ABSTRACT
OBJECTIVE: To explore the predictive factors between Meniere's disease (MD) and vestibular migraine (VM) by Gadolinium-enhanced Magnetic resonance imaging (MRI) of the inner ear and Clinical Features. METHODS: Eighty-seven patients (50 MD and 37 VM) underwent intratympanic injection of gadolinium and MRI was performed 24 h later. All patients underwent pure tone audiometry and caloric tests. RESULTS: In the MD group, 46 (92%) of 50 patients developed endolymphatic hydrops, although only 2 (5.4%) in the vestibular migraine (VM) group had positive results groups (p < 0.001). The incidence of migraine was 14% in the MD group and 67.7% in the VM group (p < 0.001). Multivariate logistic regression of the two groups of patients indicated that the greater the sum of the maximum slow phase velocity (SPV) of the ipsilateral ear, the higher the risk of VM occurrence (p = 0.009). The incidence of carsickness was positively correlated with the incidence of VM (p < 0.001) and asymmetric hearing loss (AHL) was negatively correlated with the diagnosis of VM (p = 0.045). CONCLUSION: Gadolinium-enhanced MRI of the inner ear is helpful for the differential diagnosis of VM and MD. Carsickness, decreased AHL, and increased Sum of the maximum SPV in the ipsilateral side (SSPVI) may act as diagnostic predictors of VM. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:426-432, 2024.
Subject(s)
Endolymphatic Hydrops , Hearing Loss , Meniere Disease , Migraine Disorders , Motion Sickness , Humans , Meniere Disease/diagnostic imaging , Meniere Disease/epidemiology , Gadolinium , Vertigo , Endolymphatic Hydrops/diagnostic imaging , Magnetic Resonance Imaging/methods , Migraine Disorders/diagnosis , Migraine Disorders/epidemiologyABSTRACT
Objectives: To compare three methods of scoring endolymphatic hydrops in patients with Ménière's disease in order to assess the correlation between endolymphatic hydrops and auditory characteristics. Methods: A retrospective study of 97 patients with unilateral definite Ménière's disease (DMD) who underwent contrast-enhanced three-dimensional fluid attenuated inversion recovery (3D FLAIR) MRI. Each patient was scored by the Inner Ear Structural Assignment Method (IESAM), the Saccule to utricle area ratio (SURI), and the Four Stage Vestibular Hydrops Grading (FSVH), according to their corresponding axial images. Cohen's Kappa and intra-class correlation coefficient were used for consistency testing, combined with binary logistic regression analysis, to compare the sensitivity and specificity of the three methods. The degree of hydrops in different stages of MD was compared. The correlation between endolymphatic hydrops in the inner ear sub-units and hearing thresholds was further analyzed. Results: The intra- and inter-reader reliability for the scoring of endolymphatic hydrops were excellent. The IESAM had a high diagnostic value for identifying definite Ménière's disease (sensitivity: 86.6%, specificity: 97.9%). The hearing thresholds were correlated with the degree of endolymphatic hydrops. Stages 3 and 4 were more significant for the severity of hydrops than stage 1. Within the subgroups of the Ménière's disease patients, compared with the non-hydrops group and the pure vestibular hydrops (V group), the cochlear combined vestibular hydrops group (CV group) had significantly higher auditory thresholds. The amplitude ratio of electrocochleogram was significantly higher in the affected ear than in the healthy ear. Conclusion: The IESAM is a more sensitive and specific diagnostic scoring method for the diagnosis of DMD. Diagnostic imaging may improve the detection of inner ear hydrops which is correlated with severity of hearing loss. A comprehensive evaluation of the inner ear sub-unit structures maybe necessary.
