Análisis de los argumentos recibidos en la consulta pública para el etiquetado frontal de advertencia mexicano

OBJETIVO

Analizar los diferentes elementos en los argumentos recibidos durante la consulta pública del Proyecto de Modificación a la Norma Oficial Mexicana-051 (NOM-051), con énfasis en la protección de niñas, niños y adolescentes (NNA). Material y métodos. Se analizó la información de 1 095 argumentos, se identificó a los actores clave y se realizó un análisis de contenido para conocer la postura, a favor o en contra de los numerales relacionados con la protección a NNA. El análisis se hizo en el programa NVivo.

RESULTADOS

Se identificaron 781 actores clave. Durante la consulta pública se identificaron cuatro tácticas del sector privado para interferir en el proceso de la NOM-051: a) grupos fachada que enviaron comentarios en contra de la NOM-051; b) cuestionar la evidencia científica sobre la relación del consumo de edulcorantes y el desarrollo de obesidad en escolares; c) cuestionar la efectividad del uso del etiquetado de advertencia para edulcorantes; d) responsabilizar a los individuos de su enfermedad. Conclusión. La interferencia del sector privado en el proceso de implementación de la NOM-051 fue evidente en los argumentos enviados durante la consulta pública.

Digital food and beverage marketing appealing to children and adolescents: An emerging challenge in Mexico

BACKGROUND

Digital food marketing is increasing and has an impact on children's behaviour. Limited research has been performed in Latin America.

OBJECTIVES

To determine the extent and nature of Mexican children's and adolescents' exposure to digital food and beverage marketing during recreational internet use.

METHODS

A crowdsourcing strategy was used to recruit 347 participants during the COVID-19 lockdown. Participants completed a survey and recorded 45 minutes of their device's screen time using screen-capture software. Food marketing was identified and nutrition information for each marketed product was collected. Healthfulness of products was determined using the Pan-American Health Organization and the Mexican Nutrient Profile Model (NPM). A content analysis was undertaken to assess marketing techniques.

RESULTS

Overall, 69.5% of children and adolescents were exposed to digital food marketing. Most frequently marketed foods were ready-made foods. Children and adolescents would typically see a median of 2.7 food marketing exposures per hour, 8 daily exposures during a weekday and 6.7 during a weekend day. We estimated 47.3 food marketing exposures per week (2461 per year). The most used marketing technique was brand characters. Marketing was appealing to children and adolescents yet most of the products were not permitted for marketing to children according to the NPMs (>90%).

CONCLUSIONS

Mexican children and adolescents were exposed to unhealthy digital food marketing. The Government should enforce evidence-based mandatory regulations on digital media.

Perfil clínico y microbiológico de bacteremia primaria por Streptococcus pneumoniae en pacientes pediatricos hospitalizados a la red de atención terciaria Neumocolombia. 2017 – 2019

Objetivo: Describir las características clínicas, microbiológicas y los desenlaces de las bacteriemias primarias por S. pneumoniae ocurridas en población pediátrica hospitalizada en instituciones de alta complejidad, pertenecientes a la Red Neumocolombia (2017-2019). Metodología: Estudio observacional, descriptivo, longitudinal, exploratorio con alcance analítico, en donde se tomó información de las historias clínicas con hemocultivos positivos para S. pneumoniae sin otro foco infeccioso, realizados en los hospitales pediátricos, reportados a la Red Neumocolombia (2017-2019). Resultados: Durante el periodo de estudio se analizó información de 51 registros, 62,7% fueron hombres, la mediana de edad fue 25 meses (RIC 9-49). El síntoma predominante fue fiebre (78,4%), se reportó vacunación con Vacuna Neumocócica Conjugada decavalente (PCV-10) en 47%. El serotipo más frecuente fue 19A (39,4%). El porcentaje de resistencia antibiótica fue: eritromicina 43%, penicilina 25.4%, cefotaxima 11,7%. Los factores relacionados al ingreso a Unidades de Cuidado Intensivo Pediátrico (UCIP) fueron: dolor pleurítico (OR27,9; IC95%3,13 – 248,16 p=0,03), tos (OR6,04; IC95%1,46 – 24,88; p=0,013), dolor abdominal (OR 6,5; IC95%1,85 – 22,80; p=0,003), dificultad respiratoria (OR12; IC95%2,95 – 48,77 p=0,001), tirajes (OR22,71; IC95%4,65 – 141,90 p=0,001), cianosis (OR8,69; IC95%1,95 – 38,65 p=0,004), hipotermia (OR42,62; IC95%4,77 – 380,74 p=0,001), serotipo 19A (OR3,9;IC95%1,10 – 13,81 p=0,035). La letalidad fue del 11,7%. Conclusión: Después de la introducción de la vacuna PCV10 en Colombia en el año 2012 se reportaron cambios en la epidemiologia, con disminución de los serotipos vacunales, y aumento en el serotipo 19A, siendo uno de los factores que intervienen en el ingreso a UCIP por bacteriemia primaria. Se reporta aumento en la resistencia por eritromicina, penicilina y cefotaxima.

Low health-related quality of life in adult individuals with multiple limb deficiencies compared with population-based reference values

BACKGROUND

Knowledge on health-related quality of life (HRQoL) in multiple limb deficiencies (LDs) is limited.

OBJECTIVES

To investigate self-reported HRQoL in multiple LDs, assess differences between congenital LD and acquired LD and sex, and to evaluate associations between the types of LDs, demographic variables, and HRQoL.

STUDY DESIGN

Cross-sectional cohort study.

METHODS

A total of 106 individuals with multiple limb deficiencies treated at the EX-Center were invited by mail to fill out the Short Form-36 survey.

RESULTS

Responses from 62 participants, mean age ± SD 49.5 ± 14.2, showed that 43 had congenital LD and 19 had acquired LD. Responders reported reduced HRQoL in all Short Form-36 domains except Role-Emotional, compared with reference values (P < 0.05-<0.001). Individuals with a congenital LD reported worse Bodily Pain than acquired LD (P < 0.05), and women reported lower Physical Function than men (P < 0.05). Sick leave was negatively associated with physical composite score. Living in a rural area was positively associated with Mental Health (P < 0.01), and congenital LD was negatively associated with Vitality (P < 0.05).

