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Y Ishihara

Publications and source records attributed to Y Ishihara.

At least 145 records · Page 8Linked to original sources
PubMed1993

Continuous column culture system for adherent cells.

A new continuous column culture system for adherent cells was developed using beads. The beads were packed in a column and an appropriate medium was continuously passed through. The whole system was kept under closed conditions. L cells and C6 cells were cultured by this new system. The number of cells increased linearly up to 16 days and reached a maximum at around 18 days. As the heat production remained constant for 16 days, it can be concluded that cells grown in this system had identical characteristics. The final concentration of cells reached was 1.0 x 10(8) ml-1. The cells could grow both in the upward and the downward direction. Advantages of this system are: (1) Cells can be recovered in their adherent form on the beads; (2) cells can easily be collected from the column by trypsinization, and (3) cells remaining in the column after trypsinization can grow again.

Animals↗
PubMed1993

The pharmacokinetics of primaquine in calves after subcutaneous and intravenous administration.

The pharmacokinetics of primaquine was studied in calves of 180-300 kg live weight. Primaquine was injected at 0.29 mg/kg (0.51 mg/kg as primaquine diphosphate) intravenously (IV) or subcutaneously (SC) and the plasma concentrations of primaquine and its metabolite carboxyprimaquine were determined by high-performance liquid chromatography. The extrapolated concentration of primaquine at zero time after IV administration was 0.50 +/- 0.48 microgram/ml (mean +/- SD) which decreased with an elimination half-life of 0.16 +/- 0.07 h. Primaquine was rapidly converted to carboxyprimaquine after either route of administration. The peak concentration of carboxyprimaquine was 0.50 +/- 0.08 microgram/ml at 1.67 +/- 0.15 h after IV administration. The corresponding value was 0.47 +/- 0.07 micrograms/ml at 5.05 +/- 1.20 h after SC administration. The elimination half-lives of carboxyprimaquine after IV and SC administration were 15.06 +/- 0.99 and 12.26 +/- 3.06 h, respectively. The areas under the concentration-time curve for carboxyprimaquine were similar following either IV or SC administration of primaquine; the values were 11.85 +/- 2.62 micrograms.h/ml after the former and 10.95 +/- 2.65 micrograms.h/ml after the latter. The mean area under the concentration-time curve for primaquine was less than 0.1 micrograms.h/ml after either route of administration.

Animals↗
PubMed1993

Enhanced proliferation of fetal rat hepatocytes in primary culture induced by ritodrine.

OBJECTIVE: Although ritodrine crosses the placenta, its direct effect on fetal cell proliferation has not been reported. We hypothesized that beta 2-adrenergic receptor stimulation could promote fetal liver growth. STUDY DESIGN: Ritodrine was added to serum- and hormone-free primary cultures of fetal, neonatal, or adult rat hepatocytes. We measured both tritiated thymidine incorporation into deoxyribonucleic acid and nucleus number. The effect of ritodrine on cell cycle was also analyzed with flow cytometry. RESULTS: Ritodrine enhanced the proliferation of fetal rat hepatocytes. Ritodrine remarkably stimulated deoxyribonucleic acid synthesis of fetal and neonatal but not adult hepatocytes. The effect was dose dependent and was antagonized by propranolol. Analysis of the nuclear deoxyribonucleic acid content derived from flow cytometry revealed that cells stimulated by ritodrine entered S phase. CONCLUSION: These results indicate that ritodrine may promote the proliferation of fetal hepatocytes through the stimulation of beta 2-adrenergic receptors, followed by induction of deoxyribonucleic acid synthesis.

Animals↗
PubMed1993

Elevation of amniotic fluid interleukin 6 (IL-6), IL-8 and granulocyte colony stimulating factor (G-CSF) in term and preterm parturition.

