Bio-artificial periosteum for severe open fracture--an experimental study of osteogenic cell/collagen sponge composite as a bio-artificial periosteum

In an attempt to reduce complications in cases of severe open fracture, we developed a bio-artificial periosteum composed of osteogenic cells and collagen sponge. In the present study, we evaluated the osteogenic potential of the bio-artificial periosteum in vivo and in vitro. After 4-week incubation in vitro, the bio-artificial periosteum had high alkaline phosphatase activity and osteocalcin content. Moreover, energy dispersive X-ray analysis revealed numerous crystal structures consisting of P and Ca on the surface of the bio-artificial periosteum. Using a rat model for severe bone injury, we examined the bone formation process in defect sites covered with the bio-artificial periosteum. New bone formation occurred in the central part of the bone defect as well as at the bone edge. We conclude that by using the bio-artificial periosteum, the fracture site benefited from an improved osteogenic environment. These results indicate that a clinical trial to further evaluate this technique should be conducted.     

Stimulatory effects of statins on bone marrow-derived mesenchymal stem cells. Study of a new therapeutic agent for fracture

Recent studies have reported that statins, inhibitors of hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase, increase bone formation in osteoblasts in vitro, suggesting that statins may have a new therapeutic application in the treatment of osteoporosis. During the reparative phase of healing of bone fractures, bone marrow-derived mesenchymal stem cells differentiate into osteoblasts or chondrocytes to form callus. If statins also stimulate bone formation in bone marrow-derived mesenchymal stem cells they may have beneficial effects in the treatment of bone fractures. In this study, we assessed the effect of statins on bone formation in rat bone marrow-derived mesenchymal stem cells in vitro. The statins fluvastatin, simvastatin and pravastatin did not significantly enhance mineralization, alkaline phosphatase (ALP) activity and bone gra protein (BGP, osteocalcin). These findings suggest that statins do not increase bone formation in bone marrow-derived mesenchymal stem cells.     

Pulmonary endarterectomy: experience and lessons learned in 1,500 cases

BACKGROUND: The incidence of pulmonary hypertension resulting from chronic thrombotic occlusion of the pulmonary arteries is significantly underestimated. Although medical therapy for the condition is supportive only, surgical therapy is curative. Our pulmonary endarterectomy program was begun in 1970, and 188 patients were operated on in the subsequent 20 years. With the increased recognition of the disease and the success of operative therapy, however, more than 1,400 operations have been done since 1990 at our center. METHODS: The safety and efficacy of the operation was assessed with changes made through increased experience. We examined in detail the results of our last 500 consecutive patients. RESULTS: Median sternotomy, cardiopulmonary bypass, profound hypothermia, and circulatory arrest were found to be essential to the success of the operation. All occluding material could be removed at operation. We currently believe that there is no degree of embolic occlusion within the pulmonary vascular tree that is inaccessible and no degree of right ventricular impairment or any level of pulmonary vascular resistance that is inoperable. With shorter cardiac arrest periods and the use of a cooling jacket to the head, cerebral impairment has been eliminated. The pulmonary artery pressures and pulmonary vascular resistance in a recent cohort of 500 patients is examined. The mortality rate for the operation has been reduced steadily, and was 22 of the last 500 patients operated on (4.4%). CONCLUSIONS: The operation is considered curative and therefore greatly superior to transplantation for this condition. Current techniques of operation make the procedure relatively safe.     

Omental Flap in Pancreaticoduodenectomy for Protection of Splanchnic Vessels

Intraabdominal bleeding, the most life-threatening complication following pancreaticoduodenectomy (PD), most often is associated with failure of a pancreaticojejunostomy anastomosis or with intraabdominal infection. We investigated whether placement of an omental flap around the splanchnic vessels in PD could reduce the occurrence of intraabdominal bleeding and other postoperative complications. One hundred consecutive patients who underwent PD at the authors’ institution between January 2000 and October 2004 were enrolled in this prospective study. After dissection of the hepatoduodenal ligament, the major splanchnic arteries and the portal vein were covered by the omental flap. Preoperative condition, incidence of pancreatic fistula, intra-abdominal bleeding, other complications, treatment mortality, and hospital stay were analyzed for interrelationships. The frequency of pancreatic fistula (20%) differed little from those in previous reports. However, intraabdominal bleeding was observed in only 1 (1.0%) patient, who was considered to have too thin a flap. No intraabdominal abscess was encountered. No mortality or complications occurred in relation to the omental flap. Thus, wrapping an omental flap around dissected splanchnic vessels in PD reduced postoperative intraabdominal bleeding and infection, but failed to prevent pancreatic fistulas.     

