Driving a Superconductor to Insulator Transition with Random Gauge Fields.

Typically the disorder that alters the interference of particle waves to produce Anderson localization is potential scattering from randomly placed impurities. Here we show that disorder in the form of random gauge fields that act directly on particle phases can also drive localization. We present evidence of a superfluid bose glass to insulator transition at a critical level of this gauge field disorder in a nano-patterned array of amorphous Bi islands. This transition shows signs of metallic transport near the critical point characterized by a resistance , indicative of a quantum phase transition. The critical disorder depends on interisland coupling in agreement with recent Quantum Monte Carlo simulations. We discuss how this disorder tuned SIT differs from the common frustration tuned SIT that also occurs in magnetic fields. Its discovery enables new high fidelity comparisons between theoretical and experimental studies of disorder effects on quantum critical systems.

Observation of giant positive magnetoresistance in a Cooper pair insulator.

Ultrathin amorphous Bi films, patterned with a nanohoneycomb array of holes, can exhibit an insulating phase with transport dominated by the incoherent motion of Cooper pairs (CP) of electrons between localized states. Here, we show that the magnetoresistance (MR) of this Cooper pair insulator (CPI) phase is positive and grows exponentially with decreasing temperature T, for T well below the pair formation temperature. It peaks at a field estimated to be sufficient to break the pairs and then decreases monotonically into a regime in which the film resistance assumes the T dependence appropriate for weakly localized single electron transport. We discuss how these results support proposals that the large MR peaks in other unpatterned, ultrathin film systems disclose a CPI phase and provide new insight into the CP localization.

Determinants of hospital costs in community-acquired pneumonia.

Community-acquired pneumonia (CAP) has a high incidence and involves an important consumption of healthcare resources. The present authors analysed the influence of comorbidity, initial severity and complications upon the direct costs associated with hospitalised CAP patients. Direct hospitalisation costs (room cost, treatment, laboratory and diagnostic tests) were assessed in a prospective, observational study of 271 patients admitted to a hospital ward due to CAP. The mean+/-SD patient age was 70+/-15 yrs. The mortality rate was 11.1%. Complications were found in 72.3% and comorbidities in 74.9%. The median (interquartile range) total cost was 1,683 euros (1,291-2,471 euros) and the component costs were: room cost 1,286 euros (857-1,714 euros); laboratory tests 212 euros (171-272 euros); treatment 187 euros (114-304 euros); and diagnostic procedures 58 euros (29-122 euros). Complications and higher Pneumonia Severity Index increased the costs, but age and comorbidity did not. A logistic regression analysis to predict high cost (>1,683 euros) showed that infectious (odds ratio 6.8, 95% confidence interval 1.3-36), digestive (5.9 (1.5-22.8)), pulmonary (2.6 (1.4-4.7)) and other complications (3.9 (1.8-8.4)) were independent risk factors, as were previous hospitalisation (2.3 (1.2-4.3)) and hypoalbuminaemia (2 (1.1-3.6)). Complications, hypoalbuminaemia and previous hospitalisation were the main determinants of high direct costs of hospitalisation due to community-acquired pneumonia. Neither age nor comorbidities were independently associated with cost.

Magnetic levitation-based Martian and Lunar gravity simulator.

Missions to Mars will subject living specimens to a range of low gravity environments. Deleterious biological effects of prolonged exposure to Martian gravity (0.38 g), Lunar gravity (0.17 g), and microgravity are expected, but the mechanisms involved and potential for remedies are unknown. We are proposing the development of a facility that provides a simulated Martian and Lunar gravity environment for experiments on biological systems in a well controlled laboratory setting. The magnetic adjustable gravity simulator will employ intense, inhomogeneous magnetic fields to exert magnetic body forces on a specimen that oppose the body force of gravity. By adjusting the magnetic field, it is possible to continuously adjust the total body force acting on a specimen. The simulator system considered consists of a superconducting solenoid with a room temperature bore sufficiently large to accommodate small whole organisms, cell cultures, and gravity sensitive bio-molecular solutions. It will have good optical access so that the organisms can be viewed in situ. This facility will be valuable for experimental observations and public demonstrations of systems in simulated reduced gravity.

Initial risk class and length of hospital stay in community-acquired pneumonia.

