[Histological change of keratinocyte in full-thickness skin autograft and its effect on hyperpigmentation of the graft]

To understand the reason of hyperpigmentation following full-thickness skin autograft, 54 guinea pigs were selected as skin autograft models. The changes of density of epidermal keratinocyte (KC) and the amount and distribution of melanin in the epidermal KC were observed by histological, histochemical and autoradiographic techniques. The results showed: (1) The histological changes of KC were in fact a wound-repair process; (2) The increased melanin in KC coordinated with "multi-overlapping screen" effect, a result of multiple layers of "supranuclear cap", was the direct cause of hyperpigmentation of the graft and (3) The hydrolytic disturbance of melanin in KC and the longer life span of the KC were probably the important reasons for the increase of melanin in the epidermis.

Identification of an insulin-responsive element in the rat insulin-like growth factor-binding protein-3 gene

The hepatic expression and serum levels of insulin-like growth factor-binding protein-3 (IGFBP-3) are decreased in insulin-dependent and insulin-resistant diabetes. Insulin increases hepatic IGFBP-3 expression by enhancing gene transcription. This report identifies sequences within the IGFBP-3 promoter that are necessary and sufficient for the response to insulin in hepatic nonparenchymal cells. By transient transfection, we mapped the insulin response element to the -1150 to -1124 base pair (bp) region of the rat IGFBP-3 promoter. Three tandem repeats of the -1150 to -1117 bp region conferred insulin responses in a heterologous promoter. Gel shift analyses revealed a 3-fold increase in DNA-protein complex formation with nuclear extracts obtained from insulin-stimulated nonparenchymal cells compared with cells incubated without insulin and revealed 3-4-fold decrease in complex formation with nuclear extracts obtained from the livers of streptozotocin-diabetic rats compared with control rats. Mutational analysis of this 34-bp region showed a core sequence of 10 bp (-1148 to -1139) that is critical for interaction with insulin-induced trans-acting factors. Southwestern blotting revealed a approximately 90-kDa protein that was increased 2-3-fold by the addition of insulin. Thus, we have identified cis-acting DNA sequences that are responsible for regulation of IGFBP-3 transcription by insulin and essential for binding of insulin-responsive nuclear factors.

[An image analysis of the morphological changes of LH cells during LH release peak induced by LHRH in male rats]

The relationship between the peak of LH release induced by exogenous LHRH and morphological change of LH cells in male rats was investigated by ABC Affinity histochemistry and qualitatively characterized by Medical Image Processing System-I. The serum LH concentration was determined by RIA. During the period of basal secretion of LH (3.76 +/- 0.39 ng/ml), the LH cells might be assigned at a storage state. Most of such cells (56.7%) are round and large, and their cross sectional areas are larger then 340 micron 2, usually containing large vacuoles, while the smaller cells of X-sectional area less then 190 micron 2 counted only 2% of the total population. Thirty minutes after injection of LHRH the serum LH level increased significantly (6.46 +/- 1.6 ng/ml, P < 0.01), there appeared a lot of small angular cells, the average cross sectional areas of LH cells decreased significantly (P < 0.0001). When LHRH was injected at sixty minutes, the LH level reached a peak (18.78 +/- 0.79 ng/ml), the number of the large cells decreased to only 4%, while the small cells increased to 66%, vacuoles were almost disapperanced and a large part of cells (52.6%) became irregular. Thereafter, the LH serum gradually subsided to its original basal level with attendant resumption of the morphology of the LH cells at storage state. It appears that the morphological changes, such as size, shape, vacuoles and so on, of the LH cells may serve as an important index for showing the effect of LHRH on LH secretion.

Hyperthermia enhances spectrin breakdown in transient focal cerebral ischemia

Calpain-mediated spectrin degradation is triggered by cerebral ischemia and, when persistent, is thought to signal irreversible neuronal injury. Hyperthermia superimposed upon cerebral ischemia may exacerbate the injury process. In this study, we compared the extent of spectrin degradation in the brains of rats subjected to 1 h of transient proximal middle cerebral artery (MCA) clip-occlusion performed under conditions of cranial normothermia (37 degrees C) or mild cranial hyperthermia (39 degrees C). Immunocytochemical localization of spectrin breakdown products was achieved by the use of a rabbit polyclonal antibody which reacted selectively with calpain-generated fragments of brain spectrin. The perfusion times studied were 1, 4 or 24 h. Following normothermic MCA occlusion, spectrin immunoreactivity was present only occasionally and only in scattered cortical neurons immediately upon reperfusion and 1 h later; all normothermic brains showed space immunoreactivity at 4 h of reperfusion; and no immunoreactivity was detected at 24 h. By contrast, following hyperthermic MCA occlusion, moderate-to-intense immunostaining was present in cortical pyramidal neurons even immediately upon reperfusion and persisted at 1 h of reperfusion. At 4 and 24 h, most brains exhibited dense immunoreactivity associated with morphologically shrunken neurons. Following 24 h survival, semi-thick plastic sections revealed intact neuropil and only selective neuronal necrosis in normothermic rats. By contrast, pan-necrosis was evident 24 h after the hyperthermic ischemic insult. These results indicate that mild cranial hyperthermia superimposed upon transient focal ischemia markedly enhances calpain activation and spectrin degradation; this process appears to be an important mechanism by which hyperthermia exacerbates ischemic injury.

Different administration schedules of the same dose of 2,5-hexanedione influence the development of neuropathy and the toxicokinetics

The same total dose (1.2 g/kg/week) of 2,5-hexanedione (2,5-HD) was administered subcutaneously at 100 mg/kg/12 hr, 200 mg/kg/24 hr, and 400 mg/kg/48 hr to three groups of Donryu rats. The peripheral neuropathy induced by 2,5-HD was confirmed by clinical observation every day, and neurophysiological measurements every 4 weeks. During the 15th week of this experiment, 2,5-HD concentrations in plasma 0.5 to 24 hours after injection were determined. It was found that the greater the dose of 2,5-HD per treatment injected, the earlier peripheral neuropathy developed. Toxicokinetic analysis showed that both the values of the area under the plasma concentration versus time curve and the half life of 2,5-HD were increased, but the excretion parameters (Ke) were decreased, in animals treated with 200 mg/kg/24 hr and 400 mg/kg/48 hr 2,5-HD.

Bilateral ischemic tolerance of rat hippocampus induced by prior unilateral transient focal ischemia: relationship to c-fos mRNA expression

The purpose of this study was to determine whether transient unilateral (2 h) middle cerebral artery occlusion (MCAo) is capable of inducing bilateral ischemic tolerance in hippocampal CA1 neurons when temporary bilateral forebrain ischemia by two-vessel occlusion (2VO) is carried out 3 days later, and to explore the relationship of this tolerance to the regional expression of c-fos and hsp-70 mRNA. Rats were sacrificed 4 days after 2VO, and normal-appearing neurons in CA1 subregions were counted. Rats subjected to MCAo and 2VO showed significant protection of CA1 neurons in both hippocampi, whereas rats which underwent sham MCAo and 2VO typically had severe bilateral destruction of CA1 neurons (normal neuron counts, ipsilateral medial CA1: 59.8 +/- 7.2 vs 16.6 +/- 7.8 (mean +/- s.e.m.); middle CA1: 50.0 +/- 4.7 vs 16.0 +/- 8.8; lateral CA1: 43.5 +/- 5.7 vs 13.8 +/- 6.3; contralateral, medial CA1: 52.3 +/- 6.3 vs 17.0 +/- 6.4; middle CA1: 43.3 +/- 4.7 vs 19.8 +/- 8.1; lateral CA1: 45.5 +/- 4.6 vs 26.0 +/- 10.3, respectively). This neuronal tolerance was preceded by the early bilateral induction of c-fos mRNA, which may in turn lead to expression of critical target genes that promote cell recovery.

