Dynamic radiomics based on contrast-enhanced MRI for predicting microvascular invasion in hepatocellular carcinoma.

OBJECTIVE: To exploit the improved prediction performance based on dynamic contrast-enhanced (DCE) MRI by using dynamic radiomics for microvascular invasion (MVI) in hepatocellular carcinoma (HCC). METHODS: We retrospectively included 175 and 75 HCC patients who underwent preoperative DCE-MRI from September 2019 to August 2022 in institution 1 (development cohort) and institution 2 (validation cohort), respectively. Static radiomics features were extracted from the mask, arterial, portal venous, and equilibrium phase images and used to construct dynamic features. The static, dynamic, and dynamic-static radiomics (SR, DR, and DSR) signatures were separately constructed based on the feature selection method of LASSO and classification algorithm of logistic regression. The receiver operating characteristic (ROC) curves and the area under the curve (AUC) were plotted to evaluate and compare the predictive performance of each signature. RESULTS: In the three radiomics signatures, the DSR signature performed the best. The AUCs of the SR, DR, and DSR signatures in the training set were 0.750, 0.751 and 0.805, respectively, while in the external validation set, the corresponding AUCs were 0.706, 0756 and 0.777. The DSR signature showed significant improvement over the SR signature in predicting MVI status (training cohort: P = 0.019; validation cohort: P = 0.044). After external validation, the AUC value of the SR signature decreased from 0.750 to 0.706, while the AUC value of the DR signature did not show a decline (AUCs: 0.756 vs. 0.751). CONCLUSIONS: The dynamic radiomics had an improved effect on the MVI prediction in HCC, compared with the static DCE MRI-based radiomics models.

Novel PATL2 variants cause female infertility with oocyte maturation defect.

PURPOSE: Oocyte maturation defect (OOMD) is a rare cause of in vitro fertilization failure characterized by the production of immature oocytes. Compound heterozygous or homozygous PATL2 mutations have been associated with oocyte arrest at the germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) stages, as well as morphological changes. METHODS: In this study, we recruited three OOMD cases and conducted a comprehensive multiplatform laboratory investigation. RESULTS: Whole exome sequence (WES) revealed four diagnostic variants in PATL2, nonsense mutation c.709C > T (p.R237*) and frameshift mutation c.1486_1487delinsT (p.A496Sfs*4) were novel mutations that have not been reported previously. Furthermore, the pathogenicity of these variants was predicted using in silico analysis, which indicated detrimental effects. Molecular dynamic analysis suggested that the A496S variant disrupted the hydrophobic segment, leading to structural changes that affected the overall protein folding and stability. Additionally, biochemical and molecular experiments were conducted on cells transfected with wild-type (WT) or mutant PATL2 (p.R237* and p.A496Sfs*4) plasmid vectors. CONCLUSIONS: The results demonstrated that PATL2A496Sfs*4 and PATL2R237* had impacts on protein size and expression level. Interestingly, expression levels of specific genes involved in oocyte maturation and early embryonic development were found to be simultaneously deregulated. The findings in our study expand the variation spectrum of the PATL2 gene, provide solid evidence for counseling on future pregnancies in affected families, strongly support the application of in the diagnosis of OOMD, and contribute to the understanding of PATL2 function.

Development and external validation of a multiparametric MRI-based radiomics model for preoperative prediction of microsatellite instability status in rectal cancer: a retrospective multicenter study.

