Intelligent gold nanocluster for effective treatment of malignant tumor via tumor-specific photothermal-chemodynamic therapy with AIE guidance.

Precise and efficient therapy of malignant tumors is always a challenge. Herein, gold nanoclusters co-modified by aggregation-induced-emission (AIE) molecules, copper ion chelator (acylthiourea) and tumor-targeting agent (folic acid) were fabricated to perform AIE-guided and tumor-specific synergistic therapy with great spatio-temporal controllability for the targeted elimination and metastasis inhibition of malignant tumors. During therapy, the functional gold nanoclusters (AuNTF) would rapidly accumulate in the tumor tissue due to the enhanced permeability and retention effect as well as folic acid-mediated tumor targeting, which was followed by endocytosis by tumor cells. After that, the overexpressed copper ions in the tumor cells would trigger the aggregation of these intracellular AuNTF via a chelation process that not only generated the photothermal agent in situ to perform the tumor-specific photothermal therapy damaging the primary tumor, but also led to the copper deficiency of tumor cells to inhibit its metastasis. Moreover, the copper ions were reduced to cuprous ions along with the chelation, which further catalysed the excess H2O2 in the tumor cells to produce cytotoxic reactive oxygen species, resulting in additional chemodynamic therapy for enhanced antitumor efficiency. The aggregation of AuNTF also activated the AIE molecules to present fluorescence, which not only imaged the therapeutic area for real-time monitoring of this tumor-specific synergistic therapy, but also allowed us to perform near-infrared radiation at the correct time point and location to achieve optimal photothermal therapy. Both in vitro and in vivo results revealed the strong tumor elimination, effective metastasis inhibition and high survival rate of tumor-bearing mice after treatment using the AuNTF nanoclusters, indicating that this AIE-guided and tumor-specific synergistic strategy could offer a promising approach for tumor therapy.

Intelligent nanoreactor coupling tumor microenvironment manipulation and H2O2-dependent photothermal-chemodynamic therapy for accurate treatment of primary and metastatic tumors.

Tumor microenvironment (TME), as the "soil" of tumor growth and metastasis, exhibits significant differences from normal physiological conditions. However, how to manipulate the distinctions to achieve the accurate therapy of primary and metastatic tumors is still a challenge. Herein, an innovative nanoreactor (AH@MBTF) is developed to utilize the apparent differences (copper concentration and H2O2 level) between tumor cells and normal cells to eliminate primary tumor based on H2O2-dependent photothermal-chemodynamic therapy and suppress metastatic tumor through copper complexation. This nanoreactor is constructed using functionalized MSN incorporating benzoyl thiourea (BTU), triphenylphosphine (TPP), and folic acid (FA), while being co-loaded with horseradish peroxidase (HRP) and its substrate ABTS. During therapy, the BTU moieties on AH@MBTF could capture excessive copper (highly correlated with tumor metastasis), presenting exceptional anti-metastasis activity. Simultaneously, the complexation between BTU and copper triggers the formation of cuprous ions, which further react with H2O2 to generate cytotoxic hydroxyl radical (•OH), inhibiting tumor growth via chemodynamic therapy. Additionally, the stepwise targeting of FA and TPP guides AH@MBTF to accurately accumulate in tumor mitochondria, containing abnormally high levels of H2O2. As a catalyst, HRP mediates the oxidation reaction between ABTS and H2O2 to yield activated ABTS•+. Upon 808 nm laser irradiation, the activated ABTS•+ performs tumor-specific photothermal therapy, achieving the ablation of primary tumor by raising the tissue temperature. Collectively, this intelligent nanoreactor possesses profound potential in inhibiting tumor progression and metastasis.

Dauricine attenuates Oct4/sonic hedgehog co-activated stemness and induces reactive oxygen species-mediated mitochondrial apoptosis via AKT/ß-catenin signaling in human neuroblastoma and glioblastoma stem-like cells.

