Synthesis and Biochemical Evaluation of Samarium-153 Oxide Nanoparticles Functionalized with iPSMA-Bombesin Heterodimeric Peptide.

Developments in the design of lanthanide oxide nanoparticles (NPs) have unleashed a wide variety of biomedical applications. Several types of hepatic cancer cells overexpress two proteins: the gastrin-releasing peptide receptor (GRPr), which specifically recognizes the bombesin (BN) peptide, and the prostate-specific membrane antigen (PSMA), which specifically binds to several peptides that inhibit its activity (iPSMA). This research synthesized and physicochemically characterized Sm2O3 nanoparticles functionalized with the iPSMA-BN heterodimeric peptide and studied the effects on their structural, biochemical and preclinical properties after activation by neutron irradiation for possible use in molecular dual-targeted radiotherapy of hepatocellular carcinoma. The Sm2O3 NPs were synthesized by the precipitation-calcination method and functionalized with iPSMA-BN peptide using the DOTA macrocycle as a linking agent. Analysis of physicochemical characterization via TEM, EDS, XRD, UV-Vis, FT-IR, DSL, and zeta potential results showed the formation of Sm2O3-iPSMA-BN NPs (94.23 ± 5.98 nm), and their physicochemical properties were not affected after neutron activation. The nanosystem showed a high affinity with respect to PSMA and GRPr in HepG2 cells ( Kd = 6.6 ± 1.6 nM) and GRPr in PC3 cells ( Kd = 10.6 ± 1.9 nM). 153Sm2O3-iPSMA-BN NPs exhibited radioluminescent properties, making possible in vivo optical imaging of their biodistribution in mice. The results obtained from this research support further preclinical studies designed to evaluate the dosimetry and therapeutic efficacy of 153Sm2O3-iPSMA-BN nanoparticles for in vivo imaging and molecular dual-targeted radiotherapy of liver tumors overexpressing PSMA and/or GRPr proteins.

Synthesis, chemical and biochemical characterization of Lu2O3-iPSMA nanoparticles activated by neutron irradiation.

Among the nanomaterials, rare sesquioxides (lanthanide oxides such as Lu2O3) are of interest due to their adequate thermal conductivity, excellent chemical stability, and high light output. The prostate-specific membrane antigen (PSMA) is an integral multifunctional protein overexpressed in various types of cancer cells. The radiolabeled PSMA inhibitor peptides (iPSMA) have demonstrated their usefulness as specific probes in the treatment and detection of a wide variety of neoplasms, mainly due to their high in vivo recognition by the PSMA protein. The objective of this research was to synthesize Lu2O3-iPSMA nanoparticles (NPs) and characterize their physicochemical properties before and after neutron activation, as well as to assess their biodistribution profile and in vitro potential to target cells overexpressing PSMA. The Lu2O3 NPs were synthesized by the precipitation-calcination method and conjugated to the iPSMA peptide using DOTA (1,4,7,10-tetraazocyclodecane-N,N',N″,N‴-tetraacetic acid) as a linking agent. Results of the physicochemical characterization by FT-IR and UV-Vis spectroscopies, SEM, TEM, DLS, HRTEM, SAED, DSC-TGA, and X-ray diffraction indicated the formation of Lu2O3-iPSMA NPs (diameter of 29.98 ± 9.07 nm), which were not affected in their physicochemical properties after neutron activation. 177Lu2O3-iPSMA NPs showed high affinity (Kd = 5.7 ± 1.9 nM) for the PSMA protein, evaluated by the saturation assay on HepG2 hepatocellular carcinoma cells (PSMA-positive). The biodistribution profile of the nanosystem in healthy mice showed the main uptake in the liver. After irradiation, radioactive Lu2O3-iPSMA NPs exhibited radioluminescent properties, making the in vivo acquisition of their biodistribution, via optical imaging, possible. The results obtained from this research validate the execution of additional preclinical studies with the objective of evaluating the potential of the 177Lu2O3-iPSMA NPs for the targeted radiotherapy and in vivo imaging of tumors overexpressing the PSMA protein.

Control of tight junctional sealing: roles of epidermal growth factor and prostaglandin E2.

