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Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 181 records · Page 10Linked to original sources
PubMed1999

Enhancement of vascular permeability by specific activation of protease-activated receptor-1 in rat hindpaw: a protective role of endogenous and exogenous nitric oxide.

1. To clarify the role of the first thrombin receptor/protease-activated receptor (PAR)-1 in an inflammatory process, we tested and characterized the effect of intraplantar (i.pl.) administration of the highly specific PAR-1 agonist TFLLR-NH2 in rat hindpaw. 2. TFLLR-NH2 administered i.pl. at 0.01-0.03 micromol per paw enhanced vascular permeability in the hindpaw and produced paw oedema in a dose-dependent manner. This effect was almost completely abolished by repeated pretreatment with compound 48/80 to deplete inflammatory mediators in mast cells. 3. The NO synthase inhibitor N(G)-nitro-L-arginine methyl ester or N-iminoethyl-L-ornithine, preadministered i.pl., stereospecifically potentiated the i.pl. TFLLR-NH2-induced permeability increase, while the NO donor sodium nitroprusside or NOC-18, given i.pl., suppressed the effect of TFLLR-NH2. 4. These findings demonstrate that specific activation of PAR-1 produces increased vascular permeability accompanied by oedema formation in the rat hindpaw, predominantly via mast cell degranulation, and that endogenous and exogenous NO plays a protective role in the PAR-1-mediated inflammatory event.

Animals↗
PubMed1999

Ethical considerations in anaesthesia journals.

It has been shown that instructions to authors in nonanaesthesia biomedical journals often fail to require authors to state that the study was approved by an ethics committee and informed consent obtained from participants; articles also often omit mentioning these points. We examined 11 English-language journals, which are listed in the 'Anesthesiology' category of 1995 SCI Journal Citation Reports, to see whether the instructions to authors of anaesthesia journals mention the following ethical factors: approval of the study by an ethics committee, informed consent, redundant publication, fraud, authorship, conflict of interest and protection of patients' privacy. We also examined 673 articles which appeared in these anaesthesia journals ( July to December issues of 1996) to see whether they stated acquirement of ethics committee approval and informed consent. All journals addressed the avoidance of redundant publications and unjustifiable authorship. Ten journals required approval of studies and signatures from all authors, eight journals mentioned informed consent. Only seven required the disclosure of any conflict of interest and the protection of patients' privacy. More than 90% of the articles stated that the study was approved and informed consent obtained.

Anesthesiology↗
PubMed1999

Prevention of needle-stick injury. Efficacy of a safeguarded intravenous cannula.

One possible method of reducing the incidence of needle-stick injury is to use needles with safeguard mechanisms. The needle of the Insyte AutoGuard intravenous cannula can be retracted into the safety barrel. One hundred patients were randomly allocated to receive either an 18-gauge conventional Insyte intravenous cannula (group C) or the AutoGuard cannula (group AG) to assess the ease of use and efficacy of the AutoGuard device. It was possible to insert the cannula into the vein within two attempts in all patients; there was no significant difference between two groups with respect to ease of insertion. No problems, such as inadvertent withdrawal of the needle, occurred during insertion in any patient. Handling the withdrawn needle was judged significantly safer in group AG than in group C (p < 0.001). Blood contamination often occurred where a withdrawn needle was placed in group C, whereas no blood stain was detected in any case in group AG (p < 0.001). The AutoGuard cannula provides safer handling of a withdrawn needle without reducing its ease of insertion.

Adolescent↗
PubMed1999

Functional circuitry for the induction of prolonged excitation in the rat spinal dorsal horn.

The neuronal circuitry through which prolonged excitation is generated in the spinal dorsal horn was investigated using optical imaging of neuronal excitation in transverse slices of rat spinal cords. It is known that tetanic stimulation (20 Hz for 1 s) of the dorsal root that activates both A and C primary afferent fibres elicits slow intrinsic optical signals (IOS) in the dorsal horn, seen most intensely in the substantia gelatinosa (SG), lamina II, and that IOS expresses in part the slow synaptic response recorded intracellularly in dorsal horn neurons. We here report that the slow IOS within the SG were completely abolished after an incision was made at the border between the SG and the deeper laminae, but not after an incision within the deeper dorsal horn of the laminae III-V. The result demonstrates directly that, in order to generate prolonged excitation in the SG, the neuronal elements in the deeper dorsal horn must be intact. Thus, the afferent information might be received first by the deeper elements and then transmitted to the SG region, and/or collaboration between the SG and deeper elements is necessary to maintain prolonged excitation in the SG.

