Multifractal analysis to study break points in temperature data sets

Since the last century, the air surface temperature has increased at a global scale, showing trends and inhomogeneities that vary from place to place. Many statistical methods can be used to analyze whether or not an inhomogeneity or break point exists in a meteorological data series, and even to detect the time of the break. Sometimes, there is no agreement in the year at which the inhomogeneity occurs detected by different tests. The scale invariance of a process can be studied through its multifractal properties that can be related to the existence of break points in it. In this work, the multifractal properties of monthly temperature data series are used to test what is the right break point year in those situations at which different dates are found by two different tests: the Pettitt and the Standard Normal Homogeneity tests. The comparison of the fractal dimension function D_q and the multifractal spectrum obtained by the box counting method for both the original data sets and for those obtained by splitting the original into two considering the break point years was made. When different multifractal functions and parameters were obtained, a break point was confirmed. Whereas, if equal values appeared, the break point year was discarded. These results let to select the most suitable test to be applied to detect inhomogeneities in a certain data set that will be very useful for climate change studies.

Multifractal analysis of diurnal temperature range over Southern Spain using validated datasets

Multifractal properties of diurnal temperature range (DTR) have been analyzed in this work, using validated data of maximum and minimum temperature from 197 weather stations in Southern Spain (Andalusia region). DTR is a crucial factor to characterize the regional climate, providing more information than the average daily temperature. Apart from climate change studies, one of the most important applications of DTR in Agrometeorology is as an input variable in the solar radiation or reference evapotranspiration estimation models based on the temperature. With the aim of obtaining a detailed information for different time scales, different multifractal approaches have been applied. Different quality control methods such as range/limits or persistence tests were previously applied in order to detect incorrect and anomalous values, being discarded in the subsequent analysis. The DTR scaling of moments has been analyzed and the moment scaling exponent function K(q) has been obtained, finding some differences between weather stations. In addition, multifractal dimension (D1) and multifractal degree (MD) were also estimated, revealing differences at coastal and inland locations that show heterogeneity across the region, including its multifractal nature and its invariance for a range of scales. The nonlinear characterization carried out in this work improves the understanding of DTR as an indicator of climate changes, and it can have a very positive impact on the calibration of regional models for estimating solar radiation or reference evapotranspiration based on the temperature. This multifractal characterization can be used to group stations with similar nonlinear dynamics, regardless of their geographical features, in such a way that more accurate coefficients than conventional ones are used.

Resolving pathways of interaction of mipafox and a sarin analog with human acetylcholinesterase by kinetics, mass spectrometry and molecular modeling approaches

The hydroxyl oxygen of the catalytic triad serine in the active center of serine hydrolase acetylcholinesterase (AChE) attacks organophosphorus compounds (OPs) at the phosphorus atom to displace the primary leaving group and to form a covalent bond. Inhibited AChE can be reactivated by cleavage of the Ser-phosphorus bond either spontaneously or through a reaction with nucleophilic agents, such as oximes. At the same time, the inhibited AChE adduct can lose part of the molecule by progressive dealkylation over time in a process called aging. Reactivation of the aged enzyme has not yet been demonstrated. Here, our goal was to study oxime reactivation and aging reactions of human AChE inhibited by mipafox or a sarin analog (Flu-MPs, fluorescent methylphosphonate). Progressive reactivation was observed after Flu-MPs inhibition using oxime 2-PAM. However, no reactivation was observed after mipafox inhibition with 2-PAM or the more potent oximes used. A peptide fingerprinted mass spectrometry (MS) method, which clearly distinguished the peptide with the active serine (active center peptide, ACP) of the human AChE adducted with OPs, was developed by MALDI-TOF and MALDI-TOF/TOF. The ACP was detected with a diethyl-phosphorylated adduct after paraoxon inhibition, and with an isopropylmethyl-phosphonylated and a methyl-phosphonylated adduct after Flu-MPs inhibition and subsequent aging. Nevertheless, nonaged nonreactivated complexes were seen after mipafox inhibition and incubation with oximes, where MS data showed an ACP with an NN diisopropyl phosphoryl adduct. The kinetic experiments showed no reactivation of activity. The computational molecular model analysis of the mipafox-inhibited hAChE plots of energy versus distance between the atoms separated by dealkylation showed a high energy demand, thus little aging probability. However, with Flu-MPs and DFP, where aging was observed in our MS data and in previously published crystal structures, the energy demand calculated in modeling was lower and, consequently, aging appeared as a more likely reaction. We document here direct evidence for a phosphorylated hAChE refractory to oxime reactivation, although we observed no aging.

