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Biomedical subjects

J Richter

Publications and source records attributed to J Richter.

At least 271 records · Page 15Linked to original sources
PubMed1991

Perceived parental rearing and state versus trait aspects of adult depression.

In a pilot study of 72 psychiatric inpatients, relationships between state versus trait aspects of depression and perceived parental rearing have been investigated. It appeared that trait aspects (assessed by the mood scale of the Giessen test) yielded the most frequent and highest correlations with the factors rejection, emotional warmth and overprotection of the EMBU (Egna Minnen av Barndoms Uppfostran--My Memories of Upbringing) questionnaire of parental rearing. Particularly rejecting maternal rearing behaviour during childhood seems to constitute a risk factor for the development of trait depression during adulthood.

Depressive Disorder↗
PubMed1991

[Photon-emission tomography (SPECT) in the detection of hepatic hemangiomas of small size].

By means of ultrasonography it is possible to detect hepatic lesions of few millimeters, however, it doesn't give a precise diagnosis. The role of planar scintigraphy in the diagnosis of hepatic hemangioma has already been established, although it has limitations which are partially solved by means of SPECT. 46 patients with different pathologies and 9 healthy volunteers have been studied. In the 19 confirmed hemangiomas, planar scintigraphy showed a sensitivity of 73.6% versus 84.2% for SPECT, mostly due to lesions less than 2.5 cm. Besides that, SPECT allowed a correct visualization of abdominal and intrahepatic major vessels, although lesions less than 1.5 cm are difficult to evaluate.

Adult↗
PubMed1991

[Assessment of radiotherapy plans: dose-volume histograms, integral effects and tumor control].

Suitable criteria are necessary for judgement and for comparison of treatment plans. These criteria must take into account radiobiological effects, i.e. tumor control and treatment complications. Quantitative evaluation of dose volume histograms gives helpful criteria for radiation treatment planning and for the choice between different treatment plans. For normal tissue and organs at risk it is shown, how to assign integral dose effect to inhomogeneous dose distribution. The evaluation algorithm is based on the assumption of a power law for volume dependence of dose effect. The algorithm is discussed for arbitrary form of dose effect function. Explicit evaluation is given in terms of the linear quadratic model. Hot spots influence integral dose effect much stronger than low dose level irradiation. For judgement of treatment plans, the significance of mean organ dose is only poor. Higher moments of dose distribution are more suitable. An effective tumor control probability is derived for judgement of tumor dose distribution. It is shown that tumor control is determined by mean dose and dose inhomogeneity in tumor volume. Control probability falls with increasing dose inhomogeneity in tumor region-in first order approximation characterized by variance of dose distribution. Using a clinical example, the evaluation rules for normal and tumor tissue are demonstrated. Two different treatment techniques are analyzed and discussed. Only numerical evaluation of dose volume histograms for lung region shows the better technique.

Algorithms↗
PubMed1991

[Quality assurance in dynamic radiotherapy techniques].

Compared with conventional radiation treatment techniques, quality assurance for dynamic techniques has to consider additionally the variability of the movement parameters of the treatment unit. In this context the exactness and the reliability of the computer control are of special interest. In this paper the results of quality assurance for dynamic treatment techniques are reported. At first investigations concerning the reproducibility are carried out. Another test is the simulation of conventional moving beam techniques by external computer control. Further the differences between measured dose distributions of dynamic techniques and the distributions resulting from the sequence of fixed fields approximating these techniques are determined. Finally we compared measured and calculated dose distributions. The results of the investigations justify the introduction of dynamic radiation treatment techniques into clinical use.

Humans↗
PubMed1991

[The new Würzburg data bank for radiotherapy].

