[Reaction of 3-hydroxy-dihydrosantonin with TsOH. A formal synthesis of dihydrocotunolide]

In connection with our another project a relatively large quantity of 5 was required. We, therefore, investigated the reaction of 3 with TsOH; this gave a diene mixture 7a, 7b, 6 and 5 in a ratio of 8:2:4:1. Almost the same 8:2:1 "equilibrium mixture" of the dienes 7a, 7b and 5 was also obtained when the purified samples of 5 and 7a were independently treated with TsOH under the same conditions. The above results suggest that the dienes might be produced in the following way; beta-elimination of H2O from 3 gives a homoannular diene 5. The protonation to the more electron-rich tetrasubstituted C4-C5 double bond of 5 from the less hindered alpha-side followed by the isomerization of the double bond gives 7a. 7b is formed via 7a and/or 5 by the double bond isomerizations. On the other hand, 6 is formed by concerted elimination of H2O between C3-OH and C6-H. As a result of these studies, the synthetic precursor of dihydrocostunolide 7b which was already prepared by Corey in 6 steps (ca. 7%) from santonin was synthesized in 3 steps (ca. 6%) from the latter.

Effect of ketanserin on 5-hydroxytryptamine-induced constriction in isolated, perfused canine basilar arteries exposed to blood

The blocking effect of ketanserin, a 5-hydroxytryptamine (5-HT)2 receptor antagonist, was examined on responses to intra-luminal 5-HT or potassium chloride (KCl) in isolated and perfused canine basilar arteries before and after extraluminal whole blood by means of the stainless-steel cannula inserting method. Four hours after the application of blood, the constriction to 5-HT was significantly enhanced, while that to KCl was significantly attenuated. The absolute value in the decrease of perfusion pressure for the 5-HT-induced constriction sensitive to ketanserin was much greater after the blood application than that before the application. It is suggested that the augmentation of cerebrovascular responses to 5-HT in the early stage immediately after subarachnoid haemorrhage (SAH) might be mediated by 5-HT2 receptors at least in part. This early constrictor mechanism may be implicated in the aetiology of the following late stage of cerebral vasospasm after SAH.

Telomerase as a tool for the differential diagnosis of human hepatocellular carcinoma

BACKGROUND

Telomerase activation is thought to be essential for the immortality of cancer cells. We measured telomerase activity in human liver samples, including hepatocellular carcinoma (HCC), and evaluated this assay as a tool for the diagnosis of HCC using 21-gauge (21-G)-needle biopsy specimens.

METHODS

Ninety-four liver samples (27 HCC, 27 liver cirrhosis, 37 chronic hepatitis, and 3 normal liver) that were surgically resected or biopsied with a 12-gauge Silverman needle and 13 HCC samples that were biopsied with a 21-G needle were analyzed for telomerase activation.

RESULTS

Eleven of 29 (38%) tumor-bearing liver samples were weakly telomerase-positive, whereas telomerase activity was observed infrequently in nontumor-bearing liver samples (6 of 35; 17%) and in normal liver samples (0 of 3; 0%). The positivity of surgical samples for well differentiated, moderately differentiated, and poorly differentiated HCC was 88% (7 of 8), 87% (13 of 15), and 0% (0 of 2), respectively. In telomerase-positive HCC, 43% (3 of 7) of well differentiated samples were weakly positive, whereas 92% (12 of 13) of moderately differentiated samples were strongly positive. The difference in the tumor sizes and viral marker status did not affect the activity. The telomerase activity of the 21-G-needle biopsied specimens showed no significant difference from that of the surgical samples. The positive incidence of 21-G specimens was 80% (8 of 10) and 100% (2 of 2) in well differentiated HCC and moderately differentiated HCC, respectively.

CONCLUSIONS

An incremental positivity of telomerase was observed during hepatocarcinogenesis. The use of this assay in 21-G-needle biopsy specimens may be useful in clinical examination.

