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Biomedical subjects

F Barbé

Publications and source records attributed to F Barbé.

At least 19 recordsLinked to original sources
PubMed2000

The effect of 677C-->T and 1298A-->C mutations on plasma homocysteine and 5,10-methylenetetrahydrofolate reductase activity in healthy subjects.

We have studied the effect of common mutations (677C-->T and 1298A-->C) of the methylenetetrahydrofolate reductase (MTHFR) gene in sixty-six healthy French subjects, aged 27-47 years. Serum folate, vitamin B12, and plasma total homocysteine were measured as well as the specific activity of MTHFR in lymphocytes. The frequency of subjects homozygous for the 677TT genotype was 18%, and that of those homozygous for the 1298CC genotype was 12.5%. The frequency of individuals heterozygous for both mutations was 23.5%. The 1298A-->C mutation was associated with decreased MTHFR specific activity in subjects with both 677CC and 677CT genotypes. This activity was 60% for the 677CC/1298AC genotype and 52% for the 677CC/1298CC genotype when compared with the MTHFR specific activity of the 677CC/1298AA genotype. Heterozygotes for both mutations (677CT/1298AC genotype) had 36% of the reference specific activity. Although homocysteine levels in 677TT and 1298CC genotype subjects were higher than for other genotypes, no significant differences were observed among different genotypes. This may be due to high serum folate level in our samples, and suggests that folate therapy may be useful to prevent hyperhomocysteinaemia in homozygous mutant subjects.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed2000

Long-term effects of CPAP on daytime functioning in patients with sleep apnoea syndrome.

Daytime sleepiness, impaired cognitive performance and dysphoric mood are often present in patients with obstructive sleep apnoea syndrome (SAS). This prospective controlled study evaluates the effects of treatment with continuous positive airway pressure (CPAP) during 1 yr on daytime functioning in a large group of patients with SAS. The authors studied 80 patients (mean+/-sem 49+/-1 yrs) with SAS with a mean apnoea-hypopnoea index of 60+/-2 h-1, and 80 healthy control subjects matched for sex and age (46+/-1 yrs.). Measurements were obtained at the beginning of the study and 12+/-1 months later, and included: daytime sleepiness (Epworth scale), depression and anxiety (Beck tests), vigilance (Steer-Clear) and reaction time (Psychometer Vigilance Test 192). Drug, coffee and alcohol intake, as well as the sleep schedule, were also recorded. Results showed that, before treatment, patients were more somnolent (p<0.001), anxious (p<0.01) and depressed (p<0.001) than control subjects. Also, they had a longer reaction time (p<0.05) and poorer vigilance (p<0.01). The use of CPAP improved significantly the levels of somnolence (p<0.0001) and vigilance (p<0.01), but failed to modify anxiety and depression. Reaction time changes were minor. Variables with a potential confounding effect did not change during the study. These results provide firm evidence to substantiate the use of continuous positive airway pressure in patients with sleep apnoea syndrome.

Analysis of Variance↗
PubMed1999

Exhaled nitric oxide in patients with sleep apnea.

Cardiovascular diseases are frequent in patients with obstructive sleep apnea syndrome (OSAS), but the mechanisms underlying this association are largely unknown. Nitric oxide (NO) is a key regulatory element of vascular physiology. The concentration of NO in the exhaled air ([NOexh]) appears to be reduced in patients with systemic and pulmonary hypertension. This study sought to investigate whether [NOexh] is abnormal in patients with OSAS, and to explore potential relationships between [NOexh] and the severity of OSAS. We measured [NOexh] in 24 patients with OSAS (apnea-hypopnea index (AHI), 55 +/- 4 hour-1) (x +/- SEM), and in 7 healthy volunteers in whom OSAS was excluded clinically. [NOexh] was measured on line by a chemiluminescence analyzer (Dasibi Environmental Corporation, Glendale, Calif). Seven patients with OSAS (29%) had a positive history of cardiovascular disease. Mean [NOexh] was 19.7 +/- 3.2 ppb in healthy subjects, and 22.2 +/- 3.0 ppb in patients with OSAS (p = ns). [Noexh] was not significantly different in those patients with or without cardiovascular disease. [NOexh] was not significantly related to the AHI, the body mass index, or the arterial O2 saturation at night. These results show that [NOexh] is not abnormal in patients with OSAS, and that it does not relate to the presence of cardiovascular disease or to any of various common indices of disease severity.

