Determination of catecholamines and their 3-O-methyl metabolites in mouse plasma

The determination of catecholamines and their 3-O-methyl metabolites in a single mouse plasma is necessary to understand the role of the sympathetic nervous activity, while the inactivation of catecholamines by catechol-O-methyltransferase indicates the activity of blood pressure regulation in animals. Here we report the basal catecholamines and their 3-O-methyl metabolite concentrations obtained from 15 microL of mouse plasma utilizing semi-microcolumn high-performance liquid chromatography (HPLC)-peroxyoxalate chemiluminescence detection system. The concentrations were 6.63 +/- 1.37 pmol/mL plasma, 0.49 +/- 0.10 pmol/mL plasma, 5.25 +/- 2.30 pmol/mL plasma, 3.23 +/- 0.84 pmol/mL plasma, 0.44 +/- 0.11 pmol/mL plasma, and 3.39 +/- 1.67 pmol/mL plasma for norepinephrine, epinephrine, dopamine, normetanephrine, metanephrine and 3-methoxytyramine, respectively (n = 5-7). Further, when blood pressure was reduced by minoxidil, plasma catecholamines were found to be significantly increased by the baroreflex-mediated response in mouse.

Experimental study of fast and ultrafast T2-weighted imaging sequences using AMI-25 superparamagnetic iron oxide (SPIO)

The objective of this study was to evaluate fast and ultrafast T2-weighted images (T2WI), including echo planar imaging (EPI), using an AMI-25 agar phantom. Image quality for conventional spin echo (CSE) and turbo spin echo (TSE) was almost equivalent. In high-resolution TSE, image quality was highest due to the use of a 512 x 256 matrix. Half-Fourier single-shot turbo SE (HASTE) was associated with blurring of images, and turbo-gradient SE (TGSE) showed a deterioration of image quality. EPI also suffered from poor image quality because this method is very sensitive to magnetic field inhomogeneity. CSE showed good signal-to-noise ratio (S/N) and contrast ratio (CR), but also required the longest imaging times. Among the TSE sequences, TSE with a short echo train length (ETL) was superior in terms of S/N. The CR of EPI and fast low angle shot (FLASH) images were improved in proportion to the effective echo time (TE). At present, TSE is inferior to CSE in terms of S/N and CR. However, taking into consideration scanning time, TSE with a short ETL is thought to be suitable for routine examinations. Effective TE is an important factor in gradient echo (GRE) examinations.

Nontumorous decrease in Tc-99m GSA accumulation

Nontutimorous decrease in 99mTc-GSA accumulation has not been well covered in the literature. Understanding of this phenomenon is, however, essential for accurate evaluation of regional hepatic function. Scintigrams (transaxial SPECT) of 269 patients who underwent 99mTc-GSA liver scintigraphy were reviewed for the presence of nontumorous decreases in 99mTc-GSA accumulation. Nontumorous decreases in 99mTc-GSA accumulation were seen in 32 of 269 patients (12%). In 16 of the 32 patients (6%), nontumorous decreases in 99mTc-GSA accumulation corresponded to regional decrease in portal venous flow. The causes of such decrease in portal venous flow were portal thrombus of hepatocellular carcinomas in eight patients, portal venous stenosis or occlusion by hilar cholangiocarcinomas in five patients, inter alia. In eight patients (3%), the regions with decreased 99mTc-GSA accumulation correlated with massive hepatic necrosis in fulminant hepatitis, scar in hepatitis, or confleuent in portal venous flow, lobar biliary stasis, or both. In four patients (1.5%), the exact causes of nontumorous decrease in 99mTc-GSA accumulation could not be determined.

Long-term culture of glutamine synthetase-transfected HepG2 cells in circulatory flow bioreactor for development of a bioartificial liver

Glutamine synthetase (GS) is involved in an accessory pathway of ammonia removal in mammals. To develop a bioartificial liver with a human cell line, GS gene was transfected into HepG2 cells, which had no ammonia removal activity. After culturing in the presence of methionine sulfoximine (MSX), a GS inhibitor, we obtained a MSX-resistant HepG2 subline (GS-HepG2), which had amplified GS gene; ammonia removal activity was estimated to be 1/7 of that of rat primary culture hepatocytes. The cells were cultured in a circulatory flow bioreactor for 109 days, while they multiplied from 5 x 10(7) to 4 x 10(9) cells. Three days after inoculation, the ammonia level of the culture medium was lowered to a level maintained thereafter, suggesting that using recombinant cell lines for bioartificial livers enables long-term repeated treatment for hepatic failure patient. Judging from the rate of decrease in the amount of the added ammonia, the ammonia removal capability of 4 x 10(9) GS-HepG2 cells was almost equivalent to 5 x 10(8) porcine hepatocytes inoculated into the circulatory flow bioreactor. Apart from their ammonia removal activity, GS-HepG2 cells eliminated human tumor necrosis factor-alpha (TNF-alpha). Cytokine removal therefore promises to be another useful property of bioreactor cells.

An automatic analyzer for catecholamines and their 3-O-methyl metabolites using a micro coulometric flow cell as a postcolumn reactor for fluorogenic reaction

A coulometric flow cell for a miniaturized LC system was developed. The cell was examined, as 3-O-methyl catecholamines were converted to their relative omicron-quinones for subsequent fluorometric and chemiluminescence detection. Its performance was evaluated in comparison with commercially available amperometric and coulometric detectors in terms of specification of the low dead volume and high conversion efficiency. The fully automated small-bore LC analyzer for simultaneous determination of catecholamines and their 3-O-methyl metabolites included precolumn pretreatment, column switching, column separation, postcolumn oxidative conversion, fluorometric derivatization, and chemiluminescence detection. The detection limits were 0.3-2.0 fmol for catecholamines and their 3-O-methyl metabolites. Because of the high sensitivity, the required volume of rat plasma sample was only 15 microL.

