Characterization of inflammatory bowel disease in Colombia: Results of a national register. / Caracterización de la enfermedad inflamatoria intestinal en Colombia: resultados de un registro nacional.

AIM: To determine the clinical, sociodemographic, and treatment characteristics of inflammatory bowel disease (IBD) in a Colombian population register. METHODS: A descriptive, analytic, observational, cross-sectional, multicenter study on patients with IBD from 17 hospital centers in 9 Colombian cities was conducted. RESULTS: A total of 2,291 patients with IBD were documented, 1,813 (79.1%) of whom presented with ulcerative colitis (UC), 456 (19.9%) with Crohn's disease (CD), and 22 with IBD unclassified (0.9%). The UC/CD ratio was 3.9:1. A total of 18.5% of the patients with UC and 47.3% with CD received biologic therapy. Patients with extensive UC had greater biologic therapy use (OR = 2.78, 95% CI: 2.10-3.65, p = 0.000), a higher surgery rate (OR = 5.4, 95% CI: 3.5-8.3, p = 0.000), and greater frequency of hospitalization (OR = 4.34, 95% CI: 3.47-5.44, p = 0.000). Patients with severe UC had greater biologic therapy use (OR = 5.04, 95% CI: 3.75-6.78, p = 0.000), a higher surgery rate (OR = 8.64, 95% CI: 5.4-13.78, p = 0.000), and greater frequency of hospitalization (OR = 28.45, 95% CI: 19.9-40.7, p = 0.000). CD patients with inflammatory disease behavior (B1) presented with a lower frequency of hospitalization (OR = 0.12, 95% CI: 0.07-0.19, p = 0.000), a lower surgery rate (OR = 0.08, 95% CI: 0.043-0.15, p = 0.000), and less biologic therapy use (OR = 0.26, 95% CI: 0.17-0.41, p = 0.000). CONCLUSION: In Colombia, there is a predominance of UC over CD (3.9:1), as occurs in other Latin American countries. Patients with extensive UC, severe UC, or CD with noninflammatory disease behavior (B2, B3) have a worse prognosis.

Dataset on electrochemical reduced graphene oxide production: Effect of synthesis parameters.

Structural and microstructural characterization combined with vibrational, rotational modes are quite important to determinate reduction degree during synthesis of reduced graphene oxide. These data and analysis support the research article "Electrochemical alternative to obtain reduced graphene oxide by pulse potential: effect of synthesis parameters and study of corrosion properties" (López-Oyama et al., 2018). The data and analysis presented here included raw data for selected reduction potentials (V SCE) and different temperatures values (°C). Transmission electron microscopy (TEM) images of the exfoliated graphite are shown to corroborate the effect of the applied voltage to obtain electrochemically reduced graphene oxide (ERGO) on commercial 304L stainless steel (304L SS). The data provided in this article has not been previously published and are available to enable critical or extended analyses.

Structure, electronic properties, and aggregation behavior of hydroxylated carbon nanotubes.

We present a combined experimental and theoretical study to analyze the structure, electronic properties, and aggregation behavior of hydroxylated multiwalled carbon nanotubes (OH-MWCNT). Our MWCNTs have average diameters of ~2 nm, lengths of approximately 100-300 nm, and a hydroxyl surface coverage θ~0.1. When deposited on the air/water interface the OH-MWCNTs are partially soluble and the floating units interact and link with each other forming extended foam-like carbon networks. Surface pressure-area isotherms of the nanotube films are performed using the Langmuir balance method at different equilibration times. The films are transferred into a mica substrate and atomic force microscopy images show that the foam like structure is preserved and reveals fine details of their microstructure. Density functional theory calculations performed on model hydroxylated carbon nanotubes show that low energy atomic configurations are found when the OH groups form molecular islands on the nanotube's surface. This patchy behavior for the OH species is expected to produce nanotubes having reduced wettabilities, in line with experimental observations. OH doping yields nanotubes having small HOMO-LUMO energy gaps and generates a nanotube → OH direction for the charge transfer leading to the existence of more hole carriers in the structures. Our synthesized OH-MWCNTs might have promising applications.

