Acupuncture Points ; Acupuncture Therapy ; Adolescent ; Alopecia ; physiopathology ; therapy ; Female ; Hair ; growth & development ; Humans

OBJECTIVE: Research of the hair damage due to perming, combing and stretching can be of important value for forensic hair individual identification. METHODS: The normal human hairs were treated with perming combing and stretching, and the keratins of the damage hair were analysed by using SDS-PAGGE and laser densimeter. RESULTS: Perming, combing and stretching brought about hair damage; The keratins of the damage hair were obviously reduced at the rang of molecular weight of 67,000-43,000 dalton. CONCLUSION The loss of the damage hair keratins were increased with the degree of the hair damage.
Adult ; Female ; Forensic Medicine ; Hair/physiopathology* ; Hot Temperature/adverse effects* ; Humans ; Keratins/metabolism*

The present study was to explore the functional and morphological changes in cochleas of guinea pig models of early endolymphatic hydrops. Thirty albino guinea pigs were randomly divided into three groups: control, 4-week model and 8-week model groups. For each group, n = 10. Model groups were operated on the right ears to result in endolymphatic hydrops with the method of slight destruction of endolymphatic sac and duct from extradural posterior cranial fossa approach, and the animals in control group were sham operated. Electrocochleogram recorded by trans-tympanic approach and auditory brainstem response (ABR) were tested in preoperative model groups, control group, 4-week model group and 8-week model group to assess the hearing changes. Histologic morphometry was used to quantify hydrops by testing scala media area (SMA) ratio. Scanning electron microscope was used to assess the changes of cochlea hair cells. The results showed that the summating potential/compound action potential (SP/AP) ratio of electrocochleogram in 4-week model group (0.33 ± 0.14) and 8-week model group (0.43 ± 0.14) increased significantly, compared with that in control group (0.07 ± 0.06). The maximum SMA ratio in 4-week model group (2.64 ± 0.10) and 8-week model group (3.54 ± 0.13) increased significantly, compared with that in control group (1.06 ± 0.08). The results of maximum SMA ratio correlated with SP/AP ratio of electrocochleogram (r = 0.86). The results of hearing threshold of ABR revealed that the operated ears of model groups were higher than the preoperative results at frequencies of 2 kHz and 4 kHz. And the damage of cochlea hair cells in operated ears occurred in apical and subapical turns. These results suggest the increased SP/AP ratio of electrocochleogram can indicate early endolymphatic hydrops. There is low-tone hearing loss in guinea pig models of early endolymphatic hydrops, and it may be associated with the abnormalities of the stereocilia among the outer hair cells in operated ears which occurs in apical and subapical turns.
Animals ; Cochlea ; pathology ; physiopathology ; Endolymphatic Hydrops ; complications ; physiopathology ; Guinea Pigs ; Hair Cells, Auditory, Outer ; pathology ; Hearing Loss, Sensorineural ; etiology ; pathology ; physiopathology ; Male

OBJECTIVETo investigate the feasibility of adipogenesis from human hair keratin (HHK) material, so as to provide a new method for fat defect and depression deformity.

METHODS3 Tibet mini-pigs were used. 8 fat defects (1.5 cm in diameter) were made bilaterally on the back. The ball-shaped HHK material was implanted to repair the defects at one side. The defects at contralateral side were as controls. The absorption of the HHK material and adipogenesis were studied histologically.

RESULTS2 weeks after implantation, connective tissue and capillary grew into the porous HHK material. 4 weeks after implantation, HHK material was almost totally absorbed, leaving some material debris and foreign body granuloma. Around them, there were clusters of adipocyte. 6 weeks after implantation, the HHK material was totally degraded and the granuloma was disappeared, and then de novo adipose tissue was observed. Its volume was close to the volume of peripheral HHK material that was planted originally. 10 weeks later, the new-formed fat tissue had less fibres and was very similar to the normal fat.

CONCLUSIONSNew adipose tissue can be formed after HKK material implantation. It can also be remodeled to be similar to normal fat.

Absorbable Implants ; Adipose Tissue ; injuries ; physiopathology ; Animals ; Disease Models, Animal ; Humans ; Keratins, Hair-Specific ; pharmacokinetics ; Swine ; Swine, Miniature

BACKGROUNDOur previous studies have shown that both apoptosis and necrosis are involved in hair cell (HC) pathogenesis in aging cochleae. To better understand the biological mechanisms responsible for the regulation of HC death, we examined the activity of succinate dehydrogenase (SDH), a mitochondrial bioenergetic enzyme, in the HCs of aging cochleae.

METHODSThe auditory brainstem response thresholds elicited by tone bursts at 4, 10 and 20 kHz were measured in both young (2-3 months) and aging (22-23 months) Wistar rats. SDH activity was evaluated with a colorimetric assay using nitroblue tetrazolium monosodium salt. The SDH-labeled organs of Corti were double stained with propidium iodide, a DNA intercalating fluorescent probe for illustration of HC nuclei. All the specimens were examined with fluorescence microscopy and confocal microscopy.

