Post-ischemic administration of DY-9760e, a novel calmodulin antagonist, reduced infarct volume in the permanent focal ischemia model of spontaneously hypertensive rat

We assessed the effect of a novel calmodulin antagonist, DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate) in a spontaneously hypertensive rat (SHR) permanent focal cerebral ischemia. In experiment I, the left middle cerebral artery was permanently occluded in 62 SHRs. DY-9760e (0.5 mg kg(-1) h(-1)) or vehicle alone were administered continuously i.v. for 6 h, beginning 0, 30, or 60 min after the arterial occlusion. The infarct volume was measured 24 h of ischemia. In experiment II, the effect of DY-9760e on CBF was assessed in 10 SHRs. Administration without a delay resulted in a mean infarct volume of 166.7 +/- 21.0 mm3 (vehicle; n = 10) and 125.1 +/- 31.8 mm3 (DY-9760e; n = 9). Administration with a 30 min delay resulted in a mean infarct volume of 173.2 +/- 32.4 mm3 (vehicle; n = 12) and 143.3 +/- 35.3 mm3 (DY-9760e; n = 11). Dy-9760e significantly reduced the infarct under these conditions (p < 0.05). The administration with a 60 min delay failed to reduce the infarct. DY-9760e had no effect on the CBF. Continuous i.v. administration of DY-9760e reduced infarct volume in a SHR permanent focal ischemia without affecting ischemic CBF.

Sphingolipid biosynthesis by L-PDMP after rat MCA occlusion

L-PDMP (L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol) exhibits stimulatory effects on glycosphingolipid biosynthesis and its neurotrophic actions in cultured neuron. The effects of intraperitoneal administration of L-PDMP on sphingolipid metabolism and behavioral changes in the rat following permanent occlusion of the left middle cerebral artery (MCA) were investigated. The L-PDMP treatment induced increases in glucosylceramide (ganglioside precursor) and sphingomyelin (SM) levels in the ischemic cerebral cortex, and improved acquisition of memory and learning in the Morris water maze task. The pharmacological effects of L-PDMP have been proposed to have a significant activity on promoting cell survival and improving neural functions.

Rewarming eliminates the protective effect of cooling against delayed neuronal death

Mild intra-ischemic hypothermia provides neuroprotection against delayed neuronal death in the hippocampal CA1. It has recently been reported that reduction in the metabolic rate of arachidonic acid (AA) liberated during ischemia might contribute to this neuroprotection. To examine whether rewarming during the early period of recirculation accelerates AA consumption and eliminates the neuroprotection, we measured the levels of AA in the hippocampus after various recirculation times under normothermia and hypothermia with or without rewarming. The tendency for AA to disappear was significantly different between each pair of groups. Histological examination 7 days after ischemia revealed no protection in the rewarmed group. These results suggest that neuronal injury during rewarming after hypothermia may be attributed to the rate of AA metabolism.

Interphase detection of immunoglobulin heavy chain gene translocations with specific oncogene loci in 173 patients with B-cell lymphoma

To detect immunoglobulin heavy chain (IGH) gene translocations with specific oncogene loci, we established an interphase cytogenetic approach using double-color fluorescence in situ hybridization (DC-FISH), which we used to analyze 173 patients with B-cell lymphoma. DC-FISH using the IGH gene (14q32.3) in combination with c-MYC (8q24.1), BCL1 (11q13.3), BCL2 (18q21.3), BCL6 (3q27), and PAX-5 (9p13) gene probes detected IGH translocations in 70 (40.5%) of 173 patients. The partner genes involved in IGH translocations were identified in 56 (80%) of 70 patients, and fusion of the IGH gene with specific oncogenes was detected in 53 of 56 patients, particularly in interphase nuclei of 28 patients for whom cytogenetic analysis was not informative. The most common partner gene was BCL2 (19 patients; 27% of IGH translocation-positive patients), followed by BCL6 (16; 23%), BCL1 (11; 16%), c-MYC (7; 10%), and PAX-5 (2; 3%). These oncogenes were closely associated with subtypes of B-cell lymphoma. The other partners were 19q13 (BCL3), 6p25 (MUM1/IRF4), 1q36, and chromosome 8 identified in one patient each. Six of the nine patients with add(14)(q32) showed a BCL6/IGH translocation. Double translocations of the IGH gene were found in three patients; c-MYC+BCL1, c-MYC+BCL2, and c-MYC+BCL6 in each one. Interphase FISH using specific IGH-translocation probes is valuable for defining clinically meaningful subgroups of B-cell lymphoma.

