[Prevalence and risk factors for methicillin-resistant Staphylococcus aureus infection in children]. / Prevalencia y factores de riesgo de infección por Staphylococcus aureus resistente a meticilina en niños.

OBJECTIVE: The objectives of this work were to know the prevalence of methicillin-resistant S. aureus (MRSA) infections in the paediatric population of our health department, to describe the risk factors for infection by MRSA compared to those produced by methicillin-susceptible S. aureus (MSSA) and to know the antibiotic sensitivity profile of MRSA and MSSA isolates. METHODS: A retrospective, descriptive and analytical study of infections produced by MRSA versus those produced by MSSA was carried out during the years 2014 to 2018. Risk factors for MRSA infection were studied using a binary logistic regression model. RESULTS: 162 patients with S. aureus infections were identified. Of these, 25 (15.4%) were MRSA. The highest percentages of MRSA infection occurred among children who required hospital admission (23.4%). In the univariate analysis the need of hospital admission, antibiotic treatment in the last 3 months, the kind of infection and past MRSA infection or colonisation reached statistical significance. However, only the need of hospital admission and antibiotic treatment in the last 3 months maintained statistical significance in the binary logistic regression model. Correct antibiotic treatment was only prescribed in 26.7% of the MRSA infection cases admitted to the hospital. CONCLUSIONS: Our results suggest the need to review empirical local treatment regimen using drugs active against MRSA in infections of probable staphylococcal origin admitted to the hospital, especially if they have received antibiotic treatment in the last 3 months.

Effects on growth, weight and body composition after CFTR modulators in children with cystic fibrosis.

BACKGROUND: Cystic Fibrosis (CF) is associated with compromised nutrition status, which is responsible for morbidity and mortality along with lung function decline. This study was designed to examine changes in anthropometric markers and body composition parameters by bioelectrical impedance analysis after CFTR modulator (CFTRm) treatment. METHODS: We compared anthropometric parameters and body composition before and after 6 and 12 months of CFTRm treatment. Results are stratified into subgroups according to the modulator used with dual therapy with lumacaftor + ivacaftor or tezacaftor + ivacaftor (LUMA/TEZ + IVA) or triple therapy with elexacaftor + tezacaftor + ivacaftor (ELE + TEZ + IVA). Body composition data are available in patients treated with ELE + TEZ + IVA. RESULTS: Two hundred and thirty-four children (55.1% male) were recruited. The median age was 13.6 years (inter-quartile range [IQR] 10.7-16.1). We can observe a statistically significant increase in the weight Z score and BMI Z score after CFTRm. In terms of changes in body composition, we observe a significant increase in fat mass (FM) expressed both in kilograms and as a percentage at 6 months (p < .05; Wilcoxon-test), with no such differences found at 12 months. We also observe a statistically significant increase in fat-free-mass (FFM), expressed in kilograms at 6 and 12 months (p < .05; Wilcoxon-test). CONCLUSION: Weight status improved and changes in body composition occurred in children after CFTRm therapy, including an increase of fat mass. Further studies are needed to confirm these changes in body composition and their impact on disease progression.

Ultrasound diagnosis of Terson syndrome as an indicator of extreme severity in neurocritical care patients.

