Hemolytic activity of Trichomonas vaginalis and Tritrichomonas foetus

The hemolytic activity of live isolates and clones of Trichomonas vaginalis and Tritrichomonas foetus was investigated. The isolates were tested against human erythrocytes. No hemolytic activity was detected by the isolates of T. foetus. Whereas the isolates of T. vaginalis lysed erythrocytes from all human blood groups. No hemolysin released by the parasites could be detected. Our preliminary results suggest that hemolysis depend on the susceptibility of red cell membranes to destabilization and the intervention of cell surface receptors as a mechanism of the hemolytic activity. The mechanism could be subject to strain-species-genera specific variation of trichomonads. The hemolytic activity of T. vaginalis is not due to a hemolysin or to a product of its metabolism. Pretreatment of trichomonads with concanavalin A reduced levels of hemolysis by 40%.

The association of genetic markers and malaria infection in the Brazilian Western Amazonian region

Almost all individuals (182) belonging to an Amazonian riverine population (Portuchuelo, RO, Brazil) were investigated for ascertaining data on epidemiological aspects of malaria. Thirteen genetic blood polymorphisms were investigated (ABO, MNSs, Rh, Kell, and Duffy systems, haptoglobins, hemoglobins, and the enzymes glucose-6-phosphate dehydrogenase, glyoxalase, phosphoglucomutase, carbonic anhydrase, red cell acid phosphatase, and esterase D). The results indicated that the Duffy system is associated with susceptibility to malaria, as observed in other endemic areas. Moreover, suggestions also arose indicating that the EsD and Rh loci may be significantly associated with resistance to malaria. If statistical type II errors and sample stratification could be ruled out, hypotheses on the existence of a causal mechanism or an unknown closely linked locus involved in susceptibility to malaria infection may explain the present findings.

Survival, prognostic factors and rates of leukemic transformation in 381 untreated patients with MDS and del(5q): a multicenter study.

Myelodysplastic syndromes (MDS) with del(5q) are considered to have a benign course of the disease. In order to address the issue of the propensity of those patients to progress to acute myeloid leukemia (AML), data on 381 untreated patients with MDS and del(5q) characterized by low or intermediate I International Prognostic Scoring System (IPSS) risk score were collected from nine centers and registries. Median survival of the entire group was 74 months. Transfusion-dependent patients had a median survival of 44 months vs 97 months for transfusion-independent patients (P<0.0001). Transfusion need at diagnosis was the most important patient characteristic for survival. Of the 381 patients, 48 (12.6%) progressed to AML. The cumulative progression rate calculated using the Kaplan-Meier method was 4.9% at 2 years and 17.6% at 5 years. Factors associated with the risk of AML transformation were high-risk World Health Organization adapted Prognostic Scoring System (WPSS) score, marrow blast count >5% and red-cell transfusion dependency at diagnosis. In conclusion, patients with MDS and del(5q) are facing a considerable risk of AML transformation. More detailed cytogenetic and molecular studies may help to identify the patients at risk of progression.

Age over 40 years increases the failure rate of non-operative management of blunt splenic injuries

Objective: Non-operative management (NOM) of blunt splenic injuries (BSI) is nowadays considered the standard treatment. The study aimed to determine the criteria applied for NOM and to identify risk factors for its failure. Methods: Review of all adult patients with BSI treated at the University Hospital Bern, Switzerland, between 2000 and 2008. Results: There were 206 patients (146 men, 70·9%) with a mean age of 38·2 ± 19·1 years and an Injury Severity Score of 30·9 ± 11·6. The American Association for the Surgery of Trauma classification of the splenic injury was: grade I, n=43 (20·9%); grade II, n=52 (25·2%); grade III, n=60 (29·1%); grade IV, n=42 (20·4%) and grade V, n=9 (4·4%). 47 patients (22·8%) required immediate surgery. Five or more units of red cell transfusions (P<0·001), Glasgow Coma Scale<11 (P=0·009) and age ≥55 years (P=0·038) were associated with primary operative management (OM). 159 patients (77·2%) qualified for NOM, which was successful in 89·9% (143/159). The overall splenic salvage rate was 69·4% (143/206). Multivariate analysis found age ≥40 years to be the only factor independently related to the failure of NOM (P=0·001). Conclusion: Advanced age is associated with an increased failure rate ofNOM in patients with BSI.

