Search PubMed⌕ Search

Biomedical subjects

M Richter

Publications and source records attributed to M Richter.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Severe vomiting, diarrhea].

Because of heavy vomiting and a watery diarrhoea after consumption of two Amanita phalloides mushroom taken in suicidal attempt this 31-year old female patient came to our emergency ward. The diagnosis being clear a therapy with stomach irrigation, substitution of fluid and electrolytes as well as application of penicillin and Silibinin was begun. The toxin concentration in the urine was not too high and the Quick value did not fall to low. The course was benign and the patient could leave the hospital only a few days later.

Adult↗
PubMed1990

Immunodeficiency following splenectomy in the early postimmunization period.

Splenectomy is associated with an increased risk of serious infection with encapsulated micro-organisms in a small number of individuals. The immunological defects in this state are unclear. We have investigated in rabbits the effect of splenectomy, before and after primary immunization with a specific antigen (sheep erythrocytes) similar in structure to the pneumococcal capsular antigen, on the organ localization of antibody forming cells and the long-lived memory cells. Antibody forming cell and memory cell assays were performed at intervals up to day 270 after primary immunization. Antibody titres following secondary immunization were also measured. The results show that the major site of antibody forming cells is in the spleen following primary immunization of the untreated rabbit and that antibody forming cells subsequently migrate to the lymph nodes and thymus. On the other hand, in rabbits splenectomized before primary immunization the major site of the antibody forming cells is the peripheral lymph nodes. These rabbits also gave good secondary immune responses. However, splenectomy 40 days after primary immunization results in a poor secondary immune response, indicating that essentially all the antibody forming cells following primary immunization were localized in the spleen at the time of splenectomy.

Animals↗
PubMed1990

Surface receptors and immune activity of purified human circulating mononuclear cells. V. Circulating null cells and a factor secreted by the null cells inhibit the synthesis of receptors for Fc mu by T cells in culture.

Receptors for Fc mu (Fc mu R) were not detected on freshly isolated unfractionated circulating human mononuclear cells (MNC) or purified T cells. However, a significant percentage of the T cells (20% to 40%), but not of the unfractionated MNC, exhibited Fc mu receptors following culture for 24 h at 37 degrees C in medium enriched with fetal calf serum. These receptors were newly synthesized by the T cells since they were not detected on T cells cultured for 24 h with cycloheximide in a non-cytotoxic concentration. The absence of Fc mu R on the cultured unfractionated MNC (of which 70% are T cells) suggested that non-T cells within the MNC-B cells and/or null cells and/or monocytes suppressed the synthesis of Fc mu R by the T cells. These cells were individually assayed for their capacity to suppress Fc mu R synthesis by co-cultured T cells. The null cells were able to totally suppress Fc mu R synthesis whereas the B cells and monocytes exhibited no suppressive activity. Null cells cultured for 24 h at 37 degrees C secreted a factor which inhibited the synthesis of receptors for Fc mu by the cultured T cells. This factor is referred to as receptor synthesis suppressor factor or RSSF. On the basis of these findings, it is concluded that (a) the circulating T cells do not possess Fc mu R; these receptors are synthesized de novo by the T cells in culture, (b) the null cells, but neither the B cells nor the monocytes, suppress the synthesis of the Fc mu R by the T cells and (c) the null cells, but neither the B cells nor the monocytes, secrete a factor, receptor synthesis suppressor factor, which can suppress the synthesis of Fc mu R by the T cells.

Cells, Cultured↗
PubMed1990

Cells and mediators which participate in immunoglobulin synthesis by human mononuclear cells. II. The mechanism of null cell participation in immunoglobulin synthesis and secretion by B cells.

Immunoglobulins were synthesized and secreted by human B cells cultured with T cells with receptors for FcM (TM) helper cells, monocytes, null cells and PWM for 7 days. Immunoglobulin synthesis did not take place if the null cells were omitted from the cultures irrespective of the duration of the culture period. Null cells incorporated into the cultures at only 25% of their optimal concentration did not affect immunoglobulin synthesis markedly by the cultured B cells. However, the number of B cells in the culture could not be diluted without an accompanying marked reduction in immunoglobulin synthesis. The B cells synthesized and secreted significant quantities of immunoglobulin even when the null cells were added as late as day 6 of the 7-day culture whereas no or very little immunoglobulin was synthesized if the B cells were not present from the beginning of the 7-day culture. It was demonstrated that cultured null cells do not transform into B cells and do not attain their immunoglobulin-synthesizing function. Furthermore, cultured B cells do not transform into null cells and do not attain their helper function. The null cells can also be distinguished from the B cells on the basis of cell-surface markers, receptors, and blastogenic responsiveness to phytomitogens. It is concluded that (i) the human circulating B cells require the null cells, in addition to the TM cells, monocytes and PWM, in culture in order to synthesize and secrete immunoglobulin; (ii) the null cell signal that stimulates immunoglobulin synthesis and secretion by the B cells is probably the last signal following the TM helper cell, monocyte and PWM signals received by the B cells; and (iii) the null cells and the B cells constitute distinct lineages of cells.

