G3SR: Global Graph Guided Session-Based Recommendation.

Session-based recommendation tries to make use of anonymous session data to deliver high-quality recommendations under the condition that user profiles and the complete historical behavioral data of a target user are unavailable. Previous works consider each session individually and try to capture user interests within a session. Despite their encouraging results, these models can only perceive intra-session items and cannot draw upon the massive historical relational information. To solve this problem, we propose a novel method named global graph guided session-based recommendation (G3SR). G3SR decomposes the session-based recommendation workflow into two steps. First, a global graph is built upon all session data, from which the global item representations are learned in an unsupervised manner. Then, these representations are refined on session graphs under the graph networks, and a readout function is used to generate session representations for each session. Extensive experiments on two real-world benchmark datasets show remarkable and consistent improvements of the G3SR method over the state-of-the-art methods, especially for cold items.

Comparison of oblique and transforaminal approaches to lumbar interbody fusion for lumbar degenerative disease: An updated meta-analysis.

Objective: Oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) are widely used in the treatment of lumbar degenerative diseases. A meta-analysis was performed to examine the clinical and radiological effects of these two techniques. Methods: A search of relevant literature from several databases was conducted until November 2021. Perioperative outcomes, clinical and radiological results, and complications were analyzed. Results: Fifteen qualified studies were included. OLIF showed a shorter operative time and length of hospital stay and less blood loss than TLIF. Early postoperative Visual Analogue Scale for back pain were significantly lower in OLIF than in TLIF (P = 0.004). Noteworthy, although the preoperative Oswestry Disability Index (ODI) of the OLIF group was higher than that of the TLIF group (P = 0.04), the postoperative ODI was significantly lower (P < 0.05). Radiologically, the results showed that the disc and foraminal heights of OLIF were significantly higher than those of TLIF postoperatively. Moreover, OLIF can restore more segmental lordosis than TLIF in the early postoperative period. Furthermore, OLIF showed better fusion rates than TLIF (P = 0.02), with no difference in cage subsidence (13.4% vs. 16.6%). No significant differences in overall and approach-related complications between the two groups. Conclusion: The OLIF group showed an advantage in terms of operative time, hospitalization, intraoperative blood loss, early back pain relief, postoperative function recovery, disc and foraminal heights, early segmental lordosis, and fusion rate compared to TLIF. For both procedures, the incidence rates of overall and approach-related complications were comparable.

Identification of the first case of SFTSV infection in the Hunan Province of China and epidemiological surveillance in the locality.

This study reports the etiological identification, clinical diagnosis, and the results of the local epidemiological surveillance of the first case of severe fever with thrombocytopenia syndrome virus (SFTSV) infection in 2014 in Hunan Province, China. The infected patient was isolated and closely monitored. The virus is a member of the Bunyaviridae sandfly family and is characterized by real-time PCR, electron microscopy, immunofluorescence, and whole-genome sequencing. We also detected IgG and IgM antibodies against SFTSV among the local human population and domestic animals in a serological surveillance. Prevalence of SFTSV-specific antibodies was monitored in the local population for two years after the identification of the first SFTS case. Approximately 5% (4/77) of the people who had direct contact with the patient were seropositive, which is significantly higher than the seropositivity of the general local population [1.57% (44/2800), P < 0.05]. Furthermore, the percentage of the general population who were seropositive was higher in 2015 than in 2014 (χ2 = 7.481, P = 0.006). The epidemiological investigation found that the SFTSV is epidemic in goats, cattle, and chickens in Hunan Province. The risk of infection of domestic animals can be minimized by feeding in pens rather than allowing foraging.

Serendipitous Recommendation in E-Commerce Using Innovator-Based Collaborative Filtering.