Conception, structure and realisation of a new data base for radiation therapy are presented. The data base utilizes the commercial data base system ORACLE and the data base language SQL. A program package for statistical analyses including Kaplan-Meier-calculations, logrank test and Gehan/Breslow test was elaborated. The input of the data recorded on form sheets is carried out on a data base of the Tumor Centre in the first instance. From there the data are transferred to the ORACLE data base. Up to now the courses of disease of about 13,000 patients are stored. Therefore, extensive and detailed statistical analyses are practicable.

Databases, Factual↗
PubMed1990

Correlation between spontaneous oscillations of cytosolic free Ca2+ and tumor necrosis factor-induced degranulation in adherent human neutrophils.

By using a hemolytic plaque assay to detect release of lactoferrin and myeloperoxidase, tumor necrosis factor (TNF) was shown previously to induce secretion of these granule proteins from single adherent neutrophils. Secretion was inhibited by loading neutrophils with calcium chelators, indicating a crucial role of cytosolic free [Ca2+] in the signal transduction mechanism of TNF. In the present study, using a microfluorometer technique to follow changes in the cytosolic free [Ca2+] in single adherent neutrophils, we were not able to detect any TNF-induced [Ca2+] transients. However, these adherent cells exhibited spontaneous oscillations of their cytosolic free [Ca2+], as previously reported (Jaconi, M.E.E., Rivest, R.W., Schlegel, W., Wollheim, C.B., Pittet, D., and Lew, P.D. (1988) J. Biol. Chem. 263, 10557-10560). A close correlation was found between a reduced oscillatory activity of cytosolic free [Ca2+] and a reduced ability of TNF to induce degranulation, by reducing the extracellular [Ca2+] or loading the cells with a calcium chelator (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid). In addition, when the cells were incubated at 37 degrees C for 3 h there was a parallel decline in the spontaneous oscillatory activity of cytosolic free [Ca2+] and TNF-induced secretion of lactoferrin. Control experiments showed that phorbol 12-myristate 13-acetate-induced secretion was not affected under the same conditions, indicating that the secretory process per se was not disturbed. We conclude that TNF by itself does not give rise to any changes of the cytosolic free [Ca2+] but that the spontaneous oscillatory activity of cytosolic free [Ca2+] in adherent neutrophils is necessary for TNF-induced degranulation.

Calcium↗
PubMed1990

[The role of immunology in monitoring the effects of environmental pollution].

The paper gives a neat summary of experience acquired from two decades of immunological testing methods used for studying the effect of environmental contamination of the human organism. Immunological examination is part of a series of methods for a systematic follow-up of the state of health of the population. The paper underlines the complicated process leading to the resulting individual immune reactivity, which can be regarded as an outcome of multilateral interaction between the immune genetically conditioned potential and external environmental influences.

Environmental Health↗
PubMed1990

[X chromosome-linked lymphoproliferative syndrome (Duncan's disease)].

The authors describe two cases of fatal disease with the picture of acute haemoblastosis in male siblings aged 6 and 18 months. By combined retrospective evaluation of the two cases the authors reach the conclusion that it is the first case of an X chromosome-linked lymphoproliferative syndrome (XLP) described in Czechoslovakia. The authors discuss laboratory and clinical findings (dynamic of specific antibodies against EBV, histopathological finding, clinical evaluation, hypergammaglobulinaemia IgM, paraprotein IgM, genetic examination) and evaluate the disease as the proliferative form of XLP in the clinical variant of fatal infectious mononucleosis. The paper provides also some basic information on XLP, incl. some new findings.

Antibodies, Viral↗
PubMed1990

[Intradermal method of vaccination with a human diploid cell tissue culture vaccine for preexposure antirabies immunization].

The authors provide evidence of seroconversion in 16 subjects (100%) following intradermal administration of antirabies vaccine from a tissue culture of human diploid cells [Rabivac, Behring, FRG] for the purpose of pre-exposure immunization. The immunomodulating preparation Levamisol [Decaris Richter, Hungary] did not influence the mean antibody titre during administration by the intradermal route.

Adult↗
PubMed1990

Lymphotoxin induces secretion of granule proteins from adherent neutrophils: possible role of intracellular free calcium.