High NaCl concentrations induce the nod genes of Rhizobium tropici CIAT899 in the absence of flavonoid inducers

The nodulation (nod) genes of Rhizobium tropici CIAT899 can be induced by very low concentrations (micromolar to nanomolar range) of several flavonoid molecules secreted by the roots of leguminous plants under a number of different conditions. Some of these conditions have been investigated and appear to have a great influence on the concentration and the number of different Nod factors, which can induce root nodule primordia and pseudonodules in several leguminous plant roots. In one such condition, we added up to 300 mM NaCl to the induction medium of R. tropici CIAT899 containing the nod gene inducer apigenin. At the higher concentrations of NaCl, larger amounts and more different Nod factors were produced than in the absence of extra NaCl. To our surprise, under control conditions (300 mM NaCl without apigenin), some Nod-factor-like spots were also observed on the thin-layer plates used to detect incorporation of radiolabeled glucosamine into newly synthesized Nod factors. This phenomenon was further investigated with thin-layer plates, fusions of nod genes to the lacZ gene, high-performance liquid chromatography, mass spectrometry, and the formation of pseudonodules on bean roots. Here, we report that, in the absence of flavonoid inducers, high concentrations of NaCl induced nod genes and the production of Nod factors.

Multifractal analysis of validated wind speed time series

Multifractal properties of 30 min wind data series recorded at six locations in Cadiz (Southern Spain) have been studied in this work with the aim of obtaining detailed information for a range of time scales. Wind speed records have been validated, applying various quality control tests as a pre-requisite before their use, improving the reliability of the results due to the identification of incorrect values which have been discarded in the analysis. The scaling of the wind speed moments has been analysed and empirical moments scaling exponent functions K(q) have been obtained. Although the same critical moment (qcrit) has been obtained for all the places, some differences appear in other multifractal parameters like γmax and the value of K(0). These differences have been related to the presence of extreme events and zero data values in the data series analysed, respectively.

Patient age and biological aggressiveness of endometrial carcinoma

BACKGROUND

Advanced age is associated with a significantly worse prognosis of endometrial carcinoma patients. The aim of this study was to test whether age is a poor-risk factor in endometrial carcinoma because tumors arising in older patients are biologically different from those diagnosed in patients of an earlier age.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded samples from 136 previously untreated patients with endometrial carcinoma were studied by means of immunohistochemistry. The expression of molecular markers associated with hormone responsiveness (estrogen and progesterone receptors), proliferation (Ki67, C-ERB-B2, p53), invasiveness (E-cadherin) and apoptosis (BCL2 and p53) was analyzed. The obtained expression levels, together with all available clinical and pathological features were tested for correlations with the patients age and survival.

RESULTS

Advanced patient age showed a direct correlation with tumor stage (r=0.29, p=0.0008) and mutant p53 expression (r=0.25, p=0.004), and an inverse correlation with E-cadherin expression (r=-0.28, p=0.001). Patient age above the 25th percentile (57 years) of the age distribution was significantly associated with a worse prognosis (p=0.018).

CONCLUSION

It appears that with advancing age, endometrial carcinoma exhibits a more aggressive tumor phenotype, characterized by mutant p53 expression and down-regulation of E-cadherin expression, and that this, in its turn, results in tumors being diagnosed at a more advanced stage in older patients.

