Blood pressure control in Japanese hypertensives with or without type 2 diabetes mellitus

Patients with type 2 diabetes mellitus and hypertension are thought to be at high risk for cardiovascular diseases. Recent guidelines for treatment of hypertension such as the JNC VI and WHO/ISH guidelines, recommend that antihypertensive agents be strated at as low as at 130/85 mmHg and that blood pressure be lowered to less than 130/85 mmHg. Our study was designed to clarify how well and to what extent blood pressure (BP) was controlled in Japanese hypertensive patients with or without type 2 diabetes mellitus. We interviewed two hundred physicians, randomly sellected from among the members of the Japanese Society of Hypertension (JSH) (n=98) and the Japanese Diabetes Society (JDS) (n=102) and obtained information regarding five most recent cases of hypertension with (n=954 in total) and their 2 most recent cases of hypertension without diabetes (n=371 in total). The achieved BP was below 140/90 mmHg in 40.5% of non-diabetic and 38.3% of diabetic hypertensives. The percentage of patients whose BP was less than 130/85 mmHg was 10.8% in nondiabetics and 11.4% in diabetics. The average number of hypotensive agents used was 1.46 in nondiabetics and 1.52 in diabetics. Physicians prescribed more ACE inhibitors and alpha-blockers in diabetics than in nondiabetics, although Ca-antagonists were administered in more than 70% of patients irrespective of whether or not they had diabetes. In contrast, fewer beta-blockers and diuretics were administered to diabetics. These results suggest that although Japanese physicians are considering the effects of hypotensive agents on metabolism and renal function when they treat diabetic hypertensives, the achieved blood pressure in both hypertensives with and those without diabetes is insufficient, with only one of ten patients having a blood pressure less than 130/85 mmHg even among diabetics. Improved blood pressure control will therefore be needed to treat high risk groups such as patients with diabetes mellitus.

Cerebral oximetry for the detection of cerebral ischemia during temporary carotid artery occlusion

The near-infrared spectroscopy cerebral oximeter was assessed as a monitoring device for detecting and/or predicting cerebral ischemia during carotid endarterectomy (CEA) and the balloon occlusion test in 24 patients, 12 males and 12 females aged 28 to 77 years (mean 59.9 years). Tolerance testing of complete internal carotid artery (ICA) occlusion by balloon inflation for 20 minutes was performed in nine patients (cerebral aneurysm 6, neck tumor 3) and CEA was performed in 15 patients. The probe of the cerebral oximeter was placed on the forehead of the affected side and regional cerebral oxygen saturation (rSO2) was monitored continuously during all procedures. Stump pressure was measured just after ICA occlusion. Collateral circulation detected by digital subtraction angiography was classified into three groups: good, moderate, or poor. Stump pressure was 41-90 mmHg (mean 61.3 mmHg) in the good collateral circulation group, 40-43 mmHg (41.5 mmHg) in the moderate group, and 14-30 mmHg (23.8 mmHg) in the poor group. Change in rSO2 after ICA occlusion was +3.5(-)-4.2% (mean -1.6%) in the good collateral circulation group, -1.2(-)-6.6% (-3.2%) in the moderate group, and -2.4(-)-10.2% (-6.6%) in the poor group. Changes in rSO2 were significantly different between the good and poor collateral circulation groups (p < 0.01). A greater than 5% fall in rSO2 was observed in 0 of 15 patients in the good collateral circulation group, one of five in the moderate group, and three of four in the poor group. The cerebral oximeter is a useful, real-time, non-invasive method to measure brain oxygenation during CEA, skull base surgery, or other procedures which need to evaluate brain ischemia. A fall of greater than 10% from the rSO2 baseline value is dangerous, but less than 5% is safe.

Quantitative diversity of 67 kda protective antigen among serovar 2 strains of Erysipelothrix rhusiopathiae and its implication in protective immune response

Mouse monoclonal antibodies (MAbs), raised against the NaOH-extracted antigen of Erysipelothrix rhusiopathiae strain Kyoto (serovar 2), recognized two different epitopes on a single protein of molecular weight 67 kDa. The MAbs were classified as protective or non-protective against strain Fujisawa (serovar 1). In immunoblotting analysis using the MAbs, fifteen wild strains were shown to contain different amounts of 67 kDa protective antigen. Each formalin-killed whole cell vaccine (bacterin) prepared from the fifteen wild strains conferred different levels of protection against strain Fujisawa in mice. Bacterins prepared from wild strains with larger amounts of 67 kDa protective antigen tended to give high levels of antigen-specific antibody and better protection to mice. These results indicate that the amount of 67 kDa protective antigen which influences the induction of protective immune responses may vary substantially among the strains of E. rhusiopathiae (serovar 2).

