Low-level laser therapy alleviates mechanical and cold allodynia induced by oxaliplatin administration in rats.

PURPOSE: Cold and mechanical allodynia caused by oxaliplatin-induced acute peripheral neuropathy frequently occur after drug infusion. Low-level laser therapy (LLLT) has been used to improve pain symptoms associated with various conditions and may have potential as a therapy for oxaliplatin-induced allodynia. The purpose of the present study was to investigate the antiallodynic effect of LLLT in an oxaliplatin-treated animal model by assessing sensory behavioral responses, levels of nerve growth factor (NGF), and transient receptor potential M8 (TRPM8) in dorsal root ganglia (DRG) neurons, as well as substance P (SP) in the spinal dorsal horn. METHODS: Adult male Sprague-Dawley rats each received a total of four doses of oxaliplatin (4 mg/kg, i.p.), injected at 3-day intervals. Following oxaliplatin administration, LLLT (7.5 J/cm(2)) was applied for 12 consecutive days to the skin surface directly above sites where the sciatic nerve is distributed. Behavioral assessments were then performed, followed by immunoassays for NGF, TRPM8, and SP proteins. RESULTS: LLLT relieved both cold and mechanical allodynia induced by oxaliplatin in rats. Oxaliplatin-related increases in protein levels of NGF and TRPM8 in DRG and SP in the dorsal horn were also reduced after LLLT. CONCLUSION: The findings of this study support LLLT as a potential treatment for oxaliplatin-induced neuropathy. Moreover, our findings suggest that SP, TRPM8, and NGF proteins in the superficial dorsal horn and DRG may be involved in an antiallodynic effect for LLLT.

SGN nerve filaments develop synapses with IHCs earlier than with OHCs in C57BL/6 mouse inner ear.

OBJECTIVE: To explore the connections between hair cells and spiral ganglion neurons (SGNs) during the development of the C57BL/6 mouse inner ear. MATERIALS AND METHODS: The specimens of C57BL/6 mouse inner ear, from E15 (embryo day 15) to adult mouse, were collected; immunohistochemistry was employed to explore the frozen sections of specimens. RESULTS: The development of cochlea starts sequentially from the basal turn to the apex turn. Morphological development of SGNs occurs mainly from E16 to P12 (postnatal day 12). Hair cells appear from E18 to P12, and inner hair cells (IHCs) develop earlier than outer hair cells (OHCs). The connections between hair cells and SGNs begin to develop during E18-P1, morphologically resemble mature synapses during P8-P12, and completely mature in adult mice. CONCLUSIONS: The genesis of auditory ribbon synapse occurs from E18 to P1. Synchronized with the development of SGNs and hair cells, the functional filaments remain connected to hair cells, while the spare ones get disconnected from the surface of hair cells. Connections between SGN nerve filaments and IHCs occur earlier than those between SGN nerve filaments and OHCs.

Influences of surgical decompression on the dorsal horn after chronic constriction injury: changes in peptidergic and delta-opioid receptor (+) nerve terminals.

To understand plastic changes in the dorsal horn related to neuropathic pain, we developed a model of decompression in rats with chronic constriction injury (CCI) and investigated corresponding changes in the dorsal horn. At postoperative week 4 (POW 4) of CCI, rats were divided into a decompression group, in which ligatures were removed, and a CCI group, in which ligatures remained. Spinal cords were immunostained for substance P (SP), the delta-opioid receptor (DOR), and calcitonin gene-related peptide (CGRP). Areas of immunoreactive nerve terminals in the dorsal horn were quantified and expressed as the dorsal horn index (immunoreactive areas of the operated side compared with those of the contralateral side). At POW 4, dorsal horn indexes of all of these molecules were significantly reduced in both groups to similar degrees (0.36-0.43). At POW 8, neuropathic pain behaviors had completely disappeared in the decompression group with significant reversal of the dorsal horn indexes compared with the CCI group (0.81+/-0.02 vs. 0.58+/-0.09, P < 0.001 for SP and 0.75+/-0.04 vs. 0.55+/-0.03, P < 0.001 for DOR). In the CCI group, neuropathic pain behaviors became normalized at POW 12 with corresponding changes in dorsal horn indexes for both SP and DOR similar to those of the decompression group. In contrast, changes in the dorsal horn indexes of CGRP were similar in both the CCI and decompression groups throughout the experimental period. These findings suggest that CCI and decompression cause different patterns in peptidergic and DOR (+) nerve terminals in the dorsal horn.

