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Takeshi Higuchi

Publications and source records attributed to Takeshi Higuchi.

10 recordsLinked to original sources
PubMed2005

In vitro activity of beta-lactams and quinolones against AmpC beta-lactamase-producing Escherichia coli.

We studied the antimicrobial susceptibility of AmpC beta-lactamase-producing Escherichia coli isolates collected at ten medical institutions in the Kinki area of Japan during a 6-month period (November 2002 through April 2003). Of 2845 E. coli isolates tested, 29 (1.0%) showed a minimum inhibitory concentration (MIC) for cefazolin of more than 8 microg/ml and were three-dimensional extract test positive. In standard inoculum susceptibility tests against these 29 strains, the MIC90s for the four carbapenems tested ranged from 0.06 microg/ml to 0.5 microg/ml, and these compounds were more active than the other beta-lactams, with meropenem being the most active. The MIC90s for beta-lactams, except carbapenems, ranged from 4 microg/ml to 32 microg/ml, with cefepime being the most active. In high inoculum susceptibility tests against these strains, the MIC90s for the four carbapenems and cefepime were 8 microg/ml or less, and these compounds were more active than other beta-lactams. The MIC90s for beta-lactams, except carbapenems and cefepime, were 32 microg/ml or more. The MIC90s for the five quinolones tested ranged from 4 microg/ml to 16 microg/ml, and the order of increasing susceptibility was ciprofloxacin > levofloxacin, gatifloxacin and pazufloxacin > prulifloxacin.

Anti-Bacterial Agents↗
PubMed2005

Spontaneous formation of polymer nanoparticles by good-solvent evaporation as a nonequilibrium process.

In recent years, polymer nanoparticles have been investigated with great interest due to their potential applications in the fields of electronics, photonics, and biotechnology. Here, we report the spontaneous formation of polymer nanoparticles from a clear solution containing a nonvolatile poor solvent by slow evaporation of a volatile good solvent. During evaporation of the good solvent, the solution gradually turns turbid. After evaporation, polymer nanoparticles of homogeneous shape and size are dispersed in the poor solvent. Homogeneous nucleation and successive growth of polymer particles takes place during the dynamic nonequilibrium process of solvent evaporation. The size of the particles, ranging from tens of nanometers to micrometer scale, depends on both polymer concentration and the solvent mixing ratio. Because of the physical generality of the particle formation mechanism, this procedure is applicable to a wide variety of polymers with suitable combinations of solvents. Here, we also show unique features, surface structures and surface properties of polymer nanoparticles prepared by this method.

Chemical Precipitation↗
PubMed2004

Diagnosis of peripheral nerve sheath tumors around the pelvis.

OBJECTIVE: To distinguish between benign and malignant peripheral nerve sheath tumors around the pelvis. METHODS: A retrospective study of 30 patients with benign and malignant peripheral nerve sheath tumors located around the pelvis was performed. Clinical, imaging and histological features of 19 benign and 11 malignant peripheral nerve sheath tumors around the pelvis were reviewed retrospectively. RESULTS: Nearly all patients exhibited pain at presentation in cases involving both benign and malignant tumors. Although tumor size, duration of symptoms and presence of sensory disturbance possessed little value in differential diagnosis, severe motor weakness was observed exclusively in patients presenting with malignant tumors. On CT or MRI, central enhancement was apparent in 11 of the 19 benign tumors; in contrast, central enhancement was evident in one of the 11 malignant tumors. Fine needle aspiration cytology was performed in 11 tumors; correct diagnosis was achieved in four tumors. Core needle biopsy was performed in five tumors, all of which were correctly diagnosed with no neurological deficits. Immunohistochemically, all benign tumors were diffusely positive for S-100 protein, whereas malignant tumors were negative or focally positive for S-100 protein. Ki-67 index was less than 4% in all benign tumors; additionally, this index was 7-36% in malignant tumors. CONCLUSION: Central enhancement pattern on imaging studies strongly suggests a benign tumor; in contrast, severe motor weakness suggests malignant lesions. Core needle biopsy was reliable with respect to preoperative diagnosis.

Adolescent↗
PubMed2004

[The value of proper sputum collection instruction in detection of acid-fast bacillus].

