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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↗
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↗
PubMed1997

Changing patterns of internal migration 1970-1990: a comparative analysis of Jews and whites in the United States.

Independently conducted yet complementary sets of data from the 1970/1971 and 1990 National Jewish Population Surveys and the U.S. censuses of the same years were used to analyze changes in the internal migration of Jews and whites during the periods 1965-1970(1971) and 1985-1990. Interstate lifetime and five-year migration rates among Jews increased to levels significantly surpassing those of whites. Adjusting Jewish migration rates for the educational achievement of their white counterparts did not have much of an effect on lifetime migration or on the recent migration of the 1970/1971 Jewish population; however, it accounted meaningfully for the migration propensities of Jews in the period 1985-1990. These findings suggest that socioeconomic status has begun to play a larger role in promoting different migration patterns than in promoting ethnic group differences. Further, the direction of Jewish migrations followed those of whites (i.e., from the North-east and Midwest to the South and West): and due to their higher migration rates, Jews have considerably narrowed the regional distribution differences between themselves and whites. I interpret these results as evidence of the weakening role of ethnicity in present-day America.

Acculturation↗
PubMed1989

On the pattern of ameloblast migration.

The kinetics of ameloblast cells in continuously growing guinea pig molars were studied using autoradiography. The results showed that there was no direct relationship between ameloblast migration rate and ameloblast production rate, which indicated that ameloblasts actively migrated coronally. It was found that ameloblast migration rate was maximal at the root apex, and then reduced to a minimum value as the ameloblasts left their proliferative compartment and migrated coronally. A multiple regression model was found to be the most suitable one to represent the ameloblast migration pattern.

Ameloblasts↗
PubMed1994

The geography of AIDS: patterns of urban and rural migration.

We sought to describe the migration patterns of patients infected with the human immunodeficiency virus (HIV) who seek health services in North Carolina. Of 390 consecutive adult patients with HIV seen at one tertiary care medical center in the southeastern United States in the summer of 1990, 340 (87%) were approached, and 325 (83%) completed surveys. Thirty-seven percent of respondents thought they had been infected and 20% were told they were infected with HIV while living outside of North Carolina. One in five patients thought they had been infected while living in a rural county and more than half now live in rural communities (population of < 50,000). Sixty percent of patients had moved to North Carolina since 1980; 61% of these were North Carolina natives. Injecting drug users were more likely than those with other modes of exposure to HIV to have been diagnosed with HIV infection out of state (34% vs 18%). Patients' reasons for moving to North Carolina included social support (88%), health reasons (54%), and better work/educational opportunities (52%). We found that most patients with HIV who seek health care services in North Carolina live in rural areas with their families, and a substantial proportion migrated in after they were diagnosed out of state. Characterizing these migration patterns is crucial for predicting the diffusion of HIV to rural areas; designing AIDS prevention strategies, education, and health service needs; and assessing federal HIV care funding policies.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Migration and disease problems: a study of pattern of migration in an endemic area of malaria in Thailand.

The preliminary results of a study of rural-rural migration in an endemic area of malaria is reported. The study on socio-economic status of migrant workers was made during the post planting season of sugarcane plantation in Tambon Nong Rhee Kanchanaburi Province. Among 9,311 population in four villages of this Tambon, 15.4% were migrants and 45.5% were from the northeast provinces of Thailand. Almost half of the migrant population came to the area for the first time and stayed for six months mostly during the sugarcane cutting season. No significant difference in experience with malaria (as recognized by the people not from blood examination) between the local population and the migrants was observed from the interview. However, the duration of migration seemed to relate with the risk of contracting malaria.

Adolescent↗
PubMed1992

A longitudinal radiographic study of the periosteal migration along the growing rabbit mandible.

In the present study, the role of the periosteum in mandibular growth was investigated. The orientation of the superficial bony spicules of rabbit mandibles was determined on dry skulls after perfusion of the animals with an India ink solution. The spicular orientation in the ramus area appeared to be toward the condyle, rostrally toward the incisors, and caudally toward the angular region. The behavior, during growth, of the periosteum in the caudal mandibular half was studied by implantation of metal periosteal and bone markers. A series of cephalograms revealed the migration pattern of the periosteal markers, and by that the migration pattern of the periosteum. It can be concluded that both the pattern of the superficial bony spicules and the periosteal migration pattern suggest a possible influence of the periosteum on mandibular growth.

Animals↗
PubMed1981

Rapid, simple method of preparing rotaviral double-stranded ribonucleic acid for analysis by polyacrylamide gel electrophoresis.