INTRODUCTION: Terson syndrome (TS) is defined as any intraocular haemorrhage identified in patients with acute intracranial pathology. TS appears to be associated with clinical severity in patients with subarachnoid haemorrhage (SAH), but the association is yet to be defined in patients with traumatic brain injury (TBI) and intracerebral haemorrhage (ICH). This study aimed to evaluate the diagnostic performance of ocular ultrasound (OU) and its usefulness in clinical practice. MATERIAL AND METHODS: We performed an observational, prospective, single-centre study of neurocritical care patients. We analysed cases and controls, defined according to indirect ophthalmoscopy (IO) and OU findings. We determined the diagnostic characteristics of OU. A multivariate analysis was performed to identify clinically relevant associations. RESULTS: The sample included 91 patients diagnosed with ICH (41.76%), SAH (29.67%), and TBI (28.57%). TS was identified by OU in 8 patients (8.79%) and by IO in 24 (24.37%). The adjusted mortality rate in patients with TS showed an odds ratio (OR) of 4.15 (95% confidence interval [CI], 1.52-11.33). All patients with TS detected by OU presented Glasgow Coma Scale scores < 9, with an elevated risk of needing decompressive craniectomy (OR: 9.84; 95% CI, 1.64-59). OU presented an overall sensitivity of 30.43%, specificity of 98.53%, and diagnostic accuracy of 81.32%. For the detection of vitreous haemorrhage, sensitivity and specificity were 87.5% and 98.5%, respectively. CONCLUSIONS: OU diagnosis of TS identifies extremely critical patients, who may require the highest level of care; TS is an independent risk factor for in-hospital mortality.

Perioperative in Intensive Medicine of reconstructive surgery and burned patients. / Perioperatorio de cirugía plástica reconstructiva y quemados en Medicina Intensiva.

Burned patients may need prolonged admissions in the Intensive Care Service, both for initial care and for the pre and postoperative treatment of the multiple surgeries they require. The initial resuscitation of critically burned patients requires adequate monitoring to calculate the fluid therapy necessary to replenish the losses and ensure tissue perfusion, but without excesses that increase interstitial edema. In addition, monitoring can evaluate the systemic inflammatory response that can lead to shock and organic dysfunctions. After this initial phase we will find a critical patient who requires multiple reinterventions in non-optimal situations, so he will need special care over a long period of time. In addition, the Intensive Care Service offers specific postoperative care for reconstructive surgery and the transplantation of composite tissues (upper limb and face) in which its success depends on a rigorous control through adequate monitoring and treatment.

Ultrasound diagnosis of Terson syndrome as an indicator of extreme severity in neurocritical care patients. / El síndrome de Terson diagnosticado por ecografía como indicador de extrema gravedad en pacientes neurocríticos.

INTRODUCTION: Terson syndrome (TS) is defined as any intraocular haemorrhage identified in patients with acute intracranial pathology. TS appears to be associated with clinical severity in patients with subarachnoid haemorrhage (SAH), but the association is yet to be defined in patients with traumatic brain injury (TBI) and intracerebral haemorrhage (ICH). This study aimed to evaluate the diagnostic performance of ocular ultrasound (OU) and its usefulness in clinical practice. MATERIAL AND METHODS: We performed an observational, prospective, single-centre study of neurocritical care patients. We analysed cases and controls, defined according to indirect ophthalmoscopy (IO) and OU findings. We determined the diagnostic characteristics of OU. A multivariate analysis was performed to identify clinically relevant associations. RESULTS: The sample included 91 patients diagnosed with ICH (41.76%), SAH (29.67%), and TBI (28.57%). TS was identified by OU in 8 patients (8.79%) and by IO in 24 (24.37%). The adjusted mortality rate in patients with TS showed an odds ratio (OR) of 4.15 (95% confidence interval [CI], 1.52-11.33). All patients with TS detected by OU presented Glasgow Coma Scale scores < 9, with an elevated risk of needing decompressive craniectomy (OR: 9.84; 95% CI, 1.64-59). OU presented an overall sensitivity of 30.43%, specificity of 98.53%, and diagnostic accuracy of 81.32%. For the detection of vitreous haemorrhage, sensitivity and specificity were 87.5% and 98.5%, respectively. CONCLUSIONS: OU diagnosis of TS identifies extremely critical patients, who may require the highest level of care; TS is an independent risk factor for in-hospital mortality.

[Infectious acute gastroenteritis in the emergency department of an urban hospital]. / Gastroenteritis aguda infecciosa en urgencias de un hospital urbano.

