[Usefulness of selective cerebral angiography by transradial approach]

Transradial angiography has recently emerged as an alternative to the transfemoral or transbrachial approach, especially for coronary procedures. However, there have been few studies on cerebral angiography using the transradial approach. The purpose of this study was to assess the outcomes, complications, and limitations of selective cerebral angiography via the transradial approach. Selective cerebral angiography by the right transradial approach using 100-cm-long 4-F catheters was performed in 83 patients. Using five types of catheters, the success rates of selective catheterization to the right vertebral artery, right common carotid artery, left common carotid artery, and left vertebral artery were 40/44 (91%), 68/68 (100%), 62/62 (100%), and 14/25 (56%), respectively. Puncture failed in one patient, and a guidewire could not be introduced beyond the radial artery loop in one patient. Radial artery spasm occurred in one patient, but was relieved immediately after nitroglycerin injection through the sheath with side holes. Subcutaneous bleeding occurred in six patients, but no obvious hematomas were noted. Occlusion or stenosis of the radial artery occurred in five patients, but no ischemic symptoms were observed in any of the cases. This study suggested that selective cerebral angiography can be performed safely using the transradial approach.

Beta-1 (10-20 Hz) cortical oscillations observed in the human medial temporal lobe

During wakefulness, signals from subdural electrodes attached to the basal and medial temporal lobes of adult human epilepsy patients revealed a rhythmic oscillation in the beta-1 frequency range (10-20 Hz). This activity was more prominent in the medial than in the basal temporal cortex. We also observed simultaneous oscillations in alpha frequency activity in the medial and the basal temporal cortices. In an eyes-open condition, the alpha oscillation was attenuated, while the beta-1 oscillation in the medial temporal lobe was not. This is the first report that the beta-1 oscillation is present in the human medial temporal lobe. Since we recorded this activity from within the limbic system, beta-1 activity may be an analog of the hippocampal rhythmic slow activity observed in some animals.

Hyperglycemia rapidly suppresses flow-mediated endothelium-dependent vasodilation of brachial artery

OBJECTIVES

We examined whether endothelial dysfunction occurs when acute hyperglycemia is induced by oral glucose loading.

BACKGROUND

Endothelial dysfunction has been shown to occur in patients with diabetes mellitus (DM), and chronic hyperglycemia is implicated as a cause of endothelial dysfunction. However, in many patients with Type 2 DM and in those with impaired glucose tolerance (IGT), fasting blood glucose may be within normal limits, and hyperglycemia occurred only post-prandially.

METHODS

With ultrasound technique, we measured flow-mediated endothelium-dependent vasodilation during oral glucose tolerance test in 58 subjects: (17 patients with normal glucose tolerance [NGT], 24 with IGT, and 17 with type 2 DM). In addition, we measured the levels of thiobarbituric acid reactive substances (TBARS) and nitrite/nitrate.

RESULTS

Flow-mediated vasodilation decreased after glucose loading (NGT: 7.53+/-0.40, 4.24+/-0.28 and 6.35+/-0.40, in fasting, at 1- and 2-h, respectively, IGT: 6.50+/-0.48, 1.40+/-0.41** and 4.00+/-0.47*, respectively; DM: 4.77+/-0.37, 1.35+/-0.38** and 1.29+/-0.29%**, respectively; *p < 0.01 vs. fasting, **p < 0.005 vs. fasting). The TBARS concentration increased in parallel with plasma glucose level in each group (NGT: 1.43+/-0.07, 2.03+/-0.12 and 1.80+/-0.12, respectively; IGT: 1.65+/-0.11, 2.46+/-0.12** and 1.94+/-0.08*, respectively; DM: 1.73+/-0.07, 2.34+/-0.08** and 2.47+/-0.09** nmol/ml, respectively; *p < 0.05 vs. fasting, **p < 0.01 vs. fasting). Glucose loading did not change nitrite/nitrate concentration in any of the groups.

CONCLUSIONS

Hyperglycemia in response to oral glucose loading rapidly suppresses endothelium-dependent vasodilation, probably through increased production of oxygen-derived free radicals. These findings strongly suggest that prolonged and repeated post-prandial hyperglycemia may play an important role in the development and progression of atherosclerosis.

