Local hemodynamic changes during transient middle cerebral artery occlusion and recirculation in the rat: a [14C]iodoantipyrine autoradiographic study

We evaluated acute alterations of local cerebral perfusion following 30 min of transient right proximal middle cerebral artery (MCA) clip-occlusion in the rat and following two intervals of postischemic reperfusion. Local cerebral blood flow (lCBF) was assessed by [14C]iodoantipyrine autoradiography. Brain temperature was controlled at 35.5-36.5 degrees C throughout the experiment. We measured lCBF in four groups of rats: (a) sham-operated controls (n = 5), (b) following 30 min MCA occlusion (n = 5), (c) following 30 min of MCA occlusion with 15-min reperfusion (n = 6) and (d) following 30 min of MCA with 120-min reperfusion (n = 6). lCBF was measured in seven regions of the ischemic and non-ischemic hemispheres. MCA occlusion induced an ipsilateral reduction of lCBF, which was most severe in the parietal cortex (8.4 +/- 4.0% of control, mean +/- S.D.), and dorsolateral caudoputamen (20.0 +/- 13.4% of control). lCBF in the non-ischemic hemisphere and in ipsilateral regions lying outside the MCA territory also decreased significantly. lCBF recovery was incomplete when assessed following only 15 min of reperfusion. Reperfusion of 120 min led to return of cortical CBF to control levels, but lCBF in the caudoputamen remained depressed (50-55% of control values). Caudoputaminal CBF and cortical CBF values were highly correlated with one another under normal and ischemic conditions, but this correlation was disrupted following reperfusion. On the basis of these results, we speculate that, if a means were found to enhance the early recovery of lCBF following transient ischemia, this might expand the therapeutic window of opportunity for the institution of other neuroprotective strategies.

Calorie restriction modulates lymphocyte subset phenotype and increases apoptosis in MRL/lpr mice

Defective expression of the Fas apoptotic gene may account for overproduction of CD4- CD8- B220+ cells (double-negative) in MRL/MpJ-lpr/lpr (lpr) mice. Previous studies have shown that calorie restriction (CR) inhibits the development of autoimmune disease and extends life span in these animals. The present studies describe the effects of CR on the distribution of lymphocyte phenotypes, lymphocyte proliferative response, and cytokine release. The effects of CR on dexamethasone (DEX)-induced apoptosis were also studied using propidium iodide (PI) uptake and DNA fragmentation in splenocytes and lymph node (LN) cells. Weanling female mice were fed a nutritionally adequate semipurified diet either ad libitum (AL) or with 40% fewer calories than AL (CR), and killed at 5 months of age. CR mice had fewer palpable lymph nodes, and decreased serum anti-dsDNA antibodies. Mitogen (ConA, anti-CD3, and LPS) and superantigen (SEB)-induced proliferative response was significantly lower in lymphoid cells from AL fed animals. FACS analysis of cells from CR animals showed decreased CD4- CD8- cells in spleen (1.7-fold, P < 0.025) and LN (1.6-fold P < 0.01) and significantly higher CD4+ (spleen, 1.7-fold, P < 0.0001; LN, 2.6-fold, P < 0.025) and CD8+ (spleen, 1.6-fold, P < 0.001; LN, 5.2-fold, P < 0.005) cells. ConA-stimulated IL-2 release was increased in CR animals (splenocytes, 7.5-fold, P < 0.001; LN cells, 6.1-fold, P < 0.01). Finally, apoptosis in response to Dex was increased in CR animals as indicated by the presence of more PI-positive cells (spleen, 15.8%; LN, 10.7%; P < 0.01) and increased DNA fragmentation. In summary, the amelioration of autoimmune disease in MRL/lpr mice by CR is accompanied by prevention of the rise in 'double-negative' T cells and by maintenance of lymphocyte responsiveness to mitogens and DEX-induced apoptosis at higher levels.

Experimental autoimmune insulitis. Induction by T lymphocytes specific for a peptide of proinsulin

Type I diabetes, an autoimmune disease that occurs in humans and animals, is characterized by the destruction of insulin-secreting islet beta-cells of the pancreas. Antibodies directed toward multiple islet protein can be detected before diagnosis of type I diabetes; however, the identity of the inciting autoantigen(s) that targets beta-cells for destruction has not been defined. Autorecognition of many self-proteins by CD4+ T lymphocytes is restricted by the products of class II immune response genes of the major histocompatibility complex (MHC), and in human type I diabetes such a MHC association has been described. The present study uses a rat MHC class II (RT1.Bl) peptide binding motif to predict potentially autoreactive CD4+ T cell epitopes in two key islet beta-cell constituents: the enzyme glutamic acid decarboxylase (GAD) and the insulin precursor hormone proinsulin (PI). Seventeen-amino-acid-long peptide fragments of GAD and PI containing the binding motif were synthesized and used to generate peptide-specific, MHC class II-restricted, CD4+ T cell lines. Once established, the T cell lines specific for rat islet GAD and PI were adoptively transferred to naive, MHC-compatible rats. At 10 days after transfer, insulitis had developed in rats receiving PI-specific T cells, whereas no insulitis was observed in pancreata of rats receiving GAD-specific T cells. Of particular interest is the finding that the pathogenic T cell epitope identified in PI spans the endogenous cleavage site between the B-chain and C-peptide of insulin. Moreover, the PI-specific T cells were able to react specifically with material produced in vitro by a rat insulinoma cell line. These results demonstrate that pathogenic T cell epitopes can be located in portions of molecules that are subsequently degraded during normal enzymatic processing. As PI is found highest concentrations in the beta-cells of pancreatic islets, it is possible that this molecule and not its individual degradation products (ie, insulin and C-peptide) might serve as an autoantigen in the pathogenesis of type I diabetes.

