P-Glycoprotein conformational changes detected by antibody competition

Conformational changes accompanying P-glycoprotein (Pgp) mediated drug transport are reflected by changes in the avidity of certain monoclonal antibodies (mAbs). More of the UIC2 mAb binds to Pgp-expressing cells in the presence of substrates or modulators [Mechetner, E.B., Schott, B., Morse, S.B., Stein, W., Druley, T., Dvis, K.A., Tsuruo, T. & Roninson, I.B. (1997) Proc. Natl Acad. Sci. USA 94, 12908-12913], while the binding of other mAbs (e.g. MM12.10, MRK16, 4E3) is not conformation sensitive. Pre-staining of Pgp+ cells with UIC2 decreased the subsequent binding of MM12.10 mAb by about 30-40%, suggesting that there are Pgp molecules available for both UIC2 and MM12.10, and others accessible only for MM12.10. In the presence of certain substrates/modulators such as vinblastin, cyclosporin A or valinomycin, the MM12.10 reactivity was completely abolished by preincubation with UIC2. However, verapamil, Tween-80 and nifedipine did not influence the ratio of bound mAbs significantly. This is the first assay to our knowledge, sharply distinguishing two classes of modulators. The conformational changes accompanying the mAb competition phenomenon appear to be closely related, though not identical to those accompanying the UIC2-shift, as suggested by the simultaneous assessment of the two phenomena.

[Surgery for intractable epilepsy in children: pre- and perioperative evaluations with special reference to dipole tracing method estimated from interictal spike]

Methods of preoperative and perioperative evaluation methods for surgical treatment of intractable epilepsy in children are described. Among non-invasive diagnostic methods, EEG-video monitoring is the most fundamental. Amygdalohippocampal volume measurement by MR was useful for the differential diagnosis of mesial temporal lobe epilepsy (TLE) from lateral TLE and generalized epilepsy. The dipole tracing method with a realistic head model was useful for identification of epileptic foci from the interictal spikes of scalp EEG, when an abnormal electric source was estimated as an equivalent current dipole (ECD) in the brain of patients with organic lesion and TLE. ECD concentration ratio ranged from 70 to 90% within 20 mm around the lesion. After lesionectomy seizures disappeared in every patient. The mean distance between the centers of the ECD and epileptic focus (identified by subdural electrode recording) was 14 mm (range: 8 to 18 mm). ECDs of mesial TLE were located in the temporal base rather than mesial temporal lobe, whereas those of lateral TLE in the lateral cortex precisely. In unilateral, intermediate and bilateral TLE, 76%, 52% and 36% of ECDs were localized in the ictal onset zone respectively (p = 0.007). Electrical cortical stimulation with chronically placed intracranial electrodes was used to accurately identify eloquent areas to avoid postsurgical complications. Immediately after operation, 10 to 20% of patients showed better or deteriorated results in neuropsychological examinations, which recovered in all patients after one year. Postoperative seizures were absent in three fourths of patients. Further efforts are needed to obtain better seizure control in future.

Conformational heterogeneity of P-glycoprotein

P-glycoprotein (P-gp) acts as an active efflux mechanism for a large number of cytostatics and seems to be involved in the frequent failure of cancer chemotherapy. The molecular events of substrate recognition and transport still are not understood completely. We show here that the percentage of P-gp epitopes available for labeling with UIC2 monoclonal antibody is increased significantly after methanol permeabilization/fixation of cells. At the same time, binding of the MRK16 and 4E3 anti-P-gp antibodies is changed only moderately. Confocal microscopical images of UIC2-PE-labeled cells show that the epitopes becoming available after fixation are situated mainly in the plasma membrane. Thus, only a minority of P-gp molecules are accessible for UIC2 in the cell membrane of live cells, and methanol treatment can expose a large pool of previously plasma membrane-embedded, cryptic UIC2 epitopes. The UIC2-reactive P-gp molecules do not appear to be sequestered spatially, as suggested by the high fluorescence resonance energy transfer efficiency measured between the fluorescently labeled competing UIC2 and MRK16 antibodies, suggestive of P-gp dimerization and oligomerization on live cells.