Structural conversion between open and closed forms of radixin: low-angle shadowing electron microscopy

The function of ERM (ezrin/radixin/moesin) proteins as general cross-linkers between actin filaments and plasma membranes is regulated downstream of Rho, through the transition between active and inactive forms. To directly examine the conformational change between the active and inactive forms of ERM proteins, we applied low-angle rotary-shadowing electron microscopy to the radixin molecules, wild-type, T564A-non-phosphorylated-type, and T564E-phosphorylated-type, since most of the active forms are reportedly stabilized in cells by the C-terminal threonine phosphorylation. As a result, the T564A- and wild-type radixin molecules yielded the globular closed forms, approximately 8-14 nm in diameter, with some striations on their surfaces. In contrast, the T564E-radixin molecules tended to take elongated open forms, in which two globular structures measuring approximately 8 nm and approximately 5 nm in diameter were associated with both ends of the filamentous structures. The filamentous structure took either a approximately 20-25 nm-long straight course or a folded course. Taken together with the biochemical and the crystal structural results obtained to date, the closed and open forms represent the inactive and active forms of radixin as cross-linkers between actin filaments and plasma membranes.

Amelioration of insulin resistance in diabetic ob/ob mice by a new type of orally active insulin-mimetic vanadyl complex: bis(1-oxy-2-pyridinethiolato)oxovanadium(IV) with VO(S(2)O(2)) coordination mode

Recently, we have shown that a newly synthesized vanadyl complex, bis(1-oxy-2-pyridinethiolato)oxovanadium(IV), VO(opt)(2), is a potent orally active insulin-mimetic in treating streptozotocin-induced diabetes in rats, with long-term action. In the present study, the anti-diabetic effect of VO(opt)(2) and its mechanism in ob/ob mice, an obese non-insulin-dependent diabetes mellitus (NIDDM) animal model, was investigated. In ob/ob mice, 15-day oral treatment with VO(opt)(2) resulted in a dose-dependent decrease in the levels of glucose, insulin and triglyceride in blood. VO(opt)(2) was also effective in ameliorating impaired glucose tolerance in ob/ob mice, when an oral glucose tolerance test was performed after treatment with VO(opt)(2). Tumor necrosis factor-alpha (TNF-alpha) is a key component of obesity-diabetes link, we therefore examined the attenuating effect of VO(opt)(2) on impaired insulin signal transduction induced by TNF-alpha. Elevated expression of TNF-alpha was observed in the epididymal and subcutaneous fat tissues of ob/ob mice. Incubation of 3T3-L1, mouse adipocytes, with TNF-alpha reduced the phosphorylation of insulin receptor substrate-1 (IRS-1), whereas VO(opt)(2) treatment resulted in an enhancement of IRS-1 phosphorylation, irrespective of the presence or absence of TNF-alpha. Overall, the present study demonstrates that VO(opt)(2) exerts an anti-diabetic effect in ob/ob mice by ameliorating impaired glucose tolerance, and furthermore, attenuates the TNF-alpha-induced decrease in IRS-1 phosphorylation in adipocytes. These results suggest that the anti-diabetic action of VO(opt)(2) is derived from an attenuation of a TNF-alpha induced impaired insulin signal transduction via inhibition of protein tyrosine phosphatase, providing a potential clinical utility for VO(opt)(2) in the treatment of NIDDM.

[A study on the clinical features of pulmonary tuberculosis in elderly patients]

