Antitumor effects of a refined polysaccharide peptide fraction isolated from Coriolus versicolor: in vitro and in vivo studies

RPSP, a refined polysaccharide peptide fraction isolated by fast performance liquid chromatography (FPLC) from the crude powder of total peptide-bound polysaccharides of cultivated Coriolus versicolor Cov-1 dose-dependently inhibited the proliferation of a human hepatoma cell line (HEPG2). The effective dose causing 50% inhibition following 3-day exposure to RPSP was 243 +/- 36 micrograms/ml for HEPG2. However, little or no inhibitory effects were detected in normal human foetal hepatocytes. On the other hand, in the pretreatment group, in which RPSP was administered i.p. for two weeks before sarcoma 180 inoculation in nude mice, the incidence of tumor growth was less (2 out of 5 mice) than that of the control group (all 5 mice). The tumor size of the control group was about 3-5 times bigger than that of the pretreatment group. In tumor-bearing nude mice, 5 days after sarcoma 180 inoculation, i.v. administration of RPSP significantly suppressed the growth of tumor mass. The inhibition rate was 93.6% on day 13. Furthermore, administration of RPSP did not cause any pathological lesions in vital organs of rabbits such as heart, liver, spleen, lung and kidney. In conclusion, these results indicate that RPSP acts by directly suppressing tumor cell growth in vitro and the prevention of in vivo growth of tumor mass is probably mediated also via its immunomodulating effects.

Viral vector transduction of the human deoxycytidine kinase cDNA sensitizes glioma cells to the cytotoxic effects of cytosine arabinoside in vitro and in vivo

Cytosine arabinoside (ara-C) is a cytidine analog that incorporates into replicating DNA and induces lethal DNA strand breaks. Although ara-C is a potent antitumor agent for hematologic malignancies, it has only minimal activity against most solid tumors. The rate-limiting step in intracellular ara-C activation is phosphorylation of the prodrug by deoxycytidine kinase (dCK). The present results demonstrate that both retroviral and adenoviral vector-mediated transduction of the dCK cDNA results in marked sensitization of glioma cells lines to the cytotoxic effects of ara-C in vitro. We also demonstrate that ara-C treatment of established intradermal and intracerebral gliomas transduced with dCK results in significant antitumor effects in vivo. These data suggest that viral vector transduction of the dCK gene followed by treatment with ara-C represents a new chemosensitization strategy for cancer gene therapy.

In vivo replication-deficient adenovirus vector-mediated transduction of the cytosine deaminase gene sensitizes glioma cells to 5-fluorocytosine

Viral vector-mediated transfer of chemosensitization genes represents a promising new approach to the treatment of cancer. Previous reports have demonstrated that transfection of the bacterial cytosine deaminase (cd) gene into mammalian cells can sensitize them to the otherwise nontoxic nucleoside, 5-fluorocytosine (5-FC). We now report that a replication-deficient adenovirus vector that transduces the cd gene (Ad.CMV-cd) highly sensitizes 9L gliosarcoma cells to 5-FC, and that gene transduction is associated with a potent bystander effect that is not dependent on direct cell-to-cell contact. Stereotactic injection of Ad.CMV-cd into established rat gliomas, followed by systemic administration of 5-FC in vivo, results in prolongation of survival.

[Preliminary diagnostic criteria for primary Sjogren's syndrome in China]

Primary Sjogren's syndrome (pSS) is a common autoimmune connective tissue disease in China yet without a universally accepted diagnostic criteria. In this study a new criteria was proposed and compared with other six sets of criteria. Fifty-five items in 112 pSS and 185 controls were evaluated. Results show the criteria we proposed contained one major and nine minor items. For the purpose of identifying patients in clinical studies, a major with at least three of the nine minor items or at least five of the minor items should be presented. The major item is anti-SSA/SSB(+) and the minors are, (1) dry eyes or dry mouth (> 3 months, persistently), (2) swollen salivary glands (recurrently or persistently), (3) rampant dental caries, (4) Schirmer test (< 5 mm in 5 min.) or corneal staining(+), (5) unstimulated salivary flow (< 0.03 ml/min) or abornal parotid sialography, (6) minor salivary gland biopsy (> or = 1 focus), (7) renal tubular acidosis, (8) hypergammaglobuminemia (gamma globulin > or = 30%) or hypergammaglobuminemic purpura, (9) RF > 1 : 20 or ANA > 1 : 20. Other connective tissure diseases, pre-existing lymphoma, AIDS, sarcoidosis, graft vs host disease must be excluded. The criteria we proposed had a high specificity of 98.2% and sensitivity of 94.1%.

[CuZn-SOD determination of sera in patients with rheumatic diseases]

