[Report on Options for the Control of Influenza Virus IV].
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Biomedical subjects
Publications and source records attributed to K Hara.
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Increased expression of heat shock protein 70 (HSP70) in the brain has been extensively documented in association with a variety of insults, including ischemia, and is suggested to play a role in cell survival and recovery after ischemic injury. To more directly assess the protective role of HSP70 during ischemic brain damage, we used transgenic mice overexpressing the rat HSP70 (HSP70tg mice). In contrast to wild-type (wt) littermates, high levels of HSP70 messenger RNA and protein were detected in brains of HSP70tg mice under normal conditions, and immunohistochemical analysis revealed primarily neuronal expression of HSP70. Heterozygous HSP70tg mice and their wt littermates were subjected to permanent focal cerebral ischemia by intraluminal blockade of the middle cerebral artery. Cerebral infarction after 6 hours of ischemia, as evaluated by Nissl staining, was significantly less in HSP70tg mice compared with wt mice. This reduction in infarction volume in HSP70tg mice was not attributable to an altered cardiovascular anatomy or to initial differences in body temperature or hemodynamic parameters. The HSP70tg mice were still protected against cerebral infarction 24 hours after permanent focal ischemia. The data suggest that HSP70 can markedly protect the brain against ischemic damage and that approaches aimed at inducing HSP70 may lead to new therapeutic interventions in cerebrovascular injuries.
A 78-year-old woman with renal cell carcinoma and pulmonary metastasis presented with reversible cardiomyopathy induced by gamma(gamma)-interferon. She was treated with gamma-interferon twice a week since November 1996. She presented with severe acute congestive heart failure and gamma-interferon was immediately discontinued in December 1997. Left ventricular fractional shortening was 38% before admission, 12% on admission, and improved to 31% by 40 days after discontinuation of interferon together with administration of diuretics and angiotensin converting enzyme inhibitor. We restarted the same gamma-interferon regimen because it was effective against renal cell carcinoma after 47 days. She has remained well with no significant changes of cardiac function or renal cell carcinoma for almost one year.
Echocardiographic follow-up for 16 years in an asymptomatic patient with mitral stenosis showed very slow growth of a mass attached to the mitral valve. The tumor doubling time was estimated to be 3.6 years. Surgical excision of the mass was performed when the patient eventually developed dyspnea on exertion, and histopathological examination revealed papillary fibroelastoma. Echocardiographic follow-up and anti-coagulation may be sufficient treatment for asymptomatic patients with papillary fibroelastoma.
A 28 year-old man complaining of intermittent headaches for a month following an episode of general convulsions was admitted to the Department of Neurosurgery of our hospital. His brain CT scan showed a well-enhanced mass growing symmetrically along the anterior cerebral falx in a manner compatible with meningioma. Nothing abnormal was detected in chest radiography on admission. Histopathological examination of the mass after partial resection revealed multiple epithelioid cell granulomas with giant cells indicating sarcoidosis. After 4 weeks of treatment with oral prednisolone 30 mg/day, bronchoalveolar lavage was performed in our department. In the lavage fluid, both the total cell count and the percentage of lymphocytes were elevated. The lung specimens obtained by transbronchial biopsy also showed epithelioid cell granulomas. CNS sarcoidosis is reportedly usually observed in the vicinity of the hypothalamus with other organ involvement. In the present case, differential diagnosis of sarcoidosis from meningioma was difficult because the solitary lesion was growing along the anterior cerebral falx without radiographic evidence of bilateral hilar lymphadenopathy.
Investigation in the present case began with a high serum Fe concentration. The routine method for determining serum Fe concentration in our hospital is direct photoscopic assay. When we assayed serum Fe concentration by a deproteinization method, it showed a higher value. We also measured serum ferritin concentration, and suspected that high ferritin interfered with serum Fe concentration. We checked the dose-dependent effect of ferritin on serum Fe determination. The present case, a 64-year-old female, showed a reduction of Plt count, and an elevation of LDH, CRP and so on, meeting most of the criteria for hemophagocytosis syndrome. Bone marrow smears revealed phagocytosis of blood cells. The present case had been followed for rheumatoid arthritis and medicated with oral iron pills. In her liver and spleen, high amounts of Fe had accumulated, and excessive Fe was being released into the blood by any trigger, such as infection, stress, cytokine activation, and/or HPS.
Two operating rooms were newly constructed to facilitate the increasing need of surgical services in our university hospital. After a half year of use, the oxygen delivery was suddenly blocked in one of them. Fortunately, the serious incident did not occur because an anesthesiologist identified the blockage of oxygen flow when he checked the anesthesia machine prior to the patient arriving in the operating room. Upon investigation we found the structural defects in ceiling column of that operating room. The pipe containing nitrous oxide and its structural support touched the valve of oxygen supply. It appears that the valve was gradually turned off by this contact while the ceiling column was moved up and down. Once this structural defect had been repaired, there was no longer any incident of the accidental blockage of oxygen to the operating room.
