[Advances in the regulation of craniomandibular regeneration by topical application of parathyroid hormone]

Parathyroid hormone (PTH) is a polypeptide molecule synthesized and secreted by parathyroid principal cells. It is an important hormone to maintain the balance of calcium and phosphorus metabolism in the body. It has the dual function of promoting bone formation and bone resorption. In clinic, it promotes osteogenesis by intermittent low-dose subcutaneous injection. In order to avoid the problems of subcutaneous injection, such as poor patient compliance, low utilization of target organs and pain at the injection site, the local application of PTH has attracted much attention in recent years. However, how to realize the local application of PTH and the effect of the local application need to be confirmed by more experiments. This article reviews the local application of PTH and the promotion of jaw regeneration in recent years, in order to provide reference for the local application and research of PTH.

[Interleukin-9 promotes the activation of hepatic stellate cells in mice infected with Schistosoma japonicum]

OBJECTIVE

To investigate the effects of interleukin-9 (IL-9) in the activation of hepatic stellate cells (HSCs) in mice infected with Schistosoma japonicum.

METHODS

Primary HSCs were isolated from mice 7 weeks post-infection with S. japonicum using the in situ liver perfusion and density gradient centrifugation, and cultured in vitro. HSCs were randomly assigned to the PBS control group and IL-9 stimulation group (stimulation with 20 ng/mL IL-9). HSCs were harvested 48 h and 72 h poststimulation, and the expression of α-smooth muscle actin (α-SMA), type I collagen (Col I) and type III collagen (Col III) was determined in HSCs using Western blotting.

RESULTS

Following stimulation with 20 ng/mL IL-9 for 48 h, the expression of α-SMA [(0.87 ± 0.02) vs. (0.69 ± 0.01); t = 17.39, P < 0.01], Col I [(0.74 ± 0.02) vs. (0.65 ± 0.01); t = 9.56, P < 0.01] and Col III [(0.94 ±0.04) vs. (0.75 ± 0.03); t = 6.15, P < 0.01] was significantly greater in HSCs in the IL-9 stimulation group than in the PBS control group. Following stimulation with 20 ng/mL IL-9 for 72 h, the expression of α-SMA was significantly greater in HSCs in the IL-9 stimulation group than in the PBS control group[(0.76 ± 0.02) vs. (0.58 ± 0.02); t = 12.52, P < 0.01]; however, there were no significant differences between the two groups in terms of Col I [(0.68 ± 0.02) vs. (0.66 ± 0.02); t = 1.15, P > 0.05] or Col III expression [(0.75 ± 0.01) vs. (0.72 ± 0.02); t = 2.22, P > 0.05].

CONCLUSIONS

IL-9 promotes the activation of HSCs in mice infected with S. japonicum.

Genistein Modified with 8-Prenyl Group Suppresses Osteoclast Activity Directly via Its Prototype but Not Metabolite by Gut Microbiota

Postmenopausal osteoporosis is a significant threat to human health globally. Genistein, a soy-derived isoflavone, is regarded as a promising anti-osteoporosis drug with the effects of promoting osteoblastogenesis and suppressing osteoclastogenesis. However, its oral bioavailability (6.8%) is limited by water solubility, intestinal permeability, and biotransformation. Fortunately, 8-prenelylated genistein (8PG), a derivative of genistein found in Erythrina Variegate, presented excellent predicted oral bioavailability (51.64%) with an improved osteoblastogenesis effect, although its effects on osteoclastogenesis and intestinal biotransformation were still unclear. In this study, an in vitro microbial transformation platform and UPLC-QTOF/MS analysis method were developed to explore the functional metabolites of 8PG. RANKL-induced RAW264.7 cells were utilized to evaluate the effects of 8PG on osteoclastogenesis. Our results showed that genistein was transformed into dihydrogenistein and 5-hydroxy equol, while 8PG metabolites were undetectable under the same conditions. The 8PG (10^-6 M) was more potent in inhibiting osteoclastogenesis than genistein (10^-5 M) and it down-regulated NFATC1, cSRC, MMP-9 and Cathepsin K. It was concluded that 8-prenyl plays an important role in influencing the osteoclast activity and intestinal biotransformation of 8PG, which provides evidence supporting the further development of 8PG as a good anti-osteoporosis agent.

