首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Myelodysplastic syndrome (MDS) is clonal disease featured by ineffective haematopoiesis and potential progression into acute myeloid leukaemia (AML). At present, the risk stratification and prognosis of MDS need to be further optimized. A prognostic model was constructed by the least absolute shrinkage and selection operator (LASSO) regression analysis for MDS patients based on the identified metabolic gene panel in training cohort, followed by external validation in an independent cohort. The patients with lower risk had better prognosis than patients with higher risk. The constructed model was verified as an independent prognostic factor for MDS patients with hazard ratios of 3.721 (1.814-7.630) and 2.047 (1.013-4.138) in the training cohort and validation cohort, respectively. The AUC of 3-year overall survival was 0.846 and 0.743 in the training cohort and validation cohort, respectively. The high-risk score was significantly related to other clinical prognostic characteristics, including higher bone marrow blast cells and lower absolute neutrophil count. Moreover, gene set enrichment analyses (GSEA) showed several significantly enriched pathways, with potential indication of the pathogenesis. In this study, we identified a novel stable metabolic panel, which might not only reveal the dysregulated metabolic microenvironment, but can be used to predict the prognosis of MDS.  相似文献   

2.
Retrospective analysis has included 323 patients with acute nonlymphocytic leukaemia. The comparable patient groups were treated since 1981, according to protocols used by the Polish Acute Leukaemia Group. The prognostic value for achieving complete remission and survival of 67 pre-treatment factors (42 quantitative and 25 qualitative) was evaluated. The most important 9 parameters were scored according to their prognostic value as follows: age, percent of blasts in bone marrow, peripheral blood blast count, morphological subtype, percent of granulocytes in bone marrow, percent of blasts with CD-15 antigen, thrombocyte count, spleen/liver enlargement, CSF protein levels. Proposed scoring system enables classification of ANLL patients to a standard and high risk groups.  相似文献   

3.
《Biomarkers》2013,18(7):642-647
Context: Current laboratory parameters provide limited information about the prognosis of severely injured patients; therefore, novel laboratory parameters are needed.

Materials and methods: We compared the morphological parameters of neutrophils and lymphocytes, and white blood cell (WBC) differential count between survivors and nonsurvivors within 7 days after admission. Multiple logistic regression analysis was conducted to identify independent prognostic factors for 7-day in-hospital mortality.

Results: Neutrophil cell size was significantly different between survivors and nonsurvivors (p = 0.04), whereas WBC count and differential were not significantly different. Multiple logistic regression showed that neutrophil cell size was a significant predictor of poor outcome.

Conclusions: Neutrophil cell size at admission is a prognostic factor for 7-day in-hospital mortality in severely injured trauma patients, whereas conventional WBC count and differential have no prognostic value.  相似文献   

4.
BackgroundThere is an urgent need for a robust, clinically useful predictive model for survival in a heterogeneous group of patients with metastatic cancer referred to radiation oncology.MethodsFrom May 2012 to August 2013, 143 consecutive patients with stage IV cancer were prospectively evaluated by a single radiation oncologist. We retrospectively analyzed the effect of 29 patient, laboratory and tumor-related prognostic factors on overall survival using univariate analysis. Variables that were statistically significant on univariate analysis were entered into a multivariable Cox regression to identify independent predictors of overall survival.ResultsThe median overall survival was 5.5 months. Four prognostic factors significantly predicted survival on multivariable analysis including ECOG performance status (0–1 vs. 2 vs. 3–4), number of active tumors (1 to 5 vs. ≥6), albumin levels (≥3.4 vs. 2.4 to 3.3 vs. <2.4 and primary tumor site (Breast, Kidney or Prostate vs. Other). Risk group stratification was performed by assigning points for adverse prognostic factors resulting in very low, low, intermediate and high risk groups. The median survival was >31.4 months for very low risk patients compared to 14.5 months for low risk, 4.1 months for intermediate risk and 1.2 months for high risk (p<0.001).ConclusionsThese data suggest that a model that considers performance status, extent of disease, primary tumor site and serum albumin represents a simple model to accurately predict survival for patients with stage IV cancer who are potential candidates for radiation therapy.  相似文献   