We determined the levels of inflammatory cytokines such as interleukin 6 (IL-6) granulocyte-colony stimulating factor (G-CSF) and IL-8 in the amniotic fluids from women with premature or term delivery. Cytokines were detectable even in the absence of apparent infection (group 1), but much higher cytokine levels were found in cases of intrauterine infection, particularly in cases of premature delivery (group 2). In cases of term delivery (groups 3-5), all of the cytokine levels showed c. 3- to 4-fold increase during labor pain (group 4) and an 8- to 13-fold increase in the presence of endotoxin (group 5), in comparison with the levels in cases where neither factor was present (group 3). Regarding infection, the cytokine levels were 20- to 30-fold higher in chorioamnionitis-positive premature delivery group (group 2), than in the infection-negative group (group 1). All the cytokines were simultaneously induced in amniotic fluid by labor pain and infection, and a significant positive correlation was observed among these three cytokine levels. In-vitro culture system and immunohistochemical study indicated that the cytokines in the amniotic fluid appeared to originate from trophoblasts and decidual cells. Thus, infection and labor pain may trigger the production of inflammatory cytokines at term as well as premature delivery and the determination of these cytokine levels will be a good indication for the prediction of the presence of intrauterine infection.

Amniotic Fluid↗
PubMed1993

Host-specific hemagglutination of influenza A (H1N1) virus.

H1N1 strains of influenza A virus isolated during the influenza season of 1991-92 were divided into two groups according to the property of host-specific hemagglutination. Group 1 viruses agglutinated human and chicken red blood cells. Group 2 viruses agglutinated human but not chicken red blood cells. The viruses of both groups, however, showed the same antigenic structure determined with ferret antisera. The virus clones which were plaque-purified twice from a group 2 virus retained the characteristic of host-specific hemagglutination after five successive passages in MDCK cells, indicating that this phenomenon is genetically determined. However, the amino acid sequences of the hemagglutinin (HA) polypeptides deduced from the nucleotide sequences of the HA gene of the two groups did not show any differences between them. This suggests a difference in amino acids in some other polypeptide(s), which affects the host-specific hemagglutination.

Amino Acid Sequence↗
PubMed1993

Detection of early lesions of "ungual" malignant melanoma.

BACKGROUND: The nail area is commonly affected by malignant melanoma. The prognosis of malignant melanoma of the nail is poor, because at the time of diagnosis most lesions are in the advanced stage. Correct diagnosis of early lesions could improve the prognosis. METHODS: For 3 years, all patients with nail pigmentation at the dermatology clinic were screened for five specific criteria for the diagnosis of early lesions of malignant melanoma. Histologic examination was performed on 10 of 29 lesions. RESULTS: Five of the 29 lesions were advanced malignant melanoma, easily diagnosed clinically. Two of the remaining 24 lesions fulfilled most of our clinical criteria of early malignant melanoma of the nail apparatus; that is, they appeared as melanonychia striata during adulthood, were wide in breadth measuring 9 and 11 mm, and showed variegated shades of brown. Periungual pigmented macule (Hutchinson's sign) was observed in one of the two cases. Total resection of the lesions was performed, followed by skin grafting. CONCLUSIONS: Histologically, an increased number of atypical melanocytes, mainly arranged as solitary units, were observed only in the epithelia of the nail matrix and of the nail-bed, confirming that these lesions were "ungual" malignant melanoma in situ. Such an early lesion of malignant melanoma of the nail apparatus can be completely cured with conservative excision, and the phalanx of the affected digit can be preserved.

Adolescent↗
PubMed1993

Effective detection of plantar malignant melanoma.

BACKGROUND: As the sole of the foot is the most prevalent site of malignant melanoma in non-Caucasians, early detection of the neoplasm at this anatomical site is very important. In our previous study, we proposed a clinical guideline that acquired melanocytic lesions on the sole larger than 7 mm in maximum diameter should be examined histologically. METHODS: Eighty-one Japanese patients with the complaint of plantar pigmented lesions were screened at our dermatology clinic during 3 years using the 7-mm criterion. RESULTS: Of the total 80 melanocytic lesions on the sole, 14 lesions were larger than 7 mm in maximum diameter, excluding congenital lesions. Diagnoses of the 14 "large" lesions were as follows: advanced malignant melanoma, 8 lesions; early malignant melanoma (malignant melanoma in situ), 1 lesion; acquired melanocytic nevus, 4 lesions, and volar melanotic macule, 1 lesion. CONCLUSIONS: The present study confirmed the validity of the 7-mm criterion for the early effective detection of plantar malignant melanoma.

Adolescent↗
PubMed1993

[Application of PCR for isolation of Chlamydia pneumoniae].