Pancreatic volume in type 1 and type 2 diabetes mellitus

We measured pancreatic volume (PV) using helical computed tomography (CT) in 26 patients with type 1 diabetes mellitus (DM), 29 patients with type 2 DM, and 22 healthy individuals. We also evaluated the relationship between PV and the body surface area (BSA), established the pancreatic volume index (PVI) by dividing PV by BSA to correct PV for the body build, and examined its relationships with the duration of illness, serum C-peptide immunoreactivity level (CPR), and serum immunoreactive trypsin level (IRT). BSA and PV were correlated significantly (p<0.0001, r=0.645) in healthy individuals, and they were correlated also in the diabetic patients (p=0.0023, r=0.563 in type 1 DM; p=0.0346, r=0.392 in type 2 DM). PV was significantly smaller in the type 1 DM group than in the healthy group and type 2 DM group (p<0.001 for both). PVI was also significantly smaller in the type 1 DM group than in the healthy group and type 2 DM group (p<0.001 for both). PVI and IRT were significantly correlated in both DM groups (p<0.0001, r=0.732 in type 1 DM; p=0.0469, r=0.371 in type 2 DM). PVI was not correlated with the duration of illness or CPR. Helical CT was useful for the measurement of the pancreatic volume, and the pancreatic volume was reduced particularly in the patients with type 1 DM. A strong correlation was observed between PV and exocrine pancreatic function in type 1 DM, but the correlation between PV and exocrine pancreatic function was weak in type 2 DM.

Clinical study on recurrent intracranial aneurysms

The authors report 11 cases who underwent reoperations upon for recurrent aneurysms. The initial operations were performed on average 10.1 years earlier for subarachnoid hemorrhage (SAH). The patients' mean age at the first surgery was 39.7 years. The locations were 9 internal carotid (IC)-posterior communicating artery (PC) and 2 anterior communicating artery (A-com) aneurysms. A residual aneurysmal neck after the first operation was observed in 3 of 10 cases confirmed by postoperative angiography. The primitive-type PC artery was seen in 8 of 9 recurrent IC-PC aneurysms. The recurrent manifestations were SAH in 9 cases. Clipping operations were conducted in 10 and ligation of the IC artery together with extracranial-intracranial bypass in 1 large IC-PC aneurysm. The present study demonstrated two risk factors for aneurysm recurrence, namely, young age and IC-PC aneurysms with a primitive-type PC. Furthermore, direct operation for recurrent aneurysm is often embarrassing due to adhesions to the surrounding tissue as a sequela of the previous operation, hence understanding of the anatomical correlation between the old clip and the recurrent portion is important.

Radical scavenging properties of tryptophan metabolites. Estimation of their radical reactivity

Radical scavenging properties of tryptophan metabolites were estimated using their radical reactivity. Metabolites of the kynurenine and the melatonin biosynthesis pathway were mainly examined by use of a kinetical model. Their radical reactivity was determined as the reaction rate constant with a stable free radical, such as galvinoxyl; that is a phenoxy radical. The rate constants of the metabolites have a widely ranged spectrum, which can be divided into three groups. The first group (3-hydroxykynurenine, 3-hydroxyanthranilic acid, and indole-3-pyruvic acid) is more reactive than alpha-tocopherol; the reactivity of the second group (xanthurenic acid, serotonin, N-acetylserotonin) is similar to that of butylated hydroxytoluene (BHT); the third group (kynurenic acid, melatonin, and other ones) is less reactive than BHT.

Combined effects of ethanol and garlic on hepatic ethanol metabolism in mice

The combined effects of ethanol and components in fresh garlic on ethanol metabolism were investigated in the livers of mice. Male, 11-wk-old C3H/HeNCrj mice were intragastrically administered 2 g ethanol/kg body weight after being administered fresh garlic juice for 8 d (garlic group), and changes in the concentrations of ethanol, acetaldehyde and acetate in the serum, and changes in the activity of hepatic enzymes related to ethanol metabolism in mice were examined. The increases in the concentrations of acetaldehyde and acetate in the serum after ethanol administration tended to be diminished following garlic administration. The microsomal ethanol-oxidizing system (MEOS) in the livers of the garlic groups was significantly lower than that of the control microsomes at 2 h after ethanol administration. It therefore seems that the decrease of MEOS in hepatic microsomes caused a smaller increase in the acetaldehyde concentration in the serum of the garlic groups because cytosolic alcohol dehydrogenase showed no significant difference between the control and garlic groups. After ethanol administration, the content of cytochrome P-450 in the hepatic microsomes of the control groups increased, while that of the garlic groups did not change although cytochrome P-450 (CYP) 2E1 and 1A2 in the hepatic microsomes of the garlic groups increased. These results indicate that the induction of isozymes of cytochrome P-450 other than CYP 2E1 and 1A2 was inhibited following garlic administration. Cytosolic high Km and total aldehyde dehydrogenase (AIDH) in the liver of the garlic groups tended to be lower than those activities of the control groups at 1 and 2 h after ethanol administration. It therefore seems that the decreases of AIDH in the hepatic cytosols diminished the increase of acetate in the serum of the garlic groups after ethanol administration. These results suggest that the ethanol metabolism in the mouse liver is controlled by components in fresh garlic juice.

