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Biomedical subjects

T Minami

Publications and source records attributed to T Minami.

At least 181 records · Page 10Linked to original sources

Identification of metallothionein isoforms with capillary zone electrophoresis using a polyacrylamide-coated tube.

Metallothionein (MT) isoforms from various liver tissues were separated with capillary zone electrophoresis (CZE) using a polyacrylamide-coated tube at neutral pH. The electrophoresis was performed on MT-1 and MT-2 purified from mouse, rat, rabbit and human livers. The retention times of mouse and rat MT-1 coincided, while the retention times of rabbit and human MT-1 were longer. The retention times of MT-2 purified from the four sources were the same. MT-1 and MT-2 separated more definitely with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-Tris buffer (25 mM, pH 7.4) than with N-tris(hydroxymethyl)methyl-3-aminopropane sulfonic acid (TAPS)-Tris buffer (25 mM, pH 7.7) or with N-(2-acetamido)iminodiacetic acid (ADA)-Tris buffer (25 mM, pH 7.4). In addition, liver MT isoforms prepared from Zn- or Cd-administered mice could be separated.

Acrylic Resins↗

Magnetoencephalographic analysis of rolandic discharges in benign childhood epilepsy.

We report the detailed analysis of the generator and propagation of rolandic discharges in benign childhood epilepsy with centrotemporal spikes by means of 37-channel magnetoencephalography with neuromagnetic three-dimensional dipole localization. Equivalent current dipoles of prominent negative sharp waves of rolandic discharges appeared as tangential dipoles in the rolandic region, positive poles being situated anteriorly. These equivalent current dipoles showed a relatively limited localization and regular directions compared with other components. Equivalent current dipoles of preceding small positive waves, positive waves following negative sharp waves, and negative slow waves appeared in the vicinity of negative sharp waves. Equivalent current dipoles of rolandic discharges were located around the generator of somatosensory evoked magnetic fields stimulated at the lower lip. These findings suggest that rolandic discharges are generated through basically a mechanism similar to that for the middle-latency components of somatosensory evoked responses.

Child↗

Analysis of interaction between cadmium and metallothionein isoforms by capillary zone electrophoresis.

The effects of cadmium on the peak area of metallothionein (MT) protein were studied by capillary zone electrophoresis with a polyacrylamide-coated tube at neutral pH. When cadmium was added to a commercial standard MT-1 isoform prepared from rabbit liver, the peak are of the MT-1 isoform decreased in a time- and dose-dependent manner. The MT-2 isoform also decreased with time, but the rate of decrease was lower than that of the MT-1 isoform. When ethylene glyco-bis-(beta-aminoethyl ether)-N,N,N'N'-tetraacetic acid (EGTA) was added to a solution containing cadmium and MT-1, the peak area recovered with increasing concentration of EGTA. Zinc caused a slight decrease in the peak areas of MT-1 and MT-2 compared with cadmium, while addition of sodium did not decrease the areas. Furthermore, the peak areas of MT isoforms of the crude extract prepared from zinc-treated mice also decreased with increasing concentration of cadmium. These results indicate that cadmium may changed the charge of MT, which may account for the observed differences in electrophoretic behavior.

Animals↗

Effects of erythromycin in chronic idiopathic intestinal pseudo-obstruction.

The prokinetic effects of erythromycin, a macrolide antibiotic, on the gastrointestinal tract as a motilin receptor agonist and its potential value for the treatment of gastrointestinal motility disorders have recently attracted interest. The effects of erythromycin on the clinical symptoms and gastrointestinal motility of patients with chronic idiopathic pseudo-obstruction have not been investigated extensively. We presented a case of chronic idiopathic intestinal pseudo-obstruction, in a 67-year-old man in whom oral erythromycin (900 mg/day) dramatically improved postprandial abdominal distention, nausea, and vomiting. Other agents with prokinetic effects on intestinal motility, i.e., cisapride, domperidone, metoclopramide, and trimebutine maleate did not have a favorable effect. Gastric emptying, measured by the sulfamethizole method; and intestinal transit, evaluated using radio-opaque markers, were markedly improved by treatment with erythromycin. Our experience suggests that the prokinetic effects of erythromycin may be of therapeutic value in chronic idiopathic intestinal pseudo-obstruction.