Effects of endotoxin and tumor necrosis factor alpha on regional brain neurotransmitters in mice

Alterations in regional brain concentration of dopamine (DA), norepinephrine (NE), serotonin (5-HT) and their metabolites were investigated in male BALB/c mice injected intraperitoneally with bacterial lipopolysaccharide (LPS, 2 mg kg(-1)) or recombinant murine tumor necrosis factor alpha (TNFalpha, 0.1 mg kg(-1)) at 2, 6, 12 and 24 h after the injection. At 2 h post-injection the LPS administration resulted in hypothermia, which was not apparent at later time points. No consistent effects were observed by either LPS or TNFalpha on peripheral leukocyte counts or plasma transaminase levels. Both LPS and TNFalpha slightly elevated NE metabolism in the striatum at 2-12 h. Concentrations of DA and its metabolites were significantly elevated only in the hypothalamus following TNFalpha at 24 h. Tumor necrosis factor alpha exerted pronounced effects on 5-HT metabolism in most brain regions at 2 h. Results suggest that the effect of LPS is more complex compared with TNFalpha because of the endogenous production of other cytokines including the TNFalpha.

Early fumonisin B1 toxicity in relation to disrupted sphingolipid metabolism in male BALB/c mice

Fumonisin B1 is a mycotoxin produced by Fusarium moniliforme, a common fungus in corn. It is known to cause a variety of diseases, including hepatic and renal degeneration in many species of laboratory and domestic animals. The known biochemical events in fumonisin B1 toxicity involve inhibition of ceramide synthase leading to disruption of sphingolipid metabolism. The effect of fumonisin B1 on ceramide and more complex sphingolipids in mice is not known. Groups of five male BALB/c mice each were injected with fumonisin B1 subcutaneously at doses of 0, 0.25, 0.75, 2.25, and 6.75 mg/kg body weight daily for 5 days. This protocol has been shown to produce a dose-dependent increase in apoptosis in liver and kidney of these animals. In the present study, liver, kidney, and brain were sampled and analyzed for free sphingoid bases and complex sphingolipids one day after the last treatment. A dose-related accumulation of free sphinganine and sphingosine was observed in liver and kidney, but not brain. The maximal increase in free sphinganine in kidney was 10-fold greater than in liver. Total phospholipids increased only in liver, whereas ceramide levels were not consistently altered in liver, kidney, or brain. In liver and kidney, fumonisin B1 treatment increased the sphinganine-containing complex sphingolipids, but no effect was observed on sphingosine-containing complex sphingolipids. No changes in complex sphingolipids were observed in brain. In liver, there was a close correlation between the extent of free sphinganine accumulation, and apoptosis and hepatopathy. This correlation was also evident in kidney but to a lessor extent. Nonetheless, the apoptosis and nephropathy occurred with little or no change in the levels of ceramide or more complex sphingolipids.

Increased production of proinflammatory cytokines by murine macrophages following oral exposure to sodium selenite but not to seleno-L-methionine

Selenium (Se) is an essential as well as a toxic trace element in animal and human nutrition. The immune system is a known target of Se intoxication. The objectives of the present study were to determine the effects of oral exposure to inorganic and organic forms of Se on the murine immune system and to compare the relative toxicity of the different chemical forms. Male BALB/c mice, 6-7 weeks of age, were exposed continuously to 0, 1, 3 or 9 ppm of Se as sodium selenite or seleno-L-methionine in the drinking water for 14 days. Following the treatment period mice were euthanized; trunk blood, spleen, thymus, liver and kidney were aseptically collected and organs weighed. Single-cell splenocyte cultures were made from the spleens and used to determine the effects of Se treatment on mitogen-induced lymphocyte blastogenesis and cytokine production. There were no changes in the 0 and 1 ppm Se groups as selenite. The thymus/body weight ratio was significantly reduced at 3 ppm Se as sodium selenite, and all other parameters remained unaffected. Exposure to 9 ppm of Se as sodium selenite resulted in marked decrease in body weight gain and relative organ weights. Treatment of mice with 9 ppm Se as sodium selenite increased erythrocyte counts in peripheral blood, reduced splenic cellularity, but increased the basal rate of splenocyte proliferation and induced a dose-dependent increase in phytohemagglutinin-P-induced lymphocyte proliferation. Sodium selenite at this dose increased the production of proinflammatory cytokines, tumor necrosis factor alpha and interleukin-1 beta, in lipopolysaccharide-stimulated splenic macrophages. Mice exposed to Se as seleno-L-methionine in the drinking water did not display any effects on the parameters examined at the dose range in this study. Results indicated that splenic macrophages and lymphocytes are sensitive to Se intoxication and there is a disparity in the immune system toxicity of inorganic and organic forms of Se administered via the drinking water, inorganic Se being more toxic.

Fumonisin hepatotoxicity is reduced in mice carrying the human tumour necrosis factor alpha transgene

Our previous studies have indicated that tumour necrosis factor alpha (TNFalpha) is involved in fumonisin B1 (FB1)-induced toxic responses. To investigate the role of TNFalpha in FB1 toxicity further we employed male transgenic mice expressing human TNFalpha gene (TG) and their wild-type equivalent C57BL/6 (WT). It was hypothesized that TG animals would have enhanced response to FB1. Repeated subcutaneous treatment of animals with 2.25 mg/kg per day of FB1 for 5 days caused minimal changes in body weight, organ weights, blood cell counts, and TNFalpha levels in plasma 1 day after the last injection. The mRNA for TNFalpha in liver increased in both TG and WT after FB1 treatment, providing evidence that FB1 induces hepatic TNFalpha expression. Liver and kidney lesions were found in TG after FB1 treatment; however, liver lesions seen in FB1-treated TG were considerably less than those observed in WT. The decreased hepatotoxicity in TG after FB1 treatment correlated with plasma concentrations of alanine aminotransferase and aspartate aminotransferase. Free sphinganine levels increased significantly in both the liver and kidney of WT and TG mice treated with FB1. The increase of free sphinganine in the liver from TG mice was 40% less than in WT mice and paralleled the changes in serum liver enzymes. Regional brain neurotransmitters and their metabolites were increased to a similar extent by FB1 in both WT and TG mice. Since the data did not support the original hypothesis, we investigated the levels of NFkappaB in liver. The cytosolic NFkappaB was significantly higher in TG compared with WT. Induction of NFkappaB, caused by increased endogenous production of TNFalpha, is a possible explanation of decreased FB1 hepatotoxicity in TG. The results suggest a protective role for NFkappaB in FB1-induced liver damage.

