Activation of apolipoprotein AI gene expression by protein kinase A and kinase C through transcription factor, Sp1

Our previous finding that insulin induces apolipoprotein AI (apoAI) transcription points to the participation of intracellular signaling. This finding prompted us to ask whether two classical G-protein-coupled signaling pathways requiring activated protein kinase A (PKA) or kinase C (PKC) may also regulate apoAI. Therefore, human hepatoma, Hep G2 cells stably transfected with pAI.474-CAT, a reporter construct spanning -474 to -7 of apoAI DNA fused to chloramphenicol acetyltransferase (CAT) were treated with 10 microm forskolin (FSK) or 50 nm phorbol dibutyrate (PDBu) to activate PKA and PKC, respectively. Results showed that the apoAI promoter activity increased 4-5-fold following 24 h of treatment with either FSK or PDBu. Induction by either agent was blocked with actinomycin D but not the protein synthesis inhibitor, cycloheximide. The PKA inhibitor, PKI 14-22 amide, abrogated induction by FSK, 100 microm 8-bromo-cAMP, or 100 ng/ml cholera toxin, but it had no effect on activation via PKC. Similarly, PDBu induction was attenuated by 2 microm of the PKC inhibitor, GF109203X, but it did not affect FSK activity. Next we used deletional constructs to show that the actions of FSK and PDBu required the insulin-responsive core element (IRCE). This motif matched the consensus binding site for the transcription factor, Sp1. The binding of Sp1 to the IRCE was confirmed by gel-retardation and supershift analysis. Site-directed mutagenesis of the IRCE eliminated Sp1 action and induction by FSK or PDBu. Whereas overexpression of Sp1 enhanced basal and FSK or PDBu induced promoter activity, transfection of an antisense oligomer against Sp1 mRNA attenuated both parameters. In summary, activation of PKA or PKC increases apoAI promoter activity. The activity of both signaling pathways is mediated by the IRCE, a motif that binds the transcription factor, Sp1.

Interleukin-1beta, Src- and non-Src tyrosine kinases, and nitric oxide synthase induction in rat aorta in vitro

We studied the potential roles for endogenous interleukin-1beta (IL-1beta) and for several signaling pathways in the spontaneous induction in vitro of inducible nitric oxide synthase (iNOS) in endothelium-denuded rat aorta rings. Added IL-1beta augmented, whereas the IL-1beta receptor antagonist IL-1ra blocked, spontaneous iNOS induction. Furthermore, increases in IL-1beta mRNA preceded those of iNOS mRNA. Mitogen-activated protein kinase kinase and phosphatidyl inositol 3' kinase inhibition did not block iNOS induction, whereas nuclear factor kappaB inhibition did. The sarcoma virus tyrosine kinase (Src) family-selective inhibitor 4-amino-5(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) blocked the upregulation of IL-1beta mRNA and the subsequent induction of iNOS but not the induction of iNOS stimulated by exogenously added IL-1beta. In contrast, the non-Src inhibitors TP 47/AG 213 and genistein and the tyrosine phosphatase inhibitor vanadate did not affect the spontaneous upregulation of IL-1beta mRNA but blocked both the IL-1beta-mediated and spontaneous induction of iNOS. We conclude that 1) the upregulation of tissue IL-1beta, via a signaling pathway involving a Src family kinase, plays a key role in rat vascular iNOS induction and 2) non-Src tyrosine kinases play roles downstream from IL-1beta for iNOS induction.

Differential induction of nitric oxide synthase in rat gastric and vascular smooth muscle tissue: distinct tissue distribution and distinctive signaling pathways

