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Biomedical subjects

Y Mishima

Publications and source records attributed to Y Mishima.

At least 271 records · Page 15Linked to original sources
PubMed1985

Congenital bile duct dilatation--possibly an hereditary condition.

A female patient underwent resection of a large choledochal cyst and hepaticojejunostomy when she was 11 years old at Tokyo Medical and Dental University Hospital. Her mother, 48 years old, also had congenital bile duct dilatation (CBD) with cancer. The mother had an anomalous pancreatico-biliary ductal junction. To investigate the possibility of a genetic link, family members of another three consecutive CBD cases were examined for bile duct dilatation and anomalous pancreatico-biliary junction. Endoscopic retrograde choledocho-pancreatography (ERCP) revealed an anomalous pancreatico-biliary ductal junction, without bile duct dilatation in the mother of a 17-year-old CBD patient. Two familial occurrences of CBD had been reported in the Japanese literature. Their combinations were; a father--a daughter and two sisters, respectively. Considering that the sex ratio of CBD is one male to 2.6 females, our results suggest that CBD or anomalous pancreatico-biliary ductal junction may be 1) an X-linked dominant trait or 2) autosomal dominant trait with relatively low penetrance in males. Since anomalous pancreatico-biliary ductal junction does not necessarily develop into bile duct dilatation, more familial investigations on pancreatico-biliary ductal junction and bile duct dilatation are essential to clarify the genetic contribution to CBD.

Adolescent↗
PubMed1985

Ribosomal RNA synthesis in mammalian cells permealized by diethylaminoethyl (DEAE)-dextran treatment.

Ehrlich ascites tumor cells were made permeable to nucleoside triphosphates by treating them with diethylaminoethyl (DEAE)-dextran. Permeable cells incorporated labeled UTP into RNA at a constant rate for at least 30 min at 37 degrees C and 100 min at 25 degrees C, whereas no incorporation was detected without DEAE-dextran treatment. This RNA synthesis is dependent on added nucleoside triphosphates and is affected differentially by different concentrations of alpha-amanitin. The results of both hybridization and S1-nuclease protection mapping experiments with pulse-labeled RNA synthesized in this system indicate that reinitiation of rRNA transcription takes place from the physiological initiation site in cells made permeable by treatment with DEAE-dextran. By using this system, we examined the kinetics of rRNA synthesis in mouse FM3A cells during inhibition of protein synthesis. The results reflected those previously obtained by analyses of nucleolar RNA synthesis in vivo during protein synthesis inhibition. This permeable cell system should provide a rapid and reproducible assay method for rRNA synthesis in mammalian cells.

Animals↗
PubMed1985

Analysis of tyrosinases as asparagin-linked oligosaccharides by concanavalin A lectin chromatography: appearance of new segment of tyrosinases in melanoma cells following interrupted melanogenesis induced by glycosylation inhibitors.

The structural alteration of carbohydrate moieties of tyrosinases associated with the depigmentation process induced by glycosylation inhibition has been investigated by using concanavalin A (Con A) affinity chromatography. Con A affinity chromatography of deoxycholate-solubilized large and small granule fractions shows that while all tyrosinases found in control B-16 cells exhibit affinity to Con A lectin, there is an emergence on non-Con A binding tyrosinases in the unpigmented cells induced by glycosylation inhibitors, such as tunicamycin and glucosamine. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, control tyrosinase activity forms 2 distinct bands consisting of T1 and T3. But tyrosinases from the unpigmented cells lose T3 tyrosinase and are resolved into a few different molecular weight components, one of which is Con A affinitive T1 tyrosinase and the others are non-Con A affinitive tyrosinases with smaller molecular weights than the T1 tyrosinase. These findings suggest that altered structures of carbohydrate moiety in tyrosinase molecules play a role in the induction of loss of membrane-binding capacity of tyrosinases, resulting in the loss of melanization in pigment cells.

Animals↗
PubMed1985

[Pharmacological studies of cinobufagin, in comparison with digitoxin].