The clinical findings of pulmonary tuberculosis in elderly patients aged 75 years of age or older (elderly group) were compared with the middle-aged patients aged between 45 and 54 years of age (middle-aged group) and the young patients aged 34 years of age or younger (young group). The elderly patients who died in hospital were also compared with the elderly patients who survived. Study subjects were culture-positive pulmonary tuberculosis patients who were discharged from our hospital from December 1996 to November 1998. There were 79 patients in the elderly group, 95 in the middle-aged group, and 88 in the young group. The results were as follows. 1) The male/female ratio was significantly lower in the elderly group (1.9:1) than the middle-aged group (6.9:1). 2) Complication was noted more frequently in the elderly group. However, diabetes mellitus was noted less frequently in the elderly group (12.7%) than the middle-aged group (28.4%). 3) The frequency of cavitation was lower in the elderly group (59.5%) than the middle-aged group (87.4%). 4) The fever over 38 degrees C was noted less frequently in the elderly group (17.7%) than the other groups, while the frequency of the fever over 37 degrees C showed no significant difference between the elderly group and the other groups. 5) The frequencies of hypoalbuminemia and appetite loss were higher in the elderly group than the other groups. 6) The elderly group showed high mortality rate of 31.6%. The complication with cerebrovascular disease was noted significantly higher in the patients who died in hospital than those who survived. The frequency of widespread infiltrates, fever over 38 degrees C, neutrophilia, hypoalbuminemia and appetite loss were all significantly higher in the patients who died in hospital while their sputa were still positive on culture than those who survived. Our study clearly showed the features of elderly pulmonary tuberculosis patients in comparison with middle-aged patients and young patients. These features are very important to suspect the diagnosis of pulmonary tuberculosis in elderly patients with some atypical manifestation. Our study also suggests that the delay in diagnosing tuberculosis causes more frequently the patients' deterioration and death in elderly patients than in middle-aged patients and young patients.

Differential effects of activity and climate on onset of subarachnoid hemorrhage

Conflicting findings of the effect of climate on onset of subarachnoid hemorrhage (SAH) may result from the influence of strenuous activities which can trigger aneurysmal rupture independent of climatological factors. The effect of climate and patient activities on onset of SAH were analyzed. The clinical records of 786 consecutive patients with aneurysmal SAH admitted to our hospital for 10 years were reviewed. Activities at onset were categorized according to the intensity of strain at onset. Seasonal variation, circannual cyclic trend, and association with 90 meteorological factors were examined in each category and the results were compared between categories. Bimonthly occurrence in the light strain group showed a significant seasonal variation and cyclic trend with two peaks in early spring and fall, whereas no significant trend was detected in the overall patients and in the heavy strain group. The significant meteorological factors were global solar radiation, sunshine hours, changes in mean and minimum temperature and mean vapor pressure from the previous day, and minimum pressure in the previous 7 days. Lower global solar radiation in the light strain group was associated with onset with the lowest p value (p = 0.0046). No factors were significant in the heavy strain group. There is some evidence of the possible influence of climatological factors on onset of SAH without strenuous activity. Strenuous activity seems to affect onset more strongly, which masks any effect of climate.

Formation of the single-layer beta-sheet of Borrelia burgdorferi OspA in the absence of the C-terminal capping globular domain

Borrelia outer surface protein A (OspA) contains a unique single-layer beta-sheet that connects N and C-terminal globular domains. This single-layer beta-sheet segment (beta-strands 8-10) is highly stable in solution, although it is exposed to the solvent on both faces of the sheet and thus it does not contain a hydrophobic core. Here, we tested whether interactions with the C-terminal domain are essential for the formation of the single-layer beta-sheet. We characterized the solution structure, dynamics and stability of an OspA fragment corresponding to beta-strands 1-12 (termed OspA[27-163]), which lacks a majority of the C-terminal globular domain. Analyses of NMR chemical shifts and backbone nuclear Overhauser effect (NOE) connectivities showed that OspA[27-163] is folded except the 12th and final beta-strand. (1)H-(15)N heteronuclear NOE measurements and amide H-(2)H exchange revealed that the single-layer beta-sheet in this fragment is more flexible than the corresponding region in full-length OspA. Thermal-denaturation experiments using differential scanning calorimetry and NMR spectroscopy revealed that the N-terminal globular domain in the fragment has a conformational stability similar to that of the same region in the full-length protein, and that the single-layer beta-sheet region also has a modest thermal stability. These results demonstrate that the unique single-layer beta-sheet retains its conformation in the absence of its interactions with the C-terminal domain. This fragment is significantly smaller than the full-length OspA, and thus it is expected to facilitate studies of the folding mechanism of this unusual beta-sheet structure.

