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Background The efficacy of enzyme replacement therapy (ERT) in patients at an advanced stage of Pompe disease has only been addressed in a few studies. Our objective was to assess the long term effects of ERT in a cohort of patients with severe Pompe disease. Methods We identified patients from the French Pompe Registry with severe respiratory failure and permanent wheelchair use (assisted walk for a few meters was allowed) when starting ERT. Patients' medical records were collected and reviewed and respiratory and motor functions, before ERT initiation and upon last evaluation were compared. Results Twelve patients (7 males) were identified. Median age at symptom onset was 24 years [IQR = 15.5; 36.0]. At baseline ventilation was invasive in 11 patients and noninvasive in one, with a median ventilation time of 24 h [IQR = 21.88; 24.00] (min 20; max 24). ERT was initiated at a median age of 52.5 years [IQR = 35.75; 66.50]. Median treatment duration was 55 months [IQR = 39.5; 81.0]. During observational period no adverse reaction to ERT was recorded, five patients (41.67%) died, three decreased their ventilation time by 30, 60 and 90 min and two increased their assisted walking distance, by 80 and 20 m. Conclusion Some patients at a very advanced stage of Pompe disease may show a mild benefit from ERT, in terms of increased time of autonomous ventilation and of enlarged distance in assisted walk. ERT can be initiated in these patients in order to retain their current level of independence and ability to perform daily life activities.

Resume Introduction La necrose medullaire, caracterisee par une necrose des progeniteurs hematopoietiques, des ilots adipocytaires et de la trame de reticuline, est une pathologie tres rare. Observation Nous rapportons l’observation d’une patiente de 62 ans admise en reanimation pour une necrose medullaire etendue compliquant l’evolution d’une thrombocytemie essentielle associee a un choc septique sans germe retrouve, amenant rapidement au deces dans un contexte de defaillance multiviscerale. Il s’agit, a notre connaissance, du deuxieme cas rapporte dans la litterature a ce jour. Sa presentation clinique est aspecifique et associe douleurs osseuses et fievre, et parfois un syndrome d’insuffisance medullaire. La biologie peut montrer des cytopenies diversement associees, une elevation des LDH et des phosphatases alcalines osseuses. Le diagnostic est histologique, obtenu apres biopsie osteomedullaire. La necrose est dite etendue si elle concerne plus de 50 % du cylindre biopsique. Cette pathologie est associee dans 90 % des cas a une hemopathie maligne (notamment les leucemies) ou a une tumeur solide le plus souvent gastro-intestinale ou pulmonaire. D’autres etiologies regroupent la drepanocytose ou le syndrome catastrophique des anticorps antiphospholipides, la thrombocytemie essentielle etant exceptionnellement responsable d’une necrose medullaire. Conclusion Toutes causes confondues, le pronostic de la necrose medullaire etendue est generalement sombre sauf en cas de traitement precoce et intensif, notamment chez les patients drepanocytaires chez qui peut s’observer une regeneration medullaire complete.

Anorexia nervosa can be a life-threatening eating disorder when complicated with electrolyte disturbance, gelatinous transformation of the bone marrow or starvation induced acute hepatitis. We report a 43-year-old woman suffering from anorexia nervosa for more than 25 years, who was admitted in intensive care unit for a fluctuating level of consciousness related to starvation-induced acute hepatitis. Gelatinous transformation of the bone marrow was also diagnosed. Those two entities are rare and, to our knowledge, have not been previously reported jointly in anorexia nervosa.

• - Neurologic control of lung vascular tone ◦ • Cholinergic system: - - mediators - - muscarinic receptors - - mechanisms of action ◦ • Non-adrenergic non-cholinergic system: - - definition - - mediators ◦ • Reflex mechanisms ◦ • Interactions between endothelium and neural mechanisms • - Humoral control of lung vascular tone ◦ • Atrial natriuretic peptide ◦ • Vasopressin ◦ • Angiotensin-II ◦ • Kinins ◦ • Histamine ◦ • Serotonin ◦ • Free radicals: - - hydrogen peroxide - - superoxide anion - - peroxinitrite

Problems related to the study of pulmonary vasomotility - Constriction/dilation of the vascular smooth muscle: ionic mechanisms · Calcium movements: - through sarcoplasmic reticulum - through cytoplasmic membrane · Potassium channels · C-protein kinases · G-proteins · Cyclic nucleotids - The endothelium · Paracrine role of the endothelial cell: - nitric oxide - endothelium-derived hyperpolarizing factor - eicosanoids - endothelins · Endothelial metabolism of vasoactive peptides: - angiotensin-converting enzyme - neutral endopeptidase - endothelin-converting enzyme.

