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1.
Med Intensiva (Engl Ed) ; 46(2): 72-80, 2022 02.
Article in English | MEDLINE | ID: mdl-35115112

ABSTRACT

OBJECTIVE: To compare the safety and effectiveness of Continuous Positive Airway Pressure (CPAP) vs. High Flow Nasal Cannula (HFNC) to prevent therapeutic failure and the need of invasive ventilation in children with acute moderate-severe bronchiolitis. DESIGN: A systematic review and meta-analysis. SETTING: Medline, Embase, Lilacs, Cochrane and gray literature (May 2020) was performed. PARTICIPANTS: Randomized clinical trials patients with moderate to severe bronchiolitis. MAIN VARIABLES: Therapeutic failure, need for invasive ventilation, adverse events, length of PCCU and of hospital stay. INTERVENTION: The quality of the studies was assessed with the Cochrane risk and bias tool. We conducted meta-analysis using fixed effect model and random effects model. RESULTS: Three RCTs were included. Showed less risk of therapeutic failure with CPAP compared with HFNC (RR=0.7; 95%CI 0.5-0.99) developed hours later in patients with CPAP (MD=3.16; 95%CI 1.55-4.77). We did not find differences in other outcomes, such as need of invasive ventilation (RR=0.60; 95%CI 0.25-1.43), apnea (RR=0.40; 95%CI 0.08-1.99), or number of days in the intensive care unit (MD=0.02; 95%CI -0.38 to 0.42), and length of hospitalization (MD=-1.00; 95%IC -2.66 to 0.66). Adverse events (skin lesions) were more common with CPAP (RR 2.47; 95%CI 1.17-5.22). CONCLUSIONS: In moderate/severe bronchiolitis CPAP demonstrated a lower risk of therapeutic failure and a longer time to failure. But more adverse events like nasal injury. There were no differences in other variables.


Subject(s)
Bronchiolitis , Cannula , Bronchiolitis/therapy , Child , Continuous Positive Airway Pressure , Humans , Length of Stay
2.
Med. intensiva (Madr., Ed. impr.) ; 46(2): 72-80, feb. 2022. ilus
Article in English | IBECS | ID: ibc-204179

ABSTRACT

Objective: To compare the safety and effectiveness of Continuous Positive Airway Pressure (CPAP) vs. High Flow Nasal Cannula (HFNC) to prevent therapeutic failure and the need of invasive ventilation in children with acute moderate-severe bronchiolitis.Design: A systematic review and meta-analysis.SettingMedline, Embase, Lilacs, Cochrane and gray literature (May 2020) was performed.ParticipantsRandomized clinical trials patients with moderate to severe bronchiolitis.Main variablesTherapeutic failure, need for invasive ventilation, adverse events, length of PCCU and of hospital stay.InterventionThe quality of the studies was assessed with the Cochrane risk and bias tool. We conducted meta-analysis using fixed effect model and random effects model.Results: Three RCTs were included. Showed less risk of therapeutic failure with CPAP compared with HFNC (RR=0.7; 95%CI 0.5–0.99) developed hours later in patients with CPAP (MD=3.16; 95%CI 1.55–4.77). We did not find differences in other outcomes, such as need of invasive ventilation (RR=0.60; 95%CI 0.25–1.43), apnea (RR=0.40; 95%CI 0.08–1.99), or number of days in the intensive care unit (MD=0.02; 95%CI −0.38 to 0.42), and length of hospitalization (MD=−1.00; 95%IC −2.66 to 0.66). Adverse events (skin lesions) were more common with CPAP (RR 2.47; 95%CI 1.17–5.22).Conclusion: sIn moderate/severe bronchiolitis CPAP demonstrated a lower risk of therapeutic failure and a longer time to failure. But more adverse events like nasal injury. There were no differences in other variables (AU)


