[Diagnosis and treatment of strabismus caused by nasal endoscopic surgery]

Objective: Strabismus with diplopia is the main orbital complication of functional endoscopic sinus surgery (FESS). This study was to analyze clinical findings, treatment and outcomes of such cases. Methods: Retrospective case series. Twenty-three cases were divided into 3 groups based on the disease severity: group A, partial transection of the medial rectus muscle, group B, complete transection of the medical rectus, group C, transection of the medial rectus combined with the other orbital injuries. Complete ophthalmology examinations, including eye alignment, eye motility, force duction test, force generation test, general eye exam, and medical imaging (orbital CT or MRI), were performed for each case. The treatment included botulinum toxin (Botox) injection to the lateral rectus muscle, transposition of the vertical rectus muscle, and orbital surgery if needed. Results: In group A with Botox injection, all the cases achieved single vision in primary position, but still remained some adduction weakness. In group B treated by vertical transposition surgery combined with Botox, 22% of the cases got single vision in primary gaze. In group C, even with more efforts of treatment, the cases with orbital injury can only get cosmetic improvement, and diplopia and adduction dysfunction were found in most cases. Conclusions: Due to the variety of the complications of FESS, force duction test is a crucial exam to detect the direction and severity of synechia in the orbit, which will give solid information to surgery approach as well as prognosis. Botox injection at early stage will minimize the contraction of antagonist lateral rectus, helping to postpone the transposition surgery which may cause anterior segment ischemia when performed right after the medial rectus transection injury. Botox may even reduce the synechia by minimizing the scarring process. Partial vertical rectus transposition combined with muscle resection may effectively correct the eye misalignment in primary gaze and improve eye motility. The prognosis of FESS induced orbital complications is quite related with the severity of the injury. Botox combined with surgery may help medial rectus transection cases to achieve single vision in primary gaze, but when there is any other orbital injury, treatment may only improve cosmetic appearance. (Chin J Ophthalmol, 2017, 53: 917-923).

A comprehensive analysis of the dual roles of BMPs in regulating adipogenic and osteogenic differentiation of mesenchymal progenitor cells

Pluripotent mesenchymal stem cells (MSCs) are bone marrow stromal progenitor cells that can differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. Several signaling pathways have been shown to regulate the lineage commitment and terminal differentiation of MSCs. Here, we conducted a comprehensive analysis of the 14 types of bone morphogenetic protein (BMPs) for their abilities to regulate multilineage specific differentiation of MSCs. We found that most BMPs exhibited distinct abilities to regulate the expression of Runx2, Sox9, MyoD, and PPARgamma2. Further analysis indicated that BMP-2, BMP-4, BMP-6, BMP-7, and BMP-9 effectively induced both adipogenic and osteogenic differentiation in vitro and in vivo. BMP-induced commitment to osteogenic or adipogenic lineage was shown to be mutually exclusive. Overexpression of Runx2 enhanced BMP-induced osteogenic differentiation, whereas knockdown of Runx2 expression diminished BMP-induced bone formation with a decrease in adipocyte accumulation in vivo. Interestingly, overexpression of PPARgamma2 not only promoted adipogenic differentiation, but also enhanced osteogenic differentiation upon BMP-2, BMP-6, and BMP-9 stimulation. Conversely, MSCs with PPARgamma2 knockdown or mouse embryonic fibroblasts derived from PPARgamma2(-/-) mice exhibited a marked decrease in adipogenic differentiation, coupled with reduced osteogenic differentiation and diminished mineralization upon BMP-9 stimulation, suggesting that PPARgamma2 may play a role in BMP-induced osteogenic and adipogenic differentiation. Thus, it is important to understand the molecular mechanism behind BMP-regulated lineage divergence during MSC differentiation, as this knowledge could help us to understand the pathogenesis of skeletal diseases and may lead to the development of strategies for regenerative medicine.