Improved treatment results for childhood acute myeloid leukemia in Taiwan.

To improve treatment results for children with de novo acute myeloid leukemia (AML), we introduced a novel protocol, Taiwan Pediatric Oncology Group-AML-97A, for AML other than acute promyelocytic leukemia (APL), for which modified conventional protocols were used. From January 1, 1997, to December 31, 2002, 141 children younger than 17 years old with de novo AML were enrolled. In total, 117 patients with non-APL AML were treated with induction therapy of idarubicin and cytarabine (Ara-C), postremission therapy with high-dose Ara-C - containing regimens for four monthly courses, and moderate-dose therapy with idarubicin and Ara-C for four monthly courses. The first 19 patients with APL were treated with all-trans retinoic acid, idarubicin and Ara-C, with the remaining five patients receiving all-trans retinoic acid and idarubicin, followed by maintenance therapy for 2 years. Stem cell transplantation was performed in 29 patients in first remission with a similar outcome as chemotherapy alone. The remission rate in the AML-97A study was 90%, the 5-year survival 51 +/- 5.3% (s.e.) and the 5-year event-free survival 50 +/- 4.8%; for APL, these were 100%, 86 +/- 7.0, and 75 +/- 9.8%. For the whole group, the 5-year survival was 57 +/- 4.7% and the 5-year event-free survival 54 +/- 4.4%. The AML-97A regimen was well tolerated.

Molecular cloning of the cDNAs for pituitary glycoprotein hormone alpha subunits of two species of duck and their gene regulation.

The cDNAs encoding pituitary glycoprotein hormone alpha subunits (PGHalphas) of two species of duck (Muscovy duck, Cairina moschata and Pekin duck, Anas platyrhynchos domesticus) were cloned and sequenced to better understand the phylogenic diversity and evolution of PGHalpha molecules in vertebrates. Oligonucleotide primers were designed and used for reverse transcription PCR (RT-PCR) amplification of PGHalpha cDNA fragments from total cellular RNA of pituitary glands. The remaining sequences were completed by rapid amplification of the cDNA ends. The nucleotide sequence of isolated PGHalpha cDNA of both ducks are identical, including 81 bp of 5' untranslated region (UTR), 360 bp of coding region, and 272 bp of 3'-UTR followed by a 13 bp poly(A)(+) tract. The total number of amino acids deduced from the cDNA of the duck PGHalpha is 120 with a signal peptide of 24 amino acids and a mature protein of 96 amino acids. PGHalphas of the ducks (order Anseriformes) share 96% homology of amino acid sequence in signal peptide, and 100% homology in mature proteins with chicken, quail and turkey (order Galliformes). Our data thus demonstrate identical inter-order homology of PGHalpha mature protein in birds. Ten cysteine residues, presumably forming five disulfide bonds within the alpha subunit, and four proline residues, presumably responsible for folding of the molecule, are conserved in the alpha subunit of ducks. Northern blot analysis revealed that PGHalpha mRNA is expressed only in the pituitary. In order to study factors regulating the gene expression of PGHalpha mRNA, duck pituitary fragments were incubated with GnRH, TRH, testosterone, or triiodothyronine (T(3)). GnRH and TRH increased, while testosterone and T(3) decreased, PGHalpha mRNA levels. This is the first report in birds of TRH up-regulation and down-regulation by testosterone and T(3) under in vitro conditions. The present study demonstrates both ducks have the same cDNA nucleotide and deduced amino acid sequences in the PGHalpha subunit, exhibiting identical inter-genus homology within the family of Anatidae. The findings from mRNA expression work suggest that hypothalamic GnRH and TRH up-regulate, while testosterone and T(3) down-regulate, PGHalpha gene expression in ducks.

Perturbation of platelet adhesion to endothelial cells by plasminogen activation in vitro.

To investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as epsilon-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.

Studies on heme binding in myoglobin, hemoglobin, and cytochrome c by ion spray mass spectrometry.