B-Lymphocytes↗
PubMed1990

Cells and mediators which participate in immunoglobulin synthesis by human mononuclear cells. III. Null cells secrete a factor(s) (human immunoglobulin synthesis/secretion-facilitating factor) that can replace the null cells in the synthesis of immunoglobulin by cultured B cells.

In the accompanying communication, it was demonstrated that the null cells, the TM cells, monocytes and PWM are all obligatory participants in the synthesis and secretion of immunoglobulins by human B cells in culture. Here we demonstrate that the null cells secrete a factor, referred to as human immunoglobulin synthesis/secretion-facilitating factor (HISFF) that can replace the null cells in the cultures. HISFF is distinct from the known T cell-derived interleukins. HISFF functions in an HLA-unrestricted fashion since it can facilitate the synthesis and secretion of immunoglobulins by allogeneic B cells. The null cells cultured with TM helper cells and PWM required monocytes in the culture in order to secrete HISFF. Furthermore, B cells cultured with TM cells in medium containing HISFF, monocyte-derived factors and PWM nevertheless required monocytes in order to respond to the HISFF signal. Thus, the monocyte plays a pivotal role in the secretion of and response to HISFF. Normal levels of immunoglobulin were synthesized even when HISFF was added to the cultures of B cells, TM cells and monocytes, in the presence of PWM, as late as day 6 of the 7 day culture. We conclude that the null cells participate in immunoglobulin synthesis by the B cells by secreting a soluble mediator, HISFF, capable of replacing the null cells in the culture; and that the HISFF signal is the last signal received by the B cell before it begins to synthesize and secrete immunoglobulins.

B-Lymphocytes↗
PubMed1990

Cells involved in the immune response. XXXVII. Antigen-specific suppressor cells, capable of secreting an antigen-specific suppressor factor, migrate from the thymus to the spleen following primary immunization.

The splenic mononuclear cells (MNC) of rabbits 7-14 and 30-48 days following primary intravenous immunization with sheep erythrocytes generated large numbers of antibody-secreting or plaque-forming cells (PFC) in secondary immune responses induced in vitro, whereas the splenic MNC obtained from rabbits 18-30 days following primary intravenous immunization generated poor secondary immune responses (few PFC) in vitro. However, these latter splenic MNC depleted of T cells consistently generated many PFC in the secondary immune response in vitro. Furthermore, the splenic MNC of rabbits thymectomized prior to day 3 following primary intravenous immunization also generated good secondary immune responses in vitro, irrespective of the time of killing post-immunization, whereas the splenic MNC of rabbits thymectomized after day 7 following primary immunization generated poor secondary immune responses in vitro. These results indicate that the depressed ability of the splenic MNC, obtained from rabbits killed between days 18 and 30 post-primary immunization, to generate significant secondary immune responses in vitro is due to suppressor T cells. The suppressor cells are referred to as immune spleen suppressor cells or ISSC. It was demonstrated that the suppression by the ISSC is antigen-specific and that the ISSC secrete an antigen-specific suppressor factor referred to as immune spleen suppressor factor or ISSF. It is concluded that the ISSC are generated in the thymus within a few days following primary immunization, that they migrate to and infiltrate the spleen between days 3 and 7 following primary immunization, and that they suppress or down-regulate further antibody synthesis via the secretion, locally of ISSF.

Animals↗
PubMed1990

Preparation of dextran-bound recombinant hirudin and its pharmacokinetic behaviour.

Recombinant desulphatohirudin was bound via lysine residues to oxidized dextrans. The hirudin-dextran conjugates inhibit thrombin like free hirudin. The Ki-values are in the same range. In rabbits and rats the pharmacokinetic behaviour following i.v. administration of these conjugates was examined in comparison to that of hirudin. The hirudin-dextran conjugates were more slowly eliminated than hirudin, the distribution volumes in steady-state were significantly reduced, and, in comparison to hirudin, 5 to 15 times larger areas under the plasma concentration-time-curves were obtained.

Animals↗
PubMed1990

[Preparation of drug containing extrusion pellets with a thermoplastic base. 2. The optimization of drug release].

The drug release can be improved by incorporation of additional auxiliary substances in extrusion pellets. The experimental results proved evidence, that especially the incorporation of calcium carbonate or polyvinylalcohol leads to an increase of the drug release. Their content must amount to 40%. In preparing thermically unstable drugs in pellets, it is necessary to prepare these products under thermically mild conditions. By using ethylene-vinyl-acetate-copolymers these unstable drugs can be incorporated in extrusion pellets.

