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Biomedical subjects

N Aoyagi

Publications and source records attributed to N Aoyagi.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Validation of dissolution testing: evaluation of vibration levels of dissolution apparatuses].

The collaborative study participated by seven laboratories was carried out to develop a dissolution standard for evaluating vibration levels of dissolution apparatuses using enteric-coated granules of cefalexin (EG). Dissolution apparatuses could be divided into two groups according to their vibration levels and the dissolution test results of EG by the rotating basket method at 50 rpm. The critical value of acceleration was about 0.05 m/s2. The upper limit of normal dissolution rates of EG was calculated from the results of the rotating basket method at 50 rpm obtained from low vibration apparatuses. All high vibration apparatuses used in this study were distinguished by the limit from low vibration apparatuses, although most of them were not distinguished by current USP calibrators. These results suggest that EG would be useful as a calibrator for detection of apparatuses on high vibration levels.

Calibration↗
PubMed1997

DNA polymerase epsilon from Drosophila melanogaster.

We identified a DNA polymerase species in Drosophila melanogaster embryos, and purified it. This polymerase shared some common properties with DNA polymerase epsilon from mammals and yeast as follows; it has a preference for poly(dA)/oligo(dT) as a template/primer, it is highly processive in DNA synthesis, it co-fractionates with 3'-5' exonuclease activity, it is sensitive to aphidicolin and is resistance to ddTTP. The polymerase activity was inhibited in the immuno-precipitation assay with anti-pol-epsilon antibodies, which were produced against a polypeptide coded on the cDNA of a putative Drosophila pol-epsilon we isolated previously. Using these antibodies, Western blot analysis revealed that this polymerase is a 250kDa polypeptide, which is the same size as observed in mammals and yeast. These results indicate that Drosophila produces the epsilon-class of DNA polymerase, and like mammals or yeast, possesses the 5 typical classes of DNA polymerases (alpha to epsilon) in its embryos.

Animals↗
PubMed1997

Additional chromosome abnormalities in transient abnormal myelopoiesis in Down's syndrome patients.

We report a case of transient abnormal myelopoiesis (TAM) with Down's syndrome. As the blast cells had additional chromosome abnormalities (50,XY,+12,+14,+21 x 2), a possibility of acute leukemia was considered from a cytogenetic point of view. But the abnormal clone gradually disappeared without antileukemic therapies. Viewing it together with previous reports of TAM with additional chromosome abnormalities in Down's syndrome babies, its presence does not immediately indicate an aggressive clinical course as in acute leukemia and spontaneous complete hematological remission may be achieved. Thus, a careful follow-up should precede cytogenetic findings helping to determine the therapeutic intervention.

Adult↗
PubMed1997

[Exceptional Application of Content Uniformity Test and Weight Variation Test in the Japanese Pharmacopoeia 13 revision and usage of these tests for in-process tests].

The criteria of Content Uniformity test and Weight Variation test in JP 13 were greatly changed to reduce consumer's risk. The new criteria were set to keep the rate of defectives in lots passing the tests less than the acceptable rate. However, in some cases, the new criteria can not directly be applied to some formulations and several modifications are needed in the criteria. In this report, the several resolution of this problem are represented. The applicability of these tests for in-process tests is also discussed.

Japan↗
PubMed1996

Fatty acids selectively inhibit eukaryotic DNA polymerase activities in vitro.

The in vitro relationship between eukaryotic DNA polymerases and fatty acids was investigated. Some fatty acids strongly inhibited the activities of DNA polymerase alpha and/or beta in vitro. The kinetics of inhibition by linoleic acid showed that DNA polymerase alpha was non-competitively inhibited with respect to the DNA template and substrate (dTTP), while DNA polymerase beta was inhibited competitively with both DNA and substrate.

Animals↗
PubMed1996

Study on early re-rupture of intracranial aneurysms.

The prognosis of patients with early re-ruptured intracranial aneurysms is discouraging. We compared the data on patients suffering re-rupture before the onset of late vasospasm (Early-Re) with those suffering rebleeding thereafter (Late-Re). The operability in the Early-Re group was lower (p < 0.05) and the outcome less satisfactory than that of Late-Re group. Of the Early-Re patients, 83% had a re-rupture within 24 hours of the initial subarachnoid haemorrhage; moreover 46% of these experienced rebleeding within three hours of the initial bleeding. Cases in the Early-Re group tended to belong to Hunt-Hess grade III or IV on admission, of wide spread subarachnoid haemorrhage on CT and of "bump" type aneurysms on angiograms. Based on our experience we propose that early re-rupture may be attributable to the following factors: a gradual and progressive thinning of the wall of bump type aneurysms results in such a large laceration through the fundus of the aneurysm. Re-rupture may occur within a short period after the first rupture because the fibrin net covering the wide laceration cannot tolerate the slight increase in internal pressure within the aneurysmal dome. Therefore, in the patients of Hunt-Hess grade III or IV, conventional angiography, tight holding during CT examination and lumbar puncture, should be avoided during the first three hours after the first bleed. Although early direct operations on patients with high Hunt-Hess grades tend to produce an unsatisfactory outcome, we cannot help these patients with Early-Re without surgical treatment. Not only early direct operation but also first conservative treatment to control systolic blood pressure are very important in patients with Early-Re.

