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Biomedical subjects

M Uchida

Publications and source records attributed to M Uchida.

At least 271 records · Page 15Linked to original sources
PubMed1992

Vertical transmission of HTLV-1 in HTLV-1 carrier rat.

A female F344 rat was injected with 2.4 x 10(6) MT-2 cells intravenously at 3 and 4 weeks old, and was mated with a non-infected male rat at the 17th week after injection, when the dam rat contained HTLV-1 provirus in the peripheral blood mononuclear cells as determined by polymerase chain reaction. HTLV-1 provirus was detected in at least 2 out of 9 offspring. This system should be useful for studies on the routes and prevention of vertical transmission and on elimination of once-transmitted HTLV-1.

Animals↗
PubMed1992

Anaesthesia for cardiac surgery in children with nemaline myopathy.

Nemaline myopathy is a rare congenital myopathy associated with skeletal deformities and respiratory complications. Three children with nemaline myopathy who underwent cardiac surgery are described where the heart rate decreased during induction of anaesthesia and body temperature increased during or after the surgery. The anaesthetic implications in the management of patients with nemaline myopathy are discussed.

Anesthesia, General↗
PubMed1992

Platelet-activating factor (PAF) plays an important role in the immediate asthmatic response in guinea-pig by augmenting the response to histamine.

1. To investigate the role of platelet activating factor (PAF) in the immediate asthmatic response, we examined the bronchial reactivity to histamine after administration of PAF to guinea-pigs or antigen challenge to passively sensitized guinea-pigs. 2. A bolus injection of PAF (20-40 ng kg-1), which did not cause a significant increase in intrathoracic pressure (ITP), augmented the bronchial response to histamine almost 8 fold. This airway hyperreactivity was observed even 1 min after PAF treatment. 3. A subthreshold dose of antigen (0.01 mg kg-1, i.v.) also provoked hyperreactivity to histamine, which became significant 6 and 11 min after the antigen treatment. 4. The specific PAF-antagonists, SM-10661 and CV-6209 (i.v.) dose-dependently inhibited both PAF- and antigen-induced airway hyperreactivities to histamine. 5. These results suggest that PAF plays an important role in antigen-induced acute airway responses by augmenting the activities of spasmogens.

Anaphylaxis↗
PubMed1992

Localization of elastic fibers and elastin mRNA in the uvea of chick embryo.

The distribution of elastic fibers and elastin mRNA was studied in the uvea of 19-day-old chick embryos by light and electron microscopy and in situ hybridization techniques using a 35S-labeled RNA probe. Light and electron microscopic examination revealed that elastic fibers were present in the uveal portion of the ciliary body, but not in the posterior choroid. Electron microscopically, elastic fibers were also found in Bruch's membrane. Abundant amounts of elastin mRNA were strictly localized in the fibroblasts in the uveal portion of the ciliary body, and no elastin mRNA was found in any of the cells in the posterior choroid by in situ hybridization. Cultured uveal tissue obtained from the ciliary body was found to produce large amounts of tropoelastin as compared with cultured posterior choroid. Using V8 protease peptide mapping and Northern blot analysis, the tropoelastin and its mRNA produced by the ciliary body were identical to those produced by the smooth muscle cells in the aorta. The results suggest that elastin is synthesized in the ciliary body, acting as a supporting substance in this area.

Animals↗
PubMed1992

[Effects of ambroxol HCl on the guinea pig tracheal mucous secretion and the rat pulmonary surfactant secretion].

The effects of orally administered ambroxol HCl (ambroxol) on guinea pig tracheal mucous secretion and rat pulmonary surfactant secretion were investigated histologically and biochemically. Ambroxol significantly increased the number of active goblet cells in guinea pig tracheal epithelium and total mucopolysaccharide level. Moreover, ambroxol significantly increased the neutral mucopolysaccharide level and PAS-positive substance in the guinea pig tracheal submucosal glands. Ambroxol did not show a significant effect on the content of the total phosphatidylcholine in rat lung lavage fluid, while ambroxol significantly increased the ratio of disaturated phosphatidylcholine to total phosphatidylcholine. From these results, it is suggested that ambroxol increases both the tracheal mucous secretion, especially the neutral mucopolysaccharide, and pulmonary surfactant secretion and these effects reflect part of the expectorant mechanism of the drug.