Calcitonin receptor regulation and responsiveness to calcitonin in human osteoclast-like cells prepared in vitro using receptor activator of nuclear factor-kappaB ligand and macrophage colony-stimulating factor

Using mouse osteoclast-like cells (OCs), we have shown that short exposure to calcitonin (CT) resulted in prolonged reduction of CT binding by inhibiting de novo CT receptor (CTR) synthesis. Additionally, CT-treated OCs demonstrated resistance to CT rechallenge on the inhibitory effect of CT in osteoclastic bone resorption. There is, however, scant information on CT effects on human osteoclasts. In this study, we examined the features of CTR down-regulation and its recovery after short exposure to CT of human OCs. OCs were prepared by treatment of peripheral blood mononuclear cells in vitro with osteoclast differentiation factor and macrophage colony-stimulating factor. Treatment of OCs with salmon CT (sCT) and human CT (hCT) resulted in a dose-dependent reduction in [125I]sCT binding capacity. Continued receptor occupancy by ligand was excluded by using a glycine-acid washing procedure. Treatment with sCT reduced CTR messenger RNA expression, suggesting that CTR down-regulation is, at least partly, attributable to an inhibition of de novo CTR synthesis. To investigate the intracellular signal transduction pathways that mediate these effects, we examined the effects of activation of the protein kinase (PK)A, PKC, and Ca2+-calmodulin-dependent kinases. Treatment with PKC activators mimicked CT, whereas neither activation of PKA nor elevation of intracellular Ca2+ did so. We further investigated the intracellular signaling pathways responsible for the inhibitory effects of CT on bone resorption, which showed that treatment with PKC activators reproduced the effects of CT. These data suggest that the PKC pathway plays an important role in homologous CTR down-regulation, as well as inhibition of bone-resorbing activity by CT, in human OCs. Short exposure of OCs to CT (10(-9) M, 1 h) reduced [125I]sCT-specific binding for a prolonged period, as we have shown previously in mouse OCs. The reduced specific binding, CTR messenger RNA levels, and CT-sensitive adenylate cyclase responsiveness returned to the control levels by 96 h after removal of CT. These results strongly support the notion that escape from CT inhibition of osteoclastic bone resorption in humans is attributable to the development of resistance by OCs to CT. This study also showed that even short exposure to CT induced prolonged desensitization to CT rechallenge, although the OCs eventually regained responsiveness to sCT rechallenge.

Serial diffusion-weighted imaging in MELAS

Clinical features of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) resemble those of cerebral infarcts, but the pathogenesis of infarct-like lesions is not fully understood. To characterise these infarct-like lesions, we studied two patients with MELAS using diffusion-weighted (DWI) MRI before and after stroke-like episodes and measured the apparent diffusion coefficient (ADC) in the new infarct-like lesions. These gave high signal on DWI and had much higher ADC than normal-appearing regions. The ADC remained high even 30 days after a stroke-like episode then decreased in lesions, with or without abnormality as shown by conventional MRI. We speculate that early elevation of ADC in the acute or subacute phase reflects vasogenic rather than cytotoxic edema. The ADC of the lesions, which disappeared almost completely with clinical improvement, returned to normal levels, which may reflect tissue recovery without severe damage. To our knowledge, this is the first study of DWI in MELAS.

Antibacterial carbohydrate monoesters suppressing cell growth of Streptococcus mutans in the presence of sucrose

The growth-inhibitory effect of 23 carbohydrate monoesters synthesized by lipases and proteases were assayed to obtain antibacterial agents that suppress the cell growth of Streptococcus mutans. Among the carbohydrate esters synthesized, galactose and fructose laurates showed the highest growth-inhibitory effect, while the other analogs of hexose laurates showed no antibacterial activity, indicating that configuration of the hydroxyl group in carbohydrate moiety markedly affects the antibacterial activity. The cell growth of S. mutans was suppressed by fructose laurates even in the presence of sucrose. Thus, enzymatic synthesis of carbohydrate esters with different core structures has great potential for developing antibacterial agents applicable to food additives.