Data validation procedures in agricultural meteorology – a prerequisite for their use

Abstract. Quality meteorological data sources are critical to scientists, engineers, climate assessments and to make climate related decisions. Accurate quantification of reference evapotranspiration (ET0) in irrigated agriculture is crucial for optimizing crop production, planning and managing irrigation, and for using water resources efficiently. Validation of data insures that the information needed is been properly generated, identifies incorrect values and detects problems that require immediate maintenance attention. The Agroclimatic Information Network of Andalusia at present provides daily estimations of ET0 using meteorological information collected by nearly of one hundred automatic weather stations. It is currently used for technicians and farmers to generate irrigation schedules. Data validation is essential in this context and then, diverse quality control procedures have been applied for each station. Daily average of several meteorological variables were analysed (air temperature, relative humidity and rainfall). The main objective of this study was to develop a quality control system for daily meteorological data which could be applied on any platform and using open source code. Each procedure will either accept the datum as being true or reject the datum and label it as an outlier. The number of outliers for each variable is related to a dynamic range used on each test. Finally, geographical distribution of the outliers was analysed. The study underscores the fact that it is necessary to use different ranges for each station, variable and test to keep the rate of error uniform across the region.

[Study on the venoms of the principal venomous snakes from French Guiana and the neutralization]

We studied some biochemical, toxic and immunological characteristics of the venoms of Bothrops atrox, Bothrops brazili and Lachesis muta, Viperidae responsible for most of the bites of venomous snakes in French Guiana. Chromatographic (HPLC) and electrophoretical profiles (SDS-PAGE), lethal, hemorrhagic, defibrinogenating, coagulant, thrombin like, proteolytic, fibrino(geno)lytic and phospholipase activities were studied. In addition, the neutralization of some toxic activities conferred by four antivenins was compared. The chromatographic and electrophoretic profiles were different for the three venoms, showing differences between Bothrops and L. muta venoms. In general, bothropic venoms showed the highest toxic and enzymatic activities, while the venom of L. muta showed the lowest lethal, hemorrhagic and coagulant activities. The enzymes of bothropic venoms responsible for gelatinolytic activity were around 50-90 kDa. All the venoms were able to hydrolyze a and beta chains of the fibrinogen, showing different patterns of degradation. Although all the antivenoms tested were effective to various degrees in neutralizing the venom of B. brazili and B. atrox, neutralization of L. muta venom was significantly better achieved using the antivenom including this venom in its immunogenic mixture. For the neutralization of L. muta venom, homologous or polyvalent antivenoms that include the "bushmaster" venom in their immunogenic mixture should be preferred.

Cytological image analysis with a genetic fuzzy finite state machine

The objective of this research is to design a pattern recognition system based on a Fuzzy Finite State Machine (FFSM). We try to find an optimal FFSM with Genetic Algorithms (GA). In order to validate this system, the classifier has been applied to a real problem: distinction between normal and abnormal cells in cytological breast fine needle aspirate images and cytological peritoneal fluid images. The characteristic used in the discrimination between normal and abnormal cells is a texture measurement of the chromatin distribution in cellular nuclei. Furthermore, the effectiveness of this method as a pattern classifier is compared with other existing supervised and unsupervised methods and evaluated with Receiver Operating Curves (ROC) methodology.

[Serum levels of soluble CD30 molecule in hepatitis B virus infection]

BACKGROUND

The release of CD30 molecule in the soluble form (sCD30) is considered a feature of Th2 activation and proliferation of the cellular phenotype Th2.

AIM

To analyze the immunoregulatory role of sCD30 in the evolution of hepatitis B virus (HBV) infection.

PATIENTS AND METHODS

Three study groups were formed: 15 patients with acute infection by HBV who remitted toward the resolution of the infection; 15 patients who evolved to the carrier state and 15 subjects without clinical history of infection by this or other viruses. The determination of serological markers for the HBV was done by the Microparticles Enzymatic Immunoanalysis techniques (MEIA). The method of double antibody by ELISA was used For sCD30 determination.

RESULTS

A significant sCD30 increase (p < 0.05) was observed in patients with acute infection, during the acute phase (135.7 +/- 36.7). These values decreased to 16.2 +/- 2.5 during the convalescent phase. Patients that evolved to the carrier state, did not experience a rise in sCD30 values (40.2 +/- 6.7, 38 +/- 9.2 and 36.1 +/- 8.3 during the acute phase, at 120 and 240 days respectively). The value in the control group was 34.8 +/- 6.7.

CONCLUSIONS

The group that evolved towards remission experienced a higher activation of the Th2 cellular phenotype, promoting humoral immune response. An inactivity of sCD30 values was observed in the group that evolved to the carrier state.

