Sildenafil improves the beneficial haemodynamic effects of intravenous nitrite infusion during acute pulmonary embolism

Acute pulmonary embolism produces acute pulmonary hypertension, which can be counteracted by activating the nitric oxide-cyclic guanosine 3`,5`-monophosphate (cGMP) pathway. While previous studies have shown that sildenafil (an inhibitor of cGMP-specific phosphodiesterase type 5) or nitrite (a storage molecule for nitric oxide) produces beneficial effects during acute pulmonary embolism, no previous study has examined whether the combination of these drugs can produce additive effects. Here, we expand previous findings and examine whether sildenafil enhances the beneficial haemodynamic effects produced by a low-dose infusion of nitrite in a dog model of acute pulmonary embolism. Haemodynamic and arterial blood gas evaluations were performed in non-embolized dogs treated with saline (n = 4), and in embolized dogs (intravenous injections of microspheres) that received nitrite (6.75 mu mol/kg intravenously over 15 min. followed by 0.28 mu mol/kg/min.) and sildenafil (0.25 mg/kg over 30 min.; n = 8), or nitrite followed by saline (n = 8), or saline followed by sildenafil (n = 7), or only saline (n = 8). Plasma thiobarbituric acid-reactive substances (TBARS) concentrations were determined using a fluorometric method. Acute pulmonary embolism increased pulmonary artery pressure by similar to 24 mmHg. While the infusion of nitrite or sildenafil infusions reversed this increase by similar to 42% (both P < 0.05), the combined infusion of both drugs reversed this increase by similar to 58% (P < 0.05). Similar effects were seen on the pulmonary vascular resistance index. Nitrite or sildenafil alone produced no significant hypotension. However, the combined infusion of both drugs caused transient hypotension (P < 0.05). Both dugs, either alone or combined, blunted the increase in TBARS concentrations caused by acute pulmonary embolism (all P < 0.05). These results suggest that sildenafil improves the beneficial haemodynamic effects of nitrite during acute pulmonary embolism.

The involvement of CD4(+)CD25(+) T cells in the acute phase of Trypanosoma cruzi infection

The infection with Trypanosoma cruzi leads to a vigorous and apparently uncontrolled inflammatory response in the heart. Although the parasites trigger specific immune response, the infection is not completely cleared out, a phenomenon that in other parasitic infections has been attributed to CD4(+)CD25(+) T cells (Tregs). Then, we examined the role of natural Tregs and its signaling through CD25 and GITR in the resistance against infection with T. cruzi. Mice were treated with mAb against CD25 and GITR and the parasitemia, mortality and heart pathology analyzed. First, we demonstrated that CD4(+)CD25(+)GITR(+)Foxp3(+) T cells migrate to the heart of infected mice. The treatment with anti-CD25 or anti-GITR resulted in increased mortality of these infected animals. Moreover, the treatment with anti-GITR enhanced the myocarditis, with increased migration of CD4(+), CD8(+), and CCR5(+) leukocytes, TNF-alpha production, and tissue parasitism, although it did not change the systemic nitric oxide synthesis. These data showed a limited role for CD25 signaling in controlling the inflammatory response during this protozoan infection. Also, the data suggested that signaling through GITR is determinant to control of the heart inflammation, parasite replication, and host resistance against the infection. (C) 2008 Elsevier Masson SAS. All rights reserved.

Determination of P-glycoprotein, MDR-related protein 1, breast cancer resistance protein, and lung-resistance protein expression in leukemic stem cells of acute myeloid leukemia

