Potent antihypertrophic effect of the bradykinin B2 receptor system on the renal vasculature

BACKGROUND

Angiotensin type 1 (AT1) receptor-deficient mice (Agtr1-/-), which selectively lack both AT1A and AT1B receptor genes, are characterized by marked intrarenal vascular thickening. In the present study, we explored the possible involvement of the kinin-kallikrein system in the development of this renal vascular hypertrophy.

METHODS

Wild-type and Agtr1-/- mice were examined for the developmental regulation pattern of the kinin-kallikrein system and treated with aprotinin (a kallikrein inhibitor), AcLys [D-b Nal7, Ile8] des-Arg9-bradykinin (a bradykinin B1 receptor antagonist), or Hoe-140 (a bradykinin B2 receptor antagonist) from 3 to 14 days of age.

RESULTS

The normal postnatal up-regulation of kininase II was organ-specifically suppressed in Agtr1-/- kidneys at 2 and 3 weeks of age. Immunohistochemical staining in Agtr1-/- mice revealed tissue kallikrein staining along the nephron from connecting tubules to cortical collecting tubules in proximity to the hypertrophic vasculature, whereas tissue kallikrein staining was confined to connecting tubules in wild-type mice. Aprotinin and Hoe-140 accelerated the vascular hypertrophy significantly as determined by wall thickness ratio, whereas B1 receptor antagonism had no effect.

CONCLUSION

The kinin-kallikrein system in the Agtr1-/- mouse kidney is functionally activated by local suppression of kininase II and extensive redistribution of kallikrein to perivascular areas. This activation, specific to the kidney, serves to dampen a development of the marked vascular hypertrophy. These results demonstrate, to our knowledge for the first time, the antihypertrophic effect of the bradykinin B2 receptor system on the renal vasculature in vivo.

[A case of congenital skull defect complicated with arachnoid cyst]

A 3-month-old boy was referred to our hospital with left temporal bone defect and bulging skin. The skull defect had been recognized since birth. There was no family history of any congenital anomaly and his physical development was normal for his age. His bulged left temporal region was covered by normal skin and a skull defect measuring 2 x 2 cm in size was palpated at the center. CT scan revealed skull defect at the pterion accompanied with widening of the middle cranial fossa. Arachnoid cyst of the middle cranial fossa was also suspected. The skull defect gradually enlarged and especially on crying the left temporal skin bulging became more marked. The bone edge of the defect was thin and was deflected outward. The operation was planned and performed at the age of 11 months. After excision and fenestration of the arachnoid cyst, duraplasty and cranioplasty were performed using split-thickness calvarial bone graft. Splitting the frontal calvarial bone suitable for the defect, the outer table was returned to the donor site, and the inner table was fixed into the defect. Follow-up CT one year after surgery revealed a satisfactory cosmetic result and no bone resorption. Split calvarium cranioplasty is considered to be even more useful in an infant.

A 1-hour enzyme-linked immunosorbent assay for quantitation of acrolein- and hydroxynonenal-modified proteins by epitope-bound casein matrix method

A simple and rapid enzyme-linked immunosorbent assay (ELISA) method for quantitation of acrolein and 4-hydroxy-2-nonenal (HNE)-modified proteins was developed. Microtiter plate wells were precoated and blocked simultaneously with epitope-bound bovine caseins as matrix proteins, and aldehyde-modified proteins were quantitated by a competition assay with a monoclonal antibody specific for acrolein-modified lysine or HNE-modified histidine epitopes. Minimal reaction times required for the coating/blocking; first monoclonal antibody and the peroxidase-conjugated second antibody binding steps were 3, 3, and 7 min, respectively, the former two steps being found to be or akin to diffusion-rate-limiting reactions. The convenient ELISA should find an application for analyses of the intricate processes involved in oxidative stress and carcinogenic insult. The epitope-attachment methodology may also be advantageous for the quantitation of various other biologically important haptenic molecules.