[Effect of oral and intramuscular vitamin K on the factors II, VII, IX, X, and PIVKA II in the infant newborn under 60 days of age]

BACKGROUND

Neonates on exclusive breast feeding that do not receive vitamin K at birth are at higher risk hemorrhagic disease of the newborn.

AIM

To compare the effect of oral or intramuscular administration of vitamin K1 (VK1), on clotting factors II, VII, IX, X and PIVKA II, in children until the 60 days of age with exclusive breast feeding or mixed feeding.

PATIENTS AND METHODS

Forty healthy full term infants, distributed in two groups, A: 20 with mixed feeding (formula-feeding and breast-feeding) and B: 20 with exclusive breast feeding, were studied. Nine infants of each group received 1 mg of VK1 intramuscularly and eleven 2 mg VK orally 5 ml of cord blood was collected initially from each infant. Venous blood samples were taken on 15, 30 and 60 days of age.

RESULTS

All factors increased in a progressive form reaching levels over 50% at 60 days of age, in both groups. PIVKA II decreased significantly during the study period (p < 0.01). Factor II increased more in children with mixed feeding that received intramuscular vitamin K, than in the rest of study groups. No other differences between groups were observed. No infant had an abnormal bleeding during the study period.

CONCLUSIONS

Oral administration of vitamin K is as effective as the intramuscular route in the prevention of the hemorrhagic disease of the newborn.

Effect of chronic manganese treatment on adenosine tissue levels and adenosine A2a receptor binding in diverse regions of mouse brain

In the present study the effects of chronic manganese (Mn) treatment on adenosine A2a receptor binding in mouse brain have been assessed. Male albino mice were divided in two groups: In the Mn-treated group, the animals were injected intraperitoneally (i.p.) with MnCl2 (5 mg/kg/day) five days per week during 9 weeks; in the control group, they were injected likewise with a saline solution. A significant decrease of the Kd without alteration of Bmax in the cerebellum and, an increase of the Kd and Bmax in hippocampus of mice treated with Mn were found. Also, an increase of Kd in frontal cortex was observed. The binding parameters in caudate nucleus, olfactory bulb and hypothalamus were not altered by Mn. A significant decrease in the adenosine concentration in caudate nucleus, olfactory bulb and hypothalamus, without significant changes in hippocampus, frontal cortex and cerebellum was also detected. These findings suggest that chronic administration of Mn could affect adenosine receptor function and turnover, depending on the brain region analyzed.

Cyclospora cayetanensis infections among diarrheal patients from Venezuela

The prevalence and importance of Cyclospora cayetanensis as an enteropathogen among 71 patients (22-45 years old) with acquired immunodeficiency syndrome (AIDS) and 132 children with diarrhea (0-12 years old) from Venezuela was assessed retrospectively. Two to three stool samples from each patient attending our parasitology laboratory for parasitologic and medical assistance were examined. For identification of the coccidium, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether stool concentrates was used, and for other intestinal parasites, iron-hematoxylin-stained smears and formalin-ether concentrates were examined. Cyclospora oocysts were found in seven (9.8%) of 71 AIDS patients and seven (5.3%) of 132 children with diarrhea. Other pathogenic parasites were present in most of the patients (9 of 14, 64.3%) shedding oocysts. Cyclosporiasis predominated in children 2-5 years of age with respect to those < or = one year of age (P < 0.05). The findings suggest that C. cayetanensis is common in diarrheal patients from Venezuela. However, the role of the parasite as the causal agent of diarrhea in these patients is uncertain.

[Seroepidemiology of Herpes simplex virus type 2 in the Amerindian Yukpa population of Zulia state, Venezuela]

BACKGROUND

Yukpa aborigines start early in life their sexual activity and promiscuity with native and foreign individuals is common among women. This behavior allows the installation and propagation of Herpes simplex virus type 2 (HSV-2).

AIM

To determine the presence of antibodies to HSV-2 in a Yukpa Amerindian community at Zulia State, Venezuela.

