Ambient air pollution, covert cerebrovascular disease and cognition: results from the ISSYS study.

BACKGROUND AND PURPOSE: Although air pollution (AP) has been associated with stroke and dementia, data regarding its relationship with covert cerebrovascular disease (cCVD) and cognition over time are sparse. The aim of this study was to explore these relationships. METHODS: A prospective population-based study of 976 stroke-free and non-demented individuals living in Barcelona, Spain, was conducted during 2010-2016. A land use regression model was used to estimate the exposure of each participant to AP: NOx, NO2, PM2.5, PM10, PMcoarse and PM2.5 absorbance. Cognitive function and cCVD were assessed at baseline (n = 976) and 4 years after (n = 317). Multivariate-adjusted models were developed. RESULTS: At baseline, 99 participants (10.1%) had covert brain infarcts and 91 (9.3%) had extensive periventricular white matter hyperintensities (WMHs). Marked subcortical WMH progression was seen in 19.7%; the incidence of other covert cerebrovascular lessons ranged between 5% and 6% each. PM2.5 was related to higher odds of having a covert brain infarct (odds ratio [OR] 2.21; 95% confidence interval [CI] 1.06-4.60). PM2.5 absorbance was related to higher odds of having extensive subcortical WMHs (OR 1.72; 95% CI 1.13-2.60), whereas NO2 was related to higher odds of having extensive subcortical (OR 1.66; 95% CI 1.17-2.35) or periventricular (OR 1.96; 95% CI 1.10-3.50) WMHs and to higher odds of developing marked subcortical WMH progression (OR 1.40; 95% CI 1.05-1.90). NOx was related to incident cerebral microbleeds (OR 1.36; 95% CI 1.04-1.79). There was no association between AP and cognition. CONCLUSIONS: Air pollutant predicts the presence and accumulation of cCVD. Its impact on cognitive impairment remains to be determined.

Effect of the cap layer growth temperature on the Sb distribution in InAs/InSb/InAs sub-monolayer heterostructures for mid-infrared devices.

Sub-monolayer (SML) deposition of InSb within InAs matrix by migration enhanced epitaxy tends to form type II SML nanostructures offering efficient light emission within the mid-infrared (MIR) range between 3 and 5 µm. In this work, we report on the Sb distribution in InSb/InAs SML nanostructures with InAs cap layers grown at temperatures lower than that associated with the under-grown InSb active layer. Analysis by transmission electron microscopy (TEM) in 002 dark field conditions shows that the reduction in the growth temperature of the InAs cap layer increases the amount of Sb deposited in the layers, in good agreement with the x-ray diffraction results. TEM micrographs also show that the layers are formed by random InSbAs agglomerates, where the lower cap temperature leads to a more continuous InSb layer. Quantitative atomic column resolved high angle annular dark field-scanning (S)TEM analyses also reveal atomic columns with larger composition of Sb for the structure with the lowest InAs cap layer temperature. The dependence of the Sb distribution on InAs cap growth temperature allows tuning the corresponding emission wavelength in the MIR range, as shown by the photoluminescence emission spectra.

Investigation on Sb distribution for InSb/InAs sub-monolayer heterostructure using TEM techniques.

InSb/InAs sub-monolayer (SML) nanostructures such as SML quantum dots offer sharper emission spectra, a better modal gain and a larger modulation bandwidth compared to its Stranski-Krastanov counterpart. In this work, the Sb distribution of SML InSb layers grown by migration enhanced epitaxy has been analyzed by transmission electron microscopy (TEM) techniques. The analysis of the material by diffraction contrast in 002 dark field conditions and by atomic column resolved high angle annular dark field-scanning TEM reveal the presence of a low Sb content InSbAs continuous layer with scarce Sb-rich InSbAs agglomerates. The intensity profiles obtained by both techniques point to Sb segregation during growth. This segregation has been quantified using the Muraki segregation model obtaining a high segregation coefficient R of 0.81 towards the growth direction. The formation of a continuous InSbAs wetting layer as a result of a SML deposition of Sb on the InAs surface is discussed.

