Publications by authors named "Jeffrey Hammer"

9 Publications

  • Page 1 of 1

Local Social Inequality, Economic Inequality, and Disparities in Child Height in India.

Demography 2019 08;56(4):1427-1452

The Population Research Center, University of Texas, Austin, TX, USA.

This study investigates disparities in child height-an important marker of population-level health-among population groups in rural India. India is an informative context in which to study processes of health disparities because of wide heterogeneity in the degree of local segregation or integration among caste groups. Building on a literature that identifies discrimination by quantifying whether differences in socioeconomic status (SES) can account for differences in health, we decompose height differences between rural children from higher castes and rural children from three disadvantaged groups. We find that socioeconomic differences can explain the height gap for children from Scheduled Tribes (STs), who tend to live in geographically isolated places. However, SES does not fully explain height gaps for children from the Scheduled Castes (SC) and Other Backward Classes (OBCs). Among SC and OBC children, local processes of discrimination also matter: the fraction of households in a child's locality that outrank her household in the caste hierarchy predicts her height. SC and OBC children who are surrounded by other lower-caste households are no shorter than higher-caste children of the same SES. Our results contrast with studies from other populations where segregation or apartheid are negatively associated with health.
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http://dx.doi.org/10.1007/s13524-019-00794-2DOI Listing
August 2019

Village sanitation and child health: Effects and external validity in a randomized field experiment in rural India.

J Health Econ 2016 07 20;48:135-48. Epub 2016 Apr 20.

Woodrow Wilson School, Princeton University, United States; Economics and Planning Unit, Indian Statistical Institute - Delhi, India. Electronic address:

Over a billion people worldwide defecate in the open, with important consequences for early-life health and human capital accumulation in developing countries. We report a cluster randomized controlled trial of a village sanitation intervention conducted in rural Maharashtra, India designed to identify an effect of village sanitation on average child height, an outcome of increasing importance to economists. We find an effect of approximately 0.3 height-for-age standard deviations, which is consistent with observations and hypotheses in economic and health literatures. We further exploit details of the planning and implementation of the experiment to study treatment heterogeneity and external validity.
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http://dx.doi.org/10.1016/j.jhealeco.2016.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4920645PMC
July 2016

Expression, localization, and function of junctional adhesion molecule-C (JAM-C) in human retinal pigment epithelium.

Invest Ophthalmol Vis Sci 2009 Mar 5;50(3):1454-63. Epub 2008 Dec 5.

Section for Epithelial and Retinal Physiology and Disease, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-2510, USA.

Purpose: To determine the localization of JAM-C in human RPE and characterize its functions.

Methods: Immunofluorescence, Western blot, and PCR was used to identify the localization and expression of JAM-C, ZO-1, N-cadherin, and ezrin in cultures of human fetal RPE (hfRPE) with or without si-RNA mediated JAM-C knockdown and in adult native RPE wholemounts. A transepithelial migration assay was used to study the migration of leukocytes through the hfRPE monolayer.

Results: JAM-C localized at the tight junctions of cultured hfRPE cells and adult native RPE. During initial junction formation JAM-C was recruited to the primordial cell-cell contacts and after JAM-C knockdown, the organization of N-cadherin and ZO-1 at those contacts was disrupted. JAM-C knockdown caused a delay in the hfRPE cell polarization, as shown by reduced apical staining of ezrin. JAM-C inhibition significantly decreased the chemokine-induced transmigration of granulocytes but not monocytes through the hfRPE monolayer.

Conclusions: JAM-C localizes specifically in the tight junctions of hfRPE and adult native RPE. It is important for tight junction formation in hfRPE, possibly by regulating the recruitment of N-cadherin and ZO-1 at the cell-cell contacts, and has a role in the polarization of hfRPE cells. Finally, JAM-C promotes the basal-to-apical transmigration of granulocytes but not monocytes through the hfRPE monolayer.
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http://dx.doi.org/10.1167/iovs.08-2129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2752302PMC
March 2009

Control of chemokine gradients by the retinal pigment epithelium.

Invest Ophthalmol Vis Sci 2008 Oct 30;49(10):4620-30. Epub 2008 Apr 30.

National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892-2510, USA.

Purpose: Proinflammatory cytokines in degenerative diseases can lead to the loss of normal physiology and the destruction of surrounding tissues. In the present study, the physiological responses of human fetal retinal pigment epithelia (hfRPE) were examined in vitro after polarized activation of proinflammatory cytokine receptors.

Methods: Primary cultures of hfRPE were stimulated with an inflammatory cytokine mixture (ICM): interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma. Western blot analysis and immunofluorescence were used to determine the expression/localization of the cytokine receptors on hfRPE. Polarized secretion of cytokines was measured. A capacitance probe technique was used to measure transepithelial fluid flow (J(V)) and resistance (R(T)).

Results: IL-1R1 was mainly localized to the apical membrane and TNFR1 to the basal membrane, whereas IFN-gammaR1 was detected on both membranes. Activation by apical ICM induced a significant secretion of angiogenic and angiostatic chemokines, mainly across the hfRPE apical membrane. Addition of the ICM to the basal but not the apical bath significantly increased net fluid absorption (J(V)) across the hfRPE within 20 minutes. Similar increases in J(V) were produced by a 24-hour exposure to ICM, which significantly decreased total R(T).

