In vitro evaluation of the antimicrobial properties of terpinen-4-ol on apical periodontitis-associated bacteria

Manuka oil and tea tree oil are essential oils with known antibacterial properties that are believed to be caused by one main component: terpinen-4-ol. Terpinen-4-ol has potent antibacterial activity against caries-related microorganisms. However, few studies have investigated the antimicrobial effects of terpinen-4-ol on bacteria in apical periodontitis. Thus, the objective of the present study was to evaluate the antibacterial and antibiofilm potential of terpinen-4-ol against Enterococcus faecalis, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum, which have all been detected in apical periodontitis. The minimum inhibitory and minimum bactericidal concentrations of terpinen-4-ol were determined to assess its activity against biofilms. The minimum inhibitory concentration of terpinen-4-ol was 0.25% against E. faecalis and F. nucleatum, 0.05% against P. gingivalis, and 0.1% against P. intermedia. The minimum bactericidal concentration of terpinen-4-ol was 1.0% against E. faecalis, 0.2% against P. gingivalis and P. intermedia, and 0.5% against F. nucleatum. In the biofilm evaluations, all terpinen-4-ol-treated bacteria had significant reductions in biofilm viability compared with controls in experiments assessing attachment inhibitory activity. Furthermore, structural alterations and decreased bacterial cell clumping were observed under scanning electron microscopy, and significantly decreased cell survival was noted using fluorescence microscopy. Together, these results suggest that terpinen-4-ol is a potential antibacterial agent with bactericidal properties, and can also act on established biofilms.

Actin alpha 2, smooth muscle, a transforming growth factor-β1-induced factor, regulates collagen production in human periodontal ligament cells via Smad2/3 pathway

Background/purpose

Actin alpha 2, smooth muscle (ACTA2) is an actin isoform that forms the cytoskeleton. Actin plays a crucial role in numerous cellular functions. ACTA2 is a marker of functional periodontal ligament (PDL) fibroblasts and is upregulated by transforming growth factor-β1 (TGF-β1); however, the underlying function of ACTA2 in PDL tissue is unknown. We aimed to examine the localization and potential function of ACTA2 in PDL tissues and cells.

Materials and methods

RNA expression was determined using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Protein expression was determined using immunofluorescence staining and Western blot analysis. Soluble and insoluble collagen production was examined using the Sircol collagen assay and picrosirius red staining, respectively. Small interfering RNA (siRNA) was used for knockdown assay to examine the effect of ACTA2 in human PDL cells.

Results

ACTA2 expression was observed in human primary PDL cells and PDL cell line (2-23 cells). TGF-β1 upregulated ACTA2, collagen type Ⅰ alpha1 chain (COL1A1), periostin (POSTN), and fibrillin-Ⅰ(FBN1) expression and soluble and insoluble collagen production in 2-23 cells. However, ACTA2 depletion by siRNA strongly suppressed PDL-related gene expression and collagen production compared with those of TGF-β1-stimulated control cells. Furthermore, ACTA2 knockdown significantly suppressed the phosphorylation of Smad2 and Smad3.

Conclusion

ACTA2 plays a crucial role in PDL-related marker expression and collagen production via Smad2/3 phosphorylation. Our findings might contribute to the development of novel and effective periodontal therapies.

Functions of beta2-adrenergic receptor in human periodontal ligament cells

Adrenergic receptors (ARs) are receptors of noradrenalin and adrenalin, of which there are nine different subtypes. In particular, β2 adrenergic receptor (β2-AR) is known to be related to the restoration and maintenance of homeostasis in bone and cardiac tissues; however, the functional role of signaling through β2-AR in periodontal ligament (PDL) tissue has not been fully examined. In this report, we investigated that β2-AR expression in PDL tissues and their features in PDL cells. β2-AR expressed in rat PDL tissues and human PDL cells (HPDLCs) derived from two different patients (HPDLCs-2G and -3S). Rat PDL tissue with occlusal loading showed high β2-AR expression, while its expression was downregulated in that without loading. In HPDLCs, β2-AR expression was increased exposed to stretch loading. The gene expression of PDL-related molecules was investigated in PDL clone cells (2-23 cells) overexpressing β2-AR. Their gene expression and intracellular cyclic adenosine monophosphate (cAMP) levels were also investigated in HPDLCs treated with a specific β2-AR agonist, fenoterol (FEN). Overexpression of β2-AR significantly promoted the gene expression of PDL-related molecules in 2 to 23 cells. FEN led to an upregulation in the expression of PDL-related molecules and increased intracellular cAMP levels in HPDLCs. In both HPDLCs, inhibition of cAMP signaling by using protein kinase A inhibitor suppressed the FEN-induced gene expression of α-smooth muscle actin. Our findings suggest that the occlusal force is important for β2-AR expression in PDL tissue and β2-AR is involved in fibroblastic differentiation and collagen synthesis of PDL cells. The signaling through β2-AR might be important for restoration and homeostasis of PDL tissue.

