoselectivity of porcine pancreas lipase (PPL) was investigated during the enzymatic hydrolysis of triolein and its partial glycerides in the presence of supercritical carbon dioxide (SCCO2) as reaction medium. The water content of the immobilized lipases was varied. The partial glycerides were separated into mono- and diglycerides by TLC, converted to their 3,5-dinitrophenylurethane derivatives and subsequently resolved into sn-1,2 and sn-2,3 enantiomers (estimation of dioleins) or into sn-1 and sn-3 enantiomers (estimation of monooleins) by HPLC on a chiral stationary phase (Sumichiral OA-4100). In all reactions under the conditions employed, PPL revealed a distinct preference for the sn-3 position of the glycerol. However, the stereoselectivity depends on the reaction time, the substances initially used and the enzyme water content. It seems that the effect of the enzyme water content on the activity and selectivity of porcine pancreas lipase in SCCO2 is based on a modification of the "micro-environment' of the enzyme by the solution of CO2 in water, causing a decrease of the pH value.

Animals↗

PubMed1996

[Tolerance of ambiguity in endogenous psychoses from the transcultural viewpoint].

This study tries to determine the relationship between intolerance of ambiguity and different psychiatric disorders classified according to DSM-III-R criteria in two different countries. Inpatients from the psychiatric department of the Universidad de Chile and the psychiatric department of the University of Heidelberg (Germany) with uniplar, bipolar or schizophrenic disorders, as well as normal controls in both cultures completed the Kischkel Intolerance of Ambiguity Scale. The group of unipolar depressive inpatients showed significantly higher scores in both samples. Among the Chilean schizophrenic patients, differences between unipolar and bipolar disorders were seen only in the Chilean sample. Differences between unipolar depressive and schizophrenic patients were evident in the German sample only. The psychopathological and nosological significance of these findings in unipolar depressives is discussed.

Adult↗

PubMed1996

Forecasting recidivism in delinquency by intelligence and related constructs.

In a longitudinal survey of 122 healthy criminal offenders aged 18 to 37 years, the relationship between intelligence measured by the Wechsler Adult Intelligence Scale (WAIS), neuropsychological scales and delinquency was investigated. The Benton Test correlates well with the WAIS and moderately with offence data, but not with recidivism in delinquency. The 122 men had normal intelligence test scores (average IQ = 102), but bad school and working records. The 34 per cent and 60 per cent respectively of offenders, who relapsed within the time span of 1.5 and 3 years respectively, showed significantly worse results in the Verbal Scale and in the Block Design of the Wechsler Intelligence Scale. Poor performance in the Information and the Block Design sub-tests of the WAIS, a low level of formal education and the belief in external control by circumstances and powerful others are predictors of a high risk of recidivism.

Adolescent↗

PubMed1996

[Primary and secondary negative symptoms: a useful differentiation? An empirical study].

The concept of schizophrenic negative symptomatology consisting of primary, treatment-resistant negative symptoms associated with cognitive dysfunction and treatable secondary composite negative symptoms was tested by comparing a group with non-chronic schizophrenia and a neurotic group with negative symptoms before and 8 weeks after the start of treatment. Contrary to our hypothesis, we found no association between schizophrenic negative symptoms and cognitive dysfunction as measured by CPT and K-V-T either at the first or at the second assessment point, but did find a strong relation between depressive and negative symptomatology at both assessment points in both groups. Thus, we conclude that a chronic course, rather than primary negative symptomatology, may be associated with cognitive dysfunction. The concept of primary negative symptoms based on cognitive dysfunction versus secondary negative composite symptoms encompassing motivation and reactive attitudes is not supported by these results.

Adult↗

PubMed1995

Differential mutagenicity and cytotoxicity of (+/-)-benzo[a]pyrene-trans-7,8-dihydrodiol and (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide in genetically engineered human fibroblasts.

