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Biomedical subjects

N Usami

Publications and source records attributed to N Usami.

At least 19 recordsLinked to original sources
PubMed1998

[Combined rupture of trachea and esophagus following blunt trauma--a case report].

A 49-year-old man was involved in a motor vehicle crash and was admitted to a local hospital. The following day, he was transferred to our hospital because of worsening dyspnea. Initial examination revealed no subcutaneous emphysema, and chest computed tomography (CT) demonstrated no mediastinal air. A left thoracentesis tube was placed for pneumothorax, which reduced the patient's respiratory distress. He had a persistent, productive cough, which worsened when he drank water. A repeat chest CT on the fifth hospital day revealed a tracheo-esophageal fistula. Bronchoscopy and esophagoscopy confirmed the diagnosis. He underwent repair of the trachea and esophagus. The ruptured membraneous portion of the trachea was closed with interrupted sutures and covered with pedicled pericardial flap. The perforated anterior esophageal wall was sutured in layers and reinforced with a fifth intercostal muscle flap. A gastrostomy tuve was placed for feeding access. Within 6 weeks, the patient recovered completely.

Esophagus↗
PubMed1998

Synthesis and pharmacological activities in mice of halogenated delta 9-tetrahydrocannabinol derivatives.

Seven halogenated derivatives of delta 9-tetrahydrocannabinol (delta 9-THC, 1) substituted on the aromatic ring at the 2 and/or 4 position, 2 (4)-fluoro- (2), 2,4-difluoro- (3), 2-chloro- (4), 2-bromo- (5), 2,4-dibromo- (6), 2-iodo- (7) and 2,4-diiodo-delta 9-THC (8) were synthesized and pharmacological effects such as catalepsy, anticonvulsant effects, hypothermia, pentobarbital-induced sleep prolongation and locomotor activity evaluated by intracerebroventricular (i.c.v., 25 micrograms/head) and intravenous (i.v., 5 or 10 mg/kg) injections in mice. The cataleptogenic effects of 2 and 5 were about three-quarters and two-thirds, respectively, compared to those of 1 (i.v.), though other derivatives were much less active (i.c.v. and i.v.). 2 (for clonic seizures) exhibited a significant prolongation of seizure latency induced by pentylenetetrazol (i.v.). Hypothermic effects of monohalogenated derivatives were comparable to 1 when administered by i.v. injection, whereas the effects of dihalogenated derivatives of 1 were attenuated. In contrast, 3 and 8 exhibited a significant hyperthermic effect in mice. In synergy with pentobarbital, 4 and 5 exhibited a significant prolongation of sleeping time by 1.6- and 1.8-fold, respectively, compared with control (32.4 +/- 2.5 min), although other derivatives did not affect significantly the sleeping time (i.c.v.). However, by i.v. injection, 2, 4, 5 and 7 significantly prolonged pentobarbital-induced sleeping time and reduced locomotor activity. The sleep prolonging effects of 2, 4 and 7 (10 mg/kg, i.v.) were as potent as that of 1 (5 mg/kg, i.v.). 5 and 7 were the most potent derivatives among the synthetic cannabinoids examined in the present study. These results indicate that halogenation of 1 leads to modification of the pharmacological profile of THC.

Animals↗
PubMed1997

Anterior subtalar dislocation: case report.

Anterior subtalar dislocations are extremely rare. To our knowledge, only four cases have been reported in detail in the literature. A diagnosis of anterior subtalar dislocation should be confirmed by an anteroposterior view radiograph because lateral subtalar dislocation always includes some anterior displacement of the mid-foot. We report a case of anterior subtalar dislocation confirmed by both lateral and anteroposterior view radiographs and discuss its pathomechanism, diagnosis, and treatment.

Adult↗
PubMed1997

Closed complete rupture of the flexor hallucis longus tendon at the groove of the talus.

A rare case of closed complete rupture of the flexor hallucis longus tendon at its groove in the posterior process of the talus is reported in a soccer player who developed pseudarthrosis of the posterolateral tubercle of the talus after a Shepherd's fracture. Partial rupture or tenosynovitis of the flexor hallucis longus tendon at this level is well known in classical ballet dancers and soccer players. Three cases of complete rupture of the flexor hallucis longus tendon near the metatarsophalangeal joint and three under the sustentaculum tali have been reported, but there have been no reports at the groove of the talus. Repair was accomplished by tendon graft, and active flexion of the interphalangeal joint is now possible.

Adult↗
PubMed1996

Single- and double-strand breaks in pBR322 plasmid DNA by monochromatic X-rays on and off the K-absorption peak of phosphorus.

