Aging and infectious diseases in the developing world

The Optimal Management of Acute Febrile Encephalopathy in the Aged Patient: A Systematic Review

The elderly comprise less than 13 percent of world population. Nonetheless, they represent nearly half of all hospitalized adults. Acute change in mental status from baseline is commonly seen among the elderly even when the main process does not involve the central nervous system. The term "geriatric syndrome" is used to capture those clinical conditions in older people that do not fit into discrete disease categories, including delirium, falls, frailty, dizziness, syncope, and urinary incontinence. Despite the growing number of elderly population, especially those who require hospitalization and the high burden of common infections accompanied by encephalopathy among them, there are several unresolved questions regarding the optimal management they deserve. The questions posed in this systematic review concern the need to rule out CNS infection in all elderly patients presented with fever and altered mental status in the routine management of febrile encephalopathy. In doing so, we sought to identify all potentially relevant articles using searches of web-based databases with no language restriction. Finally, we reviewed 93 research articles that were relevant to each part of our study. No prospective study was found to address how should AFE in the aged be optimally managed.

The prevalence and clinical manifestations of delirium in sub-Saharan Africa: a systematic review with inferences

BACKGROUND

In high-income countries with ageing populations, delirium is most prevalent in older adults and in palliative and intensive care settings. The prevalence and aetiology of delirium are likely to differ in low income countries, including sub-Saharan Africa (SSA), due to different population demographics, disease burden and exposure to pathogens. We reviewed published literature relating to the prevalence, clinical features and underlying causes of delirium in SSA and compare this with that published in high-income countries in order to identify knowledge and clinical service gaps, and priorities for further research.

METHODS

We performed a narrative review by comprehensively searching the following databases: Medline, PsychInfo, Embase and PubMed. Studies published between January 1 1975 and December 31 2013 in all languages, including the terms 'delirium', 'acute brain syndrome', 'organic brain syndrome', or 'acute confusion' originating from SSA were included. In addition, reference lists of included articles and online databases of African medical literature were hand-searched. We also included case series and case reports due to paucity of published studies.

RESULTS

We identified a total of 46 relevant studies. Delirium was the main focus of only one cross-sectional study, whereas most included delirium in studies on neuropsychiatric conditions. Only two studies reported prevalence in older adults. Most studies reported very low (<2%) delirium prevalence, whereas delirium in psychiatric inpatient and outpatient settings was higher than expected (18.2%-29.9%). Descriptive studies of 'bouffee delirante' from psychiatry settings were often describing delirium. Infection and HIV seropositivity were common associations of delirium throughout these studies. There were no studies of intensive, critical or surgical care settings or of management strategies.

CONCLUSIONS

We currently know very little about the prevalence, presentation and aetiology of delirium in developing countries. This knowledge gap should be tackled with some urgency, in order to address questions of screening, diagnosis, prevention and management in this setting.

Profile and treatment outcomes of tuberculosis in the elderly in southeastern Nigeria, 2011-2012

Background

The demographic transition and increasing life expectancy in Africa has lead to a rising elderly population. In Nigeria, little is known about the profile of and treatment outcomes of tuberculosis (TB) in the elderly.

Methods

Retrospective cohort study of adult TB patients treated between January 2011 and December 2012 in two large health facilities in Nigeria. The demographic, clinical and treatment outcomes of patients aged 60 and older were compared with those aged 15 to 59 years.

Results

Elderly (≥60 years) TB patients accounted for 12.7% of all (1668) adult TB enrolled. Elderly patients had a higher proportion of men compared to non-elderly (64.2% vs 56.8%; p = 0.043); but a lower proportion of smear-positive TB at baseline (40.7% vs 65.8%; p<0.001). A higher proportion of elderly patients failed to smear convert after the intensive phase of treatment (23.7% vs 19.8%; p = 0.06), and overall elderly patients had lower treatment success rates (68.9% vs 77.1%; p = 0.009). Unsuccessful outcomes were mainly due to higher default and deaths in the elderly. The risk factors for unsuccessful outcomes in the elderly were: extrapulmonary TB case (adjusted odds ratio (aOR) 10.9; 95% confidence interval (CI) 1.1–108), and HIV co-infection (aOR 3.6; CI 1.1–11.7).