CONCLUSIONS

Individuals with multiple LDs in Sweden have lower HRQoL compared with reference values. There are significant associations between sick leave and physical function, rural living and mental health, and the type of LD and vitality.

Molluscs community as a keystone group for assessing the impact of urban sprawl at intertidal ecosystems

Mollusc communities are getting endangered in the aftermath of urban sprawl because artificial structures do not surrogate natural substrates. In this study, we compared the diversity, community and trophic arrangements of molluscs among different models of artificial substrate and their adjacent natural rock, to detect relationships between some abiotic variables and the mollusc communities. Complexity, chemical composition and age were tested as potential drivers of the community. Diversity, community and trophic structure differed between natural and artificial substrates. Complexity at the scale of cm was detected as the most important factor driving the community structure. In addition, a chemical composition based on silica and/or scarce calcium carbonates seems to be relevant for molluscs, as well as for the secondary substrate where they inhabit. However, age did not seem to be a driving factor. Among the different artificial structures, macroscale complexity was detected as the main factor diverging a drastically poor community at seawall from other artificial structures. In this context, macro and microscale complexity, chemical composition and mineral type are variables to consider in future designs of artificial substrates.

Coastal armouring affects intertidal biodiversity across the Alboran Sea (Western Mediterranean Sea)

Intertidal ecosystems are key habitats that are being replaced by artificial hard substrates due to the increment of human activities in coastal areas. These new substrates host generally less biodiversity mainly due to differences in complexity and composition. This is a global phenomenon and has led to the development of strategies in the framework of eco-engineering. However, mitigating measures, such as new eco-designs, must cope with the high spatial variability of the region where they are applied. Therefore, in order to assess if differences in biodiversity detected at local scales in previous studies could be scaled up to predict patterns at a wider scale, we studied taxa richness and taxonomic structure of intertidal communities across the Alboran Sea (western Mediterranean Sea). We compared four different types of artificial substrates (cubes, rip-raps, seawalls and tetrapods) to assess which produces less impact. Overall, artificial substrates host low benthic biodiversity, specially on seawalls, whereas boulder-like artificial structures such as rip-raps were more similar to natural ones. Nevertheless, the effect of a particular type of artificial structure at a regional scale seems unpredictable, highlighting the challenge that eco-engineering measures face in order to establish global protocols for biodiversity enhancement and the importance of local scale in management programmes.

Effect of antimony in soils of an Sb mine on the photosynthetic pigments and antioxidant system of Dittrichia viscosa leaves

Antimony is a toxic element whose concentration in soil and water has been rising due to anthropogenic activities. This study focuses on its accumulation in leaves of Dittrichia viscosa growing in soils of an abandoned Sb mine, and the effect on oxidant/antioxidant systems and photosynthetic efficiency. The results showed leaves to have a high Sb accumulation capacity. The amount of total chlorophyll decreased depending on Sb concentration and of carotenoids increased slightly, with a consequent increase in carotenoid/chlorophyll ratio. Photosynthetic efficiency was unaffected. The amount of O ₂ ^.- rose, although there was no increase in cell membrane damage, with lipid peroxidation levels being similar to normal. This response may be due to considerable increases that were observed in total phenolics, PPO activity, and enzymatic antioxidant system. SOD, POX, and DHAR activities increased in response to increased Sb amounts in leaves. The ascorbate/glutathione cycle was also affected, with strong increases observed in all of its components, and consequent increases in total contents of the ascorbate and glutathione pools. However, the ratio between reduced and oxidized forms declined, reflecting an imbalance between the two, especially that between GSH and GSSG. Efficient detoxification of Sb may take place either through increases in phenolics, carotenoids, and components of the glutathione-ascorbate cycle or through the enzymatic antioxidant system. Since Dittrichia viscosa accumulates large amounts of Sb without suffering oxidative damage, it could be used for phytoremediation.

Understanding the effects of coastal defence structures on marine biota: The role of substrate composition and roughness in structuring sessile, macro- and meiofaunal communities

The increasing deployment of artificial structures into the marine environment is creating new hard substrates that differ from natural ones in physical and biological aspects. However, studies of macrofaunal and meiofaunal communities associated with artificial structures are very limited. Seawalls, cubes, acropods and rip-raps in Algeciras Bay (southern Spain) were each compared with the nearest natural hard substrate and their community structure was related to substrate roughness, composition, carbonates content, crystallinity and age, using db-RDA. The results showed clear differences between substrates for the three community levels (sessile, macro- and meiofauna). Overall, rip-raps were the most similar to natural substrates. Under similar environmental conditions, substrate roughness, composition (only for sessile) and age of the structures seemed to play important roles in structuring those communities. They especially affected the sessile community, initiating strong cascading effects that were detectable at high taxonomic level in the associated fauna.

Do artificial structures cause shifts in epifaunal communities and trophic guilds across different spatial scales?

In the current frame of proliferation of artificial structures in the sea, the ecological effects of artificial substrates on marine environments and their associate biota become a topic of great scientific and conservationist interest. This study was focused on the amphipod communities from western Mediterranean Sea and tested, using the same secondary substrate, Ellisolandia elongata, if the community and trophic structure differ between artificial (two concrete-based: cubes and tetrapods, and one natural rock-based: rip-raps) and natural substrates. Results usually showed lower taxa number and diversity in artificial substrates, as well as differences in composition and trophic structure of the amphipod community. However, patterns were not consistent for all localities, evidencing the importance of local scale. Other potential factors, besides the substrate type, should be considered to understand particularities of each locality in management and conservation strategies.

Programas de Intervención Alimentario Nutricional en America Latina y el Caribe entre 1970 y 1984

The main objective of this project was to establish an inventory of the food and nutrition programmes during the last 14 years in Latin America and the Caribbean.

Information was obtained from official documents, interviews, and meetings with programme directors.

Nearly all the countries of the region have carried out some kind of food intervention with the aim of improving the nutritional status of the vulnerable population. Of the 137 programmes identified, 126 were food supplementation programmes and 11 were subsidies.