SUBJECTS AND METHODS

We studied 96 natives, between 13 and 49 years old (62.3% of the whole population, 100% of individuals in fertile age). Control population consisted of 76 individuals, with similar sex and age range distribution, of the urban population from Maracaibo, Zulia State, Venezuela. HSV-2 serologic status was determined by an indirect fluorescent antibody test.

RESULTS

Antibodies to HSV-2 were detected in 53.1% of Yukpa population and 21.1% of urban population. Aboriginal women aged 21 to 40 years old had a prevalence of antibodies against HSV-2 of 66.7%. Among pregnant native women, the prevalence of antibodies against HSV-2 was 54.6%.

CONCLUSIONS

There is a high prevalence of antibodies against HSV-2 among Yukpa natives in Venezuela.

[Effect of climatic factors on the epidemiology of rotavirus infection in children under 5 years of age in the city of Maracaibo, Venezuela]

Diarrhea is one of the most common problem of public health worldwide, specially in developing countries. In Venezuela, this affection must be weekly reported when it occurs in children under five years of age. During June 1993 to May 1995, 379 stool specimens were obtained from children under five years of age with diarrhea admitted in Hospital de Niños of Maracaibo, Venezuela. Control group was conformed by 93 asymptomatic children. The rotavirus RNA was extracted with phenol-chloroform and precipitated with ethanol. Finally, polyacrylamide-gel-electrophoresis (PAGE), followed by silver staining was employed for rotavirus detection. Our results showed 62 (16.4%) positive cases for rotavirus in symptomatic children and 9 (9.7%) in control group. The highest incidence was showed in the infants under one year of age (21.5%). The electrophoretic analysis revealed only one long electropherotype pattern in studied samples. It was observed a close relationship between the increase of rotavirus cases and the increase of the pluviometric index and a decrease of mean temperature observed during the period of study. Both variables determine the increase or decrease of viral infection in our region. This result shows the importance of the climatic factors in the rotavirus epidemiology.

Peripheral nerve soluble esterases are spontaneously reactivated after inhibition by paraoxon: implications for a new definition of neuropathy target esterase

Soluble extracts of chicken peripheral nerve contain detectable amounts of phenyl valerate esterase (PVase) activity (about 2000 nmol/min per g of fresh tissue). More than 95% of this activity is inhibited in assays where substrate has been added to a preincubated mixture of tissue with the non-neuropathic organophosphorus compound (OP) paraoxon (O,O'-diethyl p-nitrophenyl phosphate): residual activity includes soluble neuropathy target esterase (S-NTE) which, by definition, is considered resistant to long-term progressive (covalent) inhibition by paraoxon. However we have previously shown that paraoxon strongly interacts with S-NTE so interfering with its sensitivity to other inhibitors. We now show that, surprisingly, removal of paraoxon by ultrafiltration ('P' tissue) in order to avoid such an interference results in the reappearance of about 65% of total original soluble PVase activity which is inhibited in the presence of this OP. Although a purely reversible non-progressive inhibition might be suspected, kinetic analysis data show a time-progressive inhibition which suggests that such PVase(s) covalently bind paraoxon. Also a time-dependent recovery due to spontaneous reactivation of the PVase activity was observed after dilution of the inhibitor. Gel filtration chromatography of 'P' tissue in Sephacryl S-300 shows that the reactivated activity is associated with proteins of about 100-kDa mass which include S-NTE and an, as yet, unknown number of other PVases. The implications of these findings in the definition of NTE in a target tissue for the so-called organophosphorus-induced delayed polyneuropathy (OPIDP) are discussed.

Carrier-dependent suppression of the anti-phosphorylcholine plaque-forming cell response in Trichinella-infected mice is mediated by anti-hapten IgG1 antibodies