A site of interaction between pleckstrin's PH domains and G beta gamma

Pleckstrin is a 40 kDa substrate for protein kinase C found in platelets and neutrophils. Based upon its sequence, pleckstrin contains two of the recently-described PH domains that are thought to be binding motifs for phosphatidyl 4,5-bisphosphate (PIP2) and/or G protein beta gamma heterodimers (G beta gamma). In the present studies we have examined the interaction between pleckstrin and G beta gamma by incubating pleckstrin fusion proteins with lysates from human platelets. In this analysis, both the N-terminal and C-terminal PH domains from pleckstrin bound G beta gamma in vitro, as did peptides containing as little as the first 30 residues of the C-terminal pleckstrin PH domain. Introduction of a point mutation into this region, analogous to the mutation in the Btk PH domain that causes X-linked immunodeficiency disease (XID) in mice, dramatically disrupted this interaction. We propose that pleckstrin may interact with G beta gamma, and that one potential site for this interaction involves the first 30 residues of pleckstrin's C-terminal PH domain.

INDEPTH Wide-Angle Reflection Observation of P-Wave-to-S-Wave Conversion from Crustal Bright Spots in Tibet

Three-component wide-angle seismic data acquired in southern Tibet during Project INDEPTH show strong P-to-S converted reflections from reflectors that are aligned at a depth of approximately 15 kilometers beneath the northern Yadong-Gulu rift. These converted reflections are locally higher in amplitude than the corresponding P-wave reflections. Modeling of reflection mode conversion as a function of incidence angle indicates that this condition obtains for a reflector that is a solid over fluid interface; it is not typical of a solid-solid interface. The likely candidates for a fluid trapped within the crystalline crust of southern Tibet are granitic magma and water (brine).

Evidence from Earthquake Data for a Partially Molten Crustal Layer in Southern Tibet

Earthquake data collected by the INDEPTH-II Passive-Source Experiment show that there is a substantial south to north variation in the velocity structure of the crust beneath southern Tibet. North of the Zangbo suture, beneath the southern Lhasa block, a midcrustal low-velocity zone is revealed by inversion of receiver functions, Rayleigh-wave phase velocities, and modeling of the radial component of teleseismic P-waveforms. Conversely, to the south beneath the Tethyan Himalaya, no low-velocity zone was observed. The presence of the midcrustal low-velocity zone in the north implies that a partially molten layer is in the middle crust beneath the northern Yadong-Gulu rift and possibly much of southern Tibet.

Bright Spots, Structure, and Magmatism in Southern Tibet from INDEPTH Seismic Reflection Profiling

INDEPTH seismic reflection profiling shows that the decollement beneath which Indian lithosphere underthrusts the Himalaya extends at least 225 kilometers north of the Himalayan deformation front to a depth of approximately 50 kilometers. Prominent reflections appear at depths of 15 to 18 kilometers near where the decollement reflector apparently terminates. These reflections extend north of the Zangbo suture to the Damxung graben of the Tibet Plateau. Some of these reflections have locally anomalous amplitudes (bright spots) and coincident negative polarities implying that they are produced by fluids in the crust. The presence of geothermal activity and high heat flow in the regions of these reflections and the tectonic setting suggest that the bright spots mark granitic magmas derived by partial melting of the tectonically thickened crust.

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.

Quantitative evaluation of blood-brain barrier permeability following middle cerebral artery occlusion in rats

A sensitive quantitative fluorescence method was used to explore the time course and regional pattern of blood-brain barrier (BBB) opening after transient middle cerebral artery occlusion (MCAo). Male Sprague-Dawley rats were anesthetized with halothane and subjected to 2 h of temporary MCAo by retrograde insertion of an intraluminal nylon suture, coated with poly-L-lysine, through the external carotid artery into the internal carotid artery and MCA. Damage to the BBB was judged by extravasation of Evans Blue (EB) dye, which was administered either 2, 3, 24 or 48 h after onset of MCAo. Fluorometric quantitation of EB was performed 1 or 2 h later in six brain regions. Cerebral infarction volumes were quantitated from histopathological material at 72 h. EB extravasation first became grossly visible in the ipsilateral caudoputamen and neocortex following 3 h of MCAo, was grossly unapparent at 24-26 h, and was maximal at 48-50 h. Fluorescence quantitation confirmed that BBB opening was absent at 2-3 h but present at all later times. In the hemisphere ipsilateral to MCAo, a 179% mean increase in extravasation of EB (compared to sham rats) was measured at 4 h, 407% at 5 h, 311% at 26 h and 264% at 50 h. (in each case, P < 0.05 vs. sham). The volume of infarcted tissue at 72 h in this model was 163.6 +/- 7.7 mm3. Our results indicate that an initial, acute disruption of the BBB occurs between 3 and 5 h following MCAo, and that a later, more widespread increase in regional BBB permeability is present at 48 h. Regional measurement of Evans Blue extravasation offers a precise means of quantitating BBB disruption in focal cerebral ischemia; this method will be of considerable utility in assessing the BBB-protective properties of pharmacological agents.

Phosphopleckstrin inhibits gbetagamma-activable platelet phosphatidylinositol-4,5-bisphosphate 3-kinase

Pleckstrin, the prototypic protein containing two copies of the pleckstrin homology domain, is a prominent substrate of protein kinase C in platelets and neutrophils. Both cell types have p85 subunit-containing phosphoinositide 3-kinase (p85/PI3K) and non-p85-containing PI3K (PI3Kgamma) that is activated by betagamma subunits of heterotrimeric GTP-binding proteins. We have shown that a PI3K product, phosphatidylinositol (PI) 3,4,5-trisphosphate, promotes pleckstrin phosphorylation in platelets. Since pleckstrin homology domains are thought to interact with Gbetagamma heterodimers and/or PI(4,5)P2, we have examined the effects of recombinant pleckstrins on platelet PI3Kgamma and p85/PI3K activities. Depending upon its phosphorylation/charged state, pleckstrin inhibits PI3Kgamma, but not p85/PI3K. Pleckstrin-mediated inhibition of PI3Kgamma is overcome by excess Gbetagamma and is restricted to PI(4,5)P2 as substrate, i.e. pleckstrin does not inhibit phosphorylation of PI()P or PI. Consistent with this, activation of protein kinase C by exposure of platelets to beta-phorbol diester (to increase endogenous pleckstrin phosphorylation) prior to platelet lysis causes inhibition of Gbetagamma-stimulatable PI3K activity only with respect to PI(4,5)P2 substrate. This phosphopleckstrin-mediated inhibition is overcome by increasing concentrations of Gbetagamma. We propose that phosphorylation of pleckstrin may constitute an important inhibitory mechanism for PI3Kgamma-mediated cell signaling.