The total medical costs of community-acquired pneumonia are directly related to the costs of hospital admission and length of stay. The aim of the present study was to evaluate the reasons for prolonged duration of stay in patients stratified in five risk classes for death, and to identify factors associated with prolonged stay. The study population consisted of 295 patients. According to lower (classes I, II, III) or to higher (classes IV, V) risk, the target duration of hospitalization was set at 5 and 7 days, respectively. The causes of prolonged hospitalization were classified as pneumonia-related, complications, unstable comorbid diseases and nonclinical factors. The overall percentage of patients with appropriate duration of hospitalization was 32%. Causes of prolonged hospitalization were related mainly to pneumonia (32%) from all risk classes. Morbid complications and instability of the underlying illness were greater in class V patients. Nonclinical factors were present in 29.5% of cases. Hypoxaemia, anaemia, hypoalbuminaemia, and complications appearing before 72 h were associated with prolonged hospitalization. The cause of prolonged hospitalization of patients with community-acquired pneumonia is multifactorial, depending mainly on pneumonia and comorbid conditions but there is a large number of unnecessary hospitalization days that could be reduced by improving the efficiency of hospital care.

Cleavage planes in frog eggs are altered by strong magnetic fields.

Early cleavages of Xenopus embryos were oriented in strong, static magnetic fields. Third-cleavage planes, normally horizontal, were seen to orient to a vertical plane parallel with a vertical magnetic field. Second cleavages, normally vertical, could also be oriented by applying a horizontal magnetic field. We argue that these changes in cleavage-furrow geometries result from changes in the orientation of the mitotic apparatus. We hypothesize that the magnetic field acts directly on the microtubules of the mitotic apparatus. Considerations of the length of the astral microtubules, their diamagnetic anisotropy, and flexural rigidity predict the required field strength for an effect that agrees with the data. This observation provides a clear example of a static magnetic-field effect on a fundamental cellular process, cell division.

Stable magnetic field gradient levitation of Xenopus laevis: toward low-gravity simulation.

We have levitated, for the first time, living biological specimens, embryos of the frog Xenopus laevis, using a large inhomogeneous magnetic field. The magnetic field/field gradient product required for levitation was 1430 kG2/cm, consistent with the embryo's susceptibility being dominated by the diamagnetism of water and protein. We show that unlike any other earth-based technique, magnetic field gradient levitation of embryos reduces the body forces and gravity-induced stresses on them. We discuss the use of large inhomogeneous magnetic fields as a probe for gravitationally sensitive phenomena in biological specimens.

Effects of selective phosphodiesterase inhibitors on platelet-activating factor- and antigen-induced airway hyperreactivity, eosinophil accumulation, and microvascular leakage in guinea pigs.

There is currently interest in the potential use of selective inhibitors of cyclic nucleotide phosphodiesterases (PDE) in the treatment of asthma. In this study we examined the effects of three selective PDE inhibitors, milrinone (PDE III), rolipram (PDE IV) and zaprinast (PDE V), on the broncoconstriction produced by antigen and histamine, the airway hyperreactivity and microvascular leakage after aerosol exposure to platelet-activating factor (PAF) and antigen, and the antigen-induced eosinophil infiltration in guinea-pig lung. Inhaled rolipram (0.01-10 mg ml-1) inhibited dose dependently the bronchospasm produced by aerosol antigen (5 mg ml-1) an anaesthetised, ventilated guinea-pigs. Rolipram (10 mg ml-1) produced maximal inhibition of antigen-induced bronchoconstriction but only partial inhibition of the response to aerosol histamine (1 mg ml-1). Milrinone and zaprinast (each 10 mg ml-1) showed weak, or no, inhibitory effects against bronchoconstriction produced by aerosol antigen or histamine. Pretreatment with rolipram (10 mg kg-1, i.p.) prevented airway hyperreactivity to histamine which develops 24 h after exposure of conscious guinea-pigs to aerosol PAF (500 micrograms ml-1) or antigen (5 mg ml-1). The pulmonary eosinophil infiltration obtained with 24 h of antigen-exposure was inhibited by rolipram. In contrast, milrinone and zaprinast (each 10 mg kg-1, i.p.) failed to reduce either the airway hyperreactivity of the eosinophil accumulation in these animals. Rolipram (1-10 mg ml-1) reduced the extravasation of Evans blue after aerosol PAF (500 micrograms ml-1) at all airway levels while a lower dose (0.1 mg ml-1) was only effective at intrapulmonary airways. Rolipram (0.01-1 mg ml-1) markedly reduced airway extravasation produced by inhaled antigen (5 mg ml-1). Zaprinast (1-10 mg ml-1) was also effective against airway microvascular leakage produced by aerosol PAF or antigen while milrinone (10 mg ml-1) had no antiexudative effect. These data support previous suggestions that pharmacological inhibition of PDE IV results in anti-spasmogenic and anti-inflammatory effects in the airways and may be useful in the treatment of asthma.