Lymphotoxin (LT) can activate human neutrophils. Using a hemolytic plaque assay to detect secretion of lactoferrin and myeloperoxidase (MPO) from single adherent neutrophils, we showed that LT induced secretion from both primary and secondary granules. Incubation of cells with cytochalasin B was required for MPO secretion, and it enhanced lactoferrin secretion. Pertussis toxin, which blocks a G-protein in the plasma membrane, inhibited LT-induced exocytosis of MPO, but not of lactoferrin. Incubation with LT did not induce any detectable changes of the cytoplasmic free [Ca2+] in neutrophils. On the other hand, secretion of granule proteins from adherent neutrophils in response to LT was blocked by loading neutrophils with quin-2 in order to increase the intracellular calcium buffering capacity. This was achieved at a concentration of quin-2, at which the secretion induced by the phorbol ester PMA and the chemotactic peptide FMLP was unaffected. Trifluoroperazine (TFP), a dual protein kinase C and calmodulin inhibitor, significantly inhibited the LT-mediated secretion of lactoferrin from adherent granulocytes. The PMA effect was unaltered by TFP under these conditions, suggesting that the inhibitory effect was on a calcium-calmodulin dependent step. The secretion induced by TNF and GM-CSF was also blocked by buffering changes in the intracellular [Ca2+] and inhibited to a similar extent by TFP. Our results suggest that calmodulin and minute changes in the cytoplasmic free [Ca2+] may be involved in a common signal transduction pathway engaged in activation of adherent neutrophils by several cytokines.

Calcium↗
PubMed1990

Changes in auditory evoked brain potentials during ultra-low frequency whole-body vibration of man or of his visual surround.

Auditory evoked brain potentials (AEP) were recorded from nine healthy male subjects during three types of condition: A - subject and visual field stationary; B - subject vibrated (z-axis, 0.6 Hz, 1.85 ms-2 rms), visual field stationary; C - subject stationary, visual field vibrated (as for B). The visual surround was confined to a checkerboard pattern in front of the subject. Auditory stimuli (1000 Hz, 86 dB, interstimulus interval 7 s) were delivered via headphones to evoke AEP. Vibration-synchronous activity in the EEG was eliminated by a subtraction technique. In comparison with condition A, conditions B and C caused an attenuation of P2 and N1P2 components of AEP together with an increased latency of N1. Effects of conditions B and C did not differ. Direct vestibular stimulation and mechanisms specific for whole-body vibration were rejected as modes of action. The AEP-changes and the subjective evaluation of experimental conditions, arousal and performance, as well as symptoms of kinetosis (motion sickness) suggest a sensory mismatch, leading to a "latent kinetosis" with de-arousal, as the dominating mechanism by which the processing of information was affected. This suggestion was supported by an additional pilot study. Under real working conditions a similar effect can be expected during relative motion between the driver and his visual surround, i.e. even with perfect vibro-isolation of the driver's seat.

Adult↗
PubMed1990

201Tl myocardial perfusion in the management of the transplanted heart.

A semi quantitative method with thallium has been applied in the management of cardiac transplants. In all, 142 scans were performed in 20 patients and were arranged in 3 groups that represent respectively all controls performed to the transplants (G1), and a selection of the scans obtained during the 1st rejection episode in each patient (G2) and the 2nd if present (G3). A heart/lung index was calculated through early and late images (IA, IB), obtained 5 min and 4 h post injection of thallium. A decrease in IA was detected during acute rejection in all groups. This fall was statistically significant from the mild to moderate rejection degree in G1 (P less than 0.01), and the mild rejection in G3 (P less than 0.001). IB was not modified with rejection. Comparing the biopsies with and without edema, in the absence of rejection, it has been proved that the intra myocardial edema can produce a decrease in IA (P less than 0.001). We conclude that IA is a simple and sensitive index to evaluate the graft, although intra myocardial edema can reduce its specificity.