Weaning patients with heart failure who have required mechanical ventilation remains challenging. We evaluated echocardiographic indexes and N-terminal pro-brain natriuretic peptide (NT-proBNP) as markers of acute cardiac dysfunction before and after spontaneous breathing trials (SBT) in such patients to assess their ability to predict subsequent successful extubation.Forty-four patients who underwent their first SBT were prospectively included. Plasma levels of NT-proBNP and transthoracic echocardiography indices including cardiac index, E/A ratio and E/Ea ratio were recorded immediately before commencing and just before the end of SBT.Ten patients (22.7%) failed their SBT. No significant difference was observed concerning baseline echocardiographic data and NT-proBNP level between the patients who succeeded the SBT or those that failed. Cardiac index increased significantly at end-SBT in patients who passed (3.3 [3.06-3.77] vs. 3 [2.68-3.3] L/min/m(2), P0.001), whereas it remained unchanged in those that failed. E/Ea ratio (16.8 [8.5-27.3] vs. 10.7 [6.7-20.5], P=0.006) and NT-proBNP level (8199 [3106-10949] vs. 4200 [1855-7125] pg/mL, P=0.004) increased significantly in those who failed the SBT, in contrast to the weaning success group where they remained unchanged.Neither NT-proBNP level nor the studied echocardiographic indices before SBT were able to predict SBT outcome in patients presenting with severe heart failure. Failure to increase the cardiac index and increases in both E/Ea ratio and NT-proBNP levels were seen at end-SBT in patients who failed the SBT, and may reflect failure of myocardial reserve to cope with the stress of SBT.

Anorexia nervosa can be a life-threatening eating disorder when complicated with electrolyte disturbance, gelatinous transformation of the bone marrow or starvation induced acute hepatitis. We report a 43-year-old woman suffering from anorexia nervosa for more than 25 years, who was admitted in intensive care unit for a fluctuating level of consciousness related to starvation-induced acute hepatitis. Gelatinous transformation of the bone marrow was also diagnosed. Those two entities are rare and, to our knowledge, have not been previously reported jointly in anorexia nervosa.

Bone marrow necrosis is a very rare condition which is characterized by a necrosis of hematopoietic progenitors, adipocytes and reticulin network.We report a 62-year-old woman admitted to an intensive care unit for an essential thrombocytemia associated with bone marrow necrosis complicated by septic shock and progressive multi-organ failure. To our knowledge, this is the second case reported in the literature. The clinical presentation of bone marrow necrosis includes non-specific symptoms such as fever, bone pain and sometimes a clinically significant medullar insufficiency syndrome. Biology can reveal cytopenias, elevated LDH and alkaline phosphatase serum levels. The diagnosis is confirmed by bone marrow trephine biopsy. Bone marrow necrosis is classified as extensive if more than 50% of the bone marrow biopsy show necrosis. Haematological malignancies (particularly leukaemia), and solid malignant tumours (particularly gastro-intestinal or lung cancers) represent up to 90% of aetiologies and must be actively researched. Also, sickle cell disease and catastrophic anti-phospholipid syndrome must also be investigated. Essential thrombocytemia remains an exceptional cause of bone marrow necrosis.Overall the prognosis of bone marrow necrosis is poor unless appropriate and intensive treatment, especially for sickle cell disease in which complete medullar regeneration has been observed.