Characterization of an apparently conserved epitope in E- and P-selectin identified by dual-specific monoclonal antibodies

E- and P-selectin recognize a wide and overlapping range of oligosaccharide ligands including sialyl-Lewis X (sLeX) through their highly homologous C-type lectin domains. We report that an epitope apparently conserved between E- and P-selectin is functionally involved in ligand recognition although distantly located from the conventional carbohydrate binding site. We found that a previously established anti-E-selectin monoclonal antibody (mAb), 1.2B6, is cross-reactive with P-selectin, and that the 1.2B6 epitope is in the C-type lectin domain and identical to or overlapping with an epitope recognized by other independently established anti-E- and P-selectin dual-specific mAb. The epitope has been mapped by others to a region distant from the previously identified carbohydrate binding site of E-selectin in its three-dimensional structure. Nevertheless, it is of note that all dual-specific mAb, including 1.2B6, inhibited E- or P-selectin-mediated cell adhesion and also binding to sLeX. Engagement of the apparently conserved epitope by the dual-specific mAb may lead to inhibition of the ligand binding ability of E- and P-selectin by a previously uncharacterized mechanism(s) rather than by direct inhibition of sLeX binding to the hitherto identified ligand binding site.

4-Phenylthiazole derivatives inhibit IL-6 secretion in osteoblastic cells and suppress bone weight loss in ovariectomized mice

A series of 4-phenylthiazole derivatives were synthesized and tested their inhibitory effect on the interleukin-6 secretion stimulated by PTH in osteoblastic cells. SCRC2941-18, 2-amino-4-(4-chlorophenyl)-5-methylthiazole, was found to be the most potent inhibitor in the derivatives. Furthermore, SCRC2941-18 significantly suppressed the bone weight loss in the ovariectomized mice, an osteoporosis model.

Histopathologic studies of colorectal postendoscopic resection sites: "skipping electrothermal injury" associated with endoscopic resection procedures

To elucidate the pathologic changes due to endoscopic resection (ER), 32 post-ER sites in 24 surgically removed colorectal specimens and the previous ER specimens were examined. The depth of all the previous ER specimens was restricted to the submucosa, and all post-ER sites showed submucosal stromal changes of various degrees. Fourteen sites (43.8%) showed muscular or serosal changes. One of these lesions was considered to be a reaction to a tattoo agent, but all the other lesions were considered to represent skipping electrothermal injury caused by electrical current passing through the colorectal wall. The lesions consisted of muscular depletion in the inner layer of the muscularis propria (12 sites, 37.5%), hemorrhage or fibrosis between the inner and outer layers of the muscularis propria (3 sites, 9.4%), and serosal changes (10 sites, 31.3%). These skip regions would be vulnerable to electrical current. These findings suggest that asymptomatic electrothermal injury associated with ER is frequent. Statistically, the electrothermal injury appeared to be related to the size of the previous ER specimens. However. these results also reveal that the ER of tissues <10 mm can cause electrothermal injury and can result in full-thickness necrosis.

Effect of chronic administration of alcoholic beverages and seasoning containing alcohol on hepatic ethanol metabolism in mice