Increase in dopamine metabolites in murine striatum after oral exposure to inorganic but not organic form of selenium

Selenium (Se) is an essential as well as a toxic trace element. Se intoxication has been reported in both livestock and humans. The central nervous system is sensitive to Se poisoning; exposure to Se causes blind staggers in cattle, poliomyelomalacia in pigs, and nervous system disorders in humans. Differences in neurotoxicity between inorganic and organic Se have been demonstrated. In this study, groups of five male BALB/c mice each were administered sodium selenite or selenomethionine in drinking water ad libitum at 0, 1, 3, and 9 ppm as Se for 14 days. At the end of Se exposure, their brains were removed and dissected into different regions. The concentration of norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxyindolacetic acid (5-HIAA) were determined in each brain region. Food and water consumption and body weight gain were significantly decreased in the group treated with the highest concentration of sodium selenite. In mice administered sodium selenite at 3 and 9 ppm, DOPAC was significantly higher in the striatum than in the control group. The striatal HVA was also increased in the group treated with 3 ppm Se; the DA showed a similar pattern, but the increase was not statistically significant. No alterations of NE, 5-HT, or 5-HIAA levels were detected in any brain region of mice treated with sodium selenite. No significant differences in any parameter among the groups treated with selenomethionine were observed indicating that inorganic Se was more neurotoxic than organic Se via drinking water. The alterations of DA metabolites by inorganic Se in DA-rich striatum suggested a Se-specific increased neural activity of dopaminergic pathways. Results may be useful in further elucidation of neurotoxicity of Se and in establishing a safe level of intake for this element.

New approach for measurement of sympathetic nervous abnormality in conscious, spontaneously hypertensive rats

We previously reported a highly sensitive chemiluminescence high-performance liquid chromatographic method to determine catecholamines in plasma. In this study, we employed this method to measure the cardiac function and plasma norepinephrine (NE) concentration in conscious rats. Benidipine, 1,4-dihydropyridine calcium antagonist (4 mg/kg), and beta-blocker (propranolol, 30 mg/kg) were administered orally to conscious spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats, and blood pressure, heart rate and plasma NE levels were measured. Plasma NE concentration was used as an index of sympathetic nervous system activity in conscious rats. The basal plasma NE levels were significantly higher in SHRs than in WKY rats (P<0.05), indicating the activity of the basal sympathetic nervous system in SHRs was elevated. The sensitivity of the baroreflex-mediated sympathetic nervous response was reduced in SHRs as compared to that in WKY rats. The concomitant administration of benidipine and a beta-blocker decreased heart rate without affecting the baroreflex-mediated sympathetic nervous response, indicating that propranolol might suppress mainly the cardiac beta-adrenoceptor. The present study suggested the high activity of the basal sympathetic nervous system and the reduced response of the baroreflex-mediated sympathetic nervous system in SHRs compared to WKY rats in the conscious condition.

Fumonisin toxicity in a transgenic mouse model lacking the mdr1a/1b P-glycoprotein genes

The toxicity of fumonisin B(1) (FB(1)) was investigated in male mdr1a/1b double knockout (MDRK) mice, lacking the drug-transporting P-glycoproteins. These transgenic animals are deficient in their blood:brain barrier and accumulate different drugs in brain and other tissues. The MDRK and their wild-type counterparts, FVB mice, were injected subcutaneously with 2.25 mg/kg per day of FB(1) for 5 days and sampled one day after the last treatment in a protocol that has resulted in marked hepatic and renal damage in other strains. FB(1) caused liver enlargement in both FVB and MDRK. Hematological parameters were not affected in either strain. Plasma levels of alanine aminotransferase and aspartate aminotransferase, measures of liver damage, were increased by FB(1) in both FVB and MDRK mice. Histopathological evaluation of liver corroborated this finding. Kidney lesions were induced by FB(1) in both types of mice. Concentrations of free sphingosine and sphinganine increased in liver and kidney of both strains after the FB(1) treatment, although the increase in liver sphingoid bases was half as much in MDRK as compared to FVB. The levels of sphinganine-containing complex sphingolipids were increased in kidney. The levels of sphingosine-containing complex sphingolipids in kidney were unaffected by FB(1) treatment but were significantly lower in control MDRK than in FVB mice. The levels of neurotransmitters and their metabolites were similarly affected in both strains by FB(1), suggesting no influence of disrupted blood:brain barrier on FB(1)-induced neurotoxicity. In both strains, the liver mRNA for tumor necrosis factor alpha was increased; however, the increase was statistically significant only in FVB. It was apparent that mice deficient in P-glycoprotein do not exhibit greater sensitivity to FB(1), the cellular or brain transport of FB(1) appears to be independent of this multidrug transporting system.

Role of fracture hematoma and periosteum during fracture healing in rats: interaction of fracture hematoma and the periosteum in the initial step of the healing process

To study the mechanisms of fracture healing, we investigated the interaction between fracture hematoma and periosteum during the early phase of fracture healing in rats. Experimentally induced fractures of the tibia in untreated rats were compared histologically with such fractures in rats in which either the bone marrow or the periosteum had been removed. The extent of periosteal cell proliferation and chondrogenesis in the fracture hematoma was evaluated on experimental days 3, 6, 10, and 14. On day 3, periosteal cell proliferation at the tibial fracture site was decreased in the bone marrow-removed rats compared with the proliferation in untreated rats. Little chondrogenesis in the fracture hematoma was seen through day 6 in the periosteum-removed rats. These results suggest that the periosteum is important for mediating the primary steps of chondrogenesis and enchondral ossification in the fracture hematoma and that the fracture hematoma may be essential for periosteal cell proliferation during fracture healing.

Detection of carbapenemase-producing Acinetobacter baumannii in a hospital

Acinetobacter baumannii strains resistant to both imipenem (IPM) and ceftazidime (CAZ) were isolated from 1994 through 1996 at Gunma University Hospital. Nine isolates from different inpatients were examined for carbapenem-hydrolyzing activity and for the carbapemase gene bla(IMP) by the PCR method. All nine isolates were carbapenemase-producing strains that hydrolyzed IPM and that harbored bla(IMP). The bla(IMP) gene was transmissible by conjugation to an IPM-susceptible recipient strain of A. baumannii and conferred resistance to IPM, CAZ, cefotaxime (CTX), ampicillin (AMP), and piperacillin (PIP). Either intermediate or high-level resistance to amikacin (AMK) was transferred from two and five strains, respectively, concomitantly with bla(IMP), and gentamicin (GEN) resistance was also transferred in one instance of high-level AMK resistance. Comparative examination of clinical isolates for resistance patterns to nine drugs, IPM, CAZ, CTX, aztreonam, AMP, PIP, AMK, GEN, and norfloxacin, in addition to pulsed-field gel electrophoresis patterns with NotI-digested genomic DNA, confirmed nosocomial transmission of infections involving carbapenemase-producing A. baumannii strains.