OBJECTIVES: To examine the etiology, clinical, analytical and evolutionary characteristics of gastroenteritis in the pediatric population in the Emergency Department of Dr. Peset University Hospital in Health Care Area 10 in Valencia, Spain, over a 1-year period (2005). PATIENTS AND METHODS: Children < 15 years of age with acute diarrhea were prospectively enrolled in the Emergency Department. Data were collected through information sheets. Their stools were examined for diarrheagenic bacteria and viruses (rotavirus and adenovirus). RESULTS: 794 episodes of gastroenteritis were recorded. The incidence of rotavirus was 22 %, adenovirus 8 %, Campylobacter jejuni 7 % and Salmonella spp. 4 %. Socioeconomic characteristics were not helpful in differentiating disease due to specific enteropathogens. Ninety per cent cases caused by viruses only affected children under three years of age. Rotavirus gastroenteritis had a marked seasonal pattern (90 % cases in December-February). Among infants < or = 6 months of age rotavirus was less frequent as cause of diarrhea in breast-fed infants than in bottle-fed. Macroscopic blood in stools was reported almost exclusively among patients with a bacterial infection. In 96 % of all cases of diarrhea there was no dehydration, in 2 % it was mild, in 2 % moderate and none severe. Ten of the seventeen cases (59 %) of moderate dehydration were caused by rotavirus. Six percent of all children were hospitalised. CONCLUSIONS: Rotavirus was significantly more associated with the need for intravenous fluid therapy and hospitalisation than episodes negative for rotavirus. Rotavirus accounted for 3 % of hospitalisations in infants aged 1 month-2 years.

Mevalonic aciduria: report of two cases.

Mevalonic aciduria is a rare disease that is a consequence of a deficiency of mevalonate kinase, an inborn error in the biosynthesis of cholesterol. Approximately 30 cases have been reported. We present our data on two siblings with mevalonic aciduria as a contribution to the recognition of this subject. Both were born after uneventful pregnancies. Their parents were healthy and not consanguineous. They had normal somatic and psychomotor development until they were around 2 years old. After the second year of life they developed mental retardation, ataxia and hypotonia. MRI showed cerebellar atrophy of both hemispheres and vermis. One sibling, from the age of 10 years onwards, suffered from complex partial seizures that were controlled with levetiracetam and lamotrigine. At 11 and 12 years of age, respectively, they were able to walk without help, but their gait was broad and ataxic. Their speech was dysarthric, fine motor skills were impaired as result of cerebellar ataxia, and they had moderate mental retardation. Diagnosis of mevalonic aciduria was made at this age through urinary organic acid analysis by gas chromatography-mass spectroscopy, which revealed high urinary excretion of mevalonic acid. They are currently 18 and 17 years old, respectively, show mental retardation and are able to walk but with difficulty. In our patients, ataxia due to cerebellar atrophy and mental retardation have been the predominant clinical manifestations. In mildly affected patients who survive infancy, these seem to be the predominant findings.

[Nosocomial outbreak of epidemic keratoconjunctivitis in a neonatal intensive care unit]. / Brote nosocomial de queratoconjuntivitis epidémica en una unidad de cuidados intensivos neonatal.

OBJECTIVE: To describe an epidemic nosocomial outbreak of keratoconjunctivitis affecting at least 43 people in a Neonatal Intensive Care Unit in Madrid, between May and October 2002, perform epidemiologic research and determine preventive measures to prevent new outbreaks. METHODS: Description of the outbreak, clinical case definition, microbiologic and epidemiologic research through the use of questionnaires. Analysis of the incidence of subepithelial infiltrates 1 year after infection and the use of topical corticosteroid therapy. RESULTS: The epidemic began in the Neonatal Service, with a pair of twins being found as the initial focus. Dissemination occurred to about 24 workers of the unit, and 19 workers from other services. The microbiologic diagnosis confirmed adenovirus in 10 conjunctival smears and one serologically, with the remainder obeying clinical and epidemiological criteria of such infection. Infected patients using topical corticosteroids had a higher incidence of infiltrates 12 months later than those not using such agents (p=0.003 in Fisher test). CONCLUSIONS: Epidemic keratoconjunctivitis occurs frequently, is highly contagious and has possible long-term sequelae, necessitating the use of preventive measures to avoid spread and new outbreaks.

