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Pelibuey and Katahdin are two the most extensively used hair sheep breeds in tropical regions characterized by high temperatures and humidity. Lactation influences profitability of sheep in dairy and non-dairy production systems. Therefore, the aim of this study was to evaluate the effect of breed and litter size (LS) on milk yield and milk composition of Pelibuey (n = 28) and Katahdin (n = 21) ewes reared under tropical conditions of Mexico. Milk, fat, protein and lactose yields, fat and energy-corrected milk, and fat, protein and lactose percentages were measured for seven weeks. Body weight (BW) of each ewe was measured weekly. Breed effects were significant (P < 0.001) favouring Katahdin breed on all yield traits. Ewes rearing two lambs had higher yields (P < 0.01) for all traits than ewes rearing one lamb. Fat percentage and BW were significantly (P < 0.05) affected by a triple interaction effect of Breed x LS x Week. So, important differences in milk yield and composition among breeds and LS were shown and might be considered in order to improve profitability of sheep production systems under tropical conditions. [ABSTRACT FROM AUTHOR]

Microbial mats from two ponds with different salinities from the saltern of Guerrero Negro ( Mexico) points toward millimeter-scale coherent variations in trace metal ( Me) concentrations ( Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn). Total, HCl-leachable and pyrite-associated Me showed a trend of increasing concentrations with increasing depth suggesting gradual addition of reactive Me probably as a result of metal sulfide precipitation at depth. The trends in Me profiles can be ascribed to the establishment and maintenance of microzones that promote geochemical processes, bacterial population distributions, and differential mass transport within the mats. Degrees of trace metal pyritization (1 ± 1% for Zn to 24 ± 7% for Cd) as well as metals associated with the pyrite fraction (<1.4-36 ± 18 nmol g−1 for Zn and Mn, respectively) were low, as expected from a reactive Fe-limited system like Guerrero Negro. Calculated enrichment factors showed that Ni (2.6 ± 2.1), Co (5.5 ± 4.0), Pb (9.4 ± 7.4), and Cd (57 ± 39) were, on average, enriched in the microbial mats of Guerrero Negro. Natural enrichments of Cd, Pb, and Co in sediments along the coast of Baja California and metabolical requirements of Co and Ni by the predominant cyanobacteria in the Guerrero Negro mats may explain these enrichments. Metal characteristics in microbial mats could be advantageously used as biosignatures to identify their presence in the geological record or in other planetary systems. [ABSTRACT FROM AUTHOR]

Background: Despite novel therapies, multiple myeloma (MM) remains an incurable malignancy, daratumumab (DARA) being a major game changer, may be a good option for treatment., Aimed of the Study: To assess the prescription patterns of DARA in patients with MM in Mexico., Methods: 47 patients with MM were analyzed in 13 different hospitals in Mexico., Results: Five (10.5%) of patients received DARA as first line therapy, 13 (27.5%) as second line, whereas 29 (62%) received its in ≥3 rd line. In 32% DARA was used in combination with dexamethasone, 64% received DARA on a triple combination, and 4% as a 4 drug combination. Eighty three percent of patients had a response, including 32% in complete remission. Progression free survival (PFS) was higher in patients in ISS stage 1, and in patients achieving ≥PR. Overall survival (OS) was lower in patients not achieving ≥PR, in patients having increased LDH, and extramedullary disease. Grade 1-2 infusion related reactions were present in 34%, and grade 3-4 neutropenia and lymphopenia in 25 and 17% of the patients., Conclusions: In Mexico, 62% of patients with MM received DARA as a third or further line of treatment. DARA employed as a doublet or triplet combination is useful in relapsed/refractory patients with tolerable adverse events., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: Vitamin K antagonists (VKA) are a therapeutic alternative in patients with venous thromboembolic disease; however, numerous factors affect their pharmacology., Objective: To evaluate the quality of VKA anticoagulation at three different time periods in Mexico., Methods: Prospective study, nested in patient cohorts at three different clinical scenarios between 2013 and 2019. Outpatients with indication for treatment with VKAs for at least 12 months were included. Patients were managed according to the criteria of the treating physician., Results: Patient general characteristics were similar between groups, except for the VKA indication. The results of 4,148 patients and 38,548 INR assessments were analyzed. The times in therapeutic range during the three phases of the study and pooled data were significantly higher for the anticoagulation clinic. Only the number of patient visits was significantly associated with the results, unlike age, gender, and type of VKA., Conclusions: VKAs are widely used, but it is difficult for therapeutic goals to be achieved, especially in non-specialized clinical services. Creation of anticoagulation clinics is an urgent need for the Mexican health system., (Copyright: © 2021 Permanyer.)