Collaborative filtering (CF) algorithms have been widely used to build recommender systems since they have distinguishing capability of sharing collective wisdoms and experiences. However, they may easily fall into the trap of the Matthew effect, which tends to recommend popular items and hence less popular items become increasingly less popular. Under this circumstance, most of the items in the recommendation list are already familiar to users and therefore the performance would seriously degenerate in finding cold items, i.e., new items and niche items. To address this issue, in this paper, a user survey is first conducted on the online shopping habits in China, based on which a novel recommendation algorithm termed innovator-based CF is proposed that can recommend cold items to users by introducing the concept of innovators. Specifically, innovators are a special subset of users who can discover cold items without the help of recommender system. Therefore, cold items can be captured in the recommendation list via innovators, achieving the balance between serendipity and accuracy. To confirm the effectiveness of our algorithm, extensive experiments are conducted on the dataset provided by Alibaba Group in Ali Mobile Recommendation Algorithm Competition, which is collected from the real e-commerce environment and covers massive user behavior log data.

Hand, Foot, and Mouth Disease in Hunan Province, China, 2009-2014: Epidemiology and Death Risk Factors.

Hand, foot, and mouth disease (HFMD) is an arising public health problem in Asia, including China. Epidemiological data is necessary to enable judicious public health responses and interventions. We analyzed the epidemiological and laboratory data of 759,301 HFMD cases reported to the Hunan Provincial Center for Disease Control and Prevention from 1 January 2009 to 31 December 2014. Univariate and multivariable conditional logistic regression analyses were used to identify risk factors of fatality in HFMD. The incidence of HFMD was highest among children aged 1-3 years, compared with other age groups. Of the total HFMD cases, 7,222 (0.95%) were considered severe and 338 (0.04%) were fatal. Enterovirus-A71 was the major cause of severe and fatal cases (65.75% and 88.78%, respectively). For severe cases, the median time from symptom onset to diagnosis was 0.5 days (interquartile range [IQR] 0-1.5 days); the median time from diagnosis to severe illness was 2 days (IQR 1-3 days). For fatal cases, the median time from symptom onset to diagnosis was 0.5 days (IQR 0-1.5 days); the median time from diagnosis to death was 1.5 days (IQR 0.5-2.5 days). In multivariable analysis, the abuse of antibiotic, glucocorticoid and pyrazolone in village clinics at basic medical institutions were identified as independent risk factors for HFMD fatal cases. In conclusion, our results suggest that the future direction to control and respond to HFMD is intensive surveillance of enterovirus-A71 and improving the ability to diagnose disease and treat patients, especially in basic medical institutions.

Mining Top K Spread Sources for a Specific Topic and a Given Node.

In social networks, nodes (or users) interested in specific topics are often influenced by others. The influence is usually associated with a set of nodes rather than a single one. An interesting but challenging task for any given topic and node is to find the set of nodes that represents the source or trigger for the topic and thus identify those nodes that have the greatest influence on the given node as the topic spreads. We find that it is an NP-hard problem. This paper proposes an effective framework to deal with this problem. First, the topic propagation is represented as the Bayesian network. We then construct the propagation model by a variant of the voter model. The probability transition matrix (PTM) algorithm is presented to conduct the probability inference with the complexity O(θ(3)log2θ), while θ is the number nodes in the given graph. To evaluate the PTM algorithm, we conduct extensive experiments on real datasets. The experimental results show that the PTM algorithm is both effective and efficient.

Correlation analysis of EV71 detection and case severity in hand, foot, and mouth disease in the Hunan Province of China.

An increase in the incidence of hand, foot and mouth disease (HFMD) cases has been observed in the Hunan province of mainland China since 2009 with a particularly higher level of severe cases in 2010-2012. Intestinal viruses of the picornaviridae family are responsible for the human syndrome associated with HFMD with enterovirus 71 (EV71) and Coxsackievirus A16 (Cox A16) being the most common causative strains. HFMD cases associated with EV71 are generally more severe with an increased association of morbidity and mortality. In this study, the etiology surveillance data of HFMD cases in Hunan province from March 2010 to October 2012 were analyzed to determine if there is a statistically relevant linear correlation exists between the detection rate of EV71 in mild cases and the proportion of severe cases among all HFMD patients. As the cases progressed from mild to severe to fatal, the likelihood of EV71 detection increased (25.78%, 52.20% and 84.18%, respectively). For all cases in the timeframe evaluated in this study, the presence of virus was detected in 63.21% of cases; among cases showing positivity for virus, EV71 infection accounted for 50.14%. These results provide evidence to support the observed higher morbidity and mortality associated with this outbreak and emphasizes the importance of early detection in order to implement necessary prevention measures to mitigate disease progression.

