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Biomedical subjects

Y Iwai

Publications and source records attributed to Y Iwai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Actinoplanes capillaceus sp. nov., a new species of the genus Actinoplanes.

Two motile actinomycete strains, K95-5561T and K95-5562, were isolated from a soil sample collected at Sayama City, Saitama Prefecture, Japan. They produced bell shaped spore vesicles (sporangia) with hairy surfaces on substrate hyphae. When released into water, the sporangiospores became motile by a tuft of polar flagella. The chemotaxonomic and morphological characteristics together with 16S rRNA gene sequence data indicated that the two isolates belonged to the genus Actinoplanes. The two strains were assigned to a single species on the basis of phenotypic, notably cultural, morphological and physiological characteristics, and DNA-DNA pairing data. The two strains were distinguished from representatives of all validly described species of Actinoplanes using a combination of genotypic and phenotypic properties. It is, therefore, proposed that strains K95-5561 and K95-5562 be recognized as a new species of the genus Actinoplanes with the name Actinoplanes capillaceus sp. nov. The type strain of the species is strain K95-5561T (=JCM 10268T =IFO 16408T). The invalidly proposed species 'Ampullariella cylindrica', 'Ampullariella pekinensis' and 'Ampullariella pilifera' were assigned to Actinoplanes capillaceus on the basis of genotypic and phenotypic data.

DNA, Ribosomal↗
PubMed2000

Spontaneous coughing up of a polyp.

We report the case of an 18-year old female with right lower lobe atelectasis, who was admitted to our hospital because of a nonproductive cough. She underwent fiberoptic bronchoscopy that revealed a peduncular polyp in the right truncus intermedius or middle bronchus. Before admission for laser polypectomy, she spontaneously coughed up the tissue mass, and the right lower lobe atelectasis disappeared. We report a rare case of 'autopolypectomy' of a bronchial adenoma.

Adenoma↗
PubMed2000

Argadin, a new chitinase inhibitor, produced by Clonostachys sp. FO-7314.

A new chitinase inhibitor, designated as argadin (1), was isolated from the cultured broth of a fungal strain FO-7314. The strain was identified as Clonostachys sp. from the morphological characteristics. Argadin was purified from the cultured mycelium by a combination of cation exchange, adsorption and gel filtration chromatographic methods. The structure of argadin was elucidated as cyclo(Nomega-acetyl-L-arginyl-D-prolyl-homoseryl-histidyl-L- 2-aminoadipyl) in which homoseryl gamma-methylene bonded to histidyl alpha-amino residue. The IC50 value of argadin against Lucilia cuprina (blowfly) chitinase was 150 nM at 37 degrees C and 3.4 nM at 20 degrees C. Argadin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.

Animals↗
PubMed2000

Arisugacins C and D, novel acetylcholinesterase inhibitors and their related novel metabolites produced by Penicilium sp. FO-4259-11.

The mutant of Penicillium sp. FO-4259, an arisugacins A and B producing strain, was found to produce a series of metabolites, designated arisugacins C, D, E, F, G and H, which were structurally related to arisugacins A and B. These compounds were isolated from the culture broth and the physico-chemical and biological properties were examined. The IC50 values of arisugacins C and D against acetylcholinesterase (AChE) were 2.5 microM and 3.5 microM, respectively. However arisugacins E, F, G and H did not inhibit AChE at 100 microM. Though they showed only weak or no activity against AChE compared with arisugacins A and B, they may be useful for the study of the structure-activity relationship.

Cholinesterase Inhibitors↗
PubMed2000

Argifin, a new chitinase inhibitor, produced by Gliocladium sp. FTD-0668. I. Taxonomy, fermentation, and biological activities.

A new chitinase inhibitor, named argifin, was isolated from the cultured broth of a fungal strain FTD-0668. The strain was identified as Gliocladium sp. from morphological characteristics. The IC50 value of argifin against Lucilia cuprina chitinase was 3.7 microM. Argifin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.

Animals↗
PubMed2000

Argifin, a new chitinase inhibitor, produced by Gliocladium sp. FTD-0668. II. Isolation, physico-chemical properties, and structure elucidation.

A new chitinase inhibitor, named argifin, was isolated from the cultured broth of a fungal strain Gliocladium sp. FTD-0668. Argifin was purified from the cultured mycelium by the combination of cation exchange, anion exchange, adsorption, and gel filtration chromatographic methods. The structure of argifin was elucidated as cyclo(N(omega)-(N-methylcarbamoyl)-L-arginyl-N-methyl-L-phenylalan yl-beta-L-aspartyl-beta-L-aspartyl-D-alanyl) by NMR experiments and other spectroscopic analyses.