The renal lesions that develop in neonatal mice during angiotensin inhibition mimic obstructive nephropathy

BACKGROUND

Inhibition of angiotensin action, pharmacologically or genetically, during the neonatal period leads to renal anomalies involving hypoplastic papilla and dilated calyx. Recently, we documented that angiotensinogen (Agt -/-) or angiotensin type 1 receptor nullizygotes (Agtr1 -/-) do not develop renal pelvis nor ureteral peristaltic movement, both of which are essential for isolating the kidney from the high downstream ureteral pressure. We therefore examined whether these renal anomalies could be characterized as "obstructive" nephropathy.

METHODS

Agtr1 -/- neonatal mice were compared with wild-type neonates, the latter subjected to surgical complete unilateral ureteral ligation (UUO), by analyzing morphometrical, immunohistochemical, and molecular indices. Agtr1 -/- mice were also subjected to a complete UUO and were compared with wild-type UUO mice by quantitative analysis. To assess the function of the urinary tract, baseline pelvic and ureteral pressures were measured.

RESULTS

The structural anomalies were qualitatively indistinguishable between the Agtr1 -/- without surgical obstruction versus the wild type with complete UUO. Thus, in both kidneys, the calyx was enlarged, whereas the papilla was atrophic; tubulointerstitial cells underwent proliferation and also apoptosis. Both were also characterized by interstitial macrophage infiltration and fibrosis, and within the local lesion, transforming growth factor-beta 1, platelet-derived growth factor-A and insulin-like growth factor-1 were up-regulated, whereas epidermal growth factor was down-regulated. Moreover, quantitative differences that exist between mutant kidneys without surgical obstruction and wild-type kidneys with surgical UUO were abolished when both underwent the same complete surgical UUO. The hydraulic baseline pressure was always lower in the pelvis than that in the ureter in the wild type, whereas this pressure gradient was reversed in the mutant.

CONCLUSION

The abnormal kidney structure that develops in neonates during angiotensin inhibition is attributed largely to "functional obstruction" of the urinary tract caused by the defective development of peristaltic machinery.

Vascular response to angiotensin II is exaggerated through an upregulation of AT1 receptor in AT2 knockout mice

Blood pressure is elevated and pressor response to angiotensin II (Ang II) is exaggerated in AT2 null mice. The purpose of the present study was to elucidate the mechanism for the increased responsiveness to Ang II in the mice. The contraction of aortic strips generated by Ang II was significantly greater in the AT2 gene-deleted mice than the control, which was completely abolished by AT1 antagonist losartan. The aortic content of AT1 receptor was significantly increased (P < 0.05, n = 5) in the AT2 null mice (212 +/- 58.2 fmol/mg protein) compared with the control (98.2 +/- 55.9 fmol/mg protein). While both AT1 and AT2 mRNAs were expressed in the aorta of the control mice, only AT1 mRNA was expressed in the AT2 knockout mice. The expression of AT1 mRNA in the AT2 knockout mice was significantly higher (1.5-fold, P < 0.05, n = 5) than that in the control. The present study clearly demonstrated that the increased vascular reactivity to Ang II in AT2 knockout mice is at least partly due to an increased vascular AT1 receptor expression and suggested that AT2 counteracts AT1-mediated vascular action of Ang II through downregulation of AT1 receptor by a crosstalk between these receptors by some as yet unknown mechanisms.