A procedure for extracting rotaviral double-stranded ribonucleic acid (RNA) directly from fecal and intestinal specimens collected from calves and pigs is described. This procedure provides a rapid, simple, reproducible method of obtaining rotaviral double-stranded RNA preparations suitable for electrophoretic analysis in polyacrylamide-agarose composite gels. The rotaviral genome electrophoretic migration pattern produced by double-stranded RNA extracted directly from a specimen by this procedure was qualitatively identical to the electrophoretic migration pattern obtained with double-stranded RNA extracted from purified rotavirus derived from the same specimen. Direct extraction of specimens containing porcine rotavirus-like virus by this procedure gave preparations that had electrophoretic migration patterns similar, but not identical, to the characteristic electrophoretic migration pattern of the rotaviral genome. Sufficient rotaviral double-stranded RNA could be extracted from 6 ml of fecal or intestinal specimen by this procedure to permit 15 or more electrophoretic assays.

Animals↗
PubMed1988

Indigenous human cutaneous leishmaniasis caused by Leishmania tropica in Kenya.

Six Leishmania isolates from 3 indigenous Kenyans (2 isolates from one patient) and 2 Canadian visitors in Kenya were characterized by cellulose acetate electrophoresis. The isolates were compared among themselves and with reference strains of Leishmania donovani, L. aethiopica, L. major, L. tropica, and L. arabica using 9 enzymes: malate dehydrogenase (MDH), malic enzyme (ME), phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), aspartate aminotransferase (ASAT), adenylate kinase (AK), mannose phosphate isomerase (MPI), glucose phosphate isomerase (GPI), and phosphoglucomutase (PGM). Enzyme migration patterns of isolates from the 3 indigenous Kenyans were indistinguishable from those of 2 L. tropica reference strains. The isolates from the 2 Canadians yielded migration patterns of 7 enzymes that were indistinguishable from those of 2 L. tropica reference strains. However, migration patterns of 2 enzymes, PGM and ME, differed from all migration patterns of the 10 reference strains. Balb/c mice were inoculated with stationary phase promastigotes cultured from 3 stabilates from the lesions of 2 of the Kenyan patients. The mice developed no gross pathological lesions in 6 months time. All of the study patients developed cutaneous leishmaniasis while living in or visiting districts in Central and Rift Valley Provinces, Kenya. This is the first report of human cutaneous leishmaniasis caused by L. tropica indigenous to Africa south of the Sahara.

Adolescent↗
PubMed1984

Distribution of radiolabelled lymph cells in lymph nodes and the migratory properties of blood lymphocytes in sheep.

The results found in this study supported the concept of lymphocyte populations with preferential migratory pathways. Preferential localization of lymphocytes in lymph nodes could not explain the non-random lymphocyte migration patterns observed in sheep. The migration of lymphocytes isolated from the blood was similar to that of lymphocytes in the efferent lymph of a subcutaneous lymph node, but was different from the migration of lymphocytes isolated from efferent intestinal lymph. The subcutaneous lymph node did not need to be selective for lymphocytes which entered from blood. However, there must be a selective entry of a population of lymphocytes with preference for migrating through mesenteric lymph nodes into efferent intestinal lymph in order to observe the differential lymphocyte migration patterns exhibited by the lymphocytes in the efferent intestinal lymph of sheep.

Animals↗
PubMed1991

Modulation of B cell maturation and migration to the thymus of SJL mice. B cell migration to the thymus.

The direct linkage of the B cell maturation process and infiltration of the thymus with mature B cells was studied in SJL mice. Phenotypically and functionally, B cells in the thymus of old SJL mice are mature B cells; IgM+, IgD+, Ly-1-, and evince a high proliferative response to lipopolysaccharide and a low one to dextran sulphate. Memory B cells can be found in the thymus of mice immunized with T-dependent or T-independent antigens. Chronic depletion and B cell maturation arrest induced by fractionated total lymphoid irradiation or by neonatal splenectomy eliminate B cells from the thymus and block their migration from the periphery to the thymus. When examined in adoptive transfer experiments, thymus B cells were found to possess a normal migration pattern and homing receptors; their migration pattern did not differ from that of lymph node or splenic B cells. It is evident, therefore, that the large number of normal functioning B cells in the thymus of SJL mice reflects a massive infiltration of the thymus by mature B cells from the periphery due to thymus dysfunction rather than to an abnormal in situ differentiation of intrathymic B cell precursors.

Animals↗