Biomedical subjects
N Yuasa
Publications and source records attributed to N Yuasa.
Complete, long-lasting protection against lethal infectious bursal disease virus challenge by a single vaccination with an avian herpesvirus vector expressing VP2 antigens.
Marek's disease herpesvirus is a vaccine vector of great promise for chickens; however, complete protection against foreign infectious diseases has not been achieved. In this study, two herpesvirus of turkey recombinants (rHVTs) expressing large amounts of infectious bursal disease virus (IBDV) VP2 antigen under the control of a human cytomegalovirus (CMV) promoter or CMV/beta-actin chimera promoter (Pec promoter) (rHVT-cmvVP2 and rHVT-pecVP2) were constructed. rHVT-pecVP2, which expressed the VP2 antigen approximately four times more than did rHVT-cmvVP2 in vitro, induced complete protection against a lethal IBDV challenge in chickens, whereas rHVT-cmvVP2 induced 58% protection. All of the chickens vaccinated with rHVT-pecVP2 had a protective level of antibodies to the VP2 antigen at the time of challenge, whereas only 42 and 67% of chickens vaccinated with rHVT-cmvVP2 or the conventional live IBDV vaccine, respectively, had the antibodies. The antibody level of chickens vaccinated with rHVT-pecVP2 increased for 16 weeks, and the peak antibody level persisted throughout the experiment. The serum antibody titer at 30 weeks of age was about 20 or 65 times higher than that of chickens vaccinated with rHVT-cmvVP2 or the conventional live vaccine, respectively. rHVT-pecVP2, isolated consistently for 30 weeks from the vaccinated chickens, expressed the VP2 antigen after cultivation, and neither nucleotide mutations nor deletion in the VP2 gene was found. These results demonstrate that the amount of VP2 antigen expressed in the HVT vector was correlated with the vaccine efficacy against lethal IBDV challenge, and complete protective immunity that is likely to persist for the life of the chickens was induced.
Types of lumbar herniated disc and clinical course.
STUDY DESIGN: A retrospective study of different types of herniated discs and duration of symptoms in patients with lumbar disc herniation, and a trial of longer conservative treatment to reduce the number of operations. OBJECTIVE: To determine whether noncontained and contained herniated discs have different clinical courses and to evaluate the results of the clinical trial of longer and vigorous conservative treatment. SUMMARY OF BACKGROUND DATA: The possibility of a difference in clinical features between contained and noncontained disc herniation has been suggested previously. METHODS: In the first study, the medical history and intraoperative findings of 156 patients who had undergone herniotomy were reviewed. In the second study, conservative treatment of at least 2 months' duration was recommended for all patients with lumbar disc herniation. RESULTS: In the first study, patients with noncontained disc herniation had a shorter preoperative clinical course than those with contained disc herniation. It was rare for noncontained herniation to require surgery 4 months or more after the onset of symptoms. In the second study, the authors' protocol reduced the number of herniotomies required, especially the number of operations for the patients with noncontained disc herniation. CONCLUSIONS: The authors believe that patients with noncontained lumbar disc herniation can be treated without surgery, if these patients can tolerate the symptoms for the first 2 months.
Bilirubin impairs bactericidal activity of neutrophils through an antioxidant mechanism in vitro.
BACKGROUND: Liver failure accompanied by hyperbilirubinemia after major hepatic resection is profoundly associated with septic complications. Although the immune dysfunction in cholestasis has been intensively investigated, the contribution of increased serum bilirubin to the impaired resistance to bacterial infection remains to be elucidated. Because bilirubin possesses an antioxidant activity, we hypothesized that bilirubin may scavenge reactive oxygen species (ROS) produced by neutrophils and consequently impair neutrophil bacterial killing. To address this, we evaluated the effects of bilirubin on the bactericidal activity of ROS or of neutrophils in vitro. MATERIALS AND METHODS: The antioxidant activity of bilirubin was determined using an ROS-sensitive fluorophore, dichlorofluorescin diacetate (DCFH-DA). Bilirubin concentration in the buffer solution was monitored spectorophotometrically after incubation with ROS. The effect of bilirubin on killing of Escherichia coli by ROS or by isolated human neutrophils was determined by counting the viable E. coli after incubation on nutrient agar. RESULTS: The bilirubin concentration in the buffer solution was decreased by the addition of hydrogen peroxide, especially in the presence of peroxidase or ferrous iron. DCFH-DA oxidation by ROS or activated neutrophils was inhibited by bilirubin in a dose-dependent manner. The bactericidal activity of ROS or of isolated neutrophils was significantly attenuated by bilirubin. CONCLUSIONS: Bilirubin impairs bactericidal activity of neutrophils through scavenging ROS. Increased levels of serum bilirubin may well be responsible for the impaired bacterial clearance in patients with hyperbilirubinemia.
