Angiotensin II stimulates mitogen-activated protein kinases and protein synthesis by a Ras-independent pathway in vascular smooth muscle cells

Angiotensin II (ANG II), a potent hypertrophic factor of vascular smooth muscle cells (VSMC), induces activation of the ras protooncogene product (Ras) and mitogen-activated protein (MAP) kinases and subsequent stimulation of protein synthesis in VSMC. In the present study, we examined whether Ras activation is required for ANG II-induced MAP kinase activation and stimulation of protein synthesis in cultured rat VSMC. Pretreatment with tyrosine kinase inhibitors, genistein and herbimycin A, or a putative phosphatidylinositol 3-kinase inhibitor, wortmannin, completely blocked ANG II-induced Ras activation, whereas neither of them had an effect on ANG II-induced MAP kinase activation. Adenovirus-mediated expression of a dominant negative mutant of Ha-Ras completely inhibited ANG II-induced Ras activation but failed to inhibit MAP kinase activation and stimulation of protein synthesis by this vasoconstrictor. These results indicate that ANG II stimulates MAP kinases and protein synthesis by a Ras-independent pathway in VSMC.

Motor cortical reflex myoclonus: a case study with MEG

Cortical reflex myoclonus usually depends for its generation on the hyperexcitability of sensory cortex, which manifests itself as an enhanced somatosensory evoked potential (SEP). A 25-year-old female, presenting with involuntary jerky dorsiflexion of the left foot, was found to have cortical reflex myoclonus which was aggravated during intended movements. The jerks were also elicited by electrical stimulation of the posterior tibial nerve, although the SEP evoked by the same stimulus was normal in latency and amplitude. Both the spontaneous spikes and the premyoclonus spike demonstrated by jerk-locked back averaging were localized to the superior frontal gyrus, just anterior to the paracentral sulcus. Paired-pulse magnetic stimulation disclosed lack of inhibition in the right hemisphere leg motor area, whereas the excitability of sensory cortex as studied by paired SEP testing was normal. This suggests that the myoclonus was caused mainly by enhanced excitability of the motor cortex and that this alone was enough for the production of long loop reflexes. We propose to designate this type of cortical myoclonus as motor cortical reflex myoclonus. It is generated in the motor cortex, but is at the same time stimulus-sensitive.

A dtsR gene-disrupted mutant of Brevibacterium lactofermentum requires fatty acids for growth and efficiently produces L-glutamate in the presence of an excess of biotin

A dtsR gene encoding a homolog of the beta subunit of some biotin-containing enzymes suppresses a detergent-sensitive mutation of Brevibacterium lactofermentum (E. Kimura et al., 1996, Biosci. Biotech. Biochem. 60, 1565-1570), which has been used for the fermentative production of L-glutamate. When the dtsR gene was disrupted, the organism exhibited strict fatty acid auxotrophy; oleate or oleate ester, but not palmitate ester or stearate ester, supported the growth of the delta dtsR mutant. Immunoblotting with an anti-DtsR antibody revealed that no intact DtsR was present in the cytosol of the delta dtsR mutant. In the presence of an excess of biotin, the wild type strain did not produce L-glutamate whereas the delta dtsR mutant efficiently produced it. The mechanism underlying the efficient production of L-glutamate by the delta dtsR mutant is discussed as to the possible role of dtsR in fatty acid metabolism.

Cutaneous vasculitis in Behçet's disease: a clinical and histopathologic study of 20 patients

BACKGROUND

Despite the frequency of small vessel vasculitis in skin lesions of Behçet's disease (BD), BD is classified as a neutrophilic dermatosis.

OBJECTIVE

Our goal was to determine whether the various cutaneous manifestations of BD are secondary to cutaneous vasculitis.

METHODS

Twenty-three specimens with histologically proven necrotizing vasculitis from 20 of 42 patients with BD were investigated.

RESULTS

The cutaneous vasculitic manifestations were characterized as erythema nodosum-like eruptions, palpable purpura, hemorrhagic blisters, infiltrated erythema, Sweet's syndrome-like eruptions, papulopustular lesions, and extragenital ulcerations. Combinations of various skin lesions were commonly seen in the same patient. Venous vessels in the entire dermis to the subcutis were affected with sparing of arterial vessels from middermis to subcutis. Histologic features included leukocytoclastic vasculitis in seven and lymphocytic vasculitis in 13 patients with extensive to focal localized fibrinoid necrosis of vessel walls.

