Red cell compatibility testing in baboon xenotransplantation

BACKGROUND: Although baboon ABO group and human anti-baboon heteroagglutinin (HA) titers have been considered in the selection of baboon donors for clinical hepatic xenotransplantation, the biologic role of these antibodies is not yet known. However, because of the potential importance of ABO hemagglutinins, a method for baboon ABO group determination is described, as are the titers of HA observed in both baboons and normal human donors. STUDY DESIGN AND METHODS: The ABO group of 62 baboons was determined by modified reverse typing. Baboon sera were heated and absorbed with human group O red cells. Reverse typing was then performed by standard techniques. HA titers at room temperature (RT) and in the antiglobulin test (AGT) were assessed in 10 baboons by using human red cells and in 33 normal donors by using baboon red cells. RESULTS: Ten (16%) baboons were group A, 29 (47%) were group B, 23 (37%) were group AB, and none were group O. In tests using human group O red cells, HA titers in 10 baboons ranged from 1 to 32 at RT and from negative to 64 in the AGT. All 33 normal human sera contained anti-baboon HA. Under a hemagglutination scoring system, group A persons had the lowest HA scores (17 +/− 15 at RT, 31 +/− 19 in the AGT), and group B persons had the highest HA scores (67 +/− 4 at RT, 85 +/− 9 in the AGT). CONCLUSION: Baboon ABO group can be easily determined by modified reverse serum typing. Both baboons and humans possess HAs of variable titer. Among humans, titers appear to be highest in group B individuals and lowest in group A. Additional studies are needed to determine the clinical significance of these antibodies.     

The association of Triatoma maculata (Ericsson 1848) with the gecko Thecadactylus rapicauda (Houttuyn 1782) (Reptilia: Squamata: Gekkonidae): a strategy of domiciliation of the Chagas disease peridomestic vector in Venezuela?

Objective

To investigate the bioecological relationship between Chagas disease peridomestic vectors and reptiles as source of feeding.

Methods

In a three-story building, triatomines were captured by direct search and electric vacuum cleaner search in and outside the building. Then, age structure of the captured Triatoma maculata (T. maculata) were identified and recorded. Reptiles living in sympatric with the triatomines were also searched.

Results

T. maculata were found living sympatric with geckos (Thecadactylus rapicauda) and they bit residents of the apartment building in study. A total of 1 448 individuals of T. maculata were captured within three days, of which 74.2% (1 074 eggs) were eggs, 21.5% were nymphs at different stages, and 4.3% were adults.

Conclusions

The association of T. maculata and T. rapicauda is an effective strategy of colonizing dwellings located in the vicinity of the habitat where both species are present; and therefore, could have implications of high importance in the intradomiciliary transmission of Chagas disease.     

Preliminary In Vitro Antisickilng Properties of Crude Juice Extracts of Persia Americana,Citrus Sinensis,Carica Papaya and Ciklavit?

The antisickling properties of crude juice extracts of the edible portions of three commonly consumed tropical fruits namely Persia americana, Citrus sinensis, and Carica papaya were investigated in vitro alongside a new drug preparation called Ciklavit® that has antisickling activity. Four different solvent extracts of the crude juice of each fruit including aqueous, acidic, alkaline and alcoholic extracts were prepared and their antisickling effects on sickle cell trait (HbAS) and sickle cell disease (HbSS) blood samples checked alongside Ciklavit®. Blood samples were stabilized using normal saline and the antisickling effects were checked by counting the number of sickle cells remaining after incubation of the blood samples with the crude fruit extracts and Ciklavit® for twenty-four hours. The results showed that Ciklavit® produced a sustained reduction in the number of sickle cells in both HbAS and HbSS blood samples. Also the alkaline and alcoholic extracts of P. americana and C. papaya produced significant reduction in the number of sickle cells.     

Relation between regional and global systolic function in patients with ischemic cardiomyopathy after β-Blocker therapy or revascularization

Background

To assess the relationship between improved regional and global myocardial function in patients with ischemic cardiomyopathy in response to β-blocker therapy or revascularization.

Materials and methods

Cardiovascular Magnetic Resonance (CMR) was performed in 32 patients with ischemic cardiomyopathy before and 8 ± 2 months after therapy. Patients were assigned clinically to β-blocker therapy (n = 20) or revascularization (n = 12). CMR at baseline was performed to assess regional and global LV function at rest and under low-dose dobutamine. Wall thickening was analyzed in dysfunctional, adjacent, and remote segments. Follow-up CMR included rest function evaluation.

Results

Augmentation of wall thickening during dobutamine at baseline was similar in dysfunctional, adjacent and remote segments in both patient groups. Therefore, baseline characteristics were similar for both patient groups. In both patient groups resting LV ejection fraction and end-systolic volume improved significantly (p < 0.05) at follow-up. Stepwise multivariate analysis revealed that improvement in global LV ejection fraction in the β-blocker treated patients was significantly related to improved function of remote myocardium (p < 0.05), whereas in the revascularized patients improved function in dysfunctional and adjacent segments was more pronounced (p < 0.05).

Conclusion

In patients with chronic ischemic LV dysfunction, β-Blocker therapy or revascularization resulted in a similar improvement of global systolic LV function. However, after β-blocker therapy, improved global systolic function was mainly related to improved contraction of remote myocardium, whereas after revascularization the dysfunctional and adjacent regions contributed predominantly to the improved global systolic function.