The programmes with the highest cost per beneficiary were the on-site food consumption programmes implemented mainly through nutritional centres (US$ 3240 per beneficiary/yr); next came those in which food was distributed as part of primary health care (US$ 28.40 per beneficiary/ yr). In terms of benefit and excluding the nutritional value of food distributed, the school programmes were the least costly (US$ 8.3 per beneficiary/yr).

Funding was provided by governments with major external support, especially in Central American and Caribbean countries. Most programmes had no evaluation. Thus there is no way of determining the nutritional impact on the target population or the effectiveness of programmes. However, the coverage of most of these programmes was so limited that, even if effective, they would not represent a satisfactory solution to national food and nutrition problems

Biological Conservation of Giant Limpets: The Implications of Large Size

Patellogastropods, also known as true limpets, are distributed throughout the world and constitute key species in coastal ecosystems. Some limpet species achieve remarkable sizes, which in the most extreme cases can surpass 35cm in shell length. In this review, we focus on giant limpets, which are defined as those with a maximum shell size surpassing 10cm. According to the scientific literature, there are a total of 14 species across five genera that reach these larger sizes. Four of these species are threatened or in danger of extinction. Inhabiting the intertidal zones, limpets are frequently affected by anthropogenic impacts, namely collection by humans, pollution and habitat fragmentation. In the case of larger species, their conspicuous size has made them especially prone to human collection since prehistoric times. Size is not phylogeny-dependent among giant limpets, but is instead related to behavioural traits instead. Larger-sized species tend to be nonmigratory and territorial compared to those that are smaller. Collection by humans has been cited as the main cause behind the decline and/or extinction of giant limpet populations. Their conspicuously large size makes them the preferred target of human collection. Because they are protandric species, selectively eliminating larger specimens of a given population seriously compromises their viability and has led to local extinction events in some cases. Additionally, sustained collection over time may lead to microevolutionary responses that result in genetic changes. The growing presence of artificial structures in coastal ecosystems may cause population fragmentation and isolation, limiting the genetic flow and dispersion capacity of many limpet species. However, when they are necessitated, artificial structures could be managed to establish marine artificial microreserves and contribute to the conservation of giant limpet species that naturally settle on them.

Emergence of Klebsiella pneumoniae clinical isolates producing KPC-2 carbapenemase in Cuba

The emergence of Klebsiella pneumoniae producing carbapenemase (KPC) has now become a global concern. As a part of a nationwide multicentre surveillance study in Cuba, three K. pneumoniae clinical isolates resistant to carbapenems were detected for a 1-month period (September to October 2011). PCR and sequence analysis revealed that the three strains harboured bla KPC-2. They showed resistance or intermediate susceptibility to expanded-spectrum cephalosporins, other β-lactams, a β-lactam/β-lactamase inhibitor combination, and gentamicin. Two strains were susceptible only to colistin, whereas the other strain showing colistin resistance was susceptible to fluoroquinolones. These bla KPC -2-positive K. pneumoniae strains were classified into ST1271 (CC29), a novel clone harbouring bla KPC -2, and were revealed to be genetically identical by PCR-based DNA fingerprinting. The three patients infected with the KPC-producing K. pneumoniae had common risk factors, and had no overseas travel experience outside Cuba, suggesting local acquisition of the resistant pathogen. This is the first report of a KPC-producing K. pneumoniae in Cuba. Although detection of KPC in Enterobacteriaceae is still rare in Cuba, our finding indicated that KPC-producing bacteria are a global concern and highlighted the need to identify these microorganisms in clinical laboratories.

[Functional dyspepsia and the satiety test: its usefulness in clinical practice]

INTRODUCTION

According to the Rome III Criteria, functional dyspepsia (FD) is classified as postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). On the other hand, the satiety test (ST) has been used to evaluate gastric accommodation and emptying, distinguishing healthy individuals from those with dyspepsia.

AIMS

To determine whether the ST can distinguish dyspeptic individuals from healthy ones and to evaluate its usefulness in differentiating the two FD subtypes.

METHODS

Adults with FD were consecutively enrolled in a cross-sectional study within the time frame of August 2011 and October 2012. Healthy subjects participated as controls. The ST consisted of the intake of a nutritional supplement (Fortisip®, Nutricia Bagó®) at a constant speed; satiety was graded at 5-minute intervals (1 to 5 points). Intake was suspended when the maximum score was reported. The total ingested volume and caloric intake was recorded and the Mann-Whitney U test was used in the statistical analysis.

RESULTS

The study included 39 dyspeptic patients and 20 control individuals. The patients were predominantly women (84.6 vs. 25%; p < 0.0001) and they were similar in age (39.59 ± 13.53 vs. 34.70 ± 9.85 years) and BMI (24.32 ± 3.52 vs. 25.82 ± 3.34 kg/m2) with respect to the controls. The FD subtype percentages were PDS: 61%, EPS: 31%, and Mixed syndrome: 8%. There was a lower ingested volume and caloric intake on the part of the dyspeptic patients (185 vs. 300 ml and 277 vs. 520 Kcal, respectively. Both: P<.001). No differences in the ST were observed between the two pure dyspepsia subtypes.

CONCLUSIONS

There was a difference in the ST between healthy individuals and those with dyspepsia, but the ingested volume and caloric intake in the two FD subtypes were similar.

Pharmacokinetics of an injectable long-acting parenteral formulation of doxycycline hyclate in pigs

Based on its ideal PK/PD ratios, doxycycline hyclate (DOX-h), a time-dependant antibacterial, is ideally expected to achieve sustained plasma drug concentrations at or slightly above the MIC level for as long as possible between dosing intervals. Pursuing this end, a poloxamer-based matrix was used to produce a 10% long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its injection to pigs in the pericaudal s.c. by parallel design. Results were compared with the forced oral bolus dose and i.v. pharmacokinetics of DOX-h. For this study, 12 recently weaned pigs per group were included in this trial, and a dose of 20 mg/kg was injected in all cases. DOX-h-LA showed the greatest values for bioavailability (115.38%); maximum serum concentration (Cmax) value was 1.5 ± 0.2 with a time to reach Cmax of 3.41 ± 0.04 h and an elimination rate constant of 70.93 ± 0.87( ) h. Considering minimum effective serum concentration of 0.5 μg/mL, a dose interval of at least 5 days can be achieved for DOX-h-LA, whereas p.o. and i.v. dosing of DOX-h may only last 11 and 15 h, respectively. Pigs were slaughtered on day 30 after this trial, and no visible remnants of the preparation were detected neither fibrosis was observed after a thorough macroscopic and histopathological analysis.

