Heavy-duty diesel-exhaust particles were collected, extracted and fractionated into diethyl ether-soluble neutral, acidic and basic fractions. The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA100, TA98, TA98NR and TA98/1,8-DNP6 in the presence and absence of a 9000 X g post-mitochondrial supernatant from Aroclor-induced rat liver (S9 mix). The neutral and acidic fractions showed high mutagenicity with TA98 in the absence of S9 mix, the acidic fraction having the highest specific activity. In the absence of S9 mix, the mutagenicity of crude, neutral and acidic fractions was greater in TA98 than in TA98NR and TA98/1,8-DNP6. Chemically-synthesized nitroacetoxypyrenes and nitrohydroxypyrenes were fractionated into the neutral and acidic fractions, respectively. These nitroarenes were purified by high-performance liquid chromatography and their mutagenicity was measured with the 4 strains. With TA98 in the absence of S9 mix, 1-nitro-3-acetoxypyrene, 1-nitro-6/8-acetoxypyrene, 1-nitro-3-hydroxypyrene, 1-nitro-6/8-hydroxypyrene induced 16 700, 336, 992, 94 His+ revertants per plate per nmole, respectively. In the absence of S9 mix, the level of mutagenicity of these nitroarenes was highest in TA98, lowest in TA98/1,8-DNP6 and intermediate in TA98NR. The neutral and acidic fractions of diesel-exhaust particles were analyzed by gas chromatography-mass spectrometry and gas chromatography-mass fragmentography. The neutral fraction was found to contain nitroacetoxypyrenes, 1-nitropyrene, 1,6-dinitropyrene, while nitrohydroxypyrenes were detected in the acidic fraction. The amounts of 1-nitro-3-acetoxypyrene, 1-nitropyrene, 1,6-dinitropyrene and 1-nitro-3-hydroxypyrene were 6.3, 62, 0.81, and 70 ng per mg of crude extract, and accounted for 12, 3.6, 8.0, and 9.0%, respectively, of mutagenicity of the crude extract in TA98 in the absence of S9 mix.

Animals↗

PubMedDate not supplied

Orofacial pain increases mRNA level for galanin in the trigeminal nucleus caudalis of the rat.

The changes of preprogalanin mRNA levels in the superficial dorsal horn neurons (laminae I and II) of the trigeminal nucleus caudalis in response to orofacial pain induced by the injection of 5% formalin into the lips of rats was investigated and compared to those of preproenkephalin A mRNA and preprodynorphin mRNA in the same region by means of in situ hybridization histochemistry. Rapid and marked increases of preprogalanin and preprodynorphin mRNA were observed on the side of the injection, but the increase of preproenkephalin A mRNA level was less pronounced than that of the other two mRNAs, indicating that these peptides have different roles in the dorsal horn analgesic mechanism and that galanin, in addition to opioid peptides, may have a highly specific role in this mechanism.

Animals↗

PubMedDate not supplied

Serial CT scans in subacute sclerosing panencephalitis.

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Brain↗

PubMedDate not supplied

Endoscopic management of esophageal meat impaction using a splay-mouth forceps.

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Aged↗

PubMedDate not supplied

Intraoperative identification of regenerated chorda tympani nerve and its relationship to recovered taste function.

This study demonstrated a simple method of repairing the severed chorda tympani nerve and a method of intraoperative identification of regenerated nerves, and evaluated taste function of regenerated nerves. Seven patients who underwent staged tympanoplasty and whose chorda tympani nerve was severed during primary surgery were evaluated. When the chorda tympani nerve was severed during primary surgery, proximal and distal stumps were anastomosed or approximated almost in the original position and fixed with fibrin glue on the temporal muscle fascia used to reconstruct the eardrum by the underlay method. During primary surgery, end-to-end anastomosis was possible in 3 patients but nerve gap defects remained in the other 4 patients. In all 7 patients, regenerated nerves were identified during secondary surgery not in the tympanic cavity but in the submucosal layer of the previously reconstructed eardrum. In all patients, complete or incomplete recovery of taste perception was observed by both the filter paper disk method and electrogustometry, suggesting that the regenerated nerves had actual taste function. From these results, it was concluded that the severed chorda tympani nerve could regenerate in the reconstructed eardrum even if nerve gap defects remained between the proximal and distal cut ends, when repair or approximation of the nerve was properly completed.

Adolescent↗

PubMedDate not supplied

Effect of dextran on gentamicin-induced ototoxicity.

The effect of low-molecular-weight dextran (DX) on gentamicin (GM)-induced ototoxicity was examined in guinea pigs. GM (100 mg/kg) was administered intramuscularly for 10, 12 and 14 days with or without DX. Cochlear damage was evaluated by compound action potential thresholds and surface preparation after fixation with osmium tetroxide. The percentage of missing outer hair cells was significantly increased by combined administrations of GM with DX. However, there was no significant difference in blood urea nitrogen levels in guinea pigs with or without DX. When aminoglycoside antibiotics and DX are administered together, attention should be paid not only to nephrotoxicity but also to ototoxicity.

Acoustic Stimulation↗

PubMedDate not supplied

Ototoxicity of the new platinum anticancer agent TRK-710 in comparison with cisplatin.

The pharmacokinetics and ototoxicity of the new platinum analogue TRK-710 (3, 9, 15 mg/kg x 3 days) were compared with those of cisplatin (1, 3, 5 mg/kg x 3). The perilymphatic concentration of TRK-710 was one seventh of that of cisplatin even 1 h after the administration. The N1 threshold of the compound action potential was elevated dose-dependently in both groups with a similar degree of hearing impairment. Morphological observation using phase contrast microscopy and scanning electron microscopy revealed the damage of the outer hair cells to almost the same degree mainly in the basal and second turns. Despite its usefulness against cisplatin-resistant tumors and a lesser degree of nephrotoxicity and myelosuppression, TRK-710 should be clinically used with caution similar to cisplatin.

Action Potentials↗

PubMedDate not supplied

Pseudohypoparathyroidism with striopallidodentate calcification--a case report and review of the literature.

One case of calcification in the striopallidodentate system associated with pseudohypoparathyroidism type I is described. Striopallidodentate calcification accompanying a disturbance in calcium metabolism is, to our knowledge, extremely rare with only thirteen previously documented cases reported, of which only two cases accompany pseudohypoparathyroidism. Moreover, our case showed an elevated titer of antiparietal-cell antibody.

Adult↗