Administration, Oral↗

Age-related change of mineral content in the human thoracic aorta and in the human cerebral artery.

The relative contents (RCs) of mineral elements in aortae and cerebral arteries from 23 subjects, with ages ranging between 45 and 99 yr, were analyzed by inductively coupled plasma atomic emission spectrometry. The RCs of calcium, phosphorus, and magnesium in the aortae increased markedly after the age of 70. While the RC of sulfur in aortae decreased gradually after that age. It was found that accumulation of calcium and phosphorus occurred primarily in the tunica media of aorta, and secondarily in the tunica intima. Furthermore, the RCs of calcium, phosphorus, and magnesium in cerebral arteries increased markedly after the age of 70, whereas the RC of sulfur in cerebral arteries decreased after age 70. It was found that accumulation of calcium and phosphorus in the cerebral arteries were 30 and 60%, respectively, lower than those in the aortae with ages ranging between 45 and 99 yr.

Aged↗

Difference of mineral contents in human intervertebral disks and its age-related change.

To establish a difference of the relative contents (RCs) of elements among the cervical, thoracic, and lumbar intervertebral disks and its age-related change, the intervertebral disks between the axis and the sacrum, which were resected from the nine cadavers who died at 53 to 99 yr old, were analyzed by inductively coupled atomic plasma emission spectrometry. It was found that both the RCs of calcium and phosphorus were high in the cervical disks, especially the highest in the disk between the 6th and 7th cervical vertebrae, and lower in the order of the cervical, thoracic, and lumbar intervertebral disks. In regard to the RCs of sulfur and magnesium, there were no significant differences among the cervical, thoracic, and lumbar intervertebral disks. In addition, it was found that both the RCs of calcium and phosphorus in the cervical intervertebral disks started to increase in the sixth decade of life, became the highest in the eighth decade of life, and then decreased.

Aged↗

An improved method for estimating original mineral contents in excavated bone using sulfur.

Trace element analysis in excavated bones is complicated by the lack of a reliable index for estimating the original amount of bone material. In this study, we subjected modern human bones to alkali treatment to simulate aging. Alkali treatment of vertebrae with attached muscle did not affect sulfur (S) content; it increased the magnesium (Mg), phosphorus (P), and zinc (Zn) contents, and tended to decrease iron (Fe) content of the bones. When vertebrae cleaned of muscle were used, alkali treatment did not affect S and Fe contents but increased Mg, P, Ca, and Zn contents. Ca and S contents were higher in excavated bones (200-1300 yr old) than in their surrounding soils. In contrast, S, Mg, and Ca contents per dry weight did not differ between the excavated bones and the alkali-treated modern bones. These results indicate that S can provide a more accurate index of excavated bones than the often-used Ca content or dry wt measures, especially for bones excavated from calcium-rich soils.

Archaeology↗

Involvement of glutamate receptors in strychnine- and bicuculline-induced allodynia in conscious mice.