Superoxide anion (O2.-) plays an important part in reactive oxygen species (ROS). In order to explore its effect on the pathogenesis of rheumatic diseases, authors had determined CuZn-SOD contents of sera in 132 subjects involving the patients of rheumatic diseases (SLE, RA, etc), non-rheumatic diseases and normal controls by using enzyme linked immunosorbent assay (ELISA). The results showed the followings: CuZn-SOD contents of 27 normal subjects: 98.80 +/- 20.74 ng/ml (x +/- s); that of 27 non-rheumatic diseases cases: 72.24 +/- 16.60 ng/ml (x +/- s); of 22 SLE cases: 56.56 +/- 19.27 ng/ml (x +/- s); of 27 RA cases: 61.56 +/- 20.53 ng/ml (x +/- s); of 29 other rheumatic diseases cases: 68.97 +/- 17.79 ng/ml (x +/- s). Statistical test was made: both CuZn-SOD contents of rheumatic disease and non-rheumatic disease were lower than that of normal subjects with more significant difference (P < 0.001); compared with that of non-rheumatic diseases patients, SLE cases had significant difference (P < 0.01); RA cases had significant difference (P < 0.05); other cases of rheumatic diseases had no statistical differrence (P > 0.05). Above results suggest that superoxide anion is a non-specific inflammatory mediator which contributes to disorders with inflammatory damages (rheumatic or non-rheumatic diseases), where CuZn-SOD content tested was obviously lower than normal subjects; among the rheumatic disease patients, CuZn-SOD contents of the sera of SLE patients were the lowest because of its more autoimmune antibody, more severe inflammatory and immunological reaction. This work laid the theoretical and experimental foundation for the clinical application of exogenous CuZn-SOD in the treatment of rheumatic diseases. Combined use of CuZn-SOD scavengers may get better result because of the complexibility of ROS inflammatory mechanism.

[Ribozyme targeted the point-mutation of activated oncogene inhibits its expression in vivo]

We demonstrated previously that the hammerhead ribozyme designed by us against the activated oncogene T24-ras cleaved the target mRNA specifically and efficiently in vitro. To study its properties in vivo, we cloned the DNA fragment encoding the ribozyme into the eukaryotic expression vector pSMG and transfected it into the T24-ras gene transformed NIH3T3 cell lines. The intracellular cleavage of T24-ras mRNA was evaluated on either the cytological level or the molecular level. The malignant cells expressing ribozyme were partially reversed in morphology as evidenced by slower growth speed, partial recovery of contact-inhibition, reduced frequency of colony forming in soft agar and close-to-normal behaviour in agglutination teat. The primer extension experiment verified that the ribozyme had efficiently cleaved the transcripts of T24-ras gene at the target site in vivo.

[Expression of p53 in human esophageal carcinoma and pre-malignant lesions in the esophagus]

The levels of p53 protein were detected by immunocytochemistry in 197 endoscopic biopsy specimens of esophagus. Nuclear p53 protein was present in 2.9% of normal mucosa, 6.7% of inflammatory mucosa, 38.8% of mild dysplasia, 52.0% of moderate or severe dysplasia, 61.1% of carcinomas in situ, 62.5% of invasive carcinomas. Moreover, we examined 14 cases of esophageal carcinoma with extensive dysplasia near the carcinoma and found high levels of p53 protein in both dysplasias and carcinomas in 8 cases. In one case, carcinoma presented high level of p53 protein while the adjacent dysplasia did not. In another case, the result was just the opposite. Negativity for p53 immunostaining was found in 4 cases. These data indicated that p53 protein accumulation occurred before tumor invasion in the multistage esophageal carcinogenesis. The timing and the frequency of p53 protein accumulation made p53 gene an attractive marker for the early diagnosis an the evaluation of chemopreventive agents.

Breast cancer selective gene expression and therapy mediated by recombinant adenoviruses containing the DF3/MUC1 promoter

The high molecular weight mucin-like glycoprotein, DF3 (MUC1), is overexpressed in the majority of human breast cancers. Here we demonstrate that replication defective recombinant adenoviral vectors, containing the DF3 promoter (bp -725 to +31), can be used to express beta-galactosidase (Ad.DF3-betagal) and the herpes simplex virus thymidine kinase (HSV-tk) gene (Ad.Df3-tk) in DF3 positive breast carcinoma cell lines. In vivo experiments using breast tumor implants in nude mice injected with Ad.DF3-betagal demonstrated that expression of the beta-galactosidase gene is limited to DF3-positive breast cancer xenografts. Moreover, in an intraperitoneal breast cancer metastases model, we show that i.p. injection of Ad.DF3-tk followed by GCV treatment results in inhibition of tumor growth. These results demonstrate that utilization of the DF3 promoter in an adenoviral vector can confer selective expression of heterologous genes in breast cancer cells in vitro and in vivo.

Ins(1,4,5)P3 activates Drosophila cation channel Trpl in recombinant baculovirus-infected Sf9 insect cells

The trp-like (trpl) gene product (Trpl) is thought to form a nonselective cation channel important for signal transduction in Drosophila photoreceptor cells. This channel may be the insect homologue of mammalian channels involved in Ca2+ signal transduction. To determine the mechanism of receptor-mediated activation of Trpl, whole cell membrane currents were examined in Sf9 insect cells after infection with recombinant baculovirus. Stimulation by bradykinin increased whole cell Trpl currents three- to fivefold. Similar activation of Trpl was observed by inclusion of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] in the pipette solution during whole cell recordings. These currents were 1) not seen in noninfected cells or in cells expressing only the B2 receptor, 2) mimicked by D-myo-inositol 2,4,5-trisphosphate, and 3-deoxy-3-fluoro-D-myo-inositol 1,4,5-trisphosphate, 3) not seen with D-myo-inositol 1,4-bisphosphate or D-myo-inositol 1,3,4,5-tetrakisphosphate, and 4) blocked by heparin, but not by de-N-sulfated heparin. In contrast, Trpl currents were unaffected by thapsigargin. These results demonstrate that the Trpl cation channel is activated by Ins(1,4,5)P3 in a heparin-sensitive fashion. Regulation of channel activity by Ins(1,4,5)P3 may occur by a number of mechanisms, including direct binding of Ins(1,4,5)P3 to the Trpl channel or direct physical interaction between the Ins(1,4,5)P3 receptor/Ca(2+)-release channel of the endoplasmic reticulum and the Trpl protein.

