Chronic ethanol inhibits inositol metabolism in specific brain regions

Many neurotransmitters and hormones in the nervous system transmit signals through receptors coupled to the poly-phosphoinositide (PI) signaling pathway. In this study, an in vivo protocol with [3H]inositol was used to examine the effect of chronic ethanol administration on inositol metabolism and poly-PI turnover in the cerebral cortex, hippocampus, and cerebellum of mouse brain. C57BL/6 mice were given a nutritionally complete liquid diet containing either ethanol (5%, w/v) or isocaloric sucrose for 2 months. Mice were injected intracerebrally with [3H]inositol; after 16 or 24 hr, they were injected intraperitoneally with lithium (8 mEq/kg body weight) to inhibit the inositol monophosphatase (IP1) activity. All mice were decapitated 4 hr after lithium injection. Labeled inositol phospholipids accounted for 16 to 23% of total labeled inositol in different regions of control mouse brain, and the percentages in the hippocampus were consistently higher than the cerebral cortex and cerebellum. In control mice, the percentages of labeled IP1 after a 4-hr lithium treatment were 11.5%, 9.9%, and 3.7% for cerebral cortex, hippocampus, and cerebellum, respectively. Chronic ethanol feeding resulted in a significant (p < 0.05) decrease in the percent of labeled IP1 and inositol phospholipids, and this effect was observed in the cerebral cortex and, to a lesser extent, hippocampus but not cerebellum. When ratios of labeled IP1 were expressed against labeled inositol phospholipids as an index of the poly-PI turnover activity, significant decreases in IP/lipid ratios were observed in the cerebral cortex, but not the hippocampus or cerebellum. Although mice killed 24 + 4 hr after the last ethanol feeding would have experienced an 8-hr period of ethanol withdrawal, compared with the 16 + 4-hr group, no differences in IP/lipid ratios were observed between the two time groups. These results illustrate regional differences in the effect of chronic ethanol on inositol metabolism in the brain, but no difference in poly-PI turnover in brain due to ethanol withdrawal.

Crystal structure of desheptapeptide(B24-B30)insulin at 1.6 A resolution: implications for receptor binding

The crystal structure of desheptapeptide (B24-B30) insulin (DHPI), a virtually inactive analog of insulin, was determined at 1.6 A resolution. In the refined structure model, DHPI retains three alpha-helices (A1-A8, A12-A18, and B9-B19) as its structural framework, while great conformational changes occur in the N and C termini of B-chain. The beta-turn, which lies in B20-B30 in insulin and insulin analogs with high potency, no longer exists in DHPI. Relative motion is observed among the three alpha-helices, each as a rigid functional group. In contrast, a region covering B5-B6 and A6-A11 exhibits a relatively stable conformation. We interpret our results as identifying: (i) the importance of beta-turn in determining the receptor-binding potency of insulin and (ii) a leading role of PheB24 in maintaining the beta-turn structure.

Effects of Ro 31-8220 on lipopolysaccharides-induced hepatotoxicity and release of tumor necrosis factor from rat Kupffer cells

AIM

To investigate protein kinase C (PKC) functions on lipopolysaccharide (LPS)-induced hepatotoxicity, a new potent PKC inhibitor Ro 31-8220 (Ro) was used to detect its effect on LPS-induced hepatotoxicity in rat hepatocytes and tumor necrosis factor (TNF) release from rat Kupffer cells (KC).

METHODS

Hepatocytes (containing KC) were incubated with LPS (10 mg.L-1) and Ro (0.1-10 mumol.L-1) for 24 h, alanine aminotransferase (AlaA) leakage in the culture as indication of hepatotoxicity. The TNF activity in the supernatant of rat KC culture with LPS in the presence of Ro (0.1-10 mumol.L-1) was monitored by the L929 target cell lytic assay.

RESULTS

Ro (0.1-10 mumol.L-1) reduced AlaA leakage in the hepatocyte culture. Ro inhibited dose-dependently the LPS-induced TNF production from rat KC.

CONCLUSION

PKC inhibitor Ro protects the hepatocytes from LPS-induced cytotoxicity and inhibits the LPS-induced TNF production from rat KC.

Hormone receptors in vestibular schwannomas

The possibility that steroid hormones play a role in vestibular schwannoma proliferation has been suggested by a number of investigators. There is conflicting information about the presence of steroid hormone receptors in these tumors. The aim of this study was to examine the expression of androgen, progesterone, glucocorticoid and estrogen receptor messenger ribonucleic acid levels (mRNA) in twenty-one vestibular schwannomas by either Northern blot analysis or the polymerase chain reaction (PCR). Glucocorticoid receptor mRNA was expressed in all twenty-one tumors examined. Only two male specimens were positive for androgen receptor mRNA expression by PCR-Southern blot analysis. Thirty-three percent of the schwannomas (7/21) showed a strong band for progesterone receptor mRNA by PCR-Southern blot analysis; there were an equal number of males and females in this group. Estrogen receptor mRNA levels were undetectable in all tumors examined by PCR-Southern blot analysis. These studies suggest that the pattern of steroid receptor expression is different in schwannomas than in meningiomas. Individual vestibular schwannomas need to be examined for their steroid receptor mRNA expression mRNA expression to know whether they will be responsive.

Crystal structure of R-phycoerythrin from Polysiphonia urceolata at 2.8 A resolution

The structure of R-phycoerythrin (R-PE) from Polysiphonia urceolata was determined at 2.8 A resolution. The crystals belong to space group R3 with unit cell dimensions of a = b = 189.8 A, c = 60.1 A. The subunit composition of R-PE is (alpha 2 beta 2)3 gamma. The three-dimensional structure of R-PE was solved by the multiple isomorphous replacement method. After several cycles of model building and refinement, the crystallographic R-factor of the final model is 18.0% with data from 10.0 to 2.8 A resolution. The four phycoerythrobilin chromophores alpha 84, alpha 140a, beta 84 and beta 155 in an (alpha beta) unit are each covalently bound to a cysteine residue through ring A. The phycourobilin chromophore is bound to cysteine beta 50 by ring A and bound to cysteine beta 61 by ring D. The ring A and ring D of phycourobilin deviate from the conjugate plane formed by ring B and ring C and the four rings form a boat-shaped structure. R-PE contains a 34 kDa gamma subunit that is assumed to lie in the central channel of the molecular disc (alpha 2 beta 2)3. The energy transfer and relationship between cysteine residues and chromophores are discussed.