We describe a 55-year-old woman with acute lymphoblastic leukemia (ALL) in the first remission who underwent nonmyeloablative stem cell transplantation with conditioning consisting of low-dose total body irradiation and postgrafting cyclosporine and mycophenolate mofetil. Myelosuppression was mild, but on day 28 her bone marrow showed 8.8% lymphoblasts. We withdrew the cyclosporine, but the patient developed grade 2 acute GVHD and eosinophilia. The proportion of bone marrow lymphoblasts decreased transiently to 1.0% on day 40, but later increased again and the patient died on day 85. Application of this approach to patients with ALL needs to be examined on a large scale.
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In Kagawa Prefecture, a perinatal management system using the optical medical card and the information network has been introduced since October 1998. Four hospitals(Kagawa Medical University, Sakaide Municipal Hospital, Uchinomi Town Hospital and Tsuda Prefectural Hospital) are connected with each other through the health information network(Kagawa Health and Welfare Information Network) organized by Kagawa Prefecture. (http://www.hw.kagawa-swc.or.jp/net/) Patients' clinical data are described on the optical card based on the "standard format of the Japan Association of Obstetricians and Gynecologists(JAOG). (http://www.jaog.or.jp/JAPANESE/MEMBERS/JOUHOU/H10/index.htm). Clinical information including the fetal heart rate(FHR) and sonography (JPG) can be easily transmitted through this network(on line). Without the network, patient data can also be transmitted using the optical card(off line). There are still many technical and social problems to be solved in the future, research into the use of medical information network should be continued.
There are three conserved phosphorylation sites in protein kinase C (PKC) isotypes that have been termed priming sites and play an important role in PKC function. The requirements and pathways involved in novel (nPKC) phosphorylation have been investigated here. The evidence presented for nPKCdelta shows that there are two independent kinase pathways that act upon the activation loop (Thr-505) and a C-terminal hydrophobic site (Ser-662) and that the phosphorylation of the Ser-662 site is protected from dephosphorylation by the Thr-505 phosphorylation. Both phosphorylations require C1 domain-dependent allosteric activation of PKC. The third site (Ser-643) appears to be an autophosphorylation site. The serum-dependent phosphorylation of the Thr-505 and Ser-662 sites increases nPKCdelta activity up to 80-fold. Phosphorylation at the Ser-662 site is independently controlled by a pathway involving mammalian TOR (mTOR) because the rapamycin-induced block of its phosphorylation is overcome by co-expression of a rapamycin-resistant mutant of mTOR. Consistent with this role of mTOR, amino acid deprivation selectively inhibits the serum-induced phosphorylation of the Ser-662 site in nPKCdelta. It is established that nPKCepsilon behaves in a manner similar to nPKCdelta with respect to phosphorylation at its C-terminal hydrophobic site, Ser-729. The results define the regulatory inputs to nPKCdelta and nPKCepsilon and establish these PKC isotypes downstream of mTOR and on an amino acid sensing pathway. The multiple signals integrated in PKC are discussed.
p70 S6 kinase alpha (p70alpha) is activated in vivo through a multisite phosphorylation in response to mitogens if a sufficient supply of amino acids is available or to high concentrations of amino acids per se. The immunosuppressant drug rapamycin inhibits p70alpha activation in a manner that can be overcome by coexpression of p70alpha with a rapamycin-resistant mutant of the mammalian target of rapamycin (mTOR) but only if the mTOR kinase domain is intact. We report here that a mammalian recombinant p70alpha polypeptide, extracted in an inactive form from rapamycin-treated cells, can be directly phosphorylated by the mTOR kinase in vitro predominantly at the rapamycin-sensitive site Thr-412. mTOR-catalyzed p70alpha phosphorylation in vitro is accompanied by a substantial restoration in p70alpha kinase activity toward its physiologic substrate, the 40 S ribosomal protein S6. Moreover, sequential phosphorylation of p70alpha by mTOR and 3-phosphoinositide-dependent protein kinase 1 in vitro resulted in a synergistic stimulation of p70alpha activity to levels similar to that attained by serum stimulation in vivo. These results indicate that mTOR is likely to function as a direct activator of p70 in vivo, although the relative contribution of mTOR-catalyzed p70 phosphorylation in each of the many circumstances that engender p70 activation remains to be defined.
