Phenotypic characterization, genetic mapping and candidate gene analysis of a source conferring reduced plant height in sunflower.

Reduced height germplasm has the potential to increase stem strength, standability, and also yields potential of the sunflower crop (Helianthus annuus L. var. macrocarpus Ckll.). In this study, we report on the inheritance, mapping, phenotypic and molecular characterization of a reduced plant height trait in inbred lines derived from the source DDR. This trait is controlled by a semidominant allele, Rht1, which maps on linkage group 12 of the sunflower public consensus map. Phenotypic effects of this allele include shorter height and internode length, insensibility to exogenous gibberellin application, normal skotomorphogenetic response, and reduced seed set under self-pollination conditions. This later effect presumably is related to the reduced pollen viability observed in all DDR-derived lines studied. Rht1 completely cosegregated with a haplotype of the HaDella1 gene sequence. This haplotype consists of a point mutation converting a leucine residue in a proline within the conserved DELLA domain. Taken together, the phenotypic, genetic, and molecular results reported here indicate that Rht1 in sunflower likely encodes an altered DELLA protein. If the DELPA motif of the HaDELLA1 sequence in the Rht1-encoded protein determines by itself the observed reduction in height is a matter that remains to be investigated.

Molecular characterization of Als1, an acetohydroxyacid synthase mutation conferring resistance to sulfonylurea herbicides in soybean.

KEY MESSAGE: The AHAS gene family in soybean was characterized. The locus Als1 for sulfonylurea resistance was mapped and the resistant allele was characterized at the molecular level. Sulfonylurea (SU) resistance in soybean is controlled by Als1, a semi-dominant allele obtained by EMS mutagenesis over the cultivar Williams 82. The overall objective of this research was to map Als1 in the soybean genome and to determine the nucleotidic changes conferring resistance to SU. Four nucleotide sequences (GmAhas1-4) showing high homology with the Arabidopsis thaliana acetohydroxyacid synthase (AHAS, EC 4.1.3.18) gene sequence were identified by in silico analysis, PCR-amplified from the SU-resistant line BTK323STS and sequenced. Expression analysis showed that GmAhas1, located on chromosome 4 by in silico analysis, is the most expressed sequence in true leaves. F2:3 families derived from the cross between susceptible and resistant lines were evaluated for SU resistance. Mapping results indicate that the locus als1 is located on chromosome 4. Sequence comparison of GmAhas1 between BTK323STS and Williams 82 showed a single nucleotide change from cytosine to thymine at position 532. This transversion generates an amino acid change from proline to serine at position 197 (A. thaliana nomenclature) of the AHAS catalytic subunit. An allele-specific marker developed for the GmAhas1 mutant sequence cosegregated with SU resistance in the F2 population. Taking together, the mapping, expression and sequencing results indicate that the GmAhas1 sequence corresponds to the Als1 gene sequence controlling SU resistance in soybean. The molecular breeding tools described herein create the basis to speed up the identification of new mutations in soybean AHAS leading to enhanced levels of resistance to SU or to other families of AHAS inhibitor herbicides.

Molecular mapping of a sunflower rust resistance gene from HAR6.

Sunflower rust, caused by Puccinia helianthi Schw., can result in significant yield losses in cultivated sunflower (Helianthus annuus L. var. macrocarpus Ckll.). HAR6 is a germplasm population resistant to most predominant rust races. The objectives of this study were to map the resistance factor present in HAR6 (R HAR6 ), and to provide and validate molecular tools for the identification of this gene for marker assisted selection purposes. Virulence reaction of seedlings for the F2 population and F2:3 families suggested that a single dominant gene confers rust resistance in HAR6-1, a selected rust resistance line from the original population. Genetic mapping with eight markers covered 97.4 cM of genetic distance on linkage group 13 of the sunflower consensus map. A co-dominant marker ZVG61 is the closest marker distal to R HAR6 at a genetic distance of 0.7 cM, while ORS581, a dominant marker linked in the coupling phase, is proximal to R HAR6 at a genetic distance of 1.5 cM. Validation of these markers was assessed by converting a susceptible line into a rust resistant isoline by means of marker assisted backcrossing. The application of these results to assist the breeding process and to design new strategies for rust control in sunflower is discussed.