Chronic ethanol on mRNA levels of IP3R1, IP3 3-kinase and mGluR1 in mouse Purkinje neurons

Chronic ethanol exposure is known to alter the polyphosphoinositide (poly-PI) signaling pathway, although the exact sight of regulation is not well understood. In this study, C57B1/6J mice were given a control or an ethanol (6 g kg-1 body wt) liquid diet by gastric intubation daily for 4 weeks. Examination of levels of mRNA for type 1 inositol 1,4,5-trisphosphate receptor (IP3R1), inositol 1,4,5-trisphosphate 3-kinase (IP3K) and metabotropic glutamate receptor 1 (mGluR1) in cerebellar Purkinje neurons by in situ hybridization revealed significant decreases in cellular levels of mRNA encoding both IP3R1 and mGluR1 in the ethanol-treated group compared with controls, but levels of IP3K mRNA were not altered. These results suggest that chronic ethanol consumption selectively alters cellular mRNA in the poly-PI signaling pathway. The decrease in mRNA levels of mGluR1 and IP3R1 may be an important underlying mechanism towards explaining the alcohol-induced degenerative changes in the cerebellar Purkinje neurons.

Induction of gene expression in Escherichia coli after pilus-mediated adherence

The induction of cascades of virulence factors after contact between bacteria and host cells was investigated. P-pili mediate the binding of uropathogenic Escherichia coli to its host cell receptor. After P-pili binding there was transcriptional activation of a sensor-regulator protein that is essential for the bacterial iron-starvation response. An insertion mutation of the sensor-regulator gene eliminated the ability of uropathogenic E. coli to produce siderophores and their iron-regulated membrane receptors, thereby abolishing their ability to grow in urine. These results suggest that P-pilus-mediated attachment may be an important part of the sensor-regulatory process involved in uropathogenic E. coli urinary tract infection.

Effect of matrine on lipopolysaccharides/D-galactosamine-induced hepatitis and tumor necrosis factor release from macrophages in vitro

AIM

To study the effects of matrine (Mat) on lipopolysaccharides (LPS)-induced fatal hepatitis in D-galactosamine (D-GalN)-sensitized mice and tumor necrosis factor (TNF) release from peritoneal macrophages (PMO).

METHODS

Mice were pretreated with Mat (10, 50 mg.kg-1, i.p., bid x 3 d), and then injected i.p. LPS + D-GalN. Liver injury was assessed by quantifying plasma activity of alanine aminotransferase (ALT) and histopathological examination. The TNF activities in the supernatants of mouse PMO stimulated with LPS in the presence of Mat (32.5-500 mg.L-1) were monitored by the L929 target cells lytic assay.

RESULTS

Mat pretreatment markedly diminished hepatic injury induced by LPS in combination with D-GalN. Mat inhibited LPS-induced TNF release from mouse PMO in vitro in a concentration-dependent manner.

CONCLUSION

Mat protected the D-GalN-treated mice from the development of fatal hepatitis induced by LPS, and inhibited the LPS-induced TNF release from mouse PMO.

Brain neutral lipids and phospholipids are modified by long-term feeding of beef tallow vs. corn oil diets

Previous studies examining the response of brain lipids to dietary fat modification have not quantified neutral lipids such as diacylglycerols (DG) and triacylglycerols (TG). In this study we measured the concentrations of neutral lipids and phospholipids, and their fatty acid profiles, in the cerebra of rats fed defined diets containing either beef tallow (BT) or corn oil (CO) at 12% or 37% of energy. The diets were fed to rat pups beginning at 18 d of age and continued for 31 wk. The proportion of brain linoleic acid [18:2(n-6)] in TG from CO-fed rats was two- to fourfold greater than in BT-fed rats. Although 18:2(n-6) levels were higher in serum and brain TG of rats fed CO, differences in other TG fatty acid concentrations in serum were not reflected in the brain. Rats fed CO diets had higher concentrations of 18:2(n-6) in brain phospholipids as well as neutral lipids compared with rats fed BT diets, and the differences were greater in rats fed 37% rather than 12% of energy as fat. Differences in other polyunsaturated fatty acids associated with dietary fat composition were also found among the brain phospholipids. Most notably, the concentration of docosapentaenoic acid [22:5(n-6)] in brain phospholipids was highest in rats fed diets containing the lowest concentrations of alpha-linolenic acid [18:3(n-3)]. A concentration of 0.1 mg 18:3(n-3)/g diet appeared to be adequate to prevent elevation of 22:5(n-6) in brain phospholipids. These results demonstrate that consumption of a low fat diet (12% of energy) primarily comprised of saturated fats may potentiate an 18:3(n-3) deficiency in brain of rats.

Structural requirements of heparin binding to Chlamydia trachomatis

Heparin is a functional and structural analog of the Chlamydia trachomatis heparan sulfate-like attachment ligand that mediates infectivity by bridging chlamydiae to eukaryotic cells. The binding of heparin to the Chlamydia organism's surface was characterized by a direct binding assay. Although for two C. trachomatis biovars the binding by heparin was saturable, trachoma biovar organisms bound twice the amount of heparin than lymphogranuloma venereum biovar organisms. To prove the structural nature of the heparan sulfate-like ligand interactions, a range of heparin-derived oligosaccharides and sulfation-modified species of heparin were compared for their ability to compete with [3H]heparin for binding to chlamydial organisms and for inhibition of chlamydial attachment and infection of eukaryotic host cells. The assays revealed that a decasaccharide was the minimal chain length required to effectively bind C. trachomatis organisms, compete with the host cell receptor and rescue infectivity. In addition, a moderately sulfated adhesin analog, N-desulfated, N-acetylated heparin, was able to compete with chlamydial organisms for host cell receptors, whereas this derivative could not compete with [3H]heparin for binding to chlamydial organisms. These results indicate that the specificity of the eukaryotic cell receptor and the chlamydial surface acceptor differ in their fine-structure requirements of ligand binding, and that the size and sulfation density of the heparan sulfate-like ligand each contribute to its ability to bind and bridge chlamydiae to eukaryotic cells.