Conservation status and updated census of Patella ferruginea (Gastropoda, Patellidae) in Ceuta: distribution patterns and new evidence of the effects of environmental parameters on population structure

The Strait of Gibraltar has important populations of the highly endangered patellid limpet Patella ferruginea. Between 2006 and 2010, an exhaustive census was carried out in Ceuta. The total coastline was divided into 17 sectors. The coast of each sector was examined by using 10 m transects. For the case of those sectors composed of breakwaters, jetties or islets, no transects were used, and instead, the total number of individuals was recorded. Each individual was measured to the nearest millimetre using a calliper. Moreover, the complete rocky shore length where the species could potentially be present was calculated, and an estimation of the total number of individuals that each sector could host was made. Results indicate that Ceuta could be home to around 44,000 individuals. The species found in Point Benzú, its westernmost limit of distribution on the North African coasts. The largest populations were recorded on the South Bay, with higher Mediterranean influence. Our results indicate that substrate roughness (topographic heterogeneity) and the area’s accessibility highly influence the abundance and population structure. Those populations located on high topographic heterogeneity substrates show higher recruitment rates and lower percentages of larger individuals, while medium to low rugosity surfaces presented the opposite pattern. Additionally, easily accessible areas (and frequented by humans) presented smaller average shell sizes. Implications of the results for conservation purposes are discussed.

Present status of the endangered limpet Cymbula nigra (Gastropoda, Patellidae) in Ceuta: how do substrate heterogeneity and area accessibility affect population structure?

Cymbula nigra (Gastropoda, Patellidae) is a threatened giant patellid limpet found on the North African coast from Namibia to Algeria. The objective of this study was to estimate the total number of individuals present in Ceuta (Strait of Gibraltar) and to determine the effect of certain physical parameters on population structure and abundance. Between 2006 and 2010 we conducted an exhaustive census in the area. Results indicate that Ceuta could be home to 48,473 individuals. The most important populations were recorded on the North Bay, characterized by its Atlantic influence. While for other similar species, such as Patella ferruginea, human accessibility to the area plays an important role in determining the structure of populations, we found that substrate roughness (small scale topographic heterogeneity) is the main determining factor in this species. Populations located on medium to low topographic heterogeneity substrates showed higher percentages of medium and large size individuals. However, recruitment rates did not differ between substrata of different roughness. Finally, and through the analysis of the C. nigra populations located on some recently constructed jetties, we obtained interesting new data regarding individual growth rates, thus contributing to our knowledge of the population structure of the species.

Populational status of the endangered mollusc Patella ferruginea Gmelin, 1791 (Gastropoda, Patellidae) on Algerian islands (SW Mediterranean)

Patella ferruginea is the most endangered endemic marine inverte­brate on the Western Mediterranean coasts according to the European Council Directive 92/43/EEC. A total of 1,017 individuals were recorded in the present study along western Algerian islands, with mean densities ranging from 0.8 to 35.3 ind/m per linear transect and averages of 4.8 ind/m per linear transect for Western Habibas Island and 22 ind/m for Plane Island, making these islands a hot spot for the species in the Medi­terranean. The expected total number of specimens in Habibas would therefore be 50,400. The mean size of P. ferruginea on the Habibas Islands (4.45 cm) was significantly (p < 0.001) greater than on Plane Island (2.78 cm). Recruitment was high in Plane Island and the northern sector of the western Habibas Islands. Lar­ge adults had very conical shells. The fact that Habibas Islands is now a marine reserve could explain these differences in populations. Conservation of these populations should be a priority in order to avoid extinction of the species.

Increased motor drive and sleep loss in mice lacking Kv3-type potassium channels

The voltage-gated potassium channels Kv3.1 and Kv3.3 are widely expressed in the brain, including areas implicated in the control of motor activity and in areas thought to regulate arousal states. Although Kv3.1 and Kv3.3-single mutants show some physiological changes, previous studies revealed relatively subtle behavioral alterations suggesting that Kv3.1 and Kv3.3 channel subunits may be encoded by a pair of redundant genes. In agreement with this hypothesis, Kv3.1/Kv3.3-deficient mice display a 'strong' mutant phenotype that includes motor dysfunction (ataxia, myoclonus, tremor) and hyperactivity when exposed to a novel environment. In this paper we report that Kv3.1/Kv3.3-deficient mice are also constitutively hyperactive. Compared to wildtype mice, double mutants display 'restlessness' that is particularly prominent during the light period, when mice are normally at rest, characterized by more than a doubling of ambulatory and stereotypic activity, and accompanied by a 40% sleep reduction. When we reinvestigated both single mutants, we observed constitutive increases of ambulatory and stereotypic activity in conjunction with sleep loss in Kv3.1-single mutants but not in Kv3.3-single mutants. These findings indicate that the absence of Kv3.1-channel subunits is primarily responsible for the increased motor drive and the reduction in sleep time.