[Inflammatory bowel disease during pregnancy]. / Embarazo en enfermedad inflamatoria intestinal: no solo 9 meses de cuidado.

The prevalence of inflammatory bowel disease (IBD) increased in the last decades. Thus, the number of pregnant women with the condition is also increasing. Given that active disease itself is the main risk factor for complications during pregnancy, it is necessary to achieve a complete remission before planning a pregnancy. Also, pregnant women with IBD must be monitored noninvasively and be treated proactively, including escalated therapies, if needed, to prevent potential flares during pregnancy. Patients can undergo vaginal delivery in most forms of IBD. However, cesarean delivery is still preferable in women with a history of ileal pouch-anal anastomoses (IPAA) or active perianal disease.

Do people care about pine invasions? Visitor perceptions and willingness to pay for pine control in a protected area.

Tree invasions are increasing globally, causing major problems for biodiversity, ecosystem services and human well-being. In South America, conifer invasions occur across many ecosystems and while numerous studies address the ecological consequences of these invasions, little is known about social perceptions and people's attitudes toward their control. The social perceptions on the effect of invasive conifers can include recreational, cultural and conservation dimensions. This study, conducted in the Malalcahuello National Reserve, aims to assess visitor's perception about invasive pines (Pinus spp.) and their effects on the endangered Araucaria araucana forests and determine their willingness to pay for pine control. We used a questionnaire to survey visitors to the reserve in both winter and summer (n = 138 for each season). When confronted with six images of araucaria and pine forests with and without snow, visitors consistently preferred landscapes without pines and disliked those completely dominated by pines the most. Almost half, 46.5%, of the visitors expressed their willingness to pay (WTP) for pine control and after given a brief explanation about pine impacts, this number rose to 79%. Visitors who said they were unwilling to pay argue ethical, aesthetic and pragmatic considerations relating closely to a number of social value systems and beliefs. Our study shows that there is a high variation in how people assess the threat of invasive pine species in natural areas, but education even in a very brief format can help to increase awareness of the problem and build social and financial support for its control.

Clarifying values, risk perceptions, and attitudes to resolve or avoid social conflicts in invasive species management.

Decision makers and researchers recognize the need to effectively confront the social dimensions and conflicts inherent to invasive species research and management. Yet, despite numerous contentious situations that have arisen, no systematic evaluation of the literature has examined the commonalities in the patterns and types of these emergent social issues. Using social and ecological keywords, we reviewed trends in the social dimensions of invasive species research and management and the sources and potential solutions to problems and conflicts that arise around invasive species. We integrated components of cognitive hierarchy theory and risk perceptions theory to provide a conceptual framework to identify, distinguish, and provide understanding of the driving factors underlying disputes associated with invasive species. In the ISI Web of Science database, we found 15,915 peer-reviewed publications on biological invasions, 124 of which included social dimensions of this phenomenon. Of these 124, 28 studies described specific contentious situations. Social approaches to biological invasions have emerged largely in the last decade and have focused on both environmental social sciences and resource management. Despite being distributed in a range of journals, these 124 articles were concentrated mostly in ecology and conservation-oriented outlets. We found that conflicts surrounding invasive species arose based largely on differences in value systems and to a lesser extent stakeholder and decision maker's risk perceptions. To confront or avoid such situations, we suggest integrating the plurality of environmental values into invasive species research and management via structured decision making techniques, which enhance effective risk communication that promotes trust and confidence between stakeholders and decision makers.

Influence of land use and climate on the load of suspended solids in catchments of Andean rivers.

Understanding the interaction between anthropogenic land use and the rainfall pattern can be crucial to predict changes in total suspended solids (TSS) in streams and rivers. We assessed the effects of land use and annual rainfall on the TSS load of 19 southern Chilean catchments. The results indicated that the concentration of TSS increased in catchments with a rainy regime and greater annual precipitation. TSS load also increased as the surface of open areas increased at the catchment scale and decreased with increasing cover of glaciers and perennial snow. However, we did not find support for models with interaction terms between climate and land use. Results suggest that a regional decrease in annual rainfall accompanied by an increase in the altitude of the zero isotherms, as predicted by climate models, should have multiple effects on TSS. In particular, increased TSS load can be expected from a contraction of glaciers and perennial snow areas as well as the intensification of new crops and urban expansion.