[Characteristics of drug interactions in a pediatric intensive care unit]. / Características de las interacciones farmacológicas en una unidad de cuidados intensivos de pediatría.

INTRODUCTION: The aim of this study is to calculate the theoretical frequency of potential drug interactions (PDI) and their characteristics in the therapeutic plan of hospitalized patients in a Pediatric Intensive Care Unit (PICU). PATIENTS AND METHODS: An observational study was conducted which analyzed PICU prescriptions between September and November 2011. The inclusion criteria included to be hospitalized in a PICU, requirements of at least 3 drugs, except those topically applied, either gender, no age limit, no hospital stay required. The Micromedex® 2.0 program was used to detect and classify PDI. RESULTS: Of 223 patients, 100 met inclusion criteria, 610 prescriptions were analyzed and 815 drugs were prescribed. 1,240 PDI were detected in 44 patients; 12 patients received more than 10 drugs each, presenting 1,162 PDI (93.7% of total PDI). 8 patients were hospitalized for more than 10 days, presenting 1,035 PDI (83.5% of total PDI). According to PDI theoretical severity, 37.5% were high, 51.7% moderate, 6.7% low and 4.1% contraindicated. The therapeutic group most involved was antimicrobials (17.6%) and the most frequently involved individual drugs were chloral hydrate (15.9%), midazolam (14.1%) and vecuronium (13.4%). CONCLUSION: PDI were more frequent in patients associated with major polypharmacy and longer hospital stay.

Homeostatic control of conjunctival mucosal goblet cells by NKT-derived IL-13.

Although the effects of the interleukin 13 (IL-13) on goblet cell (GC) hyperplasia have been studied in the gut and respiratory tracts, its effect on regulating conjunctival GC has not been explored. The purpose of this study was to determine the major IL-13-producing cell type and the role of IL-13 in GC homeostasis in normal murine conjunctiva. Using isolating techniques, we identified natural killer (NK)/natural killer T (NKT) cells as the main producers of IL-13. We also observed that IL-13 knockout (KO) and signal transducer and activator of transcription 6 knockout (STAT6KO) mice had a lower number of periodic acid Schiff (PAS)+GCs. We observed that desiccating stress (DS) decreases NK population, GCs, and IL-13, whereas it increases interferon-γ (IFN-γ) mRNA in conjunctiva. Cyclosporine A treatment during DS maintained the number of NK/NKT cells in the conjunctiva, increased IL-13 mRNA in NK+ cells, and decreased IFN-γ and IL-17A mRNA transcripts in NK+ and NK- populations. C57BL/6 mice chronically depleted of NK/NKT cells, as well as NKT cell-deficient RAG1KO and CD1dKO mice, had fewer filled GCs than their wild-type counterparts. NK depletion in CD1dKO mice had no further effect on the number of PAS+ cells. Taken together, these findings indicate that NKT cells are major sources of IL-13 in the conjunctival mucosa that regulates GC homeostasis.