General pharmacological properties of cinobufagin (CB), isolated from Senso, were compared with those of digitoxin (DT). Decrement of spontaneous movement, inhibition of writhing, prolongation of hexobarbital-induced hypnosis, muscle relaxation, inhibition of acetic acid-induced capillary permeability, hypothermia, antipyretic effect in mice; excitation of respiration in rabbits; nerve blocking action in the isolated sciatic nerve of frogs; cardiotonic effect in the isolated atria of guinea pigs; contraction of the isolated ileum of rabbits and guinea pigs; contraction of the aorta of guinea pigs; and relaxation of the isolated trachea of guinea pigs were common properties observed after separate application of CB and DT. Membrane stabilizing effect in erythrocytes of rats and inhibition of propulsive motility of the small intestine in mice were observed only after the application of CB. Inhibition of gastric juice secretion, antiinflammation on carrageenin- or dextran-induced edema, diuresis in rats, mydriasis in mice and potentiation of transmission in the neuromuscular junction of rats were observed only after the application of DT. After oral administration, the onset of the effects of CB (30 min) was faster than that of DT (3-4 hr), and the duration of the effects of CB (1-2 hr) was shorter than that of DT (greater than 24 hr).

Animals↗
PubMed1985

Acral lentiginous melanoma and its precursor--heterogeneity of palmo-plantar melanomas.

Malignant melanomas occur with high frequency in the volar skin and with heterogeneity consisting of acral lentiginous melanoma (ALM) and nodular melanoma in Japan. Analytical study has revealed the precursor of ALM which we designate plantar or palmar premalignant melanosis (PPM), and whose cellular characteristics appear to be similar to those of pagetoid premalignant melanosis or the radial phase of superficial spreading melanoma (SSM).

Foot Diseases↗
PubMed1985

[Control of melanogenesis by glycosylation inhibitors and the inhibitory effect of interferon on melanoma metastasis].

The Glycosylation inhibitors, glucosamine or tunicamycin induced a marked loss of pigment within melanoma cells in addition to their reduced metastatic ability. Electrophoresis of tyrosinase demonstrated the disappearance of or a marked decrease in membrane-bound tyrosinase, T3 in the small and large-granule fractions. Glycoprotein synthesis in the melanogenic subcellular compartments of pigment cells seems to play an integral role in melanogenesis which is principally enhanced in their carcinogenic status. The effect of interferon (IFN) on melanoma metastasis was investigated using B16-F10 melanoma cells. The inhibitory effect was maximal when given 3 h prior to tumor cell inoculation. IFN given 12 and 24 h prior to, as well as simultaneously with, tumor cell inoculation, also reduced metastases, but to a lesser extent. When given 2 h after the inoculation, no effect was shown. The salutary effect of IFN was abolished by anti-asialo GMI, but NK activity was enhanced equally throughout 3 to 24 hrs. This indicates that the effect is substantially dependent on NK cell activity, although the implication of other factors is not excluded.

Animals↗
PubMed1985

Comparison of hemodynamic effects of morphine, butorphanol, buprenorphine and pentazocine on ICU patients.

Morphine and narcotic agonist-antagonists have been used to assist ICU patients in adapting to mechanical ventilation. In this study, 10 mg of morphine and the equipotent doses of synthetic analgesics, 2 mg of butorphanol, 0.6 mg of buprenorphine or 30 mg of pentazocine were administered intravenously to 29 patients requiring a ventilator. Hemodynamic effects on the heart rate, mean arterial pressure (MAP), cardiac index, stroke index, left ventricular stroke work index, mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP) and systemic and pulmonary vascular resistance (PVR) were measured. The hemodynamic effects of the four drugs were mild and not statistically significant except for the reduction in PCWP and the increase in PVR after morphine and the increase in MAP and MPAP after pentazocine administration. These doses of the four drugs could be given safely even in critically ill patients. The hemodynamic effects of these analgesics showed a similarity between the administration of butorphanol and morphine, and between buprenorphine and pentazocine. This study demonstrates that morphine and butorphanol are preferred to the cases with hypertension, increased pulmonary arterial pressure or wedge pressure and that pentazocine and buprenorphine are more suitable for the cases with hypotension or hypovolemia.