Association of plasma levels of activated protein C with recanalization of the infarct-related coronary artery after thrombolytic therapy in acute myocardial infarction

Protein C is one of the most important antithrombotic components. After activation by the thrombin-thrombomodulin complex on endothelial cells, activated protein C (APC) inactivates factors Va and VIIIa, which leads to the inhibition of thrombin formation. We examined the association of plasma levels of APC with the responsiveness to coronary thrombolytic therapy of the infarct-related coronary artery in patients with acute myocardial infarction (AMI). Plasma levels of APC, thrombin-antithrombin III complex (TAT), and plasminogen activator inhibitor (PAI) activity were measured in 32 consecutive AMI patients who underwent coronary angiography followed by thrombolytic therapy, and compared to the measurements in 23 control subjects. On admission, APC levels (ng/mL) were significantly elevated in patients with AMI, as compared with controls (2.5+/-0.4 vs. 1.2+/-0.2, 1.3+/-0.2, respectively, p<0.01). At discharge, plasma levels in AMI patients decline to values not significantly different from those in controls. (1.2+/-0.2, 1.3+/-0.2, respectively). TAT levels (ng/mL) were different among the groups in a fashion similar to that of APC (14.1+/-3.1 on admission vs. 3.3+/-0.4 at discharge, 1.8+/-0.1 in the control subjects, respectively, p<0.01). PAI activity levels (IU/mL) were higher on admission than at discharge and higher than the control subjects (19.7+/-1.8 vs. 10.5+/-1.0, 5.4 +/- 0.7, respectively, p<0.01). Thirty-two patients with AMI were classified into two groups according to the results of thrombolysis: the success group (24 patients) and the failure group (eight patients). APC levels were higher in the failure group than in the success group (5.1+/-0.7 vs. 1.6+/-0.2, p<0.01). TAT levels were also higher in the failure group than in the success group (30.8+/-9.6 vs. 8.6+/-1.7, p<0.01). PAI activity levels (IU/mL) were lower in the failure group than in the success group (13.5+/-3.1 vs. 21.7+/-2.1, p<0.05). There were correlations between APC and TAT levels both on admission (r=0.75, p<0.0001) and at discharge (r=0.71, p<0.0001). Elevated APC was thought to correlate with increased thrombin generation in patients with AMI. This study demonstrated that there was a significant relation between plasma APC level and the responsiveness to thrombolytic therapy of the infarct artery. This study may also indicate that increased thrombin generation is a cause of the resistance to thrombolytic therapy.

Enhanced gamma (30-150 Hz) frequency in the human medial temporal lobe

We performed fast Fourier transformation power spectral analysis of the electrocorticogram in human medial temporal lobe during wakeful rest in six epileptic subjects. Compared with the electrocorticogram wave in the basal temporal lobe, which showed monotonic decline of spectral power across the frequency axis, the electrocorticogram wave in the parahippocampal gyrus was enhanced (or did not decline) in the gamma frequency range (30-150 Hz) in all subjects. Although it has been suggested that electrical oscillations of the hippocampus have functional roles in higher brain functions, namely learning and memory, the knowledge of hippocampal oscillations is largely limited to animal studies. The present results demonstrate that fast frequency oscillation is also present in the human medial temporal lobe, which has been reported in animal hippocampi. They also demonstrate the importance of recording very fast field potentials in human electrocorticograms. This fast oscillation is likely to play important functional roles related to learning and memory, possibly to induce long-term potentiation in the human medial temporal lobe.

Improvement of endothelial vasomotor dysfunction by treatment with alpha-tocopherol in patients with high remnant lipoproteins levels

OBJECTIVES

This study sought to examine whether oral intake of alpha-tocopherol, an antioxidant, could improve endothelium-dependent vasorelaxation in patients with high remnant lipoproteins levels.

BACKGROUND

Remnant lipoproteins are known to be atherogenic and impair endothelium-dependent arterial relaxation, but the underlying mechanisms remain unclear. Oxidative stress is a common feature of various risk factors for atherosclerosis.

