Involvement of mechano-sensitive Piezo1 channel in the differentiation of brown adipocytes

Brown adipocytes expend energy via heat production and are a potential target for the prevention of obesity and related metabolic disorders. Piezo1 is a Ca2+-permeable non-selective cation channel activated by mechanical stimuli. Piezo1 is reported to be involved in mechano-sensation in non-sensory tissues. However, the expression and roles of Piezo1 in brown adipocytes have not been well clarified. Here, we generated a brown adipocyte line derived from UCP1-mRFP1 transgenic mice and showed that Piezo1 is expressed in pre-adipocytes. Application of Yoda-1, a Piezo1 agonist, suppressed brown adipocyte differentiation, and this suppression was significantly attenuated by treatment with a Piezo1 antagonist and by Piezo1 knockdown. Furthermore, the suppression of brown adipocyte differentiation by Yoda-1 was abolished by co-treatment with a calcineurin inhibitor. Thus, these results suggest that activation of Piezo1 suppresses brown adipocyte differentiation via the calcineurin pathway.

Electrocochleogram after transection of vestibulo-cochlear nerve in a patient with a large acoustic neurinoma

This study reports pre- and post-operative compound action potentials (CAPs) that were recorded from a 27-year-old woman with an acoustic neurinoma. During surgery it was necessary to totally sever her vestibulo-cochlear nerve to excise a large tumor. A pure tone audiogram changed to the scale-out pattern immediately after operation. However, CAP, the waveform of which was broadened, has been recorded 3 years post-operatively with a threshold elevation of 10 dB over the pre-operative threshold. This phenomenon suggests that CAP may originate from the extreme periphery of the auditory nerve within the cochlea. The broadening of the CAP was assumed to result from enhancement of the negative summating potential included in the CAP. We studied the effect of preceding stimulus on CAP using paired click stimuli pre- and post-operatively. A reduction of CAP amplitude in response to the second click of paired clicks was markedly suppressed in the inter-click interval between 3 and 80 ms post-operatively. We speculate that depletion of adaptation induced the abnormal CAP recovery described above and that the lateral efferent nerve system was involved in abnormal CAP adaptation with transection of the vestibulo-cochlear nerve in this case.

Successful conservative treatment of endometrial carcinoma permitting subsequent pregnancy: report of two cases

Two women with endometrial carcinoma who wished to preserve their childbearing ability received conservative treatment by medroxyprogesterone acetate (MPA, 600 mg/day for 22 weeks and 29 weeks, respectively). Following regression of endometrial lesions, their infertility was treated by inducing ovulation. Intact pregnancy was diagnosed 13 months and 11 months after completion of the MPA treatment, respectively. One patient had a twin pregnancy and delivered two infants at 35 weeks of gestational age. The other patient delivered a full-term baby. They had no evidence of recurrence 60 months and 31 months after the conservative treatment, respectively. We believe this conservative treatment with progestin may be safely performed for young patients with endometrial cancer who wish to preserve their fertility.

Cochlear function of guinea pigs with experimental chronic renal failure

This study aimed to evaluate electrophysiologically the cochlear function of guinea pigs that underwent a five-sixths nephrectomy and, additionally, to explore the synergistic action between chronic renal failure (CRF) and noise. Cochlear potentials were recorded at 1, 2, and 3 months postoperatively. Slight changes in compound action potential and cochlear microphonics were seen at 1 month postoperative, while moderate and profound changes were seen at 2 and 3 months. Endocochlear potential showed no significant reduction. The results indicate that CRF may be an etiologic factor for cochlear dysfunction and that the hair cells seem likely to be a main site of the lesion. One-month-postoperative animals were exposed to a broadband noise. In contrast to control animals, the test animals demonstrated no recovery from the decrease in compound action potential and cochlear microphonics that occurred immediately after noise exposure. This suggests a synergistic interaction between CRF and noise.

A silver-sulfadiazine-impregnated synthetic wound dressing composed of poly-L-leucine spongy matrix: an evaluation of clinical cases

The management of severe burns requires the suppression of bacterial growth, particularly when eschar and damaged tissue are present. For such cases, silver sulfadiazine (AgSD) cream has been traditionally applied. This antibacterial cream, however, cannot be used in conjunction with a temporary wound dressing that is needed to promote healing. The authors developed a synthetic wound dressing with drug delivery capability for clinical use by impregnating a poly-L-leucine spongy matrix with AgSD, which is released in a controlled, sustained fashion. In general, the dressing adhered firmly to the wound in the case of superficial second-degree burns, and during the healing process it separated spontaneously from the re-epithelialized surface. In the management of deep second-degree burns where eschar and damaged tissue were present, the dressing had to be changed at intervals of 3 to 5 days until it adhered firmly to the wound. Once the dressing had firmly attached to the wound, it was left in place until it separated spontaneously from the re-epithelialized surface. Dressing changes were fewer than with other treatments and the pain was effectively reduced. Cleansed wounds were effectively protected from bacterial contamination. Of 52 cases treated with this wound dressing, 93% (14/15) of superficial second-degree burns, 75% (3/4) of deep second-degree burns, 85% (6/7) of superficial and deep second-degree burns, and 75% (12/16) of split-thickness skin donor sites were evaluated as achieving good or excellent results.