Redox-related peroxidative responses evoked by methyl-jasmonate in axenically cultured aeroponic sunflower (Helianthus annuus L.) seedling roots

Methyl-jasmonate (MeJA) has been proposed to be involved in the evocation of defense reactions, as the oxidative burst in plants, substituting the elicitors or enhancing their effect. 48 h dark- and sterilely cultured (axenic) aeroponic sunflower seedling roots excised and treated with different concentrations of MeJA showed a strong and quick depression of the H(+) efflux rate, 1.80 microM MeJA totally stopping it for approximately 90 min and then reinitiating it again at a lower rate than controls. These results were wholly similar to those obtained with nonsterilely cultured roots and have been interpreted as mainly based on H(+) consumption for O(2)(*-) dismutation to H(2)O(2). Also K(+) influx was strongly depressed by MeJA, even transitorily reverting to K(+) efflux. These results were consistent with those associated to the oxidative burst in plants. MeJA induced massive H(2)O(2) accumulation in the middle lamella and intercellular spaces of both the root cap cells and the inside tissues of the roots. The native acidic extracellular peroxidase activity of the intact (nonexcised) seedling roots showed a sudden enhancement (by about 52%) after 5 min of MeJA addition, maintained for approximately 15 min and then decaying again to control rates. O(2) uptake by roots gave similar results. These and other results for additions of H(2)O(2) or horseradish peroxidase, diphenylene iodonium, and sodium diethyldithiocarbamate trihydrate to the reaction mixture with roots were all consistent with the hypothesis that MeJA induced an oxidative burst, with the generation of H(2)O(2) being necessary for peroxidase activity. Results with peroxidase activity of the apoplastic fluid were in accordance with those of the whole root. Finally, MeJA enhanced NADH oxidation and inhibited hexacyanoferrate(III) reduction by axenic roots, and diphenylene iodonium cancelled out these effects. Redox activities by CN(-)- preincubated roots were also studied. All these results are consistent with the hypothesis that MeJA enhanced the NAD(P)H oxidase of a redox chain linked to the oxidative burst, so enhancing the generation of O(2)(*-) and H(2)O(2), O(2) uptake, and peroxidase activity by roots.

Alcohol hypersensitivity, increased locomotion, and spontaneous myoclonus in mice lacking the potassium channels Kv3.1 and Kv3.3

The Shaw-like potassium (K(+)) channels Kv3.1 and Kv3.3 are widely coexpressed in distinct neuronal populations in the CNS, possibly explaining the relatively "mild" phenotypes of the Kv3.1 and the Kv3.3 single mutant. Kv3.1-deficient mice show increased cortical gamma- and decreased delta-oscillations (Joho et al., 1997, 1999); otherwise, the Kv3.1-mutant phenotype is relatively subtle (Ho et al., 1997; Sánchez et al., 2000). Kv3.3-deficient mice display no overt phenotype (Chan, 1997). To investigate whether Kv3.1 and Kv3.3 K(+) channels are functionally redundant, we generated the Kv3.1/Kv3.3 double mutant. Kv3.1/Kv3.3-deficient mice were born at the expected Mendelian frequencies indicating that neither Kv3.1 nor Kv3.3 K(+) channels are essential for embryonic development. Although there are no obvious changes in gross brain anatomy, adult Kv3.1/Kv3.3-deficient mice display severe ataxia, tremulous movements, myoclonus, and hypersensitivity to ethanol. Mice appear unbalanced when moving, whereas at rest they exhibit whole-body jerks every few seconds. In spite of the severe motor impairment, Kv3.1/Kv3.3-deficient mice are hyperactive, show increased exploratory activity, and display no obvious learning or memory deficit. Myoclonus, tremor, and ethanol hypersensitivity are only seen in the double-homozygous Kv3.1/Kv3.3-deficient mice, whereas increased locomotor and exploratory activity are also present in double-heterozygous mice. The graded penetrance of mutant traits appears to depend on the number of null alleles, suggesting that some of the distinct phenotypic traits visible in the absence of Kv3.1 and Kv3.3 K(+) channels are unrelated and may be caused by localized dysfunction in different brain regions.

Local structure probes of nanoscale heterogeneity in crystalline materials

In the conventional model of condensed matter increasing numbers of defects break down the order and ultimately convert perfect periodic crystals into aperiodic glasses. Local structure probes of a variety of materials with non-stoichiometric compositions, multiple degenerate ordering modes, or other symmetry breaking factors identify multiple ordered arrangements of atoms that render the materials heterogeneous on the nanometer scale. While exerting apparently negligible effects on bulk properties, this heterogeneity or phase separation does influence correlated or collective properties such as magnetism and phase stability.

Effect of dichlorophenolindophenol, dichlorophenolindophenol-sulfonate, and cytochrome c on redox capacity and simultaneous net H+/K+ fluxes in aeroponically grown seedling roots of sunflower (Helianthus annuus L.): new evidence for a plasma membrane CN(-)-resistant redox chain

Excised roots from axenically grown sunflower seedlings reduced or oxidized exogenously added 2,6-dichlorophenolindophenol (DCIP), DCIP-sulfonate (DCIP-S), and cytochrome c, and affected simultaneous H+/K+ net fluxes. Experiments were performed with nonpretreated "living" and CN(-)-pretreated "poisoned" roots (control and CN(-)-roots). CN(-)-roots showed no H+/K+ net flux activity but still affected the redox state of the compounds tested. The hydrophobic electron acceptor DCIP decreased the rate of H+ efflux in control roots with extension of the maximum rate and optimal pH ranges, then the total net H+ efflux ([symbol: see text]H+) equalled that of the roots without DCIP. The simultaneously measured K+ influx rate was first inhibited, then inverted into efflux, and finally influx recovered to low rates. This effect could not be due to uptake of the negatively charged DCIP, but due to the lower H+ efflux and the transmembrane electron efflux caused by DCIP, which would depolarize the membrane and open outward K+ channels. The different H+ efflux kinetics characteristics, together with the small but significant DCIP reduction by CN(-)-roots were taken as evidence that an alternative CN(-)-resistant redox chain in the plasma membrane was involved in DCIP reduction. The hydrophilic electron acceptor DCIP-S enhanced both H+ and K+ flux rates by control roots. DCIP-S was not reduced, but slightly oxidized by control roots, after a lag, while CN(-)-roots did not significantly oxidize or reduce DCIP-S. Perhaps the hydrophobic DCIP could have access to and drain electrons from an intermediate carrier deep inside the membrane, to which the hydrophilic DCIP-S could not penetrate. Also cytochrome c enhanced [symbol: see text]H+ and [symbol: see text]K+, consistent with the involvement of the CN(-)-resistant redox chain. Control roots did not reduce but oxidize cytochrome c after a 15 min lag, and CN(-)-roots doubled the rate of cytochrome c oxidation without any lag. NADH in the medium spontaneously reduced cytochrome c, but control or CN(-)-roots oxidized cytochrome c, despite of the presence of NADH. In this case CN(-)-roots were less efficient, while control roots doubled the rate of cytochrome c oxidation by CN(-)-roots, after a 10 min lag in which cytochrome c was reduced at the same rate as the medium plus NADH did. CN(-)-roots seemed to have a fully activated CN(-)-resistant branch. The described effects on K+ flux were consistent with the current hypothesis that redox compounds changed the electric membrane potential (de- or hyperpolarization), which induces the opening of voltage-gated in- or outward K+ channels.