5.
The retrospective analysis has concerned 323 patients with acute nonlymphocytic leukaemia (ANLL). The comparable patients groups were treated since 1981 according to protocols used by the Polish Acute Leukaemia Group (induction; modified TAD or Adriamycin plus Ara-C, maintenance; rotatingly changed polychemotherapy for 3 years). The prognostic value for achieving complete remission (CR) and survival of 67 pre-treatment factors (42 quantitative and 25 qualitative) was evaluated. The most important 9 parameters were scored according to the prognostic value as follows: age, proportion of blasts in bone marrow, blast count in peripheral blood, morphological subtype, percentage of granulocytes in bone marrow, proportion of blasts with CD-15 antigen, thrombocyte count, spleen/liver enlargement, protein concentration in cerebro-spinal fluid. The scoring system has been elaborated allowing selection of ANLL patients to standard risk group and a high risk group.  相似文献   

6.
Several prognostic factors for patients with myelodysplastic syndromes (MDS) have been identified in previous years. In order to determine prognostic factors characterizing haematopoietic cell kinetics, bone marrow proliferative activity and serum TNF-a levels were measured in 51 cases of MDS. Cell proliferation was evaluated by employing a monoclonal antibody directed against the proliferating cell nuclear antigen (PCNA). The PCNA proliferating index (PCNA PI) and serum TNF-a levels showed significant differences between patients with MDS and normal controls (p<0.0001). PCNA PI and serum TNF-a were significantly higher in the high risk for leukemic transformation FAB subgroups (RAEB, RAEB-t and CMML) in comparison to the low risk group (RA and RARS) (p<0.001). PCNA PI and TNF-a also increased with increasing IPSS score (p<0.05). A positive correlation was noted between TNF-a concentrations and PCNA PI (r:0.36, p<0.008). Univariate analysis using the log-rank test showed that a higher PCNA PI was associated with a significantly shorter survival (p<0.001). We conclude that elevated PCNA PI and TNF-a serum levels are increased in high risk myelodysplastic disease and that a high PCNA PI is predictive of a shorter survival in this group of patients.  相似文献   

7.
During the past few years our understanding of the genetic basis for the myelodysplastic syndromes (MDS) has improved significantly. A few subgroups have been studied in detail and the genetic alterations are now to a great extent revealed. In 5q- syndrome haploinsufficiency of the ribosomal gene RPS14 appears to cooperate with loss of two micro-RNAs miR-145 and miR-146 to induce key features of the disease. Some mutations are specific for certain categories of MDS while others, such as TET2 seem to occur across the various categories. JAK2 mutations are mainly found in patients with myeloproliferative characteristics. The prognostic implications of most of the novel mutations are not yet fully understood, moreover, functional studies are required in order to understand the interplay between the different lesions; how they give rise to the disease and how some may lead to disease evolution including leukemic transformation. An improved understanding of the pathophysiology of MDS may lead to the identification of suitable targets for future drug development.  相似文献   

8.

Background

Whether vexing clinical decision-making dilemmas can be partly addressed by recent advances in genomics is unclear. For example, when to initiate highly active antiretroviral therapy (HAART) during HIV-1 infection remains a clinical dilemma. This decision relies heavily on assessing AIDS risk based on the CD4+ T cell count and plasma viral load. However, the trajectories of these two laboratory markers are influenced, in part, by polymorphisms in CCR5, the major HIV coreceptor, and the gene copy number of CCL3L1, a potent CCR5 ligand and HIV-suppressive chemokine. Therefore, we determined whether accounting for both genetic and laboratory markers provided an improved means of assessing AIDS risk.

Methods and Findings

In a prospective, single-site, ethnically-mixed cohort of 1,132 HIV-positive subjects, we determined the AIDS risk conveyed by the laboratory and genetic markers separately and in combination. Subjects were assigned to a low, moderate or high genetic risk group (GRG) based on variations in CCL3L1 and CCR5. The predictive value of the CCL3L1-CCR5 GRGs, as estimated by likelihood ratios, was equivalent to that of the laboratory markers. GRG status also predicted AIDS development when the laboratory markers conveyed a contrary risk. Additionally, in two separate and large groups of HIV+ subjects from a natural history cohort, the results from additive risk-scoring systems and classification and regression tree (CART) analysis revealed that the laboratory and CCL3L1-CCR5 genetic markers together provided more prognostic information than either marker alone. Furthermore, GRGs independently predicted the time interval from seroconversion to CD4+ cell count thresholds used to guide HAART initiation.