Five-year survivors after aggressive surgery for stage IV gallbladder cancer.
PURPOSE: To describe 5-year survivors after radical surgery for stage IV gallbladder cancer and to determine the characteristics leading to potential long-term survival. METHODS: Of 59 patients undergoing radical resection for stage IV disease between 1979 and 1994, 6 patients who have survived for more than 5 years were followed up. RESULTS: Three patients had developed obstructive jaundice due to involvement of the hepatic hilum, but the other three had not. The jaundiced patients had remarkable tumor spread over the bile duct and right hepatic artery within the hepatoduodenal ligament. However, the proper and left hepatic arteries and the portal trunk and its left branch were free from tumor involvement. The nonjaundiced patients had N1 or N2 lymph node metastasis. However, none underwent bile duct resection or pancreatoduodenectomy to establish radical lymphadenectomy. CONCLUSIONS: Selected patients with stage IV gallbladder cancer may be candidates for 5-year survival when the primary tumor is fairly localized even if it forms a large mass and involves neighboring organs including the hepatic duct, lymph node metastasis is limited to N1 and N2 except for the celiac and superior mesenteric nodes and is less infiltrative, and distant metastasis including that in the paraaortic area is absent.
Images in focus. Peribiliary cysts both in the cystic duct and in the intrahepatic biliary tract.
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Early basaloid squamous cell carcinoma of the esophagus.
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Identification of a genetic determinant of pathogenicity in chicken anaemia virus.
The molecular basis of pathogenicity of the chicken anaemia virus (CAV) needs to be clarified in order to develop a safe, live virus vaccine. In this study, several high- and low-pathogenic infectious DNA clones were obtained from field virus samples after 12 or 38 passages in MDCC-MSB1 cells. The high-pathogenic clones induced a low haematocrit, low weight gain and high mortality. Nucleotide sequence analyses identified one amino acid, at residue 394 of the VP1 capsid protein, as a major determinant of pathogenicity. To determine the role of this amino acid in pathogenicity, chimeric infectious DNA clones and point-mutated clones were used for chicken pathogenicity tests. These analyses clearly demonstrated that residue 394 of VP1 was crucial for the pathogenicity of CAV; all of the cloned viruses with glutamine at this position were highly pathogenic, whereas those with histidine had low pathogenicity. Low-pathogenic CAV, based on an infectious DNA clone, is a candidate for a genetically homogeneous and stable CAV live vaccine.
Clinicopathological features of superficial spreading and nonspreading squamous cell carcinoma of the esophagus.
OBJECTIVES: Superficially spreading carcinoma of the esophagus, consisting mainly of intraepithelial carcinoma, is not as rare as was previously thought. Despite the surgical significance of this entity, no general definition has been established, and the clinical features of this disease remain to be clarified. METHODS: A total of 54 patients with superficial carcinoma of the esophagus (defined as carcinoma limited to the epithelium or superficially invading the lamina propria or submucosa) were classified into two groups according to the longitudinal extent of the lesion. A total of 13 patients with superficially spreading carcinoma (defined as a superficial carcinoma measuring >5 cm and consisting mainly of intraepithelial carcinoma) were compared to 41 patients with nonspreading esophageal carcinoma. RESULTS: One patient with superficially spreading carcinoma had a positive resection margin because of multiple cancerous lesions. The only significant difference in the clinical and pathological features of the two groups was a higher prevalence of associated multiple cancerous lesions in patients with the superficially spreading type. CONCLUSIONS: Superficially spreading carcinoma of the esophagus is often associated with multiple cancerous lesions. For endoscopists and esophageal surgeons, it is important to define the proximal extent of intraepithelial cancer and the presence of multiple cancerous lesions to perform curative resection.
[Extended liver resection for hilar cholangiocarcinoma].