Objetivo: Comparar la seguridad y la efectividad de la presión positiva continúa en la vía aérea (CPAP) y la cánula nasal de oxígeno de alto flujo (OAF) para prevenir el fracaso terapéutico y la necesidad de ventilación mecánica invasiva en niños con bronquiolitis aguda moderada y grave.Diseño: Revisión sistemática y metaanálisis.ÁmbitoBúsqueda en Medline, Embase, Lilacs, Cochrane y literatura gris (hasta mayo 2020).ParticipantesEnsayos clínicos aleatorizados en pacientes con bronquiolitis aguda moderada-grave.IntervencionesLa calidad de los estudios se evaluó utilizando la escala de riesgo de sesgos de Cochrane y se realizó un metaanálisis usando modelo de efectos fijos y de efectos aleatorios.VariablesFracaso terapéutico, necesidad de ventilación invasiva, eventos adversos, estancia en la UCIP y en hospitalización.Resultados: Tres estudios fueron incluidos. Evidenciamos menor riesgo de fracaso terapéutico en los pacientes con CPAP comparados con CAF (RR: 0,7; IC 95%: 0,5-0,99), y este se desarrolló más tarde en los pacientes con CPAP (MD: 3,16; IC 95%: 1,55-4,77). No hubo diferencias en otras variables, como la necesidad de ventilación invasiva (RR: 0,60; IC 95%: 0,25-1,43), apnea (RR: 0,40; IC 95%: 0,08-1,99), estancia en la UCIP (MD: 0,02; IC 95%: −0,38-0,42) y en hospitalización (MD: −1,00; IC 95%: −2,66-0,66). Los eventos adversos (lesiones en piel) fueron más comunes en CPAP (RR: 2,47; IC 95%: 1,17-5,22).Conclusiones: En bronquiolitis moderada y grave el CPAP demostró menor riesgo de fracaso terapéutico y una aparición más tardía, pero más eventos adversos (lesiones en piel). No encontramos diferencias en otras variables (AU)


Subject(s)
Humans , Child , Continuous Positive Airway Pressure/methods , Bronchiolitis/therapy , Oxygen Inhalation Therapy/methods , Treatment Outcome , Severity of Illness Index
5.
Article in English, Spanish | MEDLINE | ID: mdl-33168328

ABSTRACT

OBJECTIVE: To compare the safety and effectiveness of Continuous Positive Airway Pressure (CPAP) vs. High Flow Nasal Cannula (HFNC) to prevent therapeutic failure and the need of invasive ventilation in children with acute moderate-severe bronchiolitis. DESIGN: A systematic review and meta-analysis. SETTING: Medline, Embase, Lilacs, Cochrane and gray literature (May 2020) was performed. PARTICIPANTS: Randomized clinical trials patients with moderate to severe bronchiolitis. MAIN VARIABLES: Therapeutic failure, need for invasive ventilation, adverse events, length of PCCU and of hospital stay. INTERVENTION: The quality of the studies was assessed with the Cochrane risk and bias tool. We conducted meta-analysis using fixed effect model and random effects model. RESULTS: Three RCTs were included. Showed less risk of therapeutic failure with CPAP compared with HFNC (RR=0.7; 95%CI 0.5-0.99) developed hours later in patients with CPAP (MD=3.16; 95%CI 1.55-4.77). We did not find differences in other outcomes, such as need of invasive ventilation (RR=0.60; 95%CI 0.25-1.43), apnea (RR=0.40; 95%CI 0.08-1.99), or number of days in the intensive care unit (MD=0.02; 95%CI -0.38 to 0.42), and length of hospitalization (MD=-1.00; 95%IC -2.66 to 0.66). Adverse events (skin lesions) were more common with CPAP (RR 2.47; 95%CI 1.17-5.22). CONCLUSIONS: In moderate/severe bronchiolitis CPAP demonstrated a lower risk of therapeutic failure and a longer time to failure. But more adverse events like nasal injury. There were no differences in other variables.

