Inexpensive metagenomic DNA extraction protocol with high quality from marine sediments contaminated by petroleum hydrocarbons.

Marine environments are a reservoir of relevant information on dangerous contaminants such as hydrocarbons, as well as microbial communities with probable degradation skills. However, to access microbial diversity, it is necessary to obtain high-quality DNA. An inexpensive, reliable, and effective metagenomic DNA (mgDNA) extraction protocol from marine sediments contaminated with petroleum hydrocarbons was established in this study from modifications to Zhou's protocol. The optimization included pretreatment of sediment with saline solutions for the removal of contaminants, a second precipitation and enzymatic degradation of RNA, followed by purification of mgDNA extracted by electroelution. The results obtained indicated that the modifications applied to 12 sediments with total petroleum hydrocarbon (TPH) concentrations from 22.6-174.3 (µg/g dry sediment) yielded 20.3-321.3 ng/µL mgDNA with A260/A280 and A260/A230 ratios of 1.75 ± 0.08 and 1.19 ± 0.22, respectively. The 16S rRNA amplification confirmed the purity of the mgDNA. The suitability of this mgDNA extraction protocol lies in the fact that all chemical solutions utilized are common in all molecular biology laboratories, and the use of dialysis membrane does not require any sophisticated or expensive equipment, only an electrophoretic chamber.

Elimination of large uremic toxins by a dialyzer specifically designed for high-volume convective therapies.

BACKGROUND: Unlike conventional hemodialysis treatments, which rely almost solely on diffusion-related mechanisms for solute removal, hemodiafiltration (HDF) allows more efficient removal of higher molecular weight toxins due to convective transport mechanisms. To facilitate the removal of these toxins in HDF treatment modalities, dialyzers with highly efficient high-flux membranes are necessary. This study assessed the large uremic toxin removal ability of a high-flux dialyzer (FX CorDiax 60) specifically designed to facilitate convective therapies compared with a standard high-flux dialyzer (FX 60). METHODS: In an open, randomized, cross-over, single-center, controlled, prospective clinical study, 30 adult chronic hemodialysis patients were treated by post-dilution online HDF with the FX 60 or the FX CorDiax 60 dialyzer. All other dialysis parameters were kept constant in both study arms. The reduction rate (RR) of blood urea nitrogen, phosphate, ß2-microglobulin (ß2-m), myoglobin, prolactin, α1-microglobulin, α1-acid glycoprotein, albumin and total protein as well as the elimination into dialysate was intraindividually compared for the two dialyzer types. RESULTS: For FX CorDiax 60 versus FX 60, the RR was significantly higher for blood urea nitrogen (86.23 ± 4.14 vs. 84.89 ± 4.59%, p = 0.015), ß2-m (84.67 ± 3.79 vs. 81.30 ± 4.82%, p < 0.0001), myoglobin (75.23 ± 10.48 vs. 58.60 ± 12.1%, p < 0.0001), prolactin (72.96 ± 9.68 vs. 56.91 ± 13.01%, p < 0.0001) and α1-microglobulin (20.89 ± 18.27 vs. 13.60 ± 12.50%, p = 0.016). There were no significant differences in the RR for phosphate, α1-acid glycoprotein, albumin and total protein. Mass removal was significantly higher with the FX CorDiax 60 than with the FX 60 for ß2-m (0.26 ± 0.09 vs. 0.24 ± 0.09 g, p = 0.0006), myoglobin (1.83 ± 0.89 vs. 1.51 ± 0.76 mg, p = 0.0017), prolactin (0.17 ± 0.13 vs. 0.14 ± 0.08 mg, p = 0.02) and albumin (4.25 ± 3.49 vs. 3.01 ± 2.37 g, p = 0.03). CONCLUSIONS: This study demonstrates that treating patients with an FX CorDiax 60 instead of an FX 60 dialyzer in post-dilution HDF mode significantly increases the elimination of middle molecules.