Neuroblastoma and glioblastoma are primary malignant tumors of the nervous system, with frequent relapse and limited clinical therapeutic drugs. The failure of their treatment is due to the tumor cells exhibiting cancer stem-like cells (CSLCs) properties. Octamer binding transcription factor 4 (Oct4) is involved in mediating CSLCs, our previous work found that Oct4-driven reprogramming of astrocytes into induced neural stem cells was potentiated with continuous sonic hedgehog (Shh) stimulation. In this study, we aimed to study the importance of Oct4 and Shh combination in the stemness properties induction of neuroblastoma and glioblastoma cells, and evaluate the anti-stemness effect of dauricine (DAU), a natural product of bis-benzylisoquinoline alkaloid. The effect of Oct4 and Shh co-activation on cancer stemness was evaluated by tumor spheres formation model and flow cytometry analysis. Then the effects of DAU on SH-SY5Y and T98-G cells were assessed by the MTT, colony formation, and tumor spheres formation model. DAU acts on Oct4 were verified using the Western blotting, MTT, and so on. Mechanistic studies were explored by siRNA transfection assay, Western blotting, and flow cytometry analysis. We identified that Shh effectively improved Oct4-mediated generation of stemness in SH-SY5Y and T98-G cells, and Oct4 and Shh co-activation promoted cell growth, the resistance of apoptosis. In addition, DAU, a natural product, was found to be able to attenuate Oct4/Shh co-activated stemness and induce cell cycle arrest and apoptosis via blocking AKT/ß-catenin signaling in neuroblastoma and glioblastoma, which contributed to the neuroblastoma and glioblastoma cells growth inhibition by DAU. In summary, our results indicated that the treatment of DAU may be served as a potential therapeutic method in neuroblastoma and glioblastoma.

Expression of PGRMC1 in patients with polycystic ovary syndrome and its molecular mechanism for regulating ovarian granulosa cell apoptosis and glucolipid metabolism. / PGRMC1åœ¨å¤šå›Šåµå·¢ç»¼åˆå¾æ‚£è€ ä¸­çš„è¡¨è¾¾åŠå ¶è°ƒæŽ§åµå·¢é¢—ç²’ç»†èƒžå‡‹äº¡å’Œç³–è„‚ä»£è°¢çš„åˆ†å­æœºåˆ¶.