[The effects of high-dose steroid therapy on sudden deafness]

The effect of high-dose steroid therapy on sudden deafness were investigated in 19 cases. A daily intravenous administration dose of hydrocortisone sodium succinate was tapered from 800 mg to 200 mg as follows; 800 mg 800 mg, 600 mg, 600 mg, 400 mg, 400 mg, 300 mg, and 200 mg. Another 19 cases, the control group, were treated with intravenous application of prednisolone, tapered from 50 mg to 10 mg in 10-mg steps and each dose applied for 3 days. There were no significant differences in the effect on hearing between the two groups as measured by three different analyses: criteria proposed by the Committee on Sudden Deafness of the Japan Health Ministry; magnitudes of improvement of mean thresholds at five frequencies from 250 Hz to 4 kHz in affected side; and the ratio of the magnitudes of improvement of mean thresholds in affected side to magnitudes of difference between the initial mean thresholds in affected side and those in contralateral side. These findings suggest that high-dose steroid therapy for sudden deafness is not so effective as it is for idiopathic facial palsy. This may be due to the difference in the mechanisms of development between the two conditions. No critical side effects were observed in our study, which would argue for the safety of our method of high-dose steroid therapy for routine clinical use. It might be advisable to conduct additional clinical studies to determine the effect of high-dose steroid therapy for sudden deafness, because our study was conducted on a small number of patients and was not double-blind or randomized.

Salicylate and quinine selectively increase spontaneous firing rates in secondary auditory cortex

This study presents firing rates for simultaneously recorded spontaneous and stimulus driven multi-unit activity in primary auditory cortex (AI), anterior auditory field (AAF) and secondary auditory cortex (AII) in cats before and after application of salicylate or quinine. From 21 cats, in three cortical areas simultaneously, a total of 1533 multi-unit files were obtained. The data suggest (1) that both salicylate and quinine significantly increase spontaneous firing rates in AII, whereas in AI and AAF both quinine and salicylate reduced the spontaneous rate; (2) the effect of both drugs was to increase spontaneous rates for recording sites with high characteristic frequency (CF) and a tendency to decrease them for low CF sites; (3) the mean stimulus driven firing rates were not affected by either drug except for a decrease produced by quinine in AI; (4) changes in driven firing rate were positively correlated with changes in spontaneous firing rates. This suggests that tinnitus inducing agents selectively increase spontaneous firing rates in the extralemniscal pathway.

Salicylate and quinine affect the central nervous system

Spontaneous local field potential (LFP) spindle frequencies in cat primary auditory cortex (AI) were estimated from the LFP-trigger autocorrelogram before and after application of sodium salicylate and quinine sulfate. A significant decrease (from 8.7 Hz to 7.6 Hz) was observed. The best modulation frequencies for 251 single units recorded in AI response to periodic click train stimulation also decreased (from 10 Hz to 8.6 Hz) after application of these tinnitus-inducing drugs. The results strongly suggest a central effect of salicylates and quinine in addition to their peripheral ototoxic effects.

[Functional changes in the cochlea of guinea pigs in chronic renal failure--electrocochleography. Effect of noise exposure]

An animal model of chronic renal failure (CRF) was created by the 5/6 nephrectomy procedure in guinea pigs. Levels of serum Cr and BUN were abnormally elevated at 1,2 and 3 months after the procedure. ECoG (CAP, CM) was recorded through a silver ball electrode placed on the round window 1,2 and 3 months after surgery. EP was measured with a glass microelectrode from the scala media via the round window membrane. Only slight ECoG changes were seen 1 month after surgery. On the other hand, moderate or profound changes were observed 2 and 3 months after-surgery. No significant decrease in EP was found in the post-surgery animals which distinctly showed abnormal CAP, CM, although a limited number of animals were studied. The above results indicate that CRF is one of the etiological factors of cochlear dysfunction and the sensory hair cells appeared to be the site of the lesion. To study the interaction between noise exposure and CRF, 1 month post-surgery animals with only a little change in ECoG were exposed to a broad band noise. Changes in the ECoGs were followed up for 6 hours after the noise exposure. In contrast to the controls, animals with CRF did not recover from the reduced ECoG which occurred immediately after the noise exposure. This suggests synergistic interaction between noise and CRF.