Effects of matrine on mouse splenocyte proliferation and release of interleukin-1 and -6 from peritoneal macrophages in vitro

AIM

To investigate the mechanisms of anti-inflammatory effect of matrine (Mat), its effects on mouse splenocyte proliferation, and release of interleukin-1 (IL-1) and interleukin-6 (IL-6) from mouse peritoneal macrophages.

METHODS

Splenocyte proliferation was assayed by [3H] TdR incorporation. IL-1 and IL-6 activities were measured by thymocyte proliferation assay and B9 cell proliferation MTT colorimetric method, respectively.

RESULTS

Mat (125-500 mg.L-1) obviously inhibited concanavalin A (Con A, 5 mg.L-1)- and lipopolysaccarides (LPS, 10 mg.L-1)-induced splenocyte proliferation and LPS-induced release of IL-1 and IL-6 from mouse peritoneal macrophages.

CONCLUSION

Mat inhibited splenocyte proliferation and release of IL-1 and IL-6 in vitro.

Inhibitory effect of quercetin on tumor necrosis factor and interleukin-1 beta pro-osteoclastic activities

AIM

To study the effects of quercetin on tumor necrosis factor (TNF) and interleukin-1 beta (IL-1 beta) pro-osteoclastic activities.

METHODS

[3H] TdR uptake by osteoblasts was used to measure cell proliferation, microspectrophotometer for cellular AIP activity using p-nitrophenyl phosphate as enzyme substrate, and radioimmunoassay for prostaglandin E2.

RESULTS

Quercetin 5-40 mumol.L-1 reduced the inhibition of cell proliferation and AIP activity induced by TNF or IL-1 beta in a concentration-dependent manner. PGE2 production stimulated by either cytokines was also reduced by quercetin at 20 and 40 mumol.L-1.

CONCLUSION

quercetin exerted a marked inhibitory effect on TNF and IL-1 activities, related to their pro-osteoclastic function.

[Inhibitory effects of protein kinase C inhibitors on tumor necrosis factor induced bovine pulmonary artery endothelial cell injuries]

The effects of protein kinase C(PKC) inhibitors 1-(5-isoquino-linylsulfonyl)-2-methylpeperazine (H-7) and quercetin on tumor necrosis factor (TNF) were studied in cultured bovine pulmonary artery endothelial cells (BPAEC) in vitro. Incubation of BPAEC with TNF caused a significant increase in percent lactate dehydrogenase (LDH) release, stimulation of EC-dependent neutrophils (PMN) adhesion to BPAEC and inhibition of BPAEC DNA synthesis and proliferation. All these were restored by both H-7 and quercetin. The IC50 of H-7 and quercetin was 9.7 and 10.8 mumol.L-1 for the inhibition of LDH% release; 19.5 and 16.7 mumol.L-1 for the inhibition of TNF-induced PMN-EC adhesion; 7.0 and 6.1 mumol.L-1 for TNF-induced inhibition of DNA synthesis and 8.7 and 11.36 mumol.L-1 for proliferation. These results suggest that PKC inhibitors H-7 and quercetin protect BPAEC from TNF induced injuries and PKC play an important role in EC activation by TNF.

[Effect of matrine on mouse hepatitis and tumor necrosis factor production induced by Propionibacterium acnes/lipopolysaccharides]

The effect of matrine (Mat) on lipopolysaccharides (LPS)-induced fatal hepatitis and tumor necrosis factor (TNF) production in Propionibacterium acnes (PA)-primed mice were studied. Mice were injected i.p. LPS (10 micrograms/mouse) 7 d after i.p. PA (0.5 ml/mouse) to induce fatal hepatitis. After i.p. LPS, serum TNF activity rose to 1657 +/- 406 kU.L-1 at 1.5 h and ALT activity increased up to 1,496 +/- 890 U.L-1 at 5 h. Six of 8 mice died within 5 h and the massive hemorrhagic necrosis of the liver was observed in all mice. Administration of Mat (10, 50 mg.kg-1, i.p., bid x 3 d) before the LPS injection markedly reduced the elevation of serum TNF and ALT activity in a dose-dependent manner, and diminished the mortality induced by LPS. Liver congestion and necrosis induced by LPS in PA-primed mice were ameliorated markedly by Mat pretreatment. Mat (62.5-250 mg.L-1) inhibited LPS-induced TNF release from PA-primed mouse peritoneal macrophage in vitro in a concentration-dependent manner. These results seggest that Mat protected PA-primed mice from the development of fatal hepatitis induced by LPS due to inhibition of TNF production.

In utero hypoxic ischemia decreases the cholinergic agonist-stimulated poly-phosphoinositide turnover in the developing rat brain

Perinatal hypoxic-ischemic (HI) insult is known to cause cellular and molecular disturbances leading to functional and behavioral abnormalities during brain development. In this study, we examined the effects of an in utero HI insult on poly-phosphoinositide turnover in vivo in the cerebrum and cerebellum as well as cholinergic-stimulated turnover in cortical slices from developing rat brain. In utero HI treatment was carried out by clamping the uterine blood vessels of near-term fetuses for 5, 10 and 15 min followed by resuscitation of the newborn pups. The in vivo protocol for examining poly-PI signaling activity in 2 week-old pup brain involved intracerebral injection of [3H]inositol for 16 hr and subsequent intraperitoneal injection with lithium (8 meq/kg) for 4 hr prior to decapitation. In the control pups, lithium elicited a 2.6 fold increase in labeled inositol phosphate (IP) in the cerebrum as compared to a 1.3 fold increase in the cerebellum. In utero HI insult (5 to 15 min) resulted in a small increase in labeled IP in the cerebrum but not in the cerebellum. Carbachol stimulation of poly-PI turnover was examined in brain slices prelabeled with [3H]inositol in vivo. Incubation of the prelabeled slices with carbachol in the presence of LiCl (10 mM) resulted in a time-, dose- and age-dependent increase in labeled IP. Brain slices from 2 week-old pups that experienced in utero HI-treatment for 10 and 15 min (but not 5 min) showed a significant decrease in carbachol-stimulation of labeled IP as compared with control pups. These results indicate the effects of in utero HI on the choninergic-stimulated poly-PI signaling pathway and its implication on related functional deficits in the developing brain.

