Diagnostic Yield of Population-Based Screening for Chronic Kidney Disease in Low-Income, Middle-Income, and High-Income Countries

IMPORTANCE

Population-based screening for chronic kidney disease (CKD) is sometimes recommended based on the assumption that detecting CKD is associated with beneficial changes in treatment. However, the treatment of CKD is often similar to the treatment of hypertension or diabetes, which commonly coexist with CKD.

OBJECTIVE

To determine the frequency with which population-based screening for CKD is associated with a change in recommended treatment compared with a strategy of measuring blood pressure and assessing glycemia.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted using data obtained from studies that evaluated CKD in population-based samples from China (2007-2010), India (2010-2014), Mexico (2007-2008), Senegal (2012), and the United States (2009-2014), including a total of 126 242 adults screened for CKD. Data were analyzed from January 2020 to March 2021.

MAIN OUTCOMES AND MEASURES

The primary definition of CKD was estimated glomerular filtration rate less than 60 mL/min/1.73 m2. For individuals with CKD, the need for a treatment change was defined as not taking an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker or having blood pressure levels of 140/90 mm Hg or greater. For individuals with CKD who also had diabetes, the need for a treatment change was also defined as having hemoglobin A1c levels of 8% or greater or fasting glucose levels of 178.4 mg/dL (9.9 mmol/L) or greater. Case finding was defined as testing for CKD only in adults with hypertension or diabetes.

RESULTS

Among 126 242 adults screened for CKD, there were 47 204 patients in the China cohort, 9817 patients in the India cohort, 51 137 patients in the Mexico cohort, 2441 patients in the Senegal cohort, and 15 643 patients in the US cohort. The mean age of participants was 49.6 years (95% CI, 49.5-49.7 years) in the China cohort, 42.9 years (95% CI, 42.6-43.2 years) in the India cohort, 51.6 years (95% CI, 51.5-51.7 years) in the Mexico cohort, 48.2 years (95% CI, 47.5-48.9 years) in the Senegal cohort, and 47.3 years (95% CI, 46.6-48.0 years) in the US cohort. The proportion of women was 57.3% (95% CI, 56.9%-57.7%) in the China cohort, 53.4% (95% CI, 52.4%-54.4%) in the India cohort, 68.8% (95% CI, 68.4%-69.2%) in the Mexico cohort, 56.0% (95% CI, 54.0%-58.0%) in the Senegal cohort, and 51.9% (51.0%-52.7%) in the US cohort. The prevalence of CKD was 2.5% (95% CI, 2.4%-2.7%) in the China cohort, 2.3% (95% CI, 2.0%-2.6%) in the India cohort, 10.6% (95% CI, 10.3%-10.9%) in the Mexico cohort, 13.1% (95% CI, 11.7%-14.4%) in the Senegal cohort, and 6.8% (95% CI, 6.2%-7.5%) in the US cohort. Screening for CKD was associated with the identification of additional adults whose treatment would change (beyond those identified by measuring blood pressure and glycemia) per 1000 adults: China: 8 adults (95% CI, 8-9 adults); India: 5 adults (95% CI, 4-7 adults); Mexico: 26 adults (95% CI, 24-27 adults); Senegal: 59 adults (95% CI, 50-69 adults); and the US: 19 adults (95% CI, 16-23 adults). Case finding was associated with the identification of 46.2% (95% CI, 45.1%-47.4%) to 86.4% (95% CI, 85.4%-87.3%) of individuals with CKD depending on the country, an increase in the proportion of individuals requiring a treatment change by as much 89.6% (95% CI, 80.4%-99.3%) in the US, and a decrease in the proportion of individuals needing GFR measurements by as much as 57.8% (95% CI, 56.3%-59.3%) in the US.

CONCLUSIONS AND RELEVANCE

This study found that most additional individuals with CKD identified by population-based screening programs did not need a change in treatment compared with a strategy of measuring blood pressure and assessing glycemia and that case finding was more efficient than screening for early detection of CKD.