Adult↗
PubMed1996

Effect of destruction force on drug release from multiple unit controlled release dosage forms in humans.

PURPOSE: This study examined the effects of mechanical destructive forces on drug release from controlled release (CR) multiple unit dosage forms in vitro and in vivo and their colonic release, using two CR granules of acetaminophen, AG and BG, which differed in hardness (AG was hard and BG was soft), but which did not depend on agitation speed or pH for their release. METHODS: In vitro release rates were determined using several official methods and the rotating dialysis cell method. Granules were administered to healthy volunteers under fasting and fed conditions. RESULTS: Both granules showed similar release rates under mild destructive conditions in official dissolution tests, but BG showed a faster release rate in the rotating dialysis cell method. In the fasting state, the drug absorption-time profiles of AG and BG were almost equal. In the fed state, the drug release rate of BG increases whereas that of AG is almost equal to the fasted state. The food effect on BG could be caused by an increase in the mechanical stress of the GI tract due to food intake judging from the findings in vitro and in dogs. The colonic release from multiple unit CR products was larger than that from single unit ones. CONCLUSIONS: In vivo release of drug from a multiple unit CR product that is structurally weak is affected by mechanical stresses, which differ among human subjects but are increased by food ingestion. Colonic release from multiple unit CR products is larger than that from single unit products.

Acetaminophen↗
PubMed1996

Effects of atropine and loperamide on the agitating force and GI transit time in dogs in drug absorption studies.

There are difficulties in drug absorption studies using dogs because of different gastrointestinal (GI) conditions between these animals and humans, including shorter intestinal transit time and strong agitation force in the GI tract. We attempted to modify the agitation force and GI transit time using atropine and loperamide. The agitation force was examined based on in vitro/in vivo correlation for two controlled release (CR) formulations of acetaminophen. Atropine treatment considerably reduced the agitating force whereas that of loperamide did not.

Acetaminophen↗
PubMed1996

[Assessment of bioequivalence].

Bioequivalence tests in Japan are now under the improvement according to the WHO guidance. This article describes the desirable assessment of bioequivalence where the use of discriminatory subjects, application of confidence interval methods, logarithmic transformation of pharmacokinetic data are recommended. The role of dissolution tests in bioequivalence assessment is also discussed.

Biological Availability↗
PubMed1995

Estimation of agitation intensity in the GI tract in humans and dogs based on in vitro/in vivo correlation.

In this study, we assessed the hydrodynamic flow around a dosage form in the GI tract in humans by comparing the characteristics of in vitro and in vivo release of two different types of controlled release acetaminophen (paracetamol) tablets, A and B. The former tablet showed an agitation speed-dependent release at a high speed range (50-100 rpm), whereas the latter showed this characteristic at a low speed range (10-50 rpm). The mean release amount-time profiles of tablets A and B in humans showed biphasic characteristics, and the first phase of the absorption profiles of A and B was close to their in vitro profiles at a paddle speed of 10 rpm. The in vivo profiles were also superimposable on in vitro dissolution curves obtained by the flow-through cell method at a flow rate of 1 mL/min (velocity 0.89 cm/min) or less. These results indicate that the hydrodynamic flow around the dosage forms in the human GI tract could be extremely low. The in vivo release rate of these tablets in dogs was greater than in humans, and was estimated to be equivalent to the release rate determined by the paddle method at 100 rpm. This indicates that a higher agitation intensity in the GI tract in dogs than in humans may be one cause of the discrepancies between humans and dogs in drug absorption studies.

Acetaminophen↗
PubMed1995

Oral solid controlled release dosage forms: role of GI-mechanical destructive forces and colonic release in drug absorption under fasted and fed conditions in humans.

PURPOSE: This study was undertaken to examine the effects of mechanical destructive forces on drug release from controlled release (CR) dosage forms in vitro and in vivo and their colonic release, using two CR tablets of acetaminophen A and B, showing slower and faster erosion rates, respectively. METHODS: In vitro release rates were determined by several official methods. Tablets were administered to healthy volunteers under fasting and fed conditions. RESULTS: Both tablets showed similar release rates under mild destructive conditions (e.g., paddle method at 10 rpm) but CR-B showed faster release under highly destructive conditions (e.g., rotating basket method at 150 rpm), where the tablet was eroded. The in vivo release from CR-B was faster than from CR-A, possibly because of enhanced erosion. The variable in vivo release from CR-B indicated large inter-subject differences in destructive GI forces. The fastest in vivo release from CR-B among individuals was approximated by the in vitro dissolution determined by destructive methods such as the rotating basket at 150 rpm. The slowest in vivo release from tablets A and B was lower than the dissolution by the paddle method at 10 rpm. The release from both tablets was markedly reduced at 3-4 hrs after dosing irrespective of feeding conditions which can be attributed to release inhibition in the colon. CONCLUSIONS: Effects of GI destructive forces on the tablet erosion and the release inhibition in the colon must be considered in the development of CR dosage forms.