Conclusions

Treatment outcomes of elderly TB patients were inferior to non-elderly adults with higher death and default rates being implicated. With the rising elderly population, specific strategies are needed to quickly address TB management in the elderly in resource-limited settings.

Patient automedication and professional prescription pattern in an urgency service in Brazil

Several studies have indicated an increased resistance of microorganisms resulting from the widespread use of antimicrobial agents. However, few data are available in the dental literature. The aim of this study was to conduct a survey on the patterns of patient usage of antimicrobial prescriptions agents by dentists. A retrospective cross-sectional study was based on the medical records of 223 patients who sought treatment at the Urgency Service, from a Dental School in the South of Brazil, from March 2009 to March 2011. A specific data sheet was used, with questions regarding: patient age and gender; the main complaint; medications used prior to the service; final diagnosis; proposed dental treatment (including prescription medications); and characteristics of the final prescription. Descriptive and inferential statistics were obtained. There was a high frequency of antibiotic use prior to attendance by young patients (Fisher's exact test, p < 0.05). Toothache of endodontic origin was the most frequent patient complaint (72.6%). Endodontic procedures were the measures most frequently adopted to treat the pain (31.2%). The frequency of patient use of antimicrobials prior to the appointment was 14.3%. According to patient records, 83.9% had no systemic drug prescription after receiving urgency treatment. There were few antimicrobial prescriptions after the urgency treatment. The most frequently prescribed agents were amoxicillin, chlorhexidine, and metronidazole. Local measures were more frequently used than systemic approaches to treat urgencies of dental origin. Antimicrobial agents were not frequently prescribed as adjunctives to local administered at the urgency service.

High prevalence of Strongyloides stercoralis infection among the elderly in Brazil

Little is known about the frequency of intestinal parasites in the elderly due to a lack of attention given to the occurrence of these infections among older adults. This study compares the frequency of Strongyloides stercoralis and other enteroparasites between elderly living in nursing homes (n = 100) and those noninstitutionalized (n = 100) from Uberlândia, state of Minas Gerais, southeastern Brazil, associated with data of epidemiological and socio-demographic conditions. Through coproparasitological examination of both groups, enteroparasites were detected in 15 of 200 individuals examined (7.5%; CI: 5.1- 9.9). S. stercoralis was the most frequent parasite 10/200 (5%; CI: 4.2-5.8), being significantly higher in males and in individuals with autonomy for daily living activities. There were no statistical differences in the prevalence of parasites between the two groups compared. In conclusion, S. stercoralis infection was highly prevalent in elderly patients and it does not depend on whether the individual was institutionalized or not.

The immune system and aging: a review

Abstract The concept of immunosenescence reflects age-related changes in immune responses, both cellular and serological, affecting the process of generating specific responses to foreign and self-antigens. The decline of the immune system with age is reflected in the increased susceptibility to infectious diseases, poorer response to vaccination, increased prevalence of cancer, autoimmune and other chronic diseases. Both innate and adaptive immune responses are affected by the aging process; however, the adaptive response seems to be more affected by the age-related changes in the immune system. Additionally, aged individuals tend to present a chronic low-grade inflammatory state that has been implicated in the pathogenesis of many age-related diseases (atherosclerosis, Alzheimer's disease, osteoporosis and diabetes). However, some individuals arrive to advanced ages without any major health problems, referred to as healthy aging. The immune system dysfunction seems to be somehow mitigated in this population, probably due to genetic and environmental factors yet to be described. In this review, an attempt is made to summarize the current knowledge on how the immune system is affected by the aging process.