[Virological surveillance of pandemic (H1N1) 2009 virus and its genetic characteristics in Hunan Province, 2009-2011].

To understand and master the dynamic variation of the pandemic influenza A (H1N1) 2009 in Hunan province from 2009 to 2011, and to know the genetic characteristics and drug resistance of the pandemic (H1N1) 2009 viruses. Throat swab specimens of influenza-like illness patients were collected from sentinel hospitals and tested for influenza by fluorescent PCR or virus isolation methods. Partial isolates were selected for sequencing. The sequences were used for phylogenetic analysis by MEGA 5. 05 software. From the 20th week of 2009 to the 52nd week of 2011, 17 773 specimens were tested. 3 831 specimens were influenza-positive with a positive rate of 21. 6%, of which 1 794 were positive specimens of pandemic (H1N1) 2009, accounting for 46. 8%00 of the influenza-positives. There were 2 epidemic peaks of pandemic (H1N1) 2009, which were in the 41st-53rd week of 2009 and the 1st-12nd week of 2011, respectively. The HA genes of 23 strains that were selected for sequencing had close relationship; the distribution of strains in the phylogenetic tree was basically in chronological order. The complete genome sequence analysis showed that all of 8 gene segments of 7 strains were homologous to the vaccine strain, and there was no gene reassortment. The HA amino acid sites of the 23 strains were highly similar to the vaccine strain (98. 2% - 100. 0% in homology), but all 23 strains had P83S, S203T and 1321V mutations. The 222 site mutation that may lead to enhanced virulence was found in the A/Hunan/YQ30/2009 strain. The mutation was D222E. There was no oseltamivir resistance mutation found in all strains. The pandemic (H1N1) 2009 in Hunan province from 2009 to 2011 had a bimodal distribution. There was no large-scale variation of virus genes. The clinical use of oseltamivir was still effective. Key words: Pandemic (H1N1) 2009; Surveillance; Genetic characteristics

Insulin-like growth factor-2 antisense oligonucleotides inhibits myopia by expression blocking of retinal insulin-like growth factor-2 in guinea pig.

OBJECTIVE: To clarify the role of IGF-2 on the development of myopia, the dynamic expression of IGF-2 was investigated in the FD eyes' retina, and the effects of intravitreous injection with IGF-2 ASON was studied on the diopter and axial eye length of FD eyes. METHODS: 64 guinea pigs were divided into 2 groups. In group A (n = 24), the right eyes were covered. On days 7, 14 and 21, the diopter, axial eye length and level of IGF-2 of both eyes were measured in every 8 guinea pigs. In group B (n = 40), the right eyes were covered. On day 1, the right eyes were received intravitreal injection with 40 µg IGF-2SON, 10 µg, 20 µg or 40 µg IGF-2 ASON. The diopter, axial eye length and level of IGF-2 were measured on day 14. RESULTS: FD eyes showed myopic shift, axial length enlongation, and up-regulation in retinal IGF-2 from day 7 to day 21. The level of retinal IGF-2 in FD eyes was higher than that in non-FD eyes. Compare with FD eyes without injection, the myopia diopter of FD eyes decreased in received intravitreous injection with IGF-2 ASON, axial length shortened, and down-regulated with retinal IGF-2. With the increase dose of IGF-2 ASON, the change of myopic diopter, axial length, and level of retinal IGF-2 were showed more and more significant. CONCLUSIONS: FD is effective to up-regulate the level of retinal IGF-2 expression in guinea pig. Intravitreous injection with IGF-2 ASON can inhibit the development of myopia.

[Serological survey of pandemic influenza A (H1N1) virus infection among population in Hunan Province].