ABSTRACT
To investigate the application of inner ear 3-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) in patients with sudden sensorineural hearing loss (SSNHL) accompanied by inner ear hemorrhage. A total of 1252 SSNHL patients who were admitted from January 2010 to April 2018 were included in the study. The patients' clinical features, complete blood counts, coagulation profiles, audiometry data, and MRI scans were retrospectively reviewed. Twenty-four patients had high labyrinth signals on inner ear 3D-FLAIR MRI (24/1252, 1.9%) that were diagnosed as inner ear hemorrhage. One patient had endolymphatic hydrops on the contralesional side. In the 24 patients, pure tone audiometry curves revealed profound deafness (19/24) and flat moderate hearing loss (5/24); most patients had associated vertigo (23/24) and tinnitus (19/24). Patients with SSNHL (N = 24) were treated. Sixteen patients had invalid improvement, 3 patients were markedly improved, 4 patients had effective treatment, and only 1 patient was cured, for a therapeutic efficacy of 33.3% (8/24). Follow-up 3D-FLAIR MRI in patients showed absorbance of labyrinthine hemorrhage and disappearance of the high signal intensity in the inner ear within 2 weeks to 4 months. Inner ear 3D-FLAIR MRI indicate that most cases of inner ear hemorrhage are spontaneous and that high labyrinth signals are absorbed within 4 months. The site of labyrinth hemorrhage is irregular and independent of hearing loss. Conventional treatment is not very effective, and an appropriate therapy for SSNHL requires further investigation.
Subject(s)
Ear Diseases/complications , Ear, Inner/diagnostic imaging , Hearing Loss, Sensorineural , Hearing Loss, Sudden , Hemorrhage , Adult , Audiometry, Pure-Tone/methods , China/epidemiology , Ear Diseases/diagnosis , Ear Diseases/physiopathology , Female , Hearing Loss, Sensorineural/diagnosis , Hearing Loss, Sensorineural/etiology , Hearing Loss, Sudden/diagnosis , Hearing Loss, Sudden/epidemiology , Hearing Loss, Sudden/etiology , Hemorrhage/complications , Hemorrhage/diagnosis , Hemorrhage/physiopathology , Humans , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Male , Middle Aged , Retrospective Studies , Tinnitus/diagnosis , Vertigo/diagnosisABSTRACT
OBJECTIVE: To investigate the clinical features, diagnosis and prognosis of sudden sensorineural hearing loss accompanied with inner ear hemorrhage. METHODS: Eleven cases of sudden sensorineural hearing loss accompanied with inner ear hemorrhage were retrospectively analyzed, including clinical manifestation, hematological and audiological examinations, as well as characteristics of inner ear three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI). RESULTS: Eleven cases of sudden hearing loss with inner ear hemorrhage were accompanied by varying degrees of vertigo, lasting from several minutes to several hours, nine of whom had persistent tinnitus. The audiometry curves of the 11 cases included total deafness or flat descending type. The inner ear 3D-FLAIR MRI studies revealed abnormal high signals at different positions of the inner ear, one case with endolymphatic hydrops. After the treatment, seven cases were invalid, two cases had notable effect, and two cases were effective. CONCLUSIONS: Abnormal high signals in the inner ear were sensitively detected by 3D-FLAIR MRI sequence, which was applied for the diagnosis of the sudden hearing loss accompanied with inner ear hemorrhage. The effect of conventional treatment was not good and the appropriate treatments for this type of sudden hearing loss need further investigation.
Subject(s)
Ear, Inner/physiopathology , Hearing Loss, Sensorineural/complications , Hearing Loss, Sudden/complications , Hemorrhage/complications , Audiometry , Deafness/complications , Deafness/diagnosis , Endolymphatic Hydrops/complications , Hearing Loss, Sensorineural/diagnosis , Hearing Loss, Sudden/diagnosis , Humans , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Prognosis , Retrospective Studies , Tinnitus/complications , Vertigo/complicationsABSTRACT
OBJECTIVE: To investigate imaging and audiology features of temporal bone and analyze the classification and prevalence of inner ear abnormalities in children with sensorineural hearing loss. METHOD: Children who were diagnosed with sensorineural hearing loss were examined by high resolution CT and the inner ear fluid of MRI. And each chart was retrospectively reviewed to determine the imaging and audiology features. RESULT: There were 125 patients(232 ears) found with inner ear malformation in 590 children with SNHL. About 21.71% of the inner ear malformation occurred in severe and profound hearing loss ears, and 12.85% occurred in r moderate hearing loss ears. The inner ear malformation rate in normal hearing ears were 13.59%. CONCLUSION: CT and MRI examinations of temporal bone are important diagnostic tools to indentify inner ear malformations. Inner ear malformations are almost bilateral and hearing loss are profoud. Cochleo-vestibular malformations and large vestibular aqueduct are the 2 most frequent deformities. Among the children with SNHL, deformity rate in the severe and profound hearing loss ears is higher than that in moderate hearing loss ear. Inner ear malformations can exist in people with normal hearing.