Regional distribution of ethanolamine plasmalogen in the hippocampal CA1 and CA3 regions and cerebral cortex of the gerbil

Although ethanolamine plasmalogens (EtnPm) are the predominant phospholipids in neural tissue, their physiological role has not been clarified. The biophysical conformation of EtnPm in the proteoliposome enhances the activity of the sodium-calcium exchanger, which has been proposed to induce intracellular calcium ion accumulation during ischemia and early reperfusion. The levels of EtnPm in the areas of the gerbil brain selectively vulnerable to ischemia, namely the hippocampal CA1 and CA3 regions and the cerebral cortex, were measured by high-performance thin-layer chromatography and gas-liquid chromatography. The concentration of EtnPm in the CA1 region, which is the most vulnerable to ischemic and anoxic stress, was 2.6- and 2.7-fold higher than that in the CA3 region and cerebral cortex, respectively. The significantly higher concentration of EtnPm in the hippocampal CA1 region may enhance sodium-calcium exchanger activity and play an important role in the vulnerability of this region to ischemia.

Mechanism of oxidative DNA damage induced by carcinogenic 4-aminobiphenyl

DNA adduct formation is thought to be a major cause of DNA damage by carcinogenic aromatic amines. We investigated the ability of an aromatic amine, 4-aminobiphenyl (4-ABP) and its N-hydroxy metabolite (4-ABP(NHOH)) to cause oxidative DNA damage, using (32)P-labeled human DNA fragments from the p53 tumor suppressor gene and the c-Ha-ras-1 protooncogene. 4-ABP(NHOH) was found to cause Cu(II)-mediated DNA damage, especially at thymine residues. Addition of the endogenous reductant NADH led to dramatic enhancement of this process. Catalase and bathocuproine, a Cu(I)-specific chelator, reduced the amount of DNA damage, suggesting the involvement of H(2)O(2) and Cu(I). 4-ABP(NHOH) dose-dependently induced 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in the presence of Cu(ll) and NADH. 4-ABP(NHOH) conversion to nitrosobiphenyl, as measured by UV-visible spectroscopy, occurred rapidly in the presence of Cu(II), suggesting Cu(II)-mediated autoxidation. Increased amounts of 8-OHdG were found in HL-60 cells compared to the H(2)O(2)-resistant clone HP100 following 4-ABP(NHOH) treatment, further supporting the involvement of H(2)O(2). The present study demonstrates that an N-hydroxy derivative of 4-ABP induces oxidative DNA damage through H(2)O(2) in both a cell-free system and in cultured human cells. We conclude that, in addition to DNA adduct formation, oxidative DNA damage may play an important role in the carcinogenic process of 4-ABP.

Astrocytic swelling in the ipsilateral substantia nigra after occlusion of the middle cerebral artery in rats

BACKGROUND AND PURPOSE

Focal cerebral ischemia results in neuronal changes in remote areas that have fiber connections with the ischemic area. We reported previously that a high-signal-intensity lesion was observed in the substantia nigra after striatal infarction on T2-weighted MR images in both clinical and experimental cases. However, the origin of these changes in signal intensity remains unclear. The aim of this study was to investigate the nigral changes by examining the correlation between the apparent diffusion coefficient (ADC) and the tissue structure.

METHODS

Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Four days after the occlusion, when T2-weighted images revealed the presence of an area of high signal intensity in the ipsilateral substantia nigra, diffusion-weighted imaging was performed using a 4.7-T superconductive MR unit, and the ADCs were calculated and imaged. Histopathologic examination by both light and electron microscopy was performed on day 4 after surgery.

RESULTS

Diffusion-weighted images showed an area of high signal intensity in the ipsilateral substantia nigra, and the ADC map revealed uniform reduction of the ADC in this area. Swelling of astrocytic end-feet was observed, especially in the pars reticulata.

CONCLUSION

These findings suggest that MR changes in the ipsilateral substantia nigra after striatal injury consist mainly of swelling in the astrocytic end-feet.

Characteristic changes in T(2)-value, apparent diffusion coefficient, and ultrastructure of substantia nigra evolving exofocal postischemic neuronal death in rats

To correlate the magnetic resonance (MR) imaging characteristics of exofocal postischemic neuronal death (EPND) in the substantia nigra (SN) with associated histologic changes, we occluded the left middle cerebral artery of rats for 1, 4, 7, or 12 days. Day 1 (post-occlusion) T(2)-weighted images revealed high signal intensity indicative of infarction in the ipsilateral caudate nucleus, putamen, and cortex but not the SN. Diffusion-weighted images (DWIs) on day 1 similarly failed to reveal any changes in the SN. However, on day 4, DWIs revealed high signal intensity in the ipsilateral SN, in which the apparent diffusion coefficient (ADC) transiently decreased (P<0.05) while the T(2)-value increased (P<0.05). These measures returned to and remained at control levels on days 7 and 12. Histologic examination on day 4 revealed dark-staining neurons, markedly swollen perivascular astrocytic end-feet, many swollen neurons with cytoplasmic microvacuoles that mainly originated in the rough endoplasmic reticulum, and strongly roughed neuropils. Reactive astrocytes and dark neurons most frequently appeared on days 7 and 12. The severity of cellular swelling paralleled the change in the ADC. These results demonstrate that a transient high-intensity signal on DWIs, indicative of a decrease in the ADC, is predictive of EPND in the SN.