Ultrastructural cytochemistry of human gastric cancer: electron microscopic observations of five organellae marker enzymes

The distribution of ALPase, ACPase, G6Pase TPPase and CCOase of gastric cancer and normal gastric epithelium were studied ultrastructurally. The results showed that normal gastric epithelium had no ALPase reaction. The reactions of ACPase, G6Pase, TPPase and CCOase were found in the corresponding organellae which were consistent with their functions. In tubular adenocarcinoma cells, their reactions were more apparent in the corresponding organellae. Some cells of tubular adenocarcinomas showed ALPase reaction. The mucinous adenocarcinoma cells had higher ACPase and TPPase reactions. In poorly differentiated adenocarcinoma cells, the five marker enzymes showed negative or faint reactions. The biological significance and mechanisms of distribution of the five marker enzymes were discussed.

[Effect of sex steroids on serum amyloid P-component (female protein) in rats]

Serum amyloid P-component (SAP) has been designated as a female protein in hamsters. But such a distinction is not made for rats. In order to investigate the effects of sex-steroids on the SAP level in rats, SAP was purified from Wistar rats by affinity chromatography of phosphorylcholine, followed by gel filtration. Anti-SAP was raised through the immunization of rabbits with the rat SAP and Freund's adjuvant. Sample sera were obtained from 180 young and old rats, after which rats were injected with estradiol (E2), testosterone (T) or dehydroepiandrosterone (DHEA). Sera were serially obtained from the tail vessels until the 8th day after injection. The SAP level was assayed by micro single radial immunodiffusion. As the rats aged, the SAP levels increased from 2.9 mg/dl at 11 weeks to 10.7mg/dl at 58 weeks. In 37-week-old rats, the SAP levels in females (6.3 +/- 1.8 mg/dl) were significantly (p < 0.001) higher than those in males (3.9 +/- 1.0 mg/dl). The SAP levels did not change after T administration, but were increased rapidly by E2 administration, especially in young male rats (increased from 2.6 +/- 0.2 mg/dl to 4.9 +/- 0.7 mg/dl). The SAP levels were decreased significantly (p < 0.05) by DHEA injection. Serum E2 levels in young (11 wk) male rats were very low before E2 injection, and rose steeply on the 2nd day. From these findings, the different SAP levels in mature female and male rats are attributed to E2.

[Interspecific protoplast fusion between Bacillus thuringensis Bt-3701 and Bacillus megaterium Bm-107]

The results of the interspecific protoplast fusion between B. thuringensis sub. kurstaki Bt-3701 which has pesticide ability, and B. megaterium var. phosphaticum Bm-107 which has decomposing phosphate activity, were reported. High frequency of protoplast formation and regeneration was obtained with 4h activated Bm-107 treated by 100 micrograms/ml lysozyme, and with 2h activated Bt-3701 treated by 3% glycin and mild temperature. Using 40% PEG and 5% nascent Ca2+ to treat the parential protoplast mixture for 3 min at 37 degrees C, 4 stable fusants were obtained. Biological tests show that they have both pesticide ability and decomposing phosphate activity, but which are weaker than that of parential strains.

Changes in lens connexin expression lead to increased gap junctional voltage dependence and conductance

The differentiation of mouse lens epithelial cells into fiber cells is a useful model for studying the changes of the electrical properties of gap junction (cell-to-cell) channels that are induced by an alteration in connexin expression patterns. In this model, cuboidal lens epithelial cells differentiate into elongated fiber cells, and the expression of connexin43 (Cx43) in the epithelial cells is replaced with the production of high levels of Cx50 and Cx46 in the fiber cells. We now report a new procedure to isolate mouse lens fiber cell pairs suitable for double whole cell patch-clamp analysis. Analysis was also performed for fiberlike cell pairs differentiated from epithelial cells in culture. Voltage dependence and unitary conductance of fiber cell gap junction channels were determined and compared with the corresponding values previously measured for the channels joining lens epithelial cells and for lens connexin channels formed in Xenopus oocyte pairs. Our results support a differentiation-induced shift toward stronger gap junctional voltage dependence and larger unitary conductances in the fiber cells. Our data further reflect a balanced functional contribution of Cx50 and Cx46 in the fiber cell-to-cell channels rather than a predominance of a single connexin.

Ocular lens gap junctions: protein expression, assembly, and structure-function analysis

Recent advances in understanding lens fiber gap junction formation are reviewed. These include studies of junctional protein expression in the embryonic lens, and of age related changes affecting gap junction structure and composition in the adult lens. An in vitro assembly system based on detergent solubilized pore complexes and endogenous lipids has been developed to provide information on the molecular interactions involved in gap junction formation and to provide material for structure analysis. Important information on the electrical properties of lens gap junction channels is obtained using electrophysiological techniques including planar lipid bilayer analysis and patch clamping.

An association study between essential hypertension and HLA-DRB1 alleles

It is well established that genetic and environmental factors are involved in the etiology of essential hypertension (EH). Previous studies have suggested that at least one of the HLA genes is responsible for the genetic susceptibility to EH. Our aim in the present study was to investigate this issue in China by the PCR-SSP HLA-DRB1 typing method. The results showed an increased frequency of HLA-DR2 and a decreased frequency of HLA-DR7 with EH patients compared with controls. We consider that HLA-DR2 may represent a marker for susceptibility to EH in the North Chinese population.