Epithelia can adjust the permeability of the paracellular permeation route by regulating the degree of sealing of the tight junction. This is reflected by a transepithelial electrical resistance (TER) ranging from a few tenths to several thousand ohms times square centimeters, depending on the difference in composition between the fluid in the lumen and the interstitial fluid. Although teleologically sound, such correlation requires a physiological explanation. We have previously shown that urine extracts from different animal species increase the TER of Madin-Darby canine kidney (MDCK) monolayers and that these effects are mediated by epidermal growth factor (EGF) contained in the flowing intratubular fluid that eventually reaches the urine. This increase in TER is accompanied by an enhanced expression of claudin-4 (cln-4) and a decrement of cln-2. These changes are transient, peaking at approximately 16 h and returning to control values in approximately 24 h. In the present work we investigated how EGF provokes this transient response, and we found that the activation of extracellular-regulated kinases 1/2 (ERK1/2) by EGF is essential to increase TER and cln-4 content, but it does not appear to participate in cln-2 downregulation. On the other hand, prostaglandin synthesis, stimulated by EGF, functions as a negative feedback, turning off the signal initiated by EGF. Thus, PGE(2) blocks ERK1/2 by a mechanism that involves the G alpha(s) protein, adenylyl cyclase as well as protein kinase A in MDCK cells. In summary, the permeability of a given segment of the nephron depends on the expression of different claudin types, which may be modulated by EGF and prostaglandins.

Transitional cardiac cells of the conductive system of the dog heart. Distinguishing morphological and electrophysiological features.

Cardiac cells with distinctive electrophysiological and morphological features were found at the junctional region between Purkinje and ventricular cells of the dog heart. The electrophysiological exploration of these "transitional" cells revealed action potentials markedly different in configuration from those generated by Purkinje or by ventricular cells. The impaled cardiac cells which generated transitional action potentials were identified in serial sections and studied with the light and the electron microscopes. The transitional cells were found to be characterized cytologically by: (a) their subendocardial location, (b) their small diameter, (c) the absence of T system and sarcoplasmic reticulum, and (d) the lack of intercalated discs under the light microscope and the sparsity of specialized intercellular junctions under the electron microscope. Purkinje, transitional, and ventricular cells were found to be joined by gap junctions permeable to lanthanum. A quantitative difference in the extent and distribution of specialized intercellular junctions may be one of the factors responsible for the slow velocity of conduction characteristic of the Purkinje-ventricular junctional region.

Selective deposition of lanthanum in mammalian cardiac cell membranes. Ultrastructural and electrophysiological evidence.

Perfusion of beating false tendons of the dog heart with ionic lanthanum produced drastic but reversible modifications of the excitability and the transmembrane action potential of Purkinje cells. Ultrastructural examination of these cells revealed the appearance of a fine extracellular precipitate detectable on unstained sections. In addition, specimens perfused with La(+++) showed a striking increase in the contrast of the sarcolemma, particularly in gap junctions and in pinocytic vesicles. La(+++) deposits were restricted to the cytoplasmic leaflets of the sarcolemma; no precipitates were found at the plasma membrane of fibroblasts, endothelial and smooth muscle cells, or unmyelinated nerve fibers present in the same specimens. A selective deposition of La(+++) was also observed in the sarcolemma of atrial and ventricular cells of dog, rabbit, and cat hearts, as well as in the membrane of the transverse tubular system of ventricular cells. Both the electrophysiological effects and the ultrastructural membrane deposits produced by La(+++) disappeared when the specimens were subsequently perfused with phosphate-containing tyrode solution. These results tend to demonstrate that a distinctive feature of the sarcolemma of mammalian cardiac cells is the presence of regions with a high surface density of binding sites for polyvalent cations.

Development of fluorogenic probe-based PCR assays for the detection and quantification of bovine piroplasmids.

This paper reports two new quantitative PCR (qPCR) assays, developed in an attempt to improve the detection of bovine piroplasmids. The first of these techniques is a duplex TaqMan assay for the simultaneous diagnosis of Babesia bovis and B. bigemina. This technique is ideal for use in South America where bovids harbour no theilerids. The second technique, which is suitable for the diagnosis of both babesiosis and theileriosis worldwide, involves fluorescence resonance energy transfer (FRET) probes. In FRET assays, Babesia bovis, B. divergens, Babesia sp. (B. major or B. bigemina), Theileria annae and Theileria sp. were all identifiable based on the melting temperatures of their amplified fragments. Both techniques provided linear calibration curves over the 0.1fg/microl to 0.01ng/microl DNA range. The assays showed good sensitivity and specificity. To assess their performance, both procedures were compared in two separate studies: the first was intended to monitor the experimental infection of calves with B. bovis and the second was a survey where 200 bovid/equine DNA samples from different countries were screened for piroplasmids. Comparative studies showed that duplex TaqMan qPCR was more sensitive than FRET qPCR in the detection of babesids.

