The effect of Goldbonder on the adhesion between porcelain and pure titanium.

The present study examines the effect of a Goldbonder on the adhesion between titanium and porcelain as measured by the strain energy release rate (G) associated with the interfacial fracture of porcelain and titanium. The influence of surface treatment of titanium prior to Goldbonder application was also examined. The porcelain side of the specimens was notched to the interface with a thin diamond saw, and then a pre-crack was made at the metal-porcelain interface by a special jig. The samples were subjected to a four-point bending test resulting in stable crack extension from which G was calculated. Both the cracked cross-section of interface and peeled fracture surface were examined with scanning electron microscope (SEM). The mean G values were 81.57 +/- 10.34, 46.01 +/- 14.83, and 15.98 +/- 1.76 J m(-2) for the sandblasted surface with the Goldbonder, polished surface with the Goldbonder, and sandblasted surface with the Pastebonder, respectively. The G values revealed significant differences (P < 0.01) between Goldbonder and Pastebonder, and between the sandblasted and polished surfaces with Goldbonder. The SEM photographs and elemental analysis showed that Goldbonder developed both chemical and mechanical bonding to titanium and porcelain.

A possible role of VEGF in osteolytic bone metastasis of hepatocellular carcinoma.

The incidence of bone metastasis was around 13% in 404 patients with hepatocellular carcinoma (HCC) who underwent treatment at the National Kyushu Cancer Center between 1988-97, which is a high value among various cancers. This is, in part, due to the prolonged survival time of HCC patients in recent years. Serum vascular endothelial growth factor (VEGF) levels were significantly elevated in HCC patients with bone metastases as compared to those in patients with liver cirrhosis/chronic hepatitis and HCC patients without bone metastasis. VEGF was positively stained in both the primary lesion and bone metastasis of HCC by immunohistochemistry. In the process of bone metastasis, an increase in bone resorption is a crucial step prior to invasion of the bone. VEGF, the most important angiogenic factor, has been shown to stimulate bone resorption through its effects on osteoclasts. Thus, HCC cells reach the bone marrow space, and then secrete VEGF which facilitates osteolytic bone metastasis. VEGF may also facilitate tumor growth in the bone by acting as an angiogenic factor once invasion of the bone is complete. This might be another reason for the high incidence of bone metastasis in HCC.

Matrix metalloproteinase 2 gene knockout has no effect on acute brain injury after focal ischemia.

Matrix metalloproteinases (MMPs) may contribute to tissue damage after cerebral ischemia. In this study, wildtype and MMP-2 knockout mice were subjected to permanent and transient (2 h) occlusions of the middle cerebral artery. Gelatin zymography showed that MMP-9 levels were increased in all brains after ischemia. MMP-2 levels did not show a significant increase in wildtype mice, and were not detectable in knockout mice. Laser doppler flowmetry demonstrated equivalent ischemic reductions in perfusion in wildtype and knockout mice. In both permanent and transient occlusion paradigms, there were no statistically significant differences between wildtype and knockout mice in terms of 24 h ischemic lesion volumes. These data suggest that MMP-2 does not contribute to acute tissue damage in this model of focal ischemia.

Effects of matrix metalloproteinase-9 gene knock-out on the proteolysis of blood-brain barrier and white matter components after cerebral ischemia.

Deleterious processes of extracellular proteolysis may contribute to the progression of tissue damage after acute brain injury. We recently showed that matrix metalloproteinase-9 (MMP-9) knock-out mice were protected against ischemic and traumatic brain injury. In this study, we examined the mechanisms involved by focusing on relevant MMP-9 substrates in blood-brain barrier, matrix, and white matter. MMP-9 knock-out and wild-type mice were subjected to transient focal ischemia. MMP-9 levels increased after ischemia in wild-type brain, with expression primarily present in vascular endothelium. Western blots showed that the blood-brain barrier-associated protein and MMP-9 substrate zonae occludens-1 was degraded after ischemia, but this was reduced in knock-out mice. There were no detectable changes in another blood-brain barrier-associated protein, occludin. Correspondingly, blood-brain barrier disruption assessed via Evans Blue leakage was significantly attenuated in MMP-9 knock-out mice compared with wild types. In white matter, ischemic degradation of the MMP-9 substrate myelin basic protein was significantly reduced in knock-out mice compared with wild types, whereas there was no degradation of other myelin proteins that are not MMP substrates (proteolipid protein and DM20). There were no detectable changes in the ubiquitous structural protein actin or the extracellular matrix protein laminin. Finally, 24 hr lesion volumes were significantly reduced in knock-out mice compared with wild types. These data demonstrate that the protective effects of MMP-9 gene knock-out after transient focal ischemia may be mediated by reduced proteolytic degradation of critical blood-brain barrier and white matter components.