Background: Hyper-CVAD is the treatment for patients with acute lymphoblastic leukemia in our institution., Objective: To evaluate the impact of single nucleotide polymorphisms at genes associated with methotrexate metabolism on survival., Methods: The presence of the single nucleotide polymorphisms G80A at reduced folate carrier-1 gene and C677T in the methylenetetrahydrofolate reductase gene was determined by denaturing high performance liquid chromatography and validated by sequencing. Both single nucleotide polymorphisms were evaluated in 71 healthy donors and in an exploratory pilot trial with acute lymphoblastic leukemia patients to determine the influence of these single nucleotide polymorphisms on clinical outcome. Clinical characteristics, response, and outcome were registered. A Cox regression analysis was done to evaluate factors influencing response and overall survival., Results: There were no differences in the frequency of single nucleotide polymorphisms between volunteers and acute lymphoblastic leukemia patients according to the Hardy-Weinberg test. Sensitivity and specificity were 72 and 91% for the G80A, and 64 and 75% for the C677T, respectively. The multivariate analysis showed that the T-immunophenotype and the presence of single nucleotide polymorphism G80A reduced folate carrier-1 were associated with a shorter relapse-free survival and overall survival., Conclusions: The presence of G80A single nucleotide polymorphism at reduced folate carrier-1 gene in acute lymphoblastic leukemia patients was associated with a poorer prognosis.

Background: To identify inherited factors: Protein C (PC), protein S (PS), antithrombin (AT), plasminogen (Plg), the activated PC resistance (APCR), prothrombin (PT) mutation G20210 A (PTG20210 A) and methylenetetrahydrofolate reductase C677 T polymorphism (MTHFR C677 T), as well as acquired-risk factors such as: diabetes mellitus, surgeries, smoking, obesity, hypertension, trauma, alcoholism, family history; and their association, in Mexican patients with diagnostic of thrombophilia., Methods: Overall, 200 patients diagnosed with thrombophilia and 100 healthy controls. Commercial kits were used for the coagulometric tests and polymerase chain reaction, restriction fragment length polymorphism for molecular alterations., Results: Alterations were found with an estimated prevalence to PC 0.65%, AT 2.04% and Plg 2.5%, APCR 2%, PT 20210 2%, and MTHFR 65%. The C677 T polymorphism of the MTHFR did not associate with acquired-risk factors so we can suppose that it is an independent risk factor. For the patients that only presented acquired-risk factors (21 of 200), the association smoking-alcoholism showed to be the cause of thrombosis with high risk. The following were also associated: smoking with AT, PC, and alcoholism; obesity with Plg; smoking with alcoholism, and PS deficiency., Conclusions: Risk factors for both primary and secondary and their association were present as a cause of thrombosis in the patients studied, and the possibility to suffer a recurrent thrombosis., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The objective of this study was to evaluate in native cattle the use of an in vitro derived attenuated live vaccine (Babesia bovis-Babesia bigemina). Three commercial farms located in a tropical region in Chiapas State, Mexico were included. For each ranch, 40 animals were selected as negative to Babesia spp. by using an immunofluorescent antibody test (IFAT) and PCR. Animals were distributed in four groups with 10 animals each: (i) <9 months, (ii) 9-18, (iii) 18-36 and (iv) >36 months old. From each group, two subgroups were formed with five animals each; one subgroup was vaccinated and the other served as control without vaccination. Monitoring and sampling were carried out initially at vaccination (day 0), at day 7 and then every 4 weeks for 12 months. During the study rectal temperature ( degrees C), packed cell volume (Ht %) and percentage of erythrocytes parasitized were registered, furthermore IFAT and PCR were performed. Prevalence rate at the beginning of the study was 83% by IFAT. During the survey, 26 non-vaccinated of the 120 selected animals (43%) showed clinical symptoms of babesiosis, confirmed by stained smears versus only four (6.6%) of the vaccinated ones. All Babesia-affected animals required specific treatment. Vaccinated cattle showed titres of up to 1 : 1840 and 1 : 1027 for B. bovis and B. bigemina, respectively by IFAT. Protection conferred by vaccination was about 93%. We propose that this vaccine should not only be used in cattle coming from babesiosis free zones, but also in native cattle kept in hyperendemic areas.