Chitinases↗
PubMed2000

[Cervical pyogenic spondylodiscitis: 4 cases report and a review of the literature].

We report 4 cases of cervical spondylodiscitis presenting neurological and/or neuroradiological abnormalities. Such a lesion is rare in the cervical spine of adults, but should be suspected when the patient has radiculopathy and/or myelopathy associated with inflammatory signs. We discussed the clinical characteristics and the procedures of the diagnosis and treatment of cervical spondylodiscitis. Early and definitive diagnosis can be achieved by cervical X-ray, MR imaging and biopsy. It is very important to evaluate the pyogen for the lesion by needle biopsy. When the patient has the compression of the spinal cord and/or nerve roots and the neurological findings of radiculopathy and/or myelopathy, surgical exploration and decompression of the spinal cord and/or nerve roots should be carried out as soon as possible. Anterior debridement and fusion should be performed using the effective antibiotics. We were able to achieve good prognosis by treatment following this procedure of diagnosis in the four cases of cervical spondylodiscitis mentioned.

Adult↗
PubMed2000

[The resistance of recent clinical isolates against isepamycin, other aminoglycosides and injectable beta-lactams].

Clinical isolates collected from clinical facilities across Japan in 1998 were tested against five aminoglycosides and three beta-lactams. The resistance of 50 strains each of methicillin sensitive Staphylococcus aureus, methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter sp., Serratia sp., Pseudomonas aeruginosa and Proteus sp. (P. mirabilis 25 strains and P. vulgaris 25 strains) to the aminoglycosides isepamicin (ISP), amikacin (AMK), gentamicin, tobramycin and dibekacin, and to the beta-lactams imipenem, ceftazidime and piperacillin (all three known to be effective against P. aeruginosa) were investigated using a micro liquid dilution method with the following results: 1. ISP was effective against all strains except for 14% of MRSA, 2% of Proteus sp., and 4% of P. aeruginosa. 2. Six strains of MRSA were resistant to all eight drugs; however, in these cases ISP exhibited a relatively low minimum inhibitory concentration (MIC) compared to the other compounds. 3. Four strains of MRSA were resistant to all drugs except ISP. MRSA was the only isolate to demonstrate a resistance to seven or more drugs. 4. Twenty-one strains of MRSA and 1 strain of P. aeruginosa were resistant to six drugs; however, all of these were susceptible to both ISP and AMK. 5. Against all strains tested, ISP generally exhibited a lower MIC compared to AMK. These results suggest that, even ten years after its entering the market, ISP is still an aminoglycoside having a high anti-bacterial activity against a wide range of clinical isolates.

Amikacin↗
PubMed2000

[Rerupture mechanism of ruptured intracranial dissecting aneurysm in the vertebral artery following proximal occlusion].

Proximal occlusion is commonly employed to prevent rebleeding of intracranial dissecting aneurysms of the vertebral artery (VA), but rebleeding sometimes occurs. To determine the cause of such rebleeding we reviewed nine cases, including eight reported in the literature and one treated at our hospital. We classified the techniques used to proximally occlude the VA into two types. In Type I, occlusion is performed immediately proximal to the aneurysm so that there are no perforating arteries or the posterior inferior cerebellar artery (PICA) between the clip and the aneurysm. In Type II, occlusion is performed proximal to the PICA so postoperative retrograde flow persists from the contralateral VA through the aneurysm into the ipsilateral PICA. Among the four Type I cases reviewed, it was found that the interval between occlusion and rebleeding was very short: three developed rebleeding within four hours of occlusion, and the fourth showed rebleeding on the fourth day. In the five Type II patients, rebleeding occurred more than four days (mean 15.2 days) after occlusion. It is thought that in Type I occlusion, retrograde flow into the aneurysm immediately after occlusion may raise the intraaneurysmal pressure enough to cause rerupture within just a few hours of occlusion. In Type II occlusion, postoperative retrograde flow through the aneurysm into the ipsilateral PICA exists, so the intraaneurysmal pressure is not likely to rise as rapidly, with the result that rebleeding occurred after more than four days probably due to recurrence of dissection. The short interval between proximal occlusion and rebleeding, especially in Type I cases, suggests that postoperative angiography is only of limited usefulness in evaluating the possibility of rebleeding. The mortality rate reported for cases with reruptured vertebral dissecting aneurysms after proximal occlusion is very high (55.6%). These data indicate that surgical trapping or endovascular intraluminal occlusion, which is difficult to perform in some patients, should be considered the most suitable procedure from the view point of preventing postoperative rebleeding.

