Development of an integrated genetic map of a sugarcane (Saccharum spp.) commercial cross, based on a maximum-likelihood approach for estimation of linkage and linkage phases

Sugarcane (Saccharum spp.) is a clonally propagated outcrossing polyploid crop of great importance in tropical agriculture. Up to now, all sugarcane genetic maps had been developed using either full-sib progenies derived from interspecific crosses or from selfing, both approaches not directly adopted in conventional breeding. We have developed a single integrated genetic map using a population derived from a cross between two pre-commercial cultivars ('SP80-180' x 'SP80-4966') using a novel approach based on the simultaneous maximum-likelihood estimation of linkage and linkage phases method specially designed for outcrossing species. From a total of 1,118 single-dose markers (RFLP, SSR and AFLP) identified, 39% derived from a testcross configuration between the parents segregating in a 1:1 fashion, while 61% segregated 3:1, representing heterozygous markers in both parents with the same genotypes. The markers segregating 3:1 were used to establish linkage between the testcross markers. The final map comprised of 357 linked markers, including 57 RFLPs, 64 SSRs and 236 AFLPs that were assigned to 131 co-segregation groups, considering a LOD score of 5, and a recombination fraction of 37.5 cM with map distances estimated by Kosambi function. The co-segregation groups represented a total map length of 2,602.4 cM, with a marker density of 7.3 cM. When the same data were analyzed using JoinMap software, only 217 linked markers were assigned to 98 co-segregation groups, spanning 1,340 cM, with a marker density of 6.2 cM. The maximum-likelihood approach reduced the number of unlinked markers to 761 (68.0%), compared to 901 (80.5%) using JoinMap. All the co-segregation groups obtained using JoinMap were present in the map constructed based on the maximum-likelihood method. Differences on the marker order within the co-segregation groups were observed between the two maps. Based on RFLP and SSR markers, 42 of the 131 co-segregation groups were assembled into 12 putative homology groups. Overall, the simultaneous maximum-likelihood estimation of linkage and linkage phases was more efficient than the method used by JoinMap to generate an integrated genetic map of sugarcane.

[Association of Helicobacter pylori and chronic idiopathic urticaria]

OBJECTIVES

To analise the etiological association of Hp and Idiopathic Chronic Urticaria (UCI).

MATERIAL AND METHODS

Case control study. Eighteen patients over 18 years with clinical and laboratory evidences of ICU have been studied. Previous exposure to Hp was evaluated by serum IgG for Hp. The control group, with 18 patients were paired to age, sex, race and social economic conditions. In the patients positive to Hp oral doses of amoxacilin, metronidazole and omeoprazole were given in order to eradicate the agent.

RESULTS

Twelve patients with UCI were positive to Hp (66.7%) and 6 were positive in the control group (33.3%). In the cases treated to eradicate Hp 6 had complete remission, 4 parcial remission and 2 had no improve.

CONCLUSION

There are strong evidences that Hp is an etiological factor of Urticaria. In our study the difference of 33.4% in the previous exposure to Hp between cases and controls and the positive results with the therapeutics confirm the existence of this etiological association.

The influence of reperitonization on the induction of formation of intraperitoneal adhesions by a polypropylene mesh prosthesis. An experimental study in rats

The correction of groin hernias has increasingly been performed by transperitoneal videolaparoscopic methods, using a polypropylene mesh. This could lead to an increased incidence of adhesion formation. The incidence of adhesions induced by mesh placement and the influence of reperitonization was observed on 40 male adult Wistar rats. Adhesions were significantly more common on the groups in which the prosthesis was placed (59% vs 95%; p = 0.01), as well as on the groups in which reperitonization was performed (58% vs 100%; p = 0.03). The results suggest that polypropylene mesh placement and reperitonization are each independent factors in the induction of adhesions formation.

Prospective study of strongyloidosis in patients with hematologic malignancies

Immunocompromised individuals infected with Strongyloides stercoralis may develop severe hyperinfection or disseminated disease with high mortality. Patients with hematological malignancies are at risk because of immunodepression produced either by the disease or its treatment. A prospective study was undertaken at the Hospital de Clínicas de Porto Alegre, from July 1994 to July 1995. Seventy-two (HIV negative), had 3 stool samples collected at different days and had not received recent anthelmintic therapy. Larvae, isolated in a modified Baermann method, were found in 6 patients, with a resultant prevalence of 8.3%. No complicated strongyloidosis was documented. The positive result for S. stercoralis larvae was significantly associated (p < 0.001) with eosinophilia. Knowledge of prevalence figures and incidence of severe disease is important to adequate guidelines for empirical treatment besides the rigorous search for strongyloidosis in patients with hematological malignancies.

Tracheoesophageal fistula and anomalies of thoracic vessels: their occurrence in a case of congenital rubella

Virologic, gross, and microscopic studies of rubella embryopathy were performed. The presence of esophageal atresia with tracheal fistula allied with anomalies of the thoracic vessels were seen. We believe that both the mechanical action of the anomalous vessels on the developing organ, and the vascular degenerative aortic lesions, which are identical to those described in rubella syndrome, are probable causes of the esophageal malformation.