Background: The most primitive leukemic precursor in acute myeloid leukemia (AML) is thought to be the leukemic stem cell (LSC), which retains the properties of self-renewal and high proliferative capacity and quiescence of the hematopoietic stem cell. LSC seems to be immunophenotypically distinct and more resistant to chemotherapy than the more committed blasts. Considering that the multidrug resistance (MDR) constitutive expression may be a barrier to therapy in AML, we have investigated whether various MDR transporters were differentially expressed at the protein level by different leukemic subsets. Methods: The relative expression of the drug-efflux pumps P-gp, MRP, LRP, and BCRP was evaluated by mean fluorescence index (MFI) and the Kolmogorov-Smirnov analysis (D values) in five leukemic subpopulations: CD34(+)CD38(-)CD123(+) (LSCs), CD34(+)CD38(+)CD123(-), CD34(+)CD38(+)CD123(+), CD34(+)CD38(+)CD123(-), and CD34(-) mature cells in 26 bone marrow samples of CD34(+) AML cases. Results: The comparison between the two more immature subsets (LSC versus CD34(+)CD38(-)CD123(-) cells) revealed a higher P-gp, MRP, and LRP expression in LSCs. The comparative analysis between LSCs and subsets of intermediate maturation (CD34(+)CD38(+)) demonstrated the higher BCRP expression in the LSCs. In addition, P-gp expression was also significantly higher in the LSC compared to CD34(+)CD38(+)CD123(-) subpopulation. Finally, the comparative analysis between LSC and the most mature subset (CD34(-)) revealed higher MRP and LRP and lower P-gp expression in the LSCs. Conclusions: Considering the cellular heterogeneity of AML, the higher MDR transporters expression at the most immature, self-renewable, and quiescent LSC population reinforces that MDR is one of the mechanisms responsible for treatment failure. (C) 2008 Clinical Cytometry Society.

Hemodynamic effects of inducible nitric oxide synthase inhibition combined with sildenafil during acute pulmonary embolism

While endogenous nitric oxide (NO) may be relevant to the beneficial hemodynamic effects produced by sildenafil during acute pulmonary embolism (APE), huge amounts of inducible NO synthase (iNOS)derived NO may contribute to lung injury. We hypothesized that iNOS inhibition with S-methylisothiourea could attenuate APE-induced increases in oxidative stress and pulmonary hypertension and, therefore, could improve the beneficial hemodynamic and antioxidant effects produced by sildenafil during APE. Hemodynamic evaluations were performed in non-embolized dogs treated with saline (n = 4), S-methylisothiourea (0.01 mg/kg followed by 0.5 mg/kg/h, n = 4), sildenafil (0.3 mg/kg, n = 4), or S-methylisothiourea followed by sildenafil (n = 4), and in dogs that received the same drugs and were embolized with silicon microspheres (n = 8 for each group). Plasma nitrite/nitrate (NOx) and thiobarbituric acid reactive substances (TBARS) concentrations were determined by Griess and a fluorometric assay, respectively. APE increased mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance index (PVRI) by 25 +/- 1.7 mm Hg and by 941 +/- 34 dyn s cm(-5) m(-2), respectively. S-methylisothiourea neither attenuated APE-induced pulmonary hypertension, nor enhanced the beneficial hemodynamic effects produced by sildenafil after APE (>50% reduction in pulmonary vascular resistance). While sildenafil produced no change in plasma NOx concentrations, S-methylisothiourea alone or combined with sildenafil blunted APE-induced increases in NOx concentrations. Both drugs, either alone or combined, produced antioxidant effects. In conclusion, although iNOS-derived NO may play a key role in APE-induced oxidative stress, our results suggest that the iNOS inhibitor S-methylisothiourea neither attenuates APE-induced pulmonary hypertension, nor enhances the beneficial hemodynamic effects produced by sildenafil. (C) 2010 Elsevier Inc. All rights reserved.

Differential expression of HDAC3, HDAC7 and HDAC9 is associated with prognosis and survival in childhood acute lymphoblastic leukaemia

Altered expression of histone deacetylases (HDACs) is a common feature in several human malignancies and may represent an interesting target for cancer treatment, including haematological malignancies. We evaluated the mRNA gene expression profile of 12 HDAC genes by quantitative real-time polymerase chain reaction in 94 consecutive childhood acute lymphoblastic leukaemia (ALL) samples and its association with clinical/biological features and survival. ALL samples showed higher expression levels of HDAC2, HDAC3, HDAC8, HDAC6 and HDAC7 when compared to normal bone marrow samples. HDAC1 and HDAC4 showed high expression in T-ALL and HDAC5 was highly expressed in B-lineage ALL. Higher than median expression levels of HDAC3 were associated with a significantly lower 5-year event-free survival (EFS) in the overall group of patients (P = 0.03) and in T-ALL patients (P = 0.01). HDAC7 and HADC9 expression levels higher than median were associated with a lower 5-year EFS in the overall group (P = 0.04 and P = 0.003, respectively) and in B-lineage CD10-positive patients (P = 0.009 and P = 0.005, respectively). Our data suggest that higher expression of HDAC7 and HDAC9 is associated with poor prognosis in childhood ALL and could be promising therapeutic targets for the treatment of refractory childhood ALL.