Cerebral Hemorrhage↗
PubMed2000

[Gamma knife radiosurgery for skull base meningiomas: the treatment results and patient satisfaction expressed in answers to a questionnaire].

Skull base meningiomas can be treated by radiosurgery with low morbidity. We evaluated the effectiveness of gamma knife radiosurgery for skull base meningiomas. We also evaluated patient satisfaction through answers to a questionnaire. We treated 77 patients of skull base meningiomas using gamma knife radiosurgery from January 1994 to June 1998. Among these patients, 73 patients were able to be followed up from 6 to 60 months (average 25 months). The diagnosis was made by operations on 39 patients (53%), and on magnetic resonance imagings in 34 patients (47%). 21 patients (28.7%) had residual tumors after operations and 18 patients (24.3%) had recurrence after operations. 40% of neurological deficits occurred after previous operations and 20% of the patients were asymptomatic. The locations of the tumors were mainly the cavernous sinus region in 35 patients and the petroclival region in 20 patients. The tumor sizes were 8.6 to 58.3 mm (average 24.7 mm) and five cases of tumors with a mean diameter above 40 mm were treated by two-staged radiosurgery. Treatment volume was 0.3 to 31 ml (average 9.8 ml). The treatment dose was 8 to 16 Gy (average 11.2 Gy) at the tumor margin. The tumor decreased in size in 50 patients (68%) and was unchanged in 20 patients (28%) and we were able to achieve 96% tumor growth control. The clinical symptoms improved in 22 patients (30.1%) and were unchanged in 47 patients (64.4%) and only 4 patients (5.5%) showed deterioration. 50 patients (68%) felt clinical improvement and only 3 patients (4%) sensed deterioration. 58 patients (79%) were able to continue their previous work. Gamma knife radiosurgery has a very low morbidity rate and enables good tumor control, and patients with skull base meningiomas express satisfaction with the treatment results.

Adolescent↗
PubMed2000

[Treatment of renal cell carcinoma extending into the right atrium with extra-corporeal circulation using high-grade hypothermia: a case report].

A 68-year-old woman underwent surgical treatment for renal cell carcinoma associated with tumor thrombus extending into the right atrium. Although the tumor thrombus reached the level of the right atrium, there were no other apparent metastases. Combination therapy with interferon alfa plus tegafur/uracil (UFT) was attempted with the expectation of reducing the tumor thrombus, but there was no change. Successful management was achieved with right radical nephrectomy, right auriculotomy, and partial cavectomy using cardiopulmonary bypass under high-grade hypothermia. After removal of the tumor and thrombus, blood loss was 13,900 ml during the patient's recovery. She had mild heart failure for about two weeks after the operation, but recovered. She was discharged on the 40th day after the operation. Proper preparation for blood transfusion is the key point of this operation.

Aged↗
PubMed2000

[Urethral diverticula surrounding the urethra in women: report of 2 cases].

We report two cases of female urethral diverticula. A 49-year-old woman (case 1) complained of perineal pain when she voided urine. A 36-year-old woman (case 2) complained of perineal pain. In both cases, intravenous pyerography and urethrography revealed diverticula around their urethra, and we diagnosed them with urethral diverticula which surrounded their urethra by magnetic resonance imaging. We treated them by transvaginal diverticulectomy. Case 2 was successfully treated, but the diverticulum recurred after one year in case 1. There are over 200 reported cases of female diverticula in the Japanese literature, but a urethral diverticulum surrounding the urethra is rare.

Adult↗
PubMed2000

[Dural arteriovenous fistulae in the anterior cranial fossa--report of three cases].

Dural arteriovenous fistulae (DAVF's) in the anterior cranial fossa are uncommon. We encountered three patients with DAVF's in the anterior cranial fossa and reviewed the pertinent literature with regard to the etiology. All patients are middle-aged males. Two of three patients had massive intracranial hemorrhage, subarachnoidal hemorrhage in one and subdural hemorrhage in the other. One patient had a ruptured middle cerebral artery aneurysm and DAVF at the anterior cranial fossa was detected only incidentally. Angiographically, blood supplies were from the bilateral enlarged anterior ethmoidal arteries. These drained into the superior sagittal sinus via dilated frontal cortical veins. In all the patients, coagulation of the fistulous connections was carried out and the postoperative courses were uneventful. Angiographies revealed complete disappearance of the DAVF's. In conclusion, compared to cases of DAVF's in the other locations, DAVF's of the anterior cranial fossa are more likely to be brought on by sudden massive intracranial hemorrhage, and should be treated, even if asymptomatic, at the time of diagnosis. Surgical obliteration of the fistulous connection is sufficient treatment for DAVF in the anterior cranial fossa. Literature review strongly suggests that DAVF's involving the anterior cranial fossa are acquired lesions.