Household model of Chagas disease vectors (Hemiptera: Reduviidae) considering domestic, peridomestic, and sylvatic vector populations.

ABSTRACT Disease transmission is difficult to model because most vectors and hosts have different generation times. Chagas disease is such a situation, where insect vectors have 1-2 generations annually and mammalian hosts, including humans, can live for decades. The hemataphagous triatominae vectors (Hemiptera: Reduviidae) of the causative parasite Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) usually feed on sleeping hosts, making vector infestation of houses, peridomestic areas, and wild animal burrows a central factor in transmission. Because of difficulties with different generation times, we developed a model considering the dwelling as the unit of infection, changing the dynamics from an indirect to a direct transmission model. In some regions, vectors only infest houses; in others, they infest corrals; and in some regions, they also infest wild animal burrows. We examined the effect of sylvatic and peridomestic vector populations on household infestation rates. Both sylvatic and peridomestic vectors increase house infestation rates, sylvatic much more than peridomestic, as measured by the reproductive number R0. The efficacy of manipulating parameters in the model to control vector populations was examined. When R0 > 1, the number of infested houses increases. The presence of sylvatic vectors increases R0 by at least an order of magnitude. When there are no sylvatic vectors, spraying rate is the most influential parameter. Spraying rate is relatively unimportant when there are sylvatic vectors; in this case, community size, especially the ratio of houses to sylvatic burrows, is most important. The application of this modeling approach to other parasites and enhancements of the model are discussed.

Association between serum calcium levels and the presentation of postpartum endometritis in housed dairy cows.

The present work aims to identify the minimum threshold of serum calcium (SC) values in cows during the first week postpartum and evaluate their relationship with the presentation of endometritis in housed dairy cows. In this prospective longitudinal observational study, 467 cows from 3 farms in Lima-Peru were studied. Blood samples were collected from cows during the first week postpartum. Endometritis was diagnosed on day 35 ± 3 days postpartum by evaluation of vaginal discharge samples. The samples were obtained using the MetricheckTM device (Simcro, New Zealand). Two cut-off points were used to diagnose endometritis: a) endometritis metricheck score ≥ 3, and b) endometritis metricheck score ≥ 2. In the univariate model that considers a SC threshold of 5.25 to 8.75 mg/dL (1.31 to 2.18 mmol/L), a significant relationship (p < 0.05) was found for endometritis metricheck score ≥ 3, while no significant relationship was found (p = 0.12) with endometritis metricheck score ≥ 2. In both cases, the optimal SC threshold for the appearance of endometritis was determined to be a value ≥7.0 mg/dL (≥1.75 mmol/L). In the logistic regression models (parity, calving season, calcium level, and their interaction), only two variables were retained, parity and calcium level (p < 0.10). It was found that the probability of having endometritis metricheck score ≥ 3 was 1.9 (95% CI: 1.1 to 3.1), whereas the probability of having endometritis metricheck score ≥ 2 was 1.5 (95% CI: 1.0 to 2.5) in cows with calcium levels <7.0 mg/dL (<1.75 mmol/L). In conclusion, cows with calcium levels <7.0 mg/dL (<1.75 mmol/L) have a 1.9-fold greater risk of developing endometritis metricheck score ≥ 3 in the first week postpartum.

Vulnerability to climate change of a microendemic lizard species from the central Andes.

Given the rapid loss of biodiversity as consequence of climate change, greater knowledge of ecophysiological and natural history traits are crucial to determine which environmental factors induce stress and drive the decline of threatened species. Liolaemus montanezi (Liolaemidae), a xeric-adapted lizard occurring only in a small geographic range in west-central Argentina, constitutes an excellent model for studies on the threats of climate change on such microendemic species. We describe field data on activity patterns, use of microhabitat, behavioral thermoregulation, and physiology to produce species distribution models (SDMs) based on climate and ecophysiological data. Liolaemus montanezi inhabits a thermally harsh environment which remarkably impacts their activity and thermoregulation. The species shows a daily bimodal pattern of activity and mostly occupies shaded microenvironments. Although the individuals thermoregulate at body temperatures below their thermal preference they avoid high-temperature microenvironments probably to avoid overheating. The population currently persists because of the important role of the habitat physiognomy and not because of niche tracking, seemingly prevented by major rivers that form boundaries of their geographic range. We found evidence of habitat opportunities in the current range and adjacent areas that will likely remain suitable to the year 2070, reinforcing the relevance of the river floodplain for the species' avoidance of extinction.