A quantitative PCR assay for the detection and quantification of Babesia bovis and B. bigemina.

The haemoparasites Babesia bovis and Babesia bigemina affect cattle over vast areas of the tropics and temperate parts of the world. Microscopic examination of blood smears allows the detection of clinical cases of babesiosis, but this procedure lacks sensitivity when parasitaemia levels are low. In addition, differentiating between similar haemoparasites can be very difficult. Molecular diagnostic procedures can, however, overcome these problems. This paper reports a quantitative PCR (qPCR) assay involving the use of SYBR Green. Based on the amplification of a small fragment of the cytochrome b gene, this method shows both high sensitivity and specificity, and allows quantification of parasite DNA. In tests, reproducible quantitative results were obtained over the range of 0.1 ng to 0.1 fg of parasite DNA. Melting curve analysis differentiated between B. bovis and B. bigemina. To assess the performance of the new qPCR procedure it was used to screen for babesiosis in 40 cows and 80 horses. B. bigemina was detected in five cows (three of these were also found to be positive by standard PCR techniques targeting the 18S rRNA gene). In addition, B. bovis was detected in one horse and B. bigemina in two horses using the proposed method, while none was found positive by ribosomal standard PCR. The sequences of the B. bigemina cytochrome b and 18S rRNA genes were completely conserved in isolates from Spain and Argentina, while those of B. bovis showed moderate polymorphism.

Occurrence of antibodies against Neospora caninum in water buffaloes (Bubalus bubalis) on four ranches in Corrientes province, Argentina.

The aim of the present work was to describe the occurrence of antibodies to Neospora caninum in water buffaloes on four ranches located in Corrientes province in the northeast of Argentina. Antibodies against N. caninum were determined in sera of 449 water buffaloes by using an indirect fluorescent antibody test (IFAT). A Bayesian logistic regression mixed model was used to quantify the strength of association between positive serological results to N. caninum and gender, age and category (calf, steer, heifer, cow) as risk factors. Antibody titers were found in 287 (64%) buffaloes. All ranches had seropositive animals. Age was more strongly associated with positive results to N. caninum (OR: 1.4; CI 95%: 0.86-2.22) than gender (OR: 1.02, CI 95%: 0.40-2.59) and category (OR: 0.88, CI 95%: 0.57-0.88). Results suggest a high exposure of water buffaloes to N. caninum by postnatal transmission in these four ranches located in Corrientes province, Argentina. Further studies are needed to quantify the consequences of Neospora-infections in the water buffalo industry.

Sex-Dependent Effects of Prenatal Stress on Social Memory in Rats: A Role for Differential Expression of Central Vasopressin-1a Receptors.

Prenatal stress (PNS) affects a number of traits in the offspring, including stress axis regulation, emotionality and cognition; however, much less is known about the effects of PNS on social memory and the underlying central mechanisms. In the present study, we investigated social preference, social memory under basal and stress conditions and olfactory memory for social and nonsocial odours in the adult offspring of dams exposed to social stress during late pregnancy. Given the key roles that the central oxytocin and vasopressin systems play in facilitating social memory, we further investigated the effects of PNS on the central expression of mRNA for oxytocin (Oxtr) and vasopressin-1a (Avpr1a) receptors. PNS did not affect social preference in either sex; however, social memory was impaired under basal conditions in PNS females but not PNS males. Accordingly, Avpr1a mRNA expression in the lateral septum and bed nucleus of stria terminalis (BNST) was unaltered in males but was significantly lower in PNS females compared to controls. No differences in Oxtr mRNA expression were detected between control and PNS offspring in either sex in any of the brain regions examined. Social memory deficits in PNS females persisted when social odours were used; however, this does not appear to be a result of impaired olfaction because memory for nonsocial odours was similar in control and PNS females. Under acute stress conditions, deficits in social memory were observed in both male and female control offspring; however, PNS males were unaffected. Moreover, acute stress facilitated social memory in PNS females and this was associated with an up-regulation of Avpr1a mRNA in the lateral septum and BNST. Our data support a role for altered signalling via central Avpr1a in PNS-induced sex-dependent changes in social memory and may have implications for understanding the aetiology of neurodevelopmental disorders characterised by social behaviour deficits in humans.