Thermal expansion coefficient of titanium casting.

A reliable measurement of the thermal expansion coefficient (alpha) value is required to achieve a positive thermal mismatch between metal and porcelain for porcelain-fused to metal crowns. Heating rate and specimen conditions may significantly influence the alpha value and the effects of these factors were studied. Commercially pure cast titanium rods, 'as cast' and sandblasted, were heated at various conditions. According to this study, the discrepancy of alpha values between heating and cooling conditions was insignificant when the heating (cooling) rate was reduced to 1 degrees C min(-1). It was revealed that alpha values obtained from 1 degrees C min(-1) cooling rates should be utilized. Dental porcelain with an alpha value lower than 8.5 x 10(-6) degrees C will be suitable for titanium-ceramic applications.

Intraductal papillary-mucinous tumors of the pancreas: differential diagnosis between benign and malignant tumors by endoscopic ultrasonography.

OBJECTIVES: Recently, intraductal papillary-mucinous tumor (IPMT) of the pancreas has increasingly been recognized. However, differential diagnosis between benign and malignant IPMT is often difficult using conventional imaging modalities. The purpose of this study was to retrospectively investigate the value of endoscopic ultrasonography (EUS) for differentiating malignant from benign IPMT. METHODS: A total of 51 patients with IPMT were preoperatively examined by EUS. The endosonograhic findings were compared with histopathological findings of the resected specimens. RESULTS: In main duct type IPMT, the diameter of the main pancreatic duct (MPD) was > or =10 mm in seven of the eight malignant tumors, compared with two of the seven benign tumors (p < 0.05). In branch duct type IPMT, three of the four large tumors (>40 mm) with irregular thick septa were malignant lesions. In both main duct type IPMT and branch duct IPMT, eight patients had large mural nodules (>10 mm); seven of the eight tumors were malignant and one of the eight tumors was benign. When the tumor was diagnosed as malignant according to above three findings, EUS was able to differentiate between malignant and benign IPMT with an accuracy of 86%. CONCLUSIONS: Main duct type tumors with > or =10 mm dilated MPD, branch duct type tumors (>40 mm) with irregular septa, and large mural nodules (>10 mm) strongly suggest malignancy on EUS. EUS would be a useful modality for differentiating between benign and malignant IPMT.

Protective effects of pamiteplase, a modified t-PA, in a rat model of embolic stroke.

The effects of alteplase (tissue plasminogen activator, t-PA) and pamiteplase (a modified t-PA with longer half-life and increased potency) were compared in a clinically relevant model of embolic stroke. Rats were treated with pamiteplase (0.5 mg/kg or 1 mg/kg bolus), alteplase (10 mg/kg infusion) or normal saline. Pamiteplase (1 mg/kg) was as effective as alteplase in reducing 24 h brain infarct volumes, neurological deficit scores and residual clot grades. Cerebral blood flow recovery at 30 min after thrombolytic treatment was partial and did not correlate with 24 h infarct volumes or neurological deficits. However, there was good correlation between 24 h residual clot grades and infarct volumes, suggesting a delayed timeframe for pamiteplase- and alteplase-induced reperfusion.

Successful treatment of large malignant tumor involving the skull base by radiosurgery combined with intraarterial chemotherapy and embolization.

Stereotactic radiosurgery can be used to treat malignant tumors involving the skull base. While it avoids extensive sacrifice of the normal structures surrounding the tumor, radiosurgery does not eradicate the tumor mass immediately. We present a patient with a large hypervascular malignant tumor involving the skull base that resulted in intracranial hypertension. He was successfully treated with stereotactic radiosurgery combined with intra-arterial chemotherapy and embolization of the arteries feeding the tumor. We discuss radiosurgery, chemotherapy, embolization and other therapeutic modalities for treating large malignant tumors involving the skull base.

[A case of neurofibromatosis type 1 associated with arteriovenous fistula caused by re-bleeding of a vertebral dissecting aneurysm].