Ambroxol↗
PubMed1992

Oblique sagittal magnetic resonance imaging visualizing vascular compression of the trigeminal or facial nerve.

An oblique sagittal magnetic resonance (MR) imaging method was developed to provide better visualization of vascular compression of nerves. The MR images of 12 patients with trigeminal neuralgia and 24 with hemifacial spasm were analyzed. The oblique sagittal views were obtained along the nerve identified by the axial view at an angle of 105 degrees between the line along the dorsal brain stem and the line along the margin of the pontomedullary junction (in patients with hemifacial spasm) or by the midsagittal view through the midpons (in patients with trigeminal neuralgia). The T1- and T2-weighted, proton-density, and/or gradient-echo MR images were evaluated to optimize imaging conditions. The oblique sagittal gradient-echo MR image most clearly visualized vascular compression of the nerves as high-intensity lines in six patients with trigeminal neuralgia, which was confirmed intraoperatively in four. Fifteen (75%) of 20 oblique sagittal gradient-echo MR images demonstrated vascular compression of the facial nerves in patients with hemifacial spasm; 12 of these were confirmed intraoperatively. The control study used 15 oblique sagittal gradient-echo MR images of nonaffected contralateral and normal sites. Four false-positive findings were found. Oblique sagittal gradient-echo MR images are a useful planning aid, allowing differential diagnosis prior to microvascular decompression in trigeminal neuralgia and hemifacial spasm.

Adult↗
PubMed1992

[A retrospective analysis of surgical operations on malignancies of the ear].

In the past 20 years from 1970 to 1990, 21 patients with malignancies of the ear were treated at Cancer Institute Hospital. The primary sites were the auricle and cartilaginous external auditory canal (group 1: n = 8), the bony external auditory canal (group 2: n = 6) and the middle ear (group 3:n = 7). In group 1, pathological types were squamous cell carcinoma in four patients and basal cell carcinoma in the other four patients. Seven patients were treated by surgery alone, and the remaining patient was treated by interstitial implant radiotherapy. No recurrence have been noted up to today in this group. In group 2, pathological types were squamous cell carcinoma in four patients and adenoid cystic carcinoma in the other two patients. All of the six patients underwent external canal resection or subtotal temporal resection. Two patients received postoperative radiotherapy. A five year survival rate of group 2 was 60%. In group 3, pathological types were squamous cell carcinoma in six patients and undifferentiated carcinoma in the remaining patient. Most of them underwent radical mastoidectomy followed by irradiation. However, all the patients died within two years after treatment. In group 2 and 3, cytodiagnosis was useful for early discovery. In group 2, temporomandibular joint seemed to be a key point in surgical treatment. In group 3, the combination of conservative surgery with radiotherapy was not a radical treatment. This suggested it necessary to perform subtotal temporal resection to treat malignancy of the middle ear.

Adult↗
PubMed1992

Androgen receptor in cirrhotic liver, adenomatous hyperplastic nodule and hepatocellular carcinoma in the human.

Androgen receptors (AR) were assayed for cirrhotic liver, adenomatous hyperplastic nodule (AHN), and hepatocellular carcinoma (HCC) which were removed by partial hepatic resection from five patients. There were three men and two women. Age ranged from 59 to 68 years. Underlying cirrhosis was macronodular in three and micronodular in two. AHN was present within HCC in two patients, but these two lesions were found in different lobes of the same liver in another two patients. Only AHN was seen in the last patient. ARs in the cytosol of cirrhotic liver ranged from nil to 12.8 fmol/mg of protein with the dissociation constant (Kd) of 3.2-20.3 x 10(-10) M. AHNs possessed ARs ranging from 4.0 to 27.6 fmol/mg of protein (Kd values, 7.4-21.0 x 10(-10) M. All HCC nodules had ARs ranging from 11.8 to 72.8 fml/mg of protein with Kd values of 5.3-27.1 x 10(-10) M. Thus, cytosolic AR concentrations were highest in HCC, lowest in cirrhotic liver, and intermediate in AHN. The present study seems to indicate that AHN may be a precancerous lesion and that androgen and its receptor play an important role in human hepatocarcinogenesis.

