[Mitral regurgitation due to sole punched out lesion of the mitral anterior leaflet in infective endocarditis; report of a case]

Mitral regurgitation (MR) due to only punched out lesion is extremely rare in infective endocarditis. A 31-year-old male was admitted to our hospital due to unusual cause of MR. Echocardiography showed MR due to punched out lesion of the mitral anterior leaflet, which is extremely rare. A round shape punched out lesion (about 16 mm in size) was found intraoperatively in the anterior leaflet of the mitral valve. The surface around the punched out lesion was smooth, and the leaflet displayed good movability. Neither vegetation nor calcification was found. Punched out lesion was successfully closed with autologous pericardial patch and annuloplasty was performed.

Low grade malignant peripheral nerve sheath tumour: varied cytological and histological patterns

BACKGROUND

A small number of malignant peripheral nerve sheath tumours (MPNSTs) are low grade, and the nature of these low grade tumours has never been systematically assessed.

AIMS

To describe the clinicopathological, immunohistochemical, and ultrastructural features of low grade MPNST and to discuss the main differential diagnoses.

METHODS

Four cases of low grade MPNST were studied, including one coexistent with neurofibromatosis type 1. The tumours were analysed with respect to nuclear atypia, cellularity, nuclear enlargement, hyperchromasia, mitotic rate, and necrosis. Immunohistochemistry was performed by standard techniques, and an ultrastructural study was performed on one tumour.

RESULTS

The ages of the patients ranged from 32 to 72 years (mean, 58). Two were male and two were female. Three tumours occurred in the deep tissue, including one in the retroperitoneum, and one was located in the dermal and subcutaneous tissue. The maximum diameters of the tumours ranged from 3.5 to 8.0 cm. Microscopically, all tumours showed moderate hypercellularity, an increased nuclear to cytoplasmic ratio, and hyperchromasia, but exhibited varied growth patterns, including those that were atypical neurofibroma-like, low grade fibromyxoid sarcoma-like, low grade epithelioid, and haemangiopericytoma-like. All tumours showed immunoreactivity for S-100 protein and vimentin.

CONCLUSIONS

These findings suggest that careful clinical and histological evaluation, along with S-100 protein immunostaining, are essential for the accurate diagnosis of low grade MPNST.

Tyr-317 phosphorylation increases Shc structural rigidity and reduces coupling of domain motions remote from the phosphorylation site as revealed by molecular dynamics simulations

Activated receptor tyrosine kinases bind the Shc adaptor protein through its N-terminal phosphotyrosine-binding (PTB) and C-terminal Src homology 2 (SH2) domains. After binding, Shc is phosphorylated within the central collagen-homology (CH) linker region on Tyr-317, a residue remote to both the PTB and SH2 domains. Shc phosphorylation plays a pivotal role in the initiation of mitogenic signaling through the Ras/Raf/MEK/ERK pathway, but it is unclear if Tyr-317 phosphorylation affects Shc-receptor interactions through the PTB and SH2 domains. To investigate the structural impact of Shc phosphorylation, molecular dynamics simulations were carried out using special-purpose Molecular Dynamics Machine-Grape computers. After a 1-nanosecond equilibration, atomic motions in the structures of unphosphorylated Shc and Shc phosphorylated on Tyr-317 were calculated during a 2-nanosecond period. The results reveal larger phosphotyrosine-binding domain fluctuations and more structural flexibility of unphosphorylated Shc compared with phosphorylated Shc. Collective motions between the PTB-SH2, PTB-CH, and CH-SH2 domains were highly correlated only in unphosphorylated Shc. Dramatic changes in domain coupling and structural rigidity, induced by Tyr-317 phosphorylation, may alter Shc function, bringing about marked differences in the association of unphosphorylated and phosphorylated Shc with its numerous partners, including activated membrane receptors.

Prognostic significance of grading (MIB-1 system) in patients with myxoid liposarcoma

AIMS

To determine the relation between clinical outcome and tumour grade defined by a MIB-1 (Ki-67) score based grading system.

METHOD

The clinical and pathological features of 50 patients with myxoid liposarcoma were evaluated, and MIB-1 immunostaining was performed to grade these patients' tumours. Univariate and multivariate analyses were conducted to evaluate survival. Clinical follow up details were available for all patients (median, 46.5 months; range, 9-408).

RESULTS

Univariate analysis revealed that the tumour site (p < 0.05), round cell component content (p < 0.01), necrosis (p < 0.01), mitosis (p < 0.01), MIB-1 labelling index (p < 0.001), and tumour grade (p < 0.001) had a significant impact on overall survival. Multivariate analysis showed that, of the variables evaluated, the tumour grade defined by a MIB-1 score based grading system was the most significant adverse prognostic factor.

