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Biomedical subjects

M Klinger

Publications and source records attributed to M Klinger.

At least 91 records · Page 5Linked to original sources
PubMed1992

Interactions between osteoclastic cells and biodegradable polymers in vitro.

The use of implants to stabilize fractured diaphyseal bone, to handle difficult bone damage and to perform augmentation or replacement procedures in bone has become a common method in bone surgery. In most cases metal implants were used. Biodegradability of implant materials offers new perspectives. Restoration of the physiological status in the implant site becomes possible. Allergic reaction and second operations to remove the implants can be avoided and transitional aid in wound healing by the use of biomaterials can be achieved. An in-vitro system was established to investigate the interactions between osteoclasts and biomaterials, since it is the osteoclasts which are potentially able to resorb or degrade implants. The cell's resorption capabilities as well as its morphological behavior were documented. Two biodegradable and four nonbiodegradable materials were tested. The non-degradable materials provoked specific cell behaviour patterns but were not resorbed. Fibrin tissue adhesive sealant, however, displayed resorption lacunae mediated by osteoclasts, whereas polydioxanone (PDS) showed no resorption sites but normal cellular morphology when compared to the standard control (cells on hydrophilic coated teflon dishes). Both materials appeared to be well accepted by osteoclasts. This test system was established for the valuation of biodegradable implant materials and can be used to characterize new materials concerning their resorbability and biocompatibility without superposition by other cell systems.

Aluminum Oxide↗
PubMed1992

Modified cerium-based and Gomori-based cerium methods for light microscopic phosphatase histochemistry: the cerium-perhydroxide-diaminobenzidine-nickel (Ce-H2O2-DAB-Ni and Ce/Ce-H2O2-DAB-Ni) two-step procedures.

Some modified cerium-based and Gomori-based cerium methods for the demonstration of phosphatase activity in cryostat sections were described. Dextrane as stabilizing agent was added to the incubation media for ATPase, 5'-Nase, and TPPase. The oxidation of the CeIII-phosphate primary reaction product in a separate step by H2O2 before the DAB incubation yielded an increase of the intensity of the DAB-based visualization reaction (Ce-H2O2-DAB-Ni two step method). The sensitivity of the histochemical enzyme reaction was remarkably increased if CeIII-ions were employed as amplifying agent (Ce/Ce-H2O2-DAB-Ni two-step method). A new suitable DAB medium consisting of 0.015% DAB, 2.0% Ni-sulphate, 15% methanol, and 0.005% H2O2 in 0.1 mol/l acetate buffer, pH = 5.2, was used. The disadvantage of diffuse background staining has been overcome by addition of 15% methanol to the DAB solution. Electrovalently bound CeIII (cerophilia) was removed by treatment of the incubated sections with CeIII-citrate (CeIII-complexation). In addition, a novel membrane floating incubation for sections is proposed. At present, the modified procedures are some of the most sensitive modes for the demonstration of phosphatases and improve the earlier described cerium-DAB one-step technique (Halbhuber et al. 1988b).

Animals↗
PubMed1991

Improved light microscopic demonstration of D-amino acid oxidase activity in cryotome sections using cerium ions as capturing and amplifying agent--the Ce/Ce-H2O2-DAB procedure.

The light microscopical demonstration of D-amino acid oxidase (AAOX) activity with cerium (Ce III) as the capturing agent was improved. The incubation medium was stabilized by the employment of triethanolamine and detrane complexed cerium. A considerable increase in intensity of the reaction was accomplished by treatment of the AAOX-incubated sections with Ce III which reacted with the primary reaction product Ce IV-perhydroxide to form Ce IV-hydroxide. In this way the primary reaction product was reduced and enlarged concomitantly. The Ce IV-hydroxide was converted into Ce IV-perhydroxide by H2O2, which was visualized by blue-black stained Ni-DAB complexes. Thus, Ce III is used as capturing agent as well as amplifier (Ce/Ce-H2O2-DAB method). The primary reaction product Ce III-phosphate formed by coreacting phosphatases was selectively extracted by citrate containing glycine-NaOH buffer while Ce IV-perhydroxide remained in the sections. In model experiments it was proven that the perhydroxide groups in the Ce IV-perhydroxide compound initiate predominantly the DAB polymerization while the contribution of Ce III and Ce IV is small.

3,3'-Diaminobenzidine↗
PubMed1991

[Activity of erythrocyte complement receptors class 1 in various kidney diseases].