Adult↗
PubMed1999

[The results of the operation of a monitoring unit for home oxygen therapy].

OBJECTIVE: This study aims to a) analyze the prevalence of domiciliary oxygen therapy (DOT) in Mallorca, b) evaluate the cost effectiveness of the DOT monitoring unit, and c) determine the survival of patients with chronic obstructive pulmonary disease who are presently receiving DOT. METHOD: When the DOT unit was created in April 1994, the situation of all patients receiving DOT in Mallorca was assessed in a transversal study. Over the next three years, these patients were reassessed regularly and all new prescriptions were evaluated (longitudinal study). RESULTS: Before the unit began work, DOT was prescribed for 71 out of 100,000 inhabitants. DOT was withdrawn from 31% of patients assessed in the transversal study. By the end of the longitudinal study, DOT was being prescribed at a rate of 56 times per 10,000 inhabitants. The activities of the DOT unit brought about annual savings of approximately 38 million pesetas. The number of patients with liquid oxygen and concentrators increased such that the latter has become the main delivery system. The survival of COPD patients with DOT in this study seems to be longer than report. CONCLUSIONS: a) The prevalence of DOT use in Mallorca before the DOT unit began operating was too high. b) The cost effectiveness of DOT monitoring is positive because DOT use has been optimized and significant savings have ensued (= 38 millions pesetas/year). c) The survival of COPD patients receiving DOT at present appears better than that reported in the literature, possibly related to the greater efficacy of modern treatment.

Aged↗
PubMed1999

Oxygen therapy during exacerbations of chronic obstructive pulmonary disease.

Venturi masks (VMs) and nasal prongs (NPs) are widely used to treat acute respiratory failure (ARF) in chronic obstructive pulmonary disease (COPD). In this study, these devices were compared in terms of their potentiality to worsen respiratory acidosis and their capacity to maintain adequate (> 90%) arterial oxygenation (Sa,O2) through time (approximately 24 h). In a randomized cross-over study, 18 consecutive COPD patients who required hospitalization because of ARF were studied. After determining baseline arterial blood gas levels (on room air), patients were randomized to receive oxygen therapy through a VM or NPs at the lowest possible inspiratory oxygen fraction that resulted in an initial Sa,O2 of > or = 90%. Arterial blood gas levels were measured again 30 min later (on O2), and Sa,O2 recorded using a computer during the subsequent approximately 24 h. Patients were then crossed-over to receive O2 therapy by means of the alternative device (NPs or VM), and the same measurements obtained again in the same order. It was observed that both the VM and NPs improved arterial oxygen tension (p<0.0001) to the same extent (p=NS), without any significant effect upon arterial carbon dioxide tension or pH. However, despite this adequate initial oxygenation, Sa,O2 was < 90% for 3.7+/-3.8 h using the VM and for 5.4+/-5.9 h using NPs (p<0.05). Regression analysis showed that the degree of arterial hypoxaemia (p<0.05) and arterial hypercapnia (p<0.05) present before starting O2 therapy and, particularly, the initial Sa,O2 achieved after initiation of O2 therapy (p<0.0001) enabled the time (in h) that patients would be poorly oxygenated (Sa,O2 < 90%) on follow-up to be predicted. These findings suggest that, in order to maintain an adequate (> 90%) level of arterial oxygenation in patients with chronic obstructive pulmonary disease and moderate acute respiratory failure: 1) the initial arterial oxygen saturation on oxygen should be maximized whenever possible by increasing the inspiratory oxygen fraction; 2) this strategy seems feasible because neither the VM nor NPs worsen respiratory acidosis significantly; and 3) the Venturi mask (better than nasal prongs) should be recommended.

Acidosis, Respiratory↗
PubMed1999

Severe side effects and drug plasma concentrations in preterm infants treated with doxapram.