METHODS

Flow-mediated vasodilation of the brachial artery during reactive hyperemia was examined by high resolution ultrasound technique before and at the end of 4 weeks treatment with oral administration of alpha-tocopherol acetate (300 IU/day) or placebo, which was randomly assigned, in 40 patients with high serum levels of remnants and in 30 patients with low remnants levels in the fasting state (>75th percentile and <25th percentile, respectively, of the distribution of remnants levels in 150 consecutive hospitalized patients).

RESULTS

Before treatment, flow-mediated vasodilation was lower in patients with high remnants levels than in those with low levels (4.1 +/- 0.3% vs. 6.0 +/- 0.5%, p < 0.01). Treatment with alpha-tocopherol but not with placebo significantly increased flow-mediated dilation in patients with high remnants levels (7.5 +/- 0.4% after alpha-tocopherol vs. 4.2 +/- 0.4% after placebo, p < 0.01). In patients with low remnants levels, alpha-tocopherol was not effective. The beneficial effect with alpha-tocopherol in high remnants patients was associated with decrease in plasma levels of thiobarbituric acid reactive substances, an indicator of lipid peroxidation (6.6 +/- 0.3 nmol/ml before alpha-tocopherol vs. 4.6 +/- 0.3 after alpha-tocopherol, p < 0.05).

CONCLUSIONS

Alpha-tocopherol improved impairment of endothelium-dependent vasodilation in patients with high remnants levels. The increase in oxidative stress may at least partly contribute to endothelial vasomotor dysfunction, in patients with high remnants levels.

Relationship between serum angiotensin-converting enzyme activity and plasma plasminogen activator inhibitor activity in patients with recent myocardial infarction

BACKGROUND

An elevated level of angiotensin-converting enzyme (ACE) has been demonstrated to increase the risk of myocardial infarction. Plasminogen activator inhibitor (PAI) is the most important physiological inhibitor of tissue plasminogen activator in plasma. An elevated level of PAI has been reported to be associated with decreased fibrinolytic capacity and to constitute a marker of the risk for recurrent coronary thrombosis.

METHODS

We measured the serum ACE activity and plasma PAI activity in 34 patients with recent myocardial infarction, and evaluated the correlation between these two values by linear regression analysis. We also administered captopril (37.5 mg/day) to 17 of these patients and placebo to the other 17 patients at random, and compared the changes in PAI activity and ACE activity in these two groups over a 1-month period.

RESULTS

There was a significant correlation between the serum ACE activity and the plasma PAI activity at baseline in the patients (r = 0.498, P < 0.01). The captopril-treated patients showed significantly reduced PAI activity (P < 0.01), and a concomitant decrease in ACE activity.

CONCLUSION

These results suggest that elevated ACE activity is associated with impaired fibrinolysis and that treatment with an ACE inhibitor improves the fibrinolytic function in patients with recent myocardial infarction. The results also suggest that the renin-angiotensin system plays a role in the increased risk of ischemic cardiovascular events when it is activated, and in the reduction of risk of recurrent myocardial infarction by ACE inhibition.

In situ synthesis of beta-glucan microfibrils on tobacco plasma membrane sheets

A major concern in plant morphogenesis is whether cortical microtubules are responsible for the arrangement and action of beta-glucan synthases in the plasma membrane. We prepared isolated plasma membrane sheets with cortical microtubules attached and tested whether beta-glucan synthases penetrated through the membrane to form microfibrils and whether these synthases moved in the fluid membrane along the cortical microtubules. This technique enabled us to examine synthesis of beta-glucan as a fiber with a two-dimensional structure. The synthesis of beta-glucan microfibrils was directed in arrays by cortical microtubules at many loci on the membrane sheets. The microfibrils were mainly arranged along the microtubules, but the distribution of microfibrils was not always parallel to that of the microtubules. The rate of beta-glucan elongation as determined directly on the exoplasmic surface was 620 nm per min. When the assembly of microtubules was disrupted by treatment with propyzamide, the beta-glucans were not deposited in arrays but in masses. This finding shows that the arrayed cortical microtubules are not required for beta-glucan synthesis but are required for the formation of arranged microfibrils on the membrane sheet.