Resume L'influence de la pause de fin d'inspiration (EIP) a frequence, volume courant, FIO2, et Ti/Ttot constants a ete etudiee chez 11 patients, sans antecedent respiratoire, en ventilation controlee pour coma sequellaire d'une atteinte cerebrable. Sous neurosedation et curare, ils ont ete soumis a 2 rapports Ti/Ttot : un rapport conventionnel Ti/Ttot = 0,35 comprenant une EIP de 0,10, et 20 p. 100 et un rapport allonge Ti/Ttot = 0,5 avec et sans pause de 20 p. 100. L'ordre d'administration de chaque mode ventilatoire a ete randomise. Les mesures des debits et volumes (pneumotachographe de Fleish no 2), des pressions des voies aeriennes, des variations de CRF (plethysmographie d'inductance), des gazometries arterielles et veineuses melees, des parametres hemodynamiques et des distributions des rapports VA/Q pulmonaires par la methode des gaz inertes ont ete realisees. Les differents parametres ont ete compares par une analyse de variance. En ventilation avec un rapport Ti/Ttot conventionnel, la suppression de la pause ne provoque qu'une augmentation de l'effet shunt associee a une distribution plus heterogene de la ventilation. Ces variations sont insuffisantes pour provoquer une modification gazometrique. Par contre, la suppression du temps de pause provoque une diminution du pic d'insufflation. A Ti/Ttot = 0,5, la suppression du temps de pause provoque un deplacement des courbes de distribution de la ventilation et de la perfusion vers les bas VA/Q conduisant a une hypoventilation relative avec augmentation de PaCO2. L'absence de variation de PaO2 est liee a l'augmentation de PvO2 due a l'elevation de Qtot en rapport avec la baisse de la pression intrathoracique. Pour les 2 Ti/Ttot, il n'y a pas de variation significative de CRF. Les memes resultats gazometriques sont obtenus quand les patients sont soumis a Ti/Ttot = 0,67 sans pause. En conclusion, en ventilation a rapport Ti/Ttot conventionnel, l'absence de pause est compensee par l'effet benefique lie a la diminution des debits d'insufflation ; par contre, lors de l'utilisation de Ti/Ttot allonges, l'EIP est necessaire afin de permettre une meilleure distribution VA/Q.

Peripheral nerve biopsies (PNB) from four children suffering from subacute or chronic inflammatory demyelinating polyneuropathy were studied by electron microscopy. Remyelinating features with onion bulb formations, inflammatory cell infiltrates and active demyelinating lesions were strongly suggestive of the disease. In the first case, a second PNB, performed after 7 months of severe subacute course, showed a striking evolution of the lesions. In the second case and in spite of severe neurological symptoms, the PNB was almost normal, suggesting that inflammatory lesions were mainly located in the proximal parts of the nerve. No signs of active demyelination could be seen in the third case but onion bulb formations and inflammatory cell infiltrates were present. In the fourth case, characteristic lesions of active demyelination were associated with a history of familial polyneuropathy; this association suggests an auto-immune process in certain kindreds with hereditary motor and sensory neuropathy.

Bilateral adrenal hematoma is an uncommon cause of acute adrenal insufficiency. An association with thrombopenia induced by low-molecular-weight heparin even more so. Diagnosis is difficult as the clinical manifestations mimic septic shock.A 63-year-old woman developed acute adrenal insufficiency due to bilateral adrenal hematoma following severe thrombopenia induced by low-molecular-weight heparin prescribed after an orthopedic operation. Outcome was favorable.Acute adrenal insufficiency must be entertained as a possible diagnosis in patients with heparin-induced thrombopenia.