A high-performance liquid chromatography method has been developed for simultaneous determination of doxapram and its metabolites including ketodoxapram, the main and only active metabolite. The aim of the study was to evaluate this microtechnique and to report the cases involving severe adverse effects to determine toxic plasma levels in neonates. The method was found to be selective, and showed a good baseline separation of doxapram and metabolites. Recovery, linearity, intraday/interday precision, and limit of detection determined in aqueous solutions and in spiked plasma were satisfactory. The assay is simple, rapid, and plasma-sparing, which represents a true advantage in managing neonates. Case analysis was performed in two consecutive periods: 124 preterm infants in the first period and 173 in the second period. Severe toxic effects were observed in 4 cases in the first period, with doxapram plus keto-doxapram levels 9 mg/L. In the second period, only one case was observed. High-range plasma concentrations were significantly less frequent in the second period than in the first one. The authors conclude that measuring doxapram plus keto-doxapram in plasma may be of interest to avoid severe toxic effects in preterm neonates treated with doxapram.

Chromatography, High Pressure Liquid↗
PubMed1999

Patients with obstructive sleep apnea exhibit genioglossus dysfunction that is normalized after treatment with continuous positive airway pressure.

Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of pharyngeal closure during sleep. The pathogenesis of OSAS is unclear. We hypothesized that the genioglossus (GG), the most important pharyngeal dilator muscle, would be abnormal in patients with OSAS. Further, because treatment with continuous positive airway pressure (CPAP) is very effective clinically in these patients, we investigated the effects of CPAP upon the structure and function of the GG. We studied 16 patients with OSAS (nine of them at diagnosis and seven after having been under treatment with CPAP for at least 1 yr) and 11 control subjects in whom OSAS was excluded clinically. A biopsy of the GG was obtained in each subject, mounted in a tissue bath, and stimulated through platinum electrodes. The following measurements were obtained: maximal twitch tension, contraction time, half-relaxation time, the force-frequency relationship, and the response to a fatiguing protocol. The percentage of type I ("slow twitch") and type II ("fast twitch") fibers was also quantified. Patients with OSAS showed a greater GG fatigability than did control subjects (ANOVA, p < 0.001). Interestingly, this abnormality was entirely corrected by CPAP. Likewise, the percentage of type II fibers was significantly higher in patients with OSAS (59 +/- 4%) than in control subjects (39 +/- 4%, p < 0.001) and, again, these structural changes were corrected by CPAP (40 +/- 3%, p < 0.001). These results show that the function and structure of the GG is abnormal in patients with OSAS. Because these abnormalities are corrected by CPAP, we suggest that they are likely a consequence, not a cause, of the disease.

Humans↗
PubMed1998

Does the number of hypopnoeas influence therapy in patients with obstructive sleep apnoea?

The definition of hypopnoea varies widely between sleep laboratories. This study sought to evaluate the impact upon therapeutic decision of the most commonly used one, which defines hypopnoea as a reduction in airflow of 50% (or more) accompanied by a decreased blood oxygen saturation of 4% (or more) (Agency for Health Care Policy and Research). We studied 109 consecutive patients (99 male) with an apnoea-hypopnoea index (AHI) greater than 5. The same investigator evaluated each patient twice. First, the hypopnoea index (HI) was unavailable to him by study design, and judgment was based upon the number of apnoeas and the clinical situation of the patient. Thereafter, he evaluated all patients again, in random order, this time taking into account the AHI and the clinical condition of the patient. Therapeutic decision was compared at the end of the study. Mean age was 54 +/- 11 years (+/- SD) and body mass index 33 +/- 6 kg m-2. Most patients had normal spirometry and day-time arterial blood gases. Mean apnoea index (AI) was 35 +/- 24 h-1. Therapeutic decision based on the AI lead to conservative treatment (diet and sleep hygiene) in 32 cases and to active treatment in 77 patients [76 continuous positive airway pressure (CPAP) and one surgery]. The AHI was 40 +/- 24 h-1. The consideration of the number of hypopnoeas lead to a therapeutic change only in four patients (3.7%) (chi 2 = 0.36, P > 0.3). These four patients had an AI of 15, 7, 3, and 9 h-1 and an AHI of 22, 10, 46, and 17 h-1, respectively. Combined with their clinical data, this increase was considered a requirement for active treatment (CPAP). The most commonly used definition of hypopnoea has a small impact upon therapeutic decision in patients with obstructive sleep apnoea syndrome (OSAS). We suggest the need to develop new definitions of hypopnoea that incorporate other variables (neurophysiological, cardiovascular) of potential clinical relevance. Our results also show that the outcome of any new definition has to be assessed rigorously in terms of its clinical impact.

