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Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 667 records · Page 37Linked to original sources
PubMed1994

A type II lateral dislocation of bilateral intact mandibular condyles with a proposed new classification.

Lateral displacement of the intact mandibular condyle is a rare entity, first described in detail and classified into two types (type I, type II) by Allen and Young in 1969. We experienced a rare case of type II lateral dislocation of the bilateral condyles with fracture of other parts of the mandible. It is reflected that delayed closed reduction gave an imperfect result, inducing ankylosis. Bilateral condylectomy with reconstruction of the head using costal cartilage was performed subsequently to improve arthropathy, with a 2-year satisfactory follow-up. A review of the literature shows that there are three types of type II lateral dislocations of the mandibular condyle, which are further related to the technical difficulty of reduction. We propose a new typing of type II lateral dislocations of the mandibular condyle. The clinical assessment for this condition is early reduction. Rather, open reduction is more definitive. However, unavoidable delay in reduction induces ankylosis of the joint, which sometimes necessitates condylectomy with or without arthroplasty.

Cartilage↗
PubMed1994

[Assessment of vascularity and permeability in brain tumor using SPECT and 99mTc-DTPA-human serum albumin in relation to 201Tl SPECT].

Single photon emission computed tomography (SPECT) using technetium-99m-DTPA-human serum albumin (99mTc-HSA-D) and thallium-201 chloride (201Tl) was simultaneously performed on 25 patients with brain tumors; 10 with brain metastasis, 8 with astrocytoma (Gr. 3) and 7 with meningioma. The early image was obtained 10 minutes after 99mTc-HSA-D (740 MBq) injection, and the delayed image was taken 5 hours after the injection. HSA-D index, based on the ratio of 99mTc-HSA-D uptake in the tumor versus the cortical area, was calculated on each image, and compared with Tl index (tumor/contralateral cerebrum ratio). HSA-D delayed index was significantly greater than HSA-D early index in all tumor types (p < 0.05 by the Wilcoxon ranked sign test). Linear correlation between HSA-D early index and HSA-D delayed index was significant in astrocytoma (Gr. 3) (p < 0.01) and meningioma (p < 0.001), and a linear correlation between HSA-D delayed index and Tl index was significant in astrocytoma (Gr. 3) (p < 0.05). It is concluded that HSA-D early index and delayed index could reflect tumor vascularity and permeability, respectively, and provide supplementary information for Tl index.

Adult↗
PubMed1994

[Acute monoblastic leukemia (M5a) with dysmegakaryocytopoiesis associated with t(16;21) (p11;q22)].

We report a 24-year-old woman who had acute monoblastic leukemia associated with t(16;21) (p11;q22). She was referred to our hospital in April 1992 because of high fever and hemorrhagic diathesis. Physical examination on admission showed no hepatosplenomegaly. The hemoglobin was 5.1g/dl, platelet count 1.7 x 10(4)/microliters, the white blood cell count 18,700/microliters. Bone marrow aspirate showed that 86% of nucleated cells were monoblasts which were positive for peroxidase and alpha-naphtyl butyrate esterase. She was diagnosed as having M5a. Dysmegakaryopoiesis, such as micromegakaryocytes and megakaryocytes with multiple small separated nuclei, was seen in the bone marrow. Chromosomal analysis revealed t(16;21). Complete remission was achieved after two courses of BHAC-DMP therapy, but dysmegakaryopoietic features remained. She relapsed in September 1992. Review of the literature and this patient indicate that acute nonlymphocytic leukemia with t(16;21) is associated with multilineage leukemic differentiation.

Adult↗
PubMed1994

[Cyclooxygenase in ooplasm is essential for early embryonal differentiation but not for successful fertilization in the mouse].

It has been known that inhibition of prostaglandin (PG) synthesis interferes with successful implantation. The present study dealt with the chronology in cyclooxygenase (COX) expression and the effects of inhibition in mouse oocytes in the perifertilization period. COX protein was detected in both oocytes and fertilized eggs whereas the mRNA was not found by a high sensitivity RT-PCR only in blastocysts. Oocytes which were sham operated or micro-injected with preabsorbed anti-COX monoclonal antibody (hPES01) or non-immune IgG were fertilized and developed to two-cell embryos, whereas hPES01 injected oocytes were fertilized but failed to differentiate (p < 0.05 chi 2-analysis). This inhibitory effect on early embryonal development of COX inhibition was also seen in indomethacin pre-cultured oocytes which were successfully fertilized but failed to develop further. We concluded that the COX gene which is one of the immediate early genes is not transcribed in the perifertilization period but the enzyme which remains in the cytoplasm and the presence of intact COX before fertilization are essential for early embryonal differentiation.