Conclusions

The combination of the laboratory and genetic markers captures a broader spectrum of AIDS risk than either marker alone. By tracking a unique aspect of AIDS risk distinct from that captured by the laboratory parameters, CCL3L1-CCR5 genotypes may have utility in HIV clinical management. These findings illustrate how genomic information might be applied to achieve practical benefits of personalized medicine.  相似文献   

9.
Prognostic models are generally used to predict gastric cancer outcomes. However, no model combining patient-, tumor- and host-related factors has been established to predict outcomes after radical gastrectomy, especially outcomes of patients without nodal involvement. The aim of this study was to develop a prognostic model based on the systemic inflammatory response and clinicopathological factors of resectable gastric cancer and determine whether the model can improve prognostic accuracy in node-negative patients. We reviewed the clinical, laboratory, histopathological and survival data of 1397 patients who underwent radical gastrectomy between 2007 and 2013. Patients were split into development and validation sets of 1123 and 274 patients, respectively. Among all 1397 patients, 545 had node-negative gastric cancer; 440 were included in the development set, 105 were included in the validation set. A prognostic model was constructed from the development set. The scoring system was based on hazard ratios in a Cox proportional hazard model. In the multivariate analysis, age, tumor size, Lauren type, depth of invasion, lymph node metastasis, and the neutrophil—lymphocyte ratio were independent prognostic indicators of overall survival. A prognostic model was then established based on the significant factors. Patients were categorized into five groups according to their scores. The 3-year survival rates for the low- to high-risk groups were 98.9%, 92.8%, 82.4%, 58.4%, and 36.9%, respectively (P < 0.001). The prognostic model clearly discriminated patients with stage pT1-4N0M0 tumor into four risk groups with significant differences in the 3-year survival rates (P < 0.001). Compared with the pathological T stage, the model improved the predictive accuracy of the 3-year survival rate by 5% for node-negative patients. The prognostic scores also stratified the patients with stage pT4aN0M0 tumor into significantly different risk groups (P = 0.004). Furthermore, the predictive value of this model was validated in an independent set of 274 patients. This model, which included the systemic inflammatory markers and clinicopathological factors, is more effective in predicting the prognosis of node-negative gastric cancer than traditional staging systems. Patients in the high-risk group might be good candidates for adjuvant chemotherapy.  相似文献   

10.
Myelodysplasia (MDS) is a heterogeneous disorder characterised by bone marrow failure and progression to acute myeloid leukaemia where the molecular and cellular haematopoietic defects are poorly understood. To gain insight into this the pathogenesis of this condition, we analyzed gene expression profiles of bone marrow CD34+ stem/progenitor cells from patients with MDS at a early stage in the disease and compared them with profiles from CD34+ cells from age-matched controls and patients with non-MDS anaemia. Given the heterogeneity of early MDS, a surprisingly consistent finding was decreased expression of B-cell lineage affiliated genes in MDS patients compared to normal controls and samples with non-MDS anaemia. These findings were then confirmed in the original samples and further samples from a new MDS patient group by Taqman Real Time PCR. Flow cytometry on unfractionated marrow from independent samples also demonstrated reduced B-cell progenitors in MDS patients compared to normal controls. These novel findings suggest a common perturbation in early MDS haematopoiesis. They also provide the rationale for a larger study to evaluate the diagnostic utility of reduced B-cell progenitor number as a diagnostic biomarker of early low risk MDS which can pose a diagnostic challenge.  相似文献   