beta-agonist bronchodilators are known to influence gas exchange and ventilation-perfusion relationships in asthmatic patients, where they induce hypoxaemia via hypoxic vasoconstriction. As this effect could have serious consequences in chronic obstructive pulmonary disease (COPD) patients with chronic hypoxaemia, alternative agents have been sought. It has been shown that inhaled anticholinergic drugs may be of value in this condition. In the present study, we compared the effects of salbutamol (Sb) and ipratropium bromide (IB) inhalation on gas exchange in 15 patients with stable COPD. All patients had a history of COPD (mean arterial oxygen tension (Pa,O2) = 8.2 +/- 1.0 kPa (61.8 +/- 7.3 mmHg) forced expiratory volume in one second (FEV1) = 39 +/- 12%; FEV1/vital capacity (VC) = 42 +/- 6%) and no evidence of acute respiratory failure. Haemodynamic and gas exchange data were recorded after right catheterization by the multiple inert gas elimination technique. Measurements were made under basal conditions, after two puffs of freon propellant (placebo) and after two puffs of either 200 micrograms Sb or 200 micrograms IB in a randomized design. Sb and IB reduced airway resistances to the same extent, but had no significant influence on the haemodynamic and ventilation parameters. There was a slight but significant decrease in arterial carbon dioxide tension (Pa,CO2) = 6.0 +/- 0.8 versus 6.4 +/- 0.8 kPa (45.4 +/- 5.9 versus 47.9 +/- 6.3 mmHg) p0.05 with an enhanced perfusion distribution heterogeneity and a slight improvement in ventilation homogeneity shown by a decrease of the decimal logarithm of SD of the ventilation distribution (LogSDV) after inhalation of IB relative to control. Since these alterations did not affect arterial oxygen tension we concluded that inhalation of these doses of salbutamol or ipratropium bromide do not affect gas exchange in patients with stable chronic obstructive pulmonary disease. The normal home treatment: inhalation of two puffs of these bronchodilating drugs thus appears to be safe. The choice of agent will depend on the extent of the bronchodilator effect in a given individual.

Nitric oxide (NO) has been reported to be an endothelium-derived relaxing factor, and hypoxic pulmonary vasoconstriction seems to be enhanced by inhibitors of endothelially dependent vascular relaxation. We examined the circulatory effects of inhalation of 15 ppm NO in air in 14 hypoxic patients suffering from chronic obstructive pulmonary disease (COPD). Of these patients 4 breathed 100% O2 before NO. The effects of NO inhalation on pulmonary gas exchange were also studied in 12 of these patients using the multiple inert gas elimination technique, 3 of whom breathed air, 100% O2, and 15 ppm NO in air in succession. Under baseline conditions, both mean +/- SD pulmonary artery pressure and pulmonary vascular resistance were increased (Ppa = 24.3 +/- 10.4 mm Hg and PVR = 3.3 +/- 1.1 mm Hg/L/min, respectively). Although the pulmonary circulatory effects were not immediate, with no detectable changes after 1 min NO inhalation, Ppa and PVR fell significantly (-19.1 +/- 10.5%, p0.02 and -29.3 +/- 15.1%, p0.02, respectively) after 10 min NO inhalation. Moreover, the extent of the NO-induced reduction in Ppa was found to depend on the level of baseline pulmonary arterial hypertension. No systemic circulatory effects were observed. The mean VA/Q ratio and the dispersion of ventilation and blood flow distributions were not altered by NO inhalation, although there was a significantly higher percentage of ventilation (7.3 +/- 7.3%, p0.05) in poorly and unperfused areas (VA/Q10).(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of inspiratory flow rate (TI), without changing respiratory frequency, tidal volume, and FIO2, was investigated in 11 normal lungs in patients undergoing mechanical ventilation because of central respiratory failure due to stable coma. The patients were anesthetized and paralyzed. They first received a conventional ventilation (TI = 25 percent, pause = 10 percent) and then, were submitted to four different TI values, randomly administered without any end-inspiratory pause (EIP) (TI = 20 percent; TI = 33 percent; TI = 50 percent; TI = 67 percent). In the middle and at the end of the procedure, a return to basal conditions was introduced. At each ventilator setting, the following were obtained: respiratory flow (Pneumotachograph Fleish No. 2), airway pressure, FRC changes (inductive plethysmography), arterial and mixed venous blood gases, hemodynamic data, and VA/Q ratios distribution using multiple inert gases technique. EIP suppression provides a significant increase in VA/Q mismatch (until TI = 50 percent) and in shunt effect (between 3 and 9 percent of cardiac output [QT]). The absence of simultaneous PaO2 change is due to increasing PVO2 linked to a higher QT. The shorter the TI, the higher the PaCO2 connected with a relative alveolar hypoventilation. However, increasing TI without EIP significantly decreases ventilation distribution inequalities. This improvement is concomitant with a rise in FRC (FRC67-FRC20 = 0.340 +/- 0.450, p0.05) without any change in other variables or auto-PEEP production. In summary, in subjects with very slight mechanical lung impairment (peak inspiratory pressure = 20.5 +/- 5.3 cm H2O at TI = 20 percent and 15.2 +/- 3.3 cm H2O at TI = 67 percent), this study confirms the deleterious effect of EIP suppression and TI decrease. One can compensate for this effect of EIP absence by increasing TI as soon as it reaches TI = 67 percent, ie, inverse ratio ventilation.