Animals↗
PubMed1994

[Comparison between diltiazem and nicardipine used during anesthesia for coronary revascularization].

The effects of diltiazem (0.1 mg.kg-1 + 3 micrograms.kg-1.min-1) and nicardipine (0.01 mg.kg-1 + 2 micrograms.kg-1.min-1) on circulatory parameters were compared in 30 patients with ischemic heart disease, who underwent coronary revascularization. These drugs were administered intravenously via a Swan-Ganz catheter after induction of fentanyl anesthesia. The group injected with diltiazem showed significant decreases in heart rate, mean arterial pressure, cardiac output, left ventricular stroke work and rate-pressure product. The group injected with nicardipine showed significant decreases in mean arterial pressure, systemic vascular resistance, rate-pressure product and pressure-rate quotient. There were significant differences between the two groups in cardiac output, stroke volume, systemic vascular resistance and left ventricular stroke work. The results suggest that diltiazem protects the ischemic heart by slight cardiac suppression and that nicardipine reduces afterload by marked vascular dilatation during anesthesia for coronary revascularization. Both Ca-channel blockers were demonstrated to be useful.

Aged↗
PubMed1994

Assessment of postischemic reperfusion and diamox activation test in stroke using 99mTc-ECD SPECT.

To evaluate the cerebral distribution of 99mTc-ethyl cysteinate dimer (99mTc-ECD) at blood flow levels beyond the normal range, we investigated postischemic reperfusion and acetazolamide (Diamox) activation test in stroke patients. The postischemic reperfusion was studied in 10 patients who showed a postischemic hyperperfusion area on other single photon emission computed tomography (SPECT) studies using N-isopropyl-rho-[123I]iodoamphetamine ([123I]IMP), 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO), or 133Xe. 99mTc-ECD SPECT demonstrated a hyperactive area in one case, an isoactive area in four, and a hypoactive area in five. Correlations with CT findings revealed hyperactive areas without any abnormality, isoactive areas with perifocal rim, perifocal edema, or diffuse cerebral edema, and hypoactive areas with an infarct core. The Diamox activation test was studied in eight other patients with atherothrombotic stroke, and a limitation in vasodilative capacity was classified into three grades: Gr. 0 (none to minimal), Gr. I (mild), and Gr. II (moderate). [123I]IMP SPECT showed Gr. II and limitation in all eight cases. However, 99mTc-ECD showed Gr. II in three cases and Gr. I in five, and 99mTc-HMPAO revealed Gr. II in two cases, Gr. I in three, and Gr. 0 in three. We suggest that a lack of retention of 99mTc-ECD in a postischemic reperfusion area indicates the severity of the initial brain damage. Although the limitation in vasodilative capacity under Diamox-activated conditions was underestimated using 99mTc-labeled CBF tracers as compared with [123I]IMP, a retention of 99mTc-ECD in the unaffected area with an increased CBF under Diamox activation could be relatively superior to 99mTc-HMPAO.

Acetazolamide↗
PubMed1994

High-density lipoprotein inhibits the production of platelet activating factor acetylhydrolase by HepG2 cells.

We previously demonstrated that HepG2 cells secrete platelet activating factor (PAF) acetylhydrolase, which is identical to human plasma PAF acetylhydrolase. PAF acetylhydrolase has been shown to be associated with high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs) in plasma, and lipoprotein environment affects the enzyme activity. We examined the effects of HDL and LDL on the production of PAF acetylhydrolase by HepG2 cells. These lipoproteins were treated with diisopropylfluorophosphate (DFP) to inhibit completely the endogenous PAF acetylhydrolase. PAF acetylhydrolase activity in the control medium conditioned for 24 hours was 37 +/- 2.6 pmol/mg cell protein/min (mean +/- SD, n = 3). DFP-treated HDL markedly inhibited the production of PAF acetylhydrolase by HepG2 cells in a concentration-dependent manner, and 100 micrograms/ml of HDL inhibited the production by 82%. DFP-treated LDL had a slight inhibitory effect. Sulfur 35-labeled methionine-labeled PAF acetylhydrolase had a molecular weight of about 43 kd. In the presence of 100 micrograms/ml DFP-treated HDL, the labeling of PAF acetylhydrolase was decreased both in conditioned medium and in cell homogenate (to 62% and 42% of control values, respectively). DFP-treated HDL did not affect PAF acetylhydrolase activity of conditioned medium when they were mixed immediately before the assay. However, when conditioned medium was incubated for 24 hours with HDL, PAF acetylhydrolase activity was inhibited to 78% of the control value. Analysis with gel filtration chromatography disclosed that incubation with HDL resulted in the transfer of the LDL-associated enzyme to HDL fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1993

[An improved method of preparation of autopsied human inflated-fixed whole lungs for radiologic-pathologic correlation].