Physical and Psychosocial Functions of Adults with Lower Limb Congenital Deficiencies and Amputations in Childhood.

Objectives. (1) To describe the epidemiological and medical features of a sample with LLA and LLD in childhood and (2) to explore their relationship with subsequent physical and psychosocial functions in adulthood. Methods. Cross-sectional survey. Demographics, medical data, Locomotor Capabilities Index (LCI), and Discomfort-Engagement in Everyday Activities Involving Revealing the Body Scale (D-EEARB) were collected from thirty-two adults who suffered from LLA in childhood or LLD. Results. Most of the sample (53.1% males) was working (84.4%), living independently (75%), and single (75%). Mean age was 33.16 (SD = 7.64, range 18-50). Leading causes for LLA were traumatic (40.6%) and oncologic (25%). LLD was present in 6 cases (18.8%). LCI scores revealed a high performance among males (t 17,464 = 2.976, p = .008). D-EEARB scores showed that 56.25% stated feeling "quite" or "totally comfortable" in situations which involved revealing their body, but 43.75% stated the contrary ("uncomfortable" or "very uncomfortable"). LLD and traumatic LLA show higher scores in D-EEARB than vascular and oncological LLA (χ (2) = 7.744, df = 3, p = .05). Conclusions. Adults suffering from LLDs and LLAs during childhood seem to perform well once they are adults. However, 43.75% of patients express considerable discomfort in situations that involve revealing the body.

Haemodynamic effects of increasing angle of head up tilt.

OBJECTIVE: To investigate the haemodynamic effects of varying the angle of head up tilt. METHODS: 20 healthy subjects (12 female, eight male; mean (SD) age 33.6 (8.4) years) underwent head up tilt for five minutes to each of four angles of tilt in random order, with a five minute rest period at the horizontal between each angle. Forearm blood flow was measured using intermittent occlusion mercury strain gauge plethysmography at two and five minutes. Subjects underwent continuous monitoring of heart rate, systolic blood pressure (SBP), and diastolic blood pressure (DBP) by Finapres and cardiac output and stroke volume by impedance cardiography. Each variable was measured at two and five minutes, averaged over the period of blood flow measurement. RESULTS: Every haemodynamic variable at each angle was significantly different from supine values. Head up tilt produced progressive increases in heart rate (11-21%), SBP (12-21%), and DBP (20-33%) with increasing tilt angle. However, although 45 degrees produced significantly less haemodynamic effect, there were no significant differences for angles between 60 degrees and 90 degrees. Cardiac output fell on head up tilt by 17-20% and stroke volume by 28-34%, but increasing tilt angle produced no significant additional reduction in cardiac output and stroke volume because of increases in heart rate and vasoconstriction. CONCLUSIONS: Angles < 60 degrees produce significantly less haemodynamic effects than steeper angles. Increasing tilt angle beyond 60 degrees produces no apparent additional effect on cardiac output or sympathetic tone. Increasing tilt angle beyond 60 degrees confers no additional orthostatic stress and may not affect the sensitivity and specificity of head up tilt testing as previously thought. Sixty degrees of tilt is a more practical angle for support of a syncopal patient and is recommended.

Two preferential conducting pathways within the bundle of His of the dog heart.

An isolated preparation formed exclusively of the specific conducting tissue of the A. V. node, bundle of His and bundle branches was dissected from the dog heart and studied using the microelectrode technique. The preparation, being completely isolated from the normal neighboring conducting tissues, can be turned over or twisted, so as to stimulate and record either separately or simultaneously the electrical activity of the dorsal and ventral surfaces of the bundle of His. The preparation showed spontaneous activity and maintained its physiological properties for long periods of time. Morphological and electrophysiological evidence was found to differentiate two functional strands within the common trunk of the bundle of His. These two strands appear in different planes: The anterior or ventral strand starts in the superior part of the atrioventricular node and continues to form the right bundle branch; the posterior or dorsal strand begins in the inferior part of the A. V. node and runs underneath the ventral strand to form later the left bundle branch. The two strands can be separated from each other so as to have two functional preparations: one formed of the superior part of the A. V. node, the anterior strand and the right bundle branch; the other constituted by the inferior part of the A. V. node, the posterior strand and the left bundle branch. Some of the electrophysiological properties of both strands are similar, except for the conduction velocity, which appears to be faster in the posterior strand than in the anterior. Transversal propagation occurs between the two strands and is slower than the longitudinal propagation that takes place along the parallel fibers of each strand. The presence of cellular transversal bridges between the strands assures the activation of the two strands as if they were a single conducting cable. These characteristics are discussed in relation to some disturbances in propagation.

