Highly variable upper and abyssal overturning cells in the South Atlantic.

The Meridional Overturning Circulation (MOC) is a primary mechanism driving oceanic heat redistribution on Earth, thereby affecting Earth's climate and weather. However, the full-depth structure and variability of the MOC are still poorly understood, particularly in the South Atlantic. This study presents unique multiyear records of the oceanic volume transport of both the upper (<~3100 meters) and abyssal (>~3100 meters) overturning cells based on daily moored measurements in the South Atlantic at 34.5°S. The vertical structure of the time-mean flows is consistent with the limited historical observations. Both the upper and abyssal cells exhibit a high degree of variability relative to the temporal means at time scales, ranging from a few days to a few weeks. Observed variations in the abyssal flow appear to be largely independent of the flow in the overlying upper cell. No meaningful trends are detected in either cell.

Frailty from an Oral Health Point of View.

Frailty commonly affects older persons, increasing their risk for adverse outcomes. Oral health is affected by those conditions related to the mouth and teeth, including caries, periodontal diseases, dysgeusia, presbyphagia and oral cancer among others. Oral health problems can be classified as development defects and acquired problems. These latter are related to infection or trauma, have a cumulative effect throughout life and their consequences are lifelong. Such acquired problems can be classified as primary or secondary, both interacting in a complex manner. Recovery to a previous state of tissue integrity is often impossible from these conditions. These complex interactions have negative impacts on the individual's general health and quality of life. Oral status is an important contributor to general health, and has been linked to several chronic conditions such as cognitive impairment, diabetes, cardiovascular diseases, strokes, and cancer. An individual's oral health is mostly stable throughout life. Tooth loss may be considered as the final outcome, resulting as a consequence of history of caries and periodontitis, as well as failure of prevention and treatment. The loss of a tooth may thus represent the first step of a vicious cycle. In fact, without intervention, one missing tooth may lead to further teeth loss, thus reducing the capability to chew and consume nutrients (essential for life and adequate physiological function), and finally contributing to the development of age-related chronic diseases.

The Coyoacán Cohort Study: Design, Methodology, and Participants' Characteristics of a Mexican Study on Nutritional and Psychosocial Markers of Frailty.

BACKGROUND: "Frailty" has emerged as a condition associated with an increased risk of functional decline among the elderly, which may be differentiated from aging, disability, and co-morbidities. OBJECTIVE: The Mexican Study of Nutritional and Psychosocial Markers of Frailty among Community-Dwelling Elderly has emerged to help answer many questions about frailty among the older adults. This report presents the design of the study and baseline data of its participants. DESIGN: The "Coyoacan cohort" is a longitudinal observational study developed in Mexico City. PARTICIPANTS: A representative sample of 1,294 non-institutionalized men and women aged 70 years and older were randomly recruited to undergo a face-to-face interview and a comprehensive geriatric assessment (including clinical evaluations and blood samples) between 2008 and 2009. MEASUREMENTS: Data collected included socio-demographic and economic characteristics, medical history, oral health, drug use, cognitive function and mood, nutritional status, physical performance and functional status, physical activity, quality of life, social networks, and biological data. Frailty was defined as the presence of ≥3 of the following components: slowness, poor muscle strength, low physical activity, exhaustion and unintentional weight loss. RESULTS: A total of 1,124 participants completed the interview. The mean age was 79.5 ± 7.1 years, and 55.9% were female. Nine hundred and forty-five subjects completed the clinical evaluation and 743 blood samples were collected. The baseline prevalence of frailty was 14.1%. CONCLUSIONS: Understanding the medical, biological, and environmental factors that contribute to the phenomenon of frailty is the goal of the current research in the field.

Association between the Use of Complete Dentures and Frailty in Edentulous Mexican Elders.

OBJECTIVES: Edentulism and use of complete dentures (CD), which are common among elderly people, increase the risk for malnutrition and weight loss, components of frailty syndrome. OBJECTIVES: To identify if CD use is associated with the presence of frailty in a group of edentulous people aged ≥70 years, residing in Mexico City. DESIGN: This was a cross-sectional analysis of baseline data of a cohort study. SETTING AND PARTICIPANTS: The study population consisted of 33,347 people living independently in one district of Mexico City, 149 edentulous subjects were interviewed and examined for this analysis. MEASUREMENTS: Frail people experienced 3 or more of the following 5 components: unintentional weight loss, poor endurance and energy, low physical activity, slowness, and weakness. Dental variables were CD use, CD functionality, self-perception of oral health, use of dental services the previous year, xerostomia, and chewing problems. Age, sex, education level, cognitive impairment, urinary incontinence, number of falls, hospitalization, and number of drugs consumed were considered. Univariate analysis and a logistic regression model were used. RESULTS: The prevalence of frailty was 23.5%. The probability of being frail increased among participants with osteoporosis (OR = 3.2), urinary incontinence (OR = 3.8), cognitive impairment (OR = 4.1), and non-use of CD (OR = 5.2); for each additional drug taken per day, the risk of frailty increased by 28.9%. CONCLUSIONS: The non-use of CD in edentulous older persons can be a risk marker for frailty, health evaluation of the elderly should include a dental assessment.

