Okadaic acid is a potent tumor promoter and an inhibitor of serine/threonine-specific protein phosphatases. We studied the effect of okadaic acid in human T cell activation and phosphorylation of internal substrates. Okadaic acid at up to 4 nM enhanced phorbol myristate acetate (PMA)-induced proliferation and CD25 (IL-2 receptor, p55) expression, although it showed no activation by itself. Okadaic acid induced hyperphosphorylation of a 60 kDa protein in T cells as well as non-T cells, as reported in fibroblasts and keratinocytes. Preincubation with 4 nM okadaic acid enhanced PMA induced phosphorylation of the 80 kDa protein, an internal substrate of protein kinase C in T cells. These results suggest that okadaic acid inhibited dephosphorylation of protein kinase C specific substrates, and as a result, enhanced T cell activation mediated by protein kinase C pathway.

Ethers, Cyclic↗

PubMedDate not supplied

Local administration of estrogen inhibits transplant arteriosclerosis in rat aorta accelerated by topical exposure to IGF-I.

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Animals↗

PubMedDate not supplied

Serum and urine inorganic fluoride levels following prolonged low-dose sevoflurane anesthesia combined with epidural block.

STUDY OBJECTIVES: To determine whether serum and urine inorganic fluoride levels with prolonged (more than 7 hours) low-dose (0.8 to 2.0 vol %) sevoflurane anesthesia plus epidural anesthesia were increased as compared with isoflurane anesthesia plus epidural anesthesia. To measure the urine tubular enzymes N-acetyl-beta-glucosaminidase (NAG), alpha 1-microglobulin (alpha 1-M), and beta 2-microglobulin (beta 2-M) for renal tubular injury in both groups. DESIGN: Randomized, prospective study. SETTING: University hospital. PATIENTS: 15 ASA physical status I and II adults (7 males, 8 females) who were scheduled for prolonged laparotomy (lasting 9.5 to 10.2 hours) with general anesthesia. MEASUREMENTS AND MAIN RESULTS: Epidural anesthesia was administered before induction of general anesthesia. General anesthesia was induced with thiamylal administered intravenously (IV), and the trachea was intubated following administration of vecuronium IV. It was maintained with either sevoflurane or isoflurane in nitrous oxide and oxygen. Standard monitoring was used in all patients. Serum and urine inorganic fluoride and urine tubular enzymes were measured periodically. Serum inorganic fluoride was 54 mumol/L at 4.3 minimum alveolar concentration (MAC) hours of sevoflurane; the peak level for isoflurane was 8 mumol/L at the same MAC hours. Sevoflurane also increased urine inorganic fluoride excretion to 96 mumol/hr 8 hours. NAG excretion started to increase after inhalation of either sevoflurane or isoflurane. alpha 1-M and beta 2-M excretion increased markedly postoperatively. Even though fluoride levels and tubular enzymes were high, there was no evidence of postoperative renal dysfunction. CONCLUSIONS: There was no increase in urinary enzymes, which are indicators of tubular injury, specific to sevoflurane. There was no postoperative renal dysfunction, as indicated by unchanged serum creatinine and blood urea nitrogen levels.

Acetylglucosaminidase↗

PubMedDate not supplied

Gene delivery systems using the Sendai virus.

Fusogenic liposome (FL) is a delivery system that can transfer encapsulated materials into living cells directly through membrane fusion. FL is a promising approach for gene therapy because it can deliver various genetic materials much more efficiently than other non-viral vectors without damaging the cell. FL-mediated gene transfer consists of two independent membrane fusion phenomena; generation of a FL by fusing a Sendai virus (SV) particle with a simple liposome encapsulating DNA, and successive fusion of the FL with cell membrane. The former requires viral F protein but no other special molecule on the liposomal membrane, whereas the latter may require the receptor (sialic acid) and unidentified assistant molecule(s) on the cell membrane. Further analysis suggests that these assistant molecule(s), not the receptor, may control the fusion and govern the cell specificity of FL-mediated delivery. This review has described a detailed analysis of these fusion phenomena and discussed possible applications of FL-mediated gene delivery to human gene therapy.

Genetic Therapy↗

PubMedDate not supplied

Effects of rat hepatocytes on macromolecular permeability of bovine aortic endothelial cell monolayer.

The aim of this study was to examine whether the hyperpermeable structure of the liver endothelium in vivo is related to the interactions of hepatocytes in a culture system. The permeation of macromolecular FITC-labeled dextran (molecular weight 70,000) through a monolayer of bovine aortic endothelial cells (BAEC), cocultured with rat parenchymal hepatocytes (P-hep), was increased. When the BAEC were cocultured with nonparenchymal hepatocytes (N-hep), the permeability of the BAEC monolayer was not increased. However, when the BAEC were cocultured with a mixture of P-hep and N-hep (PN-hep), the BAEC monolayer was more permeable than when BAEC were cocultured with P-hep alone. The conditioned medium of P-hep did not alter the BAEC monolayer permeability, nor did the extracellular matrix of P-hep alter BAEC permeability. When the BAEC were cocultured with PN-hep, the F-actin content was not altered. These findings suggest that the interaction between hepatocytes and endothelial cells exerts an important effect on the hyperpermeable structure of the liver vessels in vivo.