A liquid chromatography-electrospray ionization tandem mass spectrometric method was developed for the simultaneous determination of losartan and its major active metabolite, EXP-3174, in human plasma. The two analytes and the internal standard (DuP-167) were extracted from plasma under acidic conditions by using solid-phase extraction cartridges containing a sorbent of copolymer, poly(divinylbenzene-co-N-vinylpyrrolidone). The analytes were separated by LC equipped with a reversed-phase C18 column, and introduced into the mass spectrometer via the electrospray ion source with pneumatically-assisted nebulization. For LC-MS-MS samples, an isocratic mobile phase consisting of [0.1% triethylamine-0.1% acetic acid (pH 7.1)]-acetonitorile (65:35, v/v) was used, and the assay was monitored for the negative fragment ions of the analytes. The method demonstrated linearity from 1 to 1000 ng/ml for both losartan and EXP-3174. The limit of quantification for both compounds in plasma was 1 ng/ml. This assay method may be useful for the measurement of levels of the two compounds in clinical studies of losartan.
Homogeneous preparations of alpha(3)beta(3)gamma complexes with one, two or three non-competent non-catalytic site(s) were performed as described [Amano, Hisabori, Muneyuki, and Yoshida (1996) J. Biol. Chem. 271, 18128-18133] and their properties were compared with those of the wild-type complex. The ATPase activity of the complex with three non-competent non-catalytic sites decayed rapidly to an inactivated state, as reported previously [Matsui, Muneyuki, Honda, Allison, Dou, and Yoshida (1997) J. Biol. Chem. 272, 8215-8221]. In contrast, the complex with one or two non-competent non-catalytic sites displayed a substantial steady-state phase activity depending on the number of non-competent non-catalytic sites in the complex. This result indicates that one competent non-catalytic site can maintain the continuous catalytic turnover of the enzyme and can potentially relieve all three catalytic sites from inhibition by MgADP(-). Furthermore, the results suggest that the interaction between three non-catalytic sites might not be as strong as that between catalytic sites, which are all strictly required for a continuous catalytic turnover.
CD98, which forms a heterodimer of relative molecular mass (M(r)) 125, 000, was originally identified as an early T cell activation antigen. It consists of a heavy chain of M(r) 85,000 that bears the CD98 epitope and a light chain of M(r) 40, 000. CD98 is strongly expressed on the surface of activated lymphocytes and various tumor cells irrespective of tissue origins. To investigate the participation of CD98 in cellular proliferation and malignant transformation, we established and characterized human CD98-transfected NIH3T3 clones. Although the doubling times of the control cells and CD98-transfected clones were almost the same, CD98-transfected clones grew to a higher saturation density than control cells. Effciency of colony formation in soft agar was augmented in CD98-transfected clones, and this augmentation was significantly reduced by anti-human CD98 mAb. Furthermore, CD98-transfected clones developed tumors in athymic mice. These results indicated that overexpression of CD98 participates in the process of malignant transformation, suggesting that CD98 has oncogenic potential.
Cerebral ischemia induces immediate early genes such as c-fos and stress genes such as hsp70. In this study, the spatial relationships between c-fos and hsp70 mRNA expression and changes detectable with diffusion and perfusion magnetic resonance (MR) imaging were examined. The middle cerebral artery (MCA) of young adult rats was occluded for 30 or 60 min. Diffusion MR (D-MR) images were acquired continuously during the ischemic period and dysprosium-contrast perfusion (P-MR) images were acquired at the end of the ischemic period. C-fos and hsp70 mRNA expression were examined with in situ hybridization. The most significant finding of this work was that for both durations of ischemia, c-fos induction was observed in cortical and sub-cortical regions exhibiting a transient reduction in the apparent diffusion coefficient of water (ADC). Transients which occurred on a time scale of 3 min may have been caused by spreading depression. Those occurring on a 10-min time scale may have been caused by an initial reduction in blood flow with occlusion that was followed by an ischemia-induced increase in collateral blood flow. P-MR imaging showed that perfusion in c-fos positive regions was higher than in regions with persistently reduced ADC. Hsp70 induction did not correlate with transient ADC reduction. It was induced in the MCA territory in regions showing persistent ADC changes, with induction being greatest at the periphery of these regions. It was also induced in regions that exhibited both spontaneous reversal of the diffusion changes and decreased perfusion.
Headspace solid-phase microextraction (HS-SPME) was utilized for the determination of three dichlorobenzene isomers (DCBs) in human blood. In the headspace at 30 degrees C, DCBs were absorbed for 15 min by a 100-micron polydimethylsiloxane (PDMS) fiber. They were then analyzed by capillary column gas chromatography-mass spectrometry (GC-MS). By setting the initial column oven temperature at 20 degrees C, the three isomers were resolved at the baseline level. p-Xylene-d10 was used as the internal standard (I.S.). For quantitation, the molecular ion at m/z 146 for each isomer and the molecular ion at m/z 116 for I.S. were selected. For day-to-day precision, relative standard deviations in the range 3.2-10.7% were found at blood concentrations of 1.0 and 10 micrograms/ml. Each compound was detectable at a level of at least 0.02 microgram per 1 g of whole blood (by full mass scanning). HS-SPME-GC-MS, when performed at relatively low temperatures, was found to be feasible in toxicological laboratories. Using this method, the plasma levels of one patient who had drunk a pesticide-like material were measured.