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Metabolism of dietary ODAP in humans may be responsible for the low incidence of neurolathyrism.

OBJECTIVES: The reasons for the very low incidence of the disease neurolathyrism in humans even after excessive consumption of the pulse, Lathyrus sativus, under severe drought and famine conditions, and its continued consumption by large populations during normal periods without any deleterious effects have been examined in the context of a possible metabolism or detoxification of beta-N-oxalyl-L-alpha, beta-diaminopropionic acid (ODAP), the major neurotoxic amino acid of L. sativus. DESIGN AND METHODS: ODAP in urine samples from 54 subjects habitually consuming the pulse and in three volunteers on an L. sativus diet was determined by the OPT method following clean up of the samples on an alumina column. Urinary oxalate was also determined in these individuals. RESULTS: Twenty-five subjects showed no excretion of ODAP and it was only less than 0.7% of the dietary intake in the remaining 29 subjects. Urinary excretion of ODAP in three volunteers was also less than 1% with a peak excretion in the 4-h sample. The 4-h blood sample from one volunteer had a maximum ODAP concentration of 177 microM. The urinary oxalate content in the volunteers was nearly 3-fold higher compared to controls. CONCLUSIONS: The low excretion of dietary ingested ODAP in humans is in sharp contrast to that seen in animals and indicates a metabolism or detoxification of ODAP which may be unique to humans and may explain the low incidence of neurolathyrism.

Amino Acids, Diamino↗

Generating high-yielding varieties by genetic manipulation of plant architecture.

Despite a huge population increase since the 1960s, the green revolution more than doubled world grain production and averted large-scale famine. Food crop productivity will have to be further raised, however, because the world population is still increasing rapidly. Among several parameters associated with the increase in yield potential, genes that control plant height and tiller number (in cereal crops) have recently been identified. In addition, a promising strategy to generate semi-dwarf varieties has been developed. Recent advances in plant genome analyses and plant biotechnology will realize a second green revolution through the genetic engineering of food crops.

Agriculture↗

The abandonment of antibacterials: why and wherefore?

The pharmaceutical industry is currently abandoning its antibacterial discovery research efforts. This seems to be part of a cyclical pattern in this therapeutic area. The reasons behind these ongoing cycles of feast and famine are multiple, but most revolve around the perception of market opportunities from the continuing emergence of resistance, balanced against the difficulties in the discovery of novel antibacterial compounds, the costs of development and the general regulatory and financial environment in which companies find themselves. Relief for the industry will require both regulatory and legislative action at a time when this will be politically difficult to achieve. In the meantime, the problems of antimicrobial resistance are not going away.

Anti-Bacterial Agents↗

Reduced dopaminergic tone in hypothalamic neural circuits: expression of a "thrifty" genotype underlying the metabolic syndrome?

The thrifty genotype hypothesis postulates that the genetically determined ability to grow obese and insulin resistant in times of food abundance confers a survival advantage in times of famine. Obviously, this ability poses a major health threat in modern times, where food is always available in large quantities. In the last 10-15 years, many genes encoding pathways that orchestrate energy balance and fuel flux have been discovered. This paper summarizes the evidence that diminished dopaminergic tone in hypothalamic nuclei contributes to the "thrifty" genotype/phenotype. Reduced dopaminergic neurotransmission in the suprachiasmatic nucleus of seasonally obese animals appears to drive noradrenalin and NPY mediated transmissions in other nuclei to induce the obesity syndrome at the appropriate time of year. Treatment with dopamine D(2) receptor agonists can fully reverse the metabolic syndrome in these animals. Similar mechanisms are operative in non-seasonal obese animal models. In man, treatment with dopamine D(2) receptor antagonists induces obesity and type 2 diabetes mellitus, whereas dopamine D(2) receptor activation ameliorates the metabolic profile in obese nondiabetic and diabetic humans. Various loss of function mutations of the dopamine D(2) receptor gene are associated with overweight in humans. In concert, the data support the notion that diminution of dopaminergic (dopamine D(2) receptor mediated) transmission in relevant hypothalamic nuclei sets the stage for efficient partitioning of ingested nutrients to contribute to a phenotype that is not so thrifty anymore.

Animals↗

A proposed model of fat packaging by exchangeable lipid droplet proteins.