OBJECTIVES: To establish and validate a radiomics model based on multiparametric magnetic resonance imaging (MRI), and to predict microsatellite instability (MSI) status in rectal cancer patients. METHODS: A total of 199 patients with pathologically confirmed rectal cancer were included. The MSI status was confirmed by immunohistochemistry (IHC) staining. Clinical factors and laboratory data associated with MSI status were analyzed. The imaging data of 100 patients from one of the hospitals were used as the training set. The remaining 99 patients from the other two hospitals were used as the external validation set. The regions of interest (ROIs) were delineated from T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and contrast-enhanced T1WI (CE-T1WI) sequence to extract the radiomics features. The Tree-based approach was used for feature selection. The models were constructed based on the four single sequences and a combination of the four sequences using the random forest (RF) algorithm. The external validation set was used to verify the generalization ability of each model. The receiver operating characteristic (ROC) curves and the area under the curve (AUC) were plotted to evaluate and compare the predictive performance of each model. RESULTS: In the four single-series models, the CE-T1WI model performed the best. The AUCs of the T1WI, T2WI, DWI, and CE-T1WI prediction models in the training set were 0.74, 0.71, 0.71, and 0.78, respectively, while in the external validation set, the corresponding AUCs were 0.67, 0.66, 0.70, and 0.77. The prediction and generalization performance of the combined model of multi-sequences was comparable to that of the CE-T1WI model and it was better than that of the remaining three single-series models, with AUC values of 0.78 and 0.78 in the training and validation sets, respectively. CONCLUSION: The established radiomics models based on CE-T1WI or multiparametric MRI have similar predictive performance. They have the potential to predict MSI status in rectal cancer patients. KEY POINTS: • A radiomics model for the prediction of MSI status in patients with rectal cancer was established and validated using external validation. • The models based on CE-T1WI or multiparametric MRI have better predictive performance than those based on single unenhanced sequence images. • The radiomics model has the potential to suggest MSI status in rectal cancer patients; however, it is not yet a substitute for histological confirmation.

Quantitative Relaxometry Assessment of Brain Microstructural Abnormality of Preschool Children With Autism Spectrum Disorder With Synthetic Magnetic Resonance Imaging.

OBJECTIVE: This study aimed to perform an assessment of brain microstructure in children with autism aged 2 to 5 years using relaxation times acquired by synthetic magnetic resonance imaging. MATERIALS AND METHODS: Thirty-four children with autism spectrum disorder (ASD) (ASD group) and 17 children with global developmental delay (GDD) (GDD group) were enrolled, and synthetic magnetic resonance imaging was performed to obtain T1 and T2 relaxation times. The differences in brain relaxation times between the 2 groups of children were compared, and the correlation between significantly changed T1/T2 and clinical neuropsychological scores in the ASD group was analyzed. RESULTS: Compared with the GDD group, shortened T1 relaxation times in the ASD group were distributed in the genu of corpus callosum (GCC) ( P = 0.003), splenium of corpus callosum ( P = 0.002), and right thalamus (TH) ( P = 0.014), whereas shortened T2 relaxation times in the ASD group were distributed in GCC ( P = 0.011), left parietal white matter ( P = 0.035), and bilateral TH (right, P = 0.014; left, P = 0.016). In the ASD group, the T2 of the left parietal white matter is positively correlated with gross motor (developmental quotient [DQ] 2) and personal-social behavior (DQ5), respectively ( r = 0.377, P = 0.028; r = 0.392, P = 0.022); the T2 of the GCC was positively correlated with DQ5 ( r = 0.404, P = 0.018); and the T2 of the left TH is positively correlated with DQ2 and DQ5, respectively ( r = 0.433, P = 0.009; r = 0.377, P = 0.028). All significantly changed relaxation values were not significantly correlated with Childhood Autism Rating Scale scores. CONCLUSIONS: The shortened relaxometry times in the brain of children with ASD may be associated with the increased myelin content and decreased water content in the brain of children with ASD in comparison with GDD, contributing the understanding of the pathophysiology of ASD. Therefore, the T1 and T2 relaxometry may be used as promising imaging markers for ASD diagnosis.

Complete chloroplast genome of Gentianopsis barbata and comparative analysis with related species from Gentianaceae.