Determinación de Helicobacter spp. en mucosa gástrica glandular de muías a través de la prueba de la actividad de la ureasa e histopatología / Determination of Helicobacter spp. in glandular gastric mucosa of mules through the test of urease activity and histopathology

RESUMEN La información sobre la presentación y los factores predisponentes del síndrome de úlcera gástrica en mulas (SUGM) es escasa en comparación con el síndrome de úlcera gástrica en equinos (SUGE) y asnales. Debido a la naturaleza multifactorial de este síndrome, la helicobacteriosis ha sido estudiada en otras especies. El objetivo de este trabajo fue establecer la presencia de Helicobacter spp. en mucosa gástrica de mulas a través de la prueba rápida de la ureasa (PRU) y de análisis histopatológico. Menos del 27% de las muestras reaccionaron a la PRU, con tiempos prolongados de reacción, y al Agar Urea (prueba de oro), con menor porcentaje de positividad. La histopatología reveló procesos inflamatorios crónicos, sin presencia de bacterias curvoespiraladas. Las PRU no fueron conclusivas en la determinación de Helicobacter spp., comportamiento similar reportado en equinos. Se requieren exámenes diagnósticos más específicos y procedimientos complementarios orientados a explorar por regiones del estómago en la consideración del número de muestras representativas.

ABSTRACT Information on the presentation and predisposing factors of Mule Gastric Ulcer Syndrome (MGUS) is scarce, compared to Equine Gastric Ulcer Syndrome (EGUS) and donkeys. Within the multifactorial nature of this syndrome, helicobacteriosis has been studied in other species. The objective of this work was to establish the presence of Helicobacter spp. in gastric mucosa of mules, through the rapid urease test (RUT) and histopathological analysis. Less than 27% of the samples reacted to RUTs, with prolonged reaction times, and Urea Agar (gold test), with a lower percentage of positivity. Histopathology revealed chronic inflammatory processes, without the presence of curved-spiral bacteria. The RUTs were not conclusive in the determination of Helicobacter spp., a similar behavior reported in horses. More specific diagnostic tests and complementary procedures are required to explore the regions of the stomach in consideration of the number of representative samples.

Anatomical and functional connectivity of the transected ulnar nerve after accessory nerve neurotization in the cat.

AIM: The objective of this experimental study was to test the capacity of accessory nerve motoneurons to innervate muscles of the ulnar nerve territory after direct anastomosis. METHODS: This study used 22 cats in two groups: experimental group (15 cats) and control group (7 cats). The first one was followed during twelve months using electromyographic records every two months postsurgery; muscle and nerve histological assessment and counting horseradish peroxidase-labeled motoneurons. RESULTS: Our results showed that reinnervation was achieved in 12/15 nerves. The number of HRP labelled medullar motoneurons after anastomosis showed a significant statistic difference with a simple ulnar nerve transection; there was no significant statistic difference in labelling between the group with an anastomosis and the one with a simple accessory nerve transection. CONCLUSIONS: Direct anastomosis between the spinal accessory nerve and the ulnar nerve is achievable and thus, the accessory spinal nerve is another possible choice for correcting the motor deficit arising from lower brachial plexus avulsion, but the limited number of motoneurons would only allow partial reinnervation..

[Tuberculosis in the area of Lorca: to adapt or resist]. / Tuberculosis en la comarca de Lorca: adaptarse o resistir.