Potentiation of antitumor and antimetastatic activities of adriamycin by a novel N-alkylated dihydropyridine, AC394, and its enantiomers in colon cancer-bearing mice

PURPOSE

We have previously shown that a series of N-alkylated 1,4-dihydropyridines potentiate the therapeutic efficacy of vincristine in vincristine-resistant P388 leukemia. The purpose of this study was to investigate the ability of one of the compounds, AC394, and its enantiomers to potentiate the antitumor activity of adriamycin against colon cancer cells in vitro and in vivo.

METHODS

The effects of AC394 on potentiation of adriamycin cytotoxicity and enhancement of its accumulation were evaluated using colon 26, HCT-15 and MCF-7 cells. Furthermore, the activities of AC394 and its enantiomers were compared. We also studied the combined effects of (+)-AC394 and adriamycin on subcutaneously (s.c.)-implanted and liver metastasis tumor models.

RESULTS

AC394 potentiated the cytotoxicity of adriamycin and enhanced its accumulation in colon cancer cells (colon 26 and HCT-15), which are known to express P-GP (P-glycoprotein) intrinsically. Enhancement of adriamycin accumulation by AC394 was found in s.c.-implanted colon 26 cells in vivo. Although both enantiomers of AC394 showed equal activity in vitro, (+)-AC394 was more effective than (-)-AC394 given orally. (-)-AC394 was found to be cleared more rapidly from the plasma than (+)-AC394. Thus, (+)-AC394 was evaluated for further study. Administration of (+)-AC394 significantly potentiated the antitumor activities of adriamycin in human colon cancer HCT-15 cells implanted s.c. Furthermore, in the liver metastasis model using colon 26 cells, a model completely resistant to adriamycin, the combination therapy of adriamycin with (+)-AC394 produced superior antitumor effects over adriamycin alone.

CONCLUSIONS

A newly synthesized N-alkylated 1,4-dihydropyridine derivative, (+)-AC394, showed superior effects on the potentiation of adriamycin antitumor and antimetastatic activities in vivo. These results suggest that this combination may have therapeutic efficacy not only against primary colon cancers but also against metastatic liver cancer.

Mucha-Habermann disease and its febrile ulceronecrotic variant

In 1916 Mucha and in 1925 Habermann reported an acute form of pityriasis lichenoides characterized by the abrupt onset of papulovesicular eruptions and gave the name, pityriasis lichenoides et varioliformis acuta (PLEVA) or Mucha-Habermann disease (MH). In 1966, Degos reported a rare febrile ulceronecrotic variant of MH. MH occurs mainly in young adults, while febrile ulceronecrotic Mucha-Habermann's disease (FUMHD) occurs more frequently in children. The etiology of MH remains obscure, but it may be the result of a hypersensitivity reaction to an infectious agent. Although clinical and histologic features of the disease in children are similar to those of adults, more diseases need to be differentiated in pediatric patients. In addition, a number of effective therapeutic options in adults with MH are unsuitable for use in pediatric patients, to whom beginning with oral antibiotics, usually erythromycin, is recommended. A summary of previously reported fifteen cases with FUMHD, including our case, is listed.

Telomerase as a tool for the differential diagnosis of human hepatocellular carcinoma

BACKGROUND

Telomerase activation is thought to be essential for the immortality of cancer cells. We measured telomerase activity in human liver samples, including hepatocellular carcinoma (HCC), and evaluated this assay as a tool for the diagnosis of HCC using 21-gauge (21-G)-needle biopsy specimens.

METHODS

Ninety-four liver samples (27 HCC, 27 liver cirrhosis, 37 chronic hepatitis, and 3 normal liver) that were surgically resected or biopsied with a 12-gauge Silverman needle and 13 HCC samples that were biopsied with a 21-G needle were analyzed for telomerase activation.

RESULTS

Eleven of 29 (38%) tumor-bearing liver samples were weakly telomerase-positive, whereas telomerase activity was observed infrequently in nontumor-bearing liver samples (6 of 35; 17%) and in normal liver samples (0 of 3; 0%). The positivity of surgical samples for well differentiated, moderately differentiated, and poorly differentiated HCC was 88% (7 of 8), 87% (13 of 15), and 0% (0 of 2), respectively. In telomerase-positive HCC, 43% (3 of 7) of well differentiated samples were weakly positive, whereas 92% (12 of 13) of moderately differentiated samples were strongly positive. The difference in the tumor sizes and viral marker status did not affect the activity. The telomerase activity of the 21-G-needle biopsied specimens showed no significant difference from that of the surgical samples. The positive incidence of 21-G specimens was 80% (8 of 10) and 100% (2 of 2) in well differentiated HCC and moderately differentiated HCC, respectively.