Effect of imiquimod as compared with surgery on the cancerization field in basal cell carcinoma.

BACKGROUND: Patients with basal cell carcinoma (BCC) have an increased risk of subsequent BCCs. It is possible that imiquimod might reduce this risk by acting on the cancerization field. OBJECTIVE: To examine the ability of imiquimod to reduce subsequent BCCs. METHODS: Retrospective cohort study of patients with BCC treated at our hospital between 2003 and 2011. The patients were divided into 2 groups depending on whether they had been treated with surgery or with imiquimod. Comparing the 2 groups, we analyzed the development of new BCCs, the time that elapsed between first and subsequent tumors, and the site of occurrence of the second BCC with respect to the first one (local, same lymphatic drainage basin or anatomic region, or other). Survival methods were used to analyze the data. RESULTS: We reviewed the charts of 623 patients. Of these, 550 had been treated with surgery (88.3%) and 71 with imiquimod (11.4%). Overall, a second BCC occurred in 36.4% of patients (n=227). The rate of occurrence was 38.2% in the surgery group and 23.9% in the imiquimod group (P=.02). The hazard ratio for the occurrence of a subsequent BCC was 2.13 (95% CI, 1.28-3.53) for patients treated with surgery compared with those treated with imiquimod. Imiquimod reduced the risk of a second BCC locally, regionally, and in the lymphatic drainage area. Our findings are limited by the retrospective nature of our study and the small number of patients treated with imiquimod. CONCLUSIONS: Imiquimod may reduce the risk of subsequent BCC in patients treated for BCC and its effect could last for up to 2 years in local, regional and lymphatic cancerization fields. We believe that the cancerization field concept should be expanded to include not only the local area, but also the pertinent anatomic region and the regional lymphatic drainage area.

Simple and inexpensive DNA extraction protocol for studying the bacterial composition of sludges used in microbial fuel cells.

Bacteria oxidize organic matter and nutrients to produce electric energy in microbial fuel cells (MFC) - a technology of increasing importance because of its sustainability. To improve the performance of MFCs, it is necessary not only to gain a better understanding of MFC engineering designs, but also to improve the understanding of the composition of the microbial communities in MFCs. Fast and efficient DNA extraction protocols that are suitable for extracting diverse bacterial genomes are necessary to identify the bacterial diversity present in MFCs and to further monitor the dynamic changes of microbial communities. This study focused on testing different direct cell lysis protocols to extract DNA from a microbial sludge harvested from an MFC. The protocol that achieved the best results was based on a previous study, but was modified by eliminating a chaotropic salt and the special columns used for nucleic acid purification. The efficiency of this less expensive and more straightforward protocol was confirmed by PCR amplification of the 16S rRNA gene and denaturing gradient gel electrophoresis analysis, which confirmed the extraction of multiple genomes. The sequences of 10 clones revealed the presence of phyla, Proteobacteria, Firmicutes and Actinobacteria, comprising both Gram-negative and Gram-positive bacteria. Some of these bacteria were identified at the genus level, e.g., Clostridium, Pseudoxanthomonas, Tistrella, and Enterobacter; these genera have been described in active sludges from wastewater treatment, supporting the congruency of our results. Therefore, this protocol is a useful tool for analysis of the bacteria responsible for energy production in MFCs.

[Effectiveness of primary care physicians and dermatologists in the diagnosis of skin cancer: a comparative study in the same geographic area]. / Estudio comparativo de la habilidad en el diagnóstico clínico del cáncer cutáneo entre el médico de familia y el dermatólogo en una misma área geográfica.