Inheritance and molecular characterization of broad range tolerance to herbicides targeting acetohydroxyacid synthase in sunflower.

Ahasl1 is a multilallelic locus where all the induced and natural mutations for herbicide tolerance were described thus far in sunflower (Helianthus annuus L.). The allele Ahasl1-1 confers moderate tolerance to imidazolinone (IMI), Ahasl1-2, and Ahasl1-3 provides high levels of tolerance solely to sulfonylurea (SU) and IMI, respectively. An Argentinean wild sunflower population showing plants with high level of tolerance to either an IMI and a SU herbicide was discovered and used to develop an inbred line designated RW-B. The objectives of this work were to determine the relative level and pattern of cross-tolerance to different AHAS-inhibiting herbicides, the mode of inheritance, and the molecular basis of herbicide tolerance in this line. Slight or no symptoms observed after application of different herbicides indicated that RW-B possesses a completely new pattern of tolerance to AHAS-inhibiting herbicides in sunflower. Biomass response to increasing doses of metsulfuron or imazapyr demonstrated a higher level of tolerance in RW-B with respect to Ahasl1-1/Ahasl1-1 and Ahasl1-2/Ahasl1-2 lines. On the basis of genetic analyses and cosegregation test, it was concluded that tolerance to imazapyr in the original population is inherited as a single, partially dominant nuclear gene and that this gene is controlling the tolerance to four different AHAS-inhibiting herbicides. Pseudo-allelism test permitted us to conclude that the tolerant allele present in RW-B is an allelic variant of Ahasl1-1 and was designated as Ahasl1-4. Nucleotide and deduced amino acid sequence indicated that the Ahasl1-4 allele sequence of RW-B has a leucine codon (TTG) at position 574 (relative to the Arabidopsis thaliana AHAS sequence), whereas the enzyme from susceptible lines has a tryptophan residue (TGG) at this position. The utilization of this new allele in the framework of weed control and crop rotation is discussed.

Response to imazapyr and dominance relationships of two imidazolinone-tolerant alleles at the Ahasl1 locus of sunflower.

Imisun and CLPlus are two imidazolinone (IMI) tolerance traits in sunflower (Helianthus annuus L.) determined by the expression of different alleles at the same locus, Ahasl1-1 and Ahasl1-3, respectively. This paper reports the level of tolerance expressed by plants containing both alleles in a homozygous, heterozygous and in a heterozygous stacked state to increasing doses of IMI at the enzyme and whole plant levels. Six genotypes of the Ahasl1 gene were compared with each other in three different genetic backgrounds. These materials were treated at the V2-V4 stage with increasing doses of imazapyr (from 0 to 480 g a.i. ha(-1)) followed by an assessment of the aboveground biomass and herbicide phytotoxicity. The estimated dose of imazapyr required to reduce biomass accumulation by 50% (GR(50)) differed statistically for the six genotypes of the Ahasl1 gene. Homozygous CLPlus (Ahasl1-3/Ahasl1-3) genotypes and materials containing a combination of both tolerant alleles (Imisun/CLPlus heterozygous stack, Ahasl1-1/Ahasl1-3) showed the highest values of GR(50), 300 times higher than the susceptible genotypes and more than 2.5 times higher than homozygous Imisun materials (Ahasl1-1/Ahasl1-1). In vitro AHAS enzyme activity assays using increasing doses of herbicide (from 0 to 100 µM) showed similar trends, where homozygous CLPlus materials and those containing heterozygous stacks of Imisun/CLPlus were statistically similar and showed the least level of inhibition of enzyme activity to increasing doses of herbicide. The degree of dominance for the accumulation of biomass after herbicide application calculated for the Ahasl1-1 allele indicated that it is co-dominant to recessive depending on the imazapyr dose used. By the contrary, the Ahasl1-3 allele showed dominance to semi dominance according to the applied dose. This last allele is dominant over Ahasl1-1 over the entire range of herbicide rates tested. At the level of enzymatic activity, however, both alleles showed recessivity to semi-recessivity with respect to the wild-type allele, even though the Ahasl1-3 allele is dominant over Ahasl1-1 at all the herbicides rates used.