El militar quemado / The «burned-out» service member

En los últimos tiempos, se ha puesto de moda en medicina el empleo de un término que cada vez atrae a más estudiosos y especialistas: el síndrome burnout, que se podría traducir por la más coloquial expresión de síndrome del «quemado» por cuestiones relacionadas con el trabajo. Sin embargo, y a pesar de la enorme infl uencia que este síndrome puede tener en la efi cacia de las Fuerzas Armadas, no prolifera la literatura especializada que trate en profundidad en qué medida el profesional militar español puede estar afectado, cuáles podrían ser las causas de su implantación en el seno castrense y los efectos y las consecuencias que de ellas se derivarían. El objeto de este estudio es, precisamente, alertar sobre la alta probabilidad de que un número creciente de militares españoles sean víctimas de este síndrome, concienciar a los responsables correspondientes de la necesidad de adoptar medidas paliativas y correctoras, abrir los ojos a los propios afectados sobre la perentoria urgencia de su tratamiento y, en fi n, crear una inquietud para que futuros expertos e investigadores, principalmente psiquiatras y psicólogos, profundicen en el tema y aconsejen y aporten vías de solución, tanto preventivas como en forma de efi caces tratamientos. Una de las conclusiones ineludibles va a ser que es imprescindible efectuar valoraciones periódicas entre diversos grupos de militares de todos los empleos y en diferentes destinos, con la fi nalidad de determinar la prevalencia del síndrome e identifi car sus factores profesionales asociados. Además, se antoja todavía más obligatorio, si cabe, realizar este tipo de estudios en absolutamente todo el personal que regrese de una misión en el exterior (independiente de la consideración ofi cial que tenga) y en los integrantes de unidades (muy concretamente en el de la Unidad Militar de Emergencias) que hayan pasado por una experiencia extrema o que hayan mantenido un alto grado de involucración en diversas operaciones de apoyo a la población civil en territorio nacional. Tampoco se debe olvidar el preciso seguimiento en el tiempo de este personal, así como del contacto con sus familiares más allegados, que darán el pulso de la verdadera actitud del profesional en los ámbitos donde éste actúa con mayor naturalidad y espontaneidad. Sin duda, ser militar en la sociedad actual supone aceptar realidades y desarrollar estrategias que protejan al profesional de los riesgos psicológicos de su actividad. Pero ello implica la participación activa de los servicios médicos, psiquiátricos y psicológicos de las Fuerzas Armadas. El aviso está dado, sólo queda la voluntad, por parte de quien le corresponda, de poner en marcha los mecanismos pertinentes (AU)

Lately the fashion in medicine is to utilize an expression that attracts more and more experts and specialists: the burnout syndrome, which could be translated by the colloquial expression «síndrome del quemado» for job-related issues. However, and in spite of the huge impact that this syndrome could have on the effi cacy of the Armed Forces there is not an abundance of specialized literature dealing in depth on how it affects Spanish military personnel, which could be the causes of its appearance in the military environment and its effects and derived consequences. The objective of this study is precisely to emphasize the high probability that an increasing number of Spanish service members will become victims of this syndrome, to increase the awareness among the responsible people of the need to adopt palliative and correcting measures, to inform the affected personnel about the urgency of the treatment, and fi nally to raise the concern so that future experts and researchers, mainly psychiatrists and psychologists, study in depth this subject and advise on approaches, preventive and therapeutical. One unavoidable conclusion will be that it is necessary to carry out periodic evaluations among the different groups of service members of all ranks and different appointments so as to determine the prevalence of the syndrome and identify its associated professional factors. Moreover, it seems even more compulsory, if anything, to perform these studies in absolutely all personnel coming back from a foreign deployment (no matter what is its offi cial consideration) and in the members of those units (more specifi cally in the Emergency Military Unit) that have experienced an extreme situation or have become highly involved in different support operations to the populace in the national territory. Neither should it be forgotten to execute a rigorous follow-up of these personnel, and also keep in touch with their closest relatives, as they will provide useful insights in the true attitude of the service members in the environment where they act more spontaneously and naturally. There is no doubt that in today’s society to be in the military implies to accept facts and develop protective strategies against the psychological risks of this profession. But that requires the active participation of the medical services, psychiatric and psychological, of the Armed Forces. The warning has already sounded, now someone responsible should initiate the appropriate procedures (AU)

Rheology of the Pluronic P103/water system in a semidilute regime: evidence of nonequilibrium critical behavior.