BACKGROUND: skin cancer is the most common malignant tumor in white individuals. Early diagnosis and treatment are key factors in reducing morbidity. We performed a prospective observational study throughout 2008 to assess the ability of primary care physicians to diagnose nonmelanoma skin cancer. METHODS: the study was undertaken in a single geographic area corresponding to the region served by a primary health care center. Patients who were referred to a dermatologist were included if the primary care physician indicated skin cancer in the differential diagnosis on the referral form. Patients were also included if the dermatologist suspected skin cancer even if the referral from primary care had not indicated it. RESULTS: primary care physicians had a sensitivity of 0.45 and a specificity of 0.16 for the diagnosis of skin cancer, whereas dermatologists had a sensitivity of 0.97 and a specificity of 0.75. The α statistic as a measure of agreement was -0.56. CONCLUSIONS: The ability of primary care physicians to diagnose skin cancer was appreciably lower than that of dermatologists. This may result in substantial delays in the provision of appropriate care for patients with skin cancer considering the role played by primary care physicians in screening for the disease in the Spanish national health system.

First Report of Orange Rust of Sugarcane Caused by Puccinia kuehnii in Mexico, El Salvador, and Panama.

Symptoms of sugarcane orange rust were observed on July 17, 2008 on sugarcane cvs. Mex 57-1285, Mex 61-230, and Co 301 (a clone received in Mexico in 1953) at the Centro de Investigación y Desarrollo de la Caña de Azúcar en Tuxtla Chico, Chiapas, Mexico. In El Salvador, from August 2008 through January 2009, rust symptoms were observed on cv. CP 72-2086 (previously resistant to brown rust caused by Puccinia melanocephala Syd. & P. Syd.) in 117 dispersed sugarcane-production fields in various localities of El Salvador. Likewise, rust symptoms were first observed on sugarcane cv. SP 74-8355 (more than 25% severity and considered resistant to brown rust) at Natá, Coclé Province in Panama from January to February 2008. Dried herbarium leaf samples of sugarcane rust-infected leaves collected in El Salvador and Mexico were sent to the ARS, USDA Systematic Mycology and Microbiology Laboratory in Beltsville MD for identification. Panamanian samples were collected similarly and analyzed at the CALESA Biotechnology Laboratory. Morphological features of uredinial lesions and urediniospores were distinct from those of P. melanocephala and consistent with P. kuehnii E. J. Butler observed previously on specimens from Florida, Guatemala, Costa Rica, and Nicaragua (1-3). Analysis of the ITS1, 5.8S, and ITS2 and 28S large subunit rDNA sequences of the rust on infected cvs. Mex 57-1285, Mex 61-230, and Co 301 (BPI 878930, 879139, and 879140; GenBank Accession Nos. GO283006, GO283004, and GO283005, respectively) from Mexico and cv. CP 72-2086 from three locations in El Salvador (BPI 879135, 879136, and 879137; GenBank Accession Nos. GO283009, GO283007, and GO283008, respectively) all confirmed the identification of P. kuehnii. Similar analysis of the ITS1, 5.8S, and ITS2 rDNA sequence for the rust infecting cv. SP 74-8355 (GenBank Accession No. GO281584) confirmed the identification of P. kuehnii in Panama. To our knowledge, this is the first report of P. kuehnii causing orange rust disease of sugarcane in El Salvador, Mexico, and Panama. These findings also confirm the wider distribution of orange rust in the Western Hemisphere. References: (1) E. Chavarria et al. Plant Dis. 93:425, 2009. (2) J. C. Comstock et al. Plant Dis. 92:175, 2008. (3) W. Ovalle et al. Plant Dis. 92:973, 2008.

Thioredoxin and glutaredoxin regulate metabolism through different multiplex thiol switches.