Animals↗
PubMed1999

Gastric hyperplastic polyp occurring at the resection site of gastric adenoma.

Endoscopic mucosal resection was carried out in a 70-year-old man with a gastric adenoma. Endoscopy 1 year later revealed a subpedunculated polyp about 1 cm in diameter at the resection site. Pathological examination of the resected specimen showed hyperplasia of the regenerative epithelium. The mechanism of occurrence of hyperplastic polyp at the resection site is discussed.

Adenoma↗
PubMed1999

Placement of the intubating laryngeal mask is easier than the laryngeal mask during manual in-line neck stabilization.

We have compared in 25 patients ease of placement of the conventional and intubating laryngeal masks while the patient's head and neck were stabilized by a manual in-line method, in a randomized, crossover study. After induction of anaesthesia and neuromuscular block, the masks were placed in turn. Adequacy of ventilation and ease of placement (using a 10-cm visual analogue scale (VAS)) were assessed; time for placement between removal of the face mask and connection of the laryngeal mask to the breathing system was measured. Adequate ventilation was always obtained after placement of the intubating laryngeal mask, whereas ventilation was adequate in 22 of 25 patients after placement of the conventional laryngeal mask. Placement of the intubating laryngeal mask was significantly easier (P < 0.001; 95% confidence intervals (CI) for median difference 8-31 mm in VAS) and faster (P << 0.001; 95% CI for mean difference 3.2-6.2 s) than that of the conventional mask.

Adolescent↗
PubMed1999

Re-evaluation of appropriate size of the laryngeal mask airway.

We have assessed 32 males and 31 females in a randomized, crossover study to see if there was any difference in the correct positioning of the laryngeal mask, optimal ventilation (defined as no gas leak around the mask at an airway pressure of 18 cm H2O) and cuff visibility between sizes 4 and 5 masks in males and sizes 3 and 4 in females. The position of the mask in relation to the glottis was assessed using a fibreoptic bronchoscope. There was no significant difference in correct positioning between the two sizes in either sex. Gas leak was significantly less frequent for a larger than a smaller mask (P < 0.01 for both sexes), whereas the cuff was more often seen in the mouth with larger masks (P < 0.02 for males and P < 0.01 for females). Therefore, larger masks (size 4 in females and size 5 in males) provided a better seal than smaller sizes without worsening the relative position of the mask to the glottis; however, the larger mask came up within the mouth more often, which could interfere with tonsillectomy and could increase the risk of sore throat or lingual nerve damage.

Adult↗
PubMed1999

Naloxone inhibits gastric emptying in the rat.

UNLABELLED: Naloxone is generally considered to be a pure antagonist, but it may produce several behavioral effects, such as hyperalgesia or stimulation of respiration. We studied the effect of naloxone on gastric emptying and gastrointestinal transit in rats. Six to eight Wistar rats (200-250 g) were used for each experiment. Either saline or naloxone (0.01-10 mg/kg) was injected intraperitoneally at 0 min. At 30 min, radiolabeled saline or milk 1 mL was infused into the stomach. At 60 min, gastric emptying and gastrointestinal transit were calculated by measuring the radioactivity in the gastrointestinal tract. Naloxone significantly inhibited gastric emptying of saline (P = 0.002) and of milk (P < 0.05), but not the gastrointestinal transit of either (P > 0.05). Gastric emptying of saline showed a significant peak (P < 0.05) in the dose-response curve at 0.7 mg/kg. Therefore, naloxone significantly inhibits gastric emptying of saline and milk, but not the gastrointestinal transit of either. IMPLICATIONS: Although naloxone is generally considered to be a pure opioid receptor antagonist, it delays gastric emptying of saline or milk, as does morphine in the rat. However, it is uncertain from our results whether naloxone inhibited gastric emptying by antagonizing the effects of endogenous opioids.

Animals↗