Adult↗
PubMed1998

Lead poisoning secondary to hyperthyroidism: report of two cases.

With long-term exposure to lead, lead accumulates in bone, where it is stored for years. These quiescent lead stores are mobilised when increased bone turnover occurs, and latent lead toxicity may then become symptomatic. Although Graves' disease is a common cause of increased bone turnover, to date hyperthyroidism has been implicated in lead poisoning only twice. We describe herein two cases of hyperthyroidism, one caused by toxic multinodular thyroid enlargement, the second by Graves' disease, leading to lead poisoning. Treatment of hyperthyroidism with radioactive iodine cured both hyperthyroidism and lead poisoning and no chelating agent therapy was necessary. Lead poisoning is an important environmental health problem, and physicians must be aware of the endocrine disorders such as hyperthyroidism and hyperparathyroidism that increase bone turnover, favouring lead mobilisation. Atypical symptoms should draw the physician's attention to the possibility of lead poisoning, particularly in workers with occupational exposure to lead and in areas where lead poisoning is endemic.

Adult↗
PubMed1997

Noninvasive ventilatory support after lung resectional surgery.

STUDY OBJECTIVES: To investigate the short-term effects of noninvasive ventilatory support (NIVS) on pulmonary gas exchange, ventilatory pattern, systemic hemodynamics, and pleural air leaks in patients submitted to elective lung resection. DESIGN: Prospective, randomized, parallel, and controlled investigation. SETTING: Thoracic Surgery Unit, Hospital Universitari Son Dureta, Palma Mallorca, Spain. PATIENTS: Nineteen patients electively submitted to lung resection because of varied clinical reasons. INTERVENTIONS: Medical therapy was standardized for all patients. Ten subjects received NIVS with a nasal ventilatory support system (BiPAP) during 1 h (study group). The remaining nine individuals constituted the control group. MEASUREMENTS AND RESULTS: Arterial blood gases, ventilatory pattern, systemic hemodynamics, and pleural air leaks were measured. Before surgery, there were no significant clinical or functional differences between groups. After surgery, and compared with preoperative measures, PaO2 decreased significantly (p<0.01) and to the same extent both in the study group (85.7+/-2.8 to 68.0+/-2.7 mm Hg) and the control group (83.6+/-2.5 to 67.3+/-2.6 mm Hg). In the study group, NIVS increased PaO2 (to 76.7+/-3.0 mm Hg; p<0.05) and decreased alveolar to arterial oxygen pressure gradient (P[A-a]O2) (27.2+/-2.7 to 17.6+/-2.3 mm Hg; p<0.05). This latter effect was still present 1 h after withdrawing NIVS. By contrast, PaO2 and P(A-a)O2 remained unchanged in the control group throughout the study. PaCO2, the ventilatory pattern, and systemic hemodynamics did not change significantly throughout the study in any group. Importantly, NIVS did not increase dead space to tidal volume ratio or worsen pleural air leaks. CONCLUSIONS: Short-term NIVS with a ventilatory support system improves the efficiency of the lung as a gas exchanger without noticeable nondesired side effects in patients submitted to lung resectional surgery.

Female↗
PubMed1996

Continuous positive airway pressure is effective in treating upper airway oedema.

The case of a patient with diffuse idiopathic skeletal hyperostosis (DISH) and upper airway oedema, is described. The patient presented with alveolar hypoventilation and obstructive apnoeas during sleep. Intravenous steroids (methylprednisolone, 160 mg.day-1) for 5 days did not reduce the oedema. However, it was rapidly reversed by the use of nasal continuous positive airway pressure (nCPAP). In addition, daytime pulmonary gas exchange was improved and sleep apnoea abolished. This beneficial effect made tracheostomy unnecessary. This case report suggests that CPAP can be a potentially useful therapeutic alternative to tracheostomy in the clinical management of upper airway oedema.

Aged↗
PubMed1996

Noninvasive ventilatory support does not facilitate recovery from acute respiratory failure in chronic obstructive pulmonary disease.