Acetaminophen↗
PubMed1994

Drosophila DNA polymerase delta. Purification and characterization.

A DNA polymerase with properties similar to mammalian polymerase delta has been isolated to near homogeneity from early embryos of Drosophila melanogaster. A combination of exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that this enzyme has a total molecular mass of 185 kDa and is composed of 138- and 47-kDa polypeptides. Its isoelectric point is 6.8. This polymerase activity is strongly inhibited by N-ethylmaleimide, aphidicolin, and high KCl concentration but is relatively insensitive to 2',3'-dideoxythymidine 5'-triphosphate. There was no reaction in an immunological test using monoclonal antibody against Drosophila DNA polymerase alpha. In a final purification step, this polymerase activity was accompanied by 3'-->5'-exonuclease activity as expected proof-reading activity. This polymerase activity is remarkably stimulated by mouse proliferating cell nuclear antigen, which is structurally and immunologically very similar to a Drosophila counterpart. These properties clearly indicate this enzyme belongs to the category of DNA polymerase delta.

Animals↗
PubMed1993

A Ki-1-positive cell line expressing Epstein-Barr virus antigens, established from a child with Ki-1-positive lymphoma.

We report here the establishment of a CD30 (Ki-1) antigen-positive cell line 'Ki-JK' from a child with anaplastic large cell lymphoma. We characterized this cell line and show that: (i) Ki-JK cells do not grow in soft agar but infrequently produce a tumor or suppressed growth when injected into nude mice; (ii) Ki-JK cells expressed Epstein-Barr virus (EBV) antigens, EBV-associated nuclear antigen-2 and latent membrane protein; (iii) Ki-JK cells are labelled by in situ hybridization using an RNA probe derived from the BamHI W fragment of EBV, and (iv) polymerase chain reaction demonstrates the presence of an EBV BamHI W sequence in DNA of lymphoma and Ki-JK cells. These results suggest an etiological role for EBV in the development of some cases of Ki-1-positive lymphomas.

Adolescent↗
PubMed1993

[A case of spontaneous rupture of the ascending aorta].

We report a rare case of spontaneous rupture of the ascending aorta without any evidence of aneurysm formation or aortic dissection. A woman aged 64 was admitted to our cardiac care unit as an emergency patient with severe chest pain. Her face was pale and systolic blood pressure was 70 mmHg in spite of intravenous administration of dopamine (10 micrograms/kg/min). She had a history of hypertension for two years under good medical control. No trace of the chest trauma was noted before her admission. Physical examination revealed neck vein engorgement and distant heart sounds. Chest X-ray film showed enlargement of the cardiac silhouette. ECG showed no evidence of acute coronary syndrome. Pericardial effusion with a floating hematoma-like mass was detected by 2-dimensional echocardiogram. Pericardiocentesis revealed bloody pericardial fluid (Ht: 26%). Aortagraphy was performed resulting in a clinical diagnosis of acute aortic dissection, but there were no signs of a false lumen, aneurysm formation or extravasation of the contrast medium. Although continuous pericardial drainage was performed, she suddenly lost consciousness, collapsed and died. A longitudinal intimal laceration 5 cm long was observed in the ascending aorta. Pathological examination revealed cystic medial necrosis and irregularity of the elastic fibers in the media. No atheromatous plaque was noted in the intima. Spontaneous rupture of the aorta is a life-threatening condition that requires urgent surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Gastric emptying of tablets and granules in humans, dogs, pigs, and stomach-emptying-controlled rabbits.

Rates of gastric emptying of nondigestible tablets and granules in humans were compared with those in three animal models: dogs, minipigs, and stomach-emptying-controlled rabbits. The rates of gastric emptying of both dosage forms in dogs tended to be faster than or similar to those in humans, whereas the rates in pigs were slower. In stomach-emptying-controlled rabbits, no tablets were emptied from the stomach because of their large size. The rate of gastric emptying of granules in rabbits was slow and variable. Food delayed gastric emptying in dogs, especially for tablets. In rabbits, the rate of gastric emptying of granules was faster when the granules were given before feeding, in comparison with that after feeding or under fasting conditions. We concluded that the dog is a better animal model for bioavailability studies under fasting conditions than the pig and the rabbit.

Adult↗
PubMed1991

Endothelin-3 stimulates the hypothalamic-pituitary-adrenal axis.

Endothelin-3 (ET-3) is a member of the novel vasoconstrictive peptide family, identified in porcine central nervous system. Intravenous bolus injection of 1000 pmol/kg of ET-3 in freely moving rats caused significant increases in plasma ACTH and corticosterone levels, almost equivalent to those of 100 pmol/kg of rat corticotropin-releasing hormone (rCRH). The action of ET-3 was virtually abolished by pretreatment of CRH-antagonist, alpha-helical CRH. When ET-3 was added to cultured anterior pituitary cells, neither direct stimulation of ACTH release nor potentiation of rCRH action was noted. The results indicate that ET-3 may function as a neuropeptide and stimulation of the CRH-neurons, direct or inderect, is mainly responsible for activation of ACTH and corticosterone release.

Adrenal Glands↗