Regulation of FFA by the acyltransferase pathway in focal cerebral ischemia-reperfusion

Cerebral insult is associated with a rapid increase in free fatty acids (FFA) and arachidonic acid release has been linked to the increase in eicosanoid biosynthesis. In transient focal cerebral ischemia induced by middle cerebral artery (MCA) occlusion, there is an inverse relationship between the increase in FFA and the decrease in ATP, both during the ischemia period and at later time periods after reperfusion. In this study, the focal cerebral ischemia model was used to examine incorporation of [14C]arachidonic acid into the glycerolipids in rat MCA cortex at different reperfusion times after a 60 min ischemia. The label was injected intracerebrally into left and right MCA cortex 1 hr prior to decapitation. Labeled arachidonic acid was incorporated into phosphatidylcholine, phosphatidylethanolamine and neutral glycerides. With increasing time (4-16 hr) after a 60 min ischemia, an inhibition of labeled arachidonate uptake could be found in the right ischemic MCA cortex, whereas the distribution of radioactivity among the major phospholipids was not altered. When compared to labeled PC, there was a 3-4 fold increase in incorporation of label into phosphatidic acid and triacylglycerols (TG) in the right MCA cortex, suggesting of an increase in de novo biosynthesis of TG. In an in vitro assay system, synaptosomal membranes isolated from MCA cortex 8 and 16 hr after a 60 min ischemia showed a significant decrease in arachidonoyl transfer to lysophospholipids, due mainly to a decrease in lysophospholipid:acylCoA acyltransferase activity. Assay of phospholipase A2 activity with both syaptosomes and cytosol, however, did not show differences between left and right MCA cortex or with time after reperfusion. These results suggest that besides ATP availability, the decrease in acyltransferase activity may also contribute to the increase in FFA in cerebral ischemia-reperfusion.

Protein kinase C inhibitor H-7 blocks effects of tumor necrosis factor on bone cells

AIM

To study the effects of tumor necrosis factor (TNF) on the neonatal mouse osteoblast-enriched calvarial cells and effects of protein kinase C (PK C) inhibitor, 1-(5-isoquinolinesulfonyl)-2 -methylpiperazine (H-7) on the TNF actions.

METHODS

[3H]TdR uptake by the osteoblasts was used to measure cell proliferation. Cellular alkaline phosphatase (AIP) and tartrate resistant acid phosphatase (trAcP) activities were determined spectrophotometrically.

RESULTS

TNF (1-100 kU . L-1) inhibited both proliferation and expression of AIP activity, but stimulated trAcP activity. These TNF-induced actions were blocked by simultaneous addition of H-7 (5-20 mumol . L-1).

CONCLUSION

TNF has potent effects on the osteoblasts, and the blockade of TNF actions by H-7 suggests that TNF exert its effects through PK C.

Inositol trisphosphate, polyphosphoinositide turnover, and high-energy metabolites in focal cerebral ischemia and reperfusion

BACKGROUND AND PURPOSE

Although the signaling pathway involving polyphosphoinositide (poly-PI) hydrolysis and release of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] is an important mechanism for regulation of neuronal calcium homeostasis, the effect of cerebral ischemia-reperfusion on this calcium signaling pathway is not well understood. Because activity of this pathway is dependent on availability of ATP, this study is aimed at examining the poly-PI signaling pathway and high-energy metabolites in a rat stroke model.

METHODS

Focal cerebral ischemia in rats was induced by temporary occlusion of the right middle cerebral artery and both common carotid arteries. Levels of Ins(1,4,5)P3 were determined by use of the radioreceptor binding assay. Poly-PI turnover in rat cortex was assessed with an in vivo protocol involving intracerebral injection of [3H] inositol and systemic administration of lithium. High-energy metabolites (ATP, ADP, and AMP) were analyzed by high-performance liquid chromatography.

RESULTS

Ischemia induced an increase in poly-PI turnover in the right middle cerebral artery cortex, but reperfusion led to a decline in this signaling activity. However, Ins(1,4,5)P3 levels decreased during ischemia, and these levels were not restored if ischemic insults were longer than 30 minutes. ATP levels decreased to 26% of control during ischemia and recovered to 80% of control during the initial 4 hours of reperfusion; these changes were followed by a second phase of decline.

CONCLUSIONS

Results show an important relationship between ischemia-induced depletion of high-energy metabolites and poly-PI signaling activity. However, the uncoupling between Ins(1,4,5)P3 and ATP during reperfusion after severe ischemia suggests that metabolism of Ins(1,4,5)P3 is more stringently regulated than ATP.

