EFFECT OF WATER AVAILABILITY ON SOIL MICROBIAL BIOMASS IN SECONDARY FOREST IN EASTERN AMAZONIA

Soil microbial biomass (SMB) plays an important role in nutrient cycling in agroecosystems, and is limited by several factors, such as soil water availability. This study assessed the effects of soil water availability on microbial biomass and its variation over time in the Latossolo Amarelo concrecionário of a secondary forest in eastern Amazonia. The fumigation-extraction method was used to estimate the soil microbial biomass carbon and nitrogen content (SMBC and SMBN). An adaptation of the fumigation-incubation method was used to determine basal respiration (CO2-SMB). The metabolic quotient (qCO2) and ratio of microbial carbon:organic carbon (CMIC:CORG) were calculated based on those results. Soil moisture was generally significantly lower during the dry season and in the control plots. Irrigation raised soil moisture to levels close to those observed during the rainy season, but had no significant effect on SMB. The variables did not vary on a seasonal basis, except for the microbial C/N ratio that suggested the occurrence of seasonal shifts in the structure of the microbial community.

SOIL QUALITY IN RELATION TO FOREST CONVERSION TO PERENNIAL OR ANNUAL CROPPING IN SOUTHERN BRAZIL

Many forested areas have been converted to intensive agricultural use to satisfy food, fiber, and forage production for a growing world population. There is great interest in evaluating forest conversion to cultivated land because this conversion adversely affects several soil properties. We examined soil microbial, physical, and chemical properties in an Oxisol (Latossolo Vermelho distrófico) of southern Brazil 24 years after forest conversion to a perennial crop with coffee or annual grain crops (maize and soybeans) in conventional tillage or no-tillage. One goal was to determine which soil quality parameters seemed most sensitive to change. A second goal was to test the hypothesis that no-tillage optimized preservation of soil quality indicators in annual cropping systems on converted land. Land use significantly affected microbial biomass and its activity, C and N mineralization, and aggregate stability by depth. Cultivated sites had lower microbial biomass and mineralizable C and N than a forest used as control. The forest and no-tillage sites had higher microbial biomass and mineralizable C and N than the conventional tillage site, and the metabolic quotient was 65 and 43 % lower, respectively. Multivariate analysis of soil microbial properties showed a clear separation among treatments, displaying a gradient from conventional tillage to forest. Although the soil at the coffee site was less disturbed and had a high organic C content, the microbial activity was low, probably due to greater soil acidity and Al toxicity. Under annual cropping, microbial activity in no-tillage was double that of the conventional tillage management. The greater microbial activity in forest and no-tillage sites may be attributed, at least partially, to lower soil disturbance. Reducing soil disturbance is important for soil C sequestration and microbial activity, although control of soil pH and Al toxicity are also essential to maintain the soil microbial activity high.

Chemical and Biochemical Properties of Oxisols after Sewage Sludge Application for 16 Years

ABSTRACT The large production of sewage sludge (SS), especially in large urban centers, has led to the suggestion of using this waste as fertilizer in agriculture. The economic viability of this action is great and contributes to improve the environment by cycling the nutrients present in this waste, including high contents of organic matter and plant nutrients. This study evaluated the chemical and biochemical properties of Dystrophic and EutroferricLatossolos Vermelhos (Oxisols) under corn and after SS application at different rates for 16 years. The field experiment was carried out in Jaboticabal, São Paulo State, Brazil, using a randomized block design with four treatments and five replications. Treatments consisted of control - T1 (mineral fertilization, without SS application), 5 Mg ha-1 SS - T2, 10 Mg ha-1 SS - T3, and 20 Mg ha-1 SS - T4 (dry weight base). The data were submitted to variance analysis and means were compared by the Duncan test at 5 %. Sewage sludge increased P extracted by resin in both theLatossolos Vermelhos, Dystrophic and Eutroferric, and the organic matter content in the Dystrophic Latossolo Vermelho. The waste at the rate 20 Mg ha-1 on a dry weight basis promoted increases in acid phosphatase activity in Eutroferric Latossolo Vermelho, basal respiration and metabolic quotient in DystrophicLatossolo Vermelho. The rate 20 Mg ha-1 sewage sludge on a dry weight basis did not alter the soil microbial biomass in both the Latossolos Vermelhos; in addition, it improved corn yields without inducing any symptoms of phytotoxicity or nutrient deficiency in the plants.