Comparison across 12 countries on knowledge, attitude, and behavior scores about medication errors in Intensive Care Units: an international study.

OBJECTIVE: The aim of the study was to explore the degree of agreement of intensive care unit nurses working on a set of medication error preventive strategies and to examine possible predictors of nurses' knowledge, attitude and behavior. MATERIALS AND METHODS: Observational, international, and cross-sectional study. Iran, Malta, Spain, Pakistan, Nepal, Qatar, Ecuador, Australia, Finland, Italy, Egypt, and Jordan were the countries included in this survey. To collect data, the Knowledge, Attitude and Behavior in Medication Errors questionnaire was used. A descriptive statistical analysis was performed for the socio-demographic characteristics of the sample and three multiple logistic regressions were performed. RESULTS: The international sample consists of 1383 nurses, of whom 478 (34.6%) were men and 900 (65.1%) were women and their mean age was 35.61 years with a range of 19-61. Descriptive statistics conducted on the international sample show a medium to high degree of agreement among participants concerning some preventive strategies of medication error. In addition, the results of the present study show a strong relationship between positive nurses' attitudes and correct behaviors and/or adequate knowledge, as well as between adequate knowledge and correct behaviors (p< 0.01). CONCLUSIONS: Further studies are needed to explore the issue of medication error concerning nurses' cultural backgrounds, as well as to assess similarities and disparities among international nurses.

Mercury in air and plant specimens in herbaria: a pilot study at the MAF Herbarium in Madrid (Spain).

We present data from a study of mercury concentrations in air and plant specimens from the MAF Herbarium in Madrid (Spain). Hg (gas) emissions from old plant collections treated with mercuric chloride (HgCl(2)) in herbaria may pose a health risk for staff working in installations of this type. This is an issue not yet properly addressed. Plants that underwent insecticide treatment with HgCl(2) at the MAF Herbarium until the mid 1970s have persistent high concentrations of Hg in the range 1093-11,967 microg g(-1), whereas untreated specimens are in the range of 1.2-4.3 microg g(-1). The first group induces high concentrations of Hg (gas) in the main herbarium room, with seasonal variations of 404-727 ng m(-3) (late winter) and 748-7797 ng m(-3) (early summer) (baseline for Hg: 8 ng m(-3)). A test survey at another herbarium in Madrid showed even higher concentrations of Hg (gas) above 40,000 ng m(-3). The World Health Organization guidelines for chronic exposure to Hg (gas) are estimated at a maximum of 1000 ng m(-3). While staff was aware of the existence of HgCl(2) treated plants (the plant specimen sheets are labelled as 'poisoned'), they had no knowledge of the presence of high Hg (gas) concentrations in the buildings, a situation that may be relatively common in herbaria.

Escuchando a los abuelos: transdisciplina, aves y gente para cultivar la memoria biocultural / Listening to elders: transdisciplinarity, birds and people to cultivate biocultural memory / Ouvindo os avós: transdisciplina, pássaros e pessoas para cultivar a memória biocultural

Resumen (analítico) Presentamos una iniciativa y proponemos una metodología transdisciplinaria para cultivar la memoria biocultural, basada en los procesos de participación y materialización en comunidades de práctica (educativas). Presentamos el proyecto «Escuchando a los abuelos¼, que buscó facilitar diálogos intergeneracionales en tres escuelas mapuche (~ 90 niños y niñas) en Wallmapu, Chile. «Escuchando a los abuelos¼ utilizó a las aves como protagonistas de narrativas locales sobre el territorio. Cocreamos un ciclo de cinco pasos para promover la participación y la materialización. Los niños y niñas desarrollaron un ejercicio de abstracción para dar significado a las narrativas que ellos mismos recopilaron para crear memes positivos sobre las aves. Estos memes fueron comunicados dentro y más allá de sus comunidades. Concluimos que la experiencia de los abuelos debe ser honrada para contrarrestar la actual extinción de la experiencia biocultural.