A new strategy for discovering effective substances and mechanisms of traditional Chinese medicine based on standardized drug containing plasma and the absorbed ingredients composition, a case study of Xian-Ling-Gu-Bao capsules

ETHNOPHARMACOLOGICAL RELEVANCE

The overall therapeutic effect of traditional Chinese medicine formulae (TCMF) was achieved by the interactions of multiple components with multiple targets. However, current pharmacology research strategies have struggled to identify effective substance groups and encountered challenges in elucidating the underlying mechanisms of TCMF.

AIM

In this study, a comprehensive strategy was proposed and applied to elucidate the interactions of the multiple components that underlie the functions of the famous TCMF: Xian-Ling-Gu-Bao (XLGB) capsule on bone metabolism in vivo and to elucidate the molecular mechanisms underlying the effects of XLGB on bone cells, especially on osteoblasts.

METHODS

The efficacy of XLGB in the protection against bones loss in ovariectomized (OVX) rats was confirmed by Micro-CT analysis. The anti-osteoporosis mechanism involved in the systemic regulatory actions of XLGB was elucidated by transcriptome sequencing analysis on bone marrow mesenchymal stem cells isolated from OVX rats. Moreover, the components absorbed in XLGB-treated plasma were characterized by mass spectrometry analysis, and subsequently, a standardized preparation process of drug-containing plasma was established. The synergistic osteogenic effect of the multiple components in plasma was investigated by a combination and then knockout of components using pre-osteoblast MC3T3-E1 cells. In order to decipher the underlying mechanism of XLGB, the targets of the absorbed components on bone were predicted by target prediction and network pharmacology analysis, then several interactions were validated by biochemical and cell-based assay.

RESULTS

A total of 18 genes, including HDC, CXCL1/2, TNF, IL6 and Il1b, were newly found to be the major target genes regulated by XLGB. Interestingly, we found that a combination of the three absorbed components, i.e. MSP, rather than their single form at the same concentration, stimulated the formation of calcified nodules in MC3T3-E1 cells, suggesting a synergistic effect of these components. Besides, target prediction and experimental validation confirmed the binding affinity of corylin and icaritin for estrogen receptor α and β, the inhibitory activity of isobavachin and isobavachalcone on glycogen synthase kinase-3β, and the inhibitory activity of isobavachalcone on cathepsin K. The cell-based assay further confirmed the result of the biochemical assay. A network that integrated absorbed components of XLGB-targets-perturbation genes-pathways against osteoporosis was established.

CONCLUSION

Our current study provides a new systemic strategy for discovering active ingredient groups of TCM formulae and understanding their underlying mechanisms.

A novel strategy for exploring food originated anti-adipogenesis substances and mechanism by structural similarity evaluation, ADME prediction, network pharmacology and experimental validation

Screening potential functional substances based on active compounds is still a challenge faced by researchers since hundreds and thousands of possible compounds exist in natural products (food, herb, etc.). In this study, an integrated strategy by a combination of structural similarity evaluation, ADME (absorption, distribution, metabolism, excretion) prediction, network pharmacology and experimental validation (SANE strategy) was proposed and applied to explore anti-adipogenesis substances. This strategy was divided into four parts: first, potential compounds were screened based on representative active compounds by similarity evaluation and ADME prediction. Second, the activity of targeted compounds was evaluated in vitro based on the molecular biology method. Third, network pharmacology was used to explore potential targets and pathways. Last, the core pharmacological mechanism was confirmed by modern pharmacology methods. As a result, 8-prenylgenistein (8PG) was screened with chemical structure similarity with genistein and improved ADME propriety. Meanwhile, 8PG was found to present significant anti-adipogenesis effects in pre-adipocyte 3T3-L1 cells and primary human bone marrow stromal cells (hBMSC). Through using methods including: chemical staining, functional assays, and Real time PCR, 8PG was found to present more potency than genistein in suppressing the adipocyte differentiation. Further, the potential pharmacological mechanism was predicted, and significant effects of 8PG on activating the Wnt/β-catenin pathway in 3T3-L1 cells and hBMSC were confirmed by  immunoblotting in the absence/presence of signaling pathway blocker and immunofluorescence staining. A new insight for exploring more potent compounds based on accurate effect compounds is provided in our work. Moreover, a potential compound (8PG), suppressing adipogenesis, was also supplied.