PURPOSE: This study was conducted to assess clinically whether intervention with instruction applying respiratory rehabilitation method for expectorating sputum was useful or not to obtain more suitable sputum for smear examination of acid-fast bacilli. SUBJECT: All specimens examined were sputa obtained from 163 patients without the instruction group and 161 patients with the instruction group, who visited our outpatients clinic during one year from September 1, 2000 to August 31, 2001 and the following one year, respectively. METHOD: Gross appearance of the sputum according to Miller & Jones' classification (M1, M2, P1-P3) and smear positive rate by fluorescence staining method after N-Acetyl-L-cysteine-NaOH treatment and centrifugation were compared between the two groups. RESULTS: M1 and P1 sputa were 21.5% and 21.5% in the no instruction group, while those were 8.1%, 36.6% in the instruction group. Difference in M2, P2 and P3 sputa were not significant between the groups. Smear positive rate was 10.4% in the no instruction group, while it was 21.1% in the instruction group. According to gross appearance of M2, P1 and P2, positive rate was 11.1%, 11.4% and 30.8% in the no instruction group, and 17.7%, 28.8%, and 26.3% in the instruction group. Chest roentogenographic findings judged by type (cavitary and non-cavitary) and extent of the pulmonary lesions of these smear positive cases (17 in the no instruction group and 34 with the instruction group), revealed that the no instruction group consisted of more predominantly severer disease with cavity and moderately or far advanced lesions as compared with the instruction group. CONSIDERATION: We could exclude that the difference in gross appearance and smear-positive rate of the sputum specimen between groups without and with the instruction might be due to differences in disease severity between the two groups with and without the instruction. CONCLUSION: The instruction for sputum expectoration seems to be useful to increase positive rate in the smear examination of acid-fast bacilli.

Female↗
PubMed2004

[Direct detection of rifampicin resistant Mycobacterium tuberculosis in sputum by line probe assay (LiPA)].

OBJECTIVES: To examine the direct detection of rifampicin (RFP)-resistant Mycobacterium tuberculosis in sputum by Line Probe Assay (LiPA). MATERIALS AND METHODS: We collected 130 sputa and analyzed both by LiPA and the Amplicor M.tuberculosis assay. For culture-positive samples, RFP resistance testing was performed and compared with the results by LiPA. RESULTS: Eighty two out of 84 M. tuberculosis samples were detected by LiPA and all of 10 Mycobacteria other than M. tuberculosis (MOTT) samples and 36 negative samples were negative by LiPA. The detection rate is same as Amplicor. For culture-positive samples, LiPA showed mutation pattern for all of 22 RFP-resistant strains and wild type pattern for 19 of 20 RFP-sensitive strains. The one remaining showed mixed pattern of wild type and mutation pattern. CONCLUSION: The use of LiPA for sputum coould enable early detection of RFP-resistant tuberculosis and seems to be useful for the control of tuberculosis.

Antibiotics, Antitubercular↗
PubMed2003

Presacral multiple cellular schwannomas.

STUDY DESIGN: Case report. The authors documented a patient presenting with multiple cellular schwannomas along the sciatic nerve. The patient had no stigmas of neurofibromatosis. Thirteen tumors were resected via both anterior and posterior approaches. OBJECTIVES: To point out that presacral cellular schwannoma can display multiple occurrences. SUMMARY OF BACKGROUND DATA: Cellular schwannoma, which is a well-recognized variant of benign schwannoma, is often misdiagnosed as sarcoma. The tumor is usually a solitary lesion. MATERIALS AND METHODS: Medical history, physical findings, imaging features, and histologic findings were reviewed in a case of multiple cellular schwannomas in the presacral regions. RESULTS: A 39-year-old woman without any evidence of neurofibromatosis underwent removal of presacral multiple tumors along the sacral nerve root. Nineteen years after the surgery, the tumors recurred with multiple fashion. Thirteen tumors were resected via both anterior and posterior approaches. Immunohistochemical analysis of S-100 protein and Ki-67 were beneficial with respect to differentiation of cellular schwannoma from malignant peripheral nerve sheath tumor. CONCLUSIONS: The present case illustrated that multiple cellular schwannomas can develop in nonneurofibromatosis patients.

Adult↗
PubMed2003

Activating Gs alpha mutation at the Arg201 codon in liposclerosing myxofibrous tumor.