Using a synchrotron irradiation system pBR322 plasmid DNA was irradiated under vacuum by monochromatic X-rays having five specific photon energies (2.147, 2.153, 2.159, 2.168 and 2.199 keV) both on and off the K-absorption peak (2.153 keV) of phosphorus. The single- and double-strand breaks (ssb and dsb) were measured as conversions of the closed circular form of DNA (form I) to open circular (form II) and linear (form III) forms respectively. Exposures to induce one strand break per molecule were lowest at the peak (2.153 keV), and highest at 2.147 keV; the ratios were 2.7 for ssb and 3.0 for dsb. The exposures for dsb were 21-26 times higher than those for ssb. When the exposures were converted to absorbed doses in grays the absorbed doses per ssb were almost independent of photon energy. This result indicates that a certain absorbed dose was necessary to induce a ssb, regardless of whether photons were absorbed by the K-shell of phosphorus or by other shells, or by other atoms. However, the absorbed dose per dsb at 2.147 keV was 1.17 times higher than that averaged over four X-ray energies above 2-153 keV, indicating that the K-shell absorption, and the subsequent Auger event, efficiently induce dsb. The results are also discussed concerning the number of photo-absorptions of the constituent atoms per DNA strand break.

Animals↗
PubMed1996

Classification of fractures of the talus: clear differentiation between neck and body fractures.

The treatment and prognosis of neck fractures (extra-articular) and body fractures (intra-articular) of the talus are different. Ratios between neck fractures and body fractures reported by different investigators vary widely (from 6:1 to 1:1), because it is difficult to differentiate fractures crossing the anteromedial aspect of the trochlea. We examined 215 fractures of the talus. By examining the inferior surface fracture line, we found that the 61 fractures crossing the anteromedial aspect of the trochlea could be differentiated into 28 neck fractures and 33 body fractures. We suggest classifying fractures of the talus based on the inferior, not superior, surface fracture line.

Diagnosis, Differential↗
PubMed1996

Lethal effect of K-shell absorption of intracellular phosphorus on wild-type and radiation sensitive mutants of Escherichia coli.

The present study was conducted to clarify the lethality of Auger cascades induced by the K-shell photoabsorption of phosphorus in Escherichia coli. Killing of wild-type and radiation-sensitive mutants of E. coli was examined. Three x-ray energies were chosen for irradiation; at 2.153 keV: the resonance peak of K-shell photoabsorption of phosphorus; at 2.146 and 2.160 keV: off-peak. Enhancement ratio, which was defined as the ratio of the killing sensitivity of 2.153 keV to that at 2.146 keV, were 1.32 to 1.54 for examined strains. Increment of absorbed energy calculated in entire cells for 2.153 keV radiation could not explain the degree of observed enhancement of killing. Lethality of Auger cascades depended on the killing sensitivity with x-rays which did not induce Auger cascades. The lethality for wild-type was lower than that for recombination repair-deficient mutants. It was concluded that one part of damages produced by Auger cascades was repaired in wild-type strains.

Absorption↗
PubMed1996

Long-term follow up of talus fractures.

Eighty-six patients who had experienced a fracture of the talus more than 10 years previously were assessed. The fracture had occurred in the neck of the talus in 52 feet and in the body of the talus in 27 feet. The fracture was complicated by dislocation in 47 feet, and aseptic necrosis had developed in 33 feet. The outcome was rated as excellent in 20 feet, good in 43, fair in 18, and poor in 7. The cause of poor outcome in the late stage was posttraumatic osteoarthritis secondary to avascular necrosis and incongruity of the joint surface. Early active exercise without weight bearing is recommended to prevent contracture and bone atrophy due to disuse, which may promote osteoarthrosis. Arthrodesis is recommended in patients with pain because the outcome is greatly improved by arthrodesis, even when performed more than 10 years after the injury.

Adolescent↗
PubMed1995

Oxidation yield of the ferrous ion in a Fricke solution irradiated with monochromatic synchrotron soft X-rays in the 1.8-10 keV region.

The oxidation yield of ferrous ion in a Fricke solution was measured in the soft X-ray region from 1.8 to 10 keV. The standard Fricke solution was irradiated with monochromatic X-rays from synchrotron radiation. The yield decreased with decreasing X-ray energy, as several theoretical calculations have predicted. No significant changes were observed in the K-shell photo-absorption of the iron and sulphur contained in the standard Fricke solution. The high-LET nature of soft X-rays is discussed.

Dose-Response Relationship, Radiation↗
PubMed1995

Formation of carbon monoxide during mouse hepatic microsomal oxidative metabolism of cannabidiol; identification and determination.