Specific immune response to Parietaria judaica plant profilin: a low T cell proliferative response supports high IgE and skin prick test.

BACKGROUND: allergic disease caused by Parietaria judaica (Pj) has been widely documented in Mediterranean area. Profilins have been identified as widely distributed allergenic proteins. The role of Pj profilin in specific immune response in Pj-sensitized patients is unknown. METHODS: skin prick test and determination of specific and total IgE levels in serum were performed in all patients (n = 28) and non-allergic controls (n = 18). Peripheral blood mononuclear cells (PBMC) were isolated from both groups and stimulated with crude extract or highly purified Pj profilin. The production of type I and type II cytokines was determined by specific and polyclonal stimuli in patients and controls. T-cell lines specific to Pj profilin were established and cross-reactivity with another highly purified profilin from Phleum pratense (Phl p) was evaluated. RESULTS: Pj profilin-sensitized patients showed a small but significantly increased in T-cell proliferative response to this profilin compared with non-atopic controls. The production of interleukin (IL)-4 and interferon (IFN)-γ in response to the specific stimulus was undetectable. However, the production of IL-4 in response to a polyclonal stimulus [phytohemagglutinin (PHA)] was significantly higher in atopic patients than in controls. The T-cell response did not correlate with the magnitude of response to skin prick tests with Pj profilin or with Pj-specific serum IgE levels. In addition, the production of IL-4 in response to a polyclonal stimulus (PHA) did not correlate with the individual skin prick tests to Pj profilin or with Pj-specific IgE levels in serum. The T-cell lines tested showed no cross-reactivity with Phl p profilin. CONCLUSIONS: our results suggest that Pj profilin is partly responsible for the T-cell-mediated response in patients allergic to Pj. The high skin reactivity to Pj profilin is these patients was accompanied by a small increase in the T-cell response to this profilin. The response was highly specific since Pj profilin specific T-cell lines showed no cross-reactivity with a highly homologous profilin from Phl p. The lack of correlation between the proliferative T-cell response and polyclonal IL-4 production with allergen-specific serum IgE and skin reactivity probably indicates that some of the responding T-cells may be involved in immune reactions other than those supporting IgE production.

The use of the Hilbert transform in ECG signal analysis.

This paper presents a new robust algorithm for QRS detection using the first differential of the ECG signal and its Hilbert transformed data to locate the R wave peaks in the ECG waveform. Using this method, the differentiation of R waves from large, peaked T and P waves is achieved with a high degree of accuracy. In addition, problems with baseline drift, motion artifacts and muscular noise are minimised. The performance of the algorithm was tested using standard ECG waveform records from the MIT-BITH Arrhythmia database. An average detection rate of 99.87%, a sensitivity (Se) of 99.94% and a positive prediction (+P) of 99.93% have been achieved against study records from the MIT-BITH Arrhythmia database. A detection error rate of less than 0.8% was achieved in every study case. The reliability of the proposed detector compares very favorably with published results for other QRS detectors.

[Dietary habits of 2 populations of the province of Barcelona (I): design and validation of a semiquantitative questionnaire of frequency of food consumption]. / Hábitos alimentarios de dos poblaciones de la provincia de Barcelona (I): Diseño y validación de un cuestionario semicuantitativo de frecuencia de consumo de alimentos.