Background and Purpose: Previous studies have demonstrated that a common polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase (MTHFR) is associated with an increased risk for stroke. However, this relation remains controversial. Our aim was to investigate the possible association between the C677T polymorphism in the MTHFR gene and idiopathic ischemic stroke in the young Mexican-Mestizo population., Methods: One hundred seventy-eight patients <45 years with idiopathic ischemic stroke and 183 controls were tested for the C677T polymorphism in the MTHFR gene. Causes of primary thrombophilia as well as classical risk factors for atherothrombotic disease were also evaluated., Results: There was a significant difference in the genotype distribution between patients and controls (p = 0.01), but the allele frequency was similar in both groups (p = 0.09). The univariate analysis identified the T allele as a risk factor for ischemic stroke (TT and CT carriers), as compared with homozygous for C allele (p = 0.01). Hypertension and smoking prevalences were significantly higher in the group of patients. Also the T allele was significantly associated with large-vessel ischemic stroke. The postoral methionine load homocysteine levels were higher in patients with ischemic stroke versus controls (p < 0.001). There was a low prevalence of primary thrombophilia markers., Conclusions: The T allele from the C677T polymorphism of the MTHFR gene represents an independent risk factor for idiopathic ischemic stroke at young age in the Mexican-Mestizo population. Also, hypertension and smoking were independent risk factors in our study population. Primary thrombophilic risk factors were not associated with ischemic stroke in our population., (Copyright 2010 S. Karger AG, Basel.)

A common cause of hereditary thrombophilia is activated protein C resistance (APCR), and most cases result from factor V Leiden mutation. An APCR phenotype without association with factor V Leiden has been described. This transversal, observational, nonrandomized study evaluated these 2 phenomena in healthy indigenous and mestizo Mexican subjects (n = 4345), including 600 Mexican natives. No indigenous subjects had APCR, but 82 mestizo subjects did. After retesting, 50 subjects had a negative test. The remaining 32 subjects had factor V Leiden, giving a 0.85% prevalence of factor V Leiden in the mestizo Mexican population. Only 31% of APCR carriers had factor V Leiden. These results show a very low prevalence of APCR and factor V Leiden in Mexico. Except for factor V Leiden, there are no other mutations in the factor V gene responsible for the APCR phenotype. Acquired APCR is nearly twice as prevalent as the inherited variant.

Background: Atherothrombotic disease is the leading cause of death worldwide. Most casualties are due to acute myocardial infarction (AMI). Patients younger than 45 years account for 5-10% of AMI cases. These patients generally do not display typical atherothrombotic risk factors., Methods: Our cross-sectional study included adult patients under 45; men and women with AMI were included. A control group of healthy individuals matched for age, sex, and blood group was included to determine the role of several atherothrombotic risk factors on AMI. One hundred and sixty patients were included, the control group was comprised by 77 males (m) and 83 females (f), Results: Our results indicate that 25% of patients (23 m and 18 f) had increased FVIII compared with 8.8% of control subjects. Mean FVIII activity for patients and controls was 134 mg/dl (95%CI=114) vs. 118 mg/dl (95%CI=128-140), respectively (p=0.001). Prevalence of elevated FVIII was higher than the one found for hypertension or diabetes mellitus. HDL cholesterol was higher among patients than controls. Quantitative variables associated with AMI were high FVIII activity, blood monocyte count and HDL cholesterol., Conclusions: Classical atherothrombotic risk factors do not fully explain AMI events in the young. High levels of FVIII activity is a moderate but common risk factor in young people suffering AMI.