Aged↗
PubMed1992

[The use of a Swan-Ganz catheter with a fast-response thermistor for the measurement of right ventricular performance during anesthetic management of pheochromocytoma].

We used a Swan-Ganz catheter with a fast-response thermistor to measure the right ventricular ejection fraction (RVEF) during the anesthetic management of two patients with epinephrine-dominant pheochromocytomas. Pre-operatively, one patient received alpha adrenergic blocking agents (prazocine, doxazocine) to control the blood pressure but the other patient did not receive any agents. In the latter patient who did not receive alpha adrenergic blocking agents, right ventricular function was depressed post-operatively in the recovery room. The importance of preoperative preparation with alpha adrenergic blocking agents was confirmed by the reductions in RVEF and RVEDVI (right ventricular end-diastolic volume index) after resection of the tumor. Not only left heart monitoring but also right heart monitoring with RVEF and RVEDVI are recommended for the proper management of a patient with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1992

[Effects of Nd:YAG laser irradiation on ventricular myocardium in dogs using an artificial sapphire tip contact laser catheter].

To apply Nd:YAG laser irradiation through a new sapphire tip contact laser method to catheter ablation in treatment of tachy-arrhythmias, effects of laser irradiation on ventricular myocardium were investigated in 10 mongrel dogs. Nd:YAG lase (1064nm) discharges were delivered to different sites on the endomyocardium at power of 5, 10, 15, 20 or 25w with duration of 3, 5, or 10 seconds (sec.) respectively in closed beating hearts. Histopathologically, the lesion irradiated was clearly demarcated from the normal myocardium by the construction band necrosis zone. The depth of injured myocardium was less than 2mm with 3 sec. irradiations, with 5 sec. from 1 mm to 4 mm in proportion to power increase, with 10 sec. from 3mm to 8 mm in proportion to the power from 5w to 15w and could not be measured in cases of more than 20w irradiations. Although with every irradiation duration, the depth of injury increased in proportion to the power increase. With the same total energy, a longer time of irradiation produced deeper injury than a shorter time. This method makes it easier to keep the laser positioned to target than bare laser, and is suitable for use in catheter ablation.

Animals↗
PubMed1992

Therapeutic efficacy of latoconazole in formulations of clinical use on experimental dermatophytosis in guinea pigs.

Therapeutic efficacy of clinical dosage forms of latoconazole (NND-318, CAS 101530-10-3), related compound of ketene dithioacetals with an imidazole ring, was examined on two experimental tinea models: a recently developed tinea pedis model and a conventional tinea corporis model in guinea pigs. The efficacy of the dosage forms was estimated on the basis of the rate of fungus-positive skin cultures and/or the score of skin lesions, and was compared to the other antifungal agents, bifonazole, clotrimazole and tolnaftate. While these reference agents exhibited curative effect on the tinea corporis model, the tinea pedis model was considerably resistant to the therapeutic treatment of the agents. The cream preparation and solution of lactoconazole at concentrations of more than 0.25% were highly effective in either tinea models, and at concentrations of more than 1%, lactoconazole achieved complete mycological cure. These results suggest that 1% of lactonazole is an optimal concentration for clinical use.

Animals↗
PubMed1992

[Evaluation of repeated hepatic dearterialization combined with intra-arterial infusion chemotherapy of unresectable primary or secondary cancer of the liver].