OBJECTIVE: To understand the infection condition and analytical methods of Influenza A (H1N1) virus in the population of Hunan Province during different periods. METHODS: Quick surveys on the positive rate of Influenza A (H1N1) virus hemagglutination inhibition (HI) test have been conducted for 5 times successively from November 2009 to March 2010 in 14 medical and health institutions of Changsha city, whose results were then compared with those from the sampling surveys of whole Hunan province. RESULTS: 2131 subjects were involved in this study; the total population standardized rates of antibody positive investigated for 5 times were 9.32% , 14.62%, 31.08%, 28.43% and 22.80% respectively; the population of 6-17-years-old has the highest rate of antibody positive; only 9.84% of the antibody positive subjects attributed to vaccine inoculation; there was no significant difference in the standardized positive rates between the quick serological surveys and the corresponding sampling survey of Hunan province (P > 0.05). CONCLUSION: The positive rate of A (H1N1) virus antibody reached the peak in late January 2010; quick investigations in small region could be used to evaluate the infection prevalence during pandemic of infectious diseases.

[The isolation, cultivation and identification of laryngeal mucosal mesenchymal stem cells].

OBJECTIVE: To investigate the presence of mesenchymal stem cells (MSC) in laryngeal mucosa, and to seek for the method to isolate, cultivate and identify these cells. METHODS: Normal laryngeal mucosa was obtained from patients with laryngeal carcinoma during surgery, and the generating mesenchymal cells was obtained by digestive method. The cell growth curve was evaluated by 3-(4.5-methylthiazol-2yl)-2.5-diphenyltetrazolium bromide (MTT) assay. Colony forming cell assay was used to screen different morphologic colonies and evaluate clone formation ability. Flow cytometry was performed for the expression of the cells of the 4th passage surface marker profiles. Multiple differentiation potentials were confirmed by adipogenic, osteogenic and neural lineages induction. RESULTS: MTT assay and colony forming cell assay showed that laryngeal mucosa MSC had a relatively rapid proliferation capacity and a relatively high clone formation capacity (clone formation rate 7.1%). Flow cytometry analysis revealed that the laryngeal mucosa MSC were positive for CD29 (16.9%), CD44 (97.4%), CD90 (89.5%), CD105 (85.9%), CD146 (2.5%) and stro-1 (20.4%), but negative for CD34 (1.2%) and CD45 (0.8%). Laryngeal mucosa MSC undergone adipogenic, osteogenic and neural lineages induction were positive for oil red staining, alizarin red staining and S100 staining respectively, which suggested that laryngeal mucosa MSC could differentiate into adipogenic, osteogenic and neural lineages. CONCLUSION: This study demonstrated that MSC with rapid proliferative capacity and multiple differentiation potential could be obtained from lamina propria of laryngeal mucosa.

[Experimental study on adipose-derived stem cells combined with acellular dermal matrix particles for vocal fold injection].

OBJECTIVE: To explore the feasibility of adipose-derived stem cells (ASC) combined with micronized acellular dermal matrix (MADM) for vocal cord injection. METHODS: The adipose-deprived stem cells were harvested from rabbit adipose tissue in vitro. The 3rd generation of ASC was labeled with DiI (1,1-dioctadecyl-3,3,3,3-tetramethylindocarbocyanine perchlorate) and cultured with MADM to form a complex. The adhesion of ASC to MADM was observed by fluorescence microscope and electron microscope. The proliferation of ASC on MADM was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy methoxyphenyl)-2-(4-sulfonyl)-2H-tetrazolium, inner salt (MTS). Three days after the culture, the complex was mixed with appropriate amount of collagen, and then injected into the unilateral vocal cord of the rabbit. The animals were sacrificed 2, 4, 8 weeks after injection, the survival time and distribution of ASC in vocal fold were tested, and the responses of vocal cord to ASC-MADM and the degradation of MADM were observed. RESULTS: The ASC adhered to MADM and grew well (P < 0.05 or < 0.01), showing good compatibility with MADM in vocal cord tissue. The complex of ASC-MADM could be injected into the rabbit vocal cords, while no adverse reactions was observed in the vocal cord by endoscope, frozen section and HE staining. ASC could survive for 8 weeks in vocal cords, and no inflammatory cell infiltration was observed. CONCLUSIONS: MADM is an ideal scaffold material and shows perfect compatibility with ASC which can adhere and proliferate well on it. The complex of ASC-MADM can be injected into the vocal cord and can survive. There is no adverse reaction in vocal cords.