Inflated-fixed lung specimens, prepared using polyethyleneglycol 400, the standard Heitzman method have the disadvantage of bad staining. The authors attempted to improve this short-coming using human autopsied lungs and evaluated both microscopical findings and the degree of specimen inflation. Fifty-five human autopsied whole lungs were examined. Forty-six lungs with cannulation through the main bronchus were distended with 20% formalin, after clamping the cannula for 15 minutes to six days, formalin in lungs was expelled by air at 10 cm H2O pressure, then fixed with fixative-fluid containing polyethyleneglycol 400, 95% ethyl-alcohol, 40% formalin and water mixed in a ratio of 10:5:2:3. In 9 lungs without cannulation, formalin was expelled manually. The degree of distension of 46 of the 55 cannulated specimens was satisfactory (score A: 42 specimens, score B: 4 specimens). In 9 specimens without cannulation, inflation was poor (Score C). Good or excellent staining was obtained in 29 specimens (Score A: 10 specimens, Score B: 19 specimens), but 3 specimens were not be improved (Score C). Both inflation and staining were good in 21 specimens. This new method, requiring cannulation in the main bronchus, inflated-fixation with 20% formalin and expulsion of formalin by air prior to the standard Heitzman method enables both high quality staining and radiographs of the inflated-fixed lung specimen.

Biopsy↗
PubMed1993

FT-IR studies on the triplet state of P680 in the photosystem II reaction center: triplet equilibrium within a chlorophyll dimer.

The structure and molecular interactions of the primary donor (P680) in the reaction center (D1-D2-cytochrome b-559 complex) of photosystem II (PS II) have been investigated by detecting light-induced FT-IR difference spectra upon the formation of its triplet state (3P680). The 3P680/P680 spectrum obtained was analyzed by comparing it with difference spectra between the ground and lowest triplet states of purified chlorophyll a (Chl) in organic solvents. The negative peaks at 1669 and 1707 cm-1 accompanied by the positive peaks at 1627 and 1659 cm-1 in the 3P680/P680 spectrum were assigned to the keto C = O stretching mode, and the appearance of these two pairs of bands indicated that P680 has a dimeric structure analogous to that of the bacterial primary donor. From the band positions of the keto and carbomethoxy C = O stretches, the hydrogen-bonding properties of these two Chl molecules were found to be asymmetrical; in one Chl molecule both the keto and carbomethoxy C = O groups form hydrogen bonds, while in the other Chl molecule the keto C = O is not hydrogen-bonded whereas the carbomethoxy C = O probably is hydrogen-bonded. The temperature dependence of the intensity ratios of the keto C = O bands revealed that the triplet state is equilibrated between the two Chl molecules with an energy gap of 8.4 +/- 0.7 meV. Most of the triplet population was found to be localized on one Chl molecule (86% at 80 K), in which both of the two C = O groups are hydrogen-bonded, that is probably attached to the D1 subunit. Considering the structure of the bacterial reaction center determined by X-ray crystallography and the sequence homology between the D1 and D2 subunits of PS II and the L and M subunits of bacteria, a model of the P680 structure and its interactions with apoproteins has been proposed.

Chlorophyll↗
PubMed1993

Recognition signal for the C-terminal processing protease of D1 precursor protein in the photosystem II reaction center. An analysis using synthetic oligopeptides.

Synthetic oligopeptides of different chain lengths of 11 to 38 amino acids, corresponding to the carboxyl-terminal sequence of D1 precursor protein of the photosystem II reaction center, were subjected to a proteolytic cleavage by a processing enzyme isolated from spinach, in order to analyze the recognition signal. Practically the same Km and Vmax values were obtained for the oligopeptides consisting of more than 19 amino acids; a decrease in affinity, without affecting the Vmax value, was observed for the peptide consisting of 16 amino acids; no detectable activity was found for the peptide with 11 amino acids. When Asp-342 (12th residue from C-terminus) was replaced with Asn, for the peptide consisting of 16 amino acids, the enzymatic activity was completely abolished. In contrast, replacing Asp-342 with Glu had little effect. The efficiency of these oligopeptides as a substrate mentioned above, together with their effectiveness as an inhibitor, clearly demonstrated that the negative charge on Asp-342 plays a crucial role in the recognition, i.e., binding and cleavage, of the substrate by the processing enzyme, and suggested that the carboxyl-terminal extension consisting of 9 amino acids, by itself is not important in the binding.

