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1.
Diabet Med ; 29(2): 245-50, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21977945

RESUMO

INTRODUCTION: Metformin is a biguanide anti-hyperglycaemic drug. Metformin-associated lactic acidosis may sometimes be life-threatening. Continuous renal replacement therapy has been suggested as a method for resolving this extremely dangerous metabolic state. We describe the history of six patients admitted to the intensive care unit over a 28-month period in pre-shock conditions because of severe lactic acidosis, attributed to metformin-associated lactic acidosis, and successfully treated. METHODS: We reviewed the charts of six patients admitted to our intensive care unit between January 2008 and May 2010. After initial assessment, all patients were treated with continuous renal replacement therapy. Admission serum lactate and creatinine levels, pH, need for ventilatory and cardiovascular support, as well as continuous renal replacement therapy details and length of stay were reviewed. RESULTS: Admission pH levels of the six patients ranged between pH 6.63 and 7.0 and their serum lactate levels ranged between 12 and 27 mmol/l; the estimated creatinine clearance ranged between 6 and 24 ml min(-1) 1.73 m(-2) . All patients required vasoactive support and five required ventilatory support. Lactate levels decreased to near zero with continuous renal replacement therapy within 7-19 h in five of the patients whose intensive care unit length of stay ranged between 1 and 5 days. One patient's length of stay reached 11 days because of pneumonia, one died from multi-organ failure and another suffered permanent neurological damage following prolonged cardiopulmonary resuscitation before continuous renal replacement therapy was administered. All other patients recovered without sequellae. CONCLUSIONS: Accurate recognition of metformin-associated lactic acidosis and prompt initiation of haemodialysis are paramount steps towards rapid recovery. Large series reports and controlled studies may better determine the optimal duration and best dialysis technique in these patients.


Assuntos
Acidose Láctica/induzido quimicamente , Acidose Láctica/terapia , Injúria Renal Aguda/induzido quimicamente , Hipoglicemiantes/efeitos adversos , Metformina/efeitos adversos , Diálise Renal/métodos , Acidose Láctica/etiologia , Injúria Renal Aguda/sangue , Injúria Renal Aguda/complicações , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Creatinina/sangue , Feminino , Humanos , Hipoglicemiantes/administração & dosagem , Ácido Láctico/sangue , Masculino , Prontuários Médicos , Metformina/administração & dosagem , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
2.
Lab Chip ; 8(11): 1809-18, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18941679

RESUMO

We present a new lab-on-a-chip system for electrophysiological measurements on Xenopus oocytes. Xenopus oocytes are widely used host cells in the field of pharmacological studies and drug development. We developed a novel non-invasive technique using immobilized non-devitellinized cells that replaces the traditional "two-electrode voltage-clamp" (TEVC) method. In particular, rapid fluidic exchange was implemented on-chip to allow recording of fast kinetic events of exogenous ion channels expressed in the cell membrane. Reducing fluidic exchange times of extracellular reagent solutions is a great challenge with these large millimetre-sized cells. Fluidic switching is obtained by shifting the laminar flow interface in a perfusion channel under the cell by means of integrated poly-dimethylsiloxane (PDMS) microvalves. Reagent solution exchange times down to 20 ms have been achieved. An on-chip purging system allows to perform complex pharmacological protocols, making the system suitable for screening of ion channel ligand libraries. The performance of the integrated rapid fluidic exchange system was demonstrated by investigating the self-inhibition of human epithelial sodium channels (ENaC). Our results show that the response time of this ion channel to a specific reactant is about an order of magnitude faster than could be estimated with the traditional TEVC technique.


Assuntos
Canais Epiteliais de Sódio/metabolismo , Técnicas Analíticas Microfluídicas/métodos , Oócitos/metabolismo , Xenopus , Animais , Eletroquímica , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Canais Epiteliais de Sódio/genética , Feminino , Humanos , Cinética , Oócitos/citologia , Técnicas de Patch-Clamp , Perfusão , Sódio/metabolismo , Sódio/farmacologia , Canais de Sódio/metabolismo , Fatores de Tempo
3.
Eur Ann Otorhinolaryngol Head Neck Dis ; 135(1): 25-31, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29274768