Decreased expression of the peroxisomal bifunctional enzyme and carbonyl reductase in human hepatocellular carcinomas

Human hepatocellular carcinomas (HCC) are known to frequently exhibit clear-cell or fatty change. The expression of three enzymes related to fatty acid metabolism, the peroxisomal bifunctional enzyme (enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase, BE), cytosolic carbonyl reductase (CR) and the alpha-class glutathione S-transferase (GST) was investigated immunohistochemically in 45 HCC samples, to examine their relevance to this phenomenon and to antioxidant cellular defence. The tumour sizes ranged from 3 mm to 37 mm in diameter (mean 19 mm). Of 8 highly differentiated carcinomas (Edmondson's grade 1), 5 and 6 showed positive staining for BE and CR respectively, like the surrounding non-hepatoma tissues. Of 37 Edmondson's grade II-IV lesions, 31 exhibited negative or only weakly positive staining for both enzymes, as compared with the surrounding tissues. The combined rates for weakly positive and negative staining for BE or CR were proportional to the degree of dedifferentiation. However, 3 of 26 grade III tumours showed enhanced staining. Intensities of staining for CR were in accordance with those for BE in 40 of the total of 45 HCC. Immunoblot analysis also demonstrated concerted alteration of the two enzymes in carcinoma tissues. The staining of the alpha-class GST was hardly changed in Edmondson's grade I and II cases but was decreased in 24 of 31 grade III and IV lesions. The great majority of the BE-negative carcinomas did not demonstrate fatty or clear-cell change. These results suggested that BE and CR might be possible markers for the analysis of multistage hepatocarcinogenesis but that decrease or loss was not reflected in increased fat storage.

Prominent medial hypertrophy of renal arterioles in an infant with hyporeninemic hypoaldosteronism

We describe an 11-month-old boy who presented clinically with hyperkalemic renal tubular acidosis due to hyporeninemic hypoaldosteronism. Persistent hyperchloremic acidosis and mild azotemia were present. All abnormal laboratory values were corrected by the administration of fludrocortisone. Renal biopsy showed prominent medial hypertrophy of renal arterioles and interstitial fibrosis, which closely resemble those of the gene-targeted mice with disruption of the renin angiotensin system. This is the first case report raising the possibility that a defective renin angiotensin system in infancy may lead to tubulointerstitial damage with medial hypertrophy of intrarenal arterioles.

Quantitative differences in the active-site hydrophobicity of five human glutathione S-transferase isoenzymes: water-soluble carcinogen-selective properties of the neoplastic GSTP1-1 species

The active-site (the H-site) hydrophobicity of five human glutathione S-transferases (GSTs) was analyzed by application of linear free energy relationships (LFERs) with a series of S-alkylated glutathione inhibitors, GS(CH2)n - 1CH3 (n = 1-14). Distinct linear reltionships were observed in the plots of log Ki (inhibition constant) vs n for the five forms, whereby the Kis varied by three to four orders of magnitude. Mean free enthalpy changes per methylene group (-Delta DeltaG degreess), a measure of H-site hydrophobicity, were in the order M1-1 (4.6 kJ/mol) > A1-1 (3. 9 kJ/mol) > A1-2 (3.8 kJ/mol) > A2-2 (2.8 kJ/mol) > P1-1 (1.6 kJ/mol). The quantitative differences may in part account for the extraordinary broad and overlapping substrate specificities of the Alpha-, Mu-, and Pi-class isoenzymes. In contrast to the Alpha and Mu classes being selective for strongly electrophilic compounds, the neoplastic P1-1 species was indicated to be selective for weakly electrophilic and water-soluble carcinogens such as acrolein and hydroxyalkenals.

Rare case of small-cell carcinoma arising from the endometrium with paraneoplastic retinopathy

We present the fourth known case of endometrial carcinoma, and the second case of endometrial small-cell carcinoma, to be associated with paraneoplastic retinopathy. Initial symptoms were decreased visual acuity and a narrowing of the visual field. Endometrial carcinoma was diagnosed several months later. An antibody to 34-kDa bovine retinal antigen was detected in the patient's serum. Thus, autoimmunity was suspected as the cause of the retinopathy. In patients with endometrial carcinoma with visual disturbance of unknown cause, paraneoplastic retinopathy should be suspected.