Long-term administration of oral low-dose topoisomerase II inhibitors, MST-16 and VP-16, for refractory or relapsed non-Hodgkin's lymphoma

It is known that the topoisomerase II inhibitors, MST-16 (sobuzoxane) and VP-16 (etoposide), are effective for the treatment of lymphoma. Five patients with refractory or relapsed non-Hodgkin's lymphoma (NHL) were treated with a combination of oral MST-16 and VP-16 over a long period. Two patients had severely refractory NHL. The remaining 3 patients could not be treated with intensive chemotherapy because of severe organ dysfunction or a poor hematopoietic reserve. All 5 are alive and well after MST-16 and VP-16 treatment. MST-16 and VP-16 are effective for NHL when intensive chemotherapy is ineffective or contraindicated.

Interleukin-1 or tumor necrosis factor-alpha augmented the cytotoxic effect of mycobacteria on human fibroblasts: application to evaluation of pathogenesis of clinical isolates of Mycobacterium tuberculosis and M. avium complex

Mycobacteria-induced in vitro events reflecting human tuberculosis can contribute to the evaluation of the pathogenesis of Mycobacterium tuberculosis (MTB). In this study, we propose such an in vitro method based on live mycobacteria-induced cytotoxicity to human cell lines. When human lung-derived normal fibroblast cell line MRC-5 was infected with various strains of mycobacteria (M. tuberculosis H(37)Rv and H(37) Ra, Mycobacterium avium 427S and 2151SmO, and Mycobacterium bovis BCG Pasteur and Tokyo), the fibroblasts were killed by mycobacteria according to the degree of virulence. Other human originated macrophage (U-937, THP-1), myeloid (HL-60), and epithelial carcinoma (A549) cell lines exhibited a similar cytotoxic response to virulent mycobacteria. MRC-5 was most susceptible to virulent mycobacteria among various human cell lines examined. The cytotoxicity was enhanced by the proinflammatory cytokines, interleukin-1 (IL-1) and tumor necrosis factor-a (TNF-alpha), which in the absence of mycobacteria stimulate the growth of normal human fibroblasts. This in vitro evaluation system was applied to clinical isolates of drug-sensitive MTB (DS-MTB), drug-resistant MTB (DR-MTB) including multidrug-resistant (MDR-MTB), and M. avium complex (MAC). MTB strains (n = 24) exhibited strong cytotoxic activity, but MAC strains (n = 5) had only weak activity. Furthermore, there was no significant difference in cytotoxicity between DS-MTB (n = 11) and DR-MTB (n = 13). Collectively, these results suggest that this new in vitro system is useful for evaluating the pathogenesis of mycobacteria and that there was no difference in the pathogenesis between drug-susceptible and drug-resistant clinical isolates.

Immunohistochemical study of the phosphorylated and activated form of c-Jun NH2-terminal kinase in human aorta

c-Jun NH2-terminal kinase is a key enzyme mediating the cellular response to a variety of extracellular stimuli. In the present study, we performed immunohistochemical studies of the expression of the phosphorylated form of the kinase in 51 human aortas of various ages. The phosphorylated kinase immunoreactivity was strongly detected in vascular smooth muscle cells of the medial vessel layer of atherosclerotic lesions from adults. Immunoreactivity was also strongly detected in similar cells of the intima. On the other hand, immunoreactive phosphorylated kinase was only weakly defected in the medial vascular smooth muscle cells of non-atherosclerotic lesions from adults. We also investigated the expression of the phosphorylated kinase in infant aortas. In contrast to its weak immunoreactivity in adult non-atherosclerotic lesions, the kinase immunoreactivity was detected in high amounts in vascular smooth muscle cells of non-atherosclerotic lesions from infants. Thus, the abundant expression of the phosphorylated kinase in these cells in atherosclerotic lesions of adults and non-atherosclerotic lesions of infants suggests that the activation of c-Jun NH2-terminal kinase may be an important element initiating the proliferation of vascular smooth muscle cells during atherogenesis and aortic development.