A biosynthetic intermediate of phytoalexins in banana fruits

Phytoalexins of Musa balbisiana [BBB] cv Saba sa Hapon and cv Mundo fruits were compared with those of M. acuminata [AAA] cv Buñgulan fruits. Phytoalexins induced by wound and inoculation of Colletotrichum musae in these two cultivars were the same as those of Buñgulan. In the course of analysis of the phytoalexins, 2-phenyl-1,8-naphthalic anhydride, 2-(4'-methoxyphenyl)-1,8-naphthalic anhydride, and 1,2,3,4-tetrahydro-6,7-dihydroxy-1-(4'-hydroxycinnamyliden)naphthalen-2-one were found as new phytoalexins of banana fruits. This latter compound is probably a biosynthetic intermediate of phenylphenalenones in banana fruits.

Superiority of hepatic arterial infusion in preventing catabolism of 5-FU compared with portal vein infusion revealed by an in vivo 19F NMR study

PURPOSE

The aim of this study was to identify the route of administration of 5-FU with the greatest pharmacological advantage in a rat model using non-invasive in vivo 19F nuclear magnetic resonance (NMR) spectroscopy.

METHODS

5-FU (50 mg/kg) was administered to anesthetized Wistar rats cannulated into the hepatic artery, portal vein or tail vein and 11 NMR spectra were acquired from the liver region to 60.5 min every 5.5 min.

RESULTS

With systemic i.v. (tail vein) infusion, the 19F-NMR signal for 5-FU from the liver region peaked in the first spectrum (0-5.5 min), and then gradually decreased. The signal for the 5-FU catabolite alpha-fluoro-beta-alanine (FBAL) gradually increased to the sixth spectrum (0-33.0 min) and then plateaued. Following portal vein infusion the intensity of the first 5-FU spectrum was twice as high as that following i.v. infusion, but the intensity decreased and the FBAL signal increased gradually in the sixth spectrum as systemic i.v. infusion. In contrast, the intensity of the 5-FU signal following hepatic artery infusion was the same as that following portal vein infusion in the first spectrum, and maintained a strong intensity to the final spectrum (60.5 min). The FBAL signal was detected from the second spectrum following hepatic artery infusion, but its intensity was significantly weaker than that following i.v. or portal vein infusion.

CONCLUSIONS

Hepatic arterial infusion resulted in the active form of 5-FU being present for a longer time and its degradation in the liver being suppressed compared with the results following portal vein infusion. This catabolic advantage of hepatic arterial infusion could lead to a more potent anti-tumor activity against liver metastases, but could also lead to significant host toxicity including biliary toxicity. We recommend that the dose/schedule of 5-FU administered via the hepatic artery should be adjusted carefully.

Reaction times of head movements occurring in association with express saccades during human gaze shifts

During lateral gaze shifts to a visual target of 10 degrees eccentricity, the gap paradigm (presence of a 200 ms gap between offset of fixation lamp and onset of target lamp) produced a significant decrease in the reaction times (RTs) of head movements (54 ms) and saccades (82 ms) when compared with those obtained under the overlap paradigm across five subjects. Correlation coefficients between the RTs of saccades and head movements were significantly lower under the gap paradigm than those under the overlap paradigm. Particularly, the RTs of head movements occurring in association with express saccades were independent of the saccade RTs. These results indicate that the head and eye motor systems are controlled by the separate neural mechanisms in the conditions which produce express saccades.

Morphology of single primary spindle afferents of the intercostal muscles in the cat