OBJECTIVE: We studied the epidemiological characteristic of tuberculosis in Lorca area, drug resistant and the effect of the immigration population (Ecuador) in this area. PATIENTS AND METHODS: A retrospective study for six years ago (1999, January to 2004, December) was realized. Epidemiological data, initial diagnostic probability, mycobacteria stain and cultive, drug resistance, treatment response, and epidemiological differences between immigrants and spain population were compared. RESULTS: Within 158 cases registered, 41.7 percent were immigrants with less than one year in Spain, the most part Ecuador population. We observed that extrapulmonar tuberculosis was lower initial diagnostic probability than pleural disease as well too haemoptisis, pleural pain and weight loss. It was identified positive micobacterial stain in 35.4 percent of respiratory samples. It was successfully results in 74 percent of cases and 13.9 percent of patients were lost, this result was frequently registered in immigrants, The isoniazide resistant in patients with not previous treatment was 5.3 percent and it was 9.5 percent in immigrants and 10.8 percent in Ecuador population. CONCLUSION: It is necessary improve: the diagnostic of extrapulmonar tuberculosis and avoid loss patient by programs of capture and then the successfully treatments raise. The isoniazide resistant in this area suggest that we must use initial four drug than tree and this manner not raise the drug resistant in the area.

Acute kidney injury in critically burned patients resuscitated with a protocol that includes low doses of Hydroxyethyl Starch.

Acute kidney injury (AKI) is an important complication in burn patients. Recently, it has been recommended that hydroxyethyl starch (HES) be avoided in burn patients because it increases the incidence of AKI. Our purpose was to study incidence of AKI in critically ill burn patients resuscitated with Ringer's solution and supplements of HES. We conducted an observational study of 165 patients admitted to the critical care burn unit (with 30 ± 15% TBSA burned). The main outcome measures were incidence of AKI, contributions of colloids and crystalloids, various severity scores, comorbidities, complications and mortality. According to the RIFLE criteria, 10 (6.1%) patients presented with Risk, 11 (6.7%) presented with Injury and 11 (6.7%) presented with Failure. According to the AKIN criteria, 9.7% presented stage I, 3% stage II and 10.3% stage III. Replacement therapy (RRT) was performed in 15 patients (9.1%), but in 6 of them RRT was employed in the final stages of multi-organ failure. The incidence of AKI in severe burn patients is high according to the RIFLE or AKIN criteria and these patients experience more complications and higher mortality. Our study suggests that the use of HES in low doses in the burn resuscitation phase does not cause more AKI than resuscitation without HES, but further evaluation is required. Further studies should be conducted.

La souffrance rénale aiguë (SRA) est une complication sévère des patients brûlés. Il a récemment été recommandé d'éviter les HydroxyEthylAmidons (HEA) chez les patients brûlés en raison de l'augmentation de l'incidence des SRA. Le but de ce travail est d'évaluer l'incidence de la SRA chez des patients réanimés avec du Ringer Lactate et des HEA. Il s'agit d'une étude observationnelle conduite auprès de 165 patients admis en réanimation pour brûlés (surface 30 +/-15%). Les principaux paramètre recueillis étaient la SRA, les cristalloïdes et colloïdes utilisés, les scores de gravité, les comorbidités, les complications et la mortalité. Selon la classification de Rifle, 10 (6,1%) patients étaient dans le groupe à risque, 11 (6,7%) avaient une souffrance rénale et 11 (6,7%) une insuffisance rénale. Selon les critères AKIN, 9,7% des patients étaient au stade 1, 3% au stade 2 et 10,3% au stade 3. Une épuration extra-rénale a été nécessaire à 15 (9,1%) patients, 6 d'entre eux étant à un stade avancé de défaillance multiviscérale. Basée sur les scores Rifle comme AKIN, l'incidence de souffrance rénale est élevée chez les brûlés et ceux qui en souffrent ont une morbidité et une mortalité plus élevées. Toutefois, notre étude laisse à penser que les patients ayant reçu des HEA n'ont pas plus de souffrance rénale que ceux n'en ayant pas reçu, des études plus poussées restant nécessaires.