CONCLUSIONS

An incremental positivity of telomerase was observed during hepatocarcinogenesis. The use of this assay in 21-G-needle biopsy specimens may be useful in clinical examination.

Epithelial cell proliferation during colonic chemical carcinogenesis in the rat

To define the significance of alterations in epithelial cell proliferation as a marker of high risk mucosa for colorectal cancer, we examined cell proliferative events in the colonic mucosa during chemical carcinogenesis using in vitro bromodeoxyuridine labelling and by analysing serial colonoscopic biopsy specimens from dimethylhydrazine (DMH)-treated rats. In both the rectum and flexure of the colon, an increased labelling index of colonic epithelial cells, an upward extension of the proliferating zone and an upward shift of the major area of DNA synthesis of epithelial cells were observed during DMH-induced colonic carcinogenesis in rats. These changes preceded the development of the colonic tumour and were observed in endoscopically normal rectal mucosa where the tumour was absent. We confirmed the altered cell proliferative events preceding the development of the tumour by examining serial colonoscopic biopsies. The results suggest that these alterations are features that identify premalignant colonic mucosa in DMH-treated rats.

Cellular distribution of transcripts for tissue inhibitor of metalloproteinases 1 and 2 in human hepatocellular carcinomas

The cellular distribution of tissue inhibitor of metalloproteinases (TIMP)-1, and TIMP-2 was studied by using in situ hybridization in surgically removed human hepatocellular carcinomas (HCCs) and cholangiocellular carcinomas (CCCs). The purpose of this study was to characterize the protein involvement of TIMPs in the development of HCCs and CCCs. All HCCs and CCCs expressed TIMPs. The distribution of transcripts for TIMPs in the tumors was mostly homogeneous. Expression of TIMP in cancer cells was more intense than that in the surrounding noncancerous liver (either, cirrhosis, chronic hepatitis, or normal), and expression of TIMP-1 was stronger than that of TIMP-2. Expression of TIMPs varied among HCC nodules, but there was no obvious association between the expression level of TIMPs and differentiation stages or invasiveness of the HCCs. Transcripts for TIMPs were clearly demonstrated in the metastatic HCC nodules in the lung. Expression of TIMP-1 CCC was strong, and small nodules of CCC were recognized in the liver. Immunohistochemical study for TIMP-1 revealed a consistent staining of the TIMP protein with the transcripts. In the peritumoral histologically normal liver, which was not infected with either hepatitis B or C virus, expression of TIMP-1 was found in various cell types, but that of TIMP-2 was weak. Expression of TIMP-1 in hepatocytes revealed clear zonal distribution. These results suggest that TIMPs may act on modulating the matrix/tumor interaction and may play an important role in growth and invasion of HCCs and CCCs. Expression of TIMP-1 can be a marker of HCC metastasis to the lung, and also that of the extent of CCC invasion. Furthermore, the consistent expression of TIMPs in many cell types of the noncancerous liver suggests some unknown functional role that must be clarified.

Extracellular matrix components in dilated cardiomyopathy. Immunohistochemical study of endomyocardial biopsy specimens

Fibrotic change is one of the characteristic features of the heart with idiopathic dilated cardiomyopathy (DCM), but the extracellular matrix components have not been fully clarified. Fibronectin, laminin, and types IV, I and III collagen staining using the avidin-biotin-peroxidase complex method was conducted to study the localization of extracellular matrix components in biopsy specimens obtained from 7 patients with DCM. Fibronectin was observed in the endomysium and perimysium, co-existent with types I and III collagen; it was also distributed nonhomogeneously in the replacement fibrotic lesions. The staining intensity in a section varied substantially from location to location. Laminin surrounded the myocytes and was distributed in the endomysium localized together with type IV collagen, but it was not found in the perimysium. Weak but positive staining was observed in replacement fibrotic lesions in 2 patients. Similarly to laminin, type IV collagen staining was observed around the myocytes and in the endomysium. It was also observed in replacement fibrotic lesions in 4 patients either with or without laminin. Type I collagen, localized together with type III collagen, was distributed in both the endomysium and perimysium. It was also distributed nonhomogeneously in the replacement fibrotic lesions. Similar staining to type I collagen was seen for type III collagen. In summary, all examined components were observed in the fibrotic lesions with no primary deficit of any examined component being demonstrated. The variability of staining intensity and positive fibronectin staining suggests that the phases of fibrotic changes differed substantially from location to location.