Altered glutathione transferase levels in rat skin inflamed due to contact hypersensitivity: induction of the alpha-class subunit 1

Since glutathione transferases (GSTs) are suggested to be involved in the prevention of tissue damage by oxidative stress, quantitative and qualitative alterations of GST forms were examined in rat skin after induction of inflammation by 0.6 and 1% 1-chloro-2, 4-dinitrobenzene (CDNB) treatment. With 0.6% CDNB, the GST activity in supernatant preparations was 1.8-fold higher than that for control skin, with most GSTs in both cases being bound to S-hexyl-GSH-Sepharose. Major GST subunits of control skin were identified as subunits 7, 4 and 2 by HPLC and chromatofocusing at pH11-7. These subunits were increased in inflamed skin by 0.6% CDNB and, in addition, the subunit 1 of the Alpha class and subunit 6, both hardly detectable in control skin, were expressed. The specific activity value for GST 7-7 from the inflamed skin by 0.6% CDNB was 2. 4-fold lower than that from control skin. However, in the case of inflamed skin after application of 1% CDNB, GST activity was decreased to 69% of the control value and most activity was recovered in fractions binding to a GSH-Sepharose but not a S-hexyl-GSH-Sepharose column. GSTs eluted from the former column demonstrated a restored capacity to bind to the latter, suggesting the GSTs in inflamed skin to be partly inactivated and that they regained activity on exposure to GSH. The Km and Vmax values for GSH of GST 4-4 from inflamed skin after 1% CDNB treatment were 6-fold and 2-fold higher, respectively, than those for the enzyme from control skin, suggesting partial enzyme modification. These results suggest that not only quantitative but also qualitative alterations of GST subunits occur with CDNB-induced inflammation in vivo.

Angiotensin induces the urinary peristaltic machinery during the perinatal period

The embryonic development of mammalian kidneys is completed during the perinatal period with a dramatic increase in urine production, as the burden of eliminating nitrogenous metabolic waste shifts from the placenta to the kidney. This urine is normally removed by peristaltic contraction of the renal pelvis, a smooth muscle structure unique to placental mammals. Mutant mice completely lacking angiotensin type 1 receptor genes do not develop a renal pelvis, resulting in the buildup of urine and progressive kidney damage. In mutants the ureteral smooth muscle layer is hypoplastic and lacks peristaltic movements. We show that angiotensin can induce the ureteral smooth muscles in organ cultures of wild-type, but not mutant, ureteral tissues and that, in wild-type mice, expression of both renal angiotensin and the receptor are transiently upregulated at the renal outlet at birth. These results reveal a new role for angiotensin in the unique cellular adaptations of the mammalian kidney to the physiological stresses of postnatal life.

Inhibition of nuclear envelope reconstitution in Xenopus interphase egg extract by hemin

Addition of hemin to the nuclear reconstitution system of Xenopus interphase egg extract using sperm head chromatin resulted in abnormal pseudonuclei exhibiting flattened membrane patches randomly distributed both on the surface and inside the nuclei. The structures that resembled nuclear pores were observed on these flattened membrane patch structures. Although the nucleosome structure was formed as revealed by the micrococcal nuclease digestion, the B-type lamin uptake into the nuclei was inhibited by hemin. Using heminagarose affinity chromatography, we isolated several hemin-binding proteins from fully reconstituted pseudonuclei. Some of the hemin-binding proteins bound concanavalin A (Con A). Comparison of hemin-binding proteins with those isolated from both fractions of supernatant and pellet separated by high speed centrifugation of the egg extract showed that the hemin-binding proteins of pseudonuclei were supplied from both fractions. The uptake of nuclear hemin-binding proteins did not occur in the incompletely reconstituted nuclei resulting from addition of excess sperm chromatin to the system. These results suggest that the hemin-binding proteins participate in the late steps of nuclear reconstitution during formation of the nuclear envelope.