RESULTSAging rats exhibited a significant elevation of ABR thresholds with threshold shifts being 34 dB at 20 kHz, 28 dB at 10 kHz, and 25 dB at 4 kHz. Consistent with the reduction in the cochlear function, aging cochleae exhibited the reduction of SDH staining intensity in the apical and the basal ends of the cochleae, where a large number of apoptotic, necrotic, and missing HCs were evident. The reduction in SDH staining appeared in a cell-death-mode dependent fashion. Specifically, SDH labeling remained in apoptotic HCs. In contrast, SDH staining was markedly reduced or absent in necrotic HCs.

CONCLUSIONSIn the aging cochlea, SDH activity is preserved in HCs undergoing apoptosis, but is substantially reduced in necrosis. These results suggest that mitochondrial energetic function is involved in the regulation of cell death pathways in the pathogenesis of aging cochleae.

Aging ; metabolism ; Animals ; Apoptosis ; physiology ; Cochlea ; cytology ; enzymology ; Female ; Hair Cells, Auditory ; enzymology ; Male ; Necrosis ; physiopathology ; Rats ; Rats, Wistar ; Succinate Dehydrogenase ; genetics ; metabolism

OBJECTIVETo explore the protective effects of earplug and barrel on auditory organs of guinea pigs exposed to experimental blast underpressure (BUP).

METHODSThe hearing thresholds of the guinea pigs were assessed with auditory brainstem responses (ABR). The traumatic levels of tympanic membrane and ossicular chain were observed under stereo-microscope. The rate of outer hair cells (OHCs) loss was analyzed using a light microscope. The changes of guinea pigs protected with barrel and earplug were compared with those of the control group without any protection.

RESULTSAn important ABR threshold shift of the guinea pigs without any protection was detected from 8h to 14d after being exposed to BUP with a peak ranging from -64.5 kPa to -69.3 kPa ( P<0.01). The rate of perforation of tympanic membrane reached 87.5% and that of total OHCs loss was 19.46% +/- 5.38% at 14d after exposure. The guinea pigs protected with barrel and earplug had lower ABR threshold and total OHCs loss rate compared with the animals without any protection (P<0.01). All of the tympanic membrane and ossicular chain of the protected animals maintained their integrities. Meanwhile, the guinea pigs protected with the barrel had lower ABR threshold and total OHCs loss rate than those with earplug (P<0.01).

CONCLUSIONSThe earplug and barrel have protective effects against BUP-induced trauma on auditory organs of the guinea pigs and the protective effects of barrel are better than those of earplug.

Animals ; Auditory Threshold ; Blast Injuries ; prevention & control ; Ear Protective Devices ; Guinea Pigs ; Hair Cells, Auditory, Outer ; metabolism ; Pressure ; Tympanic Membrane ; injuries ; Tympanic Membrane Perforation ; etiology ; physiopathology ; prevention & control

OBJECTIVETo evaluate the effect of human hair keratin (HHK) in peripheral nerve repair and explore the mechanism of sciatic nerve regeneration.

METHODSRat models of sciatic nerve damage was established by creating a 10-mm gap in the sciatic nerve, which was bridged with a HHK implant. Histological examinations of the nerve tissues were performed at different time points after the surgery.

RESULTSDuring the period from 2 days to 2 weeks following HHK implantation, Schwann cells were found to undergo dedifferentiation and proliferate along the HHK implant. Three weeks after HHK implantation, numerous macrophages and megakaryocytes occurred around the HHK, and a large quantity of regenerated Schwann cells aligned in orderly fashion was seen between the fine filaments of partially degraded HHK, where axons and capillaries were also observed. Six weeks later, massive nerve fibers and capillaries developed around the HHK, and at 9 weeks, the HHK implant was substantially degraded and numerous regenerated nerve fibers occurred characterized by obvious epineurium and perineurium. Till 12 weeks after HHK implantation, HHK was almost completely degraded and replaced by the newly regenerated nerve fibers that had grown across the nerve defect.

CONCLUSIONSHHK is an ideal material for nerve injury repair. Apocytosis plays a key role in the differentiation process of highly differentiated Schwann cells into immature Schwann cells following nerve injury. As a protective mechanism, the axons undergo enclosure and dissociation following injuries, and the intact axons give rise to growth cones that extend fibers of growing buds to competitively bind the one or more Schwann cells, but only one such but finally develops into a complete axon. The nerve fiber barrier membrane is derived from the capillary menchymal stem cells and the outmost vascular barrier membrane. The regeneration of the Schwann cells, axons and the nerve membrane is the result of self-organization through a well synchronized and coordinated mechanism.