Root biomass response to foliar application of imazapyr for two imidazolinone tolerant alleles of sunflower (Helianthus annuus L.).

Imisun and CLPlus are two imidazolinone tolerance traits in sunflower (Helianthus annuus L.) determined by the expression of two alleles at the locus Ahasl1. Both traits differed in their tolerance level to imazapyr -a type of imidazolinone herbicide- when aboveground biomass is considered, but the concomitant herbicide effect over the root system has not been reported. The objective of this work was to quantify the root biomass response to increased doses of imazapyr in susceptible (ahasl1/ahasl1), Imisun (Ahasl1-1/Ahasl1-1) and CLPlus (Ahasl1-3/Ahasl1-3) homozygous sunflower genotypes. These materials were sprayed at the V2-V4 stage with increased doses of imazapyr (from 0 to 480 g active ingredient ha(-1)) and 14 days after treatment root biomass of each plant was assessed. Genotype at the Ahasl1 locus, dose of imazapyr and their interaction significantly contributed (P < 0.001) to explain the reduction in root biomass accumulation after herbicide application. Estimated dose of imazapyr required to reduce root biomass accumulation by fifty percent (GR(50)) differed statistically for the three genotypes under study (P < 0.001). CLPlus genotypes showed the highest values of GR(50), 300 times higher on average than the susceptible genotypes, and almost 8 times higher than Imisun materials, demonstrating that both alleles differ in their root biomass response to foliar application of increased doses of imazapyr.

Could clinical scores guide the surgical treatment of necrotizing enterocolitis?

PURPOSE: Test the diagnostic reliability of the score for neonatal acute physiology-perinatal extension-II (SNAPPE-II) and the metabolic derangement acuity score (MDAS) as predictors of surgery in patients with necrotizing enterocolitis (NEC). METHODS: The SNAPPE-II and the MDAS were applied to 99 patients with NEC. Both the scores were calculated at the moment of diagnosis (T(0)) and when surgical assessment was required (T(1)). The main outcome was the need of surgical revision. Comparison between models was made through their receiver operator characteristics (ROC) curves. RESULTS: Thirty-five patients required surgical treatment (group A) and 64 responded to medical therapy (group B). Median SNAPPE-II was 22 versus 5 for group A (U test 621, p = 0.002) at T(0); and 22 versus 10 for group A (U test 487, p = 0.01) at T(1). Measuring the value of the SNAPPE-II as a predictor of surgery, the ROC curve was 0.69 (CI 95%, 0.57-0.80) at T(0) and 0.67 (CI 95%, 0.55-0.80) at T(1). Median MDAS were 2 for both groups A and B at T(0) (U test 890.5, p = 0.113) and 2 versus 1.5 for group A at T(1) (U test 570, p = 0.043). The ROC curve for MDAS was 0.59 (CI 95%, 0.47-0.71) at T(0) and 0.64 (CI 95%, 0.52-0.77) at T(1). CONCLUSIONS: The diagnostic performance of the SNAPPE-II offers mild results in the moment of the diagnosis of NEC, and at T(1). The MDAS is non significant at T(0) and obtains moderate results at T(1). These results do not encourage using the SNAPPE-II and the MDAS as definite tools to decide for surgical treatment of the patients affected by NEC.

Diaphragmatic avulsion with chance fracture: a rare association in the seat belt syndrome.

Traumatic diaphragmatic injuries are uncommon in children. Chance fractures are typical in adults who had motor vehicle accidents but infrequent in children. The seat belt syndrome is characterized by a spectrum of injuries caused by the compression of the abdomen by the seat belt. It can affect the abdominal wall, hollow or solid organs, and the spine, but the association between diaphragmatic rupture and Chance fracture is extremely rare. We describe the case of a child who was involved in a car accident and who presented with multiple traumas; liver and lung injuries were first detected, and the patient was managed accordingly. During the hospital stay, a right diaphragmatic avulsion and a Chance fracture, which were initially missed, were diagnosed and treated successfully. The relevance of this case lies in the low incidence of the diaphragmatic rupture and the Chance fracture in children along with their exceptional association and in the diagnosis, which might be especially difficult in the acute setting.

