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PubMedDate not supplied

Infant mortality in a Mexican-American community: Laredo, Texas, 1950-1977.

Published infant mortality rates (IMR's) for Mexican-American populations frequently are lower than expected given the socioeconomic status (SES) of these populations. It has been speculated that this is due to bias or incompleteness in Mexican-American vital statistics. In this paper an extensive genealogical data base constructed from Catholic church records and civil records for the border city of Laredo, Texas is used to study this problem. The infant mortality probabilities (IMP's) since 1950 are compared to conventional IMR's, both based strictly on the population at risk defined by baptisms, in which the deaths are a proper subset of the denominator, and these are compared with IMR's calculated in the usual way from aggregate civil records of births and infant deaths for Laredo. We find that when these data are used, the IMR's for the most recent years are about twice the conventional rates computed from registered vital statistics.

Bias↗
PubMedDate not supplied

Long distance truck drivers in India: HIV infection and their possible role in disseminating HIV into rural areas.

In this study, a large number of truck drivers were found to be having sex with the prostitutes in rural areas along the highways of India. Some were having sex with men also. HIV/AIDS awareness and condom use was poor among them. Three out of 302 truck drivers were found to be infected with HIV. The truck drivers could play an important role in the spread of the infection in rural India.

Adolescent↗
PubMed1991

Human immunodeficiency virus and migrant labor in South Africa.

The authors investigate the impact of the migrant labor system on heterosexual relationships on South African mines and assess the implications for the future transmission of human immunodeficiency virus (HIV) infection. The migrant labor system has created a market for prostitution in mining towns and geographic networks of relationships within and between urban and rural communities. A section of the migrant workforce and a group of women dependent on prostitution for economic support appear especially vulnerable to contracting HIV infection since they are involved in multiple sexual encounters with different, changing partners, usually without condom protection. Furthermore, sexually transmitted disease morbidity is extensive in the general and mineworker populations. Historically, migration facilitated the transmission of sexually transmitted diseases and may act similarly for HIV. Problems of combating the HIV epidemic in South Africa are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Snowbirds, sunbirds, and stayers: seasonal migration of elderly adults in Florida.

OBJECTIVE: Most migration statistics in the United States focus on changes in place of usual residence, thereby missing temporary moves such as business trips, vacations, and seasonal migration. In this article, we analyze the temporary in- and out-migration of elderly adults in Florida. Our primary objectives are to develop a methodology for estimating the number of temporary migrants and to analyze their demographic characteristics. METHODS: Using survey data, we estimated the number, timing, and duration of temporary moves and the origins, destinations, and characteristics of elderly temporary migrants. We compared the characteristics of temporary in-migrants, out-migrants, and non-migrants, and we used logistic regression analysis in order to evaluate differences in those characteristics. RESULT: We estimate that Florida had more than 800,000 elderly temporary in-migrants and more than 300,000 elderly temporary out-migrants at peak times in 2005. Income, education, employment, and health status were among the major determinants of temporary migration. DISCUSSION: The temporary migration of elderly adults has a major impact on the resident populations of both sending and receiving communities. This article presents a methodology for estimating temporary migration and provides insights into migratory patterns that cannot be achieved by focusing solely on changes in place of usual residence.

Aged↗
PubMed1988

Flux ratio theorems for nonlinear membrane transport under nonstationary conditions.

We extend flux ratio theorems concerning ratios of unidirectional flux transients passed (in complementary experiments) through a medium of spatially inhomogeneous transport properties pertaining to diffusion, migration and temporary trapping of the transported substance. Any nonlinearity in the transport equations leads to a breakdown of the Ussing flux ratio theorem pertaining to all times. An integrated flux ratio theorem is proved for the case when the nonlinearity is in the kinetics of trapping, as when trapping sites can be saturated. The new theorem is shown to fail when the nonlinearity is due to a concentration-dependence of the diffusion coefficient, as in facilitated transport. The nature of a nonlinearity in membrane transport can therefore be elucidated experimentally by the use of the integrated flux ratio.

Animals↗
PubMed2001

HIV surveillance in complex emergencies.