Animals ; Female ; Hair ; chemistry ; Humans ; Keratins ; administration & dosage ; pharmacology ; Male ; Nerve Regeneration ; drug effects ; physiology ; Prostheses and Implants ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; physiopathology

Although the basic principles for the function of peripheral auditory system have been known for many years, the molecular mechanisms which affect deafness are not clear. In recent years, the study of hereditary deafness associated mouse models has revealed the molecular basis which is related with the formation and function of the hair bundle and the mechanosensory organelle of hair cell. This review focused on the role of protein network, which is formed by the proteins encoded by the Usher syndrome type 1 genes, in hair-bundle development and mechanotransducer channel gating. And the review also showed how the stereocilia rootlets contribute to the hair bundle's mechanical properties and how the hair bundle produces suppressive masking. Finally, the review revealed multiple roles of the tectorial membrane and extracellular matrix in the hair bundles stimulating in the cochlea.
Animals ; Cochlea ; physiopathology ; Disease Models, Animal ; Extracellular Matrix ; physiology ; Hair Cells, Auditory ; pathology ; Hearing Loss, Sensorineural ; genetics ; Humans ; Mechanotransduction, Cellular ; Mice ; Usher Syndromes ; genetics

This study was designed to disclose the specific changes of distortion product otoacoustic emission (DPOAE), including DP-gram and I/O-gram in guinea pigs treated with GM for 10 and 17 days. Forty guinea pigs were divided into four groups:group I (treated with GM for 10 days), group II (treated with normal saline for 10 days), group III (treated with GM for 17 days), group IV (treated with normal saline for 17 days). DPOAE including DP-gram and DP-I/O was recorded by use of CELESTA 503 Cochlear Emission Analysis and the out hair cell loss was numerated. (1) The amplitude in group I showed significant reduction at frequencies of 4, 6, 8 kHz. There were significant differences, compared to group II (t=2.52, 1.92, 2.10, P<0.05). The amplitude in group III also decreased at frequencies of 3, 4, 6, 8 kHz. There were also significant differences compared to group IV (t=3.27, 2.81, 2.92, 3.13, P<0.01). The amplitude of DP-I/O in group I and group III at different frequencies and stimulus levels showed reduction. (2) At the level L1 <60 dB SPL, the stimulus levels to elicit a 0 dB response in group I and group III were higher than those in corresponding control groups, respectively. (3) The mean of threshold shift was 5.0+/-3.8 dB in group I and 25.0+/-6 dB in group III at 8 kHz frequency. (4) The out hair cell loss was 22.16% in group I and 48.36% in group III, both showed significant difference as compared to controls, respectively (P<0.01). The employment of DPOAE can be a useful tool in monitoring ototoxicity of GM for its sensitivity and specificity in guinea pigs treated with GM. The changes in DPOAE were consistent with those in histology.
Acoustic Stimulation ; methods ; Animals ; Cochlea ; drug effects ; physiopathology ; Female ; Gentamicins ; administration & dosage ; adverse effects ; Guinea Pigs ; Hair Cells, Auditory, Outer ; drug effects ; pathology ; Male ; Otoacoustic Emissions, Spontaneous ; physiology ; Perceptual Distortion ; drug effects ; physiology ; Random Allocation

INTRODUCTIONSensori-neural hearing loss (SNHL) is a frequent complication of conventional radiotherapy for head and neck tumours, especially nasopharyngeal carcinoma. To manage radiation-induced ototoxicity appropriately, an understanding of the cellular and molecular basis of this complication is necessary.

MATERIALS AND METHODSA medline search of relevant literature was done, focusing on the radiation-induced cellular and molecular processes that lead to hair cell death in the cochlea.

RESULTSRadiation-induced SNHL occurs in the cochlea, with the retro-cochlear pathways remaining functionally intact. By simulating radiotherapy regimes used clinically, radiation-induced cochlear cell degeneration in the absence of damage to the supporting structures and blood vessels has been demonstrated in animals. This could be due to apoptotic cochlear cell death, which has been shown to be associated with p53 upregulation and intra-cellular reactive oxygen species (ROS) generation. Oxidative stress may initiate the upstream processes that lead to apoptosis and other cell death mechanisms.

CONCLUSIONSA model of radiation-induced SNHL based on a dose and ROS-dependent cochlear cell apoptosis, is proposed. This model supports the feasibility of cochlear implantation, should one be clinically indicated. It can explain clinical observations such as radiation-induced SNHL being dose-dependent and affects the high frequencies more than the lower frequencies. It also opens up the possibility of preventive strategies targeted at different stages of the apoptotic process. Antioxidants look promising as effective agents to prevent radiation-induced ototoxicity; they target upstream processes leading to different cell death mechanisms that may co-exist in the population of damaged cells.

Animals ; Cell Death ; Cell Line ; Cochlea ; radiation effects ; Genes, p53 ; Hair Cells, Auditory ; radiation effects ; Hearing Loss, Sensorineural ; etiology ; genetics ; physiopathology ; Humans ; Mice ; Radiation Injuries ; complications ; Reactive Oxygen Species ; metabolism