Novel monoclonal antibody, SO-MU1, against human gastric MUC5AC apomucin

Human gastric mucins were chemically deglycosylated with trifluoromethanesulfonic acid. A mouse monoclonal antibody (MoAb), SO-MU1, was established against the deglycosylated mucins. SO-MU1 recognized not only the deglycosylated mucins but also the native gastric mucins. Periodate treatment of the native mucins increased the SO-MU1 reactivity. Trypsin digestion abolished the antigenicity. Human gastric cDNA expression library was screened with SO-MU1 and a mucin cDNA clone was obtained. Its sequence contained the MUC5AC tandem repeat domain. We studied gastrointestinal distribution of the SO-MU1-reactive antigen immunohistochemically. Gastric surface epithelial cells and parietal cells expressed the antigen, but the glandular cells did not. The antigen was also detected in the small intestine and biliary tract but not in the colon and pancreas. In summary, (1) MoAb SO-MU1 was raised against human gastric mucins, (2) it recognized human gastric MUC5AC apomucin, and (3) the SO-MU1-reactive antigen showed characteristic distribution in the organs of endodermal origin. MoAb SO-MU1 is the first MoAb against MUC5AC.

Relationship between response to interferon therapy and detection of hepatitis C virus RNA by differential flotation centrifugation

Circulating hepatitis C virus (HCV) particles can be fractionated by means of differential flotation centrifugation. It is reported that in the bottom fraction HCV is in the form immune complexes, whereas in the top, it is free of antibodies. We evaluated the significance of circulating complex and free HCV in chronic hepatitis C, and assessed the relationship in terms of the response to interferon (IFN) therapy. We examined sera before, just after, and 1 year after administering IFN to 18 patients with chronic hepatitis C, 10 of whom responded (group CR), and 8 did not (group NR). The amounts of virus were similar between both groups before therapy. After differential flotation centrifugation with 1.063 g/ml of NaCl, the top and bottom fractions were assayed for HCV RNA. Before therapy, HCV RNA was detected in the top fraction in 1 of 10 in group CR, and in 6 of 8 in group NR (P < 0.05, chi-square test). HCV RNA was positive in the bottom fraction of all samples. In a follow-up study of group NR, HCV RNA was detected in the top fraction in 3 of 8 just after IFN therapy, and in 7 of 8 after 1 year. This study suggests that the presence of HCV in the top fraction can predict a poor response to IFN therapy.

Transient elevation of nerve growth factor content in the rat hippocampus and frontal cortex by chronic ethanol treatment

The nerve growth factor (NGF) content in the hippocampus and frontal cortex of chronic ethanol-treated rats was measured and compared with that of control rats, using a two-site enzyme immunoassay (EIA) system. The different time periods of chronic ethanol treatment caused transient elevation of the NGF content in both the hippocampus and frontal cortex. The NGF content in the hippocampus was significantly elevated in rats undergoing ethanol treatment of 2 weeks and 1 month. Nerve growth factor content of the 1 month treatment was higher than that of the 2 week treatment. However, a 3 month administration of ethanol reduced the NGF content to the control level. The NGF content in the frontal cortex increased significantly in the 2 week administration, but decreased to the control level in the 1 month administration. The increase of NGF may be caused by the proliferation of glial cells or the enhancement of neuronal production of NGF.

