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PubMed1983

IgA antibodies in the bile of rats. III. The role of intrathoracic lymph nodes and the migration pattern of their blast cells.

Eight weeks after rats had had their mesenteric lymph nodes (MLN) removed surgically, they were found to be still able to generate substantial titres of biliary IgA-antibodies after antigens were injected into their Peyer's patches. This suggested that systemically significant IgA production could be induced in extra-abdominal lymphoid tissue. It was found that the intrathoracic lymph nodes (ITLN) were an important source of IgA production. These nodes could be stimulated to produce biliary antibody by introducing antigen either into the peritoneal cavity or directly into the thorax. Cells forming IgA were identified in the ITLNs by haemolytic plaque assays and immunoperoxidase techniques. In spite of this, immunoblasts obtained from the ITLNs, and labelled with 125IUdR did not localize in the gut after i.v. injection to anywhere near the extent that immunoblasts from the MLN did. Instead they seemed to have a predilection for localizing in the lungs.

Animals↗
PubMed1995

STD/HIV prevention in Turkey: planning a sequence of interventions.

This study was initiated to assess which mix of early STD/HIV prevention interventions would potentially be effective, cost-effective and sustainable in Turkey; and to program an intervention sequence to maximize synergy among the interventions. During rapid assessment we: 1) reviewed past issues of 3 leading newspapers; 2) collected information on TV coverage; 3) interviewed key informants including taxicab drivers, hotel employees, grocery store owners, academicians in public health and law, investigators of STD/HIV and reproductive tract infections, and officials in the ministry of health; 4) reviewed available evidence on STD/HIV morbidity, sexual behavior patterns, migration patterns and same/opposite gender sex trade. We found: 1) discrepancies between decision makers' perceptions and social realities with respect to the epidemiology of sexual behavior and STDs, and the state of public health programs; 2) discrepancies between sexual practices and public expression regarding sexual practices; 3) economic, demographic, and political pressures in Turkey and in surrounding countries for the expansion of prostitution; 4) a sexual double standard and gender specific migration patterns which sustain a high demand for commercial sex; 5) patterns of health care seeking behaviors and provision of STD clinical services which indicate other STDs may play a very important role in spread of HIV infection; 6) an important mass media role in opinion formation; 7) consensual denial of risk for the majority based on beliefs embedded in machismo, nationalism and religion, and a resulting marginalization and externalization of STD/HIV risk; 8) high prevalence of syphilis among both Turkish and immigrant female prostitutes in Istanbul (early latent 8 and 13%; late latent 0 and 4%; previous history 9 and 22%) 9) and high rates of syphilis among male prostitutes (early latent 11%, late latent 21% and previous history 58%). We concluded that interventions should initially include, in the following order; 1) awareness raising for decision makers and opinion leaders including members of parliament and mass media; 2) awareness raising for members of the general population; 3) needs assessment and intervention development for sex workers; 4) training in HIV and other STDs for medical personnel; and 5) quality assurance and control for laboratory procedures for STDs/HIV.

Female↗
PubMed1996

Inferring patterns of migration from gene frequencies under equilibrium conditions.

A new maximum likelihood method to simultaneously estimate the parameters of any migration pattern from gene frequencies in stochastic equilibrium is developed, based on a model of multivariate genetic drift in a subdivided population. Motivated by simulations of this process in the simplified case of two subpopulations, problems related to the nuisance parameter q, the equilibrium gene frequency, are eliminated by conditioning on the observed mean gene frequency. The covariance matrix of this conditional distribution is calculated by constructing an abstract process that mimics the behavior of the original process in the subspace of interest. The approximation holds as long as there is limited differentiation between subpopulations. The bias and variance of estimates of long-range and short-range migration in a finite stepping stone model are evaluated by fitting the model to simulated data with known values of the parameters. Possible ecological extensions of the model are discussed.

Animals↗
PubMed1981

A framework for modeling interregional population distribution and economic growth.

"An integrated model is proposed to capture economic and demographic interactions in a system of regions. This model links the interregional economic model of Isard (1960) and the interregional demographic model of Rogers (1975) via functions describing consumption and migration patterns. Migration rates are determined jointly with labor force participation rates and unemployment rates."

Demography↗
PubMed1990

Spatial and temporal patterns of interstitial cell migration in Hydra vulgaris.

Interstitial cell migration was characterized in Hydra vulgaris (formerly H. attenuata) and the effects of axial position and tissue injury on migration were investigated. Migrating cells were labeled with the thymidine analog, bromodeoxyuridine, and grafted into unlabeled host polyps. Alternatively, cells were labeled directly in hosts with the fluorescent, carbocyanine dye, DiI. The results show that cell migration appeared constrained to proximal (toward the basal disk) or distal (toward the tentacles) movements, but were never lateral. Some cells moved bidirectionally. The fastest migrating cells moved an average of 28 microns/hr. Two to six percent of the gastric region interstitial cells migrated in 1 day and accumulated throughout the body column. In grafted polyps, an average of eight cells emigrated from midgastric regions every hour. Tissue injury had no observed effect on the amount of cell migration. Cells emigrating from midgastric regions showed a preference for distal accumulation, and this bias was enhanced when migrating cells originated from more distal positions in the polyp. Proximally derived tissue grafted to a more distal position also showed similar, preferential distal migration, indicating that interstitial cell migration patterns are dependent upon their position in the body column and not upon their origin. Migrating interstitial cells are slower moving and less numerous than migrating nematocytes in H. vulgaris, but since their migration patterns are similar, the migration of both cell types may be influenced by the same directional cues.

Animals↗