Influence of antigenic forms and adjuvants on protection against a lethal infection of Aujeszky's disease virus

The influence of antigenic forms and adjuvant types on protection against a lethal infection of Aujeszky's disease virus (ADV) in mice was investigated. Antiviral IgG2a antibody response against particulate (inactivated ADV) and soluble antigen (ADV solubilized with deoxychorate-Na) in approximate order of extent was ISA70>QS-21>positively charged liposome>negatively charged liposome>weak negatively charged liposome>ISA25>lablabside F saponin>aluminum phosphate gel>non adjuvant. Particulate antigen induced higher IgG2a antibody production than soluble antigen. Particulate antigen combined with ISA70, ISA25 or positively charged liposome gave 100, 50 and 40% protection to mice, respectively. In contrast, soluble antigen plus ISA70 conferred 30% protection on mice. Immunogens using the other adjuvants gave </=20% protection to mice. These results indicate that a combination of particulate antigen and an appropriate adjuvant effectively induces the production of antiviral IgG2a antibody and provides protection against a lethal ADV infection in mice.

Gallyas-positive argyrophilic and ubiquitinated filamentous inclusions in rapidly progressive motor neuron disease: immunohistochemical and electron microscopic studies

In an autopsy case of sporadic rapidly progressive lower motor neuron disease (MND), Gallyas-positive argyrophilic and ubiquitinated filamentous intracytoplasmic inclusions were found in the neurons. Clinically, 7 months prior to death, a 68-year-old woman experienced a history of rapidly progressive muscle weakness of all four extremities and bulbar sign, without sensory and autonomic disturbance. Two months later, she became unable to stand or walk. Four months after onset, she needed respiratory support, and subsequently died due to cardiorespiratory arrest. Neuropathological examinations revealed neuronal loss and associated gliosis in the lower motor neurons, except for ocular motor nuclei, Clark's column, and accessory cuneate nucleus, and tract degeneration was observed in the middle root zone of the posterior column and spinocerebellar tract. No Bunina bodies or Lewy body-like hyaline inclusions were found in the anterior horns. Gallyaspositive argyrophilic filamentous inclusions were found in the lower motor neurons and in nerve cells of the Clark's column, intermediate zone, posterior horn and accessory cuneate nucleus. These were positive with anti-ubiquitin antibody but negative with anti-tau (tau-2 and AT8) and neurofilament antibodies. Electron microscopic examinations disclosed randomly arranged tubular-like filamentous profiles, with a diameter of 12-14 nm, sometimes with amorphous granules in the perikaryon. This is the first report on the Gallyas-positive argyrophilic and ubiquitinated filamentous inclusions in neurons in MND.

A patient of hypogonadotropic hypogonadism accompanied by growth hormone deficiency and decreased bone mineral density who attained normal growth

We present here a rare case of hypopituitarism accompanied by growth hormone (GH) deficiency and hypogonadotropic hypogonadism, in which the patient attained normal height but was of eunuchoid appearance. A 23-year-old man who had not reached puberty was referred to Saitama Medical School for hormonal evaluation. Basal hormonal data and hormone-stimulating tests revealed impaired secretion of GH, gonadotropins and adrenocorticotropic hormone (ACTH). Serum levels of testosterone, estrone, estradiol and estriol were all below the detectable ranges. The patient's plasma ACTH responded to corticotropin releasing hormone, but not to insulin-induced hypoglycemia. Serum GH showed a minimal response to GH-releasing hormone, but was unresponsive to insulin-induced hypoglycemia. Serum luteinizing hormone and follicle stimulating hormone did not respond to luteinizing hormone-releasing hormone. The results were compatible with a diagnosis of hypothalamic hypopituitarism. Magnetic resonance images of the brain showed a small anterior pituitary, an ectopic posterior lobe and transection of the pituitary stalk. Although the patient showed signs of hypopituitarism, he finally attained normal height, possibly because of failed epiphyseal maturation. His bone mineral density was markedly reduced to 0.647 g/cm2 in the lumbar spine; this level was 61.7% of the average level of healthy young males. Our findings were compatible with a recently advocated view that estrogen is important in promoting epiphyseal fusion and in determining bone density in males as well as females.