11.
The identification of human predisposition genes to severe forms of infectious diseases is important for understanding the mechanisms of pathogenesis, as well as for the detection of the risk groups. This will allow one to carry out targeted vaccination and preventive therapy. The most common approaches to the genetic risk estimation include conducting association studies, in which the groups of patients and control individuals are compared using both preliminarily selected candidate genes and using genome-wide analysis. To search for genetic variants predisposed to severe forms of infectious diseases, it is expedient to form a control that consists of patients with clinically proven infections with asymptomatic or mild forms of the disease. The examples of the use of these approaches to identify genetic factors that predispose one to severe forms of infections caused by viruses from the Flaviviridae family are considered in the review. At present, a number of genetic markers associated with predisposition to tick-borne encephalitis, West Nile fever, and Dengue fever have already been detected. These associations must be confirmed in independent samples. Genetic variants, for which the association with spontaneous recovery during infection with hepatitis C virus, patient’s reaction on antiviral drugs, and the development of liver fibrosis was established, were also detected. The gene variants with more pronounced phenotypic effects will probably be found during further studies; they can be used in clinical practice as prognostic markers of the course and outcomes of infection with the Flaviviridae, as well as of the response to treatment.  相似文献   

12.
To assess the relevance of molecular markers it is required to combine clinical and genetic information. For reliable assessment of parameters relevant to diagnostics and therapy large patient collectives must be characterized both with respect to phenotype and genotype. Matching of genetic data like gene expression profiles, molecular genetics and cytogenetics with clinical data like follow-up, morphological findings and diagnoses involves integration of complex databases. In the context of a nationwide leukemia research network in Germany we designed an integrated database covering both genetic and clinical data of patients. The system contains follow-up data and relevant laboratory modalities, i. e. cytomorphology, cytogenetics, molecular genetics, FISH, immunophenotyping and gene expression profiling. So far 13,541 cases from 7,746 patients treated by 1,225 physicians are documented. The data structure consists of up to 888 variables per case. From our experience, integration of clinical and genetic information requires significant efforts - including data protection issues -, but is feasible and improves data quality leading to faster and more reliable research results for the benefit of the patients.  相似文献   

13.
Recent evidence indicates that melanoma comprises distinct types of tumors and suggests that specific morphological features may help predict its clinical behavior. Using a SNP‐array approach, we quantified chromosomal copy number alterations (CNA) across the whole genome in 41 primary melanomas and found a high degree of heterogeneity in their genomic asset. Association analysis correlating the number and relative length of CNA with clinical, morphological, and dermoscopic attributes of melanoma revealed that features of aggressiveness were strongly linked to the overall amount of genomic damage. Furthermore, we observed that melanoma progression and survival were mainly affected by a low number of large chromosome losses and a high number of small gains. We identified the alterations most frequently associated with aggressive melanoma, and by integrating our data with publicly available gene expression profiles, we identified five genes which expression was found to be necessary for melanoma cells proliferation. In conclusion, this work provides new evidence that the phenotypic heterogeneity of melanoma reflects a parallel genetic diversity and lays the basis to define novel strategies for a more precise prognostic stratification of patients.  相似文献   

14.
BackgroundThis study planned to investigate the relationship of dynamic thiol/disulfide homeostasis with the prognosis of myelodysplastic syndrome (MDS).Methods80 patients who had been diagnosed with MDS between 2012 and 2017 and who were older than 18 were included in the study together with 80 healthy control subjects. The MDS diagnosis was confirmed using bone marrow aspiration-biopsy immunostaining. Dynamic thiol/disulfide homeostasis and ischemia-modified albumin (IMA) levels were examined.ResultsThe average IMA (0.71±0.08 vs. 0.67±0.09; p=0.002), median disulfide (18.0 vs. 11.6; p<0.001), median disulfide/native thiol (6 vs. 3; p<0.001), and median disulfide/total thiol (5.4 vs. 2.9; p<0.001) were found higher in the MDS patients compared to control group, and the median hemoglobin, median white blood cell count, median neutrophil count, median lymphocyte count, average native thiol (290.7±48.5 vs. 371.5±103.8; p<0.001), average total thiol (328.2±48.9 vs. 393±105.5; p<0.001), and average native thiol/total thiol (%) (88.3±4.3 vs. 94.2±2.1; p<0.001) were found to below. Risk factors such as collagen tissue disease (HR:9.17; p=0.005), MDS-EB-1 (HR:10.14; p=0.032), MDS-EB-2 (HR:18.2; p=0.043), and disulfide/native thiol (HR:1.17; p=0.023) were found as the independent predictors anticipating progression to acute myeloid leukemia. In the Cox regression model, risk factors such as age (HR:1.05; p=0.002), MDS-EB-1 (HR:12.58; p<0.001), MDS-EB-2 (HR:5.75; p=0.033), disulfide/native thiol (HR:1.14; p=0.040), and hemoglobin (HR:0.64; p=0.007) were found as predictors anticipating for mortality.ConclusionsWe can argue that dynamic thiol/disulfide homeostasis could have significant effects on both the etiopathogenesis and the survival of patients with MDS, and it could be included in new prognostic scoring systems.  相似文献   

15.