Carbon monoxide (CO) was generated in the process of hepatic microsomal oxidative metabolism of cannabidiol (CBD). After the generated CO was reduced to methane (CH4) with a methanizer, CH4 formed was determined by gas chromatography (GC) with a flame ionization detector. After oxidation with hopcalite, CO was also identified as CO2 by gas chromatography/mass spectrometry (GC/MS). The reaction was NADPH-dependent and required molecular oxygen. It was inhibited by addition of some inhibitors of cytochrome P450-dependent monooxygenase. When CBD (191 microM) was incubated with hepatic microsomes of mice in the presence of an NADPH-generating system and oxygen, concentration of CO determined by GC was 4.7 +/- 0.5 ppm/nmol P450 in the incubation atmosphere. Pretreatment with phenobarbital (100 mg/kg, i.p. for 3d) but not 3-methylcholanthrene (80 mg/kg, i.p.) increased the CO formation 78%, while pretreatment with cobaltous chloride (40 mg/kg, i.p. for 3 d) decreased the formation 56%. When CBD was incubated under oxygen-18 gas, molecular oxygen was not incorporated into the CO molecule. 8,9-Dihydro- and 1,2,8,9-tetrahydro-CBDs also produced CO to some extent, whereas CBD monomethyl- and dimethylethers reduced the ability to produce CO. In addition, cannabidivarin and olivetol produced CO, although none of delta 9-tetrahydrocannabinol, cannabinol and d-limonene did. Thus, the resorcinol moiety of CBD is important for CO formation.

Animals↗
PubMed1995

Synthesis and pharmacological effects in mice of halogenated cannabinol derivatives.

Eight halogenated derivatives of cannabinol (CBN) substituted on the aromatic ring at the 2 and/or 4 position were synthesized and their pharmacological effects were evaluated by intracerebroventricular injection (50 micrograms/mouse) in mice, using hypothermia, pentobarbital-induced sleep prolongation, catalepsy and anticonvulsant effect as indices. The hypothermic effects of monohalogenated derivatives of CBN were comparable to that of CBN, whereas the effects of dihalogenated derivatives of CBN except for the fluorinated derivative were attenuated. In the interaction with pentobarbital, two monochlorinated derivatives exhibited a significant prolongation of sleeping time, although other derivatives did not significantly affect the sleeping time. The cataleptogenic effects of monofluoro- and 4-bromo-CBN were stronger than that of CBN. 4-Bromo-CBN exhibited a significant prolongation of seizure latency induced by pentylenetetrazol. These data suggest that halogenation of CBN modifies the pharmacological profile of the cannabinoid.

Animals↗
PubMed1994

[A case report of left limb compartment syndrome associated with laparoscopic surgery].

A 63-year-old male patient with early gastric cancer was attempted for laparoscopic wedge resection of the stomach. After the introduction of anesthesia, bandage of bilateral leg was carried out to prevent deep venous thrombosis during laparoscopic surgery. Although the procedure was converted to open surgery, the bandage has been continued throughout the surgery for 6 hours. After the operation, the swelling and severe tenderness at his left leg was observed. MRI revealed remarkable edema in left deep posterior compartment. Under diagnosis of left limb compartment syndrome, fasciotomy was carried out. Postoperatively the patient did well without any functional disturbance.

Bandages↗
PubMed1992

Mutagenic and transforming effects of soft-X-rays with resonance energy of phosphorus K-absorption edge.

Syrian golden hamster embryo (SHE) cells were exposed to synchrotron-produced monochromatic X-rays at 5.747 (2.159 keV), 5.763 (2.153 keV) and 5.779 A (2.147 keV). Although X-rays of all wavelengths induced mutations and chromatid aberrations in a dose-dependent manner, when cells were irradiated with 2.153 keV X-rays, which correspond to the resonance energy of the phosphorus K-absorption edge, the frequencies of mutation and chromatid aberration at equal dose levels were higher than for X-rays of the other wavelengths. At equal survival levels, however, there was no difference in the frequencies of mutations and chromatid aberrations in cells irradiated with soft X-rays. On the other hand, the frequency of morphological transformation in cells irradiated with 2.147 keV X-rays was higher than those irradiated with 2.153 keV and 2.159 keV X-rays. The relative biological effectiveness compared to cobalt-60 gamma-rays in morphological transformation was 2.8 for 2.147 keV, 1.1 for 2.159 keV and 1.0 for 2.153 keV at a 37% survival level.

Animals↗
PubMed1992

[Syntheses and central depressant activity in mice of uracil derivatives. Studies on development of new sedative-hypnotics. II].

