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Biomedical subjects

J Yoshida

Publications and source records attributed to J Yoshida.

At least 181 records · Page 10Linked to original sources
PubMed1998

Intracellular hyperthermia for cancer using magnetite cationic liposomes: an in vivo study.

The effect of hyperthermia on solid glioma tissue formed subcutaneously in the left femoral region of female F344 rats was investigated. Magnetite cationic liposomes (MCLs), which have a positive surface charge, were used as heating mediators for intracellular hyperthermia. MCLs were injected into the solid tumors, which were then subjected to irradiation by an alternating magnetic field (118 kHz, 384 Oe). The rats were divided into four groups, which received no irradiation (control: group I), or irradiation for 30 min given once (group II), twice (group III) or three times (group IV), and the hyperthermic effect on tumor growth was evaluated. Complete tumor regression was observed in 87.5% of the rats in group IV. In the other groups, tumors completely regressed in 20 and 60% of the rats in groups II and III, respectively. Histological observations showed that in group I tumors, MCLs were localized only around the point where they were injected, while in group II tumors they were a little more dispersed. In the cases of group III and IV tumors, however, the distribution of the MCLs was found to be widespread, and necrotic cells were observed throughout almost the entire tumor tissue. The high percentage of complete regression of group IV is considered to be due to this wide distribution of the MCLs. Furthermore, the treated rats showed no severe side-effects. These results suggest that our magnetic particles are potentially effective tools for the treatment of solid tumors.

Animals↗
PubMed1998

Antitumor immunity induction by intracellular hyperthermia using magnetite cationic liposomes.

Induction of antitumor immunity to T-9 rat glioma by intracellular hyperthermia using functional magnetic particles was investigated. Magnetite cationic liposomes (MCLs), which have a positive surface charge, were used as heating mediators for intracellular hyperthermia. Solid T-9 glioma tissues were formed subcutaneously on both femurs of female F344 rats, and MCLs were injected via a needle only into the left solid tumors (treatment side). The rats were then divided into two groups, which received no irradiation, or irradiation for 30 min given three times at 24-h intervals with an alternating magnetic field (118 kHz, 384 Oe). On the treatment side, the tumor tissue disappeared completely in many rats exposed to the magnetic field. The tumor tissue on the opposite side also disappeared completely, even though MCLs were not injected into the right solid tumors. To examine whether a long-lasting and tumor-specific immunity could be generated, the rats that had been cured by the hyperthermia treatment were rechallenged with T-9 cells 3 months later. After a period of transient growth, all tumors disappeared. Furthermore, immunocytochemical assay revealed that the immune response induced by the hyperthermia treatment was mediated by both CD8+ and CD4+ T cells and accompanied by a marked augmentation of tumor-selective cytotoxic T lymphocyte activity. These results suggest that our magnetic particles are potentially effective tools for hyperthermic treatment of solid tumors, because in addition to killing of the tumor cells by heat, a host immune response is induced.

Animals↗
PubMed1998

Complex cystic duct is associated with cholelithiasis.

The relationship between complex cystic ducts and cholelithiasis has seldom been investigated quantitatively. Thus we attempted a retrospective survey on two case series with and without cholelithiasis in a university hospital. A total of 500 patients who underwent endoscopic retrograde cholangiography were reviewed, 250 of whom had cholelithiasis and another 250 no gallstones. They were sampled at random during the period from 1979 through 1993. Parameters including the length, inner diameter and configuration of the cystic duct, and the angle formed by the cystic duct, and the axis of the gallbladder were compared between the groups with or without cholelithiasis. The patients with gallstones has significantly (p < 0.001) longer and narrower cystic ducts (a mean of 48 mm and 4 mm in length and diameter, respectively) than did those without stones (a mean of 28 mm and 7 mm, respectively). Moreover, patients with gallstones showed a significantly (p < 0.001) more acute angle between the gallbladder and the cystic duct than those without (a mean angle of 84 degrees and 119 degrees respectively). The overall frequency of the disfigurements of the cystic duct was significantly higher in the group with gallstones (99%) than in the group without (29%). The results therefore suggested that complex cystic ducts are associated with cholelithiasis.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1998

