Radical surgery for advanced gallbladder carcinoma

Forty-four patients with advanced gallbladder carcinoma (18 with stage pT3 and 26 with stage pT4 of the Union Internacional Contra la Cancrum classification) were aggressively managed by extended heptatic resection in 33 patients, bile duct resection in 28, pancreaticoduodenectomy in seven, gastrointestinal resection in eleven and portal vein resection and reconstruction in seven. Adjacent organ involvement was classified as follows: type I, hepatic involvement with or without gastrointestinal invasion (Ia, Ib); type II, bile duct involvement with or without gastrointestinal invasion (IIa, IIb); type III, hepatic and bile duct involvement with or without gastrointestinal invasion (IIIa, IIIb); type IV, gastrointestinal involvement without hepatic or bile duct invasion. Fourteen of 15 patients with type I tumours had a curative resection compared with seven of 26 with type III lesions (P < 0.0001). The surgical mortality rate was two of 15 patients with type I tumours, seven of 26 with type III tumours and nine of 44 for the whole group. The long-term survival rate after curative resection was four and two of 23 at 3 and 5 years respectively, significantly better than two and none of 21 at 1 and 2 years after non-curative resection (P < 0.01). The survival rate after curative resection for patients with type I tumours was four and two of 14 at 3 and 5 years respectively, significantly better than for other types (P < 0.05). This classification of advanced gallbladder carcinoma according to involvement of adjacent organs might be helpful in planning surgery for this condition; in particular, type I tumours should be treated by a radical surgical procedure to achieve a favourable outcome.

Structural basis for IL-4 receptor phosphopeptide recognition by the IRS-1 PTB domain

We present the NMR structure of the PTB domain of insulin receptor substrate-1 (IRS-1) complexed to a tyrosine-phosphorylated peptide derived from the IL-4 receptor. Despite the lack of sequence homology and different binding specificity, the overall fold of the protein is similar to that of the Shc PTB domain and closely resembles that of PH domains. However, the PTB domain of IRS-1 is smaller than that of Shc (110 versus 170 residues) and binds to phosphopeptides in a distinct manner. We explain the phosphopeptide binding specificity based on the structure of the complex and results of site-directed mutagenesis experiments.

[Immunohistochemical study of PCNA, p53 gene product and c-erbB-2 gene product in endometrial carcinoma]

I have investigated 84 endometrial specimens (from 15 cases of normal endometrium, 20 cass of hyperplasia and 49 cases of endometrial carcinoma) to determine the relationship between three proteins (proliferating cell nuclear antigen (PCNA), p53 gene product and c-erB-2 gene product) and endometrial carcinoma by immuno-histochemical staining. In 49 cases of endometrial carcinoma, the positive rates for PCNA, p53 protein (mutant type) and c-erbB-2 protein were 65.3%, 59.2% and 22.4%. I could not find the expression of p53 protein besides endometrial carcinoma. And I could find the expression of c-erbB-2 protein in 11 cases of endometrial carcinoma and 1 case of atypical hyperplasia, but not in normal endometrium. p53 protein was more common in such a case, as with lymphnode metastasis, deep myometral invasion and undifferentiated adenocarcinoma. c-erbB-2 was also more common in a case with deep myometrial invasion. In conclusion, PCNA, p53 protein and c-erbB-2 protein are related to the proliferation of endometrial carcinoma. So they can be useful factors in making the prognosis.

Proton magnetic resonance spectroscopy on childhood-onset dentatorubral-pallidoluysian atrophy (DRPLA)

To evaluate brain dysfunction of childhood-onset dentatorubral-pallidoluysian atrophy (DRPLA), three children with progressive myoclonus epilepsy, who were diagnosed as having DRPLA by DNA analysis, for the first time, underwent a study of proton magnetic resonance spectroscopy (1H-MRS). 1H-MRS obtained from both the parietal and basal ganglia regions disclosed markedly reduced ratios of N-acetylaspartate to both choline and creatine. Especially regarding the basal ganglia region, the latter (ratio of N-acetylaspartate to creatine) closely correlated to severity of genetic abnormality, i.e. number of expanded CAG repeats, suggesting that the degree of neuronal loss in the region strongly depends on genetic factors. 1H-MRS must be a valuable tool to clarify the pathophysiology of DRPLA.

