Mechanism of efficient transfection of the nasal airway epithelium by hypotonic shock

The main barrier to gene transfer in the airway epithelium is the low rate of apical endocytosis limiting naked DNA uptake. Deionized water is known to stimulate the exocytosis of numerous intracellular vesicles during hypotonic cell swelling, in order to expand plasma membrane and prevent cell lysis. This is followed by the phase of regulatory volume decrease (RVD), during which the excess plasma membrane is retrieved by intensive endocytosis. Here we show that the more hypotonic the DNA solution, the higher the transfection of the nasal tissue. P2 receptors are known to be involved in RVD and we demonstrate that some P2 agonists and a P2 antagonist impair transfection in a time-dependent manner. Our study strongly suggests that the nasal airway epithelial cells take up plasmid DNA in deionized water during RVD, within approximately half an hour. Our simple gene delivery system may constitute a promising method for respiratory tract gene therapy.

Prevalence of drug-induced electrocardiographic pattern of the Brugada syndrome in a healthy population

To determine the prevalence of drug-induced Brugada's syndrome (BrS) electrocardiograms (ECGs) in a healthy population, a sodium channel blockade challenge was performed in previously identified subjects with BrS-compatible (BrC) ECGs. These subjects were detected in 1,000 normal patients in whom first ECGs were systematically recorded. Because of the intermittent nature of electrocardiographic modifications in BrS, second ECGs were also recorded in a representative sample of the population presenting with first ECGs with normal results. The prevalence of typical drug-induced BrS ECGs was 5 of the 1,000 patients. This value was fivefold greater than the reported prevalence of spontaneous BrS ECGs in the healthy population.

[Contribution of the counter-immunoelectrophoresis for the diagnosis of pneumococcal infections (author's transl)]

Using counter-immunoelectrophoresis (CIE), the authors have looked for pneumococcal antigens in biological fluids in 141 pneumococcal infections cases (70 meningitis, 25 empyema, 40 pneumonia, 5 peritonitis, 1 pericarditis). The best results (superior to bacteriological results) were obtained with CSF and pleural fluid. Testing sputum by CIE seems to have a real interest in pneumonia. CIE associated with bacteriology, gives more than 20% increase in aetiological diagnosis in pneumococcal infections and permits to set accurate aetiological diagnosis in less than two hours.

[The detection of bacterial antigens by counter-immunoelectrophoresis in N. meningitidis, H. influenzae serotype b, S. pneumoniae infections. Diagnostic value and evolutive aspect (in 216 cases) (author's transl)]

Using counterimmunoelectrophoresis (CIE) the authors have assayed for soluble bacterial S. pneumoniae, N meningitidis group A, B, C. H. influenzae type b antigens, biological fluids in 216 patients (meningitis: 136; pneumonia: 76; miscellaneous: 4) during 16 months. Because of heterogeneous recruiting (the bacteriology was carried out by different laboratories) the increase in aetiological diagnosis given by CIE is only statistically valid for the bacteriologic negative group when blind antibiotic therapy had already been given. In this group, CIE makes a notable increase in diagnosis of 22,1 % +/- 10,1 in meningitis and 25,5% +/- 12,7 in pneumonia. Various physiopathological aspects are considered concerning soluble bacterial antigens detection during the course of the disease. This method seems very useful and accurate; and therefore should be used in every microbiologic laboratory.

[Etiological diagnosis of acute pneumopathies. Evaluative study. 100 cases in a pneumologic center]

This study involved 100 patients with acute pneumonia and hospitalised in a specialised service: 12 bacterial pneumonia, 40 viral pneumonia (i.e. 52% of the total). Only precise viral and bactérial studies could improve these results. Given the poor results obtained using the microbiological techniques available here, the authors suggest the inclusion in all subsequent studies of aetiological diagnosis of a quantitative examination of sputum bacterial flora and examination for the detection of bacterial exoantigens.