Anti-CD40 ligand antibody treatment prevents the development of lupus-like nephritis in a subset of New Zealand black x New Zealand white mice. Response correlates with the absence of an anti-antibody response

Systemic lupus erythematosus is characterized by B cell production of pathogenic autoantibodies dependent upon cooperation from CD4+ Th cells. The interaction between CD40 on B cells and CD40 ligand (CD40L) on Th cells is necessary for normal thymus-dependent Ab production. An anti-murine CD40L mAb blocks binding of CD40L to CD40 and prevents primary and secondary immune responses to thymus-dependent Ags. In this study, New Zealand Black x New Zealand White lupus-prone mice treated with this anti-CD40L Ab from ages 4 to 10 mo had reduced anti-DNA autoantibody production and renal disease and significantly prolonged survival compared with control mice. Pathologic examination verified the absence of significant renal damage or immune deposition in responding mice. Mice that responded to treatment did not develop an Ab response to the administered Ab. Long-term survivors mounted a substantial Ab response to keyhole limpet hemocyanin after completion of anti-CD40L Ab treatment, suggesting that some of the immunosuppressive effects of the Ab may be reversible. These results suggest a human form of this Ab may have therapeutic utility in human systemic lupus erythematosus.

Anti-CD40 ligand antibody treatment prevents the development of lupus-like nephritis in a subset of New Zealand black x New Zealand white mice. Response correlates with the absence of an anti-antibody response

Systemic lupus erythematosus is characterized by B cell production of pathogenic autoantibodies dependent upon cooperation from CD4+ Th cells. The interaction between CD40 on B cells and CD40 ligand (CD40L) on Th cells is necessary for normal thymus-dependent Ab production. An anti-murine CD40L mAb blocks binding of CD40L to CD40 and prevents primary and secondary immune responses to thymus-dependent Ags. In this study, New Zealand Black x New Zealand White lupus-prone mice treated with this anti-CD40L Ab from ages 4 to 10 mo had reduced anti-DNA autoantibody production and renal disease and significantly prolonged survival compared with control mice. Pathologic examination verified the absence of significant renal damage or immune deposition in responding mice. Mice that responded to treatment did not develop an Ab response to the administered Ab. Long-term survivors mounted a substantial Ab response to keyhole limpet hemocyanin after completion of anti-CD40L Ab treatment, suggesting that some of the immunosuppressive effects of the Ab may be reversible. These results suggest a human form of this Ab may have therapeutic utility in human systemic lupus erythematosus.

Computer-assisted image-averaging strategies for the topographic analysis of in situ hybridization autoradiographs

We report the application of a computer-based image-averaging strategy to the quantitative topographic analysis of in situ hybridization autoradiographs, based upon a disparity-analysis algorithm. We illustrate this approach for a representative antisense riboprobe-the astrocytic marker, glial fibrillary acid protein (GFAP)-in the setting of fluid-percussion brain injury in rats. Sequential coronal autoradiographs in individual animals are first digitized and aligned by disparity analysis. Next, coronal sections of all brains of a given experimental group are placed in register with one another, using a common anatomic reference level. One brain of the series serves as a template, and corresponding sections of other brains are mapped into its contour at each level. In this manner, average and standard deviation image data sets may be generated. With thresholding techniques, individual data sets can be dichotomized with respect to a chosen threshold, and frequency maps can be generated at each coronal level, displaying numbers of brains showing supra-threshold levels of mRNA at each pixel location. Pixel-by-pixel statistical comparison of data sets obtained under two different conditions (e.g., 30 min vs. 24 h following brain trauma) is then feasible. A digitized functional-anatomic brain atlas may be fitted to the images to assist analysis. Computer-based image analysis of in situ hybridization autoradiographs greatly extends the utility and applicability of this technique.

Middle cerebral artery occlusion in the rat by intraluminal suture. Neurological and pathological evaluation of an improved model

BACKGROUND AND PURPOSE

The purpose of the present study was to evaluate a modified method of intraluminal suture occlusion of the middle cerebral artery (MCA) on the volume of brain infarction and on neurobehavioral function in rats subjected to a temporary focal ischemic insult.

METHODS

Male Sprague-Dawley rats were anesthetized with halothane and subjected to 60 minutes or 2 hours of temporary MCA occlusion (MCAo) by an intraluminal thread. In one group of rats, the suture was coated with poly-L-lysine, while in a second group, a conventional uncoated suture was used. Behavioral function was evaluated at 50 to 60 minutes after occlusion and during a 3-day period after MCAo. Three days after MCAo brains were perfusion-fixed and infarct volumes were measured.

RESULTS

In rats with 60-minute MCAo, only 3 of 7 animals with uncoated sutures had infarcts, whereas in the group with poly-L-lysine-coated sutures, all rats (n = 7) exhibited infarction (P = .009, Fisher's exact test). With 2 hours of MCAo, total infarct volume (corrected for brain edema) was significantly larger in rats with poly-L-lysine-coated sutures than in the group with uncoated sutures (mean +/- SEM, 122.1 +/- 4.8 versus 67.0 +/- 18.2 mm3, respectively; P = .03; n = 4 in each group). In the 2-hour MCAo study, infarct volumes in the uncoated-suture group tended to be variable and inconsistent (coefficient of variation, 54%) compared with the group in which sutures were coated with poly-L-lysine, in which a highly consistent infarct was produced (coefficient of variation of infarct volume, 8%).

CONCLUSIONS

Reversible MCAo in which a poly-L-lysine-coated intraluminal suture was used proved to be a reliable and effective modification of this technique, yielding consistently larger infarcts and greatly reduced interanimal variability.

3,4-Dichloropropionanilide-induced atrophy of the thymus: mechanisms of toxicity and recovery

The herbicide 3,4-dichloropropionanilide (propanil) has several well-documented neurotoxic and immunotoxic effects on mice. We report here a detailed characterization of the effects of propanil exposure on the thymus. We found that at doses of 100-200 mg/kg, propanil induces significant thymic atrophy between 2 and 7 days postexposure. This atrophy is characterized by a decrease in thymus/body ratio and a decrease in cellularity. Flow cytometric analyses of thymuses from propanil- and vehicle-treated mice indicate that the CD4(+) CD8(+) population of immature cells, is most significantly decreased in propanil-exposed mice. We performed cell cycle analysis of thymocyte populations using two-color surface staining and the DNA binding dye 7-aminoactinomycin D to determine whether thymic atrophy was associated with changes in the percentages of cells in the S, G2, and M phases of the cell cycle. We found a high percentage of proliferating CD4(+)CD8(+) thymocytes 4 days after exposure. Thus, recovery of the thymus occurs following increases in thymocyte proliferation, most notably the immature CD4(+) CD8(+) thymocytes. We tested the hypothesis that glucocorticoids play a role in the observed atrophy by examining thymuses in adrenalectomized, propanil-treated mice. No atrophy was observed in those animals. These results suggest that propanil has an immunotoxic effect on the thymus that appears to be mediated, in part, by endogenous glucocorticoids.

[Factors influencing long-term survival in patients with nonoperable lung cancer: an analysis by Cox model]

This paper reports a prospective survey of 173 patients with nonoperable lung cancer between January. 1, 1983 to March. 1, 1985. The follow-up rate was 97.7% over five years. Fourteen factors including sex, age, course of disease before treatment, clinical stage, performance status, size of mass, metastatic status, hemoglobin before treatment, short-term response to treatment and so on which might influence long term survival were studied by univariate analysis (Kruskal-Wallis test for Kaplan-Meier survival curve) and by multivariate analysis (Cox's proportional hazad model and audio-visual chart test for goodness of fit). Multivariate analysis using Cox's model revealed 6 significant prognostic factors: performance status, short-term response to treatment, clinical stage, hemoglobin before treatment, smoking index and method of treatment. The survival prediction equation was chi 2 = 72.14, nu = 6, P < 0.0001. The results indicate that the performance status and the CR rate of the initial treatment, among other things, is the major factors affecting prognosis.