OBJECTIVES: Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases in women with reproductive age, which is associated with hyperandrogenism, insulin resistance, and ovulatory dysfunction. Progesterone receptor membrane component 1 (PGRMC1) can mediate progesterone to inhibit the apoptosis of ovarian granulosa cells and the growth of follicles, and to induce glucolipid metabolism disorder in ovarian granulosa cells, which is closely related to the occurrence and development of PCOS. This study aims to determine the expression of PGRMC1 in serum, ovarian tissue, ovarian granulosa cells, and follicular fluid in PCOS patients and non-PCOS patients, analyze the value of PGRMC1 in diagnosis and prognosis evaluation of PCOS, and investigate its molecular mechanism on ovarian granulosa cell apoptosis and glucolipid metabolism. METHODS: A total of 123 patients were collected from the Department of Obstetrics and Gynecology in Guangdong Women and Children Hospital (hereinafter referred to as "our hospital") from August 2021 to March 2022 and divided into 3 groups: a PCOS pre-treatment group (n=42), a PCOS treatment group (n=36), and a control group (n=45). The level of PGRMC1 in serum was detected by enzyme linked immunosorbent assay (ELISA). The diagnostic and prognostic value of PGRMC1 was evaluated in patients with PCOS by receiver operating characteristic (ROC) curve. Sixty patients who underwent a laparoscopic surgery from the Department of Obstetrics and Gynecology in our hospital from January 2014 to December 2016 were collected and divided into a PCOS group and a control group (n=30). The expression and distribution of PGRMC1 protein in ovarian tissues were detected by immunohistochemical staining. Twenty-two patients were collected from Reproductive Medicine Center in our hospital from December 2020 to March 2021, and they divided into a PCOS group and a control group (n=11). ELISA was used to detect the level of PGRMC1 in follicular fluid; real-time RT-PCR was used to detect the expression level of PGRMC1 mRNA in ovarian granulosa cells. Human ovarian granular cell line KGN cells were divided into a scrambled group which was transfected with small interfering RNA (siRNA) without interference and a siPGRMC1 group which was transfected with specific siRNA targeting PGRMC1. The apoptotic rate of KGN cells was detected by flow cytometry. The mRNA expression levels of PGRMC1, insulin receptor (INSR), glucose transporter 4 (GLUT4), very low density lipoprotein receptor (VLDLR), and low density lipoprotein receptor (LDLR) were determined by real-time RT-PCR. RESULTS: The serum level of PGRMC1 in the PCOS pre-treatment group was significantly higher than that in the control group (P<0.001), and the serum level of PGRMC1 in the PCOS treatment group was significantly lower than that in the PCOS pre-treatment group (P<0.001). The areas under curve (AUC) of PGRMC1 for the diagnosing and prognosis evaluation of PCOS were 0.923 and 0.893, respectively, and the cut-off values were 620.32 and 814.70 pg/mL, respectively. The positive staining was observed on both ovarian granulosa cells and ovarian stroma, which the staining was deepest in the ovarian granulosa cells. The average optical density of PGRMC1 in the PCOS group was significantly increased in ovarian tissue and ovarian granulosa cells than that in the control group (both P<0.05). Compared with the control group, the PGRMC1 expression levels in ovarian granulosa cells and follicular fluid in the PCOS group were significantly up-regulated (P<0.001 and P<0.01, respectively). Compared with the scrambled group, the apoptotic rate of ovarian granulosa cells was significantly increased in the siPGRMC1 group (P<0.01), the mRNA expression levels of PGRMC1 and INSR in the siPGRMC1 group were significantly down-regulated (P<0.001 and P<0.05, respectively), and the mRNA expression levels of GLUT4, VLDLR and LDLR were significantly up-regulated (all P<0.05). CONCLUSIONS: Serum level of PGRMC1 is increased in PCOS patients, and decreased after standard treatment. PGRMC1 could be used as molecular marker for diagnosis and prognosis evaluation of PCOS. PGRMC1 mainly localizes in ovarian granulosa cells and might play a key role in regulating ovarian granulosa cell apoptosis and glycolipid metabolism.

Association between preconception anti-androgen therapy and pregnancy outcomes of patients with PCOS: A prospective cohort study.

Background: Polycystic ovary syndrome (PCOS) not only increases fertility challenges for women of reproductive age, but also leads to increased complications during pregnancy and even affects the birth weight of newborns. Also, hyperandrogenemia is associated with lower pregnancy rates and lower live birth rates and may even play a role in preterm delivery and pre-eclampsia in patients with PCOS. However, it is still controversial whether PCOS patients are treated with androgen-lowering therapy before pregnancy. Objective: To assess the effect of anti-androgen therapy prior to ovulation induction on maternal and infant pregnancy outcomes in patients with PCOS. Methods: Prospective cohort study. Results: A total of 296 patients with PCOS were enrolled in the study. The prevalence of adverse pregnancy outcomes, and neonatal complications was lower in DRSP(with drospirenone ethinyl estradiol tablets (II) pretreatment) group than in NO-DRSP(without drospirenone ethinyl estradiol tablets (II) pretreatment) groups (DRSP vs. NO-DRSP: adverse pregnancy outcomes, 12.16% vs. 27.03%, P=0.001; neonatal complications, 17.16% vs. 36.67%, P<0.001). No significant difference was found in maternal complications. Further subgroup analysis revealed that PCOS with pretreatment decreased the risk of preterm delivery (2.99% vs. 10.00%; Adjusted RR, 3.80; 95% CI, 1.19-12.13), pregnancy loss (9.46% vs. 18.92%; Adjusted RR, 2.07; 95% CI, 1.08-3.96), low birth weight (0.75% vs 7.50%; Adjusted RR, 12.08; 95% CI, 1.50-97.31), fetal malformations(1.49% vs. 8.33%; Adjusted RR, 5.63; 95% CI, 1.20-26.33).There were no significant differences in the incidence of DM and PIH as pregnancy complications between the two groups (P>0.05). Conclusion: Our findings suggest that preconception androgen-lowering therapy in patients with PCOS improves pregnancy outcomes and reduces neonatal complications.