RESUMO

OBJECTIVES: The impact of hearing loss and of auditory rehabilitation (hearing aid, cochlear implant) on quality of life is a crucial issue. Commonly used questionnaires to assess quality of life in these patients (Nijmegen, APHAB, GBI) are time-consuming, difficult for patients to fill out, and show poor sensitivity to small improvements or deterioration. The objective of the present study was to validate a dedicated quality of life scale for hearing-impaired adults with or without auditory rehabilitation. MATERIAL AND METHODS: ERSA (Évaluation du Retentissement de la Surdité chez l'Adulte: Evaluation of the Impact of Hearing Loss in Adults) is a self-administered questionnaire. It is divided into 4 domains, each comprising 5 questions graded from 1 to 10. The questions are simple, and formulated so patients will answer according to how they feel at the actual time of the session. Test-retest reliability was measured in 38 patients. Internal coherence and validity against the APHAB questionnaire as gold standard and in relation to hearing performance were measured in 122 patients at auditory assessment. Sensitivity to change in hearing was measured in 36 cochlear implant patients, before and 6 or 12 months after implantation. RESULTS: Test-retest reliability was very satisfactory (ρ=0.88). Internal coherence was good for all questions. External validity, comparing ERSA to APHAB scores in the same non-implanted hearing-impaired patients, was good (ρ=0.52). Additionally, ERSA scores correlated with hearing performance in adverse conditions (monosyllabic words: ρ=0.22; sentences in noise: ρ=0.19). In patients tested before and after cochlear implantation, improvement in hearing performance in silence and in noise correlated with an improvement in ERSA score (ρ=0.37 to 0.59, depending on the test), but not to GBI score. CONCLUSION: The ERSA questionnaire is easy and quick to use, reliable, and sensitive to change in hearing performance after cochlear implantation.


Assuntos
Implante Coclear/métodos , Implantes Cocleares , Perda Auditiva/reabilitação , Qualidade de Vida , Inquéritos e Questionários , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Percepção da Fala , Resultado do Tratamento
4.
Biosens Bioelectron ; 22(12): 3196-202, 2007 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-17416513

RESUMO

We propose a new non-invasive integrated microsystem for electrophysiological measurements on Xenopus laevis oocytes. Xenopus oocyte is a well-known expression system for various kinds of ion channels, that are potential tools in drug screening. In the traditional "Two Electrode Voltage Clamp" (TEVC) method, delicate micromanipulation is required to impale an oocyte with two microelectrodes. In our system, a non-invasive electrical access to the cytoplasm is provided by permeabilizing the cell membrane with an ionophore (e.g. nystatin). Unlike the classical patch-clamp or "macropatch" techniques, this method does not require removal of the vitelline membrane. Cell handling is significantly simplified, resulting in more robust recordings with increased throughput. Moreover, because only part of the oocyte surface is exposed to reagents, the required volume of reagent solutions could be reduced by an order of magnitude compared to the TEVC method. The fabrication process for this disposable microchip, based on poly-dimethylsiloxane (PDMS) molding and glass/PDMS bonding, is cost-efficient and simple. We tested this new microdevice by recording currents in oocytes expressing the human Epithelial Sodium Channel (hENaC) for membrane potentials between -100 and +50 mV. We recorded benzamil-sensitive currents with a large signal-to-noise ratio and we also obtained a benzamil concentration-inhibition curve displaying an inhibition constant IC(50) of about 50 nM, comparable to previously published values obtained with the TEVC technique.


Assuntos
Dispositivos Lab-On-A-Chip , Oócitos/fisiologia , Técnicas de Patch-Clamp/instrumentação , Amilorida/análogos & derivados , Amilorida/farmacologia , Animais , Dimetilpolisiloxanos/química , Relação Dose-Resposta a Droga , Eletrodos , Canais Epiteliais de Sódio/efeitos dos fármacos , Canais Epiteliais de Sódio/fisiologia , Feminino , Humanos , Potenciais da Membrana , Silicones/química , Xenopus
5.
Ann Otolaryngol Chir Cervicofac ; 124(3): 148-54, 2007 Jul.
Artigo em Francês | MEDLINE | ID: mdl-17320034