Increasing access to integrated ESKD care as part of universal health coverage

The global nephrology community recognizes the need for a cohesive strategy to address the growing problem of end-stage kidney disease (ESKD). In March 2018, the International Society of Nephrology hosted a summit on integrated ESKD care, including 92 individuals from around the globe with diverse expertise and professional backgrounds. The attendees were from 41 countries, including 16 participants from 11 low- and lower-middle-income countries. The purpose was to develop a strategic plan to improve worldwide access to integrated ESKD care, by identifying and prioritizing key activities across 8 themes: (i) estimates of ESKD burden and treatment coverage, (ii) advocacy, (iii) education and training/workforce, (iv) financing/funding models, (v) ethics, (vi) dialysis, (vii) transplantation, and (viii) conservative care. Action plans with prioritized lists of goals, activities, and key deliverables, and an overarching performance framework were developed for each theme. Examples of these key deliverables include improved data availability, integration of core registry measures and analysis to inform development of health care policy; a framework for advocacy; improved and continued stakeholder engagement; improved workforce training; equitable, efficient, and cost-effective funding models; greater understanding and greater application of ethical principles in practice and policy; definition and application of standards for safe and sustainable dialysis treatment and a set of measurable quality parameters; and integration of dialysis, transplantation, and comprehensive conservative care as ESKD treatment options within the context of overall health priorities. Intended users of the action plans include clinicians, patients and their families, scientists, industry partners, government decision makers, and advocacy organizations. Implementation of this integrated and comprehensive plan is intended to improve quality and access to care and thereby reduce serious health-related suffering of adults and children affected by ESKD worldwide.

Considerations on equity in management of end-stage kidney disease in low- and middle-income countries

Achievement of equity in health requires development of a health system in which everyone has a fair opportunity to attain their full health potential. The current, large country-level variation in the reported incidence and prevalence of treated end-stage kidney disease indicates the existence of system-level inequities. Equitable implementation of kidney replacement therapy (KRT) programs must address issues of availability, affordability, and acceptability. The major structural factors that impact equity in KRT in different countries are the organization of health systems, overall health care spending, funding and delivery models, and nature of KRT prioritization (transplantation, hemodialysis or peritoneal dialysis, and conservative care). Implementation of KRT programs has the potential to exacerbate inequity unless equity is deliberately addressed. In this review, we summarize discussions on equitable provision of KRT in low- and middle-income countries and suggest areas for future research.

Global case studies for chronic kidney disease/end-stage kidney disease care

The prevalence of chronic kidney disease and its risk factors is increasing worldwide, and the rapid rise in global need for end-stage kidney disease care is a major challenge for health systems, particularly in low- and middle-income countries. Countries are responding to the challenge of end-stage kidney disease in different ways, with variable provision of the components of a kidney care strategy, including effective prevention, detection, conservative care, kidney transplantation, and an appropriate mix of dialysis modalities. This collection of case studies is from 15 countries from around the world and offers valuable learning examples from a variety of contexts. The variability in approaches may be explained by country differences in burden of disease, available human or financial resources, income status, and cost structures. In addition, cultural considerations, political context, and competing interests from other stakeholders must be considered. Although the approaches taken have often varied substantially, a common theme is the potential benefits of multistakeholder engagement aimed at improving the availability and scope of integrated kidney care.

Supportive care for end-stage kidney disease: an integral part of kidney services across a range of income settings around the world

A key component of treatment for all people with advanced kidney disease is supportive care, which aims to improve quality of life and can be provided alongside therapies intended to prolong life, such as dialysis. This article addresses the key considerations of supportive care as part of integrated end-stage kidney disease care, with particular attention paid to programs in low- and middle-income countries. Supportive care should be an integrated component of care for patients with advanced chronic kidney disease, patients receiving kidney replacement therapy (KRT), and patients receiving non-KRT conservative care. Five themes are identified: improving information on prognosis and support, developing context-specific evidence, establishing appropriate metrics for monitoring care, clearly communicating the role of supportive care, and integrating supportive care into existing health care infrastructures. This report explores some general aspects of these 5 domains, before exploring their consequences in 4 health care situations/settings: in people approaching end-stage kidney disease in high-income countries and in low- and middle-income countries, and in people discontinuing KRT in high-income countries and in low- and middle-income countries.