BACKGROUND: The identification of associations between alimentary factors and specific chronic diseases has led to the development of valid diet measurement methods. In the present article the design and validation of a questionnaire on the frequency of food consumption is reported. METHODS: From an initial sample of 1,034 inhabitants of two populations in the province of Barcelona, Spain, a sample stratified by age, sex and population of 64 individuals between 13-70 years of age was randomly selected. A semiquantitative questionnaire was initially given to 58 of the 64 subjects including 39 foods or groups of food and these were instructed as to how to follow a registry of food for 7 days in two different periods. The intakes of energy products, macronutrients, fiber, cholesterol and vitamins C, A and E were estimated by the two methods were compared. RESULTS: The means of nutrients estimated were lower in the questionnaire than those obtained by the reports of foods with the exception of the intake of carbohydrates. The range of the correlation coefficients for the values obtained by both methods was of 0.17 for vitamin E and 0.54 for the monounsaturated fatty acids which, after correction for the alternation factor, were found to be 0.20 and 0.67, respectively. Thirty-nine percent of the individuals were classified within the quintile of low consumption with 33% being within the quintile of greatest consumption. CONCLUSIONS: The use of a semiquantitative questionnaire may be useful to describe the dietary habits in a given population and fundamentally when the population studied is to be classified according to the normal consumption of energy and macronutrients.

[Dietary habits of 2 populations of the province of Barcelona (II): comparative study of the frequency of consumption in both populations and its relationship to recommended diet in diabetes]. / Hábitos alimentarios de dos poblaciones de la provincia de Barcelona (II): Estudio comparativo de la frecuencia de consumo en ambas poblaciones y su relación con la dieta recomendada en la diabetes.

BACKGROUND: The aim of the present study was to compare the eating habits of two urban populations (Vilanova i la Geltrú and Gavá) of the province of Barcelona, Spain, and determine the relation with the diet recommended in diabetes since this diet does not differ from what is considered "equilibrated diet". METHODS: One thousand thirty-four individuals randomly selected from Primary Health Care Centers (PHCC) by a systematic sampling of all the outpatient consultations over one year to whom a questionnaire on semiquantitative frequencies were studied with the aim of determining their everyday diet. All those between 13 and 80 years of age, residing in the two municipalities studied and who attended the PHCC over the period of the study were included in the study. RESULTS: On comparison of both populations a statistically higher consumption (p < 0.01) of milk products, fish, vegetables, fruits and oils was observed in Vilanova i la Geltrú than in Gavá. Both groups presented a lower intake than recommended of fish, vegetables, and fruits. In contrast a high intake of sugar, ice cream and sugared beverages and foods were observed in the two populations studied and in the younger are groups. CONCLUSIONS: The population of Vilanova i la Geltrú have dietary habits which are closer to those recommended in the diet of diabetics than the population of Gavá.

[Epidemiology of children's intestinal parasitism in the Guadalquivir Valley, Spain]. / Epidemiología del parasitismo intestinal infantil en el Valle del Guadalquivir, España.

BACKGROUND: Intestinal parasitism represents a public health problem that should be periodically assessed in each region. In the present paper, a study about prevalence of intestinal parasites, has been carried out in children from the natural region of the Guadalquivir Valley. METHODS: During the period 1994-1996, 1,917 children without symptoms, aging between 6 and 10, were studied by means of coprological analysis and Graham method, all of them living in 20 villages in the Guadalquivir valley. RESULTS: The overall prevalence of intestinal parasitism have been of 27.12%. The reported parasites and their prevalence are as follows: Enterobius vermicularis (20.44%), Giardia lamblia (5.05%), Entamoeba coli (2.45%), Endolimax nana (1.61%), Entamoeba histolytica (0.31%), Entamoeba hartmanni (0.05%), Iodamoeba bütschlii (0.05%). CONCLUSIONS: The overall prevalence of intestinal parasites is similar to that found in other spanish region, if only a little bit more favourable probably due to the long lasting drought and the improvements in health resources, no geohelminths have been detected unlike other protozoan infections, giardiasis maintains a relatively high prevalence.

[Physical exercise and food habits: a study of adolescents in Cádiz]. / Ejercicio físico y hábitos alimentarios: un estudio en adolescentes de Cádiz.