Role of Toll-like receptor 2 (-196 to -174) polymorphism in susceptibility to pulmonary tuberculosis in Pakistani population

Tuberculosis (TB) is a global public health problem and a source of preventable deaths each year, with 8.8 million new cases of TB and 1.6 million deaths worldwide. Pakistan ranks sixth on the list of 22 high-burden tuberculosis countries in the world. The transitions from infection to clinical disease are very few signifying that host-defence factors could lead to the development of active disease. Toll-like receptor (TLR) 2 polymorphisms have been associated with regulation of TLR expression and development of active TB. In this study, blood samples of 187 subjects including 100 healthy and 87 TB positive were collected from three districts of Pakistan. DNA was extracted from blood and TLR 2 (-196 to -174del) polymorphism was analysed by polymerase chain reaction (PCR). The results suggest that the frequency of -196 to -174del/del polymorphism of TLR2 was significantly higher in TB-positive patients compared with healthy. Results revealed that (-196 to -174del) polymorphism may increase the susceptibility to TB in healthy population of Pakistan. Moreover, males with heterozygous genotype (I/D) are more prone to TB than females with the same genotype. The occurrence of TB infection has been found positively associated with the age, suggesting that the population within the range of 21-45 years is more susceptible to Mycobacterium tuberculosis than other age groups studied. A significant association is also observed between smoking and the chances of developing TB, confirming that smoking strongly promotes its incidence.

Rational use of medicines: prescribing indicators at different levels of health care

This multicenter study aimed to investigate prescribing patterns of drugs at different levels of health care delivery in university-affiliated outpatient clinics located in eight cities in the South and Midwest of Brazil. All prescriptions collected were analyzed for various items, including WHO prescribing indicators. A total of 2,411 prescriptions were analyzed, and 469 drugs were identified. The number of drugs prescribed per encounter, the frequency of polypharmacy, and the percentage of encounters with at least one injection or antibiotic prescribed were higher in centers providing primary health care services, compared to those where this type of care is not provided. Most drugs (86.1%) were prescribed by generic name. In centers with primary health care services, drug availability was higher, drugs included in the National and Municipal Lists of Essential Medicines were more frequently prescribed, and patients were given more instructions. However, warnings and non-pharmacological measures were less frequently recommended. This study reveals trends in drug prescribing at different levels of health care delivery in university-affiliated outpatient clinics and indicates possible areas for improvement in prescribing practices.

Increased IL-21 secretion by aged CD4+T cells is associated with prolonged STAT-4 activation and CMV seropositivity

Advancing age leads to significant decline in immune functions. IL-21 is produced primarily by T follicular helper (Tfh) cells and is required for effective immune cell functions. Here we compared the induction of IL-21 in aged and young subjects. Our investigation demonstrates that CD4+T cells from healthy elderly individuals (age ≥ 65) secreted significantly higher levels of IL-21 on priming with aged and young dendritic cells (DC). Though the aged and young DCs secreted comparable levels of IL-12 on stimulation with anti-CD40 antibody and LPS, culture of DCs with aged CD4+ T cells resulted in increased production of IL-21 as compared to that with young CD4+ T cells. Further examination revealed that the response of aged naïve CD4+ T cells to IL-12 was altered, resulting in increased differentiation of aged Th cells towards Tfh cells. Investigation into the signaling mechanism suggested that phosphorylation of STAT-4 in response to IL-12 was sustained for a longer duration in aged CD4+ T cells as compared to CD4+ T cells from young subjects. Additional analysis demonstrated that increased IL-21 secretion correlated with chronic CMV infection in aged subjects. These findings indicate that chronic CMV infection alters the response of aged CD4+ T cells to IL-12 resulting in an increased secretion of IL-21 and that aging affects Tfh cell responses in humans which may contribute to age-associated inflammation and immune dysfunctions.