A point mutation within each of two ATP-binding motifs inactivates the functions of elongation factor 3

We have investigated how point mutations in the two ATP-binding motifs (G(463)PNGCGK(469)ST and G(701)PNGAGK(707)ST) of elongation factor 3 (EF-3) affect ribosome-activated ATPase activity of EF-3, polyphenylalanine synthesis, and growth of Saccharomyces cerevisiae. The point mutation impaired the ribosome-activated ATPase activity of EF-3, when glycine(463 and 701) and lysine(469 and 707) were replaced with valine and arginine, respectively. Thus, each glycine and lysine residue in both ATP-binding motifs is indispensable for EF-3's binding with ATP and the ensuing generation of ribosome-activated ATPase activity. Additionally, the mutant EF-3s did not catalyze polyphenylalanine synthesis in vitro when each glycine(463 and 701) was replaced with valine. The mutant EF-3s did not support cell growth in TEF3-disrupted S. cerevisiae, when each lysine(469 and 707) and glycine(463) was replaced with arginine and valine, respectively. Thus, each of the two ATP-binding motifs of EF-3 is indispensable for the ribosome-activated ATPase activity of EF-3, which is required for protein synthesis and cell growth in S. cerevisiae.

Persistence of hepatitis C virus RNA in established human hepatocellular carcinoma cell lines

The persistence of the viral RNA of hepatitis C virus (HCV) was examined in 13 hepatocellular carcinoma (HCC) and two hepatoblastoma cell lines by reverse transcription followed by the polymerase chain reaction (RT-PCR). HCV RNA was detected in three HCC lines (JHH-1, JHH-4, and JHH-6) and negative-strand viral RNA was found in JHH-4, indicating that there is a putative replicative intermediate of HCV in JHH-4 cells. To rule out the possibility of contamination, the partial nucleotide sequences of HCV-specific PCR products of these three cell lines were determined. The clone from JHH-1 belonged to genotype 1 (1a or 1b), and the clones from JHH-4 and JHH-6 belonged to genotype 2b, but their sequences differed from each other. These cell lines may be useful for studies related to HCV.

Mechanisms of interleukin-2-induced hepatic toxicity

Interleukin 2 (IL-2) mediates the regression of metastatic cancer, but its clinical use is limited by associated toxicities including hepatic dysfunction. To determine the mechanism for IL-2-induced hepatic dysfunction, we hypothesized that IL-2 activation of Kupffer cells causes leukocyte-endothelial adhesion and decreases hepatic sinusoidal blood flow. C57BL/6 mice were given injections of latex particles and prepared for intravital hepatic microscopy 2 h after i.p. IL-2 administration. Liver tissue was also prepared to quantitate hepatic tumor necrosis factor (TNF) mRNA and processed for light and electron microscopy. Phagocytosing Kupffer cells and leukocytes adherent to the endothelium were counted, and surface sinusoidal blood flow was quantitated. Kupffer cell activity was quantitated as the ratio of phagocytosing Kupffer cells to sinusoidal blood flow. IL-2 significantly increased Kupffer cell activity (0.56 +/- 0.05 for controls versus 0.84 +/- 0.05 for IL-2), significantly caused leukocyte-endothelial adhesion (26.7 +/- 7.9 for controls versus 87.0 +/- 27.6 for IL-2, WBC/mm2 endothelial surface), and significantly decreased the number of sinusoids containing blood flow per microscopic field (6.66 +/- 0.15 for controls versus 5.79 +/- 0.13 for IL-2) without causing changes in systemic hemodynamic parameters. In IL-2 treated livers, light and electron microscopy showed the constriction of sinusoids associated with swollen or ruptured mitochondria, which was consistent with hypoxic deterioration near central venules. Adherent platelets, neutrophils, and lymphocytes within sinusoids and central venules were also observed. PCR revealed that IL-2 significantly induced TNF mRNA expression in the liver. These data suggest that IL-2 activates Kupffer cells in association with the release of monokines including TNF, which causes activation of circulating leukocytes as well as hepatic sinusoidal endothelial cells. The resultant leukocyte and platelet adhesion to the endothelium may then physically impede the sinusoidal microcirculation, resulting in microscopic areas of hepatic ischemia and explaining the mechanism of IL-2-induced hepatic dysfunction.