[Expression of osteoprotegerin and receptor activator of nuclear factor kappa-B ligand in mandibular ramus osteotomy healing with administration of different doses of parathyroid hormone]

Objective: To investigate the effect of parathyroid hormone (PTH) on the bone healing of mandibular ramus osteotomy. Methods: The mandibular ramus osteotomy model was established in sixty rabbits and these rabbits were randomly divided into experimental group A, experimental group B and control group. In the experimental group A and experimental group B, the rabbits were given PTH (20 and 40 μg/kg respectively) every other day after operation. In the control group, 1 ml saline was given. The animals were sacrificed at 1 week, 2 weeks, 3 weeks and 4 weeks postoperatively. The new bone formation was observed by histology and cone bone CT. The expression of osteoprotegerin and receptor activator of nuclear factor kappa-B (RANKL) in the new bone was detected by real-time quantitative PCR. Results: The experimental groups has better osteogenesis and the bone mineral density than the control group in osteotomy area. The experimental group B showed the best osteogenesis.Osteoprotegerin mRNA expression in experimental group A (1.127±0.035, 1.742±0.049, 1.049±0.062, 1.063±0.036) was significantly higher than that in the control group in each period (0.965±0.082, 1.254±0.071, 0.793±0.061, 0.684±0.055) (P=0.010, P=0.000, P=0.001, P=0.020), while group B (1.416±0.205, 2.648±0.168, 1.652±0.091, 1.712±0.070) was significantly higher than group A (P=0.000, P=0.010, P=0.023, P=0.003). RANKL mRNA expression in control group (1.666±0.086, 1.058±0.105, 0.885±0.124, 0.972±0.136) was significantly higher than that of the group A (0.788±0.036, 0.585±0.017, 0.692±0.017, 0.527±0.051) (P=0.001, P=0.006, P=0.003, P=0.028) in each period, while group A was significantly higher than group B(0.247±0.022, 0.240±0.034, 0.134±0.011, 0.103±0.050) (P=0.000, P=0.001, P=0.002, P=0.012). Conclusions: PTH can upregulate the expression of osteoprotegerin and reduce expression of RANKL, thus promoting new bone formation. Intermittent administration of high dose of parathyroid hormone can further promote the healing process after mandibular ramus osteotomy.

[The progress in application of parathyroid hormone in craniomaxillofacial bone regeneration study]

Parathyroid hormone(PTH)is synthesized and secreted by chief cell of Gley's glands which possesses dual functions of catabolism and anabolism. It regulates the proliferation and differentiation of multiple cell lines including osteoblast, osteoclast and skeletal lining cells. Furthermore, PTH activates various signaling pathways which control calcium, phosphorous' metabolism and bone conversion, accelerating the bone regeneration and reconstruction. However, the study of PTH in craniomaxillofacial bone regeneration is relatively less and whether the role of parathyroid glands and the mechanism of ossification are consistent with the long bone or not needs further investigation. This review focuses on the progress of PTH in craniomaxillofacial bone regeneration in recent years.

Expression and SNP association analysis of porcine FBXL4 gene

As a kind of E3 ligase, the product of FBXL4 gene belongs to a member of FBLs which is the biggest eukaryotic subfamily of F-BOX proteins, it can recognize some substrate through particular protein-protein interaction domains. To investigate its functions, the polymorphism and association analysis was analyzed. The partial cDNA of porcine FBXL4 with 2384 bp long was first cloned; the deduced protein comprises a conserved F-BOX domain at position from the 277th to 332nd amino acid. The phylogenetic tree indicated porcine FBXL4 has the closest genetic relationship with bovine FBXL4 than other selected animal species. Ten tissue expression level of porcine FBXL4 mRNA fluctuated remarkably in a large range by quantitative RT-PCR analysis. For two identified SNPs, the genotyping analysis of Tail showed TT genotype owned dominance in introduced Landrace pig and miniature Guizhou and Wuzhishan breeds, but CC genotype was more than two other genotypes in miniature Laiwu breed. While in another genotyping analysis of BsaJI, CC genotype was obviously more than other genotypes in two kinds of Chinese miniature pig breeds and introduced Landrace pig breeds. Furthermore, the association analysis with immune traits and blood parameters revealed that SNP Tail was significantly associated with the lymphocyte percentage (P = 0.0166) and the antibody levels for pseudorabies virus vaccination (P = 0.0001) of neonate piglets at 0 day. Meanwhile, SNP BsaJI was significantly associated with lymphocyte percentage of individuals at 32 days (P = 0.0351), neutrophil percentage (P = 0.0005), the absolute lymphocyte count (P = 0.0458), and the mixed cells (P = 0.0010) of neonate piglets at 0 day.

