Subchronic Inhalation Toxicity Study of n-pentane in Rats

OBJECTIVES: This study was conducted in order to obtain information concerning the health hazards that may result from a 13 week inhalation exposure of n-pentane in Sprague-Dawley rats. METHODS: This study was conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guidelines for the testing of chemicals No. 413 'Subchronic inhalation toxicity: 90-day study (as revised in 2009)'. The rats were divided into 4 groups (10 male and 10 female rats in each group), and were exposed to 0, 340, 1,530, and 6,885 ppm n-pentane in each exposure chamber for 6 hour/day, 5 days/week, for 13 weeks. All of the rats were sacrificed at the end of the treatment period. During the test period, clinical signs, mortality, body weights, food consumption, ophthalmoscopy, locomotion activity, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were assessed. RESULTS: During the period of testing, there were no treatment related effects on the clinical findings, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, relative organ weight, and histopathological findings. CONCLUSION: The no-observable-adverse-effect level (NOAEL) of n-pentane is evaluated as being more than 6,885 ppm (20.3 mg/L) in both male and female rats. n-pentane was not a classified specific target organ toxicity in the globally harmonized classification system (GHS).

Effect of Nano-sized Carbon Black Particles on Lung and Circulatory System by Inhalation Exposure in Rats

OBJECTIVES: We sought to establish a novel method to generate nano-sized carbon black particles (nano-CBPs) with an average size smaller than 100 nm for examining the inhalation exposure risks of experimental rats. We also tested the effect of nano-CBPs on the pulmonary and circulatory systems. METHODS: We used chemical vapor deposition (CVD) without the addition of any additives to generate nano-CBPs with a particle size (electrical mobility diameter) of less than 100nm to examine the effects of inhalation exposure. Nano-CBPs were applied to a nose-only inhalation chamber system for studying the inhalation toxicity in rats. The effect on the lungs and circulatory system was determined according to the degree of inflammation as quantified by bronchoalveolar lavage fluid (BALF). The functional alteration of the hemostatic and vasomotor activities was measured by plasma coagulation, platelet activity, contraction and relaxation of blood vessels. RESULTS: Nano-CBPs were generated in the range of 83.3-87.9 nm. Rats were exposed for 4 hour/day, 5 days/week for 4 weeks to 4.2 x 10(6), 6.2 x 10(5), and 1.3 x 10(5) particles/cm3. Exposure of nano-CBPs by inhalation resulted in minimal pulmonary inflammation and did not appear to damage the lung tissue. In addition, there was no significant effect on blood functions, such as plasma coagulation and platelet aggregation, or on vasomotor function. CONCLUSION: We successfully generated nano-CBPs in the range of 83.3-87.9 nm at a maximum concentration of 4.2 x 10(6) particles/cm3 in a nose-only inhalation chamber system. This reliable method can be useful to investigate the biological and toxicological effects of inhalation exposure to nano-CBPs on experimental rats.

The Effect of Low-dose Ketamine on the Incidence of Emergence Agitation in Preschool Children Receiving Sevoflurane Anesthesia: Comparison with Ketorolac / 대한마취과학회지

BACKGROUND: Emergence agitation is a common side effect of sevoflurane anesthesia in preschool children. Low-dose ketamine is defined as a bolus dose of less than 1 mg/kg when administered via the intravenous route, and produces potent analgesia without respiratory depression or other side effects. In this study, we examined the effect of low-dose ketamine on the incidence of emergence agitation in preschool children receiving sevoflurane anesthesia and compared this with the effect of ketorolac. METHODS: Sixty eight preschool children receiving sevoflurane anesthesia were randomized to receive either ketorolac 1 mg/kg or ketamine 0.2 mg/kg intravenously before the end of surgery. Emergence agitation was assessed using a 3-point scale (1 = asleep, calm, or mildly agitated but easily consolable; 2 = moderately agitated or restless but inconsolable; and 3 = hysterical, crying inconsolably, or thrashing) during transfer and at 10 minutes after arrival at our postanesthesia care unit. RESULTS: We observed that the incidences of emergence agitation were 30.0%, 45.0% in the ketamine group, and 60.7%, 78.6% in the ketorolac group (P < 0.05) during transfer and at 10 minutes after arrival at the postanesthesia care unit, respectively. No significant difference was observed between the two groups with respect to discharge time from the postanethesia care unit. CONCLUSIONS: Emergence agitation after sevoflurane anesthesia in preschool children was significantly reduced by low-dose ketamine as compared with ketorolac without delaying recovery.

Lumbar Sympathetic Ganglion Block with Alcohol for Plantar Hyperhidrosis / 대한통증학회지

BACKGROUND: Chemical lumbar sympathetic ganglion block could potentially be used to treat plantar hyperhidrosis; therefore, we analyzed the outcome of lumbar sympathetic ganglion block using alcohol for the treatment of plantar hyperhidrosis. METHODS: Between March 1992 and June 2003, 356 patients with plantar hyperhidrosis underwent lumbar sympathetic ganglion block using alcohol. All 356 patients were followed up for 2 years and the results evaluated. There were 185 and 171 male and female patients, respectively, with a mean age of 25.1 years, ranging from 15.3 to 56.5 years old. Lumbar sympathetic ganglion block using alcohol was performed with fluoroscopic guidance under local anesthesia. RESULTS: The recurrence rate after 2 years was 34%. Compensatory hyperhidrosis, ejaculation failure, lower back pain and genitofemoral neuritis developed as complications in 132, 4, 12 and 2 patients, respectively. Of the 356 patients, 65% were satisfied. CONCLUSIONS: Lumbar sympathetic ganglion block using alcohol is an effective and safe method for the treatment of plantar hyperhidrosis, but more information about the complications and relatively high recurrence rates should be provided to the patient.