Enzyme-linked immunoassay for midkine, and its application to evaluation of midkine levels in developing mouse brain and sera from patients with hepatocellular carcinomas

Midkine (MK) is a growth factor that promotes neurite outgrowth and survival of neurons, and enhances the plasminogen activator in endothelial cells. A highly sensitive enzyme-linked immunoassay for MK was developed, involving affinity-purified anti-MK antibodies, their biotinylated form, and avidin-beta-galactosidase. The amount of bound avidin-beta-galactosidase was determined using a fluorogenic substrate, 4-methylumbelliferyl-beta-D-galactoside. This method allowed the detection of human and mouse MK in the range of 50 pg-10 ng. Pleiotrophin, which is related to MK in its amino acid sequence, did not show any cross reactivity. Employing this method, the MK levels in the developing mouse brain were determined. The MK level was 2 micrograms/g of wet tissue on the 12th day of gestation, and then steadily decreased during embryogenesis and postnatal development to 30 ng/g two months after birth. The assay method can also be applied to serum samples. Although the MK levels in the sera of normal human subjects were low or undetectable, 0.6-8 ng/ml of MK was detected in samples in the majority of cases of hepatocellular carcinomas.

Purification and characterization of a 39kDa apurinic/apyrimidinic endonuclease from mouse ascites sarcoma cells

We purified an apurinic/apyrimidinic (AP) endonuclease from mouse ascites sarcoma (SR-C3H/He) cells. The enzyme showed nicking activity on acid-depurinated DNA but not on untreated, intact DNA. It also showed priming activity for DNA polymerase on both acid-depurinated and bleomycin-damaged DNA. The priming activity on bleomycin-damaged DNA was two times higher than that on an acid-depurinated DNA. The enzymatic properties indicate that the enzyme is a class II AP endonuclease having DNA 3' repair diesterase activity. The purified enzyme has a molecular weight of 39,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimal pH for AP endonuclease activity was 8.0 in 50 mM Tris-HCl buffer. The AP endonuclease activity depended on divalent cation such as Mg2+ and Co2+ ions, and was inhibited by 2 mM EDTA with no addition of the divalent cation. An appropriate concentration of sodium or potassium salt stimulated the activity. Partial digestion of the AP endonuclease with Staphylococcus aureus V8 protease produced 4 major peptide fragments which may be used for protein sequencing.

Comparison of various methods of assaying the cytotoxic effects of ethanol on human hepatoblastoma cells (HUH-6 line)

The sensitivity of five kinds of cytotoxicity assays using ethanol on human hepatoblastoma cells (HUH-6 line), which were cultured as monolayers or spheroids, was compared. Ethanol was chosen as a test because it acts on cell membranes directly without being metabolized and exerts its cytotoxicity. The assay methods used were as follows: 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), colony formation, cell growth and DNA assays. The sensitivity of the assays was: LDH < DNA < cell growth < MTT < colony formation. LDH assay had the advantage that the same culture could be used for multiple assays, but when a small number of cells were assayed, no significant increase in the release of LDH was detected in the assay cultures compared with the control cultures. Although the DNA and cell growth assays were more sensitive than the LDH assay, the extent of cell damage may be underestimated because the damaged cells and DNA present in the cultures are included in the assay samples. On the other hand, both MTT and colony formation assays showed a high sensitivity. The MTT assay was done within 24 h after ethanol was added to the cultures and was applicable to both monolayer and spheroid cultures, while the colony formation assay required 1-2 weeks and it was applicable only to monolayer cultures. Taken together, the MTT assay was the most suitable method to evaluate the cytotoxic effects of ethanol on HUH-6 cells cultured as either monolayers or spheroids.

Meningeal sinus histiocytosis mimicking lymphoplasmacyte-rich meningioma. Case report

Extranodal sinus histiocytosis with massive lymphadenopathy involving the meninges is a rare clinical entity. The authors describe the unusual case of an occipital meningeal lesion in a 25-year-old man in whom they found inflammation of the occipital lobe mimicking lymphoplasmacyte-rich meningioma. The clinical similarities and differences are discussed.