Supernatant of bone marrow mesenchymal stromal cells induces peripheral blood mononuclear cells possessing mesenchymal features.

Increasing evidence shows that some cells from peripheral blood fibroblast-like mononuclear cells have the capacity to differentiate into mesenchymal lineages. However, the insufficiency of these cells in the circulation challenges the cell isolation and subsequently limits the clinical application of these cells. In the present study, the peripheral blood mononuclear cells (pbMNCs) were isolated from wound animals and treated with the supernatant of bone marrow mesenchymal stromal cells (bmMSCs). Results showed these pbMNCs were fibroblast-like, had stromal morphology, were negative for CD34 and CD45, but positive for Vimentin and Collagen I, and had the multipotency to differentiate into adipocytes and osteoblasts. We named these induced peripheral blood-derived mesenchymal stromal cells (ipbMSCs). Skin grafts in combination with ipbMSCs and collagen I were applied for wound healing, and results revealed ipbMSC exhibited similar potency and effectiveness in the promotion of wound healing to the bmMSCs. Hereafter, we speculate that the mixture of growth factors and chemokines secreted by bmMSCs may play an important roles in the induction of the proliferation and mesenchymal differentiation of mononuclear cells. Our results are clinically relevant because it provide a new method for the acquisition of MSCs which can be used as a candidate for the wound repair.

[Risk factors of death cases of hand-foot-and-mouth disease in Hunan province].

OBJECTIVE: To study risk factors of death cases of hand foot and mouth diseases (HFMD) in Hunan province, so as to provide scientific evidence for further prevention and control. METHODS: The 105 death cases of HFMD between January and October, 2010 in Hunan Province were selected as case group; and the 210 survival cases of serious HFMD, which were matched by gender and resident places with a ratio at 2:1 in the same period in Hunan were selected as control group. The basic information, hospitalized experience and previous medical history had been surveyed and the relevant risk factors were analyzed by single factor and multi-factor logistic regression. RESULTS: In case group, 79.05% (83/105) of the cases lived in rural area and 9.52% (10/105) of the cases lived in urban-rural midst area. In control group, 87.62% (184/210) of the cases lived in rural area and 11.43% (24/210) of the cases lived in urban-rural midst area. In case group, 59.05% (62/105) of the patients first visited rural (private) clinics and 20.00% (21/105) first visited community hospitals in villages and towns; while in control group, 43.81% (92/210) and 13.33% (28/210) chose rural (private) clinics and community hospitals in villages and towns as the first choice respectively.22.86% (24/105) of the case group and 39.05% (82/210) of the control group were diagnosed as HFMD in their first visit to hospital.27.62% (29/105) of the case group and 7.14% (15/210) in control group were provided pyrazolone in the treatment. For glucocorticoid, 80.95% (85/105) and 5.71% (6/105) of the case group were given as treatment by rural (private) clinics and community hospitals in villages and towns separately; while the proportions in the control group were 41.43% (87/210) and 0.48% (1/210) respectively. For antibiotics, 35.24% (37/105) and 23.81% (25/105) of the case group were prescribed by rural (private) clinics and community hospitals in villages and towns separately; while the percentages in the control group were 15.71% (33/210) and 7.14% (15/210). 3.81% (4/105) of the case group and 11.90% (25/210) of the control group were vaccinated in one month before the onset. The results of single-factor logistic regression indicated that living in rural areas (OR = 0.075, 95%CI: 0.016 - 0.343) and in rural-urban midst areas (OR = 0.069, 95%CI: 0.013 - 0.368), diagnosis of HFMD in the first visit to hospital (OR = 0.463, 95%CI: 0.271 - 0.788) and vaccination one month before the onset (OR = 0.293, 95%CI: 0.099 - 0.866) were four protective factors; while rural (private) clinics as the first choice (OR = 4.717, 95%CI: 1.891 - 11.767), community hospital in villages and towns as the first choice (OR = 5.250, 95%CI: 1.883 - 14.641), medication of pyrazolone (OR = 4.961, 95%CI: 2.520 - 9.766), medication of glucocorticoid in rural (private) clinics (OR = 6.009, 95%CI: 3.435 - 10.510) and in community hospital in villages and towns (OR = 12.667, 95%CI: 1.505 - 106.638), medication of antibiotics in rural (private) clinics (OR = 2.918, 95%CI: 1.690 - 5.040) and in community hospital in villages and towns (OR = 4.062, 95%CI: 2.036 - 8.108) were seven risk factors. The results of multi-factors logistic regression showed that medication of pyrazolone (OR = 2.311, 95%CI: 1.062 - 5.030), medication of glucocorticoid in rural (private) clinics (OR = 5.480, 95%CI: 3.039 - 9.880), medication of antibiotics in rural (private) clinics (OR = 2.430, 95%CI: 1.301 - 4.538) and medication of antibiotics in community hospitals in villages and towns (OR = 3.344, 95%CI: 1.477 - 7.569) were the risk factors of death of HFMD. CONCLUSION: The risk factors of HFMD deaths include the medication of pyrazolone, glucocorticoid and antibiotics by rural (private) clinics and medical institutions in villages and towns. The department concerned should revise the technical manual to standardize the medication of the above drugs.