Three-dimensional quantitative autoradiography by disparity analysis: theory and application to image averaging of local cerebral glucose utilization

Traditional autoradiographic image analysis has been restricted to the two-dimensional assessment of local cerebral glucose utilization (LCMRglc) or blood flow in individual brains. It is advantageous, however, to generate an entire three-dimensional (3D) data set and to develop the ability to map replicate images derived from multiple studies into the same 3D space, so as to generate average and standard deviation images for the entire series. We have developed a novel method, termed "disparity analysis," for the alignment and mapping of autoradiographic images. We present the theory of this method, which is based upon a linear affine model, to analyze point-to-point disparities in two images. The method is a direct one that estimates scaling, translation, and rotation parameters simultaneously. Disparity analysis is general and flexible and deals well with damaged or asymmetric sections. We applied this method to study LCMRglc in nine awake male Wistar rats by the [14C]2-deoxyglucose method. Brains were physically aligned in the anteroposterior axis and were sectioned subserially at 100-microns intervals. For each brain, coronal sections were aligned by disparity analysis. The nine brains were then registered in the z-axis with respect to a common coronal reference level (bregma + 0.7 mm). Eight of the nine brains were mapped into the remaining brain, which was designated the "template," and aggregate 3D data sets were generated of the mean and standard deviation for the entire series. The averaged images retained the major anatomic features apparent in individual brains but with some defocusing. Internal anatomic features of the averaged brain were smooth, continuous, and readily identifiable on sections through the 3D stack. The fidelity of the internal architecture of the averaged brain was compared with that of individual brains by analysis of line scans at four representative levels. Line scan comparisons between corresponding sections and their template showed a high degree of correlation, as did similar comparisons performed on entire sections. Fourier analysis of line scan data showed retention of low-frequency information with the expected attenuation of high-frequency components produced by averaging. Region-of-interest (ROI) analysis of the averaged brain yielded LCMRglc values virtually identical to those derived from measurements and subsequent averaging of data from individual brains.(ABSTRACT TRUNCATED AT 400 WORDS)

An in vitro EPR study of the free-radical scavenging actions of the lazaroid antioxidants U-74500A and U-78517F

Oxygen-based free radicals have been shown to play a major role in the acute destruction of neurons following cerebral ischemia and may be involved in the chronic neurodegeneration seen in Parkinson's disease, Alzheimer's disease, and other conditions characterized by the progressive death of neurons in the central nervous system. Drugs belonging to a group of antioxidant compounds, collectively known as the lazaroids, have strong neuroprotective effects in experimental models of acute ischemia. However, the specific mechanisms by which these drugs reduce the harmful actions of free radicals have not been established. Using electron paramagnetic resonance (EPR) spectroscopy with spin trapping, we investigated the interaction of U-74500A, a first-generation lazaroid, and U-78517F, a second-generation lazaroid, with two species of oxygen-based free radicals in aqueous solution and with the stable nitrogen-based free radical diphenylpicrylhydrazyl in dimethyl sulfoxide. Superoxide radicals were generated by the action of xanthine oxidase on hypoxanthine. Hydroxyl radicals were generated by the Fenton reaction involving aqueous ferrous iron and hydrogen peroxide. Both lazaroids reduce the EPR signal of all three radicals, but the drugs differ in potency and relative radical selectivity. These observations are consistent with the lazaroids being scavengers of oxygen-based and nitrogen-based free radicals and suggest that the neuroprotective actions of the lazaroids in cerebral ischemia may involve direct interactions of the lazaroids with several different species of free radicals.

Three-dimensional image analysis of brain glucose metabolism-blood flow uncoupling and its electrophysiological correlates in the acute ischemic penumbra following middle cerebral artery occlusion

The relationship between local cerebral glucose utilization (LCMRglc) and local CBF (LCBF) is known to be disturbed in regions surrounding an acute focal ischemic lesion--areas that undergo repeated transient depolarizations. In this study, we evaluated the relationship between LCMRglc and LCBF in the acute focal ischemic penumbra to quantify metabolism-flow uncoupling, and we related these findings to local electrophysiological measurements. A novel strategy utilizing three-dimensional (3D) autoradiographic image averaging yielded group 3D reconstructions of LCBF, LCMRglc, and the CMR/CBF ratio. The distal right middle cerebral artery of Sprague-Dawley rats was occluded by laser-driven photothrombosis following administration of the photosensitizing dye rose bengal; this was coupled with permanent ipsilateral and 1-h contralateral common carotid artery occlusions. LCBF (n = 7) and LCMRglc (n = 7) were measured autoradiographically at 1.25 and 1.5-2 h postocclusion, respectively, in matched animal groups. Within the ischemic penumbra (defined as having LCBF of 20-40% of control or 0.23-0.47 ml g-1 min-1), LCMRglc showed a heterogeneous pattern with values ranging from near normal to markedly increased. The resulting CMRglc/CBF ratio in this zone was 234 +/- 100 mumol/100 ml (mean +/- SD), representing a severe degree of metabolism-flow dissociation when compared with the CMRglc/CBF ratio of 51.0 +/- 28.7 mumol/100 ml of the contralateral (normal) hemisphere. Metabolism-flow uncoupling was confined to the ipsilateral cortex and was most prominent at the anterior and posterior coronal poles of the ischemic lesion. In the frontoparietal penumbra, where marked uncoupling was observed, sustained deflections of the DC potential were recorded, which increased significantly in duration over the initial 65 min postocclusion. Both the heterogeneous pattern of LCMRglc and the widespread distribution of increased CMRglc/CBF ratio in the ischemic penumbra are thought to reflect the metabolic consequences of periinfarct depolarizations. Analysis of averaged 3D autoradiographic data sets provides a powerful means for assessing metabolism-flow uncoupling surrounding an ischemic focus.

Evaluation of serum troponin T measurement in acute myocardial infarction

The release kinetics of the cardiac specific troponin T (cTnT), measured by an immunosorbent assay, in 32 patients with acute myocardial infarction (AMI) was evaluated. In 8 AMI patients (25%), the release kinetics of serum cTnT showed biphasic serum concentration curves with a large peak at 10 to 18 hours after onset and the serum cTnT concentrations were up to 30 to 120 times of the normal upper limit-detected (0.2 microgram/ml), and another samll cTnT peak at 70 to 100 hours after onset of pain. The serum cTnT measurements in the remaining 24 AMI patients (75%) gave only one large peak which was around 32 to 108 hours after onset of pain. cTnT appeared in serum as early as 3 to 4 hours and remained elevated until 240 hours after the infarctions. The results indicated that (1) cTnT was a sensitive and specific marker of AMI; (2) the biphasic curve of cTnT releae in general, the ratio of cTnT at around 14 to 32 (14/32) > 1 in particular, may be a useful marker suggesting early reperfusion; (3) the continuous elevation of serum cTnT in AMI course might be a prognostic indicator for unfavorable outcomes.