Recent multi-centre studies have shown that high doses of Almitrine (100-200 mg per day), lead to a significant improvement in the hypoxaemia of patients presenting with chronic airflow obstruction, but that a high blood level (greater than 500 ng/ml) is often seen after 1 year, sometimes associated with signs of peripheral neuropathy. In order to maintain Almitrine blood levels in the range 200-300 ng/ml we have used an intermittent regime (with a "window" of 1 month every 3 months) and a dose limited to 100 mg per day. 102 hypoxic patients with chronic airflow obstruction, who were in a stable state were included. 65 patients were in the Almitrine group (A) and 37 patients in the placebo group (P). The treatment lasted for 1 year. In addition there was a 3 monthly follow up with arterial blood gases and spirometry, a clinical neurological examination and also electrophysiology, initially and after 6 and 12 months. 43% of patients in group A and 32% of patients in group P, left the study, most often due to poor cooperation, but sometimes as a result of side effects. After 12 months the PaO2 rose significantly in group A from 59.1 +/- 0.7 to 65.8 +/- 1.6 mmHg (p less than 0.001) whilst it was not changed in group P. The PaCO2 did not change in either group. On the other hand there was a significant fall in the subgroup of patients with hypercapnia in group A (p less than 0.001). The outcome of the neurological and electrophysiological assessments did not show any significant difference between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-nine patients with fulminant hepatic failure and at least grade III encephalopathy were treated by haemodialysis with a polyacrylonitrile membrane. Aetiology was toxic in five patients, viral in eleven (2 due to hepatitis A virus and 9 presumed due to hepatitis B virus), not found in thirteen. Each patient was dialysed for 4 h every day, until he regained consciousness or died. Conscious level was improved after dialysis in 59% of patients. Thirteen patients survived (44.8%) :4 toxic hepatitis, 4 viral hepatitis B, 1 viral hepatitis A, 4 hepatitis of unknown aetiology. A comparison of plasma concentrations of amino acids measured by chromatography before and after 113 periods of haemodialysis in 23 patients showed significant decrease in aromatic amino acids (p less than 0.001), a significant increase in two branched-chain amino acids :leucine (p less than 0.001) and isoleucine (p less than 0.001), and a significant increase in Fischer's ratio (p less than 0.001). In survivors, factor V concentration on admission and Fischer's ratio on admission were significantly higher than in those who died (p less than 0.02 for both), but there was no significant difference in the difference between Fischer's ratio before and after haemodialysis. Haemodialysis was well tolerated, except for short periods of hypotension and a small but significant fall in platelet counts. Improvement in cerebral function during haemodialysis was previously demonstrated by various authors, but the effect on survival rate remained controversial. The survival rate obtained in this controlled study is clearly higher than those obtained by conservative management alone.

Pulmonary gas exchange in Andean natives (n = 8) with excessive high-altitude (3,600-4,200 m) polycythemia (hematocrit 65.1 +/- 6.6%) and hypoxemia (arterial PO2 45.6 +/- 5.6 Torr) in the absence of pulmonary or cardiovascular disease was investigated both before and after isovolemic hemodilution by use of the inert gas elimination technique. The investigations were carried out in La Paz, Bolivia (3,650 m, 500 mmHg barometric pressure). Before hemodilution, a low ventilation-perfusion (VA/Q) mode (VA/Q less than 0.1) without true shunt accounted for 11.6 +/- 5.5% of the total blood flow and was mainly responsible for the hypoxemia. The hypoventilation with a low mixed venous PO2 value may have contributed to the observed hypoxemia in the absence of an impairment in alveolar capillary diffusion. After hemodilution, cardiac output and ventilation increased from 5.5 +/- 1.2 to 6.9 +/- 1.2 l/min and from 8.5 +/- 1.4 to 9.6 +/- 1.3 l/min, respectively, although arterial and venous PO2 remained constant. VA/Q mismatching fell slightly but significantly. The hypoxemia observed in subjects suffering from high-altitude excessive polycythemia was attributed to an increased in blood flow perfusing poorly ventilated areas, but without true intra- or extrapulmonary shunt. Hypoventilation as well as a low mixed venous PO2 value may also have contributed to the observed hypoxemia.