A reconstruction was made of the trajectory of primary spindle afferents from the intercostal muscles in the spinal cord of the cat. Intraaxonal recordings were performed from the primary spindle afferents that were identified by their response to lung inflation and stimulus threshold to activate the action potentials. The afferents were stained by using intraaxonal injection of horseradish peroxidase (HRP). Results were obtained mainly from internal intercostal Ia fibers, which entered the spinal cord and bifurcated into ascending and descending branches. The ascending branches could be traced up to 10.7 mm, and the descending branches could be traced up to 7.3 mm. The ascending branches extended to the next segment. Collaterals ranging from one to six were given off from these branches. The distances between adjacent collaterals ranged from 0.9 mm to 4.7 mm. Each collateral had similar morphological characteristics. The collaterals entered the dorsal horn and ran toward lamina IX through the medial half of the gray matter. Fine branches and boutons were given off in laminae V, VII, VIII, and IX. The aggregations of these branches were found in lamina VII, mainly in the region of Clarke's column and in the ventral and ventrolateral regions thereof and in lamina IX, mainly in the nucleus lateromedialis. Most terminals did not contact the somata of target neurons in all laminae in which terminals were found. However, a few terminals were found to contact large neurons in lamina IX. In addition to these aggregates, there were some terminals scattered throughout the ventral horn. Thus, it was concluded that single intercostal Ia afferents project to the region of Clarke's column, to the intercostal motor nucleus, and to the intermediate regions.

A metastasis to the nasal tip from a cervical carcinoma--a case report

Metastases to the nasal tip from gynecological malignancies are extremely rare. We present a case of a tumor metastatic to the nasal tip from a carcinoma of the uterine cervix. We administered high-dose focal irradiation to the site of the tumor. The literature on metastases to the nose, maxillary sinuses, and paranasal sinuses from gynecologic malignancies is reviewed.

A new preoperative immunochemotherapy for the treatment of locally advanced esophageal cancer

A promising preoperative immunochemotherapy regimen for locally advanced esophageal cancer is herein described. A 67-year-old man suffering from severe dysphagia was diagnosed with unresectable esophageal cancer at initial examination because of a tumor of 11 cm in length and suspicion of trachea invasion. Neoadjuvant immunochemotherapy was undertaken for the down-staging. Interleukin-2 (IL-2) (3.5 x 10(5) Japan reference units), nedaplatin (7 mg/m2) and 5-FU (300 mg/m2) were administered intravenously daily for 5 days a week for three weeks. The gross findings of a barium esophagogram and esophagoscopy revealed significant tumor regression in both size and shape. The patient underwent an esophagectomy through a laparotomy followed by a right thoracotomy. The surgical specimens were serially sectioned and examined microscopically. All of the surgical margins were clear (upper and lower margins as well as the adventitia), and there was no evidence of lymph node metastasis. The surgical specimen revealed neoplastic squamous ghost cells surrounding significant lymphocyte infiltration. This appears to be a unique feature of this particular neoadjuvant immunochemotherapy.

Effects of (+)-8',8',8'-trifluoroabscisic acid on alpha-amylase expression and sugar accumulation in rice cells

The effects of (+)-8',8',8'-trifluoroabscisic acid (trifluoro-ABA) on alpha-amylase expression were studied in rice embryoless half-seeds, scutella, and suspension-cultured cells derived from the embryo, and the effects of the analog on sugar accumulation were also studied in scutella and suspension-cultured cells. Treatment with (+)-trifluoro-ABA strongly inhibited the gibberellic acid-inducible expression of alpha-amylase I-1 encoded by RAmy1A in the aleurone layers of embryoless half-seeds at the levels of transcription, protein synthesis, and enzyme activity. It was also found that (+)-trifluoro-ABA stimulated (i) the uptake of glucose from the incubation medium and (ii) the synthesis of sucrose in scutellar tissues and suspension-cultured cells of rice. The biological activity of (+)-trifluoro-ABA was found to be more potent and persistent than that of natural ABA. We further examined the effects of trifluoro-ABA on the expression of alpha-amylase I-1 in scutellar tissues and suspension-cultured cells. It was found that (+)-trifluoro-ABA did not inhibit the formation of alpha-amylase I-1 in the absence of external glucose. However, glucose and (+)-trifluoro-ABA cooperatively suppressed the formation of alpha-amylase I-1. Judging from these results, we conclude that the regulatory mechanism for the expression of alpha-amylase I-1 in the scutellar epithelium is distinguishable from that operating in the aleurone layer.

