Distribution of juxtaglomerular cells and synthesis and release of renin granules in patients with renal artery stenosis

100 pieces of renal tissue from 4 patients with renal artery stenosis were studied histologically. Juxtaglomerular cells were found not only in the region close to the glomerulus but also in the proximal 2/3 of the afferent arteriole of the glomerulus, but not in the interlobular arterioles. In the cytoplasm of juxtaglomerular cells, three kinds of granules were found: crystalline granules (immature), the round or ovoid granules (mature), and the lobulated granules (fusion). Renin was synthesized in the rough endoplasmic reticulum and packaged in the Golgi complex. Electron microscopic findings suggested that the secretory microvesicles were produced on the surface of Golgi complex. They fused to form primary crystalline granules, which were enlarged by renin supplied by transportation vesicles and finally formed typical crystalline granules. The mature renin granules (round or ovoid) moved toward the periphery of the cytoplasma. Their limiting membranes on the side toward the basement membrane disintegrated and formed microvesicular bodies passing through the periplasm, and the basement membrane and were discharged into the interstitial matrix.

DNA probe technique for diagnosis of human cytomegalovirus infection

A rapid diagnostic assay for human cytomegalovirus (HCMV) has been developed for detecting HCMV DNA in urine samples with 32P-labelled cloned fragment, Eco RI fragment B, of DNA from HCMV strain Towne. 3.2 pg of homologous fragment from HCMV DNA could be detected by the labelled probe, and it did not hybridize DNA from other herpes viruses or human cells in dot hybridization assay. The assay correctly identified all (100%) of 7 coded urine specimen cultures positive for HCMV and 9 (90%) of 10 urine sample cultures negative for HCMV. So the hybridization assay was correct and as sensitive as the currently available tissue culture technique. The infection levels of different populations, such as organ transplantation recipients, patients with infantile hepatitis syndrome, normal infants, fetuses, have been investigated by the hybridization assay in the present study.

Laboratory and clinical diagnosis of human cytomegalovirus infection after transplantation

Urine and blood specimens from 32 recipients of allograft organ transplant were investigated for human cytomegalovirus (HCMV) by conventional cell culture, indirect immunofluorescent assay subsequent to the rapid cell culture and DNA-DNA hybridization. The results showed that the rapid cell culture technique might be the best method for rapid detection of active HCMV infection after transplantation because it possesses the advantages of simplicity, speediness, sensitiveness, and high reliability of detecting productive HCMV infection. The major symptoms were prolonged or intermittent fever unresponsive to antibiotics, dysfunction or loss of function of the transplanted organ, pulmonary infiltrates and leukopenia. As our results suggested, reactivation of a latent infection appears to be the most probable etiologic factor contributing to HCMV infection after transplantation.

Coronavirus: how a large RNA viral genome is replicated and transcribed

Coronaviruses are important human and animal pathogens and contain an extraordinarily long (27-31 kb) RNA genome. Its RNA synthesis involves complex mechanisms of regulation, similar to those of DNA viruses. In this treatise, mouse hepatitis virus (MHV) is used as a model for the discussion of the mechanism of viral RNA synthesis. We show that MHV RNA synthesis requires interactions of multiple RNA components, which are likely mediated by protein-RNA and protein-protein, as well as RNA-RNA, interactions. This virus also provides a unique example of a discontinuous transcription mechanism, which involves a trans-acting RNA component. Finally, study of the cis-acting signals for the various steps of RNA synthesis revealed an insight into the regulation of viral RNA synthesis. This discussion suggests that the regulation of RNA synthesis in coronavirus is more complex than previously thought possible for RNA viruses. Coronavirus RNA transcription and replication may serve as a paradigm of RNA synthesis for RNA viruses in general.

[Study on chromosomal centromeric dots in couples with spontaneous abortion]

Chromosomal centromeric dots (Cd) of peripheral blood in 20 couples with spontaneous abortion and 10 normal couples were studied by Cd-banding technique. The frequencies of Cd loss and centromeric dots-nucleolar organizer region (Cd-NOR) fusion were 0.36 +/- 0.15/cell and 0.31 +/- 0.20/cell in the couples with abortion, 0.22 +/- 0.13/cell and 0.20 +/- 0.19/cell in normal couples respectively. These results showed that frequencies of Cd loss and Cd-NOR fusion in couples of spontaneous abortion were significantly higher than those in the normal couples. We suggested that the occurrence of spontaneous abortion in human might casually relate to the changes of Cd.