Aged↗
PubMed2000

[The limitations of three-dimensional CT angiography (3D-CTA) in the diagnosis of cerebral aneurysms].

OBJECT: The purpose of this study is to show some limitations of 3D-CTA to diagnose cerebral aneurysms. METHODS: Sixteen saccular aneurysms less than 10 mm in diameter were included. Large and complicated aneurysms were excluded. RESULTS: Although information about perforating arteries from the posterior cerebral artery is very important for surgery of basilar bifurcation aneurysms, 3D-CTA could not delineate the perforating arteries. A small posterior communicating artery (Pcom.A.) was not detected, and it was very difficult to differentiate infundibular dilatation of the Pcom. A. from an aneurysm. A small aneurysm of the distal middle cerebral artery could not be detected. Flow direction can not be determined by 3D-CTA, and nor could the side of the neck of the anterior communicating artery aneurysm be determined. Fenestration of the anterior communicating artery and the origin of the triple anterior cerebral artery were both misdiagnosed as anterior communicating artery aneurysms. CONCLUSION: It is premature to consider 3D-CTA as a replacement for conventional angiography.

Adult↗
PubMed1999

Daidzein and genistein but not their glucosides are absorbed from the rat stomach.

Absorption of isoflavone aglycones and glucosides was compared in rats. Daidzein, genistein, daidzin and genistin were orally administered at a dose of 7.9 micromol/kg in 25 mM Na2CO3 and next their metabolite concentration in blood plasma was monitored for 30 min. After isoflavone glucosides administration, their metabolites appeared in plasma with a few minutes delay as compared to aglycones, which suggested that aglycones, but not glucosides, were absorbed already in the rat stomach. This observation was confirmed when absorption site was restricted solely to the stomach and absorption was shown to be independent of the vehicle pH used for administration.

Absorption↗
PubMed1999

Expression of vascular endothelial growth factor in exuberant tracheal granulation tissue in children.

Prolonged tracheotomy and endotracheal intubation often induce symptoms of airway obstruction and delay decannulation and extubation. Bronchoscopic examination of patients undergoing these treatments usually shows the presence of exuberant (pseudopapillary or nodular) granulation tissue occupying the airway lumen. An immunohistochemical analysis was undertaken of vascular endothelial growth factor (VEGF) expression in exuberant tracheal granulation tissue (n=17) obtained from children treated with prolonged tracheotomy or endotracheal intubation. Increased levels of VEGF protein and mRNA were expressed mainly by tracheal epithelial cells that migrated to cover the granulation tissue and partly by pericapillary macrophages in this tissue, whereas normal tracheal epithelium did not express VEGF. The VEGF expression level correlated significantly with the severity of the exuberant granulation tissue response (p=0.0018). As VEGF induces angiogenesis and vascular permeability, characteristics of granulation tissue, and plays a pivotal role in granulation tissue development, enhanced VEGF expression may be involved in the development of exuberant tracheal granulation tissue.

Adolescent↗
PubMed1999

Gamma knife surgery for skull base meningiomas. The effectiveness of low-dose treatment.

BACKGROUND: The surgical removal of skull base meningiomas has a high morbidity rate, even by modern microsurgical standards. We evaluated the results of gamma knife surgery for skull base meningiomas using a relatively low radiation dose for the tumor margins. METHODS: We reviewed 24 cases of skull base meningiomas during a 30-month period. The locations of the tumors were the petroclival region in 11 cases, the cavernous sinus region in 9 cases, and the cerebellopontine angle region in 4 cases. Eight patients (33%) had been operated on previously and fourteen patients (67%) had been treated by neuroimaging. The marginal doses for the tumors were 8 Gy to 15 Gy (median, 10.6 Gy). A large petroclival tumor 58 mm in diameter was treated with a staged treatment protocol with a 6-month interval between treatments. RESULTS: Tumor regression was observed in 46% of the patients imaged during the follow-up period (median, 17.1 months). No patients revealed tumor growth in the follow-up period (100% tumor control rate). Eleven patients (46%) had improved clinically by the time of the follow-up examinations. Preexisting cranial nerve deficit in one patient worsened because of radiation injury. CONCLUSION: Although a longer follow-up period is required, the relatively low minimum tumor radiation dose treatment for skull base meningiomas using a gamma knife seems to be an effective treatment with low morbidity.

Adult↗