Subject(s)
Audiology , Ear, Inner/abnormalities , Hearing Loss, Sensorineural/congenital , Hearing Loss, Sensorineural/pathology , Magnetic Resonance Imaging , Tomography, X-Ray Computed , Child , Humans , Prevalence , Retrospective Studies , Temporal Bone , Vestibular Aqueduct/abnormalitiesABSTRACT
PURPOSE: The aim of the study is to probe whether intratympanically gadolinium contrast-enhanced three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging, together with magnetic resonance imaging scoring system of the perilymphatic space, had advantages in diagnosing patients with bilateral Meniere's disease. MATERIALS AND METHODS: Eight patients diagnosed as 'definite' bilateral Meniere's disease and two patients considered as 'possible' Meniere's disease were selected for the current study. All ten patients underwent caloric test, vestibular evoked myogenic potential and intratympanically gadolinium-enhanced magnetic resonance imaging. The perilymphatic space of scanned images were analyzed to investigate the presence of endolymphatic hydrops. The positive rates (bilaterally abnormal patients/patients tested) of the three examinations in the eight patients with bilateral Meniere's disease were calculated respectively. We also selected eight patients with unilateral Meniere's disease as the control group by the method of simple random sampling without replacement. RESULTS: According to the magnetic resonance imaging scoring system, 100% (8/8) of the patients with bilateral Meniere's disease had bilateral endolymphatic hydrops. The positive rates of vestibular evoked myogenic potential and caloric test were 50% (4/8) and 25% (2/8), respectively. There was a significant difference among the positive rates of the three examinations (P<.05). Two patients with 'possible' Meniere's disease had bilateral endolymphatic hydrops by magnetic resonance imaging. Eight patients with unilateral Meniere's disease displayed endolymphatic hydrops of the affected ears. CONCLUSIONS: Intratympanically gadolinium-enhanced magnetic resonance imaging has a relatively high positive rate of exhibiting bilateral endolymphatic hydrops. This technique with the magnetic resonance imaging scoring system is valuable when diagnosing bilateral Meniere's disease.
Subject(s)
Endolymphatic Hydrops/diagnosis , Magnetic Resonance Imaging/methods , Adult , Audiometry, Pure-Tone , Caloric Tests , Contrast Media , Female , Gadolinium DTPA , Humans , Image Processing, Computer-Assisted , Male , Meniere Disease/diagnosis , Middle Aged , Tympanic MembraneABSTRACT
OBJECTIVE: To introduce the efficacy of three surgical options for juvenile nasopharyngeal angiofibroma (JNA) resection, and causes of operative bleeding. METHOD: Retrospective analysis of 36 JNAs,three surgical options were used to resect the tumor. There were 15 cases of Class I tumors , using endoscopic nasal cavity approach. Eighteen cases of class II tumors, via extended Caldwell-Luk incision, using the transantral-infratemporal fosse-nasal cavity combined approach for tumor resection. Three cases of class III tumors, the combined intracranial and extra-cranial approach was used to resect the tumor. Meanwhile, report six typical cases for reference. RESULT: Fifteen (15/36) cases of class I tumors, 14 cases were completely resected for the first time without recurrence, 1 recurrence case was re-resected using the same approach. Eighteen (18/36) cases of class II tumors, 13 cases were completely resected for the first time without recurrence, 5 recurrence cases were re-resected totally. Three (3/36) cases of class III were not completely removed, and underwent about 40 Gy radiotherapy with good effects. CONCLUSION: Using these three surgical options can effectively remove different types of JNA. When necessary, the intracranial residue can use radiotherapy. Under direct vision to separate the tumor, and effective hemostasis play crucial roles for complete removal of the tumor.