Inducible cyclooxygenase expression in canine basilar artery after experimental subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Inducible cyclooxygenase (COX-2) has been found to play a pathological role in cerebral insult. We investigated the expression of COX-2 in the basilar artery after experimental subarachnoid hemorrhage (SAH). METHODS: In a canine "two-hemorrhage" model of SAH, the basilar arteries were obtained on day 2 after a cisternal injection of autologous blood or on days 4, 6, 7, or 9 after the second injection. Basilar arteries also were obtained 12 hours after intracisternal injection a cytokine: interleukin (IL)-1 beta (0.03 microgram), IL-6 (3 micrograms), or IL-8 (10 micrograms). Western blotting with a polyclonal anti-COX-2 antibody was performed in these arteries. RESULTS: COX-2 protein was not demonstrated in the basilar artery in control animals without SAH. However, it was expressed in the basilar artery on days 2, 4, 6, and 7 after blood injection but not on day 9. Intracisternal injection of IL-1 beta, IL-6, or IL-8 also induced COX-2 in the basilar artery. CONCLUSIONS: COX-2 expression was detected in basilar arterial tissue in both acute and chronic stages after SAH. Elevation of inflammatory cytokines after SAH may be involved in the induction of COX-2, which may produce sufficient quantities of eicosanoids to affect hemodynamics after SAH.

Animals↗
PubMed1998

Primary peripheral lung carcinoma smaller than 1 cm in diameter.

BACKGROUND: Several investigators have reported on the risk of limited resection in patients with small peripheral lung cancer. Primary peripheral lung carcinomas 1 cm or less in maximum dimension were reviewed to study the feasibility of limited surgery. METHODS: Among 1,051 lung cancer patients who underwent surgical resection of the lung in the National Cancer Center Hospital East, Kashiwa, Chiba, Japan, from January 1986 through March 1997, there were 13 patients who had untreated peripheral cN0M0 tumors 1 cm or less in maximum dimension on the resected specimens who underwent systematic mediastinal dissection. Their specimens were histopathologically reviewed. RESULTS: There were ten adenocarcinomas, one small cell carcinoma, one poorly differentiated squamous cell carcinoma, and one typical carcinoid tumor. One adenocarcinoma showed lymphatic vessel invasion, venous invasion, and a subcarinal node metastasis. The small cell carcinoma was accompanied by a lymph node metastasis in a segmental node. The small cell carcinoma and another adenocarcinoma showed lymphatic vessel invasion. Of the ten adenocarcinomas, six were Noguchi's type B and four were type C. CONCLUSION: Even among the pulmonary peripheral cancers smaller than 1 cm in diameter, more than one third showed an invasive nature. This fact must be considered in selecting limited resection in these patients. It is evident that tumor size alone cannot be an indicator for limited resection in lung cancer patients.

Adult↗
PubMed1998

Growth inhibition of experimental glioma by human interferon-beta superinduced by cationic liposomes entrapping polyinosilic:polycytidilic acid.

Intracellular production of human interferon-beta (HuIFN-beta) was enhanced in three glioma cell lines (U251-MG, U251-SP, and U251-NN) using modified superinduction with cationic liposomes containing polyinosilic:polycytidilic acid (polyI:polyC), initially given with cycloheximide, to decrease the toxicity due to polyI:polyC. Modified superinduction had a significantly (p < 0.02-0.0001) greater inhibitory effect on all three glioma cell lines, and less toxicity than superinduction. A pilot trial in experimental gliomas implanted into nude mice was also performed. Superinduction including intratumoral injection of cationic liposomes containing polyI:polyC resulted in growth inhibition of U251-NN tumors and eradication of U251-SP tumors. Weight gain in mice was not inhibited by modified superinduction. Cationic liposomes decreased drug toxicity, and may help to target tumor cells in the modified superinduction of endogenous HuIFN-beta production.

Animals↗
PubMed1998

Gene therapy of central nervous system tumors.

Recently, remarkable advances have been achieved in molecular and genetic researches of different kinds of general diseases, as well as in basic and clinical studies using gene therapy for central nervous system diseases. For brain tumors, clinical trials have been already started in more than 10 clinical protocols and more than 100 patients with malignant brain tumors. Nevertheless, there are still major issues that remain to be resolved for achieving better clinical results, such as delivery system of genetic material, regulatory methods of the intracellular expression of the transgene, antitumor efficacy, and tumor selectivity. In this paper, molecular genetic studies and the current state of gene therapy for neurological diseases, especially brain tumors, are described, and the future direction of this fascinating approach is discussed.

Animals↗
PubMed1998

Titanium aneurysm clips: mechanical characteristics and clinical trial.