In normal mice, the phosphorylcholine(PC)-bearing Trichinella spiralis antigen FCp induces PC-specific IgM antibodies. Infection with T. spiralis appears to suppress this response, without affecting the production of anti-PC antibodies in response to other PC-bearing antigens; the suppression can thus be considered carrier-dependent. Previous work in our laboratory has indicated that the observed suppression is due to a soluble factor present in the serum of infected mice. In the work reported here, we investigated the identity of this factor. After in vitro stimulation with FCp, spleen cells from FCp-primed infected mice showed a stronger anti-PC IgM response than spleen cells from FCp-primed uninfected mice, confirming that cell memory for FCp is unimpaired by infection. Passive transfer of serum from infected mice to normal recipients, followed by immunization of recipients with FCp or another thymus-dependent or thymus-independent PC-bearing antigen, confirmed that the suppressive agent is soluble and that its activity is carrier-dependent. The suppressive agent was retained by immunoaffinity chromatography with PC or rabbit anti-mouse Ig as ligand, showing that it is a PC-specific Ig. Gel filtration of the fractions retained by PC-immunoaffinity, and subsequent identification of Ig isotypes by an ELISA-based procedure, indicated that the suppressive Igs are of the IgG1 isotype. These findings may be relevant for understanding antibody-mediated down-regulation of the immune response.

The role of opsonization by antibody and complement in in vitro phagocytosis of microsporidian parasites by turbot spleen cells

We investigated the role played by opsonization by antibody and complement in in vitro phagocytosis of microsporidian spores by turbot adherent phagocytes. Most turbot adherent cells displaying phagocytic activity are probably macrophages. Phagocytosis of yeast cells and polystyrene beads was greatly enhanced in the presence of both the Ig and the non-Ig (i.e. complement-containing) fractions of normal turbot serum, but phagocytosis of Glugea caulleryi or Tetramicra brevifilum spores was not affected by either fraction. Neither anti-G. caulleryi immune serum, nor anti-T. brevifilum immune serum (which cross-reacted considerably with G. caulleryi antigens), enhanced phagocytosis of G. caulleryi spores. Finally, spores treated with sodium m-periodate (to modify the structure of surface-borne sugars) were less effectively ingested than untreated spores, suggesting that phagocytosis of microsporidian spores involves recognition of such sugars by the phagocytic cell. The results of this study support the hypothesis that microsporidian parasites of fish in some way modulate the host phagocytic responses.

A sandwich immunoassay to quantify low levels of turbot (Scophthalmus maximus) immunoglobulins

We have developed an enzyme-linked immunosorbent assay for the quantification of turbot (Scophthalmus maximus) immunoglobulin (Ig). The capture antibody is a rabbit polyclonal antiserum to turbot Ig, and the detector antibody a monoclonal antibody (UR3) to the turbot Ig heavy chain. Both antibodies bind nearly 100% of turbot Ig. The assay allows detection of turbot Ig in serum at concentrations as low as 0.16 micrograms ml-1 and takes less than 4 h. Precision is satisfactory, with intra-assay coefficients of variation (CVs) ranging from 2.1 to 16.6%, and inter-assay CVs ranging from 5.8 to 24.6%. We used the assay to determine Ig concentrations in the sera of healthy turbot of different weights. Mean serum Ig concentration was 3.35 +/- 0.74 mg ml-1 for fish weighing 15-25 g and 11.14 +/- 1.87 mg ml-1 for fish weighing 1000-2000 g.

Manganese toxicity: muscarinic receptor binding in the mouse brain

In the present study we determined the effect of repeated administration of manganese chloride on the binding parameters of [3H]quinuclidinyl benzilate (3H-QNB) in striatum, frontal cortex, and hippocampus of mice. Daily intraperitoneal injections of manganese chloride (5 mg Mn/kg) 5 d/wk during 9 wk did not alter the receptor density (Bmax) and the dissociation constant (Kd) of 3H-QNB in the different brain regions studied. These results suggest that chronic treatment with manganese does not affect the binding characteristics of 3H-QNB to the cholinergic muscarinic receptors in mouse brain.

Monoclonal antibodies to turbot (Scophthalmus maximus) immunoglobulins: characterization and applicability in immunoassays

Five monoclonal antibodies (mAbs) to immunoglobulins (Igs) of the turbot Scophthalmus maximus were produced and characterized. All the mAbs (denominated UR1, UR3, UR4, UR6 and UR7) are of isotype IgG1/kappa and show good anti-turbot Ig reactivity in enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results of competitive ELISA and immunoblotting analysis indicate that these five mAbs react with at least three different epitopes on the turbot Ig H chain. Except in the case of UR1, reactivity with periodate-treated purified turbot Ig was much lower than with the untreated Ig, suggesting that carbohydrate residues are involved in epitope recognition. All the mAbs showed reactivity with sera from the closely related species Scophthalmus rhombus but not with sera from species of other flatfish genera. One of these mAbs (UR3) has been successfully applied for the detection of antibodies against Vibrio anguillarum in ELISA.