Lower respiratory tract infections among human immunodeficiency virus-exposed, uninfected infants

Objectives: To evaluate whether maternal HIV disease severity during pregnancy is associated with an increased likelihood of lower respiratory tract infections (LRTIs) in HIV-exposed, uninfected infants. Methods: HIV-exposed, uninfected, singleton, term infants enrolled in the NISDI Perinatal Study, with birth weight >2500 g were followed from birth until 6 months of age. LRTI diagnoses, hospitalizations, and associated factors were assessed. Results: Of 547 infants, 103 (18.8%) experienced 116 episodes of LRTI (incidence = 0.84 LRTIs/100 child-weeks). Most (81%) episodes were bronchiolitis. Forty-nine (9.0%) infants were hospitalized at least once with an LRTI. There were 53 hospitalizations (45.7%) for 116 LRTI episodes. None of these infants were breastfed. The odds of LRTI in infants whose mothers had CD4% <14 at enrollment were 4.4 times those of infants whose mothers had CD4% >= 29 (p = 0.003). The odds of LRTI in infants with a CD4+ count (cells/ mm(3)) <750 at hospital discharge were 16.0 times those of infants with CD4+ >= 750 (p = 0.002). Maternal CD4+ decline and infant hemoglobin at the 6-12 week visit were associated with infant LRTIs after 6-12 weeks and before 6 months of age. Conclusions: Acute bronchiolitis is common and frequently severe among HIV-exposed, uninfected infants aged 6 months or less. Lower maternal and infant CD4+ values were associated with a higher risk of infant LRTIs. Further understanding of the immunological mechanisms of severe LRTIs is needed. (C) 2010 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Low mRNA Expression of the Apoptosis-Related Genes CASP3, CASP8, and FAS Is Associated With Low Induction Treatment Response in Childhood Acute Lymphoblastic Leukemia (ALL)

Background. Defects in apoptosis signaling have been considered to be responsible for treatment failure in many types of cancer, although with controversial results. The objective of the present study was to assess the expression profile of key apoptosis-related genes in terms of clinical and biological variables and of the survival of children with acute lymphoblastic leukemia (ALL). Procedure. The levels of mRNA expression of the apoptosis-related genes CASP3, CASP8, CASP9, FAS, and BCL2 were analyzed by quantitative real-time PCR in consecutive samples from 139 consecutive children with ALL at diagnosis treated by the Brazilian protocol (GBTLI-ALL 99). Gene expression levels and clinical and biological features were compared by the Mann-Whitney test. Event-free survival (EFS) was calculated by Kaplan-Meier plots and log-rank test. Results. A significant correlation was detected between CASP3, CASP8, CASP9, and FAS expression levels (P<0.01) in ALL samples. Higher levels of BCL2 were significantly associated with white blood cell (WBC) count <50,000/mm(3) at diagnosis (P=0.01) and low risk group classification (P=0.008). Lower expression levels of CASP3, CASP8 and FAS gene were associated with a poor response at day 7 according the GBTLI-ALL 99 protocol (P=0.03, P=0.02 and P=0.008, respectively). There was a relationship between FAS gene expression lower than the 75th percentile and lower 5-year EFS (P=0.02). Conclusion. These findings suggest an association between lower expression levels of the pro-apoptotic genes and a poor response to induction therapy at day 7 and prognosis in childhood ALL. Pediatr Blood Cancer 2010;55:100-107. (C) 2010 Wiley-Liss, Inc.

Septic shock caused by Plesiomonas shigelloides in a patient with sickle beta-zero thalassemia

Invasive infection and extraintestinal complications are rarely caused by Plesiomonas shigelloides, a water-borne bacterium belonging to the Vibrionaceae family. We report a case of a 16-year-old female patient with sickle beta-zero thalassemia who survived septic shock caused by P. shigelloides associated with secondary acute respiratory distress syndrome and disseminated intravascular coagulation. Treatment with a carbapenem was successful, and the patient recovered without any sequelae. The previous reports of P. shigelloides sepsis are cited, and possible pathogenic mechanisms are discussed. (Heart Lung (R) 2010;39:335-339.)

