Expression of transforming growth factor-beta s and their receptors by human retinal glial cells.

PURPOSE: To help test the hypothesis that transforming growth factor beta (TGF-beta) may serve an autocrine function in the retina, we asked whether human Müller (glial) cells in culture express TGF-beta receptors, contain transcripts for various isoforms of this cytokine, and release TGF-beta s into the medium. METHODS: Using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique with specific primers for TGF-beta 1, -beta 2 and -beta 3 precursors and for TGF-beta type I and type II receptors, we searched for mRNA transcripts expressed by cultured human Müller cells. Also, an ELISA assay allowed quantification of the levels of various TGF-beta s in medium exposed to these glial cells. RESULTS: Human Müller cells in culture express transcripts for both type I and type II TGF-beta receptors and also for TGF-beta 1 and TGF-beta 2. In conditioned medium, the concentration of TGF-beta 1 in the mature form was below detectable levels, and the total TGF-beta 1 was relatively low (mean = 252 pg/ml in confluent cultures). In contrast, the mean levels of mature (55 pg/ml) and total (2530 pg/ml) TGF-beta 2 were markedly higher. CONCLUSIONS: Our observations that cultured Müller cells contain mRNA coding for the TGF-beta 2 precursor, release TGF-beta 2 into the medium and express transcripts for both type I and type II TGF-beta receptors are consistent with the idea that this cytokine serves an autocrine function for these glia in the retina.

[Measurements of hydrogen sulfide held in water and sludge in sewerage holes and the required amount of ventilation].

In Japan, it is required to measure the hydrogen sulfide (H2S) concentration before sewerage work can commence, in order to prevent toxic accidents caused by H2S. The actual H2S concentration of the sewerage hole is often different from that initially measured, and there is often a more than fatal concentration because of rapidly volatilizing H2S. However, no countermeasures for this have been developed, nor has any system for the measurement of the H2S held in sewerage water and sludge been established yet. In this paper, therefore, the measurement of H2S dissolved in water was investigated, and the actual form of the H2S held in the water and the sludge was analyzed. Prevention measures against toxic accidents were also investigated. Water and sludge were collected from an actual sewerage hole, and the quantities of H2S held in them were measured by the new method with the stripping which we developed. We also determined the quantity of H2S volatilized from the water surface during work, and estimated the change of air quantity necessary to reduce the concentration of H2S to a safety level for workers. As a result, it was shown that even if the H2S concentration of the gas phase before the work is regarded as at a safety level for workers, they may be in an extremely dangerous situation resulting from the rapid volatilization of H2S during their work.(ABSTRACT TRUNCATED AT 250 WORDS)