Biomedical subjects

Y Akimoto

Publications and source records attributed to Y Akimoto.

At least 91 records · Page 5Linked to original sources

PubMed1992

Nifedipine-resistant Ca(++)-induced contraction in tail artery of spontaneously hypertensive rats.

Nifedipine-resistant Ca(++)-induced contractions (NR-Ca(++)-contraction) were compared in the tail arteries from SHRs and WKYs (5 and 13 week old). NR-Ca(++)-contraction of tail artery was defined as follows: Ca(++)-induced contraction in the presence of norepinephrine (NE) (10(-5) M) or 5-hydroxytryptamine (5-HT) (10(-5) M) in Ca(++)-free medium containing EGTA (0.1 mM) and nifedipine (10(-6) M). NR-Ca(++)-contractions in arteries from 5 week old SHRs and WKYs were not different. In contrast, NR-Ca(++)-contractions in arteries from 13 week old SHRs were about 2-fold greater than in arteries from 13 week old WKYs. In arteries from 13 week old WKYs and SHRs, nitroglycerin (10(-5) M) significantly reduced the NR-Ca(++)-contraction in the presence of 5-HT but not in the presence of NE. The reduction was inhibited by the presence of methylene blue (3 x 10(-6) M). 8-Bromo-cGMP (10(-4) M) reduced significantly the NR-Ca(++)-contraction in the presence of 5-HT in arteries from 13 week old SHRs and WKYs. The present experiments clearly demonstrated that the NR-Ca(++)-contractions (both in the presence of NE and 5-HT) in 13 week old SHRs were significantly greater than those in arteries from 13 week old WKYs. These results suggest that in addition to an increase in voltage-operated Ca++ mobilization reported by others, an increase in NR-Ca++ mobilization may contribute to the development of hypertension in SHR.

Animals↗

PubMed1992

Ampicillin concentrations in human radicular granuloma following a single oral dose of bacampicillin.

Ampicillin concentrations in human serum and radicular granulomas of 42 patients were determined after a single oral dose of bacampicillin (equivalent to 500 mg of ampicillin). Although wide variations were found among both serum and radicular granuloma ampicillin concentrations, measurable concentrations were found in all cases. The mean peak ampicillin concentrations in serum and radicular granulomas occurred at identical times, 1.5 hours, and were 11.19 micrograms/mL (range, 1.30 to 21.00 micrograms/mL) and 5.12 micrograms/g (range, 0.50 to 10.50 micrograms/g), respectively. The mean radicular granuloma/serum ampicillin concentration ratio at the peak time was 0.42. Ampicillin concentrations in radicular granulomas exceeded most of the minimum inhibitory concentrations for bacteria commonly isolated from odontogenic infections.

Administration, Oral↗

PubMed1992

Cefaclor concentrations in human serum, gingiva, mandibular bone, and dental follicle following a single oral administration.

1. Cefaclor concentrations in human serum (n = 59), gingiva (n = 46), mandibular bone (n = 39), and dental follicle (n = 42) following a single oral administration of cefaclor (500 mg) were measured by the paper disk method. 2. The peak times of serum, gingiva, mandibular bone, and dental follicle were 1.5, 2, 2, and 1.5 hr, respectively. 3. The mean peak concentrations of serum, gingiva, mandibular bone, and dental follicle were 7.58 micrograms/ml, 3.71, 1.59 and 2.42 micrograms/g, respectively. 4. The concentration ratios of gingiva/serum, mandibular bone/serum, and dental follicle/serum at peak times of the tissues were 0.49, 0.18, and 0.32, respectively. 5. Mean cefaclor concentrations in gingiva, mandibular bone, and dental follicle at peak times exceeded MIC for 90% for clinically isolated strains of alpha-hemolytic Streptococci.

Administration, Oral↗

PubMed1992

Immunohistochemical study of basement membrane reconstruction by an epidermis-dermis recombination experiment using cultured chick embryonic skin: induction of tenascin.