In situ hybridization of mRNA expression for IP3 receptor and IP3-3-kinase in rat brain after transient focal cerebral ischemia

Loss of intracellular calcium homeostasis has been regarded an important factor underlying neuron cell death after cerebral ischemic insult. In the brain, a major mechanism for regulation of intracellular calcium is through the signal transduction pathway involving hydrolysis of poly-phosphoinositides and release of the second messenger, inositol 1,4,5-trisphosphate (IP3). IP3 mobilizes calcium by interacting with an intracellular receptor. Upon its release after agonist stimulation, this second messenger is catabolized by a 3-kinase and a 5-phosphatase. In this study, in situ hybridization was carried out to examine the mRNA expression of IP3, receptor (IP3R) and IP3 3-kinase (IP3K) in rat brain cortex after transient focal cerebral ischemia induced by temporary occlusion of the middle cerebral artery (MCA) and the common carotid arteries (CCAs). Results indicate a large decrease (52%) in IP3R mRNA levels in the ischemic cortex as compared to that in the contralateral side at 4 h after a 45 min ischemic insult. By 16 h, practically no IP3R mRNA could be detected in the ischemic cortex. On the other hand, IP3K mRNA levels remained unaltered until 16 h after reperfusion, during which time, expression in the infarct core decreased but that surrounding the core area increased instead. Hybridization of adjacent brain sections with probes for neuron specific enolase (NSE) and beta-actin indicated also a time-dependent decrease in mRNA levels after ischemia, but these changes were less dramatic as compared to IP3R. At 16 and 24 h after reperfusion, there was an increase in beta-actin mRNA in cortical areas outside the MCA cortex, suggesting of reactive gliosis.(ABSTRACT TRUNCATED AT 250 WORDS)

[A cohort study and KAP investigation of HIV infected persons in Ruili, and other counties in Yunnan, 1994]

In 1994, an cohort study of drug users had continued in Longchuan and Luxi counties, Ruili city. The cohort study for drug users had been established since 1992 and total 522 drug users were investigated. Sixty five sera samples were collected, including 26 HIV negatives intravenous drug users in 1992 and 39 of them in 1993. The result shown that 10 sera samples are positives. Of sixty five samples tested, the rate of HIV infectious for IVDU in Ruili, Longchuan and Luxi were 25.0%, 16.3% and 0.0% respectively. Total of 46 HIV positives samples were found from 105 blood samples among the IVDU who were newly included in the cohort study in 1994. Of these samples, the rates of HIV infection in Ruili, Longchuan and Luxi were 61.8%, 38.5% and 0.0% respectively. The result of KAP investigation from 522 drug users has shown that there is a marked difference of the rate of HIV infections in the nationalities, occupations, education (P < 0.01). The main reason contributing the low rate of HIV infections in Luxi county is that the IVDU mainly are the Han nationality with higher education level, as well as travelling less to Burma.

Free fatty acids, neutral glycerides, and phosphoglycerides in transient focal cerebral ischemia

Cerebral ischemia is known to cause an increase in levels of free fatty acids (FFAs) and diacylglycerols (DGs), although the mechanism(s) leading to these changes is not well understood. In this study, we examined FFA and DG levels along with those of other lipids in rats during and after transient focal cerebral ischemia induced by temporary occlusion of the right middle cerebral artery (MCA) and both common carotid arteries. During the duration of ischemia (15-60 min), there was a time-dependent increase (two- to 10-fold) in FFA levels in the right MCA cortex, whereas levels of DG and other lipids were not altered appreciably. FFA levels in right MCA cortex returned to near control values after reperfusion. However, following a 60-min ischemic insult, there was a second phase of FFA level increase that was evident after 16 h. The FFAs accumulated during the ischemia period were different from those after reperfusion, suggesting differences in mechanisms for their release. During the second phase of FFA release, there were increases in levels of DGs and triacylglycerols (TGs) with unusually high proportions of 20:4(n-6) and 22:6(n-3). The increases in FFA, DG, and TG levels were marked by a decrease in content of phosphoglycerides (PGs). It is interesting that the increases in levels of FFAs and neutral glycerides accounted only for 10% of the total PGs depleted. The lipid changes during this reperfusion period correlated well with the development of cortical infarct.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of xue guan tong on PDGF-A, PDGF-B and c-myc gene expression of vessel wall in atherosclerotic rabbits]

In this study, the effect of Xue Guan Tong (XGT) on platelet-derived growth factor-A (PDGF-A), PDGF-B and c-myc gene expression of vessel wall was explored with dot blot and in situ hybridization. The results shown that the expression of PDGF-A mRNA in atherosclerotic plaque of the model group was higher, PDGF-A gene hybridizations were mainly distributed in smooth muscle cell which located in newly emerging plaque and edge of atherosclerotic plaque. In contrast, level of PDGF-A mRNA in the XGT group was lower than that in the model group, which indicated that XGT could influence the level of PDGF-A mRNA. The c-myc oncogene expression in the model group was significantly enhanced than that in the normal group. However, the expression in XGT group decreased less than that in the model group. From the results shown above, it suggested that one of the effects of XGT on preventing VSMC proliferation was its influence on PDGF-A and c-myc mRNA expression level.

Cohort study of HIV infection among drug users in Ruili, Longchuan and Luxi of Yunnan Province, China

In March 1992, KAP investigation and HIV blood test were carried out for 860 drug users and 82 spouses in Ruili, Luxi, Longchuan of Yunnan Province, China. The results showed that there were 285 injecting drug users (IDUs) (33.1%) among 860 drug users. Among 282 blood samples of IDUs, the HIV infection rate was 49.0%, highest in Ruili (81.8%, 63/77), then Longchuan (44.6%, 74/166), lowest in Luxi county (5.1%, 2/39). Twelve new HIV(+) were found from 75 persons, who had been tested as HIV(-) in recent two years. Sixty-two blood samples were collected among 82 spouses of IDUs with HIV(+), and 6 were HIV(+) (9.8%), with an increase of 6.7% compared with results of the investigation two years ago (3.1%, 2/64).

Effect of esculentoside H on release of tumor necrosis factor from mouse peritoneal macrophages

Effect of esculentoside H (EH) on release of tumor necrosis factor (TNF) from murine peritoneal macrophage (Mphi) in vitro was studied. The results showed that EH (12.5-200 micrograms.ml-1) induced the thioglycolate-broth elicited peritoneal Mphi to release TNF into supernatants in a dose-dependent manner, and higher levels of TNF activity were detected in the supernatants from EH-stimulated calcimycin-primed Mø culture. EH-induced TNF release had a different type of kinetics compared with that of lipopolysaccharides (LPS). LPS-induced release of TNF increased rapidly until 6 h after LPS stimulation, then declined gradually, while EH-induced TNF release increased gradually after EH stimulation and reached its peak at approximately 24 h later. These results suggested that the anti-tumor mechanisms of Phytolaccaceae may be related to the capacity of EH for TNF release.