Comparison of MB fraction of creatine kinase mass and troponin I serum levels with necropsy findings in acute myocardial infarction

Serum levels of troponin and heart-related fraction of creatine kinase (CK-MB) mass are used as diagnostic and prognostic criteria in myocardial infarction, but the relation between those levels and-the necropsy-determined size of necrosis has not been tested in human beings. In this retrospective study, 1-cm-thick transverse sections of the ventricles were cut from the base to the apex in the necropsy hearts of 27 patients aged 47 to 86 years (mean 66, median 69; 19 men). Total and necrotic areas were measured using a computer-linked image analysis system. The weights of the necrotic areas were also calculated. The correlations of the areas and weights of necrotic myocardium with the highest serum values of CK-MB mass and troponin 1, which had been quantified during life by chemiluminescence immunoassays, were verified by Pearson`s test; results were considered significant at p <= 50.05. Significant correlations were detected between CK-MB mass peak and infarct size (r = 0.63, p < 0.01) and weight (r = 0.69, p < 0.01) and between CK-MB mass and highest troponin level (r = 0.73, p < 0.01); however, the correlations between highest troponin level and myocardial infarct size (r = 0.31, p = 0.11) and weight (r = 0.35, p = 0.07) were small and nonsignificant. In conclusion, despite the well-established role of serum levels of troponin as a diagnostic tool for myocardial infarction, their highest values showed poor correlations with the extent of infarct. In contrast, the highest serum level of CK-MB mass was well correlated with myocardial infarct size. (c) 2008 Elsevier Inc. All rights reserved.

Hemodynamic effects of PEEP in a porcine model of HCl-induced mild acute lung injury

Positive end-expiratory pressure (PEEP) and sustained inspiratory insufflations (SI) during acute lung injury (ALI) are suggested to improve oxygenation and respiratory mechanics. We aimed to investigate the hemodynamic effects of PEEP with and without alveolar recruiting maneuver in a mild ALI model induced by inhalation of hydrochloric acid. Thirty-two pigs were randomly allocated into four groups (Control-PEEP, Control-SI, ALI-PEEP and ALI-SI). ALI was induced by intratracheal instillation of hydrochloric acid. PEEP values were progressively increased and decreased from 5, 10, 15 and 20 cmH(2)O in all groups. Three SIs maneuvers of 30 cmH(2)O for 20 s were applied to the assignable groups between each PEEP level. Transesophageal echocardiography (TEE), global hemodynamics, oxygenation indexes and gastric tonometry were measured 5 min after the maneuvers had been concluded and at each established value of PEEP (5, 10, 15 and 20 cmH(2)O). The cardiac index, ejection fraction and end-diastolic volume of right ventricle were significantly (P < 0.001) decreased with PEEP in both Control and ALI groups. Left ventricle echocardiography showed a significant decrease in end-diastolic volume at 20 cmH(2)O of PEEP (P < 0.001). SIs did not exert any significant hemodynamic effects either early (after 5 min) or late (after 3 h). In a mild ALI model induced by inhalation of hydrochloric acid, significant hemodynamic impairment characterized by cardiac function deterioration occurred during PEEP increment, but SI, probably due to low applied values (30 cmH(2)O), did not exert further negative hemodynamic effects. PEEP should be used cautiously in ALI caused by acid gastric content inhalation.

Experimental infection with Rangelia vitalii in dogs: Acute phase, parasitemia, biological cycle, clinical-pathological aspects and treatment

Recently we conducted the molecular characterization of Rangelia vitalii, a protozoan with high pathogenicity for young dogs in southern Brazil. To date, the descriptions of the disease have been restricted to natural infection cases. Therefore, this study aimed to evaluate the parasitemia, biological cycles and clinical-pathological findings in dogs experimentally infected with R. vitalii in the acute phase of disease, and also aimed to test a therapeutic protocol based on the diminazene aceturate. For this study, we used 12 young dogs (females), separated into two groups. Group A was composed of healthy dogs, not-infected (n = 5), and Group B consisted of animals infected with R. vitalii (n = 7). After infection, the animals were monitored by blood smear examinations, which showed intra-erythrocytic forms of the parasite 5 days post-infection (PI). Parasitemia increased progressively in these animals and had the highest peak of circulating parasites between 9 and 11 days PI. Subsequently, the parasitemia reduced and the protozoan was seen inside the leukocytes in days 17, 19 and 21 PI. The most prominent clinical signs observed at the 20 day PI of experiment were lethargy, fever and anorexia. We observed a decrease of hematocrit of infected animals compared with not-infected dogs, featuring a moderate anemia. Pathological evaluation of one dog in Group B at day 21 PI revealed splenomegaly, hepatomegaly, lymphadenopathy, and hemorrhages at necropsy. Histological examination showed only follicular hyperplasia in the spleen and lymph nodes, and the etiologic agent in the vascular endothelium. At 21 days PI, it was performed the treatment of dogs in Group B (n = 6) with a single dose of diminazene aceturate, which showed a curative efficacy of 100% in cleaning R. vitalii from blood of infected dogs. (C) 2011 Elsevier Inc. All rights reserved.