Several outbreaks of fatal opportunistic infections and tumors have recently been reported among homosexual men in the United States. Almost all patients had evidence of cellular immunodeficiency. We have studied a French homosexual man with fatal central nervous system toxoplasmosis. Morphological features (light and electron microscopy) of toxoplasma encephalitis are described.

Three serious cases of status asthmaticus with severe hypercapnic acidosis unresponsive to adequate conventional therapy were treated by halothane. The efficiency of this treatment was assessed by the clinical state of the patient, the blood gases and the changes in peak airway pressure. Two patients improved dramatically in less than 24 h. No signs of cardiac toxicity of this drug were noted in spite of acid-base disturbances. These three cases showed the beneficial effect of halothane's-beta 2 stimulation in the treatment of status asthmaticus.

As has been shown during the course of experimental allergic neuritis, in the Guillain-Barre syndrome there is an invasion of the myelin sheath in certain fibres by a mononuclear cell, with an intact axon. In a series of 45 cases we have been able to show this feature in 31 cases. In certain cases the cytoplasm prolongation of the invading cell was seen in the myelin sheath, forcing apart two neighbouring layers.

Twenty-nine patients with fulminant hepatic failure and at least grade III encephalopathy were treated by haemodialysis with a polyacrylonitrile membrane. Aetiology was toxic in five patients, viral in eleven (2 due to hepatitis A virus and 9 presumed due to hepatitis B virus), not found in thirteen. Each patient was dialysed for 4 h every day, until he regained consciousness or died. Conscious level was improved after dialysis in 59% of patients. Thirteen patients survived (44.8%) :4 toxic hepatitis, 4 viral hepatitis B, 1 viral hepatitis A, 4 hepatitis of unknown aetiology. A comparison of plasma concentrations of amino acids measured by chromatography before and after 113 periods of haemodialysis in 23 patients showed significant decrease in aromatic amino acids (p less than 0.001), a significant increase in two branched-chain amino acids :leucine (p less than 0.001) and isoleucine (p less than 0.001), and a significant increase in Fischer's ratio (p less than 0.001). In survivors, factor V concentration on admission and Fischer's ratio on admission were significantly higher than in those who died (p less than 0.02 for both), but there was no significant difference in the difference between Fischer's ratio before and after haemodialysis. Haemodialysis was well tolerated, except for short periods of hypotension and a small but significant fall in platelet counts. Improvement in cerebral function during haemodialysis was previously demonstrated by various authors, but the effect on survival rate remained controversial. The survival rate obtained in this controlled study is clearly higher than those obtained by conservative management alone.

A double blind study of effects of a low dose of almitrine has been performed in patients with severe chronic obstructive lung diseases. Besides hemodynamic and ventilation data, ventilation-perfusion ratio distribution was measured by the inert gas method in order to try to explain the improvement in blood gases caused by this drug. At the dose of 1.5 mg/kg almitrine produces : 1) an increase in ventilation and PaO2, 2) no change in pulmonary vascular resistances compared to a rise on placebo, 3) a drop of 4% in the percentage of cardiac output perfusing low VA/Q lung units with a concomitant increase in lung units with VA/Q ratio between 0.1 and 10, and 4) no significant change in the distribution of ventilation. The change in the distribution of blood flow is one of the causes of the rise in PaO2, but its mechanism is at yet not clear. The present results suggest arterial vasoconstriction in units with very low VA/Q accompanied by diversion of blood flow towards lung units with higher VA/Q ratio.