Chlamydia pneumoniae was isolated from the throat swab of a 5-year-old girl with acute bronchitis. The titers of IgM and IgG antibodies to C. pneumoniae in the serum were 1:20 and 1:2560, respectively. C. pneumoniae genome was detected by polymerase chain reaction in the throat swab and the infected cells after three passages, while C. pneumoniae was isolated from the throat swab after five passages by cell culture. PCR is considered to be a helpful method to isolate C. pneumoniae efficiently in routine cell-cultures.

Acute Disease↗
PubMed1993

Prevalence of newly isolated, cytopathic small round virus (Aichi strain) in Japan.

Cytopathic small round virus (Aichi strain), isolated from a patient with oyster-associated gastroenteritis, showed no reaction in the polymerase chain reaction method for enteroviruses or in the enzyme-linked immunosorbent assay (ELISA) for the five serotypes of astroviruses. Our ELISA was sensitive in detecting the Aichi strain antigen in stool samples, but there was no reaction in this ELISA with any non-Aichi strains of enteric viruses, with such origins as enterovirus, rotavirus, Norwalk virus, calicivirus, or astrovirus. In the ELISA, 13 of 47 stool samples from adult patients in five of nine oyster-associated gastroenteritis outbreaks were positive, but only 1 of 397 pediatric stool samples in Aichi Prefecture was positive. The prevalence rate for Aichi strain antibody was found to be 7.2% for persons aged 7 months to 4 years. The prevalence rate for antibody to Aichi strain increased with age, to about 80% in persons 35 years old. On the basis of the results of the present study, it was hypothesized that Aichi strain could be a new type of small round virus that mainly produces diarrhea in patients in the 15- to 34-year-old age group, 50 to 76% of whom possess neutralizing antibody.

Adolescent↗
PubMed1993

Central cholinergic agents. IV. Synthesis and acetylcholinesterase inhibitory activities of omega-[N-ethyl-N-(phenylmethyl)amino]-1-phenyl-1-alkanones and their analogues with partial conformational restriction.

Inhibitors of acetylcholinesterase (AChE) have been designed based on a working hypothesis of the enzyme's active site. These compounds were tested for their inhibitory activities on AChE and omega-[N-ethyl-N-(phenylmethyl)amino]-1-phenyl-1-alkanones (3) were found to be potent inhibitors. Various analogues of 3 were prepared to study the effect on AChE inhibition of partial restriction of conformation. Compounds with potent AChE inhibition were further evaluated in terms of central selectivity: the ratio of central action (ameliorating effect on scopolamine-induced memory impairment using a T-maze alternation task) to peripheral action.

Animals↗
PubMed1993

Improved oral absorption of a poorly water-soluble drug, HO-221, by wet-bead milling producing particles in submicron region.

N-[[[4-(5-Bromo-2-pyrimidinyloxy)-3-chlorophenyl]amino]carbonyl]-2 -nitrobenzamide (HO-221) is being developed as an anticancer agent with a novel mode of action. HO-221 shows poor oral absorption and is only slightly soluble in water (0.055 micrograms/ml at 37 degrees C). In this study, it was shown that the reduction in particle size of HO-221 to the submicron region (0.453 microm, mean by volume) could be achieved by a wet milling in a decaglycerin monolaurate aqueous solution with small glass beads. The wet milling suspension obtained showed improved dissolution rate and oral absorption in rats. A solid dosage form could also be made from that suspension with addition of sucrose palmitate which prevented aggregation caused by the hydrophobic interaction. The solid dosage form thus obtained showed twice as much oral absorption in dogs as the preparation made by dry milling.

Animals↗
PubMed1993

[The intracuff pressure changes in N2O gas-barrier cuff made of a special material].

During inhalation anesthesia using N2O, the intracuff pressure has been reported to increase due to diffusion of N2O into the cuff. The excessive intracuff pressure may produce ischemia of the tracheal mucosa. In this study, the changes in the intracuff pressure of endotracheal tube with a cuff made of a material with high N2O gas-barrier properties were compared with those of the normal endotracheal tubes. Forty adult patients (16 males and 24 females) were anesthetized with oxygen 2 l.min-1, N2O 4 l.min-1 and isoflurane under controlled ventilation and they were divided into the following three groups according to the type of the endotracheal tube used: the tube with a standard cuff made by PORTEX Co. Ltd; the tube with a profile cuff (high volume cuff) made by PORTEX Co. Ltd; the tube with gas-barrier cuff made by TERUMO Co. Ltd. The changes of each intracuff pressure were recorded continuously for 180 minutes after cuff inflation. A marked increase of the pressure was observed after inhalation of N2O in standard and profile cuff groups. In gas-barrier cuff group, there was a tendency of increasing cuff pressure without a statistically significant difference. The present study suggests that the use of a cuff with a material of high N2O gas-barrier properties would be effective to prevent increased intracuff pressure by N2O diffusion, and this would be especially useful during long anesthesia and hypotensive anesthesia.

