[Management of acute carbon monoxide poisoning. Normobaric or hyperbaric oxygen].
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Biomedical subjects
Publications and source records attributed to P Gajdos.
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HLA association with myasthenia gravis (MG) has been studied in a series of 114 patients using class I and class II genotyping after PCR amplification. Positive association was found with DR3, particularly in women (RR = 2.6) and in early MG onset (RR = 3.4). DRB1, DRB3, DQB1, DQA1 and B (B8 and B18) genotyping revealed that the association was predominantly with the B8 DRB1*03 DRB3*0101 DQB1*0201 DQA1*0501 ancestral haplotype. This haplotype frequency was also increased in patients with thymic hyperplasia (RR = 3.5) and was greatly reduced in patients with thymoma (RR = 0.35). Sixteen out of 48 patients carrying this 8.1 ancestral haplotype showed absence of B8 (n = 4) or of DR3 (n = 12). HLA class II genotyping further revealed the existence of two other significant associations. MG was positively associated with the DQB1*0604 allele (RR = 3.4), particularly in patients with thymoma (RR = 5.7). Furthermore, the disease was negatively associated with DR1 in females (RR = 0.32). These data suggest that MG is placed under the control of at least three distinct genes: (1) a class II predisposing gene in the 8.1 ancestral haplotype; (2) a thymoma-associated class II allele on the DQB1*0604 haplotype; and (3) a protective allele DR1.
From 1985 to 1990, the French Society of Hemapheresis (SFH) managed a National Registry of Plasma Exchange (PE) which included a data collection service, computer data input and statistical analysis of the total operation. The management of this registry did, however, encounter some problems. In 1991, an on-line computer access file was created, permitting French centers to input their data in Minitel Registry System. As a result, analysis on a national scale has proven more time-effective and data collection errors have been noticeably reduced. In January 1991, 43 centers were connected to the Minitel System. Only 17 centers, representing 4706 PEs, entered their data directly to the Minitel System during 1991 and, during the first term of 1992, a further 11 centers, representing 3258 PEs, communicated their data on paper in batch mode. The final total for 1990 was: 26 centers representing 860 patients and 7991 PEs. It is likely that some small imperfections have already developed during processing of the 1991 data, but these will be corrected as they are entered into the system. With the implementation of the Minitel System the French PE Registry represents a more accurate picture of plasmapheresis activity in France.
In this paper there is an outline of the organisation and the results of domiciliary ventilation for patients with neuromuscular diseases where there are serious respiratory problems, in relation to special facilities that have been made available in France. The clinical and economic benefits are stated, in particular concerning the situation in the greater Paris area.
Myasthenia gravis (MG) is an autoimmune disease associated with thymic abnormalities (hyperplasia and thymoma). With classical typing method, no clear association was observed between HLA class II and MG disease except in a subgroup of patients with hyperplasia. The aim of our work was to investigate a possible correlation between HLA class II alleles and MG disease using molecular typing which was proved to be much more informative in many diseases. Using polymerase chain reaction and 75 sequence-specific oligonucleotide probes, frequencies of HLA-DRB1, B3, B4, DQA1, DQB1 and DPB1 alleles were identified in 47 Caucasian MG patients and 105 healthy controls. None of the HLA class II alleles identified, was significantly increased in the group of patients compared to controls. However, further analysis of DQA1-DQB1 genotype demonstrated that susceptibility to the disease is associated with two trans DQ alpha beta heterodimers encoded by DQA1*01-DQB1*0201 or DQA1*01-DQB1*0301 combinations (72% in patients vs 29% in controls, RR = 6.2, Pc < 0.001). DQA1*01 group of alleles (DQA1*0101, 0102 or 0103 allele) encode DQ alpha chains sharing long polymorphic sequence including non-charged glycine and positively charged arginine residues at positions 55 and 64, respectively. DQB1*0301 and DQB1*0201 encode a DQ beta chain bearing a negatively charged glutamic acid at position 45 and 46, respectively. A combination of such DQ alpha and DQ beta chains may form susceptibility peptide-binding groove. In MG patients with thymic hyperplasia an additional association with DQA1*0501 in linkage disequilibrium with DQB1*0201 and DQB1*0301 alleles was observed (RR = 17.2, Pc < 0.001). Our data indicate that MG, like other autoimmune diseases, is associated with particular HLA-DQ alpha beta heterodimers, independently of clinical parameters. A role for DQA1*0501 allele in the manifestation of thymic hyperplasia disorders is suggested.