Subject(s)
Angiofibroma/surgery , Blood Loss, Surgical , Nasopharyngeal Neoplasms/surgery , Adolescent , Child , Female , Humans , Male , Retrospective Studies , Treatment Outcome , Young AdultABSTRACT
OBJECTIVES: To describe a clear and simplified classification system for juvenile nasopharyngeal angiofibroma (JNA), and to describe suitable management options. STUDY DESIGN: Retrospective medical record review. METHODS: The clinical and imaging materials of 51 cases of JNA diagnosed at our hospital between 1981 and 2011 were collected and studied. Based on our experiences, we prefer to divide JNAs into three types. Type I includes JNAs fundamentally localized to the nasal cavity, paranasal sinus, nasopharynx, or pterygopalatine fossa. Type II is a JNA extending into the infratemporal fossa, cheek region, or orbital cavity, with anterior and/or minimal middle cranial fossa extension but intact dura mater. Type III is a calabash-like massive tumor lobe in the middle cranial fossa. The management and prognosis for the three types of JNA were compared and evaluated. RESULTS: Among cases of type I JNA (n=16), the entire mass was removed by the initial operation in 15 cases and by a repeat operation in 1 case. Among cases of type II JNA (n=29), the entire mass was removed by the first operation in 24 cases and by repeat operation in 5 cases. In cases of type III JNA (n=6), the huge calabash-like lobe in the middle cranial fossa could not be completely excised; 4 cases underwent radiotherapy and 2 cases were lost to follow-up. CONCLUSIONS: 1) The transnasal cavity approach with endoscopic guidance is suitable for type I JNA resection. 2) The transantral-infratemporal fossa-nasal cavity combined approach is reliable for resection of a type II JNA, which extends into the deep anterior cranial fossa and/or minimally into the middle cranial fossa, with intact dura mater. 3) The complete removal of a type III JNA is difficult, even through a combined extracranial and intracranial approach. Radiotherapy is useful for treating the residual intracranial tumor. The successful or failed experiences of 6 typical cases prove that this revised classification system is reasonable and reliable.
Subject(s)
Angiofibroma/classification , Angiofibroma/therapy , Nasopharyngeal Neoplasms/classification , Nasopharyngeal Neoplasms/surgery , Otorhinolaryngologic Surgical Procedures/methods , Adolescent , Adult , Angiofibroma/diagnostic imaging , Child , Endoscopy/methods , Female , Humans , Male , Nasopharyngeal Neoplasms/diagnostic imaging , Prognosis , Radiography , Retrospective Studies , Young AdultABSTRACT
OBJECTIVES/HYPOTHESIS: To investigate endolymphatic space images in patients with idiopathic sudden sensorineural hearing loss (ISNHL) and vertigo using three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI). STUDY DESIGN: This is a prospective study of an analysis using the imaging technology of 3D-FLAIR MRI for patients with ISNHL and vertigo. METHODS: 3D-FLAIR MRI was performed 24 hours after intratympanic injection of gadolinium-diethylenetriamine penta-acetic acid. RESULTS: In four of seven cases of ISNHL with vertigo, endolymphatic hydrops were confirmed in the cochlea and/or the vestibule of the affected ears. CONCLUSIONS: The results of the study imply that there may be some relationship between endolymphatic hydrops and ISNHL with vertigo.
Subject(s)
Endolymphatic Hydrops/diagnosis , Hearing Loss, Sensorineural/diagnosis , Hearing Loss, Sudden/diagnosis , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Vestibule, Labyrinth/pathology , Adult , Contrast Media , Endolymphatic Hydrops/complications , Female , Gadolinium , Gadolinium DTPA , Hearing Loss, Sensorineural/complications , Hearing Loss, Sudden/complications , Humans , Male , Middle Aged , Prospective Studies , Vertigo/complicationsABSTRACT
OBJECTIVE: To explore the positive visualization rate of endolymph space in Meniere's disease (MD) by three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI) and assess its diagnostic value of MD. METHODS: 3D-FLAIR MRI was performed at 24 h after an intratympanic injection of gadolinium diethylenetriamine penta-acetic acid in 51 MD patients. Then the examination results were summarized, analyzed and compared with those of vestibular evoked myogenic potential (VEMP) and glycerol tests. RESULTS: Gadolinium was found in perilymph inside inner ear. Furthermore the border between perilymph and endolymph was visible so that endolymphatic space was distinctly visualized on 3D-FLAIR MRI. Forty-nine (96.1%) patients demonstrated the signs of endolymphatic hydrops. Statistically significant differences existed between the results of 3D-FLAIR MRI and those of VEMP and glycerol tests (P < 0.05). No complication of tympanic membrane perforation or infection was observed. CONCLUSION: After an intratympanic injection of gadolinium, 3D-FLAIR MRI has a higher positive rate in MD patients. Though as an invasive procedure, it has fewer side effects and will become an important diagnostic tool for MD.