Reassessment of monoethylglycinexylidide as preoperative liver function test in a rat model of liver cirrhosis and man

It is known that lidocaine is rapidly metabolized by the hepatic cytochrome P-450 system to form monoethylglycinexylidide (MEGX), its primary metabolite. We analyzed serum MEGX levels experimentally and clinically by fluorescent polarization immunoassay to reassess preoperative liver microsome functions.

EXPERIMENTAL STUDY

Liver cirrhosis was produced in rats by intra-abdominal injection of thioacetamide. MEGX, indocyanine green test (ICG), and liver biochemical variables were measured periodically. Then, survival rates were assessed after the rats received a 70% hepatectomy.

CLINICAL STUDY

MEGX levels were measured in various human patients with chronic hepatitis or liver cirrhosis who underwent hepatectomy. Serum MEGX levels significantly dropped and ICG levels significantly rose with macroscopic and histologic progression of liver cirrhosis in rats. The MEGX levels correlated closely with albumin levels and ICG. Preoperative MEGX and ICG levels of the mortal group of rats differed significantly from those of the survival group with 70% hepatectomy. Furthermore, 100% of the rats with MEGX levels above 40 ng/ml and ICG levels below 1.0%. In the clinical study, MEGX levels were significantly lower in patients with chronic hepatitis or liver cirrhosis than in healthy volunteers and correlated significantly with liver function tests such as albumin, Fischer's ratio, prothrombin time, hepaplastin and ICG. A significant difference was found in MEGX levels between patients receiving lobectomy and those receiving subsegmentectomy or partial hepatectomy. All patients tolerated their operations. Our data indicate that the MEGX test combined with ICG test and Child-Pugh classification is a better predictor of residual liver reserve capacity, and the analysis of hepatic MEGX formation might prove useful for rapid and reliable assessment liver function and choice of surgical treatment.

Acute promyelocytic leukemia with marrow fibrosis at initial presentation: possible involvement of transforming growth factor-beta(1)

Although the occurrence of marrow fibrosis in acute myeloid leukemia has been described, there have been no reports of acute promyelocytic leukemia (APL) associated with marrow fibrosis. Here we describe an APL patient with severe marrow fibrosis at initial presentation. He had the typical manifestations of APL, except for marrow fibrosis. Complete remission was achieved by treatment with all-trans retinoic acid plus chemotherapy, and his marrow fibrosis gradually improved concomitantly with the decrease in leukemic cells. To clarify the mechanism of marrow fibrosis in this patient, we investigated the expression of genes for several cytokines promoting fibrosis by the reverse transcriptase polymerase chain reaction methods. An overexpression of transforming growth factor-beta(1) was noted in his leukemic cells at initial presentation, whereas no increase in expression was observed at the time of relapse when he no longer had marrow fibrosis. These findings suggest that overexpression of transforming growth factor-beta(1) was involved in the development of marrow fibrosis in this APL patient.

Induction of lymphocyte apoptosis in rat liver allograft with ongoing rejection by FTY720

The action mechanism of FTY720, a novel immunosuppressant, is completely different from conventional immunosuppressants. The drug, which triggers apoptosis in murine and human lymphocytes, has a potent immunosuppressive activity to prevent allograft rejection without any severe side-effect. The present study was designed to determine whether FTY720 induces apoptotic cell death in activated lymphocytes infiltrated into liver grafts with ongoing rejection. FTY720 was orally administered at 5 mg/kg to the recipients on day 3 and day 4 after grafting, when the graft rejection was histologically confirmed. The intragraft patterns of IL-2, interferon-gamma (IFN-gamma), perforin, and granzyme B gene expression were detected by reverse transcriptase-polymerase chain reaction. The treatment reversed ongoing rejection and significantly prolonged recipient survival time compared with the control group. Light microscopic observation of the graft sections stained with the DNA nick-end labelling method showed that the apoptosis in the control allografts was mainly induced in hepatocytes, while that in the FTY720-treated allografts was in infiltrated lymphocytes. The rejection therapy with FTY720 did not alter the expression of IL-2, IFN-gamma, and perforin mRNAs, but slightly decreased granzyme B expression. Our results suggest that FTY720 does not alter the intrinsic lymphocyte function to produce the rejection-related cytokines, but strongly induces apoptotic cell death in the activated lymphocytes. Thus, FTY720 affords new insight into the mechanisms underlying improvements in immunosuppressive treatments.

