Identification of an alveolar type I epithelial cell-specific DNA nuclear import sequence for gene delivery.

The ability to restrict gene delivery and expression to particular cell types is of paramount importance for many types of gene therapy, especially in the lung. The alveolar epithelial type I (ATI) cell, in particular, is an attractive cell type to target, as it comprises 95% of the internal surface area of the lung. We demonstrate, through microinjection of fluorescently labeled plasmids, that a DNA sequence within the rat T1α promoter was able to mediate ATI cell-specific plasmid DNA nuclear import due to the binding of ATI-enriched transcription factors. Promoter deletion analysis and site-directed mutagenesis of specific transcription-factor-binding sites within the +101 to -200 bp region of the T1α promoter identified HNF3 and TTF-1 as critical transcription factors for import. To test for nuclear import in vivo, plasmids expressing GFP from the CMV promoter were delivered into the lungs of mice by electroporation and evaluated immunohistochemically 48 h later. Plasmids carrying the 1.3 kbp T1α sequence resulted in GFP expression almost exclusively in ATI cells. This represents a new and highly efficient way to target a specific lung epithelial cell type both in vitro and in vivo based on the restriction of DNA nuclear import.

Factitious disorders in a teaching hospital.

To obtain an overview of factitious disorders in hospitalized patients we surveyed the cases found in our hospital during a 10-year period. Forty-one disorders were identified including one that was fatal and others that were chronic, severe, and life-threatening. The disorders fell into four subgroups: self-induced infections, simulated illnesses, chronic wounds, and surreptitious self-medication. These subgroups had implications for prognosis and management. The patients included 39 women and 2 men, average age 33 years, 28 working in medical jobs. With three possible exceptions, none of the patients had Munchausen's syndrome and were not malingerers or sociopaths. Most of these patients were immature, passive, and hypochondriacal; none had major mental disorders. Thirty-three patients were confronted with evidence that their disorders were self-induced; none signed out of the hospital or became suicidal. Although only 13 patients acknowledged causing their disorders, most improved after confrontation and 4 of the most chronic became asymptomatic. The cases differed from commonly held assumptions about factitious disorders.

Amino acid transport in Mycoplasma.

The uptake of l-histidine by Mycoplasma fermentans and l-methionine by M. hominis was found to be dependent on temperature and pH and to follow saturation kinetics. Several metabolic inhibitors inhibited this uptake. The transport system for l-methionine was highly specific. The l-histidine transport system was less specific, and the uptake was competitively inhibited by l-arginine and l-lysine. l-Histidine accumulated in the intracellular pool of M. fermentans at a concentration about 200 times that found in the medium. Efflux of accumulated l-histidine was demonstrated at 37 C, but not at 0 C. The rate of efflux was greatly accelerated by addition of l-histidine to the medium. The findings indicate that the Mycoplasma cell membrane contains specific transport systems resembling the permease systems of other microorganisms.

Candidal vaginitis in hormone-treated mice: prevention by a chitin extract.

In view of findings from previous studies that a chitin soluble extract (CSE) blocked adhesion of Candida albicans in vitro and in vivo and prevented thereby a short lived candidal infection in naive mice, we attempted in the present study to block by CSE the development of a persistent infection, induced in hormone-treated animals. Continuous oestrus phase was obtained in mice by repeated weekly subcutaneous injections with estradiol benzoate. Intravaginal inoculation of the hormone-treated mice with 10(7)-10(10) C. albicans cells induced a persistent candidal infection. Fifty three mice were pretreated intravaginally prior to inoculation of C. albicans with 2.5, 5.0 or 10 mg/mouse of a CSE cream and followed up for development of infection in comparison to 30 untreated animals. Twenty four hrs post fungus inoculation the infection rate among the CSE treated mice was 11-23% VS 84% among the controls; the rate increased a week later to 97% among the controls VS 41-50% among the CSE treated. Administering the CSE to the mice prior--and post-yeast inoculation (37 mice), led to increased efficacy of the treatment. The data, indicating that CSE is an effective measure for preventing persistent candidal vaginitis, may open the way to consider a similar approach for prophylaxis of vaginitis in human susceptible populations.