The linear and nonlinear rheological behaviors of semidilute aqueous solutions of the amphiphile triblock polymer Pluronics P103 in water are reported here. For C(surf) < or = 20 wt%, micelles are spherical at temperatures lower than ca. 27 degrees C and grow with increasing temperature to form long polymer-like micelles. These polymer-like micelles exhibit strong viscoelasticity and a shear-banding region that shrinks as the cloud point is approached. Master time-temperature-concentration curves were obtained for the dynamic moduli using traditional shifting factors. In the nonlinear regime, P103 polymer-like micellar solutions follow the master dynamic phase diagram proposed by Berret and colleagues, in which the flow curves overlap in the low-shear-rate homogeneous flow region. Within the nonhomogeneous flow region (confirmed by flow birefringence and small-angle light-scattering measurements), oscillations and overshoots are detected at the inception of shear flow, and two main relaxation mechanisms are apparent after cessation of steady shear flow. Evidence for nonequilibrium critical behavior is presented, in which the order parameter is the difference of critical shear rates that limit the span of the plateau stress. Most of the steady-state and transient features of the nonlinear rheology of the P103 polymer-like micelles are reproduced with the Bautista-Manero-Puig (BMP) model, including the predictions of nonequilibrium critical behavior under flow.

Phase behavior of the Pluronic P103/water system in the dilute and semi-dilute regimes.

The detailed temperature-composition phase diagram of the P103/water system in the dilute and semidilute regions is reported here using density and ultrasound velocity measurements, differential scanning calorimetry (DSC), rheometry and dynamic (DLS) and static light scattering (SLS). These techniques allow a precise determination of the critical micellar temperature (CMT), the sphere-to-rod micellar transition temperature (GMT) and the cloud point temperature (CPT) as a function of concentration. DLS and SLS measurements were employed to gain information on unimers and aggregate sizes and on the transition from spherical-to-rod micelles.

Validación de la Escala de Depresión de Zung en personas con VIH / Validation of the Zung Depression Scale in persons with HIV

Se describen las propiedades psicométricas de la escala de depresión de Zung, que fue administrada a 62 personas con VIH que al momento del estudio eran vistos en el Centro Ambulatorio para la Prevención y Atención a VIH/SIDA e ITS en la ciudad de Hermosillo, México. La edad promedio de los participantes fue de 37,02 años, de los cuales 59,7 por ciento eran personas del sexo masculino y 40,3 por ciento del sexo femenino. Para la evaluación de las propiedades psicométricas de la escala se utilizaron en orden sucesivo los siguientes procedimientos: la prueba de la t de Student de comparación de medias para la comprensión de las preguntas; un análisis factorial exploratorio con rotación varimax para estudiar la validez de constructo y el coeficiente a de Cronbach para valorar la confiabilidad. Con la prueba de la t de Student se obtuvieron valores de significancia estadística en 19 de las 20 preguntas. El análisis factorial exploratorio arrojó una estructura de tres factores, con valores propios superiores a 1 y que en conjunto explican 56,13 por ciento) de la varianza. Finalmente, en el análisis de confiabilidad de la medida se obtuvo un a de Cronbach global de 0.887. Según los resultados obtenidos, la escala de depresión de Zung posee óptimas propiedades psicométricas de validez de constructo y confiabilidad en personas con VIH.

We describe the psychometric properties of the Zung's depression scale, which was administered to 62 persons with HIV who were being treated in the Ambulatory Center of Prevention and Attention at HIV/AIDS and STI in Hermosillo, Mexico. Participants mean age was 37.02 year old, 59.7 percent> were male and 40.3 percent> females. Three consecutive statistical testing procedures were applied for data analysis: the Student t test for comparison of means and for assesing the comprehensibility of the questions; an exploratory factorial analysis with varimax rotation for determining construct validity; Cronbach's a coefficient for determining reliability. In 19 out of a total of 20 questions, the Student t test for comparison of means gave statistically significant values. A three-factors structure was found with the factorial analysis, with values above 1 that, taken as a whole, explain 56.13 percent> of the variance. An overall a coefficient of 0.887 was obtained with the test of reliability. According with the results obtained, the Zung' depression scale has optimal psychometric properties of construct validity and reliability for people with HIV

Levels of mucin gene expression in normal human conjunctival epithelium in vivo.