RESUMO

OBJECTIVES: To summarize the indications and evaluate the Auditory Brainstem Implant (ABI) performances in neurofibromatosis type 2 (NF2) and other otologics indications, as postmeningitis ossified cochlea. MATERIAL AND METHODS: Main and first indication of ABI is NF2. Emergent indications are bilateral total ossified cochlea, vestibular schwannoma with controlateral lesions, cochlear nerve aplasia or inner ear's malformations. The pre-operative evaluation includes clinical, radiological, lipreading, and psychological status. A translabyrinthine or retrosigmoid approach is performed, depending on tumoral or not tumoral status. The auditory perception with the ABI is evaluated by testing, the words recognition in open-set lists, and the speech understanding with usual sentences. RESULTS: In NF2 patients, best results are obtained in cases of smaller vestibular schwannoma and none, or short term, auditory deprivation. Negative prognostic factors are duration of total hearing loss (>10 years), tumor size (>30 mm), difficulties in electrode array placement, complications during post-operative course and number of active electrodes (<10). In cases of postmeningitis total deafness with totally ossified cochlea, results demonstrate a good benefit reaching these obtained with cochlear implant in post-meningitis deafness. CONCLUSION: These results show a clear benefit of ABI in NF2 patients, with or without previous tumor removal, in case of small tumor with a short duration of hearing loss. In case of postmeningitis ossified cochlea, results potentially reach those of cochlear implants.


Assuntos
Implantes Auditivos de Tronco Encefálico , Perda Auditiva Neurossensorial/cirurgia , Encéfalo/patologia , Calcinose/etiologia , Calcinose/patologia , Doenças Cocleares/etiologia , Doenças Cocleares/patologia , Nervo Coclear/patologia , Nervo Coclear/cirurgia , Eletrodos Implantados , Feminino , Perda Auditiva Neurossensorial/etiologia , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Neurofibromatose 2/complicações , Neuroma Acústico/complicações , Neuroma Acústico/patologia , Neuroma Acústico/cirurgia
6.
Ann Otolaryngol Chir Cervicofac ; 123(2): 71-8, 2006 Apr.
Artigo em Francês | MEDLINE | ID: mdl-16733469

RESUMO

OBJECTIVE: The aim of this study was to analyse performance of cochlear implants in a retrospective series of adults with postlingually in order to search for predictive factors and identify complications. METHODS: Between 1990 and 2003, 134 adult patients were implanted: 129 patients on one side and 5 patients on both sides. Hearing benefit at 6, 12, 24 and 36 months and performance at 12 months were analyzed as function of the etiology, age at implantation, lipreading and speech coding strategy. RESULTS: Compared to performances before implantation, cochlear implants provided significant and rapid improvement at 6 months (p<0.0001). The results were not correlated with age at implantation, etiology or lipreading ability before implantation. Performances were worse in patients with meningitis (p<0.01), but the percentage of improvement was similar between the different etiologies. Major complications were rare: one case of regressive postoperative facial nerve weakness. CONCLUSION: Cochlear implants provide significant and rapid improvement, with low morbidity. Results are not correlated with age at implantation, etiology or lipreading ability.


Assuntos
Implantes Cocleares/efeitos adversos , Adolescente , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo
7.
Mol Biochem Parasitol ; 100(1): 95-101, 1999 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10376997

RESUMO

Temperature and pH shifts trigger differential gene expression and stage transformation in Leishmania. The parasites encounter dramatic fluctuations in the extra-cellular pH between the mid-gut of the sand fly (pH>8) and the phagolysosomal vacuole of mammalian macrophages (pH<6). The authors examined the effect of pH shifts on heat shock gene expression in Leishmania amazonensis and Leishmania donovani promastigotes. Acidic pH resulted in preferential stability of the hsp83 transcripts at 26 degrees C, but hsp transcripts were not preferentially translated as observed during heat shock. Pre-conditioning of promastigotes to acidic pH did not alter the temperature threshold for hsp synthesis but lead to an increase in hsp synthesis mainly in L. donovani at 37 degrees C, and to a slight decrease in the arrest of tubulin synthesis in L. amazonensis. The stage specific morphological alterations that take place in vitro correlated with the arrest in tubulin synthesis and occurred at different temperatures in L. donovani and L. amazonensis.