Lipophilic HMG-CoA reductase inhibitor has an anti-inflammatory effect: reduction of MRNA levels for interleukin-1beta, interleukin-6, cyclooxygenase-2, and p22phox by regulation of peroxisome proliferator-activated receptor alpha (PPARalpha) in primary endothelial cells

We examined the effects of four 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (pravastatin, simvastatin, fluvastatin, and cerivastatin) on the production and expression of inflammatory cytokines and on enzyme expression involving prostaglandin and superoxide production in cultured human umbilical vein endothelial cells (HUVEC). All HMG-CoA reductase inhibitors significantly reduced interleukin-1beta and -6 mRNA expression and their protein levels in the culture medium, and also inhibited cyclooxygenase-2 mRNA expression and their protein levels. And these drugs induced peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma mRNA expression and their protein levels in HUVEC and hepatocyte. Moreover, the mRNA levels of p22phox, a 22-kD subunit and the protein levels of p47phox, a 47-kD subunit of nicotine adenine dinucleotide phosphate (NADPH) oxidase, was decreased by treatment with either simvastatin, fluvastatin or cerivastatin, and this effect was reversed by mevalonate, geranylgeraniol, farnesol, and cholesterol. The changes induced by HMG-CoA reductase inhibitors might be due to regulation of cellular cholesterol content level, cellular cholesterol metabolic pathway, and cellular PPARalpha activity, which was related with inflammation. This unique anti-inflammatory effect in addition to its hypolipidemic action, may be beneficial in preventing the vascular complications that are induced by hyperlipidemia.

Covalent modifier NEDD8 is essential for SCF ubiquitin-ligase in fission yeast

A ubiquitin-like modifier, NEDD8, is covalently attached to cullin-family proteins, but its physiological role is poorly understood. Here we report that the NEDD8-modifying pathway is essential for cell viability and function of Pcu1 (cullin-1 orthologue) in fission yeast. Pcu1 assembled on SCF ubiquitin-ligase was completely modified by NEDD8. Pcu1(K713R) defective for NEDD8 conjugation lost the ability to complement lethality due to pcu1 deletion. Forced expression of Pcu1(K713R) or depletion of NEDD8 in cells resulted in impaired cell proliferation and marked stabilization of the cyclin-dependent kinase inhibitor Rum1, which is a substrate of the SCF complex. Based on these findings, we propose that covalent modification of cullin-1 by the NEDD8 system plays an essential role in the function of SCF in fission yeast.

[Intrasellar epidermoid cyst]

We report a rare case of intrasellar epidermoid cyst. A 61-year-old man presented with complaints of the disturbance of consciousness and general fatigability. His laboratory data showed panhypopituitarism and MRI revealed the cystic tumor located at the intrasellar region. Tumor was removed by transsphenoidal approach and histological examination of the surgical specimen showed that the cyst wall was composed of the stratified squamous epithelium with keratohyaline granules.

Formation of acyl radical in lipid peroxidation of linoleic acid by manganese-dependent peroxidase from Ceriporiopsis subvermispora and Bjerkandera adusta

Lipid peroxidation by managanese peroxidase (MnP) is reported to decompose recalcitrant polycyclic aromatic hydrocabon (PAH) and nonphenolic lignin models. To elucidate the oxidative process, linoleic acid and 13(S)-hydroperoxy-9Z,11E-octadecadienoic acid [13(S)-HPODE] were reacted with MnPs from Ceriporiopsis subvermispora and Bjerkandera adusta and the free radicals produced were analyzed by ESR. When the MnPs were reacted with 13(S)-HPODE in the presence of Mn(II), H2O2 and tert-nitrosobutane (t-NB), the ESR spectrum contained a sharp triplet of acyl radical (aN = 0.81 mT). Formation of acyl radical was also observed in the reactions of Mn(III)-tartrate with 13(S)-HPODE and with linoleic acid, but the latter reaction occurred explosively after an induction period of around 30 min. Reactions of MnP with linoleic acid in the presence of Mn(II), H2O2 and t-NB gave no spin adducts while addition of t-NB after preincubation of linoleic acid with MnP/Mn(II)/H2O2 for 2 h gave spin adducts of carbon-centered (aN = 1.53 mT, aH = 0.21 mT) and acyl (aN = 0.81 mT) radicals. In contrast to linoleic acid, methyl linoleate and oleic acid were not peroxidized by MnP and chelated Mn(III) within a few hours, indicating that structures containing both the 1,4-pentadienyl moiety and a free carboxyl group are necessary for inducing the peroxidation in a short reaction time. These results indicate that MnP-dependent lipid peroxidation is not initiated by direct abstraction of hydrogen from the bis-allylic position during turnover but proceeds by a Mn(III)-dependent hydrogen abstraction from enols and subsequent propagation reactions involving the formation of acyl radical from lipid hydroperoxide. This finding expands the role of chelated Mn(III) from a phenol oxidant to a strong generator of free radicals from lipids and lipid hydroperoxides in lignin biodegradation.