The production of extracellular matrix components such as laminin, Type IV collagen, fibronectin, and tenascin during the formation of basement membrane in cultured epidermis-dermis recombinant skin of 13-day-old chick embryo was analyzed immunohistochemically. The epidermis and dermis were separated from each other by treatment with EDTA and/or dispase. The basal lamina of the basement membrane was thus removed from both epidermis and dermis. The isolated epidermis was overlaid onto the isolated dermis, i.e., recombined, and then cultured for 1-7 days in a chemically defined medium (BGJb) on a Millipore filter. Immunofluorescence labeling was used for light microscopy and HRP or colloidal gold labeling for electron microscopy. In specimens from 2-day cultures, positive sites of anti-laminin and anti-fibronectin reaction were observed light microscopically as patches which, at the electron microscopic level, corresponded to fragments of the basal lamina located immediately beneath and in the vicinity of the attachment plaques of the hemidesmosomes. The staining pattern became continuous 7 days after recombination. Fluorescence labeling of laminin and fibronectin appeared somewhat earlier than that of Type IV collagen and tenascin. All of the four components were found localized primarily in the basal lamina. Furthermore, fibronectin and tenascin were also distributed in the extracellular matrix of the dermis. The expression of tenascin, which does not exist in the basement membrane of 13-day-old intact embryonic skin, was induced in vitro. These results suggest that hemidesmosomes may play an important role in the reconstruction of the basement membrane and that various components of the basement membrane appeared at different times during the reconstruction.

Animals↗

PubMed1992

In vitro proliferative and differentiated responses of lymphoma cells to PHA and IL-4 in a patient with intermediate lymphocytic lymphoma.

We carried out in vitro B cell colony assays, with phytohemagglutinin-P (PHA-P) and IL-4, on B cells from one intermediate lymphocytic lymphoma (ILL) patient and four chronic lymphocytic leukemia (CLL) patients. Peripheral blood B cells from the ILL patient responded to PHA and IL-4, they proliferated, and differentiated into cells with plasmacytoid cell morphology. They lost the CD19 surface antigen after 10 day co-culture with PHA and IL-4. The bone marrow of this ILL patient contained atypical plasma cells with multiple nuclei. Peripheral blood B cells from the four CLL patients responded to PHA, but IL-4 did not increase PHA-induced B cell colony formation in these cells. The CLL cells did not differentiate into plasma cells, and they were clearly different from the ILL cells in morphology, as shown by scanning electron microscope examination. Since this study was performed on cells from only one ILL patient, further examination of cells from many patients might be necessary to confirm the difference between ILL and B cell-type CLL.

Antigens, Surface↗

PubMed1992

[Essential thrombocythemia that transformed to myelofibrosis after three years].

A 66-year-old man was presented with thrombocytosis in February, 1988. Laboratory examinations on admission revealed a white blood cell count of 17,700/microliters and a platelet count of 274.4 x 10(4)/microliters. Bone marrow aspirates showed an increase of megakaryocytes (1,294/microliters). There was no fibrosis or Ph1 chromosome. He was diagnosed as having essential thrombocythemia and was treated with thrombopheresis, carboquone and ranimustine (MCNU). Subsequently his platelet count was well controlled approximately for three years. He was readmitted because of pyrexia and left hypochondralgia in February 1991. Physical examination revealed hepatosplenomegaly. Peripheral blood revealed leukoerythroblastosis associated with the occurrence of tear drop cells. Bone marrow aspiration resulted in a dry tap and the biopsy specimen showed reticulin fibrosis. This is a fairly rare case of essential thrombocythemia that transformed to myelofibrosis.

Aged↗

PubMed1992

[Chronic myelomonocytic leukemia associated with translocation 1;7, marked platelet aggregation and cryofibrinogenemia: a case report].

A 64-year-old male was admitted in September 1989 with complaints of fever and muscular weakness in the extremities. A peripheral blood examination on admission revealed WBC 10,300/microliters (monocytes 32%), RBC 195 x 10(4)/microliters, Hb 7.9 g/dl, Plt 12.8 x 10(4)/microliters with trilineage dysplasia. Bone marrow biopsy was normoplastic marrow with 25.7% of monocytes including immature blasts. Cytochemical analysis of the monocytes showed positive for peroxidase and dual esterase staining. Chromosomal analysis of peripheral blood revealed 46, XY, -7, +der(1) t(1;7)(p11;p11). A diagnosis of chronic myelomonocytic leukemia was made. Hemostatic studies revealed cryofibrinogenemia, marked platelet aggregation on blood smear, hyperfibrinogenemia and a marked increase in maximal amplitude of thrombelastogram. Treatment with prednisolone and VP16, resulted in a reduction of peripheral monocytes and a disappearance of cryofibrinogen, marked platelet aggregation and a decrease in muscular weakness. Nine months after diagnosis he died of DIC, pneumonia, lung abscess and sepsis.