Five-week-old male mice, C3H/HeNCrj (C3H/He), were given a 5% (v/v) ethanol solution, commercial alcoholic beverages (Japanese sake (sake) or red wine) or a Japanese seasoning (mirin [containing ethanol and a large amount of glucose]) ad libitum for 45 d, and were then examined for changes in the hepatic enzymes related to ethanol metabolism 2 h after oral administration of 5 g of ethanol/kg body weight. The specific activity of aniline hydroxylase (ANH) in the hepatic microsome increased significantly in all groups chronically administered ethanol solution, sake, red wine or mirin, and the greatest increase was in the hepatic microsome of mirin-administered mice. The cytochrome P-450 (CYP) 2E1 increased in the hepatic microsome of the mice administered ethanol solution, red wine or mirin where accompanied by high ANH activity. The immunoreactive band for CYP1A1 showed high specificity in the microsome of mice given sake, red wine or mirin. It was assumed that CYP1A1 was induced by unknown component(s) other than ethanol in these solutions. In the cytosolic fraction, following the chronic administration of sake and mirin, the total aldehyde dehydrogenase (A1DH) activity with high-Km decreased significantly. In the mitochondrial fraction, the activity of high-Km A1DH increased significantly in the mirin-administered mice which drank a large amount of ethanol, whereas that in the red wine-administered group tended to decrease. These results indicate that the enzyme activities related to the oxidation of both ethanol and acetaldehyde in the cytosolic, mitochondrial and microsomal fractions of the liver were affected by either the action of ethanol or its interaction with other constituents of sake, red wine and mirin.

Intracellular pH does not affect drug extrusion by P-glycoprotein

The intracellular pH (pH(i)) of cells exhibiting multidrug resistance (MDR) related to the expression of the P-glycoprotein (Pgp) is often more alkaline than that of the parental cells, as also observed for the KB-V1/KB-3-1 system in this paper. The possible role of an elevated pH(i) in Pgp-related MDR has been investigated by shifting back the pH(i) of the MDR+ cells to a more acidic value using the mobile proton ionophore carbonylcyanide m-chlorophenylhydrazone (CCCP). The influence of CCCP-evoked delta pH(i) on relative daunorubicin (DNR) accumulation was similar in the case of several Pgp positive and negative cell lines, in view of flow cytometric and radioactive drug accumulation studies and measuring DNR levels in the medium in a flow-through system. Our data argue against a significant effect of pH(i) on Pgp pumping efficiency. However, an indirect connection between pH(i) regulation and the MDR phenotype is suggested by the fact that acidification of the external medium in the presence of verpamil could be observed exclusively in MDR+ cells.

Reversal of multidrug resistance by valinomycin is overcome by CCCP

Reversal of P-glycoprotein-mediated multidrug resistance by valinomycin is overcome by the proton ionophore, CCCP. This effect, a complete suppression of the 5- to 10-fold valinomycin-induced reversal ("re-reversal"), exhibits a sharp extracellular potassium concentration ([K+(0)]) dependence. It is observed at [K+(0)] > 2-4 mM and not at [K+(0)] greater than or equal to 2 mM, in the case of the fluorescent substrates rhodamine 123 and daunorubicin. The fact that "re-reversal" is detected only for the combination of CCCP with valinomycin raises the possibility that a direct interaction between these ionophores may explain the phenomenon. We show spectroscopic evidence of such an interaction, with a [K+(0)]-dependence similar to that of the "re-reversal." These data suggest that the reversal of P-glycoprotein activity by valinomycin can be compromised by anionic compounds such as CCCP due to complex formation. More generally, molecular interactions involving P-glycoprotein substrates or reversing agents may significantly affect drug accumulation in multidrug resistant cells.

Changes in hepatic enzyme activities related to ethanol metabolism in mice following chronic ethanol administration

Male mice of three strains, C57BL, DBA and C3H/He, were fed on commercial food with 10% (v/v) ethanol solution as drinking liquid ad libitum for eighty days, and the changes in the activities of enzymes in the metabolic pathway of ethanol in the liver were examined. C57BL and C3H/He mice showed a preference for drinking the 10% (v/v) ethanol solution, while DBA mice did not. The ethanol intake g/g of body weight of C3H/He mice showed the highest value among all three strains and that of C57BL mice tended to show higher value than that of DBA mice. The liver weights of C57BL and C3H/He mice increased significantly following chronic ethanol administration, but that of DBA did not. The cytosolic enzyme alcohol dehydrogenase (ADH) showed no changes in any of the strains following chronic ethanol administration. The microsomal ethanol-oxidizing system (MEOS) of C57BL mice exhibited approximately 2-fold higher activity compared to that of DBA and C3H/He mice but did not increase in any strain following chronic ethanol administration. However, the microsomal aniline hydroxylase activity in the liver increased significantly in C57BL and C3H/He mice following chronic administration of ethanol. The microsomal cytochrome P-450 content also tended to slightly increase in the same strains of mice. It seemed that cytochrome P-450IIE1 was induced in the liver microsomes of these strains. Total aldehyde dehydrogenase (ALDH) activities together with high-Km ALDH activity increased markedly in the microsomes of C57BL mice and tended to increase in C3H/He mice, while it did not change in DBA mice following chronic ethanol administration. In the mitochondria of C57BL, total ALDH activities increased slightly and high-Km ALDH activities tended to increase. These mitochondrial ALDH activities of C3H/He and DBA mice tended to increase following chronic ethanol administration. The cytosolic ALDH activity showed no changes in any strain of mice following chronic ethanol administration. It seemed that in the microsomes, the activities of enzymes related to oxidation of ethanol increased in C57BL and C3H/He mice, which tended to consume a large amount of ethanol, and did not in DBA mice which tended to consume a small amount of it. It seemed that the increases in activities of enzymes related to oxidation of acetaldehyde in the microsomes and in the mitochondria were responsible for the strain difference.