Role of angiotensin in the congenital anomalies of the kidney and urinary tract in the mouse and the human

The role of angiotensin in fluid and electrolyte and blood pressure homeostasis is well known. Recent developments indicate that angiotensin has a profound role not only in the developing urinary tract but also in the response of the urinary tract to specific noxious stimuli. Furthermore, the role of angiotensin II and its receptor has been understood quite poorly with respect to the developing renal unit. Knockout mice for the ATR2 gene show a significant incidence of congenital urinary tract anomalies. The congenital anomalies of the kidney and urinary tract (CAKUT) seen in these mice are very similar to the anomalies observed in humans. This has been supported further by the finding of an abnormality in the genetic sequence in patients with CAKUT. This article reviews experimental laboratory data as well as the potential implications for humans.

Identification of glutathione S-transferase p-1 as the class pi form dominantly expressed in mouse hepatic adenomas

To clarify which of the two genes for pi class glutathione S-transferases (GSTs) (p-1 and p-2) is dominantly expressed in mouse hepatic adenomas, the relative mRNA levels were examined by means of the reverse transcription-polymerase chain reaction (RT-PCR). Hepatic adenomas were induced in male and female B6C3F1 mice by diethylnitrosamine treatment. Northern blot analysis revealed that pi class mRNA levels were decreased in adenomas of male mice, but increased in those of females, with reference to the respective surrounding non-adenoma tissues. In contrast to the marked sex difference in surrounding tissues, pi class GST mRNA levels in adenomas were almost the same in both males and females. To evaluate p-1 and p-2 mRNA levels separately, the products of RT-PCR employing primers common for both cDNAs were digested with the endonuclease BanI (specific for p-2) and then resolved by electrophoresis. The p-1 mRNA was thus found to be dominant in adenomas of both female and male mice. The p-2 mRNA levels were increased in the lesions as compared with those in the surrounding non-adenoma tissues. Recombinant p-1 and p-2 proteins were expressed in Escherichia coli. Unlike p-1, the p-2 protein did not show any significant activity towards 1-chloro-2,4-dinitrobenzene and did not bind to S-hexylglutathione-Sepharose despite immunological cross-reactivity. The dominant pi class form in adenomas could also be identified as p-1 by its binding to S-hexylglutathione-Sepharose. Single radial immunodiffusion analyses confirmed that the p-1 protein levels were in line with the mRNA findings, i.e., 1.9+/-0.3 mg/g adenoma as compared to 6.5+/-1.2 mg/g non-adenoma tissue for males and 2.2+/-0.6 mg/g as compared to 0.7+/-0.2 mg/g for females. The results thus indicated that the change of pi class forms in adenomas is caused mainly by alteration in the p-1 level and the contribution of p-2 is minimal.

Murine double nullizygotes of the angiotensin type 1A and 1B receptor genes duplicate severe abnormal phenotypes of angiotensinogen nullizygotes

Rodents are the unique species carrying duplicated angiotensin (Ang) type 1 (AT1) receptor genes, Agtr1a and Agtr1b. After separately generating Agtr1a and Agtr1b null mutant mice by gene targeting, we produced double mutant mice homozygous for both Agtr1a and Agtr1b null mutation (Agtr1a-/-; Agtr1b-/-) by mating the single gene mutants. Agtr1a-/-, Agtr1b-/- mice are characterized by normal in utero survival but decreased ex utero survival rate. After birth they are characterized by low body weight gain, marked hypotension, and abnormal kidney morphology including delayed maturity in glomerular growth, hypoplastic papilla, and renal arterial hypertrophy. These abnormal phenotypes are quantitatively similar to those found in mutant mice homozygous for the angiotensinogen gene (Agt-/-), indicating that major biological functions of endogenous Ang elucidated by the abnormal phenotypes of Agt-/- are mediated by the AT1 receptors. Infusion of Ang II, AT1 blockers, or an AT2 blocker was without effect on blood pressure in Agtr1a-/-; Agtr1b-/- mice, indicating that AT2 receptor does not exert acute depressor effects in these mice lacking AT1 receptors. Also, unlike Agt-/- mice, some Agtr1a-/-; Agtr1b-/- mice have a large ventricular septum defect, suggesting that another receptor such as AT2 is functionally activated in Agtr1a-/-, Agtr1b-/- mice.