Titanium clip is well documented to reduce the artifact observed in computed tomography (CT) or magnetic resonance (MR) imaging and improve the quality of these images. There are, however, some demerits based on metallic characteristics including large spring portions, lack of long and fenestration clips, and difficulties to produce. We examined the mechanical characteristics of Sugita titanium aneurysm clips (product of 6 aluminium-4 vanadium-titanium) and investigate the safety in clinical use and the imaging quality compared with those of cobalt (Co) alloy clips. On mechanical test, Sugita titanium clips showed no significant difference in closing force compared with the conventional Co alloy clips. The closing force reduced about 10% after 100 times repeated opening in titanium clips in contrast with no remarkable changes in Co alloy clips. Sixty-four patients with ruptured or unruptured cerebral aneurysms (total number of 71 aneurysms) were treated with Sugita titanium clips through the microsurgical technique. None of the unfavorable outcome occurred in related to the titanium clips. Neither clip dislocation nor deformation was experienced in this series during the follow-up period. The clip artifacts seen in CT and MR image were markedly reduced, however, MR angiography had less quality to resolve anatomical structures due to an existence of vessel gap. These results indicate that in spite of some disadvantages, Sugita titanium clips allow safe and beneficial use routinely in aneurysm surgery insofar as the complete clipping is obtained.

Biomechanical Phenomena↗
PubMed1998

Benign fibroosseous lesions involving the skull base, paranasal sinuses, and nasal cavity. Report of two cases.

The authors report two patients with benign fibroosseous lesions involving the center of the skull base: a 15-year-old boy with repetitive meningitis and pneumocephalus and a 11-year-old boy with nasal obstruction and headache. The clinical diagnoses were ossifying fibroma and aneurysmal bone cyst, respectively. Lesions in both patients extended to the nasal cavity, the sphenoid and posterior ethmoid sinuses, and the skull base, where the planum sphenoidale, the sella turcica, the upper two-thirds of the clivus, and the medial portion of the middle cranial base were involved. The lesions were totally removed using an anterior craniofacial approach. Characteristics of these lesions and the surgical approach are discussed.

Adolescent↗
PubMed1998

[Flow cytometric DNA analysis and MR imaging of salivary gland tumors].

We correlated the histopathology of 32 cases of salivary gland tumors with MR imaging and flow cytometric DNA analysis. All malignant tumors were invasive and/or had an ill-defined margin. Fifty-seven percent of the pleomorphic adenomas were shown as a high signal intensity area on T2 weighted images. Fifty-six percent of Warthin tumors were shown as a low or iso signal intensity area on T2 weighted images associated with the cystic portion. Sixty-seven percent of malignant tumors were characterized by DNA aneuploidy and/or a total percentage of the S-phase fraction plus the G2 + M fraction higher than 10%. It was less than 10% and the Ki-67 positive fraction was higher than 20% in all pleomorphic adenomas. The Ki-67 positive fraction was less than 20% in 78% of Warthin tumors. The histopathology of all malignant tumors, 86% of the pleomorphic adenomas, and 89% of Warthin tumors was correctly predicted by the combination of MR images and flow cytometry. We suggest that the MR images combined with flow cytometric analysis of fine needle aspiration-derived materials is useful in the pre-operative histopathologic diagnosis of salivary gland tumors.

Adenolymphoma↗
PubMed1998

[Thoracoscopic repair of diaphragmatic eventration sustained at knife injury: a case report].

A 46-year-old male taxi driver was stabbed onto the left chest while on duty. On arrival soon after, he was hemodynamically stable. Computed tomography showed omental prolapse into the left thorax through the diaphragm. On the 11th day, he underwent thoracoscopy revealing omental prolapse via a 3-cm rent in the left diaphragm, which was reduced manually. The diaphragmatic orifice was lifted and debrided with suturing using a stapling cutter. The post-operative course was uneventful. Finger palpation through the orifice enabled safe suturing of the left diaphragm facing the omentum, the colon, and the stomach, all of which may suffer iatrogenic injury.

Endoscopy↗
PubMed1998

Hepatolithiasis: outcome of cholangioscopic lithotomy and dilation of bile duct stricture.

BACKGROUND: Cholangioscopic lithotomy (CSL) for hepatolithiasis, a minimally invasive procedure, has a place in complicated or recurrent hepatolithiasis. CSL itself, however, carries inherent risk for recurrence. We analyzed follow-up data after CSL for primary or repeat hepatolithiasis to determine the frequency of recurrence. METHODS: This retrospective analysis includes 21 patients with hepatolithiasis admitted to the hospital from September 1992 to December 1995 who underwent CSL. Through a percutaneous biliary drainage route, cholangioscopy was inserted to remove calculi with basket forceps or electrohydraulic lithotripter. Stenotic ducts, defined as less than 2 mm in diameter, were dilated with silicone rubber stenting or a balloon dilator. RESULTS: Ten patients were treated for primary hepatolithiasis and 11 for repeat hepatolithiasis. Of the patients with primary hepatolithiasis, one died of complications and the other nine patients underwent complete lithotomy. Among 11 patients who had repeat hepatolithiasis, four had undergone hepatectomy for hepatolithiasis and two previous CSLs; 10 patients (91%) underwent complete lithotomy. During the follow-up, four (40%) of the 10 patients with biliary stenosis at the time of cholangioscopic treatment showed recurrent calculi, whereas all eight patients without stricture had uneventful courses. Of the 19 patients who underwent complete lithotomy, calculi recurred in four (21%), three cases of which recurred less than 1 year after CSL. CONCLUSIONS: Against hepatolithiasis of primary and postoperative repeat cases, CSL can allow complete lithotomy. The bile duct stricture, however, carries a high risk for recurrent calculi; hence, permanent relief of stricture is mandatory.