PURPOSE: Conjunctival impression cytology (CIC) samples were used to determine the mean and normal range of mRNA levels of human MUC1, MUC2, MUC4, MUC5AC, and MUC7 mucin genes. METHODS: Real time PCR was performed to determine normal mRNA levels in CIC samples of 24 male and 19 female healthy donors. Correlation coefficients between gene expression levels were obtained. RESULTS: All five mucin genes were expressed in the CIC samples. MUC1 and MUC4 were present at the highest level and MUC2 was at the lowest. There were no gender differences. Significant positive correlations existed between MUC2 and MUC4 and between MUC2 and MUC7 levels. CONCLUSIONS: Normal levels and ranges of mRNAs for MUC1, MUC2, MUC4, MUC5AC and MUC7 conjunctival mucin genes have been established for the first time. These data may serve as the normal threshold values for future comparisons in different experimental and pathological conditions involving the ocular surface.

[Normal human conjunctival epithelium expresses MUC13, MUC15, MUC16 and MUC17 mucin genes]. / Expresión de los genes de mucinas MUC13, MUC15, MUC16 y MUC17 en el epitelio conjuntival normal humano in vivo.

PURPOSE: The ocular surface epithelia express at least five mucin genes of the total of 17 human mucin genes that have been identified so far. This study was designed to determine the expression profile of mucin genes in conjunctival impression cytology (CIC) samples from healthy subjects. METHODS: Two polyethersulfone filters were applied to the superior conjunctiva of both eyes from eight healthy donors. Polymerase chain reaction (PCR) was performed using isolated and retrotranscripted total RNA obtained from the CIC samples to study the expression of all known human mucin genes. Following amplification, PCR products were electrophoresed on 1.5% agarose gel and stained with ethidium bromide to confirm that only a single band was obtained when amplifying all cDNAs with the convenient primers. RESULTS: Transcripts of the previously reported conjunctival mucin genes MUC1, MUC2, MUC4, MUC5AC, and MUC7 were detected in all samples. In addition, transcripts of MUC13, MUC15, MUC16 and MUC17 mucin genes also were detected. Amplified products by conventional PCR showed the expected amplicon size. Transcripts of MUC3A, MUC3B, MUC5B, MUC6, MUC8, MUC11, and MUC12 mucin genes were not detected. CONCLUSION: The expression of four additional mucin mRNA (MUC13, MUC15, MUC16, and MUC17) has been proved in human conjunctival epithelium from healthy donors for the first time. The function of these genes remains to be further elucidated.

[In vitro toxicity of non-preserved artificial-tear formulations]. / Lágrimas artificiales sin conservantes: estudio comparativo in vitro.

PURPOSE: To analyse the putative toxic effect of three commercially available non-preserved artificial tear formulations on in vitro human conjunctival cells. MATERIAL AND METHOD: A conjunctival human epithelial cell line was exposed to Cellufresh, Oculotect and Acuolens formulations during 1, 3 and 24 hours. Cytotoxicity was measured by calculating the percentage of cell viability examination and scanning electron microscopy (SEM). Controls underwent exposure to supplement free DMEM-F12 (negative control) and exposure to 0.005% benzalkonium chloride solution (positive control). RESULTS: Cell viability after 1 or 3 hours incubation with Cellufresh and Oculotect was similar to that obtained for negative controls. With Acuolens incubation however, cell viability showed significant reduction after 3 and 24 hours compared to control. SEM showed that Cellufresh and Oculotect exposed cells presented similar behavior to control cells. All three cell lines presented evidence of cellular surface alteration after incubation for 1 or 3 hours compared to controls, Acuolens showing the highest rate of alterations in exposed cells and an additional increment in cell loss was observed. CONCLUSION: In the present study, non preserved artificial tears formulations showed a different degree in their in vitro toxicity, Acuolens being more toxic than Cellufresh or Oculotect.

