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Biomedical subjects

A Fukunaga

Publications and source records attributed to A Fukunaga.

At least 19 recordsLinked to original sources
PubMed2000

Dose and dose-rate effects of X rays and fission neutrons on lymphocyte apoptosis in p53(+/+) and p53(-/-) mice.

Following the exposure of mice to X rays or fission neutrons, the frequency (F) of apoptosis was measured after 4 h, and the weight loss or lymphocyte content loss in the thymus and spleen was measured after 24 h. In p53(+/+) mice, F increased linearly with the dose (D (Gy)) and the induced rate per Gy of F (detected by TUNEL staining) was 0.05 and 0.23 for X rays and fission neutrons, respectively. Therefore, the RBE of fission neutrons was 4.6 for apoptosis induction. This indicates that radiation-induced apoptosis is mostly due to double strand breaks (DSBs) in DNA because we previously obtained almost the same RBE value of fission neutrons for the induction of crossover mutations in Drosophila melanogaster, which arise from the recombinational repair of DSBs. In p53(+/+) mice, decreases in the organ weight and the lymphocyte content were observed for the thymus and the spleen 24 h after X-irradiation. These atrophic changes in the thymus and the spleen quantitatively corresponded to the total apoptotic cell deaths occurring in them. However, in p53(-/-) mice, no vigorous apoptosis was induced after X-irradiation, and hyperplastic changes in the weight and the lymphocyte content appeared in the thymus and the spleen 24 h after X-irradiation. In p53(+/+) mice, there was no difference in the induced rate per Gy of reduction in the surviving fraction of lymphocytes between acute (0.4 Gy/min) and chronic (3 mGy/min) gamma-irradiations. Namely, radiation-induced apoptosis in lymphocytes is a dose-rate independent event.

Animals↗
PubMed1999

A novel class of Na+ and Ca2+ channel dual blockers with highly potent anti-ischemic effects.

A series of novel arylpiperidines (4a-d) which have highly potent blocking effects for both neuronal Na+ and T-type Ca2+ channels with extremely low affinity for dopamine D2 receptors were synthesized. Among these compounds, 1-(2-hydroxy-3-phenoxy)propyl-4-(4-phenoxyphenyl)-piperidine hydrochloride (4c; SUN N5030) exhibited remarkable neuroprotective activity in a transient middle cerebral artery occlusion (MCAO) model.

Animals↗
PubMed1999

Neuropsychological evaluation and cerebral blood flow study of 30 patients with unruptured cerebral aneurysms before and after surgery.

BACKGROUND: We have recently had many opportunities to operate on patients who presented with no neurologic deficits and were incidentally detected to have unruptured cerebral aneurysms. Therefore, it is very important to know how craniotomy affects the normal brain when making decisions regarding surgery for asymptomatic cerebral diseases. METHODS: Thirty patients with unruptured cerebral aneurysms were evaluated. Aneurysm sites were as follows: internal carotid artery (ICA) (eight cases), anterior communicating artery (ACoA) (seven), middle cerebral artery (MCA) (five), basilar artery-superior cerebellar artery (BA-SCA) (two), and multiple aneurysms (three) [bilateral MCA: (two), ICA + Basilar top: (one)]. These patients underwent neuropsychological examinations [the Mini-Mental State (MMS) test, the "Kana-hiroi" test, and the "Maze" test] and single photon emission computed tomography (SPECT) before and after surgery. RESULTS: The details of the 17 cases whose Kana-hiroi tests deteriorated 1 month after surgery are as follows: ACoA: seven, MCA: five, ICA: three, BA: two. SPECT showed a decrease in CBF in nine cases (ACoA: six, ICA: two, MCA: one). There was a statistically significant difference (p<0.05) between patients with ACoA aneurysms and ICA aneurysms. Three months after operation, all of the patients with neuropsychological deterioration and four of the six low CBF patients recovered to preoperative levels. CONCLUSIONS: These results indicated that the operation for unruptured cerebral aneurysms is moderately safe and meaningful; such a study should be required to determine when those patients could return to normal life.

Adult↗
PubMed1999

Insecticidal properties of 3-aminopropyl(methyl)phosphinic acid and its effect on K(+)-evoked release of acetylcholine from cockroach synaptosomes.

3-Aminopropyl(methyl)phosphinic acid (APMP), a potent agonist of mammalian GABAB receptors, caused prostration in houseflies (Musca domestica L.) on injection into their thoraces, with an ED50 value of 0.42 microgram/fly. The 48-h LD50 values of APMP were estimated to be 0.45 and 5.6 micrograms/fly in the presence and absence of piperonyl butoxide, a mixed-function oxidase inhibitor, respectively. Analogues of APMP, bearing a longer or shorter side chain by a CH2 unit, or a phenyl group in the place of the methyl group, were without effects. In perfusion assays with synaptosomes prepared from the thoracic/abdominal nerve cords of cockroaches (Periplaneta americana L.), 1 mM APMP reduced K(+)-evoked acetylcholine release to 10.4% of the control. These findings indicate that the--physiologically important site of action of APMP, which might be implicated in neurotransmitter release, is present in insect neurons.

Acetylcholine↗
PubMed1999

Ophthalmomyiasis caused by Sarcophaga crassipalpis (Diptera: Sarcophagidae) in a hospital patient.