Analysis of malaria associated genetic traits in Cabo Verde, a melting pot of European and sub Saharan settlers

Malaria has occurred in the Cabo Verde archipelago with epidemic characteristics since its colonization. Nowadays, it occurs in Santiago Island alone and though prophylaxis is not recommended by the World Health Organization, studies have highlight the prospect of malaria becoming a serious public health problem as a result of the presence of antimalarial drug resistance associated with mutations in the parasite populations and underscore the need for tighter surveillance. Despite the presumptive weak immune status of the population, severe symptoms of malaria are not observed and many people present a subclinical course of the disease. No data on the prevalence of sicklecell trait and red cell glucose-6-phosphate dehydrogenase deficiency (two classical genetic factors associated with resistance to severe malaria) were available for the Cabo Verde archipelago and, therefore, we studied the low morbidity from malaria in relation to the particular genetic characteristics of the human host population. We also included the analysis of the pyruvate kinase deficiency associated gene, reported as putatively associated with resistance to the disease. Allelic frequencies of the polymorphisms examined are closer to European than to African populations and no malaria selection signatures were found. No association was found between the analyzed human factors and infection but one result is of high interest: a linkage disequilibrium test revealed an association of distant loci in the PKLR gene and adjacent regions, only in non-infected individuals. This could mean a more conserved gene region selected in association to protection against the infection and/or the disease.

Advanced age increases the failure rate of non-operative management of blunt splenic injuries

Introduction: Non-operative management (NOM) of blunt splenic injuries in hemodynamically stable patients is nowadays considered the standard treatment. Material and Methods: The aim was to clarify the criteria used for primary operative management (OM) and planned NOM. Furthermore, the study aimed to identify risk factors for failure of NOM. All adult patients with blunt splenic injuries treated from 2000-2008 were reviewed and a logistic regression analysis employed. Results: There were 206 patients (146 men, 70.9%). Mean age was 38.2 ± 19.1 years. The mean Injury Severity Score (ISS) was 30.9 ± 11.6. The American Association for the Surgery of Trauma (AAST) classification of the splenic injury was: grade I, n = 43 (20.9%); grade II, n = 52 (25.2%); grade III, n = 60 (29.1%), grade IV, n = 42 (20.4%) and grade V, n = 9 (4.4%). 47 patients (22.8%) required immediate surgery (OM). More than 5 units of red cell transfusions (odds ratio [OR] 13.72, P < 0.001), a Glasgow Coma Scale < 11 (OR 9.88, P = 0.009) and age ? 55 years (OR 3.29, P = 0.038) were associated with primary OM. 159 patients (77.2%) qualified for a non-surgical approach (NOM), which was successful in 89.9% (143/159). The overall splenic salvage rate amounted to 69.4% (143/206). Multiple logistic regression analysis found age ? 40 years to be the only factor significantly and independently related to the failure of NOM (OR 13.58, P = 0.001). Conclusion: Advanced age is associated with an increased failure rate of NOM in patients with blunt splenic injuries.

Fecundity and survival in relation to resistance to oxidative stress in a free-living bird.

Major life history traits, such as fecundity and survival, have been consistently demonstrated to covary positively in nature, some individuals having more resources than others to allocate to all aspects of their life history. Yet, little is known about which resources (or state variables) may account for such covariation. Reactive oxygen species (ROS) are natural by-products of metabolism and, when ROS production exceeds antioxidant defenses, organisms are exposed to oxidative stress that can have deleterious effects on their fecundity and survival. Using a wild, long-lived bird, the Alpine Swift (Apus melba), we examined whether individual red cell resistance to oxidative stress covaried with fecundity and survival. We found that males that survived to the next breeding season tended to be more resistant to oxidative stress, and females with higher resistance to oxidative stress laid larger clutches. Furthermore, the eggs of females with low resistance to oxidative stress were less likely to hatch than those of females with high resistance to oxidative stress. By swapping entire clutches at clutch completion, we then demonstrated that hatching failure was related to the production of low-quality eggs by females with low resistance to oxidative stress, rather than to inadequate parental care during incubation. Although male and female resistance to oxidative stress covaried with age, the relationships among oxidative stress, survival, and fecundity occurred independently of chronological age. Overall, our study suggests that oxidative stress may play a significant role in shaping fecundity and survival in the wild. It further suggests that the nature of the covariation between resistance to oxidative stress and life history traits is sex specific, high resistance to oxidative stress covarying primarily with fecundity in females and with survival in males.

Médecine d'urgence [Emergency medicine: updates 2013].

New evidences published this year are susceptible to change the management of several medical emergencies. Combined antiplatelet therapy might be beneficial for the management of TIA or minor stroke and rapid blood pressure lowering might improve the outcome in patients with intracerebral hemorrhage. A restrictive red cell transfusion strategy is indicated in case of upper digestive bleeding and coagulation factors concentrates are superior to fresh frozen plasma for urgent warfarin reversal. Prolonged systemic steroid therapy is not warranted in case of acute exacerbation of BPCO, and iterative physiotherapy is not beneficial after acute whiplash. Finally, family presence during cardiopulmonary resuscitation may reduce post-traumatic stress disorder among relatives.