Conclusions: Chemokine gradients across the RPE can be altered (1) through an ICM-induced change in polarized chemokine secretion and (2) through an increase in ICM-induced net fluid absorption. In vivo, both of these factors could contribute to the development of chemokine gradients that help mediate the progression of inflammation/angiogenesis at the retina/RPE/choroid complex.
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http://dx.doi.org/10.1167/iovs.08-1816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2574653PMC
October 2008

The quality of medical advice in low-income countries.

J Econ Perspect 2008 ;22(2):93-114

Develpoment Research Group, World Bank, Washington, D.C., USA and Center for Policy Research, New Delhi, India.

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http://dx.doi.org/10.1257/jep.22.2.93DOI Listing
September 2009

Is the frequency of carisoprodol withdrawal syndrome increasing?

Pharmacotherapy 2007 Oct;27(10):1462-6

Mental Health Service, G.V. (Sonny) Montgomery Veterans Affairs Medical Center, Jackson, Mississippi 39216, USA.

Carisoprodol is a commonly used centrally acting muscle relaxant. A number of case reports have suggested that the drug may have abuse potential, presumably because it is metabolized to the anxiolytic drug, meprobamate, which is a controlled substance at the federal level. Two recent case reports described symptoms of withdrawal after the cessation of carisoprodol. We present two additional cases that support the concept of a withdrawal syndrome with this drug. Symptoms of carisoprodol withdrawal include anxiety, tremulousness, insomnia, jitteriness, muscle twitching, and hallucinations. These symptoms are most likely caused by withdrawal from the meprobamate that accumulates after large amounts of carisoprodol are ingested. Although carisoprodol is not a controlled substance at the federal level, clinicians should be aware of its significant potential for abuse.
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http://dx.doi.org/10.1592/phco.27.10.1462DOI Listing
October 2007

Location, location, location: residence, wealth, and the quality of medical care in Delhi, India.

Health Aff (Millwood) 2007 May-Jun;26(3):w338-51. Epub 2007 Mar 27.

Development Research Group, World Bank, Washington, DC, USA.

There are seventy medical care providers within walking distance of every household in Delhi. However, inequalities in health outcomes persist among the rich and poor, which might reflect differences in the quality of available care. This paper shows that providers visited by the poor were indeed less knowledgeable than those visited by the rich. There is strong evidence of inequalities in access, with lower competence among private- and public-sector providers in poor neighborhoods, but no evidence of inequalities in choices. Practical policy options include targeted information to patients on provider competence and improving the allocation of public doctors across poor and rich neighborhoods.
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http://dx.doi.org/10.1377/hlthaff.26.3.w338DOI Listing
July 2007

Missing in action: teacher and health worker absence in developing countries.

J Econ Perspect 2006 ;20(1):91-116

South Asia Human Development, World Bank, Washington, D.C., USA.

In this paper, we report results from surveys in which enumerators make unannounced visits to primary schools and health clinics in Bangladesh, Ecuador, India, Indonesia, Peru and Uganda and recorded whether they found teachers and health workers in the facilities.
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http://dx.doi.org/10.1257/089533006776526058DOI Listing
December 2006

Confluent monolayers of cultured human fetal retinal pigment epithelium exhibit morphology and physiology of native tissue.

Invest Ophthalmol Vis Sci 2006 Aug;47(8):3612-24

National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.

Purpose: Provide a reproducible method for culturing confluent monolayers of hfRPE cells that exhibit morphology, physiology, polarity, and protein expression patterns similar to native tissue.

Methods: Human fetal eyes were dissected on arrival, and RPE cell sheets were mechanically separated from the choroid and cultured in a specifically designed medium comprised entirely of commercially available components. Physiology experiments were performed with previously described techniques. Standard techniques were used for immunohistochemistry, electron microscopy, and cytokine measurement by ELISA.

Results: Confluent monolayers of RPE cell cultures exhibited epithelial morphology and heavy pigmentation, and electron microscopy showed extensive apical membrane microvilli. The junctional complexes were identified with immunofluorescence labeling of various tight junction proteins. The mean transepithelial potential (TEP) was 2.6 +/- 0.8 mV, apical positive, and the mean transepithelial resistance (R(T)) was 501 +/- 138 Omega . cm(2) (mean +/- SD; n = 35). Addition of 100 microM adenosine triphosphate (ATP) to the apical bath increased net fluid absorption from 13.6 +/- 2.6 to 18.8 +/- 4.6 microL . cm(-2) per hour (mean +/- SD; n = 4). In other experiments, VEGF was mainly secreted into the basal bath (n = 10), whereas PEDF was mainly secreted into the apical bath (n = 10).

Conclusions: A new cell culture procedure has been developed that produces confluent primary hfRPE cultures with morphological and physiological characteristics of the native tissue. Epithelial polarity and function of these easily reproducible primary cultures closely resemble previously studied native human fetal and bovine RPE-choroid explants.
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http://dx.doi.org/10.1167/iovs.05-1622DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1904392PMC
August 2006