Nine sarcophagid larvae were found on the right eyelid, cornea, and bulbar conjunctiva of a debilitated patient in a hospital in Osaka, Japan. Inflammation of the right eyelid and conjunctival congestion, probably initiated or aggravated by the larvae, were found. The larvae were removed and reared for accurate identification, and, on the basis of the characteristics of the 3rd instar and adult flies, the species was identified as Sarcophaga crassipalpis Macquart. This is a report of ophthalmomyiasis caused by this facultative parasite in a human. Patients with diminished consciousness in hospitals need protection from flies.

Aged↗
PubMed1999

[A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression and neuroendoscope].

A case of enlarged infundibular dilatation diagnosed by vertebral angiograms with carotid compression was reported. A 57-year-old woman suffered from headache. She underwent MRA which revealed left internal carotid artery aneurysm. Left common carotid angiograms suggested a left saccular internal carotid artery aneurysm (4 mm x 6 mm) without a posterior communicating artery. However, it was confirmed to be an enlarged infundibular dilatation on left vertebral angiograms with carotid compression. It was confirmed at operation microscopically and neuroendoscopically, and the dilatation was treated by coating. When carotid angiograms reveal no posterior communicating artery, it is difficult to differentiate the origin of posterior communicating artery from internal carotid artery-posterior communicating artery junction aneurysms. Vertebral angiograms with carotid compression is useful for the differentiation for the exact diagnosis.

Aneurysm↗
PubMed1998

Plasma cell granuloma extending from the extracranial to the intracranial space associated with Epstein-Barr virus infection.

A 70-year-old male presented with a plasma cell granuloma extending from the extracranial to the intracranial space. Findings of preoperative magnetic resonance imaging and intraoperative observation indicated that the lesion extended from the temporal muscle to the subarachnoid space, penetrating the frontal bone. The subarachnoid lesion was composed of neutrophils indicating the presence of acute or subacute inflammation. The final diagnosis of the resected tumor was plasma cell granuloma. High levels of antibodies against Epstein-Barr (EB) virus in the cerebrospinal fluid and the immunohistochemical demonstration of EB nuclear antigens in the plasma cell granuloma suggested that EB virus infection was associated with the development of plasma cell granuloma in this patient.

Aged↗
PubMed1991

Streptococcal adherence to uncoated and saliva-coated restoratives.

The adherence of Streptococcus sanguis and S. mutans to seven restoratives in the presence and absence of an artificial salivary pellicle has been investigated. The physiochemical surface characteristics of the bacteria and of the restoratives were also measured, together with the effect of salivary coating of restoratives. Zeta potential of uncoated restoratives showed a positive correlation with the number of adherent S. mutans cells and S. sanguis cells. S. sanguis showed a positive correlation with the hydrophobicity of uncoated restoratives. The surface hydrophobicity was decreased upon saliva coating, whereas the zeta potential was slightly increased. The contact angles or zeta potentials of saliva-coated restoratives were positively correlated with those of uncoated restoratives. The number of adherent cells of both S. sanguis and S. mutans to saliva-coated restoratives were decreased after the coating. Zeta potential of saliva-coated restoratives showed a positive correlation with the numbers of adherent S. mutans cells, suggesting that non-specific electrostatic interactions have an important role in the adherence of this species.

Bacterial Adhesion↗
PubMed1989

[Effects of carbon dioxide (hypocapnia and hypercapnia) on tissue blood flow and oxygenation of liver, kidney and skeletal muscle in the dog].

UNLABELLED: We investigated the effects of carbon dioxide on the splanchnic visceral organs (liver and kidney) as well as skeletal muscle in the anesthetized dog. Thirty two adult mongrel dogs were anesthetized with sodium pentobarbital, intubated and ventilated mechanically with 100% oxygen to maintain normocapnia. After laparotomy, miniature Clark-type polarographic oxygen electrodes were placed on the surfaces of liver, kidney and rectus femoris muscle. Electromagnetic blood flow (BF) probes were also applied to hepatic artery (HA), portal vein (PV), left renal artery (RA) and left femoral artery (FA). After a stable normocapnic ventilation, the hypocapnia was produced by increasing respiratory rate, and the hypercapnia was induced by adding the exogenous carbon dioxide. RESULTS: Hyperventilation resulted in a significant decrease in HABF, PVBF, liver surface PO2 and kidney surface PO2 in parallel with the decreased PaCO2, but these parameters increased dose dependently when the carbon dioxide was added to the inspired gas (hypercapnic hyperventilation). On the contrary, FABF and skeletal muscle surface PO2 increased by hypocapnia and decreased during hypercapnia. Neither PaCO2 or cardiac output showed any significant change during the entire experiment. Arterial PCO2 appears to exert significant effects on both splanchnic and skeletal muscle perfusion as well as corresponding changes in tissue oxygenations. It is possible that injudicious and prolonged hypocapnic hyperventilation may seriously compromise splanchnic organ perfusion and oxygenation.

Animals↗
PubMed1988

Streptococcal adherence on various restorative materials.

The adherence of Streptococcus sanguis ATCC 10556, S. sanguis ATCC 10557, S. mutans Ingbritt, and S. mutans OMZ 176 to the surfaces of composite resins, amalgam alloys, and a Au-Ag-Pd alloy was measured. Adhesion was correlated with values for hydrophobicity and zeta-potential of the bacteria and the restorative materials. The hydrophobicity of the restoratives showed a positive correlation between the numbers of adherent S. sanguis cells, suggesting that hydrophobic interactions are important for the adherence of this bacterial species. In contrast, the numbers of adherent S. mutans cells showed a positive correlation with the zeta-potential of the restoratives, suggesting that electrostatic interactions are important in adherence of this bacterium.

Bacterial Adhesion↗