Epidemiology of tuberculosis immunology

Immunological impairment plays a major role in the epidemiology of TB. Globally, the most common causes of immunological impairment are malnutrition, diabetes, HIV/AIDS, aging, and smoking. With the notable exception of HIV, each factor leads to relatively mild immunological impairment in individuals. However, as these conditions affect a significant proportion of the population, they contribute substantially to the incidence of TB at a global scale. Understanding immunological impairment is central to understanding the global TB pandemic, and vital to the development of effective disease control strategies.

Ending neglect of older people in the response to humanitarian emergencies

Unni Karunakara and Frances Stevenson argue that humanitarian policy and practice must adapt to ensure that the needs of older people in humanitarian emergencies are addressed.

Report of the ad-hoc consultation on aging and immunization for a future WHO research agenda on life-course immunization

WHO convened a meeting of around 30 experts to address the topic of aging and immunization in March 2011 in Geneva. The purpose of the meeting was to develop a global research agenda to eventually inform WHO policy recommendations regarding immunization beyond childhood and into old age. This issue is becoming more critical, since the population aged 60 and above will reach two billion people - three-quarters of whom will be in developing countries - in the next 40 years. The meeting reviewed current knowledge and gaps in information about: (1) the epidemiology of infectious diseases in the elderly in developed and developing countries and their contribution to disability in old age; (2) the deterioration of the immune system with age ("immune senescence") and possible ways to measure and counteract it; and (3) immunization approaches to maintain or improve health in older persons. These approaches include the concept of a "life-course vaccination" schedule to help sustain immunity to vaccine-preventable diseases beyond childhood and into old age; strategies to strengthen older persons' responses to vaccines (e.g., by adding adjuvants to vaccines, increasing vaccine dosage, and intradermal vaccine administration); and the possible development of new vaccines targeted specifically for older adults. Participants proposed priority research topics as well as strategies to facilitate and coordinate the research, including the establishment of networks of collaborators, with WHO playing a key coordinating role.

Tuberculosis in ageing: high rates, complex diagnosis and poor clinical outcomes

BACKGROUND

worldwide, the frequency of tuberculosis among older people almost triples that observed among young adults.

OBJECTIVE

to describe clinical and epidemiological consequences of pulmonary tuberculosis among older people.

METHODS

we screened persons with a cough lasting more than 2 weeks in Southern Mexico from March 1995 to February 2007. We collected clinical and mycobacteriological information (isolation, identification, drug-susceptibility testing and IS6110-based genotyping and spoligotyping) from individuals with bacteriologically confirmed pulmonary tuberculosis. Patients were treated in accordance with official norms and followed to ascertain treatment outcomes, retreatment, and vital status.

RESULTS

eight hundred ninety-three tuberculosis patients were older than 15 years of age; of these, 147 (16.5%) were 65 years of age or older. Individuals ≥ 65 years had significantly higher rates of recently transmitted and reactivated tuberculosis. Older age was associated with treatment failure (OR=5.37; 95% CI: 1.06-27.23; P=0.042), and death due to tuberculosis (HR=3.52; 95% CI: 1.78-6.96; P<0.001) adjusting for sociodemographic and clinical variables.

CONCLUSIONS

community-dwelling older individuals participate in chains of transmission indicating that tuberculosis is not solely due to the reactivation of latent disease. Untimely and difficult diagnosis and a higher risk of poor outcomes even after treatment completion emphasise the need for specific strategies for this vulnerable group.

Epidemiology and predictors of a poor outcome in elderly patients with candidemia

BACKGROUND

Candidemia affects patient populations from neonates to the elderly. Despite this, little information is available about the epidemiology of candidemia in elderly patients.

METHODS

We performed a retrospective analysis of 987 episodes of candidemia in adults (>14 years of age) from the databases of three laboratory-based surveys of candidemia performed at 14 tertiary care hospitals. Patients aged ≥60 years were considered elderly (group 1, n=455, 46%) and were compared to younger patients (group 2, n=532, 54%) regarding demographics, underlying diseases, comorbidities, exposure to medical procedures, species, treatment, and outcome.

