Demonstration That Circulating 1α,25-Dihydroxyvitamin D is Loosely Regulated in Normal Children

The effects of vitamin D, 2.5 mg (100,000 U)/d for 4 d, on serum calcium, serum 25-hydroxyvitamin D (25-OHD) and serum 1a,25-dihydroxyvitamin D (1a,25(OH)2D) were compared in 24 normal adults and 12 normal children. The daily dose of vitamin D was 1,500 U/kg body wt in children weighing \u3c45 kg. Vitamin D increased mean serum calcium from 9.5±0.1 to 9.8±0.1 mg/dl (P \u3c 0.05), increased mean serum phosphorus from 4.6±0.1 to 5.0±0.1 mg/dl (P \u3c 0.01), increased mean serum 25-OHD from 25±3 to 34±4 ng/ml (P \u3c 0.001), and increased mean serum 1a,25(OH)2D from 34±3 to 42±4 pg/ml (P \u3c 0.02) in children. In contrast, vitamin D increased mean serum 25-OHD from 18±2 to 39±6 ng/ml (P \u3c 0.001) and did not change mean serum calcium (9.4±0.1 vs. 9.5±0.1 mg/dl), mean serum phosphorus (4.0±0.1 vs. 4.1±0.1 mg/dl), or mean serum 1a,25(OH)2D (31±2 vs. 29±3 pg/ml) in adults. Mean serum 1a,25(OH)2D was significantly higher after vitamin D in children than in adults (P \u3c 0.02). These results provide evidence that circulating 1a,25(OH)2D is not as tightly regulated in children as it is in adults. This difference in regulation could account in part for the higher values for serum 1a,25(OH)2D observed in children

An analysis of the role of serum in parathyroid hormone-induced bone resorption in tissue culture

1. 1. Several chemically-defined media were tested for their capacity to support parathyroid hormone-induced 45Ca release from embryonic bone. None was completely satisfactory.2. 2. A medium consisting of 2 per cent serum in CMRL 1066 would support the parathyroid hormone effect as well as did media containing 50 per cent serum plus 50 per cent CMRL 1066 or 50 per cent Eagle Basal Medium.3. 3. The albumin content of rat serum could be substituted for the whole serum without loss of the observed parathyroid hormone effect. Different albumin preparations varied in their capacity to support the response. Serum globulins, gelatin, histone, heparin or insulin could not replace serum.4. 4. A number of substances enhanced 45Ca release in the absence of parathyroid hormone. Bovine albumin (fraction V) was the most effective preparation tested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33342/1/0000739.pd

Variabilidad de corto plazo y valores extremos de la irradiancia solar en la Pampa Húmeda argentina

Se analizan los cambios abruptos de los niveles de irradiancia global solar en la zona correspondiente a la Pampa Húmeda argentina. Los datos provienen de una red de medición de 9 estaciones distribuidas en la zona. Se contabilizan los incrementos minutales que superen los 300, 400, 500 y 600 W/m2. El análisis se realiza en términos anuales y mensuales, estudiándose la caída de irradiancia porcentual que tales eventos representan. Se encontró que en la mayoría de los casos la caída representa entre el 25% y el 65% de la potencia solar disponible. También se evalúan los valores de irradiancia global que superan la existente a tope de atmósfera. Se sugieren trabajos futuros destinados a evaluar la variabilidad temporal en el desempeño de las plantas fotovoltaicas que operen en dicha zona, un factor que de no ser evaluada convenientemente puede tener consecuencias económicas indeseadas.Sudden changes in solar radiation levels in the Argentine Humid Pampa area are analyzed. The data comes from a measurement network of 9 stations distributed in the area. Minute-wide increases that exceed 300 W/m2, 400 W/m2, 500 W/m2, and 600 W/m2 are considered. The assessment is carried on annual and monthly basis. Falls in percentual irradiance caused by these events are studied. Global irradiance values that exceeds those at the top of the atmosphere are also evaluated. Future works are suggested to prevent the temporal variability of photovoltaic plants that operate in that area, which if not properly evaluated, they might lead to unwanted economic consequences.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Is performance in goal oriented head movements altered in patients with tension type headache?