Atypical cytochrome P450 induction profiles in glomerular mesangial cells at the mRNA and enzyme level. Evidence for CYP1A1 and CYP1B1 expression and their involvement in benzo[a]pyrene metabolism

Recent studies in this laboratory have shown that benzo[a]pyrene (BaP) modulates growth factor-related gene expression and proliferation of renal glomerular mesangial cells (GMCs) in vitro. Because many of the toxic and biochemical effects of this polycyclic aromatic hydrocarbon are mediated through oxidative metabolism, the present studies were conducted to examine the patterns of cytochrome P450IA1 (CYP1A1) and P4501B1 (CYP1B1) inducibility in mesangial cells and the molecular consequences of this response. Exposure of cultured GMCs to BaP (30 microM) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 10 nM) for 24 hr induced CYP1A1 mRNA levels, a response abolished by cotreatment with 10 microM cycloheximide. The pattern of hydrocarbon inducibility was atypical in that BaP was a more effective inducer of CYP1A1 gene expression than TCDD, and both hydrocarbons induced aryl hydrocarbon hydroxylase (AHH) activity, but not ethoxyresorufin-O-deethylase activity. Cotreatment with alpha-naphthoflavone (alpha NF, 1 microM) or ellipticine (ELLIP, 0.1 nM) only partially inhibited the induction of AHH activity by BaP (30 microM). BaP and TCDD also induced expression of the CYP1B1 protein and the pattern of induction was comparable to that observed for CYP1A1. Treatment of GMCs with 30 microM BaP was associated with the formation of eight DNA adducts, and their occurrence could be inhibited by pretreatment with alpha NF (1 microM), but not ELLIP (0.1 nM). These results demonstrate that CYP1A1 and CYP1B1-related activities are induced in GMCs by BaP and TCDD and this induction is associated with metabolism of BaP to reactive intermediates that bind covalently to DNA.

Cyclosporin A, an inhibitor of calcineurin, impairs memory formation in day-old chicks

Considerable evidence exists that changes in the phosphorylation state of neuronal proteins are correlated with learning and that inhibition of various protein kinases disrupts memory formation. Given the reversible nature of protein phosphorylation, a role for protein phosphatases in memory processing also seems likely. It has been shown recently that administration of the phosphatase inhibitor, okadaic acid, disrupts memory formation in day-old chicks, with retention deficits first appearing at approximately 40 min post-training [93]. In the present study the intracranial administration of the immunosuppressant cyclosporin A was also found to produce retention deficits in day-old chicks trained on a single-trial, passive-avoidance task, but the deficits were not significant until 85 min post-training. The difference could not be attributed to differences in the pharmacokinetics of the drugs. Since okadaic acid preferentially inhibits protein phosphatases 1 and 2A, while cyclosporin A is reported to inhibit only the Ca2+/calmodulin-dependent protein phosphatase, calcineurin, it is possible that different phosphatases may be involved in distinct stages of memory formation, as has been reported previously for protein kinases. The possibility that cyclosporin A may, in addition, act through inhibition of cyclophilin's peptidyl-prolyl-cis/transisomerase activity is also canvassed.

Neuroprotective effects of hypothermia and U-78517F in cerebral ischemia are due to reducing oxygen-based free radicals: an electron paramagnetic resonance study with gerbils

Free radicals are implicated as causative agents in various forms of tissue destruction. Considerable circumstantial evidence suggests that oxygen-based free radicals generated as blood flow returns to formerly ischemic brain areas are mainly responsible for the neurodegeneration that follows periods of cerebral ischemia. In general, oxygen-based free radicals are highly reactive and exist for only a brief period of time. This makes the direct measurement of many of these free radicals rather difficult. Much of the current knowledge of free radicals in cerebral ischemia is based on observations of chemical changes brought about by the free radicals rather than on direct observations of the free radicals themselves. Low temperature electron paramagnetic resonance spectroscopy is one method that allows the direct study of free radicals. Compared to samples from sham-operated controls, samples of hippocampus taken from gerbils exposed to 15 min of forebrain ischemia followed by 15 min of reperfusion, frozen in liquid nitrogen less than 20 sec after sacrifice, and scanned by low temperature (100 K) electron paramagnetic resonance, show a significant increase in oxygen-based free radicals and a decrease in carbon-based ubiquinone-like free radicals. The ischemia-induced increase in oxygen-based free radicals is prevented by the intraperitoneal injection of the antioxidant drug U-78517F at the start of reperfusion and by hypothermia. However, neither intervention alters the ischemia-induced reduction in the ubiquinone-like free radicals. This suggests that the neuroprotective actions of hypothermia and U-78517F include a direct reduction in the oxygen-based free radical burden of the post-ischemic tissue.

Saponins from Mussaenda pubescens

Two new triterpenoid saponins, named mussaendosides G and K, were isolated from aerial parts of Mussaenda pubescens by normal and reverse phase chromatography. On the basis of chemical and spectroscopic methods, their structures have been elucidated as heinsiagenin A 3-O-{alpha-L-rhamnopyranosyl(1-->2)-[beta-D-glucopyranosyl (1-->6)]-beta-D-glucopyranosyl(1-->2)}-alpha-L -rhamnopyranosyl(1-->4)-O-beta-D-glucopyranoside and 3 beta,19 alpha-dihydroxyl-olean-12-en-24, 28-dioic acid-24,28-di-O-beta-D-glucopyranoside, respectively.

Hypericin-induced phototoxicity in cultured fibroblasts and swine erythrocytes

Hypericin is a naturally occurring photosensitizer, whose presence in plants has been responsible for cutaneous phototoxicity in grazing animals. The photosensitizing properties of this agent have recently been exploited in models for anti-tumor and anti-viral activity. The cytotoxicity of hypericin and light was assessed in 3T3 mouse fibroblasts using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide)] assay and the lactate dehydrogenase (LDH) leakage assay. Membrane damage was assessed in swine erythrocytes using hemolysis, potassium (K+) leakage and formation of lipid hydroperoxides. Concentration- and light-dependent decreases in fibroblast viability were seen starting at hypericin concentrations of 1.25 microM and light power flux levels of 24 J/cm2 using a visible light source and at 0.417 microM hypericin and a similar light dose using a solar simulator. No LDH leakage was observed at hypericin concentrations up to 30 microM and visible light up to 144 J/cm2. Light-and/or concentration-dependent increases in hemolysis, K+ leakage and formation of lipid hydroperoxides in red blood cell (RBC) membranes were observed, but at concentrations and light doses much greater than those required to induce cytotoxicity in fibroblasts. Lipid peroxidation and hemolysis occurred at 15 microM hypericin and 24 J/cm2 (visible light source). Potassium ion leakage occurred at concentrations and light levels as low as 5 microM and 12 J/cm2 or 15 microM and 4.8 J/cm2 (visible light source) but was still a less sensitive indicator than fibroblast cytotoxicity. Evidence for both type I and type II reactions was shown in RBC membranes by TLC analysis of cholesterol products. In the absence of light, hypericin appears to be relatively nontoxic in the models tested.