Dual regulation of the T-type Ca(2+) current by serum albumin and beta-estradiol in mammalian spermatogenic cells

This study provides evidence for a novel mechanism of voltage-gated Ca(2+) channel regulation in mammalian spermatogenic cells by two agents that affect sperm capacitation and the acrosome reaction (AR). Patch-clamp experiments demonstrated that serum albumin induced an increase in Ca(2+) T current density in a concentration-dependent manner, and significant shifts in the voltage dependence of both steady-state activation and inactivation of the channels. These actions were not related to the ability of albumin to remove cholesterol from the membrane. In contrast, beta-estradiol significantly inhibited Ca(2+) channel activity in a concentration-dependent and essentially voltage-independent fashion. In mature sperm this dual regulation may influence capacitation and/or the AR.

Anion channel blockers differentially affect T-type Ca(2+) currents of mouse spermatogenic cells, alpha1E currents expressed in Xenopus oocytes and the sperm acrosome reaction

The direct electrophysiological characterization of sperm Ca(2+) channels has been precluded by their small size and flat shape. An alternative to study these channels is to use spermatogenic cells, the progenitors of sperm, which are larger and easier to patch-clamp. In mouse and rat, the only voltage-dependent Ca(2+) currents displayed by these cells are of the T type. Because compounds that block these currents inhibit the zona pellucida-induced Ca(2+) uptake and the sperm acrosome reaction (AR) at similar concentrations, it is likely that they are fundamental for this process. Recent single channel recordings in mouse sperm demonstrated the presence of a Cl(-) channel. This channel and the zona pellucida (ZP)-induced AR were inhibited by niflumic acid (NA), an anion channel blocker [Espinosa et al. (1998): FEBS Lett 426:47-51]. Because NA and other anion channel blockers modulate cationic channels as well, it became important to determine whether they affect the T-type Ca(2+) currents of spermatogenic cells. These currents were blocked in a voltage-dependent manner by NA, 1, 9-dideoxyforskolin (DDF), and 5-nitro-2-(3-phenylpropylamine)benzoic acid (NPPB). The IC(50) values at -20 mV were 43 microM for NA, 28 microM for DDF, and 15 microM for NPPB. Moreover, DDF partially inhibited the ZP-induced AR (40% at 1 microM) and NPPB displayed an IC(50) value of 6 microM for this reaction. These results suggest that NA and DDF do not inhibit the ZP-induced AR by blocking T-type Ca(2+) currents, while NPPB may do so. Interestingly 200 microM NA was basically unable to inhibit alpha1E Ca(2+) channels expressed in Xenopus oocytes, questioning that this alpha subunit codes for the T-type Ca(2+) channels present in spermatogenic cells. Evidence for the presence of alpha1C, alpha1G, and alpha1H in mouse pachytene spematocytes and in round and condensing spermatids is presented.

Quantitative assessment of cerebral hemodynamics using CT: stability, accuracy, and precision studies in dogs

PURPOSE

The limited clinical availability of currently used methods to measure regional cerebral blood volume (CBV) and cerebral blood flow (CBF) represents an important restriction. We undertook this study to evaluate a new dynamic CT method to measure CBV and CBF in normal and ischemic tissue.

METHOD

A total of 21 dynamic CT studies were performed in seven male beagles. The contrast enhancement curves of the carotid arteries and of various brain regions were deconvolved to obtain CBV and CBF. The stability of the deconvolution method employed was assessed by comparing three data sets obtained by analyses of one, two, and four regions of interest (ROIs), all covering the entire brain area. The accuracy of CT-derived CBF was analyzed for normal (n = 5 studies) and ischemic (n = 7 studies) brain tissue using fluorescent microspheres. Repetitive CT studies were performed to evaluate the precision of the CT measurements.

RESULTS

The stability of the deconvolution method was high with variabilities of 2.3% (CBV), 5.9% (CBF), and 8.9% (mean transit time), respectively. The correlation between the CT and the microsphere measurements was good for both normal and ischemia studies (r > 0.78, slope > 0.9). The variability of the CT CBF (30.6%) was higher than that of the CT CBV (12.3%) measurements.

CONCLUSION

Our novel dynamic CT method is stable with respect to the sizes of ROIs used, allowing for accurate measurements of CBV and CBF in both normal and ischemic tissue. Further studies are necessary to evaluate the variability of this method under controlled physiologic conditions.

Ion channels in sperm physiology

Fertilization is a matter of life or death. In animals of sexual reproduction, the appropriate communication between mature and competent male and female gametes determines the generation of a new individual. Ion channels are key elements in the dialogue between sperm, its environment, and the egg. Components from the outer layer of the egg induce ion permeability changes in sperm that regulate sperm motility, chemotaxis, and the acrosome reaction. Sperm are tiny differentiated terminal cells unable to synthesize protein and difficult to study electrophysiologically. Thus understanding how sperm ion channels participate in fertilization requires combining planar bilayer techniques, in vivo measurements of membrane potential, intracellular Ca2+ and intracellular pH using fluorescent probes, patch-clamp recordings, and molecular cloning and heterologous expression. Spermatogenic cells are larger than sperm and synthesize the ion channels that will end up in mature sperm. Correlating the presence and cellular distribution of various ion channels with their functional status at different stages of spermatogenesis is contributing to understand their participation in differentiation and in sperm physiology. The multi-faceted approach being used to unravel sperm ion channel function and regulation is yielding valuable information about the finely orchestrated events that lead to sperm activation, induction of the acrosome reaction, and in the end to the miracle of life.

