Production of interferon-gamma by human peripheral T-cell subsets in response to mumps virus.
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Cell Separation↗
Biomedical subjects
N Maehara
Publications and source records attributed to N Maehara.
Effects on cochlear microphonics in guinea pigs induced by prolonged exposure to low-frequency sound.
The effects on CM induced by 46.5 h exposure to low-frequency sound of 0.125 kHz at 115 dB (SPL) and 100 dB (SPL), which frequency is considered to be in the vicinity of the lowest limit of audiofrequency for guinea pigs, were investigated by the sound pressure levels at which CM output voltages produced 50 microV (50 microV isopotential responses) at test frequencies of 0.06, 0.08, 0.12, 0.18, 0.25, 0.5, 1, 2, and 4 kHz, and by the intensity function measured from 65 to 120 dB (SPL) at test frequencies of 0.06, 0.08, 0.12, 0.18, 0.25, 0.5, 1, and 2 kHz. The results obtained were as follows. In 50 microV isopotential responses measured at about 30 min after the termination of sound exposure, the mean dB in the 115 dB-exposed group tended to elevate at all test frequencies of 0.06 kHz to 4 kHz as compared with those in the control group. Significant dB elevations were especially observed at 0.06, 0.12, 1, 2, and 4 kHz. In the 100 dB-exposed group, however, no significant dB elevations were observed at any test frequencies as compared with those in the control group. In the intensity function measured at about 40-60 min after the termination of sound exposure, the mean output voltages in the 115 dB-exposed group induced by test stimuli of 0.18 kHz-2 kHz at higher intensities showed significant depression in comparison with those in the control group (by over 110 dB at 0.18 and 0.25 kHz, and by over 90 dB at 1 and 2 kHz).(ABSTRACT TRUNCATED AT 250 WORDS)
Acoustic Stimulation↗
An experimental study of the effects of lead acetate on hearing. Cochlear microphonics and action potential of the guinea pig.
Guinea pigs were poisoned with repeated i.p. injections of 1% lead acetate. After 5 weeks, the animals were examined electrophysiologically by using cochlear microphonics (CM) and action potential (AP). The thresholds of maximum voltage of N1 in the AP of the animals injected with a total of 100 mg lead acetate were elevated about 15 dB and increased N1 latency was also observed. However, no significant changes in those of CM were found. The results suggest that lead acetate not only induces damage to the peripheral nerves, but also to the cranial nerves.
Action Potentials↗
Effects of trichloroethylene exposure on hearing. An investigation of cochlear microphonics and action potential of the guinea pig.
Four groups of guinea pigs with normal Preyer's reflex were exposed to trichloroethylene (TCE). Each group consisted of nine to 10 naive male albino Hartley guinea pigs of 9 weeks of age with a body weight of approximately 400 g. To test the suggestion that TCE causes damage to the cochlear system, a study was conducted involving four experiments. The results were as follows: No significant difference was observed between the intensity functions of the CM (4 kHz) and AP (7 kHz) potentials of the control groups and those of the TCE-exposed groups by analysis of variance. It was considered that there was no difference in the cochlear reaction to high frequency sound between guinea pig and man. It therefore might be suggested that acute exposure to TCE of a high concentration does not always induce dysfunction of the organ of Corti and the 8th nerve in man.
Action Potentials↗
Effect of acute stresses on Zn-thionein production in rat liver.
Male Wistar strain rats were exposed to acute stress from broad-band noise [100 dB (A) for 1 h] or cold (4 degrees C for 24 h). Following exposure to noise for 1 h, serum and adrenal gland showed about 1.8 times and 2.5 times the corticosterone levels of the control group, but this enhancement was not observed after exposure to cole. Both stresses increased Zn-thionein significantly in the liver. Furthermore, the two stresses increased the content of Zn in the 30,000 g supernatant fraction of the liver, though serum Zn concentration was not altered. It is believed that thionein is a regulatory protein with a specific function for Zn metabolism in organs. Although it is known that corticosterone affects Zn metabolism in man and animals, there is little investigation of the effect of environmental stresses on Zn metabolism. The present data suggest that Zn metabolism may be important in the investigation of the effects of repeated and long term exposure to environmental stresses involving noise and cold.
