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Biomedical subjects

M Richter

Publications and source records attributed to M Richter.

At least 325 records · Page 18Linked to original sources
PubMed1985

Defibrinogenation with benzoyl-batroxobin.

The B. moojeni thrombic protease, batroxobin, was acylated by 4-amidinophenyl benzoate at the active site serine hydroxyl. From the enzymatically inactive benzoyl-batroxobin, batroxobin is generated with a half-life of deacylation of about one hour. The clotting activity of benzoyl-batroxobin in plasma is recovered with deacylation. The effects of batroxobin and benzoyl-batroxobin were studied following intravenous injection in rats. Compared to defibrinogenation with batroxobin, that obtained with benzoyl-batroxobin was much retarded. Batroxobin caused microthrombosis initially, which did not develop upon injection of benzoyl-batroxobin in equivalent doses.

Acylation↗
PubMed1985

Maternal weight and pregnancy complications.

The effect of obesity alone was investigated among 16,858 women who were delivered of their infants within a 12-month period. Complete analysis was possible for 9667 patients who were divided into four weight categories and separated into two groups, with and without complications. Perinatal mortality, infant size, and the primary cesarean delivery rate were calculated for each group. Among 2597 women with antenatal complications, there was a significant increase in perinatal mortality (p less than 0.001), primary cesarean delivery (p less than 0.02), and mean infant birth weight (p less than 0.01) in the obese and the morbidly obese gravid women. Among 7070 women without antenatal complications there was a significant increase in primary cesarean delivery (p less than 0.001) and mean infant birth weight (p less than 0.01) but not perinatal mortality in the obese and the morbidly obese gravid women. Obesity alone does not appear to affect the perinatal mortality rate but it increases the likelihood of cesarean delivery in the morbidly obese patient.

Birth Weight↗
PubMed1985

Cells and mediators which participate in immunoglobulin synthesis by human mononuclear cells. I. The obligatory requirement of null lymphocytes in the synthesis of immunoglobulins in vitro.

The circulating mononuclear cells of normal adult human volunteers were fractionated into T and non-T lymphocytes. The T cells were then fractionated into TM and non-TM cells and the non-T cells were further fractionated, by both positive and negative isolation, into B cells and null cells. Culture of non-T cells, TM cells, and PWM for 7 to 8 days resulted in cytoplasmic Ig (cIg) synthesis by all B cells, as detected by immunofluorescence. However, culture of either purified B or null cells with TM cells and PWM resulted in a marked reduction (75%) of cIg-synthesizing cells. The addition of monocytes did not enhance cIg synthesis. Culture of reconstituted B and null cells with TM cells and PWM restored the capacity to synthesize cIg to the cells. It is concluded that null cells are required, as well as TM cells and PWM, for cIg synthesis by B cells.

B-Lymphocytes↗
PubMed1984

Infrared linear dichroism of oriented DNA-ligand complexes prepared with the wet-spinning method.

Oriented DNA films prepared by the wet-spinning technique have been complexed with several ligands: the anthracycline antibiotic violamycin BI, the dipeptide L-carnosine, and the oligopeptide antibiotic netropsin. The formation of the DNA-ligand complexes is accompanied by dramatic changes of the conformational flexibility of DNA. The B-A transition which occurs usually between 80% and 70% relative humidity (RH) is more or less suppressed by the ligands. Violamycin BI at a total ligand per DNA base pair ratio, rt, of approximately 0.03 and L-carnosine at rt approximately 1.5 inhibit the B-A transition of approximately 18 and approximately 0.25 base pairs per ligand molecule, respectively. Netropsin at rt = 0.2 induces a very stable B-DNA even at rather low RH (23%). The total hydration of this complex is significantly higher than for a drug-free DNA film. Netropsin-DNA complexes at rt of 0.02 and 0.01 result in an inhibition of approximately 45 base pairs per drug molecule with respect to the B-A transition.

Aminoglycosides↗
PubMed1984

[Coagulation of 125I bovine fibrinogen].