Insulin-like growth factor (IGF) I and retinoic acid induce the synthesis of IGF-binding protein 5 in rat osteoblastic cells

The insulin-like growth factor (IGF) regulatory system has a major impact on bone physiology. Among the modulators of IGFs, a family of structurally related proteins, the IGF-binding proteins (IGFBPs), have been shown to either potentiate or inhibit IGF actions on bone growth. However, the regulation of IGFBP expression in bone cells is not completely understood. In the present study, the expression of IGFBP-5 was analyzed in primary osteoblastic cells (Ob cells) isolated from 22-day-old fetal rat calvariae. Treatment of Ob cells with either IGF-I or all-trans-retinoic acid (RA) caused a time- and dose-dependent increase in IGFBP-5 messenger RNA (mRNA) levels, as determined by Northern blot analysis. Stimulation of IGFBP-5 mRNA was obtained at 100 nM IGF-I between 6 and 16 h (2- to 2.5-fold) and 100 nM RA between 16 and 24 h (3- to 4-fold). Concomitant treatment of Ob cells with IGF-I and RA revealed an additive effect and a 5- to 7-fold increase in IGFBP-5 mRNA levels after 16-24 h. The effect of IGF-I and RA and their combination on IGFBP-5 transcripts was similar in confluent and subconfluent cultures of Ob cells. IGF-I and RA did not change IGFBP-5 mRNA stability in Ob cells after transcription arrest with the RNA polymerase II inhibitor 5,6-dichloro-1-beta-D-ribofuranosyl benzimidazole. IGF-I and RA at 100 nM elevated the levels of IGFBP-5 heterogenous nuclear RNA, measured by reverse transcription-polymerase chain reaction. The effect was similar to that observed on mRNA levels. IGFBP-5 from rat Ob cells appeared as a single band of 31 kilodaltons in both the conditioned medium and the extracellular matrix as determined by Western immunoblots. IGF-I and RA, both at 100 nM, increased IGFBP-5 by 2- to 3-fold after 24 h. In conclusion, IGF-I and RA modify the synthesis and secretion of IGFBP-5 in rat Ob cells through pathways that may involve increased transcription and elongation and/or altered processing of heterogenous nuclear RNA. Our data suggest that IGFBP-5 may play a role in the osteoblastic-differentiated function regulated by IGF-I and RA.

Prevalence of primary Sjögren's syndrome in China

OBJECTIVE

To determine the prevalence rate of primary Sjögren's syndrome (SS) in a community population of 2066 adults in a Beijing suburban village, and 100 inpatients, who were not necessarily admitted for rheumatic diseases.

METHODS

Questionnaire and serological studies of antinuclear antibodies, rheumatoid factor, and anti-SSA, anti-SSB antibodies were done. Possible positive subjects were given eye and oral examinations for objective evidence of xerostomia and keratoconjunctivitis sicca.

RESULTS

According to the Copenhagen criteria, the prevalence rate of primary Sjögren's syndrome in China was 0.77%, and it was 0.33% by modified San Diego criteria. In 100 inpatients, we found 4 cases of primary Sjögren's syndrome by Copenhagen criteria, and one case by modified San Diego criteria.

CONCLUSION

Primary Sjögren's syndrome is not a rare disease in China, but most cases are overlooked or misdiagnosed.

An upstream control region required for inducible transcription of the mouse H1(zero) histone gene during terminal differentiation

The replacement linker histone H1 (zero) is associated with terminal differentiation in many mammalian cell types, and its accumulation in chromatin may contribute to transcriptional repression occurring during terminal differentiation. H1 (zero) also accumulates in a variety of cell culture lines undergoing terminal differentiation. During in vitro mouse erythroleukemia cell differentiation, H1 (zero) gene expression is induced very rapidly, prior to the time when the cells actually commit to terminal differentiation. We have used a combination of transfection assays and in vitro DNA-protein interaction studies to identify nuclear protein binding sites in the H1 (zero) promoter that control expression and induction of the H1(zero) gene in mouse erythroleukemia cells. The results indicate that transcription of the H1 (zero) gene is controlled by three elements present in the upstream region of the promoter between positions -305 and -470. Site-directed mutagenesis of each of these elements showed that one of them controls inducibility of the gene in differentiating cells. The other two elements in the upstream control region affect primarily the level of transcription of the gene in undifferentiated and differentiating cells. These two elements share a DNA sequence motif consisting of a (dG)6 tract contained in an eight-base consensus, (A/C)GGGGGG(A/C). Additional copies of this motif are present elsewhere in the H1 (zero) promoter.

Rapid HLA-DRB1 generic typing by PCR-SSP method

We report a simple and rapid HLA-DRB1 generic typing method, PCR-SSP, which is practical and inexpensive. We use 9 sequence-specific primers and 2 group specific primers to define the HLA-DRB1 specificities DR1, DR2, DR3, DR4, DR5, DR6, DR7, DR8, DR9 and DR10. The HLA DR3, DR5, DR6 and DR8 can be amplified by the two primers of DR3568 and DRB1. The DR6 specificity can be identified by excluding the DR3, DR5 and DR8 when the DR3568 are positive. Any individuals can be typed with some exception: the three pairs of phenotype DR3/DR3 and DR3/DR6, DR5/DR5 and DR5/DR6, DR8/DR8 and DR8/DR6 cannot be discriminated from each other. We typed 106 unrelated healthy people from Beijing locations in two weeks. We think this typing method is suitable to replace the error-prone serologic HLA-DR tests in routine clinical practice, including the prospective typing of cadaveric organ donors.