Novel proteins that regulate cell extension formation in fibroblasts

Cell extensions are critical structures that enable matrix remodeling in wound healing and cancer invasion but the regulation of their formation is not well-defined. We searched for new proteins that mediated cell extension formation over collagen by tandem mass tagged mass spectrometry analysis of purified extensions in 3T3 fibroblasts. Unexpectedly, importin-5, ENH isoform 1b (PDLIM5) and 26 S protease regulatory subunit 6B (PSMC4) were more abundant (> 10-fold) in membrane-penetrating cell extensions than cell bodies, which was confirmed by immunostaining and immunoblotting and also observed in human gingival fibroblasts. After siRNA knockdown of these proteins and plating cells on grid-supported floating collagen gels for 6 h, formation of cell extensions and collagen remodeling were examined. Knockdown of importin-5 reduced collagen compaction (1.9-fold), pericellular collagen degradation (~ 1.8-fold) and number of cell extensions (~ 69%). Knockdown of PSMC4 reduced collagen compaction (~ 1.5-fold), pericellular collagen degradation (~ 1.7-fold) and number of cell extensions (~ 42%). Knockdown of PDLIM5 reduced collagen compaction (~ 1.6-fold) and number of cell extensions (~ 21%). Inhibition of the TGF-β RI kinase, Smad3 or ROCK-II signaling pathways reduced the abundance of PDLIM5 in cell extensions but PSMC4 and importin-5 were reduced only by Smad3 or ROCK-II inhibitors. We conclude that these novel proteins are required for cell extension formation and their recruitment into extensions involves the Smad3 and ROCK signaling pathways.

A Screening System for Evaluating Cell Extension Formation, Collagen Compaction, and Degradation in Drug Discovery

The generation of cell extensions is critical for matrix remodeling in tissue invasion by cancer cells, but current methods for identifying molecules that regulate cell extension formation and matrix remodeling are not well adapted for screening purposes. We applied a grid-supported, floating collagen gel system (~100 Pa stiffness) to examine cell extension formation, collagen compaction, and collagen degradation in a single assay. With the use of cultured diploid fibroblasts, a fibroblast cell line, and two cancer cell lines, we found that compared with attached collagen gels (~2800 Pa), the mean number and length of cell extensions were respectively greater in the floating gels. In assessing specific processes in cell extension formation, compared with controls, the number of cell extensions was reduced by latrunculin B, β1 integrin blockade, and a formin FH2 domain inhibitor. Screening of a kinase inhibitor library (480 compounds) with the floating gel assay showed that compared with vehicle-treated cells, there were large reductions of collagen compaction, pericellular collagen degradation, and number of cell extensions after treatment with SB431542, SIS3, Fasudil, GSK650394, and PKC-412. These data indicate that the grid-supported floating collagen gel model can be used to screen for inhibitors of cell extension formation and critical matrix remodeling events associated with cancer cell invasion.

Calcium-sensing receptor-ERK signaling promotes odontoblastic differentiation of human dental pulp cells