CONCLUSION

Cutaneous vasculitis in BD is predominantly venulitis or phlebitis. Approximately half (48%; 20 of 42) of BD patients with cutaneous lesions had either lymphocytic (31%; 13 of 42) or leukocytoclastic vasculitis (17%; 7 of 42). We suggest that BD be considered as a vasculitis-associated disease separate from the neutrophilic dermatoses.

Immunoblot analysis of autoantigens in localized pemphigoid and pemphigoid nodularis

We analyzed circulating antibodies in sera from patients with localized pemphigoid and pemphigoid nodularis, two variants of bullous pemphigoid, by means of western immunoblotting of human epidermal extracts and the recombinant protein of NC16a domain of the 180 kD bullous pemphigoid antigen. NC16a domain is now considered to be the most pathogenic site of bullous pemphigoid. Compared with the results of typical bullous pemphigoid patients, localized pemphigoid sera detected the 180 kD bullous pemphigoid antigen less frequently, and sera from both localized pemphigoid and pemphigoid nodularis showed a lower end point of titer of antibodies to NC16a domain. These results suggest that atypical clinical features of the two bullous pemphigoid variants may be related with low titer of autoantibodies to 180 kD bullous pemphigoid antigen, particularly to NC16a domain.

Temocaprilat, a novel angiotensin-converting enzyme inhibitor, is excreted in bile via an ATP-dependent active transporter (cMOAT) that is deficient in Eisai hyperbilirubinemic mutant rats (EHBR)

Temocapril x HCl (alpha-((2S,6R)-6-[(1S)-1-ethoxy-carbonyl-3-phenyl-propyl]amino-5-oxo-2- (2-thienyl)perhydro-1,4-thiazepin-4-yl)acetic acid hydrochloride) is a novel prodrug of an angiotensin-converting enzyme (ACE) inhibitor. Unlike many other ACE inhibitors, its pharmacologically active metabolite,temocaprilat, is excreted predominantly in bile. To investigate the mechanism for the biliary excretion of temocaprilat, we performed in vivo and in vitro experiments using mutant Eisai hyperbilirubinemic rats EHBR) whose canalicular multispecific organic anion transporter (cMOAT) is hereditarily defective. Biliary clearance of temocaprilat after i.v. administration of [14C]temocapril x HCl (1.0 mg/kg) in EHBR was significantly lower than that in Sprague-Dawley rats (5.00 ml/min/kg for Sprague-Dawley rats vs. 0.25 ml/min/kg for EHBR). The uptake of temocaprilat into canalicular membrane vesicles (CMVs) prepared from Sprague-Dawley rats was stimulated in the presence of ATP, whereas little stimulation was observed in CMVs from EHBR. The initial uptake rate of ATP-dependent transport of temocaprilat showed saturation kinetics; we obtained an apparent V(max) value of 1.14 nmol/min/mg protein and a K(m) value 92.5 microM. ATP-dependent transport of temocaprilat was competitively inhibited by 2,4-dinitrophenyl-S-glutathione, a typical substrate for cMOAT with an inhibition constant (K(i)) of 25.8 microM. The K(m) value for the uptake of 2,4-dinitrophenyl-S-glutathione into CMVs (K(m) = 29.6 microM) was consistent with this K(i) value. In addition, the ATP-dependent uptake of 2,4-dinitrophenyl-S-glutathione was inhibited by temocaprilat in a concentration-dependent manner. Active forms of some ACE inhibitors (benazepril, cilazapril, delapril, enalapril and imidapril) did not affect the transport of temocaprilat into CMVs even at concentrations as high as 200 microM. These data suggest that temocaprilat is effectively excreted in bile via cMOAT that is deficient in EHBR and that many of other ACE inhibitors have low affinity for cMOAT.