Phenotypic alterations of small cell lung carcinoma induced by different levels of wild-type p53 expression

p53 induces both growth arrest and apoptosis in cancer cells. To clarify whether the level of p53 expression determines the response of small cell lung carcinoma (SCLC) cells, we assessed the effect of various p53 levels on a p53-null SCLC cell line, N417, using a tetracycline (Tc)-regulated inducible p53 expression system. Apoptosis was induced in SCLC cells with high p53 expression. Although low levels of p53 induced G1 arrest accompanied by p21 expression, cells with G1 arrest seemed to undergo apoptosis after further cultivation. Expression of exogenous p21 induced G1 arrest but not apoptosis in SCLC cells, suggesting that p53-mediated G1 arrest was induced through p21 expression. Moreover, high level of p53 expression down-regulated Bcl-2 expression in SCLC cells, while Bax was consistently expressed irrespective to the level of p53 expression. These results suggest that p53-mediated apoptosis and G1 arrest depend on level of p53 expression in SCLC cells and that the relative dominancy of Bax to Bcl-2 is involved in the induction of apoptosis by high level of p53 expression.

Podocyte detachment and epithelial cell reaction in focal segmental glomerulosclerosis with cellular variants

In primary focal segmental glomerulosclerosis with cellular variants the type of epithelial cells that segmentally or globally increased and their relation to sites where podocytes detached from the capillary wall, remain unclear. Two renal samples containing glomeruli with cellular variants were serially examined using transmission electron microscopy. A total of 10 lesions, including 2 collapsing glomerulopathy, 7 cellular lesions, and 1 sclerosis, were examined. Disappearance of the dense basal band of microfilaments from portions of podocytes was followed by detachment from the capillary basement membrane, resulting in segmental denudation of the capillary wall. The defects were not covered by other portions of epithelial cells, when the defects occurred in more central regions of the glomerulus. When detachment of podocytes occurred in the peripheral areas of the glomerulus, the defects were covered with new basement membrane and by other epithelial cells. These epithelial cells were characterized by the formation of intercellular junctional complexes of zonula adherens and desmosomes between each other and with the parietal epithelial cells (PECs), by showing occasional cilia, apoptotic nuclei, and mitosis. Thus, repair is achieved as the defect is covered by the participation of PECs; synechia and glomerular sclerosis result, depending upon the extent of the original podocyte injury.

[Usefulness of glutathione S-transferase as a tumor marker]

The glutathione S-transferases (GSTs), a family of multifunctional proteins, catalyze the glutathione conjugation reaction with electrophilic compounds biotransformed from xenobiotics, including carcinogens, and are grouped into four classes, Alpha, Mu, Pi and Theta. Some of these forms are suggested to act to prevent carcinogenesis by detoxifying proximate or ultimate carcinogens. In neoplastic cells, specific forms are known to be expressed and have been known to participate in their resistance to anticancer drugs. In this article, we review recent findings regarding the respective molecular forms involved in carcinogenesis and their usefulness as tumor markers. GST M1 and GST T1 genes are polymorphic in the population and losses of these genes have been suggested as possible markers for greater susceptibility to lung cancer among smokers and several other cancers. Since many GST inducers prevent rodent chemical carcinogenesis, potential chemopreventive agents have been screened by their induction capabilities. However, reliable markers useful to predict results of prospective chemopreventive trials in populations are not established. Immunohistochemical studies have revealed that many cancers, histologically classified as adenocarcinomas or squamous cell carcinomas, express GST P1-1. Its expression is regulated at transcriptional level and regulatory elements of the gene have been clarified. However, transacting factors responsible for expression in cancer tissues remain to be clarified. In addition, stability of GST P1 mRNA is suggested to be partly responsible in some cell lines. Plasma or serum GST P1-1 levels are increased in 30-50% of patients with cancers of the gastrointestinal tract. This form is also suggested to participate in resistance to anticancer drugs such as cisplatin and daunorubicin, and its expression in cancer tissues may be of prognostic value in cancer patients. Further studies on this enzyme family are clearly needed to obtain a better understanding of cancer prevention and therapy.