Bovine fibrinogen was labelled with 125I using the chloramine T method or the iodogen method and the clottability of the preparations was studied in vitro and in vivo. Three days after radioiodination the in vitro clottability was 82.3% (chloramine T) and 80.4% (iodogen), respectively. When the solutions were allowed to stand at 4 degrees C for 13 days, the in vitro clottability decreased to 70% or 60%, respectively; either preparation was practically unclottable after 25 days. The preparations were administered to rats three days following radioiodination. They showed the same elimination rate and, on thrombin infusion, the same clottability. 125I-labelled (chloramine T) bovine fibrinogen stored in solution at -20 degrees C for 38 days showed a clottability of 76%, the in vivo clottability was unchanged.

Animals↗
PubMed1984

[Factors influencing the in vitro and in vivo liberation of drugs from hydrogels].

Interactions of drugs containing macro-molecular agents (cellulose derivatives, polyvinylpyrrolidone) as determined by equilibrium dialyses influence on the in-vitro liberation (hydrophilic membrane) from hydrogels of the same viscosity acc. to the binding intensity. Utilizing a lipophilic membrane, this can be proved, too, the liberation intensity, however, is substantially determined by the lipoidwater distribution behaviour of the drugs. In-vivo liberations revealed in this, that differentiations in the liberation from methylcellulose and polyvinylpyrrolidone gels occur solely in drugs having a more intense affinity. The penetration intensity of the hydrogel into skin is, however, not caused by the binding tendency but by the lipoidwater distribution behaviour of the drugs. Analysing the in-vitro liberation with the use of a lipophilic membrane or knowing the distribution coefficient, informations on the level of the probable drug penetration gel/skin can be given.

Biological Availability↗
PubMed1983

Surface receptors and immune activity of purified human circulating mononuclear cells. IV. The demonstration of seven subclasses of T cells in the circulation of the normal individual: the cytotoxic activities of these cells.

T lymphocytes were isolated from monocyte-depleted mononuclear cells of normal individuals by rosetting them with sheep erythrocytes. These purified T cells were preferentially depleted of cells with receptors for FcG (TG cells), FcM (TM cells), or C'3 (TC cells) by rosette formation with EA(G), EA(M), and EAC, respectively, before or after incubation for 24 hr in medium 199 fortified with fetal calf serum (20%). The unfractionated lymphocytes and the purified and the depleted T cells were analyzed for receptors to FcG, FcM, and C'3 and for cytotoxic activity in the natural killer (NK), antibody dependent cell-mediated cytotoxicity (ADCC), and mitogen-induced cell-mediated cytotoxicity (MICC) assays. The TG and TC cells were detected among the freshly isolated T cells, whereas the TM cells were detected only following 24 hr of incubation. Removal of TC cells from the 24-hr-cultured T cells resulted in removal of all the TC cells and in the concomitant removal of the majority of TM cells. Similarly, removal of TM cells from the 24-hr-cultured T cells resulted in the elimination of all TM cells as well as the majority of TC cells. These results demonstrate the in vitro generation of T cells with receptors for both FcM and C'3 (TM+C cells). Ten percent of the freshly isolated TG cells possessed detectable receptors for C'3 and/or FcM. These cells constitute the TG+C and TG+M lymphocytes. Support for consideration of these receptor-bearing cells as unique and stable cells is provided by the finding that TM and TC cells maintained in culture for up to 72 hr do not generate other receptors but retain the single receptor which characterizes each of these cells. Only a small percentage of cultured TG cells generate receptors for C'3 and FcM. It may therefore be concluded that the TG, TM, and TC cells are stable unireceptor-bearing cells. The TG, TM, TC, TG+C, TG+M, and TM+C lymphocytes account for approximately 50% of the circulating lymphocytes. Whether the remaining cells, the T null or TN cells, constitute the precursors for any or all of the receptor-bearing T cells remains to be determined. Unfractionated freshly isolated T cells were highly cytotoxic in the NK and PWM-mediated MICC assays but were relatively inactive in the ADCC, naturally occurring cell-mediated cytotoxicity (NOCC), and PHA- and Con-A-mediated MICC assays.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1983

[Mr 1268--a new furylmethyl-substituted benzomorphan. Comparison of its effects with pentazocine and placebo in a double-blind study].