We described a dissecting aneurysm of the vertebral artery (VA), which was associated with neurofibromatosis type 1 (NF1). A 41-year-old man was referred to our hospital because of abrupt, severe headache. A CT scan revealed diffuse subarachnoid hemorrhage (SAH) predominantly in the prepontine cistern. The angiograms showed a string sign in the left VA, just distal to the posterior inferior cerebellar artery (PICA). The vertebral dissection was considered responsible for SAH, and endovascular occlusion of the left VA was attempted. During the intervention, the patient complained of severe neck pain at the time of selective vertebral angiography, which revealed an arteriovenous fistula. The VA was occluded proximal to the PICA with GDC, which covered the fistula. Open surgery confirmed the two unruptured aneurysms. Intracranial dissection is rarely reported in association with NF1. However, ateriovenous fistula is not an uncommon combination with dissecting aneurysm and the extracranial segment of the VA is a characteristic target. Anatomical feasibility is conceivably the pathogenesis.

Jejunal lipomatosis with diverticulosis: report of a case.

We herein report the very rare case of a 68-year-old Japanese man with multiple jejunal lipomatosis and diverticulosis. He was admitted to our hospital with the chief complaint of melena and anemia. A barium study of the small bowel showed multiple lipomatosis and diverticulosis. An approximately 200-cm length of the jejunum was therefore resected. Thereafter, two diverticula and 215 lipomas were recognized in the resected specimen. A pathological examination showed mature adipose tissue with fibrous septa in the submucosal and muscularis propria. These findings were thus suggested to be due to the attenuation of the muscularis propria. The complications of lipomatosis are also discussed.

Autoimmune pancreatitis: CT and MR characteristics.

OBJECTIVE: Our goal was to elucidate the CT and MR imaging characteristics in patients with autoimmune pancreatitis, which is a reversible chronic pancreatitis with an autoimmune cause. CONCLUSION: On CT and MR imaging, a capsulelike rim, which is thought to correspond to an inflammatory process involving peripancreatic tissues, appears to be a characteristic finding of autoimmune pancreatitis. Also, diffuse pancreatic enlargement along with hypointensity on T1-weighted MR images and delayed enhancement on dynamic CT and MR studies are other features of this disorder.

Autoimmune pancreatitis as a new clinical entity. Three cases of autoimmune pancreatitis with effective steroid therapy.

The most common forms of chronic pancreatitis are related to alcohol ingestion, whereas the entity of non-alcohol-associated (idiopathic) pancreatitis is poorly understood. Autoimmunity has been suggested as a possible etiologic factor of idiopathic chronic pancreatitis. A total of 362 Japanese patients underwent endoscopic retrograde pancreatography (ERP) for suspected pancreatic disease, and 161 were diagnosed with chronic pancreatitis. Among them, we found three cases (1.86% incidence) of unique chronic pancreatitis, in which ERP revealed diffuse narrowing of the main pancreatic duct with an irregular wall. We diagnosed these three patients as having pancreatitis associated with an autoimmune mechanism morphologically and biochemically and started them on steroid therapy. The characteristics of the these three patients were as follows: hypergammaglobulinemia, eosinophilia, ultrasonography showing hypoehoic diffuse swelling in the pancreas (sausage-like appearance), ERP showing diffuse narrowing of the main pancreatic duct with irregular like thumbprint-like marks, reversible exocrine insufficiency, and positive anti-carbonic anhydrase II antibody. After one month of the treatment with steroids, pancreatitis dramatically improved morphologically and enzymatically. Here we describe these cases of the suspected autoimmune chronic pancreatitis. We must recognize the concept and the features of autoimmune pancreatitis in order to avoid unnecessary surgery as pancreatic cancer.

[Chronic pancreatitis and pancreatic dysfunction associated with Sjögren's syndrome].

Some pancreatic involvement was observed in Sjögren's syndrome (SS). Episodes of abdominal pain occurred infrequently in the course of SS, but there were some abnormal findings of the pancreatic functions and/or morphologic examinations. The level of serum amylase was affected by the destruction of both the pancreas and the salivary gland. Hyposecretion of bicarbonate in secretin test seemed to be characteristic in SS. ERP showed mild or moderate changes of the pancreatic duct, but their severities did not correlate with those of the salivary gland. Imaging of the pancreas tended to reveal definite abnormalities only in cases with an attack of pancreatitis. The roles of autoimmune mechanisms have been reported in pancreatitis associated with SS.