Coronary Circulation↗
PubMed1990

The surface to volume ratio of mitochondria, a suitable parameter for evaluating mitochondrial swelling. Correlations during the course of myocardial global ischaemia.

Cellular changes occurring in the left ventricular myocardium during ischaemia after different methods of cardiac arrest have been evaluated by morphological and morphometric parameters: volume densities of mitochondria (VVMi), sarcoplasm (VVSp), myofibrils (VVMf), surface densities of mitochondria (SVMi). The surface to volume ratio of mitochondria (SVratioMi) has been used as an independent parameter of mitochondrial swelling. Since ischaemic swelling of myocardial cells increases the volume of the reference space and ischaemic swelling of mitochondria decreases the free sarcoplasm, VVMi and VVSp cannot be considered as reliable indicators of the degree of oedema. SVMi/VVMf remains nearly constant after different forms of cardiac arrest, demonstrating the integrity of mitochondrial outer membranes. The inverse linear ratio between SVratioMi and the mean mitochondrial volume indicates that the increase in mitochondrial volume is achieved by surface smoothing. Loss of matrix structure and fragmentation of cristae occur at an SVratioMi of about 5.8, cristolysis at 5.5 to 5.6 and amorphous matrix densities at an SVratioMi of less than 5.5 micron2/micron3. The SVratioMi is a suitable parameter for evaluating mitochondrial swelling both at the onset and during global myocardial ischaemia, independent of the method of cardiac arrest used. It serves as an indicator of the state of structural preservation of mitochondria during ischaemia.

Animals↗
PubMed1990

Ultrastructural effects induced by global ischaemia on the AV node compared with the working myocardium. A qualitative and morphometric investigation on the canine heart.

The cardiac conduction system is considered to be particularly resistant to ischaemia. Nevertheless, following open heart surgery with short periods of ischaemia disturbances in AV conduction or ventricular arrhythmia have been reported. We compared the ultrastructure of AV node and working myocardium following 30 min global ischaemia at 25 degrees C, during pure ischaemia and with HTK cardioplegia qualitatively and morphometrically. After 30 min of pure ischaemia, interstitial and intracellular oedema together with considerable changes in organelles in AV nodes predominate over mainly cellular oedema in working myocardium. Sometimes irregular overcontractions of sarcomeres occur in the AV node, though very seldom in working myocardium. In pure ischaemia, mitochondrial swelling is comparable in both types of tissue. Following HTK cardioplegia and 30 min ischaemia, cellular oedema and mitochondrial swelling are significantly reduced in AV nodal cells and working myocardium, but remain more extensive in the AV nodes. Irregularities in the contractile state of sarcomeres are not observed. The extent of the ultrastructural alterations corresponds to the degree of metabolic change in the working myocardium. Thus, despite considerable differences during pure ischaemia and HTK cardioplegia, ultrastructurally the AV nodal cells do not display a greater resistance to ischaemia than working myocardium.

Animals↗
PubMed1990

Occurrence and prevention of contraction bands in Purkinje fibres, transitional cells and working myocardium during global ischaemia.

Contraction bands usually occur in the intramural working myocardium following post-ischaemic reperfusion. In the subendocardium, however, they are found during ischaemia. Thus, we ascertained the contraction states of Purkinje fibres, transitional cells, subendocardial and intramural parts of the working myocardium during 30 min global ischaemia at 25 degrees C. The effects with and without myocardial protection were compared. At the onset of pure ischaemia contraction bands are completely lacking in all cell types. During pure ischaemia contraction bands are found in all subendocardial cell types but not in the intramural working myocardium. A peak of pathological contraction states is found in the intramural working myocardium at the onset (0 min), in the subendocardial working myocardium at 10 min, in the transitional cells and Purkinje fibres at 30 min of pure ischaemia. Histidine-, tryptophan-, ketoglutarate-enriched (HTK) cardioplegia prevents contraction bands completely at the onset of ischaemia and prevents both contraction bands and pathological contraction states during ischaemia almost completely. Striking differences in the physiological contraction states are seen only in the working myocardium: HTK cardioplegia brings about dominance of relaxation during ischaemia. These findings may be due mainly to the effects of global ischaemia on the one hand and to catecholamines, calcium and oxygen on the other.