The global role of kidney transplantation

World Kidney Day on March 8(th) 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end-stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end-stage kidney disease include the economic limitations which, in some countries, place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high-income countries, the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The Global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end-stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end-stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation, and vaccination. Even in high-income countries, the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical, and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental, and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8 th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th, 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The global role of kidney transplantation

World Kidney Day on March 8th 2012 provides a chance to reflect on the success of kidney transplantation as a therapy for end stage kidney disease that surpasses dialysis treatments both for the quality and quantity of life that it provides and for its cost effectiveness. Anything that is both cheaper and better, but is not actually the dominant therapy, must have other drawbacks that prevent replacement of all dialysis treatment by transplantation. The barriers to universal transplantation as the therapy for end stage kidney disease include the economic limitations which, in some countries place transplantation, appropriately, at a lower priority than public health fundamentals such as clean water, sanitation and vaccination. Even in high income countries the technical challenges of surgery and the consequences of immunosuppression restrict the number of suitable recipients, but the major finite restrictions on kidney transplantation rates are the shortage of donated organs and the limited medical, surgical and nursing workforces with the required expertise. These problems have solutions which involve the full range of societal, professional, governmental and political environments. World Kidney Day is a call to deliver transplantation therapy to the one million people a year who have a right to benefit.

The Latin American Dialysis and Transplant Registry: report 2006

The Latin American Dialysis and Transplant Registry collects information on end-stage renal disease and its treatment in 20 countries of the region. By December 2005, a total of 257,974 patients were on renal replacement therapy, for a prevalence of 478.2 cases per million population; 57% were on hemodialysis, 23% on peritoneal dialysis, and 20% had a functioning kidney graft. The prevalence on renal replacement therapy continued to grow at a rate of approximately 6% annually. Hemodialysis continued to be the treatment of choice in the region, except for in Mexico, Nicaragua, El Salvador, the Dominican Republic, and Guatemala, where peritoneal dialysis predominated. Diabetes remained the leading cause of end-stage renal disease, and the highest incidences were reported in Puerto Rico (65%), Mexico (51%), Venezuela (42%), and Colombia (35%). Forty-four percent of incident patients were aged > 65 years. The rate of transplantation remained unchanged at 15 per million population, which is not sufficient to satisfy the demand of the growing number of patients in the waiting list. Close to 50% of transplants came from cadaver donors. A total of 137 simultaneous kidney-pancreas transplants were performed, 123 in Brazil, 6 in Argentina, 3 in Uruguay, 2 each in Colombia and Mexico, and 1 in Chile. In addition, 1 cardiorenal transplant (Argentina) and 1 liver-renal transplant (Chile) were reported. In conclusion, the incidence and prevalence of renal replacement therapy continued to grow. Prevention of chronic kidney disease and an integrated approach of affordable dialysis and transplantation are urgently needed in the region.

[Latin-American Dialysis and Kidney Transplantation Registry: data on the treatment of end-stage renal disease in Latin America]

Latin America, a region composed of a series of neighboring countries that share their history, Latin ancestry and language (Spanish or Portuguese), includes Mexico, Central America, the Spanish Caribbean islands, and South America. The Latin-American Dialysis and Kidney Transplantation Registry, which has been operative since 1991, collects data from 20 countries (Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Dominican Republic, Venezuela and Uruguay), where 97% of Latin Americans live. The prevalence of renal replacement therapy (RRT) has increased from 119 patients per million (pmp) in 1991 to 478.2 in 2005 (147,158 patients [57%] on chronic hemodialysis, 58,251 [23%] on peritoneal dialysis and 52,565 [20%] living with a functioning kidney graft). The incidence rate also increased from 27.8 pmp in 1992 to 167 in 2005. The increment in prevalence and incidence occurred in all Latin- American countries. The transplantation rate increased from 3,7 pmp in 1987 to 15 pmp in 2005 (7,968 kidney transplants performed this year, the cumulative number being 98,415). Access to RRT was available for every patient diagnosed with end-stage renal disease only in Argentina, Brazil, Chile, Cuba, Puerto Rico, Venezuela and Uruguay. In Latin America, the incidence and prevalence of RRT increased year by year. Only in some countries is access to RRT available to 100% of diagnosed patients. Detection and prevention programs for chronic kidney disease are needed in the region. Meanwhile, access to RRT has to be improved for everybody who needs it.

The Latin American Dialysis and Transplantation Registry (RLDT) annual report 2004

INTRODUCTION

The Latin American Dialysis and Transplantation Registry (RLDT) includes 20 national affiliates. Data are provided annually by delegates designated by the national affiliate or by the Registry's Coordinating Committee.