Fifteen kinds of uracil derivatives, which were substituted with functional groups such as benzyl (Bn), methoxymethyl (MOM), n-propyl (Pr) or allyl (A) group at the N1 and/or N3 position of uracil, were synthesized. Sedative-hypnotic activity, pentobarbital (PB)-induced sleep prolongation and acute toxicity as indices of their pharmacological activities were evaluated using mice. Spontaneous activities of mice treated with N1-benzyluracil (N1-BnU, 7), N3-benzyluracil (N3-BnU, 8), N1,N3-dibenzyluracil (DBnU, 9), N1-benzyl-N3-allyluracil (BnAU, 14) and N1-allyl-N3-benzyluracil (ABnU, 15) were measured. Ten kinds of uracil derivatives showed hypnotic activity. ED50's values of ABnU (15) and N1-propyl-N3-benzyluracil (PrBnU, 13) were 155 and 172 mg/kg, i.p., respectively. Those effects were more potent than that of barbital (179 mg/kg, i.p.) Ten kinds of uracil derivatives tested significantly prolonged the PB-induced sleeping time. N3-BnU (8) increased the spontaneous activity of mice at a dose of 80 mg/kg, i.p., while ABnU (15) depressed the spontaneous activity at a dose of 160 mg/kg, i.p. The other compounds did not show any significant effect on the spontaneous activity of mice. LD50's values of ABnU (15), PrBnU (13) and N1-methoxy-methyl-N3-benzyluracil (MOMBnU, 11) were 199, 229 and 363 mg/kg, i.p., respectively. LD50's values of the other derivatives were more than 480 mg/kg, i.p. These results indicate that the benzyl group at the N3 position of uracil is important for exhibiting sedative-hypnotic activity of uracil derivatives, and that ABnU (15) has the most potent central depressant activity among the uracil derivatives tested.

Animals↗
PubMed1992

Inactivation action spectra of Bacillus subtilis spores with monochromatic soft X rays (0.1-0.6 nm) of synchrotron radiation.

Five types of Bacillus subtilis spores differing in DNA repair and recombinational capacities were exposed in vacuum to monochromatic soft X rays from synchrotron radiation. The inactivation rate constants were obtained from exposure-survival curves upon irradiations at 12 wavelengths in the range of 0.1000 nm (12.40 keV) to 0.6000 nm (2.066 keV). Spores of two repair-deficient strains, UVS (uvrA ssp) and UVP (uvrA ssp polA), exhibited almost equal sensitivities to those of wild-type UVR+, while those of two recombination-deficient strains, RCE (recE) and RCF (recF), exhibited higher sensitivities in the whole wavelength range. This suggested that the repair of DNA damage produced by soft X rays was dependent on the recombinational capabilities. Inactivation action spectra based on photon fluence showed that the effectiveness of the radiation increased as the wavelengths became longer. Abrupt changes in the effectiveness occurred around the wavelengths corresponding to the absorption edges of K-shell electrons of phosphorus and calcium. In both cases, the sensitivity was the highest at the wavelengths of the resonance absorption peak, the next highest at those of the higher energy, and the lowest at the lower energy. Mass energy absorption coefficients of spores were obtained from the transmission of a flake made of spores. They were used to derive inactivation action spectra based on absorbed doses. In these spectra, basal levels of the sensitivity seemed constant, and enhancements of the sensitivity were observed consistent with the absorption by calcium and phosphorus. Thus calcium and phosphorus atoms were the predominant targets for the absorption events leading to the inactivation of spores in the wavelength range examined.

Bacillus subtilis↗
PubMed1991

Biological effects of Auger processes of bromine on yeast cells induced by monochromatic synchrotron X-rays.

The biological effects of inner-shell ionization in bromine atoms incorporated into DNA in the form of bromodeoxyuridine monophosphate (BrdUMP), induced by monochromatized synchrotron X-rays, were studied using a deoxythymidine monophosphate (dTMP)-permeable mutant of yeast, Saccharomyces cerevisiae. The BrdUMP-incorporated yeast cells were irradiated with monochromatic X-rays of 13.51 or 13.45 keV, between which the bromine K-absorption edge (13.47 keV) is located. The cells were 1.07 times more sensitive to irradiation by 13.51 keV X-rays than at 13.45 keV, while dTMP-incorporated cells did not show any difference in sensitivity. In the presence of a radioprotector during irradiation, BrdUMP-incorporated cells showed a larger enhancement (1.20). These enhancements observed in the bromine-incorporated cells cannot be explained only by an increase of the absorbed dose due to a substitution of CH3 group of thymine by bromine. It may be concluded that a major part of the enhancement was caused by inner-shell photoionization, followed by an Auger cascade of the bromine in the DNA. The quantum yield of lethality caused by the photoabsorption of bromine K-shell is not affected by the presence of cysteamine, suggesting the biological enhancement by the Auger processes may not be influenced by chemical protection.

Bromodeoxyuridine↗