Clotting times and antithrombin III activity in cats with naturally developing diseases: 85 cases (1984-1994)

OBJECTIVE: To determine the prevalence of abnormalities of in vitro prothrombin time (PT) and activated partial thromboplastin time (APTT), or antithrombin III (ATIII) activity or all 3 variables in cats; and the association of abnormalities of these variables with naturally developing diseases or disorders. DESIGN: Retrospective study. ANIMALS: 85 cats from which blood had been obtained for measurement of a coagulation profile (PT, APTT, and ATIII activity) and concentration of fibrin degradation products. PROCEDURE: Medical records from the Texas A&M College of Veterinary Medicine were reviewed to determine clinical diagnosis, results of CBC and coagulation profile, and clinical evidence of abnormal bleeding or thrombotic disease. RESULTS: 38 cats had one or more abnormality in the coagulation profile; most had multiple abnormalities. Twenty of these 38 cats had concurrent thrombocytopenia. Thrombocytopenia was identified in 9 of 47 cats in which results of the coagulation profile were normal. Most cats did not have clinical evidence of a coagulation disorder, and testing had been requested as part of a diagnostic work-up or before surgery. Diseases commonly associated with laboratory evidence of a coagulation disorder, either singly or in combination, included hepatic disease, neoplasia, and systemic infections. CLINICAL IMPLICATIONS: On the basis of laboratory evidence, hemostatic disorders develop more commonly in cats than clinical signs would suggest. Coagulation profiles may be warranted in high-risk cats to alert clinicians to potential problems.     

Pathogenicity of human anti-platelet factor 4 (PF4)/heparin in vivo: generation of mouse anti-PF4/heparin and induction of thrombocytopenia by heparin

Acinetobacter baumannii strain A148, a clinical isolate resistant to imipenem (MIC = 32 mg l-1), synthesized two beta-lactamases with pIs 6.3 and > 9.2. The pI 6.3 enzyme hydrolyzed the penicillins, including isoxazoylpenicillins, first-, second- and, to a lesser extent, third-generation cephalosporins. It was inhibited by chloride ions and by the penem beta-lactamase inhibitor BRL 42715. Clavulanate was a weak inhibitor and EDTA did not affect the beta-lactamase activity. This enzyme also hydrolyzed imipenem with a catalytic efficiency (Kcat/Km) of 1500 mM-1 s-1. Moreover, this purified beta-lactamase produced a positive microbiological clover-leaf test with imipenem. Therefore, the pI 6.3 beta-lactamase was considered to be involved in the imipenem resistance of A. baumannii strain A148.     

Thermodynamic Assessment of DyCl3-MCl （M= Na, K, Rb, Cs） Systems

Using the CALPHAD （Calculation of Phase Diagram） technique, the DyCl3-MCl （M = Na, K, Rb, Cs） systems were optimized and calculated. The modified quasi-chemical model in the pair approximation for short-range ordering was used to describe the Gibbs energies of the liquid phase in these systems. From the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized base on an interactive computer-assisted analysis. The optimized parameters and the experimental data were thermodynamically self-consistent. The optimized results were discussed.     

Interaction of heparin with canine coagulation proteins: in vivo and in vitro studies

The effects of heparin on the coagulation profile and on specific factor activity in canine plasma have been examined both in vivo and in vitro. The results show that the prolongation of the partial thromboplastin time of plasma produced by heparin is, at least in part, the result of the interaction of heparin with the intrinsic Factors VIII, IX and XI and the inhibition of their procoagulant activity by heparin. A significant correlation was found between the partial thromboplastin time assay and the circulating heparin activity following intravenous administration of heparin to dogs. The results confirm the suitability of the partial thromboplastin time assay for monitoring heparin therapy in the dog.     

Human platelet Ca2+ mobilization, glycoprotein IIb/IIIa activation, and experimental coronary thrombosis in vivo in dogs are all inhibited by the inotropic agent amrinone