Repeated hepatic dearterialization combined with intra-arterial infusion chemotherapy was performed in 29 patients with unresectable primary or secondary cancer of the liver. Partial Response (PR) was obtained in 4 cases (1 hepatocellular carcinoma and 3 gastric secondaries), when evaluated by measuring the regression rate radiologically. The most remarkable effect was found in those with metastases from gastric cancer. A satisfactory result was not obtained for hepatocellular carcinoma with liver cirrhosis because of frequent associated complications. A strategy to modulate the resistance of tumors to ischemia and anticancer drugs should be considered in order to obtain a better clinical result by this method.

Catheterization↗
PubMed1992

[Clinical pharmacology of anticancer agents [Part 5] Antimetabolites (2)].

III Purine antagonists Biosynthesis of guanine nucleotides has been reported to be up regulated in tumor cells. In guanine nucleotide synthesis, there are 2 rate-limiting enzymes, i.e. inosine monophosphate dehydrogenase for de novo synthesis and hypoxanthine guanine phosphoribosyltransferase for the salvage pathway. Therefore, agents acting on these 2 enzymes to inhibit guanine nucleotide synthesis could be expected to have a superior effect on tumor proliferation. The main antitumor agents belonging to this class are thiopurines [including 6-mercaptopurine (6 MP), 6-thioguanine (6 TG) and 6-thioinosine (TIR)], thiazofurin (TZF), and arabinofuranosylfluoroadenine (F-ara-A). In the activation of 6MP to its ribotide. PRPP is the rate limiting factor. After the ribotide is produced, it is metabolized to another active form by enzymes catalyzing purine nucleotide metabolism. The antitumor effect of TZF is enhanced by the combination of TZF with allopurinol, which increases the plasma hypoxanthine level and subsequently inhibits recovery of the reduced guanine nucleotide pool by TZF. F-ara-A induces DNA strand damage as well as inhibiting DNA synthesis and is expected to have a significant antitumor effect on slowly growing tumors. These agents are mainly effective for treating hematological malignancies. IV Antifolic agents Among the antifolates, methotrexate (MTX) is the most useful drug for both hematologic malignancies and solid tumors. MTX primarily inhibits one-carbon transfer through the inhibition of dihydrofolate reductase and thus blocks the biosynthesis of both purine and pyrimidine nucleotides. Formyl polyglutamate synthetase catalyzes folate to its polyglutamate, both the active and retention forms. It is also important as an activating enzyme as well as being a target of MTX. MTX directly inhibits thymidylate synthetase, which could be the main target during high-dose therapy. High-dose MTX therapy with leucovorin (LV) rescue is effective even for tumors which are resistant to conventional treatment. During clinical use, not only MTX levels but also those of its inactive metabolites [7-hydroxy-MTX and 2, 4-diamino-N10-methylpteroic acid(DAMPA)] should be monitored. High-dose MTX therapy with LV rescue requires precise monitoring and LV rescue should be continued until the MTX level falls below 5 x 10(-8) M. MTX is also known as the safest drug which can be directly administered to into the central nervous system. Many other antifolates are under development, among which trimetrexate might be the most promising. Studies on antimetabolites have developed side by side with research on nucleotide tumor cell metabolism, which has produced a number of the antitumor agents now available for cancer chemotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Antimetabolites, Antineoplastic↗
PubMed1992

[Five cases of hematological disorders associated with acute myocardial infarction in thrombocytopenia].

Case of hematological disorders associated with acute myocardial infarction had been found in five of forty five autopsy cases which had hematological disorders during the past seven years. The five cases of hematological disorders consisted of two cases of myelodysplastic syndrome, a case of aplastic anemia, a case of primary myelofibrosis in blast transformation, and a case of acute myelogenous leukemia. All the patients were over 60 years old. Four patients had coronary artery stenosis and extensive myocardial infarction. Fibrinogen degradation products were elevated in four patients. DIC was recognized in two and suspected in two others. In all cases, platelet counts markedly decreased to less than 2.5 x 10(10)/L. Since no chest pain was noted by any patient, it was difficult to diagnose acute myocardial infarction without autopsy, except in one case. It is important to recognize the possibility of severe cardiac dysfunction due to myocardial infarction in thrombocytopenia, especially in the aged with DIC.