Pleckstrin inhibits phosphoinositide hydrolysis initiated by G-protein-coupled and growth factor receptors. A role for pleckstrin's PH domains

Pleckstrin is a 40-kDa protein present in platelets and leukocytes that contains two PH domains separated by a 150-residue intervening sequence. Pleckstrin is a major substrate for protein kinase C, but its function is unknown. The present studies examine the effects of pleckstrin on second messenger generation. When expressed in cos-1 or HEK-293 cells, pleckstrin inhibited 1) the G alpha-mediated activation of phospholipase C beta initiated by thrombin, M1-muscarinic acetylcholine, and angiotensin II receptors, 2) the stimulation of phospholipase C beta by constitutively active Gq alpha, 3) the G beta gamma-mediated activation of phospholipase C beta caused by alpha 2A-adrenergic receptors, and 4) the tyrosine phosphorylation-mediated activation of phospholipase C gamma caused by Trk A. However, pleckstrin had no effect on either the stimulation or inhibition of adenylyl cyclase. The inhibition of phosphoinositide hydrolysis caused by pleckstrin was similar in magnitude to that caused by activating protein kinase C with phorbol 12-myristate 13-acetate (PMA). When combined, pleckstrin and PMA had an additive effect, inhibiting phosphoinositide hydrolysis by as much as 90%. Structure-function analysis highlighted the role of pleckstrin's N-terminal PH domain in these events. Although deleting the C-terminal PH domain had no effect, deleting the N-terminal PH domain abolished activity (but not expression) and mutating a highly conserved tryptophan residue within the N-terminal PH domain decreased activity by one-third. Notably, however, a pleckstrin variant in which the N-terminal PH domain was replaced with a second copy of the C-terminal PH domain was nearly as active as native pleckstrin. These results show that: 1) pleckstrin can inhibit pathways leading to both phospholipase C beta- and phospholipase C gamma-mediated phosphoinositide hydrolysis, 2) this inhibition affects activation of phospholipase C beta mediated by either G alpha or G beta gamma, but does not affect the regulation of adenylyl cyclase activity by G alpha or G beta gamma, 3) although pleckstrin is a substrate for protein kinase C, the effects of pleckstrin and PMA are at least partially independent, 4) the inhibition caused by pleckstrin appears to be mediated by the PH domain at the N terminus, rather than the C terminus of the molecule, and 5) location of the two PH domains within the molecule clearly contributes to their individual activity.2+1

[Detection of p53 mutation using PCR-SSCP silver staining method]

A simple and sensitive technique to detect point mutation of the p53 gene using silver staining method for single-strand conformation polymorphism analysis of polymerase chain reaction (PCR-SSCP) is reported. In this study, the aberrations of the p53 gene (exon 6-8) in clinical specimens of primary cervical carcinoma were examined. Of 27 tumor tissues 2 samples showed mutations of p53 exon 7. Absence of abnormal bands in the p53 exon 6-8 in all ten normal cervical tissues. It appears that inactivation of p53 gene by point mutation is infrequent in clinical samples of human cervical carcinomas.

Inhibition of DNA synthesis in primary cultures of adult rat hepatocytes by benzo[a]pyrene and related aromatic hydrocarbons: role of Ah receptor-dependent events

Studies were conducted to examine the effects of benzo[a]pyrene (BaP) and related-aromatic hydrocarbons (AHs) on the DNA synthetic profiles of adult rat hepatocytes in primary culture. Scheduled DNA synthesis in control cultures peaked at 64 h and was negligible by 72 h after initial seeding of freshly isolated hepatocytes. A concentration-dependent inhibition of DNA synthesis was observed in 1-day old hepatocyte cultures treated with BaP (0.3-30 microM) for up to 28 h. Comparable inhibitory responses were observed in cultures treated for 24 h with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 0.01-1 nM) or 2,3,7,8-tetrachlorodibenzofuran (TCDF, 0.01-1 nM), but not in cultures treated with perylene (0.01-100 nM) or benzo[e])pyrene (1-1000 nM). Ethoxyresorufin-O-deethylase (EROD) activity was highly inducible in hepatocytes challenged for 24 h with BaP (0.3-3 microM) or TCDD (0.1-100 nM) with peak induction observed at 12 or 36 h after chemical challenge, respectively. To determine if DNA synthesis inhibition by these agents involved aryl hydrocarbon receptor (AhR)-related events, subsequent experiments were conducted to examine the interactions of alpha-naphthoflavone (alpha-NF) and ellipticine (ET) with BaP and TCDD in this cell system. Pretreatment with alpha-NF (10 nM) for 24 h prevented the inhibitory effects of both BaP (3 microM) and TCDD (1 nM), while ET (0.01 nM) pretreatment selectively antagonized the effects of BaP (3 microM). Pretreatment of hepatocytes with TCDD or TCDF (1 nM) for 24 h before the onset of DNA synthesis followed by challenge with BaP (3 microM) partially antagonized the inhibitory response to BaP. These data implicate AhR-related signal transduction in the inhibition of hepatocyte DNA synthesis by BaP and related AHs and suggest that in the case of BaP, metabolism by cytochrome P450 to toxic intermediates contributes to the inhibitory response.

Effect of nitric oxide on in vitro responsiveness of bovine bronchus and pulmonary vessels

Experiments were conducted in bovine isolated bronchi and pulmonary vessels to test whether nitric oxide (NO) could reduce carbachol and hypoxia or KCl (120 mM) induced contraction. Segments of bronchus or pulmonary vessels were slipped around a water-filled balloon connected to a pressure transducer, and mounted in 3 ml thermostated chamber filled with Krebs-Henseleit solution equilibrated with different gas mixtures. NO-CO2-N2 mixtures containing 10, 50 or 100 ppm NO were prepared. The effect of methylene blue on intrinsic tone and the bias effect of residual red blood cells were assessed. The results demonstrate that NO has no obvious effect on the intrinsic tone, the force generated by carbachol stimulation, or the spontaneous relaxation after removal of carbachol, in bronchi, with the exception of 100 ppm which increased the relaxing rate in small bronchi. By contrast, 50 and 100 ppm NO caused 53 and 61% decrease in the hypoxia-induced pulmonary arterial contraction, respectively. One hundred ppm NO caused 40, 38, 50 and 66% decrease in the KCl-induced contraction in pulmonary artery (PA), small pulmonary artery (SPA), small pulmonary vein (SPV) and pulmonary vein (PV), respectively. Sodium nitroprusside (10(-5) M) and isoproterenol (10(-5) M) reduced the carbachol-induced increase in bronchial pressure by 80% and nearly 100%, respectively. The residual concentration of haemoglobin in the chamber cannot explain the lack of effect of NO on the bronchi.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of nitric oxide on in vitro responsiveness of bovine bronchus and pulmonary vessels