[Annual follow-up of the gastrointestinal parasitosis of white-tailed deer Odocoileus virginianus (Artiodactyla: Cervidae) in captivity in Yucatán, México]. / Seguimiento anual de la parasitosis gastrointestinal de venados cola blanca Odocoileus virginianus (Artiodactyla: Cervidae) en cautiverio en Yucatán, México.

Gastrointestinal parasites, and egg and oocyst output in the faeces of captive white-tailed deer (Odocoileus virginianus yucatanensis) were recorded in Yucatan, Mexico. Feces were obtained from from January through December 1995 (ten samples every two weeks per place). Samples were processed by flotation and the McMaster techniques. Faecal cultures for L3 larvae were made by the Corticelli-Lai technique. Oocysts in faeces were cultured in 2% potassium dicromate. Seven genera were determined (Haemonchus spp., Cooperia spp, Isospora spp., Eimeria spp., Trichuris spp., Strongyloides spp. and Moniezia spp.) which represent five orders. The most frequent genera were Haemonchus, Isospora and Eimeria. The genus Isospora is reported for the first time in deer of this region, although it was not possible to explain the source of this parasite. The frequency and level of faecal egg and oocyst outputs were variable during the year and increased during the rainy season. There was a positive correlation between relative humidity, environmental temperature and rainfall with the coccidia and strongylida orders. In the central zone of Yucatan the meteorological conditions during the rainy season are favourable for the development of gastrointestinal parasitism which enable an increased risk of infection for deer.

Carbon dioxide assimilation by Thiobacillus novellus under nutrient-limited mixotrophic conditions.

The contribution of CO2 to cell material synthesis in Thiobacillus novellus under nutrient-limited conditions was estimated by comparing 14CO2 uptake rates of steady-state autotrophic cultures with that of heterotrophic and mixotrophic cultures at a given dilution rate. Under heterotrophic conditions, some 13% of the cell carbon was derived from CO2; this is similar to the usual anaplerotic CO2 fixation in batch cultures of heterotrophic bacteria. Under mixotrophic conditions, the contribution of CO2 to cell material synthesis increased with increasing S2O3 2- -to-glucose ratio in the medium inflow; at a ratio of 10, ca. 32% of the cell carbon was synthesized from CO2. We speculate that the use of CO2 as carbon source, even when the glucose provided is sufficient to fulfill the biosynthetic needs, may augment the growth rate of the bacterium under such nutrient-limited conditions and could therefore be of survival value in nature. Some of the CO2 assimilated was excreted into the medium as organic compounds under all growth conditions, but in large amounts only in autotrophic environments as very low dilution rates.

Growth of Thiobacillus novellus on mixed substrates (mixotrophic growth).

In a mixotrophic environment, Thiobacillus novellus concurrently utilized glucose and thiosulfate but showed no stimulation of growth rate or yield. In most mixotrophic environments examined, the growth rate was lower than the heterotrophic growth rate, the extent of the decrease depending on the concentration and relative proportion of thiosulfate and glucose in the medium. Both thiosulfate and glucose were degraded to their most oxidized products in mixotrophic medium, yet the biomass production in this medium was comparable to that found in heterotrophic medium containing glucose alone at the corresponding concentration. It was postulated that in mixotrophic medium the oxidation of thiosulfate, glucose, or partially that of both was uncoupled from energy generation. These results differ in many respects from those reported earlier by LeJohn et al. (J. Bacteriol. 94: 1484--1491, 1967); experiments designed to exactly duplicate some of the growth conditions employed by these workers did not resolve the discrepancy.

Regulation of glucose transport and metabolism in Thiobacillus novellus.

To investigate the physiological basis of decreased rate of glucose utilization by Thiobacillus novellus in a mixotrophic environment (R. C. Perez and A. Matin, J. Bacteriol. 142:633-638, 1980), its glucose transport system was characterized and the modulation of this system as well as enzymes of glucose metabolism by the growth environment was examined. Uptake of 2-deoxy-d-glucose by cell suspensions was almost abolished by respiratory chain inhibitors, and the sugar accumulated unchanged inside the cells against a concentration gradient: its transport is probably linked to the proton electrochemical gradient. The glucose transport system, as well as several enzymes of glucose metabolism, had a high specific activity in heterotrophic cells, intermediate activity in mixotrophic cells, and low activity in autotrophic cells; thus, they are induced by glucose but repressed by thiosulfate, its metabolites, or both. Thiosulfate and sulfite inhibited the glucose transport system uncompetitively and noncompetitively, respectively (apparent K(i) = 3.1 x 10(-2) M and 3.3 x 10(-7) M, respectively) and also inhibited glucose-6-phosphate dehydrogenase activity. Thus, the rate of glucose utilization in mixotrophic environments decreased because thiosulfate and its metabolites repress as well as inhibit the glucose transport system and enzymes of glucose metabolism. The significance of this and other regulatory phenomena that come into play in such environments is discussed.