Chromosomes, Human, Pair 1↗

PubMed1991

Reconstruction of basement membrane in recombinants of epidermis and dermis of chick embryonic skin in vitro: an electron microscopic study.

The tarsometatarsal skin from 13-day-old chick embryos was treated with EDTA and/or Dispase to separate it into epidermis and dermis, and the basal lamina was removed. The isolated epidermis and dermis were then recombined and cultured on Millipore filters in a chemically defined medium (BGJb). Beginning at 3-4 days after recombination, short fragments of new basal lamina and subbasal dense plaque were formed along the epidermal basal cell outer surface immediately subjacent to hemidesmosomes. After 6-8 days of culture, fragments of the basal lamina started to fuse together and the lamina became progressively continuous. At the same time, anchoring fibrils were formed to attach to the basal lamina. The hemidesmosome formation preceded the basement membrane formation. When normal embryonic epidermis was recombined with retinol-pretreated dermis and cultured for 7 days in BGJb, short fragments of the basal lamina, the subbasal dense plaque, and anchoring fibrils were formed, but the basement membrane remained discontinuous with many interruptions in the interspace between hemidesmosomes. These results demonstrate that pretreatment of dermis with retinol causes the changes noted in the basement membrane.

Animals↗

PubMed1991

Leaching of polychlorinated dibenzo-p-dioxins and dibenzofurans in fly ash from municipal solid waste incinerators to a water system.

In order to predict how much polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) are leached from fly ash by rain water when fly ash is disposed, leaching of PCDDs/Fs from a fly ash obtained from a municipal solid waste incinerator (MSWI) was investigated by packing the ash in a column and eluting with water. In the beginning of the elution, PCDDs/Fs associated with water-soluble particulates in the ash were eluted, whereas in the latter half, those associated with water slightly soluble particles were eluted, judging from the comparison of PCDDs/Fs in eluate fractions with those transferred to solutions from the original ash by stepwise batch methods with water and 2N hydrochloric acid. The amounts of PCDDs/Fs eluted from the ash column were 2.9% and 1.7% of those extracted from the original ash, respectively, while large amounts of PCDDs/Fs were contained in the fly ash in the column after the elution, suggesting that PCDDs/Fs in water-insoluble particulates of the ash would not be eluted by water.

Benzofurans↗

PubMed1991

Stimulation by Bt2cAMP of epidermal mucous metaplasia in retinol-pretreated chick embryonic cultured skin, and its inhibition by herbimycin A, an inhibitor for protein-tyrosine kinase.

Epidermal mucous metaplasia of cultured 13-day-old chick embryonic tarsometatarsal skin can be induced by culture in medium containing retinol (20 microM) for only 8-24 h and then in a chemically defined medium without vitamins or serum for 6 days. In the induction of mucous metaplasia, retinol primarily affects the dermal cells and a signal(s) induced in the dermis by excess retinol alters epidermal differentiation toward secretory epithelium. In this work we found that Bt2cAMP (2 mM) stimulated mucous metaplasia severalfold when added to retinol-pretreated skin but inhibited epidermal mucous metaplasia when added together with retinol. Forskolin (100 microM), an activator of adenylate cyclase, also stimulated mucous metaplasia when added to retinol-pretreated skin. On the other hand, transduction in the epidermal cells of a signal(s) induced in dermal cells by excess retinol was inhibited by herbimycin A (500 ng/ml), an inhibitor of protein-tyrosine kinases, and TPA (0.1 microM), an activator of protein kinase C. Hence these findings indicated that cAMP stimulated signal-induced mucous metaplasia, and that transduction of the signal(s) in the epidermal cells required protein-tyrosine kinase and was inhibited by protein kinase C.

Adenylyl Cyclases↗

PubMed1991

Vasoinhibitory effect of NP-252, a new dihydropyridine derivative, in canine cerebral artery.