Assuntos
Genes de Protozoários , Proteínas de Choque Térmico/genética , Leishmania/genética , Animais , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Choque Térmico HSP70/biossíntese , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico/biossíntese , Concentração de Íons de Hidrogênio , Leishmania/crescimento & desenvolvimento , Leishmania/metabolismo , Leishmania donovani/genética , Leishmania donovani/crescimento & desenvolvimento , Leishmania donovani/metabolismo , Proteínas de Protozoários/biossíntese , Proteínas de Protozoários/genética , Temperatura , Transcrição Gênica , Tubulina (Proteína)/biossíntese , Tubulina (Proteína)/genética
8.
Chest ; 120(2): 397-401, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11502635

RESUMO

STUDY OBJECTIVES: Nasal prongs (NPs), when used to assess nasal flow, can result in dramatic increases in nasal airflow resistance (NR). The aim of this study was to investigate whether the NP-induced increases in NR could be corrected by the simultaneous use of an internal nasal dilator (ND). DESIGN: NR was estimated by posterior rhinomanometry, in the basal state (NRb), and while breathing with NP (NRp), with ND (NRd), and with both ND and NP (NRd + p). PARTICIPANTS: The study was performed in 15 healthy subjects. MEASUREMENTS AND RESULTS: NR (mean NRb [+/- SEM], 2.5 +/- 0.4 cm H(2)O/L/s) significantly decreased with ND (NRd = 1.4 +/- 0.2 cm H(2)O/L/s; p < 0.001) and significantly increased with NP (NRp = 3.8 +/- 0.8 cm H(2)O/L/s; p < 0.001). A significant logarithmic relationship was found between NRd and NRb (r(2) = 0.95; p < 0.0001), and a significant exponential relationship was found between NRp and NRb (r(2) = 0.99; p < 0.0001). While breathing with both ND and NP, NRd + p was significantly lower than NRb (1.9 +/- 1.4 cm H(2)O/L/s; p < 0.02). CONCLUSIONS: Our results demonstrate that the ND tends to slightly overcorrect the NP-induced increase in NR and suggest that, in view of the possible effects of NPs on upper airway resistance, the combination of both devices might be used for nasal airflow monitoring during nocturnal polysomnography in patients presenting with highly resistive nares.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Nariz/fisiologia , Adulto , Feminino , Humanos , Masculino , Manometria/instrumentação , Pessoa de Meia-Idade , Polissonografia
9.
Chest ; 114(1): 166-70, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9674465

RESUMO

The goal of this study was to compare the effectiveness of three treatments aiming to reduce nasal airflow resistance (NR): an external nasal strip device (Respir+), an internal nasal mechanical dilator (Nozovent), and a topical decongestant (Pernazène). NR was estimated by active posterior rhinometry at both a 0.5 L/s flow (NRF) and a 1 cm H2O pressure (NRP), under four conditions: in the basal state, with Respir+, with Nozovent, and after treatment with Pernazène. The efficacy of each treatment was assessed by the percentage changes in NRF and NRP (%NRF and %NRP, respectively). The study was performed in 15 healthy subjects. The efficacy of the treatments was significantly different, depending on whether it was evaluated by NRF or by NRP (p<0.02), with %NRF and %NRP values, respectively, equal to the following: 88+/-20% and 91+/-14% with Respir+, 58+/-17% and 70+/-13% with Nozovent, and 55+/-29% and 69+/-22% with Pernazène. NRF remained unchanged with Respir+, whereas it significantly decreased with Nozovent and Pernazène (p<0.0001). No significant difference was observed between the effects of the two latter treatments. These results demonstrate that Nozovent, which involves no risk of side effects or drug interactions, is an effective treatment to improve nasal breathing. Nozovent might therefore be recommended as an alternative to topical decongestants, for certain subjects presenting with nasal obstruction.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Nariz/fisiologia , Administração Intranasal , Adolescente , Agonistas alfa-Adrenérgicos/administração & dosagem , Agonistas alfa-Adrenérgicos/farmacologia , Adulto , Resistência das Vias Respiratórias/efeitos dos fármacos , Dilatação , Interações Medicamentosas , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Descongestionantes Nasais/administração & dosagem , Descongestionantes Nasais/farmacologia , Obstrução Nasal/tratamento farmacológico , Obstrução Nasal/terapia , Nariz/efeitos dos fármacos , Pressão , Ventilação Pulmonar/efeitos dos fármacos , Ventilação Pulmonar/fisiologia , Reologia
10.
Chest ; 115(6): 1514-8, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10378542