BACKGROUND: Glycine and gamma-aminobutyric acid (GABA) are inhibitory neurotransmitters that appear to be important in sensory processing in the spinal dorsal horn. Intrathecal administration of strychnine (strychnine-sensitive glycine receptor antagonist) or bicuculline (GABAA antagonist) was reported to induce allodynia. Although the strychnine-induced allodynia was shown to be mediated through the N-methyl-D-aspartate (NMDA)-type glutamate receptor, it is not clear whether the bicuculline-evoked-allodynia is mediated through the glutamate receptor system or how different the allodynia induced by strychnine and bicuculline are. METHODS: Male ddY mice weighing 20 +/- 2 g were used in this study. A 27-G stainless-steel needle attached to a microsyringe was inserted between the L5 and L6 vertebrae by a slight modification of the method of Hylden and Wilcox. Drugs in vehicle were injected slowly into the subarachnoid space to conscious mice at 22 +/- 2 degrees C. The volume of the intrathecal injection was 5 microliters. Studies on allodynia were carried out essentially according to the method of Yaksh and Harty. RESULTS: The intrathecal administration of strychnine or bicuculline in conscious mice resulted in allodynia elicited by nonnoxious brushing of the flanks. The maximum allodynia induced by strychnine was observed 5 min after intrathecal injection, but that induced by bicuculline was observed 10 min after intrathecal injection. Both responses gradually decreased over the experimental period of 50 min. The allodynia induced by strychnine was dose-dependently relieved by NMDA receptor antagonists (D-AP5, ketamine, and 7-C1-KYNA) and non-NMDA receptor antagonists (GAMS and CNQX) but not by metabotropic receptor antagonists (L-AP3 and L-AP4). On the other hand, allodynia induced by bicuculline was dose-dependently relieved by GAMS, L-AP3, and L-AP4, but not by D-AP5, ketamine, 7-C1-KYNA, and CNQX. Whereas the strychnine-evoked allodynia was dose-dependently relieved by the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) and the soluble guanylate cyclase inhibitor methylene blue, the bicuculline-induced one was dose-dependently relieved by methylene blue but not by L-NAME. CONCLUSIONS: These results demonstrate that both strychnine- and bicuculline-evoked allodynia were mediated through pathways that include the glutamate receptor and nitric oxide systems but in a different manner. the current study suggests that GABA and glycine may modulate responses to an innocuous tactile stimulus as inhibitory neurotransmitters at presynaptic and postsynaptic sites in the spinal cord, respectively.

Animals↗

Magneto-encephalographical analysis of focal cortical heterotopia.

Focal cortical heterotopia is often associated with intractable seizures. Recent papers have reported that magnetic resonance imaging (MRI) demonstrates cortical heterotopia well compared with other imaging modalities, e.g. computed tomography scan. The authors analyzed the localization of epileptic spike foci of focal cortical heterotopia by 37 channel magnetoencephalography (MEG), and superimposed these dipoles on MRI. The estimated dipoles were observed to be located in a limited area, which corresponded to a focal cortical heterotopia on MRI. The present paper demonstrates that the combination of MEG and MRI is very advantageous for determination of the three dimensional localization of epileptic foci in patients with focal cortical heterotopia.

Adult↗

Detection of platinum in the brain of mice treated with cisplatin and subjected to short-term hypoxia.

Cisplatin is widely used for cancer treatment but has strong side-effects, including nephrotoxicity. Neurotoxicity has been thought to be limited to peripheral damage because the blood-brain barrier is thought to be impervious to hydrophilic substances such as cisplatin. Because anoxic ischaemia has been associated with lesions of the barrier, inductively coupled plasma mass spectrometry has been used to monitor the accumulation of platinum in the brains of mice treated with cisplatin and exposed to oxygen-deficient atmospheres. Platinum was detected in the cerebral cortex of mice 24 h after the administration of cisplatin (3 mg kg-1) followed by exposure for 60 s to an atmosphere containing 7% oxygen, but not in the cerebral cortex of mice exposed to normal atmospheres. Platinum was also observed in the cerebral cortex after exposure for 120 s to an atmosphere containing 14% oxygen, and platinum levels increased as the concentration of oxygen was reduced. The highest platinum levels were obtained 10 h after administration of cisplatin and exposure for 120 s to an atmosphere containing 7% oxygen. Platinum was still retained in the cerebral cortex one week after administration. In contrast, platinum levels in the blood and kidney decreased with time. Platinum levels were measured in seven regions of the brain: the right and left cerebral cortices, the basal ganglia, the thalamus and hypothalamus, the bulbus olfactorius, the cerebellum, and the mesencephalon. When cisplatin was administered to mice not subjected to hypoxia, platinum was not detected in the right and left cerebral cortices, basal ganglia or the thalamus and hypothalamus, but was detected in the bulbus olfactorius, cerebellum and mesencephalon. When such mice were exposed to low levels of oxygen, however, platinum was detected in the right and left cerebral cortices, the basal ganglia and the thalamus and hypothalamus. Platinum levels in the cerebellum and mesencephalon of mice exposed to low levels of oxygen were higher than those of mice exposed to normal air. In addition, platinum levels in the bulbus olfactorius were significantly higher than those in the other regions, although the platinum content of the bulbus olfactorius was not affected by hypoxia. From these observations, it is concluded that platinum is easily accumulated in the bulbus olfactorius after the administration of cisplatin, and that after exposure to atmospheres containing low levels of oxygen, platinum easily passes through the blood-brain barrier and accumulates in all parts of the brain.