Humans have evolved mechanisms of efficient fat storage to survive famine, but these mechanisms contribute to obesity in our current environment of plentiful food and reduced activity. Little is known about how animals package fat within cells. Five related structural proteins serve roles in packaging fat into lipid droplets. The proteins TIP47, S3-12, and OXPAT/MLDP/PAT-1 move from the cytosol to coat nascent lipid droplets during rapid fat storage. In contrast, perilipin and adipophilin constitutively associate with lipid droplets and play roles in sustained fat storage and regulation of lipolysis. Different tissues express different complements of these lipid droplet proteins. Thus, the tissue-specific complement of these proteins determines how tissues manage lipid stores.

Adipose Tissue↗

When half of the population died: the epidemic of hemorrhagic fevers of 1576 in Mexico.

During the 16th century, Mexico suffered a demographic catastrophe with few parallels in world's history. In 1519, the year of the arrival of the Spaniards, the population in Mexico was estimated to be between 15 and 30 million inhabitants. Eighty-one years later, in 1600, only two million remained. Epidemics (smallpox, measles, mumps), together with war, and famine have been considered to be the main causes of this enormous population loss. However, re-evaluation of historical data suggests that approximately 60-70% of the death toll was caused by a series of epidemics of hemorrhagic fevers of unknown origin. In order to estimate the impact of the 1576 epidemic of hemorrhagic fevers on the population we analyzed the historical record and data from the 1570 and 1580 censuses of 157 districts. The results identified several remarkable aspects of this epidemic: First, overall, the population loss for these 157 districts was 51.36%. Second, there was a clear ethnic preference of the disease, the Spanish population was minimally affected whereas native population had high mortality rate. Third, the outbreak originated in the valleys of central Mexico whence it evolved as an expansive wave. Fourth, a positive correlation between altitude and mortality in central Mexico was found. Fifth, a specific climatic sequence of events was associated with the initiation and dissemination of the hemorrhagic fevers. Although the last epidemic of hemorrhagic fevers in Mexico ended in 1815, many questions remain to be answered. Perhaps the most relevant ones are whether there is a possible reemergence of the hemorrhagic fevers and how vulnerable we are to the disease.

Disease Outbreaks↗

Degradation of chlorpyrifos contaminated soil by bioslurry reactor operated in sequencing batch mode: bioprocess monitoring.

Bioslurry reactor (SS-SBR) was studied for the degradation of chlorpyrifos contaminated soil using native mixed microflora, by adopting sequencing batch mode (anoxic-aerobic-anoxic) operation. Reactor operation was monitored for a total cycle period of 72 h consisting of 3 h of FILL, 64 h REACT, 2 h of SETTLE, and 3 h of DECANT with chlorpyrifos concentrations of 3000 micrpg/g, 6000 microg/g and 12000 microg/g. At 3000 microg/g of chlorpyrifos concentration, 91% was degraded after 72 h of the cycle period, whereas in the case of 6000 microg/g of chlorpyrifos, 82.5% was degraded. However, for 12000 microg/g of chlorpyrifos, only 14.5% degradation was observed. The degradation rate was rapid at lower substrate concentration and 12000 microg/g of substrate concentration was found to be inhibitory. Chlorpyrifos removal rate was slow during the initial phase of the sequence operation. Half-life of chlorpyrifos degradation (t0.5) was estimated to be 6.3 h for 3000 microg/g of substrate, 17.5 h for 6000 microg/g and 732.2 h for 12000 microg/g. Process performance was assessed by monitoring chlorpyrifos concentration and biochemical process parameters viz., pH, oxidation and reduction potential (ORP), dissolved oxygen (DO), oxygen consumption rate (OCR) and microbial count (CFU) during sequence operation. From the experimental data obtained it can be concluded that the rate-limiting step with the bioslurry phase reactor in the process of chlorpyrifos degradation may be attributed to the concentration of substrate present in either soil or liquid phase. Periodic operations (SBR) by varying individual components of substrate with time in each process step place micro-organisms under nutritional changes from feast to famine and maintains a wide distribution in the population of micro-organisms resulting in high uptake of the substrate in the bioslurry reactor.

Bacteria, Aerobic↗

Food restriction, evolution and ageing.

The food restriction model for life extension is nearing "three-score and 10" years of age and remains in good shape, preserving much of the mystique of its youth. Although originally described for laboratory rodents, recent work shows that food restriction also appears to slow ageing processes in a range of other animal species, raising the question of whether this response represents some generalised evolutionary adaptation, perhaps a strategy to cope with periods of famine. If the food restriction response does have an adaptive basis, this would suggest that specific gene regulatory processes have evolved to shape the organism's physiological response to food restriction. It will then be important to investigate how these are organised and whether the same or different factors are at play in the various species in which food restriction extends life span.