Lack of association of the Ala45Thr variant in the BETA2/NEUROD1 with type 1 diabetes in Japanese

To evaluate the role of the Ala45Thr variant of BETA2/NEUROD1 in the development of type 1 or type 2 diabetes, we studied a Japanese population consisting of 383 control subjects, 234 type 1 diabetes patients and 160 type 2 diabetes patients. Both genotypewise and allelewise, there was no significant association of the variant with type 1 diabetes or type 2 diabetes in Japanese. Also, there were no significant differences in clinical characteristics with and without the variant. Our present results do not support a recent report which described an association of the Ala45Thr variant with type 1 diabetes in Japanese.

Destabilization of tumor necrosis factor-alpha mRNA by 5-alpha dihydrotestosterone in Jurkat cells

The effect of a male steroid hormone, 5DHT, on the expression of TNF-alpha was examined using a human leukemia T cell line, Jurkat. Cells were treated with 5DHT in the presence or absence of PHA, and RNA was isolated followed by a reverse transcriptase - mediated PCR (RT-PCR) to measure the steady state levels of TNF-alpha mRNA. The treatment of cells with 5DHT resulted in a 50% of decrease in the level of TNF-alpha mRNA compared to that in untreated conditions (basal level). A similar level of reduction of the message by 5DHT was also observed in PHA-stimulated cells. The reduction of the steady state levels of TNF-alpha mRNA in Jurkat cells was a result of destabilization of the gene as demonstrated by actinomycin D treatment; a half-life of TNF-alpha message in 5DHT treated cells and non-treated cells was 1 hr and 2.5 hr, respectively, whereas that in 5DHT/PHA and PHA-treated cells was 3hr and 6hr, respectively.

A case of renin-producing adrenocortical cancer

Here we report a case of a renin-producing adrenocortical carcinoma. A 57-year-old woman was referred to our hospital complaining of thirst and generalized muscle weakness. She was diagnosed as being hypertensive and diabetic with associated hypokalemia and she had a hard elastic mass with a diameter of 10 cm on the left side of her neck. An abdominal computed tomography scan revealed a suprarenal mass on the left side (8.5 x 8 x 6.5 cm). Endocrinological examination demonstrated a marked elevation in the patient's serum glucocorticoid and sex steroid hormones as well as plasma renin activity. Histological examination of a sample taken from the neck mass revealed a metastasis from an adrenal carcinoma, which was stained positively with antibodies against cytochrome P450 and renin, establishing the diagnosis of a renin-producing adrenocortical carcinoma. Trilostane was effective in reducing serum cortisol levels, but mitotane was ineffective.

Localization of oxidized HDL in atheromatous plaques and oxidized HDL binding sites on human aortic endothelial cells

We examined the localization of oxidized high-density lipoprotein (HDL) in atheromatous plaques and the oxidized HDL binding sites on endothelial cells. Histochemical analysis using CuSO4-oxidized HDL-specific 9F5-3a antibody indicated the presence of oxidized HDL in the intima of atheromatous plaques in human abdominal aortae. The cell surface binding of 125I-oxidized HDL to cultured human aortic endothelial cells (HAEC) was saturable, with an apparent dissociation constant (Kd) of 1.43 micromol/L. Competition for 125I-oxidized HDL binding was strong for oxidized HDL, moderate for native HDL and low for acetylated low-density lipoprotein (LDL) or oxidized LDL. Using oxidized HDL as a ligand for blotting, a major 130-kDa band was detected in HAEC. These results suggest that oxidized HDL and its putative binding protein are present in atheromatous plaques and endothelial cells, respectively.