Release of superoxide anion from polymorphonuclear leukocytes stimulated by rubella viral antigen-antibody complex in vitro

Using a highly sensitive and specific chemiluminescence (CL) method, we detected the release of superoxide anion (O2-.) from human polymorphonuclear leukocytes (PMNLs) stimulated by rubella viral antigen-antibody complex (VAAC) adsorbed on latex particles. The amount of superoxide anion produced by PMNLs was proportional to the amount of VAAC. Neither rubella virus alone nor antibody alone, adsorbed on latex particles, stimulated production of superoxide anion by PMNLs. It is likely that rubella virus requires the presence of antibody in order to be recognized by PMNLs, and that the superoxide anion is somehow involved in the disease process of rubella.

Characterization of S-hexylglutathione-binding proteins of human hepatocellular carcinoma: separation of enoyl-CoA isomerase from an Alpha class glutathione transferase form

Recent studies have revealed binding of mitochondrial enoyl-CoA isomerase (ECI) to S-hexylglutathione-Sepharose, an affinity matrix used for purification of glutathione transferases (GSTs), and the enzyme has been suggested to be identical with the Alpha class form of GST with a subunit molecular mass of about 30 kDa. In the present study, S-hexylglutathione-binding proteins of human hepatocellular carcinomas were characterized to examine their identity. Supernatant fractions of carcinoma and surrounding tissues were applied to an affinity column, and bound fractions were resolved into three proteins with subunit molecular masses/pI values of 33 kDa/7.0, 30 kDa/5.8 and 29 kDa/5.8 in addition to the well-characterized four GST subunits, A1, A2, M1 and P1, by two-dimensional gel electrophoresis. The proteins were further purified by chromatofocusing at pH 7.4-4.0. The 30 and 29 kDa proteins were eluted at pH 4.9 and by 1 M NaCl respectively, and could be clearly separated from each other. The 29 kDa protein exhibited a low but significant activity towards 1-chloro-2,4-dinitrobenzene (4.25 micromol/min per mg of protein) and reacted with anti-(GST A1-2) antibody, suggesting that it is a member of the GST Alpha class. The 30 kDa protein did not react with anti-GST antibodies and was identified as ECI by immunoblotting and N-terminal-amino-acid-sequencing analyses. The results thus indicated that the Alpha class GST form composed of the 29 kDa subunits and ECI are two different proteins. The 33 kDa protein was eluted from the chromatofocusing column at pH 7.0 and did not react with either anti-GST antibodies or antibodies against mitochondrial enzymes involved in the beta-oxidation of fatty acids. However, it exhibited a carbonyl reductase activity with menadione and ubiquinone, and amino acid sequences of its peptides cleaved by Staphylococcus aureus V8 proteinase were consistent with those reported for the enzyme. Thus this protein binding to S-hexylglutathione-Sepharose was identified as carbonyl reductase.

AvaI polymorphism in the human transferrin gene

A guanine-adenine substitution was observed in exon 5 of the human transferrin (TF) gene. The nucleotide change led to an AvaI digestion site. Analysis of the segregation of the AvaI polymorphism and serum TF phenotypes indicated that an intragenic recombination occurred between the AvaI polymorphic site and the mutation site in the TF gene which determines the two common TF alleles, TF*C1 and TF*C2.