Gentianopsis barbata is an essential medicinal plant in China with high ornamental and medicinal values. Unfortunately, the study of the chloroplast genome of this plant still has a gap. This study sequenced and characterized the complete chloroplast genome of G. barbata. The complete chloroplast genome of G. barbata is a typical circular structure of 151 123 bp. It consists of a large single-copy region (82 690 bp) and a small single-copy region (17 887 bp) separated by a pair of inverted repeats (25 273 bp), which covers 78 protein-coding genes, 30 tRNAs, and 4 rRNAs. The long repeat sequence analysis showed that the P-type (palindromic) sequences were the major long repeat sequences. Thirty-seven simple sequence repeats were identified, most of which were single nucleotides. The Bayesian inference tree, maximum likelihood tree, and neighbor-joining tree suggested that G. barbata is grouped with Gentianopsis grandis and Gentianopsis paludosa. The divergence time analysis showed that G. barbata diverged at 1.243 Mya. Comparative analysis of chloroplast genomes can reveal interspecific diversity, and regions with high variation can be used to develop molecular markers applicable to various research areas. Our results provide a new insight into plastome evolution and a valuable resource for further studies on G. barbata.

Factors associated with medical students' self-regulated learning and its relationship with clinical performance: a cross-sectional study.

BACKGROUND: The importance of self-regulated learning (SRL) has been broadly recognised by medical education institutions and medical professionals. Self-regulated learning, which is a context-specific process, is affected by personal, contextual and social factors. Although many studies on exploring the factors that influenced SRL and the relationship of between SRL and clinical achievement levels have been carried out in western countries, little is known about the factors associated with self-regulated learning and its relationship with clinical performance among medical students in China. METHODS: A cross-sectional online survey was distributed to 3rd year clinical medicine students who were in the clinical clerkship stage in a medical college in Wuhan. We used Self-regulated Learning Scale for Undergraduates (SLSU) to measure the self-regulated learning of students and Objective Structured Clinical Examination (OSCE) in the national proficiency test to assess the clinical performance of students. The participation rate was 73.95% (193 students). An independent t-test and analysis of variance were used to analyse the factors associated with self-regulated learning. The relationship between self-regulated learning and clinical performance was analysed with multilinear regression analysis. RESULTS: Univariate analysis showed that having a clear career planning and a professional idol, providing full-time teaching clinical teachers in the clerkship department and seeking the help of the surrounding classmates and the guidance of teachers or senior students were significant predictors of self-regulated learning. Multilinear regression analysis has revealed a positive relationship among extrinsic goals (partial r = 0.171), clinical clerkship evaluation (partial r = 0.197) and clinical performance (F = 4.070, p = 0.004). CONCLUSIONS: Motivation-related personal and social factors related to clinical context could promote the SRL level of medical students in China. Extrinsic goals and clinical clerkship evaluation could facilitate students' clinical achievements on clinical skills. External support, such as clinical clerkship management, might improve clinical performance on clinical skills in clinical clerkship context.

Comprehensive strategy improves the genetic diagnosis of different polycystic kidney diseases.

Polycystic kidney disease (PKD) is known to occur in three main forms, namely autosomal dominant PKD (ADPKD), autosomal recessive PKD (ARPKD) and syndromic PKD (SPKD), based on the clinical manifestations and genetic causes, which are diagnosable from the embryo stage to the later stages of life. Selection of the genetic test for the individuals with diagnostic imaging reports of cystic kidneys without a family history of the disease continues to be a challenge in clinical practice. With the objective of maintaining a limit on the time and medical cost of the procedure, a practical strategy for genotyping and targeted validation to resolve cystogene variations was developed in our clinical laboratory, which combined the techniques of whole-exome sequencing (WES), Long-range PCR (LR-PCR), Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) to work in a stepwise approach. In this context, twenty-six families with renal polycystic disorders were enrolled in the present study. Thirty-two variants involving four ciliary genes (PKD1, PKHD1, TMEM67 and TMEM107) were identified and verified in 23 families (88.5%, 23/26), which expanded the variant spectrum by 16 novel variants. Pathogenic variations in five foetuses of six families diagnosed with PKD were identified using prenatal ultrasound imaging. Constitutional biallelic and digenic variations constituted the pathogenic patterns in these foetuses. The preliminary clinical data highlighted that the WES + LR PCR-based workflow followed in the present study is efficient in detecting divergent variations in PKD. The biallelic and digenic mutations were revealed as the main pathogenic patterns in the foetuses with PKD.