Aged↗
PubMed1992

[Clinical pharmacology of anticancer agents (Part 4). Antimetabolites (1)].

1. Pharmacodynamics and pharmacokinetics of antimetabolites. Antimetabolites are administered in the form of a base or its riboside, which is incorporated into the cell and converted to an active or inactive metabolite. The active metabolite remain in the cell inhibiting the enzymes to catalyze nucleotide synthesis for nucleotide triphosphate formation, but the inactive metabolites are rapidly excreted out of the cell. The inhibitory effect of antimetabolites on nucleotide formation is correlated with factors, such as maintenance of drug blood level, incorporation of the drug into the cell, activation and inactivation of the drug, affinity of the active form to the corresponding enzyme, and change in pool size of the intermediate metabolites in nucleotide synthesis. The salvage synthesis occurring at the higher level of the enzymes catalyzing nucleotide synthesis to counteract the inhibition by the drug is also correlated with the nucleotide formation. II. Pyrimidine antagonists 1. Cytosine arabinoside (ara-C) and its derivatives Ara-C is rapidly converted to ara-CTP and ara-U. The former remains in the cell and inhibits DNA polymerase, but the latter is excreted rapidly out of the cell. A small portion of ara-C is incorporated into DNA, which results in the degradation of DNA as demonstrated by reduced sedimentation of bulk DNA in alkaline sucrose gradient centrifugation and the ladder DNA fragmentation with a minimum fragment of approximately 180 base pairs and its conjugates in agarose gel electrophoresis. Behenoyl ara-C (BHAC) is highly lipophilic and highly distributed in the erythrocyte stroma and membrane fraction of leukocytes after iv infusion. The incorporated BHAC is released after the plasma BHAC level decreases, which suggests that erythrocytes can be a drug reservoir after iv infusion. Therefore, severe anemia should be treated before BHAC chemotherapy for longer maintenance of the plasma BHAC level. 2. 5-Fluorouracil (5-FU) and its derivatives Activation of 5-FU in the cells is metabolized by uracil metabolizing enzymes to FUMP and FdUMP. FUMP is further metabolized to FdUMP and is also incorporated to RNA. FdUMP produces a ternary complex with thymidylate synthetase and leucovorin; subsequently, conversion of dUMP to dTMP is strongly inhibited. Thus, FUMP and FdUMP inhibit RNA and DNA metabolism, respectively. Enzyme activity during 5-FU metabolism and consequently the degree of inhibition of DNA and RNA syntheses markedly differ with the tumor cell species. This should be taken into consideration when performing chemotherapy of malignancies.

Animals↗
PubMed1991

Infection of rats with HTLV-1: a small-animal model for HTLV-1 carriers.

A human T-cell line producing human T-cell leukemia virus type I (HTLV-I), MT-2, was injected intravenously into female F344 rats aged 5 weeks to make HTLV-I carrier rats. Antibody against HTLV-I was detected at the 5th week after MT-2 injection, and its titer reached a high plateau which continued from the 15th to the 27th week. The antibodies were against p19, p24, p28 and p53 of HTLV-I antigens from MT-2 cells. The gag, pX and LTR nucleotide sequences of HTLV-I provirus were demonstrated by using polymerase chain reaction (PCR) in the peripheral-blood mononuclear cells of 3 rats at the 44th week and 2 at the 66th to 68th week out of 8 F344 rats injected with MT-2 cells. Quantification of the HTLV-I proviral sequence revealed that 30 to 60 molecules were present in 10(5) peripheral-blood mononuclear cells, indicating that the rats were chronically infected with HTLV-I. HTLV-I-infected rats could serve as a small-animal model for studying the pathophysiological state of HTLV-I carriers and also that of HTLV-I infection on various HTLV-I-related diseases, including adult T-cell leukemia and HTLV-I-associated myelopathy.

Animals↗