Amino Acid Sequence↗
PubMed1993

An immunohistochemical study of the c-erbB-2 oncogene product in intraductal mucin-hypersecreting neoplasms and in ductal cell carcinomas of the pancreas.

BACKGROUND: Intraductal mucin-hypersecreting neoplasm of the pancreas (IMHN) is a unique tumor that has a tendency to spread intraductally. The clinical outcome of IMHN generally is far better than that of pancreatic ductal cell carcinoma. Because of the presence of various cell atypia within the same tumor, it sometimes is difficult to make an accurate histopathologic diagnosis and, therefore, predict its biologic behavior. It has been shown that overexpression of c-erbB-2 protein in breast cancer with lymph node metastases is related to a poor prognosis. Overexpression of c-erbB-2 protein has been reported as an infrequent event in pancreatic ductal cell carcinoma, but little is known in the case of IMHN. METHODS: The expression of c-erbB-2 protein was immunohistochemically investigated in the formaldehyde-fixed, paraffin-embedded tissues of 17 cases of IMHN, and 14 cases of pancreatic ductal cell carcinoma (8 cases with lymph node metastasis), using polyclonal and monoclonal c-erbB-2(p185) antibodies by the avidin-biotin method. RESULTS: Both the polyclonal and monoclonal antibodies showed similar immunostaining for the c-erbB-2 product. Overexpression of the c-erbB-2 product was observed frequently in IMHN (13/17), especially in that with moderate- to high-grade cell atypia (12/12), whereas it was detected in only 1 of 14 cases of pancreatic ductal cell carcinoma (1/14). Among eight cases of pancreatic ductal cell carcinoma with lymph node metastases, overexpression of the c-erbB-2 product in metastatic lesions was detected in two, one of whose primary lesions also overexpressed the oncogene product. CONCLUSIONS: These observations suggest the genetic expression of c-erbB-2 is related to the pathogenesis of IMHN.

Adenocarcinoma, Mucinous↗
PubMed1993

Orientation and nearest neighbor analysis of psbI gene product in the photosystem II reaction center complex using bifunctional cross-linkers.

Two distinct cross-linked products containing psbI gene product were generated in the photosystem II reaction center complex from spinach by treatment with bifunctional reagents directed to amino groups. The first product, which was generated by a 3,3'-dithiobis(succinimidyl propionate) treatment, is deduced to be formed between the epsilon-amino group of Lys3 of the psbI gene product, and a side-chain amino group present on the stromal extension of the D2 protein. The CNBr cleavage analysis of the cross-linked product predicted that the amino group of the D2 protein engaged in the cross-linking is either one of the three lysine residues on the N-terminal fragment (from N-terminus to Met19) or the Lys268 on the 6th fragment (from Val248 to Met275). The second product, which was also generated on the stromal side by a 1,6-hexamethylene diisocyanate treatment preferentially in alkaline conditions, is predicted to be formed between the epsilon-amino group of Lys3 of the psbI gene product and the N-terminal alpha-amino group of the alpha-subunit of cytochrome b559.

Cross-Linking Reagents↗
PubMed1993

Opening of ATP-sensitive K+ channels responsible for adenosine A2 receptor-mediated vasodepression does not involve a pertussis toxin-sensitive G protein.