Experiments were conducted in bovine isolated bronchi and pulmonary vessels to test whether nitric oxide (NO) could reduce carbachol and hypoxia or KCl (120 mM) induced contraction. Segments of bronchus or pulmonary vessels were slipped around a water-filled balloon connected to a pressure transducer, and mounted in 3 ml thermostated chamber filled with Krebs-Henseleit solution equilibrated with different gas mixtures. NO-CO2-N2 mixtures containing 10, 50 or 100 ppm NO were prepared. The effect of methylene blue on intrinsic tone and the bias effect of residual red blood cells were assessed. The results demonstrate that NO has no obvious effect on the intrinsic tone, the force generated by carbachol stimulation, or the spontaneous relaxation after removal of carbachol, in bronchi, with the exception of 100 ppm which increased the relaxing rate in small bronchi. By contrast, 50 and 100 ppm NO caused 53 and 61% decrease in the hypoxia-induced pulmonary arterial contraction, respectively. One hundred ppm NO caused 40, 38, 50 and 66% decrease in the KCl-induced contraction in pulmonary artery (PA), small pulmonary artery (SPA), small pulmonary vein (SPV) and pulmonary vein (PV), respectively. Sodium nitroprusside (10(-5) M) and isoproterenol (10(-5) M) reduced the carbachol-induced increase in bronchial pressure by 80% and nearly 100%, respectively. The residual concentration of haemoglobin in the chamber cannot explain the lack of effect of NO on the bronchi.(ABSTRACT TRUNCATED AT 250 WORDS)

[Studies on diagnosis for occupationally chronic toxic hepatopathy]

Data from 10-to-17-year periodical physical examinations for 10,858 employees exposed to hepatotoxic chemicals were sorted out and analyzed, and 1,514 cases of suspected chronic toxic hepatopathy were detected. Causes of under-recognition of those were: (1) liver function tests now available being not sensitive enough; (2) limitations of conventional methods for diagnosis of hepatopathy by excluding other disorders; and (3) lack of diagnostic criteria for it. In the light of existing problems, the following diagnostic procedures were applied in the studies: (1) analyzing data dynamically to understand when and to what extent the liver damaged during their work; (2) exploring several more sensitive liver function tests to be used in the diagnosis, and (3) incorporating industrial hygienic files into clinical data to get preliminary diagnosis for it, and then to differentiate from other disorders and to establish a definite conclusion. With these procedures, diagnosis of occupationally chronic toxic hepatopathy was established in 1,035 cases of 1,514 suspected ones.

An interferon-inducible molecule on brain endothelium which controls lymphocyte adhesion mediated by integrins

We undertook a search for cytokine-inducible molecules present on brain endothelium and which are involved in the control of lymphocyte adhesion. We screened 39 monoclonal antibodies (mAb) against rat brain endothelium in vitro, and identified five recognizing cytokine-inducible molecules. None of the 39 antibodies blocked lymphocyte adhesion, but one antibody (4A2), produced a 400% enhancement of lymphocyte binding. The 4A2 antigen is induced on brain endothelium by interferon-gamma (INF-gamma) but not tumour necrosis factor-alpha (TNF-alpha), at 6-48 hr. It is preferentially expressed near inter-endothelial cell junctions, but it also expressed on all lymphocytes and weakly on aortic endothelium in vitro. In vivo, it is not detectable on cells in the normal central nervous system (CNS), however it appears in the CNS during T-cell mediated immune reactions. Triggering of cells via this molecule enhances integrin-mediated adhesion of lymphocytes to brain endothelium, primarily via LFA-1. Unlike ICAM-1, 4A2 antigen is induced on endothelium of both Lewis and PVG strains. Although, it has some functional properties of human CD31, the 4A2 antigen is not rat CD31. The cellular localization of this molecule, its actions on integrin-mediated adhesion and its induction by IFN-gamma, all indicate that the 4A2 antibody recognizes a molecule involved in the control of lymphocyte migration into the brain.

Bone regrowth in young mice stimulated by nail organ

Recent studies of postamputational repair following digit-tip amputation revealed an unexpected correlation between nail regrowth and bone regrowth in mice. To examine putative effects of nail on bone regrowth, phalangeal tips were amputated such that nail was artificially removed from distal levels or retained following proximal level amputations. In the absence of nail, bone did not regrow at distal levels. Conversely, when nail was surgically retained bone regrew from proximal levels. The nail organ profoundly influences bone regrowth.

Bibenzyls from Stemona tuberosa

Three new bibenzyls were isolated from the roots of Stemona tuberosa. Their structures were identified by spectroscopic methods as 3,5-dihydroxy-4-methylbibenzyl, 3,5-dihydroxy-2'-methoxy-4-methylbibenzyl and 3-hydroxy-2',5-dimethoxy-2-methylbibenzyl.

SH3 domains specifically regulate kinase activity of expressed Src family proteins

The Src homology 2 (SH2) and Src homology 3 (SH3) domain are approximately 50% conserved in various Src family kinase members. Several lines of evidence suggest that in Src these domains are sequence motifs that direct substrate recognition, regulate kinase activity, or control subcellular localization. We sought to investigate the function of the homology domains in human Lyn, and to determine whether the differences between various SH3 domains affect function. To do this, we generated variant forms of Lyn lacking SH2 and SH3 domains, and created chimeras in which the SH3 domains in human c-Src and Lyn were replaced with SH3 domains from other family members. In contrast to similar deletions in Src, forms of Lyn lacking SH2 or SH3 had decreased kinase activity. The SH3 chimeras all had individual characteristics. Insertion of the Blk SH3 domain into Lyn restored kinase activity, while insertion of the Fyn or Src SH3 into Lyn enhanced the kinase activity 2-3-fold. Insertion of the Lyn SH3 into Src also doubled kinase activity. Expression of the Lyn-Src SH3 chimera in mammalian cells induced cell transformation. This study 1) demonstrates that the regulation of Lyn is different than Src, and 2) provides new evidence that despite their homology, there are important functional differences between the SH3 domains of the various Src family members.

Phosphorylation changes following weakly reinforced learning and ACTH-induced memory consolidation for a weak learning experience

The formation of a protein synthesis-dependent long-term memory stage in day-old chicks trained on a passive discriminated avoidance task has been shown to occur only with an adequate level of reinforcement, and is preceded by a significant change in the phosphorylation state of the forebrain synaptosomal membrane protein GAP43 protein. In the present study, it is shown that weakly reinforced training did not lead to formation of a long-term memory stage or to any change in phosphate incorporation into forebrain P2M protein bands. However, administration of ACTH immediately posttraining led to both the formation of the long-term memory stage and a preceding significant increase in the phosphorylation of GAP43. These findings are consistent with the view that a reinforcement-dependent neurohormone-mediated change to the phosphorylation of this synaptosomal membrane protein may be implicated in the triggering of long-term memory consolidation.