Grape epicatechin conjugates prevent erythrocyte membrane protein oxidation

Epicatechin conjugates obtained from grape have shown antioxidant activity in various systems. However, how these conjugates exert their antioxidant benefits has not been widely studied. We assessed the activity of epicatechin and epicatechin conjugates on the erythrocyte membrane in the presence and absence of a peroxyl radical initiator, to increase our understanding of their mechanisms. Thus, we studied cell membrane fluidity by fluorescence anisotropy measurements, morphology of erythrocytes by scanning electron microscopy, and finally, red cell membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Our data showed that incubation of red cells in the presence of epicatechin derivatives altered membrane fluidity and erythrocyte morphology but not the membrane protein pattern. The presence in the medium of the peroxyl radical initiator 2,2′-azobis(amidinopropane) dihydrochloride (AAPH) resulted in membrane disruptions at all levels analyzed, causing changes in membrane fluidity, cell morphology, and protein degradation. The presence of antioxidants avoided protein oxidation, indicating that the interaction of epicatechin conjugates with the lipid bilayer might reduce the accessibility of AAPH to membranes, which could explain in part the inhibitory ability of these compounds against hemolysis induced by peroxidative insult.

Médecine d'urgence [Emergency medicine: updates 2013].

New evidences published this year are susceptible to change the management of several medical emergencies. Combined antiplatelet therapy might be beneficial for the management of TIA or minor stroke and rapid blood pressure lowering might improve the outcome in patients with intracerebral hemorrhage. A restrictive red cell transfusion strategy is indicated in case of upper digestive bleeding and coagulation factors concentrates are superior to fresh frozen plasma for urgent warfarin reversal. Prolonged systemic steroid therapy is not warranted in case of acute exacerbation of BPCO, and iterative physiotherapy is not beneficial after acute whiplash. Finally, family presence during cardiopulmonary resuscitation may reduce post-traumatic stress disorder among relatives.

A new allele of peptidase-B in cattle

Electrophoretic analyses of peptidase-B were carried out on red cell hemolysates from Holstein, Mantiqueira and Gyr cattle, using cornstarch, known in Brazil as Penetrose-30. We describe a new peptidase-B allele, denoted Pep-B1, in Mantiqueira cattle, belonging to the Bos taurus group, which are the result of a cross of native cattle of Portuguese origin introduced in Brazil during colonial times (16th century) with Holstein and Caracu cattle. The genetic control of peptidase-B was determined by typing parents and progeny segregating for all three alleles, confirming that peptidase B is controlled by a single autosomal locus with three codominant alleles, denoted Pep-B1, Pep-B2 and Pep-B3 The use of the citrate-phosphate buffer system, at pH 5.9, on 14% gel, under the electrophoretic conditions standardized in this study permitted good visualization of all peptidase-B variants.

Clinical results of the use of mitotane for adrenocortical carcinoma

Mitotane (o,p'-DDD) acts mainly as an inhibitor of intramitochondrial pregnenolone and cortisol synthesis. Its adrenolytic effect depends on metabolic activation due to conversion to o,p'-DDA and o,p'-DDE. The drug has been used for 40 years in the treatment of adrenocortical carcinoma, mainly its regional and metastatic stage, as an adjuvant to surgical resection of the tumor. In the medical literature there are controversial opinions about its efficacy for the treatment of adrenocortical carcinoma. In our experience, mitotane administered immediately after surgery appeared to be much more efficient than when administered later. We have administered this drug in all cases of microscopically confirmed adrenocortical carcinoma, irrespectively of stage at the time of surgery, for fear of a false too optimistic classification. In our series of 82 patients with adrenocortical carcinoma, 59 patients have been treated with mitotane, 32 of them immediately after surgery, and 27 with a delay of 2 to 24 months. Today there are 18 survivors in the group of patients treated with mitotane soon after the operation and only 6 survivors in the group receiving mitotane with a delay. All patients were simultaneously given replacement therapy. Undesired effects of mitotane administration included increased aminotransferase and alkaline phosphatase activity, decreased white cell, platelet or red cell number, and myasthenia. Furthermore, we used mitotane with good results in Cushing's syndrome of non-malignant origin as pre-treatment before surgery or in long-term treatment for patients with poor tolerance of other adrenal inhibitors.