[Bilateral leg ulcers with pathologic evidence of small vessel vasculitis by skin biopsy during hydroxyurea therapy of chronic myelogenous leukemia]

We report a 45-year-old male with chronic myelogenous leukemia (CML) who experienced skin ulcers of the left lateral malleolus and dorsum of both feet. He had been treated with hydroxyurea (HU) for 2 years. His leg ulcers improved after HU was discontinued. Skin biopsy of the ulcerated lesion revealed that the lesion is compatible with small vessel vasculitis, but circulating immune complexes (C1q, anti-C3d antibody) were negative. Although the precise mechanism of the skin ulcer is unknown, we must take into consideration the skin changes were secondary to hydroxyurea therapy in myeloproliferative disorders.

Blood cyst of the pulmonary valve in an adult: report of a case and review of the literature

We report a case of a blood cyst originating from the pulmonary valve cusp of a 43-year-old Japanese woman with pulmonary stenosis. Cineangiography revealed a pedunculated tumor on the arterial surface of the pulmonary valve. It was successfully removed by a transpulmonary artery approach. The cyst contained old blood and calcified thrombi, and its wall consisted of collagenous fibrous tissue. Immunohistochemically, a monolayer of flat cells lining the cyst was confirmed as endothelium using antibodies to von Willebrand factor and CD34, as well as UEA-I lectin. To the best of our knowledge, blood cysts of the pulmonary valve are rare and only 10 such cases have been reported, including six pediatric cases. This case is the oldest and fifth adult patient with a blood cyst found on the pulmonary valve. A possible histogenesis is discussed.

Regulation of inducible nitric oxide synthase expression in L6 rat skeletal muscle cells

Cytokine-stimulated expression of inducible type of nitric oxide synthase (iNOS) seems to be regulated by various signal pathways in a cell-specific manner. In this study, we examined how it was regulated in L6 rat skeletal muscle cells. In L6 cells, the combination of interleukin-1 beta and interferon-gamma induced a marked accumulation of nitrite, a stable metabolite of nitric oxide. In parallel with this reaction, iNOS mRNA expression was achieved at a maximum between 3 and 6 h, and iNOS protein was detectable at 6 h and peaked at 24 h after stimulation. Tyrosine kinase inhibitors, herbimycin A, and genistein suppressed cytokine-induced iNOS expression and nitrite production. Forskolin, an adenosine 3',5'-cyclic monophosphate-dependent protein kinase (PKA) activator, and phorbol 12-myristate 13-acetate, a protein kinase C (PKC)-activating phorbol ester, enhanced these cytokine-induced reactions. These results indicate that iNOS expression by cytokines is mediated via a protein tyrosine kinase-dependent pathway and is positively modulated by both PKA- and PKC-dependent pathways in this cell type.

Mixed-cryoglobulinemia associated with cutaneous vasculitis and pulmonary symptoms

A 45-year-old Japanese man with Sjögren's syndrome developed recurrent skin ulcers, palpable purpura, and dyspnea. Serum mixed-type cryoglobulin level was elevated. A biopsy of his skin lesion showed the characteristic leukocytoclastic vasculitis of mixed-type cryoglobulinemia. Dyspnea, skin ulcers, and purpura resolved along with a reduction in the serum cryoglobulin level after prednisolone administration. This patient demonstrated cryoglobulinemia-associated vasculitis, as well as possible cryoglobulinemia-associated pulmonary symptoms.

Regulation of nitric oxide synthase gene expression by cytokines

Evidence is presented that not only macrophage type of NO synthase but also endothelial constitutive type of NO synthase genes are regulated by a variety of exogenous stimuli including cytokines. It is possible that pathophysiological concentrations of TNF-alpha noted in some patients with congestive heart failure may be sufficient to decrease levels for the constitutive form of NO synthase and increase those for the inducible form of NO synthase. Interestingly, chronic exercise in dogs was demonstrated to increases coronary vascular NO production and steady-state mRNA levels of ecNO synthase. Endogenous NO plays a crucial role in modulating vascular tone and inhibiting interactions of the vessel wall with circulating blood elements such as platelets, monocytes and neutrophils. It is possible that alterations in its synthesis or activity may play an important role in some cardiovascular disorders including congestive heart failure. Further studies of the pathophysiological significance of NO in specific experimental and clinical settings of congestive heart failure may provide a basis for improved therapeutic measures to enhance the synthesis or effect of endogenous NO, or to supplement its activity with exogenous NO donors or superoxide scavengers.