RESULTS

Prevalence of persons on renal replacement therapy (RRT) has increased from 192 patients per million population (pmp) in 1992 to 424 pmp in 2003, a 10% annual increment. Fifty-six percent were on hemodialysis, 23% on peritoneal dialysis, and 21% had a functioning graft. The highest prevalence was observed in Puerto Rico, and the lowest in Ecuador. Hemodialysis was the preferred treatment modality, except in El Salvador, Mexico, and Guatemala. Incidence rates varied widely; they were high in Puerto Rico (336 pmp) and Mexico (275 pmp) and low in Costa Rica (24 pmp) and Ecuador (14 pmp). Diabetes was the main reported cause of endstage renal disease (ESRD); it caused from 21% (Uruguay) to 65% (Puerto Rico) of cases. Forty percent of incident patients were > 65 years old. Access to RRT is universal in Argentina, Brazil, Cuba, Puerto Rico, Uruguay, and Venezuela but restricted in countries like Mexico and Paraguay. Main causes of death on dialysis were cardiovascular (44%) and infection (26%). Transplantation rates increased from 3.7 pmp in 1987 to 13.7 pmp in 2003, mostly from living donors (55%). The number of transplants reached 69,181 grafts.

CONCLUSION

Prevalence of RRT has increased over the years; diabetes has become the main cause of ESRD, and cardiovascular disease is the leading cause of death on dialysis. Transplantation rates, although increasing, have not matched the growing population on dialysis. Programs to promote renal health in the region are urgently needed.

Administration of eliprodil during ethanol withdrawal in the neonatal rat attenuates ethanol-induced learning deficits

RATIONALE

Prenatal exposure to alcohol can disrupt brain development, leading to a variety of behavioral alterations, including learning deficits. We have postulated that some central nervous system damage may be due to N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity that occurs during ethanol withdrawal. Consistent with this hypothesis, we previously demonstrated that administration of MK-801, an NMDA receptor antagonist, during ethanol withdrawal attenuates ethanol-related learning deficits using an animal model of fetal alcohol effects. However, MK-801 binds to the phencyclidine site, which affects all NMDA receptor subtypes and can cause adverse side effects and toxicity. Eliprodil is a more selective NMDA receptor antagonist that acts at the polyamine modulatory site of NMDA receptors.

OBJECTIVES

The purpose of this study was to determine if administration of eliprodil during ethanol withdrawal would reduce the severity of learning deficits associated with developmental alcohol exposure.

METHODS

Male rat pups were randomly assigned to ethanol-exposed or control treatments. On postnatal day (PD) 6, during a period of brain development similar to that of the mid-third trimester in humans, subjects were exposed to 6.0 g/kg ethanol or isocaloric maltose solutions via oral gavage. Twenty-four hours after the end of the ethanol treatment, during ethanol withdrawal, all subjects received an intraperitoneal injection of one of three doses of eliprodil (5, 10, or 25 mg/kg) or vehicle. On PD 40, all subjects were tested on a serial spatial discrimination reversal learning task.

RESULTS

Ethanol-exposed subjects treated with vehicle committed a significantly greater number of errors compared to controls. Administration of eliprodil during ethanol withdrawal significantly decreased the number of errors in the ethanol-exposed groups, but had no significant effect on the performance of controls.

CONCLUSION

These data support the hypothesis that NMDA receptor-mediated excitotoxicity during ethanol withdrawal contributes to fetal alcohol effects.

Single-cell analyses reveal two defects in peptide-specific activation of naive T cells from aged mice

Confocal fluorescent microscopy was used to study redistribution of membrane-associated proteins in naive T cells from young and old mice from a transgenic stock whose T cells express a TCR specific for a peptide derived from pigeon cytochrome C. About 50% of the T cells from young mice that formed conjugates with peptide-pulsed APC were found to form complexes, at the site of binding to the APC, containing CD3epsilon, linker for activation of T cells (LAT), and Zap-70 in a central area and c-Cbl, p95(vav), Grb-2, PLC gamma, Fyn, and Lck distributed more uniformly across the interface area. Two-color staining showed that those cells that were able to relocalize c-Cbl, LAT, CD3epsilon, or PLC gamma typically relocalized all four of these components of the activation complex. About 75% of conjugates that rearranged LAT, c-Cbl, or PLC gamma also exhibited cytoplasmic NF-AT migration to the T cell nucleus. Aging had two effects. First, it led to a diminution of approximately 2-fold in the proportion of T cell/APC conjugates that could relocalize any of the nine tested proteins to the immune synapse. Second, aging diminished by approximately 2-fold the frequency of cytoplasmic NF-AT migration among cells that could generate immune synapses containing LAT, c-Cbl, or PLC gamma. Thus naive CD4 T cells from old mice exhibit at least two separable defects in the earliest stages of activation induced by peptide/MHC complexes.