[Molecular epidemiology of subgroups and serotypes of rotavirus in children less than 4 years of age in the city of Maracaibo with a diarrheal syndrome]

Between november 1989 and january 1991, two hundred stool samples were obtained from children under 4 years of age, hospitalized with diarrhea. Sixty stool samples from apparently healthy children were used as controls. Rotavirus infections were diagnosed in 28 (14%) specimens using two enzyme immunoassays, (Abbott Laboratories' kit and monoclonal antibodies). PAGE, ELISA and PCR were used to determine electropherotypes, subgroups and serotypes respectively. The study of electropherotypes detected two migration patterns: a short one in 4 samples (14.3%) and a long pattern in 16 cases (57.1%). These results were verified by a specific subgroup monoclonal antibodies ELISA. The polymerase chain reaction showed that serotype 1 accounted for 46.4% of positive samples, while serotypes 3 and 4 present in 3.6% and 7.4% of the specimens respectively. Serotype 2 was not detected and 42.8% samples were untypable. Males between 0 and 12 months of age were the most affected. There was no correlation between human rotavirus serotypes, subgroups and electropherotypes, and age of the patients. All detected genetic variants were present in children under two years of age.

Serum ferritin deficiency in Huntington's disease patients

This study was designed to investigate serum levels of iron, ferritin, vitamin B12 and folic acid in 18 Huntington's disease patients and 86 healthy control subjects. Serum iron, vitamin B12 and folic acid levels were normal. Ferritin concentrations were significantly diminished in the choreic patients. The importance of this finding in our attempt to understand the underlying biochemical defect and the chemical nature of the iron deposits found in several brain nuclei in Huntington's disease patients is unknown.

Nutritional evaluation of Huntington disease patients

A nutritional survey and evaluation was made in Huntington disease patients by the 24-h-recall method. Control subjects and choreic patients consumed a diet that supplied all the essential amino acids. The diet was hypocaloric, rich in animal protein, and low in fat and carbohydrates. The ratio of calcium to phosphorus in the groups studied was less than 1. High vitamin A and low vitamin C and niacin intakes were observed in Huntington disease patients. Only 17% of control subjects showed weight deficiency; 55% of the patients at stages III and IV of the disease were malnourished despite receiving the same food intake as controls. Although iron intake was deficient in all groups studied, it was enough to maintain normal serum levels of this metal. The deficiencies found in some nutrients do not explain the clinical manifestations observed in Huntington disease patients.

Changes in serum and striatal free amino acids after Venezuelan equine encephalomyelitis virus infection

The infection with the Venezuelan equine encephalomyelitis virus produced a significant increase in the concentration of alanine, arginine, asparagine, glutamine, isoleucine, leucine, methionine, phenylalanine, threonine, tryptophan, tyrosine, and valine in the striatum of rats. On the contrary, the concentrations of aspartate, GABA, glutamate, and taurine were reduced. Arginine, aspartate, glycine, methionine, phenylalanine, taurine, and tyrosine concentrations were increased in the serum of infected rats. However, the modifications in the content of free amino acids in the striatum and serum of rats that survived the infection were qualitatively and quantitatively different from those detected during the acute phase of the infection.

Free amino acids in the striatum of mice infected with Venezuelan equine encephalomyelitis virus

In mice inoculated with the Guajira strain of Venezuelan equine encephalomyelitis virus, a significant increase in the concentration of arginine, isoleucine, leucine, glycine, phenylalanine, serine, threonine, and valine was produced in the striatum. On the contrary, the levels of alanine, asparagine, aspartate, GABA, glutamine, and taurine were reduced. No changes were observed in the striatal content of tyrosine and glutamic acid.

Os odontoideum removed by a transoral approach

A case of atlanto-axial dislocation secondary to the presence of an "Os Odontoideum" is reported in which there was no history or evidence of trauma before the onset of symptoms. The treatment of this unusual clinical condition is discussed.