Many studies have shown a positive association between both migration and temporary expatriation and HIV risk. This association is likely to be similar or even more pronounced for forced migrants. In general, HIV transmission in host-migrant or host-forced-migrant interactions depends on the maturity of the HIV epidemic in both the host and the migrant population, the relative seroprevalence of HIV in the host and the migrant population, the prevalence of other sexually transmitted infections (STIs) that may facilitate transmission, and the level of sexual interaction between the two communities. Complex emergencies are the major cause of mass population movement today. In complex emergencies, additional factors such as sexual interaction between forced-migrant populations and the military; sexual violence; increasing commercial sex work; psychological trauma; and disruption of preventive and curative health services may increase the risk for HIV transmission. Despite recent success in preventing HIV infection in stable populations in selected developing countries, internally displaced persons and refugees (or forced migrants) have not been systematically included in HIV surveillance systems, nor consequently in prevention activities. Standard surveillance systems that rely on functioning health services may not provide useful data in many complex emergency settings. Secondary sources can provide some information in these settings. Little attempt has been made, however, to develop innovative HIV surveillance systems in countries affected by complex emergencies. Consequently, data on the HIV epidemic in these countries are scarce and HIV prevention programs are either not implemented or interventions are not effectively targeted. Second generation surveillance methods such as cross-sectional, population-based surveys can provide rapid information on HIV, STIs, and sexual behavior. The risks for stigmatization and breaches of confidentiality must be recognized. Surveillance, however, is a key component of HIV and STI prevention services for forced migrants. It is required to define the high risk groups, target interventions, and ultimately decrease HIV and STI transmission within countries facing complex emergencies. It is also required to facilitate regional control of HIV epidemics.

Acquired Immunodeficiency Syndrome↗
PubMed1981

Fibronectin in healing rabbit corneal wounds.

Fibronectin, a glycoprotein present in plasma and extracellular matrix, is believed to be involved in cell-cell and cell-matrix interactions. Using immunofluorescence techniques, we studied the time course of appearance and distribution of fibronectin in healing rabbit corneal epithelial wounds and compared fibronectin to other selected proteins in the cornea. In the normal cornea, fibronectin was detected only in Descemet's membrane and not in the epithelial basement membrane. Shortly after wounding, fibronectin deposited on the denuded corneal surface and was a continuous prominent layer by 8 hours. The epithelium had begun to migrate over the deposited fibronectin by 22 hours and by 52 hours had completely covered the denuded surface. Fibrinogen/fibrin was also detected on the initial bare wound surface. Once the wound was reepithelialized, the subepithelial fibronectin and fibrin layer then progressively disappeared, so that by 2 weeks only a small amount was detected. Fibronectin also appeared in the deep stroma of corneas after wounding in elongated patches, a pattern suggestive of keratocyte association. Fibronectin had an inverse relationship to bullous pemphigoid antigen which was used as a marker for the lamina lucida of the epithelial basement membrane. The bullous pemphigoid antigen, which was found in the normal corneal epithelial basement membrane, was removed with the epithelium and reappeared during the wound healing when fibronectin was diminishing. IgG and albumin did not localize on the wound surface, and the diffuse staining seen in the stroma did not change during healing. These findings are compatible with the hypothesis that fibronectin and fibrin play a role in epithelial migration and temporary adhesion to the surface during corneal wound healing, at a time when the normal anchoring mechanism is lost.

Albumins↗
PubMed1991

International migration and remittances in a two-country temporary equilibrium model.

"This article examines the effects of international migration and remittances in both the source and host countries within a two-country temporary equilibrium macroeconomic model.... The objective in this article is to determine whether income, trade, and fiscal policies induce or discourage international migration; and evaluate, with emigration-cum-remittances, the analytical implications of such macroeconomic policies on income and welfare in the two countries. All policies are evaluated with respect to their effects on income and welfare of domestic nationals."

Demography↗
PubMed1987

Immigrant decisions concerning duration of stay and migratory frequency.

"The temporary and repetitive character of contemporary labor migration is explained by assuming that immigrants have a preference for location. A life-cyle model of immigrant behavior is developed to determine net lifetime income, total time allocated to home-country and foreign-country residence, and the number of migratory trips. Because of income effects, home wages and foreign wages are not symmetric in their effect on the location of work effort. It is also shown that changes in travelling costs have predictable consequences for the number of border crossings, but not for the total time spent in the foreign labor market." The emphasis is on labor migration to developed countries.

Demography↗
PubMed1987

A regional scale temporal analysis of the net migration patterns of elderly persons over time.