Autonomous cortical rhythms affect temporal modulation transfer functions

A correlational study between the dominant frequencies in the spontaneous local field potential and the single unit's best modulation frequency (BMF) for periodic click train stimulation in the primary auditory cortex of the cat is presented. Data were obtained from 251 single units recording in 29 cats. The correlation between spindle frequency (mean 8.2 Hz) and BMF (mean 9.3 Hz) was significant (r2 = 0.58, p < 0.0001). The limiting click-following rate was negatively correlated with the strength of the spindle rhythm: the longer the oscillation the lower the limiting rate. This suggests that the click-following responses of the primary auditory cortex depends as much on ongoing autonomous activity as it does on stimulus-induced activity.

Yearly variation of spontaneous somatic mutation frequency in the stamen hairs of Tradescantia clone KU 9 grown outdoors, which showed a significant increase after the Chernobyl accident

Scoring of spontaneous somatic pink mutation frequency in the stamen hairs of Tradescantia clone KU 9, a heterozygote for flower color (blue/pink; the blue color being dominant), was carried out for 11 years on plants grown outdoors, during the period of May 11-31 (for 3 weeks) in every year from 1982 to 1992. Weekly and yearly variations of the spontaneous mutation frequency were observed, and such variations could mostly be correlated to the difference in temperature. That is, the mutation frequency was generally higher in the weeks and years when the temperature was relatively low, showing the strongest negative correlation with the average minimum temperature. The variations were also correlated to the diurnal temperature difference, the mutation frequency being higher with larger diurnal temperature difference in general. However, the mutation frequency observed in 1986 was exceptionally higher than that expected from the temperature for this year, and was very significantly higher than for other years. The scoring of mutation frequency was thus continued in 1986 for an additional 4 weeks (June 1-28), and it was confirmed that such higher mutation frequencies lasted for 6 weeks in total. The exceptionally high mutation frequency seemed to be related to the radioactive fallout which occurred in early to mid May of 1986, even in Japan, after the serious nuclear reactor accident at Chernobyl, and also to the biological concentrations of radioactive nuclides which subsequently occurred, although it was difficult to conclude this definitely. The mutation frequency in 1987 was second highest, and was also significantly higher than the lowest mutation frequency observed in 1990.

Effects of administration of high dose hydrocortisone on Bell's palsy

As an improved maintenance therapy for Bell's palsy, Stennert recently introduced large-dose steroid administration in the early stage of the disease with i.v. infusion of low-molecular dextran. The steroid administration aims at improving the microcirculation. This therapy achieved a 96% complete healing rate. However, because of side-effects such as hepatic and renal disorders or gastric ulcer, this therapy has not been widely used. In the present study, we investigated an improved treatment method based on Stennert's method. It has a much lower incidence of side effects, and can be used in routine clinical practice. The medicines employed in our therapy were hydrocortisone sodium succinate (Solu-cortef), hydroxymethylated starch (Hespander) and D-mannitol (Manitol). Subjects were 53 Bell's palsy patients for whom treatment could be started within 2 weeks from the onset of the disease. Curative rate in the patients who received large-dose administration of Solu-cortef was 96.2% in the 24th week, and the therapy was considered to be applicable in routine clinical practice for Bell's palsy.

A cultured skin substitute composed of fibroblasts and keratinocytes with a collagen matrix: preliminary results of clinical trials

The cultured skin substitute was created through successive cultivation of fibroblasts and keratinocytes that were combined within a collagen matrix. This collagen matrix was composed of a collagen spongy sheet and a collagen gel. The collagen spongy sheet was designed to produce a honeycomb structure having many holes in which all holes through the sheet were filled with collagen gel. This specific structure thereby allows for the nourishment of the cultured keratinocytes on the surface of the matrix when placed on the graft bed. In this study, autologous cultured skin substitute was applied to a 51-year-old man who had sustained a burn injury. Three sheets of the cultured skin substitute (6 x 9.5 cm) were grafted onto the full-thickness excised wound in the right anterior chest wall. One week after grafting most of the matrix disappeared and stratified keratinocytes were seen to have firmly attached to the underlying tissue. Five weeks after grafting a cornified epidermal layer was seen. Ten months after grafting a mature epidermis and a well-differentiated papillary and reticular dermis replacement were observed. The physical properties and color of this grafted area resemble those of normal skin. In the second test case, autologous cultured skin substitute was applied to a 30-year-old man with a scar remaining after tattoo removal. Eight sheets of the cultured skin substitute (10 x 18 cm) were applied on an excised wound (thickness, 0.02-0.025 in.) of both the fore- and upper arms. The histological appearance of a biopsied skin specimen from the grafted area at 3 months after grafting showed a mature epidermis and a well-differentiated reticular dermis replacement. The regenerated skin at 14 months after grafting showed an excellent result.