Risk stratification of thymic epithelial tumors by using a nomogram combined with radiomic features and TNM staging.

OBJECTIVES: To construct and validate a nomogram model that integrated the CT radiomic features and the TNM staging for risk stratification of thymic epithelial tumors (TETs). METHODS: A total of 136 patients with pathology-confirmed TETs who underwent CT examination were collected from two institutions. According to the WHO pathological classification criteria, patients were classified into low-risk and high-risk groups. The TNM staging was determined in terms of the 8th edition AJCC/UICC staging criteria. LASSO regression was performed to extract the optimal features correlated to risk stratification among the 704 radiomic features calculated. A nomogram model was constructed by combining the Radscore and the TNM staging. The clinical performance was evaluated by ROC analysis, calibration curve, and decision curve analysis (DCA). The Kaplan-Meier (KM) analysis was employed for survival analysis. RESULTS: Five optimal features identified by LASSO regression were employed to calculate the Radscore correlated to risk stratification. The nomogram model showed a better performance in both training cohort (AUC = 0.84, 95%CI 0.75-0.91) and external validation cohort (AUC = 0.79, 95%CI 0.69-0.88). The calibration curve and DCA analysis indicated a better accuracy of the nomogram model for risk stratification than either Radscore or the TNM staging alone. The KM analysis showed a significant difference between the two groups stratified by the nomogram model (p = 0.02). CONCLUSIONS: A nomogram model that integrated the radiomic signatures and the TNM staging could serve as a reliable model of risk stratification in predicting the prognosis of patients with TETs. KEY POINTS: • The radiomic features could be associated with the TET pathophysiology. • TNM staging and Radscore could independently stratify the risk of TETs. • The nomogram model is more objective and more comprehensive than previous methods.

Effect of COVID-19 outbreak on the treatment time of patients with acute ST-segment elevation myocardial infarction.

OBJECTIVE: To explore the effect of COVID-19 outbreak on the treatment time of patients with ST-segment elevation myocardial infarction (STEMI) in Hangzhou, China. METHODS: We retrospectively reviewed the data of STEMI patients admitted to the Hangzhou Chest Pain Center (CPC) during a COVID-19 epidemic period in 2020 (24 cases) and the same period in 2019 (29 cases). General characteristics of the patients were recorded, analyzed, and compared. Moreover, we compared the groups for the time from symptom onset to the first medical contact (SO-to-FMC), time from first medical contact to balloon expansion (FMC-to-B), time from hospital door entry to first balloon expansion (D-to-B), and catheter room activation time. The groups were also compared for postoperative cardiac color Doppler ultrasonographic left ventricular ejection fraction (LVEF),the incidence of major adverse cardiovascular and cerebrovascular events (MACCE),Kaplan-Meier survival curves during the 28 days after the operation. RESULTS: The times of SO-to-FMC, D-to-B, and catheter room activation in the 2020 group were significantly longer than those in the 2019 group (P < 0.05). The cumulative mortality after the surgery in the 2020 group was significantly higher than the 2019 group (P < 0.05). CONCLUSION: The pre-hospital and in-hospital treatment times of STEMI patients during the COVID-19 epidemic were longer than those before the epidemic. Cumulative mortality was showed in Kaplan-Meier survival curves after the surgery in the 2020 group was significantly different higher than the 2019 group during the 28 days.The diagnosis and treatment process of STEMI patients during an epidemic should be optimized to improve their prognosis.

Analysis of terpenoid biosynthesis pathways in German chamomile (Matricaria recutita) and Roman chamomile (Chamaemelum nobile) based on co-expression networks.