New England counties are grouped into categories using graphic displays of five decades of net migration rates for young and old elderly persons. Linear functions composed of social, economic, and geographic variables discriminate among the categories, yielding the following associations: positive rate counties are long-standing retirement and recreation areas; negative rate counties have large, old, declining cities; turnaround counties are nonmetropolitan counties with recently developed retirement/recreation facilities; miscellaneous counties include suburban counties with a temporary peak in net migration rates. The counties' patterns are relatively similar for young-old and old-old persons over the five decades.

Age Factors↗
PubMedDate not supplied

Are temporary migrants escapees of the one-child-per-family population policy: a revisit to the detachment hypothesis.

Using Hubei province as a case study, this paper retests the detachment hypothesis against the three conventional hypotheses regarding migration-fertility linkage (i.e., selectivity, disruption, and adaptation hypotheses) in explaining migrant and non-migrant fertility differentials in China. The analysis of yearly order-specific birth probabilities suggests that temporary migrants exhibit a significantly higher probability of having a second or higher order birth than comparable permanent migrants and non-migrants. This higher fertility among temporary migrants occurs after migration; temporary migrants actually do not differ from non-migrants in fertility before migration. But permanent migrants experience no significant change in their fertility after migration. The results lend a strong support to the detachment hypothesis, which best explains the fertility differentials between migrant and non-migrant populations in contemporary China; the separation of temporary migrants' actual residence from their official one does lead to a greater likelihood among temporary migrants to have unplanned births.

Adult↗
PubMedDate not supplied

Migration of mineral hydrocarbons into foods. 3. Cheese coatings and temporary casings for skinless sausages.

Levels of mineral hydrocarbons which have migrated from wax coatings into cheese have been determined for 20 retail samples using a gas chromatographic procedure. Contamination was limited to the outermost 2 mm of cheese in direct contact with the wax where levels of hydrocarbons were found to range from 10 to 150 mg/kg. On a whole cheese weight basis these amounted to < 1 to 27 mg/kg (< 0.2 to 3 mg/dm2 contact area). Components attributed to hydrocarbons in cheese samples remote from the waxed surface (background levels) were typically 3-5 mg/kg. Background levels were subtracted from the results for surface samples to obtain migration values. There was evidence that the surface contamination of cheese with mineral hydrocarbons occurred by a combination of diffusion into the cheese and adhesion of wax components onto its surface. Mineral hydrocarbons are used in the manufacture of the temporary casings used to mould skinless sausages. Of 33 retail products examined, including skinless sausages, hot-dog sausages and frankfurters, 25 (75%) contained levels of mineral hydrocarbons from 10 to 105 mg/kg. These hydrocarbons were shown to be present principally at the surface of the food and so could be attributed to migration. Nine other minced meat products were examined for comparison, including minced beef, pâté, sausage meat and sausages with skins. Levels of mineral oil in these products were insignificant by comparison, typically below the limit of detection of ca 4 mg/kg, indicating insignificant adventitious contamination from routes other than migration.

Animals↗
PubMed2001

Migration and gelatinases in cultured fetal, adult, and hyperoxic alveolar epithelial cells.

Alveolar epithelial cell (AEC) migration mediated by matrix metalloproteinases (MMPs) is required for lung development and repair after injury such as hyperoxia. Of specific interest in lung remodeling are the gelatinases, which are upregulated in AEC after hyperoxia. We correlated migration and gelatinase production in AEC cultured from fetal, adult, and hyperoxic rats. Fetal AEC (19-20 days) had higher MMP-2 and MMP-9 gelatinase expression than adult AEC, with fivefold higher MMP-9 activity, and were migratory through gelatin, responding to epidermal growth factor, keratinocyte growth factor, and fibroblast growth factor-10. MMP-2 and MMP-9 expression and migratory activity could be detected from the time of plating. In contrast, adult AEC migrated and expressed MMP-2 and MMP-9 proteins only after 48 h of culture. AEC from hyperoxic rats were significantly more migratory through gelatin than control adult AEC, with significantly higher MMP-9 activity. Inhibition of MMPs with doxycycline reduced the migration of AEC from hyperoxic rats to the level of control adult AEC. Fibronectin-cultured "hyperoxic" AEC acquired a temporary capacity for migration similar to the A549 lung cancer cell line, which is both highly migratory and invasive and is derived from the AEC type 2 lineage. These data suggest that MMP activity is associated with a migratory phenotype in fetal, hyperoxic, and transformed AEC in vitro, and we speculate that MMPs may play a key mechanistic role in AEC migration in vivo during lung development and repair.