Abstract (analytical) This article presents an initiative and proposes a transdisciplinary methodology to cultivate biocultural memory based on the processes of participation and materialization in (educational) communities-of-practice. We implemented the project "Listening to elders" that sought to facilitate intergenerational dialogues in three mapuche schools (with approximately 90 children) in Wallmapu, Chile. Listening to elders used birds as the basis of constructing local narratives about the territory. We co-created a 5-Step cycle to promote participation and materialization. The children participated in an abstraction exercise to give meaning to the narratives they constructed themselves to create positive memes involving birds. These memes were communicated within and beyond their communities. The authors conclude that the experiences of elders must be honored in communities to counter the current dynamic involving the extinction of biocultural experience.

Resumo (analítico) Apresentamos uma iniciativa e propomos uma metodologia transdisciplinar para o cultivo da memória biocultural, baseada nos processos de participação e materialização, em comunidades de prática (educacionais). Apresentamos o projeto «Escutando os avós¼ que buscou facilitar o diálogo intergeracional em três escolas mapuche (~ 90 crianças) em Wallmapu, Chile. «Ouvir os avós¼ usou os pássaros como base para as narrativas locais sobre o território. Co-criamos um ciclo de cinco passos para promover a participação e materialização. As crianças desenvolveram um exercício de abstração para dar sentido às narrativas que elas próprias coletaram para criar memes positivos sobre pássaros. Esses memes foram comunicados dentro e fora de suas comunidades. Concluímos que a experiência dos avós deve ser honrada para conter a atual extinção da experiência biocultural.

Crystal structure of a Fab complex formed with PfMSP1-19, the C-terminal fragment of merozoite surface protein 1 from Plasmodium falciparum: a malaria vaccine candidate.

Merozoite surface protein 1 (MSP1) is the major protein component on the surface of the merozoite, the erythrocyte-invasive form of the malaria parasite Plasmodium. Present in all species of Plasmodium, it undergoes two distinct proteolytic maturation steps during the course of merozoite development that are essential for invasion of the erythrocyte. Antibodies specific for the C-terminal maturation product, MSP1-19, can inhibit erythrocyte invasion and parasite growth. This polypeptide is therefore considered to be one of the more promising malaria vaccine candidates. We describe here the crystal structure of recombinant MSP1-19 from P.falciparum (PfMSP1-19), the most virulent species of the parasite in humans, as a complex with the Fab fragment of the monoclonal antibody G17.12. This antibody recognises a discontinuous epitope comprising 13 residues on the first epidermal growth factor (EGF)-like domain of PfMSP1-19. Although G17.12 was raised against the recombinant antigen expressed in an insect cell/baculovirus system, it binds uniformly to the surface of merozoites from the late schizont stage, showing that the cognate epitope is exposed on the naturally occurring MSP1 polypeptide complex. Although the epitope includes residues that have been mapped to regions recognised by invasion-inhibiting antibodies studied by other workers, G17.12 does not inhibit erythrocyte invasion or MSP1 processing.

[Monitoring of vancomycin plasma levels in patients undergoing hemodialysis]. / Monitorización de las concentraciones plasmáticas de vancomicina en pacientes en hemodiálisis.