A case of polycystic ovary syndrome with inevitable miscarriage and multi-site venous thrombosis caused by hereditary protein C deficiency.

BACKGROUND: Polycystic ovarian syndrome (PCOS) affects up to 18% of reproductive-aged women and raises the risk of venous thromboembolic disease (VTE), due to metabolic features and an apparent fibrinolytic state. Recent studies have shown an increased risk of VTE (1.5- to 2-fold) in patients with PCOS as compared to those without PCOS. Mutations in the Protein C (PC) gene (PROC) lead to deficiency or dysfunction of the protein, Protein C deficiency is the main clotting physiological inhibitor of protein C cofactors, and is a risk factor for venous thrombosis, which can cause a variety of events, including miscarriage. This case report proposes a correlation between PCOS, protein C deficiency, venous thrombosis and inevitable miscarriage. CASE PRESENTATION: A 33-year-old Chinese woman was diagnosed with Polycystic Ovary Syndrome (PCOS) in 2015. During the course of treatment, she took ethinylestradiol and cyproterone acetate tablets for more than one year. In 2016, she was sent to a hospital for emergency care due to explosive thrombosis (thrombosis in multiple parts of the body and pulmonary thrombosis). In 2020, the patient became pregnant via natural means and came to our hospital for treatment. During the second trimester, she experienced an inevitable miscarriage. High-throughput sequencing (NGS) of peripheral blood lymphocytes revealed that the patient had a protein C deficiency resulting from a heterozygous mutation deletion of 572_574 in exon 7. CONCLUSION: PC deficiency in conjunction with PCOS and the concomitant use of oral contraceptive (COC) would increase the risk of VTE, especially in the early stages of COC use.

Proteomics analysis of potential serum biomarkers for insulin resistance in patients with polycystic ovary syndrome.

The aim of the present study was to identify potential serum biomarkers for insulin resistance (IR) in patients with polycystic ovary syndrome (PCOS) by comparing the differences in serum protein expression levels between PCOS patients with and without IR. PCOS patients aged from 18 to 35 years were recruited at Guangdong Women and Children's Hospital from January, 2013 to February, 2014. A total of 218 PCOS patients were enrolled and divided into the insulin resistance (PCOS­IR) and non­insulin resistance (PCOS­NIR) groups according to their homeostasis model assessment of insulin resistance. Two­dimensional difference gel electrophoresis (2D­DIGE) and matrix­assisted laser desorption/ionization time­of­flight mass spectrometry (MALDI­TOF­MS/MS) techniques were used to identify differences in protein expression levels between the PCOS­IR and PCOS­NIR groups. The present study demonstrated that the total cholesterol (TCH), triglycerides (TG), low­density lipoprotein (LDL), fasting plasma glucose (FPG), 3­h blood glucose (3hBG) and uric acid (UA) levels in the PCOS­IR group were higher than those in the PCOS­NIR group (P<0.05). Between the PCOS­IR and PCOS­NIR groups, a total of 20 differentially expressed protein spots were detected by 2D­DIGE. Among these, 4 proteins, namely afamin, serotransferrin, complement C3 and apolipoprotein C3 (APOC3), were also identified by MALDI­TOF­MS/MS. The alteration of APOC3 was further confirmed by western blot analysis and enzyme­linked immunosorbent assay (ELISA). The present study also confirmed that the expression level of APOC3 was positively associated with the homeostasis model assessment of insulin resistance (HOMA­IR). On the whole, the data indicate that APOC3 may be a potential diagnostic marker for PCOS­IR patients.