Aging↗
PubMed1993

Circulatory mobility in post-Mao China: temporary migrants in Kaiping county, Pearl River Delta region.

"Since the 1980s, it has been possible for the Chinese peasant household to diversify its economic base by making use of its social networks to place members in a distant community as migrant workers. Through a microstudy of 50 such migrants in Kaiping County in the Pearl River Delta region, this article illustrates the interplay between macro, meso, and micro factors in the causes and processes of circulatory mobility in post-Mao China. It is found that Hong Kong's search for cheap labor, the PRC's household registration system, and Kaiping's strong localism provide the context in which migrants and their households have to adjust. The particular behavior pattern of these migrants also bears the stamp of their rational household decision-making processes as well as their feelings of moral obligation toward their kin in their community of origin."

Asia↗
PubMed1988

Chemotactic and haptotactic activities of fibronectin for cultured rabbit corneal epithelial cells.

A previous study reported that both fibronectin and epidermal growth factor (EGF) stimulated corneal epithelial resurfacing. Fibronectin appears in the cornea after injury, and corneal epithelial cells migrate over the temporary fibronectin matrix. To determine whether fibronectin serves as chemoattractant and haptoattractant for the directed movement of corneal epithelial cells, the directed migration of cultured rabbit corneal epithelial cells was measured in vitro using a Boyden chamber. Chemotactic and haptotactic migration were assayed separately. Fibronectin was found to stimulate attachment of corneal epithelial cells and to have chemotactic, haptotactic and chemokinetic activities for the corneal epithelial cells. In contrast, EGF had no chemotactic activity.

Animals↗
PubMedDate not supplied

Biocompatible nanofiber matrices for the engineering of a dermal substitute for skin regeneration.

Natural and synthetic biodegradable nanofibers are extensively used for biomedical applications and tissue engineering. Biocompatibility and a well-established safety profile for polycaprolactone (PCL) and collagen represent a favorable matrix for preparing a dermal substitute for engineering skin. Collagen synthesized by fibroblasts is a good surface active agent and demonstrates its ability to penetrate a lipid-free interface. During granulation tissue formation, fibronectin provides a temporary substratum for migration and proliferation of cells and provides a template for collagen deposition, which increases stiffness and tensile strength of this healing tissues. The objective of this study was to fabricate nanofiber matrices from novel biodegradable PCL and collagen to mimic natural extracellular matrix (ECM) and to examine the cell behavior, cell attachment, and interaction between cells and nanofiber matrices. Collagen nanofiber matrices show a significant (p < 0.001) level of fibroblast proliferation and increase up to 54% compared with control tissue culture plate (TCP) after 72 h. The present investigation shows that PCL-coated collagen matrices are suitable for fibroblast growth, proliferation, and migration inside the matrices. This novel biodegradable PCL and collagen nanofiber matrices support the attachment and proliferation of human dermal fibroblasts and might have potential in tissue engineering as a dermal substitute for skin regeneration.

Biocompatible Materials↗
PubMed1987

[Preoperative embolization with gelfoam powder for intracranial meningioma causing unusual peritumoral hemorrhage--with reference to the mechanism of hemorrhage].

Preoperative embolization for intracranial meningioma has been performed at many institutions and its effectiveness has been well recognized. The complications of embolization such as facial pain, fever and facial nerve palsy, et al, were mild and temporary except embolus migration into intracranial vessels, but a peritumoral hemorrhage due to preoperative embolization was extremely rare. Recently we have experienced such an unusual complication, then we describe this complication here and discuss the mechanism of hemorrhage briefly. A 73-year-old female who had the left falx meningioma underwent preoperative embolization with gelfoam powder through the transfemoral route. About 10 hours later, she developed disturbance of consciousness and right hemiplegia. At that time, CT scan showed peritumoral hemorrhage and an increase in midline shift. An emergency craniotomy was performed and total removal of the falx meningioma (Simpson grade II) and evacuation of the hematoma were done. The postoperative course was uneventful. We conclude that gelfoam powder (average particle size 40-60 mu) is a useful material for preoperative embolization but may at times cause peritumoral hemorrhage.

Aged↗