Antitumor activity and tumor necrosis factor production of Phytolacca acinosa polysaccharides I in mice

The antitumor activities of Phytolacca acinosa polysaccharides I (PAP-I) and its effects on the induction of tumor necrosis factor (TNF) and immunological cytotoxicity of peritoneal macrophages were studied. PAP-I was given ip 5-20 mg.kg-1.d-1 x 7 d to ICR mice as priming agent with subsequent lipopolysaccharides (10 micrograms/mouse) iv for TNF production. TNF activity was measured by crystal violet staining assay using L929 cells. PAP-I showed priming activity for TNF production with hepto-splenic hyperplasia in a dose-dependent manner. The peritoneal macrophages treated with PAP-I 10 and 20 mg.kg-1 showed 67 and 74%, respectively, cytotoxicity (the control 34% cytotoxicity) against Meth A cells at effector:target = 40:1. PAP-I 10 and 20 mg.kg-1 prolonged the survival time of mice bearing ascites Meth A tumor from 21 +/- 4 to 32 +/- 10 and 38 +/- 8 d and inhibited the solid Meth A tumor growth with inhibition rate of 28.5 and 55.7%, respectively. These results suggested that the antitumor activities of PAP-I were based on the activation of macrophages and induction of TNF.

The cholinergic receptor-linked phosphoinositide metabolism in mouse cerebrum and cerebellum in vivo

The cholinergic receptor-linked poly-phosphoinositide hydrolysis was studied in mouse cerebrum and cerebellum after prelabeling the brain with [3H]inositol. I.p. injection of Li (8 meq/kg) to C57Bl/6J mice for 4 h resulted in 14- and five-fold increases in [3H]inositol-labeled inositol monophosphate (IP1) in cerebrum and cerebellum, respectively. The labeled inositol bisphosphate (IP2) was also increased 83 and 19% in cerebrum and cerebellum, respectively. Prior injection of atropine (100 mg/kg) resulted in inhibition of Li-induced increases in labeled IP1 by 74 and 56% in cerebrum and cerebellum, respectively. Administration of pilocarpine (20 mg/kg) to the Li-treated mice for 30 min resulted in further increases in labeled IP1 and IP2 and a concomitant decrease in labeled inositol in cerebrum but not in cerebellum. Mass measurements of IP1 and IP2 isomers by HPLC revealed that inositol 1-monophosphate (Ins(1)P), inositol 4-monophosphate (Ins(4)P) and inositol 1,4-bisphosphate (Ins(1,4)P2) were all increased by pilocarpine administration in the Li-treated mouse cerebrum. The effects of pilocarpine administration in mouse cerebrum (increases in IP1 and IP2) could be completely inhibited by preinjection of atropine. Atropine injection also decreased the levels of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. Surprisingly, a decrease in Ins(1,4,5)P3 level was also found in non-Li-treated mice after pilocarpine administration (30 mg/kg, 10-40 min). Except for the increase (20%) in [32P]-labeled PIP in the cerebrum, Li or Li together with pilocarpine administration did not alter the levels of [3H]inositol or [32P]phosphate-labeled phosphoinositides.(ABSTRACT TRUNCATED AT 250 WORDS)

[Inhibitory effects of protein kinase C inhibitor and calmodulin antagonist on tumor necrosis factor production by mouse macrophages]

Mouse peritoneal macrophages were primed with calcium ionophore calcimycin 1 mumol.L-1 for 8 h and then elicited by lipopolysaccharides (LPS, 10 ng.ml-1) for 6 h to induce tumor necrosis factor (TNF), measured by crystal violet staining assay using murine fibroblast L929 cells. Protein kinase C (PKC) inhibitor, 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7) and calmodulin (CaM) antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) were studied on LPS-induced TNF production by macrophages. Addition of H-7 (0.31-50 micrograms.ml-1) and W-7 (10-4000 ng.ml-1) simultaneously with LPS to the culture medium suppressed LPS-induced TNF production in a concentration-dependent manner. When macrophages were pretreated with W-7 (10 ng.ml-1), LPS-induced TNF production was completely inhibited at 8 h. These results suggest that TNF production by macrophages may be dependent on the PKC and CaM.

Metabolism of inositol 1,4,5-trisphosphate in mouse brain due to decapitation ischemic insult: effects of acute lithium administration and temporal relationship to diacylglycerols, free fatty acids and energy metabolites

Previous studies have shown that global cerebral ischemia induced by decapitation leads to the stimulated hydrolysis of poly-phosphoinositides. In this study, the decapitation model was used to further examine the temporal events related to metabolism of Ins(1,4,5)P3 and the release of diacylglycerols (DGs) and free fatty acids (FFAs) in the mouse brain. Since lithium administration is known to inhibit inositol monophosphatase activity in brain, the effects of acute lithium injection on Ins(1,4,5)P3 metabolism were also examined. Cerebral ischemia induced by decapitation of C57 Bl/6J mice resulted in transient increases of Ins(1,4,5)P3, Ins(1,4)P2 and Ins(4)P which peaked at 35, 65 and 125 s, respectively. The level of Ins(1)P, however, was not altered. Mice administered lithium by intraperitoneal injection (8 meq/kg for 4 h) gave rise to a 40- and 4-fold increase in levels of Ins(1)P, Ins(4)P, respectively, a 20% increase in levels of Ins(1,4)P2 but no apparent changes in the levels of Ins(1,4,5)P3. Decapitation also induced an increase in the levels of DGs and FFAs. Unlike the transient appearance of Ins(1,4,5)P3, however, DG levels increased steadily for 2 min and then reached a plateau whereas the FFAs showed a lag time of 35 s prior to a biphasic increase. During the initial 2 min after decapitation, there was a preferential increase in the DG species containing 18:0 and 20:4. Lithium administration did not alter the decapitation-induced release of DG and FFA. As expected, decapitation gave rise to a rapid decrease in the levels of phosphocreatine and ATP and the decline in ATP was marked by a transient appearance of ADP and a concomitant increase in AMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of C. trachomatis attachment to eukaryotic host cells