[Investigation of blood supply of bronchogenic carcinoma deriving from pulmonary artery]

Microfil perfusion technique was used to investigate the blood supply of bronchogenic carcinoma deriving from pulmonary artery on 20 fresh specimens of lung cancer, including 11 squamous carcinoma, 6 adenocarcinoma, 1 alveolar cell carcinoma and 2 undifferentiated carcinoma cases. The results showed that the appearance and quantity of pulmonary blood supply of bronchogenic carcinoma depended on and changed with the site, activity, growth mode as well as the local condition of tumor nodules; pulmonary artery supplied blood to the periphery of the tumor and its innermost part as well; vessels from pulmonary artery in tumor nodules were generally less in number than those in the surrouding normal lung tissues around. The results suggested that the tumor blood supply from pulmonary artery should be evaluated comprehensively and dynamically; during interventional chemotherapy via pulmonary artery, patients should be selected carefully and the catheter for infusion placed in suitable position so as to gain the best therapeutic effect.

[The effect of sagittal split ramus osteotomy advancement and setback mandible on occlusal force and masticatory efficiency]

21 patients (mandibular prognathism = 11, mandibular retrognathism = 10) whose occlusal force and masticatory efficiency were measured and analysed preoperatively, three and six months following sagittal split ramus osteotomy. The result shows that, in individuals with mandibular retrognathism treated by lengthening of the mandible, the occlusal force and masticatory efficiency would decrease, in individuals with mandibular prognathism treated by reduction in mandibular length, the occlusal force and masticatory efficiency would increase. There is no linear correlation relationship between the change of the occlusal force and the movement of the angle and the distance of the mandible.

Mechanisms of glucocorticoid action in bone cells

Glucocorticoids play an important role in the normal regulation of bone remodeling; however continued exposure of bone to glucocorticoid excess results in osteoporosis. In vivo, glucocorticoids stimulate bone resorption and decrease bone formation, and in vitro studies have shown that while glucocorticoids stimulate osteoblastic differentiation, they have important inhibitory actions on bone formation. Glucocorticoids have many effects on osteoblast gene expression, including down-regulation of type I collagen and osteocalcin, and up-regulation of interstitial collagenase. The synthesis and activity of osteoblast growth factors can be modulated by glucocorticoids as well. For example, insulin-like growth factor I (IGF-I) is an important stimulator of osteoblast function, and expression of IGF-I is decreased by glucocorticoids. The activity of IGF I can be modified by IGF binding proteins (IGFBPs), and their synthesis is also regulated by glucocorticoids. Thus, glucocorticoid action on osteoblasts can be direct, by activating or repressing osteoblast gene expression, or indirect by altering the expression or activity of osteoblast growth factors. Further investigation of the mechanisms by which glucocorticoids modulate gene expression in bone cells will contribute to our understanding of steroid hormone biology and will provide a basis for the design of effective treatments for glucocorticoid-induced osteoporosis.

Volume-activated chloride current is not related to P-glycoprotein overexpression

It has been suggested that P-glycoprotein (P-gp), an ATP-dependent transporter responsible for classical multidrug resistance, is also a volume-regulated chloride channel. We reexamined this hypothesis by use of whole-cell patch clamp recordings of three matched pairs of cell lines, which were either drug-sensitive or drug-resistant due to P-gp overexpression. We demonstrate here that volume-regulated chloride-selective currents can be induced in cells with or without P-gp expression. Overexpression of either P-gp or cystic fibrosis transmembrane conductance regulator, the protein product of the CF gene and another member of the ATP-dependent transporters, is associated with a hypotonicity-induced, rapid onset, transient current prior to onset of the volume-sensitive chloride-selective current, an apparent nonspecific effect related to the overexpression of an integral membrane protein. These results suggest that there is no relationship between P-gp and the chloride channel activated by cell swelling.

[The abnormalities of the cellular immunity in rheumatoid synovium]

With the technique of immunohistochemical (ABC) method monoclonal antibodies were used to identify the lymphocyte subsets, macrophage and the expression of class II MHC (HLA-DR, HLA-DQ) antigens in the synovium cells from 18 RA patients and 8 patients with osteoarthritis as control. The results showed that the main cellular abnormality at the sublayer of the synovium was the appearance of lymphoid follicles which mainly consisted of the infiltration of T lymphocytes (77.8%).50.6% of them were CD4+, which mainly consisted by of CD45RO+ cells in the rheumatoid synovium on the consecutive sections. The increased ratio of CD4/CD8 in RA patients was significantly higher when compared with that in the controls (2.11 +/- 0.93 vs 0.63 +/- 0.13, P < 0.001). In advanced RA with fibrosis of joints, the ratio tended to decrease and was accompanied with reduction of infiltrated lymphocytes. Compared with T cells CD20+ B lymphocyte not only had a lower percentage (25.2%), but also showed a characteristic picture of locating in the centre of the follicles. The fact that most of the CD4+ T cells was helper memorized lymphocytes with CD4 phenotype of positive TAC(+) (interleukin-2 receptor) and that up to 54.2% was anti-HLA-DR and 54.1% anti-HLA-DQ monoclonal antibodies indicated that these T lymphocytes were activated in vivo. Cells with anti-CD68+ were seen all over the RA synovium. Class II HLA and CD68 molecule were also expressed on the endothelium cells of the small vessels. It is suggested that the activated lymphocytes, macrophages and endothelium cells and their abnormal distribution may indicate the abnormalities of the cellular immunity in rheumatoid synovium.