[An epidemiological study of knee osteoarthritis]

2,063 adult people of a Beijing suburban village were surveyed for osteoarthritis of the knees. Questionnaire was completed in all. 799 (38.7%) responded to have knee joint pain. 311 with knee joint pain and 212 without knee joint pain were selected randomly for X-ray films of the knees. In the former group, 79 showed osteoarthritic X-ray changes and were thus diagnosed as such, accounting 24.7% of those with knee pain. In the latter group, all were not diagnosed as clinical osteoarthritis, yet 54 (25.5%) showed also X-ray osteoarthritic changes. In both groups the X-ray osteoarthritic changes increased in parallel with increase of age, reaching 78% in those aged 60 and more in the former group and 67% in the latter group. 100 retired cadres were similarly surveyed but all had X-ray films of the knees taken. 51 of 100 responded knee pain, out of whom 49 (95.9%) showed X-ray osteoarthritic changes and were thus diagnosed as such. The overall prevalence rate of osteoarthritis of knee in rural population as judged by the 523 who had taken X-ray films (people with and without knee pain are not entirely proportional) is about 9.6% and that of 100 aged retired cadres is 49%. Those with X-ray knee osteoarthritic changes but without knee pain were not categorized as clinical osteoarthritic cases.

Transfection of NG108-15 cells with antisense opioid-binding cell adhesion molecule cDNA alters opioid receptor-G-protein interaction

We previously reported that transfection of antisense OBCAM (opioid-binding cell adhesion molecule) cDNA into NG108-15 neuroblastoma x glioma hybrid cells, which contain delta-opioid receptors, results in greatly reduced opioid binding (Ann, D. K., Hasegawa, J., Ko, J. L., Chen, S. T., Lee, N. M., and Loh, H. H. (1992) J. Biol. Chem. 267, 7921-7926. Here we report that these cells show altered coupling between opioid receptors and G-proteins. G-proteins were identified using cholera toxin (CTX)-induced ADP-ribosylation and antisera selective for Gi2 and Go alpha subunits. In the presence of delta-opioid agonists, CTX induced the incorporation of [32P]ADP-ribose into a 39-41-kDa protein with the same electrophoretic mobility as Gi2 and Go alpha subunits. This band, which was also a pertussis toxin (PTX) substrate, exhibited decreased CTX-induced ADP-ribosylation in membranes of cells treated chronically with D-Ala2-D-Leu5-enkephalin (DADLE). In cells transfected with antisense cDNA for OBCAM, labeling of this band was also decreased, compared with either sense-transfected or untransfected cells. DADLE inhibition of adenylyl cyclase and DADLE stimulation of GTPase were also greatly impaired in antisense cells, as well as GTP and GppNHp inhibition of basal and forskolin-stimulated adenylyl cyclase. These results provide further evidence for a role of OBCAM in opioid receptor function.

Lipoprotein(a), plasmin modulation, and atherogenesis

Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein however the mechanisms by which Lp(a) promote the atherosclerotic process are not clear. The apolipoprotein(a) portion of Lp(a) shares partial homology with plasminogen, a finding that has stimulated numerous studies. Lp(a) binds to fibrin and the affinity between fibrin surfaces and Lp(a) appears to be related to the state of oxidation of the lipoprotein particle. Lp(a) also effects fibrin-dependent plasminogen activation. Recent findings suggest that dependent plasminogen activation. Recent findings suggest that depending upon the in vitro conditions, Lp(a) either promotes or inhibits plasmin formation. Lp(a) also inhibits cell-surface dependent plasmin generation that is associated with an inhibition of transforming growth factor-beta (TGF-beta) production in cell coculture systems. Lp(a) stimulates smooth muscle cell migration and proliferation as a secondary response to this decrease in TGF-beta concentration. Studies in transgenic mice containing the human apolipoprotein(a) gene, document that both plasmin and TGF-beta formation in the media of the aorta is markedly decreased in the presence of apo(a). Thus the atherogenicity of Lp(a) may be mediated, in part, through its modulation of plasmin and TGF-beta production in the blood vessel wall.

Simultaneous activation of Ig and Oct-2 synthesis and reduction of surface MHC class II expression by IL-6

Terminal differentiation of B cells to plasma cells in vivo is characterized by secretion of Ig and extinction of MHC class II expression on the cell surface. We show that IL-6 signaling leads to marked increases in the synthesis and secretion of Ig in clonal human B cell lines and newly isolated polyclonal B lymphocytes in vitro. The IL-6-induced cells resemble plasma cells in ultrastructure and in reduced expression of surface MHC class II. Enhanced Ig synthesis is a result of coordinated transcriptional activation of Ig genes without promoter or isotype specificity, and differential accumulation of the mRNA encoding the secreted form of Ig heavy chain. It is saturable and subject to negative control when IL-6 stimulation is prolonged. Coordinate with temporal changes in Ig synthesis, the DNA-binding activity and the synthesis of the B cell-enriched transcription factor Oct-2 are regulated. Thus, differentiation of B cells with IL-6 in vitro recapitulates the hallmarks of terminal B differentiation in vivo; Oct-2 may have a role in this process.