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T Block

Publications and source records attributed to T Block.

33 records · Page 2Linked to original sources
PubMed1988

Application of a fibrinogen-thrombin-collagen-based hemostyptic agent in experimental injuries of liver and spleen.

FTCH is a recently developed material which consists of a collagen fleece containing fibrinogen, thrombin, and aprotinin integrated into its surface. FTCH is highly effective in sealing of tissues and in establishing hemostasis. We evaluated FTCH in experimentally produced liver (n = 6) and splenic (n = 12) injuries in 18 adult mongrel dogs. The stability of the parenchymal seal of the splenic injuries was tested by splenic tissue pressure elevation after temporary ligation of the splenic vein. No breakthrough bleeding occurred up to a parenchymal pressure of 16.3 +/- 5 mm Hg. Complete hemostasis was easily achieved in all animals before closure. When the dogs were re-explored postoperatively at intervals of either 14 or 30 days, there was no gross evidence of recurrent bleeding. Histologic examinations demonstrated a partially regenerated capsule covering an unspecific fibrovascular granulation tissue and progressive resorption of FTCH without significant inflammatory response. We conclude the following: FTCH provides adequate hemostatic control of experimental liver and splenic injuries. FTCH has excellent tissue compatibility and can be applied easily and safely to hemorrhaging parenchymal wounds. It will not replace adequate surgical techniques, but could be useful as a quickly available and easily applicable hemostatic means in diffuse or acute bleeding of liver and spleen.

Animals↗
PubMed1988

[Metaraminol in therapy of various forms of priapism].

A total of 19 patients (aged 17-66 years) with priapism received primarily conservative treatment in the form of aspiration of blood from the cavernous bodies and subsequent intracavernous (i.c.) administration of the alpha-adrenergic drug metaraminol. In 15 patients the priapism was due to i.c. injection of vasoactive agents; 1 patient each it had developed after hemodialysis, during oral prazosin medication, and in conjunction with Fabry's disease; and in 1 patient the etiopathogenesis was unknown. Treatment of priapism with metaraminol was successful in the first 15 patients and in 2 patients with priapism due to hemodialysis and oral prazosin medication. Therapy failed in long-lasting priapism associated with Fabry's disease and in priapism of unknown etiopathogenesis. Penile detumescence took place in the first 15 patients 3 min to 2.5 h after the injection of 2-4 mg metaraminol. Hemodialysis- and prazosin-linked priapism was treated with 5 and 2 mg metaraminol, respectively; in these patients erection subsided within 15 and 4 min after onset of therapy. In a further 2 patients in whom therapy had failed Al-Ghorab shunts were constructed, with the subsequent postoperative complication of erectile impotence. Injection of metaraminol must be carried out under strict supervision of the patient's circulatory system: doses of 4 mg metaraminol or more led to an increase in blood pressure and heart rate. In 15 patients with priapism induced by i.c. application of vasoactive agents, the analysis of blood gas parameters demonstrated a severe hypercapnia (70.3 +/- 10.0 mm Hg) and acidosis (pH 7.08 +/- 0.08) 5-10 h after the onset of erection, but severe hypoxia (37.0 +/- 16.6 mm Hg) was not found until erection had lasted for more than 10 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

The effectiveness of a fibrinogen-thrombin-collagen-based hemostatic agent in an experimental arterial bleeding model.

The hemostyptic agent used in this study is a recently developed material that consists of a collagen fleece containing fibrinogen, thrombin, and aprotinin integrated into its surface (FTCH) with excellent topical hemostyptic properties. The potential use of this substance for cardiovascular surgery was evaluated in a canine arterial bleeding model, which allowed comparison of the new agent with previously used pure collagen (CHF) as well as study of the hemostyptic under elevated blood pressure conditions. The results revealed that FTCH induced reliable hemostasis in 10-mm injuries of the canine hypogastric artery up to a systolic blood pressure of 260 mmHg, whereas bleeding control by CHF alone was impossible. To assess the long-term reliability of FTCH, the dogs were re-explored at intervals of 14 and 31 days after operation. At relaparotomy, the arteries were patent and there was no evidence of recurrent bleeding, thrombosis formation, or aneurysmatic changes. Histologic examinations showed well-healed vascular lesions covered by cell-depleted collagen tissue and a partially resorped hemostyptic. FTCH will not replace adequate surgical techniques but could be useful as a quickly available and easily applicable hemostatic means in otherwise uncontrollable diffuse or acute bleeding in cardiovascular surgery.

Animals↗
PubMed1987

[Value of nuclear magnetic resonance tomography in the staging of tumors of the urinary bladder].

The accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) in the staging of bladder tumors was evaluated in 46 patients. In the T-staging MRI was superior to CT. With MRI 38 out of the 46 tumors were correctly staged into the four groups T0, T1-T3a, T3b and T4. With CT this classification was only possible in 28 cases. The main advantages of MRI were the capability for multiplanar imaging, which improved evaluation of the bladder base and the bladder dome, as well as a better differentiation between tumor recurrency and fibrosis. In the evaluation of adenopathy MRI and CT proved to be equal and demonstrated a sensitivity of 50%.