CONCLUSION

Tumour grade determined by the grading system using the MIB-1 score (MIB-1 system) is a very strong prognostic factor in patients with myxoid liposarcoma.

[Total arch replacement for right aortic arch with Kommerell diverticulum and aberrant left subclavian artery]

A 57-year-old man suspected of having angina pectoris underwent coronary angiography and comprehensive examination, which revealed a right-side aortic arch accompanying Kommerell diverticulum and a aberrant left subclavian artery. Esophagography indicated that the esophagus was compressed on its right posterior side and the computed tomography (CT) revealed that the posterior side of the tracheal was compressed, however, the patient experienced no difficulty in breathing, hoarseness of voice or dysphasia. The size of the aortic diverticulum was less than 5 cm and the patient showed no symptom, however, if it was left untreated, there was a risk of rupture in the future. Also the esophagus and tracheal may develop complications due to prolonged compression. Therefore, we decided that the case required surgical operation. Total arch replacement was performed through mediastinotomy and right posterolateral in the 4th intercostal. The postoperative condition was good, and the patient was discharged without any complications.

[Early and mid-term results of all arterial graft coronary artery bypass grafting using bilateral internal thoracic and radial arterial conduits]

From March 1996 to May 2000, 41 patients [age 39-78 (mean 63.5 +/- 8.8) years, 90.2% male] underwent all arterial multiple coronary artery bypass grafting (CABG) using bilateral internal thoracic (BiITA) and radial (RA) arterial conduits. The reason for using RA was that the right gastroepiploic artery (RGEA) was small or occluded on preoperative angiography, a history of upper abdominal surgery or disease, or the right coronary arterial lesion was proximal and mild. The BiITA were used as in situ grafts and the proximal anastomosis of RA was to the ascending aorta in all cases. All patients underwent conventional elective CABG with median sternotomy using cardiopulmonary bypass. The mean number of anastomoses was 3.3 +/- 0.5 branches and complete revascularization rate was 80.5%. Postoperative follow-up averaged 20 months and the longest was 50 months. There was no early death, and overall graft patency 2-3 weeks after surgery was 96.2% (LITA 94.0%, RITA 97.6%, RA 97.6%). Four-year actuarial survival rate was 96.4 +/- 3.5% (1 patient: 9 months, no cardiac death), and cardiac event-free rate after surgery was 89.7 +/- 4.9% [4 patients: percutaneous transluminal coronary angioplasty (PTCA)]. However, once patients were discharged from hospital, cardiac event-free rate was 100%. These excellent results suggest that all arterial graft CABG was satisfactory, and RA can be used as a third suitable arterial bypass conduit, if RGEA cannot be used or is unsuitable for use.

Expression of connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24 (CTGF/Hcs24) during fracture healing

Localization and expression of connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24 (CTGF/Hcs24) during fracture healing in mouse ribs were investigated. In situ hybridization demonstrated that CTGF/Hcs24 mRNA was remarkably expressed, especially in hypertrophic chondrocytes and proliferating chondrocytes, in the regions of regenerating cartilage on days 8 and 14 after fracture. CTGF/Hcs24 mRNA was also expressed in proliferating periosteal cells in the vicinity of the fracture sites on days 2 and 8, and in cells in fibrous tissue around the callus on day 8. Northern blot analysis showed that expression of CTGF/Hcs24 mRNA was 3.9 times higher on day 2 of fracture healing than that on day 0. On day 8, it reached a peak of 8.6 times higher than that on day 0. It then declined to a lower level. Immunostaining showed that CTGF/Hcs24 was localized in hypertrophic chondrocytes and proliferating chondrocytes in the regions of regenerating cartilage, and in active osteoblasts in the regions of intramembranous ossification. Although CTGF/Hcs24 was abundant in the proliferating and differentiating cells (on days 8 and 14), immunostaining decreased as the cells differentiated to form bone (on day 20). CTGF/Hcs24 was also detected in cells in fibrous tissue, vascular endothelial cells in the callus, and periosteal cells around the fracture sites. These results suggest that CTGF/Hcs24 plays some role in fracture healing.

Population-based genetic alterations in Ewing's tumors from Japanese and European Caucasian patients

BACKGROUND

The incidence of Ewing's tumors (ETs) is lower in Asians or African-Americans than in Caucasians.