L-arginine does not improve cortical perfusion or histopathological outcome in spontaneously hypertensive rats subjected to distal middle cerebral artery photothrombotic occlusion

The potential of nitric oxide (NO) to influence positively or negatively the outcome of mechanically induced focal cerebral ischemia is still controversial. Recent evidence suggests that NO of vascular origin, whether synthesized from exogenously administered L-arginine (L-Arg) or from NO donor compounds, is beneficial but that of neuronal origin is not. However, the therapeutic potential of NO to ameliorate stroke induced by arterial thrombosis has not been reported. We assessed the therapeutic effect of L-Arg administration in spontaneously hypertensive rats (SHR) subjected to permanent photothrombotic occlusion of the distal middle cerebral artery (dMCA). The ipsilateral carotid artery was left unligated to enhance L-Arg delivery into the putative penumbral region. Local CBF (LCBF) was assessed at 30 min by the [14C]iodoantipyrine technique (n = 9), while histological infarct volumes and index of peripheral ischemic cell change were determined at 3 days (n = 7). Rats (n = 9) given 300 mg/kg L-Arg at 18 and 3 h before photothrombotic dMCA occlusion and at 5 min afterward displayed no significant differences in LCBF compared with animals (n = 8) injected with water (the carrier vehicle) and similarly irradiated. Infarct volumes were also similar, being 37.0 +/- 9.7 mm3 (SD) in the vehicle-treated and 49.1 +/- 17.2 mm3 (SD) in the L-Arg-treated groups (both n = 7), as were assessments of ischemic neuronal density in the penumbra. In contrast, L-Arg administered intravenously in a dose of 300 mg/kg to nonischemic SHR (n = 5) increased cortical CBF by approximately 75% during a 70-min observation period. We conclude that thrombotic processes superimposed upon cerebral ischemia may facilitate tissue reactions that offset the potentially beneficial effect of L-Arg, and this caveat must be considered when proposing L-Arg for clinical treatment of focal thrombotic stroke.

Saponins from Mussaenda pubescens

From the hydrophilic fractions of aerial parts of Mussaenda pubescens, three new saponins named mussaendosides D, E and H, along with a known saponin, mussaendoside S, were isolated. Their structures were elucidated on the basis of chemical and spectral evidence.

Depiction of infarct frequency distribution by computer-assisted image mapping in rat brains with middle cerebral artery occlusion. Comparison of photothrombotic and intraluminal suture models

BACKGROUND AND PURPOSE

Histopathologic analysis of experimental brain damage has traditionally been performed by measuring areas of infarction and/or selective neuronal alterations on a section-by-section basis in individual animals. For series containing multiple replicate animals, quantitation of tissue injury is typically performed at similar coronal levels throughout an experimental group. A means of facilitating pictorial group comparisons of these histopathologic alterations between different series of replicate studies is highly desirable.

METHODS

We introduce a newly designed approach to achieve this goal, based on a linear affine transformation that is used to map corresponding sections at the same anatomic level into a common template to yield a frequency distribution map depicting the aggregate data set. We have applied this approach to compare the histopathologic features of two models of middle cerebral artery (MCA) occlusion in rats: (1) photothrombotically induced permanent distal MCA occlusion in spontaneously hypertensive rats (SHR) and (2) temporary MCA occlusion by intraluminal suture in Wistar rats.

RESULTS

The brains of SHR rats with permanent distal MCA occlusion showed a high frequency of infarction involving the dorsolateral and lateral portions of the ipsilateral neocortex, whereas Wistar rats with 90-minute MCA suture occlusion showed a zone of infarction largely concentrated in the dorsolateral portion of the ipsilateral caudoputamen. Infarct frequency distributions for the two animal groups were compared statistically at three corresponding anatomic levels by Fisher's exact test; the resulting statistical parametric maps are shown.

CONCLUSIONS

With the use of frequency distribution maps, the pattern of trends within a group can be observed coronally or three-dimensionally. One can directly access data as to numbers of rats with infarction for any point on the map. Studies performed under different experimental conditions can also be compared with one another by means of the generated data sets.

Immunogenicity and relative attenuation of different vaccinia-rabies virus recombinants

Immunogenicity and relative attenuation were examined for the following Tian Tan strain vaccinia-rabies recombinant viruses: 1) NGc-1, which coexpresses the glycoprotein (G) and nucleocapsid protein (N) of the rabies virus Challenge Virus Standard (CVS) strain; 2) Nc-1, which expresses the CVS N; 3) Gc-2, Gc-3, Gc-4, and Gc-5, which express CVS G via promoters from different vaccinia strains or from different vaccinia genome loci; 4) Ga-1, which expresses the G of rabies virus strain aG; and 5) Gas-1; which expresses the carboxyltruncated G ectodomain (Gs) of strain aG. All but Nc-1 and Gas-1 induced rabies virus neutralizing antibodies (VNAs) and protected groups of mice at very high frequencies from intramuscular (IM) or intracranial (IC) challenge with CVS or SW1 Shanghai dog street rabies virus (SRV); Nc-1 and Gas-1 were partly protective, more frequently against IM challenge. NGc-1 and Gc-5 appeared to induce high levels of VNAs sooner after immunization than the other constructs in mice. Relative attenuation assessed by IM infection of neonatal mice, IC infection of adult mice, and intradermal infection of rabbits with varying doses was best for NGc-1. All the recombinants were at least 100-fold more attenuated than the parent, Tian Tan vaccinia virus. Gc-2, Gc-3, Gc-4, Gc-5, and NGc-1 induced VNAs after immunization of dogs, and a subset of VNA-positive animals vaccinated with NGc-1 or Gc-3 were protected against an otherwise lethal IM injection of SRV at 21 days after vaccination.

Complex alternative RNA processing generates an unexpected diversity of poly(A) polymerase isoforms

Multiple forms of poly(A) polymerase (PAPs I, II, and III) cDNA have previously been isolated from bovine, human, and/or frog cDNA libraries. PAPs I and II are long forms of the enzyme that contain four functional domains: an apparent ribonucleoprotein-type RNA-binding domain, a catalytic region that may be related to the polymerase module, two nuclear localization signals (NLSs I and 2), and a C-terminal Ser/Thr-rich region. PAP III would encode a truncated protein that lacks the NLSs and the S/T-rich region. To investigate further the structure and expression of these forms, we isolated the mouse PAP gene and an intronless pseudogene from a mouse liver genomic library. The structure of the gene indicates that different forms of PAP are produced by alternative splicing (PAPs I and II) or by competition between polyadenylation and splicing (PAP III). The pseudogene appears to reflect yet another form of long PAP, which we call PAP IV. Mouse PAP III and two additional truncated forms, PAPs V and VI, which would be produced by use of poly(A) sites in adjacent introns, were also isolated from a mouse brain cDNA library. RNase protection and reverse transcription-PCR analyses showed that PAP II, V, and VI are expressed in all tissues tested but that PAP I and/or IV and III are tissue specific. However, immunoblot analysis detected only the long forms, raising the possibility that the short-form RNAs are not translated. Purified recombinant baculovirus-expressed PAPs were tested in several in vitro assays, and the short forms were found to be inactive. We discuss the possible significance of this complex expression pattern.

Localization and distribution of angiotensin II in the rat epididymis

The localization and distribution of angiotensin II (Ang II) in the rat epididymis was studied using immunohistochemical and RIA techniques. The immunohistochemical results showed that Ang II-like immunoreactivity progressively increased along the length of the rat epididymis (cauda > corpus >> caput) and was predominately localized in the basal region of the epididymal epithelium. Occasionally, immunostaining of lighter intensity was also found in the apical region. The concentration of Ang II in cultured rat cauda epididymal epithelial cells was further measured by RIA. In addition to that found in cultured epithelial cells, Ang II activity was also detected in the culture medium, suggesting a secretory role of the epithelium. These findings suggest that Ang II could be derived locally from epididymal epithelium and that it could play a role in local regulation of epithelial transport and, possibly, in the maintenance of sperm function as well, by exerting its paracrine and/or autocrine effect in various regions of the epididymis.