Mouse sperm patch-clamp recordings reveal single Cl- channels sensitive to niflumic acid, a blocker of the sperm acrosome reaction

Ion channels lie at the heart of gamete signaling. Understanding their regulation will improve our knowledge of sperm physiology, and may lead to novel contraceptive strategies. Sperm are tiny (approximately 3 microm diameter) and, until now, direct evidence of ion channel activity in these cells was lacking. Using patch-clamp recording we document here, for the first time, the presence of cationic and anionic channels in mouse sperm. Anion selective channels were blocked by niflumic acid (NA) (IC50 = 11 microM). The blocker was effective also in inhibiting the acrosome reaction induced by the zona pellucida, GABA or progesterone. These observations suggest that Cl- channels participate in the sperm acrosome reaction in mammals.

High-resolution sonography of the abnormal cranial suture

OBJECTIVE

The purpose of this investigation is to elucidate the sonographic features of abnormal major cranial sutures.

MATERIALS AND METHODS

Eight excised synostosed suture specimens were evaluated. The high-resolution sonographic appearance was correlated with the histological section, plain radiographs, CT and MRI. Diastatic and molded sutures were also evaluated with sonography and compared with the normal cranial suture appearance.

RESULTS

Synostosed sutures demonstrated one or more of the following features: (a) loss of echo-poor fibrous gap between bony plates (five sagittal and coronal synostoses); (b) irregular thickened inner sutural margin (three lambdoid synostoses); (c) loss of bevelled edge (one lambdoid synostosis); (d) asymmetric anterior fontanelle (one coronal synostosis). Cranial molding results in an overlap of echogenic bony plates. Sutural width (the distance between bony plates) is increased in cases of elevated intracranial pressure.

CONCLUSION

Sonography is an inexpensive, radiation-free modality which can confirm synostosis versus molding versus an underlying intracranial lesion as a cause of plagiocephaly. The high-resolution sonographic images also provide a relatively easy means to assess sutural width and may provide information in regard to increased intracranial pressure.

Mouse sperm membrane potential: changes induced by Ca2+

Mouse sperm resting membrane potential (Er) (-42 +/- 8.8 mV), determined with a potential sensitive dye, depended on extracellular K+ and, in the absence of extracellular Ca2+ ([Ca2+]e), on external Na+ ([Na+]e). Ca2+ addition (> 5 microM) to sperm in Ca-free media induced a transient hyperpolarization (Ca-ith) which strongly depended on [Na+]e and less on external Cl- ([Cl-]e). Cd2+ and Mn2+ (microM) mimicked the Ca2+ effect, but not Ba2+. The Ca-ith was partially inhibited by ouabain (74%, IC50 = 5.8 microM) and niflumic acid (38%, IC50 = 240 microM), indicating the participation of the Na-K ATPase and Cl- channels. In Ca-free low-Na+ media, Ca2+ addition caused a depolarization sensitive to: nimodipine (25 microM), trifluoperazine (12.5 microM) and Mg2+ (1.2 mM), suggesting the participation of Ca2+ channels. Since some inhibitors of the sperm Ca-ith block the acrosome reaction (AR), both processes may share transport systems.

[Leukocyte migration inhibitory factor and basophil degranulation in drug reactions]

We performed a prospective study in patients with a medical history of adverse reaction to drugs with the purpose of rule out allergy. We included 31 patients who were attended in the Allergy Service. We compared the sensibility and specificity of the test of inhibition factor of leucocytes migration and degranulation basophil against the exposition. After the statistical analysis, we concluded: the laboratory test, we have already mentioned, have little sensibility and specificity so the exposition test in the quickest, useful, and more simple method to determine drugs allergy, but more dangerous.

Arterial wall changes in cerebral vasospasm

A right-sided subarachnoid hemorrhage (SAH) was created in 12 monkeys. Only the right (clot-side) cerebral arteries developed angiographic vasospasm (VSP), which was maximal 7 days after SAH. Eight animals were killed at this time and the remainder at 14 days. At the time of killing the middle cerebral arteries (MCAs) were harvested, and four normal, left (non-clot-side) MCAs were vasoconstricted in vitro with prostaglandin F2 alpha. All MCAs were studied with scanning and transmission electron microscopy. Right MCAs in maximal VSP 7 days from SAH were undistinguishable on scanning electron microscopy from normal arteries vasoconstricted in vitro: both groups demonstrated a mean 57% reduction in vessel caliber and a 5-fold increase in vessel wall thickness compared to normal, nonvasoconstricted left MCAs. On transmission electron microscopy, however, arteries in SAH-induced VSP showed degenerative changes in the tunica intima and media. These changes were still evident at 14 days, despite considerable resolution of VSP. These findings, as well as those from other pathological studies of animal and human cerebral arteries in VSP, suggest that the arterial narrowing and vessel wall thickening seen within several weeks of SAH is due primarily to medial contraction, but unlike simple vasoconstriction, is associated with degenerative ultrastructural changes in the endothelium and vascular smooth muscle cells which may denote a temporarily irreversible state.

Arterial Wall Changes in Cerebral Vasospasm

A right-sided subarachnoid hemorrhage (SAH) was created in 12 monkeys. Only the right (clot-side) cerebral arteries developed angiographic vasospasm (VSP), which was maximal 7 days after SAH. Eight animals were killed at this time and the remainder at 14 days. At the time of killing the middle cerebral arteries (MCAs) were harvested, and four normal, left (non-clot-side) MCAs were vasoconstricted in vitro with prostaglandin F2… All MCAs were studied with scanning and transmission electron microscopy. Right MCAs in maximal VSP 7 days from SAH were undistinguishable on scanning electron microscopy from normal arteries vasoconstricted in vitro: both groups demonstrated a mean 57% reduction in vessel caliber and a 5-fold increase in vessel wall thickness compared to normal, nonvasoconstricted left MCAs. On transmission electron microscopy, however, arteries in SAH-induced VSP showed degenerative changes in the tunica intima and media. These changes were still evident at 14 days. despite considerable resolution of VSP. These findings, as well as those from other pathological studies of animal and human cerebral arteries in VSP, suggest that the arterial narrowing and vessel wall thickening seen within several weeks of SAH is due primarily to medial contraction, but unlike simple vasoconstruction, is associated with degenerative ultrastructural changes in the endothelium and vascular smooth muscle cells which may denote a temporarily irreversible state.