This investigation evaluates, in a prospective, randomized and controlled manner, whether noninvasive ventilatory support (NIVS) with bilevel positive airway pressure (BiPAP) facilitates recovery from acute respiratory failure (ARF) in patients with chronic obstructive pulmonary disease (COPD). Twenty four patients (mean age (+/-SEM) 68 +/- 2 yrs) with COPD (forced expiratory volume in one second (FEV1) at discharge 33 +/- 2% predicted), who attended the emergency room because of ARF (pH 7.33 +/- 0.01; arterial oxygen tension (Pa,O2) 6.0 +/- 0.2 kPa; arterial carbon dioxide tension (Pa,CO2) 7.9 +/- 0.3 kPa), were initially randomized. Four out of the 14 patients (29%) allocated to received NIVS did not tolerate it. Of the remaining 20 patients, 10 received NIVS with BiPAP in a conventional hospital ward during the first 3 days of hospitalization (two daytime sessions of 3 h duration each). All 20 subjects were treated with oxygen, bronchodilators and steroids. On the first and third hospitalization days, before and 30 min after withdrawing oxygen therapy and/or BiPAP ventilatory support, we measured peak expiratory flow, arterial blood gas values, ventilatory pattern, occlusion pressure (P0.1), and maximal inspiratory (MIP) and maximal expiratory (MEP) pressures. All patients were discharged without requiring tracheal intubation and mechanical ventilation. Hospitalization time was similar in both groups (11.3 +/- 1.3 vs 10.6 +/- 0.9 days, control vs BiPAP, respectively). Arterial oxygenation, respiratory acidosis and airflow obstruction improved significantly throughout hospitalization in both groups. By contrast, the ventilatory pattern, P0.1, MIP and MEP did not change. NIVS with BiPAP did not cause any significant difference between groups. We conclude that noninvasive ventilatory support with bilevel positive airway pressure does not facilitate recovery from acute respiratory failure in patients with chronic obstructive pulmonary disease. Furthermore, a substantial proportion of patients (29%) do not tolerate noninvasive ventilatory support under these circumstances. From these results, we cannot recommend the use of noninvasive ventilatory support with bilevel positive airway pressure in the routine management of chronic obstructive pulmonary disease patients recovering from acute respiratory failure.

Aged↗
PubMed1996

Long-term effects of nasal intermittent positive-pressure ventilation on pulmonary function and sleep architecture in patients with neuromuscular diseases.

STUDY OBJECTIVE: This article evaluates the long-term clinical and physiologic effects of nocturnal nasal intermittent positive-pressure ventilation (NIPPV) in patients with neuromuscular disease. METHODS: Before and after 18 +/- 2 months of NIPPV, we measured during the daytime arterial blood gases, lung mechanics, and respiratory muscle strength in 8 patients (51 +/- 5 years; mean +/- SEM). Sleep parameters were also evaluated at 10 +/- 2 months. RESULTS: All patients tolerated NIPPV and none required hospitalization during follow-up. After NIPPV, daytime arterial PO2 increased (71 +/- 4 to 81 +/- 2 mm Hg; p < 0.05) and arterial PCO2 decreased (46 +/- 3 to 41 +/- 1 mm Hg; p < 0.05). The change of PaO2 after NIPPV was related to its baseline value (r2 = 0.78, p < 0.05). Vital capacity (50 +/- 6% predicted), total lung capacity (63 +/- 4% predicted), alveolar-arterial oxygen gradient (20 +/- 3 mm Hg), and maximal inspiratory (39 +/- 9% predicted) or expiratory (32 +/- 5% predicted) pressures did not change after NIPPV. The apnea-hypopnea index fell from 22 +/- 6 to 1 +/- 1 (p < 0.05), and both sleep architecture and sleep efficiency (from 59 +/- 8% to 83 +/- 5%; p < 0.05) were enhanced. The time spent with an arterial oxygen saturation (SaO2) value below 90% decreased from 160 +/- 53 min to 8 +/- 4 min (p < 0.05). Mean (88 +/- 3 to 95 +/- 1%; p < 0.05) and minimal nocturnal SaO2 (67 +/- 5 to 89 +/- 1%; p < 0.001) improved after NIPPV. CONCLUSIONS: In patients with neuromuscular disease, long-term NIPPV is well tolerated and easy to implement clinically. In these patients, long-term NIPPV improves daytime arterial blood gas values and sleep-disordered breathing. However, it does not modify lung mechanics or respiratory muscle strength.

Adult↗