Biomedical subjects
Publications and source records attributed to H Yokoi.
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A follow-up study on pacemaker function in 15 patients with implanted cardiac pacemaker has been performed by telephone transmission. The transmitting set consisting of electrocardiograph, pacemaker pulse modulator and acoustic coupler was manipulated by the patients themselves. ECG, pacemaker pulse, and pulse rate were simultaneously transmitted through 1 channel to the receiver in our clinic. Of 56 patients with pacemaker, 15 patients were surveyed by telephone transmission. In these patients battery exhaustion was detected in 3, competition in 2, and lead fracture in 1. The fact that surveillance and follow-up of the patients with implanted cardiac pacemaker could be carried out by telephone transmission as well as by clinic visitation tells us that the telephone transmission is a useful method and plays an important role in a pacemaker clinic. Moreover our study established its further usefulness in the patient's preference due to difficulties in travelling to the pacemaker clinic and in reducing patient's anxiety.
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In this newly developed method, the ultrasonic diagnosis has become quantitative. The data will remain quantitative so far as an image storage tube is used. With the conventional storage type CRT, it is impossible to memorize the reflected echo signals of different strength levels. But with our method, it becomes possible to memorize the images according to individual levels. By the direct digitalization of the ultrasonic echo images, more information is obtained from the reflected echo signals. By processing the original information with a computer, more accurate diagnosis is possible. It is hoped and believed, that this computer aided ultrasonic examination, with single scan display in colour or black and white, will further promote ultrasonic diagnosis in future.
Parathyroid echograms were carried out in ten patients with clinical hyperparathyroidism. In seven patients, the preoperative examination was capable of detecting and localizing enlarged parathyroid glands. The echograms of parathyroid adenomas as well as carcinoma showed a characteristic cystic pattern, for which the term hollow pattern is the most suitable expression. In preoperatively detected instances using echography, the parathyroid tumors were oval-shaped and larger in size and weight. This method is a safe, simple and noninvasive technique that produces no discomfort to the patient. The reliability rate of 70 per cent in our study is acceptable. Therefore, echography of the parathyroid is applicable as a new diagnostic procedure for preoperative localization of parathyroid tumors.
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PURPOSE: Experimental autoimmune uveoretinitis (EAU) is a T-cell-mediated autoimmune disease that can be elicited in susceptible rodent strains by immunization with a retinal autoantigen, such as interphotoreceptor retinoid-binding protein (IRBP). In this study, we investigated whether there is a correlation between inflammation in the eye and T-helper (Th)1- and Th2-type responses in the lymph nodes and the spleen after immunization of B10.A mice with IRBP. METHODS: B10.A mice were immunized with IRBP emulsified with complete Freund's adjuvant (CFA), and eyes were then enucleated for histological examination of EAU at 1, 2, 4, 6, or 8 weeks after immunization. In addition, lymph node cells and spleen cells were collected, and cultured with IRBP to measure T-cell proliferation responses and Th1-type (interleukin [IL]-2, interferon [IFN]-gamma), Th2-type (IL-4, IL-10) cytokine production. RESULTS: Pathologically, severe ocular inflammation occurred 2 weeks after IRBP immunization, persisted for 2 weeks, and then gradually resolved. Interleukin-2 and IFN-gamma production were observed in draining lymph node cells at 1 and 2 weeks after IRBP immunization. Those responses then diminished, whereas IFN-gamma production by spleen cells was observed from week 1, peaked at week 4, and gradually decreased. Alternatively, significant production of IL-4 or IL-10 by draining lymph node cells was not detected at any time point. Both IL-4 and IL-10 production by spleen cells was observed at week 6. CONCLUSIONS: Th1-type responses were observed early in draining lymph nodes, then in the spleen after IRBP immunization. The levels of IFN-gamma production by spleen cells reflected the severity of EAU, confirming their pathogenic role in this disease. Th2-type responses were generated in the spleen only as the disease receded, suggesting a role for Th2 cells in the spontaneous termination of EAU.