Activation of the G protein-coupled calcium-sensing receptor (CaSR) has crucial roles in skeletal development and bone turnover. Our recent study has identified a role for activated CaSR in the osteogenic differentiation of human periodontal ligament stem cells. Furthermore, odontoblasts residing inside the tooth pulp chamber play a central role in dentin formation. However, it remains unclear how CaSR activation affects the odontoblastic differentiation of human dental pulp cells (HDPCs). We have investigated the odontoblastic differentiation of HDPCs exposed to elevated levels of extracellular calcium (Ca) and strontium (Sr), and the contribution of CaSR and the L-type voltage-dependent calcium channel (L-VDCC) to this process. Immunochemical staining of rat dental pulp tissue demonstrated that CaSR was expressed at high levels in the odontoblastic layer, moderate levels in the sublayer, and low levels in the central pulp tissue. Although normal HDPCs expressed low levels of CaSR, stimulation with Ca or Sr promoted both CaSR expression and odontoblastic differentiation of HDPCs along with increased expression of odontoblastic makers. These effects were inhibited by treatment with a CaSR antagonist, whereas treatment with an L-VDCC inhibitor had no effect. Additionally, knockdown of CaSR with siRNA suppressed odontoblastic differentiation of Ca- and Sr-treated HDPCs. ERK1/2 phosphorylation was observed in Ca- and Sr-treated HDPCs, whereas CaSR antagonist treatment or CaSR knockdown blocked ERK1/2 phosphorylation. Furthermore, inhibition of ERK1/2 suppressed mineralization of Ca- and Sr-treated HDPCs. These results suggest that elevated concentrations of extracellular Ca and Sr induce odontoblastic differentiation of HDPCs through CaSR activation and the ERK1/2 phosphorylation.

GDNF From Human Periodontal Ligament Cells Treated With Pro-Inflammatory Cytokines Promotes Neurocytic Differentiation of PC12 Cells

Glial cell line-derived neurotrophic factor (GDNF) is known to mediate multiple biological activities such as promotion of cell motility and proliferation, and morphogenesis. However, little is known about its effects on periodontal ligament (PDL) cells. Recently, we reported that GDNF expression is increased in wounded rat PDL tissue and human PDL cells (HPDLCs) treated with pro-inflammatory cytokines. Here, we investigated the associated expression of GDNF and the pro-inflammatory cytokine interleukin-1 beta (IL-1β) in wounded PDL tissue, and whether HPDLCs secrete GDNF which affects neurocytic differentiation. Rat PDL cells near the wounded area showed intense immunoreactions against an anti-GDNF antibody, where immunoreactivity was also increased against an anti-IL-1β antibody. Compared with untreated cells, HPDLCs treated with IL-1β or tumor necrosis factor-alpha showed an increase in the secretion of GDNF protein. Conditioned medium of IL-1β-treated HPDLCs (IL-1β-CM) increased neurite outgrowth of PC12 rat adrenal pheochromocytoma cells. The expression levels of two neural regeneration-associated genes, growth-associated protein-43 (Gap-43), and small proline-rich repeat protein 1A (Sprr1A), were also upregulated in IL-1β-CM-treated PC12 cells. These stimulatory effects of IL-1β-CM were significantly inhibited by a neutralizing antibody against GDNF. In addition, U0126, a MEK inhibitor, inhibited GDNF-induced neurite outgrowth of PC12 cells. These findings suggest that an increase of GDNF in wounded PDL tissue might play an important role in neural regeneration probably via the MEK/ERK signaling pathway. J. Cell. Biochem. 118: 699-708, 2017. © 2016 Wiley Periodicals, Inc.

Benzo[a]pyrene/aryl hydrocarbon receptor signaling inhibits osteoblastic differentiation and collagen synthesis of human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Cigarette smoking has detrimental effects on periodontal tissue, and is known to be a risk factor for periodontal disease, including the loss of alveolar bone and ligament tissue. However, the direct effects of cigarette smoking on periodontal tissue remain unclear. Recently, we demonstrated that benzo[a]pyrene (BaP), which is a prototypic member of polycyclic aryl hydrocarbons and forms part of the content of cigarettes, attenuated the expression of extracellular matrix remodeling-related genes in human periodontal ligament (PDL) cells (HPDLCs). Thus, we aimed to examine the effects of BaP on the osteoblastic differentiation and collagen synthesis of HPDLCs.

MATERIAL AND METHODS

HPDLCs were obtained from healthy molars of three patients, and quantitative reverse transcription-polymerase chain reaction were performed for gene expression analyses of cytochrome P450 1A1 and 1B1, alkaline phosphatase, bone sialoprotein and aryl hydrocarbon receptor (AhR), a receptor for polycyclic aryl hydrocarbons. We have also analyzed the role of the AhR, using 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH-223191), which is an AhR antagonist.

RESULTS

The treatment of HPDLCs with BaP reduced mRNA expression of osteogenic genes, alkaline phosphatase activity, mineralization and collagen synthesis. The treatment with CH-223191 subsequently restored the observed suppressive effects of BaP on HPDLCs.