RESULTS

The median APACHE II score was significantly higher in the elderly patients (19 vs. 15, p=0.03). Variables that were observed significantly more frequently in elderly patients included admission to an intensive care unit, diabetes mellitus, renal failure, cardiac disease, lung disease, receipt of antibiotics or H2 blockers, insertion of a central venous catheter, mechanical ventilation, and candidemia due to Candida tropicalis. The 30-day mortality of elderly patients was significantly higher than that of younger patients (70% vs. 45%, p<0.001). Factors associated with higher mortality by multivariate analysis included APACHE II score and being in group 1 (elderly). Factors associated with mortality in elderly patients were lung disease and the receipt of mechanical ventilation.

CONCLUSIONS

Elderly patients account for a substantial proportion of patients with candidemia and have a higher mortality compared to younger patients.

Age-associated impaired plasmacytoid dendritic cell functions lead to decreased CD4 and CD8 T cell immunity

Increased susceptibility to infections, particularly respiratory viral infections, is a hallmark of advancing age. The underlying mechanisms are not well understood, and there is a scarcity of information regarding the contribution of the innate immune system, which is the first line of defense against infections. In the present study, we have investigated the effect of advancing age on plasmacytoid dendritic cell (PDC) function because they are critical in generating a robust antiviral response via the secretion of interferons (IFN). Our results indicate that PDCs from the aged are impaired in their capacity to secrete IFN-I in response to influenza virus and CPG stimulation. Additionally, we observed a severe reduction in the production of IFN-III, which plays an important role in defense against viral infections at respiratory mucosal surfaces. This reduction in IFN-I and IFN-III were a result of age-associated impaired phosphorylation of transcription factor, IRF-7. Furthermore, aged PDCs were observed to be impaired in their capacity to induce perforin and granzyme in CD8 T cells. Comparison of the antigen-presenting capacity of aged PDC with young PDC revealed that PDCs from aged subjects display reduced capacity to induce proliferation and IFN-gamma secretion in CD4 and CD8 T cells as compared with PDCs from young subjects. In summary, our study demonstrates that advancing age has a profound effect on PDC function at multiple levels and may therefore, be responsible for the increased susceptibility to infections in the elderly.

[Uncomplicated malaria treatment in the Brazilian Amazon: knowledge, practices and perceptions of health workers in high-incidence municipalities]

Malaria control in Brazil is based on early diagnosis and adequate and timely treatment as strategies for a rapid and long-lasting cure. Clinical consequences and resistance to antimalarials may arise from problems in prescribing, dispensing and in acceptance of therapeutic regimens by healthcare workers. We studied knowledge and practices, perceptions and attitudes of health workers participating in pharmaceutical services for malaria, regarding the official protocol and the possible flaws in therapy. Health workers from six municipalities in the Brazilian Amazon were interviewed. Speech analysis was employed as a technique to determine analytical categories and to organize data. There was only 1 physician among the 63 interviewees, the others were health technicians carrying out diagnosis, therapy indication and dispensing of antimalarial treatment. Training time and period since course completion varied. Flaws in the adherence to the national protocol included therapy indication, dispensing and counseling. Health workers need knowledge to face disease and treatment specificities. Holding accountable health workers that are unprepared and unfit for the job may indicate the need for adequacy in policies regarding adequate training and hiring of human resources.

Cytomegalovirus infection- and age-dependent changes in human CD8+ T-cell cytokine expression patterns

T cells are strongly affected by immune aging, a phenomenon that leads to increased susceptibility to infections and decreased vaccination efficacy in elderly individuals. Cytomegalovirus (CMV) infection induces vigorous T-cell immune responses in humans and is thought to be a driving force of immune aging. In the present study we analyzed CMV-induced quantitative and qualitative differences in the cytokine-expressing T-cell repertoire from individuals of different age groups after in vitro stimulation. The CMV pp65 peptide pool and the superantigen Staphylococcus enterotoxin B (SEB) induced higher proportions of CD8+ effector T cells expressing gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and granulocyte-macrophage colony-stimulating factor in the oldest study group, while only SEB induced increased responses in the middle-aged study group. Notably, CMV-specific multiple cytokine expression patterns revealed higher proportions of IFN-gamma- and TNF-alpha-coexpressing CD8+ T cells exclusively in the oldest study group. These qualitative differences were absent in SEB-induced CD8+ effector T cells, although quantitative differences were detected. We report age-dependent qualitative changes in CMV-specific CD8+ T-cell cytokine patterns which are biocandidate markers of immune exhaustion in elderly individuals.