Rolipram inhibits airway microvascular leakage induced by platelet-activating factor, histamine and bradykinin in guinea-pigs.

Rolipram (0.1-1000 micrograms kg-1, i.v.) reduced the increase in microvascular permeability induced by platelet-activating factor (PAF; 50 ng kg-1, i.v.) at different sites of the guinea-pig airways. Rolipram (1-100 micrograms kg-1, i.v.) inhibited histamine (30 micrograms kg-1, i.v.)- and bradykinin (0.3 micrograms kg-1, i.v.)-induced airway microvascular leakage. These effects of rolipram were obtained at doses which inhibit histamine (7-20 micrograms kg-1 min-1)-induced bronchoconstriction (IC50 = 3 +/- 1 micrograms kg-1, i.v.) without depressing arterial blood pressure in the guinea-pig. Aminophylline (50 mg kg-1) did not change the effect of PAF. The anti-exudative effect of rolipram is of potential therapeutic value in asthma.

Rolipram inhibits PAF-induced airway microvascular leakage in guinea-pig: a comparison with milrinone and theophylline.

The effects of 3 phosphodiesterase (PDE) inhibitors, rolipram (PDE IV), milrinone (PDE III) and theophylline (non-selective) on PAF (50 ng kg-1; iv)-induced airway vascular leakage have been evaluated in guinea-pigs. Rolipram (3-300 micrograms kg-1; iv) reduced the increase in permeability induced by PAF at all airway levels whereas milrinone (10-1000 micrograms kg-1; iv) and theophylline (30 mg kg-1; iv) were without effects. The anti-leakage activity of rolipram may be of therapeutic value in asthma.

[Newborn of diabetic mother]. / Recién nacido hijo de madre diabética.

OBJECTIVE: Shows the general findings in a cohort of newborn babies born to diabetic mothers. DESIGN: Prospective and observational study, during a year (1988). PLACE: Hospital de Ginecoobstetricia del Centro Médico "La Raza", a terciary Center. RESULTS: There were 92 newborn babies born to diabetic mothers; 62 were delivery with cesarean section and 30 were vaginally; 51 were males and 41 females; with 49% prematurelly born, 38% with macrosomia; there were eight stillbirths and four neonatal deaths, with a perinatal mortality of 13%. From the live born babies in 50% had any problem with icterus in 40%, respiratory insufficiency in 22.5%, hypoglycemia in 16.2% and polycytemia in 13%; 44.5% had an uncomplicate course. There were five patients with congenital anomalies. CONCLUSIONS: The newborn baby born to diabetic mother needed a special control from early stages of pregnancy, preferable for a interdisciplinary medical team, with the goal to obtained in our perinatal mortality rate will be similar to published in the international literature, lesser of 2%.

Lack of correlation between lithium pharmacokinetic parameters obtained from plasma and saliva.

One tablet containing 755 mg of lithium tryptophanate (10.8 mEq of lithium) was administered to eight healthy volunteers. The main pharmacokinetic parameters for the group of subjects were estimated. Pharmacokinetic parameters (mean +/- SD) from plasma and saliva were respectively: half life (t1/2) 17 +/- 6 vs. 21.8 +/- 14 h; mean residence time 23.7 +/- 7.4 vs. 24.4 +/- 15.3 h; total clearance 30.6 +/- 9.3 vs. 28.6 +/- 6.2 ml/h/kg; and apparent volume of distribution 0.71 +/- 0.20 vs. 0.84 +/- 0.37 L/kg. Although the mean pharmacokinetic parameters in plasma and saliva were similar, there was no significant correlation between the calculated parameters in the individual subject (p greater than 0.05). The usefulness of monitoring salivary levels of lithium is questionable.