Inhibition of Na(+)-K(+)-ATPase by digoxin and its relation with energy expenditure and nutrient oxidation rate.

This study investigates the effects of digoxin, an inhibitor of the Na+ pump (Na(+)-K(+)-ATPase), on resting metabolic rate (RMR), respiratory quotient (RQ), and nutrient oxidation rate. Twelve healthy male subjects followed a double-blind protocol design and received either 1 mg/day digoxin or a placebo 2 days before indirect calorimetry measurements. Digoxin induced a 0.22 +/- 0.07 kJ/min or 3.8 +/- 1.5% (mean +/- SE, P = 0.01) decrease in RMR and a 0.40 +/- 0.13 kJ/min (P = 0.01) decrease in fat oxidation rate, whereas carbohydrate and protein oxidation rates did not change significantly. A dose-response relationship between serum digoxin and RQ was observed. These results suggest that digoxin reduces not only RMR but also fat oxidation rate by mechanisms that remain to be elucidated. Because a linkage and an association between genes coding the Na(+)-K(+)-ATPase and the RQ have been previously observed, the present demonstration of an effect of Na(+)-K(+)-ATPase inhibition on fat oxidation rate strengthens the concept that the activity of this enzyme may play a role in body weight regulation.

Adverse effects of high dose carnitine supplementation of total parenteral nutrition on protein and fat oxidation in the critically ill.

The aim of the present study was to investigate the effects of continuous and acute L-carnitine supplementation of total parenteral nutrition (TPN) on protein and fat oxidation in severe catabolism. A critically ill and severely malnourished male patient received TPN (non protein energy = 41 kcal/kg/day, provided equally as fat and glucose) over 38 days, without L-carnitine for 23 days and with carnitine supplements (15 mg/kg/day) for the following 15 days. Subsequently, he was given carnitine-free enteral nutrition for 60 more days. A four-hour infusion of 100 mg L-carnitine was given on day 11 of each TPN period. Indirect calorimetry was carried out after 11 days of either carnitine-free or supplemented TPN and at the initiation of enteral nutrition. Additional measurements were performed 4 hours and 24 hours after the acute infusions of carnitine. The rate of protein oxidation and the respiratory quotient were found to be higher, and the rate of fat oxidation to be lower, with carnitine-supplemented TPN, than with either carnitine-free TPN or enteral nutrition. Acute infusion of carnitine resulted in an increased rate of protein oxidation and a reduced rate of fat oxidation on both TPN-regimens. These unfavourable effects on protein metabolism may be due to an impairment of fat oxidation by excess amounts of carnitine.

Hindleg muscle energy and substrate balances in cold-exposed rats

Rats chronically cannulated in the carotid artery and the muscular branch of the femoral vein were subjected to a cold (4 °C) environment for up to 2 h. The changes in blood flow (measured with 46Sc microspheres) and arterio-venous differences in the concentrations of glucose, lactate, triacylglycerols and amino acids allowed the estimation of substrate (and energy) balances across the hindleg. Mean glucose uptake was 0.28mmol min21, mean lactate release was 0.33mmol min21 and the free fatty acid basal release of 0.31mmol min21 was practically zero upon exposure to the cold; the initial uptake of triacylglycerols gave place to a massive release following exposure. The measurement of PO·, PCO· and pH also allowed the estimation of oxygen, CO2 and bicarbonate balances and respiratory quotient changes across the hindleg. The contribution of amino acids to the energy balance of the hindleg was assumed to be low. These data were used to determine the sources of energy used to maintain muscle shivering with time. Three distinct phases were observed in hindleg substrate utilization. (1) The onset of shivering, with the use of glucose/glycogen and an increase in lactate efflux. Lipid oxidation was practically zero (respiratory quotient near 1), but the uptake of triacylglycerols from the blood remained unchanged. (2) A substrate-energy shift, with drastically decreased use of glucose/glycogen, and of lactate efflux; utilization of triacylglycerol as practically the sole source of energy (respiratory quotient approximately 0.7); decreasing uptake of triacylglycerol and increased tissue lipid mobilization. (3) The onset of a new heat-homeostasis setting for prolonged cold-exposure, with maintenance of muscle energy and heat production based on triacylglycerol utilization and efflux from the hindleg (muscle plus skin and subcutaneous adipose masses) contributing energy to help sustain heat production by the core organs and surrounding brown adipose tissue.