RESUMO

The goal of this study was to compare the isolated and combined effects of two treatments being used to reduce nasal airflow resistance (NR): an internal nasal mechanical dilator (Nozovent; Prevancure; Sté Pouret, Paris, France) and a topical decongestant, fenoxazoline hydrochloride (Aturgyl; Synthelabo; Le Plessis-Robinson, France). The study was performed in 17 healthy subjects. NR was estimated by active posterior rhinometry at a 0.5 L/s flow under four conditions: in the basal state, with the internal nasal mechanical dilator, after treatment with fenoxazoline hydrochloride, and with both fenoxazoline hydrochloride and the mechanical dilator. The mean NR (+/- SD) decreased from 1.65+/-0.54 cm H2O/L/s in the basal state to 1.02+/-0.27 cm H2O/L/s with the mechanical dilator (p < 0.001), 1.03+/-0.47 cm H2O/L/s with fenoxazoline hydrochloride (p < 0.001), and 0.48+/-0.15 cm H2O/L/s with both the mechanical dilator and fenoxazoline hydrochloride (p < 0.001). The decreases in NR observed after using either the mechanical dilator (deltaNR(N)) or fenoxazoline hydrochloride (deltaNR(A)) were not significantly different. The decrease in NR observed with both (deltaNR(N + A)) was not significantly different from the sum deltaNR(N) + deltaNR(A): 1.16+/-0.53 cm H2O/L/s vs 1.25+/-0.63 cm H2O/L/s, respectively (p > 0.05). deltaNR(N + A) strongly correlated with deltaNR(N) + deltaNR(A): deltaNR(N + A) = 0.80 (deltaNR(N) + deltaNR(A)) + 0.15 (r = 0.96; p < 0.0001). However, the slope of the regression line of deltaNR(N + A) vs deltaNR(N) + deltaNR(A) was significantly lower than unity (p < 0.003). These results demonstrate that, although not totally additive, the effects of using the mechanical dilator and fenoxazoline hydrochloride are cumulative. Further studies that include patients with nasal obstruction would allow us to better evaluate the benefit of a therapy combining both treatments.


Assuntos
Imidazóis/administração & dosagem , Descongestionantes Nasais/administração & dosagem , Nariz/fisiologia , Administração Tópica , Adulto , Pressão do Ar , Resistência das Vias Respiratórias/efeitos dos fármacos , Resistência das Vias Respiratórias/fisiologia , Dilatação/instrumentação , Feminino , Humanos , Masculino , Obstrução Nasal/fisiopatologia , Obstrução Nasal/terapia , Nariz/efeitos dos fármacos , Valores de Referência
11.
Chest ; 118(2): 366-71, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10936126

RESUMO

STUDY OBJECTIVES: The aim of this study was to investigate whether nasal prongs, which have been proposed to assess nasal flow during sleep, affect nasal airflow resistance (NR). DESIGN: NR was estimated by posterior rhinomanometry at a 0.5 L/s flow, under eight conditions: in the basal state, and with seven different nasal prongs. PARTICIPANTS: The study was performed in 17 healthy supine subjects, 8 of whom had basal NR values within the normal range (< or = 2 cm H(2)O.L(-1).s, group 1), and 9 had increased basal NR values (> 2.5 cm H(2)O.L(-1).s, group 2), because of nare narrowness and/or deviated nasal septum. MEASUREMENTS AND RESULTS: NR increased significantly while breathing with nasal prongs (p < 0.0001 in both groups). The changes in NR (DeltaNR) induced by the different nasal prongs were characterized by large intersubject and intrasubject variability, with a maximum DeltaNR of 24.2 cm H(2)O.L(-1).s. Significant differences were found between the DeltaNR induced by the different nasal prongs (p < 0.001 in group 1, and p < 0.0003 in group 2), and for six of them, DeltaNR was significantly higher in group 1 than in group 2 (p < 0.02). CONCLUSIONS: This study demonstrates that nasal prongs can markedly increase NR in subjects presenting with nare narrowness and/or deviated nasal septum. Further investigations that would include nocturnal polysomnography are still required to evaluate the possible influence of nasal prongs on the diagnosis of obstructive sleep apnea syndrome and its severity.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Monitorização Fisiológica/instrumentação , Obstrução Nasal , Adulto , Diagnóstico Diferencial , Desenho de Equipamento , Feminino , Humanos , Masculino , Manometria , Pessoa de Meia-Idade , Obstrução Nasal/diagnóstico , Obstrução Nasal/fisiopatologia , Nariz , Polissonografia , Pressão , Valores de Referência , Síndromes da Apneia do Sono/diagnóstico , Síndromes da Apneia do Sono/fisiopatologia
12.
Intensive Care Med ; 23(2): 208-13, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9069008