Molecular characterization and association analysis of FBXO40 with partial hematological indexes in pig

F-box proteins are quite significant ubiquitin-proteasome pathway regulators in eukaryotic cells. FBXO40, a member of this large family, alters its expression pattern in muscle atrophy. Here we isolated most of the verified porcine FBXO40 coding sequence (CDS) (2258 bp) and assigned it to the porcine chromosome 13q4.1-4.6 by using the INRA-Minnesota porcine radiation hybrid panel, and we also explored the tissue expression distributions, which is relatively high in longissimus dorsi muscle, heart, low in kidney, small intestine, brain, hypophysis, lymphonode, thymus, spleen, large intestine, ovary, stomach, and undetectable in testis, liver, uterus and thyroid gland. Inferring phylogenetic tree was constructed to study the evolutionary implications. Moreover, a HindII (HincII)-RFLP (A/C) polymorphism in 3'-untranslated region (3'-UTR) of porcine FBXO40 gene was demonstrated by sequencing and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. Statistical analysis result of this polymorphism showed that the allele A was predominant in all detected indigenous breeds, but C in western introduced commercial breeds. The SNP was further analyzed in our experimental pig population including Tongcheng, Landrace, Large White, and crossbreds of Large White × (Landrace × Tongcheng) and Landrace × (Large White × Tongcheng). The association analysis results indicated that the A/C base substitution was associate with some hematological indexes, the hemoglobin concentration (P < 0.0001), mean corpuscular volume hemoglobin concentration (P = 0.0002) and mean corpuscular volume (P = 0.0138).

Survey on the function, structure and operation of hospital ethics committees in Shanghai

OBJECTIVE

The objectives of this study are to understand the current functions, structure and operation of hospital ethics committees (HECs) in Shanghai and to facilitate their improvement.

METHODS

(1) A questionnaire survey, (2) interviews with secretaries and (3) on-site document reviews of HECs in Shanghai were used in the study, which surveyed 33 hospitals.

RESULTS

In Shanghai, 57.56% of the surveyed hospitals established HECs from 1998 to 2005. Most HECs used bioethical review of research involving human subjects as well as bioethical review or consultation regarding medical care services and administrative decision- making. Of the surveyed HECs, 14.3% did not provide any formal bioethical training to the HECs' members and many HECs had no standard operating procedures. Some HECs had no clear definition of what was "conflict of interest" that should be considered by the HECs, while 44.4% of the HECs did not perform continuing review.

DISCUSSION

After the issues of related national regulations, more and more hospitals established HECs in Shanghai, but the functions of HECs need to be further developed and formal training on bioethics should be provided to HEC members. To assure the independence and good performance of HECs, the conflict of interest procedure, the standard operating procedures and bioethical review should be improved.

CONCLUSION

HECs in Shanghai had developed in the preceding 10 years and they played great roles in protecting the rights and welfare of human subjects and patients; some areas need improvement.

Partial molecular characterization, expression pattern, polymorphism and association analysis of porcine SKP2 gene

As a component of E3 ubiquitin protein ligases called SCFs, SKP2 protein belongs to a member of FBLs protein which is the biggest eukaryotic subfamily of F-BOX proteins with 12 members. In this study, we cloned and sequenced partial cDNA, intron 1 and intron 6 of porcine SKP2 gene. The partial cDNA is 1,402 bp long and has an open reading frame of 1,272 bp which encodes 424 putative amino acids. The deduced protein comprises a conserved F-BOX domain at position from the 90th to 140th amino acid. The phylogenetic tree indicated that porcine SKP2 has the closest genetic relationship with bovine SKP2 than other selected animal species. Quantitative RT-PCR analysis displayed that the tissue expression level of porcine SKP2 fluctuated remarkably in a large range, and it expressed in thymus with the highest level and in longissimus dorsi muscle with the lowest level. Two SNPs were identified, meanwhile, further polymorphism analysis with Cfr42I showed that AA genotype was in dominance absolutely among four kinds of unrelated Chinese indigenous miniature and one introduced Landrace pig breeds. In addition, association analysis with immune traits and blood parameters revealed that the SNP Cfr42I in intron 1 was significantly associated with red cell distribution width of neonate piglets at 0 day (P = 0.027).