The effect of plasma exchange (PE) in the Guillain-Barré syndrome (GBS) has been evaluated in 4 randomized clinical trials. A positive effect could be excluded in only one study conducted in Great Britain which included 29 patients. The more powerful studies conducted in Sweden (39 patients), in North America (245 patients) and in France (220 patients) demonstrated that early use of four PEs in patients with a GBS severe enough to require assistance in walking was followed by decreased duration and severity of the acute phase. These conclusions were ratified at a North American consensus conference. More recently, PE has been demonstrated to increase the number of patients who recover normal muscular power after a 1-year follow-up. The French trial also demonstrated that diluted albumin should be preferred over fresh frozen plasma. The number of plasma exchanges and the role of PE in initially benign forms is of great importance and is now under study by a cooperative group in France. The effect of immunoglobulins (IgG) was recently investigated in a randomized trial including 150 patients. In this study, high doses (0.4 g/kg/day for 5 days) were compared with 5 PE administered between days 7 and 14 in children and adults who, at inclusion, were unable to walk. The main result was that the outcome at one month was good with IgG as with PE. Treatment is easier with IgG, and morbidity is lower. Direct costs are similar. If IgG are shown to be as effective as PE, IgG should be given for GBS.(ABSTRACT TRUNCATED AT 250 WORDS)
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Twenty consecutive patients (16 women and 4 men), with a mean age of 40 years, who were diagnosed and treated for myasthenia gravis were enrolled in a prospective investigation aimed at determining the amount of respiratory disturbance occurring during sleep while they received treatment. Patients were clinically evaluated to determine body mass index, presence of upper airway anatomical abnormalities, level of functional capacity and activity scored from 1 to 5, and presence of sleep-related complaints. They underwent daytime pulmonary function tests, determination of maximal static inspiratory pressure, measurement of transdiaphragmatic pressure, and measurement of arterial blood gas levels. Polygraphic monitoring during sleep, evaluating respiration and oxygen saturation, was also performed. Results indicated that in the studied population, all subjects had evidence of daytime diaphragmatic weakness as demonstrated by transdiaphragmatic pressure measurements, independent of the degree of autonomy and functional capacity and activity level reached. Older patients with moderately increased body mass index, abnormal total lung capacity, and abnormal daytime blood gas concentrations were the primary candidates for development of diaphragmatic sleep apneas and hypopneas, and oxygen desaturation of less than 90% during sleep. However, these clear indicators were not found in all subjects with sleep-related disordered breathing. Rapid-eye-movement sleep was the time of highest breathing vulnerability during sleep. Sleep-related complaints may also help identify subjects at risk for abnormal breathing during sleep, even when daytime functional activity is judged normal.
Ten cases of postanoxic coma have been studied. A clinical neurological examination with study of brainstem reflexes and the EEG recording were made on the first day (J1), the third day (J3) and the tenth day (J10) after the start of the coma. A recording of the visual evoked potentials, the brainstem evoked potentials and the somatosensory potentials combined was made at the same time. A clinical examination is carried out one month after the coma when the patient survives. According to the initial clinical examination, we distinguished 3 groups of subjects. The results show that in group III the visual evoked potentials such as EEG have a slightly significant prognostic value; frequently the near outcome lead to death whereas EEG activity persists and the visual evoked potentials disappear later. On the other hand, the association of brainstem evoked potentials and somatosensory potentials clearly has a higher prognostic value in this group. The disappearance of the shortest brainstem responses and the cortical somatosensory responses is clearly an unfavourable prognosis. This disappearance associated with the end EEG activity is the absolute proof of brain death. On the other hand, the persistence of these responses is of a better prognosis at least on the survival level, but their degradation during evolution is unfavourable.
Methotrexate toxicity is rare but extremely severe. When complete, it consists of ulcerations of the gastrointestinal mucosae responsible for necrotizing enteritis, erythroderma, bone marrow aplasia, interstitial pneumonia, hepatitis and organic renal failure with diuresis. Toxicity is facilitated by pre-existing renal impairment, third sector and abstention or underdosage of foliculinic acid prescribed as antagonist. The diagnosis rests on serum assays, the results of which must be interpreted taking into account the assay method and the time elapsed between the injection of methotrexate and its assay in serum. The multivisceral pathology observed may totally regress, as in the case reported here. Treatment is based on symptomatic measures, starting with maintenance of an abundant and alkaline diuresis, and on the parenteral administration of folinic acid in doses that vary with the authors.
Clinical improvement has been observed in myasthenia gravis patients treated by intravenous immunoglobulin (IVIg). In order to investigate the mechanism of action of these IVIg, we looked for an in vitro interaction between IVIg and the anti-acetylcholine receptor autoantibodies. Significant inhibition by IVIg of anti-acetylcholine receptor autoantibody activity from 30 MG sera was observed and binding of anti-acetylcholine receptor autoantibodies on IVIg was found for four of five myasthenia gravis sera. These observations suggest that IVIg contains Ig directly binding to and inhibiting pathogenic autoantibodies.
Modalities of oxygen therapy for pregnant women intoxicated with carbon monoxide (CO) are ill defined. Hyperbaric oxygen (HBO) is presumed to be hazardous to the pregnancy. On the other hand CO entails anoxic injuries in the mother and fetus. We have entered 44 pregnant women who sustained an acute carbon monoxide poisoning at home, into a prospective study in order to assess HBO tolerance. They were treated within 5.3 +/- 3.7 h (range: 1-12) of the intoxication with a combination of 2 h of HBO at a pressure of 2 atmospheres absolute (ATA) and 4 h of normobaric oxygen, irrespective of the clinical severity of the intoxication and of the age of pregnancy. Six patients were lost to obstetric follow-up. Only 2 patients sustained a spontaneous abortion: 1 within 12 h and 1 within 15 days of the intoxication. Thirty-four women gave birth to normal newborns. Finally 1 elected to undergo abortion for reasons unrelated to the intoxication and 1 gave birth to a baby with Down's syndrome. There is no evidence that HBO was involved with either abortion of our study. We conclude that HBO may be carried out in pregnant women acutely intoxicated with carbon monoxide.
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