Molecular cloning of the Corynebacterium glutamicum ('Brevibacterium lactofermentum' AJ12036) odhA gene encoding a novel type of 2-oxoglutarate dehydrogenase

The Corynebacterium glutamicum ('Brevibacterium lactofermentum' AJ12036) odhA gene, encoding 2-oxoglutarate dehydrogenase (E1o subunit of the 2-oxoglutarate dehydrogenase complex), has been isolated and identified as an homologous counterpart of the Escherichia coll sucA and Bacillus subtilis odhA genes. The nucleotide sequence of a 4394 bp chromosomal fragment containing the C. glutamicum odhA gene was determined. The odhA gene comprised 3771 bp (1257 codons, including the initiation codon) and a molecular mass of 138656 Da was predicted for the OdhA polypeptide. Northern blot analysis revealed a 3.9 kb transcript. The size of the transcript, together with the presence of a rho-independent terminator-like structure, suggests that C. glutamicum odhA is monocistronic. Cells harbouring plasmids carrying C. glutamicum odhA showed a threefold increase in specific 2-oxoglutarate dehydrogenase complex activity and expression of a protein with an apparent molecular mass of 136 kDa, in good agreement with the predicted size of the OdhA polypeptide. The C-terminal region of the C. glutamicum OdhA protein shows strong sequence similarity to E1os from other organisms. C. glutamicum OdhA has an N-terminal extension not found in previously reported E1os. The amino acid sequence of this extension shows similarity to that of the C-terminal region of dihydrolipoamide S-succinyltransferase (E2o) subunits of 2-oxoglutarate dehydrogenase complexes and dihydrolipoamide S-acetyltransferase (E2p) subunits of pyruvate dehydrogenase complexes. It suggests that the C. glutamicum odhA gene might encode a novel bifunctional protein with E1o and E2o activities.

Adrenomedullin augments inducible nitric oxide synthase expression in cytokine-stimulated cardiac myocytes

BACKGROUND

Plasma levels of adrenomedullin are increased in patients with congestive heart failure, but there has been no report concerning the effects of adrenomedullin on the heart. We investigated the effects of adrenomedullin on NO synthase activity in cardiac myocytes.

METHODS AND RESULTS

We measured the production of nitrite, a stable metabolite of NO, in cultured neonatal rat cardiac myocytes with the Griess reagent. Inducible NO synthase mRNA and protein expression were assayed by Northern and Western blotting, respectively. Incubation of the cultures with interleukin-1 beta (10 ng/mL) for 24 hours caused a significant increase in nitrite accumulation. Adrenomedullin significantly augmented nitrite production by interleukin-1 beta-stimulated but not by unstimulated cardiac myocytes in a dose-dependent manner (10(-10) to 10(-6) mol/L). The adrenomedullin-induced nitrite production by interleukin-1 beta-stimulated cells was accompanied by increased inducible NO synthase mRNA and protein expression. In the presence of dibutyryl cAMP, the interleukin-1 beta-induced nitrite accumulation was increased further, but the stimulatory effect of adrenomedullin on nitrite production was abolished. Adrenomedullin dose-dependently increased intracellular cAMP levels in cardiac myocytes. Addition of the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP[8-37] to the culture dose-dependently inhibited both cAMP and NO generation stimulated by adrenomedullin.

CONCLUSIONS

These results indicate that adrenomedullin acts on cardiac myocytes and augments NO synthesis in these cells under cytokine-stimulated conditions, at least partially through a cAMP-dependent pathway.

Increasing cAMP antagonizes hypertrophic response to angiotensin II without affecting Ras and MAP kinase activation in vascular smooth muscle cells

Angiotensin II (Ang II), a potent hypertrophic factor for vascular smooth muscle cells (VSMC), induces activation of the ras proto-oncogene product (Ras) and mitogen-activated protein (MAP) kinases, and tyrosine phosphorylation of a focal adhesion-associated protein, paxillin. Forskolin, a direct activator of adenylate cyclase, and dibutyryl cAMP (Bt2 cAMP), a membrane permeable cAMP analogue, potently inhibited Ang II-stimulated protein synthesis. However, they did not inhibit Ang II-induced activation of Ras and MAP kinases. Although both forskolin and Bt2 cAMP potently reduced background tyrosine phosphorylation of paxillin, they allowed Ang II to induce the same reaction. These results indicate that increasing cAMP antagonizes the hypertrophic response to Ang II without affecting Ras and MAP kinase activation in VSMC and suggest that it does not interrupt signaling from the Ang II receptor to focal adhesions.