Neurodevelopmental outcome of neonates treated with nitric oxide for persistent pulmonary hypertension

Persistent pulmonary hypertension of the newborn (PPHN) is a life threatening condition associated with an increased risk of neurodevelopmental impairment. The recommended treatment for this condition is inhaled nitric oxide (iNO) and has been used in our Neonatal Intensive Care Unit since 1998. We prospectively offered neurodevelopmental follow-up to children treated with iNO for PPHN, including extensive neurological evaluation, developmental/cognitive evaluation at 18 months and 3.5-5 years old, and evaluated the rate of severe and moderate handicap and normal neurodevelopmental outcome, compared to a control group and the literature. Population consisted of 29 patients treated only with iNO, born between 01.01.1999 and 31.12.2005 (study group), and 32 healthy term infants born in 1998 in our maternity (control group). During those seven years, 65 infants were admitted in our Unit with PPHN, of whom 40 were treated with iNO alone. 34 children survived (85%) and were offered neurodevelopmental follow-up, 7 children were lost to follow-up due to various reasons. 22 children were examined at the age of 18 months (76%) with a rate of moderate handicap of 22% (2 with expressive language delay, 2 with difficult behavior, and 1 child with moderate hearing loss), and a rate of major handicap of 4.5% (1 child with cerebral palsy due to perinatal stroke, and moderate hearing loss). At preschool age, 17 (50%) were examined, the rate of moderate handicap was 22% (4 borderline intelligence, 1 hearing loss), and the rate of major handicap was 4.5% (one child with cerebral palsy and hearing loss), compared to 26.9% and 0% in the control group. Mean developmental quotient at 18 months was 100.3 ± 8.7 (control group 118.3), and at preschool age mean cognitive indices were within normal limits for the 2 tests performed at 3.5 or 5 years (108 ± 21, 94.4 ± 17). Most of the children with a less favorable neurodevelopmental outcome suffered from birth asphyxia (ruptured uterus, placental abruption, maternal hypotension, diabetic cardiomyopathy), and notably, the 2 children with sensorineural hearing loss both suffered from severe hypoxic-ischemic enkelopathy. Treatment with iNO was not the direct cause of the neurodevelopmental impairments observed in children treated for PPHN.

Family burden related to clinical and functional variables of people with intellectual disability with and without a mental disorder

Few studies have been found that to assess the factors that explain higher levels of familyburden in adults with intellectualdisability (ID) and intellectualdisability and mental disorders (ID-MD). The aims of this study were to assess familyburden in people with ID and ID-MD and to determine which sociodemographic, clinical and functionaldisabilityvariables account for familyburden. The sample is composed of pairs of 203 participants with disability and their caregivers, of which 33.5% are caregivers of people with ID and 66.5% of ID-MD. Assessments were performed using scales of clinical and functionaldisability as the following instruments: Weschler Adult Intelligence Scale-III (WAIS-III), Inventory for Client and Agency Planning (ICAP), Psychiatric Assessment Schedule for Adults with Development Disability (PAS-ADD checklist), Disability Assessment Schedule of the World Health Organization (WHO-DAS-II) and familyburden (Subjective and Objective FamilyBurden Inventory - SOFBI/ECFOS-II). People with ID-MD presented higher levels of functionaldisability than those with ID only. Higher levels of familyburden were related to higher functionaldisability in all the areas (p < 0.006-0.001), lower intelligence quotient (p < 0.001), diagnosis of ID-MD (p < 0.001) and presence of organic, affective, psychotic and behavioral disorders (p < 0.001). Stepwise multiple regression showed that behavioral problems, affective and psychotic disorder, disability in participation in society, disability in personal care and presence of ID-MD explained more than 61% of the variance in familyburden. An integrated approach using effective multidimensional interventions is essential for both people with ID and ID-MD and their caregivers in order to reduce familyburden.

Neurodevelopment outcome of newborns with cerebral subependymal pseudocysts at 18 and 46 months: a prospective study.