Vertical banded gastroplasty converted to Roux-en-Y gastric bypass: little impact on nutritional status after 5-year follow-up.

BACKGROUND: Conversion to a Roux-en-Y gastric bypass (RYGBP) has been advocated after the failure of vertical banded gastroplasty (VBG). The aim of this study was to analyze the differences in anthropometric and nutritional parameters between patients with VBG and those converted to RYGBP. METHODS: 45 patients initially underwent VBG. 22 of these patients have maintained this operation for more than 5 years (Group A) and 23 have been converted to RYGBP (Group B), after 2 years of follow-up. We analyzed anthropometric and nutritional parameters (macronutrients,micronutrients and lipid profile), and postoperative morbidity after both procedures. Data were recorded before the first operation and at 6 months, 1, 2 and 5 years follow-up. RESULTS: VBG failure rate was 51%. The 23 patients converted to RYGBP have maintained an excess weight loss (EWL) of 70% 3 years after the revision, and all the complications related to VBG disappeared. Anthropometric parameters were significantly better after RYGBP. We found no significant differences in nutritional status between both groups except for levels of iron, vitamin B(12) and transferrin saturation index, which significantly decreased in converted patients. The redo procedure had a low morbidity rate, with no mortality. CONCLUSION: More than 50% of VBGs failed after 2-year follow-up. Patients converted to RYGBP maintained mean EWL 73% at 5 years. The only significant nutritional deficiencies were iron and vitamin B(12), in patients converted to RYGBP.

Outcome of esophageal function and 24-hour esophageal pH monitoring after vertical banded gastroplasty and Roux-en-Y gastric bypass.

BACKGROUND: One of the co-morbidities frequently associated with morbid obesity is gastro-esophageal reflux disease (GERD), present in >50 % of morbidly obese individuals. We compared the anti-reflux effect of vertical banded gastroplasty (VBG) and Roux-en-Y gastric bypass (RYGBP), and their effect on esophageal function. METHODS: 10 patients underwent VBG and 40 patients underwent RYGBP. Anthropometric parameters, symptomatology of GERD, esophageal manometry (EM), isotopic esophageal emptying (IEE) and 24 hr esophageal pH monitoring were recorded in all patients preoperatively, and at 3 months and 1 year postoperatively. RESULTS: Preoperatively, there was a high prevalence of GERD, symptomatic and pH-metric in both groups (57% and 80% respectively). The preoperative values of EM and IEE parameters were within the normal range in most patients. After surgery, there was an improvement at 3 months postoperatively in both groups. 1 year after surgery, the VBG group presented symptomatic GERD in 30% and pH-metric reflux in 60% of patients while the RYGBP group presented symptomatic GERD and pH-metric reflux in 12.5% and 15% of patients, respectively. There was an increase in postoperative sensation of dysphagia in both groups (70% VBG, 30% RYGBP) one year after operation. After surgery, differences in all EM parameters were minimal, and never reached statistical significance for any group (VBG and RYGBP). The IEE showed a significantly higher percentage of esophageal retention after surgery, but this retention was always within the normal range. Both groups had an improvement in anthropometric parameters, but 1 year after surgery the results were significantly better in RYGBP patients (70% excess weight loss) than in VBG patients (46% excess weight loss). CONCLUSION: >50% of morbidly obese individuals suffer from GERD. We did not find changes in esophageal function of morbidly obese patients to explain their gastroesophageal reflux preoperatively and postoperatively. EM and IEE studies are not indicated as standard preoperative tests, except in patients with significant symptoms of gastroesophageal reflux. RYGBP is significantly better than VBG as an anti-reflux procedure, and had better weight loss.