Calcium Carbonate↗
PubMed1990

[Contribution of the treatment of discoloured teeth].

New dental materials and their combinations increase the aesthetic and functional quality of treatment. A great improvement in the aesthetic treatment of discoloured teeth is the use of dental ceramic combined with composites.

Ceramics↗
PubMed1990

[Basal cell nevus].

The main features of the nevoid basal cell syndrome, also called Gorlin-Goltz-syndrome, are basal cell nevi, jaw cysts, anomalies of the vertebras and ribs, and intracerebral calcifications. The diagnosis is often incidentally made by discovery of bilateral jaw cysts, as it was in the case of our patient and her family. The therapy is the complete enucleation of the cyst. The cavity is filled with homologous cancellous bone graft. Recurrence and little cysts are treated with the solution of Carnoy eliminating remaining microcysts.

Acetates↗
PubMed1990

[Resection and reconstruction of mandible for treatment of two rare benign tumors].

Odontogenic myxoma and particularly juvenile fibromatosis are rare benign tumors in the maxillo-facial region. The aggressive local and sometimes voluminous development of these tumors may necessitate partial mandibulectomy. Autologous bone graft from the iliac crest is the best material for mandibular reconstruction because of its functional and esthetic results. If osteosynthesis of the graft is achieved by means of internal wiring, several weeks of intermaxillary fixation are required, whereas internal rigid fixation with plate and screws allows the patient to open the mouth more rapidly.

Adult↗
PubMed1990

[Effect of pulsating electromagnetic field therapy on cell volume and phagocytosis activity in multiple sclerosis and migraine].

PEMF treatment was studied in 10 patients with multiple sclerosis and 10 patients with migraine. In both patients' groups a single treatment induced a significant rise of yeast particle uptake by blood granulocytes. The percentage of phagocytizing cells was increased in migraine patients only. In both patients' groups 20 PEMF treatments caused a reduction of particle uptake, whereas the percentage of phagocytizing cells remained unchanged. In migraine patients the opsonic capacity of serum and the mean cell volume of erythrocytes, lymphocytes and granulocytes were initially reduced, but increased during the course of 20 PEMF treatments. The biphasic changes of cell volume and phagocytic activity are interpreted as a result of counter-regulation of the organism in response to the primary PEMF effect.

Electromagnetic Fields↗
PubMed1990

[The biomechanics of space closure and its dependence on the periodontal attachment].

The biomechanics of space closure in adult patients with loss of periodontal attachment is described. In order to achieve an even force distribution in the periodontium, force was reduced and the moment to force relationship was increased. beta-TMA-T Loops of 0.016 inch x 0.022 inch and 0.017 inch x 0.025 inch cross sections were investigated. With an automatic testing device force and moment values were determined.

Adult↗
PubMed1990

Immunologic defects following trauma: a delay in immunoglobulin synthesis by cultured B cells following traumatic accidents but not elective surgery.

The immune status of trauma patients was compared with that of elective surgery patients and normal controls. The trauma patients, the elective surgery patients, and the controls were all male, aged 18 to 36 years, in previous good health and with similar Injury Severity Scores. Only one of eight immunologic activities assayed distinguished between these groups of subjects. It was observed that the synthesis and secretion of immunoglobulins (Ig) in vitro by the circulating B cells of the trauma patients was markedly impaired when compared to Ig synthesis by B cells of the elective surgery patients or controls. Furthermore, it was demonstrated that the B cells, and not the T cells, Null cells, or monocytes, were defective in the trauma patients. The results indicate that diminished Ig synthesis and secretion by the circulating B cells of the trauma patients cannot be attributed to the surgery; rather, it appears that the defects in the B cells are a direct result of the trauma.

Adult↗
PubMed1990

[I-125 labeling of human, rat, and bovine fibrinogen].

Human, rat and bovine fibrinogen were radioiodinated using a modified chloramine-T method under mild labelling conditions and with a satisfactory labelling efficiency. The 125I-human, rat and bovine fibrinogen preparations obtained met the requirements with respect to clottability, low content of 125Iodide as well as stability in vitro and in vivo. SDS-PAGE mobility demonstrated that the integrity of the fibrinogen molecule was not affected by the labelling procedure.

Animals↗
PubMed1989

[Thoracic pain].

This 32-year-old male patient came to our emergency ward because he was suffering of a painful string on his lateral thorax wall. There was no causative event in his history. Because of the clinical findings and the lacking inflammatory signs the diagnosis of Mondor's disease could be established. This selflimited disease is now generally accepted to be a thrombophlebitis of the lateral thorax veins. The disease can spread to the arm veins or the epigastric veins. The therapy is symptomatic in local application of antiphlogistic drugs.

Adult↗