Automatic semi-microcolumn liquid chromatographic determination of catecholamines in rat plasma utilizing peroxyoxalate chemiluminescence reaction

A fully automated and highly sensitive method with a semi-microcolumn liquid chromatography system for the determination of rat plasma catecholamines (CAs) was developed. Automated on-line extraction of CAs in diluted plasma using a precolumn packed with strong acidic cation exchange resin was coupled with separation of CAs on a semi-microcolumn (250 x 1.5 mm id). fluorogenic derivatization with ethylenediamine and finally postcolumn peroxyoxalate chemiluminescence detection utilizing bis[2-(3,6,9-trioxadecanyloxycarbonyl)-4-nitrophenyl]oxalate (TDPO) and hydrogen peroxide. The detection limits were 0.91, 0.36 and 1.1 fmol for norepinephrine (noradrenaline), epinephrine (adrenaline) and dopamine, respectively, at a signal-to-noise ratio of 3. A good linearity of the calibration curve for each CA was observed in the range of 5.0 to 500 fmol for each CA using N-methyldopamine (N-MeDA) as an internal standard. The RSD for the proposed method (n = 5) were 3.7-9.5% for the intra-day assay and 6.6-10.0% for the inter-day assay. The volume of rat plasma required for the determination of CAs was 10 microliters.

Treatment of ununited fracture of the hook of hamate by low-intensity pulsed ultrasound: a case report

A patient presented 4 months after sustaining a fracture of the hook of hamate. X-rays and computed tomography scanning of the carpal tunnel confirmed the presence of an ununited fracture. Low-intensity ultrasound was applied to the fracture site. After 4.5 months of exposure to ultrasound, union was confirmed by both x-rays and computed tomography scanning of the carpal tunnel. (J Hand Surg 2000; 25A:77-79.

[Putaminal signal hypointensity on T2 weighted MR image in a patient with corticobasal degeneration]

In the course of a 74-year-old woman with corticobasal degeneration (CBD), bilateral putaminal signal hypointensity appeared on T2 weighted MR image. This right-handed woman noticed progressive difficulty in writing and using chopsticks during two years. Neurological examination in February 1998 showed apraxia, rigidity, akinesia and myoclonus, which were more marked in the right hand side. MRI revealed atrophy of the left frontotemporal lobes. These findings were compatible to CBD. Her symptoms progressed slowly. On re-admission due to aspiration pneumonia in December 1998, she showed difficulty in swallowing and walking in addition to the signs and symptoms described above. MRI revealed bilateral putaminal signal hypointensity on T2 weighted image. In the literature, totally 9 cases in 2 reports showed similar putaminal signal hypointensity. Although this finding is unusual in CBD, advanced degenerative process in the putamen might have induced this change due possibly to the accumulation of iron secondary to the nerve cell loss.

Altered dopamine turnover in murine hypothalamus after low-dose continuous oral administration of aluminum

Aluminum, a known neurotoxic substance, has been suggested as a possible contributing factor in the pathogenesis of Alzheimer's disease. Ground-water pollution by aluminum has been recently reported. In the current study groups of 5 male BALB/c mice were administered aluminum ammonium sulfate in drinking water ad libitum at 0, 5, 25, and 125 mg/L aluminum for 4 weeks. At the termination of aluminum exposure, their brains were removed and dissected into cerebrum, cerebellum, medulla oblongata, midbrain, corpus striatum, and hypothalamus. The concentration of norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA), were determined in each brain area. DA, DOPAC, and HVA levels were lower in the hypothalamus of aluminum-treated mice, most notably in the low-dose group, as compared with control. No marked alterations in NE, 5-HT, and 5-HIAA levels were detected in any brain region. Changes in the concentration of DA and its metabolites measured in the hypothalamus suggest an inhibition of DA synthesis by aluminum.

Modulation of tumor necrosis factor alpha expression in mouse brain after exposure to aluminum in drinking water

Aluminum, a known neurotoxic substance and a ground-water pollutant, is a possible contributing factor in various nervous disorders including Alzheimer's disease. It has been hypothesized that cytokines are involved in aluminum neurotoxicity. We investigated the alterations in mRNA expression of tumor necrosis factor alpha (TNFalpha), interleukin-1beta (IL-1beta), and interferon gamma (IFNgamma), cytokines related to neuronal damage, in cerebrum and peripheral immune cells of mice after exposure to aluminum through drinking water. Groups of male BALB/c mice were administered aluminum ammonium sulfate in drinking water ad libitum at 0, 5, 25, and 125 ppm aluminum for 1 month. An additional group received 250 ppm ammonium as ammonium sulfate. After treatment, the cerebrum, splenic macrophages and lymphocytes were collected. The expression of TNFalpha mRNA in cerebrum was significantly increased among aluminum-treated groups compared with the control, in a dose-dependent manner. Other cytokines did not show any aluminum-related effects. In peripheral cells, there were no significant differences of cytokine mRNA expressions among treatment groups. Increased expression of TNFalpha mRNA by aluminum in cerebrum may reflect activation of microglia, a major source of TNFalpha in this brain region. Because the aluminum-induced alteration in cytokine message occurred at aluminum concentrations similar to those noted in contaminated water, these results may be relevant in considering the risk of aluminum neurotoxicity in drinking water.