Autologous peripheral blood stem cell transplantation is the therapy of choice for the treatment of multiple myeloma (MM) patients younger than 70 years old. Between August 1993 and November 2004, 54 patients with MM were autografted after conditioning with high-dose oral melphalan 140 mg/m(2) in combination with etoposide and carmustine (28 patients) or with high-dose melphalan 200 mg/m(2) I.V. (26 patients). The oral and IV melphalan groups were comparable. There were no significant differences in disease-free survival (DFS) and overall survival (OS) between the groups; however, in patients transplanted in remission, OS and DFS were better in the I.V. melphalan group. Four good-prognostic factors were identified: interval between diagnosis and transplant <18 months, number of prior chemotherapy lines < or =2, remission status (complete or partial), and the use of I.V. melphalan. In conclusion, I.V. melphalan is the therapy of choice for conditioning patients with MM who are in remission.

We studied the effectiveness of a fludarabine/cyclophosphamide-based conditioning regimen without anti-thymocyte globulin in 23 aplastic anemia patients who had no response to previous conventional pharmacologic treatment. Patients received oral busulphan 4 mg/kg/day/2 days, IV cyclophosphamide 350 mg/m(2)/day/3 days, and fludarabine 30 mg/m(2)/day/3 days. For GVHD prophylaxis, patients received MTX 5 mg/m(2) days +1, +3, +6, and +11 and oral cyclosporin A (CyA) 5 mg/kg/day, starting on day -1. Peripheral blood stem cell products were used with a median dose of 5.5 x 10(6) CD34(+)/kg. The patients were followed for an average of 25 months. By a median of day +11, an ANC > 0.5 x 10(9)/L was reached; and by day +12, the platelet count had reached >20,000 x 10(9)/L. Acute grade I-II GVHD occurred in 4 patients, whereas limited chronic GVHD presented in 6 cases. Twenty-one patients (91.3%) achieved engraftment. Two patients failed to engraft, and 4 developed late rejection; 2 of these individuals died, 2 have survived with high transfusion requirements, whereas 2 received a second peripheral blood stem cell infusion and achieved sustained engraftment. Currently 21 (91%) of the 23 patients are alive, whereas 19 of 21 (90%) remain in complete remission. The average cost was about USD 15,000 for this kind of reduced-intensity allotransplant. Reduced-intensity stem cell transplantation represents an affordable alternative to traditional more cytotoxic conditioning for severe aplastic anemia (SAA) patients. Long-term effects however, remain to be evaluated.

Multiple myeloma (MM) is the second most common hematologic malignancy, affecting approximately 14,000 new patients per year in the United States. For over four decades, the standard treatment for MM has been a regimen of melphalan combined with prednisone. Using this treatment modality, complete responses are rare, and 50% of patients have had disease that was resistant to chemotherapy. Attempts have been made to improve the outcome of MM by administering combinations of i.v. poli-chemotherapy, but these treatments are equivalent in terms of overall survival. High-dose therapy with peripheral blood stem cell support can be applied safely in these patients and achieves significantly higher complete remission rates as well as better event-free survival and overall survival. However, neither tumor-cell purging, positive selection, intensification of conditioning with additional chemotherapeutic agents, nor total body irradiation have been shown to improve outcome. The role of tandem transplantation with high-dose melphalan seems to be a good selection of treatment in hospitals having all resources. Future research will include the combination of the best remission-induction regimen with tandem transplants and maintenance treatments (thalidomide, idiotype or dendritic cell vaccination) that will sustain complete remission. Development of non-myeloablative allogeneic transplantation in order to exploit the graft-versus myeloma effect provides an alternative for patients who have a compatible donor. Combining all of these modalities with the new drugs developed few years ago (thalidomide, bortezomib, revlimid), we hope that MM will become a manageable chronic disease and perhaps a curable disease at least for 30% to 40% of the patients.