OBJECTIVE: The aim of this study was to confirm whether patients undergoing dialysis and treated with vancomycin 1 g/week or 500 mg/48 hours reach optimum plasma levels (10-25 mcg/ml). METHOD: Thirty two patients were included with a total number of 34 infectious events. The most commonly used dose was 1 g/week (67.6% of infectious events), versus 500 mg/48 hours (32.4%). Low ultrafiltration membranes were used more frequently (64.7%) than high ultrafiltration membranes (35.3%).Vancomycin was infused over an one-hour period during the last hour of the hemodialysis session and plasma samples were drawn prior to the beginning of the session. Samples were analyzed using fluorescent polarization immunoassays. RESULTS: Mean concentration results for the total population did not reach optimum values (10-25 mg/ml). In the group receiving 500 mg/48 hours, optimum mean values were not reached in any of the determinations, whereas in the group receiving 1 g/week, optimum values were reached in the fourth determination. Mean plasma levels of the antibiotic were below optimum values, regardless the type of membrane used, either low or high ultrafiltration. CONCLUSIONS: Based on the above results, we recommend titration of the vancomycin dose in this group of patients and the administration of a loading dose of 20 mg/kg during the last hour of the hemodialysis session, followed by a maintenance dose of 7 mg/kg after each session, as well as the monitoring of the drug levels in this group of patients.

Embarazo en enfermedad inflamatoria intestinal: no solo 9 meses de cuidado

The prevalence of inflammatory bowel disease (IBD) increased in the last decades. Thus, the number of pregnant women with the condition is also increasing. Given that active disease itself is the main risk factor for complications during pregnancy, it is necessary to achieve a complete remission before planning a pregnancy. Also, pregnant women with IBD must be monitored noninvasively and be treated proactively, including escalated therapies, if needed, to prevent potential flares during pregnancy. Patients can undergo vaginal delivery in most forms of IBD. However, cesarean delivery is still preferable in women with a history of ileal pouch-anal anastomoses (IPAA) or active perianal disease.

Recomendaciones para el manejo de pacientes con enfermedad Inflamatoria Intestinal (EII) y COVID-19 / Recommendations for the management of patients with Inflammatory Bowel Disease (IBS) and COVID-19

The new Coronavirus (SARS-CoV-2) appeared in China in December 2019. Since then and until April 2020 it spread worldwide affecting more than three million people. Its exponential rise is still growing all over the world, taking thousands of lives. SARS-CoV-2 is very contagious, person to person, by droplets which can generate a respiratory infection known as COVID-19. Some patients are at higher risk: Older people, those with cardiovascular disease, diabetes and hypertension are the most prone to an unfavorable outcome. Our Inflammatory Bowel Disease (IBD) patients are a special cluster, with many of them taking immunosuppressive treatment for long periods, which could pose an important risk. Scientifics societies all over the world have joined efforts to generate data, share experiences and make recommendations for good clinical management. This is a review of the available evidence, expert opinion, and proposed ways of working during the pandemic

El nuevo coronavirus (SARS-CoV-2) apareció en China en diciembre de 2019. Desde su inicio hasta abril de 2020 se ha expandido por todo el mundo, afectando a más de tres millones de personas. Su ascenso exponencial sigue creciendo, generando miles de muertes. Su contagiosidad es persona a persona por gotitas, pudiendo llegar a generar un cuadro clínico de infección respiratoria conocido como COVID-19. Algunos pacientes tienen más riesgos de tener un curso desfavorable; adultos mayores, pacientes con enfermedad cardiovascular, hipertensos y diabéticos. Nuestros pacientes con enfermedad inflamatoria intestinal son un grupo de pacientes con características particulares, muchos de ellos reciben tratamiento inmunosupresor por largos períodos, lo que pudiese suponer un riesgo específico. Las sociedades científicas de Europa y Norteamérica han realizado un esfuerzo conjunto para generar datos, compartir experiencias y dictar recomendaciones de buen manejo clínico. Esta es una revisión de la evidencia disponible, opiniones de expertos y formas de trabajo propuestos durante la pandemia.

Structural and functional characterization of a monoclonal antibody specific for the preS1 region of hepatitis B virus.

The monoclonal antibody 5a19, raised against the ay serotype of hepatitis B virus, binds to the segment of the preS1 region comprising residues 37-43, which is implicated in attachment of the virus to hepatocytes. The dissociation constant, derived from kinetic studies using surface plasmon resonance techniques, is in the low nanomolar range. The nucleotide sequence of the variable domains has been determined and the corresponding germ-line genes have been identified. The three-dimensional structure of the Fab fragment has been determined by X-ray crystallography to 2.6 A resolution.