In rat aorta rings (RA) and in gastric circular muscle (CM) and gastric longitudinal muscle (LM) preparations maintained in vitro, inducible nitric oxide synthase (iNOS) induction was monitored functionally (1 mM L-arginine-induced relaxation), biochemically (appearance of iNOS mRNA), and immunohistochemically. Functional iNOS (L-arginine-mediated relaxation) was induced in RA and CM tissues (but NOT in the LM preparation) over 2 to 5 h. iNOS induction was detected by immunocytochemistry in RA smooth muscle elements and in macrophage-like cells in CM. Functional iNOS induction correlated with iNOS mRNA induction. In the RA and CM, functional iNOS induction was blocked by both actinomycin D and cycloheximide; actinomycin D also blocked the appearance of iNOS mRNA in both tissues. In contrast, cycloheximide blocked CM (but not RA) iNOS mRNA induction. In CM tissue, functional iNOS induction was not affected by genistein, tyrphostin 47/AG213, or vanadate. But, in the RA, both genistein and tyrphostin 47/AG213 blocked the appearance of functional iNOS; neither inhibitor prevented the appearance of RA iNOS mRNA. Vanadate, in the RA tissue, blocked both the appearance of iNOS mRNA and the induction of functional iNOS. In RA tissue, but not in the CM, inhibitors of NF-kappaB activation blocked the appearance of both functional iNOS and iNOS mRNA. We conclude that in different smooth muscle preparations (aorta versus gastric), there can be a differential induction of iNOS mRNA and "functional" iNOS not only in different cellular elements but also in terms of different signaling pathways.

Expression of constitutively activated Gialpha2 in vivo ameliorates streptozotocin-induced diabetes

Streptozotocin treatment in vivo generates a model of insulin-dependent diabetes mellitus via destruction of the pancreatic beta-cells responsible for insulin secretion. Tissue-specific expression of the Q205L constitutively activated mutant form of the G-protein Gialpha2 in vivo ameliorates streptozotocin-induced insulin-dependent diabetes mellitus in transgenic mice. Conditional expression of Q205L Gialpha2 in vivo in liver, skeletal muscle, and adipose tissue markedly rectifies glucose tolerance, fasting glucose levels, and glycogen synthase activation in the mice with insulin-dependent diabetes mellitus, providing a novel therapeutic target for diabetes.

Parallel contractile signal transduction pathways activated by receptors for thrombin and epidermal growth factor-urogastrone in guinea pig gastric smooth muscle: blockade by inhibitors of mitogen-activated protein kinase-kinase and phosphatidyl inositol 3'-kinase

Using a guinea pig gastric longitudinal smooth muscle preparation, we have compared the contractile signaling pathways triggered by the thrombin receptor-activating peptide, TFLLR-NH2 (TF) and by epidermal growth factor-urogastrone (EGF). In addition to inhibitors of tyrosine kinase [tyrphostin 47/AG213, genistein and the src-selective inhibitor CP118,556/PP1], cyclooxygenase (indomethacin, INDO) and diacylglycerol lipase (U57, 908), we also used the signal pathway probe inhibitors of mitogen-activated protein-kinase-kinase (MEK:PD98059), phosphatidylinositol 3'-kinase [PI3K: Wortmannin (WM) and LY294002], protein kinase C [PKC: GF109203X (GF)], and of the EGF-receptor kinase (PD153035). We found that in addition to the inhibition of both TF and EGF-stimulated contractions by the inhibitors of tyrosine kinase, cyclooxygenase and diacylglycerol lipase, the actions of TF and EGF were also attenuated by PD98059, WM/LY294002 and GF. However, PD153035 blocked only EGF-triggered contractions. The contractile actions of both TF and EGF were dependent on extracellular calcium. In contrast, the contractile action of arachidonic acid, via a presumed cyclooxygenase product that mediated the contractions caused by both TF and EGF, was not blocked by any of the signal pathway probe inhibitors. The contractile actions of both TF and EGF were accompanied by increases in tissue phosphotyrosyl proteins and an increase in tissue c-src kinase activity. We conclude that protease-activated receptor no. 1- (thrombin receptor) mediated contractions in the logitudial muscle, like EGF receptor-activated responses, require the influx of extracellular calcium and use parallel signal pathways upstream of the cyclooxygenase step, involving MEK, PI3K, kinase C and possibly cellular src. The TF-induced response did not involve trans-activation of the EGF receptor kinase; but the converse (i.e., trans-activation of protease-activated receptor no. 1 (thrombin receptor) by the EGF receptor kinase) could not be ruled out.