BACKGROUND: A increased number of eating disorders among teen-agers are currently being reported. Physical exercise, especially when done individually, is one of the methods chosen for losing weight. We are basing this study on the hypothesis of a larger number of eating habit disorders (EHD's) in subjects who do physical exercise alone. This study describes and compares eating habits among teen-agers that do individual exercise as opposed to athletes who work out in groups or on teams. METHOD: Cross-section study of 532 teen-agers ages 14-18 who are enrolled in school and who do physical exercise, having been selected at random by means of a two-stage, stratified sampling process. The subjects were divided into two groups according whether they did individual physical exercise alone (Number: 216) or in groups (Number: 316). The eating habits of both groups were analyzed based on a questionnaire filled out by the subjects themselves. RESULTS: In the group preferring individual sports, females were predominant (degree of males 0.44). Of these females, their being on diets in order to lose weight was 3.12 times more frequent, compulsive eating episodes being 3.73 times more frequent. As regards behaviors which might be considered to be compensatory, there is a clear concentration thereof among those who do sports individually, hence 43% stated to voluntarily undergo periods of fasting (4.96 times more than those who exercise in groups), 46% stating to have brought on vomiting at one time or another for "dieting" purposes (3.76 more) and up to 26% have used laxatives with the intention of losing weight (2.56 times more than among athletes who play on teams). CONCLUSION: The existence of EHD's seems to be associated with teen-agers who play individual sports as opposed to those who play on teams.

[The stability of solid food labeled with different radiopharmaceuticals for studying gastric emptying]. / Estabilidad de alimento sólido marcado con diferentes radiofármacos para vaciamiento gástrico.

OBJECTIVE: Sulfur colloid 99mTc-SC, the radiopharmaceutical of choice for solid gastric emptying studies, is not available in our country. It has led us to assess the solid binding stability of seven alternative radiopharmaceuticals that could present adequate fixation to it a priori. MATERIALS AND METHOD: The stability of labelled solid food with seven colloidal 99mTc-radiopharmaceuticals of different sizes and nature (MAA, tin colloid, rhenium sulphide macrocolloid, albumin microcolloid, sulfur nanocolloid, albumin nanocolloid and rhenium sulfur nanocolloid) has been studied by measuring their dissociated activity after two hours digestion in simulated gastric fluid (kept 120' in agitation, in HCl 0.1 M at 37). The survey also assesses radiopharmaceutical labelling stability after two hours digestion in identical conditions by measuring their radiochemical purity in ITLC. RESULTS: In these conditions, MAA, rhenium sulphide macrocolloid, albumin microcolloid and albumin microcolloid present the best behaviour, with an activity linked to food over 90 % of the previously fixed activity. CONCLUSIONS: According to the results, there is no relationship between the radiopharmaceutical size and nature and the stability of its binding to the solid food. Because rhenium sulphide macrocolloid is no longer manufactured and the other three radiopharmaceuticals which have a binding stability to the solid food over 90 % do not include digestive explorations amongst their indications, nowadays, there is a serious legal limitation to carry out this type of studies in our country.

Evidence for extensive genetic diversity and substructuring of the Babesia bovis metapopulation.

Babesia bovis is a tick-transmitted haemoprotozoan and a causative agent of bovine babesiosis, a cattle disease that causes significant economic loss in tropical and subtropical regions. A panel of nineteen micro- and minisatellite markers was used to estimate population genetic parameters of eighteen parasite isolates originating from different continents, countries and geographic regions including North America (Mexico, USA), South America (Argentina, Brazil), the Middle East (Israel) and Australia. For eleven of the eighteen isolates, a unique haplotype was inferred suggesting selection of a single genotype by either in vitro cultivation or amplification in splenectomized calves. Furthermore, a high genetic diversity (H = 0.780) over all marker loci was estimated. Linkage disequilibrium was observed in the total study group but also in sample subgroups from the Americas, Brazil, and Israel and Australia. In contrast, corresponding to their more confined geographic origin, samples from Israel and Argentina were each found to be in equilibrium suggestive of random mating and frequent genetic exchange. The genetic differentiation (F(ST)) of the total study group over all nineteen loci was estimated by analysis of variance (Θ) and Nei's estimation of heterozygosity (G(ST')) as 0.296 and 0.312, respectively. Thus, about 30% of the genetic diversity of the parasite population is associated with genetic differences between parasite isolates sampled from the different geographic regions. The pairwise similarity of multilocus genotypes (MLGs) was assessed and a neighbour-joining dendrogram generated. MLGs were found to cluster according to the country/continent of origin of isolates, but did not distinguish the attenuated from the pathogenic parasite state. The distant geographic origin of the isolates studied allows an initial glimpse into the large extent of genetic diversity and differentiation of the B. bovis population on a global scale.