Problems with assays based on fibrin clot formation principle: analysis of multilaboratory data

In order to investigate the inter-laboratory differences of coagulation assays, three different control plasmas were distributed for coagulation assays to 162 institutes. Three types of coagulation tests, that is, prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen (Fbg) assay were carried out by routine methods in each institute. In our laboratory, the Fbg concentrations were measured in two different plasmas using one instrument and nine reagents, and the Fbg concentrations were measured in ten control plasmas using three instruments and one reagent. Results were obtained as follows: (1) The coefficient of variance (CV) for control plasma with the highest value was significant in the PT assay and APTT assay. (2) Inter and intra-institute differences in PT and APTT assays were observed when the reagent or the instrument used was changed. (3) Inter and intra-institute differences in PT and APTT assays were also observed when both the reagent and the instrument were changed. (4) Inter and intra-institute differences in the PT and APTT assays were observed between the manual and the mechanical methods. (5) The CVs for the Fbg assays were the largest in the plasma at the lowest concentration of the three plasmas. (6) When control plasmas of three different Fbg concentrations were assayed, the number of the institutes which obtained a value greater than 3 standard deviations (SDs) was highest for the control plasma with the lowest concentrations of Fbg, and some of the instruments were not able to measure such a low Fbg concentration. (7) When the fibrinogen concentration was measured in various kinds of commercially-available control plasmas with a calibrated instrument, the values determined were different from the assigned ones and varied significantly from instrument to instrument. From the results, we concluded that standardization of the quality of control plasma, and its value assignment to the plasma should be established as soon as possible, and that a reliable standard fibrinogen assay should be developed.

Involvement of liver-associated immunity in hepatic metastasis formation

AIMS

Hepatic metastasis formation and prevention were studied from the viewpoint of liver-associated immunity.

METHODS

RCN-9, a colonic cancer cell line derived from Fischer rats, and its subclone RCN-H4, in which the cancer is highly metastatic to the liver, were used. Fischer rats that were inoculated with parent RCN-9 colonic cancer cells (5 x 10(6)) via the portal vein showed liver metastasis in less than 60% of the animals. In contrast, all rats (100%) that received RCN-H4 produced multiple liver metastases. To investigate the difference of hepatic metastasis formation, we assessed the susceptibility of both cell lines against hepatic sinusoidal lymphocytes (HSL) by 51Cr-release assay, and the expression of MHC class I and class II of both cell lines by flow cytometry. In addition, we examined whether activation of HSL by interleukin-12 (IL-12) can prevent liver metastasis of highly metastatic clone RCN-H4.

RESULTS

The RCN-H4 clone showed decreased susceptibility to lysis by natural cytotoxic cells in HSL. This decrease in cell susceptibility was attributable to an increase in cell surface expression of MHC class I antigen. Administration of IL-12, a potent NK/CTL stimulatory cytokine, augmented the cytotoxic activity against the RCN-H4 clone and prevented liver metastasis of RCN-H4 inoculated into the portal vein.

CONCLUSIONS

Liver metastasis formation is positively correlated with the strength of the hepatic immune system which mainly consists of ontogenetically primitive T cells. As these effectors exert their cytotoxicity in a MHC-nonrestricted fashion, tumor cells that highly express MHC class I antigen can readily avoid hepatic surveillance and apt to cause liver metastasis. Augmentation of the hepatic immune system, for instance, with IL-12 administration, can prevent liver metastasis even in tumor cells with a high potential for liver metastasis.

Serial changes in plasma levels of soluble P-selectin in patients with acute myocardial infarction

The present study examines whether an acute inflammatory response occurs during acute myocardial infarction (AMI) by measuring soluble P-selectin levels. We examined plasma soluble P-selectin levels in 16 consecutive patients with AMI, in 15 patients with angina, and in 13 control subjects with chest pain but normal coronary arteries and no coronary spasm. In patients with AMI, blood samples were obtained immediately after admission and at 1, 4, 24, and 48 hours, and 1 week after initiation of reperfusion therapy. The plasma soluble P-selectin levels were significantly higher in the AMI group on admission than in the other 2 groups (83 +/- 13 ng/ml, p < 0.01). The plasma soluble P-selectin levels at baseline were not significantly different between the angina and control groups (28 +/- 4 vs 24 +/- 5 ng/ml, p = NS). Plasma soluble P-selectin levels reached their peak significantly at 4 hours after initiation of the reperfusion therapy in patients with AMI. The peak level was significantly higher than the level on admission (115 +/- 17 vs 83 +/- 13 ng/ml, p < 0.05). The plasma soluble P-selectin levels were higher in the AMI group than in the angina and control groups over the time course (p < 0.01). Our data indicate that the plasma soluble P-selectin levels are increased in patients with AMI, and that the levels are increases after reperfusion therapy more than before reperfusion. We suggest that the increase in the plasma soluble P-selectin levels may be caused by the activation of endothelial cells and platelets after myocardial ischemia and reperfusion during AMI.