Cost-effectiveness of laparoscopic vs open adrenalectomy: small savings in an expensive process.

BACKGROUND AND PURPOSE: Nowadays, laparoscopy has become the approach of choice for adrenalectomy, especially in cases of benign tumors <6 cm. The authors have studied, in a retrospective trial, two groups of patients who have undergone an adrenalectomy: 10 consecutive patients operated on by an open approach and 10 consecutive patients operated on by laparoscopy. METHODS: Laparoscopic adrenalectomies were performed via a transabdominal lateral approach, whereas open adrenalectomies were performed via an anterior transabdominal or posterior retroperitoneal approach. Clinical outcomes were recorded, and special attention was paid to the costs of both techniques, collecting economic data from the costs in outpatient visits, blood and urine tests, diagnostic imaging, hospital admissions prior to surgery, hospital admission for surgery, and surgical expenses. RESULTS: Operative time (110 vs 123 minutes), length of postoperative stay (3.7 vs 5.8 days), and time to oral intake (1 vs 2 days) were significantly lower in the laparoscopic group. From the economic point of view, however, there were no significant differences between laparoscopic and open groups (6,306 vs 7,581), and only surgical inhospital stay costs were significantly lower in the laparoscopic series (742 vs 1,191). All the costs generated by surgery (hospital admission for surgery plus surgical expenses) were smaller in the laparoscopic group but constituted only a small part of the general expenses for these patients. The more expensive part of the budget for every patient was the hospital admissions prior to surgery for diagnosis or preoperative treatment. CONCLUSION: Laparoscopy is a safe and comfortable approach for adrenalectomy and should be the technique of choice. From the economic point of view, laparoscopic adrenalectomy is cheaper than open adrenalectomy, but in all cases, surgical costs are only a minimal part of the budget, and the greater savings must come from the reduction in the presurgical diagnostic process.

Efficacy and cost-effectiveness of the UltraCision harmonic scalpel in thyroid surgery: an analysis of 200 cases in a randomized trial.

BACKGROUND: Thyroid surgery technique has undergone very few changes in the last century. The UltraCision harmonic scalpel (UHS) (Smithfield, RI) has been widely used in laparoscopic surgery and is documented to be safe and fast for cutting and coagulating tissue. We studied whether the use of the UHS could have advantages in thyroid surgery in terms of operative time, length of hospitalization, morbidity, and general costs. METHOD: Our study was a prospective randomized trial of thyroidectomies and lobectomies performed for benign thyroid diseases in an endocrine surgery unit between February 2001 and July 2002. Patients were randomized in two groups: group A (n=100) underwent thyroidectomy using UHS and group B (n=100) with the conventional clamp-and-tie technique. Main outcome measures were demographics, operating time, length of hospitalization, intra- and postoperative complications, sequelae, and general costs. We used the unpaired 2-tailed Student's t test and the chi2 test to compare the series. RESULTS: The two groups were similar in age and sex. Mean +/- SD operative time was shorter in the UHS group compared with the conventional technique group for both lobectomy (61 +/- 06 vs. 78 +/- 10 minutes) and total thyroidectomy (86 +/- 20 vs. 101 +/- 16 minutes). Length of hospitalization was similar in both groups (1.07 vs. 1.15 days). We did not find statistical differences between the two techniques regarding transient postoperative complications. There were no deaths, no blood transfusions, no intraoperative complications, and no postoperative definitive sequelae. The global charges for every patient were significantly less in the UHS group (985.77 +/- 107.08 euro vs. 1148.40 +/- 153.25 euro). CONCLUSION: The use of ultrasonically activated shears resulted in a reduction of 15-20% in operative time and was cost-effective compared to the conventional technique group.

[Pancreatic and periampullary tumors: morbidity, mortality, functional results and long-term survival]. / Neoplasias de páncreas y periampulares: morbimortalidad, resultados funcionales y supervivencia a largo plazo.