Aging↗

Changes in reproductive indices in Chuvashian women whose maturation was during World War II.

OBJECTIVES: The aim of the present study was to evaluate whether Chuvashian women whose maturation was during World War II and the subsequent rehabilitation period were different from women born at other times in terms of age at menarche and age at menopause. DESIGN: The cohort included 745 Chuvashian females aged 18-90 years; age at menarche (N=653), ranged from 10 to 24 years (mean 15.42+/-2.11). Data regarding menopausal age was obtained from 322 females born between 1915 and 1950 (mean 48.5+/-4.6). We computed descriptive statistics of the age of menopause and the age of menarche for different birth cohorts; we compared the mean values by Student's t-test and the variances by F-test. RESULTS: The "expected" maturation period of women whose age at menarche >20 and most women whose age at menopause < or =38 was between 1939 and 1950. Women whose age at menarche >20 showed normal parameters regarding age at menopause, and women whose age at menopause was < or =38 showed normal parameters of age at menarche. The variances of age at menopause in women born from 1925 to 1936 was almost two-fold higher than in women born earlier and afterwards (p=0.0003). The difference in the mean ages was significant for both menarche (p=0.005) and menopause (p=0.001). CONCLUSION: Periods of socioeconomic disasters such as war and famine can influence women's age at menarche and age at menopause. Women, whose maturation occurred during or immediately after World War II, showed a higher mean age at menarche and a wider dispersion of age at menopause than other women.

Adolescent↗

Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both?

European researchers have observed that schizophrenia is 3 times more frequent in immigrants than in native-born subjects. This increased risk is even higher in dark-skinned immigrants, and the second generation is more affected than the first one. Immigrant status is an important environmental risk factor not only for schizophrenia but also for other psychoses. The explanations proposed to date have been mainly related to epidemiological biases and psychological reasons, such as racism or social defeat, but no biological hypotheses have been tested so far. This article proposes two biological hypotheses related to changes in sun exposure, changes in diet, and stress associated with immigration, which would explain the increased risk for psychosis associated with immigrant status. (1) Vitamin D insufficiency has been proposed as a risk factor for schizophrenia. The main source of vitamin D is through photosynthesis by sun exposure, and dark skins need more sun exposure to maintain adequate blood levels. Vitamin D insufficiency in adulthood could explain why dark-skinned immigrants develop psychosis when moving to high latitude countries, and its insufficiency during pregnancy could explain why the observed risk is higher in the second generation. (2) The second hypothesis is that of epigenetics, with psychosis resulting from modifications in gene expression caused by changes in diet and/or stress related to immigration. The role of homocysteine and the vitamin B-complex, especially folic acid, in these changes in DNA transcription would vary according to the polymorphism of the methylenetetrahydrofolate reductase gene. The vitamin D insufficiency and epigenetics hypotheses are consistent with yet unexplained findings well known in the epidemiology of schizophrenia, such as the increased risk in the urban environment, the excess of winter births, the excess of schizophrenia births after maternal famine, and the shorter interbirth period before a schizophrenia birth. In order to test these hypotheses, epidemiological studies of psychosis and immigration should include objective measures of skin color, which is predicted to be a more important risk factor than ethnicity. They should measure vitamin D, homocysteine and vitamin B-complex status and assess the polymorphisms of the vitamin D receptors and the methylenetetrahydrofolate reductase gene. If confirmed, these hypotheses would lead to effective and inexpensive preventive measures which would markedly decrease the rates of psychosis and schizophrenia, as well as the burden and stigma of these diseases, and greatly improve the mental health of immigrants.

Emigration and Immigration↗

Parvovirus B19 infection of brain: possible role of gender in determining mental illness and autoimmune thyroid disorders.

Major theories about the etiologies of chronic mental illnesses such as bipolar disorder and schizophrenia include genetic and environmental factors such as famine and infection. It is likely that multiple genes play a role in the pathogenesis of these disorders, but no single gene has been identified as causative. Several viruses have been investigated as potential candidates, but conflicting reports exist. Although a relationship between bipolar disorder and schizophrenia with autoimmune disorders has also been documented for many years, reports are often conflicting. We hypothesize that parvovirus B19 (B19), a common human pathogen, due to its ability to infect the brain and induce autoimmunity, is a strong candidate that may unite prevailing theories. In particular, our preliminary data suggest that B19 may be most likely involved in co-morbid bipolar and autoimmune thyroid disorders in females. In schizophrenics, the gender trend may be reversed. We propose that there is a complex interaction between immuno-genetics, autoimmunity, gender, and B19 infection that leads to at least some forms of bipolar disorder and schizophrenia. Future studies that investigate this hypothesis are warranted and outlined.