Acute Disease↗
Electrophysiological responses in guinea pig cochlea to low frequency sound stimuli: distortion of cochlear microphonic (CM) wave form.
The present experiment investigated whether or not auditory responses of the middle and/or inner ear in guinea pigs to low frequency sound stimuli [ 60 Hz-2 kHz at 90-120 dB(SPL) ] exhibited the harmonic distortion phenomenon resulting from cochlear microphonics (CM). Measurement of CM leading in turn I by the differential electrode recording method involved measurement of 50 microV isopotential responses, output voltages and CM wave form distortion at each constant sound pressure. The results obtained were as follows: (1) On the 50 microV isopotential response curve and the output voltage curves, the changes at 60-90 Hz were different from those at higher frequencies. (2) At stimuli of 90 or 100 dB(SPL), CM wave form distortion appeared frequently at frequencies below 120 Hz, but were less pronounced above approximately 200 Hz. (3) When raised to 110 and 120 dB(SPL), almost all CM wave forms were distorted at all test frequencies between 60 and 500 Hz. (4) The patterns of CM wave form distortion at frequencies below approximately 120 Hz showed peak clipping and triangular wave distortions, while those at frequencies above approximately 200 Hz showed little of these distortions.
Acoustic Stimulation↗
Effect of intermittent (traffic) noise on man--temporary threshold shift, and change in urinary 17-OHCS and saliva cortisol levels.
Eight healthy male college students were selected and eight noise exposure conditions were planned. The noise exposure time of all the experiments was 14 h. Measurement of the TTS growth at 4 kHz was investigated during these 14 h. Saliva collected every 3 h was also examined for cortisol throughout the 24-h period. The exposure noises used in this experiment were pink noise and pure tone of 3 kHz. The time patterns of trapezoidal noise were as follows. The rise and decay times were 1 s respectively and the peak level was 1 s for the (A I type), being 500 ms and 1.5 s respectively for the (A II type). Three measurements were made: 1. TTS. Under intermittent noise exposure at 80 dB(A), exposure of 20% of the on fraction induced significant TTS growth, but exposure of 13% of the on fraction did not induce TTS growth. Under exposure at 75 dB(A), exposure of 66% of the on fraction did not induce TTS growth. Under pure tone exposure of 3 kHz at 75 dB(A), exposures of 20% and 30% of the on fraction did not induce TTS growth. There was a significant difference between the TTS induced by a steady state of of 73 dB (A) (Leq of Exp. 2) and that of Exp 2. 2. Urinary 17-OHCS Level. During the noise exposure period (14h), there was a statistically significant difference between the urinary 17-OHCS level of the control condition and that of Exp. 3. In addition, there was no statistically significant difference among the urinary 17-OHCS levels of post-noise exposure. 3. Saliva Cortisol. With intermittent "pink noise" of 75 or 80 dB(A) (Exp. 2, 3, and 4), however, temporary elevation of the saliva cortisol level occurred only at the initial stage of exposure, and lasted for only one hour. Moreover, with steady state noise exposure, evanescent elevation occurred at the lower level of 71 dB(A).
17-Hydroxycorticosteroids↗
Enhanced production of interferon by ultraviolet irradiation and pretreatment with interferon in human diploid cells stimulated with polyinosinate-polycytidilate.
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Cell Line↗
Physiological responses induced by 555-min exposure to intermittent noise.