The correlation between the regulation of recombinant human IGF-2 on eye growth and form-deprivation in guinea pig.

OBJECTIVE: By investigating the effects of recombinant human IGF-2 (rhIGF-2) on the diopter, axial eye length and the expression of IGF-2 in non-form-deprivation (FD) and FD eyes of guinea pig, we tried to elucidate the relationship between the effects of rhIGF-2 on eye growth and FD in guinea pig. METHODS: Eighty 3-week-old guinea pigs were included in the study, which were divided into two groups randomly. Group A (n = 40) was the non-FD group, Thirty-two guinea pigs received intravitreal injections of either 1 ng, 10 ng, 100 ng rhIGF-2 or bovine serum albumin (BSA) to the right eye; eight guinea pigs who received no intravitreal injections served as control. Group B (n = 40) was the FD group; the right eyes were form-deprived, and received the same disposals as group A. The diopter and the axial eye length of all guinea pigs were measured at day 14. The expression of IGF-2 in the retina was measured by Western blot. RESULTS: After 14 days, FD eyes were high myopia. The axial length of FD eyes was significant for longer than that of non-FD eyes. The expression of IGF-2 in the retina of FD eyes was up-regulated. In non-FD group, there was no significant difference in the diopter and axial eye length among rhIGF-2 injection eyes, BSA injection eyes and control eyes, but the expression of IGF-2 in the retina of 10 ng and 100 ng rhIGF-2 injection eyes was obviously down-regulated. In the FDM (form-deprivation myopia) group, the myopic diopter and axial eye length increased in 10 ng and 100 ng rhIGF-2 injection eyes compared with those in BSA injection eyes and control eyes. The level of IGF-2 expression in the retina of 10 ng and 100 ng rhIGF-2 injection eyes was obviously down-regulated. The diopter and expression of IGF-2 in the retina of rhIGF-2 injection eyes was negatively correlated with the dose of each injection, which was positively correlated with the axial length. CONCLUSION: RhIGF-2 intravitreous injection does not affect the diopter and axial length in non-FD eyes of guinea pig, while it can induce a significant increase in myopic diopter and axial length of FD eyes. RhIGF-2 can promote the development of FDM on the condition of FD.

TGF-beta2 in human retinal pigment epithelial cells: expression and secretion regulated by cholinergic signals in vitro.