Influence of different doses of methyl ethyl ketone on 2,5-hexanedione concentrations in the sciatic nerve, serum, and urine of rats

Rats were injected subcutaneously with 2,5-hexanedione (2,5-HD 2.6 m mol/kg) alone (HD group) or with 2,5-HD and methyl ethyl ketone (MEK) (2.6 m mol/kg of each agent, HD&MEK group) or with 2,5-HD 2.6 m mol/kg and 5 times that dose (13.0 m mol/kg) of MEK (HD&5MEK group). The concentration of 2,5-HD in serum and in the sciatic nerve was determined 0.5, 1, 2, 4, 8, and 16 h after administration. Urinary 2,5-HD concentration was determined from the beginning of administration up to 16 h afterward. 1) The concentration of 2,5-HD in the serum, the sciatic nerve, and the urine was increased significantly (p < 0.05) in the co-administered groups; the higher the MEK doses were, the greater was the increase. 2) The clearance of 2,5-HD from both the serum and the sciatic nerve was delayed in the co-administered groups. The highest concentration in serum and the sciatic nerve appeared at 1 and 2 h respectively. After administration, the biological halflife (t1/2) of 2,5-HD from 1 to 8 h in serum was 6.5, 5.8 and 12.0 h for the HD, HD&MEK, and HD&5 MEK groups respectively. From 8 to 16 h, the t1/2 in serum was 1.2, 3.2 and 16.6 h for the HD, HD&MEK, and HD&5MEK groups, respectively. In nerve tissue, the prolongation of clearance in the co-administered groups was greater than that in serum, the t1/2 from 2 to 8 h being 5.2, 9.6 and 19.9 h for the HD, HD&MEK, and HD&5MEK groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The impairment of long-term memory formation by the phosphatase inhibitor okadaic acid

While there is considerable evidence that protein kinase activity is involved in memory formation, there has been, as yet, no direct investigation of a role for protein phosphatases. However, phosphatases have been implicated in the effects of the activation of glutamate receptors of the NMDA type, in long-term depression, and in the regulation of transmitter release and membrane ion channel activities, phenomena which have been shown to be possibly involved in cellular memorial processes. In the present paper, inhibition of protein phosphatase by 0.5 nM okadaic acid, a selective inhibitor of phosphatases 1 and 2A, is demonstrated to prevent memory consolidation in day-old chicks trained on a single trial passive avoidance task. Retention losses first occurred after 30 min post-learning, at an intermediate stage of memory formation preceding a protein synthesis-dependent long-term stage. It is suggested that protein phosphatase activity is involved in precursor processes to long-term memory consolidation.

[Prognosis of Graves disease treated with different modalities of therapy]

A retrospective study on the prognosis of Graves disease was carried out. 224 cases, whose treatment has been stopped for 6 months to more than 10 years, were divided into 3 groups. 82 cases received long-term antithyroid drug therapy, 100 cases were treated with radioactive 131I and 42 cases had subtotal thyroidectomy. The prognosis was evaluated for 4 items according to clinical and laboratory investigations. The cured rate of long-term drug therapy in this study was higher than that reported by most of other authors, 131I therapy was the best among the 3 modalites of therapy. The incidence of permanent hypothyroidism was fairly low in the thyroidectomy group. 97.3% of the patients with exophthalmos showed improvement after treatment in all the 3 groups.

Passive avoidance learning induced change in GAP43 phosphorylation in day-old chicks

Day-old chicks trained on a single trial passive discriminated avoidance task demonstrated a significant increase in in vitro phosphorylation of a 50 kDa protein in P2M fractions of total forebrain. The increase occurred 30 min posttraining, at a time when previous reports suggest that mechanisms for triggering protein synthesis-dependent long-term memory consolidation are activated. These changes in phosphorylation rates were accompanied by a substantial enhancement of total kinase activity. Immunoblotting studies with monoclonal anti-GAP43 antibody indicate that this protein is GAP43. These results contradict previous reports of a decrease in in vitro GAP43 phosphorylation following the same learning paradigm. A number of procedural differences may account for this discrepancy. The results suggest that changes in the phosphorylation state may be associated with mechanisms triggering long-term memory consolidation.

New triterpenoid saponins from Mussaenda pubescens

Three new triterpenoidal saponins, mussaendosides O [1], P [2], and Q [3] were isolated from whole plants of Mussaenda pubescens. These structures were elucidated on the basis of chemical and spectral methods, such as their 1H-1H COSY, HMQC, HMBC, TOCSY, and NOESY nmr spectra.

Comparative observation on effect of electric acupuncture of neiguan (P 6) at chen time versus xu time on left ventricular function in patients with coronary heart disease

Paired experimental design was adopted in this experiment for comparative observation on effect of electric acupuncture (EA) of Neiguan (P 6) at Chen Time (7 a.m. to 9 a.m.) versus Xu Time (7 p.m. to 9 p.m.) on left ventricular function in patients with coronary heart disease (CHD). The results show that EA performed at Chen Time could improve the left ventricular function of CHD patients as indicated by shortening of PEPI and decrease of PEPI/LVETI ratio; on the contrary, EA performed at Xu Time prolonged PEPI and raised PEPI/LVETI ratio in CHD patients, suggesting impairment of left ventricular function.

The T-cell repertoire contains cells reactive with hormones of the hypothalamic-pituitary-adrenal axis: recognition of synthetic peptide fragments of corticotropin-releasing hormone (CRH) and pro-opiomelanocortin (POMC) in the Lewis rat

This report characterizes T-cell lines developed against peptide fragments of the neuroendocrine hormones, corticotropin-releasing hormone (CRH) and pro-opiomelanocortin (POMC). A MHC Class II binding motif containing a serine (S) and glutamic acid (E) residue separated by five intervening amino acids was used as a template for synthesizing peptides that may serve as T-cell epitopes. T-cell lines were generated specifically against a 17-amino-acid peptide of POMC or CRH peptide. These T-cell lines were predominantly CD4+ T cells and proliferated in an antigen-specific fashion. Furthermore, proliferation of T-cell lines specific for peptide-hormones could be inhibited by anti-MHC Class II antibody. In vitro the whole CRH protein could be processed and recognized as antigenic by CRH peptide-specific T cells. In addition, POMC-specific T cells can recognize POMC peptide presented on the membrane of MHC Class II+ POMC T cells. These results indicate that the normal T-cell repertoire of the rat contains elements which can recognize and specifically proliferate to self-proteins of the hypothalamic-hypophyseal axis. Moreover, it seems that T lymphocytes themselves may present antigens which they synthesize. The relationship of these observations to autoimmune reactions affecting the hypothalamus and/or pituitary gland, or T-cell regulation, is the subject of ongoing investigation.