A novel trimolecular mechanism of microbial attachment to mammalian host cells was characterized for the obligate intracellular pathogen Chlamydia trachomatis. Using purified glycosaminoglycans (GAGs) and specific GAG lyases, we demonstrated that a heparan sulfate-like GAG present on the surface of chlamydia organisms is required for attachment to host cells. These observations were supported by inhibition of attachment following binding of heparan sulfate receptor analogs to chlamydiae and by demonstrating that chlamydiae synthesize a unique heparan sulfate-like GAG. Furthermore, exogenous heparan sulfate, as an adhesin analog, restored attachment and infectivity to organisms that had lost these attributes following treatment with heparan sulfate lyase. These data suggest that a GAG adhesin ligand mediates attachment by bridging mutual GAG receptors on the host cell surface and on the chlamydial outer membrane surface.

The possible mechanism of binding interaction of insulin molecule with its receptor

Detailed structural comparisons and investigation of DPI, 2 Zn insulin and some other derivatives of insulin were performed by the least-squares superimposition technique and the graphics technique. It is pointed out in this paper that the binding interaction with the receptor molecule should take place mainly on an amphipathic surface of the insulin molecule. In the middle, there is a hydrophobic surface with an area of about 150 A2 consisting of many hydrophobic residues; while the polar or charged groups distributing around the hydrophobic surface construct a hydrophilic zone. The hydrophobic surface is usually covered by the extended B-chain C-terminal peptides with great mobility and protected from the solvent molecules. The angle between the amphipathic surface and the surface of dimerization is about 20 degrees. The results from the detailed structural comparison between Al-(L-Trp) insulin and Al-(D-Trp) insulin have provided a very good explanation to their great difference in biological activity, and confirmed our proposed binding interaction model of the insulin molecule with its receptor as well.

Effects of cantharidin on interleukin-2 and interleukin-1 production in mice in vivo

After cantharidin (0.75, 1.5 mg.kg-1) was given ip 3 times every other day in mice, Con A-induced spleen lymphocyte proliferation, as measured by [3H]TdR incorporation assay, was enhanced from 7,978 +/- 1,780 to 36,631 +/- 8,467 and 29,997 +/- 3,788 dpm in both doses. Interleukin-2 and interleukin-1 production were also increased from 11 +/- 4 to 52 +/- 18, 23 +/- 6 U.ml-1 and from 7,628 +/- 1,477 to 14,532 +/- 2,272, 11,515 +/- 2,862 dpm, respectively. These results suggest that cantharidin potentiates immune response through the release of interleukin-2 and interleukin-1.

The characteristics and motion model of insulin monomer

The extensive conformational comparisons among the determined structures of the different species and crystal forms of insulin and the varied insulin derivatives were performed by using the least-squares superimposition technique and the graphics technique. The results of the investigation showed that the structure of molecule I in 2Zn insulin was closer to that of the natural monomer; the conformational difference between two molecules of a dimer came out during dimerization and it was further improved and stabilized during the hexamerization and packing of hexamers in crystal; through the hinge peptides, such as A10, B4, B8, B24, B20 and B23, there was a flexible relative motion among the structural segments in the insulin molecule, and the residues at the B-chain C-terminal might have a shift of more than 10A; the mobility for each residue side-chain was very different due to the different surroundings.

Progressive modifications of mouse lens crystallins in cataracts induced by buthionine sulfoximine

L-buthionine-S,R-sulfoximine (BSO), a specific inhibitor of GSH biosynthesis, was administered four times daily to mouse pups on post-natal days 7 and 8, inducing initiation of opacification on day 9. The initial progression of the cataract (less than 24 hr) was divided into four stages: (1) developing floriform; (2) mature floriform; (3) degenerate floriform; and (4) amorphous translucent cataract. Following this, dense corticonuclear opacities developed within several days. Two-dimensional gel electrophoresis of water-soluble whole lens extracts indicated that the most rapid early cataractous changes, occurring mainly during stage 2, were loss of the two major components of the heavy beta-crystallin fraction, a 31-kDa basic polypeptide and an acidic component at 27 kDa, concomitant with the appearance of new species at 30 and 25 kDa. This was followed by more extensive modification of both alpha and beta-crystallins during stages 3 and 4 and the appearance of abnormal species at 26, 19 and 18 kDa, which were slightly more acidic than the major normal alpha A-crystallin polypeptide. The gamma-crystallin components, relatively unaffected at stage 4, were then lost rapidly as dense opacities ensued. By contrast with the water-soluble fraction, the normal day 9 urea-soluble fraction was deficient in gamma-crystallin polypeptides and enriched in anodic components whose relative electrophoretic mobilities were similar to those reported previously for phosphorylated bovine alpha A-crystallin and several cytoskeletal polypeptides. At stage 4 of the cataract, the modifications of normal alpha and beta-crystallin components in the urea-soluble fraction paralleled those in the water-soluble fraction, but the products seen were more numerous. In addition, the cytoskeletal proteins were no longer detectable. Substantial increases in lens Ca2+ that precede all of the above changes in lens polypeptide composition suggest that Ca(2+)-activated proteolysis may play a major role in development of BSO cataracts.

[Changes in leucocytic estrogen receptor levels in patients with climacteric syndrome and therapeutic effect of liuwei dihuang pills]

The numbers of estrogen receptor (ER) in human peripheral leucocytes in 22 women with climacteric syndrome were measured by radioligand method. The results were compared with those of 12 normal child-bearing-age women. It wat found that the contents of leucocytic ER in climacteric syndrome patients were significantly lower than normal child-bearing-age women. The authors used a Chinese prescription--Liuwei Dihuang Pills (LDP) to treat the patients for 2 months. The numbers of leucocytic ER were significantly increased after treatment. The data indicate that decrease of ER levels in cell may involve in the pathogenesis of climacteric syndrome. LDP not only increases plasma estradiol levels, but also increases the leucocytic ER levels. This may be the basis of the therapeutic effect on the disease.