CONCLUSIONS

The present results suggest that BaP exerts inhibitory effects on the maintenance of homeostasis in HPDL tissue, such as osteoblastic differentiation and collagen synthesis of HPDLCs, and that this signaling pathway could be suppressed by preventing the transactivity of AhR. Future studies may unveil a role for the inhibition of AhR as a promising therapeutic agent for periodontal disease caused by cigarette smoking.

Effects of Activin A on the phenotypic properties of human periodontal ligament cells

Periodontal ligament (PDL) tissue plays an important role in tooth preservation by structurally maintaining the connection between the tooth root and the bone. The mechanisms involved in the healing and regeneration of damaged PDL tissue, caused by bacterial infection, caries and trauma, have been explored. Accumulating evidence suggests that Activin A, a member of the transforming growth factor-β (TGF-β) superfamily and a dimer of inhibinβa, contributes to tissue healing through cell proliferation, migration, and differentiation of various target cells. In bone, Activin A has been shown to exert an inhibitory effect on osteoblast maturation and mineralization. However, there have been no reports examining the expression and function of Activin A in human PDL cells (HPDLCs). Thus, we aimed to investigate the biological effects of Activin A on HPDLCs. Activin A was observed to be localized in HPDLCs and rat PDL tissue. When PDL tissue was surgically damaged, Activin A and IL-1β expression increased and the two proteins were shown to be co-localized around the lesion. HPDLCs treated with IL-1β or TNF-α also up-regulated the expression of the gene encoding inhibinβa. Activin A promoted chemotaxis, migration and proliferation of HPDLCs, and caused an increase in fibroblastic differentiation of these cells while down-regulating their osteoblastic differentiation. These osteoblastic inhibitory effects of Activin A, however, were only noted during the early phase of HPDLC osteoblastic differentiation, with later exposures having no effect on differentiation. Collectively, our results suggest that Activin A could be used as a therapeutic agent for healing and regenerating PDL tissue in response to disease, trauma or surgical reconstruction.

Expression and effects of epidermal growth factor on human periodontal ligament cells

Repair of damaged periodontal ligament (PDL) tissue is an essential challenge in tooth preservation. Various researchers have attempted to develop efficient therapies for healing and regenerating PDL tissue based on tissue engineering methods focused on targeting signaling molecules in PDL stem cells and other mesenchymal stem cells. In this context, we investigated the expression of epidermal growth factor (EGF) in normal and surgically wounded PDL tissues and its effect on chemotaxis and expression of osteoinductive and angiogenic factors in human PDL cells (HPDLCs). EGF as well as EGF receptor (EGFR) expression was observed in HPDLCs and entire PDL tissue. In a PDL tissue-injured model of rat, EGF and IL-1β were found to be upregulated in a perilesional pattern. Interleukin-1β induced EGF expression in HPDLCs but not EGFR. It also increased transforming growth factor-α (TGF-α) and heparin-binding EGF-like growth factor (HB-EGF) expression. Transwell assays demonstrated the chemotactic activity of EGF on HPDLCs. In addition, EGF treatment significantly induced secretion of bone morphogenetic protein 2 and vascular endothelial growth factor, and gene expression of interleukin-8 (IL-8), and early growth response-1 and -2 (EGR-1/2). Human umbilical vein endothelial cells developed well-formed tube networks when cultured with the supernatant of EGF-treated HPDLCs. These results indicated that EGF upregulated under inflammatory conditions plays roles in the repair of wounded PDL tissue, suggesting its function as a prospective agent to allow the healing and regeneration of this tissue.

[Successful treatment of ruptured descending thoracic aortic aneurysm associated with right tension hemothorax during operation]

A 59-year-old man was admitted to the hospital, suspected of the rupture of descending thoracic aortic aneurysm due to sudden back pain. Enhanced computed tomography revealed a ruptured descending thoracic aortic aneurysm with huge hematoma and abdominal aortic aneurysm. Based on the above diagnosis, we performed urgent operation through left thoracotomy under unilateral lung ventilation. While dissecting the aneurysm, sudden hemodynamics deterioration occurred. Although cardiopulmonary bypass was introduced immediately through femoral artery and femoral vein cannulations, hemodynamics was not improved and unilateral lung ventilation got more unmanageable. We diagnosed right tension hemothorax due to the extension of aneurysm rupture into the right thoracic cavity. After placing a cannula at the distal arch for a central perfusion, we clamped the descending thoracic aorta at both the proximal and distal sites of the aneurysm. Thereafter we opened the aneurysm and drained the right thorax through the aneursym's tear. The aneurysm was replaced with a prosthetic woven-Dacron vascular graft. The patient's postoperative condition had been stable with no significant unfavorable event. The abdominal aortic aneurysm was replaced with a bifurcated graft on 51st postoperative day. He was discharged in good condition on the 69th postoperative day.