AIMS: To evaluate postoperative morbidity and mortality, pancreatic function and long-term survival in patients with surgically treated pancreatic or periampullar tumours. PATIENTS AND METHODS: Cohort study including 160 patients consecutively operated on: 80 pancreaticoduodenectomies (PD), 30 distal pancreatectomies (DP), 7 total pancreatectomies, 4 central pancreatic resections and 3 ampullectomies. The tumour was not resected in 36 patients. Pancreatic function was evaluated by oral glucose tolerance test, faecal fat excretion and elastase. RESULTS: Resectability rate was 77.5%. In resected patients (n = 124), 38.7% had complications with a pancreatic fistula rate of 6.4% and a mortality rate of 4%. In PD, endocrine function worsened in 41% and 58.6% had steatorrhoea; these figures in DP were 53.6% and 21.7% respectively. In the 36 non-resected patients, postoperative morbidity was 27.7% and mortality 8.3%. Two and five-year survival rates in resected patients with pancreatic cancer were 42% and 9% respectively; in malignant ampulloma 71% and 53%; in mucinous adenocarcinomas 83% and 33%; in duodenal adenocarcinoma 100% and 75%; and in distal cholangiocarcinoma 50% and 50%. CONCLUSIONS: Morbidity associated with resective pancreatic surgery is still high, but perioperative mortality is low. Endocrine and exocrine disturbances are very common depending on the type of resection. Despite the associated morbidity and functional disorders, surgery provides long-term survival in selected cases.

Molecular and biochemical characterization of an induced mutation conferring imidazolinone resistance in sunflower.

A partially dominant nuclear gene conferring resistance to the imidazolinone herbicides was previously identified in the cultivated sunflower (Helianthus annuus L.) line CLHA-Plus developed by seed mutagenesis. The objective of this study was to characterize this resistant gene at the phenotypic, biochemical and molecular levels. CLHA-Plus showed a complete susceptibility to sulfonylureas (metsulfuron, tribenuron and chlorsulfuron) but, on the other hand, it showed a complete resistance to imidazolinones (imazamox, imazapyr and imazapic) at two rates of herbicide application. This pattern was in close association with the AHAS-inhibition kinetics of protein extracts of CLHA-Plus challenged with different doses of imazamox and chlorsulfuron. Nucleotide and deduced amino acid sequence comparisons between resistant and susceptible lines indicated that the imidazolinone-resistant AHAS of CLHA-Plus has a threonine codon (ACG) at position 122 (relative to the Arabidopsis thaliana AHAS sequence), whereas the herbicide-susceptible enzyme from BTK47 has an alanine residue (GCG) at this position. Since the resistance genes to AHAS-inhibiting herbicides so far characterized in sunflower code for the catalytic (large) subunit of AHAS, we propose to redesignate the wild type allele as ahasl1 and the incomplete dominant resistant alleles as Ahasl1-1 (previously Imr1 or Ar ( pur )), Ahasl1-2 (previously Ar ( kan )) and Ahasl1-3 (for the allele present in CLHA-Plus). The higher tolerance level to imidazolinones and the lack of cross-resistance to other AHAS-inhibiting herbicides of Ahasl1-3 indicate that this induced mutation can be used to develop commercial hybrids with superior levels of tolerance and, at the same time, to assist weed management where control of weedy common sunflower is necessary.

Long-term assessment of the treatment of recurrent tracheoesophageal fistula with fibrin glue associated with diathermy.