Liposclerosing myxofibrous tumor (LSMFT) is a benign fibro-osseous lesion that is characterized by mixture of histologic elements including lipoma, fibroxanthoma, myxoma, ischemic ossification, and fibrous dysplasia (FD)-like features. These tissue components are seen in the original reports of FD; however, the relationship between LSMFT and FD is not clear. Point mutation of the alpha subunit of G protein (Gs alpha), which increases cyclic adenosine monophosphate formation, has been recognized as the cause of McCune-Albright syndrome as well as polyostotic and monostotic FD of bone. Gs alpha mutation at the Arg201 codon in 2 patients of LSMFT was demonstrated in the present study. Although direct sequencing analysis using the fresh-frozen materials could not detect the mutation, the polymerase chain reaction fragmentation length polymorphism (PCR-RFLP) disclosed the missense point mutation Gs alpha at the Arg201 codon in 2 cases involving LSMFT. This result strongly suggests that a subset of LSMFT is a variant form of FD.

Aged↗
PubMed2002

Plasmid-encoded asp operon confers a proton motive metabolic cycle catalyzed by an aspartate-alanine exchange reaction.

Tetragenococcus halophila D10 catalyzes the decarboxylation of L-aspartate with nearly stoichiometric release of L-alanine and CO(2). This trait is encoded on a 25-kb plasmid, pD1. We found in this plasmid a putative asp operon consisting of two genes, which we designated aspD and aspT, encoding an L-aspartate-beta-decarboxylase (AspD) and an aspartate-alanine antiporter (AspT), respectively, and determined the nucleotide sequences. The sequence analysis revealed that the genes of the asp operon in pD1 were in the following order: promoter --> aspD --> aspT. The deduced amino acid sequence of AspD showed similarity to the sequences of two known L-aspartate-beta-decarboxylases from Pseudomonas dacunhae and Alcaligenes faecalis. Hydropathy analyses suggested that the aspT gene product encodes a hydrophobic protein with multiple membrane-spanning regions. The operon was subcloned into the Escherichia coli expression vector pTrc99A, and the two genes were cotranscribed in the resulting plasmid, pTrcAsp. Expression of the asp operon in E. coli coincided with appearance of the capacity to catalyze the decarboxylation of aspartate to alanine. Histidine-tagged AspD (AspDHis) was also expressed in E. coli and purified from cell extracts. The purified AspDHis clearly exhibited activity of L-aspartate-beta-decarboxylase. Recombinant AspT was solubilized from E. coli membranes and reconstituted in proteoliposomes. The reconstituted AspT catalyzed self-exchange of aspartate and electrogenic heterologous exchange of aspartate with alanine. Thus, the asp operon confers a proton motive metabolic cycle consisting of the electrogenic aspartate-alanine antiporter and the aspartate decarboxylase, which keeps intracellular levels of alanine, the countersubstrate for aspartate, high.

Alanine↗
PubMedDate not supplied

Clinical and imaging features of distended scapulothoracic bursitis: spontaneously regressed pseudotumoral lesion.

OBJECTIVE: To describe clinical and imaging findings of distended scapulothoracic bursitis without scapular snapping, which is often confused with a soft tissue tumor. METHODS: Nine patients (6 male, 3 female; age range: 50-73 years; mean age = 67 years) with distended scapulothoracic bursitis diagnosed by clinical and magnetic resonance (MR) imaging findings were studied. The results of a histologic examination were available in 1 case. RESULTS: All patients presented with painless palpable masses below the scapula, and the initial diagnoses were soft tissue tumors. On MR images, the lesions were 5.5 to 12 cm in maximum diameter (mean = 7.7 cm) and well-demarcated cystic masses situated in the subscapular region between the serratus anterior and the chest wall. There was no solid portion on the cyst walls. The findings of hemorrhage within the bursae were present in all cases. Every mass regressed in size spontaneously after a few to several weeks, and no lesions revealed any malignant findings of sarcomas. CONCLUSIONS: Distended scapulothoracic bursae without scapular snapping resemble soft tissue tumors. They have some specific MR findings; therefore, precise recognition of these findings is important to avoid misdiagnoses and unnecessary treatments.

Aged↗