Introduction: Chronic myeloid leukemia (CML) is characterized by a chromosomal translocation t(9; 22) resulting in the chimeric ber-abl oncogene that encode for the p210 protein which has an increased tyrosine kinase activity. The fusion part of this protein contains a novel aminoacid sequence. If peptides derived from this leukemia-specific part of p210 are expressed in the context of HLA molecules on malignant cells this may elicit immunologically specific responses. Recent studies using synthetic peptides identical to the bcr-abl fusion region revealed that breakpoint specific peptides are capable of binding to the class I molecules HLA-A3, -A11 and -B8. It has been shown that individuals expressing HLA-A3 or HLA-B8 have a diminished risk for development of CML in Caucasoid populations. Other authors have reported a statistically significant increase in the frequency of Cw3 and Cw4 antigens in Causcasoids and European CML patients. These data suggested that Cw3 and Cw4 may be markers for CML susceptibility on these populations., Objective: To asses a possible susceptibility effect of these HLA molecules we studied 63 CML Mexican Mestizo patients and 746 healthy subjects for the distribution of HLA class I and class II molecules., Results: The gene products that showed statistically significant differences between CML patients and controls were DR14, DR3, Cw3 and Cw4. DR14 and DR3 were significantly increased in the patients group with respect to the controls group (DR14 antigen frequency: 3.17% vs. 0.29%; p = 0.03; DR3 20.63% vs. 8.33%; p = 0.0001). Cw3 and Cw4 were significantly decreased in the patient group (Cw3 26.9% vs. 49.11%; p = 0.03; Cw4 antigen frequency 23.8% vs. 86.28%; p = 0.0000001). The relative risk for DR14 was 10.48 (95% CI 1.52-79.29) and for DR3 was 3.96 (95% CI 2.05-7.71). The relative risk for Cw3 was 0.38 (95% CI 0.08-1.79) and for Cw4 was 0.11 (95% CI 0.048-0.81)., Conclusion: These results suggest that the development of CML is apparently associated with HLA phenotypes specific to each population, and indicate that Cw3 and Cw4 expression may result in a protective effect on the CML acquisition on Mexican Mestizo population probably by bcr-abl breakpoint peptides presentation through these HLA molecules.

Background: Bone marrow transplantation (BMT) is the therapy of choice for patients with chronic myeloid leukemia (CML) who have a human leukocyte antigen (HLA)-identical donor and are under 50 years of age., Methods: Here, 45 patients with CML were treated with busulfan (Bu) 16 mg/kg and cyclophosphamide (Cy) 120 mg/kg before allogeneic BMT from an HLA-identical sibling 27 (60%) or a 1-antigen mismatch donor 18 (40%). Eighteen patients (40%) were in the early chronic phase (CP) and 27 (60%) in late CP. We used cyclosporin-A (CsA) in 20 patients and cyclosporin-A-methotrexate (CsA-MTX) in 25 for graft-vs.-host disease (GVHD) prophylaxis., Results: We observed a high incidence of acute and chronic GVHD (69% and 67%, respectively). A multivariate analysis identified differences in the sex of the donor and the recipient (p = 0.03) and grade III-IV acute GVHD (p = 0.0001) as significant adverse influences on disease-free survival. Age, sex, chronic GVHD, disease phase, one antigen-mismatch and use of CsA or CsA-MTX had no statistical significance. The 3-year probabilities of relapse, disease-free survival, and overall survival were 11%, 55%, and 60%, respectively. Transplant-related mortality occurred in 31% of the cases. The high frequency of GVHD is explained by HLA determination by serological typing, differences in sex between the donor and recipient, and a high proportion (40%) of 1 antigen-mismatch donors., Conclusions: BMT is a procedure feasible for patients with CML in early and late chronic phase and even in those with an HLA non-identical donor. Strategies directed to decrease acute GVHD could improve the outcome of these patients.

Background: The use of conventional cyclosporine (Sandimmune) requires great care, as this drug exhibits a narrow therapeutic index and wide interindividual variability in its pharmacokinetics. Recently, a new microemulsion formulation (Neoral) was developed. With this formulation, cyclosporine is absorbed at the small intestine without the presence of bile. Therefore, the objective of this study was to compare the bioavailability of cyclosporine after the administration of conventional and microemulsion formulations in healthy Mexican volunteers in order to approach the optimal dosage regimen of microemulsion in the Mexican population., Methods: The trial was conducted using 23 healthy volunteers according to a randomized crossover design. Volunteers received one 7.5-mg/kg dose as each formulation, with a 1-week washout period between treatments. Blood samples of 0.5 mL were obtained according to the following schedule: 0, 0.5, 1, 2, 3, 4, 5, 6, 8, 12, and 24 h after medication., Results: These indicated that Cmax and AUC0-24 values were higher with the microemulsion than with the conventional formulation., Conclusions: The microemulsion had a better absorption profile than the conventional formulation, because plasma levels with the conventional formulation demonstrated oscillations rather than reflecting an erratic absorption. Lower doses of the microemulsion are required to obtain Cmax values similar to those obtained with conventional cyclosporine.