Establishment and characterization of a human colon cancer cell line, OUMS-23, from a patient with familial adenomatous polyposis

A human colon carcinoma cell line designated OUMS-23 has been established from metastatic pericardial fluid of a male familial adenomatous polyposis patient with colon cancer. Since 1984, the epithelial cells have been maintained in culture. Ultrastructural studies revealed the presence of numerous microvilli on the cell surface and desmosomes between the adjacent cells. The cells secreted carcinoembryonic antigen into the culture medium (15 ng/10(6) cells-1 24 h-1). The cells expressed heat-stable placental-type-like alkaline phosphatase, whereas the normal counterparts expressed tissue-unspecific alkaline phosphatase. Karyotypic analysis showed that the cell line was of human origin and that the chromosome number was broadly distributed between 53 and 118. Southern blot analysis of the APC gene revealed no abnormalities in OUMS-24 cells, while Northern blot analysis demonstrated that the expression of the gene was about one-half that of the normal human fibroblasts. No mutations at the "hot spots" of codons 12 and 61 of H-, K- and N-ras proto-oncogenes were detected in the cells. The cells could grow in soft agar at a cloning efficiency of 6.5%, and upon transplantation into nude mice the cells formed tumors, which were diagnosed as differentiated adenocarcinoma.

Reduction of hepatic acute phase response after partial hepatectomy in elderly patients

The hepatic capacity for acute phase protein synthesis after partial hepatectomy in the elderly patients was prospectively studied. Forty-one patients who consecutively underwent a partial hepatectomy were grouped according to age of greater or less than 70 years; 12 were in the older group and 29 in the younger. The changes in the levels of serum interleukin-6, alpha 1-antitrypsin, alpha 1-acid glycoprotein, haptoglobin, and plasma fibrinogen were measured after surgery. The postoperative changes in standard liver function tests were also measured. The incidence of postoperative infected complications was 25% in the older group and 7% in the younger (P = 0.28). Although postoperative levels of serum interleukin-6 were similar between the two groups, those of serum alpha 1-antitrypsin, alpha 1-acid glycoprotein, and haptoglobin were significantly lower in the elderly (P < 0.05). Postoperative levels of serum alpha 1-antitrypsin and plasma fibrinogen showed an increase of about 30% compared with the preoperative values (P < 0.05) in the younger group, but no significant increase in the older. Postoperative deterioration of serum albumin levels and hepaplastin test values was also significantly more severe in the older group (P < 0.05). We conclude that in the older patients, a reduction of acute phase protein synthesis occurs after partial hepatectomy as a result of a global deterioration of liver function, and may render patients liable to infection.

Increased serum interleukin-6 level and reduction of hepatic acute-phase response after major hepatectomy

It has been proposed that a major hepatectomy impairs the liver-related host defense mechanism. The changes in the levels of serum inflammatory cytokines and plasma acute-phase proteins synthesized in the liver were measured after partial hepatectomy. Peak levels of serum interleukin-6 were significantly higher after extended lobectomy than after lobectomy or segmentectomy (p < 0.01). Serum interleukin-1 beta and tumor necrosis factor alpha levels showed no significant changes. Plasma levels of acute-phase proteins were significantly lower after lobectomy or extended lobectomy (p < 0.05). A reduced hepatic acute-phase response probably renders patients liable to infection after major hepatectomy.