Adult↗
PubMed1985

Longer survival and fewer metastases by levamisole and tegafur in 1, 2-dimethylhydrazine-induced murine colonic cancers.

The anticancer effects of levamisole, tegafur and their combination were experimentally compared in rats on the 1, 2-dimethylhydrazine (DMH)-induced colonic cancers. DMH at 20 mg/kg of body weight was injected subcutaneously to Donryu rats once a week for 24 weeks long. Nineteen weeks after the start of DMH administration, early colonic cancers were induced and, 28 weeks after, they developed into advanced cancers with distant metastases. From 19 weeks after the start of DMH injection, subcutaneous administration of levamisole at the dose of 2 mg/kg, oral administration of tegafur at 90 mg/kg and their combination were given to the rats daily for nine weeks. The animals were sacrificed 28 weeks after the start of DMH administration. Tegafur was effective, but levamisole with or without tegafur was not effective against early cancer. From 28 weeks after the start of DMH injection, levamisole, tegafur and their combination were administered to the rats daily for four weeks. All of the rats were necropsied when they died. The survival rate and mean survival days were significantly higher and longer in the levamisole groups than in the control rats (p less than 0.05). The incidence of distant metastases was also significantly lower in the levamisole groups than in the control group.

1,2-Dimethylhydrazine↗
PubMed1984

Purification of hamster melanoma tyrosinases and structural studies of their asparagine-linked sugar chains.

In cultured melanotic melanoma, a marked decrease of pigmentation has been found to be induced by the addition of tunicamycin [Y. Mishima and G. Imokawa (1983) J. Invest. Dermatol. 81, 106-114]. Since it appears that this impaired pigmentation arises from the loss of asparagine-linked sugar chains serving as a signal for transport of tyrosinase from GERL (Golgi-associated endoplasmic reticulum of lysosomes) to premelanosomes, tyrosinases from the membrane fraction of Greene's hamster melanoma have been purified, and the structures of their sugar chains have been analyzed. Two kinds of tyrosinases were purified by Triton X-100 solubilization; DEAE-cellulose, Sephadex G-200, and DEAE-Sephadex column chromatography; and preparative polyacrylamide gel electrophoresis. The two tyrosinases were separated by polyacrylamide gel electrophoresis, and both corresponded to Mr 69,000. Their asparagine-linked sugar chains were released by hydrazinolysis and analyzed. The sugar chains of the two tyrosinases were identical except for the sialic acid contents. One mole of each tyrosinase contained 1 mol of high-mannose-type sugar chains and 3 mol of complex-type sugar chains. The former chain has Man3 approximately 5 X GlcNAc2 and the latter has Man3 X GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc as their core structures. The complex-type sugar chains are composed of mono-, bi-, tri-, and tetraantennary sugar chains, with +/- Sia alpha 2----3Gal beta 1----4GlcNAc beta 1----as their outer chains.

Animals↗
PubMed1984

Different metastatic modes of malignant melanoma implanted in the ear of young and old mice.

An attempt has been made to determine (a) whether aging plays an important role in resistance against metastasis and (b) whether dithiothreitol, an effective in vitro mitogenic potentiator of splenic cells of young and old mice, can modulate the occurrence of pulmonary metastasis. B16-F10 melanoma cells were injected into the outer ear of young and old female C57BL/6 mice; and the growth of the primary tumor, the palpable size of the cervical lymph node, and the number of lung metastases were then determined at various intervals. The ear was amputated when the primary tumor reached 4 mm in mean diameter. The following results were obtained. (a) The growth rate of the primary tumor in young mice is comparable to that in old mice. (b) Enlargement of the cervical lymph node occurs earlier in old than in young mice. (c) Old mice are more vulnerable to pulmonary metastases, but small metastasized pulmonary colonies are more prominent in old than in young mice. (d) Dithiothreitol (100 micrograms) injected every 2 days after the inoculation of tumor cells is effective in reducing the incidence of pulmonary metastases in old mice.

Aging↗
PubMed1984

The 6S RNA transcribed from rodent total DNA in vitro is the transcript of the type 2 Alu family.