6.
Brain Imaging Behav ; 11(4): 1037-1049, 2017 08.
Article in English | MEDLINE | ID: mdl-27473167

ABSTRACT

Reward may modulate the cognitive processes required for goal achievement, while individual differences in personality may affect reward modulation. Our aim was to test how different monetary reward magnitudes modulate brain activation and performance during goal-directed behavior, and whether individual differences in reward sensitivity affect this modulation. For this purpose, we scanned 37 subjects with a parametric design in which we varied the magnitude of monetary rewards (€0, €0.01, €0.5, €1 or €1.5) in a blocked fashion while participants performed an interference counting-Stroop condition. The results showed that the brain activity of left dorsolateral prefrontal cortex (DLPFC) and the striatum were modulated by increasing and decreasing reward magnitudes, respectively. Behavioral performance improved as the magnitude of monetary reward increased while comparing the non reward (€0) condition to any other reward condition, or the lower €0.01 to any other reward condition, and this improvement was related with individual differences in reward sensitivity. In conclusion, the locus of influence of monetary incentives overlaps the activity of the regions commonly involved in cognitive control.


Subject(s)
Brain/physiology , Executive Function/physiology , Goals , Reaction Time/physiology , Reward , Adult , Brain/diagnostic imaging , Brain Mapping , Female , Humans , Individuality , Magnetic Resonance Imaging , Male , Middle Aged , Neuropsychological Tests , Young Adult
7.
Arch Pediatr ; 23(7): 760-8, 2016 Jul.
Article in French | MEDLINE | ID: mdl-27266636

ABSTRACT

The diagnosis of primary immunodeficiency diseases (PIDs) is important for the early and adaptive care of patients and their families. Among the various known PIDs, a number of them concern the innate immune system, which involve a set of cells and mechanisms involved in the host defense by a nonspecific and fast response. The majority of patients with innate immunity defects have a predisposition to one isolated type of infection (bacterial, viral, or fungal), dependent on the genetic defect involved. This article describes the different PIDs involving innate immunity and the immunological investigations allowing for their diagnosis.


Subject(s)
Immunity, Innate , Immunologic Deficiency Syndromes/complications , Opportunistic Infections/etiology , Complement System Proteins/deficiency , Granulomatous Disease, Chronic/etiology , Humans , Mycobacterium Infections, Nontuberculous/immunology
10.
Brain Struct Funct ; 220(3): 1807-21, 2015.
Article in English | MEDLINE | ID: mdl-24696182

ABSTRACT

Existing evidence suggests that the presence of reward cues modifies the activity in attentional networks, however, the nature of these influences remains poorly understood. Here, we performed independent component analysis (ICA) in two fMRI datasets corresponding to two incentive delay tasks, which compared the response to reward (money and erotic pictures) and neutral cues, and yielded activations in the ventral striatum using a general linear model approach. Across both experiments, ICA revealed that both the right frontoparietal network and default mode network time courses were positively and negatively modulated by reward cues, respectively. Moreover, this dual neural response pattern was enhanced in individuals with strong reward sensitivity. Therefore, ICA may be a complementary tool to investigate the relevant role of attentional networks on reward processing, and to investigate reward sensitivity in normal and pathological populations.


Subject(s)
Brain/physiology , Cues , Individuality , Magnetic Resonance Imaging/methods , Nerve Net/physiology , Reward , Adult , Attention/physiology , Brain Mapping/methods , Frontal Lobe/physiology , Humans , Image Processing, Computer-Assisted , Male , Motivation/physiology , Parietal Lobe/physiology , Ventral Striatum/physiology , Young Adult
11.
Neuroimage ; 53(4): 1272-8, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20558314

ABSTRACT

Using two languages on an everyday basis appears to have a positive effect on general-purpose executive control in bilinguals. However, the neural correlates of this effect remain poorly understood. To investigate the brain bases of the bilingual advantage in executive control, we tested 21 Spanish monolinguals and 19 Spanish-Catalan early bilinguals in a non-verbal task-switching paradigm. As expected based on previous experiments on non-verbal task switching, we found activation in the right inferior frontal cortex and the anterior cingulate of monolingual participants. While bilingual participants showed a reduced switching cost, they activated the left inferior frontal cortex and the left striatum, a pattern of activation consistent with networks thought to underlie language control. Overall, these results support the hypothesis that bilinguals' early training in switching back and forth between their languages leads to the recruitment of brain regions involved in language control when performing non-linguistic cognitive tasks.