Differential expression of two gap junction proteins in corneal epithelium

Two distinct gap junction proteins (connexins) are expressed in rat corneal epithelium in a way which parallels cellular differentiation processes in this tissue. Connexin43 is restricted predominantly to the basal cells of the corneal epithelium and is present in significantly reduced amounts compared to the situation in the adjacent conjunctival epithelium. In contrast, a gap junction protein recognized by antibodies against MP70 which is the ovine homolog of mouse connexin50, is strongly expressed in the corneal epithelium and is present in the basal cells, wing cells and surface cells. While the functional significance of this differential expression of corneal epithelial connexins has yet to be established, the corneal epithelium is the third avascular tissue besides lens and heart valves which expresses a gap junction protein recognized by anti-MP70 antibodies.

Isolation and characterization of two replication-dependent mouse H1 histone genes

Mice contain at least seven nonallelic forms of the H1 histones, including the somatic variants H1a-e and less closely related variants H1 degrees and H1t. The mouse H1 degrees and H1c (H1var.1) genes were isolated and characterized previously. We have now isolated, sequenced and studied the expression properties of two additional mouse H1 genes, termed H1var.2 and H1var.3. Extensive amino acid and nucleotide sequence comparisons were made between the two genes and other mammalian H1 histone genes. A high degree of nucleotide sequence identity was seen between the H1var.2, rat H1d and human H1b genes, even well beyond the coding region, indicating that these genes are likely homologues. Unlike the previously characterized mouse H1var.1 gene which produces both nonpolyadenylated and polyadenylated mRNAs, the H1var.2 and H1var.3 genes produce only typical, replication dependent, nonpolyadenylated mRNAs.

Identification of the catalytic base in long chain acyl-CoA dehydrogenase

We have used molecular modeling and site-directed mutagenesis to identify the catalytic residues of human long chain acyl-CoA dehydrogenase. Among the acyl-CoA dehydrogenases, a family of flavoenzymes involved in beta-oxidation of fatty acids, only the three-dimensional structure of the medium chain fatty acid specific enzyme from pig liver has been determined (Kim, J.-J.P., Wang, M., & Paschke, R. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 7523-7527). Despite the overall sequence homology, the catalytic residue (E376) of medium chain acyl-CoA dehydrogenase is not conserved in isovaleryl- and long chain acyl-CoA dehydrogenases. A molecular model of human long chain acyl-CoA dehydrogenase was derived using atomic coordinates determined by X-ray diffraction studies of the pig medium chain specific enzyme, interactive graphics, and molecular mechanics calculations. The model suggests that E261 functions as the catalytic base in the long-chain dehydrogenase. An altered dehydrogenase in which E261 was replaced by a glutamine was constructed, expressed, purified, and characterized. The mutant enzyme exhibited less than 0.02% of the wild-type activity. These data strongly suggest that E261 is the base that abstracts the alpha-proton of the acyl-CoA substrate in the catalytic pathway of this dehydrogenase.

Transcriptional regulation of differentiation, selective toxicity and ATGCAAAT binding of bisbenzimidazole derivatives in human melanoma cells

To study the relationship between the structure of minor groove ligands and their affinity for specific DNA sequences that regulate gene transcription, three analogues of the A-T-specific DNA minor groove ligands Hoechst 33258 and Hoechst 33342 were synthesized with 5, 8 or 12 carbons in an aliphatic chain attached to the phenolic oxygen of the molecule. There was a striking bimodal relationship between toxicity to HeLa cells and the lipophilicity of the five analogues, toxicity being low for the compounds with a free hydroxyl (Hoechst 33258) or a 12-carbon substituent, yet high for the 5-carbon analogue. Selective killing of human melanoma cells compared with normal fibroblasts was observed for the Hoechst analogue with a 12-carbon chain attached. Hoechst 33258 itself was selectively toxic for the MM96E melanoma cell line compared with other cell lines, induced a highly dendritic morphology, increased tyrosinase activity and tyrosinase mRNA but decreased the level of gp75 (TRP-1) mRNA; message for a third pigment gene, Pmel-17, was unchanged. Tyrosinase activity was decreased in the resistant A2058 melanoma cell line and transcription was affected to a lesser extent than in MM96E. Expression of gp75 protein and two intermediate filament proteins was inhibited by Hoechst 33258 in MM96E cells. There was no major difference in the amount of 125I-Hoechst 33258 taken up by sensitive and resistant cells. Of the five derivatives studied, the parent drug Hoechst 33258 and the 2-carbon analogue (Hoechst 33342) were found to have the most inhibitory effect on affinity of octamer binding proteins for the ATGCAAAT consensus sequence found in the promoter region of certain genes associated with proliferation and differentiation. In contrast to Distamycin A (also an A-T-specific minor groove ligand), Hoechst 33258 displaced proteins already bound to the octamer motif. The G-C ligand chromomycin A3 exhibited a different spectrum of cell toxicity and tyrosinase stimulation compared with Hoechst 33258. Chromomycin A3 but not Hoechst 33258, strongly inhibited the zinc-dependent transcriptional activity of the sheep metallothionein-Ia promoter in reporter gene assays of transfected cells. Since the six metal-responsive elements of the promoter are GC-rich, this provides independent evidence for the sequence-specificity of transcriptional inactivation by one of these drugs in melanoma cells. Overall, the results suggest that Hoechst 33258 acts by inhibiting the transcription of specific genes, cell lines evidently differing in the accessibility to drugs of certain A-T-rich sequences.

The N-glycosidase mechanism of ribosome-inactivating proteins implied by crystal structures of alpha-momorcharin

BACKGROUND

alpha-Momorcharin (alpha MMC) is a type I ribosome-inactivating protein. It inhibits protein synthesis by hydrolytically removing a specific adenine residue from a highly conserved, single-stranded loop of rRNA.