Background

Increased rates for failure in leishmaniasis antimony treatment have been recently recognized worldwide. Although several risk factors have been identified there is no clinical score to predict antimony therapy failure of cutaneous leishmaniasis.

Methods

A case control study was conducted in Peru from 2001 to 2004. 171 patients were treated with pentavalent antimony and followed up to at least 6 months to determine cure or failure. Only patients with ulcerative cutaneous leishmaniasis (N = 87) were considered for data analysis. Epidemiological, demographical, clinical and laboratory data were analyzed to identify risk factors for treatment failure. Two prognostic scores for antimonial treatment failure were tested for sensitivity and specificity to predict antimony therapy failure by comparison with treatment outcome.

Results

Among 87 antimony-treated patients, 18 (21%) failed the treatment and 69 (79%) were cured. A novel risk factor for treatment failure was identified: presence of concomitant distant lesions. Patients presenting concomitant-distant lesions showed a 30.5-fold increase in the risk of treatment failure compared to other patients. The best prognostic score for antimonial treatment failure showed a sensitivity of 77.78% and specificity of 95.52% to predict antimony therapy failure.

Conclusions

A prognostic score including a novel risk factor was able to predict antimonial treatment failure in cutaneous leishmaniasis with high specificity and sensitivity. This prognostic score presents practical advantages as it relies on clinical and epidemiological characteristics, easily obtained by physicians or health workers, and makes it a promising clinical tool that needs to be validated before their use for developing countries.  相似文献   

16.
The increasing life expectancy and the increasingly advanced age of parenthood due to socio-economic conditions in developed countries, combined with progress in medically-assisted procreation techniques account for the recent interest in the fertility of ageing men. Hormonal changes (primary testicular deficiency, decreased amplitude of hypothalamic GnRH secretion peaks), morphological and histological testicular changes (arteriolar sclerosis, Leydig cell and Sertoli cell degeneration, rarefaction of germ cells, thickening of the testicular tunica albuginea) related to physiological ageing are relatively well documented. The repercussions of these physiological changes on the quality of the semen of ageing men is difficult to clearly establish because of the limited data available and the marked interindividual variability of semen parameters. Globally, the quality of semen gradually decreases with age, although a cut-off age cannot be defined. The alterations observed essentially concern the volume of the ejaculate, and the mobility and morphology of spermatozoa. The sperm count appears to be less markedly affected. However, all of the other pathological and psychosocial factors frequently observed in ageing men must be taken into account in the interpretation of the data (changes of the bladder neck and genital tract, chronic diseases, drug treatments, smoking, decreased frequency of sexual intercourse, partner’s age). Further comparative studies, including a larger number of elderly patients in clearly defined age-groups, with populations matched for other risk factors for alteration of semen quality, are necessary. Overall, a review of the literature does not reveal any specific prognostic criteria for age-related fertility. Regardless of the semen characteristics of an ageing man desiring possible paternity, a complete clinical and andrological assessment must be performed.  相似文献   

17.
《IRBM》2023,44(3):100748
ObjectivesEsophageal cancer is a high occult malignant tumor. Even with good diagnosis and treatment, the 5-year survival rate of esophageal cancer patients is still less than 30%. Considering the influence of clinical characteristics on postoperative esophageal cancer patients, the construction of a neural network model will help improve the poor prognosis of patients in the five years.Material and methodsIn this study, genetic algorithm optimized deep neural network is exploited to the clinical dataset of esophageal cancer. The independent prognostic factors are screened by Relief algorithm and Cox proportional risk regression. FTD prognostic staging system is established to assess the risk level of esophageal cancer patients.ResultsFTD staging system and independent prognostic factors are integrated into the genetic algorithm optimized deep neural network. The Area Under Curve (AUC) of FTD staging system is 0.802. FTD staging system is verified by the Kaplan-Meier survival curve, and the median survival time is divided for different risk grades. The FTD staging system is superior to the TNM stages in the prognosis effect. The AUC of deep neural network optimized by genetic algorithm is 0.91.ConclusionThe deep neural network optimized by genetic algorithm has good performance in predicting the 5-year survival status of esophageal cancer patients. The FTD staging system has a significant prognostic effect. The FTD staging system and genetic algorithm optimized deep neural network can be successfully availed in clinical diagnosis and treatment.  相似文献   

18.