Effects of intravenous nitroglycerin combined with dopamine on intracranial pressure and cerebral arteriovenous oxygen difference in patients with acute subarachnoid haemorrhage

The effects of intravenous nitroglycerin (NTG) combined with dopamine on intracranial pressure (ICP) and cerebral arteriovenous oxygen difference (AVDO2) were studied in 11 patients with acute subarachnoid haemorrhage (SAH). The study was performed on Days 1 to 3 of SAH after aneurysmal clipping. Treatment consisted of an intravenous drip infusion of NTG in increasing incremental doses of 0.5, 1.0, 1.5, 2.0, and 2.5 micrograms/kg/min at one-hour intervals. Dopamine (5 to 10 micrograms/kg/min) was also given concurrently to maintain systemic blood pressure. ICP values before NTG administration ranged from 7 to 24 mmHg (mean. 11.91 +/- 5.30 mmHg). ICP began to increase immediately after the administration of NTG 0.5 microgram/kg/min and peaked at 14.64 +/- 5.93 mmHg 10 minutes after onset of infusion. Thereafter, ICP gradually returned to pretreatment levels. Increasing the dose of NTG failed to induce further significant rises in ICP. Mean AVDO2 before NTG administration was 4.69 +/- 0.62 ml/dl. This parameter showed no significant change during NTG infusion, although cerebral perfusion pressure decreased to between 75% to 94% of the control value after NTG administration. These results indicate that continuous NTG infusion combined with dopamine does not have adverse effects on ICP (the ICP increase is minimal and transient) and may even have beneficial effects on CBF in patients with acute SAH.

A study on urine cotinine for the evaluation of smoking cessation

Two branch offices of enterprise T in the same city engaged in service and sales were selected at random for this study on the evaluation of smoking cessation education using the urine cotinine concentration (U-Cot) measured by ion pair reversed-phase high performance liquid chromatography (IP-R-HPLC). Branch A conducted a smoking cessation education program; branch B did not. By comparison of the results obtained from questionnaires and U-Cot analyses at both the offices, we investigated the validity of evaluation by U-Cot. The results were as follows: I. Smokers 1. At branch A, a self-reported 20-year-old female non-smoker was confirmed to smoke about 5 cigarettes per day by her high concentration (292.8) of U-Cot at pre-education. 2. At branch A, the self-reported average number of cigarettes smoked daily (ANCSD) at 6 months post-education showed a significant decrease in comparison with that at pre-education. 3. At branch A, U-Cot at post-education showed a significant decrease in comparison with those at 2 weeks, 2 months, and 6 months pre-education in descending order. 4. Two male subjects who were strongly suspected to have submitted a false number of cigarettes smoked prior to urine sampling (NCSPU)/ANCSD self-reports at 6 months post-education were confirmed to have done so by the U-Cot values at the fourth period, which were in excess of 500, and the discrepancy between the ratio ([value at post-education in 6 months] divided by [value at pre-education]) of U-Cot (1.52, 1.47, respectively) and that of NCSPU/ANCSD, (0.00)/0.00). 5. At branch A, discrepancies between the success rate of quitting smoking in self-reported NCSPU/ANCSD at 6 months (17.0%) and in U-Cot (12.2%) were observed. At branch B, no such discrepancies were observed. 6. At branch A, office workers at 6 months post-education who had, but not those who had not, previously considered the health damage caused by smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. At branch B, no such differences were observed. 7. At branch A, office workers at 6 months post-education who had previously considered quitting smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. Those who had not previously considered quitting showed a significant decrease in ANCSD, but not in NCSPU or U-Cot.(ABSTRACT TRUNCATED AT 400 WORDS)