PURPOSE: Recurrent tracheoesophageal fistula (RTF) is a serious common complication of the surgical treatment of esophageal atresia. We report the results of our technique of bronchoscopic treatment of RTF with fibrin glue (Tissucol), with a follow-up of over 1 decade. METHODS: A retrospective review between 1993 and 2004 was conducted, including all patients diagnosed with RTF and treated bronchoscopically with Tissucol, with over 1 year of follow-up. The procedure was implemented under general anesthesia using a rigid neonatal bronchoscope. A magnification chamber and previous diathermia using a urethral catheter were used in the latter 4 patients. The fibrin glue was injected through a clear catheter. The number of endoscopic sessions per patient was limited to 3. RESULTS: Seven patients were treated, with evidence of fistular closure in 6 (85%). One patient with satisfactory results, but a follow-up of 4 months, was not included. The age at bronchoscopy ranged from 14 to 20 days (mean, 16.7 days), and a total of 12 sessions were required (mean, 1.7). In the latter 4 patients, diathermia was associated with good results in all and a lower number of sessions (mean, 1.5). All patients were evaluated clinically and radiologically, and a control endoscopy was performed in 4 patients. The follow-up lasted from 2 to 11 years (mean, 7.4 years). CONCLUSIONS: Because we started to use Tissucol (1994), other authors have reported successful isolated cases, but a relatively large series and a long-term follow-up were lacking. We consider that the success of the procedure depends on several technical factors such as an early diagnosis, before epithelium is formed in the fistula, and the use of initial diathermia, associated in the latter 4 patients. The results obtained with 85% success with a follow-up over 1 year show that the fibrin adhesive is the reference substance for the treatment of RTF; we recommend its endoscopic application associated with diathermia as initial measure.

Occurrence of the rust resistance gene Lr37 from Aegilops ventricosa in Argentine cultivars of wheat

Leaf rust of wheat (Triticum aestivum L.) caused by the fungus Puccinia triticina (formerly P. recondita f. sp. tritici), is one of the most important foliar diseases of this crop. Lr37 rust resistance gene, which confers resistance in wheat against leaf rust, was introgressed into cultivated wheat from Aegilops ventricosa Tausch. Rust races with virulence to Lr37 have been identified in different countries, but it still provides resistance to a wide range of races and is useful in combination with other resistance genes. There are no reports about the presence, frequency and origin of Lr37 in Argentinean wheat cultivars. In this work, we analyzed 88 registered Argentinean wheat cultivars developed by different breeding companies and institutions during the last 15 years by means of a molecular marker which is diagnostic of the 2NS-2AS translocation which carries Lr37. Only 4 cultivars showed the amplification product associated with this chromosome fragment. These four cultivars which carry the translocated 2NS-2AS chromosome were registered by the same breeding company during the last seven years and all of them have European germplasm in their genealogy. To the best of our knowledge this is the first report of the presence of Lr37 in registered South American cultivars.

Experiencias de cuantificación del proceso de enseñanza-aprendizaje / Evaluation tests to quantify the teaching-learning process

El objetivo de este estudio es presentar una experiencia de utilización de una prueba de evaluación del tipo "progreso alcanzado" del área cognoscitiva que pretende cuantificar el proceso de enseñanza aprendizaje, con 35 alumnos de la carrera de medicina en sus trabajos prácticoa (TP) correspondientes al área de cirugía vascular. Al comenzar el TP se mostraron a los alumnos una serie de imágenes arteriográficas y tomográficas computadas en las cuales debían mencionar y señalar en forma individual las diferentes estructuras vasculares normales y patológicas a solicitud del docente. En base al porcentaje de respuestas correctas se confeccionó una tabla de resultados basales de referencia. Posteriormente se realizó el TP donde el objetivo fue "aprender a reconocer las imágenes vasculares normales y patológicas". Finalizado el mismo se procedió a una nueva evaluación individual como se había efectuado al inicio. Con este método se demostró una diferencia significativa en la comparación pre y post-TP. La cuantificación del proceso de enseñanza-aprendizaje se presenta como una herramienta práctica para medir el progreso del aprendizaje en los alumnos, para evaluar la conducción de dicho proceso por parte del docente y en especial para supervisar los tipos de estrategias de enseñanza por él empleados

Cirugía ambulatoria en patología venosa de los miembros inferiores / Ambulatory surgery in vein pathology of inferior legs

Desde enero de 1990 se efectuaron 60 operaciones por várices de miembros inferiores, 48 se realizaron en forma ambulatoria sin registrarse complicaciones. Se analizan el tipo de operaciones practicadas y la técnica anestésica utilizada. Debido a los resultados logrados durante 1990 la tendencia actual se inclina hacia una selección adecuada para cirugía ambulatoria llegando a un 100%de casos ambulatorios en el primer semestre de 1991