BACKGROUND: Inotropic drugs are often used to treat acute, severe heart failure resulting from acute myocardial infarction and other unstable coronary artery syndromes. However, catecholamine inotropic agents may potentiate coronary thrombosis via a platelet alpha2-adrenergic mechanism, thus exacerbating the original problem. The present studies were designed to determine whether the nonadrenergic inotropic and vasodilator drug amrinone, which elevates platelet cAMP levels, would both inhibit human platelet Ca2+ mobilization and adhesion molecule expression ex vivo and protect against experimental coronary thrombosis in vivo in dogs. METHODS AND RESULTS: Human platelets in suspension were preincubated with amrinone 2.5 to 15 microg/mL; stimulated with the agonists thrombin 0.1 U/mL, ADP 10(-6) mol/L, or arginine vasopressin 10(7) mol/L; and studied for Ca2+ mobilization, glycoprotein IIb/IIIa activation, and P-selectin expression by fluorescent flow cytometry methods. Experimental coronary thrombosis in vivo was studied in an open-chest dog model with critical coronary artery stenosis and deep vessel wall injury. Results showed that at the cellular level, amrinone inhibited agonist-induced Ca2+ mobilization and had modest inhibitory effects on adhesion molecule expression. In vivo in dogs, intravenous amrinone 2 mg/kg plus infusion at 20 microg x kg(1) x min(-1) completely abolished coronary thrombosis. CONCLUSIONS: The fact that amrinone inhibited human platelet activation at the cellular level and protected against experimental coronary thrombosis in vivo in dogs suggests a potentially advantageous antithrombotic action for this inotropic and vasodilator drug.     

Migration and activation of antigen-specific CD8+ T cells upon in vivo stimulation with allogeneic tumor

The response of CD8+ T cells to allogeneic tumor was studied by adoptive transfer of cells from TCR transgenic 2C mice specific for Ld alloantigen. Transferred cells were monitored during the course of a response to i.p. challenge with live P815 (H-2d) using the 1B2 mAb specific for the 2C TCR. Tumor was present in the draining LN and spleen within 3 to 4 days of challenge. The first changes in 1B2+ cells occurred in the spleen on day 4; VLA-4 expression increased in an Ag-specific manner and L-selectin expression decreased in an Ag-nonspecific manner. The number of 1B2+ cells in the spleen declined over days 4 to 6. The first detectable increase in CD25 expression and blast transformation was in the peritoneal cavity beginning days 5 and 6. Clonal expansion was largely limited to this site and was maximal on day 8. As expansion occurred in the peritoneal cavity; the number of 1B2+ cells in the draining LN and spleen also increased. These cells had an activated phenotype (CD44(high), VLA-4(high)) but most did not express CD25 and were not blasts. These results suggest that initial Ag recognition in the spleen results in altered expression of adhesion receptors so that cells gain access to the peritoneal cavity where they undergo clonal expansion and differentiation. Following the response, 1B2+ cells decline in number but a memory population (CD44(high), L-selectin(high and low)) persists for long times in the spleen and LN.     

Differential activation of T cells by natural antigen peptide analogues: influence on autoimmune and alloimmune in vivo T cell responses

Recent studies using synthetic altered peptide ligands (Analogues) have led to the fine dissection of TCR-mediated T cell functions elicited by Ag recognition. Certain Analogues behave as full agonists of the antigenic peptide while others are partial agonists in that they only trigger selected T cell functions. Additionally, peptide Analogues can behave as antagonists by inhibiting functions of T cell clones when coincubated with the wild-type peptide. In fetal thymic organ cultures, synthetic altered peptide ligands can impact T cell repertoire selection. However, the influence of naturally occurring peptide Analogues on T cell immunity in vivo remains hypothetical. We previously reported that, in B10.A mice, immunogenicity and tolerogenicity of the self-MHC class I peptide, Ld 61-80, were influenced by the presentation of a cross-reactive self-peptide, Kk 61-80. Here, we show that Kk 61-80 self-peptide represents a partial agonist of Ld 61-80 in that it induced the proliferation but not the lymphokine production of Ld 61-80-primed T cells. Next, we showed that presentation of Kk 61-80 Analogue peptide mediated T cell tolerance toward Ld 61-80 self-peptide. Alternatively, when Ld protein represented an alloantigen displayed on transplanted cells, immunization with Kk 61-80 Analogue sensitized recipient mice to Ld 61-80 peptide, thus inducing potent immune responses to donor cells. These results show that the presentation of natural Analogue peptides may represent an essential component of T cell responses involved in autoimmunity and transplant rejection.     

A new in vitro model for studying human T cell differentiation: T(H1)/T(H2) induction following activation by superantigens

