Volume 117  ·   Issue 05  ·  2004

Background Daxx has been identified as a nuclear protein that involves in apoptosis and transcriptional repression. Daxx co-localizes with the promyelocytic leukemia (PML) protein and regulates transcription. Human Daxx (hDaxx) is a protein that functions as a transcriptional regulation through its interaction with some DNA-associated proteins. The aim of this study was to explore the transcriptional regulatory effect of hDaxx interacting with adenovirus (Ad) 12 E1 B (Ad12E1B) 55-kDa oncoprotein. Methods The co-localization of hDaxx-Ad12E1B or hDaxx-PML protein in the nucleus was observed under a confocal microscope. Interaction of hDaxx and Ad12E1B was analyzed by yeast two-hybrid assay. Direct binding of hDaxx and Ad12E1B was analyzed using coimmunoprecipitation and Western blot in vivo and in vitro. The activity of a luciferase reporter gene, which was regulated by an hDaxx modulated thymidine kinase (TK) promoter, was detected in an automat luminometer. Results Ad12E1B, which co-localized with hDaxx in the nuclei of G401-CC3 cells, disrupted the co-localization of hDaxx and PML in the PML oncogenic domains (PODs). hDaxx bound directly to Ad12E1B in vivo and in vitro. hDaxx interacted with Ad12E1B along its full length. Ad12E1B enhanced transcriptional repression activity of hDaxx. Conclusion Ad12E1B disrupts the co-localization of hDaxx with PML in PODs and enhances transcriptional repression activity of hDaxx. Chin Med J 2004; 117(5):753-757

Background Hereditary nonpolyposis colorectal cancer (HNPPC) is one of the most common genetic syndrome related with mutation of human mismatch repair genes. This study was to evaluate the clinical significance of suspected hereditary nonpolyposis colorectal cancer (sHNPCC) criteria I and the clinical and genetic features of International Collaborative Group-HNPCC (ICG-HNPCC) and sHNPCC families. Methods Twenty-nine ICG-HNPCC families fulfilling the Amsterdam criteria and 34 sHNPCC families fulfilling the sHNPCC criteria I were collected. PCR-SSCP and DNA sequencing analysis were employed to screen the germline mutations of the hMLH1 and hMSH2 genes in these families. Results The ICG group had more colorectal cancer (CRC) patients per family than did the suspected group (P <0. 05). No statistical difference was observed in Lynch classification and familial tumor spectrum. In both groups of families, colorectal cancer was the most frequent malignancy, and carcinomas of the stomach, pancreas and uterus were the three most common extracolonic malignancies. Mutation screening showed that ICG-HNPCC and sHNPCC families had a similar mutation rate (31. 0% vs 29. 4%, P > 0. 05), mutation type, and mutation distribution. Comparison of the families with and without mutation showed no significant difference in CRC patients per family, Lynch classification, and tumor spectrum. Conclusions ICG-HNPCC and sHNPCC families that have similar clinical manifestations and genetic basis indicate a similar nature for cancer development. The application of sHNPCC criteria I will facilitate clinical diagnosis and treatment of small families. Chin Med J 2004; 117(5):748-752

Background Does klotho (KL) protein exist in human serum, and is there any correlation between KL protein in serum with human aging? In order to answer those questions, we identified KL protein in human serum and established the correlation between KL protein in human serum and aging. Methods We prepared a polyclonal antibody against human KL protein that was able to recognize the C-terminal of human secreted KL protein. Western blot and enzyme-linked immunosorbent assay (ELISA) were used to identify KL protein in human serum. Results In Western blot, the antibody specifically recognized a 60-kD KL protein in both human and mice serum. The population aged from 0 to 91 years screened by ELISA revealed that the level of serum KL declined while age increased, though each individual level was variable and that the trend of decreasing in serum KL had no difference in sex. Conclusion Our data suggest that KL is a serum factor related to human aging. Chin Med J 2004; 117(5):742-747

Background The ability of patients to discriminate thickness can change with time after the insertion of new complete dentures, and this adaptation may differ according to the experiences of the patients. If so, an education program to reinforce the oral functions may be needed. This study was to evaluate patients' ability to discriminate thickness by comparing experienced and non-experienced denture wearers after the insertion of new complete dentures. Methods Forty edentulous patients with a skeletal Class I jaw relationship without any temporomandibular disturbances were in the study. After insertion of new complete dentures, all patients were tested for discrimination threshold for interocclusal thickness. The thickness perception test was repeated on days 1, 7, and 30 after the insertion of new dentures. The discriminatory ability was assessed with steel and aluminium foils placed between the upper and lower central incisor teeth. The records included the duration of wearing dentures. The data were subjected to statistical analysis of two-way ANOVA, multiple comparison test and Student's t test. Results Discrimination of tactile ability significantly increased over 30 days in experienced denture wearers as compared with non-experienced patients (P < 0. 001). The difference in thickness perception threshold was statistically significant between the two groups (P <0. 001). Conclusion Adaptation and denture experience can affect thickness discrimination of complete denture wearers. Chin Med J 2004; 117(5):738-741

