Ann Soumillion

Human urinary protein 1: evidence for identity with the Clara cell protein and occurrence in respiratory tract and urogenital secretions.

Protein 1 (P1), a low mol mass urinary protein of unknown function, has been purified, sequenced and quantified in human biological fluids. The molecular size, subunit composition and partial amino acid sequence of P1 are similar to those of the 10 kDa Clara cell protein (CC10), a lung secretory protein. P1 is found in high concentrations in sputum, bronchoalveolar lavages, urine and semen of healthy individuals and in urine of some pregnant women. Contrary to what is claimed, P1 or CC10 is not a specific and unique product of the lung, but like its homologue in rabbits (uteroglobulin) it is also present in urogenital secretions. P1 or CC10 may act as a natural immunosuppressor protecting the respiratory and urogenital tracts from unwanted inflammatory reactions.

Metallothioneins in Human Kidneys and Associated Tumors

Human kidneys and their associated tumors (nonneoplastic kidney tissues from patients with a transitional cell carcinoma or an adenocarcinoma and the adenocarcinomas themselves) were evaluated for their Zn, Cd, and Cu contents as well as for their metallothionein (MT) level. The total Cd content was correlated with the MT content, and both values were significantly decreased in the adenocarcinomas in comparison with the other tissues. After extraction and separation by anion-exchange chromatography, MT-0 was identified in the nonneoplastic tissues from both the adenocarcinomas as well as the transitional cell carcinomas. Since until now MT-0 protein was only found in human fetal liver and in Zn-stimulated human monocytes, a possible role for this isoform as an oncofetal marker is hypothesized. Separation of the isoforms of MT by reversed-phase high-performance liquid chromatography and sequence analysis showed besides MT-1e and MT-1l the isoform-MT-1g, which is not expressed in the healthy kidney, and MT-1k, an isoform which is not yet demonstrated in renal tissues. We conclude that the expression profile of the MT isoforms in the kidney changes due to the presence of a tumor.

Hepatitis B virus infection in microcarrier‐attached immortalized human hepatocytes cultured in molecularporous membrane bags: a model for long‐term episomal replication of HBV

Studies on the pathobiology of chronic (long‐term) hepatitis B virus (HBV) infection and in vitro drug testing have been hampered by the lack of appropriate systems for culturing susceptible cells chronically infected with HBV. Most of the in vitro studies of HBV replication have been performed with HBV genome‐transduced cell lines. In this system, viral production is mainly the result of chromosomal replication. In an invitro infection system, owing to medium refreshment (which leads to the removal of infectious particles necessary for the perpetuation of infection) and to trypsinization for cell passages, it is difficult, if not impossible, to maintain chronic HBV infection, despite the use of susceptible cells. To circumvent these unfavourable factors for chronic HBV infection in vitro, we cultured microcarrier‐attached immortalized human hepatocytes, infected with HBV, in molecularporous (MW 12000–14000) membrane (dialysis) bags for a duration of 2 months. HBV covalently‐closed‐circular (ccc) DNA, HBV precore/core and X mRNAs were detected in the cells cultured in this system following infection until the end of the experiment (day 58), while in classical culture conditions (monolayer), markers of HBV replication were also detected. Production of hepatitis B surface antigen (HBsAg) and HBV DNA was detected and their levels in culture medium (collected at the end of experiments from the molecularporous membrane bags) were increased 2.86‐ and 3.28‐fold respectively. Using Southern blot analysis, HBV replicative intermediates could also be demonstrated throughout the experiments. However, integrated HBV DNA was not present. In contrast, HBV ccc DNA, HBV precore/core and X mRNAs, and replicative intermediates were not demonstrable in FTO 2B rat hepatoma cells infected in the same manner in parallel experiments. This in vitro infection system, using susceptible, immortalized human hepatocytes, therefore provides a new tool for studying the long‐term effect of HBV infection, mainly involving episomal replication in hepatocytes, and for drug testing.