Amelioration by KRP-297, a new thiazolidinedione, of impaired glucose uptake in skeletal muscle from obese insulin-resistant animals

We examined the effect of KRP-297, a new thiazolidinedione derivative, on glucose uptake in the soleus muscle of two animal models of insulin resistance that show moderate (ob/ob mice) and severe (db/db mice) hyperglycemia. Insulin-stimulated 2-deoxyglucose (2DG) uptake in soleus muscle was 53.8% lower in ob/ob mice versus lean mice (P < .05). When administered to ob/ob mice, KRP-297 (0.3 to 10 mg/kg) decreased plasma glucose and insulin levels and improved the impaired insulin-stimulated 2DG uptake in soleus muscle in a dose-dependent manner. Soleus muscle from db/db mice exhibited defects in both basal (35.0% decrease, P < .01) and insulin-stimulated (50.5% decrease, P < .01) 2DG uptake. These defects were improved by treatment with KRP-297 (0.3 to 10 mg/kg). Moreover, KRP-297 prevented severe hyperglycemia and the marked decrease in pancreatic insulin content in db/db mice. These results suggest that KRP-297 treatment is useful to prevent the development of diabetic syndromes in addition to ameliorating the impaired glucose transport in skeletal muscle.

Determination of aspartic acid enantiomers in bio-samples by capillary electrophoresis

Enantiomeric separation and detection of D,L-aspartic acid (Asp) derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) by capillary electrophoresis (CE) using modified cyclodextrins as chiral selectors was studied. Heptakis(2,3, 6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) was most effective for enantiomeric separation of NBD-D,L-Asp with optimum conditions of 30 mM TM-beta-CD in 50 mM phosphate buffer (pH 4.0) and the limit of detection (LOD) attained was 100 nM for each enantiomer. The method proposed in the present study was convenient for both D- and L-Asp determination since the other amino compounds migrated differently and D-Asp in bio-samples such as rat pineal gland and foods was determined with a simple sample pretreatment and a short analysis run time.

Simultaneous automatic determination of catecholamines and their 3-O-methyl metabolites in rat plasma by high-performance liquid chromatography using peroxyoxalate chemiluminescence reaction

A highly specific and sensitive automated high-performance liquid chromatographic method for the simultaneous determination of catecholamines (CAs; norepinephrine, epinephrine, and dopamine) and their 3-O-methyl metabolites (normetanephrine, metanephrine, and 3-methoxytyramine) is described. Automated precolumn ion-exchange extraction of diluted plasma is coupled with HPLC separation of CAs and their 3-O-methyl metabolites on an ODS column, postcolumn coulometric oxidation, fluorescence derivatization with ethylenediamine, and finally peroxyoxalate chemiluminescence reaction detection. The detection limits were about 3 fmol for norepinephrine, epinephrine, and dopamine, 5 fmol for normetanephrine, and 10 fmol for metanephrine and 3-methoxytyramine (signal-to-noise ratio of 3). Fifty microliters of rat plasma was used and 4-methoxytyramine was employed as an internal standard. The relative standard deviations for the method (n = 5) were 2.5-7.6% for the intraday assay and 6.3-9.1% for the interday assay. The method was applicable to the determination of normetanephrine and metanephrine in 50 microl of rat plasma.

Low intensity pulsed ultrasound exposure increases prostaglandin E2 production via the induction of cyclooxygenase-2 mRNA in mouse osteoblasts

Both prostaglandin E2 (PGE2) and low intensity pulsed ultrasound (U/S) exposure have been reported to accelerate fracture repair. We hypothesized that these two pathways are interactive. To verify this hypothesis, we examined the regulation of PGE2 production by U/S exposure (sine wave of 1.5MHz repeating at 1kHz, 30mW/cm2, 20 minutes) in mouse osteoblastic cell line, MC3T3-E1. The production of PGE2 in osteoblasts was augmented by U/S, which was threefold at 60 min. in comparison with unexposed samples. Then we evaluated the expression of cyclooxygenase-2 (COX-2) mRNA, which is a critical enzyme for PGE2 production. U/S rapidly up-regulated the expression of COX-2 mRNA in a time dependent manner. In addition, PGE2 production by U/S was drastically suppressed by a selective inhibitor of COX-2. These results provide strong evidence that PGE2 production in osteoblasts is dependent upon the induction of COX-2 mRNA expression by U/S and offer a mechanistic insight into how U/S accelerates fracture repair.

(3-substituted benzyl)thiazolidine-2,4-diones as structurally new antihyperglycemic agents

A series of 3-[(2,4-dioxothiazolidin-5-yl)methyl]benzamide derivatives was prepared as part of a search for antidiabetic agents. A structure-activity relationship study of these compounds led to the identification of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluorome thyl)-phenyl]methyl]benzamide (KRP-297) as a candidate drug for the treatment of diabetes mellitus.

Region-specific decrease of dopamine and its metabolites in brains of mice given ergotamine

Ergot alkaloids (EA) such as the ergopeptine alkaloid ergotamine (ET) are adrenergic, dopaminergic, and serotonergic agents. The objective of this experiment was to investigate regional brain neurotransmitter alterations caused by EA. Male BALB/c mice were treated s.c. daily with ergotamine tartrate for 10 d at 0 (saline), 0.4, 2, 10, or 50 mg/kg body weight. Twenty-four hours after the last treatment, animals were sacrificed and brains dissected. Regional concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT), and metabolites 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindole-3-acetic acid (5-HIAA) were measured by high-performance liquid chromatography (HPLC). Moreover, selected organ weights and plasma prolactin (PRL) were determined. Dopamine concentration was significantly reduced by ET at all doses in the striatal and hypothalamic regions. A reduction of the DA metabolite HVA occurred in striatum at only the highest dose, whereas in the hypothalamus both HVA and DOPAC were markedly reduced. Concentrations of NE, MHPG, 5-HT, and 5-HIAA were not affected by treatment in these regions. In the cerebellum, MHPG was significantly elevated at the 50 mg/kg dose. No effect of treatment was observed in the cerebrum, medulla, and midbrain. Further, no treatment-related differences in plasma PRL and organ weights other than a significant liver weight decrease at intermediate doses were found. Therefore, the effects of ET were predominantly upon DA metabolism in the corpus striatum and hypothalamus. The reductions in DA, HVA, and DOPAC indicate decreased DA synthesis.