Molecular cloning of a novel gene, dtsR, which rescues the detergent sensitivity of a mutant derived from Brevibacterium lactofermentum

Several strains of Corynebacterium and Brevibacterium are known for their ability to secrete large amounts of amino acids, especially L-glutamate. We focused on the mechanism of L-glutamate secretion triggered by a detergent, namely polyoxyethylenesorbitan monopalmitate (PESP). A mutant strain, AJ11060, derived from Brevibacterium lactofermentum ATCC 13869 indicates the sensitivity to PESP. A multicopy suppresser gene that compliments the sensitivity of AJ11060 to the detergent was derived from a gene library of B. lactofermentum AJ12036. A 2855-bp DNA fragment was cloned and sequenced. An open reading frame was found that coded for the rescuer gene of the sensitivity to PESP of AJ11060 and was designated dtsR. The expression of the dtsR gene in B. lactofermentum was confirmed by using anti-DtsR antibody. The deduced DtsR protein indicated significant homology with some biotin enzymes such as the beta chain of propionyl-CoA carboxylase from rat (48.3%) and human (48.7%), or a 12S chain of methylmalonyl-CoA carboxyltransferase from Propionibacterium freudenreichii (43.1%).

Gadolinium-enhanced MR imaging of the wrist in rheumatoid arthritis: value of fat suppression pulse sequences

OBJECTIVE

To determine the usefulness of fat-suppressed gadolinium (Gd)-enhanced MR imaging of the wrist in patients with rheumatoid arthritis (RA).

DESIGN AND PATIENTS

Fat-suppressed Gd-enhanced T1-weighted spin-echo (SE) images were obtained and compared with other standard techniques in 38 wrists of 27 patients (22-77 years) with RA. Scoring based on the degree of synovial enhancement of each joint was developed and the total scores (J-score) were correlated with radiographic stage, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and symptomatic change in the follow-up study.

RESULTS

Synovial proliferations showed marked enhancement in all the wrists. In addition, contrast enhancement in the bone marrow and tenosynovium was seen in 36 and eight wrists respectively. Fat-suppressed Gd-enhanced T1-weighted images demonstrated these abnormalities better than other techniques. The J-scores correlated well with values of CRP (P = 0.0034), but not with radiographic stages and ESR.

CONCLUSION

Fat-suppressed Gd-enhanced T1-weighted SE images can clearly demonstrate most of the essential lesions in RA including the proliferative synovium, bone erosion, bone marrow inflammatory change, and tenosynovitis. Scoring based on the extent of Gd-enhancement of synovium can be useful in the assessment of the inflammatory status.

Angiotensin II type 1 receptor-mediated activation of Ras in cultured rat vascular smooth muscle cells

Angiotensin II (ANG II), a potent growth-promoting factor of vascular smooth muscle cells (VSMC), induces activation of mitogen-activated protein (MAP) kinases and subsequent expression of the c-fos protooncogene in VSMC. However, it remains obscure whether ANG II induces activation of the ras protooncogene product (Ras), and if it does, whether Ras is involved in signaling from the ANG II receptor to the MAP kinase pathway in VSMC. In cultured VSMC, ANG II activated Ras comparably to epidermal growth factor. ANG II-induced Ras activation was detectable within 1 min and maximal at 2-5 min. The ANG II type 1 (AT1) receptor antagonist, CV-11974, completely inhibited this reaction. Pertussis toxin treatment of VSMC inhibited ANG II-induced Ras activation by approximately 70% but had no effect on ANG II-induced MAP kinase activation and c-fos expression. These results indicate that ANG II activates Ras via AT1 receptors, which are predominantly linked to a G protein of the Gi subfamily in VSMC1 and suggest that Ras activation may not be a prerequisite for ANG II-induced MAP kinase activation and c-fos expression in this cell type.