German chamomile and Roman chamomile are the two most widely known chamomile species due to the medicinal properties of volatile compounds from their flowers. We determined the volatile compound content of different organs of these two chamomiles, and found that main volatile compounds in German chamomile were terpenoids and those in Roman chamomile were esters. Furthermore, 24 tissues from two chamomiles were sequenced and analyzed by gene co-expression network. The results showed higher terpene synthase expression levels and more modules correlated with sesquiterpenoids in German chamomile, which may explain its high sesquiterpenoid content. In both chamomiles, unigenes in volatile compound-correlated modules were significantly enriched in pathways related to plant-pathogen interactions and circadian rhythm, demonstrating that volatile compounds of chamomiles are influenced by these factors. There were ten times more unigenes related to plant-pathogen interactions in German chamomile than in Roman chamomile, which indicates German chamomile has higher resistance to pathogens.

A comparative-descriptive analysis of clinical characteristics in 2019-coronavirus-infected children and adults.

Acute respiratory disease caused by 2019 novel coronavirus (2019-nCoV) has rapidly spread throughout China. Children and adults show a different clinical course. The purpose of the current study is to comparatively analyze the clinical characteristics of 2019-nCoV infection in children and adults and to explore the possible causes for the discrepancies present. The medical records of 25 adults and 7 children confirmed cases of 2019-2019-nCoV acute respiratory diseases were reviewed retrospectively. All children were family clusters. The total adult patients were differentiated into the local residents of Wuhan, a history of travel to Wuhan and direct contact with people from Wuhan. The numbers were 14 (56%), 10 (40%), and 1 (4%), respectively. The median incubation period of children and adults was 5 days (ranged, 3-12 days) and 4 days (ranged, 2-12 days), respectively. Diarrhoea and/or vomiting (57.1%) were demic by World Health Organiza more common in children, whereas for adults it was myalgia or fatigue (52%). On admission, the percentage of children having pneumonia (5%, 71.4%) was roughly the same as adults (20%, 80%). A total of 20% of adults had leucopoenia, but leukocytosis was more frequently in children (28.6%, P=.014). A higher number of children had elevated creatine kinase isoenzyme (57.1% vs 4%, P=.004). Antiviral therapy was given to all adult patients but to none of the children. In summary, knowledge of these differences between children and adults will not only be helpful for the clinical diagnosis of 2019-nCoV disease, but also for a future discussion on age-specific coronavirus infection.

[Cytogenetic and molecular analysis of a case of Prader-Willi syndrome].

OBJECTIVE: To investigate the significance of cytogenetic and molecular genetic diagnosis of a special type of secondary sexual dysplasia and the applicability of various methods for its detection. METHODS: Using karyotype analysis, array comparative genomic hybridization (aCGH), multiplex ligation-dependent probe amplification (MLPA) and methylation-specific PCR (MS-PCR), we diagnosed and differentially diagnosed a case of secondary sexual dysplasia. RESULTS: Abnormalities were not found in the karyotype analysis or the SRY and AZF gene detection, nor chromosomal duplication and deletion in the initial SurePrint G3 Human CGH Array Kit8×60K.SurePrint G3 unrestricteda CGH ISCA v2,88×60K, however, identified a 68.9 kb deletion of chromosome 15 (hg19:25190737-25259677). MLPA revealed the deletion of exon 3 of the SNRPN gene. MS-PCR showed a significant decrease in the paternal fragment signals, but no difference in the maternal fragment signals between the sample from the patient and that from the control. CONCLUSIONS: The patient was confirmed with Prader-Willi syndrome by various methods of detection.

Design, synthesis and biological evaluation of 3,5-dimethylisoxazole and pyridone derivatives as BRD4 inhibitors.

Bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extra-terminal (BET) family, has been recognized as an attractive candidate target for the treatment targeting gene transcription in several types of cancers. In this study, two types of novel compounds were designed, synthesized and evaluated as BRD4 inhibitors. Therein, pyridone derivatives were more effective against BRD4 protein and human leukemia cell lines MV4-11. Among them, compounds 11d, 11e and 11f were the most potential ones with IC50 values of 0.55 µM, 0.86 µM and 0.80 µM against BRD4, and exhibited remarkable antiproliferative activities against MV4-11 cells with IC50 values of 0.19 µM, 0.32 µM and 0.12 µM, respectively. Moreover, in western blot assay, compound 11e induced down-regulation of C-Myc, which is a significant downstream gene of BRD4. Cell cycle analysis assay also showed that compound 11e could block MV4-11 cells at G0/G1 phase. Taken together, our results suggested that compound 11e and its derivatives were a class of novel structural potential BRD4 inhibitors and could serve as lead compounds for further exploration.

Quantitative parameters of CT texture analysis as potential markersfor early prediction of spontaneous intracranial hemorrhage enlargement.

OBJECTIVE: To objectively quantify intracranial hematoma (ICH) enlargement by analysing the image texture of head CT scans and to provide objective and quantitative imaging parameters for predicting early hematoma enlargement. METHODS: We retrospectively studied 108 ICH patients with baseline non-contrast computed tomography (NCCT) and 24-h follow-up CT available. Image data were assessed by a chief radiologist and a resident radiologist. Consistency analysis between observers was tested. The patients were divided into training set (75%) and validation set (25%) by stratified sampling. Patients in the training set were dichotomized according to 24-h hematoma expansion ≥ 33%. Using the Laplacian of Gaussian bandpass filter, we chose different anatomical spatial domains ranging from fine texture to coarse texture to obtain a series of derived parameters (mean grayscale intensity, variance, uniformity) in order to quantify and evaluate all data. The parameters were externally validated on validation set. RESULTS: Significant differences were found between the two groups of patients within variance at V1.0 and in uniformity at U1.0, U1.8 and U2.5. The intraclass correlation coefficients for the texture parameters were between 0.67 and 0.99. The area under the ROC curve between the two groups of ICH cases was between 0.77 and 0.92. The accuracy of validation set by CTTA was 0.59-0.85. CONCLUSION: NCCT texture analysis can objectively quantify the heterogeneity of ICH and independently predict early hematoma enlargement. KEY POINTS: • Heterogeneity is helpful in predicting ICH enlargement. • CTTA could play an important role in predicting early ICH enlargement. • After filtering, fine texture had the best diagnostic performance. • The histogram-based uniformity parameters can independently predict ICH enlargement. • CTTA is more objective, more comprehensive, more independently operable, than previous methods.

Research Advances in CKLFSF-like MARVEL Transmembrane Domain Containing Member 3.

CKLF-like MARVEL transmembrane domain containing member/chemokine-like factor super family member (CKLFSF/CMTM) is a novel tumor suppressor gene. CMTM3 is broadly expressed in normal human tissues and evolutionary conserved,especially in testis,spleen,and some cells of peripheral blood mononuclear cells. However,its expression is undetectable or down-regulated in most carcinoma cell lines and tissues. Restoration of CMTM3 may inhibit the proliferation,migration,and invasion of carcinoma cells. Although the exact mechanism of its anti-tumor activity remains unclear,CKLFSF3/CMTM3 is closely connected with immune system and associated with sex during tumorigenesis. The study advances of CKLFSF3/CMTM3 are elaborated in this review as CMTM3 may be a new target in the gene therapies for tumors,especially genitourinary tumors,while further studies on CMTM3 and its anti-tumor mechanisms are warranted.

[Studies on flavonoids from Cirsium setosum].