Full-length coding sequences, polymorphism and chromosomal localizations of the porcine EDG4 and EDG7 genes

EDG4 and EDG7 are identified as cellular receptors for lysophosphatidic acid (LPA), belonging to the endothelial cell differentiation gene (EDG) family of G protein-coupled receptors (GPCR) which play an important role in the function of LPA. In this study, we presented the complete coding sequences of porcine EDG4 and EDG7 genes. The nucleotide sequences and the predicted protein sequences share high sequence identity with other mammals. Spatial expression analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that porcine EDG4 and EDG7 genes are mainly expressed in brain, liver, spleen, lung, kidney, large intestine, small intestine, but absent in muscle tissues. Radiation hybrid mapping data indicated that EDG4 and EDG7 map to q2.1 of pig chromosome 2 (SSC2) and q2.6-3.2 of pig chromosome6 (SSC6), respectively. A T/C single nucleotide polymorphism (SNP) in the coding sequence of porcine EDG4 was identified. A PCR-restriction fragment length polymorphism (PCR-RFLP) method was employed to genotype this locus among Guizhou Miniature, Guangxi Miniature, Laiwu, Wuzhishan, Tongcheng, Landrace and Yorkshire pigs. The association analysis suggested that the EDG4 genotype was associated with carcass length (P < 0.05) and drip loss percentage (P < 0.05) in the experimental population consisting of Tongcheng, Landrace, Yorkshire and two crossbred porcine populations (Wang et al. Biochem Genet (1-2):51-62, 2007).

Role of zinc in pulmonary endothelial cell response to oxidative stress

Although zinc is a well-known inhibitor of apoptosis, it may contribute to oxidative stress-induced necrosis. We noted that N,N,N',N'- tetrakis(2-pyridylmethyl)ethylenediamine (TPEN; >10 microM), a zinc chelator, quenched fluorescence of the zinc-specific fluorophore Zinquin and resulted in an increase in spontaneous apoptosis in cultured sheep pulmonary artery endothelial cells (SPAECs). Addition of exogenous zinc (in the presence of pyrithione, a zinc ionophore) to the medium of SPAECs caused an increase in Zinquin fluorescence and was associated with a concentration-dependent increase in necrotic cell death. Exposure of SPAECs to TPEN (10 microM) resulted in enhanced apoptosis after lipopolysaccharide or complete inhibition of t-butyl hydroperoxide (tBH)-induced necrosis. We further investigated the role of two zinc-dependent enzymes, poly(ADP-ribose) polymerase (PARP) and protein kinase (PK) C, in tBH toxicity. tBH toxicity was only affected by the PARP inhibitors 4-amino-1,8-naphthalimide or 3-aminobenzamide over a narrow range, whereas the PKC inhibitors bisindolylmaleimide and staurosporine significantly reduced tBH toxicity. tBH caused translocation of PKC to the plasma membrane of SPAECs that was partially inhibited by TPEN. Thus pulmonary endothelial cell zinc inhibits spontaneous and lipopolysaccharide-dependent apoptosis but contributes to tBH-induced necrosis, in part, via a PKC-dependent pathway.

Actin-containing sera from patients with adult respiratory distress syndrome are toxic to sheep pulmonary endothelial cells

Actin released from damaged cells after a variety of tissue injuries appears to be involved in multiple organ dysfunction syndrome. Under experimental conditions, when the quantity of actin present in plasma is made to exceed the protective capacity of the actin-scavenging mechanism, microembolism and pulmonary vascular angiopathy have been noted in rats. It remains to be determined whether this injury is a result of a direct toxic effect or occurs indirectly via platelet activation or fibrin interactions. We examined the effect of sera from patients with adult respiratory distress syndrome (ARDS), as well as G-actin added to normal serum, on the viability, morphology, and function of cultured sheep pulmonary artery endothelial cells (SPAEC). Both patient sera and normal sera to which actin was added were toxic in the cell culture model; this toxicity could be abrogated, at least partially, by preincubation with gelsolin, which is known to complex with actin. A significant portion of the toxicity of sera from patients with ARDS was sensitive to heat (56 degrees C), suggesting an important role of complement. Sera from patients with ARDS were shown to contain filaments of F-actin by immunoblot and rhodamine phalloidin staining after ultracentrifugation. Thus, saturation of the actin-scavenging system by addition of exogenous G-actin to plasma produces direct pulmonary endothelial cell injury. Furthermore, plasma from patients with ARDS secondary to bacterial pneumonia is toxic to SPAEC, and a small but significant contributory role of actin is apparent in these studies.