Metabolic acidosis in advanced renal failure: differences between diabetic and nondiabetic patients.

Metabolic acidosis is almost invariably a consequence of advanced renal failure, although its severity can vary widely. To evaluate the determinants of the severity of metabolic acidosis, with special interest in determining if there is any difference in the prevalence and severity of metabolic acidosis between patients with and without diabetes, 113 predialysis patients with renal failure were studied. Criteria for inclusion onto the study were: creatinine clearance (Ccr)/1.73 m2 less than 30 mL/min, no alkali therapy within the previous 30 days, and the absence of respiratory diseases. Forty-eight patients had diabetes (33 patients with diabetic nephropathy). The following data were analyzed: demographics; cause of renal failure; hematocrit; serum urea, creatinine, uric acid, albumin, glucose, hemoglobin A1c, bicarbonate, sodium, potassium, chloride, calcium, phosphorus, and alkaline phosphatase levels; anion gap; urinary protein excretion; Ccr/1.73 m2; half of the sum of creatinine and urea clearances (Ccr-Cu); protein-equivalent nitrogen appearance (PNA); and whether the patients received diuretics (75 patients), angiotensin-converting enzyme inhibitors (54 patients), and/or calcium channel blockers (55 patients). After the exclusion of eight patients because of hypochloremia (three patients with and five patients without diabetes), mean serum bicarbonate levels were significantly greater in patients with diabetes than in the rest of the patients (20.7 +/- 2.3 v 18.2 +/- 2. 3 mmol/L; P = 0.0001). The mean anion gap (mmol/L) was also significantly less in patients with than without diabetes (19.70 +/- 3.65 v 22.35 +/- 3.64; P = 0.003). Eleven of 105 patients had serum bicarbonate levels of 23 mmol/L or greater (9 patients with and 2 patients without diabetes). Pure elevated anion gap followed by mixed (high anion gap and hyperchloremia) were the most common types of metabolic acidosis observed in both groups. There were no differences in PNA, diuretic treatment, or vomiting history between patients with and without diabetes. By multiple logistic regression analysis, the best determinants for a serum bicarbonate level greater than 19 mmol/L were: the diagnosis of diabetic nephropathy (odds ratio, 0.107; P = 0.0002), Ccr-Cu (odds ratio, 0.824; P = 0. 014), and age (odds ratio, 0.966; P = 0.046). In conclusion, patients with diabetes with advanced renal failure showed a less severe metabolic acidosis, which cannot be explained by gastrointestinal hydrogen ion losses, drugs, or reduced protein catabolic rate. Patients with diabetes may have a more efficient extrarenal generation of bicarbonate than end-stage renal failure patients without diabetes.

Modulation of respiratory rhythm by alpha 2-adrenoceptors in awake and anesthetized goats.

The purpose of this study was to examine the effects of alpha 2-adrenoceptor agonists in the control of breathing with goats that were either awake (n = 7) or anesthetized and artificially ventilated (n = 11). Awake goats infused intravenously with either of the alpha 2-agonists clonidine (1.0-6.0 micrograms/kg) or guanabenz (15.0-63.0 micrograms/kg) exhibited two distinct ventilatory patterns. One pattern was characterized by tachypnea in which respiratory frequency and minute ventilation increased to approximately 50% above control values. A second ventilatory pattern consisted of slow breathing with reductions of respiratory frequency and minute ventilation and highly variable expiratory duration intervals. These two patterns were unaffected by bilateral carotid body denervation. In anesthetized goats, alpha 2-agonists also caused an arrhythmia in phrenic nerve activity that was similar to the slow breathing pattern seen in awake goats. Respiratory disturbances were abolished by the selective alpha 2-receptor antagonist SKF-86466 (100-500 micrograms/kg), indicating that the effects are mediated by alpha 2-receptors. The results suggest that stimulation of alpha 2-adrenoceptors generally has an inhibitory effect on breathing in goats. The disruption of ventilation with clonidine or guanabenz suggests that alpha 2-adrenoceptors may play an important role in the control of central respiratory rhythm.