Electron microscopy of simian cerebral arteries after subarachnoid hemorrhage and after the injection of horseradish peroxidase

A large unilateral subarachnoid hemorrhage (SAH) was created in 21 monkeys, and horseradish peroxidase (HRP) was injected into the cisterna magna or left internal carotid artery in 3 others (normals). Cerebral fixation was performed on Day 14 after SAH or 15 minutes after HRP injection. The major cerebral arteries from both the nonclot (control) and clot sides and the normal animals were examined with scanning and transmission electron microscopy (SEM and TEM). SEM of the adventitial surfaces of control and normal arteries revealed tunnel-like structures along the longitudinal axis. No vasa vasorum were seen, but adventitial rounded openings were observed, 10 to 35 micron in diameter in vessels of the anterior circulation and up to 80 micron in diameter in the basilar arteries. The stomas, numbering 5 to 10/mm of specimen, appeared to connect the subarachnoid and intraadventitial spaces or pathways. In SAH arteries, the tunica adventitia was coated with cellular remnants of hematoma or dense, well-organized blood clots, the removal of which revealed blocked stomas. TEM showed HRP in the vessel walls after injection into the cisterna magna, but not after injection into the carotid artery. TEM of control arteries revealed Virchow-Robin (intraadventitial) spaces lined by simple planar epithelium-like cells; Virchow-Robin spaces contained sparse nerve fiber bundles and connective tissue fibers. In SAH arteries, these spaces were almost filled with strands of connective tissue and fibroblasts; no nerve fibers were detected. Vasogenic substances probably reach smooth muscle cells via the adventitial stomas. SAH occluding the stomas may block the cerebrospinal fluid circulation, disturbing nutrition of the arterial wall or removal of wastes from it, thereby aggravating vasospasm.

A randomized placebo-controlled double-blind trial of nimodipine after SAH in monkeys. Part 2: Pathological findings

Chronic cerebral vasospasm was induced in monkeys by placement of an autologous blood clot after the basal cisterns had been opened over the arteries of the circle of Willis on one side. The experimental protocol was detailed in Part 1 of this paper. Twenty of the 30 monkeys studied from both groups (one receiving placebo and the other nimodipine) underwent cerebral fixation (Day 14) at controlled pressure by intra-arterial perfusion. The arteries at the base of the brain were studied by light microscopy and scanning (SEM) and transmission electron microscopy (TEM). Cerebral angiography on Day 7 showed that vasospasm was significantly more common (p less than 0.0001) and more severe (p less than 0.01) on the clot side compared to the control or non-clot side. Vasospasm was less severe on Day 14, just before sacrifice. On SEM, 80% of the 20 middle cerebral artery (MCA) specimens that had been in spasm (Day 7) showed marked corrugation , and in some the endothelium had a fish-scale appearance. All of the 10 MCA's on the clot side examined by TEM that had been in spasm (Day 7) showed marked changes such as endothelial swelling, subendothelial proliferation, corrugation of the elastic lamina, and myonecrosis. With few exceptions, none of the basilar arteries or MCA's on the non-clot (control) side showed any abnormalities. The pathological findings of vessels in spasm were considered to be slightly less severe in the nimodipine group; however, the trial drug (1 mg/kg/8 hrs) did not prevent such abnormalities from occurring. The ultrastructural changes in the arterial walls of specimens from both placebo and nimodipine groups in vasospasm are described. Since dramatic changes are present in the vessel walls even after radiologically visible vasospasm has almost completely abated, we believe that vasospasm is due to long-lasting smooth-muscle constriction and not to vessel wall thickening caused by a cellular or subcellular infiltrate.

A randomized placebo-controlled double-blind trial of nimodipine after SAH in monkeys. Part 1: Clinical and radiological findings

The authors have developed a method to induce chronic cerebral vasospasm after subarachnoid hemorrhage (SAH) in monkeys. With microsurgical techniques, 33 monkeys had a frontotemporal craniectomy and unilateral opening of the subarachnoid cisterns. Cerebrospinal fluid was drained and a fresh hematoma, obtained from an average of 7 ml of autologous blood, was carefully placed against the major arteries of the anterior circulation on one side. The 30 monkeys studied for 7 to 14 days after the SAH were allocated randomly to two treatment groups of 15: one group received placebo and the other nimodipine, 1 mg/kg every 8 hours. Indices monitored before and after SAH included neurological status, cerebral blood flow, computerized tomography, and angiographic vessel caliber. In the placebo group, delayed ischemic neurological deficit developed in one monkey 4 days after clot placement and was present at sacrifice on Day 14. No such deficit occurred in the nimodipine group. The effect of nimodipine on vessel caliber at this dosage was equivocal. Significant vasospasm (31% to 100% reduction in vessel caliber) developed in 87% (26 of 30) of the animals. Overall, vasospasm was slightly more common in the placebo group: in this group, on Days 7 and 14, the incidence of vasospasm was significantly higher (p less than 0.05) than in the nimodipine group. However, the average percentage reduction in vessel caliber of the maximally constricted vessel in each monkey was not significantly different between the two groups.

Rupture of an experimentally induced aneurysm in a primate

Cerebral aneurysms are extremely rare in all animals except man. We report the occurrence of a carotid-ophthalmic aneurysm in a cynomolgous monkey two months following accidental occlusion of the ipsilateral cervical internal carotid artery. This was documented angiographically. The aneurysm was deliberately ruptured by the insertion and withdrawal of fine needles. This produced a large subarachnoid hemorrhage visualized on CT scan. There was a progressive severe fall in cerebral blood flow and moderate vasospasm. The neurological status deteriorated on the tenth day and the animal was sacrificed on day 13. On electron microscopy, the aneurysm showed a fibrous wall, and the endothelium showed balloon-like endothelial cells with gaps. Corrugations occurred in the inner aspect of the anterior circulation arteries.