Mr 1268 (alpha-5,9-dimethyl-2(3-methyl-3-methylfuryl)-2-hydroxy-6, 7-benzomorphan) was tested in two dosages (15 mg and 30 mg) at random on a total of 200 patients with severe postoperative pain in a double blind study against pentazocine and placebo. The analgesic effect of 30 mg Mr 1268 and 30 mg pentazocine compared with placebo was statistically significant 15 min after intramuscular injection. At the dosage applied no major respiratory or circulatory effects were observed in the patients. The minimal changes in the systolic blood pressure were of no statistical significance. Side-effects observed in many patients in the verum group were miosis and transpiration. For all other side-effects there was no statistically significant difference between placebo and the verum group or among the various verum groups.

Adult↗
PubMed1983

Surface receptors and immune activity of purified human mononuclear cells. II. The lack of correlation between rosette formation and ADCC cytotoxic activity.

The antibody-dependent cell-mediated cytotoxic (ADCC) activity of normal circulating lymphocytes is limited to those that bear receptors for the FcG of the antibody molecule. The presence of such receptors (FcGR), as detected by the ability of the cells to form rosettes with erythrocytes optimally-sensitized with rabbit IgG antibodies (EA), is not, however, the only reflection of the ADCC activity of these cells: a significant % of circulating lymphocytes can form rosettes with optimally sensitized ox EA (O-EA) indicator cells but cannot mediate ADCC lysis of O-EA. Although the FcGR-bearing lymphocytes form far fewer rosettes with chicken EA (C-EA) indicator cells, they can lyse C-EA very effectively. The O-EA are not resistant to immune lysis since they are totally lysed in the presence of complement. Similarly, circulating lymphocytes form significant numbers of rosettes with human EA but cannot lyse them. A significant % of freshly-isolated T lymphocytes form rosettes with C-EA but cannot lyse them: after incubation at 37 degrees C for 24 h, they can. Incubation T lymphocytes may exhibit a decreased capacity to form rosettes with C-EA indicating a functional loss of FcG receptors, due either to degradation or to decreased accessibility. The relation between the ability of the lymphocytes to rosette with C-EA indicator cells and their ability to lyse them is not simple or direct: this suggests that the capacity to lyse the C-EA depends on interactions other than those occurring between FcGR and the FcG of the target cell-adherent antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody-Dependent Cell Cytotoxicity↗
PubMed1983

The antibody-dependent cell-mediated cytotoxic (ADCC) reaction. III. Lymphocyte, neutrophil and monocyte cytotoxic activity as a function of the alloantibodies and erythrocyte target cells in the human allogeneic ADCC assay.

The sera of a number of individuals containing anti-A and anti-B antibodies were investigated for their ability to sensitize group AB, Rh positive erythrocytes to lysis by allogeneic circulating cells in the allogeneic ADCC assay. There was no correlation between the hemagglutination titer and the capacity to mediate ADCC lysis. Only IgG, and not IgM, alloantibodies could mediate this cytotoxic activity. A number of the alloantisera facilitated cytotoxic activity by lymphocytes whereas other alloantisera facilitated lysis by monocytes and not lymphocytes. All of the alloantisera tested sensitized the target erythrocytes to lysis by neutrophils. It is concluded that one cannot predict whether the lymphocyte or the monocyte will be the cytotoxic mononuclear cell in the human allogeneic ADCC assay since the alloantibodies, apparently directed toward the presumed identical surface structures on the identical target cells, can nevertheless preferentially impart cytotoxic activity to either of these 2 cells. The mechanism whereby the antibodies determine whether lymphocytes or monocytes will be the cytotoxic cells can only be conjectured upon at the present time.

ABO Blood-Group System↗