Effectiveness and safety assessment of drospirenone/ethinyl estradiol tablet in treatment of PCOS patients: a single center, prospective, observational study.

BACKGROUND: To investigate the effectiveness and safety of 3 mg drospirenone and 20 µg ethinyl estradiol tablet (3 mg DRSP/20 µg EE) in the treatment of polycystic ovary syndrome (PCOS). METHODS: This single center, prospective observational study was conducted in 140 patients with PCOS. They were prescribed 3 mg DRSP/20 µg EE in a 24/4/ regimen for 3 months. Patients were instructed to take oral DRSP/EE tablets (once daily) on the 2nd day of menstruation, for 28 consecutive days for 1 cycle. After 3 months of treatment, anthropometric assessments along with variations in sex hormones related index, glucolipid metabolic index, changes in bilateral ovarian volume, as well as adverse effect of the combination were evaluated. RESULTS: When compared to baseline, body mass index (BMI, 22.07 ± 4.09 vs. 21.35 ± 3.22, p < 0.001) and waist hip ratio (WHR, 0.86 ± 0.07 vs. 0.854 ± 0.06, p = 0.026) decreased significantly after treatment. Sex-hormones such as luteinizing hormone (LH) (10.88 vs. 5.81 U/L), testosterone (T) (1.85 vs. 1.51 nmol/L) and free androgen index (FAI) (5.37 vs. 1.50) decreased significantly after treatment (p < 0.001). Follicular stimulating hormone (FSH) increased significantly at 3 months as compared to before treatment (5.13 vs. 5.42 U/L, p = 0.009). Plasma insulin (11.03 vs. 11.10 pmol/L), fasting (4.97 vs. 4.93 mmol/L) and 2 h-blood glucose levels (7.18 vs. 7.04 mmol/L) did not change when compared to baseline. Plasma triglycerides (TG, 1.32 vs. 1.65 mmol/L) significantly increased 3 months after treatment when compared to before treatment (p < 0.001). However, high density lipoprotein-cholesterol (HDL-C) levels increased significantly after treatment (1.41 vs. 1.57 mmol/L, p < 0.001). It was seen that, when compared to baseline, bilateral ovarian volume (left and right) was significantly lower after treatment (p < 0.05). It was seen that 81 patients reported no adverse reactions. Of the common discomforts reported, breast swelling and pain, gastrointestinal disorder and dizziness and headache were most frequent. CONCLUSIONS: Treatment of PCOS patients with3 mg DRSP/20 µg EE has shown beneficial hormonal and lipid profile along with considerable safety profile. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1900022001, March 2019, retrospectively registered.

Chronic nodules of sigmoid perforation caused by incarcerated intrauterine contraception device.

RATIONALE: It is extremely rare for an intrauterine contraception device (IUD) to cause uterine perforation and Sigmoid perforation for a long time without being detected. PATIENT CONCERNS: We present a case of a patient who has suffered from abdominal pain after 4 years of placement of an IUD, and found that the IUD was incarcerated by ultrasound. DIAGNOSES: Laparoscopic and hysteroscopic examination revealed that the incarcerated IUD caused uterine perforation and sigmoid perforation for a long time. One end of the intrauterine device completely penetrated the anterior wall muscle layer of the uterus and the full layer of the sigmoid colon, located in the intestinal lumen, and the perforated portion of the sigmoid colon formed a chronic nodule. INTERVENTIONS: We extended the sigmoid colon perforation and uterine perforation by laparoscopy, removed the incarcerated IUD from the uterus through the vagina, trimmed the chronic nodules of the sigmoid perforation, repaired the sigmoid colon, and repaired the uterine perforation. OUTCOMES: The patient was cured and discharged 22 days after surgery. The patient was naturally pregnant 3 months after surgery and delivered by cesarean section 12 months after surgery. We saw a good recovery of the uterus and sigmoid colon during cesarean section. LESSONS: The patient was placed with an intrauterine device made of a special material and was not monitored after placement, causing the uterus and sigmoid perforation to be undetected for a long time. The IUD placed in the patient should be monitored regularly. If the IUD is found to be incarcerated or displaced, attention should be paid to uterine perforation and intestinal perforation.