Background

Phenotypes are variable within species, with high phenotypic variation in the fitness and cell morphology of natural yeast strains due to genetic variation. A gene deletion collection of yeast laboratory strains also contains phenotypic variations, demonstrating the involvement of each gene and its specific function. However, to date, no study has compared the phenotypic variations between natural strains and gene deletion mutants in yeast.

Results

The morphological variance was compared between 110 most distinct gene deletion strains and 36 typical natural yeast strains using a generalized linear model. The gene deletion strains had higher morphological variance than the natural strains. Thirty-six gene deletion mutants conferred significant morphological changes beyond that of the natural strains, revealing the importance of the genes with high genetic interaction and specific cellular functions for species conservation.

Conclusion

Based on the morphological analysis, we discovered gene deletion mutants whose morphologies were not seen in nature. Our multivariate approach to the morphological diversity provided a new insight into the evolution and species conservation of yeast.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-932) contains supplementary material, which is available to authorized users.  相似文献   

19.
Antibodies to citrullinated proteins (anti-cyclic-citrullinated peptide [anti-CCP] antibodies) are highly specific for rheumatoid arthritis (RA) and precede the onset of disease symptoms, indicating a pathogenetic role for these antibodies in RA. We recently showed that distinct genetic risk factors are associated with either anti-CCP-positive disease or anti-CCP-negative disease. These data are important as they indicate that distinct pathogenic mechanisms are underlying anti-CCP-positive disease or anti-CCP-negative disease. Likewise, these observations raise the question of whether anti-CCP-positive RA and anti-CCP-negative RA are clinically different disease entities. We therefore investigated whether RA patients with anti-CCP antibodies have a different clinical presentation and disease course compared with patients without these autoantibodies. In a cohort of 454 incident patients with RA, 228 patients were anti-CCP-positive and 226 patients were anti-CCP-negative. The early symptoms, tender and swollen joint count, and C-reactive protein level at inclusion, as well as the swollen joint count and radiological destruction during 4 years of follow-up, were compared for the two groups. There were no differences in morning stiffness, type, location and distribution of early symptoms, patients' rated disease activity and C-reactive protein at inclusion between RA patients with and without anti-CCP antibodies. The mean tender and swollen joint count for the different joints at inclusion was similar. At follow-up, patients with anti-CCP antibodies had more swollen joints and more severe radiological destruction. Nevertheless, the distribution of affected joints, for swelling, bone erosions and joint space narrowing, was similar. In conclusion, the phenotype of RA patients with or without anti-CCP antibodies is similar with respect to clinical presentation but differs with respect to disease course.  相似文献   

20.
Cardiovascular disease (CVD) is closely associated with familial predisposition. The aim of the present study was to investigate predisposing risk factors in the family of a young patient who underwent coronary artery bypass graft surgery due to CVD. The father and uncle of the patient died at an early age due to myocardial infarction. Various stages of CVD were identified in both of the patient’s brothers (28 and 32 years of age). Biochemical tests (fasting blood glucose, lipid profile, urea, creatinine and liver enzymes) and a complete blood count (haemoglobin, haematocrit, white blood cell count, and platelet count) were performed. Physiological coagulation inhibitory factors (protein C, protein S, and antithrombin III), prothrombotic genetic risk factors (factor V Leiden, plasminogen activator inhibitor-1, methylenetetrahydrofolate reductase A1C and C6T, angiotensin-converting enzyme, β-fibrinogen, glycoprotein IIIa and factor XIII) and homocysteine levels were evaluated in all cases. Defects were observed in many genetic factors and in the systems regulated by these factors. The results were compatible with those reported in the literature. In conclusion, it is possible to determine a specific family history in young adults with CVD. From this perspective, the emergence of more serious CVD may be prevented by providing disease-related information to the other family members and implementing preventive measures.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号