The ion spray mass spectra of three representative heme-containing proteins were studied, with an emphasis on results obtained under neutral (pH 7) aqueous conditions. The noncovalently bound heme in myoglobin and hemoglobin may be readily distinguished from the covalently bound heme prosthetic group attached to cytochrome c by using collisioninduced dissociation in the free-jet expansion region of the mass spectrometer as well as in the collision quadrupole with premass selection. The charge state of iron in the expelled heme from myoglobin and hemoglobin appears to be 3+ but 2f for heme expelled from cytochrome c.

Detection of noncovalent FKBP-FK506 and FKBP-Rapamycin complexes by capillary electrophoresis-mass spectrometry and capillary electrophoresis-tandem mass spectrometry.

The well known biospecific noncovalent receptor-ligand association complexes between the immunophilin FKBP and the immunosuppressive drugs FK506 and Rapamycin (RM) were investigated by on-line capillary electrophoresis-mass spectrometry (CE-MS) under selected ion monitoring (SIM) conditions and by CE-MS with tandem mass spectrometry (CE-MS/MS) under selected reaction monitoring (SRM) conditions. Solutions of hFKBP (33.3 µM) were dissolved in 50 mM ammonium acetate at pH 7.5. Samples that contained 100 µM of FK506 or RM also were prepared under the same solution conditions. By using these aqueous pH neutral conditions, samples were analyzed by SIM CE-MS and SRM CE-MS and the target complexes were separated by CE with mass spectrometer detection of the individual complexes between FKBP and FK506 [hFKBP + FK506 + 7HJ(7+) as well as FKBP and RM [hFKBP + RM + 7HJ(7+). In an experiment where a mixture of FK506 and RM was analyzed in the presence of FKBP, a nine-to-one ratio of ion current abundances between the RM and FK506 complexes was observed as reported in the literature from other studies. These results suggest that CE-MS and CE-MS/MS may be yet another analytical method for studying noncovalent interactions of biologically important macromolecules under physiological conditions.

Molecular cloning of cDNA encoding thyroid stimulating hormone beta subunit of bighead carp Aristichthys nobilis and regulation of its gene expression.

The complementary DNA (cDNA) encoding pituitary thyroid stimulating hormone beta subunit (TSH-beta) of bighead carp was cloned and regulation of its gene expression was investigated for understanding phylogenetic divergence and evolution of TSH molecule. The cDNA was obtained from bighead carp pituitary total RNA by reverse transcription and polymerase chain reaction. Oligonucleotide primers were designed from the sequence of common carp. The full length sequence was then obtained by 3' and 5' rapid amplification of cDNA ends (RACE). The full-length sequence consisting of 3' and 5' untranslated regions was 585 bp long. The predicted amino acid sequence consisted of a signal peptide of 19 amino acid residues and a mature TSH beta subunit protein of 131 residues. The coding sequences of the cDNAs showed variable percentage homologies with those of other teleosts and vertebrate species. The predicted amino acid sequence shared 71% identity with rainbow trout and salmon, 90% with goldfish, 50% with eel and 94% with common carp in the mature protein region. The percentages of identity in the same region in comparison with bovine, porcine, rat, mouse, human and chicken were only 39, 42, 41, 40, 45 and 46%, respectively. TSH beta mRNA expression was found only in the pituitary tissue out of other tissues tested as testis, muscle, brain and heart. For the first time, thyrotropin releasing hormone (TRH) and thyroxine (T4) effects on pituitary TSH mRNA expression were tested in teleosts under in vitro conditions. TRH treatment on pituitary cells increased TSH beta mRNA level, while T4 treatment decreased TSH beta mRNA level. The present study provides a direct evidence, for the first time that TRH directly upregulates TSH beta gene expression in teleosts.

Nonmyeloablative allogeneic bone marrow transplantation for orbital granulocytic sarcoma associated with t(8;21)(q22;q22) in acute myeloid leukemia.

We report a nonmyeloablative allogeneic bone marrow transplant (allo-BMT) from an HLA-matched unrelated donor in a case of acute myeloid leukemia (AML), M2 with t(8;21)(q22;q22) and the presence of orbital granulocytic sarcoma (GS), who had residual tumor after conventional chemotherapy. The course of BMT was well tolerated, with no major procedure-related toxicity. The residual orbital GS regressed completely 4 months after BMT. She is currently 19 months post BMT, disease-free. To our knowledge, this is the first reported pediatric patient with AML, GS and t(8;21)(q22;q22) who received a nonmyeloablative allo-BMT.

