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F Iwamoto

Publications and source records attributed to F Iwamoto.

6 recordsLinked to original sources
PubMed2001

Intraoperative ultrasound arteriography with the "Coded Harmonic Angio" technique. Report of three cases.

The result of combining the ultrasound Coded Excitation method and an ultrasound contrast agent (UCA), the Coded Harmonic Angio (CHA) technique provides arterial images with exceptional spatial, temporal, and contrast resolution that are comparable to those produced by conventional digital subtraction angiography. The authors report on their experience with intraoperative ultrasound arteriography performed using the transdural CHA technique in three patients: one harboring a meningioma, another with a middle cerebral artery aneurysm, and a third with an arteriovenous malformation. The present study demonstrates how intraoperative cerebral ultrasound arteriography can be applied to assess the adequacy of neurovascular procedures without the presence of an experienced operator.

Aged↗
PubMed1997

Isolation of freeze-tolerant laboratory strains of Saccharomyces cerevisiae from proline-analogue-resistant mutants.

Since some amino acids, polyols and sugars in cells are thought to be osmoprotectants, we expected that several amino acids might also contribute to enhancing freeze tolerance in yeast cells. In fact, proline and charged amino acids such as glutamate, arginine and lysine showed a marked cryoprotective activity nearly equivalent to that of glycerol or trehalose, both known as major cryoprotectants for Saccharomyces cerevisiae. To investigate the cryoprotective effect of proline on the freezing stress of yeast, we isolated proline-analogue-resistant mutants derived from a proline-non-utilizing strain of S. cerevisiae. When cultured in liquid minimal medium, many mutants showed a prominent increase, two- to approximately tenfold, in cell viability compared to the parent after freezing in the medium at -20 degrees C for 1 week. Some of the freeze-tolerant mutants were found to accumulate a higher amount of proline, as well as of glutamate and arginine which are involved in proline metabolism. It was also observed that proline-non-utilizer and the freeze-tolerant mutants were able to grow against osmotic stress. These results suggest that the increased flux in the metabolic pathway of specific amino acids such as proline is effective for breeding novel freeze-tolerant yeasts.

Amino Acids↗
PubMed1997

Idiopathic cranial pachymeningoencephalitis focally affecting the parietal dura mater and adjacent brain parenchyma: case report.

OBJECTIVE AND IMPORTANCE: Cranial pachymeningitis is a typically diffuse granulomatous disease, which often affects the tentorium and falx. We report a rare case of idiopathic cranial pachymeningoencephalitis focally affecting only the left parietal dura mater and adjacent inferior parietal lobule. CLINICAL PRESENTATION: A 46-year-old woman, with no history of disease, suddenly had a generalized convulsion. A gadolinium-enhanced T1-weighted magnetic resonance image showed homogeneously stained meninges extending to the cortical parenchyma with marked perifocal edema. The thickened dura was visualized as a hypointense area on a T2-weighted magnetic resonance image. INTERVENTION: The patient underwent successful en bloc excision of the mass involving the dura mater and adjacent brain parenchyma. Histological examination of the dura mater revealed large numbers of chronic and acute inflammatory cells. These cells were also present in the subarachnoid and Virchow-Robin spaces and part of the brain parenchyma in the resected cortex. After the operation, the patient experienced no neurological deficits or recurrent mass for 10 months. CONCLUSION: Early diagnosis of pachymeningitis using magnetic resonance imaging is important for the treatment of pachymeningoencephalitis, because diffuse involvement of the dura mater and brain parenchyma can make en bloc excision difficult.

Brain Edema↗
PubMed1992

[Identification of optical isomers of methamphetamine and its application to forensic medicine].

In order to identify optical isomers (d and l-) of methamphetamine (MAMP), GC-MS analysis using optically resolvable reagent of N-trifluoroacetyl-L-prolyl chloride (L-TPC) and HPLC analysis using chiral cellulose-based columns were compared. In analysis of d- or l-MAMP (M) of TPC (T) derivatives by the GC-MS, contrary to the expectation that only d(M)-L(T) or l(M)-L(T) could be detected chemically, two diastereomers of d(M)-L(T) and d(M)-D(T) for d-MAMP and two of l(M)-L(T) and l(M)-D(T) for l-MAMP were demonstrated respectively. This results was attributed to a small percentage of D-TPC present in L-TPC. For racemic (dl)-MAMP, none of these four isomers could be individually isolated, and they were detected as two overlapping peaks. In the HPLC analysis using chiral columns, d- and l-isomers of MAMP and amphetamine (AMP) could be clearly isolated with merely one analytical procedure, and the l/d ratio was possible to calculate with facility. From the rats urine administered d- or l-MAMP, only the corresponded optically active form of the administered drug was detected, and when racemic (dl)-MAMP was administered, d-MAMP, l-MAMP and their metabolites AMP were distinctly detected. The l/d ratio calculated from amount of MAMP and AMP excreted in rat urine within 24 hr was not in accordance with that of the administered dl-MAMP (l/d = 1.01): the l/d ratio was 0.45 for MAMP and 0.58 for AMP, and 0.50 for the total of MAMP and AMP. The similar results were observed in case of racemic (dl)-AMP. From several human specimens obtained from the cadavers dead by MAMP poisoning, only d-MAMP and the metabolite d-AMP were detected, and neither l-MAMP or l-AMP were demonstrated. In particular, a high concentration of d-MAMP was detected in gastric contents, brain, lung and liver. From the MAMP powder in possession, only d-MAMP was detected. These results suggest that this chiral column-HPLC procedure could be applied to medicolegal practice and forensic scientific investigation.

Animals↗