[Successful surgical treatment of acute pulmonary thromboembolism caused by giant intra-pervic tumor; report of a case]

A 40-year-old woman was admitted to our hospital because of operation for giant intra-pervic tumor. She had a history of deep vein thrombosis. Suddenly she complained severe dyspnea while having a bath, and subsequently cardiogenic shock occurred. Immediately we set up percutaneous cardiopulmonary support (PCPS) for acute pulmonary thromboembolism. Despite thrombolytic therapy including the administration of urokinase and rt-PA, hemodinamics were not improved. Emergent pulmonary embolectomy was performed on-pump beating. Postoperative course was uneventful. The intra-pervic tumor was removed on the 24th postoperative day. She was discharged in good condition on the 38th postoperative day. Quick diagnosis and appropriate therapy are essential in patient with acute massive pulmonary thromboembolism.

[Use of a balloon occlusion catheter for descending aortic aneurysm after total arch replacement using the elephant trunk technique]

A 74-year-old man who had previously undergone prosthetic graft replacement of the total aortic arch using the elephant trunk technique and of the abdominal aorta was admitted to our hospital for surgical treatment of descending aortic aneurysm. Computed tomography (CT) on admission revealed descending aortic aneurysm of 6.5 cm in diameter, and the previously placed prosthetic graft was detected in the aneurysm. Surgery for the descending aorta was performed under femoro-femoral partial bypass. During the operation, a balloon occlusion catheter introduced through the right brachial artery into the 'elephant trunk' graft was inflated before the aneurysm was opened, then the previously placed prosthetic graft was cross-clamped and the descending aorta was replaced with a new prosthetic graft with usual fashion. The postoperative course was uneventful.

[Acute pulmonary embolism after cesarean section; report of a case]

We present a case of acute pulmonary embolism (APE) after cesarean section. A cesarean section was performed on a 27-year old woman with normal course. However, one day after operation, she suddenly developed syncope and dyspnea. Soon after the symptom, she developed hypotension 60 mmHg. As a result of various examinations, her illness was diagnosed as APE with right ventricular dysfunction after cesarean section. She was consulted to our hospital for treatment. Soon after her arrival, we treated her for both APE and cardiogenic shock. The combined with antithrombotic therapy using heparin sodium, was successfully treated the patient from cardiogenic shock due to APE with right ventricular dysfunction after cesarean section.

Significance of chymase-dependent angiotensin II-forming pathway in the development of vascular proliferation

BACKGROUND

Vascular tissues of humans and dogs contain chymase as an angiotensin II-forming enzyme. In this study, we investigated whether chymase-dependent angiotensin II formation plays a crucial role in the development of vascular proliferation in dog grafted veins.

METHODS AND RESULTS

The right external jugular vein of dogs was grafted to the ipsilateral carotid artery. As a control group, the right external jugular veins in dogs that had not received grafts were used. In the chymase inhibitor-treated group, the vein was infiltrated with 10 micromol/L Suc-Val-Pro-Phe(P)(OPh)(2) and was grafted to the carotid artery. In the placebo-treated group, ACE activity in the grafted veins was significantly lower than that in the control veins up to 7 days after the operation, whereas chymase activity was increased significantly. After 7 days, the mRNA levels of collagen I, collagen III, and fibronectin, all of which are induced by an increase of angiotensin II action, were significantly increased in the grafted veins, and the intima-media ratio of the grafted veins was also increased. In the chymase inhibitor-treated group, the chymase activity in the grafted veins 7 days after the operation was suppressed to 12.1%. The elevated mRNA levels of fibronectin, collagen I, and collagen III in the grafted veins were significantly suppressed by treatment with the chymase inhibitor, and the intima-media ratio was also decreased significantly.