Endotoxin-triggered haematological interactions in Fusobacterium necrophorum infections

The haematological mechanisms in the course of liver abscess formation were evaluated. They were examined by employing viable cells of Fusobacterium necrophorum subsp. necrophorum and Fusobacterium necrophorum subsp. funduliforme in comparison with their endotoxins. Whole cell infection with F.n. necrophorum led to neutrophilia and to a concomitant monocytosis in parallel with those responses induced by the in vivo injection of its endotoxin. Viable infection with F.n. funduliforme was characterized by a sustained endotoxin-related monocytosis against neutropenia. The stimulatory impact of endotoxin on monocytes when released from a viable F.n. funduliforme infection suggested an inherently peculiar mechanism which differed from the induction of both neutrophilia and monocytosis when F.n. funduliforme endotoxin was administered alone. The neutrophilic inducing capacity of the F.n. necrophorum endotoxin was equally illustrated by its positive chemotactic effect on polymorphonuclear neutrophils in vitro. The data presented here emphasize the virulence of F.n. necrophorum viewed in reference to changes in leucocyte trafficking and as complemented by a relatively high endotoxin content.

Age-dependent alterations in the assembly of signal transduction complexes at the site of T cell/APC interaction

TCR interaction with peptide-MHC complexes triggers migration of protein kinases, actin-binding proteins, and other accessory molecules to the T cell/APC synapse. We used confocal immunofluorescence methods to show that the adapter protein LAT (linker for activation of T cells) and the guanine nucleotide exchange factor Vav also move to the APC interface in mouse CD4 T cells conjugated to anti-CD3 hybridoma cells, and in TCR-transgenic CD4 cells conjugated to APC bearing agonist (but not closely related nonagonist) peptides. The proportion of CD4+ T cells able to relocalize LAT or Vav, or to relocate cytoplasmic NT-AT (NF-ATc) from cytoplasm to nucleus, declines about 2-fold in aged mice. The decline in LAT relocalization is accompanied by a similar decline in tyrosine phosphorylation of LAT in CD4 cells stimulated by CD3/CD4 cross-linking. Two-color experiments show that LAT redistribution is strongly associated with relocalization of both NF-ATc and protein kinase C-theta among individual cells. LAT migration to the immunological synapse depends on actin polymerization as well as on activity of Src family kinases, but aging leads to only a small change in the percentage of CD4 cells that redistribute F-actin to the site of APC contact. These results suggest that defects in the ability of T cells from aged donors to move kinase substrates and coupling factors, including LAT and Vav, into the T cell/APC contact region may contribute to the decline with age in NF-ATc-dependent gene expression, and thus to defects in T cell clonal expansion.

Chemical composition of endotoxins produced by Fusobacterium necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme

The endotoxins from two recently-classified subspecies of Fusobacterium, namely F. necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme, were compared. Chemical analysis of the isolated endotoxins revealed that they were clearly different. Distinct levels of polysaccharides were demonstrated. The endotoxins isolated were devoid of heptose and 3-deoxy-D-manno-octulosonate (KDO). The endotoxins of F. n. necrophorum and F. n. funduliforme contained lipid A in a ratio of 4:1 which may account for the variations in their virulence.