Establishment of a non-union model using muscle interposition without osteotomy in rats

Many attempts have described a standard experimental model for fracture non-union in laboratory conditions, but the majority of them produced after an experimental osteotomy, so it is different from clinical disturbed fracture healing. The purpose of this study is to establish a standard method for producing fracture non-union with only muscle interposed into the fracture site in rats. Bilateral tibial fractures were made in forty-eight male Wister rats by three point bending and we surgically interposed the distal end of the tibialis anterior muscle into the fracture site. They were sacrificed at 1, 2, 3, 6, 12, 24, 48, and 96 weeks after fracture. The rentgenograms were obtained, and the fractured tibias were harvested in each time period and investigated histologically and immunohistochemically. The rentgenogram at six weeks, in the non-union rats, showed abundant callus at each end of the fracture fragments, but no bridging callus. The histological finding with hematoxylin and eosin, at this point, shows no bridging soft callus, and small isolated regions of cartilage were observed only where the bone was not covered by the muscle. The proliferating cell nuclear antibody immunostaining which is associated with cell proliferation was abruptly lost in chondrocytes at two weeks. This early disappearance of chondrocytes without endochondral ossification may be a significant etiological factor in the development of a non-union. This non-union model is technically simple and reproducible, and dose not require periosteal stripping or surgical osteotomy to produce an artificial bone gap.

[Anatomic variants of the cystic duct and cysticohepatic junction: diagnosis with MR cholangiography]

The cystic duct are variable in length, course and site of termination. A knowledge of the variable anatomy of the cystic duct and cysticohepatic junction is important in biliary surgery, because failure to recognize anatomic variations may result in a significant ductal injury. Magnetic resonance cholangiography (MRC) is a recently developed technique that demonstrates the biliary tree noninvasively and without injection of contrast material. Anatomic variants of the cystic duct and cysticohepatic junction that may increase the risk of bile duct injury in biliary surgery are frequently identified with MRC. MRC will be a noninvasive and a useful technique in the diagnosis of anatomic variants of the cystic duct and cysticohepatic junction.

Fumonisin B1-induced increases in neurotransmitter metabolite levels in different brain regions of BALB/c mice

Fumonisin B1, a toxin produced by Fusarium moniliforme, causes a variety of diseases in animals, including those involving the central nervous system, such as equine leukoencephalomalacia (ELEM). The changes of biogenic amines may reflect fumonisin B1 neurotoxicity. It was previously reported that consumption of feed contaminated with Fusarium moniliforme cultures produced an elevation of 5-hydroxyindoleacetic acid (5-HIAA), the major metabolite of 5-hydroxytryptamine (5-HT), in whole rat brains. In a subsequent study from the same laboratory, rats given fumonisin B1 orally for 4 weeks showed no changes in neurotransmitter levels of the whole brain. In the current study, groups of five male BALB/c mice were injected with fumonisin B1 subcutaneously at doses of 0, 0.25, 0.75, 2.25, 6.75 mg kg-1 body weight daily for 5 days. One day after the last treatment, their brains were dissected into cerebrum, cerebellum, medulla oblongata, midbrain, corpus striatum and hypothalamus. Levels of norepinephrine (NE), dopamine (DA), DA metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and 5-HT and 5-HIAA were determined. A significant elevation of HVA was observed in mice treated with high doses of fumonisin B1 in most brain regions. In striatum, a decrease of 5-HT was observed by the fumonisin B1 treatment. Ratios of neurotransmitters to metabolites such as HVA/DA and 5-HIAA/5-HT were elevated in several brain regions of the treated groups. An accumulation of neurotransmitter metabolites is suggestive of increased neuronal activity or interference with their efflux from cells.

[Evaluation of the cystic duct and cysticohepatic junction with MR cholangiography: comparison of various techniques and clinical evaluation with respiratory-triggered three-dimensional multislab technique]

The purpose of this study was to evaluate depiction of the cystic duct and cysticohepatic junction by MR cholangiography (MRC). In 10 volunteers, MR cholangiograms were obtained by breath-hold two-dimensional (2D), respiratory-triggered 2D, respiratory-triggered three-dimensional (3D) single slab, and 3D multislab techniques. The images then were compared qualitatively. MRC using the respiratory-triggered 3D multislab techniques was evaluated as better than the other techniques, and was performed in 35 patients. Depiction of the anatomy of the cystic duct and cysticohepatic junction were evaluated. In 8 of 35 patients, MRC images were compared with those obtained by endoscopic retrograde cholangiography (ERC). The cystic duct and cysticohepatic junction were visualized adequately in 93% of volunteers and patients by the respiratory-triggered 3D multislab technique. Anatomic variations in the cystic duct and cysticohepatic junction were evaluated. The frequency of anatomic variations was the same as previously reported. The anatomic evaluations obtained by MRC were correlated closely with those obtained by ERC in 8 patients. In conclusion, MRC with the respiratory-triggered 3D multislab techniques is useful in evaluation of the cystic duct and cysticohepatic junction.

X-ray analysis of DNA dodecamer containing 2'-deoxy-N6-methoxyadenosine

Oxyamines have been known as a mutagen which attacks amino groups of DNA bases. It is expected that the modified adenine derivative has a tautomer which can form a stable base pair not only with thymine but also with cytosine. For establishing such tautomerization mutagenesis, we have solved a crystal structure of DNA dodecamer containing 2'-deoxy-N6-methoxyadenosine. It is shown that the N6-methoxyadenine takes a imino form to form a Watson-Crick type pairing with cytosine in the DNA duplex.

Novel metallo beta-lactamase mediated by a Shigella flexneri plasmid

Novel carbapenem-hydrolyzing beta-lactamase (newly named MET-1) encoded on a transferable plasmid pMS390 from Shigella flexneri JS19622 was purified. The molecular weight was 28,000 by SDS-PAGE and the isoelectric point was higher than 9.3. This beta-lactamase favorably hydrolyzed classical cephalosporins and oxyimino-cephalosporins rather than penicillins and carbapenems, but did not hydrolyze monobactams. The enzymatic activity was inhibited by EDTA, and the enzyme was found to contain two moles of zinc per mole of enzyme protein by means of atomic absorption spectrophotometry. These results indicated that the enzyme is a zinc beta-lactamase which differs from known metallo beta-lactamases, especially in its cephalosporinase-type substrate profile.