Perceived and objective neighborhood environment attributes and health related quality of life among the elderly in Bogotá, Colombia

This study examines associations between neighborhood environment attributes and health related quality of life (HRQOL) and self-rated health (SRH) among older adults (60 years and over) in Bogotá, Colombia. Perceived and objective neighborhood environmental characteristics were assessed in a cross sectional multilevel design with 1966 older adults within 50 neighborhoods. Outcome variables included HRQOL (physical and mental dimensions) and SRH measured with the Spanish version of the Short Form 8 (SF-8). Independent variables included perceived and objective neighborhood characteristics as well as self-reported levels of walking. Hierarchical linear and logistic regression models were used for the analysis. Among perceived neighborhood characteristics, safety from traffic was positively associated with both HRQOL dimensions and SRH. Having safe parks was positively associated with the mental dimension of HRQOL and with SRH. Street noise was negatively associated with both HRQOL dimensions. Regarding objective neighborhood characteristics, residing in areas with more than eight percent of land covered by public parks was positively associated with SRH. Objective and perceived neighborhood characteristics could provide insight into potential interventions among older adults from rapidly urbanizing settings in Latin America.

Nutrition, health, and aging in sub-Saharan Africa

The proportion of the population that is > or = 60 years of age in sub-Saharan Africa (SSA) is increasing rapidly and is likely to constrain healthcare systems in the future. Nevertheless, the elderly are not a health policy priority for African countries. This paper reviews the nutritional and health status of older adults in SSA and their determinants. Literature was abstracted through the Medline, Google Scholar, and Dogpile databases using the following search terms: sub-Saharan Africa, older adults, nutrition, health. Findings showed that up to half (6-48%) of elderly Africans in SSA are underweight and almost a quarter (2.5-21%) are overweight, while 56% of older South Africans are obese. Low-quality diets contribute to poor nutritional status. Poverty, HIV/AIDS, and complex humanitarian emergencies are major determinants of undernutrition. Effective interventions need to consider socioeconomic, health, and demographic factors; social pensions may be the most cost-effective option for improving the health and nutritional status of the elderly in SSA.

Outcome and immune responses after Brucella abortus infection in young adult and aged mice

Aging results in a general waning of immunity and enhanced susceptibility to many intracellular pathogens. However, in some instances, aging is accompanied by alternative immune responses that can be equal to, or even more effective, than those of young adults. Brucella spp. are intracellular bacteria and important human and animal pathogens, but there are no data regarding the effect of age on host defense in brucellosis. Young or old adult mice (DBA/2 or BALB/c) were infected with either an attenuated B. abortus strain that over-expressed the Brucella superoxide dismutase (strain RB51-SOD) or a fully virulent strain (strain 2308). Survival, organism burden in the spleen, and immune responses were assessed. All young adult and aged mice survived infection with RB51-SOD (up to 6 x 10(8) cfu) or strain 2308 (up to 8 x 10(8) cfu). Old mice had a lower organism burden in the spleen than young adult mice five or more weeks after infection. Antibody and cytokine responses were Th1-focused in young adult mice, but Th-mixed in older mice, including evidence of the newly defined Th17 subtype immune response. Immunization with the RB51-SOD strain provided protection vs. strain 2308 challenge in young and aged BALB/c, but only young adult DBA/2 mice. Thus, clinical outcomes of Brucella infection in aged mice are equal or superior to those of young adult mice; immune responses in older mice are less-Th1 specific suggesting alternate pathways may contribute to host defense vs. Brucella in aged mice.