OBJECTIVES: Subependymal pseudocysts (SEPC) are cerebral periventricular cysts located on the floor of the lateral ventricle and result from regression of the germinal matrix. They are increasingly diagnosed on neonatal cranial ultrasound. While associated pathologies are reported, information about long-term prognosis is missing, and we aimed to investigate long-term follow-up of these patients. STUDY DESIGN: Newborns diagnosed with SEPC were enrolled for follow-up. Neurodevelopment outcome was assessed at 6, 18 and 46 months of age. RESULTS: 74 newborns were recruited: we found a high rate of antenatal events (63%), premature infants (66% <37 weeks, 31% <32 weeks) and twins (30%). MRI was performed in 31 patients, and cystic periventricular leukomalacia (c-PVL) was primarily falsely diagnosed in 9 of them. Underlying disease was diagnosed in 17 patients, 8 with congenital cytomegalovirus (CMV) infection, 5 with genetic and 4 with metabolic disease. Neurological examination (NE) at birth was normal for patients with SEPCs and no underlying disease, except one. Mean Developmental Quotient and IQ of these patients was 98.2 (±9.6SD; range 77-121), 94.6 (±14.2SD; 71-120) and 99.6 (±12.3SD; 76-120) at 6, 18 and 46 months of age, respectively, with no differences between the subtypes of SEPC. A subset analysis showed no outcome differences between preterm infants with or without SEPC, or between preterm of <32 GA and ≥32 GA. CONCLUSIONS: Neurodevelopment of newborns with SEPC was normal when no underlying disease was present. This study suggests that if NE is normal at birth and congenital CMV infection can be excluded, then no further investigations are needed. Moreover, it is crucial to differentiate SEPC from c-PVL which carries a poor prognosis.

Correlations between negative-induced cerebral dynamics and idiopathic intellectual disability: an EEG study

Intellectual disability has long been associated with deficits in socio-emotional processing. However, studies investigating brain dynamics of maladaptive socio-emotional skills associated with intellectual disability are scarce. Here, we compared differences in brain activity between low intelligence quotient (I.Q.<75, N=13) and normal controls (N=15) while evaluating their subjective emotions. Positive (P) and negative (N) valenced pictures were presented one at a time to participants of both groups, at a rate of ¾. The task required that each participant evaluate their subjective emotion and press a predefined push-button when done, alternatively P and N. Electroencephalographic (EEG) signals were continuously recorded, and the 1000ms time window following each picture was analyzed offline for power in frequency domain. Alpha low (8-10Hz) and upper (10-13Hz) frequency bands were then compared for both groups and for both P and N emotions in 12 distributed scalp electrodes. The qualitative evaluation of emotions was similar between both groups, with constant longer reaction times for the low IQ participants. The EEG signal comparison shows marked power decrease in upper alpha frequency range for N emotions in low intelligence group. Otherwise no significant difference was noticed between low and normal IQ. Main findings of the present study are (1) results do not support the hypothesis that impairment in developmental intelligence roots in maladaptive emotional processing; (2) the strong alpha power suppression during negative-induced emotions suggests the involvement of an extended neural network and more effortful inhibition processes than positive ones. We call for further studies with a larger sample.

A propos des "small area variations": opérations pour fracture de hanche dans le canton de Vaud. [Small area variations: surgery for hip fractures in the canton of Vaud].

OBJECTIVES: Studies of small area variations of health care utilization are more and more frequent. Such variations are often considered to be an indication of variations in the quality of medical care. The variations in the rate of operations for hip fractures are among the lowest studied to date, due to the fact that a consensus exists concerning this surgery. Our objective is to examine these variations within the context of relatively small and heterogeneous districts. METHOD: Based on anonymous computerized data on public hospital stays, this study describes the variations in population rates (crude and standardized) of operations for hip fracture among the health districts of the Canton of Vaud for the period from 1986 to 1991. District populations vary from 22,000 to 164,000. Using the extremal quotient (EQ), the importance of these variations was determined. RESULTS: The study population consists of 2363 cases, of which 78% are women. Mean age is 80.4 for women and 70.6 for men. Standardized rates of operation for hip fracture per 100,000 in the Canton Vaud for the years 1986 to 1991 are, respectively: 56; 67; 86; 91; 89 and 94. The EQ for the years 1986 to 1991 are respectively: 8.2; 4.0; 3.5; 2.7; 1.9 and 1.9. The high EQ, especially for the earlier years, are contrary to the initial premise of absence of variation. The progressive implementation in the Canton Vaud of VESKA medical statistics could play a role, as could the small size of many of the districts, with resultant instability of rates. CONCLUSIONS: Considering the wide variations shown here for an operation hardly regarded as subject to variations, it is important to exercise caution in interpreting published data of small area variations.