Reduced hepatic functional reserve in cirrhosis and obstructive jaundice with special reference to histological morphometric analysis and galactose elimination capacity

To evaluate liver dysfunction in patients with obstructive jaundice (OJ), morphological and functional hepatic mass was analyzed in comparison with cirrhosis (LC). Total hepatic parenchymal ratio (THPR) was estimated by morphometric analysis and hepatic functional mass by galactose tolerance test (GaTT) in 30 patients who underwent hepatectomy. The value of GaTT in patients with LC was remarkably depressed compared to those with normal liver function (p < 0.001). It was also depressed in OJ (p < 0.05 vs. normal liver), but less than in LC (p < 0.05). However, THPR decreased only in LC (p < 0.05 vs. either normal liver or OJ). A significant correlation between the value of GaTT and THPR was revealed in patients with LC, but not in OJ. These results suggested that liver dysfunction in OJ was independent of the decreased number of hepatocytes, differing from LC.

Purification and characterization of angiotensin II-generating chymase from hamster cheek pouch

Hamster cheek pouch vascular tissues contain an angiotensin II-forming enzyme which is inhibited by chymostatin but not by any angiotensin-converting enzyme inhibitors. The enzyme was purified to apparent homogeneity by gel filtration and heparin-Sepharose affinity chromatography. The molecular mass estimated by sodium dodecyl sulphate polyacrylamide gel electrophoresis was 28 kDa and the optimum pH was between 7.5 and 9.0. The angiotensin II-forming activity was inhibited by chymostatin, soybean trypsin inhibitor and phenylmethylsulfonyl fluoride, but not by aprotinin. The N-terminal sequence showed high homology with chymases from various species. Thus, the angiotensin II-generating enzyme obtained from hamster cheek pouch vessels is a chymase.

Detection of cytokine mRNA-expressing cells in peripheral blood of patients with IgA nephropathy using non-radioactive in situ hybridization

IgA nephropathy (IgA-N) is considered to be an immune-mediated disorder and several immunological abnormalities have been observed. In the present study, we optimized non-radioactive in situ hybridization and applied this technique to evaluate the degree of expression of various cytokine mRNAs in peripheral blood mononuclear cells (PBMC) taken from patients with IgA-N on cytospin preparation. Using this method, together with image analysis, we examined the expression of mRNA in cells which secrete cytokines, such as IL-2, interferon-gamma (IFN-gamma), IL-4, IL-5 and IL-6. The expression of these mRNAs was clearly observed in monocytes and lymphocytes at a single-cell level. Compared with healthy adults, the expression of IL-4 mRNA, IL-5 mRNA and IL-6 mRNA, but not IL-2 mRNA or IFN-gamma mRNA, was significantly enhanced. Our results indicate that non-radioactive in situ hybridization method is a powerful technique for analysis of cytokine mRNAs in PBMC at a cellular level. Our results also suggest that mRNA expression of IL-4, IL-5 and IL-6, produced by Th2 cells, is increased in patients with IgA-N. The abnormal regulatory process involved in cytokine expression may play an important immunopathologic role in IgA-N.

Increased levels of human hepatocyte growth factor in serum and peritoneal fluid after partial hepatectomy

OBJECTIVE/METHOD

It has been reported that inflammatory cytokines up-regulate human hepatocyte growth factor synthesis in vitro. To demonstrate the relation of this growth factor to interleukin-6 and tumor necrosis factor alpha, the changes in the levels of these cytokines were measured in serum and peritoneal fluid in 22 patients after partial hepatectomy.

RESULTS

Serum and fluids levels of cytokines showed a maximum within 3 days after surgery. Cytokines concentrations were much higher in fluid than in serum (p < 0.05). The maximum serum levels of human hepatocyte growth factor were significantly correlated with those of interleukin-6, intraoperative blood loss, and operating time (p < 0.05) but not resected liver weights. In fluid level, the growth factor was also correlated with interleukin-6 (p < 0.05) but with tumor necrosis factor alpha.