Tumor necrosis factor-alpha as a contributor in fumonisin B1 toxicity

Fumonisin B1 is a toxic product of Fusarium moniliforme, which inhibits ceramide synthase, leading to accumulation of free sphingoid bases. Despite its known biochemical action, the mechanism of toxicity is not fully understood. Male BALB/c mice were injected subcutaneously with 0 to 6.75 mg/kg/day of fumonisin B1 for 5 days. One day after the last treatment, spleens were collected, and peritoneal macrophages were obtained from separate groups after an intraperitoneal injection of thioglycolate broth. Peripheral leukocyte counts were increased and kidney weights were decreased by fumonisin B1 treatment. Presence of apoptotic cells in the liver and kidney of treated mice was confirmed by enzymatic immunoassay. Macrophages cultured with lipopolysaccharide indicated an increased secretion of tumor necrosis factor-alpha (TNF-alpha) but not of interleukin-1alpha. No effect was seen on interferon-gamma production when splenocytes were incubated with concanavalin A. Elevation of leukocyte and reticulocyte counts was abrogated by pretreatment with anti-TNF-alpha antibody before a single dose of fumonisin B1 (25 mg/kg), supporting the hypothesis that the fumonisin B1 toxicity involves TNF-alpha. Cultures of J774A.1 cells, when treated with fumonisin B1, produced TNF-alpha in vitro. Results indicate that fumonisin B1 toxicity may involve secretion of TNF-alpha by TNF-alpha-producing cells without altering interleukin-1alpha or interferon-gamma. The influence on TNF-alpha-production may be a contributing factor to fumonisin B1-induced apoptosis and other observed toxic effects in animals.

Immunochemical distinction of Aloe vera, A. arborescens, and A. chinensis gels

Verectin antiserum raised in white rabbits was immunoprecipitated with the Aloe vera nondialysable fraction. Analysis of the immunoprecipitation revealed that verectin accounted for about 1.25% of the total proteins in the nondialysable fraction of Aloe vera gel. The verectin antibody showed differential immunoreactivities against nondialysable fractions of A. arborescens, A. chinensis, and A. vera: 1) an immunopreciptin line was formed against the fraction of A. vera, but not against those of A. arborescens and A. chinensis gel in an Ouchterlony double immunodiffusion test and 2) an immunopositive band was detected in the A. vera and A. chinensis nondialysable fractions but not in that of A. arborescens in immunoblotting. These findings indicate that the verectin antibody can be used to distinguish Aloe materials.

[Specific modulation of vascular smooth muscle cell functions by docosahexaenoic acid]

There are increasing evidences that fish oil-enriched diets attenuate the progression of several types of human and experimental renal, intestinal and cardiovascular disorders including hypertension. Docosahexaenoic acid (DHA) may be one of the active biological component. We previously reported that dietary DHA suppressed the progression of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). The purpose of this study was to clarify the in vitro effect of DHA on vascular smooth muscle cell functions such as cell growth, hypertrophy, NO release, and intracellular Ca+2 dynamics which involves in the regulatory mechanisms of vascular tone. Addition of DHA to the culture medium of aortic smooth muscle cells isolated from SHRSP and normotensive Wistar Kyoto rats (WKY) had no significant effects on the cell growth, and cell hypertrophy induced by angiotensin II as measured by flow cytometer. DHA did not have a significant effect on interleukin-1 beta (10 ng/ml)-induced nitric oxide release from smooth muscle cells of SHRSP. However, the treatment of smooth muscle cells with DHA (30 microM) for 2 days significantly suppressed the increase in the intracellular Ca2+ concentration induced by 5-hydroxytryptamine, angiotensin II, depolarizing concentration of KCl, but not by thapsigargin. This suppression seems to be due to the suppression of Ca2+ influx, as determined by Mn2+ influx experiment. These results suggest that DHA specifically suppresses receptor-mediated Ca2+ influx in smooth muscle cells. This may be one of the mechanisms by which dietary DHA prevents the development of hypertension in SHRSP.

[Preoperative evaluation for volume reduction surgery of pulmonary emphysema using MRI: usefulness of HASTE (half-Fourier single-shot turbo SE) sequence during deep respiration]

Volume reduction surgery has recently been an important surgical procedure for patients with severe pulmonary emphysema. We compared the sagittal and coronal images taken by the HASTE sequence with those obtained by turbo FLASH during deep breathing and with CT images obtained under deep inspiration. Clear images were obtained from both sequences, without cardiac or respiratory motion artifacts. The emphysematous areas were demonstrated as low signal intensity areas, as in CT images. The ratio of signal intensity in the expiratory phase to that in the inspiratory phase was lower than that of volunteers in the HASTE sequence. The HASTE sequence provides useful information about respiratory movement as well as about changes in the pulmonary parenchyma when used for preoperative examination.

Dual recognition of a human cytotoxic T-cell clone for melanoma antigens

It is well known that tumor-specific CTLs have a crucial role in the elimination of tumors and that different CTL populations recognize tumor antigens in MHC-restricted and MHC-unrestricted manners. We have established two alpha beta CTL clones that recognize melanoma antigens in both human lymphocyte antigen (HLA)-A2-restricted and HLA-unrestricted manners. Flow cytometry analysis showed that these CTL clones carry CD3, CD8, and alpha beta T-cell receptor (TCR) and express low levels of CD56. In contrast, these CTL clones do not express CD16, indicating that they do not contain natural killer cells. TCR analysis of these CTL clones using an anchored PCR method revealed that each clone carries a single alpha beta TCR. Both CTL clones contained the same Valpha and Vbeta gene segments although they carried different Jalpha and Jbeta gene segments. Taken together, these results confirm that CTL clones that carry a single alpha beta TCR recognize melanoma antigens in both HLA-A2-restricted and HLA-unrestricted manners. It is strongly suggested that the dual recognition of these CTL clones for the melanoma antigens is mediated by TCRs. The novel mechanism for antitumor immunity by these CTLs may be important in the effective elimination of tumors in vivo.