The aim of the present study was to define the role of Trx and Grx on metabolic thiol redox regulation and identify their protein and metabolite targets. The hepatocarcinoma-derived HepG2 cell line under both normal and oxidative/nitrosative conditions by overexpression of NO synthase (NOS3) was used as experimental model. Grx1 or Trx1 silencing caused conspicuous changes in the redox proteome reflected by significant changes in the reduced/oxidized ratios of specific Cys's including several glycolytic enzymes. Cys91 of peroxiredoxin-6 (PRDX6) and Cys153 of phosphoglycerate mutase-1 (PGAM1), that are known to be involved in progression of tumor growth, are reported here for the first time as specific targets of Grx1. A group of proteins increased their CysRED/CysOX ratio upon Trx1 and/or Grx1 silencing, including caspase-3 Cys163, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) Cys247 and triose-phosphate isomerase (TPI) Cys255 likely by enhancement of NOS3 auto-oxidation. The activities of several glycolytic enzymes were also significantly affected. Glycolysis metabolic flux increased upon Trx1 silencing, whereas silencing of Grx1 had the opposite effect. Diversion of metabolic fluxes toward synthesis of fatty acids and phospholipids was observed in siRNA-Grx1 treated cells, while siRNA-Trx1 treated cells showed elevated levels of various sphingomyelins and ceramides and signs of increased protein degradation. Glutathione synthesis was stimulated by both treatments. These data indicate that Trx and Grx have both, common and specific protein Cys redox targets and that down regulation of either redoxin has markedly different metabolic outcomes. They reflect the delicate sensitivity of redox equilibrium to changes in any of the elements involved and the difficulty of forecasting metabolic responses to redox environmental changes.

[Anemia of chronic kidney disease: Protocol of study, management and referral to Nephrology]. / Anemia en la enfermedad renal crónica: protocolo de estudio, manejo y derivación a Nefrología.

The objective of this protocol is to know which test are needed to study an anaemia in a patient with chronic kidney disease, the differential diagnosis of renal anaemia, to know and correct other deficiency anaemias, and the criteria for referral to Nephrology or other specialties of the anaemic patient with chronic kidney disease.

Integration of human papillomavirus type 6a DNA in a tonsillar carcinoma: chromosomal localization and nucleotide sequence of the genomic target region.

Human papillomavirus type 6a (HPV 6a) DNA was detected in a tonsillar carcinoma both as integrated and episomal molecules, and one viral-cellular junction was molecularly cloned (Bercovich et al., J. Gen Virol., 72: 2569-2572, 1991). The cellular sequence was used as a probe for the isolation of a cosmid from a normal human genomic DNA library. A 2.7-kilobase subclone including the integration site was sequenced. It was shown to contain sequences with similarities to the E2 and L2 regions of human papillomaviruses, a 5' truncated long interspersed repeated DNA element type 1 retrotransposon, and a fragment of an O-repeat element. The chromosomal localization of the integration site was determined to be at region 24 of the long arm of chromosome 10 (10q24). This is the region where the fragile site is located in which HPV 18 DNA is integrated in the cell line FEP18-5. In addition it contains the site of breakpoints affecting protooncogenes Hox11 and Lyt10. Other genes related to cell division and DNA repair have also been mapped to this chromosomal band. Analysis of genomic DNA of cell lines and patients using 10q24-derived probes is presented. The integration of human papillomavirus type 6 DNA into chromosome 10q24 may have disrupted a cellular gene critical for normal cell growth, which further analysis should help to identify.

Brachial neuritis or Parsonage-Turner syndrome: A problem of liability. A presentation of 3 cases. / Neuritis braquial o síndrome de Parsonage-Turner: un problema de responsabilidad. A propósito de 3 casos.

Neuralgic amyotrophy, brachial neuritis or Parsonage-Turner syndrome is a rare neuromuscular involvement of unknown aetiology. When it onsets in connection with a health care act, such as childbirth or surgery, a malpractice argument is often used as a cause of adverse outcome, usually due to an incorrect position of the patient on the operating table, a circumstance which directly involves the anesthesia area. Three cases are presented of Parsonage-Turner syndrome following very different surgery, with different results as regards prognosis. A review and discussion of bibliography is presented on the possibility that such circumstances are the subject of malpractice claims. Special emphasis is placed on the most currently accepted aetiopathogenic theories, and the relationship of this syndrome with the surgical act as a determining medico-legal aspect. Valuation parameters are proposed.