CONCLUSIONS

These results suggest that human hepatocyte growth factor might be locally produced in the injured tissue associated with interleukin-6 and independently of resected liver weights.

Mapping of angiotensin II receptor subtypes in peripheral tissues of spontaneously hypertensive rats by in vitro autoradiography

1. The regulation of angiotensin II (AII) receptor subtypes was studied in peripheral tissues of 20 week old male spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats. 2. AII receptor binding was determined by a quantitative in vitro autoradiography using [125I]-[Sar1,Ile8]AII as a ligand on the kidney, adrenal gland, thoracic aorta and heart. CV-11974, a specific AT1 receptor antagonist, and CGP42112B, a specific AT2 antagonist, were used in competition with [125I]-[Sar1,Ile8]AII to differentiate AT1 and AT2 receptor binding. 3. The relative abundance of each subtype was very similar between SHR and WKY rats. In both strains of rats, the adrenal cortex contained predominantly AT1 receptors, while AT2 receptors predominated in the adrenal medulla. The kidney contained exclusively AT1 receptors over glomeruli, proximal tubules and outer medulla. AT1 receptors were predominant in the thoracic aorta and heart. 4. As for relative receptor density, important differences were observed between SHR and WKY rats. In SHR, the adrenal cortex, outer medulla of the kidney, and heart displayed higher AT1 receptor density than WKY rats. 5. These results indicate that the expression of AT1 receptors is differently regulated in some important targets of AII in SHR, and suggest that the altered regulation of AT1 receptor presented in this study should be relevant to the pathophysiological features of SHR.

Influence of light irradiation of dentine primers on dentine-resin bond

OBJECTIVE

The purpose of this study was to examine the influence of light irradiation of dentine primers that contain camphoroquinone (CQ) on the shear bond strength to dentine and their contact angle.

METHOD

Three dentine bonding systems which contain CQ, Imperva Bond, OptiBond and XR-Bond; and Light Bond, which does not contain CQ, were employed. Labial surfaces of freshly extracted lower bovine incisors were ground with no. 600 grit SiC paper. Dentine primers were applied to the dentine surfaces in two groups, irradiated and non-irradiated. A shear bond strength test was performed and the direct contact angle was measured.

RESULTS

Statistical analysis (Newman-Keuls multiple comparison P < 0.05) of the data indicated that light irradiation of the dentine primer for systems containing CQ resulted in increased bond strength and decreased contact angle.

CONCLUSION

This study indicates that for these dentine bonding systems containing CQ in their primers, light irradiation of the dentine primer is effective in improving wettability and increasing the bond strength to dentine.

Significance of aminopyrine breath test as a parameter of hepatic functional reserve in 40% partial hepatectomy of rats with CCl4-induced liver injury

Rats with CCl4-induced liver injury underwent partial (40%) hepatectomy. The [14C]aminopyrine breath test (ABT) values in rats with CCl4-induced liver injury were reduced by 34% compared with those in rats with normal liver. Preoperative ABT values clearly discriminated between survivors and those that died following 40% partial hepatectomy in rats CCl4-induced liver injury (P < 0.05). Hepatic protein synthesis was remarkably enhanced in CCl4-induced liver injury compared with normal liver (P < 0.001), and this was inversely correlated with ABT values (P < 0.001). These data show that the enhanced hepatic protein synthesis could induce a decrease of hepatic functional reserve. ABT seems to be a useful preoperative test for predicting surgical mortality following hepatectomy.