Induction of nitric oxide synthase in rat gastric smooth muscle preparations

The induction in vitro of inducible nitric oxide synthase (iNOS) in intact gastric circular (CM) and longitudinal (LM) smooth muscle preparations was evaluated 1) pharmacologically, by the appearance of 1 mM L-arginine (L-Arg)-induced relaxation in a precontracted tissue; 2) biochemically, according to the appearance of iNOS mRNA using a reverse transcriptase-polymerase chain reaction; and 3) immunohistochemically, using an iNOS-specific antibody. Functionally, iNOS induction affected the contractile properties of the CM but not the LM preparation. The time course of iNOS induction monitored pharmacologically paralleled exactly the appearance of iNOS mRNA. The relaxant response to L-Arg in iNOS-induced CM tissues was blocked by the iNOS inhibitor aminoguanidine and by the guanylyl cyclase inhibitor LY-83583. The addition of oxyhemoglobin to the organ bath also attenuated the relaxant response, but tetrodotoxin had no effect. The transcriptional inhibitor actinomycin D completely blocked iNOS induction as assessed by both pharmacological and biochemical criteria. In iNOS-induced preparations the iNOS immunoreactivity was not detected in the smooth muscle elements but was localized in a layer of macrophage-related cells that were in apposition to the CM smooth muscle elements. We conclude that the spontaneous induction of iNOS in rat gastric tissue can affect the pharmacomechanical reactivity of the CM elements and that this regulation of the CM contractility is due to the induction of iNOS in a set of macrophage-related cells that are closely apposed to the CM elements so that they selectively affect only the contractility of the CM preparation.

Contractile action of ethanol in guinea pig gastric smooth muscle: inhibition by tyrosine kinase inhibitors and comparison with the contractile action of epidermal growth factor-urogastrone

We observed a contractile action of ethanol (20-500 mM) and other alcohols (methanol and propanol, but not butanol) in guinea pig gastric longitudinal (LM) and circular (CM) smooth muscle preparations. The potency order for the alcohols in the LM preparation was: ethanol = propanol > methanol; and in the CM preparation, propanol > ethanol > methanol. Like epidermal growth factor-urogastrone (EGF), the contractile actions of ethanol in the LM and CM preparations required extracellular calcium and were blocked by the tyrosine kinase inhibitors, genistein and tyrphostin-47 (AG213). The tyrosine phosphatase inhibitor, pervanadate, potentiated the contractile action of ethanol in the LM preparation. Ethanol-induced contractions in both preparations were not affected by 4-methyl pyrazole, an inhibitor of alcohol dehydrogenase, and were unaffected by tetrodotoxin, atropine, prazosine or yohimbine. In the LM preparation, like EGF, the contractile action of ethanol was blocked by the cyclooxygenase inhibitor, indomethacin, and the diacylglycerol lipase inhibitor, U57,908; in the CM preparation, contractions caused by ethanol and EGF were still observed in the presence of these two inhibitors. Contractions caused by ethanol and EGF in the LM preparation were not affected by the epoxygenase inhibitor, ketoconazole; the lipoxygenase inhibitor, nordihydroguaiaretic acid; or the phospholipase A2 inhibitor, mepacrine. In contrast, in the LM preparation, EGF-induced contractions were attentuated by the EGF receptor-kinase inhibitor, PD153035; the MAP-kinase-kinase (MEK) inhibitor, PD98059; the kinase C inhibitor, GF109203X; and the phosphatidylinositol 3'-kinase inhibitors, Wortmannin and LY294002; whereas ethanol-induced contractions were unaffected by these inhibitors. Both ethanol and EGF caused small increases in the phosphotyrosyl protein content of the gastric tissue. We conclude that ethanol causes its contractile effects in the distinct gastric LM and CM preparations independent of nerve-released agonists and via a tyrosine kinase inhibitor-sensitive signal pathway that is in many respects similar to, but distinct from the one activated by EGF.

Force measurement on fracture site with external fixation

A force measurement device has been designed to monitor the mechanical properties of fracture site with external fixation. Forces are measured through electric resistance strain gauges mounted on fixation framework and the measurement results are displayed on an LCD screen. The device features a force range of 0-10 kg with linearity and repeatability less than 1% and accuracy less than 0.1 kg.