A new T(H1)/T(H2) in vitro model for mechanistic studies and drug screening in human T cells was established working with ficoll-separated PBMCs or elutriated lymphocytes cultured in serum-free medium. Human T cells could be kept viable and reactive in this medium for several months. In this model, superantigens (SAs) were used to activate exclusively those T cell clones which were known to express specifically SA-binding Vbeta-chains of the T cell receptor. It was possible to identify the activated SA-specific T cells among the whole T cell population by using monoclonal antibodies against these Vbeta-chains and to follow responses involving receptor regulation and cytokine expression. The flow cytometric analysis revealed, that SA exposure caused an upregulation of the IL-2 receptor selectively in the SA-specific subpopulation. Only the T cells of this subpopulation could be shifted towards T(H1) or T(H2) differentiation, which was determined by the distribution of IFN-gamma and IL-4 positive cells. Regulation of IFN-gamma could be detected by flow cytometry after 18 h and that of IL-4 on the third day of cell culture. The differentiation status could be influenced by various measures: T(H1) shifts were achieved in the presence of IL-12 and anti-IL-4, whereas, T(H2) shifts were induced more slowly with monocyte-reduced elutriated lymphocytes in the presence of IL-4, IL-6, anti-IL-12, 1alpha,25-dihydroxy-vitamin-D3 or combinations thereof. It was found that sialidase stimulated whereas TGF-beta and pentoxifylline suppressed both kinds of T cell response. The T(H1)/T(H2) differentiation persisted for several weeks after primary activation if cells were expanded in IL-2 containing serum-free culture medium. Therefore, this human T(H1)/T(H2) in vitro model should be ideal for studying early and late events of infection, allergy, and autoimmunity as well as for investigating the cellular interactions involved. In addition, the early detection of the response pattern makes this model potentially useful for drug screening.     

Cytokeratin tumor markers in ovarian carcinoma: tissue polypeptide specific antigen (TPS) and M3/M21

The aim of the present study was to evaluate the clinical usefulness of the cytokeratin tumor marker M3/M21 as a screening, prognostic, and monitoring marker for ovarian cancer and as a predictive marker in patients with adnexal masses. In order to determine the specificity of the M3/M21 test we investigated M3/M21 serum levels in several benign conditions. The cytokeratin tumor markers M3/M21 and Tissue Polypeptide Specific Antigen (TPS) were also investigated in the follow-up of ovarian cancer patients. We evaluated M3/M21 serum levels in 75 patients suffering from ovarian cancer FIGO stages Ia to III, using a prototype immunoradiometric assay (IRMA). Sera of patients with benign cysts, endometriosis, pelvic inflammatory disease, inflammatory bowel disease and liver cirrhosis were evaluated in 90, 10, 38, 10, and 20 cases, respectively. Furthermore, we analyzed TPS serum levels by means of IRMA during the follow-up of 40 patients suffering from ovarian cancer. With a sensitivity of 57% and a specificity of 95% M3/M21 was not suitable as a screening marker for ovarian cancer. Although M3/M21 was able to discriminate between ovarian cancer and benign adnexal tumors (univariate logistic regression, p = 0.0003), M3/M21 did not provide additional information (in addition to CA 125) (multivariate logistic regression, p = 0.2). M3/M21 serum levels were elevated in several benign conditions such as liver cirrhosis and inflammatory bowel disease. In ovarian cancer patients elevated M3/M21 serum levels prior to therapy were associated with a poor overall and disease-free survival (log-rank test, p = 0.03, and log-rank test, p = 0.01, respectively). In patients with recurrent ovarian cancer M3/M21 and TPS showed median lead-time effects of 3.2 and 3.9 months, respectively. M3/M21, while obviously not suitable for screening or differential diagnosis of adnexal masses, could be useful as an additional prognostic factor. M3/M21 and TPS are valuable tumor markers in the follow-up of ovarian cancer patients.     

Thermodynamic optimization and calculation of phase diagrams of YbCl3-MCl (M=Na, K, Rb, Cs)

YbCl3-MCl (M = Na, K, Rb, Cs) systems were optimized and calculated using the CALPHAD (CALculation of PHAse Diagram) technique. The modified quasi-chemical model in the pair-approximation for short-range ordering was used to describe the Gibbs energies of liquid phase in the systems. On the basis of the measured phase diagram data and experimental thermodynamic properties, a series of thermodynamic functions were optimized and calculated through an interactive computer-assisted analysis. Furthermore, some reasonable discussions on the thermodynamic parameters for these strong interaction binary systems were carried out. The results showed that the optimized parameters and experimental data are thermodynamically self-consistent.     

Predation, aggression, and activation levels in food-deprived sunfish (Lepomis macrochirus and L. gibbosus): Motivational interactions.