Animals↗

Role of prostaglandins in intestinal epithelial restitution stimulated by growth factors.

Mucosal integrity is reestablished after superficial injuries by a rapid resealing process, termed epithelial restitution, that is regulated by several growth factors and cytokines. Growth factors are also known to stimulate the synthesis of endogenous prostaglandins that mediate important functions in intestinal epithelial cells. Therefore, we examined the effect of endogenous eicosanoid production modulators, piroxicam, dexamethasone, and nordihydroguaiaretic acid (NDGA) on intestinal epithelial restitution using two cultured cell wound-resealing models, IEC-6 and Caco-2 cells. Epidermal growth factor, transforming growth factor-beta, hepatocyte growth factor, and fetal calf serum (FCS) accelerated intestinal epithelial restitution, and piroxicam significantly suppressed these stimulatory effects. Dexamethasone mimicked the action of piroxicam. No additive effect of piroxicam and dexamethasone was observed. NDGA did not affect epithelial restitution. Piroxicam abolished the increase in 6-ketoprostaglandin F1 alpha (PGF1 alpha) release induced by FCS. Furthermore, addition of a stable PGI2 analogue, OP-41483 [5(E)-6,9-deoxa-6,9-methylene-15-cyclopentyl-16,17,18,19,20-pen tanor-PGI2], reversed the slowing of epithelial restitution induced by piroxicam. These results suggest that endogenous prostaglandins play an important role in regulating intestinal epithelial restitution.

6-Ketoprostaglandin F1 alpha↗

Phospholipase A2 stimulation of rat intestinal epithelial cell (IEC-6) migration.

The effect of phospholipase A2 (PLA2) on intestinal epithelial cell migration was investigated using an in vitro wounding model of confluent monolayers of IEC-6. PLA2 (0.001-2 U/ml) enhanced IEC-6 cell migration in a dose dependent manner. Addition of 4-bromophenacyl bromide (BPB) (a PLA2 inhibitor) to PLA2 completely blocked the migration-promoting effect. However, addition of piroxicam (a cyclooxygenase inhibitor) or nordihydroguaiaretic acid (a lipoxygenase inhibitor) had no influence on the effect. Lysophosphatidylcholine (lysoPC) (0.01-5,000 ng/ml), one of the products of phosphatidylcholine by PLA2, dose-dependently enhanced IEC-6 cell migration as well. A combination of PsLA2 (1 U/ml) and lysoPC (1,000 ng/ml) had no additive effect or migration. Moreover, the migration-promoting effect of PLA2 that was blocked by BPB was recovered by lysoPC. After pretreatment of IEC-6 cells with replication-inhibiting doses of mitomycin C, the enhanced migration induced by PLA2 or lysoPC was still observed. These observations suggest that PLA2 may, independently of proliferation, enhance intestinal epithelial cell migration mainly via lysoPC.

Acetophenones↗

Is the intracellular pH threshold an anaerobic threshold from the view point of intracellular events?: a brief review.

Intracellular biochemical changes could be monitored noninvasivery and continuously by using nuclear magnetic resonance (NMR). In about the last decade, intracellular behavior of phosphorus compounds and pH during muscle contraction in man have been studied by 31P nuclear magnetic resonance spectroscopy (31P-MRS). During incremental load, lactic acidosis was followed by a decline in intracellular pH. 31P-MRS studies has been definitely proved that this change in intracellular pH shows the threshold behavior. Some reports discussed the intracellular pH threshold (pHT) as an anaerobic threshold (AT) from the view point of intracellular events. However, our studies revealed that pHT did not reflect the onset of lactate production. In this article, studies of intracellular pH of working muscle were reviewed in relation to an anaerobic threshold.

Anaerobiosis↗

Locomotive stereotyped behavior in cynomolgus macaques, Macaca fascicularis.