Adult↗
PubMed1998

[Non-small cell lung cancer metastatic to the stomach and the jejunum causing intussusception: a case report].

We report a case of lung cancer metastatic to the stomach and the jejunum. Adenocarcinoma of the lingula (T 4 N 2 M 0) was diagnosed in a 45-year-old man, who then underwent chemoradiotherapy. Bowel obstruction later developed due to jejunal metastasis. Another metastasis was detected in the stomach. Laparotomy revealed jejuno-jejuno-jejunal intussusception caused by the two lesions. The jejunal and gastric lesions were identified as metastatic large cell carcinoma arising from the lung. One month postoperatively, the patient died due to disease. The literature has demonstrated that large cell carcinoma of the lung tends to metastasizes. However, the complex bowel invagination and gastric metastasis seen in our case are rare.

Carcinoma, Non-Small-Cell Lung↗
PubMed1997

Effects of adrenomedullin on rat cerebral arterioles.

The effects of adrenomedullin on isolated rat intracerebral arterioles were investigated and compared with those of calcitonin gene-related peptide (CGRP) and amylin. Adrenomedullin produced dose-dependent vasodilation (maximum dilation 27.1 +/- 2.1% at 3 x 10(-7) M, median effective dose (EC50)) 1.6 x 10(-9) M). CGRP produced similar vasodilation (19.8 +/- 4.1%) at 10(-7) M with a lower EC50 of 2.8 x 10(-11) M. Amylin did not cause vasodilation at concentrations up to 10(-6) M. Adrenomedullin-induced vasodilation was significantly suppressed by CGRP-(8-37). These data suggest that adrenomedullin is a potent vasodilator for arterioles in the cerebral microcirculation that acts through CGRP receptors.

Adrenomedullin↗
PubMed1997

The prognosis of resected lung carcinoma associated with atypical adenomatous hyperplasia: a comparison of the prognosis of well-differentiated adenocarcinoma associated with atypical adenomatous hyperplasia and intrapulmonary metastasis.

BACKGROUND: Radiologically undetected intrapulmonary solitary nodules are sometimes found in the resected lung. When the main tumor is a well-differentiated (w/d) adenocarcinoma, especially a bronchioloalveolar carcinoma (BAC), it can be difficult to determine morphologically whether the intrapulmonary nodules are atypical adenomatous hyperplasia (AAH) or intrapulmonary metastasis (PM). The authors evaluated the accuracy of the differential diagnosis of these two lesions from the prognostic point of view. METHODS: A retrospective study was conducted of 1360 lung carcinoma patients who had undergone surgical resection. Differential diagnosis was made between AAH and PM based on the conventional histologic specimens. Their clinicopathologic features were also studied. Survival rates were compared between these two groups. RESULTS: AAH was found in 137 patients (10%) with resected lung carcinoma. The 5-year survival rates were 72.9% in Stage I, 60.6% in Stage II, 27.1% in Stage IIIA, 0% in Stage IIIB, and 0% in Stage IV. They were not significantly different from the figures for all patients in the corresponding pathologic stages. Seventy-six cases were diagnosed as w/d adenocarcinoma associated with AAH, whereas PM was found in 46 cases of w/d adenocarcinoma. The 5-year survival rates of AAH and PM differed significantly: 64.6% and 35.5%, respectively (P 0.0004). When a comparison was made between cases of pT1-2, N0 w/d adenocarcinoma, most of which were BAC, with PM (n = 22) and those with AAH (n = 52), the latter had significantly better survival (P = 0.0086). CONCLUSIONS: The prognosis of resected lung carcinoma was not affected by association with AAH. The significant difference in prognosis between AAH and PM in w/d adenocarcinoma, especially in BAC, indicates that their morphologic distinction was correctly made by conventional pathologic examination in most cases.

Adenocarcinoma↗