ß-Spectrin São PauloII, a novel frameshift mutation of the ß-spectrin gene associated with hereditary spherocytosis and instability of the mutant mRNA

Hereditary spherocytosis (HS) is a common inherited anemia characterized by the presence of spherocytic red cells. Defects in several membrane protein genes have been involved in the pathogenesis of HS. ß-Spectrin-related HS seems to be common. We report here a new mutation in the ß-spectrin gene coding region in a patient with hereditary spherocytosis. The patient presented acanthocytosis and spectrin deficiency and, at the DNA level, a novel frameshift mutation leading to HS, i.e., a C deletion at codon 1392 (ß-spectrin São PauloII), exon 20. The mRNA encoding ß-spectrin São PauloII was very unstable and the mutant protein was not detected in the membrane or in other cellular compartments. It is interesting to note that frameshift mutations of the ß-spectrin gene at the 3' end allow the insertion of the mutant protein in the red cell membrane, leading to a defect in the auto-association of the spectrin dimers and consequent elliptocytosis. On the other hand, ß-spectrin São PauloII protein was absent in the red cell membrane, leading to spectrin deficiency, HS and the presence of acanthocytes.

The effects of 2,3-diphosphoglycerate, adenosine triphosphate, and glycosylated hemoglobin on the hemoglobin-oxygen affinity of diabetic patients

The position of the oxygen dissociation curve (ODC) is modulated by 2,3-diphosphoglycerate (2,3-DPG). Decreases in 2,3-DPG concentration within the red cell shift the curve to the left, whereas increases in concentration cause a shift to the right of the ODC. Some earlier studies on diabetic patients have reported that insulin treatment may reduce the red cell concentrations of 2,3-DPG, causing a shift of the ODC to the left, but the reports are contradictory. Three groups were compared in the present study: 1) nondiabetic control individuals (N = 19); 2) insulin-dependent diabetes mellitus (IDDM) patients (on insulin treatment) (N = 19); 3) non-insulin-dependent diabetes mellitus (NIDDM) patients using oral hypoglycemic agents and no insulin treatment (N = 22). The overall position of the ODC was the same for the three groups despite an increase of the glycosylated hemoglobin fraction that was expected to shift the ODC to the left in both groups of diabetic patients (HbA1c: control, 4.6%; IDDM, 10.5%; NIDDM, 9.0%). In IDDM patients, the effect of the glycosylated hemoglobin fraction on the position of the ODC appeared to be counterbalanced by small though statistically significant increases in 2,3-DPG concentration from 2.05 (control) to 2.45 µmol/ml blood (IDDM). Though not statistically significant, an increase of 2,3-DPG also occurred in NIDDM patients, while red cell ATP levels were the same for all groups. The positions of the ODC were the same for control subjects, IDDM and NIDDM patients. Thus, the PO2 at 50% hemoglobin-oxygen saturation was 26.8, 28.2 and 28.5 mmHg for control, IDDM and NIDDM, respectively. In conclusion, our data question the idea of adverse side effects of insulin treatment on oxygen transport. In other words, the shift to the left reported by others to be caused by insulin treatment was not detected.

The secondary alcohol and aglycone metabolites of doxorubicin alter metabolism of human erythrocytes

Anthracyclines, a class of antitumor drugs widely used for the treatment of solid and hematological malignancies, cause a cumulative dose-dependent cardiac toxicity whose biochemical basis is unclear. Recent studies of the role of the metabolites of anthracyclines, i.e., the alcohol metabolite doxorubicinol and aglycone metabolites, have suggested new hypotheses about the mechanisms of anthracycline cardiotoxicity. In the present study, human red blood cells were used as a cell model. Exposure (1 h at 37ºC) of intact human red blood cells to doxorubicinol (40 µM) and to aglycone derivatives of doxorubicin (40 µM) induced, compared with untreated red cells: i) a ~2-fold stimulation of the pentose phosphate pathway (PPP) and ii) a marked inhibition of the red cell antioxidant enzymes, glutathione peroxidase (~20%) and superoxide dismutase (~60%). In contrast to doxorubicin-derived metabolites, doxorubicin itself induced a slighter PPP stimulation (~35%) and this metabolic event was not associated with any alteration in glutathione reductase, glutathione peroxidase, catalase or superoxide dismutase activity. Furthermore, the interaction of hemoglobin with doxorubicin and its metabolites induced a significant increase (~22%) in oxygen affinity compared with hemoglobin incubated without drugs. On the basis of the results obtained in the present study, a new hypothesis, involving doxorubicinol and aglycone metabolites, has been proposed to clarify the mechanisms responsible for the doxorubicin-induced red blood cell toxicity.