To investigate the chemical constituents of ethyl acetate from Cirsium setosum, fifteen flavonoids were obtained by column chromatography on silica gel, MCI, Sephadex LH-20, and preparative HPLC. Their structures were identified as 4',5,6-trihydroxy-7-methoxyflavone(1), 4',5-dihydroxy-7,8-dimethoxyflavone(2), sorbifolin-6-O-ß-glucopyranoside(3), kaempferol-7-O-α-L-rhamnoside(4), kaempferol(5), quercetin-3-O-ß-D-glucosyl-7-O-α-L-rhamnoside(6), myricetin(7), myricetin-3-O-ß-D-glucoside(8), 5,7- dihydroxy -3',4'- dimethoxyflavone(9), 3',4',5- trihydroxy-3,7-dimethoxyflavone(10), 3',3,4',5-tetrahydroxy-7-methoxyflavone(11), 3'-hydroxy-4',5,7-trimethoxyflavone(12), 7-hydroxy-3',4',5-trimethoxyflavone(13), 4',5-dihydroxy-2',3',7,8-tetramethoxylflavone(14), and 5-hydroxy-2',3',7,8-tetramethoxylflavone(15) by spectroscopic data analysis. All compounds were isolated from this plant for the first time.Compounds(1-15) were evaluated for their hypoglycemic activities by PTP1B enzyme model. Among them, compounds 2, 12, and 14 showed significant PTP1B inhibitory activities with IC50 values of 2.54, 1.85, 2.11 µmol•L⁻¹, respectively.

Influencing factors of mental health of medical students in China.

This study investigated the mental health status of medical students in China, and analyzed the influencing factors in order to provide evidence for mental health education for medical students. A stratified cluster sampling method was used to recruit medical students from Huazhong University of Science and Technology, China. The questionnaire survey on general information and Symptom Checklist 90 (SCL-90) were used for investigation and analysis. The results showed among the 1137 valid questionnaires, 278 (24.45%) participants had SCL-90 score ≥ 160. The top three mental problems of medical students were obsessive-compulsive disorder, interpersonal sensitivity and depression in terms of the factor score ≥ 2.5 and the number of participants who reflected on the diseases. The third-year medical students had the worst mental health status, and fifth-year medical students had the best mental health status. Students from rural area had more psychological problems than those from urban area; furthermore, students with high professional satisfaction, those who were the single child of the family, non-poor students, and those whose parents had high education level had better mental health status. It was concluded that the mental health of medical students is not optimistic in China. Medical students have some mental health problems of different degrees. Factors that influence the mental health of medical students include academic pressure, professional satisfaction level and family environment.

Factors influencing the utilization of postpartum visits among rural women in China.

Postpartum visits (PPVs) are still underutilized in rural China, and identification of factors that influence PPV use is important in ensuring the utilization of maternal health services and for wellbeing of women. A cross-section study was undertaken to collect related data from 347 rural women interviewed six weeks or more after delivery, and an ANOVA was performed to find whether there were significant differences in the number of PPVs among different rural areas in China. According to Andersen's socio-behavioral model of health service use, factors were divided into equitable and inequitable ones. Chi-squared test, univariate and multiple analyses were used to determine the equity of PPV use by identifying factors that were most strongly associated with the use of a PPV. The results showed that 20.2% of the respondents (n=70) did not receive any PPVs, and 62.5% (n=173) of those who had PPVs (n=277) did not receive standard PPVs (referring to at least 3 visits). There was no significant difference among different rural areas in terms of the number of PPVs (F=1.514, P=0.211). Multiple regression analyses revealed that enabling factors such as compensation for delivery expense [OR (95% CI)=2.825 (1.331, 5.995)], village type [OR (95% CI)=1.802 (1.021, 3.182)] and service quality [OR (95% CI)=1.847 (1.074, 3.176)] were strongly associated with PPV use. Both enabling factors such as home visits [OR (95% CI)=1.855 (1.085, 3.174)], service quality [OR (95% CI)=1.993 (1.155, 3.439)] and need factors such as low birth weight [OR (95% CI)=4.424 (1.482, 13.203)] were significantly associated with standard PPV use. Our results suggested that the equitable access to PPVs has been considerably improved in rural areas in China. The associations between inequitable factors and PPV use warrant further exploration, and policies aimed at improving quality and patterns of service supply are needed in order to ensure a full equitable access to maternal health services.