Prescription of antibiotics for mild acute respiratory infections in children.

Acute respiratory infections (ARI), the leading class of ailments causing people to seek health care, rarely require antibiotics. Nevertheless, many physicians prescribe them needlessly. Hence, reducing the unnecessary use of antibiotics is one aim of any ARI control program. To help determine whether this aim might be achieved through a combination of refresher training for family physicians and public education campaigns, two 1991 interventions were carried out in four health areas (designated A, B, C, and D) in the city of Havana, Cuba. In each area, 10 clinics staffed by family physicians were selected through simple random sampling. In two areas (A and B), a refresher training program on ARI for health personnel was instituted at each clinic, while in areas A and C a community education program was set up. No intervention was carried out in area D. Simultaneously, from January through December 1991 trained individuals visited and administered a standard questionnaire every 15 days to 1,600 families (40 per clinic) systematically selected by random sampling. The aim of this procedure was to record the number of ARI episodes occurring among children under 5 years old, the treatment chosen in these cases, and whether antibiotics were employed. The results showed that when the two interventions were initiated, antibiotics were prescribed for 26%, 20%, 11%, and 19% of the mild ARI cases occurring in areas A, B, C, and D respectively (P > 0.05). In the period immediately following the interventions, antibiotic prescription rates declined by 26% and 63% in areas A and B, while increasing by 2% and 48% in areas C and D. Overall, prescription of antibiotics in the intervention areas A and B combined decreased by 54% (95% CI: 31-69%). These data suggest that a refresher training program for health personnel can rapidly reduce the unnecessary prescribing of antibiotics for ARI cases, but that public education alone does not appear effective.

Cardiorespiratory reflex due to pulmonary J receptors stimulation by acetaldehyde in rats.

Acetaldehyde (AcH) administered intravenously or into the right ventricle induces reflex bradycardia, hypotension, and apnea in the rat. The efferent pathway for this reflex is vagal and probably secondary to pulmonary J receptors stimulation. Located between the alveoli and the pulmonary capillary, J receptors are accessible through the pulmonary circulation and the airways. For this reason, a method for indirect nebulization (IN) of AcH into the airways, that provides a continuous record of respiration without changes in intrapulmonary pressure, was developed. IN of AcH (n = 14) induced bradycardia (64 +/- 3.1%), hypotension (34 +/- 4.2%), and apnea (79%), which were blocked by vagotomy (n = 9). The latencies (s) for bradycardia (0.34 +/- 0.06), hypotension (0.68 +/- 0.11), and apnea (0.25 +/- 0.11) were significantly shorter than those obtained by the intravenous route. Three rats that did not develop apnea had an equivalent response, where both tidal volume and minute ventilation decreased about 40% and these effects were also blocked by vagotomy. Indirect nebulization of AcH allowed us to demonstrate that pulmonary J receptors are responsible for this reflex response.

[Volvulus of the colon. Presentation of 22 cases]. / Vólvulos del colon. Presentación de 22 casos.

A study was made of patients hospitalized with the diagnosis of colonic volvulus in two provincial hospitals of Camagüey during two different time periods (1979-1986 in the Amalia Simoni and 1978-1983 in the Manuel A. Domenech), for a total of 22 cases that represent 4.49% of the 489 patients admitted with a diagnosis of intestinal occlusion. We present 17 volvuli of the sigmoid, 4 ceco-ascendant and 1 transverse. Male sex and age over 70 years were strongly predominant. The principal symptoms were pain (90.9%) and abdominal distension (81.82%). Diagnosis was not reached in one patient who died in the preoperative period. Seventy-five percent of deaths had more than 72 hours of evolution. Several therapeutic procedures were used in this study, but all were considered emergency surgery according to our norms. Fifty percent of patients suffered complications, 38.46% of them wound infection. The mortality was 18.18%. A comparative study was made with other national and international series.