Evidence for independent Cl- and HCO3- secretion and involvement of an apical Na(+)-HCO3- cotransporter in cultured rat epididymal epithelia

Electrogenic chloride and bicarbonate secretion by cultured rat epididymal epithelia was studied using the short-circuit current (ISC) technique. When incubated in normal solution, 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (cpt-cAMP) caused a rise in the ISC, which was attributable to Cl- and HCO3- secretion. Cl- secretion was found to contribute to the initial transient phase, whereas HCO3- secretion contributed to the sustained phase of the response. HCO3- secretion involves a basolaterally placed Na(+)-H+ exchanger and apical anion channel, most probably the cystic fibrosis transmembrane conductance regulator (CFTR). There is also evidence that an apical electrogenic Na(+)-HCO3- cotransporter is involved in HCO3- exit. CFTR accounted for 70% of HCO3- secretion, while the Na(+)-HCO3- cotransporter accounted for 30%. The possibility that the cotransporter may serve as an alternative pathway for HCO3- secretion in cystic fibrosis is discussed.

Effects of alveolar macrophage conditioned media from interstitial lung disease patients on the procollagen mRNA expression in human lung fibroblasts

Progressive inflammation and fibrosis are the central processes in the pathogenesis of pulmonary fibrosis. It is believed that macrophages in areas of chronically inflamed lung play a key role in fibrotic response. Therefore, we investigated the effects of alveolar macrophage (Am phi) conditioned media from interstitial lung disease (ILD) patients on lung fibroblast proliferation and procollagen mRNA expression. After stimulating with Am phi conditioned media from ILD patients, the fibroblast proliferation increased 71.4% compared with the control, but for media from bronchial carcinoma (BC) patients, it just increased 14.3%. There is a significant difference between the two groups (P < 0.05). The procollagen alpha, (I) mRNA in fibroblasts stimulated with Am phi conditioned media from ILD patients was increased 21.3%, and alpha 1 (III) was 37.2% higher than control (P < 0.05). It increased 6.8% and 12.8% for media from BC patients respectively, but there was no difference when compared to the control. We considered that Am phi from ILD patients might be in an activated state and could release some growth factors to stimulate fibroblast proliferation and promote collagen DNA expression.

[Anti-embryonation immunity and cultivation of Schistosoma japonicum eggs in vitro]

OBJECTIVE

To study anti-SIEA super-immune sera against the influence on schistosoma japonicum in vitro cultivation of newly laid eggs by adult worms, their hatches and development.

METHODS

The adult worm pairs of Schistosoma japonicum were collected from test animals, portae vena which infected with the worms for 38-45 days. The worm pairs were injected divided into control group with normal rabbit sera and experimental group with anti-SIEA super-immune sera. The output of newly laid eggs and the embryonic development were observed with immunofluorescence staining.

RESULTS

Female worms cultured in vitro with normal rabbit serum not only discharged eggs already contained in its uterus, but also produced newly formed ones. They however, did not occur in female worms cultured with anti-SIEA super-immune sera and the output of eggs by the latter was much lower than that of the former. There was also a marked decrease in the proportion of developed eggs in the experimental group compared with that in the control group. In addition, immunofluorescence staining of immature eggs and female worms by anti-SIEA super-immune sera showed that a lightened fluorescence was not only seen in the embryonic cells of immature eggs, but also in the vitelaria and in the internal membrane tissue of gut cavity of the female worms.

CONCLUSION

SIEA was possibly involved in the immunity against egg development and fecundity of schistosoma japonicum.

Experimental allergic encephalomyelitis in the rat is inhibited by aminoguanidine, an inhibitor of nitric oxide synthase

This study assessed the role of de novo nitric oxide (NO) production in the pathogenesis of experimental allergic encephalomyelitis (EAE) by using aminoguanidine (AG), an inhibitor of nitric oxide synthase (NOS), which preferentially inhibits the cytokine- and endotoxin-inducible isoform of NOS versus the constitutive isoforms consisting of endothelial and neuronal NOS. The maximum clinical severity of EAE and the duration of illness were significantly reduced or totally inhibited by twice daily subcutaneous injection of 100 mg/kg body weight AG. Histochemical staining for NADPH diaphorase, which detects enzymatic activity of NOS, revealed positive reactivity in untreated EAE rats both in parenchymal blood vessel walls and in anterior horn cell neurons, while normal rats and rats with EAE treated with AG showed predominantly the neuronal positivity. Moreover, this NADPH staining pattern was further supported by the immunohistochemical findings that endothelial NOS (eNOS) expression was increased in blood vessels in the inflamed lesions of untreated EAE rats and that inducible NOS (iNOS) was detected in some inflammatory cells, while treatment with AG could significantly reduce both iNOS and eNOS production. These results suggest that: (i) both iNOS and eNOS are upregulated in inflamed areas of the rat central nervous system in EAE; (ii) increased NO production plays a role in the development of clinical signs in EAE; and (iii) selective inhibitors of iNOS and/or eNOS may have therapeutic potential for the treatment of certain autoimmune diseases.

Neurobehavioral consequences of induced spreading depression following photothrombotic middle cerebral artery occlusion

In a model of experimental focal cerebral ischemia, we have recently reported a strong correlation between the magnitude of ischemic depolarizations in the peri-infarct borderzone and the extent of histological injury. In the present study, we assessed the neurobehavioral consequences of spontaneously occurring and induced ischemic depolarizations in rats following middle cerebral artery (MCA) occlusion, as well as the effects of induced spreading depression (SD) in intact animals. Halothane-anesthetized, artificially ventilated Sprague-Dawley rats underwent photothrombotic MCA occlusion coupled with ipsilateral common carotid artery (CCA) occlusion. The electroencephalogram and direct current (DC) potential were recorded in the parietal infarct borderzone-corresponding to the cortical forelimb area-for 3 h following MCA occlusion. Group 1 rats (n = 9) received MCA/CCA occlusion, and the spontaneously occurring negative DC shifts were recorded in the ischemic borderzone. In Group 2 animals (n = 9), the (non-ischemic) frontal pole of the ipsilateral hemisphere was electrically stimulated in order to double the frequency of peri-infarct DC shifts occurring over the initial 3 h postocclusion. Group 3 consisted of intact rats (n = 3) in which SD was repeatedly evoked in the frontal pole. Four animals served as sham-operated controls. A battery of sensorimotor behavioral tests, consisting of beam balance, postural reflex and elicited forelimb placing, was applied in a blinded fashion. Sham controls and animals of Groups 1 and 2 were tested 24 h after surgery, and Group 3 rats were tested 2, 6 and 24 h after generation of SDs. A cumulative neurobehavioral index, ranging from 0 to 144, was calculated by adding the individual test results. Brains were perfusion-fixed 24 h following surgery for calculation of volumes of infarction and scattered neuronal injury. Functional outcome at 24 h was significantly worse in Group 2 animals (spontaneous plus induced ischemic depolarizations) (neurobehavior index 43 +/- 19, mean +/- S.D.) compared to Group 1 rats, in which only spontaneous depolarizations occurred (neurobehavior index 24 +/- 19, P < 0.05). The cumulative neurobehavioral index of Group 1 and 2 animals correlated positively with the volume of total ischemic injury (r = 0.765, P < 0.001) and with the frequency of ischemic depolarizations (r = 0.474, P < 0.05). Correlations between severe forelimb placing deficits and severe degrees of histological injury (necrosis or ischemic cell change) in the corresponding primary sensorimotor cortical region FR1 were significant in these rats. Group 3 rats showed severe neurobehavioral deficits at 2 and 6 h following SD stimulation (index 57 +/- 1 and 39 +/- 1, respectively) but returned to normal at 24 h (4 +/- 0). The findings indicate that cortical spreading depression is accompanied by transient neurobehavioral deterioration and that SD in the ischemic hemisphere of animals subjected to MCA occlusion worsened functional outcome 24 h after surgery.