Involvement of capsaicin-sensitive sensory nerves in early and delayed cardioprotection induced by a brief ischaemia of the small intestine

Early cardioprotection can be achieved by a brief ischaemia of noncardiac tissues. Our study examined whether a brief ischaemia of the small intestine induces both early and delayed cardioprotection in the rabbit and assessed the possible mechanism involved in the activation of capsaicin-sensitive sensory nerves. The plasma concentration of creatine kinase (CK) and infarct size (necrotic zone/left ventricular zone) after 30 min coronary artery occlusion and 180 min reperfusion were determined in rabbits. Infarct size was 35.5+/-6.8% in the control non-preconditioned group. Preconditioning induced by a brief period of 10-min small intestine ischaemia significantly reduced infarct size (6.5+/-1.9%, P<0.01 vs. the control non-preconditioned group) and decreased CK release (3092+/-236 and 1094+/-117 U/l for myocardial ischaemia-reperfusion and preconditioning plus myocardial ischemia-reperfusion, respectively, P<0.01), and the protection was partly abolished by pretreatment with capsaicin (50 mg/kg, s.c.) 4 days before the experiments. A brief period of anterior mesenteric artery occlusion caused an increase in the plasma level of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI), an effect which was abolished by pretreatment with capsaicin. Similar protection was shown in the animals subjected to a brief period of anterior mesenteric artery occlusion 24 h before coronary artery occlusion, and this delayed protection was also abolished partly by pretreatment with capsaicin. Capsaicin treatment (50 mg/kg, s.c.) alone also protected the ischaemic myocardium. The results suggest that brief ischaemia of the small intestine induces both early and delayed protection against reperfusion-induced myocardial injury, and the effects are, at least partly, related to the activation of capsaicin-sensitive sensory nerves.

Influence of endothelium on responses of isolated dog coronary artery to beta-adrenoceptor agonists

AIM

To study the role of the endothelium in mediating the response of the coronary arteries to adrenoceptor agonists.

METHODS

Endothelium intact and denuded dog epicardial coronary artery rings were used. The contractile responses were recorded on forcetransducer and a pen recorder.

RESULTS

In all ring segments, norepinephrine (NE) and isoproterenol (Iso) produced concentration-dependent relaxation in the presence and absence of phentolamine. Endothelium-removal decreased this relaxation and depressed the maximal response. Inhibition of nitric oxide synthesis by N omega-nitro-L-arginine-methyl ester induced the same influences as endothelium-removal.

CONCLUSION

beta-adrenoceptor agonists produce relaxation of dog coronary artery by both endothelium-dependent and independent mechanisms, endothelium-dependent relaxation induced by beta-adrenoceptor agonists is mediated by nitric oxide.

The primary sequence of murine caveolin reveals a conserved consensus site for phosphorylation by protein kinase C

We report here the cloning of the murine cDNA encoding caveolin, a known v-Src substrate and caveolar marker protein. Interestingly, analysis of the murine cDNA and comparison with caveolin from other species reveals a previously unrecognized consensus site for protein kinase C (PKC) phosphorylation. This finding could have important implications as (i) both the morphology and function of caveolae are dramatically affected by PKC activators; and (ii) PKC alpha is concentrated in isolated caveolin-rich membrane domains. In addition, this first step should facilitate the use of the mouse as a genetic system for elucidating the role of caveolin in caveolar functioning.

Protection of bradykinin on neonatal rat myocytes subjected to anoxia/reoxygenation injury

This study was to investigate the effects of bradykinin (BK) on myocyte cultures. The effects of BK against lipid peroxidation and oxygen free radicals were estimated on an anoxia/reoxygenation injured model. A salicylate hydroxylation product dihydroxybenzoic acids (DHBA) was detected using HPLC with electrochemical detection, a sensitive device for assaying the hydroxyl free radical. BK (10 nmol.L-1) reduced thiobarbituric acid reactive substances (TBARS, from 1.94 +/- s 0.28 to 0.25 +/- 0.03 nmol/10(6) cells, n = 5, P < 0.01), lactate dehydrogenase (LDH) release (1.28 +/- 0.23 to 0.63 +/- 0.12 u.ml-1, n = 8, P < 0.01) and DHBA (60 +/- 5 to 44 +/- 12 nmol.L-1, n = 6, P < 0.01). These improvements were nullified by pretreatment with K86/4321 (1 mumol.L-1), a kind of BK receptor antagonist. Indometacin (Ind, 1 mumol.L-1) had a synergic action with BK to decrease the LDH release, but Ind (30 mumol.L-1) attenuated the protection of BK, while both LDH and TBARS were increased. The mechanism for protection of BK was ascribable to the activation of BK receptor, the inhibition of lipid peroxidation, and the decreased hydroxyl free radical formation.