Sex-specific expression of N-methyl D-aspartate receptor (NMDAR) in the preoptic area of neonatal rats.

The relationship between the N-methyl-D-aspartate receptor (NMDAR) and the sex-specific neurotoxicity of L-glutamate on the preoptic area (POA) of neonatal rats was studied. The NMDAR were semiquantified by western blot analysis. The kinetic change of intracellular calcium and lactate dehydrogenase (LDH) efflux were monitored as rapid and delayed toxic signals, respectively. The results showed that: (1) the NMDAR expression in POA of male rat is higher than that of females; (2) the L-glutamate (500 microM) induced a more significant elevation of intracellular calcium in neuron derived from male rat than that from female; (3) after glutamate-treatment, the LDH efflux in neuronal culture of male rat is higher than that of females. These results suggest that the quantitative difference in NMDAR between male and female rats may contribute to the sex-specific neurotoxicity of L-glutamate on the POA of neonatal rats.

Evaluating the protective role of the olivocochlear bundle against acoustic overexposure in rats by using Fos immunohistochemistry.

Efferent inhibition on the cochlea is suggested as a possible function of the olivocochlear bundle (OCB). Substantial evidence supports the finding that the OCB may protect the inner ear from noise-induced damage. However, there is relatively less known about the effects of noise on the central auditory transmission compared to the effects on the periphery. In the present animal study, two experimental paradigms were designed to analyze the influence of OCB lesion on the central auditory transmission following acoustic overexposure. In order to evaluate the animal's auditory function, its hearing threshold and the tone-evoked Fos expression shown in auditory nuclei were examined. Fos is a protein product of proto-oncogene c-fos. Via appropriate acoustic stimulation, Fos expression reveals the activated neuronal elements along the ascending auditory pathway. Thus, in experiment 1, no exposure sound was introduced and therefore no significant differences were shown in hearing thresholds and Fos expression among all rats, regardless of the status of their OCB. This result indicates that, without acoustic overexposure, OCB lesion caused no significant effect on brainstem auditory transmission. In contrast, in experiment 2, rats were exposed to continuous 8 kHz tones at 85 dB sound pressure level (SPL). A significantly increasing threshold was observed in rats with OCB lesion following an exposure period of 5 or 10 days. In addition, Fos expression was invisible first in rats with OCB lesion following 5-day exposure and almost no Fos expression could be examined in all rats after 10-day exposure. Taken together, the present data demonstrate that damaging the OCB renders an animal more easily vulnerable to acoustic damage than that of rat with intact OCB, and then reduces its cochlear activities, which eventually leads to increasing difficulty to induce tone-evoked Fos expression along the ascending auditory pathway.

Kinetics of germanium dioxide in rats.

The kinetics of germanium dioxide (GeO2) in single dose and repeated exposures were investigated in male Wistar rats. In the single dose GeO2 (100 mg/kg BW, p.o.) exposure study, values of several kinetic parameters were shown as follows, a maximum concentration in serum of 15.5+/-0.7 microg/ml (mean +/- S.E.M.), an absorption half-life of 0.7+/-0.1 h (mean +/- S.E.M.), an elimination half-life of 2.3+/-0.5 h (mean +/- S.E.M.), a distribution of the central compartment Vp (3.1+/-0.3 1, mean +/- S.E.M.), and the apparent volume of distribution of the tissue compartment Vt (8.5+/-2.9 1, mean +/- S.E.M.). In the repeated exposure study, 730+/-92 mg GeO2 in 1 1 double-distilled H2O ( = 100 mg/kg/day) was given daily to rats for 4 weeks (p.o.). After sacrificing the rats, the analysis of tissue distribution showed that GeO2 was accumulated in some important organs or tissues in the body, especially the peripheral nerves and kidney. These results indicate that GeO2 could be absorbed rapidly but had a longer elimination half-life in rats. In addition, GeO2 was accumulated especially in the nerves and kidney following long-term exposure.

Projection space image reconstruction using strip functions to calculate pixels more "natural" for modeling the geometric response of the SPECT collimator.