Increased Zap-70 association with CD3zeta in CD4 T cells from old mice

Aging diminishes the amount of phosphotyrosine in the CD3zeta chains of resting and activated mouse CD4 T cells by about threefold and might therefore be expected to a corresponding decline in Zap-70 association with CD3zeta and in Zap-70 kinase function in CD3zeta complexes. We show here that aging leads, unexpectedly, to an approximately twofold increase in the amount of Zap-70 associated with CD3zeta in resting CD4 T cells. There is, however, no effect of age on total intracellular Zap-70 content. Cross-linking CD3 to CD4 leads to an increase of only 50% in the functional activity of Zap-70 in CD3zeta complexes from freshly isolated CD4 T cells of young donors. Compared to Jurkat and HT-2 cells, fresh T cells show both higher baseline levels and lower induced levels of Zap-70 function in CD3zeta complexes. CD4 T cells from old mice have baseline levels of Zap-70 activity similar to those seen in activated T cells from young mice, and these levels do not increase after CD3/CD4 cross-linking. Tyrosine-specific phosphorylation of Zap-70 is also higher at rest in old T cells than in young T cells and inducible only in cells from young donors. These data suggest that age-related defects in T cell activation are not likely to be attributable simply to a decline in Zap-70 association with CD3zeta or to diminished Zap-70 phosphorylation. The increase with age in CD3zeta-Zap association, despite the loss with age in CD3zeta tyrosine phosphorylation, suggests that the pattern of tyrosine phosphate groups among CD3zeta ITAM groups may be different in T cells from young and old donors or that access to ITAM regions within CD3zeta may be blocked by inter- or intramolecular steric hindrance in young CD4 T cells.

Differential tyrosine phosphorylation of zeta chain dimers in mouse CD4 T lymphocytes: effect of age

Antibody to the zeta chain of the CD3/TCR signal transduction complex precipitates a series of tyrosine-phosphorylated proteins that can be discriminated by electrophoresis in nonreducing polyacrylamide gels. Stimulation of resting mouse splenic CD4 T cells by cross-linking CD3 to CD4 leads to increases in tyrosine phosphorylation of five such proteins, of which three are likely to be dimeric forms of zeta as judged by behavior on two-dimensional gels. Two other phosphoproteins, of MW 38 and 55 kDa, also coprecipitate with the CD3zeta complex. The level of induced phosphorylation of each of these five stimulus-responsive phosphoproteins declines with donor age, T cells from 18-month-old mice being almost wholly nonresponsive. Resting T cells have only a single major form of tyrosine-phosphorylated zetazeta. Phosphorylation of this rapidly migrating species is not influenced by activation, but is about threefold lower in resting T cells from 12- to 18-month-old mice than in cells from 6-month-old animals. Thus the phosphorylation of the CD3-zeta chain of CD4 T cells from aged mice exhibits abnormalities both in the resting state and within the first 5 min of the activation process.

Structural domains of interleukin-2 receptor beta critical for signal transduction: kinase association and nuclear complex-formation

The structural domains of interleukin-2 receptor beta (IL-2R beta) were examined, characterizing the protein domains, associated phosphoproteins and nuclear complexes of IL-2-induced signal transduction. A series of IL-2R beta cytoplasmic deletion mutants were constructed and transfected into a murine pre-B-cell line, Ba/F3. The proliferative response of characterized clones was determined. A minimal linear cytoplasmic sequence required for proliferation and a sequence motif (PQPLXP) needed along with Box1-Box2 for IL-2-induced proliferation were identified. Anti-phosphotyrosine Western-blot analysis of a stimulated biologically active clone showed several IL-2-induced tyrosylphosphorylated proteins with molecular masses ranging from 45 to 116 kDa. In vitro kinase studies of biologically active clone-receptor complexes showed a 116 kDa protein (p116) to be the major tyrosine-phosphorylated component. The presence of the p116 kinase in the receptor complex correlates with IL-2-induced proliferation. An IL-2-inducible p116 kinase has recently been characterized as a Jak kinase family member and named Jak3. Nuclear complexes were formed with the GRR oligomer only when the IL-2R beta mutant supported proliferation. This led us to conclude that Box1-Box2 and PQPLXP motifs associate with Jak3 and that this association is an essential element in the IL-2 signal-transduction pathway culminating in the formation of a nuclear complex.