Normal medical college students were exposed to noise for 555 min, while the Temporary Threshold Shift (TTS) and changes in the circulatory system were measured. The exposure noise employed was the so-called pink noise of a trapezoidal form. There were two time patterns, A(I) with 1 s of rise-decay time and 1 s of peak level, and A(II) with 500 ms of rise-decay time and 3.5 s of peak level. Thirteen exposure conditions were examined. The noise exposure time of all experiments was 555 min. The following results were obtained. 1. TTS Growth. Significant TTs increases were obtained following exposure to intermittent noise of 85 dB(A), intermittent noise of 80 dB(A), and steady state noise of various intensities. The TTS growth observed with steady state noise at 80 dB(A) was significantly greater than that of intermittent noise exposure at 85 dB(A). Moreover, TTS growth observed with steady noise at 82 dB(A) was significantly greater than that with intermittent noise exposure of 85 dB(A). However, the levels of TTS growth observed with steady state noise of 75 dB(A) and steady state noise at 77 dB(A) were almost equal to those of 6 s trapezoidal noise at 80 dB(A) (the "on fraction" being 33%), and 8 s trapezoidal noise at 80 dB(d) (the "on fraction' being 50%). In the above-mentioned experiments, significant increases of TTS growth were observed with various cycle times of trapezoidal noise with peak levels of 85 dB(A) and 80 dB(A), and with four exposure noise conditions of steady state. Under exposure conditions of 75 dB(A), trapezoidal noise with a 6 s cycle time (the "on fraction" being 33%) did not show a significant increase in TTS growth. 2. Changes in the Circulatory System. There were no significant differences in systolic and diastolic pressure or pulse rate among the three exposure conditions. The findings on ECG were as follows. Under intermittent noise exposure, decrease in the height of the T wave was observed in all examinees with a depression of the ST segments also being observed in two cases. On exposure to steady state noise, however, slight decrease in the height of the T wave was induced in only two cases, and under control conditions in only one case.
Adult↗
Production of interferon in human diploid cells at different population doubling levels.
Interferon (IFN) yield after superinduction declined gradually by in vitro senescence of the cells, while it remained unchanged in IFN-pretreated cells. IFN yield after stimulation with Newcastle disease virus remained unchanged by in vitro senescence.
Cell Line↗
Induction of interferon by bacterial endotoxin.
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Animals↗
Effects of toluene exposure on blood pressure and its responsiveness to impulse noise in rats.
Effects of a single exposure to toluene at a concentration of 1000 for 4 h on rats' systolic blood pressure were investigated. 9 rats were used in each group (control and exposed groups). The basic blood pressure of the exposed group was significantly lower than that of the control group. The movement of systolic blood pressure due to impulse noise exposure was significantly smaller in the exposed group than in the control group. Toluene exposure at concentration of 1000 ppm for 4 h produced narcotic and inhibitory actions in the diencephalohypophysial and the adrenal gland system in rats.
Animals↗
Effects of toluene exposure on the rest-activity cycle of rats.
Rats were exposed to toluene at a concentration of 1000 ppm, 6 h/day, 6 times weekly, for 4 weeks. Functional disturbance of the circadian rhythm of spontaneous activity was found after repeated exposure to toluene, although single exposure under the same conditions did not influence the rhythm. The disturbance was characterized by a significant increase in distribution of activity in the "Light' (L) period, and a significant relationship was observed between the total number of days of exposure and the activity level in the L period. The toluene concentration in the blood immediately after the exposure was 6.8-7.2 microgram/ml after one and 18 days of exposure, respectively.
Animals↗
The effects of intermittent (trapezoidal) noise on man.
Eight healthy students were exposed to intermittent noise to evaluate the effects of traffic noise on man. The experimental noise exposure conditions were as follows: Exp. 1: Control. Exp. 2: Peak level, 80 dB(A); rise-decay time, 1 sec; duration, 3 sec; and duty cycle 8 sec (on fraction 25%). Exp. 3: Peak level, 75 dB (A); rise-decay time, 500 msec; duration, 4.5 sec; and duty cycle, 8 sec (on fraction 50%). In all experiments, the exposure time was 14 hr. Temporary threshold shift (TTS) growth was followed for 14 hr while saliva cortisol levels were measured for a 24-hr period. Although the coefficient of the regression line of TTS growth recorded in Exp. 1 or Exp. 3 was not statistically significant, the value in Exp. 2 was statistically significant. The circadian rhythm pattern of the saliva cortisol level (during a 24-hr period, mean of 8 examinees) was observed in the three experiments. Essentially, the early morning level of saliva cortisol was high, while the daytime level was relatively low.
Adult↗
Enhanced production of virus-inhibiting factor (interferon) in human diploid cells by ultraviolet irradiation and temperature shift-down after stimulation with Newcastle disease virus.