Tyrosine kinase inhibitor-sensitive contractile action of ethanol in gastric smooth muscle: comparison with the action of epidermal growth factor

We have evaluated the signal transduction pathways whereby, in comparison with epidermal growth factor-urogastrone, ethanol causes a rapid contractile response in guinea pig gastric longitudinal muscle. As for epidermal growth factor (EGF), the ethanol-induced contraction required extracellular calcium, was sensitive to the tyrosine kinase inhibitors genistein and tyrphostin 47 (AG213), and was blocked by both the cyclo-oxygenase inhibitor, indomethacin, and the diacylglycerol lipase inhibitor, U57908. The 50% effective concentration (EC50) for the contractile action of ethanol (approximately 140 mM) was lower than that for propanol and methanol and was not affected by the aldehyde dehydrogenase inhibitor, 4-methyl pyrazole. The actions of ethanol were distinct from those of EGF in that EGF-induced contractions were sensitive to the kinase C inhibitor GF109203X, and the EGF receptor kinase inhibitor PD153035, whereas ethanol-induced contractions were refractory to these inhibitors. Further, EGF-induced contractions were attenuated by the voltage-sensitive calcium channel antagonist, nifedipine, whereas the ethanol-induced contractile response was resistant to nifedipine but blocked by the "receptor-operated" calcium channel antagonist SKF96365. We conclude that ethanol without metabolism via alcohol dehydrogenase causes a contractile response in gastric longitudinal muscle tissue via a tyrosine kinase inhibitor-sensitive signal pathway that is parallel in many respects but yet is distinct from that activated by EGF.

Effect of Panax notoginseng saponins on increased proliferation of cultured aortic smooth muscle cells stimulated by hypercholesterolemic serum

Panax notoginseng saponins (PNS) was extracted from a Chinese herb medicine. After preparation of cultured aortic smooth muscle cell (SMC) from primary aortic explants, the cytotoxicity of hypercholesterolemic serum (HCS) for cultured cells was determined by trypan blue exclusion test, and [3H]thymidine incorporation and cell numbers were counted at the same time. The results showed that HCS (0.5 mg cholesterol.ml-1) increased the incorporation of [3H]thymidine into cultured cells (3722 +/- 440 vs 1655 +/- 288 dpm/microgram cell proteins, P < 0.01), stimulated the proliferation of SMC [(6.5 +/- 1.5) x 10(5) vs (4.3 +/- 1.2) x 10(5) cells/plate, P < 0.01], and that high concentration HCS (final cholesterol concentration 2 mg.ml-1) was cytotoxic to the cultured cells. PNS (100 and 400 micrograms.ml-1) decreased the incorporation of [3H]thymidine into SMC in culture with or without HCS (1292 +/- 260 and 982 +/- 314 or 4111 +/- 886 and 2361 +/- 751 dpm/microgram cell protein), and inhibited the proliferation of the cultured cells [(3.3 +/- 0.7) x 10(5) and (2.9 +/- 0.7) x 10(5) or (4.7 +/- 1.4) x 10(5) and (4.1 +/- 1.2) x 10(5) cells/plate). We conclude that PNS can inhibit the proliferation of aortic SMC stimulated by HCS. These results also suggest that HCS may play an atherogenic role in the arterial wall and that PNS may prevent atherosclerosis and inhibit progression of the atherosclerotic lesions by interfering with the proliferation of arterial SMC.

Preliminary human trial of inactivated golden hamster kidney cell (GHKC) vaccine against haemorrhagic fever with renal syndrome (HFRS)

An inactivated golden hamster kidney cell culture (GHKC) vaccine against haemorrhagic fever with renal syndrome (HFRS) has been developed in recent years. A monovalent GHKC vaccine (lot 88-17) was prepared with L99 strain of the rat-type hantavirus, adapted in suckling mouse brain, cultivated in GHKC, and inactivated with 0.025% formalin, and a preliminary trial of the vaccine was carried out in a small number of human volunteers with the approval of the Ministry of Public Health, PRC, in order to identify safety and antibody response of the vaccine. Three inoculations were made on days 0, 7 and 28 respectively, by the intramuscular route with 1 ml vaccine each time for every volunteer. No obvious side effect was observed in vaccinees within 3 days after each inoculation. All 12 vaccinees (10 received three inoculations, and two received two inoculations of the vaccine) showed positive seroconversion of IgG antibody (by IFAT and ELISA) and neutralizing antibody (by enzyme focus reduction neutralization test, EFRNT), and 10 of them were still seropositive 180 and 360 days after the first inoculation. These results suggest that this vaccine would be safe for human use, and could effectively induce IgG and neutralizing antibody responses.