[Changes in cysteine sulfinic acid in rat brain under the experimental elevation of taurine content]

Excitatory sulfur amino acids (SAAs) seem to be important, because derangement of SAA metabolism has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Since the concentration of excitatory SAAs in the neural tissue is extremely low, their presence or absence has not been conclusive in the literature. I determined cysteine sulfinic acid (CSA), cysteic acid (CA), homocysteine sulfinic acid (HCSA) and homocysteic acid (HCA) in rat brain by high-performance liquid chromatography using a Shimazu HPLC system LC10. Among the 4 excitatory SAAs mentioned above, the peaks of CA, HCSA and HCA did not appear at the chromatographic retention time corresponding to that of the authentic compounds. Only the peak of CSA was identified by matching retention time with the external standard as well as consistent co-elution with the added authentic compound. Thus the existence of CSA was confirmed and its concentration was 9.18 +/- 3.54 pmol/mg wet weight. Although the other 3 excitatory SAAs were not detected in rat brain, their presence in human brain cannot presently be excluded, because the size of the amino acid pool in rat brain is not the same as that in human brain. I examined in rat brain whether the concentration of CSA would possibly change when taurine, the final product of the metabolic pathway of SAAs, is experimentally increased. The inhalation of nitrous oxide (N2O) and the thyroidectomy have both been known to give rise to the elevation of taurine in the central nervous system, the mechanism of which is reportedly due to the impairment of the folate cycle. The metabolic flow of the SAA pathway is increased as a result of slowing down of the folate cycle, the damage of which has been shown in the brain of N2O-inhaled rats and thyroidectomized rats as well as of patients with ALS. The concentration of CSA was significantly increased in the cerebrum and the brainstem of the N2O-inhaled rats and the thyroidectomized rats, and in the cerebellum of the latter. CSA, recently demonstrated as a neurotransmitter, has been reported to have neurotoxicity stronger than that of gultamate in cultured rat cerebral neurons. The measurement of excitatory SAAs, especially CSA in nervous tissue of ALS will be required, although relevance of excitatory SAAs to the pathogenesis of ALS is not certain at present.

Yolk sac tumor in a case of testicular feminization syndrome

A 17 month old who had been diagnosed as having testicular feminization syndrome (noted during inguinal herniorrhaphy) was operated on because of an abdominal mass that had a high serum level of alpha-fetoprotein. Histologically, the lesion was a yolk sac tumor. The alpha-fetoprotein level normalized within 2 months of the surgery, through the administration of adjunctive chemotherapy containing cisplatinum. The patient is disease-free 4 years postoperatively. When performing inguinal herniorrhaphy in a girl, the surgeon should be prepared to deal with testicular feminization syndrome. If gonadal neoplasm is deniable at the time of diagnosis, careful follow-up examinations are needed until completion of the development of secondary sex characteristics.

Portal blood flow in the presence or absence of diffuse liver disease: measurement by phase contrast MR imaging

BACKGROUND

In patients with diffuse liver disease, the portal flow dynamics change markedly in accordance with disease progression and would provide a useful index of progression of stage.

METHODS

Portal blood flow (PBF) was measured by phase contrast magnetic resonance imaging (MRI) in 21 patients with diffuse liver disease and 20 healthy volunteers. The MRI method was validated by a flow phantom study. The mean PBF could be measured in 6.8 min without breath-holding.

RESULTS

Doppler ultrasound measurements of PBF volume were obtained reproducibly in all the healthy volunteers and were shown to correlate with the MRI values (Doppler: 12.5 +/- 3.2 cm3/s, MRI: 12.0 +/- 3.3 cm3/s; mean +/- SD). The PBF volume of patients with chronic hepatitis showed no significant difference from that of the healthy volunteers. In patients with liver cirrhosis, the PBF volume ranged from 5.01 to 32.3 cm3/s. A significant increase in PBF volume was caused in one patient by massive intrahepatic shunting and a significant decrease was caused in two patients by massive extrahepatic shunting.

CONCLUSIONS

The measurement of PBF by phase contrast MRI is clinically useful in predicting intrahepatic or extrahepatic shunting in patients with liver cirrhosis, and may be of value in detecting the progression of stage in diffuse liver diseases.

Structural composition of hammerhead ribozymes

Eleven kinds of hammerhead ribozymes were designed and synthesized to investigate the structural composition of the complexes and to find suitable crystallization conditions, the substrate chains having been modified to prevent hydrolysis. Electrophoresis patterns indicated that the two strands except for the substrate chain form a binary complex and that they form a ternary complex when mixed with the substrate chain. Both complexes were crystallized. The crystal of the binary complex belongs to a Laue symmetry of 32 (space group of P321, P3(1)21, or P3(2)21) with cell dimensions of a = b = 53.4 and c = 59.4 A. The volume per one nucleotide allows the asymmetric unit to contain one binary complex. Our results suggest that the catalytic part forms a rigid ribozyme structure which induces a scissile reaction when the substrate is bound, in a similar manner to an enzyme protein.

X linked ocular albinism in Japanese patients

Thirteen affected Japanese male patients and 13 female carriers with X linked ocular albinism from seven families were examined to assess their clinical findings and to compare them with those of white and black patients. Affected Japanese patients had poor visual acuity, horizontal nystagmus, macular hypoplasia, and loss of stereopsis. Some affected patients had non-albinotic fundus with moderate pigmentation. The amount of pigment in the fundus varied among affected patients and appeared to be between that of the white and black patients. All affected patients had brown irides that show no translucency. Interestingly, two affected patients had megalocornea and a third affected patient had posterior embryotoxon. All female carriers exhibited good visual acuity, normal eye position, stereopsis, brown irides without translucency, and the typical mosaic pattern in the fundus. The pigmented iris and fundus made the correct diagnosis of these affected patients difficult. Nine affected patients (70%) had been diagnosed initially as having congenital nystagmus, with or without macular hypoplasia, until they were reviewed for this study.

Electrostatic potential in aminoacylation by aspartyl-tRNAs synthetase

Based upon the X-ray structures of complexes between tRNAAsp and aspRS including ATP or Asp-AMP, several electrostatic potentials were calculated by solving the Poisson-Boltzmann equation. The potentials indicate clearly that a Mg2+ ion is essential for binding of ATP and that aspartate is identified electrostatically. The alpha-carboxyl group is forced to contact with the alpha-phosphorus atom of ATP, suggesting its inversion to form an Asp-AMP. When the cognate tRNA is bound to the aspRS:Asp-AMP complex, the 3'-hydroxyl group is located in an electrostatically favorable position to transfer the amino acid as a class II aminoacylation.