Food Safety Guidance for Older Adults

Aging is associated with loss of the physical barriers and immune efficiency that typically control pathogens' access to and multiplication within the body, thus making infection more likely in elderly persons. Chronic diseases and other health factors, such as malnutrition and immobility, may increase susceptibility to and severity of infections, including foodborne illnesses, in elderly persons, as well as associated morbidity and mortality. Prevention is the best way to avoid foodborne illnesses, but older adults have long-established food preparation and handling practices, some of which may increase the likelihood of illness. Elderly persons rely on physicians as trusted sources of health information. Physicians and other health care professionals can help prevent and control foodborne diseases by educating their patients about the risks of foodborne illness, providing sound advice on safe food-handling and consumption practices, making rapid appropriate diagnoses, and reporting cases promptly to public health authorities.

Malnutrition and energy restriction differentially affect viral immunity

Protein-energy malnutrition is associated with a decrease in immunity and an increase in infectious disease. Both of these effects are exacerbated in aging. Conversely, energy restriction (ER) without malnutrition extends the lifespan in animals and retards the age-related decline in various parameters of immune function. Recent evidence suggests, however, that aged ER mice exhibit an increased mortality in response to primary influenza infection compared with age-matched controls. Underweight may contribute to this outcome due to an inability to meet the energy demands associated with the immune response to primary viral infection. The energetic costs of immune responsiveness must be considered in the undernourished aging population and emerging studies of ER in humans.

Microcebus murinus: a useful primate model for human cerebral aging and Alzheimer's disease?

Age-associated dementia, in particular Alzheimer's disease (AD), will be a major concern of the 21st century. Research into normal brain aging and AD will therefore become increasingly important. As for other areas of medicine, the availability of good animal models will be a limiting factor for progress. Given the complexity of the human brain, the identification of appropriate primate models will be essential to further knowledge of the disease. In this review, we describe the features of brain aging and age-associated neurodegeneration in a small lemurian primate, the Microcebus murinus, also referred to as the mouse lemur. The mouse lemur has a relatively short life expectancy, and animals over 5 years of age are considered to be elderly. Among elderly mouse lemurs, the majority show normal brain aging, whereas approximately 20% develop neurodegeneration. This Microcebus age-associated neurodegeneration is characterized by a massive brain atrophy, abundant amyloid plaques, a cytoskeletal Tau pathology and a loss of cholinergic neurons. While elderly mouse lemurs with normal brain aging maintain memory function and social interaction, animals with age-associated neurodegeneration lose their cognitive and social capacities and demonstrate certain similarities with age-associated human AD. We conclude that M. murinus is an interesting primate model for the study of normal brain aging and the biochemical dysfunctions occurring in age-associated neurodegeneration. Mouse lemurs might also become an increasingly important model for the development of novel treatments in this domain.

Analysis of interaction of cloned human and/or sheep fetal hemoglobin γ-chain and LPS in augmenting induction of inflammatory cytokine production in vivo and in vitro

We have reported earlier that purified preparations of sheep fetal hemoglobin, but not adult hemoglobin, in concert with non-stimulatory doses of lipopolysaccharide (LPS) (lipid A), act cooperatively to regulate in vitro production of a number of cytokines, including TNFalpha, TGFbeta and IL-6 from murine and human leukocytes. Following in vivo treatment of mice with the same combination of hemoglobin and LPS, harvested spleen or peritoneal cells showed a similar augmented capacity to release these cytokines into culture supernatants. We report below that genetically cloned gamma-chain of human or sheep fetal hemoglobin, but not cloned alpha- or beta-chains, can produce this cooperative effect, as indeed can HPLC purified, heme-free, gamma-chains derived from cord blood fetal hemoglobin, and that purified haptoglobin completely abolishes the cooperative interaction.