Subject(s)
Gadolinium , Magnetic Resonance Imaging/methods , Meniere Disease/diagnosis , Adult , Aged , Contrast Media , Ear, Inner , Endolymphatic Hydrops , Female , Humans , Male , Middle Aged , Young AdultABSTRACT
20(S)-protopanaxadiol (PPD(S)) and 20(R)-protopanaxadiol (PPD(R)), the main metabolites of ginsenosides Rg3(S) and Rg3(R) in black ginseng, are potential candidates for anti-cancer therapy due to their pharmacological activities such as anti-tumor properties. In the present study, we report the preparation of PPD(S, R) by a combination of steaming and biotransformation treatments from ginseng. Aspergillus niger was isolated from soil and showed a strong ability to transform Rg3(S, R) into PPD(S, R) with 100% conversion. Furthermore, the enzymatic reactions were analyzed by reversed-phase HPLC, showing the biotransformation pathways: Rg3(S)-->Rh2(S)-->PPD(S) and Rg3(R)-->Rh2(R)-->PPD(R), respectively. In addition, 12 ginsenosides including 3 pairs of epimers, namely Rg3(S), Rg3(R), Rh2(S), Rh2(R), PPD(S) and PPD(R), were simultaneously determined by reversed-phase HPLC. Our study may be highly applicable for the preparation of PPD(S) and PPD(R) for medicinal purposes and also for commercial use.
Subject(s)
Aspergillus niger/enzymology , Ginsenosides/chemistry , Ginsenosides/metabolism , Panax/metabolism , Sapogenins/chemistry , Sapogenins/metabolism , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Biotransformation , Chromatography, High Pressure Liquid , Chromatography, Reverse-Phase , StereoisomerismABSTRACT
OBJECTIVE: To our knowledge, study of the intraoperative profuse bleeding of pterygoid venous plexus (PVP) in large nasopharyngeal angiofibroma resection has not yet been reported. Attention should be paid to this topic in clinical practice. METHOD: From 1981 to 2009, 44 cases of JNAs were treated in our hospital. Twenty-six of 44 cases were large nasopharyngeal angiofibromas according to the Fisch classification system(Fisch type III 16, type IV 10). The amount of intraoperative blood loss in these 26 cases varied from 200 ml to 5200 ml. Factors influencing intraoperative bleeding of 26 large nasopharyngeal angiofibroma resections were analyzed retrospectively. The intra-operative observations and imaging data of three typical cases were hereby studied. RESULT: After embolization of the tumor-supplying branches of the external carotid artery(ECA), both the intraoperative observations and imaging data demonstrated that the pterygoid venous plexus (PVP) played a crucial role in intraoperative hemorrhage. CONCLUSION: PVP in the infratemporal fossa communicates with craniofacial veins. There is no valve between these veins. Once PVP is seriously damaged, venous blood of all craniofacial veins will flow out profusely. In the first operation, the intact PVP in the fatty pad generally can be identified and separated from the tumor by delicate surgical managements. If an unsuccessful operation due to serious hemorrhage had been done previously, then scar tissue might tightly adhere with PVP, tumor and the pterygoid muscles, and separation of the tumor from PVP without bleeding is more difficult. Appropriate surgical approach and correct hemostatic procedure of every bleeding point should be done carefully under direct vision. Using finger or instrument for quick blind dissection should be prohibited.