Adult↗

Adaptive thermogenesis and uncoupling proteins: a reappraisal of their roles in fat metabolism and energy balance.

After decades of controversies about the quantitative importance of autoregulatory adjustments in energy expenditure in weight regulation, there is now increasing recognition that even subtle variations in thermogenesis could, in dynamic systems and over the long term, be important in determining weight maintenance in some and obesity in others. The main challenge nowadays is to provide a mechanistic explanation for the role of adaptive thermogenesis in attenuating and correcting deviations of body weight and body composition, and in the identification of molecular mechanisms that constitute its effector systems. This workshop paper reconsiders what constitutes adaptive changes in thermogenesis and reassesses the role of the sympathetic nervous system (SNS) and uncoupling proteins (UCP1, UCP2, UCP3, UCP5/BMCP1) as the efferent and effector components of the classical one-control system for adaptive thermogenesis and fat oxidation. It then reviews the evidence suggesting that there are in fact two distinct control systems for adaptive thermogenesis, the biological significance of which is to satisfy--in a lifestyle of famine-and-feast--the needs to suppress thermogenesis for energy conservation during weight loss and weight recovery even under environmental stresses (e.g., cold, infection, nutrient imbalance) when sympathetic activation of thermogenesis has equally important survival value.

Adaptation, Physiological↗

Early influences on human energy regulation: thrifty genotypes and thrifty phenotypes.

Early influences on human ingestive behavior and other aspects of energy homeostasis can be defined according to two very different time scales: the evolutionary time frame responsible for selection of behavioral and metabolic traits embedded within the genome; and the life-course time frame responsible for setting the phenotype. Evolutionary influences: Famine has been a constant threat to human survival leading to the selection of thrifty genes. Thriftiness can take many forms: metabolic (an 'energy-sparing' super-efficient metabolism); adipogenic (a propensity to rapid fat gain); physiologic (an ability to switch off non-essential processes); gluttony (a tendency to gorge when food is available); sloth (a tendency to conserve energy through inactivity); or behavioral (hoarding, meanness, theft, etc). Life-course influences: The nutritional environment of the early embryo can have a major impact on its survival, and its immediate and later physiology. Subsequently, the fetus is sensitive to its nutrient supply that in turn is affected by maternal fuel supply and by the constraints of the utero-placental unit. Adaptive plasticity also continues through infancy. Ingestive behavior in terms of appetite and satiety could theoretically be affected by some of these metabolic adaptations. This paper will describe the key elements of the thrifty genotype and phenotype and review the evidence base relating these early effects to differences in ingestive behavior.

Animals↗

Corticostriatal-hypothalamic circuitry and food motivation: integration of energy, action and reward.

Work over the past decade has supported the idea that discrete aspects of appetitive motivation are differentially mediated by separate but interacting neurochemical systems within the nucleus accumbens (Acb). We review herein a series of studies in rats comparing the effects of manipulating Acb amino acid, opioid, acetylcholine, and dopamine systems on tests of free-feeding and food-reinforced operant responding. Results from our laboratory and in the literature support three general conclusions: (1) GABA output neurons localized exclusively within the Acb shell directly influence hypothalamic effector mechanisms for feeding motor patterns, but do not participate in the execution of more complex food-seeking strategies; (2) enkephalinergic neurons distributed throughout the Acb and caudate-putamen mediate the hedonic impact of palatable (high sugar/fat) foods, and these neurons are under modulatory control by striatal cholinergic interneurons; and (3) dopamine transmission in the Acb governs general motoric and arousal processes related to response selection and invigoration, as well as motor learning-related plasticity. These dissociations may reflect the manner in which these neurochemical systems differentially access pallido-thalamo-cortical loops reaching the voluntary motor system (in the case of opioids and dopamine), versus more restricted efferent connections to hypothalamic motor/autonomic control columns (in the case of Acb shell GABA and glutamate systems). Moreover, we hypothesize that while these systems work in tandem to coordinate the anticipatory and consummatory phases of feeding with hypothalamic energy-sensing substrates, the striatal opioid network evolved a specialized capacity to promote overeating of energy-dense foods beyond acute homeostatic needs, to ensure an energy reserve for potential future famine.

Acetylcholine↗

Purification of an isoform of patatin with antimicrobial activity against Phytophthora infestans.