Mutation in p53 and de-regulation of p53-related gene expression in three human cell lines immortalized with 4-nitroquinoline 1-oxide or 60Co gamma rays

In vitro models of malignant transformation of human cells may provide considerable insight into the mechanisms of multi-step carcinogenesis. It is well established that normal human cells must be immortalized before they can be malignantly transformed; however, they are stringently destined for aging and are rarely immortalized. The mechanism of cellular aging and immortalization is still unknown. We detected expression of only mutated p53 mRNA by direct sequencing of the reverse-transcribed mRNA in 3 human cell lines immortalized either with 4-nitroquinoline 1-oxide or with 60Co gamma rays. Consequently, only the mutated pS3 protein was expressed in each immortalized cell line. The expression of sdiI/p21 and mdm2, both of which are positively regulated by wild-type p53, was significantly down-regulated in the immortalized cell lines, resulting in over-expression of cdk2 and cdk4. Introduction of the sdiI/p21 gene into these cells was followed by a remarkable decrease in their ability to synthesize DNA. These results indicate that the p53 cascade may play an important role in the immortalization of human cells.

Distribution of activated complement, C3b, and its degraded fragments, iC3b/C3dg, in the colonic mucosa of ulcerative colitis (UC)

The third component of complement (C3) is central to both the classical and alternative pathways in complement activation. In this study, involvement of C3 activation in the mucosal injury of UC was investigated. We examined the distribution of activated (C3b) and degraded fragments (iC3b/C3dg) of C3, terminal complement complex (TCC), and complement regulatory proteins in normal and diseased colonic mucosa including UC and other types of colitis using immunohistochemical techniques at the level of light and electron microscopy. While C3b and iC3b/C3dg staining was negligible in the normal mucosa, iC3b/C3dg and, to a lesser extent, C3b were deposited in UC mucosa along the epithelial basement membrane. The deposition was enhanced in relation to the severity of mucosal inflammation (C3b, P less than 0.05; iC3b/C3dg, P less than 0.01). Epithelial deposition of TCC was not observed in most UC mucosa. Immunoelectron microscopy showed that C3b and iC3b/C3dg were distributed mainly along the epithelial basement membrane and the underlying connective tissue in a granular, studded manner, and weakly present along the basolateral surface of epithelial cells. These C3 fragments were also deposited in inflammatory control mucosa such as ischaemic and infectious colitis. Our findings suggest that deposition of the C3 fragments occurs in inflamed colonic mucosa of diverse etiologies, including UC, but to define a role of the deposition in the development of mucosal injury in UC awaits direct study.

Immunogenicity of Leucocytozoon caulleryi sporozoites and their reactivity with specific immune sera

The immunogenicity of Leucocytozoon caulleryi sporozoites for chickens and their reactivity in vitro with specific immune sera were studied. Almost all of the chickens that had been immunized with the sporozoite antigens survived the sporozoite challenge. The degree of parasitemia observed in the immunized chickens was significantly lower than that found in the nonimmunized chickens. Specific antibodies against sporozoites were tested by the circumsporozoite precipitation (CSP) reaction. Antibodies were demonstrated in the sera of chickens that had been immunized with the sporozoite antigens or chickens that had recovered from a primary infection with L. caulleryi sporozoites. When viable mature sporozoites were incubated in vitro with serum from immune chickens, agglutination and a long, thread-like precipitate at one end of the sporozoite could be seen within a few minutes under a phase-contrast microscope. The effects of specific immune serum on the infectivity of sporozoites were examined by the sporozoite neutralization activity (SNA) test. Sporozoites that had been incubated in vitro with serum from immune chickens lost their infectivity to chickens. The CSP reaction and the SNA test in L. caulleryi infection were stage- and species-specific.

Detection of hepatitis C virus RNA in circulating immune complexes by RT-PCR

BACKGROUND/AIMS

We investigate whether hepatitis C virus (HCV) forms a circulating immune complex (CIC) in patients with chronic HCV infection.

MATERIALS AND METHODS

We examined HCV-RNA immunoprecipitated with anti-human IgG, A and M antibodies by reverse transcription-polymerase chain reaction.

RESULTS

In thirty-nine (91%) of 43 patients, composed of 35 chronic hepatitis (CH) and 8 liver cirrhosis (LC), HCV-RNA was detected in the CIC. All 43 patients analyzed were classified into the following three categories; HCV-RNA was detected only in the supernatant (S pattern, 4 patients), both in the supernatant and the precipitate (SP pattern, 27 patients), and only in the precipitate (P pattern, 12 patients). SP pattern was most common in chronic HCV infection, and the frequency of SP pattern decreased with the progression of liver disease. P pattern was significantly more frequent in patients with higher gamma-globulin levels, histologically indicated LC, and antibody to HCV envelope protein.