Molecular diagnosis of gastric cancer: present and future

Although histopathological diagnosis is extremely useful for the definitive as well as the supportive diagnosis of gastric cancer in clinical practice, it is limited in certain respects. Over the past 15 years, integrated research in molecular pathology has clarified the details of genetic and epigenetic abnormalities of cancer-related genes in the course of the development and progression of gastric cancer. These abnormalities, which include telomerase activation, genetic instability, and abnormalities in oncogenes, tumor suppressor genes, cell-cycle regulators, cell adhesion molecules, and DNA repair genes, could be effective markers in the molecular diagnosis of gastric cancer. It is possible that the molecular analysis of these alterations in histopathology specimens may overcome deficiencies in diagnoses that depend only on histomorphology, and, consequently, we may be able to improve the differential diagnosis of cancer, obtain information on the grade of malignancy, and identify patients at high risk of developing multiple primary cancers. In Hiroshima, we have established a system of molecular-pathological diagnosis as a routine service; about 5000 lesions of the stomach have been subjected to this diagnosis, and much useful information has been obtained. In the near future, genetic analysis by means of DNA microarray may become routine in the diagnosis of gastric cancer. Genetic analysis of histopathology specimens may make clear the characteristics of individual cancers; indicating the common and specific features of molecular pathogenesis that may be directly connected with gene therapy or molecular-targeted therapy. By analyzing the relationship between single-nucleotide polymorphisms and cancer susceptibility, we will be able to obtain information on cancer prevention from histopathology samples. Received: May 21, 2001 / Accepted: July 3, 2001     

Renoprotective effects of tea catechin in streptozotocin- induced diabetic rats

Tea catechins, a class of flavonoids, are suggested to have biological effects, possibly mediated through their antioxidative properties. Recent data indicated that tea catechins suppressed proliferative changes in glomeruli and inhibited the development of glomerulosclerosis in partially nephrectomized rats. We thus sought to determine whether tea catechins may protect against renal dysfunction in streptozotocin-induced diabetic rats. Four groups of male Sprague-Dawley rats (n=11–15 per group), with and without streptozotocin-induced diabetes, were treated with and without catechins (5 mg/day) administered in the drinking water for 12 weeks. At the end of the treatment period, 24-hour urinary albumin excretion rate (AER), serum lipid peroxides as thiobarbituric acid reactive substrates (TBARS) and blood pressure were measured. Renal glomerular volume and interstitial fibrosis were assessed morphologically. Albuminuria developed progressively in untreated diabetic rats, resulting in a mean AER of 559±124 (mean±SE) versus 63±7 μg/day/100 g body weight in non-diabetic rats at 12 weeks (P<0.001). Catechin treatment significantly reduced AER to 287±56 μg/day/100 g body weight in diabetic rats (P=0.017 versus untreated diabetic rats). Increased interstitial fibrosis in the kidney, observed in untreated diabetic rats, was completely normalized with catechin treatment. Serum levels of TBARS and blood pressure were comparable among the four groups. In conclusion, administration of tea catechin retards the progression of functional and morphological changes in the kidney of streptozotocin-induced diabetic rats.     

Carbonic anhydrase II is a tumor vessel endothelium-associated antigen targeted by dendritic cell therapy.

Tumor-associated antigens are promising candidates as target molecules for immunotherapy and a wide variety of tumor-associated antigens have been discovered through the presence of serum antibodies in cancer patients. We previously conducted dendritic cell therapy on 10 malignant melanoma patients and shrinkage or disappearance of metastatic tumors with massive necrosis occurred in two patients. In this study, we found a 29-kDa protein against which antibody was elicited by dendritic cell therapy in one of the two patients. Matrix-assisted laser desorption ionization-time of flight/mass spectrometry analysis of the protein isolated by two-dimensional electrophoresis combined with Western blots revealed that the 29-kDa protein was carbonic anhydrase II (CA-II). Immunohistochemistry of the tumors and normal tissues showed that CA-II was expressed in the tumor vessel but not in normal vessel endothelium. CA-II expression in tumor endothelium was observed as well in other cancers including esophageal, renal, and lung cancers. In an in vitro angiogenesis model, CA-II expression of normal human vein endothelial cells was significantly up-regulated when cells were cultured in the acidic and hypoxic conditions indicative of a tumor environment. These findings suggest that CA-II is a tumor vessel endothelium-associated antigen in melanoma and other cancers, and elicitation of serum anti-CA-II antibody by dendritic cell therapy may be associated with good clinical outcome including tumor reduction.