UNLABELLED: The activity of the erythrocyte complement receptors type 1 (CR1) was measured in four groups: a control group--42 healthy persons, 18 patients with lupus nephritis (morphologic types: membranous, membranoproliferative, and proliferative), 16 patients with primary idiopathic membranous glomerulonephritis (GN), 20 patients with primary idiopathic membranoproliferative GN, and 23 chronic haemodialysis patients, in 20 of them the cause of the end-stage renal failure was primary idiopathic GN. The erythrocyte CR1 activity was determined by the immune adherence test. In the groups of the lupus nephritis and of the end-stage renal failure was observed a significant drop in erythrocyte CR1 activity. On the contrary the patients with primary idiopathic membranous and membranoproliferative GN exhibited a significantly greater erythrocyte CR1 activity than the normals. CONCLUSIONS: 1. The genetic predisposition to primary idiopathic GN is not reflected on the level of the erythrocyte CR1 system, what is distinct from the situation occurred in lupus nephritis, despite similarities in their immunopathogenesis. 2. The development of the end-stage renal failure in the course of primary idiopathic GN shows a inhibitory effect on erythrocyte CR1 activity.

Adolescent↗
PubMed1990

Radiolocalization of human prostate tumor in a mouse subrenal capsule model by monoclonal antibody TURP-27.

The subrenal capsule assay was used to determine if 125I-labeled anti-prostate monoclonal antibody TURP-27 could target human prostate tumor fragments implanted under the renal capsule of normal immunocompetent C57 BL/6 mice. Maximal binding and optimal tumor to non-tumor tissue ratios occurred within 24-48 hours postadministration of 125I-TURP-27. No significant localization was observed in mice bearing TURP-27 antigen-negative human colon tumor tissue implants or with an isotype-matched control monoclonal antibody. These preclinical data suggest that TURP-27 may have clinical application for imaging metastatic prostate tumors and further application in immunoconjugate and/or radiotherapy of prostate cancer.

Animals↗
PubMed1990

Resorption of fibrin tissue adhesive sealant by isolated osteoclasts in culture.

The tissue tolerance of fibrin tissue adhesive sealants has been investigated. These materials are increasingly being used to close wounds and to stabilize spongy bone transplants. An in vitro model consisting of isolated osteoclasts in primary cell culture was used. The 2 commercially available tissue adhesive sealant protein solutions differ substantially with regard to the spreading and resorption capacity of the cultivated osteoclasts.

Animals↗
PubMed1990

Effect of parathyroid hormone on human T cell activation.

Lymphocytes have receptors for PTH and patients with chronic renal failure have high blood levels of PTH and impaired lymphocyte function. It is possible, therefore, that PTH affects lymphocyte function. We studied the interaction between PTH and proliferation of human lymphocytes in vitro and examined potential mechanisms for such an interaction. 1-84 PTH stimulated in a dose dependent manner PHA-induced proliferation of T cells but had no effect on PWM-induced proliferation. The hormone did not alter CD4/CD8 ratio. Inactivation of PTH abolished its stimulatory effect. PTH augmented IL-2 production by PHA-activated T cells but did not increase expression of IL-2R. 1-34 PTH also stimulated PHA-induced T cell proliferation. TPA augmented PHA-induced T cell proliferation but the addition of PTH to the culture stimulated by PHA and TPA did not augment further the proliferation of T cells. Staurosporin reversed the stimulation by PTH of the PHA-induced lymphocyte proliferation. Both 1-34 and 1-84 PTH stimulated cyclic AMP production by lymphocytes. Forskolin did not affect PHA-induced T cell proliferation although it stimulated cyclic AMP generation. The results show that: 1) PTH acts on T cells; 2) acute exposure to PTH augments PHA-induced T cell proliferation and IL-2 production; 3) this action of PTH is related to its biological activity and is most likely due to the ability of PTH to enhance entry of calcium into cells and/or stimulation of protein kinase C but is independent of cyclic AMP generation.

Adult↗
PubMed1990

Evidence of impaired T cell function in hemodialysis patients: potential role for secondary hyperparathyroidism.