Clinical experience with the use of cyclosporin A in psoriasis. Results of a retrospective study.

The efficacy of cyclosporin A (Sandimmun Neoral) in severe psoriasis was analysed in 70 patients included in a retrospective descriptive study conducted at our Dermatology Department from January 1994 until December 2000. After 8 weeks of treatment, with an initial dose of 2.5-3 mg/kg/day, the reduction in the Psoriasis Area and Severity Index (PASI) score was>75% in 61% of patients. Most of the side effects observed turned out to be susceptible to being reversed over time or by dose reduction. The results of this study show that continuous and low-dose cyclosporin therapy is a safe and efficacious treatment for severe chronic psoriasis.

[DNA identification of human papillomavirus in anogenital condyloma of a male population]. / Identificación de DNA de papilomavirus humano en condilomas anogenitales de una población masculina.

Human Papillomaviruses (HPV) are the cause of benign human anogenital lesions where HPV 6 and HPV 11 are most commonly found. Conversely, HPV 16, 18, 31 and 33 are frequently detected in genital carcinomas and are thus considered as oncogenic types. In order to analyze the prevalence of specific HPV types in an Argentine male population, 43 anogenital lesions from different patients with diagnosis of condyloma acuminata were analyzed. These lesions were localized in different regions of the male genitalia comprising the corona glandis, urethral meatus, skin of the penis, scrotum and anus. The biopsies were screened for the presence of HPV 6, 11, 16, 18, 30, 31 and 33 by Southern blot at different stringent conditions of hybridization (Tm -48 degrees C and Tm -20 degrees C). HPV DNA was found in 41 examined cases (95.3%) with a clear prevalence of HPV 6 and HPV 11 types (51.2% and 23.3% respectively). Six samples (14.0%) were positive only under nonstringent conditions of hybridization. Mixed infections between HPV 16, 18, 30, 31, 33 or a HPV 30 related type with HPV 6 or HPV 11 were detected in 8 specimens (18.6%). Only one case was between HPV 16 and HPV 30. Two additional samples were only positive for HPV 30. Experiments in progress about the prevalence of HPV types in female lesions as well as in normal subjects will contribute to complete the description of the epidemiology of these infections in Argentina.

[Anesthesia for the surgery of delayed postoperative stenosis in the pulmonary suture in children with corrected transposition of the great vessels with Jatene's technique]. / Anestesia para la cirugía de la estenosis postoperatoria tardía en la sutura pulmonar, de niños corregidos de la D-transposición de grandes arterias mediante la técnica de Jatene.

Any patient with congenital heart disease is at high risk for anesthesia no matter what surgical procedure is performed. Children undergoing D-transposition of the great arteries using Jatene's technique present stenosis of the pulmonary artery in 10-20% of cases and may require surgery to correct that or some other surgically caused anomally. In either case the children must be managed as patients with heart disease, with special attention to cardiovascular depression and rhythm abnormalities. We report the cases of two children who underwent D-transposition of the great arteries in the neonatal period using Jatene's anatomical technique. They were later anesthetized at ages 5 and 6 years to correct pulmonary suture stenosis. Recovery was good.

[Analysis of preoperative reserve criteria and intraoperative transfusion of blood derivatives at an anesthesiology and recovery service]. / Análisis de los criterios de reserva preoperatoria y transfusión intraoperatoria de derivados sanguíneos en un servicio de anestesiología y reanimación.