RESUMO

OBJECTIVE: To assess the efficacy and reliability of neonatal high-frequency ventilators. DESIGN: Bench evaluation of neonatal high-frequency ventilators. SETTING: Physiology department and university hospital neonatal intensive care unit. INTERVENTIONS: HFV-Babylog 8000 (Dräger Medical), OHF 1 (Dufour), and SensorMedics 3100A (Sensor-Medics) ventilators were connected to a neonatal test-lung. Tidal volume, peak-to-peak pressure amplitude, and mean airway pressure were measured for several ventilator settings, endotracheal tube sizes, and lung compliances. MEASUREMENTS AND RESULTS: Increasing peak-to-peak pressure resulted in a linear increase in tidal volume delivery in the 0-30% range of maximum amplitude. No significant increase in tidal volume was observed with the HFV-Babylog 8000 when pressure amplitude was above 50%. The maximum tidal volume delivered was substantially smaller with the HFV-Babylog 8000 than with the OHF 1 or SensorMedics 3100A. Tidal volume increased with endotracheal tube size with all three ventilators. Increasing test-lung compliance resulted in lower tidal volumes only with OHF 1. Decreasing mean airway pressure was responsible for a decrease in tidal volume delivery with HFV-Baby-log 8000. CONCLUSION: We found that under our test conditions two of the three ventilators delivered adequate tidal volumes at the usual frequency of 15 Hz, regardless of the size of the endotracheal tube and of the mechanical properties of the respiratory system. When lung compliance increased or mean airway pressure decreased, both of which are common events during the recovery phase of hyaline membrane disease, we found that the intrinsic properties of two of the ventilators tested were responsible for a decrease in tidal volume. This decrease may account for some cases of heretofore unexplained hypercapnia.


Assuntos
Ventilação de Alta Frequência , Cuidados Críticos , Estudos de Avaliação como Assunto , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Modelos Biológicos , Volume de Ventilação Pulmonar
13.
J Appl Physiol (1985) ; 77(5): 2219-23, 1994 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7868437

RESUMO

It has been observed that sustained exercise results in a prolonged increase in alveolar epithelial permeability, as assessed by the pulmonary clearance rate of aerosolized 99mTc-labeled diethylenetriaminepentaacetate (Lorino et al. J. Appl. Physiol. 67: 2055-2059, 1989). The involvement of lipid peroxidation in this increased permeability was tested in seven nonsmoking volunteers by comparing the exercise-induced increases in pulmonary 99mTc-diethylenetriaminepentaacetate clearance before and after a 3-wk supplementation with oral vitamin E (1,000 IU/day), according to a protocol designed as a single-blind crossover study. The 60-min exercise was performed on a treadmill at a constant load corresponding to 80% of maximal O2 uptake. Administration of vitamin E, a very important antioxidant, did not reduce the exercise-induced increase in lung clearance, suggesting that the exercise-induced increase in lung epithelial permeability does not primarily result from the occurrence of lipid peroxidation in the alveolar membrane. This result thus corroborates the hypothesis of an alteration of the intercellular tight junctions due to the mechanical effects of hyperventilation.