Actins↗

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Preparation of influenza virosome vaccine with muramyldipeptide derivative B30-MDP.

An influenza virosome vaccine, consisting of influenza hemagglutinin-neuraminidase antigens (HANA), the muramyldipeptide derivative 6-O-(2-tetra-decylhexadecanoyl)-N-acetyl-muramyl-L-alanyl-D-isoglu tamine (B30-MDP) and cholesterol, was prepared by the detergent removal method using a flow-through dialyzer, Liposomat. The shape of the influenza virosome vaccine mimicked that of the influenza virus, namely, B30-MDP/cholesterol vesicle covered with HANA spikes. THe particle size and size distribution of prepared virosomes were evaluated by quasi-elastic laser light scattering and gel permeation chromatography. The state of incorporation of HANA spikes at the membrane surface of virosome was confirmed by electron microscopy. The results indicated that virosome formation was influenced by initial B30-MDP concentration in the mixed micellar solution prior to dialysis. It is apparent that the initial concentration of B30-MDP, relative to the mixed-micelle-to-virosome transition, is an important factor for virosome preparation. Accordingly, the transition was evaluated and clarified by the changes in membrane fluidity and particle size during the dialysis process. The results indicated that it is important to adjust the initial B30-MDP concentration in the mixed micellar solution before dialysis so that the concentration for the mixed-micelle-to-vesicle transition coincides with that for mixed-micelle-to-rosette-transition appropriate for virosome formation.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMedDate not supplied

Human lymphoblastoid and fibroblast interferon in the treatment of chronic hepatitis B.

Twenty-six patients, positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus (HBV)-deoxyribonucleic acid (DNA), and DNA polymerase activity, were treated with human lymphoblastoid interferon (IFN-alpha) or human fibroblast interferon (IFN-beta) after enoxolone glycoside (glycyrrhizinic acid), given for four weeks and then withdrawn. The interferons were given continuously for four weeks. Four months after the treatment, six of 12 patients treated with IFN-alpha were both HBeAg-negative and HBV-DNA-negative while three of 14 patients treated with IFN-beta were HBV-DNA-negative and one was HBeAg-negative. None of the ten untreated control patients became negative for either HBeAg or HBV-DNA. All patients studied remained HBsAg-positive. Both interferons were generally well tolerated. A persistent low-grade fever was reported by more patients in the IFN-beta group and hair and weight loss were more common in the IFN-alpha group. The results indicate that the combination of enoxolone glycoside withdrawal and IFN-alpha treatment reduces HBV replication more effectively than does interferon alone.

Adolescent↗

PubMedDate not supplied

Enhancing effect of nonionic surfactant on the inactivation of lipopolysaccharide by steam-heat treatment II.

n-alkylpolyoxyethylene surfactants (CnH2n+1O(CH2CH2O)mH; CnEm) showed a strong enhancing effect on the inactivation of lipopolysaccharide (LPS) by heat treatment over a wide range of temperatures. The effect of CnE8 (n = 10-16) was observed above the critical micelle concentration (CMC) and above the cloud point, and was influenced by the length of the alkyl chains. The efficacy of the surfactants was in the order C10E8 < C12E8, C16E8 < C14E8. However, the hydrophilic moiety seemed to have no influence. An 80-95% solution of n-butanol showed a similar effect, indicating that LPS was more effectively inactivated in the oily phase of the surfactants than in water. The effect of surfactant on the hydrodynamic diameter of LPS was the same before and after steam-heat treatment for 20 minutes at 121 degrees C. Each surfactant disaggregated LPS without alteration of the activity of LPS before the heat treatment. We consider that the surfactants interact with LPS in the region of lipid A in a manner that favors loss of the activities of LPS during heating.

Chemical Phenomena↗

PubMedDate not supplied

Drug resistance and P-glycoprotein expression in endothelial cells of newly formed capillaries induced by tumors.

The inhibitory effects of vincristine (VCR) with or without verapamil (VER) on angiogenesis in mouse subcutaneous fascia induced by mouse sarcoma 180 cells were assessed using the dorsal air sac method. VCR combined with VER had inhibitory effects on tumor-induced angiogenesis, but VCR alone did not inhibit capillarization. The chemosensitivity of human umbilical vein endothelial cells (HUVEC) and tumor-derived endothelial cells from rat KMT-17 fibrosarcoma (TEC) was examined using the microculture tetrazolium assay. VCR and taxol had strong anti-proliferative activity against HUVEC, but only weakly inhibited the proliferation of TEC. In combination with VER, VCR and Taxol inhibited the proliferation of TEC. Cisplatin, mitomycin C, and 5-fluorouracil had weakly anti-proliferative activity against both HUVEC and TEC. Expression of P-glycoprotein (P-gp) was found in TEC, but not in HUVEC using western blot analysis. These findings indicate that drug resistance and P-gp expression appeared on newly formed capillaries induced by rodents tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