A two-generation reproduction-fertility study of cyanamide in the rat.

A two-generation reproduction-fertility study of cyanamide in the rat has been carried out. After oral administration of 2, 7 and 25 mg/kg/day of the drug, relevant changes have been noted at the highest dose level. Decrease in dam weight gain, in number of corpora lutea, in number of implantations and in number of neonates have been observed in rats of the Fo generation after treatment with 25 mg/kg/day. This group showed a reduced fertility rate and decreases in the weight of several reproductive organs male rats. In contrast to the findings noted in the Fo generation, changes related to cyanamide treatment have not been observed in the F1 generation. Histopathology of these organs has disclosed a low incidence of bilateral testicular atrophy. Decreased fertility rate due to non-specific toxicity associated with a diminished food intake cannot be discarded.

Effects of cyanamide on body weight and brain monoamines and metabolites in rats.

Cyanamide, a disulfiram-like drug used in the treatment of alcoholism, decreased in a dose-dependent manner (2-25 mg/kg) the body weight gain curve in rats, which resulted in a marked decrease of body weight (10-35%). Long-term administration of cyanamide also decreased food intake (6-34%) in a dose-dependent manner (2-25 mg/kg). Both effects of cyanamide were reversible. After the acute and long-term administration (1-12 months) of cyanamide (8-35 mg/kg) the brain concentration of 3-methoxy-4-hydroxyphenylethyleneglycol sulphate (MOPEG-SO4) was also significantly increased (26-46%). Cyanamide, however, had no effects on the brain concentration of noradrenaline, dopamine, 5-hydroxytryptamine, tryptophan and 5-hydroxyindolacetic acid. It is suggested that the loss of weight, the decrease in food intake and the increase in brain MOPEG-SO4 induced by cyanamide reflect possible anorectic properties of the drug.

Bioavailability of cyanamide in fasted and unfasted rats.

The pharmacokinetics of cyanamide after 35 mg kg-1 intravenous and oral administration to fasted and unfasted rats have been investigated. The plasma level are fitted well by a two-compartment open model. The half-life (t 1/2 beta) of cyanamide in the rat was 1 hour and the plasma clearance (C1p) was 0.02 (1 kg-1) min-1. Food does not appear to modify the absolute bioavailability of cyanamide (F = 93.3 per cent fasted, F = 85.5 per cent unfasted), although it does retard drug absorption.

Determination of cyanamide in plasma by high-performance liquid chromatography.

A sensitive, selective and rapid high-performance liquid chromatographic procedure was developed for the determination of cyanamide in plasma. The procedure involved extraction with ethyl acetate, derivatization with 5-(dimethylamino)naphthalene-1-sulphonyl chloride and posterior analysis by high-performance liquid chromatography on a mu Bondapak C18 column with fluorimetric detection. Linearity ranged from 5 to 500 ng/ml and the lower limit of sensitivity of the assay was 4 ng/ml of cyanamide in plasma. The precision of the method was 3.0-8.9%, expressed as relative standard deviation over the linear range. This method has been used to elucidate the time course of the cyanamide concentration in the plasma of humans, following oral administration of cyanamide at therapeutic doses.

Lack of hepatotoxicity after long-term administration of cyanamide in rats: a histological and biochemical study.

An experimental long-term hepatotoxicity study of cyanamide in Sprague-Dawley and Wistar rats has been carried out. After six months oral administration of cyanamide (2.7 and 25 mg/kg/day) no significant histological changes have been observed in the liver. Similarly, a one year intraperitoneal administration of 8 and 16 mg/kg/day has not induced any hepatic change. Specifically, no inclusion bodies in any cyanamide treated rat have been detected. Moreover, hepatic biochemical parameters have shown no significant impairment of hepatic function at doses used in human therapy (0.5-1 mg/kg).

The pharmacokinetic profile of carbidopa in dogs.

A pharmacokinetic study of carbidopa in beagle dogs has been carried out after intravenous (4 mg kg-1) and oral (75 mg) administration. An open model of three compartments was the best approach for the pharmacokinetic profile of carbidopa administered intravenously. The estimated biological t1/2 was 5 h and the plasma clearance 0.0053 (litre kg-1) min-1. The oral absorption of carbidopa was almost complete and the absolute bioavailability (F) was 88%.