Subject(s)
Attention/physiology , Brain Mapping , Brain/physiology , Cognition/physiology , Multilingualism , Female , Humans , Image Interpretation, Computer-Assisted , Language , Male , Young Adult
12.
Braz. j. phys. ther. (Impr.) ; 9(3): 319-325, set.-dez. 2005.
Article in Portuguese | LILACS | ID: lil-432253

ABSTRACT

O presente estudo teve por finalidade verificar a presenca ou nao de correlacoes existentes entre a cifolordometria e o metodo Cobb, exame radiografico, avaliando a sua validade e confiabilidade, estabelecendo criterios para avliar a curva toracica por meio de cifolordometro. Metodo: para avaliar a convexidade toracica foram utilizados dois metodos distintos: o exame radiografico e a avaliacao realizada no cifolordometro. Foram submetidos 30 pacientes com idade media de 39+-15,8 anos a uma radiografia da coluna toracica, incidencia perfil, e posteriormente a mesma curva foi mensurada no cifolordometro. A avaliacao da curva toracica no cifolordometro constou de tres medidas sucessivas, realizadas com o objetivo de verificar a validade intra-observatoria desse metodo. Resultados: Observou-se que ha correlacao positiva r significativa entre os dois metodos abordados (rs>0,72 e p<0,000). tambem foi estabelecida uma metodologia clara e de facil reproducao para avaliar a curva toracica no cifolordometro, e por meio da analise das tres medidas realizadas em cada elemento da amostra foi confirmada a confiabilidade intra-observada (p>0,02) do metodo em discussao. Conclusao: Os resultados deste estudo mostram que o cifolordometro e um metodo confiavel, de facil acesso, alta reproducao e de muita eficacia na mensuracao da curva toracica


Subject(s)
Kyphosis , Radiography, Thoracic , Reproducibility of Results
13.
J Androl ; 21(3): 452-63, 2000.
Article in English | MEDLINE | ID: mdl-10819454

ABSTRACT

The uptake of amino acids by the isolated rat testis perfused with Krebs-Ringer solution with albumin has been studied using the single-passage, multiple-tracer technique with [14C]-mannitol as the reference tracer. When the perfusate contained no added amino acids, the uptake of [3H]-Leu was between 60% and 80% of the uptake of mannitol at all times after injection of the bolus; there was a small but significant uptake of some other amino acids studied (Ala, Gly, Glu, and Asp); and with Ala, Glu, and Asp, uptake increased slightly in increasing times after injection. There was no significant uptake of Arg. The uptake of Leu could be decreased by the inclusion of nonradioactive Leu in the perfusate, and the Km and Vmax of the transport were 0.067 mM and 19.5 nmole/(g x min), respectively. The Km value is similar to that for transport into brain and much less than the values obtained in other tissues for the related amino acid Phe, which is transported by the same L system. The transport of L-Leu in the testis was also inhibited by L-Phe or D-Phe, D-Leu, and by the synthetic amino acid Bch, the characteristic marker for the L system, but was only slightly reduced if the perfusate was free of sodium, as is expected for the L system. By autoradiography after fixation by perfusing with glutaraldehyde, the transport of Leu could be localized to the endothelial cells of the larger vessels of the testicular microvasculature.