In vitro phosphorylation of caveolin-rich membrane domains: identification of an associated serine kinase activity as a casein kinase II-like enzyme

Caveolae are flask-shaped micro-invaginations associated with the plasma membrane of a wide variety of cell types. Caveolin, an integral membrane component of caveolae, was first identified as the major phosphoprotein whose phosphorylation was elevated in v-Src transformed cells. As both v-Src transformation and elevated caveolin phosphorylation were dependent on membrane attachment of v-Src, it has been suggested that caveolin is a critical target in v-Src transformation. Although an increase in tyrosine phosphorylation of caveolin was evident, the increase in caveolin phosphorylation was predominantly on serine residues. In accordance with these in vivo observations, isolated caveolin-rich membrane domains undergo phosphorylation in vitro predominantly on serine and contain an unidentified serine kinase activity. Here, we have identified this serine kinase activity as a casein kinase II-like enzyme, since the phosphorylation of caveolin-rich membrane domains is stimulated and inhibited by known effectors of casein kinase II (poly-L-lysine, endogenous polyamines, and a casein kinase II inhibitor peptide), but is unaffected by modulators of other known kinases. In support of these observations, caveolin contains a consensus sequence for casein kinase II phosphorylation in its cytoplasmic N-terminal domain (Ser-88). A peptide containing this sequence inhibits the in vitro phosphorylation of caveolin-rich membrane domains, while many other peptides derived from the N-terminal domain of caveolin do not affect phosphorylation. Caveolin-rich membrane domains were also a substrate for exogenously added purified casein kinase II, but not casein kinase I. Finally, immunoblotting of these domains with an antibody directed against the alpha and alpha' subunits of casein kinase II reveals two bands with apparent molecular weights consistent with the known molecular weights of the alpha and alpha' subunits of casein kinase II. As casein kinase II appears to play a role in mitogenic signalling events and casein kinase II activators (endogenous polyamines) are required for v-Src transformation, our results may have implications for understanding the mechanism of v-Src oncogenesis.

Caveolin forms a hetero-oligomeric protein complex that interacts with an apical GPI-linked protein: implications for the biogenesis of caveolae

Glycosyl-phosphatidylinositol (GPI)-linked proteins are transported to the apical surface of epithelial cells where they undergo cholesterol-dependent clustering in membrane micro-invaginations, termed caveolae or plasmalemmal vesicles. However, the sorting machinery responsible for this caveolar-clustering mechanism remains unknown. Using transfected MDCK cells as a model system, we have identified a complex of cell surface molecules (80, 50, 40, 22-24, and 14 kD) that interact in a pH- and cholesterol-dependent fashion with an apical recombinant GPI-linked protein. A major component of this hetero-oligomeric protein complex is caveolin, a type II transmembrane protein. As this hetero-oligomeric caveolin complex is detectable almost immediately after caveolin synthesis, our results suggest that caveolae may assemble intracellularly during transport to the cell surface. As such, our studies have implications for understanding both the intracellular biogenesis of caveolae and their subsequent interactions with GPI-linked proteins in epithelia and other cell types.

[A study of Laminaria digitata powder on experimental hyperlipoproteinemia and its hemorrheology]

Twenty rabbits with experimental hyperlipoproteinemia were divided randomly into two groups. The first group was administered Laminaria digitata powder (1 g daily) for 14 days. Another was given only the routine menu. It was found that the Laminaria digitata had a significant effect of lowering total cholesterol, -lipoprotein, especially triglyceride (P less than 0.01), meanwhile it could increase the level of HDL-c and HDL2-c. Also it could reduce relative blood viscosity, relative plasma viscosity, reductive viscosity and fibrinogen very significantly (P less than 0.01). However HDL3-c, hematocrit and index of erythrocytic deformability were not much influenced (P greater than 0.05). This experiment showed that there was a connection between the blood lipids and the concept of "Phlegm" in TCM.