The effectiveness of assisted ventilation at home, especially in the case of tracheostomized patients, has been nearly established at the present time. The experience of various centers in France, having or not the support of an independent structured organization, shows that the setting-up and supervision of such therapy can be effectively carried out. Nevertheless, difficult choices remain. Some indications are still questionable, such as the choice of the respirator if the patient has not been tracheostomized. The type of organization is not univocal and could perhaps depend on the number of patients to be cared for. In any case, in the years to come, the experience of the different teams and the technical progress made will lead to a solution to the problems raised: a decrease in the number of hospitalizations and more comfort for the patients can be hoped for.

65 biopsies of peripheral nerve from patients suffering from Guillain-Barré syndrome were studied by electron microscopy. In 48 cases there was macrophagic invasion of the Schwann cells of certain myelinated fibers, and in 32 of these cases some myelin sheaths were stripped away by an elongated macrophagic process. Vesicular disruption of the myelin sheath was observed in only 8 cases and in less than 1% of the myelinated fibers. Uncompacted myelin lamellae were observed in a few myelinated fibers. These ultrastructural lesions are analysed and commented on with a view to selecting patients who are to undergo plasma exchange.

Ventilation and perfusion distributions were measured in the patients with COPD breathing room air and normoxic helium-oxygen mixture (heliox) successively, using the multiple inert gas method. The D (A-a) O2 were calculated from ideal alveolar gas (Ai) and with West's gas mean model (A). Measured PaO2 and predicted PaO2 were compared during room air and heliox breathing. There were no change in overall distributions and in D (Ai-a) while D (A-a) O2 increase significantly during heliox breathing and the predicted PaO2 were significantly higher than the measured PaO2. Heliox breathing does not seem to change parallel heterogeneity in COPD. These results suggest an impairment of series heterogeneity and O2 diffusion during heliox breathing.

Although the respiratory stimulant effects of almitrine bismesylate (AB) via an action on the peripheral chemoreceptors have been demonstrated, the mechanism of its intrapulmonary action has not yet been elucidated. In order to abolish the stimulation of ventilation, observed in studies on spontaneously breathing patients, an investigation of patients suffering from severe COPD under constant mechanical ventilation, with FIO2 = 0.21, during the weaning period was carried out. Eighteen patients were randomly divided into 2 groups (9 receiving 1.5 mg/kg AB and 9 receiving placebo). The ventilatory and hemodynamic variables, blood and alveolar gases, and the VA/Q ratio distributions using the multiple inert gas technique were collected before treatment with drug or placebo, as well as 90 and 180 min afterwards. The PaO2 was found to be raised 90 min after AB administration (+57 +/- 3.9 mm Hg, p less than 0.01) and remained above the baseline value at 180 min (+5.4 +/- 4.6 mm Hg, p less than 0.01). Compared with those in the placebo group, these increases were significant (p less than 0.01). A slight decrease in PaCO2 but similar in the 2 groups was observed despite constant ventilation. The hemodynamic data were the same for the 2 groups. The changes in overall criteria of the distributions (mean VA/Q and SD) were small. The main finding was a decrease in the percentage of the perfusion flowing through the true shunt and the underventilated areas after AB treatment. In the control group, the blood flow percentage in the true shunt and low VA/Q units was either stable or increased.(ABSTRACT TRUNCATED AT 250 WORDS)

We report a case of severe pulmonary embolism in a 37 years old man admitted to the intensive care unit for severe acute respiratory failure. The presenting signs and symptoms were typical for severe pulmonary oedema. Chest radiograph shortly after admission showed local alveolar shadows. In the absence of sepsis, haemodynamic evidence of left ventricular failure on catheterization of the right heart and because of the history of the recent illness, a tentative diagnosis of pulmonary embolism was made. The diagnosis was confirmed by selective pulmonary angiography. The latter demonstrated that pulmonary oedema had been localized only in areas with patent pulmonary arteries and, in addition, confirmed that left ventricular function was normal. Such a pattern of local pulmonary oedema is uncommon in patients and is reminiscent of that observed in animal experiments with severe pulmonary arterial obstruction and overperfusion of unblocked territories. Possible mechanisms of overperfusion oedema are discussed and the hypothesis that humoral factors may increase the permeability of pulmonary microvasculature in cases of severe pulmonary embolism is put forward.