Cardiotonic activity of the rhizome of Polygonatum sibiricum in rats

The cardiotonic effect of the rhizome of Polygonatum sibiricum was investigated in the left atria of rats. The methanol extract of the rhizome of Polygonatum sibiricum (OM) (1-7 mg/ml) concentration-dependently increased the developed tension of the left atrium. It also strongly inhibited cAMP phosphodiesterase. The increase cAMP level correlated the increase in left atrial contraction. On the other hand, OM did not inhibit Na+, K+-ATPase. The cardiotonic effect of OM was strongly inhibited by reserpine, a sympatholytic agent. Furthermore, OM-treated left atria inhibited the tension produced by propranolol, a beta adrenocepter antagonist. These findings suggested that the cardiotonic effect is due to stimulating beta adrenoceptors through activation of sympathetic nerves.

Purification and characterization of Bombyx mori chitinases

Two isozymes of chitinase (EC 3.2.1.14) were purified from the fifth-instar larvae of Bombyx mori by chromatography on DEAE-Cellulofine A-500, hydroxylapatite, Butyl-Toyopearl 650M, and Fractogel EMD DEAE 650 (M). These two isozymes were glycoproteins with different apparent molecular masses of 65 and 88 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pHs of the 65 and 88 kDa chitinases were 5.5 and 6.5, respectively, towards a short substrate, N-acetylchitopentaose (GlcNAc5), whereas their high activities were observed in a wide pH range between 4 and 10 towards a longer substrate, glycolchitin. Steady-state kinetic analysis of these chitinases was performed using a series of N-acetylchitooligosaccharides (GlcNAcn, n = 2-6) and glycolchitin as the substrates. Kinetic parameters for both chitinases could be obtained in the hydrolysis of glycolchitin, but not in that of N-acetylchitooligosaccharides because of strong substrate inhibition. Both chitinases similarly hydrolysed N-acetylchitooligosaccharides except for GlcNAc2 as follows: GlcNAc3 to GlcNAc plus GlcNAc2, GlcNAc4 to two molecules of GlcNAc2, GlcNAc5 to GlcNAc2 plus GlcNAc3, and GlcNAc6 to GlcNAc2 plus GlcNAc4 as well as two molecules of GlcNAc3. These results suggest that these chitinases are endo-type hydrolases, and preferred the longer-chain N-acetylchitooligosaccharides. With respect to activity, the 65 kDa chitinase was 1.7-fold more active than the 88 kDa chitinase with regard to the initial velocity in the reaction of 0.1 mM N-acetylchitooligosaccharides (GlcNAcn, n = 3-6), whereas in the overall reaction of glycolchitin (kcat/K(m)), the 88 kDa chitinase was four times more active than the 65 kDa chitinase. Regarding the affinity (1/K(m)) to glycolchitin, the affinity of the 88 kDa chitinase was 5.8-fold higher than that of the 65 kDa chitinase. The protein amino acid and gene nucleotide sequences were partly determined. Both N-terminal amino acid sequences of the 65 and 88 kDa chitinases were identical as ADSRARIVXYFSNWAVYRPG. The partial amino acid (113 amino acids) and nucleotide sequences (278 nucleotides) analysed from a mixture of 65 and 88 kDa chitinases included the two conserved regions of the family of 18 glycosyl hydrolases. All these results suggest that the B. mori chitinases are similar to Manduca sexta chitinase in primary structure and kinetic behaviour, and may be involved in the initial and intermediate stages of chitin degradation.