Myeloperoxidase gene expression in normal granulopoiesis and acute leukemias

Myeloperoxidase (MPO) is an abundant heme protein found in granulocytes and monocytes, which plays an important role in host defense against infection. MPO enzyme activity as determined by light microscopic cytochemistry has long been an important marker used in the diagnosis of acute leukemias and other hematopoietic disorders. Recently, MPO expression has been studied at the electron microscopic level, and monoclonal antibodies (mAbs) against MPO protein have been developed. Furthermore, techniques and probes for analysing MPO expression at the RNA level are now available. This has made possible more extensive studies of MPO expression in a wide range of neoplastic and preneoplastic blood disorders. This review will discuss the fundamental biology of MPO as well as recent developments in our understanding of MPO expression in leukemic cells and cell lines of various lineages.

[Anti-virus effect of aralosides]

The result showed that the anti-virus effect of aralosides on infections with poliovirus II, ECHO delta virus, adenovirus II, herpes simplex virus I, coxsackie B3 virus and coxsackie A16 virus was remarkable. Aralosides could inhibit the development of cytopathic effect (CPE) and protect cultural cells from being infected with the above viruses.

Insertional mutation of int protooncogenes in the mammary tumors of a new strain of mice derived from the wild in China: normal- and tumor-tissue-specific expression of int-3 transcripts

A new mouse strain, Mus musculus Jyg, has been isolated from the wild in China. After several generations of inbreeding, Jyg mice have been found to develop mammary adenocarcinomas at a high incidence (70-80%). In order to understand the mechanism by which mammary tumors are induced in these mice, we analyzed 23 available mammary tumors and liver tissues with regard to mouse mammary tumor virus (MMTV) proviral integrations and the pattern of int oncogene (Wnt-1, int-2/Fgf-3, and int-3) rearrangements and expression. We found that (1) Jyg mice do not carry endogenous MMTV; (2) all tumors showed multiple MMTV proviral integrations and expressed high levels of MMTV; (3) Jyg MMTV is distinguishable from other MMTV strains; (4) a high percentage of the tumors (70%) had insertional mutations in int loci (Wnt-1, 26%; int-2, 13%; and int3, 43%); and (5) unlike Wnt-1 and int-2, a 5.9-kb int-3-related transcript is expressed in developing mouse embryos of all stages and adult mouse tissues including mammary tumors, whereas a 2.4- to 3.6-kb transcript is expressed only in Jyg mammary tumors with int-3 mutations. Taken together, this newly developed mouse strain and the milk-borne MMTV that it carries constitute a novel system for studies of the host and viral specificity of insertional mutagenesis of multiple int protooncogenes by MMTV and the role of these genes in the pathogenesis of mouse mammary carcinomas and tumor cell heterogeneity.

Identification of an N-terminally acetylated encephalitogenic epitope in myelin proteolipid apoprotein for the Lewis rat

Proteolipid apoprotein (PLP) is a major component of the central nervous system myelin. As such, it is capable of inducing experimental allergic encephalomyelitis (EAE) in many subhuman species. On the basis of a putative MHC class II binding motif in Lewis rats (RT-1B1) recently identified in our laboratory, the present study identifies one pathogenic T cell epitope of PLP for the Lewis rat, located in the area between amino acid residues 217 and 240. Four overlapping synthetic peptides derived from this region were tested for their antigenicity and encephalitogenicity. Although the longer peptides could not induce EAE in the Lewis rats in their "theoretically" native form after immunization, they were endowed with encephalitogenic ability when modified by N-terminal acetylation. All animals immunized with N-acetylated peptides PLP 217-233 and PLP 224-240 developed inflammation in the lower spinal cord, but with very low incidence of clinical EAE (1 of 12). In contrast, none of the animals immunized with nonacetylated peptides developed either clinical or histologic EAE. Mild inflammation of the spinal cord was also found in two of four rats immunized with N-acetylated peptide PLP 220-234. The animals immunized with the decapeptide, N-acetylated PLP 224-233, did not develop inflammation of the spinal cord. Despite the low incidence of clinical disease, it was possible to generate vigorous T cell lines against all the peptides synthesized from this region of PLP.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of myocarditogenic peptides derived from cardiac myosin capable of inducing experimental allergic myocarditis in the Lewis rat. The utility of a class II binding motif in selecting self-reactive peptides

Cardiac myosin (CM) has been implicated as an autoantigen in the induction of experimental allergic myocarditis (EAM). At the present time no myocarditogenic peptides of CM have been identified. To identify CM peptides with myocarditogenic properties we have made use of a putative binding motif for the MHC class II molecule RT1.BI in the rat. The amino acid sequence of CM alpha-chain was scanned and found to contain nine peptides that contain this binding motif, three peptides found only in the cardiac form of myosin were chosen for further study. This manuscript describes the identification of two CM peptides capable of inducing EAM in the Lewis rat. In doing so this study demonstrates the utility of an MHC class II binding motif to (correctly) predict pathogenic, autoimmunity inducing, peptides. Peptides, CM 1, and CM 2 are the first peptides described that are capable of inducing EAM in rats. The utilization of CM 2 peptide has permitted the establishment of a long term, Ag specific cell line capable of adoptively transferring EAM. Moreover, the establishment of CM 2 specific T lymphocyte lines has permitted the description of a detailed proliferative response of a myocarditogenic cell line to a specific cardiac Ag. The identification of CM 1 and 2 formally proves that CM, and not a co-purified contaminant, is an Ag in EAM. Finally, this report documents that experimentally induced giant cell myocarditis is not a separate disease entity arising from a distinct cardiac Ag or CM epitope from regular myocarditis.

Identification of myocarditogenic peptides derived from cardiac myosin capable of inducing experimental allergic myocarditis in the Lewis rat. The utility of a class II binding motif in selecting self-reactive peptides

Cardiac myosin (CM) has been implicated as an autoantigen in the induction of experimental allergic myocarditis (EAM). At the present time no myocarditogenic peptides of CM have been identified. To identify CM peptides with myocarditogenic properties we have made use of a putative binding motif for the MHC class II molecule RT1.BI in the rat. The amino acid sequence of CM alpha-chain was scanned and found to contain nine peptides that contain this binding motif, three peptides found only in the cardiac form of myosin were chosen for further study. This manuscript describes the identification of two CM peptides capable of inducing EAM in the Lewis rat. In doing so this study demonstrates the utility of an MHC class II binding motif to (correctly) predict pathogenic, autoimmunity inducing, peptides. Peptides, CM 1, and CM 2 are the first peptides described that are capable of inducing EAM in rats. The utilization of CM 2 peptide has permitted the establishment of a long term, Ag specific cell line capable of adoptively transferring EAM. Moreover, the establishment of CM 2 specific T lymphocyte lines has permitted the description of a detailed proliferative response of a myocarditogenic cell line to a specific cardiac Ag. The identification of CM 1 and 2 formally proves that CM, and not a co-purified contaminant, is an Ag in EAM. Finally, this report documents that experimentally induced giant cell myocarditis is not a separate disease entity arising from a distinct cardiac Ag or CM epitope from regular myocarditis.