CONCLUSION

We found that HCV formed a CIC in most patients with chronic HCV infection, and that the formation of CIC might be related to the stage of chronic HCV infection.

Increased expression of a brain/embryo-type myosin heavy chain isoform (MIIB2) in mesangial proliferative glomerulonephritis

Proliferation of mesangial cells is frequently found in glomerulonephritis, such as IgA glomerulonephritis. Recent reports suggest that a brain/embryo-type myosin isoform (MIIB2) is involved in cell proliferation. We have studied the expression of MIIB2 in renal biopsy samples from patients with various renal diseases and in the renal tissues from the rat model of mesangial proliferative glomerulonephritis induced with anti-Thy 1.1 antibody. Immunohistochemical analysis of the biopsy samples using an anti-brain-type myosin heavy chain-specific monoclonal antibody (HBM1) indicated that 92% of the samples from patients with IgA glomerulonephritis contained a significant population of mesangial cells that reacted with the antibody. Most of the samples from patients with other types of proliferative glomerular diseases also contained HBM1-reactive mesangial cells, while none of the samples from patients with non-proliferative glomerular diseases contained a significant population of HBM1-reactive mesangial cells. The expression of a brain/embryo-type myosin heavy chain isoform (MIIB2) in the mesangial cells began at five days after injection of anti-Thy 1.1 antibody and peaked at the tenth day. On the other hand, the expression of the proliferating cell nuclear antigen in the mesangial cells was induced at two days after injection of anti-Thy 1.1 antibody and was maximal at the fourth day. These results indicate that the expression of the MIIB2 isoform by mesangial cells is accelerated in proliferative glomerulonephritis and suggest that the myosin isoform is involved in the phenotypic transformations of the glomerular tissues rather than in the cell proliferation.

Characterization of murine stromal cell clones established from bone marrow and spleen

Stromal cell lines were established by irradiating adherent layers of bone marrow and spleen cells in Dexter-type long-term culture with X-rays. Some of these cell lines support myelopoiesis and/or B lymphopoiesis in vitro. Furthermore, the characteristics of these stromal cell lines were studied. Cytokine activity was detected in the conditioned media from all hematopoietic-supportive and non-supportive stromal cells. Quantitative reverse transcriptase-polymerase chain reaction analysis revealed that the mRNAs of macrophage colony-stimulating factor and stem cell factor, but not that of Interleukin-3, were detectable in all the hematopoietic-supportive and non-supportive stromal cell lines. The transcripts of granulocyte colony-stimulating factor, interleukin-6, interleukin-7, and leukemia inhibitory factor were expressed in a wide variety of cell lines. Most stromal cell lines synthesized mRNA of c-mpl, the ligand of which stimulates megakaryopoiesis and thrombopoiesis. These observations indicate that the pattern of mRNA expression of cytokines is not correlated with the hematopoietic-supportive ability of stromal cell lines. There was a significant difference in the efficiency of adhesion of lineage marker-negative bone marrow cells to fibroblasts and stromal cell lines. This appears to be correlated with the hematopoietic-supportive ability of the stromal cell lines.

A mutation in endothelin-B receptor gene causes myenteric aganglionosis and coat color spotting in rats

Congenital aganglionosis rat (AR) is a mutant with an autosomal recessive gene (sl), which shows megacolon caused by the absence of myenteric ganglion cells and white coat-color with a small pigmented spot on the head. Recently, targeted disruption of the endothelin-B (ETB) receptor gene (EDNRB) in the mouse has been reported to cause aganglionic megacolon and coat color spotting resembling the phenotypes of the sl/sl rats. To identify the mutation responsible for the phenotypes of the sl/sl rats, we determined the nucleotide sequences of the EDNRB genes of the sl/sl rats and found that a 301-bp region intervening between direct repeat sequences was deleted in the EDNRB gene, and the deletion produces various transcripts due to aberrant splicing.