Relationship between terminal QRS distortion on the admission electrocardiogram and the time course of left ventricular wall motion in anterior wall acute myocardial infarction

In order to clarify the time course of left ventricular (LV) wall motion in patients with anterior acute myocardial infarction (AMI) showing terminal QRS distortion on the admission electrocardiogram (ECG), the present study examined 106 patients with their first anterior AMI (< or =6 h) who underwent emergency coronary arteriography and cardiac cathetherization at 1 and 6 months after the infarction. The patients were classified into 2 groups according to the presence (group A, n=23) or absence (group B, n=83) of terminal QRS distortion (emergence of the J point at > or =50% of the R-wave amplitude in leads with QR configuration and/or absence of S waves in leads with RS configuration) on the admission ECG. Group A had a lower LV ejection fraction and more reduced regional wall motion (RWM) in the infarct region at both 1 and 6 months after AMI than group B. The degree of improvement in RWM between 1 and 6 months after AMI was less in group A than in group B (-0.1+/-0.5 vs 0.4+/-0.6 SD/chord, p<0.01). This study indicates that patients with anterior AMI showing terminal QRS distortion on the admission ECG have more severely depressed LV wall motion and less improvement in RWM in the infarct region in the healing stage, suggesting that this sign is an indicator of severe myocardial damage.

Possible involvement of Fyn kinase in ethanol-stimulated Cas tyrosine phosphorylation in rat cerebellum and cerebral cortex

In the present study, we have investigated the effect of intraperitoneal injection of ethanol (3.5 g/kg) on tyrosine phosphorylation in rat brain. Immunoblot analysis using an antiphosphotyrosine antibody revealed that a 130-kDa protein band was detected in the brain extract in response to ethanol administration. This ethanol-stimulated tyrosine phosphorylation of the 130-kDa protein was found in the brain but not in the heart, liver or thymus. The 130-kDa phosphotyrosine-containing protein was identified by immunoprecipitation to be Cas, a crk-associated src substrate. This ethanol-stimulated tyrosine phosphorylation of Cas was observed most prominently in the cerebellum and the cerebral cortex. We further examined the possible involvement of Fyn kinase in ethanol-stimulated Cas tyrosine phosphorylation. Immunecomplex kinase assay showed that Fyn was activated in the cerebellum and cerebral cortex of ethanol-administered rats. Immunoprecipitation experiments also showed that Fyn was co-immunoprecipitated with an anti-Cas antibody in these regions from ethanol-administered rats. Furthermore, exogenous Fyn was shown to phosphorylate Cas from cerebellum and cerebral cortex in vitro. These findings indicate that ethanol stimulates tyrosine phosphorylation of Cas in rat cerebellum and cerebral cortex, and that Fyn may be involved in the process.

Immunolocalization of the mitogen-activated protein kinase signaling pathway in Hassall's corpuscles of the human thymus

In the present study, we investigated the immunohistochemical localization of mitogen-activated protein kinase (MAPK) signaling pathway in the human thymus. Three members of MAPK, the extracellular signal-regulated kinase (ERK), the c-Jun N-terminal kinase (JNK) and the p38 kinase, showed differential expression patterns in the thymus medulla. The phosphorylated form of ERK (p-ERK) was abundantly present in the outer layer of Hassall's corpuscles, and the phosphorylated form of p38 kinase (p-p38 kinase) was present in the entire Hassall's corpuscles. The phosphorylated form of JNK (p-JNK) was expressed in medullary thymocytes. We also examined localization of MAPK kinases (MAPKK or MEK) which specifically activate MAPK. MEK1, an activator of ERK, was found in the outer layer of Hassall's corpuscles where p-ERK was expressed. MEK3, an activator of p38 kinase, was also expressed in the outer layer. MEK4 and MEK7, which are activators of JNK, were present in the entire Hassall's corpuscles. Thus, differential expression of MAPK in the thymus supports the concept that the MAPK signaling pathway controls the specificity of functional thymic responses to extracellular stimuli. Furthermore, the abundant expression of various elements of the pathway in Hassall's corpuscles suggests that the pathway is involved in thymic medullary epithelial maturation.