Three-dimensional metabolic and hemodynamic imaging of the normal and ischemic rat brain

Unique insights into the topography of local metabolism/blood flow interrelationships in focal cerebral ischemia have afforded by the recent development of powerful image-processing techniques permitting three-dimensional (3D) autoradiographic image-averaging and analysis of replicate studies by a novel method termed "disparity analysis". This method, based upon a linear affine transformation model, directly estimates scaling, translation and rotation parameters simultaneously. The method was validated in awake Wister rats studied for local cerebral glucose metabolism (lCMRgl) with 14C-2-deoxyglucose. Brains were subserially sectioned, aligned by disparity analysis, and mapped into a common template so as to generate aggregate 3D data sets of the mean and standard deviation of the entire series (n = 9). Internal anatomic architecture was faithfully represented in the average image, and Fourier analysis revealed satisfactory retention of low-frequency information. The method was then applied to study metabolism/blood flow relationships in the acute focal ischemic penumbra of Sprague-Dawley rats subjected to distal photothrombotic middle cerebral artery (MCA) occlusion, coupled with permanent ipsilateral and 1 h contralateral common carotid artery occlusions. Matched series were studied for lCBF at 1.5 h and for lCMRgl at 1.25-2 h post-occlusion. The averaged lCBF image revealed the ischemic penumbra (defined as lCBF 20-40% of control) to form a "shell" around the cortical ischemic core and a confluent aggregate at the anterior and posterior poles of the core-zone. lCMRgl in the penumbra was heterogeneous, ranging from near-normal to markedly increased. An average lCMRgl/lCBF ratio data set revealed marked metabolism-flow uncoupling in penumbral pixels, averaging nearly five-fold above control ratio values. Sustained deflections of the DC potential were recorded in the penumbra, the site of marked uncoupling. This analysis defined for the first time the 3D topography of the ischemic penumbra and substantiated marked metabolism/flow dissociation, which is believed to be a metabolic consequence of the energy demand imposed by repeated peri-infarct depolarizations.

Studies on bioactive saponins from Chinese medicinal plants

In our recent studies on bioactive saponins, two Chinese medicinal plants: Mussaenda pubescens Ait.f (Rubiaceae) and Clematis chinensis Osbeck (Ranunculaceae), were investigated. Of the two medicinal plants, M. pubescens is a Chinese folk medicine which has been used as a diuretic, antiphlogistic, diaphoretic and antipyretic agent, and has also been used to detoxify mushroom poisons and to terminate early pregnancy. Clematis chinensis is a Chinese traditional medicine which has been used as an analgesic, diuretic, antitumor, antiinflammatory and insecticidal agent for ages. As a result of our studies, eighteen saponins were identified from M. pubescens, among which seventeen were new compounds, while eleven saponins were isolated from C. chinensis, three of which were new compounds. In the course of our structural studies, mass fragment analysis in FAB-mass spectra and 1H- and 13C-NMR spectra were used to determine the structures of the sapogenin and oligosaccharide moieties. In those more complicated and minor saponins, various 2D-NMR experiments were carried out on 400-, 500- or 600-MHz NMR instruments, which permitted the identification of new sapogenins in glycoside form. In addition, it was also possible to assign all the proton and carbon signals of the sugar units on the basis of 1H-1H DQF COSY, TOCSY and HMQC spectra, which further permitted the establishment of linkage sites and sequences among the sugar units and aglycones by means of NOESY, ROESY and HMBC spectra. When the proton signals of sugar units are overlapped seriously in 1H-NMR spectra, peracetylation is a very helpful technique which can spread proton signals in wider range, thus simplifying their assignment by means of 2D-NMR spectra. When some of the sugar proton signals of a peracetylate are also overlapped coincidentally, alternation of deuterated solvents for measuring NMR spectra can circumvent the difficulties. Pharmacological tests indicated that mussaendoside O, the most abundant saponin from M. pubescens, can inhibit significantly the secretions of the lachrymal and salivary glands induced by galanthamine, and can also inhibit the contraction of the isolated longitudinal muscle strip from guinea pig ileum evoked by an M-Ach receptor agonist (carbachol, 10(-6) M) at concentrations of 10(-4) and 10(-5) M. From these results, the saponin should be an antagonist of the M-Ach receptor, and was presumed to be responsible for its antitoxicity activity toward some mushroom poisons of medicinal plant origin. In addition, mussaendoside O also showed immunopromotive and hemolytic activities.

The role of macrophages, perivascular cells, and microglial cells in the pathogenesis of experimental autoimmune encephalomyelitis

Clinical signs of experimental autoimmune encephalomyelitis (EAE) in rats can be suppressed by treatment with liposomes containing dichloromethylene diphosphonate (Cl2MDP liposomes). Here we investigated whether besides the blood-borne macrophages also ED2+ perivascular cells and microglia are affected by this treatment. For this purpose we examined the central nervous system of bone marrow chimeras in which EAE was induced with encephalitogenic T cells. Quantification of cell numbers of various cell types in inflammatory lesions in the spinal cord showed that after treatment with Cl2MDP liposomes more than 95% of the bone marrow derived (I1-69+) macrophages were eliminated. In addition the number of ED2+ perivascular cells were seen to be decreased by 68% as compared to ED2+ cells in control liposome treated animals. However the number of these perivascular cells in Cl2MDP liposome treated animals did not differ from the number of perivascular cells in naive animals, indicating that only newly recruited, inflammation associated, ED2+ macrophages were eliminated. Moreover, detection of degenerating nuclei by in situ nick translation (ISNT) in combination with staining for ED1 or ED2 showed that in the perivascular space no degenerating cells were present. Cl2MDP liposome treatment furthermore decreased the numbers of T cells infiltrating the parenchyma by more than 50%. Instead T cells were found in large numbers in the perivascular space. Microglia did not seem to be eliminated by Cl2MDP liposome treatment as shown by the absence of ED1+/ISNT+ cells in the CNS parenchyma. However the number of ED1+ (I1-69-) microglial cells decreased by more than 80%, indicating that the activation of this cell type was impaired. It is concluded that bone marrow derived macrophages play an important role in the pathogenesis of EAE via interactions with lymphocytes and the activation of resident microglia.

HU-211, a novel noncompetitive N-methyl-D-aspartate antagonist, improves neurological deficit and reduces infarct volume after reversible focal cerebral ischemia in the rat

BACKGROUND AND PURPOSE

HU-211 is a nonpsychotropic cannabinoid analogue that has been shown to act as a functional N-methyl-D-aspartate receptor blocker. We investigated the neuroprotective efficacy of HU-211 in a model of reversible middle cerebral artery occlusion (MCAo) in rats.