Subject(s)
Endothelium/metabolism , Leucine/pharmacokinetics , Testis/metabolism , Alanine/pharmacokinetics , Animals , Arginine/pharmacokinetics , Aspartic Acid/pharmacokinetics , Autoradiography , Biological Transport/physiology , Glutamine/pharmacokinetics , Glycine/pharmacokinetics , In Vitro Techniques , Isotonic Solutions , Lysine/pharmacokinetics , Male , Perfusion , Phenylalanine/pharmacokinetics , Rats , Tritium
14.
J Androl ; 21(3): 444-51, 2000.
Article in English | MEDLINE | ID: mdl-10819453

ABSTRACT

The permeability-surface area products (PS) for sodium, Cr-EDTA, and cyanocobalamine (CoB12) have been determined in isolated perfused rat testes, using the single-passage multiple tracer technique, with albumin as the reference tracer. The validity of using albumin was established from its recovery in the perfusate leaving the testis, which was 98.73+/-0.48% of that for Cr-labeled red cells. The PS values obtained for Na, Cr-EDTA, and CoB12 were correlated with perfusate flow, both below and above levels that were equivalent to normal rates of blood flow in the testis (0.3 mL/[g x min]). The values found at the highest flow rates obtained (between 2.7 and 3.5 mL/[g x min]) were 2230+/-240 microL/(g x min) (n = 8) for sodium, 1460+/-140 microL/(g x min) (n = 7) for Cr-EDTA, and 850+/-80 microL/(g x min) (n = 7) for CoB12. These values are similar to those reported at equivalent flow rates for heart muscle and greater than those reported for skeletal muscle, both of which have unfenestrated capillaries similar to testis, but are less than the values for pancreas and salivary gland, which have fenestrated capillaries and are similar to most other endocrine tissues. However, the permeability coefficients for these markers in the testis (calculated using published values for the surface area of the testicular microvasculature) appear to be considerably greater than for any other tissue studied thus far. By extrapolating extraction values, either linearly or logarithmically, to obtain maximal values for PS for Cr-EDTA and CoB12, and comparing the ratio of these PS area values with the ratio of the diffusion coefficients of these molecules, it can be calculated that the equivalent pore radius for the testicular endothelium is between 5 and 6 nm, comparable to those calculated for other nonfenestrated endothelia.


Subject(s)
Capillary Permeability/physiology , Chelating Agents/pharmacokinetics , Edetic Acid/pharmacokinetics , Sodium/pharmacokinetics , Testis/blood supply , Albumins/pharmacokinetics , Animals , Chelating Agents/chemistry , Edetic Acid/chemistry , In Vitro Techniques , Indicator Dilution Techniques , Male , Molecular Weight , Perfusion , Rats , Rats, Wistar , Sodium/chemistry , Vitamin B 12/chemistry , Vitamin B 12/pharmacokinetics , Water
15.
J Membr Biol ; 119(2): 151-61, 1991 Jan.
Article in English | MEDLINE | ID: mdl-1904498

ABSTRACT

The nucleoside transport activity of human placental syncytiotrophoblast brush-border and basal membrane vesicles was compared. Adenosine and uridine were taken up into an osmotically active space. Adenosine was rapidly metabolized to inosine, metabolism was blocked by preincubating vesicles with 2'-deoxycoformycin, and subsequent adenosine uptake studies were performed in the presence of 2'-deoxycoformycin. Adenosine influx by brush-border membrane vesicles was fitted to a two-component system consisting of a saturable system with apparent Michaelis-Menten kinetics (apparent Km approx. 150 microM) and a linear component. Adenosine uptake by the saturable system was blocked by nitrobenzylthioinosine (NBMPR), dilazep, dipyridamole and other nucleosides. Inhibition by NBMPR was associated with high-affinity binding of NBMPR to the brush-border membrane vesicles (apparent Kd 0.98 +/- 0.21 nM). Binding of NBMPR to these sites was blocked by adenosine, inosine, uridine, thymidine, dilazep and dipyridamole, and the respective apparent Ki values were 0.23 +/- 0.012, 0.36 +/- 0.035, 0.78 +/- 0.1, 0.70 +/- 0.12 (mM), and 0.12 and 4.2 +/- 1.4 (nM). In contrast, adenosine influx by basal membrane vesicles was low (less than 10% of the rate observed with brush-border membrane vesicles under similar conditions), and hence no quantitative studies of adenosine uptake could be performed with these vesicles. Nevertheless, high-affinity NBMPR binding sites were demonstrated in basal membrane vesicles with similar properties to those in brush-border membrane vesicles (apparent Kd 1.05 +/- 0.13 nM and apparent Ki values for adenosine, inosine, uridine, thymidine, dilazep and dipyridamole of 0.14 +/- 0.045, 0.54 +/- 0.046, 1.26 +/- 0.20, 1.09 +/- 0.18 mM and 0.14 and 3.7 +/- 0.5 nM, respectively). Exposure of both membrane vesicles to UV light in the presence of [3H]NBMPR resulted in covalent labeling of a membrane protein(s) with a broad apparent Mr on SDS gel electropherograms of 77,000-45,000, similar to that previously reported for many other tissues, including human erythrocytes. We conclude that the maternal (brush-border) and fetal (basal) surfaces of the human placental syncytiotrophoblast possess broad-specificity, facilitated-diffusion, NBMPR-sensitive nucleoside transporters.