The spatially varying geometric response of the collimator-detector system in single photon emission computed tomography (SPECT) causes loss in resolution, shape distortions, reconstructed density nonuniformity, and quantitative inaccuracies. A projection space image reconstruction algorithm is used to correct these reconstruction artifacts. The projectors F use strip functions to calculate pixels more "natural" for modeling the two-dimensional (2-D) geometric response of the SPECT collimator transaxially to the axis of rotation. These projectors are defined by summing the intersection of an array of multiple strips rotated at equal angles to approximate the ideal system geometric response of the collimator. Two projection models were evaluated for modeling the system geometric response function. For one projector each strip is of equal weight, for the other projector a Gaussian weighting is used. Parallel beam and fan beam projections of a physical three-dimensional (3-D) Hoffman brain phantom and a Jaszczak cold rod phantom were used to evaluate the geometric response correction. Reconstructions were obtained by using the singular value decomposition (SVD) method and the iterative conjugate gradient algorithm to solve for q in the imaging equation FGq = p, where p is the projection measurement. The projector F included the new models for the geometric response, whereas, the backprojector G did not always model the geometric response in order to increase the computational speed. The final reconstruction was obtained by sampling the backprojection Gq at a discrete array of points. Reconstructions produced by the two proposed projectors showed improved resolution when compared against a unit-strip "natural" pixel model, the conventional image pixelized model with ray tracing to calculate the geometric response, and the filtered backprojection algorithm. When the reconstruction is displayed on fine grid points, the continuity and resolution of the image is preserved without the ring artifacts seen in the unit-strip "natural" pixel model. With present computing power, the geometric response correction using the proposed projection space reconstruction approach is not yet feasible for routine clinical use.

Effect of olivocochlear bundle lesion on locomotor activity in rats.

This study was conducted to investigate the effect of olivocochlear bundle (OCB) lesion on spontaneous locomotor activity in Wistar rats. The OCB is an auditory efferent pathway which originates from the superior olivary complex in the brainstem and terminates within the cochlea. It has an inhibitory effect on the auditory end organs. In the present study, the OCB was damaged at the floor of the fourth ventricle using radiofrequency current. The rats' locomotor activities were then monitored weekly for 2 months using an automated Digiscan activity monitor system. Six behavioral variables were collected and analyzed: horizontal activity (HA), total distance (TD), movement time (MT), vertical activity (VA), stereotypy count (SC), and margin time (MGT). Significant time-dependent increases were noted for HA, TD, VA, and SC following OCB lesion. These results of increasing exploratory and stereotyped behaviors may be caused by the rat experiencing more auditory stimulation than before due to OCB dysfunction and may cause the rat to become more curious to explore its surroundings.

Lactitol-based poly(ether polyol) hydrogels for controlled release chemical and drug delivery systems.

The hydroxyl groups of lactitol were propoxylated to produce poly(ether polyol) (LPEP). The average pK(a) value of hydroxyl groups of the polyol was 1.63. Cross-linked hydrogels were synthesized by esterification with chlorinated poly(ethylene glycol) bis(carboxymethyl) ether (PEGBCOCl). The swelling ratio decreased with increasing cross-linking ratio (PEGBCOCl:LPEP) from 2:1 to 4:1 in the hydrogels and was sensitive to temperature change between 25 and 55 degrees C and concentrations of salt and glucose. The swelling ratio did not change significantly with pH in the range of 4-9. The release profiles of a model active agent, acetylsalicylic acid, from the hydrogels showed that the diffusional release rate had a half-order dependence on time, and the diffusivity decreased with increasing cross-linking ratio. This work demonstrated that LPEP-based hydrogels can be used for controlled delivery of drugs and agrochemicals and the release rates can be controlled with the cross-linking ratio of the hydrogel.

Mechanism and characteristics of protein release from lactitol-based cross-linked hydrogel.

Lactitol-based cross-linked hydrogel was synthesized, and model proteins (alpha-chymotrypsin, beta-lactoglobulin, bovine serum albumin (BSA), and gamma-globulin) were incorporated into the cross-linked hydrogel. The larger-molecular-weight proteins have lower diffusivity (D(e)) in the hydrogel. Increasing temperature accelerated the diffusion rate of proteins; however, the diffusion did not follow the Arrhenius equation at temperatures above 37 degrees C. The swelling ratio of the hydrogel was slightly decreased after heating for 2 h at 37 and 45 degrees C, and significantly reduced after 1 h at 60 degrees C. Therefore, diffusion of beta-lactoglobulin and BSA may be decreased by hydrogel shrinking at temperature over 37 degrees C. The model proteins have high affinities to buffer solution compared to the hydrogel network structure, resulting in high partition coefficients (K > 1) which do not affect the calculation of D(e) values. Incorporated protein release follows the theory of hindered diffusion.