PATIENTS AND METHODS

Japanese ETs were available for analysis of chromosomal aberrations by comparative genomic hybridization (n = 16) and for expression of chimeric EWS transcripts by reverse-transcriptase polymerase chain reaction (n = 11). These results in Japanese patients were compared with those of 62 ETs in European Caucasian patients registered in the European Intergroup Cooperative Ewing's Sarcoma Study.

RESULTS

Japanese patients with ET had lower overall survival (P = 0.0446) and relapse-free survival (P = 0.0371) compared with European Caucasian patients. Ten of 11 Japanese ETs and 31 of 62 European Caucasian ETs had type I (EWS exon 7 to FLI1 exon 6) fusion transcripts. In Japanese ETs, the median numbers of chromosomal aberrations were 2.0 and 6.0 in 11 primary tumors and five relapsed tumors, respectively. In European Caucasian ETs, the median number of changes were 2.5 and 5.0 in 52 primary and 10 relapsed tumors, respectively. Frequent gains were 8q (38%), 8p (31%) and 12q (25%) in Japanese ETs and 8q (52%), 8p (48%) and 12q (19%) in European Caucasian ETs. Frequent losses were 19q (44%), 19p (38%) and 17p (25%) in Japanese ETs and 16q (21%), 19q (18%) and 17p (15%) in European Caucasian ETs. The incidence of losses of 19p (P = 0.0215) and 19q (P = 0.0277) were significantly higher in Japanese ETs than in European Caucasian ETs. An amplification (1p33-p34) was observed in only one Japanese ET.

CONCLUSIONS

Japanese patients with ET in this study had a worse prognosis than European Caucasian patients. In molecular genetic analyses, Japanese ETs had a higher frequency of loss of chromosome 19 than European Caucasian ETs. Different genetic aberrations may explain the different incidences and prognoses of ET between Caucasian and Japanese patients.

Effects of mutation in hepatitis C virus nonstructural protein 5A on interferon resistance mediated by inhibition of PKR kinase activity in mammalian cells

The IFN-induced double-stranded RNA (dsRNA)-activated protein kinase PKR is one of the key molecules in the antiviral effects of IFN. To clarify the effects of hepatitis C virus nonstructural protein 5A (NS5A) on antiviral activity of IFN, in particular on PKR kinase activity, in mammalian cells, we established inducible NS5A-expressing cell lines derived from human osteosarcoma (Saos-2). The cells expressing NS5A derived from an IFN-resistant clone (NS5A-lb) that interacted with endogenous PKR in vitro, showed a suppressive effect on IFN function as determined by interference with vesicular stomatitis virus (VSV) infection, whereas NS5A (NS5A-2a) from an IFN-sensitive clone did not block the antiviral effect of IFN. A mutant with deletion of the IFN sensitivity determining region (ISDR) in NS5A-1b (NS5A-AISDR) also interacted with PKR and suppressed its activity in vitro. However, neither NS5A-2a nor the C-terminal truncated mutant of NS5A-1b (NS5A-deltaC) blocked PKR activity. These observations confirmed the previous report that the inhibitory effect of NS5A on IFN activity is mediated at least in part by the repression of PKR. In addition, we showed that IFN sensitivity was determined not only by the ISDR but that the involvement of the C-terminal region of NS5A-1b is important for the suppression of PKR activity.

Inhibition of human chondrosarcoma cell growth via apoptosis by peroxisome proliferator-activated receptor-gamma

A rare immunohistochemical study using 28 surgical sections of human chondrosarcoma revealed that 67.9% of tumour cells had weak (10-40%) or strong (>40%) positive immunoreaction for peroxisome proliferator-activated receptor-gamma. The expression of peroxisome proliferator-activated receptor-gamma mRNA and protein in human chondrosarcoma cell line OUMS-27 was also determined by reverse transcription-polymerase chain reaction and immunocytochemistry, respectively. Furthermore, the effects of peroxisome proliferator-activated receptor-gamma ligands on cell proliferation and survival were investigated in OUMS-27 cells. Pioglitazone, a selective ligand for peroxisome proliferator-activated receptor-gamma, and 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), a putative endogenous ligand for peroxisome proliferator-activated receptor-gamma, inhibited the proliferation of OUMS-27 cells in a dose-dependent manner. The mechanism of cytotoxic effects of 15d-PGJ(2) was via apoptosis as shown by DNA fragmentation using TUNEL stain and DNA ladder formation, and by ultrastructural analysis using transmission electron microscopy. Flow-cytometric analysis using annexin-V-fluorescein and propidium iodide detected the early change of apoptosis, as well as necrosis of OUMS-27 cells at 4 h after co-incubation with 15d-PGJ(2). These results suggest that peroxisome proliferator-activated receptor-gamma may play a significant role in the pathogenesis of chondrosarcoma, and peroxisome proliferator-activated receptor-gamma ligands, especially 15d-PGJ(2), may be of therapeutic value in the treatment of human chondrosarcoma.