Decrease in class pi glutathione transferase mRNA levels by ultraviolet irradiation of cultured rat keratinocytes

The effect of ultraviolet (UV) B irradiation on pi class glutathione transferase (GST-P) gene expression was examined in cultured rat keratinocytes. Immunoblotting demonstrated GST-P to be the major GST form in the cells, and it was significantly decreased following irradiation. Northern blot analysis revealed that the mRNA decreased to 10-25% of the initial value 24 h after irradiation at a dose of 40 mJ/cm2. No remarkable changes were observed at earlier time points. Hydrogen peroxide treatment enhanced GST-P mRNA expression, with a 70% increase at 250 microM concentration. Alterations in possible trans-acting factors were examined to clarify the mechanism of repression by UV irradiation. c-Jun mRNA was induced 3.5-fold at 4 h after irradiation, but by 24 h fell to a lower level than that observed initially. c-Fos mRNA was increased 10-fold at 1 h but was completely suppressed at 12 and 24 h. Thus, the changes of c-Jun and c-Fos mRNA differed from that of GST-P mRNA. The level of mRNA for silencer factor-B was decreased to less than 10% at 12 h. UV irradiation of cells transfected with the chloramphenicol acetyltransferase (CAT) reporter gene containing enhancer (GPE I) or silencer regions of the GST-P gene did not suppress CAT activity. Although basal expression of the GST-P gene was mainly dependent on GPE I, altered expression of c-jun, c-fos and other genes coding for factors possibly trans-acting on GPE I did not appear to be responsible for the decreased GST-P mRNA levels.

Relationship between the CYP2D6 genotype and the steady-state plasma concentrations of trazodone and its active metabolite m-chlorophenylpiperazine

The relationship between the cytochrome P450 (CYP) 2D6 genotype and the steady-state plasma concentrations (Css) of trazodone and its active metabolite m-chlorophenylpiperazine (mCPP) was studied in 54 depressed Japanese patients receiving trazodone 150 mg at bedtime. By use of allele-specific PCR analysis, the wild type allele, three mutated alleles causing absent enzyme activity (CYP2D6A, CYP2D6B and CYP2D6D) and one mutated allele causing decreased enzyme activity (CYPZD6 Ch) were identified. The means (ranges) of the Css of trazodone, corrected to the median body weight in 17 cases with no mutated allele, 27 cases with one mutated allele and 10 cases with two mutated alleles, were 556 (281-1115), 643 (302-1362) and 671 (234-1418) ng/ml, respectively, while the values of mCPP were 60 (35-121), 65 (33-99) and 58 (38-112) ng/ml, respectively. Neither the Css of trazodone (F = 0.80, P = 0.45) nor that of mCPP (F = 0.49, P = 0.61) significantly differed among the three groups. The present study thus suggests that the CYP2D6 genotype cannot predict the Css of these compounds.

Intermittent trimethoprim-sulfamethoxazole in children with vesicoureteral reflux

The effectiveness of intermittent low-dose trimethoprim-sulfamethoxazole (TMP-SMZ) for the prophylaxis of recurrent urinary infection is well established in adults. The present study assessed the effectiveness and safety of intermittent low-dose TMP-SMZ in 35 children (24 boys, 11 girls, aged 1 month to 9 years, median age 5 months) with vesicoureteral reflux; 18 children had bilateral reflux. A total of 53 refluxing ureters were graded as I in 2, II in 16, III in 19, IV in 14, and V in 2 cases. The children were given 1 mg/kg body weight of trimethoprim together with 5 mg/kg of sulfamethoxazole at bedtime every other day for 6-50 months (mean +/- SD, 22.9 +/- 11.7 months). None of the boys had a recurrence of urinary infection, while 2 of the 11 girls had a total of 7 recurrences during the prophylaxis period, with a recurrence rate of 0.027 per patient month in girls. Both girls were over 3 years and had a mildly unstable bladder. Transient neutropenia (< 1,000/microliter) developed in 2 infants during the prophylaxis period, but disappeared spontaneously. Intermittent low-dose TMP-SMZ seemed very effective for the prevention of recurrent urinary infection in children with ureteral reflux even of higher grades.