Background The temporal bone has the most complicated anatomic feature among the whole human body, which always challenges otolaryngologists. This study was to study three-dimensional (3D) morphology of the temporal bone and the ear by means of a computer image processing technique, for the purpose of providing a 3D image to help in pathological, diagnostic and surgical procedures. Methods Forty sets of temporal bone celloidin serial sections with reference points were prepared and the contours of selected structures and reference points were entered into a graphics programme. The technique of computer-aided 3D reconstruction was applied to obtain 3D images and parameters of the temporal bones and the ears. Stereo views of the ossicles (n = 5), the facial nerves (n = 11), the posterior tympanic sinuses (n =11), the posterior ampullary nerves (n = 4), the endolymphatic ducts and sacs (n = 5), and the bony and membranous labyrinth (n =1) were reconstructed. Results Three-dimensional images, including the cochlea, the ossicles, the nerves, the tendons and the endolymphatic fluid system in the temporal bone, were obtained. Stereo picture pairs and 3D parameters of spatial dimensions, angle and volume for these reconstructed structures were calculated. The arrangement of the ossicles, spatial relationship of the bony and membranous labyrinth, the whole course of the facial nerves, the endolymphatic sac and posterior tympanic cavity were clearly observable. Stereo picture pairs made the spatial relationships among the abovementioned structures much clearer. The operation of the posterior ampullary nerve transection was designed and simulated on the graphic computer based on 3D anatomic investigations. Conclusion The technique of computer-aided 3D reconstruction provides a new tool to observe the morphology of the temporal bone and thus may allow design and study of new surgical approaches. Chin Med J 2004; 117(5):733-737

Background Congenital cataract is a sight-threatening disease that affects about 1 - 6 cases per 10 000 live births and causes 10% -30% of all blindness in children. About 25% of all cases are due to genetic defects. We identified autosomal dominant congenital coralliform cataracts-related genetic defect in a four-generation Chinese family. Methods Complete ophthalmological examinations were performed prior to lens extraction. Lens samples were then studied by electron microscopy. Genomic DNA from family members were examined using whole-genomic linkage analysis, with two-point logarithm of odds (LOD) scores calculated using the Linkage program package (version 5. 1). Mutation analysis of candidate genes was performed by direct sequencing. Finally, a three-dimensional protein model was predicted using Swiss-Model (version 2. 0). Results Eleven of the 23 examined individuals had congenital cataracts. Ultrastructure studies revealed crystal deposits in the lens, and granules extensively dispersed in transformed lens fiber cells. The maximum two-point LOD score, 3. 5 at θ = 0. 1, was obtained for the marker D2S325. Mutation analysis of the γ-crystallin (CRYG) gene cluster identified a mutation (P23T) in exon 2 of γD-crystallin (CRYGD). Protein structure modeling demonstrated that the P23T mutation caused a subtle change on the surface of the γD protein. Conclusions The results suggest that the coralliform cataract phenotype is due to a mutated CRYGD gene, and that this sequence change is identical to one reported by Santhiya to be related to another distinct clinical condition, lamellar cataract. This study provides evidence that this same genetic defect may be associated with a different phenotype. This is the first report identifying the genetic defect associated with an autosomal dominant congenital coralliform cataract. Chin Med J 2004; 117(5):727-732

Background Pax-6 gene plays an important role in the process of eye development. This study was to determine the role of pax-6 in the axial myopia produced by hyperopic optical defocus and form deprivation in infant monkeys. Methods Among seven normal infant rhesus monkeys (aged 1 to 1. 5 months), five wore -3. 00 D spectacle lenses over their right eyes and zero-powered lenses over their left eyes. Monocular form deprivation was produced by eyelid fusion in two monkeys. Ten weeks later, the monkeys were sacrificed by an overdose of barbiturates and their eyes were removed immediately. A 5 mm x5 mm button of retina and sclera was taken from the posterior poles along with a 4-mm optic nerve. RNA was isolated separately from each of these three types of tissues. After that, reverse transcription polymerase chain reaction (RT-PCR) was used for determining gene expression in the retina, sclera and optic nerve. Semi-quantitative analyses were performed on the PGR products. Results As expected, the optically induced hyperopic defocus and the form deprivation produced myopic growth. For the lens-treatment monkeys, pax-6 gene expression in the retinas of the defocused eyes was significantly higher than in the retinas of the left eyes (t = 5. 703, P = 0. 005). However, there were no analogous significant differences between pax-6 expression in the scleras or the optic nerves. For the two form-deprived monkeys, there were no obvious differences in pax-6 gene expression in the retinas or the optic nerves. Conclusion The result that the expression of pax-6 was enhanced by hyperopic defocus in the infant monkey retina suggests that pax-6 may be involved in vision-dependent eye growth and emmetropization. Chin Med J 2004; 117(5):722-726