Pervanadate simulates the effects of interleukin-2 (IL-2) in human T cells and provides evidence for the activation of two distinct tyrosine kinase pathways by IL-2

Pervanadate has been shown to rapidly increase the level of tyrosine phosphorylation in intact cells. Because one of the most rapidly detectable events following treatment of human T cells with interleukin-2 (IL-2) is tyrosine kinase activation, we were interested to determine whether pervanadate could act to induce IL-2-associated events. We show here that pervanadate does act to induce IL-2 signal transduction pathways as determined by induction of mitogenesis and interferon gamma production in normal human T cells and the factor independent T cell line YT. Analysis of signal transduction events shows that pervanadate induces the activity of the src family of tyrosine kinases lck and fyn and the tyrosine phosphorylation of a major IL-2 responsive protein of 97 kDa. Pervanadate does not, however, induce the activity of tyrosine kinases associated with the IL-2 receptor or the phosphorylation of a major IL-2 responsive protein of 116 kDa (Jak-3). Together these data suggest that src family kinase activation is a down stream event following IL-2 stimulation and is not directly associated with the activation of the IL-2 receptor-associated tyrosine kinase. The data also imply that tyrosine phosphorylation of p116/Jak-3 is strictly associated with activation of tyrosine kinases associated with the IL-2 receptor. With the use of pervanadate as a tool, we have established a dissociation of src family kinases with IL-2 receptor activation and imply the involvement of two distinct tyrosine kinase pathways, a receptor-associated pathway closely coupled with Jak-3 phosphorylation and a downstream pathway involving src family kinase activation.

Characterization of a tyrosine kinase activity associated with the high-affinity interleukin 2 receptor complex

The IL-2 receptor complex is minimally composed of two genetically unrelated subunits of relative molecular masses 55 and 75 kDa respectively. Structural information deduced from the cDNA sequences of either subunit have not revealed significant information as to the basis of the mechanisms of IL-2 receptor signal transduction. Nevertheless, IL-2 stimulates the activation of one or more tyrosine kinases requiring the functional participation of the p75 member of the receptor complex. Here we have developed the methods to isolate the receptor complex with an associated tyrosine protein kinase. Extracts of membrane glycoproteins from activated normal human T lymphocytes and cell lines demonstrated catalytic activation of tyrosine kinase activity when stimulated with IL-2. Purification of the receptor complex with biotinylated IL-2 revealed the presence of two dominant phosphotyrosyl-proteins of approximate molecular masses 58 and 97 kDa. Denaturation gel electrophoresis followed by renaturation of proteins associated with the IL-2 receptor complex demonstrated that the 97 kDa protein had catalytic autophosphorylation activity. The results indicate that the 58 and 97 kDa phosphotyrosyl-proteins can be found to co-precipitate with the IL-2 receptor complex and that the 97 kDa protein was demonstrated to have protein kinase activity. The association of such kinases with receptors devoid of catalytic structure may represent a unique paradigm of growth-factor receptor mechanisms.

Regulation of the interleukin 2 receptor complex tyrosine kinase activity in vitro

Interleukin 2 (IL-2) has been shown to stimulate tyrosine phosphorylation of a number of proteins requiring only the p75 beta chain of the IL-2 receptor. Unlike the receptors for epidermal growth factor, insulin, and other growth factors, the p55-alpha and p75-beta chains of the IL-2 receptor have no tyrosine protein kinase domain suggesting that the IL-2 receptor complex activates protein kinases by a unique mechanism. The activation of tyrosine kinases by IL-2 in situ was studied and using a novel methodology has shown tyrosine kinase activity associated with the purified IL-2R complex in vitro. IL-2 stimulated the in situ tyrosine phosphorylation of 97 kDa and 58 kDa proteins which bound to poly(Glu,Tyr)4:1, a substrate for tyrosine protein kinases, suggesting these proteins had characteristics found in almost all tyrosine kinases. IL-2 was found to stimulate tyrosine protein kinase activity in receptor extracts partially purified from human T lymphocytes and the YT cell line. Biotinylated IL-2 was used to precipitate the high-affinity-receptor complex and phosphoproteins associated with it. The data indicated that the 97-kDa and 58-kDa phosphotyrosyl proteins were tightly associated with the IL-2 receptor complex. These proteins were phosphorylated on tyrosine residues by IL-2 stimulation of intact cells and ligand treatment of in vitro receptor extracts. Furthermore, the 97-kDa and 58-kDa proteins were found in streptavidin-agarose/biotinylated IL-2 purified receptor preparations and showed high affinity for tyrosine kinase substrate support matrixes. The experiments suggest that these two proteins are potential candidates for tyrosine kinases involved in the IL-2R complex signal transduction process.