The vasoinhibitory effect of NP-252, a 1,4-dihydropyridine derivative Ca++ antagonist, was examined in canine cerebral artery, and this effect was compared with that of nifedipine. NP-252 (10(-7)M) and nifedipine (10(-6) M) nearly abolished the contraction induced by addition of Ca++ to Ca(++)-free medium containing KC1. NP-252 (10(-6)M) and nifedipine (10(-6)M) attenuated the contraction produced by thromboxane A2 agonist (STA2) in normal medium, and the resultant contractions were 22% (n = 6) and 35% (n = 6) of the control contraction, respectively. The vasoinhibitory effects of NP-252 were significantly stronger than those of nifedipine in canine cerebral artery. NP-252 (10(-7) and 10(-6) M) dose-dependently attenuated nifedipine-resistant Ca(++)-contraction in the presence of STA2 in both canine cerebral and coronary arteries. The inhibitory effect of combined treatment with NP-252 (10(-6) M) and nitroglycerin (10(-6) M) on nifedipine-resistant Ca(++)-contraction in the cerebral artery was additive. These results indicate that NP-252 possesses a stronger vasoinhibitory effect than that of nifedipine in canine cerebral artery.

Animals↗

PubMed1991

Ampicillin concentrations in human oral tissues following a single oral administration of lenampicillin.

1. Ampicillin concentrations in serum (n = 20), gingiva (n = 12), jawbone (n = 13), dental follicle (n = 12), radicular granuloma (n = 2) and radicular cyst (n = 2) were measured in specimens obtained during 0.5-2.5 hr after a single oral administration of lenampicillin (equivalent to 500 mg of ampicillin). 2. Measurable ampicillin concentrations were found in all serum and tissues. 3. Ampicillin concentrations in serum and tissues except for some gingiva and jawbone exceeded MIC for 90% of clinically isolated strains of alpha-hemolytic Streptococci. 4. Ampicillin concentrations in gingiva and jawbone were below the MIC for 90% in 2 out of 12 and 4 out of 13 specimens, respectively.

Adult↗

PubMed1991

Effects of a new benzimidazole derivative, NC-1300-O-3, on gastric secretion and gastroduodenal lesions in rats.

We examined the effects of a new compound, NC-1300-O-3 (2-[2-N-methyl-N-(2-methylpropyl) amino] benzylsulfinyl benzimidazole), on the gastric mucosal proton pump (H+, K(+)-ATPase) activity, gastric secretion and gastroduodenal lesions in rats. The compound potently inhibited the enzyme activity in a concentration-dependent manner, the IC50 being 5.3 x 10(-6) M at pH 6.0 and 1.4 x 10(-5) M at pH 7.4. NC-1300-O-3 markedly and persistently (for more than 24 hr) inhibited basal gastric secretion in male or female animals when administered by the p.o. route. The compound also significantly inhibited gastric secretion by the intraduodenal (i.d.), intragastric (after pylorus ligation) and i.p. routes, but only weakly by the s.c. route. Repeated p.o. administration of the compound for 1 week also significantly inhibited gastric secretion. Histamine-stimulated gastric secretion was also significantly inhibited by the i.d. administration of the compound. NC-1300-O-3, administered p.o., potently prevented water-immersion stress-, histamine-, indomethacin-, prednisolone- and compound 48/80-induced gastric lesions. In addition, it also significantly prevented the formation of gastric lesions induced by various necrotizing agents. Mepirizole- and cysteamine-induced duodenal ulcers were also prevented by the compound. The antisecretory and antilesion activities of NC-1300-O-3, administrated p.o., were not altered on its combination with 2% NaHCO3.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1991

Gingival hyperplasia induced by nifedipine.

We describe 4 cases of gingival hyperplasia induced by nifedipine, together with clinical and histological findings. Hyperplasia of the interdental papillae was observed in all cases. Histologic examination showed multilayered epithelial parakeratosis with variations in the width, proliferation, reticulation and elongation of the rete pegs. Substitution of another drug and improvement of oral hygiene led to reduction of the gingival overgrowth without gingivectomy. These treatments are essential for gingival hyperplasia induced by nifedipine.

Aged↗

PubMed1991

[Clinical investigation on acute respiratory failure in patients with severe hematologic malignancy].