PURPOSE: To investigate the (i) effect(s) of cholinergics on the expression and secretion of transforming growth factor (TGF)-beta(2) in human retinal pigment epithelium (RPE) and (ii) mechanism of action of atropine in the treatment of myopia. MATERIALS AND METHODS: The RPE cell line, D407, was (i) treated with carbachol (10 microM), (ii) treated with atropine (10 nM-100 microM), or (iii) pre-treated with atropine (10 nM-100 microM) and then exposed to carbachol (10 microM). A no-treatment group served as control. Expression of TGF-beta(2), after stimulation at different time points (2, 4, 8, 16, 24, and 48 hr), was measured by RT-PCR and Western blot analysis. Secretion of TGF-beta(2) was determined by ELISA. RESULTS: Carbachol induced a time-dependent increase in the levels of TGF-beta(2) mRNA and protein in the cytoplasm (p < 0.001). ELISA assays showed a time-dependent increase in levels of TGF-beta(2) protein in the supernatant with carbachol treatment (p < 0.001). There was no change of TGF-beta(2) in the cytoplasm or supernatant with atropine alone (p > 0.05). The increased expression and secretion of TGF-beta(2) caused by carbachol were suppressed by atropine (in the range of 10 nM-100 microM) when compared to treatment with carbachol alone (p < 0.001). The stimulating effect of 10 microM carbachol was inhibited completely by 100 microM atropine. CONCLUSIONS: In RPE cells, atropine inhibits the expression and secretion of TGF-beta(2) by blocking the muscarinic acetylcholine receptor (mAChR), which may control the development of myopia.

Odontogenic potential of mesenchymal cells from hair follicle dermal papilla.

Dental pulp stem cells from teeth can be used for tooth regeneration. Although nondental stem cells derived from bone marrow can differentiate into odontoblast-like cells when recombined with embryonic oral epithelium, these cells can lose their ability to differentiate after an extended number of cell culture passages. There has been limited research to identify stem cells from other tissue sources to regenerate teeth. As another candidate source for mesenchymal stem cells, hair follicle has obtained much more attention recently because of its easy accessibility. In this study, cultured vibrissae follicle dermal papilla mesenchymal cells (FDPMCs) from adult C57BL/6 GFP mice can differentiate into adipocytes and osteoblasts in vitro. Moreover, in the inductive microenvironment generated by apical bud and dental mesenchyme from 7-day-old C57 mice, FDPMCs in vitro demonstrated odontogenic potential, as indicated by the morphological transformation, cell-cycle change and expression of tooth-specific markers. Under the same microenvironment, FDPMCs were incubated in vivo for 3 weeks. Coexpression of GFP and DSP proteins in the odontoblast layer was detected in the recovered implants, suggesting that GFP(+) FDPMCs can function as odontoblasts in vivo. Together, our data indicate for the first time that whisker FDPMCs from adult mice can differentiate to odontoblast-like cells.

Identification and characterization of a novel gene, Mcpr1, and its possible function in the proliferation of embryonic palatal mesenchymal cells.

We cloned a novel mouse cDNA, Mcpr1 (mouse cleft palate-related gene 1), between retinoic acid (RA)-treated murine embryonic palatal and control shelves by improved subtractive hybridization. Its transcript was identified by Northern blotting. The open reading frame encodes 132 amino acids and shows almost no identity to other genetic products. Mcpr1 expression could be detected extensively in adult mouse tissues and during murine embryonic development. It was identified to be significantly stimulated by RA in murine palatal shelves at embryonic day 12 and in palatal mesenchymal cells in vitro. We demonstrate that MCPR1 protein was localized primarily in the cytoplasm and could be synthesized and secreted by transfected COS-7 cells. Both the secretory and recombinant proteins of Mcpr1 inhibited proliferation of murine embryonic palatal mesenchymal cells and impeded the progression from the G1 to S phase in the cell cycle. The cells were prone to apoptosis after exposure to glutathione S-transferase-MCPR1. Furthermore, knockdown of MCPR1 protein levels by antisense oligodeoxynucleotides promoted progression of cells from the G1 to S phase and completely abolished the RA-induced block of the cell cycle from the G1 to S phase. These findings suggest that Mcpr1 might function as one of the RA-up-regulated genes involved in inhibiting cell proliferation during palatogenesis and RA-induced cleft palate by regulating proliferation and apoptosis of embryonic palatal mesenchymal cells and might even play a role in the development of many other organs.