Ehrlichia canis in dogs attended in a veterinary hospital from Botucatu, Sao Paulo State, Brazil

This study investigated the etiology of canine ehrlichiosis and possible clinical and epidemiological data associated with the infection in 70 dogs suspect of ehrlichiosis attended at the Veterinary Hospital of the Sao Paulo State University in Botucatu city during 2001 and 2002. Dogs were evaluated by clinical-epidemiological and hematological data and molecular analysis by partial amplification and DNA sequencing of the ehrlichial dsb gene. E. canes DNA was amplified and sequenced in 28 (40.0%) dogs. Dogs younger than 12 months old showed significantly higher infection rates (65.0%; P < 0.05). Diarrhea, apathy, and anorexia were the major clinical signs observed in 55.2% (P = 0.05), 47.0% (P > 0.05), and 42.4% (P > 0.05) of the PCR-positive dogs, respectively. Twenty-five anemic (<5.5 x 10(6) RBC.mu L(-1)), and 8 leukopenic (<5.5 x 10(3) WBC.mu L(-1)) dogs were PCR-positive (P > 0.05). All 28 PCR-positive dogs showed thrombocytopenia (<175 x 10(3) platelets.mu L(-1)) and revealed statistical significance (P < 0.05). E. canis was the only Ehrlichia species found in dogs in the studied region, with higher infection rates in younger dogs, and statistically associated with thrombocytopenia.

Amitriptyline and Acute Inflammation: A Study Using Intravital Microscopy and the Carrageenan-Induced Paw Edema Model

Background/Aims: Antidepressants are reported to exhibit antiinflammatory effects. However, mechanisms involved in this action have not been elucidated. Thus, the objectives of the present study were (a) to evaluate the effects of amitriptyline on the acute inflammatory process, and (b) to investigate the participation of alpha(1)-adrenergic receptors and glucocorticoids as possible mechanisms implicated in the amitriptyline action on inflammation. Methods and Results: Single and multiple doses of amitriptyline were administered to rats submitted to the carrageenan-induced paw edema model. The results showed a significant antiedematous reaction to amitriptyline, mainly when administered at each elimination half-life. The next step was to evaluate its effects on leukocyte behavior, using intravital microscopy. Amitriptyline produced a significant effect on leukocyte behavior. To investigate possible mechanisms involved, a glucocorticoid receptor antagonist (RU-486) and an alpha(1)-adrenergic receptor antagonist (prazosin) were used. RU-486 administration lacked the ability to decrease the amitriptyline antiinflammatory effects in the carrageenan-induced paw edema model. Prazosin pretreatment potentiated the amitriptyline antiinflammatory effect without presenting an effect per se. Conclusion:The present study shows the ability of amitriptyline to decrease edema and affect leukocyte behavior in an acute inflammatory process; and, for the first time to our knowledge, we suggest the involvement of alpha(1)-adrenoceptors in the antiinflammatory effects of amitriptyline. Copyright (C) 2010 S. Karger AG, Basel

Behavioral effects of acute stimulation of kappa-opioid receptors during lactation

The behavioral effects of the K-opioid receptor agonist U69593 were examined in lactating rats. On day 5 of lactation, animals were treated with 0.1 mg/kg of U69593 to determine whether it influences general activity and maternal latencies toward pups. Because little attention has been given to the possibility that pre-mating treatment with morphine may modulate the response to K-opioid receptor stimulation, another group of animals was submitted to the same acute challenge after abrupt withdrawal from repeated treatment with morphine sulfate during the pre-mating period (5 mg/kg on alternate days for a total of five doses). Acute F;opioid stimulation reduced total locomotion, rearing frequency, and time spent self-grooming and increased immobility duration. These K agonist effects were not observed in animals pretreated with morphine. Similarly, latencies to retrieve pups were longer only in animals pretreated with saline and challenged acutely with U69593. None of these effects were observed in morphine sulfate-pretreated animals. The present results suggest that pre-mating repeated exposure to morphine produces a tolerance-like effect on behavioral responses to low-dose K-opioid receptor stimulation in active reproductive females. (c) 2008 Elsevier Inc. All rights reserved.