Effects of fructose-induced hypertriglyceridemia on hepatorenal toxicity of acetaminophen in rats: role of pharmacokinetics and metabolism of acetaminophen

Fructose-induced hypertriglyceridemic rats become resistant to hepatotoxicity and susceptible to nephrotoxicity of acetaminophen (APAP), as compared with normal ones. The present study was designed to test the hypothesis that alterations in the distribution of APAP and in the intrinsic susceptibility to toxicants are responsible for the alteration in hepatorenal toxicity of APAP in fructose-induced hypertriglyceridemic rats. Following APAP-administration (750 mg/kg, i.p.), fructose-pretreated rats (25% fructose in drinking water for 5 weeks) showed nephrotoxicity of APAP more promptly and more severely than normal ones. Renal APAP-concentrations at the early phase (15 and 30 min. after APAP-administration) were significantly greater in fructose-pretreated rats than those in normal ones. Plasma and hepatic APAP concentrations in fructose-pretreated rats were greater than those in normal ones only at the later phase (plasma; 6 hr, liver; 6 and 12 hr after APAP-administration). There were no significant differences in the APAP-induced depletion of hepatic and renal glutathione and in the basal hepatic and renal cytochrome P-450 contents between these rats. Fructose-pretreated rats were also more susceptible to p-aminophenol (PAP), a nephrotoxic metabolite of APAP, than normal rats. Therefore, enhanced susceptibility to APAP-nephrotoxicity in fructose-pretreated rats may be due, at least in part, to increased renal APAP concentration and increased intrinsic susceptibility to the metabolic nephrotoxicant.

Transient late neonatal hypocalcemia with high serum parathyroid hormone

We report two patients with transient late neonatal hypocalcemia. Serum examination showed low calcium (Ca), high phosphorus, high parathyroid hormone (PTH), normal 25-hydroxyvitamin D and low or normal 1,25-dihydroxyvitamin D (1,25(OH)2vitD) levels. PTH infusion test revealed normal cyclic AMP production. In these patients, 1,25(OH)2vitD production by PTH, or Ca mobilization from bone and Ca absorption from intestine by PTH and 1,25(OH)2vitD might have been disturbed transiently due to developmental immaturities. This is a new type of transient late neonatal hypocalcemia with high serum PTH levels.

Effects of fructose-induced hypertriglyceridemia on hepatorenal toxicity of acetaminophen in rats. II. Role of enhancement of fructose metabolism and overproduction of triglyceride in the liver and kidney on hepatorenal toxicity of acetaminophen

Fructose-induced hypertriglyceridemic rats are resistant to hepatoxicity and susceptible to nephrotoxicity of acetaminophen (APAP) as compared with normal ones. The present studied were designed to evaluate how fructose-treatment affects the developmental mode of hepatorenal toxicity of APAP. First, following fructose-pretreatment for various durations (1 day, 1 week or 3 weeks), 1-day-fructose-pretreatment induced hypertriglyceridemia and enhancement of APAP-nephrectoxicity simultaneously. However, it took at least 3 weeks for fructose-pretreatment to reduce APAP-hepatotoxicity. Second, following fructose, sucrose or glucose-pretreatment for 3 weeks, fructose-pretreated rats showed marked hypertriglyceridemia and modification of APAP-hepatorenal toxicity. Sucrose-pretreated rats showed less effects than fructose-pretreated rats. Glucose-pretreated rats showed no changes in plasma triglyceride and APAP-hepatorenal toxicity. Third, rats with hypertriglyceridemia induced by olive oil or Triton WR-1339 which did not produce enhanced metabolism and triglyceride-overproduction in the liver and kidney showed no modification of APAP-hepatorenal toxicity. Pretreatment of glycerol which was metabolized in liver and kidney and induced an overproduction of triglyceride resulted in an enhancement of APAP-nephrotoxicity. These results indicate that an enhancement of fructose metabolism and an overproduction of triglyceride in liver and kidney are responsible for the modification of APAP-hepatorenal toxicity in fructose-induced hypertriglyceridemic rats.