Liver resection for hilar cholangiocarcinoma should be designed for individual patients, based on both precise diagnosis of cancer extent and accurate evaluation of hepatic functional reserve. Therefore we have developed various types of hepatic segmentectomy. Combined caudate lobectomy is essential in every patient with separated hepatic confluence. So-called extensive hepatectomy, resection of 50% or more of the hepatic mass, includes right lobectomy and right or left trisegmentectomy. Right lobectomy with caudate lobectomy is indicated when the progression of cancer is predominant in the right anterior and posterior segmental bile ducts. The plane of liver transection is along the Cantlie line, and the left hepatic duct is divided just at the right side of the umbilical portion of the left portal vein. Right trisegmentectomy with caudate lobectomy is performed in carcinoma which involves the right hepatic ducts in continuity with the left medial segmental bile duct. The umbilical portion of the left portal vein is freed from the umbilical plate by dividing the small portal branches arising from the cranial side of the umbilical portion. Then the left lateral segmental bile ducts are exposed and divided at the left side of the umbilical portion of the left portal vein. Left trisegmentectomy with caudate lobectomy is suitable for carcinoma which involves the left intrahepatic bile duct in continuity with the right anterior segmental bile duct. Liver transection is advanced along the right portal fissure. The right posterior segmental bile duct is usually divided distal to the confluence of the inferior and superior branches.
Treatment of spontaneous esophageal rupture with a covered self-expanding metal stent.
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Persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency.
Chicken anaemia virus (CAV) infectivity and the effect of highly virulent infectious bursal disease virus (hv IBDV) infection on CAV's infectivity were examined in chickens inoculated with CAV or inoculated dually with CAV and hv IBDV. Five chickens inoculated dually with hv IBDV at 35 days old and then with CAV at 40 days old exhibited no clinical signs of disease, but showed atrophic bursae of Fabricius when necropsied 4 weeks later. Upon examining the chickens at 7 days postinoculation (dpi) with CAV, it was found that hv IBDV infection had inhibited production of virus neutralising (VN) antibody to CAV, and that it was possible to recover CAV from plasma of these chickens. Although VN antibody to CAV appeared after 14 dpi, CAV was recovered from blood cells (BC s) at high titres ranging from 10(2.5)to 10(5.5)TCID(50)/0.1 ml, 7 to 28 dpi in IBDV -induced immunosuppressed chickens. In addition, CAV was sporadically recovered, using rectal swabs, from the dually inoculated chickens at low titers, ranging from 10(1.0)to 10(2. 0)TCID(50)/0.1 ml). In contrast, although CAV was recovered from BC s in most of the chickens inoculated with CAV alone, the titers were lower (10(1.0)to 10(2.5)TCID(50)/0.1 ml). No CAV was detected from the rectal swabs of these chickens. The results of virus recovery were confirmed by polymerase chain reaction. This study first examined the persistency of CAV in BC s and the effective enhancement of primary CAV infection as a result of immunosuppression caused by hv IBDV infection.
[Treatment of recurrent cancer after surgery for biliary malignancies].
Our strategy for recurrent tumor after surgical resection for biliary malignancies, especially for hilar cholangiocarcinoma, is described. One hundred and thirty-three patients with hilar cholangiocarcinoma underwent curative resection in our department until November, 1998, and recurrent carcinomas have been pointed out in 73 patients (54.9%). The site of recurrence was peritoneum (21 cases), liver (16 cases), pre-caval and retro-duodenal space (15 cases), hepatic hilum (11 cases), lymph node (9 cases), bone (6 cases), sinus tract of percutaneous transhepatic biliary drainage (PTBD) (5 cases) and so on. Surgical resection was applied to recurrent carcinomas after careful evaluation, and 9 patients underwent surgical resection of the recurrent tumor: sinus tract of PTBD in the abdominal and/or chest wall (4 cases), lymph node (2 cases), liver (1 case), hepaticojejunostomy (1 case) and duodenum (1 case). There were three hospital death patients. Other six patients survived for 16 months on an average (11-20 months) after surgery for recurrent tumor. PTBD for recurrent cancer at the hepatic hilum and gastrojejunostomy for local recurrence around the duodenum improved quality of life of patients. Radiation therapy for bone metastasis or local recurrence at the hepatic hilum was sometimes very effective. Effect of systemic or transarterial chemotherapy is still unknown.
Analysis of optimal range of socket orientations in total hip arthroplasty with use of computer-aided design simulation.
A three-dimensional computer-aided design model of a total hip replacement was used to study the effects of anteversion and abduction of the acetabular component and anteversion and varus-valgus angulation of the femoral component on the range of hip flexion and extension that could be obtained without component impingement. Impingement of the component was defined as impingement between the neck of the femoral component and the edge of the acetabular component. To achieve an angle of hip flexion greater than 90 degrees and an extension angle greater than 30 degrees without component impingement, the optimal angulations were found to be between 1 and 30 degrees of anteversion and 30 and 50 degrees of abduction of the acetabular component, as well as 10 degrees of anteversion of the femoral component. When the valgus angulation of the femoral component was reduced from 7 to 0 degrees, the allowable range of flexion without impingement increased under the same conditions of acetabular-component orientation and femoral-component anteversion. Significant inverse correlations were found between the anteversion angle of the acetabular component and both the lumbar lordosis angle and the sacrohorizontal angle.