Assuntos
Exercício Físico/fisiologia , Pulmão/efeitos dos fármacos , Vitamina E/farmacologia , Administração Oral , Adulto , Gasometria , Cromatografia Líquida de Alta Pressão , Humanos , Pulmão/diagnóstico por imagem , Pulmão/metabolismo , Masculino , Espectrometria de Massas , Permeabilidade , Cintilografia , Método Simples-Cego , Pentetato de Tecnécio Tc 99m/farmacocinética , Vitamina E/sangue
14.
J Appl Physiol (1985) ; 81(3): 1071-7, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8889736

RESUMO

Cigarette smoking increases the alveolar epithelial permeability to small solutes, as assessed by the pulmonary clearance of aerosolized 99mTc-labeled diethylenetriaminepentaacetate. The involvement of lipid peroxidation in this increased clearance was tested in eight asymptomatic young smokers by investigating the effects of a 3-wk supplementation with oral vitamin E (1,000 IU/day) on pulmonary clearance according to a protocol designed as a single-blind crossover study. Indexes of acute tobacco intoxication (exhaled CO, carboxyhemoglobin, and urinary cotinine) and lung function parameters [including Krogh factor (KCO)] were also studied. Under control conditions, pulmonary clearance was abnormally increased (2.93 +/- 0.78%/min), whereas KCO was in the normal range. Pulmonary clearance correlated strongly with expired CO (P < 0.04), HbCO (P < 0.005), urinary cotinine (P < 0.003), and KCO (P < 0.004). Supplementation with vitamin E, a highly efficient antioxidant, neither decreased the pulmonary clearance nor altered the above correlations. However, the strong correlations observed between pulmonary clearance and indexes of acute tobacco intoxication, which reflect the amount of inhaled smoke and the resultant oxidant stress, do not allow exclusion of the involvement of lipid peroxidation in the pulmonary clearance increase observed in smokers.


Assuntos
Pulmão/efeitos dos fármacos , Nicotina/toxicidade , Sistema Respiratório/efeitos dos fármacos , Fumar , Vitamina E/farmacologia , Adulto , Creatinina/urina , Feminino , Humanos , Masculino , Testes de Função Respiratória
15.
J Appl Physiol (1985) ; 87(2): 605-10, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10444619

RESUMO

This study was designed to determine the responses of lung volume and respiratory resistance (Rrs) to decreasing levels of continuous negative airway pressure (CNAP). Twenty normal subjects were studied in the basal state and under CNAP levels of -5, -10, and -15 hPa. Rrs was measured by the forced oscillation technique (4-32 Hz). End-expiratory lung volume (EELV) and tidal volume (VT) were measured by whole body plethysmography. Rrs was extrapolated to 0 Hz (R(0)) and estimated at 16 Hz (R(16)) by linear regression analysis of Rrs vs. frequency. Specific Rrs, SR(0) and SR(16), were then calculated as R(0) (EELV + VT/2) and R(16) (EELV + VT/2), respectively. EELV significantly decreased, whereas R(0), R(16), SR(0), and SR(16) significantly increased, as the CNAP level decreased (P < 0.0001 for all). At the lowest CNAP level, R(0) and R(16) reached 198 +/- 13 and 175 +/- 9% of their respective basal values. The CNAP-induced increase in R(0) was significantly higher than that in R(16) (P < 0.004). Our results demonstrate that the CNAP-induced increase in Rrs does not result from a direct lung volume effect only and strongly suggest the involvement of other factors affecting both intrathoracic and extrathoracic airway caliber.


Assuntos
Resistência das Vias Respiratórias/fisiologia , Ventilação Pulmonar/fisiologia , Volume de Ventilação Pulmonar/fisiologia , Adulto , Feminino , Volume Expiratório Forçado , Humanos , Medidas de Volume Pulmonar , Masculino , Pessoa de Meia-Idade , Pletismografia , Pressão , Análise de Regressão , Respiração Artificial
16.
Br J Ophthalmol ; 67(10): 688-92, 1983 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6412738

RESUMO

A clinical study of vernal keratoconjunctivitis in black children in Southern Africa was conducted to report on the peculiar, predominantly limbal form of the disease, and to test its response to therapy. Pigmented and thickened limbal conjunctiva gave the disease its typical appearance. In severe cases these lesions were encroaching on to the cornea and threatened sight. Placebo had no effect on the course of the disease. Topical steroids and sodium cromoglycate were equally effective. A combination of steroids and SCG proved particularly effective in treating severe cases, indicating a possible synergistic effect of the 2 drugs.