Dissecting thoracic aorta and fusiform aneurysm of the abdominal aorta

A 59-year-old woman with dissection of the thoracic aorta and a fusiform aneurysm of the abdominal aorta without evidence of Marfan's syndrome underwent aneurysmorrhaphy with a bifurcated expanded polytetrafluoroethylene graft. Histological specimens of the aneurysmal wall revealed the presence of idiopathic cystic medial necrosis. As typical findings of idiopathic cystic medial necrosis in the aortic wall are very rare except in cases of Marfan's syndrome, the present case is reported and the implications of this condition are discussed.

Moment of inertia of whole body using an oscillating table in adolescent boys

This study measured the moment of inertia of the body using the oscillating table method, and saw how it is affected by age and body size. One hundred and seventeen subjects of junior and senior high school boys of ages 13-18 participated in this study. Moment of inertia was measured in two postures of supine (Imx) and recumbent (Imy) positions. Both Imx and Imy account for the range from 5.6 to 14.0 kg m2 and 4.2 to 13.5 kg m2, respectively, and correlate linearly to body height (Ht) and body weight (W). The values of Imy/Imx becomes 93.6 and 95.2% independent of age and body size. The difference between Imx and Imy might be affected by projection areas on the frontal from the sagittal area of the body. The multiple regression analysis of Ht2 and W with regard to Im was performed to obtain the following multiple regression equations: Imx = 3.44 Ht2 + 0.144 W - 8.04 (R = 0.973), Imy = 3.52 Ht2 + 0.125 W - 7.78 (R = 0.972). When Imx and Imy were estimated using these equations, the standard deviation of error which calculates the percent differences between the estimated and measured values amounted to +/- 5% in Imx and Imy. The results suggest that, with Japanese boys, there is a relationship between the postures and body size (height or weight), independent of age.

Contractile and morphological impairment of cultured fetal mouse myocytes induced by oxygen radicals and oxidants. Correlation with intracellular Ca2+ concentration

There is evidence that reperfusion injury of cardiac tissue may be caused by the generation of oxygen-derived free radicals and oxidants and by the induction of intracellular calcium overload, although the relation between these two mechanisms of injury is uncertain. In addition, the relation between the types of cellular injury and specific active species is unclear. In an attempt to resolve these problems, we investigated the effects of oxygen radicals and oxidants, which are purportedly generated during reperfusion after prolonged ischemia, and various antioxidants on contractility and morphology of cultured fetal mouse cardiac myocytes. Xanthine oxidase in the presence of xanthine, H2O2, HOCl, and NH2Cl induced cessation of spontaneous beating followed by cessation of electrical stimulation-elicited beating but did not induce an increase in [Ca2+]i. After prolonged incubation with xanthine oxidase + xanthine and H2O2, the cardiac myocytes showed morphological degeneration (at least 80% of the cells developed hypercontraction) with a concomitant increase in [Ca2+]i. These observations suggest that contractile impairment does not result in an increase of [Ca2+]i, but hypercontraction does. Catalase, but not superoxide dismutase, protected the cultured cardiac myocytes against xanthine oxidase + xanthine- and H2O2-induced contractile and morphological impairment. In the light of this observation, we hypothesize that the superoxide anion is not responsible for these types of impairment. Addition of dimethylthiourea (an .OH scavenger) and intracellular preloading with deferoxamine (an iron chelator) protected the myocytes against H2O2-induced contractile and morphological damage, but intracellular preloading with iron enhanced it. These observations led us to hypothesize that intracellularly generated .OH may be a mediator of H2O2-induced injury to cultured cardiac myocytes. In addition, we observed that H2O2 itself induced cessation of spontaneous but not electrical stimulation-elicited beating.

Suprasellar embryonal carcinoma which developed ten years after local radiation therapy for pineal germinoma

We recently encountered a case of suprasellar embryonal carcinoma which developed 10 years after local radiation therapy for pineal germinoma. This 29-year-old male was admitted because of abnormal behavior, disturbed consciousness, and increased intracranial pressure. Computed tomography and magnetic resonance imaging disclosed a tumor spreading from the suprasellar region to the third ventricle and the anterior horn of the left lateral ventricle, accompanied by fresh hemorrhage within the tumor. He underwent subtotal removal of the tumor, followed by chemotherapy with cisplatin and etoposide. The tumor was histologically rated as embryonal carcinoma with differentiation into yolk sac tumor and choriocarcinoma.