Animals↗
PubMed1990

Tumor necrosis factor-induced degranulation in adherent human neutrophils is dependent on CD11b/CD18-integrin-triggered oscillations of cytosolic free Ca2+.

We have recently been able to correlate closely the "spontaneous" oscillatory activity of cytosolic free Ca2+ in adherent human neutrophils with the ability of tumor necrosis factor (TNF) to induce secretion of granule proteins from these cells. In the present work we show with a single-cell technique that preincubation of human neutrophils with antibodies to CD18, the common beta chain of leukocyte adhesion proteins, inhibits TNF-induced secretion of lactoferrin in a time- and concentration-dependent manner. Similar effects of CD18 antibodies were found on chemotactic factor (fMet-Leu-Phe)- but not on phorbol 12-myristate 13-acetate-induced secretion, suggesting that cell-surface-receptor-mediated secretion is dependent on integrin-associated signals. Similarly, antibodies to CD11b (alpha chain of macrophage 1) also inhibited TNF- and fMet-Leu-Phe- but not phorbol 12-myristate 13-acetate-stimulated release of lactoferrin. Antibodies to CD11a (alpha chain of lymphocyte function-associated antigen 1) or CD11c (alpha chain of p150,95) had only a minimal effect on agonist-induced secretion. Data obtained in several laboratories, including our own, made us suspect that integrin interaction with the surface is responsible for the oscillatory activity of cytosolic free Ca2+ in adherent cells. Indeed, preincubation with antibodies to either CD18 or CD11b, but not to CD11c, inhibited the oscillations of cytosolic free Ca2+ in adherent neutrophils. This inhibitory effect was evident both as a reduction of the number of responding cells and as a reduction of the oscillatory activity in the cells. In conclusion, the oscillatory activity of cytosolic free Ca2+ in adherent neutrophils is mediated through the CD18/CD11b integrins. The generation of this Ca2+ signal may explain how adherence, by way of the integrins, changes the functional properties of the cell and enables TNF to induce secretion.

Antibodies, Monoclonal↗
PubMed1990

Altered generation of interleukin 1 in chronic human schistosomiasis mansoni.

Chronic schistosomiasis mansoni is associated with impaired cell-mediated immune responsiveness (CMI). To assess co-stimulatory factors essential in the induction phase of CMI, interleukin 1 (IL-1) concentration was determined in the sera and cell culture supernatants of Schistosoma mansoni-infected patients, and circulating monocytes were phenotyped, labelling membrane IL-1 and HLA-DP. In addition, adherent cell oxidative-burst capacity was investigated. Since involvement of IL-1 beta in the pathogenesis of severe granulomatous lesions could not be ruled out, 17 patients with intestinal schistosomiasis and 17 patients with hepatosplenic schistosomiasis were matched for intensity of infection and monitored 3-6 months after praziquantel therapy. Seventeen age- and sex-matched uninfected residents of the study area in Alagoas, Brazil, acted as controls. Whereas schistosomiasis patients and controls did not differ in the expression of monocyte surface antigens and the capacity of adherent cells to generate H2O2, IL-1 beta release by monocytes in vitro was significantly reduced in both intestinal and hepatosplenic patients. Low concentrations of circulating IL-1 beta were detected in comparable frequencies in untreated patients and controls. Three months after therapy, IL-1 beta was detectable in serum in an increased proportion of intestinal schistosomiasis patients. IL-1 release in vitro gradually increased in all patients and reached control values 6 months after therapy.

Adolescent↗