PTB domains of IRS-1 and Shc have distinct but overlapping binding specificities

PTB domains are non-Src homology 2 (SH2) phosphotyrosine binding domains originally described in the receptor tyrosine kinase substrate, Shc. By serial truncation, we show that a 174-residue region of Shc p52 (33-206) has full PTB activity. We also show that a 173-residue region of insulin receptor substrate-1 (IRS-1; residues 144-316) has related PTB activity. In vitro both domains bind directly to activated insulin receptors. Binding is abrogated by substitution of Tyr-960 and selectively inhibited by phosphopeptides containing NPXY sequences. Phosphopeptide assays developed to compare PTB domain specificities show that the Shc PTB domain binds with highest affinity to psi XN beta 1 beta 2 pY motifs derived from middle T (mT), TrkA, ErbB4, or epidermal growth factor receptors (psi = hydrophobic, beta = beta-turn forming); the IRS-1 PTB domain does not bind with this motif. In contrast, both the Shc and IRS-1 PTB domains bind psi psi psi XXN beta 1 beta 2pY sequences derived from insulin and interleukin 4 receptors, although specificities vary in detail. Shc and IRS-1 are phosphorylated by distinct but overlapping sets of receptor-linked tyrosine kinases. These differences may be accounted for by the inherent specificities of their respective PTB domains.

MR of childhood-onset dentatorubral-pallidoluysian atrophy

MR findings in a 14-year-old boy with progressive myoclonic epilepsy, who was diagnosed as having dentatorubral-pallidoluysian atrophy by DNA analysis, were compared with those of his father, who had adult-onset dentatorubral-pallidoluysian atrophy. Besides showing severe brain atrophy, especially of the brain stem tegmentum and cerebellum, MR showed diffuse periventricular hyperintensity on T2-weighted images. As compared with the proband, the father had a mild case.

Distributions of nitropyrenes and mutagenicity in airborne particulates collected with an Andersen sampler

Distributions of 1,3-dinitropyrene (1,3-DNP), 1,6-DNP, 1,8-DNP, 1-nitropyrene (1-NP) and mutagenicity in airborne particulates collected in downtown Kanazawa, Japan with an Andersen high-volume air sampler were examined. Mutagenicities of benzene-ethanol extract from particulates were determined by the Ames test using S. typhimurium strains without S9 mix, while concentrations of DNPs and 1-NP were determined by high-performance liquid chromatography (HPLC) using chemiluminescence detection. In the finest particulate fraction (smaller than 1.1 microns), 68% and 75% of the total mutagenicities were observed in TA98 and YG1024 strains, respectively. In the same fraction, 65-82% of three DNPs as well as 84% of 1-NP were observed. Mutagenic contributions of 1,3-DNP, 1,6-DNP, 1,8-DNP and 1-NP in the extract were respectively 0.6, 1.2, 1.8 and 1.6% in the TA98 strain, and 2.5, 5, 9 and 2.1% in the YG1024 strain.

In situ hybridization of interleukin 6 in diabetic nephropathy

Increased mesangial expansion is one of the most characteristic histological changes in diabetic nephropathy (DN). Although the pathogenesis of DN remains unclear, recent studies associate interleukin (IL) 6 with mesangial proliferative glomerulonephritis. To elucidate the expression and localization of IL-6 mRNA in renal tissues of patients with DN, a high-resolution in situ hybridization using digoxigenin-labeled oligonucleotide was performed. Patients were divided into three groups based on light microscopy findings: mild (group 1), moderate (group 2), and severe (group 3) mesangial expansion. The relationship between the expression of IL-6 mRNA and the degree of glomerular mesangial expansion in DN was examined. Individual cells positive for IL-6 mRNA were observed in glomeruli. These cells were mesangial cells, glomerular epithelial cells, and Bowman's capsule. The signal intensity was strongest in tissues from group 2 but was weak in those from groups 1 and 3. Most cells in the area of mesangial proliferation were strongly stained for IL-6 mRNA, and few positive cells were found in the Kimmelstiel-Wilson nodular lesion. In the interstitium, some tubules, particularly atrophic tubules, and some infiltrating cells were positively stained for IL-6 mRNA. The interstitial expression of IL-6 mRNA correlated significantly with the degree of interstitial injury and was remarkable in tissues from groups 2 and 3. We conclude that IL-6 mRNA is expressed by glomerular resident cells and interstitial cells in the renal tissue of patients with DN and that its expression may be associated with mesangial proliferation and may be involved in the tissue injury of DN.