[An epidemiological study on HIV infection in Ruili county Yunnan Province]

The study of 2530 persons in Ruili county for HIV infection showed that the high-risk population were drug users and the wives of infected persons. The introvanous drug users (IVDUs) have been seriously infected by the highest rate of 67.98%. The sexual transmission male to female have occurred, and 2 out of 64 wives of infected husbands (3.13%) were affected. Seventy-five Burmese were examined and 10 (13.3%) were positives. No positive was found in other population including prostitutes, waiters and waitress of hotel, doctors, clinic patients and blood donors etc.

[Effects of Phytolacca acinosa polysaccharides I on cytotoxicity of macrophages and its production of tumor necrosis factor and interleukin 1]

The in vivo effects of Phytolacca acinosa polysaccharides I (PEP-I) on immunologic cytotoxicity of mouse peritoneal macrophages and its production of tumor necrosis factor (TNF) and interleukin 1 (IL-1) were studied. PEP-I 80, 160 mg/kg was given ip twice every 4 d. Both doses were found to have significant enhancing activity on macrophages cytotoxicity against S180 sarcoma cells and malignant transformed fibroblast L929 cells. Peritoneal activated macrophages were incubated with LPS for 2 and 24 h to induce TNF and IL-1, respectively. The TNF and IL-1 activities were tested from cytotoxicity against L929 cells in an absorbance assay of enzymatic reaction and proliferation of thymocytes co-stimulated assay separately. The optimal time for TNF production was found on d 8. Significant increases in TNF and IL-1 were observed. In comparison of the effect of PEP-I on TNF with that of known priming agent BCG, there was no difference between these two, but PEP-I had a high effect on IL-1. These results suggest that cytotoxicity of macrophages primed by PEP-I is closely related to its TNF and IL-1 production.

Differential effects of galactose-induced cataractogenesis on the soluble crystallins of rat lens

Soluble lens crystallins from 6-10-week-old, galactose-fed, male Sprague-Dawley rats were analyzed by two-dimensional polyacrylamide gel electrophoresis at each of the five Sippel stages of cataractogenesis. Electrophoretograms were compared with similarly analyzed crystallins from comparably aged, chow-fed controls. Polypeptides were assigned to crystallin families and subfamilies on the basis of chromatographic fractionations with Sephadex G-200, superfine. Staining intensities of polypeptides from control lenses remained essentially unchanged throughout the experimental period, while those of the polypeptides from cataractous lenses showed non-uniform changes. Staining of the genomic gamma-crystallins increases up to at least stage 3; by stage 4, staining of gamma-chains, with perhaps those of gamma 5 and gamma 6 excepted, diminishes and in the total cataract, staining of all chains is further reduced. With possibly the addition of one chain, the total number of postsynthetically modified gamma-crystallins in cataractous lenses does not exceed that in the comparably aged normal lens. The genomic alpha- and beta-crystallin polypeptides are sustained close to normal levels up to stages 3 or 2, respectively, after which their gradually falling levels are accompanied by the generation of new species or elevated levels of existing post-translational species. An exception to this behavior is the rapid and total loss of beta B1a, a genomic subunit implicated in the aggregation of beta H-crystallins. Charge heterogeneity and variable pI displayed by beta B1a and other highly cationic beta- and gamma-crystallin polypeptides can be induced during isoelectric focusing and may be due to thiol group oxidation.

Crystal structure determination of desheptapeptide (B24--B30)-insulin

Desheptapeptide (B24--B30)-insulin (DHPI), an essentially inactive insulin analog, is crystallized in space group P212121 with two molecules in an asymmetric unit. The orientations of the molecules in the crystal cell have been determined by using Patterson search method at 6 A resolution and the positions of the molecules are deduced from translation function calculation and R search at 3 A resolution. After using the rigid body refinement (CORELS) further to refine the orientational and positional parameters as well as the initial energy restrained refinement (EREF) for the model, the crystallographic R value is reduced to 0.384 at 3 A resolution. The initial Fourier map shows that the B-chain N-terminal (B1-B8) and C-terminal (B20-B22) segments, compared with the native 2 zinc insulin, exhibit drastic conformational changes, but the three helices of B- and A-chains and their relative arrangement are essentially kept in DHPI.

Paraplegia caused by local spinal cord ischemia. An animal spinal cord ischemia model

Local spinal cord ischemia model was established in 11 adult dogs. The anterior spinal artery, posterior spinal artery and radicular artery were cauterized with bipolar cautery. Ischemia of this segment of spinal cord was thus produced followed by paraplegia. The pathological findings of this spinal cord segment were softening and necrosis. The establishment of this animal model of segmental spinal cord ischemia is beneficial to scientific research in basic medicine and clinical practice.

[Experimental studies of hyperlipidemia in rats and mice given a hyperlipidemic diet]

Hyperlipidemia in rats and mice was induced by hyperlipidemic diet containing 1.5% cholesterol, 0.25% cholic acid, 7.5% lard and 90.75% essential diet. After feeding for 7 days, the serum cholesterol levels in the experimental group are about 5 times higher than that in the control group. It appears that there exist similarities between rats and mice and that these models may be used for screening tests of hypolipidemic drugs.

High-resolution electron microscopy of high-temperature superconductors

We review recent results obtained at Northwestern using high-resolution electron microscopy to study high-temperature superconductors. While in general these materials form large, very perfect single crystal grains which display very few imperfections, there is also evidence of slip defects, amorphous regions, and order-disorder transformations. We also report that the gadolinium-based superconductors and in one case yttrium-based superconductors show evidence for some copper solid solubility in the form of copper-rich planar defects. The structure of a metastable trigonal polytype is also reported, as are the effects of electron beam and water vapor damage to the materials.