Whether the opening of ATP-sensitive K+ channels responsible for adenosine A2 receptor-mediated vasodepression involves a pertussis toxin (PTX)-sensitive G protein was investigated in pithed rats. Adenosine and levcromakalim were used as reference substances. The blood pressure of pithed rats was kept elevated with an i.v. infusion of methoxamine. 2-(1-Octynyl)-adenosine (YT-146; 0.1-10 micrograms/kg i.v.), a selective adenosine A2 receptor agonist, produced a dose-dependent and long-lasting decrease in mean blood pressure (MBP) scarcely affecting heart rate (HR). Levcromakalim (0.3-10 micrograms/kg per min i.v. for 20 min) produced a dose-dependent and slowly developing decrease in MBP. The vasodepressor effects of YT-146 and levcromakalim were antagonized by glibenclamide (20 mg/kg i.v.), a blocker of ATP-sensitive K+ channels; the ED50 values for YT-146 and levcromakalim both increased about 2.5-fold. In rats pretreated with PTX (10 micrograms/kg i.v.), in which vagally induced bradycardia was nearly abolished, the vasodepressor effects of YT-146 and levcromakalim were slightly enhanced. Adenosine (0.3-10 mg/kg per min i.v. for 1 min) produced a dose-dependent and long-lasting decrease in MBP accompanied by a transient decrease in HR. The vasodepressor effect of adenosine was antagonized by glibenclamide; the ED50 value for adenosine increased about 3.2-fold, but not after PTX pretreatment. In contrast, the transient bradycardia was antagonized by PTX pretreatment but not by glibenclamide. These results suggest that the opening of ATP-sensitive K+ channels in vascular smooth muscle following stimulation of adenosine A2 receptors by YT-146 and adenosine does not involve a PTX-sensitive G protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1993

Anti-CD9 monoclonal antibody elicits staurosporine inhibitable phosphatidylinositol 4,5-bisphosphate hydrolysis, phosphatidylinositol 3,4-bisphosphate synthesis, and protein-tyrosine phosphorylation in human platelets.

Phosphoinositide metabolism elicited by anti-CD9 monoclonal antibody, a well-characterized platelet activator, was studied using acetylsalicylic acid-treated human platelets. TP82, which is an anti-CD9 monoclonal antibody, induced classical phosphatidylinositol 4,5-bisphosphate hydrolysis, as monitored by intracellular Ca2+ mobilization and phosphatidic acid production, and synthesis of phosphatidylinositol 3,4-bisphosphate, which is a major component of newly-described 3-phosphorylated inositol phospholipids produced during platelet activation. These changes were severely inhibited by 1 microM staurosporine, a potent, though non-selective, protein kinase inhibitor, which also abolished TP82 induction of tyrosine phosphorylation of multiple platelet proteins. Protein-tyrosine phosphorylation appears necessary to initiate both the classical phosphoinositide turnover and synthesis of the newly-described 3-phosphorylated inositol phospholipids in anti-CD9 monoclonal antibody-induced platelet activation.

Alkaloids↗
PubMed1993

Low concentrations of sodium fluoride inhibit Ca2+ influx induced by receptor-mediated platelet activation.

Sodium fluoride (NaF) alone below the concentration of 10 mM had no effect on platelet intracellular Ca2+ ([Ca2+]i). When platelets were incubated with low concentrations of NaF (< 10 mM) prior to thrombin stimulation, the second phase of [Ca2+]i elevation which is attributable to Ca2+ influx was suppressed, while the initial rapid peak of [Ca2+]i which is attributable to internal Ca2+ release was unaffected. Ca2+ influx assessed by the addition of extracellular Ca2+ to cells preactivated by thrombin in the absence of extracellular Ca2+ was also inhibited by NaF in a dose-dependent manner. NaF was also effective in inhibiting thrombin- or U-46619-induced Mn2+ entry. This inhibitory effect of NaF on Ca2+ influx occurred after a lag of at least 30 s. However, Ca2+ influx induced by ionomycin-induced Ca2+ depletion or by thapsigargin, a Ca(2+)-ATPase inhibitor, was only partially suppressed by NaF treatment. It is suggested that Ca2+ entry induced by receptor-mediated activation is NaF-sensitive and that the depletion of Ca2+ storage sites by artificial procedures facilitates the opening of Ca2+ channels via NaF-insensitive pathways.

Blood Platelets↗
PubMed1993

Wheat germ agglutinin-induced intracellular calcium mobilization in human platelets: suppression by staurosporine and resistance to cyclic AMP inhibition.

The lectin wheat germ agglutinin (WGA) elicited a prompt and sharp increase in intracellular Ca2+ concentration in human platelets. The WGA-induced Ca2+ mobilization was markedly inhibited by a protein kinase inhibitor staurosporine, whereas Ca2+ mobilization by receptor-mediated agonists, including thrombin, platelet-activating factor, and arginine-vasopressin, was not. In contrast, the lectin-induced Ca2+ mobilization was resistant to cyclic AMP inhibition, compared with that induced by receptor-mediated agonists. These findings indicate that the mechanism of intracellular Ca2+ mobilization, or possibly phospholipase C activation, induced by WGA is different from that induced by receptor-mediated agonists in human platelets.

Alkaloids↗