Background Caspases are important in the signaling pathway of cellular apoptosis. Caspase-3 protein expression has been shown to increase and parallel to neuronal apoptosis in retinal ischemia injury. This study was to determine whether caspase-1 is involved in neuronal cell death or in retinal ischemia and reperfusion injury. Methods In twenty-one adult mice, ischemia was induced by increasing the intraocular pressure. The animals were sacrificed at 1 hour, 3 hours, 6 hours, 1 day, 3 days and 7 days after reperfusion. Frozen sections were used for caspase-1 immunostaining and TUNEL labeling. Results In normal retina, no caspase-1 positive cells were seen. One hour after ischemia, numerous positive cells were noted in the ganglion cell layer (GCL) and inner side of inner nuclear layer (INL). At 3 hours, caspase-1 positive cells continued to increase and peaked at 6 hours, then decreased significantly at 1 day. TUNEL positive cells were detected at 3 hours and peaked at 1 day after ischemia. Double labeling of caspase-1 and TUNEL only showed few cells with co-localization after ischemia. Conclusion Caspase-1 immunoreactivity preceds to the TUNEL labeling in the GCL and INL after retinal ischemia and reperfusion injury and its early activation may play an important role in the initiation of neuronal apoptosis. Chin Med J 2004; 117(5):717-721

Background Immune rejection is the main reason of grafts failure after corneal transplantation. This study was to determine whether interlerkin-1 receptor antagonist (IL-1ra) eye drops could prolong corneal allografts survival in high-risk corneal orthotopic allotransplantation in rat model and to study the effect of IL-1 ra on the expression of CD1-positive cells in the grafts. Methods For all experiments, the Sprague-Dawley (SD) rats' corneas were transplanted into Wistar rats' eyes. High-risk transplants included those that had been sutured into Wistar recipient beds with corneal neovascularization induced by placement of three interrupted sutures in the host cornea 7 days earlier. All the animals were divided, in a masked fashion, into three treatment groups and one control group. Each treatment group received IL-1 ra eye drops of different concentrations (1 mg/ml, 3 mg/ml, or 5 mg/ml, respectively) four times a day for 30 days. The control group received 0. 9% normal saline (NS) eye drops in the same way as the treatment groups. All allografts were evaluated for signs of rejection from the first day after surgery. Ten days later, corneal specimens were processed to examine the expression of CD1-positive cells and histopathological changes. Results The survival time of the transplants was 5. 80 ±0. 79, 5. 89 ±1. 05, 6. 78 ±0. 83, and 9. 00 ±2. 36 days respectively in the control or three treatment groups. Compared with the control group, 1 mg/ml IL-1 ra eye drop did not prolong the survival time of the allografts (t = 0. 210, P > 0. 05). However, 3 mg/ml and 5 mg/ml IL-1 ra eye drop did prolong the survival time of the grafts (t≥2.627, P<0. 05), with the latter showing more obvious effect. Immunohistochemical examinations showed a significant decrease in inflammatory cell and CD1-positive cell infiltration in IL-1 ra treated groups compared with the control group. Conclusions IL-1 ra can promote corneal allograft survival in a dose-dependant manner by reducing the infiltration of CD1-positive cells in high-risk corneal transplantation. Chin Med J 2004; 117(5):711-716

Background Primary open-angle glaucoma (POAG) is characterized by optic nerve damage and consists of a group of genetically heterogeneous disorders. This study was to investigate the associations of genetic and environmental factors with POAG in a hospital-based Chinese population. Methods Thirty-two adult onset POAG patients and 96 age-sex matched control subjects were studied by multivariable logistic regression analysis for the relationships between POAG and its risk factors including family history, diabetes, hypertension, cardiovascular diseases, cigarette smoking, alcohol consumption and polymorphisms of the myocilin and the optineurin genes. Results Univariate analysis showed that POAG was related to family history, cardiovascular disease, alcohol consumption and a myocilin sequence alteration (T353I) (P <0. 04). Multivariable logistic regression analysis confirmed that POAG was significantly associated with family history (OR = 20. 2), hypertension (OR = 3. 58), cigarette smoking (OR = 10. 8), alcohol consumption (OR = 0. 028) and T353I (OR = 6. 03, all P<0. 05). Conclusions Family history, hypertension, cigarette smoking and T353I in the myocilin gene are risk factors for POAG. Alcohol consumption, however, has a protective effect. Chin Med J 2004; 117(5):706-710