[Dissecting aneurysm of ventricular septum following acute inferior myocardial infarction]

Dissecting aneurysm of the ventricular septum as a complication after myocardial infarction (MI) is very rare. The patient was a 70-year-old women who was diagnosed with acute inferior MI. Three months after MI, catheterization showed a left ventricular aneurysm of the inferior wall, and left-to-right ventricular shunt flow was detected in the aneurysm. Echocardiography showed that the inferior left ventricular free wall was aneurysmal and dissected from the septal wall. Nine months after MI, chronic heart failure was uncontrollable by medication. At surgery, a tear (5 mm long) in the dissecting aneurysm of the ventricular septum was found and closed directly using 2 felt patches, and aneurysmectomy was performed using felt strips. The postoperative course was uneventful and she has been free from any complication for over 1 year.

Diagnosis of infection after total hip arthroplasty

Forty-eight total hip arthroplasties for which revision surgery was performed were reviewed to determine the accuracy of laboratory tests, plain radiographs, hip aspiration, and technetium-99m MDP and gallium-67 scans in demonstrating the presence or absence of infection of the prosthesis. Six of the 48 hips were diagnosed as having an infection at the revision surgery. The erythrocyte sedimentation rate and the C-reactive protein levels were significantly higher in the patients with infected prostheses. The difference in the white blood cell count was not significant. There was no significant relationship between the presence of infection and the severity of loosening and instability of the implants diagnosed by plain radiographs. The accuracy of hip aspiration in diagnosing the infection was 83%, with a sensitivity of 40% and a specificity of 92%. The accuracy of technetium-99m MDP bone scan was 79%, with a sensitivity of 83%, and a specificity of 79%. Gallium-67 scan had an accuracy of 96%, a sensitivity of 67%, and a specificity of 100%. The findings in the present study indicated that diagnostic tests consisting of laboratory tests and plain radiography, followed by hip aspiration and sequential use of technetium-99m MDP and gallium-67 scintigraphies, are suitable for differentiation between mechanical loosening and infection of total hip arthroplasty.

Dynamic magnetic resonance imaging of femoral head perfusion in femoral neck fracture

A prospective followup study of 36 femoral neck fractures according to the assessment of femoral head perfusion using dynamic magnetic resonance imaging is reported. Patients were divided into three groups based on the dynamic magnetic resonance imaging findings (dynamic curve pattern and relative enhancement ratio) that were conducted within 48 hours of the injury. Traction was used to achieve anatomic reduction and to prevent additional damage to vascularity until minimally invasive internal fixation could be done. The fractures of all 17 patients whose femoral head perfusion was normal (Type A; n = 11) or was impaired but not totally absent (Type B; n = 6) healed without complications. Among the 19 patients whose femoral head perfusion was absent (Type C), 15 had complications (osteonecrosis, n = 10; nonunion, n = 5). Assuming that fractures with a Type A or Type B curve pattern would unite successfully and that those with a Type C curve pattern would not, the sensitivity, specificity, and accuracy of the predictions of successful osteosynthesis of the femoral neck fractures using this method were 81%, 100%, and 89%, respectively. The current classification of femoral neck fractures using dynamic magnetic resonance imaging may be useful in selecting an appropriate treatment method for the fractures.

[Cardiovascular effects of colforsin daropate hydrochloride for acute heart failure after open heart surgery]

Colforsin daropate hydrochloride (COL) is a novel drug for the treatment of acute heart failure. COL stimulates adenylate cyclase directly and produces positive inotropic and vasodilator effects accompanied by the increase in cellular cAMP. We investigated its cardiovascular effects for 9 patients who showed low cardiac index (< 3.0 l/min/m2) after open-heart surgery in ICU. After 2 or 3 hours from administration of COL, heart rate and cardiac index increased, and pulmonary artery pressure and central venous pressure decreased significantly, but blood pressure and systemic venous oxygen saturation did not show significant change. In conclusion, COL improved hemodynamics through positive inotropic and vasodilator effects without hypotension. We should investigate more proper usage of this drug to avoid such side effects as tachycardia and arrhythmia, which occurred in some cases.