Recently we have been performing S4a + S5 with total resection of the caudate lobe (S1) by using a dome-like dissection along the root of the middle hepatic vein at the pinnacle, which we refer to as the Taj Mahal liver parenchymal resection, for carcinoma of the biliary tract. This procedure offers the following advantages: (1) It allows total resection of the caudate lobe, including the paracaval portion (S9), and (2) because the cut surface of the liver is large, it allows intrahepatic jejunostomy to be performed more easily with a good field of view. The indications for this procedure include hilar bile duct carcinoma, gallbladder carcinoma, and choledochal cyst (type IVA). Because of the high rate of hilar liver parenchyma and caudate lobe invasion associated with hilar bile duct carcinoma, the liver must be resected. The Taj Mahal procedure is indicated in cases where extended liver resection is impossible. The dissection limits of this procedure are, on the left side, the B2+3 bifurcation at the right margin of the umbilical portion of the portal vein and, on the right side, the B8 of the anterior branch and the B6+7 bifurcation of the right posterior branch. This procedure could also be described as a reduced form of extended right hepatectomy and extended left hepatectomy. For gallbladder carcinoma, this procedure is indicated to ensure an adequate surgical margin and eradicate transvenous liver metastasis, particularly in cases of pT2 lesions. Hilar and caudate lobe invasion also occurs in liver bed-type gallbladder carcinoma, and bile duct resection and caudate lobe resection are required for the surgery to be curative. We performed this procedure in four cases of hilar bile duct carcinoma, five cases of gallbladder carcinoma, and one case each of choledochal cyst (type IVA) with carcinoma of the bile duct and gallbladder adenomyomatosis. Curative resection was possible in all except the patient with adenomyomatosis, and all of the patients are alive and recurrence free 10 to 37 months postoperatively. This procedure, in addition to preserving liver function, provides a wide field of view and facilitates reconstruction of multiple intrahepatic bile ducts. Thus it can be said to be a curative operation not only in patients considered high risk but also in those whose hilar bile duct carcinoma is limited to the bifurcation area (Bismuth type IIIa and IIIb) and in gallbladder carcinoma up to pT2 with slight extension on the hepatic side.
A rare case of malignant melanoma of the base of the tongue in a 65-year-old Japanese woman is described. The primary and metastatic tumors were treated by surgery, chemohormone and immunotherapy. There was no recurrence for 5 years after the initial diagnosis. Electron microscopy suggested that the melanosomes of the melanoma cells in the cervical lymph nodes were less mature than those in the primary melanoma cells; melanosome immaturity was consistent with a more aggressive quality.
The characteristics of cardiac rupture associated with thrombolytic therapy for acute myocardial infarction (MI) were studied in the hearts of 10 autopsy patients, 7 men and 3 women aged 41-80 years (mean 59.9 +/- 13.2 years), who died of rupture of the free wall of the left ventricle following acute MI. The site of rupture was examined histologically and the percentage areas of living myocytes, the processes of organization, necrosis and degeneration, and hemorrhage were compared in four patients who received thrombolytic therapy (group R) and six patients without thrombolytic therapy (group N). There were four pathological findings at the site of rupture: necrosis, neutrophil infiltration, hemorrhage, and evidence of the process of absorption. Group R consisted of two patients with hemorrhage, one with absorption, and one with unsuccessful reperfusion and neutrophilic infiltration. Group N included three patients with necrosis, two with neutrophilic infiltration, and one with hemorrhage. The percentage area involved by necrosis and degeneration was significantly lower in group R than in group N. Therefore, local stress produced by more surviving myocardium around the smaller necrosis area and the weakness of myocardium due to hemorrhage and absorption may provoke cardiac rupture in acute MI patients receiving thrombolytic agent.
BACKGROUND/AIM: Although the role of preoperative percutaneous transhepatic biliary drainage in obstructive jaundice has been the subject of controversy in many other countries, in Japan, almost all surgeons agree that biliary decompression should be performed prior to the surgical treatment in obstructive jaundice. This study was performed in order to determine the role of preoperative percutaneous transhepatic biliary drainage in obstructive jaundice. PATIENTS AND METHODS: We evaluated 238 patients with preoperative obstructive jaundice, and also studied its pathophysiology in experimental animal models. RESULTS: Both of these studies demonstrated that this procedure should be performed if the value of total bilirubin is more than 5 mg/dl, the ICG Rmax value of the future remnant liver is less than 0.4 mg/kg/min, and the duration of jaundice is more than 3 weeks. Preoperative biliary drainage improves the liver function, so that major operations can be safely performed without major complications. CONCLUSIONS: It therefore seems preferable that patients undergo preoperative biliary decompression to reduce serum total bilirubin to below 5 mg/dl, and to improve hepatic and reticuloendothelial functions and hepatic reserve prior to any major surgical operation.