A potassium channel toxin from the secretion of the sea anemone Bunodosoma granulifera. Isolation, amino acid sequence and biological activity.

A peptide toxin affecting potassium channels was isolated from the sea anemone Bunodosoma granulifera. It facilitates acetylcholine release at avian neuromuscular junctions, competes with dendrotoxin I, a probe for voltage-dependent potassium channels, for binding to synaptosomal membranes of rat brain with a Ki of 0.7 nM and suppresses K+ currents in rat dorsal root ganglion neurones in culture. It represents a new structural type of potassium channel toxin with the sequence V1RCDWFKETA10CRHAKSLGNC20RTSQKYRANC30AKTLQCC37 (M(r) 4275, three disulfides).

Regulation of cytosolic free Ca2+ in cultured rat alveolar macrophages (NR8383).

Ca2+ mobilization in the rat alveolar macrophage cell line NR8383 was examined with the Ca2+-sensitive fluorescent probe Fura-2. ATP and norepinephrine elicited a 108 and 46% increase, respectively, in cytosolic free Ca2+ concentration ([Ca2+]i). Acetylcholine, nicotine, isoproterenol, substance P, and vasoactive intestinal polypeptide did not alter [Ca2+]i. Inositol 1,4,5-trisphosphate (IP3) formation was also activated by ATP. The carbohydrate-rich cell wall preparation, zymosan, induced a gradual [Ca2+]i, increase only in the presence of external Ca2+, but did not activate IP3 formation. This increase was abolished by laminarin and by removal of extracellular Ca2+, suggesting that the [Ca2+]i increase was activated by beta-glucan receptors and mediated by Ca2+ influx. This influx was significantly reduced by SKF96365, but not by nifedipine, (omega-conotoxin GVIA, (omega-agatoxin IVA, or flunarizine. These results suggest that release of intracellular Ca2+ in NR8383 cells is regulated by P2-purinoceptors and that zymosan causes Ca2+ influx via a receptor-operated pathway.

[Diagnostic value of head-shaking nystagmus in vestibular clinical evaluation]. / Utilidad del nistagmo de agitación cefálica en la exploración vestibular clínica básica.

OBJECTIVES: To determine the sensitivity and specificity of the head-shaking nystagmus test (HSN), the nystagmus elicited in response to a vigorous rotation of the head in the horizontal plane, in the study of patients with peripheral unilateral vestibular disease. PATIENTS AND METHODS: Retrospectively, we analyze the relationships between the HSN and the rest of the videonystagmographic tests on eighty-three patients with peripheral unilateral vestibular disease. RESULTS: Twenty-three patients showed a positive head-shaking nystagmus; twenty-one of them had unilateral caloric hypofunction and only two had a symmetric caloric test, but both of them showed some type of vestibular dysfunction on other videonystagmographic test. In our series, the HSN sensitivity for the existence of peripheral vestibular disease was 48.8%, while the specificity was 95% in relation to the caloric test, reaching 100% when the gold standard was the presence of any abnormal videonystagmographic test. CONCLUSION: HSN is a simple test that can be useful to identify patients having unilateral vestibular hypofunction.

Characterization and localization of two forms of active Ca2+ transport in vesicles derived from rat submandibular glands.