Background Head repositioning tasks have been used in different experimental and clinical contexts to quantitatively measure motor control performance. Effects of pain on sensorimotor control have often been described in various musculoskeletal conditions and may provide relevant information with regard to potential mechanisms underlying tension-type headaches. The purpose of the current study was to compare the performance of patients with tension-type headache and healthy participants in a cervical aiming task using the Fitts' task paradigm. Methods Patients with tension-type headache and healthy controls were compared in a cervical aiming task. Participants were asked to move their head as quickly, and precisely as possible to a target under various experimental conditions. Dependent variables included movement time, variable error, constant error and absolute error. Results As predicted by Fitts' law, decreasing target size and increasing head rotation amplitudes yielded longer movement times in both groups. Participants with tension-type headache, when compared to healthy participants showed a significant increase in both constant and absolute errors for each of the four conditions. Conclusion Decreased motor performance was observed in participants with tension-type headache, likely due to altered motor control of the neck musculature. Future research is warranted to investigate the clinical aspect related to decrease in motor performance. Keywords: Tension type headaches, Motor control, Cervical spine, Kinesthetic sens

Evidence for Extrarenal Production of 1a,25-Dihydroxyvitamin D in Man

Recent studies provide evidence for extrarenal production of 1a,25-dihydroxyvitamin D [1a,25(OH)2D]. To investigate this possibility, serum vitamin D, 25-hydroxyvitamin D (25-OHD), 24,25-dihydroxyvitamin D [24,25(OH)2D], and 1a,25(OH)2D were measured in eight adult anephric subjects. All were undergoing hemodialysis and three of them were receiving vitamin D, 50,000 or 100,000 U/d. Serum vitamin D was elevated in two of the patients given vitamin D and was abnormally low in the others. Mean serum 25-OHD was increased in patients given vitamin D (94.0±7.6 ng/ml) and was normal in the others (16.4±0.9 ng/ml, P \u3c 0.001). Mean serum 24,25(OH)2D was normal in patients given vitamin D (1.38±0.27 ng/ml) and was low in the others (0.25±0.08 ng/ml, P \u3c 0.001). Serum 24,25(OH)2D correlated significantly with serum 25-OHD (r = 0.848, P \u3c 0.01). Mean serum 1a,25(OH)2D determined by receptor assay was 5.8±1.9 pg/ml in patients who were not given vitamin D and was 14.1±0.6 in those who were given vitamin D (P \u3c 0.001). Serum 1a,25(OH)2D correlated significantly with serum 25-OHD (r = 0.911, P \u3c 0.01). Mean serum 1a,25(OH)2D, measured by bioassay, was 8.3±1.9 pg/ml in patients who were not given vitamin D and was 15.9±2.4 pg/ml in those who were given vitamin D (P \u3c 0.05). There was a significant correlation between the values for serum 1a,25(OH)2D obtained with the two methods (r = 0.728, P \u3c 0.01). The results (a) provide evidence in man for extrarenal production of both 24,25(OH)2D and, by two independent assays, of 1a,25(OH)2D, and (b) indicate that serum values of the two dihydroxy metabolites of vitamin D in anephric subjects vary with the serum concentration of the precursor 25-OHD

Mucosal competitive exclusion to reduce salmonella in swine

Food contamination due to Salmonella is the cause oflarge numbers of human food-borne illnesses worldwide. Reduction in fecal shedding and prevention of new Salmonella infections in livestock during the late finishing/marketing phase of production are critical control points associated with human food safety. The objectives of this research were to compare the effects of various treatments on the shedding of Salmonella during the late finishing phase of production in littermate swine reared nnder different management conditions. The treatments compared were: I) multi-site segregated early weaning (SEW) versus ontinuous flow (CF) rearing of swine, 2) growth promotant antibiotics (medicated) versus no feed antibiotics (unmedicated), 3) 24 hour fasting versus full- feeding

Influence of cognitive reserve in schizophrenia: A systematic review

Objective: To perform a systematic review of the influence of sociobehavioural indicators of cognitive reserve (CR) in the risk of schizophrenia, the clinical manifestations of the disease, and cognitive intervention programs (CRT) carried out with these patients. Method: A cross search was made by two independent reviewers in Pubmed and PsycINFO databases using keywords “schizophrenia” and “cognitive reserve.” Twenty-one studies which analyzed different CR proxies were selected and the level of evidence was classified according to the Oxford Centre for Evidence-Based Medicine. Result: People with higher CR may have a lower risk of developing schizophrenia and a later onset of disease. In addition, they present better neuropsychological and functional performance in the illness course. However, the suspected influence of CR on the effectiveness of CRT in patients with schizophrenia is currently unresolved. Conclusion: Our findings suggest that higher CR delays the clinical diagnosis threshold and severity of the symptoms in patients with schizophrenia. However, effect of singular sociobehavioral measures on clinical expression and benefits of intervention program need further investigation