Subject(s)
Angiofibroma/surgery , Nasopharyngeal Neoplasms/surgery , Veins/surgery , Adolescent , Angiofibroma/pathology , Blood Loss, Surgical , Hemorrhage/prevention & control , Humans , Male , Nasopharyngeal Neoplasms/pathology , Retrospective Studies , Young AdultABSTRACT
A high-performance liquid chromatographic method with evaporative light scattering detection (HPLC-ELSD) has been developed to identify and quantify 19 ginsenosides (Rg(1), Re, Rf, Rb(1), Rc, Rb(2), Rd, F(4), Rg(6), Rk(3), Rh(4), 20(S)-, 20(R)-Rg(3), 20(S)-, 20(R)-Rs(3), Rk(1), Rg(5), Rs(4), and Rs(5)) in black ginseng (BG, Korean white ginseng that was subjected to nine cycles of steam treatment). Ultrasonication is employed for sample preparation, and the analysis is achieved on a Discovery C(18) column using gradient elution of CH(3)CN-H(2)O-CH(3)COOH without buffer in 40min. The method was validated by linearity (r(2)> or =0.9994), precision (92.0-107.5%), intra- and inter-day accuracy (R.S.D.<3.21%), and limit of detection (LOD< or =93ng). The quantification method was applied to analyze the composition of ginsenosides in Korean white, red, and black ginsengs. During the preparatory process of BG, ginsenosides transform into constituents of low polarity by hydrolysis, isomerization, and dehydration at C-20, and hydrolysis also occurs at C-3 or C-6. The validated HPLC method is expected to provide the basis for the quality assessment of ginseng products.
Subject(s)
Chromatography, High Pressure Liquid/methods , Ginsenosides/analysis , Panax/chemistry , Reproducibility of ResultsABSTRACT
To optimize ginsenosides hydrolyzing beta-glucosidase production from Aspergillus niger, response surface methodology was carried out in two stages. The Plackett-Burman design was achieved to screen the important variables that influence beta-glucosidase production. Among 10 variables (wheat bran, soybean powder, CaCl(2), ginsenosides, KH(2)PO(4), MgSO(4), polyethylene glycol (PEG), medium volume, inoculum size, and stirring speed), it was found that wheat bran, KH(2)PO(4), and stirring speed had significant effect on beta-glucosidase activity due to very low p-values (p<0.05). Subsequently, wheat bran, KH(2)PO(4), and stirring speed were further optimized using central composite design. The optimal beta-glucosidase production was predicted to be 4650.14 U/ml with the combination of factors (wheat bran, 34.51 g/l; KH(2)PO(4), 1.78 g/l; stirring speed, 161.60 rpm/min). Finally, under optimal fermentation conditions, ginsenoside Rb(1) was converted to Rd and F(2) by A. niger within 10 min. Little compound K was detected at 30 min, and finally F(2) was completely transformed to compound K within 8 h. The putative conversion pathway of Rb(1) by A. niger was Rb(1), Rd, F(2), and compound K.
Subject(s)
Aspergillus niger/drug effects , Aspergillus niger/enzymology , Ginsenosides/metabolism , beta-Glucosidase/biosynthesis , Chromatography, High Pressure Liquid , Culture Media , Data Interpretation, Statistical , Drug Evaluation, Preclinical , Spectrophotometry, Ultraviolet , Stimulation, Chemical , Triticum/chemistryABSTRACT
The expression and localization of insulin-like growth factor-I (IGF-I) in the four parts (tip, upper, mid and base) of the red deer antler has been extensively investigated. We used reverse transcriptase polymerase chain reaction (RT-PCR) and real-time reverse transcriptase polymerase chain reaction (real time RT-PCR), in situ hybridization, immunohistochemistry and Western blot techniques to localize IGF-I messenger ribonucleic acid (mRNA) and IGF-I peptide in the four parts of the antler. The specific sequence encoding IGF-I was detected by RT-PCR in all of the four specimens, and the 395 bp IGF-I sequence from the red deer antler was shown to have very high homology with human, goat and mouse IGF-I. In situ hybridization and immunohistochemistry results demonstrated that the expression of IGF-I occurred in chondrocytes and osteoblasts in the tip and upper parts of the antler. However, IGF-I was only detectable in osteoblasts around the bone in the mid and base parts. There were significant differences in the intensity of the signal obtained with the IGF-I probe in the tip, upper, mid and base tissues. The Western blot analysis also provided evidence that IGF-I expression was localized differentially in the four parts of the deer antler. This study indicates that antler tissue is an essential part of the IGF system, which is involved in the regulation of the growth of red deer antlers. The specific expression of IGF-I in the four parts of the deer antler suggests that the IGF-I molecule is present at significantly different levels throughout the deer antler development and regeneration processes. Localization of IGF-I in chondrocytes and osteoblasts suggests that IGF-I may play an important role in cartilage and bone formation. In addition, it may have a variety of biophysical effects that influence the rapid growth of deer antlers.