Effects of indoor environmental factors on risk for atopic eczema in a subtropical area.

The objective of this study was to examine the relationship between indoor environmental factors and atopic eczema in a subtropical area. A case-control study was performed using participants from a survey that included 144 school children with atopic eczema and 144 age- and gender-matched controls. The study was confined to 4,164 primary school children aged 6-12 yr attending 8 primary schools in Kaohsiung rural municipalities who participated in the study. Cases of atopic eczema were ascertained by asking whether a physician had ever diagnosed this condition in the child. Information regarding the home environment was obtained using a structured written questionnaire, completed by the parents of the children. Of the many indoor environmental factors included in this study, such as dampness and smoking, none was found to be associated with atopic eczema.

Treatment of childhood acute lymphoblastic leukemia with protocol TCL-842 in Taiwan: the Taiwan Children's Cancer Study Group.

From March 1984 to May 1988, 212 children with acute lymphoblastic leukemia were enrolled on Protocol TCL-842. In all, 68 patients were classified as standard risk (SR), 56 as intermediate risk (IR), and 88 as high risk (HR) groups. Remission induction for all three groups consisted of vincristine (VCR), prednisolone (PRED) and L-asparaginase (L-Asp). One consolidation course with cyclophosphamide (CP) and cytarabine (AraC) was used for the SR and IR groups, and two courses were given to patients in the HR group. Central nervous system prophylaxis was randomized using either cranial irradiation 18 Gy + 5 intrathecal methotrexate (IT MTX) or triple IT with maintenance. Reinforcement cycles were employed periodically during maintenance therapy (basically 6-mercaptopurine+MTX) and varied among the three groups. Four-week oral PRED every 16 weeks was the sole reinforcement agent for SR. Two-week VCR+dexamethasone (DEX)+adriamycin CP cycles were used to reinforce IR and HR at different intervals. Five third-form cycles with VCR+DEX+AraC were used only for HR. Treatment was discontinued after three years in patients who achieved continuous complete remissions (CCR). Eight patients died during the induction phase and eight failed to achieve complete remission (CR). The CR rate for SR was 97%, for IR was 98% and for HR was 83.3%; the overall rate was 91.8%. As of 30 June 1991, 33 patients had dropped out, 12 had died during remission, and 52 had relapsed. Twenty-eight SR, 26 IR, and 29 HR patients remained in CCR with a median follow-up duration of 66 months (38-88 months).(ABSTRACT TRUNCATED AT 250 WORDS)

The suppressive effect of the olivocochlear bundle in rats studied by brainstem auditory evoked potentials following brainstem lesion.

The olivocochlear bundle (OCB) stems from the superior olivary complex in the brainstem and projects to the ipsilateral and contralateral cochlea. Several studies have suggested that the OCB has a suppressive effect on the inner ear by inhibiting the responses of the primary afferent fibers. To evaluate the action of OCB by more available measurement, radiofrequency lesion was applied to 30 Wistar rats which were divided into four groups, a sham group and another three groups with different OCB lesion sites. Consequent changes following OCB lesion were evaluated by measuring the brainstem auditory evoked potentials (BAEPs), which are considered to reflect the auditory brainstem afferent conduction. The amplitudes and latencies did not change significantly after sham treatment. However, although the BAEP peak latencies were not significantly altered after damaging the OCB, the amplitudes of the BAEP waves I to III were augmented significantly. These results indicate that increased neural activities were presented in the auditory nerves, cochlear nucleus and the superior olivary complex upon disinhibition of the OCB. Unilateral OCB lesions predominantly augmented BAEP waveform which was recorded ipsilaterally to the lesion side. Upon lesion of the midline OCB, BAEP recordings on either side showed significant increments in the amplitudes of waves I to III. These findings are compatible with those observed in the cat model and other rodents, and thus confirm that (1) OCB lesion leads to increased amplitudes in some BAEP peaks which were evoked by certain hyperactive auditory nuclei and tracts; and (2) BAEP measurment is a convenient and useful tool for assessing the OCB function.