We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure on day 10 than on day 30. Because the change of lung tissue elasticity evaluated from the saline-filled pressure-volume curve was equal for the 2 days, the higher decrease of air volume on day 10 was due primarily to contribution of alveolar surface force. Pressure differences between deflation limbs of air-filled and saline-filled pressure-volume curves, which represented net alveolar surface force, were significantly higher at any lung volume between 50 and 90% total lung capacity on day 10, but almost no significance was observed on day 30. Phospholipid concentration in bronchoalveolar lavage fluid significantly decreased on day 10 but had improved by day 30. Analysis of phospholipid species in purified lung surfactant showed decreased fractions of disaturated phosphatidylcholine and phosphatidylglycerol on day 10. Surface-active properties of the surfactant, measured by a modified Wilhelmy balance, were remarkably hampered on day 10, but most of them had improved by day 30. We consider that the quantitative and functional abnormalities of lung surfactant have a part in the aggravation of lung mechanics in the acute phase of pulmonary fibrosis.

Enterohaemorrhagic Escherichia coli O157 (O157) is infectious to humans, particularly children, at very low doses and causes not only haemorrhagic colitis but also other serious symptoms. To investigate an association between intestinal bacterial flora and resistance to such infections, we screened faecal samples for the presence of enteric bacteria that are able to suppress the growth of O157. Samples from 303 individuals, 35 children (aged < or =6 years) and 268 adults (aged 20-59 years), were examined. Colonies with different appearances on sorbitol MacConkey agar medium were screened for the production of bacteriocins inhibitory for O157 in an overlay agar plate assay. O157-inhibiting strains were isolated from 52 individuals. The prevalence of these bacteria tended to rise with age, and was significantly higher among 40- to 59-year-old adults (23/101, 22.8%) than among children (3/35, 8.6%; P<0.05). To test the hypothesis that these bacteriocin-producing strains contribute to resistance against O157 in human adults, we examined faecal samples of 25 healthy O157 carriers. Inhibitory bacteria were more prevalent among the latter (9/25, 36.0%) than among age-matched subjects who did not carry O157 (49/268, 18.3%). It appears, therefore, that inhibitory bacteria in the human gut may play a role in inhibiting propagation of O157 and/or suppressing expression of virulence factors by this pathogen.

To evaluate antibody responses against lipopolysaccharide (LPS: O157, O26, and O111) in enterohemorrhagic Escherichia coli (EHEC) infection, sera of 24 schoolchildren associated with the Morioka outbreak in 1997 and of 74 sporadic patients suspected of having EHEC infection were examined. Using a positive standard serum, quantitative evaluation of LPS antibodies by an enzyme‐linked immunosorbent assay (ELISA) was established. High levels of specific IgM and IgA antibodies against homologous E. coli LPS were present in the acute period and are characteristic of EHEC. This could be used for the serological diagnosis of EHEC infection, except for early infants and the elderly. In addition to the specific homologous response, multiple antibody responses against different serotypes other than those isolated were demonstrated in many cases by qualitative analysis using Western blotting.

A 65-year-old man was admitted to our hospital because of dyspnea on exertion. He had oculocutaneous albinism innately and his parents were consanguineous. His chest roentgenogram on admission showed reticulonodular infiltrates and cystic changes throughout both lung fields, and 7 cm mass in the left middle field.

Metachromatic leukodystrophy (MLD) is an autosomal recessive, inherited, lysosomal storage disease caused by a deficiency in arylsulfatase A (ASA). This disease is characterized by progressive demyelination leading to severe neurological symptoms. Allogenic bone marrow transplantation at an early stage of clinical course is only effective treatment currently available. Accordingly the corrective transfer of the ASA gene into hematopoietic stem cells is thought to be an important option for curative treatment for MLD. We have recently developed a selectable vector system based on ex vivo sorting of transduced cells (Migita et al. 1995). In this study, we applied this selectable system for development of MLD gene therapy. A bicistronic retroviral vector containing ASA cDNA and CD24 cDNA as a selectable marker gene was constructed. This vector was successfully transduced on fibroblasts from MLD patients, ASA activity was increased 7-fold compared to normal untransduced cells. PCR Southern analysis of hematopoietic colonies showed that transduction efficiency of CD34+ cells was 11-22%. However, after fluorescenceactivated cell sorting using anti-CD24 antibody, 75-100% of colonies became vector positive. The sorting raised the ASA activity several fold compared to untransduced CD34+ progenitors. These results suggest that a bicistronic ASA vector containing a CD24 selectable marker could be a useful component of gene therapy for MLD.