METHODS

Male Wistar rats were anesthetized with halothane and subjected to 90 minutes of temporary MCAo by retrograde insertion of an intraluminal nylon suture, coated with poly-L-lysine, through the external carotid artery into the internal carotid artery and MCA. The drug (HU-211 in cosolvent, 4 mg/kg IV) or vehicle was administered in a blinded fashion 70 minutes after onset of MCAo. Behavioral tests were evaluated during occlusion (60 minutes) and for a 3-day period after MCAo. Three days after MCAo, brains were perfusion-fixed, and infarct volumes were determined.

RESULTS

HU-211 significantly improved the neurological score compared with vehicle during the 3 days after MCAo. Treatment with HU-211 also significantly reduced both infarct volume (mean +/- SEM, 66.6 +/- 12.5 versus 149.8 +/- 36.3 mm3) and brain swelling (2.61 +/- 1.33% versus 6.66 +/- 1.24%) compared with vehicle-treated rats (n = 17 in each group).

CONCLUSIONS

These results demonstrate the neuroprotective ability of HU-211 in focal cerebral ischemia as judged by neurological score, infarct size, and brain swelling. Reversible MCAo with the use of a poly-L-lysine-coated intraluminal suture proved to be a reliable and effective modification of this technique, yielding consistent results.

A dual role for nitric oxide in NMDA-mediated toxicity in vivo

Nitric oxide has been implicated in N-methyl-D-aspartate (NMDA)-mediated damage in vitro; however, its role in excitotoxic damage in vivo is not clear. In the present study we evaluated the histopathological and hemodynamic consequences of intrastriatal injections of various doses of NMDA and determined the effects of nitric oxide synthase inhibition on these changes. NMDA was injected into the striatum at doses of 50, 150, and 300 nmol with or without N omega-nitro-L-arginine methyl ester (L-NAME; 100 micrograms, locally). Three days following injections histopathological assessment was performed by morphometric analysis of the lesion area in multiple sections taken from the anterior to the posterior borders of the lesion. In animals injected with 150 and 300 nmol of NMDA (+/- L-NAME), local CBF (lCBF) was determined 30 min following injections using 14C-iodoantipyrine autoradiography. All NMDA-treated animals showed a well-demarcated lesion extending beyond the injection site. The volume of the lesion correlated significantly with the NMDA dose injected. The effects of L-NAME on lesion size were dependent on the dose of the NMDA. The lesion induced by 50 nmol of NMDA was not affected by L-NAME. With a dose of 150 nmol of NMDA, L-NAME induced a 43% increase in lesion volume. In contrast, a 38% decrease in lesion size was observed in animals treated with 300 nmol of NMDA combined with L-NAME. At a dose of 150 nmol, NMDA induced a significant elevation in lCBF, which was restricted to regions close to the injection site including the center areas of the anterior and middle striatum. The increase in lCBF observed with 150 nmol of NMDA was significantly attenuated in the NMDA + L-NAME-treated group. The lCBF changes induced by 300 nmol of NMDA were not significantly different from those in the 150-nmol group; however, the extent of the regions involved was larger. The increases in lCBF were observed in all striatal regions including the central and peripheral areas. L-NAME did not have a significant effect on the lCBF changes induced by NMDA at a dose of 300 nmol. These data suggest that in vivo the involvement of nitric oxide in NMDA toxicity depends on the NMDA dose and on the participation of hemodynamic mechanisms secondary to NMDA exposure.

[Human papillomavirus, human cytomegalovirus and p53 gene in cervical carcinoma]

OBJECTIVE

To investigate the role of human papillomavirus (HPV) human cytomegalovirus (HCMV) infections and p53 gene mutations in the oncogenesis of cervical cancer and to clarify the association between p53 inactivation and the presence of HPV DNA.

METHODS

We examined 38 primary cervical carcinomas and 21 normal cervical specimens for the presence of HPV and HCMV DNA sequences by multiple primers PCR and nest primers PCR. The structure of p53 gene (exons 6-8) was also analyzed by PCR-SSCP silver staining method.

RESULTS

Mutations of p53 gene (exon 7) were detected in 2 of 38 tumors. One of the cases with p53 mutation was positive for HPV 16 and two positive for HCMV. HPV 16 and 18 infections were noted in 63.2% (24/38) of the tumors, the positive rate of HCMV was 84.2% (32/38). However, HPV 16,18 and HCMV infection occurred in 4.8% and 38.1% respectively in 21 normal cervical specimens. 21 of the 24 HPV 16,18 positive tumors were also HCMV positive, but none of the normal cervical tissues was infected with both HPV and HCMV.

CONCLUSION

Detection of p53 mutations in cervical carcinoma is infrequent and apparently independent of HPV infection. Cervical carcinoma is strongly associated with HPV 16 and 18 infection. A synergistic interaction may occur between HPV and HCMV infections in the oncogenesis of cervical cancer.

Protein kinase C regulates pleckstrin by phosphorylation of sites adjacent to the N-terminal pleckstrin homology domain

Pleckstrin is a substrate for protein kinase C in activated platelets that contains at its N and C termini two of the pleckstrin homology (PH) domains that have been proposed to mediate protein-protein and protein-lipid interactions. We have recently shown that pleckstrin can inhibit agonist-induced phosphoinositide hydrolysis and that this inhibition requires an intact N-terminal PH domain (residues 6 to 99). In the present studies, we have identified the sites of phosphorylation in pleckstrin and examined their contribution to pleckstrin function. In human platelets activated with thrombin or phorbol esters, and in COS-1 cells expressing pleckstrin, a combination of phosphopeptide analysis and site-directed mutagenesis shows that three residues in the intervening sequence between the two pleckstrin PH domains become phosphorylated: Ser113, Thr114, and Ser117. Replacing all three of these sites with glycine decreased phosphorylation by > 90% and reduced pleckstrin's ability to inhibit phosphoinositide hydrolysis by as much as 80%. Replacing the phosphorylation sites with alanine residues had a similar effect, while substitution with aspartate, glutamate, or lysine residues produced pleckstrin variants that were fully active even in the absence of phosphorylation. These results suggest that phosphorylation enhances pleckstrin's activity by introducing a cluster of charges into a region adjacent to, but not within, the N-terminal PH domain. This may have an allosteric effect on the N-terminal PH domain, regulating its interaction with other molecules necessary for the inhibition of phosphoinositide hydrolysis.

X-ray imaging using amorphous selenium: feasibility of a flat panel self-scanned detector for digital radiology

We investigate a concept for making a large area, flat-panel detector for digital radiology. It employs an x-ray sensitive photoconductor to convert incident x-radiation to a charge image which is then electronically read out with a large area integrated circuit. The large area integrated circuit, also called an active matrix, consists of a two-dimensional array of thin film transistors (TFTs). The potential advantages of the flat-panel detector for digital radiography include: instantaneous digital radiographs without operator intervention; compact size approaching that of a screen-film cassette and thus compatibility with existing x-ray equipment; high quantum efficiency combined with high resolution. Its potential advantages over the x-ray image intensifier (XRII)/video systems for fluoroscopy include: compactness; geometric accuracy; high resolution, and absence of veiling glare. The feasibility of the detector for digital radiology was investigated using the properties of a particular photoconductor (amorphous selenium) and active matrix array (with cadmium selenide TFTs). The results showed that it can potentially satisfy the detector design requirements for radiography (e.g., chest radiography and mammography). For fluoroscopy, the images can be obtained in real-time but the detector is not quantum noise limited below the mean exposure rate typically used in fluoroscopy. Possible improvements in x-ray sensitivity and noise performance for the application in fluoroscopy are discussed.