Subject(s)
Adenosine/metabolism , Placenta/metabolism , Thioinosine/analogs & derivatives , Trophoblasts/metabolism , Affinity Labels , Basement Membrane/metabolism , Biological Transport, Active , Cell Membrane/metabolism , Glycoside Hydrolases/metabolism , Humans , In Vitro Techniques , Kinetics , Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase , Microvilli/metabolism , Nucleosides/metabolism , Osmosis , Placenta/ultrastructure , Thioinosine/metabolism
16.
Cell Biochem Funct ; 7(3): 173-8, 1989 Jul.
Article in English | MEDLINE | ID: mdl-2507194

ABSTRACT

Silybin dihemisuccinate produces a decrease in the ethanol metabolic rate of rats. This effect is ascribed to an inhibition of the microsomal ethanol oxidizing system (MEOS). Alcohol dehydrogenase activity, catalase activity and NADPH cytochrome c reductase activity are not affected by the flavonoid. It is proposed that the inhibition of MEOS by silybin dihemisuccinate is related to its antioxidant properties, acting as a scavenger of the free radicals involved in ethanol metabolism by this enzymatic system. This observation may have therapeutical implications because microsomal lipid peroxidation induced by hydroxyl free radicals has been related to the etiology of hepatic alcoholic disease.


Subject(s)
Ethanol/metabolism , Flavonoids/pharmacology , Microsomes, Liver/drug effects , Silymarin/pharmacology , Animals , Antioxidants , Ethanol/blood , Free Radicals , Male , Microsomes, Liver/enzymology , Microsomes, Liver/metabolism , NADH Dehydrogenase/metabolism , NADPH-Ferrihemoprotein Reductase/metabolism , Oxidation-Reduction , Rats , Rats, Inbred Strains , Silybin , Silymarin/analogs & derivatives
17.
Q J Exp Physiol ; 73(6): 1013-6, 1988 Nov.
Article in English | MEDLINE | ID: mdl-3237979

ABSTRACT

Sulphate transport into and out of membrane vesicles prepared from both the brush-border and basal surfaces of the human placental trophoblast has been studied. For both surfaces of this epithelium clear evidence of trans-stimulation of influx is seen but for efflux, acceleration of labelled sulphate movement by addition of external sulphate is seen only in basal and not in brush-border membrane vesicles. This kinetic asymmetry may underlie the previously observed, but unexplained, finding that the concentration of sulphate is greater in the fetal than in the maternal circulation.