Ten patients with severe hematologic malignancies (four with acute leukemia, three with multiple myeloma, one with prolymphocytic leukemia, one with malignant lymphoma and one with blastic crisis of chronic myelogenous leukemia) developed respiratory failure during the period between April 1986 and May 1990. Clinically, the patients manifested high-fever, dyspnea refractory to oxygen therapy, diffuse pulmonary rales and severe hypoxemia without evidence of cardiogenic pulmonary edema. Chest roentgenograms displayed diffuse alveolar infiltrates. Respiratory failure occurred as early as 48 hours and as late as 66 days after the administration of intensive anti-neoplastic chemotherapy. At that time leukocyte count was between 100/microliters and 54,900/microliters. Marked leukocytosis was observed in two patients with AML and PLL. Respiratory failure was preceded by sepsis in one patient with AML and by pneumonia in nine patients. DIC was diagnosed in four patients. All patients treated with high dose methyl prednisolone (mPSL) within 12 hours after the onset of respiratory failure. Only one patient required assisted ventilation. High dose mPSL had significant effect on seven of ten patients. But three patients died from progressive respiratory failure, sepsis, pneumonia and multi-organ failure.

Acute Disease↗

PubMed1990

Intracellular accumulation of isoproterenol enhances the lactate production in the perfused rat heart.

Effects of intracellular accumulation of isoproterenol (ISO) on lactate production were examined in perfused rat heart. The lactate production during ISO perfusion in rat heart was increased and subsequent addition of an inhibitor of catechol-O-methyl transferase (COMT) further enhanced the production, and the enhanced production was significantly reduced by uptake2 inhibitor. The perfusion with ISO free-medium in the heart with high intracellular accumulation of ISO produced lactate more than that in the low intracellular accumulation. The present experiments demonstrated that the enhanced lactate production is accompanied by intracellular accumulation of ISO in the perfused rat heart, and suggested that the accumulated ISO may activate intracellular beta-adrenoceptors in the rat heart.

Animals↗

PubMed1990

Cephalexin concentrations in human serum, gingiva, and mandibular bone following a single oral administration.

1. Cephalexin concentrations in human serum, gingiva, and mandibular bone after a single oral administration of cephalexin (500 mg) were measured by the paper disc method. 2. The peak times of serum, gingiva, and mandibular bone were approximately 90, 120 and 120 min, respectively. 3. The peak concentrations of serum, gingiva, and mandibular bone were 10.58 micrograms/ml, 5.57 micrograms/g and 2.12 micrograms/g, respectively. 4. The concentration ratio of gingiva/serum and mandibular bone/serum peak time of serum were 0.47 and 0.18, respectively. 5. Cephalexin concentrations in gingiva and mandibular bond did not exceed the MIC80s for clinically isolated strains of Staphylococcus aureus spp., alpha-Streptococci and Peptostreptococcus spp.

Adolescent↗

PubMed1990

A novel orally active dopamine prodrug TA-870. III. Positive inotropic effect and cardiorenal selectivity in anesthetized dogs.

The effect of TA-870, a novel dopamine prodrug, on the cardiovascular system was studied in anesthetized open- and closed-chest dogs. Intraduodenal administration of less than or equal to 12 mg/kg TA-870 to anesthetized dogs increased left ventricular (LV) dP/dtmax and dP/dt/Pmax. Furthermore, at a lower dose of TA-870 (2 mg/kg), renal vascular resistance (RVR) decreased and renal blood flow (RBF) increased. Similarly, total peripheral resistance (TPR) decreased and cardiac output (CO) increased at less than 4 mg/kg. In an intravenous cumulative dose-response study of TA-870, the plasma-free-dopamine concentration was elevated depending on the dose of TA-870. Renal vasodilation occurred at a low plasma-free-dopamine concentration, whereas a positive inotropic action required higher plasma-free-dopamine. However, the dose-response curve for LVdP/dt/Pmax was steeper than that for RBF or CO. Heart rate was less affected than LVdP/dt/Pmax in open-chest dogs and decreased in closed-chest dogs. Propranolol strongly inhibited the effect of TA-870 on LVdP/dt/Pmax. It also inhibited the effects of TA-870 on TPR and CO to a lesser extent, and the remaining effects were almost completely inhibited by an additional treatment with the dopamine blocker, RS-sulpiride. In conclusion, TA-870 increased myocardial contractility and output by the enteral route, and the latter effect was produced at lower doses with the help of peripheral vasodilation due to the activation of dopamine receptors.

Anesthesia↗