DNA repair-deficient (xeroderma pigmentosum group A (XPA)) and DNA repair-proficient (normal) human skin fibroblasts were genetically engineered by transformation with a controllable human cytochrome P450 (CYP)1A1 expression vector. Induction of CYP1A1 enabled these cells to metabolize (+/-)-benzo[a]pyrene-trans-7,8-dihydrodiol (BPD) into a potent cytotoxicant and mutagen. The XPA cells were more susceptible than the normal cells to the cytotoxic effects of both CYP1A1-metabolized BPD and exogenously supplied (+/-)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10- epoxide (BPDE). Furthermore, the differential cytotoxicity between XPA and normal cells induced by CYP1A1-metabolized BPD was 8.4-fold greater than that induced by exogenously supplied BPDE. The two cell lines had similar CYP1A1 activities, suggesting that a difference in metabolic potential was not the cause of the differential response to BPD. At comparable cytotoxicity in both XPA and normal cells, BPD treatment induced more mutants and more DNA adducts than BPDE treatment did. At similar levels of DNA adducts in XPA cells, the levels of cytotoxicity induced by CYP1A1-metabolized BPD and exogenously supplied BPDE were similar, but CYP1A1-metabolized BPD induced a threefold higher hypoxanthine phosphoribosyltransferase mutation frequency. In contrast, at similar levels of adducts in CYP1A1-expressing normal cells, BPD induced less cytotoxicity and a lower mutation frequency. DNA adducts were identified and quantified by 32P-postlabeling analyses. The principal adduct formed by both CYP1A1-metabolized BPD and exogenously supplied BPDE was 10-beta-(deoxyguanosin-N2-yl)-7 beta,8 alpha,9 alpha-trihydroxy-7,8,9,10- tetrahydrobenzo[a]pyrene, indicating that the differential effects of BPD- and BPDE-induced adducts were not due to a difference in the types of adducts formed. The results of these studies suggest that CYP1A1-metabolized BPD may form adducts preferentially in transcriptionally active genes or that the intracellular concentration of BPDE may influence the balance between cytotoxicity and mutagenicity (or both).

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed1995

Changes in salivary [K+], [Na+] and [K+]/[Na+] with varied test demands.

It was hypothesised that choice reaction-time (CRT) testing would cause salivary [K+]/[Na+] to increase. Relative contributions of [K+] and [Na+] to ratio changes were investigated in 23 hypertensives and ten hospital staff. Changes in post-rest and post-test ionic concentrations and [K+]/[Na+], replicated earlier studies. Phasic [K+]/[Na+] changes were mainly due to [K+] changes. Significant increases in [K+] and decreases in [Na+] from a relaxed session, the day before CRT testing, to the testing session per se indicated test anticipation effects. In both groups, changes from pre-test "rest" to "on test" were significant only for [K+]. [K+] discriminated well between conditions in hypertensives. This was interpreted in terms of adaptive changes in sympathetic activation. Results show the robustness of salivary ion indices (especially of [K+]) as indicators of within-subject response to mental task demands.

Adult↗

PubMed1995

Metabotropic glutamate receptor subtypes differentially influence neuronal recovery from in vitro hypoxia/hypoglycemia in rat hippocampal slices.

Hippocampal slices were transiently exposed to an oxygen- and glucose-free environment which causes a pronounced drop of both ATP and creatine phosphate, an anoxic depolarization, and an incomplete recovery of synaptically evoked population spike in the CA1 region after 1 h (48.5 +/- 3.6% of baseline values). This recovery could be markedly enhanced by the application of N-methyl-D-aspartate receptor antagonists. To examine the influence of metabotropic glutamate receptors on neuronal recovery from hypoxia/hypoglycemia, we applied various antagonists and agonists of the metabotropic glutamate receptors to the bath during the interval from 20 min before to 10 after hypoxia/hypoglycemia. The metabotropic glutamate receptor antagonists (+)-alpha-methyl-4-carboxyphenylglycine and L-2-3- amino-phosphonopropionic acid were both able to enhance the population spike recovery significantly. However, the mixed metabotropic glutamate receptor agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid also exhibited a protective effect on population spike recovery, leaving the anoxic depolarization and N-methyl-D-aspartate responses during the hypoxia/hypoglycemia untouched. With the help of more subtype-specific agonists, we found that an activation of phospholipase C coupled (class 1) metabotropic glutamate receptors prior to hypoxia/hypoglycemia may be responsible for the protective effect seen with 1S, 3R-1-aminocyclopentane-1,3-dicarboxylic acid, because the specific class 1 metabotropic glutamate receptor agonist trans-azetidine-2,4-dicarboxylic acid appeared to be highly protective, but only if it was applied 20 min before the hypoxia/hypoglycemia. An activation of class 2 metabotropic glutamate receptors by (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine, which inhibits adenylyl cyclase activity, led to a marked deterioration of the population spike recovery and even to a total prevention of the protective effect of the N-methyl-D-aspartate agonist D-2-amino-5-phosphonopentanoic acid. Our data suggest that prior activation of class 1 metabotropic glutamate receptors is beneficial, while their activation during hypoxia/hypoglycemia is detrimental. Furthermore, the activation of class 2 metabotropic glutamate receptors decreases the recovery from hypoxia/hypoglycemia.

Adenosine Triphosphate↗