We have performed in vitro transcription, using total DNA isolated from mouse and a cloned mouse DNA fragment containing a representative type 2 Alu sequence characterized by Kominami et al. (1983) as templates. From each template, 6S RNA was transcribed. The fingerprint of the 6S RNA produced from in vitro transcription of total DNA showed a very clear pattern of oligonucleotides. By comparing the oligonucleotides of the 6S RNA produced from each template, we demonstrated that the 6S RNA transcribed from mouse total DNA is the in fact the transcript of type 2 Alu sequences. The composition of the oligonucleotides of the 6S RNA transcribed from mouse total DNA seems to reflect well that of the consensus sequence of the type 2 Alu family proposed by Krayev et al. (1982). In vitro transcripts of rat or hamster total DNA showed fingerprint patterns nearly identical to that of mouse DNA, confirming that rodents have equivalent type 2 Alu sequences whose transcripts have the same length and similar compositions of oligonucleotides. Thus total DNA transcription provides a novel approach to the detection and analysis of type 2 Alu sequences transcribed in vitro.

Animals↗
PubMed1984

Determination of the promoter region of mouse ribosomal RNA gene by an in vitro transcription system.

Sequences required for a faithful and efficient transcription of a cloned mouse ribosomal RNA gene (rDNA) are determined by testing a series of deletion mutants in an in vitro transcription system utilizing two kinds of mouse cellular extract. Deletion of sequences upstream of -40 or downstream of +52 causes only slight reduction in promoter activity as compared with the "wild-type" template. For upstream deletion mutants, the removal of a sequence between -40 and -35 causes a significant decrease in the capacity to direct efficient initiation. This decrease becomes more pronounced when the deletion reaches -32 and the sequence A-T-C-T-T-T, conserved among mouse, rat, and human rDNAs, is lost. Residual template activity is further reduced as more upstream sequence is deleted and finally becomes undetectable when the deletion is extended from -22 down to -17, corresponding to the loss of the conserved sequence T-A-T-T-G. As for downstream deletion mutants, the removal of the sequence downstream of +23 causes some (and further deletions up to +11 cause a more) serious decrease in template activity in vitro. These deletions involve other conserved sequences downstream of the transcription start site. However, the removal of the original transcription start site does not abolish the transcription initiation completely, provided that the whole upstream sequence is intact.

Cell-Free System↗
PubMed1984

Functional analysis of tyrosinase isozymes of cultured malignant melanoma cells during the recovery period following interrupted melanogenesis induced by glycosylation inhibitors.

Multiple forms of tyrosinase, T1, T2, T3, have been shown to differ with respect to carbohydrate moieties of these isozymes. We demonstrated that, in cultured B-16 melanoma cells, melanization can be completely interrupted by glycosylation inhibitors, such as glucosamine and tunicamycin, and that these inhibitors cause a selective loss of membrane-bound T3. It is further found that inhibition of melanization induced by glucosamine occurs even in the presence of protease inhibitors, such as phenylmethylsulfonyl fluoride and leupeptin, and that melanization inhibition is reversible upon removal of the inhibitor. In this report we have also examined the process of development and recovery of the tyrosinase isozymes in cells in which the interruption of melanogenesis has been released by the removal of these glycosylation inhibitors. The recovery process, which occurs during the period after interrupted melanogenesis and is a process of remelanization, has been biochemically followed. Tyrosinases obtained from the deoxycholate-solubilized large-granule fraction of these melanoma cells have been analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Immediately after removal (0 h recovery) of the glycosylation inhibitor, loss of melanization and T3 is accompanied by T1 heterogeneity which is visualized as two electrophoretically distinct species, T1' and T1''. At this time, T1' and T1'' do not have a concanavalin A affinitive carbohydrate moiety but do possess in vitro dopa reactivity. When recovery of melanization begins visibly 24 h later, T3 is re-formed with disappearance of T1 heterogeneity. By 48 h, the previous normal level of melanization is almost attained. These results suggest that maturation of tyrosinase may occur via T1' and T1'' as precursors of T3, or possibly T1 through the addition of N-glycosydically linked oligosaccharide moieties which can be interrupted by glucosamine and tunicamycin.

Animals↗