Primate infants separated from their mothers and kept alone for a long period may exhibit behavioral disorders and develop stereotyped behavior according to genetic predispositions of the infants and environmental factors such as characteristics of the cage. However, it is not clear whether the locomotive and repetitive stereotyped behaviors are related to maternal separation or isolation rearing early in life. The locomotive and repetitive stereotyped behaviors and their relationship were examined with 65 juveniles of cynomolgus macaques kept under artificial conditions. All infants were separated from their mothers and kept with peers. Observations were conducted when they were about three to five years old. The monkeys exhibited locomotive and repetitive stereotyped behavior such as turning, backward somersaulting, and bouncing. Most showed both turning and backward somersaulting. Observations indicated that social interactions with peers following maternal separation at the age of 3 to 5 mo. produce the locomotive and repetitive stereotyped behavior and that turning may change to backward somersaulting for older infants. Further work with controls for several factors is needed.

Age Factors↗

Defecation habits of cats and dogs and contamination by Toxocara eggs in public park sandpits.

The defecation habits of cats and dogs in three sandpits in urban public parks were observed by camcorder. Cats were the main cause of fecal contamination of these sandpits. Most (80%) feline defecations occurred at night between 6:00 pm and 6:00 am. Each of the sandpits was used habitually as a defecation site by 4-24 cats, but these cats seemed to defecate elsewhere, as well. Fecal deposits within the sandpits were evenly distributed and did not tend to be concentrated in one area, suggesting that the cats avoided previously deposited feces when choosing a place to defecate. One sandpit was strongly contaminated and two were weakly contaminated with Toxocara eggs. Because sandpits are widely used as play areas for young children, effective sanitation measures should be implemented to prevent the contamination of sandpits by Toxocara eggs.

Animals↗

Prostaglandin D2 inhibits prostaglandin E2-induced allodynia in conscious mice.

We previously reported that intrathecal administration of prostaglandin (PG) D2 and PGE2 to conscious mice induced hyperalgesia (assessed by a hot-plate test) and that intrathecal administration of PGE2 and PGF2 alpha induced allodynia, a state of discomfort and pain evoked by innocuous tactile stimuli. In the present study, we examined the relationships of pain responses among PGD2, PGE2 and PGF2 alpha, PGF2 alpha additively augmented the allodynia evoked by a submaximal dose (1 ng/mouse) of PGE2. On the other hand, PGD2 dose-dependently blocked the allodynia induced by a maximal dose (10 ng/mouse) of PGE2, with an IC50 of 93.2 pg/mouse, but did not affect the PGE2 (10 ng)-induced hyperalgesia at doses up to 10 ng. BW 245C, an agonist for PGD2 receptors (DP receptors), but not another DP receptor agonist (ZK 110841) blocked the allodynia similarly. The blockade of PGE2-induced allodynia by 10 ng of PGD2 was reversed by the potent and selective DP receptor antagonist BW A868C, in a dose-dependent manner. Intrathecal administration of BW A868C induced allodynia by itself over a wide range, from 10 pg to 100 ng. and the allodynia induced by 100 ng of BW A868C was dose-dependently antagonized by PGD2. These results demonstrate that PGD2 blocked the PGE2-evoked allodynia through DP receptors in the spinal cord, and they imply that endogenous PGD2 may play an inhibitory role in the appearance of allodynia under physiological conditions.

Adrenergic Agonists↗

[A case resectable hepatic metastases of breast cancer following intrahepatic arterial chemotherapy].

A 38-year-old woman who had undergone Patey's operation for left breast cancer in July 1990 was admitted in December 1992 for hepatic metastases. Due to bone metastasis (Th10), oophorectomy and hepatic arterial cannulation were performed. Hepatic arterial chemotherapy and oral chemoendocrine therapy yielded a partial response for liver and unclear metastasis of the bone. She had arterial and oral administration after a hepatectomy in October 1994. The patient has had no recurrent signs now (July 1996). We experienced 522 patients with breast carcinoma and 14 cases (2.7%) of all having hepatic metastases. Hepatic arterial chemotherapy was done in three patients. Although one of them had a complete response, she died after 35 months because of bone, brain and liver metastases. Another case was underwent hepatectomy after arterial chemotherapy, but recurrent liver and bone tumors soon appeared. The mean survival period of 15 hepatic metastases, including the case under study here was 9 months, and the one-year survival rate was 23.4%.

Adult↗