Previous studies in our laboratory showed that the T cell is a target for parathyroid hormone (PTH) action. It is theoretically possible, therefore, that chronic exposure of the T cells to high blood levels of PTH in patients with chronic renal failure may adversely affect T cell function. We examined in both normal subjects and dialysis patients several aspects of T cell function, including (1) T cell proliferation in response to phytohemagglutinin (PHA) mitogen with and without PTH and with and without exogenous interleukin 2 (IL-2); (2) the IL-2 production induced by PHA with and without PTH, and (3) resting levels of cytosolic calcium--[Ca2+]i--and the increment in [Ca2+]i in response to anti-CD3 antibody. Although PHA significantly (p less than 0.01) stimulated proliferation of T cells from both normal subjects and dialysis patients, the magnitude of the stimulation was significantly (p less than 0.01) smaller in the latter group. In both normal subjects and dialysis patients, exogenous IL-2 alone stimulated T cell proliferation, and the magnitude of the stimulation was similar to that produced by PHA. Also, IL-2 augmented PHA-induced proliferation of T cells from normal subjects, but failed to do so in T cells from dialysis patients. PHA did not augment IL-2 production by T cells from dialysis patients, and PTH did not correct this defect. The resting levels of [Ca2+]i in T cells from dialysis patients were significantly (p less than 0.01) higher, and the increments in [Ca2+]i in response to anti-CD3 antibody were significantly (p less than 0.01) lower than in T cells from normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Parathyroid hormone inhibits B cell proliferation: implications in chronic renal failure.

B cell proliferation is impaired in patients with chronic renal failure, but the mechanisms underlying this defect are not known. Lymphocytes have receptors for parathyroid hormone, and it is possible that the state of secondary hyperparathyroidism of renal failure is responsible for the B cell defect. Our studies were designed to (a) examine T cell-independent B cell proliferation [3H)thymidine incorporation) induced by Staphylococcus aureus Cowan 1 after 5 days of culture, (b) evaluate the effect of parathyroid hormone on S. aureus Cowan I-induced B cell proliferation, and (c) investigate the mechanisms through which parathyroid hormone may exert its effect on B cell proliferation. Lymphocytes were obtained from 37 normal subjects and 21 dialysis patients. S. aureus Cowan I induced significant stimulation (P less than 0.01) of the proliferation of B cells from both groups, but the effect was smaller on B cells from dialysis patients (10.0 x 10(3) +/- 1.4 x 10(3) cpm) than on those from normal subjects (21.8 x 10(3) +/- 2.0 x 10(3) cpm). Both the intact molecule of parathyroid hormone (1-84 PTH) and its amino-terminal fragment (1-34 PTH) caused significant inhibition of proliferation of B cells from normal subjects in a dose-dependent manner, with the effect being significantly greater (P less than 0.01) with an equimolar concentration of 1-84 PTH than that of 1-34 PTH. Inactivation of 1-84 PTH by oxidation abolished most of its inhibitory effect on B cell proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The use of butorphanol tartrate for the prevention of canine intussusception following renal transplantation.

Butorphanol tartrate (0.05 mg/kg, im) was included in the preanesthetic medication in 15 out of 29 conditioned female mongrel dogs (22.7-27.3 kg body wt) undergoing renal autotransplants as part of a 48-h kidney preservation study. Four postoperative intussusceptions were noted (3 jejunojejunal, 1 ileocolic) among the 14 dogs without butorphanol, whereas no intussusceptions developed in the 15 dogs receiving butorphanol as part of the preanesthetic protocol. In a prior study, 2 out of 18 dogs undergoing renal autotransplants without the use of butorphanol as part of a 24-h kidney preservation study developed intussusceptions (jejunojejunal). With the exception of butorphanol the anesthetic protocol was the same for all 47 dogs receiving transplants. Throughout these studies the surgical team remained constant, and all dogs were negative for parasites and systemic infectious disease pre- and postoperatively. The results indicate that the use of butorphanol tartrate as part of a preanesthetic protocol is effective in preventing canine intestinal intussusception following renal autotransplantation.

Animals↗
PubMed1990

[Retinoblastoma].

Basic elements of retinoblastoma were evaluated in a sample of 14 patients. The analysis of the sex distribution has revealed that a greater number of male children was affected by the disease (p = 0.64). The average age ranged from 2 months to 3.5 years. Usually the first visible symptom is a white pupillary reflex, while the first clinical findings show that there is a tumorous formation in the fundus. A significant correlation between the age of the patient and the length of his survival was found by Fisher's test, as well as between the laboratory findings of tumor cells in the optical nerve incision and the length of survival.

Child, Preschool↗