Phytophthora infestans (Mont.) de Bary is infamous as the causal agent of the late blight epidemic contributing to the Irish potato famine of the mid 19th century and remains agriculture's most destructive disease as new mutations and migrations confound control measures. In efforts to develop resistant varieties, a somatic hybrid (the Wisconsin J series) between potato (Solanum tuberosum) and a wild relative (Solanum bulbocastanum) has been found to convey durable resistance against the pathogen. We screened the total protein (100 microg ml(-1)) of somatic hybrid varieties J138, J138A12, J101K12, J103K12, and J101K9 for in vitro spore germination inhibition of P. infestans. Since J138 exhibited maximum inhibition at 150 microg ml(-1) in comparison to other varieties, we purified a 40 kD protein from J138 tubers by assaying its ability to inhibit spore germination in P. infestans spores. The highly purified protein was able to inhibit P. infestans spore germination by 70% at the 2.5 microg ml(-1) concentration. The N-terminal sequence of this protein was found to have exact amino acid homology to patatin, the major storage protein of potato tubers. The inhibitory protein has the same molecular weight as patatin and cross-reacts with patatin antibodies. The infection of J138 plants with spores of P. infestans under greenhouse conditions showed that patatin is expressed in stem tissue 72 h after the plant is inoculated with field isolates of P. infestans (US8). In this communication, we report the purification, characterization and antifungal activity against spores of P. infestans of patatin-J from potato tubers.

Anti-Infective Agents↗

Psychoneuroendocrinology of anorexia nervosa.

It is suggested that the symptoms of anorexia nervosa are physiological responses to starvation. There is no evidence of a neural or non-neural dysfunction that predisposes women for anorexia nervosa and the endocrine and psychological consequences of starvation are reversed once patients have re-learnt how to eat and regained a normal body weight. Because variability in the supply of food may be a common evolutionary condition, it is more likely that body weight is variable than constant in normal circumstances. The role of the neuroendocrine system in times of feast and famine is to allow the individual to adopt behavioral strategies as needed rather than maintaining body weight homeostasis. Treatment of anorexic patients should aim at reducing their high level of physical activity in order to facilitate eating.

Anorexia Nervosa↗

The disease profile of poverty: morbidity and mortality in northern Uganda in the context of war, population displacement and HIV/AIDS.

The population of Gulu District (northern Uganda) has been severely incapacitated by war, epidemics and social disruption. This study is aimed at describing disease patterns and trends in this area through a retrospective analysis of discharge records for 155205 in-patients of Lacor Hospital in the period 1992-2002. The burden of infectious diseases in childhood is overwhelming, with malaria accounting for the steepest increase in admissions. Admissions for war-related injuries and malnutrition fluctuated with the intensity of the war and the severity of famine. Emerging and re-emerging infections, such as HIV/AIDS, tuberculosis and Ebola, accounted for a heavy disease burden; however, there has been a trend for admissions related to HIV/AIDS and tuberculosis to decrease since the implementation of community-based services. Vulnerable groups (infants, children and women) accounted for 79.8% of admissions. Long-term war, population displacement, the collapse of social structures and the breakdown of the health system place people at a much greater risk of persistent, emerging and re-emerging infectious diseases, malnutrition and war-related injuries, shaping the 'disease profile of poverty'. Most of the disease burden results from infectious diseases of childhood, whose occurrence could be dramatically reduced by low-cost and effective preventive and curative interventions.

Acquired Immunodeficiency Syndrome↗

Schizophrenia and impaired homocysteine metabolism: a possible association.

BACKGROUND: An increased risk of both schizophrenia and neural tube defects was observed in a birth cohort exposed to famine during early gestation. Neural tube defects have been related to a folate-sensitive genetic defect in homocysteine metabolism. If this were also true for schizophrenia, then cases with low folate (LF)--and only these cases--should have increased homocysteine levels compared with controls. METHODS: We compared homocysteine levels of schizophrenia cases and normal controls with low folate (LF) and without low folate (non-LF). Low folate was defined by the bottom tertile for controls. RESULTS: In the LF group (6 cases, 8 controls), mean homocysteine was 10.7 microM in cases compared with 7.7 microM in controls (p = .03). In the non-LF group (11 cases, 16 controls) mean homocysteine did not differ for cases and controls. CONCLUSIONS: These pilot data are compatible with the hypothesis that a folate-sensitive defect in homocysteine metabolism contributes to cases of schizophrenia.

Adult↗