Rapid induction of lymphoid leukosis and ascites by avian leukosis virus from a lymphoid leukosis cell line.
To examine whether a lymphoid leukosis (LL) cell line releases an LL-specific avian leukosis virus (ALV) or not, two viral materials, culture fluid and a concentrated viral material from an LL-cell line, were inoculated into a total of 74 day-old chicks of line 15I in 5 experiments. Spectrum of diseases induced, their incidence and incubation periods to onset were examined. Fifteen chicks were inoculated with the culture fluid and 9 (60%) developed ascites [59-119 days post inoculation (dpi); geometric mean (GM) of dpi, GM: 89.6)], but LL was not induced in any chicks inoculated. Fifty-nine chicks were inoculated with the concentrated viral material and LL was recognized in 13 (22.0%) (27-74 dpi; GM: 48.4), ascites with LL in 11 (18.6%) (34-75 dpi; GM: 41.3), ascites alone in 21 (35.6%) (32-83 dpi; GM: 48.2), erythroblastosis in 2 (3.4%) (70-102 dpi; GM: 84.5), and other diseases in 12 (20.3%) (43-102 dpi; GM: 61.8). LL lesions were frequently observed in the liver, spleen, kidneys, bursa of Fabricius (bursa), bone marrow and gonads. Mild lymphocytic foci in some visceral organs and perivascular cuffing in the central nervous system were observed mainly in several chicks diagnosed as having complication of ascites with LL or other diseases. In addition to these lesions, atrophy of bursa and thymuses was recognized in them. No antibodies against Marek's disease virus (MDV) and reticuloendotheliosis virus were detected in 36 sera taken from the chicks inoculated with the concentrated viral material. Serotype 2 MDV was isolated from the buffy coat of some inoculated chicks. These results suggest that the properties of ALV inoculated and immunosuppression caused by inoculation with high doses of ALV are involved in rapid induction of LL and expression of pathogenicity of serotype 2 MDV released from the LL cell line and included in the viral inoculum. This is the first report describing the rapid induction of LL and ascites in chicks.
[Differences in strategies for carcinoma of the pancreas between Japan and western countries].
Differences in surgical strategies for carcinoma of the pancreas, especially the head of the pancreas, between Japan and western countries are described. In Japan, pancreatoduodenectomy (PD) or pylorus-preserving PD, accompanied by extensive lymph node and extra-pancreatic nerve plexus dissection, is performed for this difficult disease. Combined resection of the portal vein is also done when needed (radical resection). In western countries, a standard PD does not include extensive lymph node dissection and portal vein resection (standard resection). Although some Japanese surgeons reported about 30% postoperative 5-year survival rates after radical resection and some American surgeons achieved about 20% 5-year survival rates after standard resection, there are some problems with comparison of these results. Surgeons in Japan and western countries use different staging systems, namely, the classifications of the Japanese Pancreas Society and the Union of Internationale Contre le Cancer (UICC). It is essential to establish a more accurate international staging system to scientifically evaluate the difference in surgical results between Japan and western countries.
[Value of paraaortic lymphadenectomy for gallbladder carcinoma].
Seven reports of paraaortic lymphadenectomy for advanced carcinoma of the gallbladder were reviewed and positive paraaortic nodes were found in 20-40% of the resected patients and 10-15% of those with subserosal cancer invasion. The rate of patients with positive paraaortic nodes/all patients with positive nodes was 30-50%. Paraaortic lymphadenectomy did not improve the surgical outcome, and most of the patients with positive paraaortic nodes died within 1 year even after aggressive surgery with extensive lymph node dissection. Therefore it is important to clarify the value of paraaortic lymph node dissection for patients with possibly positive paraaortic node metastasis and those with histologically positive nodes excluding the paraaortic area. Although pancreatoduodenectomy for prophylactic lymphadenectomy around the head of the pancreas has been carried out in some institutions, the procedure does not seem to be effective because the main lymphatic route from the gallbladder has a direct connection with the paraaortic nodes via the pericholedochal, periportal, and/or the posterior nodes along the common hepatic artery. The present authors recommend a D2 plus paraaortic lymph node dissection (ext D2) as a standard surgical strategy for carcinoma of the gallbladder.