A novel subepidermal blistering disease with autoantibodies to a 200-kDa antigen of the basement membrane zone

Several components of the basement membrane zone (BMZ) have been identified as antigenic targets in autoimmune bullous diseases. We report a novel disease with autoantibodies to a BMZ antigen that is different from the targets described so far. The patient suffering from this disorder showed tense bullae and severe mucous membrane involvement rapidly responding to oral tetracyclines and colchicine. Histopathologic findings resembled those of dermatitis herpetiformis. Direct immunofluorescence microscopy showed linear deposits of IgG and C3 at the BMZ. By indirect immunofluorescence studies on split human skin, using both 1 M NaCl and suction blistering for dermal-epidermal separation, IgG antibodies localized exclusively to the dermal side of the split. The antibodies were mainly of the IgG4 subclass. By Western blot analysis of epidermal and dermal extracts, the patient's serum unequivocally reacted with a dermal antigen of 200 kDa. It did not recognize bullous pemphigoid antigens, the autoantigen of epidermolysis bullosa acquisita, purified preparations of laminin-1 and laminin-5, or the recently described 105-kDa BMZ antigen. By immunoblotting of concentrated conditioned SCC-25 medium, the patient's antibodies reacted with a band of 200 kDa and several hands of lower molecular weight. No reactivity was seen with extracts of cultured human fibroblasts. By indirect immunogold electron microscopy, immunoreactants localized to the lower lamina lucida. After clearance of skin lesions, both indirect immunofluorescence and Western blot analysis became negative. This patient suffers from a novel autoimmune bullous disease with autoantibodies to a 200-kDa antigen of the BMZ.

Two cases of atypical bullous disease showing linear IgG and IgA deposition in the basement membrane zone

Patients showing coexistent linear IgG and IgA deposition along the basement membrane zone on direct immunofluorescence have been described as either bullous pemphigoid, epidermolysis bullosa acquisita, linear IgA bullous dermatosis, or cicatricial pemphigoid, depending on the clinical features and laboratory findings. In the present report, we describe two cases showing atypical clinical features distinct from those of other known bullous diseases. No circulating antibodies were detected by indirect immunofluorescence of normal human skin. Indirect immunofluorescence of 1 M NaCl split skin revealed IgG and/or IgA antibodies reactive with the dermal side of the split. Immunoblotting of normal human epidermal and dermal extracts showed no apparent reactivity with known autoantigens. The results suggest that there may be a unique and distinct bullous disease with linear IgG and IgA deposition at the basement membrane zone.

A novel subepidermal blistering disease with autoantibodies to a 200-kDa antigen of the basement membrane zone

Several components of the basement membrane zone (BMZ) have been identified as antigenic targets in autoimmune bullous diseases. We report a novel disease with autoantibodies to a BMZ antigen that is different from the targets described so far. The patient suffering from this disorder showed tense bullae and severe mucous membrane involvement rapidly responding to oral tetracyclines and colchicine. Histopathologic findings resembled those of dermatitis herpetiformis. Direct immunofluorescence microscopy showed linear deposits of IgG and C3 at the BMZ. By indirect immunofluorescence studies on split human skin, using both 1 M NaCl and suction blistering for dermal-epidermal separation, IgG antibodies localized exclusively to the dermal side of the split. The antibodies were mainly of the IgG4 sub-class. By Western blot analysis of epidermal and dermal extracts, the patient's serum unequivocally reacted with a dermal antigen of 200 kDa. It did not recognize bullous pemphigoid antigens (the autoantigen of epidermolysis bullosa acquisita), purified preparations of laminin-1 and laminin-5, or the recently described 105-kDa BMZ antigen. By immunoblotting of concentrated conditioned SCC-25 medium, the patient's antibodies reacted with a band of 200 kDa and several bands of lower molecular weight. No reactivity was seen with extracts of cultured human fibroblasts. By indirect immunogold electron microscopy, immunoreactants localized to the lower lamina lucida. After clearance of skin lesions, both indirect immunofluorescence and Western blot analysis became negative. This patient suffers from a novel autoimmune bullous disease with autoantibodies to a 200-kDa antigen of the BMZ.