RESULTS

Here we describe the determination and refinement of the crystal structures of alpha MMC in the native state and in complexes with the product, adenine, and a substrate analogue, formycin 5'-monophosphate (FMP) at high resolution. Both adenine and the base of FMP are tightly bound; the ribose of bound FMP adopts a strained, high-energy conformation, which may mimic the structure of the transition state.

CONCLUSIONS

These structures indicate that residues Tyr70, Glu160 and Arg163 of alpha MMC are the most critical for catalysis. We propose that the strained conformation of the ribose in the target adenosine weakens the glycoside bond. Partial protonation mediated by Arg163 then facilitates N-glycoside bond cleavage, leading to the formation of an oxycarbonium ion intermediate which is stabilized by the negatively-charged Glu160. Tyr70 adopts subtly different conformations in the three structures implying that it may be important in substrate recognition and perhaps catalysis.

Effects of mastication on digestion of whole cereal grains by cattle

A study was conducted to evaluate the effects of mastication on the physical breakdown and ruminal digestion of whole cereal grains by cattle. Three Hereford cows (initial BW 557 kg; SD, 17) surgically fitted with ruminal and esophageal fistulas were fed 5.5 kg/d (as-fed basis) of whole barley, corn, or wheat in an experiment designed as a 3 x 3 Latin square. Eating time and chews per kilogram of DM were greater (P < .10) for corn than for barley or wheat. Whole corn was substantially damaged after ingestive mastication, and the majority of kernels were broken into small pieces. Many barley and wheat kernels showed signs of dentition, but most kernels remained intact. Less saliva (P < .10) was added to whole wheat than to barley or corn during ingestive mastication. Cattle fed whole barley spent twice (P < .10) as long ruminating per kilogram of DM as those fed corn, with intermediate times for wheat. Less than 30% of the DM disappeared from unmasticated whole grains during 96 h of ruminal incubation. Ingestive mastication increased DM digestion to 53, 69, and 66% for barley, corn, and wheat, respectively. Mastication alters the kinetics of ruminal digestion of unprocessed cereal grains. Combined with the inherent protein and starch digestibilities of the grain, mastication affects the type and extent of processing required to optimize the utilization of cereal grains by cattle. Unlike barley and wheat, corn kernels are extensively damaged during ingestive mastication, reducing the need for physical processing.

[Effect of intracerebroventricular injection of norepinephrine and serotonin on somatosensory evoked potentials in rabbits]

The components of somatosensory evoked potentials (SEP), P7, N9, P12, and N15, were recorded from dura mater before and after intracerebroventricular injection (icv) of monoamines. The peak latencies of P12 and N15 were prolonged and the amplitudes of P12 and N15 were decreased following icv norepinephrine (NE) 1 microgram.microliter-1 and serotonin (5-HT) 1 microgram.microliter-1. Generally, P12 and N15 restored to normal 1-2 h after icv NE and 5-HT. Dopamine (DA) 1 microgram.microliter-1, however, did not show any significant effect on SEP. Tolazoline (Tol) 2.5 micrograms.microliters-1 markedly potentiated the inhibitory effect of NE, but propranolol (Pro) 1 microgram.microliter-1 weakened the effect of NE on SEP. These results indicated that icv NE and 5-HT exerted an inhibitory effect on the somatosensory afferent function from thalamus to cortex and/or intercortical areas and alpha-adrenoceptor had an influence on the inhibitory effect of NE.

A new macrophage differentiation antigen which is a member of the scavenger receptor superfamily

The antibodies Ki-M8, Ber-Mac3, GHI/61 and SM4 define a human macrophage-associated antigen with a relative molecular mass of 130,000 which we designate M130. The protein was purified by immunoaffinity chromatography and an N-terminal and three internal amino acid sequences were obtained. A cDNA fragment was initially obtained by polymerase chain reaction (PCR) using reverse-translated primers. Several variant cDNA clones, derived from alternative spliced messages, were obtained from a lipopolysaccharide-stimulated human monocyte library and were sequenced. The relative abundance of these variants was evaluated by a series of overlapping PCR reactions. The size of the most representative cDNA is 3.7 kb and closely agrees with the mRNA size of 3.8 kb determined by Northern blot analysis. The membrane protein encoded contains a leader peptide of 40 residues, a putative extracellular domain of 1003 residues, followed by a hydrophobic segment of 24 residues and a cytoplasmic domain of 49 residues. The extracellular domain was found to contain nine repeating elements, of about 110 residues, which are similar to those of the scavenger receptor superfamily.

Comparison of amylolytic and proteolytic activities of ruminal fungi grown on cereal grains

Strains of the ruminal fungi Neocallimastix patriciarum, Orpinomyces joyonii, and Piromyces communis were grown on cellobiose and on cereal grains and then examined for proteolytic and amylolytic activities. On cellobiose all three fungi displayed similar activities, with the exception of little amylolytic activity in the cell-associated fraction of N. patriciarum. Growth on the cereal grains barley, corn, and wheat showed differences in proteolytic and amylolytic activities amongst the ruminal fungi and between the cereal grains. The data suggest that while these fungi are capable of fermenting the cereal grains the mode of enzymatic attack varies both with the particular fungus and the type of cereal grain.

[The suppressive effect of Tripterygium wilfordii hook F on the IL-2 autocrine loop of human T cells]

We studied the effect of Tripterygium wilfordii Hook F on the IL-2 autocrine loop of human T cells in vitro. The results revealed that GTW significantly inhibited the activation of T cells production of IL-2, expression of IL-2R and proliferation response of activated T cells exogenous IL-2.