Carcinoma, Transitional Cell↗
PubMed1986

Use of iohexol in the radiographic diagnosis of ischemic bowel.

This study evaluates the use of iohexol as a radiographic diagnostic contrast agent in normal animals and those with experimental bowel ischemia and obstruction. Eighteen rats and 12 rabbits were gavaged with iohexol in a dose of 7.5 mL/kg using concentrations of 140 mg I/mL (isotonic with blood) or 300 mg I/mL. In addition, four rabbits had intraperitoneal iohexol injection and three were given gastrografin gavage. Experimental groups included normal bowel controls, bowel injury induced by ischemia and alcohol contact, bowel obstruction by ligature, and intraperitoneal injection. Serial abdominal radiographs and plasma concentrations of iohexol were obtained. Iohexol remained stable throughout the gastrointestinal tract, retained its intensity, and was well visualized up to four days after administration. Bowel images were fair at concentrations of 140 mg I/mL and excellent at 300 mg I/mL. Gastrografin caused bowel distention and poor visualization related to dilution. It also precipitated in the stomach. Iohexol was rapidly absorbed from the peritoneal cavity and excreted by the kidneys, without causing peritonitis. Rat plasma iohexol levels were three times controls in obstructed bowel and 80 times controls if there was mucosal injury without perforation. Rabbit peak plasma levels were 30 times greater following intraperitoneal injection than with gastric gavage. These observations suggest that iohexol may be useful as a gastrointestinal contrast agent. Measuring plasma iohexol levels may be helpful in the evaluation of suspected bowel ischemia or perforation in the clinical setting.

Animals↗
PubMed1985

Genetic linkage but independent expression of functional HSV-1 tk and mammalian aprt genes after cotransfer to L cells.

DNA-mediated gene transformation of mouse Ltk-aprt-hprt-cells was used to obtain stable, doubly selected transformants simultaneously expressing herpes virus thymidine kinase (TK) and mammalian adenine phosphoribosyltransferase (APRT). Cotransformants occurred at a frequency of 5 X 10(-6), a similar frequency for the transfer of the aprt marker has been previously observed. Isozyme and Southern blot analysis show that the TK and APRT expressed in these transformants resulted from gene transfer. For one stable cotransformant, [3H]thymidine [( 3H]TdR) selection against TK activity resulted in the loss of APRT activity as well, suggesting that these genes had become genetically linked together. Similarly selection against APRT expression resulted in the loss of a subset of the transferred herpes simplex virus tk genes. 5-Bromodeoxyuridine (BUdR) selected TK- variants differed from [3H]TdR selected TK- variants, in that they retained tk genes. However, BUdR-selected variants expressed full levels of APRT. Therefore, even though the transferred tk and aprt genes had become genetically linked together, they were, in this case, independently expressed since these cells were phenotypically TK- and APRT+.

Adenine Phosphoribosyltransferase↗
PubMed1984

Mutants of PC12 cells with altered cyclic AMP responses.

PC12 cells, derived from a rat pheochromocytoma, were mutagenized and selected in media containing agents known to elevate intracellular concentrations of cyclic AMP (cAMP). More than 40 clones were isolated by selection with cholera toxin or 2-chloroadenosine or both. The variants that were deficient in accumulating cAMP were obtained by using a protocol in which 1 microM 8-bromo-cAMP was included in addition to the agonist. Certain of these variants were partially characterized with respect to the site of altered cAMP metabolism. The profiles of adenylate cyclase activity responsiveness of certain variants to guanosine-5'-(beta, gamma-imido) triphosphate and to forskolin resembled those of UNC and cyc phenotypes of S49 lymphoma cells, which are functionally deficient in the GTP-sensitive coupling protein, Ns. Other variants were characterized by increased cyclic nucleotide phosphodiesterase activity at low substrate concentration. Diverse morphological traits were observed among the variants, but it was not possible to assign them to a particular cAMP phenotype. Two revertants of a PC12 mutant were isolated and observed to have regained a cellular cAMP response to 2-chloroadenosine and to forskolin. It is hoped that these PC12 mutants will have utility for defining cAMP-mediated functions, including any links to the action of nerve growth factor, in cells derived from the neural crest.

2-Chloroadenosine↗
PubMed1984

Analysis of in situ inflammation of allogeneic canine kidney grafts under antilymphocyte globulin treatment.

15 mongrel dogs receiving allografts were treated with antilymphocyte globulin (ALG; 20 mg/kg b.w. daily). The kinetics and distribution of inflammatory cells invading the transplant were analyzed by transplant aspiration cytology. Only transplant aspiration cytology enables one to observe the direct influence of ALG within the grafts themselves. Although a low-potency ALG was used, ALG-treated animals showed a significant long-term suppression of the in situ inflammation of lymphocytes (p less than 0.05) and lymphoblasts (p less than 0.05) during the entire experimental period. Other leucocyte populations were influenced to a lesser degree. This in situ reduction combined with a significant prolongation of graft function (p less than 0.001) establishes the beneficial effect of ALG in suppressing cell-mediated immune responses in renal allografts.