Development of acute myeloid leukemia after chemotherapy for osteosarcoma

The current study describes two patients with osteosarcoma who had acute myeloid leukemia develop after treatment with multiagent chemotherapy. The incidence density for the chemotherapy protocol was 129.8 per 10,000 person-year of followup. Karyotype analysis of 16 reported patients (including the current two patients) indicated that most leukemias after treatment of osteosarcoma correlated with the use of topoisomerase II inhibitors, such as doxorubicin. The deoxyribonucleic acid-damaging activity of doxorubicin reinforced by the use of alkylating agents is highly suspected as a causative event in the development of leukemia after treatment of osteosarcoma. As the next step in the development of treatment for patients with osteosarcoma, the type and intensity of treatment must be evaluated to minimize possible leukemogenic effects without compromising the potential for cure.

Loss of the mitochondrial Hsp70 functions causes aggregation of mitochondria in yeast cells

Ssc1p, a member of the Hsp70 family in the mitochondrial matrix of budding yeast, mediates protein import into mitochondria and prevents irreversible aggregation of proteins in the mitochondrial matrix during folding/assembly or at elevated temperature. Here, we show that functional inactivation of the mitochondrial Hsp70 system causes aggregation of mitochondria. When temperature-sensitive mitochondrial Hsp70 mutant cells were incubated at restrictive temperature, a tubular network of mitochondria was collapsed to form aggregates. Inhibition of protein synthesis in the cytosol did not suppress the mitochondrial aggregation and functional impairment of Tim23, a subunit of mitochondrial protein translocator in the inner membrane, did not cause mitochondrial aggregation. Therefore defects of the Hsp70 function in protein import into mitochondria or resulting accumulation of precursor forms of mitochondrial proteins outside the mitochondria are not the causal reason for the aberrant mitochondrial morphology. By contrast, deletion of Mdj1p, a functional partner for mitochondrial Hsp70 in prevention of irreversible protein aggregation in the matrix, but not in protein import into mitochondria, caused aggregation of mitochondria, which was enhanced at elevated temperature (37°C). The aggregation of mitochondria at 37°C was reversed when the temperature was lowered to 23°C unless protein synthesis was blocked. On the basis of these results, we propose that the mitochondrial matrix contains a protein that is responsible for the maintenance of mitochondrial morphology and requires mitochondrial Hsp70 for its function.

Regional differences in myocardial work of the left ventricle in patients with idiopathic dilated cardiomyopathy: Implications for the surgical technique used for left ventriculoplasty

OBJECTIVES

In this study we measured regional myocardial work of the left ventricle in patients with dilated cardiomyopathy and examined the existence of regional differences in myocardial work.

BACKGROUND

Left ventriculoplasty aims to improve the ejection fraction by excluding a region with decreased wall motion and decreasing wall tension. If regional differences in myocardial work are present, left ventriculoplasty will be more effective when a region with decreased myocardial work is excluded.

METHODS

The study group consisted of 10 patients with idiopathic dilated cardiomyopathy. Regional work of the ventricle normalized to a unit volume of myocardium (RWM) is given as follows: RWM = -integral sigma(d)[ln(1/H)], where sigma is mean wall stress, and H is wall thickness of the region. After right-sided catheterization, left ventricular pressure was measured with a 3F micromanometer catheter. Echocardiography was performed simultaneously, and a short-axis view of the left ventricle at the level of the papillary muscles was obtained. The derived M-mode image was recorded with left ventricular pressure. sigma-ln(1/H) relations for the ventricle were delineated, and regional work of the interventricular septum and posteroinferior wall were determined. Relationships between regional work of the myocardium and wall thickness, interventricular septal regional work of the myocardium and right ventricular systolic pressure, and right ventricular ejection fraction were also studied.

RESULTS

Interventricular septal regional work ranged from -0.84 to 3.34 mJ/cm3 (0.74 +/- 1.51 mJ/cm3). Posteroinferior wall regional work ranged from 1.59 to 4.29 mJ/cm3 (2.77 +/- 0.86 mJ/cm3). In the study group, interventricular septal regional work was lower than posteroinferior wall regional work (P <.05). In 8 of these 10 patients, interventricular septal regional work was lower than posteroinferior wall regional work. In the other 2 patients, conversely, interventricular septal regional work was higher than posteroinferior wall regional work.

CONCLUSIONS

The existence of differences in regional work between the interventricular septum and the posteroinferior wall suggests the importance of the evaluation of regional work in the selection of an effective treatment for dilated cardiomyopathy.