Investigations on the mechanism of progesterone in inhibiting endometrial cancer cell cycle and viability via regulation of long noncoding RNA NEAT1/microRNA-146b-5p mediated Wnt/ß-catenin signaling.

Progesterone is often used to protect the endometrium and prevent endometrial cancer. An intensive study on its molecular mechanism in endometrial cancer would contribute to the development of more promising therapies. Relevant lncRNAs and mRNAs expression data in endometrial cancer cell line Ishikawa pretreated and post-treated with progesterone were derived from Gene Expression Omnibus (accession no. GSE29435), and then we analyzed long noncoding RNAs and mRNAs with differential expressions in two different conditions. The Cytoscape software, TargetScan, miRanda, and Human microRNA Disease Database (HMDD) websites were employed. Gene set enrichment analysis (GSEA) was used to determine related Kyoto Encyclopedia of Genes and Genomes pathways alteration in Ishikawa cells treated with progesterone. In addition to bioinformatics analysis, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blot, and dual-luciferase reporter assays were performed. The impact of progesterone on cell propagation and cell cycle was testified by colony formation and flow cytometry analysis. LncRNA nuclear enriched abundant transcript 1 (NEAT1) was the most significantly downregulated lncRNA in endometrial cancer cells treated with progesterone. Lymphoid enhancing factor 1 (LEF1) was positively associated with NEAT1, and eventually hsa_miR-146b-5p was validated to target both LEF1 and NEAT1. Wnt/ß-catenin signaling pathway was identified to involve in endometrial cancer. NEAT1 or LEF1 was overexpressed in endometrial cancer cells while downregulated following post-treatment with progesterone. Conversely, miR-146b-5p was notably decreased in Ishikawa cells while upregulated after treatment with progesterone. Downstream gene c-myc or MMP9 regulated by upstream gene LEF1 in Wnt/ß-catenin signaling pathway was remarkably increased in Ishikawa cells and positively related with NEAT1. Progesterone inhibited cell cycle and viability through regulating NEAT1/miR-146b-5p axis via Wnt/ß-catenin signaling pathway. Progesterone exerted suppressive influence on endometrial cancer progression via regulation of lncRNA NEAT1/miR-146b-5p-mediated Wnt/ß-catenin signaling pathway, which might reveal new strategies for developing more effective therapeutics. © 2018 IUBMB Life, 71(1):223-234, 2019.

Photochemical Vapor Generation of Tellurium: Synergistic Effect from Ferric Ion and Nano-TiO2.

Photochemical vapor generation (PVG) is emerging as a promising analytical tool for Te determination, thanks to its efficient matrix separation, and simple and green procedure. However, the low PVG generation efficiency of Te is the bottleneck for its wide application in environmental samples containing trace Te. Herein, we reported a high efficient PVG for Te determination by synergistic effect of ferric ion and nano-TiO2. The analytical sensitivity was enhanced approximately 15-fold for Te(IV) in the presence of both ferric ions and nano-TiO2, comparing to conventional PVG. Besides, the use of nano-TiO2 can provide Te(VI) and Te(IV) an equal and high PVG efficiency in the presence of ferric ions, owned to the high photocatalytic performance of TiO2 under short-wavelength UV irradiation (254 and 185 nm). Under the optimized experimental conditions, a detection limit of 1.0 ng L-1 was obtained. The precision of replicate measurements was 2.3% (RSD, n = 7) at 0.5 µg L-1 for Te(IV). The methodology was validated by successful determination of Te in surface waters and two standard reference sediment samples. To our best knowledge, this is the first report of the synergistic enhancement of transitional metal ions and nano-TiO2 in PVG, which possesses potential for highly sensitive determination of vapor-forming elements.