Hey1 basic helix-loop-helix protein plays an important role in mediating BMP9-induced osteogenic differentiation of mesenchymal progenitor cells

Pluripotent mesenchymal stem cells (MSCs) are bone marrow stromal progenitor cells that can differentiate into osteogenic, chondrogenic, adipogenic, and myogenic lineages. We previously demonstrated that bone morphogenetic protein (BMP) 9 is one of the most potent and yet least characterized BMPs that are able to induce osteogenic differentiation of MSCs both in vitro and in vivo. Here, we conducted gene expression-profiling analysis and identified that Hey1 of the hairy/Enhancer of split-related repressor protein basic helix-loop-helix family was among the most significantly up-regulated early targets in BMP9-stimulated MSCs. We demonstrated that Hey1 expression was up-regulated at the immediate early stage of BMP9-induced osteogenic differentiation. Chromatin immunoprecipitation analysis indicated that Hey1 may be a direct target of the BMP9-induced Smad signaling pathway. Silencing Hey1 expression diminished BMP9-induced osteogenic differentiation both in vitro and in vivo and led to chondrogenic differentiation. Likewise, constitutive Hey1 expression augmented BMP9-mediated bone matrix mineralization. Hey1 and Runx2 were shown to act synergistically in BMP9-induced osteogenic differentiation, and Runx2 expression significantly decreased in the absence of Hey1, suggesting that Runx2 may function downstream of Hey1. Accordingly, the defective osteogenic differentiation caused by Hey1 knockdown was rescued by exogenous Runx2 expression. Thus, our findings suggest that Hey1, through its interplay with Runx2, may play an important role in regulating BMP9-induced osteoblast lineage differentiation of MSCs.

Osteogenic BMPs promote tumor growth of human osteosarcomas that harbor differentiation defects

Osteosarcoma (OS) is the most common primary malignancy of bone. Here, we investigated a possible role of defective osteoblast differentiation in OS tumorigenesis. We found that basal levels of the early osteogenic marker alkaline phosphatase (ALP) activity were low in OS lines. Osteogenic regulators Runx2 and OSX, and the late marker osteopontin (OPN) expressed at low levels in most OS lines, indicating that most OS cells fail to undergo terminal differentiation. Furthermore, OS cells were refractory to osteogenic BMP-induced increases in ALP activity. Osteogenic BMPs were shown to upregulate early target genes, but not late osteogenic markers OPN and osteocalcin (OC). Furthermore, osteogenic BMPs failed to induce bone formation from human OS cells, rather effectively promoted OS tumor growth in an orthotopic OS model. Exogenous expression of early target genes enhanced BMP-stimulated OS tumor growth, whereas osteogenic BMP-promoted OS tumor growth was inhibited by exogenous Runx2 expression. These results suggest that alterations in osteoprogenitors may disrupt osteogenic differentiation pathway. Thus, identifying potential differentiation defects in OS tumors would allow us to reconstruct the tumorigenic events in osteoprogenitors and to develop rational differentiation therapies for clinical OS management.

BMP-9-induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/beta-catenin signalling

Bone morphogenetic protein 9 (BMP-9) is a member of the transforming growth factor (TGF)-beta/BMP superfamily, and we have demonstrated that it is one of the most potent BMPs to induce osteoblast differentiation of mesenchymal stem cells (MSCs). Here, we sought to investigate if canonical Wnt/beta-catenin signalling plays an important role in BMP-9-induced osteogenic differentiation of MSCs. Wnt3A and BMP-9 enhanced each other's ability to induce alkaline phosphatase (ALP) in MSCs and mouse embryonic fibroblasts (MEFs). Wnt antagonist FrzB was shown to inhibit BMP-9-induced ALP activity more effectively than Dkk1, whereas a secreted form of LPR-5 or low-density lipoprotein receptor-related protein (LRP)-6 exerted no inhibitory effect on BMP-9-induced ALP activity. beta-Catenin knockdown in MSCs and MEFs diminished BMP-9-induced ALP activity, and led to a decrease in BMP-9-induced osteocalcin reporter activity and BMP-9-induced expression of late osteogenic markers. Furthermore, beta-catenin knockdown or FrzB overexpression inhibited BMP-9-induced mineralization in vitro and ectopic bone formation in vivo, resulting in immature osteogenesis and the formation of chondrogenic matrix. Chromatin immunoprecipitation (ChIP) analysis indicated that BMP-9 induced recruitment of both Runx2 and beta-catenin to the osteocalcin promoter. Thus, we have demonstrated that canonical Wnt signalling, possibly through interactions between beta-catenin and Runx2, plays an important role in BMP-9-induced osteogenic differentiation of MSCs.