Cereal grain digestion by selected strains of ruminal fungi

The ruminal fungi Orpinomyces joyonii strain 19-2, Neocallimastix patriciarum strain 27, and Piromyces communis strain 22 were examined for their ability to digest cereal starch. All strains digested corn starch more readily than barley or wheat starch. Orpinomyces joyonii 19-2 exhibited the greatest propensity to digest starch in wheat and barley, whereas the digestion of these starches by N. patriciarum 27 and P. communis 22 was limited. Media ammonia concentrations were lower when fungal growth was evident, suggesting that all strains assimilate ammonia. Fungi formed extensive rhizoidal systems on the endosperm of corn, but O. joyonii 19-2 was the only strain to form such systems on the endosperm of wheat and barley. All strains penetrated the protein matrix of corn but did not penetrate starch granules. Starch granules from all three cereals were pitted, evidence of extensive digestion by extracellular amylases produced by O. joyonii 19-2. Similar pitting was observed on the surface of corn starch granules digested by N. patriciarum 27 and P. communis 22, but not on wheat and barley starch granules. The ability of ruminal fungi to digest cereal grains depends on both the strain of fungus and the type of grain. The extent to which fungi digest cereal grain in the rumen remains to be determined.

Detection of anti-SSB antibodies in patients with rheumatic diseases

Anti-SSB antibodies were measured by ELISA in patients with various kinds of connective tissue diseases using SSB antigen purified from fresh rabbit thymus. The SSB antigen reacted with anti-SSB standard serum, and the positive rates in SS, SLE, RA, PBS and MCTD were 55.1%, 48.3%, 32.8%, 30.8% and 26.3%, respectively. The titers of anti-SSB antibodies were higher in SS and SLE patients than in other connective tissue disease patients. However, 10% of normal individuals were found to have anti-SSB antibodies with low titers. The anti-SSB antibodies detected were mainly of IgG isotype. Preliminary analysis of clinical data showed no relationship between anti-SSB and systemic involvement in SS.

Efficient DNA transfection of quiescent mammalian cells using poly-L-ornithine

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[The purification of SS-B antigen and detection of anti-SS-B antibodies]

SS-B antigen was purified from fresh rabbit thymus by ammonium sulfate precipitation and column chromatography with Sephadex G100 and phosphocellulose. The M. W. of SS-B is ranged at 41,000 to 48,000. It does not contain the other extractable antigens, like Sm, RNP, PM-ScL, Scl-70, Jo-1, and PCNA. The purified SS-B antigen only reacts with the CDC standard serum of anti-SS-B antigen only reacts with the CDC standard serum of anti-SS-B antibody by ELISA. The positive rate of the antibodies being 55.1%, 48.3%, 32.8%, 30.8% and 26.3% in SS, SLE, RA, PSS and MCTD respectively. The titers of anti-SS-B antibodies were higher in SS and SLE patients than other connective tissue disease patients. It was found that all of the anti-SS-B antibodies detected were mainly of IgG isotype. Preliminary analysis of clinical date shows that there is no relationship between anti-SS-B antibody and systemic involvement in SS.

The glucocorticoid receptor and a putative repressor protein coordinately modulate glucocorticoid responsiveness of the mouse mammary tumor virus promoter in the rat hepatoma cell line M1.19

Signal transduction by glucocorticoid hormones is mediated by the intracellular glucocorticoid receptor protein. The mechanisms determining cell type- or tissue-specific differences in hormone responsiveness remain, however, unclear. To address this issue we have used two different rat hepatoma cell lines, 762 and 6.10.2, respectively, in which mouse mammary tumor virus has been stably integrated. Nuclear extracts from both of these cell lines contained a factor that bound to a sequence motif extending from -163 to -147 in the mouse mammary tumor virus promoter and that appeared to repress hormonal induction of viral mRNA expression. Transient transfection experiments indicated that the cellular levels of this putative repressor did not affect basal promoter activity; this factor appeared rather to determine cellular sensitivity to glucocorticoids. Moreover, in these experiments the relative levels of the glucocorticoid receptor appeared to be the main determinant of maximum inducibility of virus expression by hormone. Taken together, these data indicate that the differential expression patterns of receptor versus the putative repressor protein may determine the level of hormonal responsiveness of target genes in glucocorticoid-sensitive tissues.

[The manifestations of the nervous system in primary Sjogren syndrome]

We reported 9 cases of primary Sjogren syndrome (SS) who were complicated with nervous system involvement. All were women. Age between 24 to 58 years old. Their clinical symptoms of the nervous system varied widely, 7 of them manifested with the involvement of central nervous system, the main features were in case 1 bouts of seizures, case 2 multi-level damage of the brain and spinal cord which was similar to multiple sclerosis, case 3 recurrent hemiplegia caused by cerebral thrombosis then fatal vascular hemorrhage, case 4 sudden hemiplegia, case 5 persistent psychological disturbance, case 6 cranial neuropathy of V and VII, case 9 multi-focal symptoms of ataxia, myelopathy and transient blindness. 5 of the 9, case 3, 6-9 all appeared with the symptoms of peripheral neuropathy, case 7 also complicated with carpal tunnel syndrome. 4 of the 9 cases also complicated with renal tubular acidosis and/or chronic active hepatitis and/or fibrosing alveolitis and/or thrombocytopenic purpura and/or myositis. No differences of the positivity of autoantibodies was observed between those with or without nervous system involvement.