Three hundred and three patients undergoing elective surgery were studied prospectively. Patient data and results of serial blood cell counts were recorded before and after surgery and used to evaluate the criteria used to reserve and transfuse blood and blood products, as well as to assess the outcome of transfusions performed. Six hundred and ninety-nine units were reserved, indicating a reservation-to-transfusion ratio of 1.8. The most often cited reasons for reserving blood were surgical technique, nature of disease and prolonged surgery. A high number of reservations were called for from the ward by the surgeons themselves. A total of 180 patients were given transfusions, the main reason being the anesthesiologist's judgement that the Hb count was low (in 26% of cases). Transfusions because of slight bleeding during surgery and prolonged surgery gave rise to the highest Hb counts. The lowest post-transfusion Hb counts recorded occurred when the reason cited was presence of signs of anemia. We conclude that the ratio of reservations to transfusions in our study was acceptable, as were the reasons justifying reserves. There is an overall tendency to achieve excessively high Hb counts (10-11 g/dl) in the early postoperative period. The best criterion for performing transfusion is the presence of signs of anemia.

Comprehensive care program for elderly patients over 65 years with hip fracture.

OBJECTIVES: To report the health outcomes of a multidisciplinary care program for patients over 65 years with hip fracture. PATIENTS AND METHODS: We have developed a care coordination model for the comprehensive care of hip fracture patients. It establishes what, who, when, how and where orthopedists, internists, family physicians, emergency, intensive care, physiotherapists, anesthetists, nurses and workers social intervene. All elderly patients over 65 years admitted with the diagnosis of hip fracture (years 2006 to 2010) were retrospectively evaluated. RESULTS: One thousand episodes of hip fracture, corresponding to 956 patients, were included. Mean age was 82 years and mean stay 6.7 days. This was reduced by 1.14 days during the 5 years of the program. A total of 85.1% were operated on before 72 yours, and 91.2% during the program. Incidence of surgical site infection was 1.5%. In-hospital mortality was 4.5%, (24.2% at 12 months). Readmissions at one years was 14.9%. Independence for basic activity of daily living was achieved by 40% of the patients. CONCLUSIONS: This multidisciplinary care program for hip fracture patients is associated with positive health outcomes, with a high percentage of patients treated early (more than 90%), reduced mean stay (less than 7 days), incidence of surgical site infections, readmissions and inpatient mortality and at one year, as well as adequate functional recovery.

Anemia en la enfermedad renal crónica: protocolo de estudio, manejo y derivación a Nefrología / Anemia of chronic kidney disease: protocol of study, management and referral to Nephrology

El objetivo del protocolo es conocer qué estudios deben solicitarse ante una anemia en un paciente con enfermedad renal crónica, el diagnóstico diferencial de la anemia renal, conocer y corregir otras anemias carenciales y los criterios de remisión del paciente anémico con enfermedad renal crónica a Nefrología u otras especialidades (AU)

The objective of this protocol is to know which test are needed to study an anaemia in a patient with chronic kidney disease, the differential diagnosis of renal anaemia, to know and correct other deficiency anaemias, and the criteria for referral to Nephrology or other specialties of the anaemic patient with chronic kidney disease (AU)

[State of acute phase markers and oxidative stress in patients with kidney stones in the urinary tract]. / Estado de los marcadores de fase aguda y estrés oxidativo en los enfermos con litiasis de la vía urinaria.

OBJECTIVE: This present study has aimed to assess the state of acute phase markers and oxidative stress in patients with kidney stones. MATERIAL AND METHODS: A prospective study was carried out on 100 patients with kidney stones and 25 healthy controls. Albumin, ß2 microglobulin, Gamma-glutamyl transpepsidase, Lactate dehydrogenase, Tumor necrosis factor alpha, Interleukin 1 and Interleukin-6 were evaluated as acute phase markers and lipid peroxidation products, Superoxide dismutase and Glutathione peroxidase levels acted as oxidative stress markers. RESULTS: An increase in renal cell damage markers as expressed by the ß2 microglobulin (p=0.04), albumin (p=0.004), Lactate dehydrogenase (p=0.001) and Gamma glutamyl transpepsidasa (p=0.01) was observed in the patient group. There was a direct correlation between levels of ß2 microglobulin and stone size (r=0.3, p=0.03). The association between stone size and cytokine activation was observed to be stronger in patients with staghorn calculi. In these patients, Tumor necrosis factor alpha (p=0.011), Interleukin 1 (p=0.004) and Interleukin 6 (p=0.004) were significantly higher. Patients with stones in the urinary tract showed data of significantly higher oxidative stress, expressed as an increase in levels of lipid peroxidation products (p=0.03) and a decrease in the antioxidant activity of Superoxide dismutase (p=0.03) and Glutathione peroxidase (p=0.002). CONCLUSIONS: Patients undergoing urolithiasis showed an elevation of acute phase markers, associated with oxidative stress as expressed by an increase in lipid peroxidation products and a decrease in the antioxidant enzyme activity.