[Pathological analysis of low rectal malignancy and preservation of anus]

The specimens from 56 low rectal malignancy patients (tumor within 6 cm of anorectal line) who received Miles' operation were pathologically studied. The invasion of sphincter ani had no relation to involvement of the rectal circumference or gross type of the tumor, but was related to the distance between tumor and anorectal line and tumor differentiation. Of 35 patients with tumor 0-3 cm from anorectal line, the sphincter ani was involved in 15 but none in 21 patients with tumor 3.1-6cm from anorectal line (P less than 0.01). There were 1 well-differentiated and 5 poorly-differentiated adenocarcinomas in 15 patients with invasion of sphincter ani, the difference therein was significant (P less than 0.01). The authors suggest that resecting low rectal malignancy but preserving the anus be given to patients with well-differentiated tumors 4-6 cm above the anorectal line.

[Distribution and metabolism of calcium [3H]metronidazolamate in mice]

The blood radioactivity-time curve after iv calcium [3H]metronidazola-mate in mice was to be a diexponential model. It was rapidly distributed in various tissues. The highest radioactivities were found in liver and kidney, followed by lung, blood, heart, spleen, and the lowest in brain and testes. Bile and bone marrow contained only a slight radioactivity. In 7 d the cumulative excretion of radioactivity was 52 +/- 17% of the iv dose in urine and 10.3 +/- 2.4% in feces. The measurement by TLC and liquid scintillation counting of urine taken at 24 h after iv calcium [3H] metronidazolamate to mice revealed that approximately 77% of the total radioactivity in urine was excreted as the drug in unchanged form and 7% as its hydrolysate, metronidazole. Calcium [3H]metronidazolamate remained at a high level in blood on account of its longer T1/2 beta (34 h) and 20% were bound to plasma protein, thus making it available for longterm fractional radiotherapy of tumors.

[Study of Ag-NOR, SCE and micronucleus in peripheral blood lymphocyte of chromate producers]

Ag-NOR, SCE and micronucleus test of peripheral blood lymphocyte obtained from 31 chromate producers had been studied. We found that (1) in the workers who had been exposed over eight years, the frequency of Ag-NOR, Ag-AA and SCE were 6.905 +/- 1.100, 0.380 +/- 0.652 and 8.190 +/- 3.727, but in the control group, 6.512 +/- 1.595, 0.215 +/- 0.529 and 7.171 +/- 2.683, respectively. So there was considerably significant difference between the exposed and the unexposed (P less than 0.01); (2) the frequency of micronuclei was 3.71 +/- 1.419% in the exposed group; however, in the control group it was 0.333 +/- 0.479%. So there was also remarkably significant difference between them (P less than 0.001). The observations lead the authors to conclude that the genetic material of the workers who have been working over eight years may be damaged because of being exposed to chromate.

[Effect of li dan ling in decreasing jaundice and improving liver function in patients with obstructive jaundice]

A total of 89 cases with extrahepatic jaundice were studied clinically. All patients were divided into two groups at random: control group and Li Dan Ling treatment group. It was found that: (1) liver functions in the patients with obstructive jaundice were injured severely; bilirubin, R15ICG, m-GOT, and gamma-GT were increased significantly; (2) in patients with incomplete biliary obstruction or after the relief of obstruction, liver functions could be improved gradually. They were improved more quickly in patients of the Li Dan Ling treatment group; (3) for the patients suffering from complete biliary tract obstruction, until the obstruction was relieved liver function could not be improved. After the herbal medicine, all the indicators would be further worsened before the relief of the obstruction, and the value of "b" would be positive. The increase in m-GOT and gamma-GT was higher than in the control group, indicating the liver functions were further injured. Therefore, the herbal cholegogue was not suitable for the patients before the obstruction was relieved. The further investigations showed that excretion of bilirubin from the bile could be accelerated by Li Dan Ling, and after herbal administration, the cholesterol level in bile was lowered significantly; the liver blood flow in normal and jaundiced rats would be increased 30 to 90 min. after administering the herbs.

Acupuncture therapy in acute abdomen

Acupuncture as a therapeutic measure for abdominal pain was early recorded in Huangdi Neijing ("Yellow Emperor's Canon of Medicine"). Fruitful experiences have been accumulated in the practice of the long historical years. Nowadays acupuncture therapy has become one of the main therapeutic methods in surgical acute abdomen and is widely used clinically.