CONCLUSIONS

We demonstrate for the first time that chymase-dependent angiotensin II formation plays an important role in the development of vascular proliferation in the grafted veins.

Oral administration of a specific chymase inhibitor, NK3201, inhibits vascular proliferation in grafted vein

Chymase may play an important role in vascular proliferation, as shown by in-vitro experiments, but the role of chymase in vivo has been unclear. In this study, we investigated the effect of a novel chymase inhibitor, NK3201, on this proliferation in dog grafted veins. NK3201 inhibited human and dog chymases, but not rabbit ACE. NK3201 suppressed the Ang I-induced vascular contraction in isolated dog arteries in the presence of an ACE inhibitor, and the IC50 value of chymostatin and NK3201 in dog artery was 320 nM. In dog, the concentration of NK3201 in blood was about 10 microM at 24 h after oral administration of the drug (5 mg/kg). In the group treated with NK3201, each dog was administered orally 5 mg/kg per day from 5 days before to the day before the removal of the grafted veins. Each dog underwent right common carotid artery bypass grafting with the ipsilaterial external jugular vein. By 28 days after grafting, a significant vascular proliferation was observed in the grafted veins and the chymase activity was also increased significantly. Treatment with chymase inhibitor significantly suppressed the proliferation of the grafted veins and the increased chymase activity. In this study, we demonstrate for the first time that oral administration of a specific chymase inhibitor, NK3201, appears useful for preventing vascular proliferation.

Chymase-dependent angiotensin II formation in the saphenous vein versus the internal thoracic artery

OBJECTIVES

The great saphenous vein graft is known to be less patent than the internal thoracic artery graft. Recently, we reported that chymase-dependent angiotensin II formation plays an important role in the development of intimal hyperplasia in dog grafted veins. In this study we investigated the levels of angiotensin II-forming enzymes, angiotensin-converting enzyme, and chymase in human saphenous veins and internal thoracic arteries.

METHODS

The saphenous vein and internal thoracic artery specimens were obtained from coronary artery bypass grafts of patients during surgical procedures (saphenous vein, n = 16; internal thoracic artery, n = 16). Activities of angiotensin-converting enzyme and chymase were determined by using the extract from the saphenous vein or internal thoracic artery. Sections of the saphenous vein or internal thoracic artery were stained with van Gieson's elastin stain and were immunostained with anti-human chymase antibody.

RESULTS

The activities of angiotensin-converting enzyme in the saphenous vein and internal thoracic artery were 0.34 +/- 0.12 and 0.32 +/- 0.17 mU/mg protein, respectively, and the difference was not significant. The chymase activity in the saphenous vein was significantly higher than that in the internal thoracic artery (saphenous vein, 10.1 +/- 0.81 mU/mg protein; internal thoracic artery, 6.21 +/- 1.86 mU/mg protein). Chymase-positive cells in the saphenous vein were located in both the media and adventitia, and those in the internal thoracic artery were located only in the adventitia. The number of chymase-positive cells in the saphenous vein was about 2.6 times that in the internal thoracic artery.

CONCLUSION

The chymase activity, but not the angiotensin-converting enzyme activity, was significantly higher in the saphenous vein, suggesting that the high levels of chymase activity may be related to the poorer performance of the saphenous vein for use as a bypass conduit.

Cilostazol suppresses intimal formation in dog grafted veins with reduction of angiotensin II-forming enzymes

Cilostazol prevents neointimal formation, but its mechanism has remained unclear. We investigated whether intimal formation in dog grafted veins is suppressed by cilostazol, and studied the effect of cilostazol on angiotensin II-forming enzymes. The external jugular vein was grafted to the carotid artery, and cilostazol (60 mg/kg/day) was administered orally. By 28 days after the surgery, the intimal cross-sectional area of the grafted vein was reduced to 16.7% by treatment of cilostazol, and the activities of angiotensin II-forming enzymes were suppressed significantly. The inhibitory effect of cilostazol in intimal formation may be dependent on inhibition of angiotensin II-forming enzymes.