Assuntos
Ceratoconjuntivite/tratamento farmacológico , Adolescente , População Negra , Criança , Pré-Escolar , Cromolina Sódica/uso terapêutico , Dexametasona/uso terapêutico , Quimioterapia Combinada , Feminino , Humanos , Masculino , Estações do Ano , África do Sul
17.
Br J Ophthalmol ; 70(10): 737-41, 1986 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3778857

RESUMO

Labrador keratopathy (LK) is an acquired corneal degeneration thought to be caused by chronic exposure to solar irradiation. Reports so far suggest that it is a progressive or at least a stationary condition. There are no detailed reports on recommended therapy. A prospective clinical study was conducted to show regression of LK following extracapsular cataract extraction. Seventeen black patients (26 eyes) with LK and mature cataracts underwent extracapsular cataract extraction. The severity of the LK was recorded photographically pre- and postoperatively. The follow-up ranged from 6 to fifteen months. Twenty-four eyes (92%) showed regression of the LK. The reduction in exposure to ultraviolet light as a result of aphakic photophobia could be one of the factors which have led to the regression of the LK.


Assuntos
Extração de Catarata , Doenças da Córnea/etiologia , Raios Ultravioleta/efeitos adversos , Idoso , Córnea/patologia , Doenças da Córnea/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acuidade Visual
18.
J Neurosurg ; 95(6): 1028-33, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11765818

RESUMO

The auditory brainstem implant (ABI) is designed to restore useful auditory sensations in patients with neurofibromatosis Type 2 (NF2). The implantation is usually performed at the time of tumor removal in patients who do not undergo radiation treatment. The authors evaluated the performance of ABIs in three patients with NF2 in whom vestibular schwannoma continued to grow after radiation treatment. These three patients with NF2 received a 21-channel ABI; a translabyrinthine approach was used for both the tumor removal and the ABI placement. The interval between radiosurgery and the tumor removal plus device implantation ranged from 2 to 11 years. In all cases, the tumor was growing and the patients presented with total deafness. The mean number of active electrodes in these three patients was equivalent to the average results reported in other patients who received ABIs. The patients in this study used the ABI regularly for everyday life and obtained useful levels of environmental sound recognition. It is concluded that hearing function can be rehabilitated using ABIs in patients with NF2, even if radiosurgery fails to control the tumor growth.


Assuntos
Tronco Encefálico/cirurgia , Implantes Cocleares , Perda Auditiva Central/cirurgia , Neurofibromatose 2/cirurgia , Neuroma Acústico/cirurgia , Radiocirurgia , Adolescente , Feminino , Audição , Perda Auditiva Central/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Neurofibromatose 2/complicações , Neuroma Acústico/complicações , Recuperação de Função Fisiológica
19.
J Cataract Refract Surg ; 15(3): 339-42, 1989 May.
Artigo em Inglês | MEDLINE | ID: mdl-2732934

RESUMO

The relatively high incidence of complications of anterior chamber implants has encouraged ophthalmologists to implant in the posterior chamber, even in eyes without posterior capsules. A new surgical technique for implantation of posterior chamber lenses in the ciliary sulcus is described. Twenty posterior chamber lenses were implanted in eyes which had had intracapsular cataract extraction, with a follow-up ranging from three to 14 months (mean 7.4 months). Although no serious complications occurred in this small series, the safety and viability of this technique will be established with a longer follow-up.


Assuntos
Lentes Intraoculares , Adulto , Idoso , Extração de Catarata , Corpo Ciliar/cirurgia , Seguimentos , Humanos , Ácido Hialurônico/uso terapêutico , Cápsula do Cristalino/cirurgia , Pessoa de Meia-Idade
20.
J Cataract Refract Surg ; 17(1): 97-8, 1991 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2005567

RESUMO

Aspiration of the lens cortex and capsule polishing are two important aspects of modern extracapsular cataract surgery. In this report we describe simple but useful modifications to the widely used Simcoe irrigation/aspiration cannula. The modifications consist of enlarging the aspiration port diameter from 0.3 mm to 0.4 mm and altering the terminal segment of the cannula to a sandblasted capsule polisher. The 0.4 mm diameter aspiration port reduces the incidence of capsular entrapment and allows a more efficient aspiration of cortex of varying textures. The modifications eliminate the need for a separate capsule polishing instrument and allow simultaneous lens material aspiration and capsular cleanup. These modifications can be used for any irrigation/aspiration cannula whether manually or machine operated.


Assuntos
Extração de Catarata/instrumentação , Cateterismo/instrumentação , Drenagem , Desenho de Equipamento , Humanos , Irrigação Terapêutica
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