The production of the virus-inhibiting factor or interferon (IF) was highest in cells incubated at 37 C after inoculation with Newcastle disease (ND) virus and decreased as the incubation temperature was lowered. Shift-down of incubation temperature to 32 C or 34 C after incubation at 37 C for 4--7 hr enhanced IF production in cell cultures stimulated with ND virus, as compared with cultures incubated continuously at 37 C. Shift-down to 32 C after incubation at 37 C for 6 hr was optimal for this enhancement of IF yield. Enhanced IF production was also observed in cell cultures irradiated by ultraviolet light 4--7 hr after stimulation with ND virus.
Cell Line↗
Cellular origin of interferon induced by bacterial lipopolysaccharide.
Bacterial lipopolysaccharide (LPS) induces interferons with different properties in mouse macrophages and B lymphocytes. Macrophage interferon is labile at 56 degrees C and is neutralized by anti-mouse fibroblast interferon at a dilution of 1:6,142. B cell interferon is more heat stable and is neutralized by the same antiserum only at a dilution of 1:276. Serum obtained early (1 h) after an intravenous injection of 100 mug of LPS resembled macrophage interferon, whereas serum obtained at later times resembled more and more B cell interferon. The diverse cellular origin of LPS-induced interferon may explain the broad hyporesponsiveness produced by LPS in animals.
Animals↗
Differences in mouse interferons according to cell source and mode of induction.
Mouse interferon induced by ultraviolet-irradiated Newcastle disease virus or polyriboinosinic-polyribocytidylic acid in T lymphocytes, B lymphocytes, macrophages, and primary mouse embryonic cell culture was studied. Irrespective of the inducer, interferons produced by T or B lymphocytes were relatively heat stable and of low antigenicity when reacted with antiserum against L-cell interferon (ALI), whereas interferons produced by macrophages and mouse embryo cells were heat labile and of high antigenicity against ALI. Mouse interferons induced by ultraviolet-irradiated Newcastle disease virus were separated into three components by chromatography on CH-Sepharose 4B. Interferons produced by T and B lymphocytes consisted primarily of component 1 (unbound fraction), whereas interferons produced by macrophages or mouse embryo cells consisted primarily of component 3 (eluted by 0.5 M NaCl). Component 1 was heat stable and of low antigenicity against ALI, properties characteristic of T- and B-cell interferon. Components 2 and 3 were heat labile and of high antigenicity against ALI, properties characteristic of macrophage and mouse embryo cell interferon. In contrast, interferon induced in mice sensitized with BCG differed from these interferons induced in B cells, T cells, macrophages, and fibroblasts in being extremely acid labile and nonreactive against ALI.
Animals↗
Cellular basis of interferon formation and hyporeactivity after exposure to bacterial lipopolysaccharide.
Endotoxin apparently induces interferon in only a few types of cell, yet it produces strong hyporesponsiveness to a large number of agents. After incubation for 24 hr with endotoxin in vitro, tissue cultures of thymus, spleen, mesenteric lymph nodes, and to a lesser extent, liver and lung produced interferon. Lymphoid tissues of bone marrow-derived (B-) cells (sacculus rotundus, appendix, and Peyer's patches) and kidney did not produce interferon. Adherent spleen cells produced more interferon than nonadherent cells. Purification of spleen cells on a bovine serum albumin gradient showed that light, DNA-synthesizing cells made interferon in response to endotoxin or polyriboinosinic-polyribocytidylic acid. Mouse spleen cells produced a "late" interferon 24-48 hr after exposure to endotoxin, which, in contrast to "early" interferon (produced at 0-24 hr) from spleen and other tissues, is stable at 56 C for 60 min. It is suggested that this late interferon represents a "B-cell" interferon. Hyporeactivity was produced in vitro by endotoxin only in tissues that make endotoxin-induced interferon, a fact consistent with the theory that the interferon-inducing mechanism must be initiated before hyporeactivity results. The fact that endotoxin has been found to act on a fairly large range of cells (i.e., macrophages, thymus-derived cells, and probably B-lymphocytes) explains its ability to produce broad hyporesponsiveness.
Animals↗