Three experiments investigated the effects of food deprivation on several behavioral categories in a total of 56 bluegill and pumpkinseed sunfish ( Lepomis macrochirus and L. gibbosus, respectively). In Exp I, predatory behavior and general activity were observed under 5 levels of deprivation. For both species, predation measures increased in a similar negatively accelerating manner with increasing deprivation, while activity changed in a more complex fashion. Exp II examined the effects of deprivation on activity in a novel environment and showed that the deprivation effects of Exp I were masked by the response to the new setting. In Exp III, measures of aggression toward intruders of each species were recorded from resident fish of both species under 3 levels of food deprivation. Both species were more aggressive toward conspecifics, and bluegills were more aggressive overall. Aggression was significantly affected by food deprivation, with the effects dependent on the species making up the pair. Theories of motivational summation, generalized drive, and activity-mediated aggression are seen as inadequate to explain the differential effects of hunger on the 3 behavioral categories observed. A dynamic boundary-state model of behavior was, however, found to predict the motivational interactions observed between distinct behavioral control systems. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fas (CD95) participates in peripheral T cell deletion and associated apoptosis in vivo

Following exposure to some types of antigen (superantigens), responsive T cells expand and then decline in numbers, a phenomenon that has been called 'peripheral deletion'. This process may play a role in limiting autoimmune reactions and in the maintenance of immune homeostasis. Here we describe experiments on peripheral deletion in mice carrying the lpr/lpr defect, which has been shown to be due to defective production of the CD95/Fas molecule. Young lpr/lpr mice with no apparent immunologic abnormalities display a defect in bacterial superantigen-induced peripheral deletion. Apoptotic death of the expanded T cell population associated with such peripheral deletion. Apoptotic death of the expanded T cell population associated with such peripheral deletion in normal animals is dramatically reduced in the mutant mice. Further, the levels of Fas on responding cells in normal mice increases and decreases together with increases and decreases in cell numbers, suggesting that cells with the highest levels of Fas are preferentially deleted. These observations are consistent with the known ability of CD95 to transduce a signal leading to apoptosis, and they implicate this signal transduction pathway in peripheral deletion. In contrast, bacterial superantigen-induced deletion of thymocytes appears to be fully functional in these mice, and thus Fas/APO-1 does not appear to be required for this process. Further, antibody ligation of the TCR on activated T cells from normal or young lpr/lpr mice can induce apoptosis and therefore under some circumstances this phenomenon is not dependent upon CD95/Fas. Thus, to avoid autoreactivity and ensure immune homeostasis, several different apoptotic mechanisms exist in peripheral T lymphocytes, only some of which involve Fas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Urinary total isothiocyanate (ITC) in a population-based sample of middle-aged and older Chinese in Singapore: relationship with dietary total ITC and glutathione S-transferase M1/T1/P1 genotypes

Isothiocyanates (ITCs), degradation products of glucosinolates (which occur naturally in a variety of cruciferous vegetables), have been shown to exhibit chemopreventive activity. These compounds are metabolized in vivo to form the corresponding dithiocarbamates, which are the major urinary metabolites of ITCs, by a pathway involving the glutathione S-transferase (GST) class of enzymes. Using a newly developed assay that measures total ITC (primarily ITC conjugates) in urine, we examined the relationships between cruciferous vegetable intake (obtained from a food frequency/portion size questionnaire administered in person); dietary total ITC level; GSTM1, GSTT1, and GSTP1 genotypes; and levels of total ITC in spot urine samples collected from 246 Singapore Chinese (111 men and 135 women), ages 45-74 years, who are participants of the Singapore Cohort Study on diet and cancer. Consumption level of cruciferous vegetables was high in study subjects (mean consumption = 345 times per year, mean daily intake = 40.6 g), which was >3 times the comparable level of intake in the United States. Mean daily intake of total ITC among study subjects was 9.1 micromol, and there was a 2.5-fold difference between the 25th and 75th percentile values. Seventy-three % of study subjects tested positive for ITC in urine, and there was a 4-fold difference between the 25th and 75th percentile values among the positive subjects. There was a highly significant positive association between dietary intake and urinary excretion levels of total ITC (two-sided P = 0.0003) that was stronger than the association between overall cruciferous vegetable intake and urinary ITC level, which also was statistically significant (P = 0.0004). There was no difference in urinary ITC levels between GSTM1-null and GSTM1-positive study subjects (P = 0.61) or between subjects with differing GSTP1 genotypes (P = 0.77), but urinary excretion of ITC was significantly higher among GSTT1-positive subjects, relative to GSTT1-null subjects (P = 0.006). The strength of the association between GSTT1 genotype and urinary total ITC level was highly dependent on the level of cruciferous vegetable consumption (or dietary ITC level) in study subjects. Among subjects in the lowest tertile of cruciferous vegetable intake, there was little evidence of an association between GSTT1 genotype and urinary total ITC level (P = 0.67). In contrast, there was a strong and statistically significant association between GSTT1 genotype and urinary total ITC among subjects in the highest tertile of cruciferous vegetable intake (P = 0.02), whereas those in the middle tertile of cruciferous vegetable consumption exhibited an association of intermediate strength (P = 0.04). These results suggest the presence of GSTT1 inducers in cruciferous vegetables.