Subject(s)
Placenta/metabolism , Sulfates/metabolism , Biological Transport, Active , Epithelium/metabolism , Female , Humans , In Vitro Techniques , Kinetics , Maternal-Fetal Exchange , Microvilli/metabolism , Pregnancy , Trophoblasts/metabolism
18.
J Physiol ; 313: 65-79, 1981.
Article in English | MEDLINE | ID: mdl-7277237

ABSTRACT

1. Amino acid uptake was measured in resting cat submandibular glands with either a natural blood supply or perfused at constant flow with a Krebs-albumin solution. Following a bolus arterial injection of a 3H-labelled amino acid and D-[14C]mannitol (extracellular reference tracer), the venous effluent was immediately sampled sequentially. The maximal uptake, Umax, from the blood or perfusate was determined from the paired-tracer dilution curves using the expression: uptake % = (1 -- (3H/14C) X 100). 2. In glands with a natural blood supply, Umax values up to 46% were measured for short-chain (serine and alanine) and long-chain (valine, methionine, leucine, isoleucine, 1-amino-cyclopentane cyclopentane carboxylic acid, phenylalanine, tryptophan, tyrosine, histidine and glutamine) neutral amino acids. In contrast, Umax was negligible for amino acids of the imino-glycine group (proline and glycine) and the nonmetabolized amino acids, 2-aminoisobutyric acid (AIB) and methylaminoisobutyric acid (MeAIB). 3. In glands with a natural blood supply addition of an unlabelled amino acid to the tracer injectate reduced Umax for the test acid by up to 80%. The pattern of these interactions suggested the presence of two transport systems for neutral amino acids, one preferring short-chain and the other long-chain amino acids. 4. In glands perfused at constant flow rates with an amino acid-free Krebs-albumin solution high Umax values were measured: L-serine (66%), L-alanine (54%), L-leucine (43%), L-phenylalanine (42%) and L-tyrosine (51%). Only a low uptake was observed for L-proline (8%) and glycine (14%). There was no uptake of methylaminoisobutyric acid which confirms the result obtained in glands with an intact circulation. 5. Saturation of L-phenylalanine influx was observed in perfused glands as the perfusate concentration of unlabelled L-phenylalanine was increased from 0.5 to 20 mmol . 1-1. A Michaelis--Menten analysis based on a single entry system indicated an apparent Km of 6.4 +/- 0.8 mmol . 1-1 and a Vmax of 1719 +/- 94 nmol . min-1g.-1 6. Since the fenestrated capillaries in the salivary gland are readily permeable to the test amino acid and D-mannitol, it is most probable that the amino acid carriers are located in the basolateral side of the epithelium. 7. The use of a paired-tracer dilution technique to measure uptake in a single circulatory passage has enabled a detailed characterization of neutral amino acid transport in the salivary gland and has overcome the limitation of previous studies based on solute transfer from blood to saliva.


Subject(s)
Amino Acids/metabolism , Submandibular Gland/metabolism , Animals , Biological Transport , Cats , Epithelium/metabolism , Female , Kinetics , Male , Phenylalanine/metabolism , Submandibular Gland/blood supply
20.
J Neural Transm Suppl ; (15): 15-27, 1979.
Article in English | MEDLINE | ID: mdl-290752

ABSTRACT

Amino acid tmransport at the luminal side of brain capillary endothelium and the basal side of salivary epithelium were compared using a nondestructive, first-circulation, paired-tracer dilution method. In the brain, the reference molecule was an intravascular marker (Crone's method) whereas inthe salivary gland the reference was an extracellular marker of similar size to the test molecule. The unidirectional flux was related to a maximal uptake, U: U = 1 --test concentration/reference concentration Uptake and cross-inhibition experiments in brain suggest the presence of only a long-chain neutral L-amino acid transport system (leucine, phenyl-alanine, tryptophan, tyrosine, valine, methionine). In contrast, results in the salivary gland suggest 4 transport systems: 1. large neutral, 2. small neutral (alanine, serine), 3. basic (lysine) and 4. acidic (aspartic, glutamic). The same method was applied to localize binding sites. Ouabain bound very significantly to the salivary epithelium but not at all to the brain endothelium. The method described is of interest since it can be extended to any organ and possibly to man.


Subject(s)
Amino Acids/metabolism , Brain/metabolism , Ouabain/pharmacology , Salivary Glands/metabolism , Animals , Binding, Competitive , Biological Transport, Active/drug effects , Cats , Dogs , Epithelium/metabolism , Ouabain/metabolism
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