Energy-dependent Ca2+ uptake was characterized in vesicles derived from rat submandibular salivary glands. Ca2+ transport was stimulated by submicromolar levels of Ca2+, reached a plateau at 1-20 microM Ca2+ then again increased as the Ca2+ concentration rose to millimolar levels. Ruthenium red (2.5 microM) was used to resolve this pattern of uptake into two components: ruthenium red-insensitive Ca2+ transport occurs in the presence of the dye, is stimulated by submicromolar Ca2+ concentrations and reaches a maximum steady state at about 1 microM Ca2+. The distribution of ruthenium red-insensitive Ca2+ uptake in membrane subfractions obtained by differential centrifugation is positively (r = 0.717) and significantly (p = 0.001) correlated with the distribution of membrane-bound RNA in the same subfractions. Ca2+ uptake which is abolished by ruthenium red is greatest at millimolar Ca2+ concentrations. Its distribution is positively (r = 0.828) and significantly (p = 0.0001) correlated with the cytochrome-c oxidase activity of the membrane subfractions but is unrelated to the distribution of particulate RNA and is negatively correlated with Na+-K+ ATPase activity. We conclude that vesicles derived from the endoplasmic reticulum of rat submandibular glands actively transport Ca2+ by a ruthenium red-insensitive mechanism which is stimulated at Ca2+ concentrations typical of the cytosol. Membranes derived from mitochondria also sequester Ca2+ but by a mechanism which is inhibited by ruthenium red and which reaches its maximum steady state capacity at relatively high Ca2+ concentrations.

Differential effects of chronic reserpine exposure on Ca2+ sequestering mechanisms in rat submandibular gland vesicles.

To determine the effects of exposure to reserpine on subcellular Ca2+ transporting systems, active Ca2+ uptake was measured with and without ruthenium red in submandibular gland vesicles obtained from rats after chronic treatment with reserpine. The properties of ruthenium red-sensitive Ca2+ uptake were similar to those measured in submandibular gland vesicles from untreated rats: it was abolished by the dye, was relatively low at 1 microM Ca2+ but increased markedly at millimolar Ca2+ levels and was positively and significantly correlated with the mitochondrial membrane marker, cytochrome-C oxidase activity, in membrane subfractions obtained by differential centrifugation (r = 0.67, p = 0.0005, n = 29). On the other hand, ruthenium red-insensitive Ca2+ uptake, though stimulated at submicromolar Ca2+ concentrations, was reduced by a mean of 54% compared to preparations from untreated animals and particulate RNA content was 18% of that found in control preparations. Moreover, the distributions of ruthenium red-insensitive Ca2+ uptake and particulate RNA (which are closely correlated in vesicles from untreated rats) were not significantly related when measured in vesicles of submandibular glands from reserpine treated rats. Other membrane markers and overall membrane protein content were not significantly altered after chronic reserpine exposure. We conclude that reserpine treatment has little effect on mitochondrial Ca2+ uptake capacity but abolishes or drastically reduces the high affinity Ca2+-sequestering activity which, in submandibular gland vesicles from untreated rats, is apparently associated with the endoplasmic reticulum.

Amiloride inhibits 22Na uptake and [3H]QNB binding in rat submandibular cells.

Dispersed acini isolated by collagenase digestion of the rat submandibular gland were used to compare the effects of amiloride and furosemide on the uptake of the isotopic tracer 22Na and on the binding of [3H]quinuclidinyl benzylate ([3H]QNB). In mM concentrations, both inhibitors reduced 22Na uptake in resting cells 34 and 25-29%, respectively. Acetylcholine (1 microM) enhanced uptake 23% and this effect was reduced 45% by amiloride and 26% by furosemide. Amiloride inhibited the binding of [3H]QNB to crude membranes prepared from fresh submandibular glands in a dose-dependent fashion (IC50 = 8 x 10(-6) M). Furosemide (3 x 10(-8) to 10(-3) M) did not inhibit radioligand binding. Na influx into resting salivary acini thus appears to occur by both amiloride-sensitive and furosemide-sensitive transport systems. The similar inhibition by furosemide of unstimulated and stimulated uptake of 22Na suggests that acetylcholine does not significantly activate the cotransport system within the time frame (i.e., 2 min) of the experiments. Acetylcholine appears to activate an amiloride-sensitive Na/H antiport, but amiloride blocks cholinergic receptors and may thus affect Na transport by receptor blockade. Other actions of amiloride, such as its ability to penetrate into cells and to act as a weak base which alters intracellular pH, may also contribute to the inhibition of Na entry into salivary cells.