Characterization of gene expression regulated by American ginseng and ginsenoside Rg3 in human colorectal cancer cells

American ginseng (Panax quinquefolius L., Araliaceae) possesses anti-cancer potential and is one of the most commonly used herbal medicines in the United States. Ginsenoside Rg3, one of the saponins in American ginseng, has been shown to inhibit tumor growth. In this study, we sought to characterize the downstream genes targeted by American ginseng extracts in HCT-116 human colorectal cancer cells. We first demonstrated that the content of Rg3 in American ginseng steamed at 120 degrees C for 2 h (referred to as S2h) was significantly increased when compared with that of the unsteamed ginseng. Both S2h and Rg3 exhibited antiproliferative effects on HCT-116 cells. Using the Affymetrix high density genechips containing more than 40,000 genes and ESTs, the gene expression profiling of HCT-116 cells were assayed. Microarray data indicated that the expression levels of 76 genes were changed significantly after treatment with S2h or Rg3, whereby it was found that 52 of the 76 genes were up-regulated while the remaining 24 were down-regulated. Ingenuity pathways analysis of top functions affected by both S2h and Rg3 were carried out. The most effected pathway is the Ephrin receptor pathway. To validate the microarray data, quantitative real-time PCR of six candidate target genes was conducted, whereby it was found that three genes were up-regulated (AKAPA8L, PMPCB and PDE5A) and three were down-regulated (PITPNA, DUS2L and RIC8A). Although further studies are needed to elucidate the mechanisms of action, our findings should expand the understanding of the molecular framework of American ginseng as an anti-cancer agent.

A protocol for rapid generation of recombinant adenoviruses using the AdEasy system

Recombinant adenoviruses provide a versatile system for gene expression studies and therapeutic applications. We have developed an approach that simplifies the generation and production of such viruses called the AdEasy system. A recombinant adenoviral plasmid is generated with a minimum of enzymatic manipulations, employing homologous recombination in bacteria rather than in eukaryotic cells. After transfection of such plasmids into a mammalian packaging cell line, viral production is conveniently followed with the aid of GFP encoded by a gene incorporated into the viral backbone. This system has expedited the process of generating and testing recombinant adenoviruses for a variety of purposes. In this protocol, we describe the practical aspects of using the AdEasy system for generating recombinant adenoviruses. The full protocol usually takes 4-5 weeks to complete.

Regulation of osteogenic differentiation during skeletal development

Bone formation during skeletal development involves a complex coordination among multiple cell types and tissues. Bone is of crucial importance for the human body, providing skeletal support, and serving as a home for the formation of hematopoietic cells and as a reservoir for calcium and phosphate. Bone is also continuously remodeled in vertebrates throughout life. Osteoblasts and osteoclasts are specialized cells responsible for bone formation and resorption, respectively. Early development of the vertebrate skeleton depends on genes that control the distribution and proliferation of cells from cranial neural crest, sclerotomes, and lateral plate mesoderm into mesenchymal condensations, where cells differentiate to osteoblasts. Significant progress has been made over the past decade in our understanding of the molecular framework that controls osteogenic differentiation. A large number of morphogens, signaling molecules, and transcriptional regulators have been implicated in regulating bone development. A partial list of these factors includes the Wnt/beta-catenin, TGF-beta/BMP, FGF, Notch and Hedgehog signaling pathways, and Runx2, Osterix, ATF4, TAZ, and NFATc1 transcriptional factors. A better understanding of molecular mechanisms behind osteogenic differentiation would not only help us to identify pathogenic causes of bone and skeletal diseases but also lead to the development of targeted therapies for these diseases.

Distinct roles of bone morphogenetic proteins in osteogenic differentiation of mesenchymal stem cells

Efficacious bone regeneration could revolutionize the clinical management of many bone and musculoskeletal disorders. Bone morphogenetic proteins (BMPs) can regulate the differentiation of mesenchymal stem cells into cartilage, bone, tendon/ligament, and fat lineages. Early data documented the osteogenic potential of rhBMP2 and rhBMP7/OP-1. However, prior to this work that summarized several of our recent studies, no comprehensive analysis had been undertaken to characterize relative osteogenic activity of all BMPs. Using recombinant adenoviruses expressing 14 BMPs, we have demonstrated that, besides BMP2 and BMP7, BMP6 and BMP9 exhibit the highest osteogenic activity both in vitro and in vivo. We further demonstrated that several BMPs may exert synergistic effect on osteogenic differentiation, and that osteogenic BMPs produce a distinct set of molecular fingerprints during osteogenic differentiation. The reported work should expand our current understanding of BMP functions during osteogenic differentiation. It is conceivable that osteogenic BMPs (i.e., BMP2, 4, 6, 7, and 9) may be used to formulate synergistic pairs among themselves and/or with other less osteogenic BMPs for efficacious bone regeneration in clinical settings.