Histamine release and circulating cells after antigen inhalation in allergic dogs.

Histamine can be recovered from the blood of ragweed-sensitized dogs after aerosol antigen challenge, although its source is unknown. Neutrophils and eosinophils have been recovered from bronchoalveolar lavage fluid (BALF) obtained under identical conditions. We investigated the time course of changes in histamine levels in plasma and BALF taken from ragweed-sensitized dogs after aerosol challenge. Changes in the numbers of circulating neutrophils, eosinophils, lymphocytes, monocytes, and platelets were also studied. After 3 min, total pulmonary resistance (RL) was maximally increased and systolic blood pressure was maximally decreased. Histamine levels in plasma and BALF were increased and circulating eosinophils and neutrophils were decreased. After 15 min, platelet numbers were reduced. By 90 min, changes in RL, blood pressure, plasma and BALF histamine concentrations, and circulating neutrophils and eosinophils had returned to base-line values, but platelet numbers remained significantly decreased. Sham challenge caused no significant changes in any of these variables. Intravenous administration of histamine in doses large enough to attain plasma levels comparable with those achieved after aerosol antigen challenge resulted in no concomitant rise in BALF histamine levels. We conclude that antigen challenge in sensitized dogs causes increases in BALF and plasma histamine levels and is associated with a reduction in circulating neutrophils, eosinophils, and platelets. It is likely that antigen causes airway mast cells to release mediators that move down a concentration gradient from the airways to the pulmonary circulation.

Enkephalinase inhibitors potentiate substance P-induced secretion of 35SO4-macromolecules from ferret trachea.

To study the roles of substance P (SP) and endogenous peptidases in regulating mucus secretion from ferret trachea, we measured the SP-induced release of 35SO4-labeled macromolecules after incubating segments of trachea in Ussing chambers in the presence and absence of selected inhibitors of proteolytic enzymes. Our strategy was based on the idea that if endogenous peptidases degrade SP, then inhibitors of these enzymes should potentiate SP-induced secretion. We found that tracheas of ferrets contained SP-like immunoreactivity, and that SP stimulated the release of bound 35SO4 with rapid onset and offset. Eighty-five percent of the total macromolecular radioactivity released was contained in fractions of molecular weights greater than 10(6). The response to SP was concentration-dependent and reproducible. Thiorphan potentiated the secretory response to SP in a concentration-dependent fashion and phosphoramidon potentiated SP-induced secretion, whereas other inhibitors of proteinases and peptidases were without effects. These results suggest that substance P may regulate mucus secretion in ferrets, and that enkephalinase (dipeptidyl carboxypeptidase II, EC 3.4.24.11) in the airway degrades SP in a physiologically significant fashion, and thereby regulates peptide-induced secretion.

Ion transport across cat and ferret tracheal epithelia.

Sheets of trachea from ferret and cat were mounted in Ussing chambers and continuously short circuited. Under resting conditions, in both the cat and ferret there was little or no Cl secretion, and Na absorption accounted for most of the short-circuit current (Isc). Ouabain (10(-4) M, serosal bath) reduced Isc to zero in 30-60 min. This decline was matched by a decrease in net Na absorption. Amiloride (10(-4) M, luminal bath) caused a significant decrease in Isc and conductance (G) in both species. Bumetanide (10(-4) M, serosal bath) had negligible effects on Isc and G. In both species, isoproterenol increased Isc by stimulating Cl secretion. Methacholine induced equal amounts of Na and Cl secretion, with little change in Isc. In the cat, prostaglandins E2 and F2 alpha and bradykinin increased Isc, responses which were abolished in Cl-free medium. In open-circuited cat tissues, Na flux from the serosal to mucosal side was measured simultaneously with the secretion of nondialyzable 35S. Prostaglandins E1, E2, and F2 alpha, histamine, bradykinin, methacholine and isoproterenol all increased both Na and 35S-mucin secretion.