Angiotensin II receptor antagonist, L-158,809, prevents intimal hyperplasia in dog grafted veins

We investigated the levels of the angiotensin II-forming enzymes, chymase and angiotensin converting enzyme (ACE), in dog grafted veins, and studied the effect of an angiotensin II type 1 receptor antagonist, L-158,809, on vascular proliferation in the grafted veins. The right external jugular vein was grafted to the ipsilaterial carotid artery. In the group treated with L-158,809, the drug (10 mg/kg per day, p.o.) were administered orally from 7 days before the operation to 28 days after it, while the others were administrated placebo. In the placebo-treated group, the chymase activity in the grafted veins was increased about 10-fold and the ACE activity was doubled. The areas of intima and media were significantly increased in the grafted veins in the placebo-treated group. L-158,809 significantly reduced the intimal area of the grafted veins. An angiotensin II receptor antagonist, L-158,809, prevented the vascular proliferation in the grafted veins, and the development of the proliferation may depend on activation of local angiotensin II formation.

Inhibition of chymase reduces vascular proliferation in dog grafted veins

We investigated the effect of a chymase inhibitor Suc-Val-Pro-Phe(P)(OPh)(2) on the proliferation of the grafted vein in dog. By 28 days after the operation, the mean intimal area of the grafted vein in the placebo group was 3.24+/-0.32 mm(2). The intimal area of the grafted vein in the chymase inhibitor-treated group was reduced to 63.9%. In the placebo group, the activities of chymase and angiotensin-converting enzyme in grafted vein were significantly increased 15- and 2-fold, respectively. In the chymase inhibitor-treated group, chymase activity in the grafted veins was decreased significantly. These findings suggest that inhibition of chymase appears useful for preventing vascular proliferation.

[A case report of infective endocarditis caused by MRSA and characterized by pedicled vegetation on the posterior wall of left atrium]

We report here a case of active infective endocarditis caused by Methicilin-Resistant Staphylococcus aureus (MRSA). A 24-year-old woman was admitted to the Osaka Medical Collage Hospital with continuous fever. After admission, MRSA was detected by blood culture and chemotherapy with Vancomycin was started. However, after 1 week, her condition had not improved. Moreover, a pedicled vegetation on the posterior wall of the left atrium and mitral regurgitation due to prolapse of the anterior leaflet were revealed by transesophageal echocardiography. The vegetation grew to about 2 cm in diameter and prolapsed into the left ventricle during diastole. We performed an early operation although the infection was still active due to its rapid growth and the risk of embolism. There was a large pedicled vegetation on the posterior wall of the left atrium as shown by preoperative echocardiography, but the mitral valve appeared to be intact. Therefore, the vegetation was completely removed and the mitral annulus was plicated by Kay's method to treat the associated mitral regurgitation. Postoperatively, we administered VCM 2 g/day for 24 days. The course was uneventful. The patient was discharged from the hospital on the 31st postoperative day.

[A case report of coronary artery bypass grafting in a patient with ankylosing spondylitis]

We reported a case of ankylosing spondylitis who successfully underwent coronary artery bypass grafting (CABG) for unstable angina pectoris. A 67-year-old man was admitted with symptom of anginal pain. Selective coronary angiography revealed coronary artery stenoses; 90% in seg 6, 90% in seg 11, proximal 75%, distal 90% in seg 3, 99% in 4 PD and 99% with delay in 4 AV. The left internal thoracic artery was anastomosed to seg 7 and saphenous vein (SVG) to PL-2, PL-1 sequentially, and another SVG to 4 PD. His postoperative course was uneventful. Cardiac lesions accompanied by ankylosing spondylitis are rare in Japan. Perioperative problems of these lesions therefore, are discussed.

[Rupture of thoracic aorta due to blunt trauma: a report of three cases]

Three cases of the thoracic aortic rupture due to blunt trauma were successfully treated. All of the cases were young male motorcyclists. The chest X-ray on admission showed either a widened mediastinum or an apical extrapleural cap sign. Ruptures were confirmed by an enhanced CT clearly showing the presence of a psuedoaneurysm and a hematoma around the isthmus of the aorta. One of them was operated upon urgently and others in whom heparin could not be used because of associated injuries were operated upon electively two and three months after the traffic accident, respectively. In two of them, aneurysms were removed and replaced with dacron grafts and in the remaining one, the aneurysm was resected and repaired directly under the femoro-femoral bypass. Post-operative courses were uneventful. They discharged and are doing well after the treatment for associated injuries. In view of the high early mortality of aortic rupture, an early diagnosis and treatment is important. But in the case who has stable hemodynamics and contraindication for heparinization, a delayed operation may be recommended.