Selection and validation of optimal siRNA target sites for RNAi-mediated gene silencing

RNA interference (RNAi)-mediated gene silencing has become a valuable tool for functional studies, reverse genomics, and drug discoveries. One major challenge of using RNAi is to identify the most effective short interfering RNAs (siRNAs) sites of a given gene. Although several published bioinformatic prediction models have proven useful, the process to select and validate optimal siRNA sites for a given gene remains empirical and laborious. Here, we developed a fluorescence-based selection system using a retroviral vector backbone, namely pSOS, which was based on the premise that candidate siRNAs would knockdown the chimeric transcript between GFP and target gene. The expression of siRNA was driven by the opposing convergent H1 and U6 promoters. This configuration simplifies the cloning of duplex siRNA oligonucleotide cassettes. We demonstrated that GFP signal reduction was closely correlated with siRNA knockdown efficiency of human beta-catenin, as well as with the inhibition of beta-catenin/Tcf4 signaling activity. The pSOS should not only facilitate the selection and validation of candidate siRNA sites, but also provide efficient delivery tools of siRNAs via viral vectors in mammalian cells. Thus, the pSOS system represents an efficient and user-friendly strategy to select and validate siRNA target sites.

Wnt signaling and human diseases: what are the therapeutic implications?

Wnt signaling plays an important role in regulating cell proliferation and differentiation. De-regulation of these signaling pathways has been implicated in many human diseases, ranging from cancers to skeletal disorders. Wnt proteins are a large family of secreted factors that bind to the Frizzled receptors and LRP5/6 co-receptors and initiate complex signaling cascades. Over the past two decades, our understanding of Wnt signaling has been significantly improved due to the identification of many key regulators and mediators of these pathways. Given that Wnt signaling is tightly regulated at multiple cellular levels, these pathways themselves offer ample nodal points for targeted therapeutics. Here, we focus on our current understanding of these pathways, the associations of Wnt signaling with human disorders, and the opportunities to target key components of Wnt signaling for rational drug discovery.

Steamed American ginseng berry: ginsenoside analyses and anticancer activities

This study was designed to determine the changes in saponin content in American ginseng berries after treatment by heating and to assess the anticancer effects of the extracts. After steaming treatment (100-120 degrees C for 1 h, and 120 degrees C for 0.5-4 h), the content of seven ginsenosides, Rg1, Re, Rb1, Rc, Rb2, Rb3, and Rd, decreased; the content of five ginsenosides, Rh1, Rg2, 20R-Rg2, Rg3, and Rh2, increased. Rg3, a previously identified anticancer ginsenoside, increased significantly. Two hours of steaming at 120 degrees C increased the content of ginsenoside Rg3 to a greater degree than other tested ginsenosides. When human colorectal cancer cells were treated with 0.5 mg/mL steamed berry extract (120 degrees C 2 h), the antiproliferation effects were 97.8% for HCT-116 and 99.6% for SW-480 cells. At the same treatment concentration, the effects of unsteamed berry extract were 34.1% for HCT-116 and 4.9% for SW-480 cells. After staining with Hoechst 33258, apoptotic cells increased significantly by treatment with steamed berry extract compared with unheated extracts. Induction of apoptosis activity was confirmed by flow cytometry after staining with annexin V/PI. The steaming of American ginseng berries augments ginsenoside Rg3 content and increases the antiproliferative effects on two human colorectal cancer cell lines.

Notoginseng enhances anti-cancer effect of 5-fluorouracil on human colorectal cancer cells

PURPOSE

Panax notoginseng is a commonly used Chinese herb. Although a few studies have found that notoginseng shows anti-tumor effects, the effect of this herb on colorectal cancer cells has not been investigated. 5-Fluorouracil (5-FU) is a chemotherapeutic agent for the treatment of colorectal cancer that interferes with the growth of cancer cells. However, this compound has serious side effects at high doses. In this study, using HCT-116 human colorectal cancer cell line, we investigated the possible synergistic anti-cancer effects between notoginseng flower extract (NGF) and 5-FU on colon cancer cells.

METHODS

The anti-proliferation activity of these modes of treatment was evaluated by MTS cell proliferation assay. Apoptotic effects were analyzed by using Hoechst 33258 staining and Annexin-V/PI staining assays. The anti-proliferation effects of four major single compounds from NGF, ginsenosides Rb1, Rb3, Rc and Rg3 were also analyzed.