The Role of Heat Shock Protein 90B1 in Patients with Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a heterogenetic disorder in women that is characterized by arrested follicular growth and anovulatory infertility. The altered protein expression levels in the ovarian tissues reflect the molecular defects in folliculogenesis. To identify aberrant protein expression in PCOS, we analyzed protein expression profiles in the ovarian tissues of patients with PCOS. We identified a total of 18 protein spots that were differentially expressed in PCOS compared with healthy ovarian samples. A total of 13 proteins were upregulated and 5 proteins were downregulated. The expression levels of heat shock protein 90B1 (HSP90B1) and calcium signaling activator calmodulin 1 (CALM1) were increased by at least two-fold. The expression levels of HSP90B1 and CALM1 were positively associated with ovarian cell survival and negatively associated with caspase-3 activation and apoptosis. Knock-down of HSP90B1 with siRNA attenuated ovarian cell survival and increased apoptosis. In contrast, ovarian cell survival was improved and cell apoptosis was decreased in cells over-expressing HSP90B1. These results demonstrated the pivotal role of HSP90B1 in the proliferation and survival of ovarian cells, suggesting a critical role for HSP90B1 in the pathogenesis of PCOS. We also observed a downregulation of anti-inflammatory activity-related annexin A6 (ANXA6) and tropomyosin 2 (TPM2) compared with the normal controls, which could affect cell division and folliculogenesis in PCOS. This is the first study to identify novel altered gene expression in the ovarian tissues of patients with PCOS. These findings may have significant implications for future diagnostic and treatment strategies for PCOS using molecular interventions.

Breastfeeding patterns of primiparous mothers in Hong Kong.

BACKGROUND: An understanding of patterns of breastfeeding is necessary for the effective implementation of breastfeeding promotion and intervention programs. In Hong Kong, little current data have been gathered on women's breastfeeding rates. The objective of this study was to determine how patterns of breastfeeding, maternal demographics, and maternal employment affect continuation of breastfeeding in primiparous women in Hong Kong. METHOD: A longitudinal self-report survey was used to collect data when first-time mothers (n=218) were in the hospital, at 1, 3, 6, 9, and 12 months postpartum, or until they weaned their infant. All data (self-report survey, demographic data, and follow-up telephone surveys) were collected in Cantonese and then translated into English. Data were analyzed by determining, first, the influence of individual variables on the length of breastfeeding using a simple Cox regression analysis, and second, by grouping variables according to time sequence and entering them into a Cox regression model in 4 sequential phases. RESULTS: Factors that were significantly associated with continuation of breastfeeding were maternal age (HR=0.97; p=0.048); attendance at a prenatal breastfeeding class (HR=0.69; p=0.020); intended weeks of breastfeeding (HR=0.97; p<0.001); breastfeeding score in hospital (HR=0.99; p=0.009); and length of exclusive breastfeeding (HR=0.93; p<0.001). Similar results were obtained in the multiphase Cox regression analysis; only the breastfeeding score in hospital became marginally insignificant (p=0.053) after adjusting for demographics, prenatal, and other immediate postpartum factors. CONCLUSIONS: Short periods of exclusive breastfeeding and early supplementation were common in this sample. Unlike previous research, maternal employment was not a statistically significant factor in length of continued breastfeeding. Study findings show that multiple factors influence continued breastfeeding in Hong Kong, suggesting further areas for investigation. Changes in practice may improve continued and exclusive breastfeeding rates.