Anaplastic astrocytoma of an oncocytic type occurring in the cerebellar vermis in Pierre Robin syndrome--case report

A 44-year-old male with Pierre Robin syndrome and funnel chest was diagnosed with a tumor of the cerebellar vermis and spontaneous pneumothorax. He received tube thoracostomy for pneumothorax and ventriculoperitoneal shunt for hydrocephalus, followed by radiological examination, subtotal removal of the tumor, pneumonorrhaphy, and chemoradiotherapy. Light microscopy of the tumor sample revealed marked pleomorphism of the tumor cells and numerous giant cells, without mitotic figures. Microcystic changes due to vasogenic edema were also evident throughout the tumor. Electron microscopy showed more than 50% of all tumor cells to be oncocytes, with numerous mitochondria in the cytoplasm. The tumor was diagnosed as anaplastic astrocytoma of an oncocytic type.

Synthetic studies of carbapenem and penem antibiotics. II. Synthesis of 3-acetyl-2-azetidinones by (2 + 2) cycloaddition of diketene and Schiff bases

It was found that (2 + 2) cycloaddition reaction of diketene with Schiff bases was effectively promoted by imidazole as a catalyst to afford 3-acetyl-2-azetidinone derivatives 4. As an application of this new method, a practical asymmetric synthesis of 4 and its conversion into (3S,4S)-4-carboxy-1-(di-p-anisylmethyl)-3-[(R)-1-hydroxyethyl]-2- azetidinone, which is a key intermediate for the synthesis of carbapenem and penem antibiotics, were accomplished.

Secretory meningioma with elevated serum carcinoembryonic antigen level

We recently encountered a 68-year-old woman with right sphenoid wing meningioma of the secretory type accompanied by an elevated serum carcinoembryonic antigen level. This case was neuroradiologically characterized by marked brain edema. Histologically, the lesion was rated as having meningothelial components and was rich in blood vessels and pseudopsammoma bodies. Carcinoembryonic antigen, epithelial membrane antigen, keratin, and cytokeratin were immunohistochemically detected in the pseudopsammoma bodies and the cells producing these bodies.

Three-dimensional structure of a mutant ribonuclease T1 (Y45W) complexed with non-cognizable ribonucleotide, 2'AMP, and its comparison with a specific complex with 2'GMP

The crystal structure of a mutant ribonuclease T1 (Y45W) complexed with a non-cognizable ribonucleotide, 2'AMP, has been determined and refined to an R-factor of 0.159 using X-ray diffraction data at 1.7 A resolution. A specific complex of the enzyme with 2'GMP was also determined and refined to an R-factor of 0.173 at 1.9 A resolution. The adenine base of 2'AMP was found at a base-binding site that is far apart from the guanine recognition site, where the guanine base of 2'GMP binds. The binding of the adenine base is mediated by a single hydrogen bond and stacking interaction of the base with the imidazole ring of His92. The mode of stacking of the adenine base with His92 is similar to the stacking of the guanine base observed in complexes of ribonuclease T1 with guanylyl-2',5'-guanosine, reported by Koepke et al., and two guanosine bases, reported by Lenz et al., and in the complex of barnase with d(GpC), reported by Baudet & Janin. These observations suggest that the site is non-specific for base binding. The phosphate group of 2'AMP is tightly locked at the catalytic site with seven hydrogen bonds to the enzyme in a similar manner to that of 2'GMP. In addition, two hydrogen bonds are formed between the sugar moiety of 2'AMP and the enzyme. The 2'AMP molecule adopts the anti conformation of the glycosidic bond and C-3'-exo sugar pucker, whereas 2'GMP is in the syn conformation with C-3'-endo-C'-2'-exo pucker. The mutation enhances the binding of 2'GMP with conformational changes of the sugar ring and displacement of the phosphate group towards the interior of the catalytic site from the corresponding position in the wild-type enzyme complex. Comparison of two crystal structures obtained provides a solution to the problem that non-cognizable nucleotides exhibit unexpectedly strong binding to the enzyme, compared with high specificity in nucleolytic activity. The results indicate that the discrimination of the guanine base from the other nucleotide bases at the guanine recognition site is more effective than that estimated from nucleotide-binding experiments so far.