Animals↗
PubMed1983

Use of iron- or selenium-coupled monoclonal antibodies to cell-surface antigens as a positive selection system for cells.

A system which confers selective growth advantage to cells expressing particular surface proteins would be extremely desirable, for such a technique would allow the study of receptors using somatic cell genetic techniques such as DNA-mediated cell transformation and selection of over-producing cell variants. Polypeptides bound to surface receptor, and antibodies bound to surface antigens generally are taken up efficiently by cells by endocytotic mechanisms. Several investigators have accordingly developed useful techniques for selection against cells expressing surface receptors and antigens, using hormones and antibodies conjugated to toxins. We reasoned that conjugation of nutrients to antibodies or hormones conversely might permit a positive selective pressure to be applied in appropriately constituted medium. We report here that monoclonal antibodies to cell-surface antigens will indeed deliver nutritional iron and selenium to cultured cells in an antigen-specific manner.

Animals↗
PubMed1983

Behavioral treatment methods for alcoholism.

This chapter offers a review of the behavioral methodology directed to the treatment of alcoholism. Beginning with an outline of the theoretical bases of behavior therapy and assessment, a review with some historical perspective is undertaken of the chemical, electrical, and covert aversion treatments of alcoholism. Thereafter, the procedures of the social skills-training strategies (including marital skills and assertiveness training) are presented, followed by a discussion of the relaxation and desensitization techniques. The operant methodologies are illustrated by contingency contracting and the community-reinforcement approaches. Within the broad-spectrum procedures, a description of self-control training and an example of a broad-spectrum treatment study are offered. It is noted that although the merits of these various techniques are becoming widely recognized in the alcoholism treatment literature, the behavior therapeutic approaches to alcoholism have yet to receive widespread public acceptance. It is anticipated that future studies of treatment effectiveness will contribute to an increasing appreciation of the advantages of behavioral therapies to the management of alcohol abuse and dependence.

Alcoholism↗
PubMed1983

The nerve growth factor receptor on PC12 cells: interconversion between two forms with different binding properties.

PC12 cells possess two classes of nerve growth factor (NGF) receptors on their surfaces which can be distinguished by kinetic criteria. The majority class binds and releases 125I-NGF at a relatively rapid rate and has been called fast. The second class of receptors has been called slow because of relatively slower rates of binding and release of 125I-NGF, and also may be distinguished from fast receptors by their cytoskeletal association and resistance to trypsin. PC12 cell plasma membranes were prepared and shown to have only the fast class of receptors. These membranes were fused to receptorless 3T3 cells with polyethylene glycol. The resultant fused cells were shown to possess NGF receptors, essentially all of which behave like slow receptors. Immunofluorescence microscopy was used to monitor the introduction of PC12 cell membrane and NGF receptors into 3T3 cells. Results obtained with C10-2, a monoclonal antibody specific for a major PC12 cell-surface antigen. show that up to 90% of 3T3 cells receive PC12 membrane and that the PC12 membrane becomes integrally incorporated into the 3T3 cell plasma membrane. It is suggested that an association of receptors with cytoskeleton may be involved in the conversion of fast to slow receptor behavior, and that the differing proportion of fast and slow NGF receptors in PC12 and 3T3 cells reflects the differing cytoskeletal organization of these cells.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

A phage-linked immunoabsorbant system for the detection of pathologically relevant antigens.

This report describes a novel system for the immunological detection of immobilized antigen. The detection of herpes simplex virus (HSV) antigen was used as an example. Bacteriophage M13, containing the E. coli lac Z gene, was used as the "reporter" molecule in an immunoassay which is otherwise analogous to the enzyme-linked immunoabsorbant assay (ELISA). Briefly, HSV infected cells were incubated with a mouse monoclonal antibody specific for HSV antigen, followed by rabbit anti-mouse serum and mouse anti-M13 serum. Immune complexes were incubated with viable M13 phage. M13 binding was due to the presence of M13 antibodies, whose presence ultimately depended on the binding of monoclonal antibody to HSV. Phage was recovered by elution in pH = 11. Recovered phage was used to infect E. coli. M13 was quantitated by either plaque assay or by an assay for phage-induced beta-galactosidase activity in appropriate E. coli strains. The amount of M13 recovered was proportional to the number of HSV infected cells probed. Therefore, M13 served as a "bio-amplifiable tag" to antibody, as enzymes do in the ELISA. Since M13 is viable, its signal can be amplified by infection of susceptible bacteria, and the promise for an enormously sensitive immunoassay exists. The sensitivity of the assay described here is compared to the ELISA in the detection of HSV infection cells, as an example of the novel assay's potential. Significantly, the novel assay was more sensitive than the ELISA when samples were tested under identical circumstances. This technique is called the phage-linked immunoabsorbant assay (PHALISA), by analogy to the ELISA.

Antigens, Viral↗