IMMUNE MECHANISMS IN PARABIOSIS INTOXICATION

When A strain mice are placed in parabiotic union with (A x C57Bl/1)F1 hybrid partners, the parental strain partners are polycythemic and the hybrids anemic from the 5th through the 16th parabiosis days. All hybrids develop clinical intoxication between the 7th and the 12th days, and no pairs survive to 1 month. Long-term survival of parabiotic pairs can be achieved if lethally irradiated or specifically tolerant parental strain mice are united to hybrid partners. Production of tolerance by either of these methods results in elimination of anemia-polycythemia by the 12th parabiosis day and prevents intoxication in the hybrid partners. Preimmunization of the parental strain partners against the C57Bl/1 component of the hybrid leads to a considerable intensification of day 5 anemia-polycythemia. Intoxication develops in the hybrid partners between the 4th and the 6th days after union. It is concluded that anemia is primarily responsible for the syndrome of clinical intoxication. Early anemia-polycythemia on day 5 does not depend upon an immunological mechanism, but the late anemia-polycythemia appearing between days 12 and 16 is a function of the ability of the parental strain mouse to react immunologically against its hybrid partner. When neonatally thymectomized A strain mice are joined to hybrid partners, anemia-polycythemia is sustained through the 16th day and the hybrid partners develop clinical intoxication. On the other hand, when both partners are neonatally thymectomized, late anemia-polycythemia is considerably reduced, and the hybrid partners apparently do not develop clinical intoxication. It is concluded that normal hybrid mice are capable of reconstituting the immunological capacity of their thymectomized partners, whereas thymectomized hybrid mice do not have this restorative capacity. These findings are discussed in terms of their possible application to the problem of the induction of immunological tolerance in adult mice by the parabiosis procedure

Increased risk of malignant mesothelioma of the pleura after residential or domestic exposure to asbestos: a case-control study in Casale Monferrato, Italy.

The association of malignant mesothelioma (MM) and nonoccupational asbestos exposure is currently debated. Our study investigates environmental and domestic asbestos exposure in the city where the largest Italian asbestos cement (AC) factory was located. This population-based case-control study included pleural MM (histologically diagnosed) incidents in the area in 1987-1993, matched by age and sex to two controls (four if younger than 60). Diagnoses were confirmed by a panel of five pathologists. We interviewed 102 cases and 273 controls in 1993-1995, out of 116 and 330 eligible subjects. Information was checked and completed on the basis of factory and Town Office files. We adjusted analyses for occupational exposure in the AC industry. In the town there were no other relevant industrial sources of asbestos exposure. Twenty-three cases and 20 controls lived with an AC worker [odds ratio (OR) = 4.5; 95% confidence interval (CI), 1.8-11.1)]. The risk was higher for the offspring of AC workers (OR = 7.4; 95% CI, 1.9-28.1). Subjects attending grammar school in Casale also showed an increased risk (OR = 3.3; 95% CI, 1.4-7.7). Living in Casale was associated with a very high risk (after selecting out AC workers: OR = 20.6; 95% CI, 6.2-68.6), with spatial trend with increasing distance from the AC factory. The present work confirms the association of environmental asbestos exposure and pleural MM, controlling for other sources of asbestos exposure, and suggests that environmental exposure caused a greater risk than domestic exposure

THE ROLE OF THE THYMUS IN DEVELOPMENT OF IMMUNOLOGIC CAPACITY IN RABBITS AND MICE

In rabbits, complete thymectomy before the age of 5 days produced immunologic deficiency in the adult animals, as indicated by reduced antibody production to bovine serum albumin and bacteriophage T2. Homotransplantation immunity was unaffected, however. In an inbred strain of mice, complete neonatal thymectomy resulted in complete inability of the 60-day-old animals to form antibody to bacteriophage T2. Inbred mice, completely thymectomized at birth, had a deficient homograft response, indicated by acceptance of skin homografts from strains differing in both the weaker and stronger (H-2) histocompatibility antigens. Tumor transplants (mammary adenocarcinoma) were also successful across the H-2 genetic barrier in mice thymectomized at birth. Neonatal thymectomy also eliminated the Eichwald-Silmser phenomenon, rendering female mice capable of accepting isografts of male skin. Transplantation immunity in mice was also affected by later thymectomy, at 30 days of age, in certain strain combinations involving weak histocompatibility differences. Spleen and lymph node cells from mice thymectomized at birth or at 6 days of age, and sacrificed 2 months later, did not produce a graft versus host reaction in appropriate F1 hybrid recipients, indicating that such cells are immunologically inactive. Neonatal thymectomy of F1 hybrid mice, and in one strain combination thymectomy at 40 days of age, produced animals with inordinate susceptibility to runt disease (homologous disease) following injection of parent strain spleen cells 35 days (neonatal surgery) and 10 days (surgery at 40 days) later. Mice thymectomized at birth also showed growth failure and were short-lived. Studies of newborn mice indicated that they have true lymphocytes only in the thymus, and lack such cells in the spleen, lymph nodes, and gut. In normal mice, adult lymphoid structure develops gradually, beginning during the 1st week of life and continuing for the next month. In contrast, mice thymectomized at birth do not develop mature lymphoid structure: the lymph nodes and spleens tend to be small and poorly organized, and show a quantitative deficiency in lymphoid cells. It is our current working hypothesis that the thymus makes a major contribution toward the centrifugal distribution of lymphoid cells which, in turn, is essential to the full expression of immunologic capacity

Well-being in 15-year-old adolescents: a matter of relationship with school

Background Psychosomatic health complaints are significant indicators of adolescent well-being. The aim of this study is to describe the full set of interactions between health complaints and the presence of subjective resources, represented by the quality of relationships with parents and peers and by a positive school perception, in a population of 15-year-old adolescents. Smoking and alcohol consumption were also included in the analyses. Methods Bayesian networks were built for males and females separately, in order to understand the interactions among all considered variables in a representative sample of 16 018 Italian adolescents participating in the Health Behaviour in School-Aged Children survey 2009–10. Results The resulting networks show that school is the crucial node linking adolescents’ well-being with parents and peer relationships, as well as with smoking and alcohol consumption. Conclusions Adolescents' well-being, as well as the prevalence of typical risk behaviours, such as smoking and alcohol consumption, is mediated by the adolescents' academic stress. Therefore, public health interventions, to be effective, should consider addressing the school environment by making it a more inclusive environment promoting critical thinking and sense of belonging rather than just focusing on personal behaviours