Identification of an N-terminally acetylated encephalitogenic epitope in myelin proteolipid apoprotein for the Lewis rat

Proteolipid apoprotein (PLP) is a major component of the central nervous system myelin. As such, it is capable of inducing experimental allergic encephalomyelitis (EAE) in many subhuman species. On the basis of a putative MHC class II binding motif in Lewis rats (RT-1B1) recently identified in our laboratory, the present study identifies one pathogenic T cell epitope of PLP for the Lewis rat, located in the area between amino acid residues 217 and 240. Four overlapping synthetic peptides derived from this region were tested for their antigenicity and encephalitogenicity. Although the longer peptides could not induce EAE in the Lewis rats in their "theoretically" native form after immunization, they were endowed with encephalitogenic ability when modified by N-terminal acetylation. All animals immunized with N-acetylated peptides PLP 217-233 and PLP 224-240 developed inflammation in the lower spinal cord, but with very low incidence of clinical EAE (1 of 12). In contrast, none of the animals immunized with nonacetylated peptides developed either clinical or histologic EAE. Mild inflammation of the spinal cord was also found in two of four rats immunized with N-acetylated peptide PLP 220-234. The animals immunized with the decapeptide, N-acetylated PLP 224-233, did not develop inflammation of the spinal cord. Despite the low incidence of clinical disease, it was possible to generate vigorous T cell lines against all the peptides synthesized from this region of PLP.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased expression of ICAM-1 during reoxygenation in brain endothelial cells

BACKGROUND AND PURPOSE

Thrombolysis is a promising therapy for acute ischemic stroke. However, there is evidence that neutrophils may physically plug cerebral microvessels on reperfusion, preventing the full benefit of thrombolysis. We undertook this study to determine whether there was increased endothelial expression of the intercellular adhesion molecule-1 (ICAM-1) gene during hypoxia-reoxygenation.

METHODS

We isolated and cultured human brain microvascular endothelial cells and subjected them to hypoxia (PO2 < 10 mm Hg) in an anaerobic chamber followed by variable periods of reoxygenation.

RESULTS

Twenty-hour periods of hypoxia did not lead to endothelial cytotoxicity as measured by a chromium-release assay. By Northern blot analysis, ICAM-1 mRNA transcripts were dramatically increased at 4 hours of reoxygenation but fell toward baseline (normoxia) by 12 and 24 hours. Hypoxia alone did not lead to an increase in mRNA levels. Western blot analysis showed an increased expression of ICAM-1 at 4, 12, and 24 hours of reoxygenation. The 4-hour increase in mRNA levels was not attenuated by pretreatment with 100 mumol/L allopurinol but was reduced by 30% with the addition of 20 mmol/L N-acetyl-L-cysteine at the time of reoxygenation and completely prevented by pretreatment with N-acetyl-L-cysteine.

CONCLUSIONS

Hypoxia-reoxygenation leads to an increase in ICAM mRNA levels that peaks at 4 hours in human brain microvascular endothelial cells. Pretreatment with N-acetyl-L-cysteine can completely block the increase in ICAM-1 mRNA levels.

Increased TGF-beta and decreased oncogene expression by omega-3 fatty acids in the spleen delays onset of autoimmune disease in B/W mice

This study was designed to investigate the mechanisms by which marine lipids rich in long chain omega-3 fatty acids inhibit autoimmune disease and prolong the survival rate in female (NZB/NZW) F1 (B/W) mice, an animal model for human SLE. Nutritionally adequate semipurified diets containing at 10% either corn oil (CO) or fish oil (FO) were fed from 1 mo of age and were monitored for proteinuria and survival. Proteinuria was detected earlier and became progressively severe in CO-fed mice. The average life span was significantly shortened by the CO diet (266.7 days +/- 12.5), whereas FO extended the survival significantly (402.1 days +/- 26.1; p < 0.001). A cross-sectional study at 6.5 mo of age revealed an increased proliferative response to T cell mitogens including bacterial superantigens and decreased serum anti-dsDNA Ab titers in the FO group compared with the CO group. Furthermore, splenocytes from the FO group when stimulated with Con A had higher IL-2 and lower IL-4 production similar to that of young (3.5 mo) mice. Flow cytometric analyses of splenocytes revealed lower Ig+, higher lymphocyte endothelial cell adhesion molecule-1, and lower Pgp-1+ cells within CD4+ and CD8+ subsets in FO-fed mice. Also, elevated IL-2 and IL-4 and significantly higher TGF-beta 1 and lower c-myc and c-ras mRNA expression and higher TGF-beta 1 and significantly lower c-Myc and c-Ha-Ras proteins were detected in spleens of FO-fed mice. Fatty acid analysis revealed significantly higher linoleic (18:2 omega-6) and arachidonic (20:4 omega-6) acid levels in splenocytes of the CO-fed group and higher eicosapentaenoic (20:5 omega-3) and docosahexanoic (22:6 omega-3) acid levels in the FO-fed group, indicating that changes in membrane fatty acid composition may contribute to the altered immune function and gene expression during the development of murine SLE.