Clinical significance of abnormal postexercise systolic blood pressure response in patients with hypertrophic cardiomyopathy

The clinical significance of abnormal postexercise systolic blood pressure (SBP) response in patients with hypertrophic cardiomyopathy (HCM) was assessed by treadmill exercise testing in 30 normal subjects and 96 patients with HCM. SBP recovery ratios were derived by dividing the SBP at 1 and 3 min after exercise by the peak exercise SBP. The upper normal limit of the SBP ratio was defined by two standard deviations (SD) from the mean in 30 normal subjects. A postexercise SBP ratio that exceeded the upper normal limits of the SBP ratio was considered to be an abnormal SBP response in patients with HCM. Twenty-seven (28%) of 96 patients with HCM showed an abnormal SBP response. Compared with the normal SBP response group (69 cases) among patients with HCM, the abnormal SBP response group had lower SBP response during exercise (22 +/- 25 vs 62 +/- 26 mmHg : mean +/- 1 SD, p < 0.05), more prolonged QRS width (110 +/- 21 vs 92 +/- 20 msec, p < 0.05), higher incidences of ventricular tachycardia (12 vs 7 cases, p < 0.001), and sudden death (7 vs 0 cases, p < 0.0001). The defect area of Tl-201 myocardial scintigraphy was more extensive in the abnormal SBP response group (2.9 +/- 1.7 segments) than in the normal SBP response group (1.1 +/- 1.3 segments, p < 0.05). During atrial pacing (120/min), pulmonary artery wedge pressure was slightly elevated from 10 +/- 2 (at rest) to 14 +/- 3 mmHg (during pacing) (p<0.001), cardiac index showed no significant changes, and time constant T was shortened from 58 +/- 13 to 48 +/- 10 msec (p < 0.001) in the normal SBP response group, but in the abnormal SBP response group pulmonary artery wedge pressure was highly elevated from 12 +/- 5 to 20 +/- 3 mmHg (p < 0.0001), cardiac index was decreased from 2.5 +/- 0.7 to 2.1 +/- 0.6 l/min/m2 (p < 0.05), and the time constant T had no significant changes. These observations suggest that patients with HCM and abnormal postexercise SBP response have an abnormal cardiac response during exercise and extensive myocardial damage.

Intravascular gas within an ovarian tumor: a CT sign of ovarian torsion

A case of twisted ovarian tumor with intravascular gas is presented, and the mechanism of the gas formation is discussed. On the basis of the probable mechanism of gas formation observed in dead fetuses, the gas seen in the present case is considered to have been oxygen released from trapped oxyhemoglobin within the tumor vessels. "Intravascular gas" within an ovarian tumor, although extremely rare, is diagnostic of ovarian torsion.

Angiotensin II augments cytokine-stimulated nitric oxide synthesis in rat cardiac myocytes

BACKGROUND

Nitric oxide (NO) has been shown to modulate cardiac function. We investigated the effect of angiotensin II (Ang II) on NO synthase activity in cardiac myocytes.

METHODS AND RESULTS

Using the Griess reagent, we measured the production of nitrite, a stable metabolite of NO, by cultured neonatal rat cardiac myocytes. The expression of inducible NO synthase (iNOS) mRNA was assayed by Northern blotting. Incubation of cardiac myocytes for 24 hours with interleukin-1 beta (IL-1 beta) caused a significant increase in NO production. Ang II significantly augmented NO synthesis in IL-1 beta-stimulated but not in unstimulated cells in a dose-dependent manner. The angiotensin type I receptor antagonist CV 11974 inhibited the effect of Ang II dose-dependently. Simultaneous incubation of Ang II with NG-monomethyl-L-arginine or actinomycin D also completely inhibited the effect of Ang II. The Ang II-induced NO production by IL-1 beta-stimulated cells was accompanied by increased iNOS mRNA accumulation. Phorbol 12-myristate 13-acetate (PMA) also augmented NO synthesis in IL-1 beta-stimulated but not in unstimulated cells in a dose-dependent manner. The protein kinase C inhibitor calphostin C dose-dependently blocked the effect of Ang II. After protein kinase C activity was functionally depleted by treatment of cells with PMA for 24 hours, Ang II did not augment IL-1 beta-induced NO production.

CONCLUSIONS

These results indicate that Ang II upregulates IL-1 beta-induced iNOS expression in cardiac myocytes, which is mediated at least partially via activation of protein kinase C.