The efficacy and tolerance of a nasal CPAP device marketed in France (Pression +, Sefam) for the treatment of obstructive sleep apnoea syndromes have been evaluated in a co-operative trial including 12 patients. This study confirmed the efficacy of nasal CPAP on sleep parameters: total sleep time was increased; light non-REM sleep was diminished; slow-wave sleep and REM sleep were augmented; sleep apnoeas were eliminated completely or almost completely; oxygen saturation was markedly improved. At one month follow-up, most clinical features were improved; daytime blood gases showed little change but the number of red cells was decreased. On the whole, the tolerance was good in this highly motivated group of patients: eleven patients (92%) were willing to continue their home treatment with the same device. Most difficulties were due to the making of a tailored molded nasal mask and its use during sleep.

Fourteen patients suffering from severe but stable chronic airway obstruction were studied while breathing room air and mildly hyperoxic mixture (26%). The data were collected at the end of each 30 min randomized breathing period. The multiple inert gas elimination technique was used to detect alterations in ventilation-perfusion (VA/Q) mismatching. Ventilatory, arterial and mixed venous blood gases, and hemodynamic measurements were made simultaneously. To show a possible effect of O2 on hypoxic pulmonary vasoconstriction (HPV), the fractional part of cardiac output perfusing low VA/Q areas was separated using as upper limit of VA/Q the compartments with PAO2 70, 60 and 50 mmHg while breathing oxygen, compared to the percentage of blood flow in the same areas limited by the same VA/Q unit in air breathing conditions. Only a few changes due to O2 are statistically significant: 1) a rise in PaO2 (+20.2 +/- 8.3 mmHg) and PvO2 (+4.2 +/- 2.18 mmHg) without any change in ventilation, respiratory frequency, pH, PaCO2, haemodynamics and overall criterion of distribution; 2) a moderate increase in inert gas dead space; 3) an increase in the percentage of blood flow under the limit when chosen at 50 mmHg (+3 +/- 2.8%). This change could be related to an inhibition of HPV response while breathing O2 in compartments previously placed above the limit in air. Consequently, their VA/Q decrease and their perfusions are summed with those under the limit in O2. These data suggest that mild hyperoxia has a slight but real deleterious effect on pulmonary gas exchange.

As has been shown during the course of experimental allergic neuritis, in the Guillain-Barré syndrome there is an invasion of the myelin sheath in certain fibres by a mononuclear cell, with an intact axon. In a series of 45 cases we have been able to show this feature in 31 cases. In certain cases the cytoplasm prolongation of the invading cell was seen in the myelin sheath, forcing apart two neighbouring layers. In five cases we have furthermore observed the presence of mononuclear cells located either between the myelin and the axon which is deformed, or on the inside of the axon. Such an anomaly was frequent in one recent case and was occasionally found in four other cases.

From a study conducted in 1981 in patients with chronic obstructive pulmonary disease breathing spontaneously, it was concluded that almitrine ensured a more even distribution of ventilation-perfusion ratios in the lung. Another study has recently been undertaken to suppress the effects of stimulated ventilation observed and to measure more accurately the pulmonary vascular effect of this new drug. This was a randomized double-blind drug versus placebo trial using the same doses of almitrine (1.5 mg/kg orally) in patients of the same type under stable artificial respiration controlled by repeated measurements of ventilation during the weaning period at the end of an episode of acute respiratory failure. The preliminary results obtained in one-half of the patients (4 under almitrine, 4 under placebo) are reported. There was little difference in haemodynamic values between the two groups. Improvement in PaO2 was maximum 90 min after almitrine was administered and varied from 0.7 to 1.4 kPa; there was no modification in the control group. In the absence of any change in ventilation and respiratory rate, perfusion was reduced in lung areas with low ventilation-perfusion ratio. These partial results seem to confirm that almitrine exerts a moderate, though real, effect on pulmonary vessels.