Increased TGF-beta and decreased oncogene expression by omega-3 fatty acids in the spleen delays onset of autoimmune disease in B/W mice

This study was designed to investigate the mechanisms by which marine lipids rich in long chain omega-3 fatty acids inhibit autoimmune disease and prolong the survival rate in female (NZB/NZW) F1 (B/W) mice, an animal model for human SLE. Nutritionally adequate semipurified diets containing at 10% either corn oil (CO) or fish oil (FO) were fed from 1 mo of age and were monitored for proteinuria and survival. Proteinuria was detected earlier and became progressively severe in CO-fed mice. The average life span was significantly shortened by the CO diet (266.7 days +/- 12.5), whereas FO extended the survival significantly (402.1 days +/- 26.1; p &lt; 0.001). A cross-sectional study at 6.5 mo of age revealed an increased proliferative response to T cell mitogens including bacterial superantigens and decreased serum anti-dsDNA Ab titers in the FO group compared with the CO group. Furthermore, splenocytes from the FO group when stimulated with Con A had higher IL-2 and lower IL-4 production similar to that of young (3.5 mo) mice. Flow cytometric analyses of splenocytes revealed lower Ig+, higher lymphocyte endothelial cell adhesion molecule-1, and lower Pgp-1+ cells within CD4+ and CD8+ subsets in FO-fed mice. Also, elevated IL-2 and IL-4 and significantly higher TGF-beta 1 and lower c-myc and c-ras mRNA expression and higher TGF-beta 1 and significantly lower c-Myc and c-Ha-Ras proteins were detected in spleens of FO-fed mice. Fatty acid analysis revealed significantly higher linoleic (18:2 omega-6) and arachidonic (20:4 omega-6) acid levels in splenocytes of the CO-fed group and higher eicosapentaenoic (20:5 omega-3) and docosahexanoic (22:6 omega-3) acid levels in the FO-fed group, indicating that changes in membrane fatty acid composition may contribute to the altered immune function and gene expression during the development of murine SLE.

[The relationship between the amount of gingival crevicular fluid and periodontitis]

In this paper, we report the results of comparing the amount of GCF, collected from 100 patients suffering from periodontitis and 40 patients suffering from gingivitis with 64 normal control subjects. The results showed that the amount of GCF is independent of sex and where the GCF was collected, ie., either side of the maxillary or mandibular teeth. However, the fluid amount was closely related to inflammation of the periodontium and significantly related to the severity of inflammation and bone destruction. This study provide evidence that the determination of the GCF amount is an essential criteria for detecting periodontal activity.

Dietary regulation of mammary tumorigenesis in RIII/Sa mice: investigation of a possible mechanism

The effects of caloric restriction on the incidence of mammary tumor development, the levels of the expression of mouse mammary tumor virus (MMTV)- and prolactin-RNA, as well as the levels of serum prolactin, were investigated in virgin RIII/Sa mice, a strain known to display a high incidence of spontaneous mammary tumor development. Of the 54 mice fed a low-calorie (LC; 10 kcal/day) diet containing low fat (LF; 5% corn oil) for a period of 72 weeks, only seven mice were found to develop mammary tumors, an incidence of 13%. By contrast, the cumulative tumor incidence in a similar sized group of mice, fed a high-calorie (HC; 16 kcal/day) low fat-containing diet was 73%. Estimation of the relative levels of MMTV-RNA, as determined by Northern and slot blot hybridizations, in the mammary glands of mice fed LCLF and HCLF diets for 8, 10, 16, 28, and 36 weeks revealed that the LCLF diet-fed mice expressed 4-15-fold less RNA than the HCLF diet-fed mice. Interestingly, however, the LCLF diet did not appear to exert any effect on the expression of prolactin RNA even though it reduced the levels of serum prolactin. We suggest that in RII/Sa mice the modulation of MMTV-induced mammary tumors by dietary calorie is linked to the secretion of serum prolactin which, in turn, affects the replication of MMTV required for mammary cell transformation.

Bronchial smooth muscle energetics: effect of iodoacetate and hypoxia

The active pressure (AP) and the oxygen consumption (VO2) of segments of bovine bronchi were measured during a 10 microM carbachol stimulation. VO2 did not increase during the carbachol-induced contraction whereas there was a twofold increase in the lactate production. Addition of the glycolytic blocker, iodoacetate (83 microM), decreased the AP to 68.9 +/- 6.4% of control value (n = 10, P < 0.05) whereas VO2 remained constant. The lactate concentration in the physiological solution decreased significantly (P < 0.05). When the solution was supplemented with pyruvate (10 mM), the effect of iodoacetate was antagonized. Under hypoxic condition, i.e. when the solution was bubbled with 5% CO2 in N2, VO2 decreased sharply to 7.7 +/- 3.1% of control (n = 8, P < 0.05) whereas AP did not change. The combined effect of iodoacetate and hypoxia led to a fall in both AP (12.4 +/- 3.0% of control, n = 7, P < 0.05) and VO2 (21.2 +/- 5.1%, P < 0.05). These results suggest that the energy required by bronchial smooth muscle to generate contraction could be supplied by either the aerobic or the anaerobic pathway.

Prostaglandin E2 level in gingival crevicular fluid and its relation to the periodontal pocket depth in patients with periodontitis

Prostaglandin E2 (PGE2) levels in gingival crevicular fluid (GCF) of 46 normal controls and 90 patients suffering from periodontitis with different periodontal pocket depths were measured by radioimmunoassay (RIA). The results demonstrated that PGE2 levels in the GCF of the periodontal pockets are higher in patients with periodontitis. The PGE2 level rises as the periodontal pocket deepens, especially in cases where the periodontal pocket depth exceeds 6 mm. This study shows that the PGE2 level is significantly related to the severity of bone destruction in periodontitis.

ICAM-1 expression on human brain microvascular endothelial cells

There is evidence that leukocytes play an important role in mediating tissue injury during acute ischemic stroke. Endothelial cell adhesive molecules such as ICAM-1 are required for the migration of leukocytes into the brain. Using an Elisa, we compared the expression of ICAM-1 by human brain microvascular endothelial cells with human umbilical vein endothelial cells. There was constitutive surface expression of ICAM-1 on both brain and umbilical vein endothelial cells. With cytokine (IL-1 beta or TNF) or lipopolysaccaride stimulation, ICAM-1 surface expression increased to a greater extent on brain than on umbilical vein endothelial cells. Dexamethasone at doses up to 100 microM had no effect on inhibiting cytokine-mediated upregulation of ICAM-1 on human brain microvascular endothelial cells.

The amino acid sequence of iguana (Iguana iguana) pancreatic ribonuclease

The pyrimidine-specific ribonuclease superfamily constitutes a group of homologous proteins so far found only in higher vertebrates. Four separate families are found in mammals, which have resulted from gene duplications in mammalian ancestors. To learn more about the evolutionary history of this superfamily, the primary structure and other characteristics of the pancreatic enzyme from iguana (Iguana iguana), a herbivorous lizard species belonging to the reptiles, have been determined. The polypeptide chain consists of 119 amino acid residues. The positions of insertions and deletions in the sequence are identical to those in the enzyme from snapping turtle. However, the two enzymes differ at 54% of the amino acid positions. Iguana ribonuclease contains no carbohydrate, although the enzyme possesses three recognition sites for carbohydrate attachment, and has a high number of acidic residues in a localized part of the sequence.