Follicular dynamics, corpus luteum growth and regression in multiparous buffalo cows and buffalo heifers / Dinámica folicular, crecimiento y regresión del cuerpo lúteo en búfalas multíparas y novillas

Objective. Characterize the follicular dynamics and luteal growth and regression pattern of multiparous (MB) and heifer (BH) Murrah buffaloes in Colombian tropical conditions. Material and methods. Ten MB and ten BH were synchronized with a progesterone-releasing intravaginal device. No artificial insemination was performed during the estrous and daily ultrasound examinations were performed 15 days later to determine the number and diameter of the structures present in both ovaries in the subsequent natural estrous cycle. The Student's T test was used to evaluate differences between MB and BH. All data are presented as mean ± standard deviation. Results. The length of the estrous cycle was 22.00±4.50 days for MB and 22.00±2.70 days for BH. Follicular growth occurs in one (n=1; 5.89%), two (n=14; 82.35%) or three waves (n=2; 11.76%). The first wave initiated the day after ovulation with the recruitment of 8.33±2.06 and 10.00±2.72 follicles in MB and BH, while the second wave started on day 11.00±2.00 and 10.50±2.82, presenting 8.37±2.26 and 8.00±1.51 follicles. The third wave began on day 16.21±3.10 showing 6.50±1.70 follicles, only BM had three waves. The maximum luteal diameter was 19.58±4.16 mm and 17.74±3.32 mm respectively. There were no significant differences between the groups for these variables. Conclusions. These results show that the follicular development in buffaloes occurs in waves, where two waves is the most common pattern, as previously reported by other authors.

Objetivo. Caracterizar la dinámica folicular y el patrón de crecimiento y regresión del cuerpo lúteo de búfalas multíparas (BM) y búfalas novillas (BN) de la raza Murrah en condiciones del trópico colombiano. Materiales y métodos. Diez BM y diez BN fueron sincronizadas con dispositivo intravaginal de liberación de progesterona. No se realizó la inseminación artificial al momento del celo y 15 días después se inició el seguimiento ultrasonográfico para determinar el número y diámetro de las estructuras presentes en ambos ovarios en el subsecuente ciclo estral natural. Las diferencias entre BM y BN se evaluaron con pruebas T. Los datos se presentan como media ± desviación estándar. Resultados. La duración del ciclo estral fue de 22.00±4.50 y 22.00±2.70 días en BM y BN. El crecimiento folicular ocurrió en una (n=1; 5.89%), dos (n=14; 82.35%) o tres (n=2; 11.76%) ondas. La primera onda inicio el día siguiente a la ovulación con el reclutamiento de 8.33±2.06 y 10.00±2.72 folículos en BM y BN, mientras que la segunda onda inicio el día 11.00±2.00 y 10.50±2.82 con 8.37±2.26 y 8.00±1.51 folículos. La tercera onda inicio el día 16.21±3.10 con 6.50±1.70 folículos, sólo BM presentaron tres ondas. El diámetro máximo luteal fue de 19.58±4.16 mm y 17.74±3.32 mm. No se observaron diferencias significativas entre los grupos para estas variables. Conclusiones. Los resultados muestran que el desarrollo folicular de las búfalas se dio en ondas, siendo dos ondas el patrón más común, similar a lo reportado por otros autores.