A Clostridium perfringens hem gene cluster contains a cysG(B) homologue that is involved in cobalamin biosynthesis

The hem gene cluster, which consists of hemA, cysG(B), hemC, hemD, hemB, and hemL genes, and encodes enzymes involved in the biosynthetic pathway from glutamyl-tRNA to uroporphyrinogen III, has been identified by the cloning and sequencing of two overlapping DNA fragments from Clostridium perfringens NCTC8237. The deduced amino acid sequence of the N-terminal region of C. perfringens HemD is homologous to those reported for the C-terminal region of Salmonella typhimurium CysG and Clostridium josui HemD. C. perfringens CysG(B) is a predicted 220-residue protein which shows homology to the N-terminal region of S. typhimurium CysG. Disruption of the cysG(B) gene in C. perfringens strain 13 by homologous recombination reduced cobalamin (vitamin B12) levels by a factor of 200. When grown in vitamin B12-deficient medium, the mutant strain showed a four-fold increase in its doubling time compared with that of the wild-type strain, and this effect was counteracted by supplementing the medium with vitamin B12. These results suggest that C. perfringens CysG(B) is involved in the chelation of cobalt to precorrin II as suggested for the CysG(B) domain of S. typhimurium CysG, enabling the synthesis of cobalamin.

Missense variations of the gene responsible for Wolfram syndrome (WFS1/wolframin) in Japanese: possible contribution of the Arg456His mutation to type 1 diabetes as a nonautoimmune genetic basis

Recently, a novel gene for a putative transmembrane protein (WFS1/wolframin) was found to be mutated in patients with Wolfram syndrome or DI-DM-OA-D (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness) syndrome. It is suggested that the WFS1 protein is important in the survival of islet beta-cells. We studied the WFS1 gene in a Japanese population to assess its possible role in common type 1 diabetes. Mutation screening revealed four missense mutations; R456H, G576S, H611R, and I720V. By genetic association studies of 185 type 1 diabetes patients and 380 control subjects, we found that R456H was significantly increased in the type 1 diabetes group compared to the control group (P = 0.0005); H611R and I720V were also significantly increased with weaker significance. Furthermore, in patients with the R456H mutation, type 1 diabetes-resistant HLA-DRB1 alleles (DRB1*0406, 1501, and 1502) were significantly increased compared to mutation-negative patients while susceptible DRB1*0901 was significantly decreased. Frequencies of autoimmunity characteristics (ICA or GAD-Ab positiveness and combination of autoimmune thyroid disease) were decreased in the R456H-positive patients compared to the R456H-negative patients. These data suggest that the WFS1 gene may have a role in the development of common type 1 diabetes as a nonautoimmune genetic basis.

Age-specific effects of noradrenergic alpha-2 agonist clonidine on the development of amygdaloid kindling in developing rats

The effects of clonidine on the development of amygdaloid kindling were studied in rats of various ages (14, 21, 28 and 70 postnatal days). Administration of clonidine (0.2, 0.5 mg/kg i.p.) caused a significant retardation of kindling development in the 28-day-old rats as well as in the adult rats, whereas, in the 14-day-old rats, the development of kindling was significantly facilitated by clonidine. No significant effect of clonidine was observed in the 21-day-old rats. These results indicate that in rats the effects of clonidine on the development of amygdaloid kindling vary during development.

Protective roles of endogenous carbon monoxide in neointimal development elicited by arterial injury

We reported that carbon monoxide (CO) generated through heme oxygenase (HO) inhibits mitogen-induced proliferation of vascular smooth muscle cells (VSMCs). We report that balloon injury induces HO-1, the stress-inducible isozyme of HO, in VSMCs and inhibits neointimal formation through the action of endogenous CO. Northern blot analysis and immunohistochemistry revealed that HO-1 is markedly induced in the media as early as 1 day after injury, whereas only a little expression was detected in the intact carotid artery. The neointimal proliferative changes were augmented or inhibited by the HO inhibitors or inducer, respectively, and effects of these interventions were not altered by suppression of endogenous nitric oxide (NO), if any. To elucidate the mechanisms by which HO controls the proliferative changes, effects of alterations in the HO reaction were examined by determining angiotensin II-elicited VSMC proliferation in vitro: the HO inducer attenuated and its inhibitor restored the proliferative response to angiotensin II (1 nM and 100 nM). Hemoglobin, a reagent trapping both NO and CO, but not met-hemoglobin, which can capture NO but not CO, augmented the proliferative response. These data suggest that endogenous CO serves as a protective factor that limits the excessive VSMC proliferation associated with vascular diseases.