Influence of light intensity on shear bond strength to dentin

PURPOSE

To investigate the influence of light intensity on dentin bond strength of five dentin bonding systems.

MATERIAL AND METHODS

The light intensity used to polymerize specimens was controlled at the levels of 100, 200, 400, 600, 800, and 1000 W/m2 (470 +/- 40 nm). Labial surfaces of freshly extracted lower bovine incisors were ground with #600 grit SiC paper to expose dentin. After primer application, bonding agents were applied and bonded with resin composites. A shear bond strength test was performed and the data were analyzed by a one-way ANOVA followed by Newman-Keuls multiple comparison (P<0.05).

RESULTS

Statistical analysis of the data indicated that light intensity affected the bond strength to dentin. The mean bond strength of all bonding systems decreased with lower light intensity. The tendency of decreasing bond strength was different among the test materials and each test material had a threshold light intensity that resulted in statistically the same bond strength obtained using a light intensity of 1000 W/m2.

Vascular affinity of trandolapril

This article discusses the pharmacologic basis on which trandolapril exhibits a more potent and longer-lasting antihypertensive effect than its chemical prototype enalapril. Our studies have shown that 1) trandolapril and its active metabolite trandolaprilat are more lipophilic than enalapril and its active diacid enalaprilat; 2) trandolaprilat is three times more potent than enalaprilat in vitro; and 3) trandolapril is 10 times more effective and longer-acting than enalapril in lowering the blood pressure of spontaneously hypertensive rats. The long duration of action of trandolapril can be attributed to its long-lasting inhibition of the vascular tissue angiotensin converting enzyme (ACE). The long action onto the vascular tissue ACE may be due to the high lipophilicity of trandolapril which may increase its tissue penetration and its elimination half-life from the tissue, and the unique nature of the vascular tissue which, unlike the other tissues, does not respond to trandolapril with the induction of de novo ACE that may counteract the ACE inhibition. These data imply that trandolapril is a potent ACE inhibitor with distinctively long action, which might be a result of its vascular tissue affinity and the lack of any ACE inducing ability of the vascular tissue.

Reduced N-acetylaspartate in the brain observed on in vivo proton magnetic resonance spectroscopy in patients with mental retardation

Volume-selective proton magnetic resonance spectroscopy (1H-MRS) of the brain was performed with a 1.5T magnet in 28 patients with unclassified mental retardation (MR) and in 25 age-matched healthy children. Peaks of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr), but not of lactate, were observed in both groups on 1H-MRS. In all our subjects of this age range, 1H-MRS revealed an increase with advancing age in the ratio of NAA/Cho (P = .0031), but no developmental change in the NAA/Cr and Cho/Cr ratios. The NAA/Cho ratio was lower in patients with MR than in controls (P = .0016). The NAA/Cr ratio tended to be lower in the MR group, and the Cho/Cr ratio did not differ between patients with MR and controls. These results suggest that in patients with MR, NAA decreases and a disorder and/or dysfunction of neurons in the brain exists.

The effect of fatigue caused by electrical induction or voluntary contraction on Ia inhibition in human soleus muscle

A comparison of the effect of fatigue caused by electrical induction or voluntary contraction on Ia inhibition in human soleus muscle was investigated in fourteen healthy male subjects. The Hoffmann reflex (H reflex) was employed to elucidate the contribution of fatigue induced contraction to the Ia inhibition. A statistically significant difference (P < 0.05) in H reflex amplitude between the intermittent stimulation at 15 Hz and voluntary contraction was observed. Our study suggested that Ia inhibition in human soleus muscle, caused by electrically induced or voluntary contraction, induced differences in the number of impulses in the group Ia fibers, between the two conditions.