Adult↗
PubMed1993

Effect of leukotrienes on sheep airway smooth muscle.

The effects of leukotrienes (LT) C4, LTD4, LTE4 and LTB4 on the development of isometric tension by sheep airway smooth muscle were determined in a tissue bath. LTE4 (1.5 x 10(-7) M) had no contractile effect. LTB4 contracted only lung parenchymal strips. LTC4 (8 x 10(-8) M) and LTD4 (1.1 x 10(-7) M) caused contractions in trachea, bronchi and lung parenchyma that developed slowly and persisted. The tracheal contractions caused by LTD4 and ACh were potentiated approx. 30% by the cyclooxygenase inhibitor meclofenamate (10(-6) M). Meclofenamate had no effect on leukotriene induced contractions in bronchi or lung parenchymal strips. The bronchodilator prostaglandins PGI2 and PGE2 were released from sheep trachea at rest and after contraction by LTD4. Inhibition of their release by meclofenamate may explain the potentiation of LTD4 contractions by meclofenamate. In vitro, LTD4 and LTC4 have potent contractile effects on sheep airway smooth muscle that are not mediated by the secondary release of constrictor cyclooxygenase products. These leukotrienes may play a substantial role in the pathogenesis of allergen and endotoxin induced lung mechanics changes in sheep.

Animals↗
PubMed1993

Effects of alpha 1-proteinase inhibitor on chemotaxis and chemokinesis of polymorphonuclear leukocytes: its possible role in regulating polymorphonuclear leukocyte recruitment in human subjects.

A variety of biologic products derived from bacteria, inflammatory cells, and active degraded proteins have been identified as having chemotactic activity essential for polymorphonuclear leukocyte (PMN) recruitment to the site of inflammation. Little is known, however, concerning factors responsible for regulating the intensity and duration of PMN recruitment. Evidence is growing that proteinase inhibitors modify the migrating ability of PMNs, although the physiologic implications of this have eluded clarification. In an attempt to hypothesize a role of alpha 1-proteinase inhibitor (alpha 1-Pi) in PMN recruitment to inflammatory sites, we examined the effects of alpha 1-Pi in different physiologic concentrations on PMN migration with a microchemotaxis chamber technique. Alpha 1-proteinase inhibitor had both stimulatory and inhibitory effects on cell migration, depending on its concentration. The inhibitor was active in inducing both directed locomotion (chemotaxis) and nondirected locomotion (chemokinesis) in concentrations of 0.02, 0.2, and 2 mg/ml, with maximum potency in both cases at 0.2 mg/ml (corresponding to the normal alveolar surface fluid level in the lung). Alpha 1-proteinase inhibitor impaired chemotactic responsiveness to known chemoattractants at 2 and 10 mg/ml (corresponding to normal and inflammatory blood levels, respectively) in order of potency. These results suggest that alpha 1-Pi may play a role in regulating inflammatory processes, especially in the lung, through its stimulatory and inhibitory effects, depending on its concentration.

Chemotaxis, Leukocyte↗
PubMed1992

High-performance liquid chromatographic determination of pamaquine, primaquine and carboxy primaquine in calf plasma using electrochemical detection.

A high-performance liquid chromatographic method with electrochemical detection is described for quantification of pamaquine, primaquine and carboxy primaquine in calf plasma. After the proteins had been precipitated with acetonitrile, the drugs were separated on a 5-microns C18-modified polymer gel column with an isocratic mobile phase. The detection limit was 0.01 microgram/ml in plasma for all three compounds. The applicability of the method in pharmacokinetic studies was demonstrated by determining the plasma concentrations of the three substances in calves administered a single dose of pamaquine or primaquine.

Aminoquinolines↗