Experimental echinococcus infection in the mouse model: pericystic cellular immunity reaction and effects on the lymphoid organs of immunocompetent and thymectomized mice.

Echinococcus can infect man as an accidental intermediate host causing hydatid disease. The infection persists and the growth of the cysts advances, while the patient usually remains asymptomatic for years. Experimental Echinococcus infection in mice provides a well described model for the study of the parasite-host relationship that permits the evolution of the disease despite the activation of the host's immune system. The aim of the present study was to assess the immune response to Echinococcus infection in normal and thymectomized mice. For this purpose, a total of 150 mice, divided into three equal groups (A, B and C), were infected by intraperitoneal inoculation of live protoscoleses. The mice of groups B and C underwent thymectomy, two weeks prior and after the infection, respectively. The mice of each group were further divided into three subgroups and were sacrificed at three consecutive time points: 45 days, 3 and 6 months post the infection. The hydatid cysts that subsequently developed by the metacestode-lavral stage, along with the spleen and lymph nodes were excised from each mouse and histologically studied. The results revealed a marked activation of the cell-mediated immunity against the parasite at the early stages of the disease. The initial response of the host abated with time and was minimal six months after the infection suggesting a local immunosuppression state that could account for the advancement of the disease. In addition, the thymectomized mice exhibited a higher susceptibility to the infection, which corresponded to the weak and delayed cellular immunity response observed in these groups. These results suggest that the cell-mediated immunity is crucial for the defense against Echinococcus, especially early in the course of the disease where suppression of larval growth is critical for the final outcome of the infection.

A nation-based population screening for azoospermia factor deletions in Greek-Cypriot patients with severe spermatogenic failure and normal fertile controls, using a specific study and experimental design.

Y chromosome microdeletions in the azoospermia factor (AZF) locus have been associated with spermatogenic failure. The frequency of AZF deletions is estimated to be about 10-18% in subgroups of idiopathic azoospermia and severe oligospermia, whereas the deletion frequency is estimated to be about 1.5-10.6% in the general population. Patient selection criteria as well as experimental and study design are the major factors that influence the deletion frequency. We designed a nation-based population screening with a well-defined study and experimental criteria to answer, first, what is the deletion frequency in a study population of high risk for Y deletion in the Greek-Cypriot origin and second, if there are any differences in the deletion frequency in the investigated specific subgroup of patients from different geographic/ethnic origin. Eighty Greek-Cypriot patients who met the selection criteria were included in this study as well as 50 fertile control males. The sample size is quite large when compared with the size of the population. All samples were collected from all districts of the island of Cyprus as the population is of the same religious, geographic and ethnic origin. All patients and controls had detailed clinical information and at least two semen-analysis reports based on World Health Organization standards. Samples with abnormal karyotypes, obstructive azoospermia or oligospermia with >2 x 106/mL were excluded from this study. The experimental design required a referral team and laboratory to undertake the responsibility to collect all the samples, all clinical and laboratory information, isolate DNA and carry out all tests, data analysis and interpretation. In our study, Y chromosome microdeletions have been found in patients with spermatogenic failure. Under the specific patient selection criteria and experimental design, the overall frequency is 5%, while among azoospermic patients it is 12.5%. In the subgroups of patients with idiopathic cause it is 5.9% and in idiopathic azoospermia it is 14.3%. No variation in the overall deletion frequency or the specific subgroups deletion frequency were found, as compared with frequencies found in patients from different geographic/ethnic origin.