RESULTS

Both 5-FU and NGF inhibited proliferation of HCT-116 cells. With increasing doses of 5-FU, the anti-proliferation effect was slowly increased. The combined usage of 5-FU 5 microM and NGF 0.25 mg/ml, significantly increased the anti-proliferation effect (59.4 +/- 3.3%) compared with using the two medicines separately (5-FU 5 microM, 31.1 +/- 0.4%; NGF 0.25 mg/ml, 25.3 +/- 3.6%). Apoptotic analysis showed that at this concentration, 5-FU did not exert an apoptotic effect, while apoptotic cells induced by NGF were observed, suggesting that the anti-proliferation target(s) of NGF may be different from that of 5-FU, which is known to inhibit thymidilate synthase.

CONCLUSIONS

This study demonstrates that NGF can enhance the anti-proliferation effect of 5-FU on HCT-116 human colorectal cancer cells and may decrease the dosage of 5-FU needed for colorectal cancer treatment.

CCN1/Cyr61 is regulated by the canonical Wnt signal and plays an important role in Wnt3A-induced osteoblast differentiation of mesenchymal stem cells

Marrow mesenchymal stem cells are pluripotent progenitors that can differentiate into bone, cartilage, muscle, and fat cells. Wnt signaling has been implicated in regulating osteogenic differentiation of mesenchymal stem cells. Here, we analyzed the gene expression profile of mesenchymal stem cells that were stimulated with Wnt3A. Among the 220 genes whose expression was significantly changed by 2.5-fold, we found that three members of the CCN family, CCN1/Cyr61, CCN2/connective tissue growth factor (CTGF), and CCN5/WISP2, were among the most significantly up-regulated genes. We further investigated the role of CCN1/Cyr61 in Wnt3A-regulated osteogenic differentiation. We confirmed that CCN1/Cyr61 was up-regulated at the early stage of Wnt3A stimulation. Chromatin immunoprecipitation analysis indicates that CCN1/Cyr61 is a direct target of canonical Wnt/beta-catenin signaling. RNA interference-mediated knockdown of CCN1/Cyr61 expression diminished Wnt3A-induced osteogenic differentiation. Furthermore, exogenously expressed CCN1/Cyr61 was shown to effectively promote mesenchymal stem cell migration. These findings suggest that tightly regulated CCN1/Cyr61 expression may play an important role in Wnt3A-induced osteoblast differentiation of mesenchymal stem cells.

[Prediction of curative effect of amblyopia by laser interference fringe visual acuity]

Laser interference fringe visual acuities (IVAs) and E visual acuities (EVAs) of 116 cases 171 amblyopic eyes were examined. All cases were treated by various therapies and the average follow-up was 2.5 years. Before treatment, the IVAs of 86.5% eyes were better than their EVAs and the IVAs of 13.5% eyes were equal to their EVAs. After treatment, the EVAs of all the eyes were raised to their IVA levels (P < 0.0001, r = 0.8218). The results show that the IVA examination can predict the curative effect and monitor the treatment of amblyopia. The relationships between the IVA and the character of visual fixation, the type and degree of amblyopia, elder child and adult amblyopia, etc. were discussed.

Effects of gangliosides GM3 and De-N-acetyl GM3 on epidermal growth factor receptor kinase activity and cell growth