ADAM28 participates in the regulation of tooth development.

Disintegrin and metalloprotease (ADAM) proteins are a family of membrane-anchored glycoproteins with diverse functions in fertilisation, development, neurogenesis and protein ectodomain shedding. ADAM28 is a newly discovered member of the ADAM family in humans and murine with autocatalytic activity. Recently, the authors screened ADAM28 genes from patients with congenital hypoplasia of tooth root, and studied the relationship between ADAM28 and tooth development. A polyclonal antibody (pAb) against ADAM28 was preparared, and the expression and localisation of ADAM28 were detected in tooth germ and dental mesenchymal cells. The results indicated that the prokaryotic expression vector pGEX-4T-ADAM28 was constructed successfully. Glutathione S-transferase-ADAM28 fusion protein was generated after inducement by isopropylthio-beta-d-galactoside and isolated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The purified fusion protein was used as an antigen for production of antibody. Western blot and enzyme-linked immunosorbent assay analyses verified that the antibody had a high specificity and titre. Immunohistochemistry and reverse transcriptase-polymerase chain reaction showed that ADAM28 was expressed at each stage of tooth germ development at different levels. Moreover, it was expressed in human dental follicle cells, human dental papilla cells, human dental pulp stem cells, human periodontal ligament cells and human dental cervical loop epithelial cells at transcription level. In conclusion, it is reasonable to suggest that ADAM28 may participate in tooth development and the regulation of odontogenic mesenchymal cells through progressive reciprocal inductive interactions between the epithelium and the mesenchyme.

Enhancement of periodontal tissue regeneration by locally controlled delivery of insulin-like growth factor-I from dextran-co-gelatin microspheres.

The present work focused on the design of novel hydrogel microspheres based on both dextran- and gelatin-derived biomaterials, and discussed whether locally controlled delivery of IGF-I from dextran-co-gelatin hydrogel microspheres (DG-MP) was useful for periodontal regeneration enhancement. Microspheres were synthesized when gelatin was cooperating with glycidyl methacrylate (GMA) derivatized dextrans (Dex-GMA) and the resultant DG-MP with a hydrogel character of which the cross-linking density could be controlled by the degree of substitution (DS, the number of methacrylates per 100 glucopyranose residues) of Dex-GMA. In this study, three types of DG-MP (DG-MP4.7, DG-MP6.3 and DG-MP7.8) obtained from gelatin and Dex-GMA (differing in DS: 4.7, 6.3 and 7.8 respectively) were prepared and characterized by swelling and degradation properties, drug release kinetics and biological capability in promoting tissue regeneration. By swelling in aqueous positively charged IGF-I solutions, the protein could be encapsulated in DG-MP by polyionic complexation with negatively charged acidic gelatin. No obvious influence of Dex-GMA's DS on DG-MP's configuration and size was observed, and the release and degraded properties showed no significant difference between three types of DG-MP in PBS buffer either. However, high DS of Dex-GMA could lower microsphere's swelling, prolong its degraded time and minimize IGF-I burst release markedly in dextranase-containing PBS, where IGF-I release from a slow release type of microspheres (DG-MP7.8) could be maintained more than 28 days, and an effective protein release kinetics without a significant burst but a relevantly constant release after the initial burst was achieved. IGF-I in DG-MP resulted in more new bone formation in the periodontal defects within 4 or 8 weeks than IGF-I in blood clot directly did (P < 0.01). The observed newly formation of periodontal tissues including the height and percentage of new bone and new cementum on the denuded root surfaces of the furcation area in DG-MP7.8 group were more than that in other groups (P < 0.05). The adequate width of regenerative periodontal ligament (PDL), regular Sharpey's fibers and alveolar bone reconstruction could be observed only in DG-MP7.8 group. These combined results demonstrate that effective release kinetics can be realized by adjusting the DS of Dex-GMA and followed cross-linking density of DG-MP, and that locally controlled delivery of IGF-I from slow release type of DG-MP may serve as a novel therapeutic strategy for periodontal tissue regeneration.