Previously it was reported (Bremer, E.G., Schlessinger, J., and Hakomori, S.-I. (1986) J. Biol. Chem. 261, 2434-2440) that ganglioside GM3 inhibited epidermal growth factor (EGF)-stimulated phosphorylation of the EGF receptor in Triton X-100-treated preparations of human epidermoid carcinoma (A431) cell membranes. In addition, these authors reported that GM3 inhibited the growth of A431 cells. In contrast, a modified ganglioside, de-N-acetyl GM3, enhanced the EGF-dependent tyrosine kinase activity of the EGF receptor. In this work and in subsequent studies (Hanai, N., Dohi, T., Nores, G. A., and Hakomori, S.-I. (1988) J. Biol. Chem. 263, 6296-6301), the tyrosine kinase activity of the receptor from A431 cell membranes was assayed in the presence of Triton X-100. In this report, we confirm that GM3 inhibited and de-N-acetyl GM3 stimulated EGF receptor autophosphorylation in the presence of Triton X-100. However, in the absence of detergents, ganglioside GM3 inhibited EGF-stimulated receptor autophosphorylation, whereas de-N-acetyl GM3 had no effect on EGF-stimulated receptor autophosphorylation. The effects of these gangliosides on receptor autophosphorylation were measured in both A431 cell plasma membranes and in 3T3 cell membranes permeabilized to [32P]ATP by a freeze-thaw procedure, in intact A431 cells permeabilized with alamethicin, and in intact A431 cells grown in the presence of [32P]orthophosphate. Thus, the inhibitory effect of GM3 on receptor autophosphorylation was demonstrated in the presence and in the absence of detergent; the stimulatory effect of de-N-acetyl GM3 was observed only in the presence of detergent. We also demonstrate that ganglioside GM3 inhibited EGF-stimulated growth of transfected murine fibroblasts (3T3) that express the gene for human EGF receptor (Velu, T. J., Beguinot, L., Vass, W. C., Zhang, K., Pastan, I., and Lowy, D. R. (1989) J. Cell. Biochem. 39, 153-166). De-N-acetyl ganglioside GM3 had no effect on the growth of these cells. Growth of control fibroblasts, which lack endogenous EGF receptors (Pruss, R. M., and Herschman, H. R. (1977) Proc. Natl. Acad. Sci. U.S.A. 74, 3918-3921), was not affected by the presence of either ganglioside. Similarly, ganglioside GM3, but not de-N-acetyl ganglioside GM3, inhibited the EGF-dependent incorporation of [3H]thymidine into DNA by transfected fibroblasts. Incorporation of labeled thymidine into DNA of control fibroblasts was not affected by the presence of either ganglioside. These studies indicate that ganglioside GM3, but not its deacetylated analogue, can affect EGF receptor kinase activity in intact membranes.(ABSTRACT TRUNCATED AT 400 WORDS)

[Extramedullary relapse in acute leukemia]

Thirty four cases of isolated extramedullary relapse after complete remission of acute leukemia were reported. The relapse took place in central nervous system (CNS), genito-urinary system, skin, serous cavity, tonsils, lymph nodes, liver, spleen, gastro-intestinal tract, pancreas and ocular fundus. These 34 cases of isolated extramedullary relapse of leukemia was found in 206 cases with complete remission, constituting 16.5% of the total. In order to discover CNS relapse with no symptoms and signs, the author strongly suggest that cerebrospinal fluid examination be carried out periodically. If some symptoms signs in the patient can not explained by infection, congestion or other causes, extramedullary relapse should be considered and further examination and appropriate treatment are needed.

Synthesis and characterization of N-parinaroyl ganglioside GM1: effect of choleragen binding on fluorescence anisotropy in model membranes

N-cis-Parinaroyl ganglioside GM1 and N-trans-parinaroyl ganglioside GM1 were synthesized and characterized by HPLC, TLC, component analysis, absorbance spectroscopy, and proton NMR spectroscopy. Steady-state fluorescence anisotropy of the purified compounds, incorporated into phosphatidylcholine liposomes, was measured in the presence and absence of choleragen (cholera toxin) and choleragenoid (cholera toxin B subunit). In gel-phase liposomes, anisotropy measurements indicated that the motion of the parinaroyl ganglioside was not affected by addition of choleragen or choleragenoid. In fluid-phase liposomes, however, addition of toxin resulted in increased anisotropy (decreased rotational motion) of the fluorescent gangliosides. This decreased motion was not observed with other parinaroyl lipid probes, such as phosphatidylcholine, glucosylceramide, or free fatty acids, indicating that the effect was due to specific ganglioside/toxin interactions. Varying the amount of ganglioside or the amount of toxin suggested that the effect of toxin on probe motion was saturable at approximately 1 choleragen (or choleragenoid) molecule/5 ganglioside molecules. These results are consistent with previous hypotheses regarding the ganglioside/choleragen interaction and indicate that parinaroyl ganglioside probes will be useful in elucidation of the molecular details of this interaction.

Comparison of the effect of scorpion venom (Buthus martensii Kashi) on the rat brain and heart mitochondria

A partially purified fraction SVc and a purified homogeneous polypeptide SVIII were isolated from the scorpion (Buthus martensii Kashi) venom, collected in Shan Dong Province of China. SVc decreased the RCR, ADP/O and Qo2 of the rat brain mitochondria. It also decreased the cytochrome oxidase activity and increased the membrane lipid fluidity of the mitochondria. Effect of scorpion venom on the rat heart mitochondria was somewhat different from that of rat brain mitochondria. SVc also decreased RCR, ADP/O and increased the membrane lipid fluidity of heart mitochondria. However, the Qo2 and cytochrome oxidase activity were increased. SVIII has a similar effect on the rat brain and heart mitochondria, but its concentration used is only 1/10 of the effective concentration of SVc.