[Investigation and analysis of oral health resources allocation status in Yunnan Province]

Objective: To investigate and analyze the allocation status of oral health resources in Yunnan Province at the end of the 13th Five-Year Plan, providing a scientific basis for the rational resource allocation and formulation regional oral health plan for government health administrative departments. Methods: With the method of general survey, a cross-sectional study was conducted to investigate the allocation of material and human resources of all kinds of stomatological medical institutions registered in the health administrative departments in Yunnan before January 1, 2020. The general situation of oral health resources was analyzed by descriptive statistical analysis. Results: There were 2 712 stomatological medical institutions in Yunnan, 634 public and 2 078 non-public included. The largest number was in Kunming (1 167) and the least in Diqing (19). There were 9 018 dental chairs in total, among which 2 584 in public and 6 434 in non-public. Kunming had the largest number of chairs (3 612) and Nujiang had the least (57). There were 702 oral and maxillofacial surgical beds, all of which were distributed in public. There were 15 148 stomatological personnel, including 3 667 in public and 11 481 in non-public. The average ratio of stomatologist to population was 1∶6 615. Dehong (1∶6 620) was close to this average level, while Kunming (1∶2 283) and Yuxi (1∶4 936) were lower than the average and the other 13 states (cities) were higher. The population ratio of licensed stomatologist was only 1∶9 110. The average ratio of stomatologist to nurses was 1∶0.94. Honghe (1∶1.05), Kunming (1∶1.00), Yuxi (1∶1.18) and Qujing (1∶0.94) was better than or reached the average level, while the other 13 states (cities) were lower than this average. And this ratio in public comprehensive medical institutions was only 1∶0.38. Conclusions: The distribution of oral health resources in Yunnan was unbalanced between public and non-public institutions and among states (cities), mainly distributed in economically developed states (cities) and non-public institutions. For the oral health in Yunnan Province, the workforce was insufficient and the structure was unreasonable, and the proportion of nurses was seriously insufficient in public comprehensive medical institutions.

[Study on the prognostic influencing factors of esophageal squamous cell carcinoma and the predictive value of inflammatory reaction indexes on its postoperative recurrence]

Objective: To explore the influence factors of poor prognosis of esophageal squamous cell carcinoma (ESCC) and the predictive value of inflammatory reaction indexes including neutrophils and lymphocytes ratio (NLR), platelet and lymphocyte ratio (PLR), monocyte and lymphocyte ratio (MLR) provision and differentiation degree, infiltration depth, lymph node metastasis number on the postoperative recurrence of ESCC. Methods: A total of 130 patients with ESCC who underwent radical resection from February 2017 to February 2019 in Nanyang Central Hospital were selected and divided into good prognosis group (66 cases) and poor prognosis group (64 cases) according to the prognostic effect. The clinical data and follow-up data were collected. Multivariate logistic regression analysis was used to determine the independent influencing factors of poor prognosis. Spearman correlation analysis was used to determine the correlation between preoperative NLR, PLR and MLR with the degree of differentiation, depth of invasion and number of lymph node metastases. Receiver operating characteristic (ROC) curve analysis was used to evaluate the efficacy of NLR, PLR and MLR in predicting poor prognosis of ESCC. Results: Univariate analysis showed that the degree of differentiation, the degree of invasion and the number of lymph node metastasis were related to the prognoses of patients with ESCC (P<0.05). Multivariate logistic regression analysis showed that the degree of differentiation, depth of invasion and number of lymph node metastases were independent influencing factors for poor prognosis of patients with ESCC, moderate differentiation (OR=2.603, 95% CI: 1.009-6.715) or low differentiation (OR=9.909, 95% CI: 3.097-31.706), infiltrating into fibrous membrane (OR=14.331, 95% CI: 1.333-154.104) or surrounding tissue (OR=23.368, 95% CI: 1.466-372.578), the number of lymph node metastases ≥ 3 (OR=9.225, 95% CI: 1.693-50.263) indicated poor prognosis. Spearman correlation analysis showed that NLR was negatively correlated with the degree of differentiation and the number of lymph node metastases (r=-0.281, P=0.001; r=-0.257, P=0.003), PLR was negatively correlated with the degree of differentiation, depth of invasion and number of lymph node metastasis (r=-0.250, P=0.004; r=0.197, P=0.025; r=-0.194, P=0.027), MLR was positively correlated with the degree of differentiation and the number of lymph node metastasis (r=0.248, P=0.004; r=0.196, P=0.025). ROC curve analysis showed that the areas under the curve of NLR, PLR and MLR in predicting poor prognosis of ESCC were 0.971, 0.925 and 0.834, respectively. The best cut-off value of NLR was 2.87. The sensitivity and specificity of NLR in predicting poor prognosis of ESCC were 90.6% and 87.9%, respectively. The optimal cut-off value of PLR was 141.75. The sensitivity and specificity for predicting poor prognosis of ESCC were 92.2% and 87.9%, respectively. The best cut-off value of MLR was 0.40. The sensitivity and specificity of MLR in predicting poor prognosis of esophageal squamous cell carcinoma were 54.7% and 100.0%, respectively. Conclusions: The degree of differentiation, the degree of invasion and the number of lymph node metastases are closely related to the poor prognosis of patients with esophageal squamous cell carcinoma. NLR, PLR and MLR can provide important information for predicting the poor prognosis of esophageal squamous cell carcinoma.

NLRP6 suppresses the inflammatory response of human periodontal ligament cells by inhibiting NF-κB and ERK signal pathways

AIM

To explore the function and mechanisms of NLRP6 (NOD-, LRR- and pyrin domain-containing 6) in the inflammatory response of human periodontal ligament cells (HPDLCs).

METHODOLOGY

Tissues associated with apical periodontitis were obtained from three patients who underwent endodontic microsurgery. The expression of NLRP6 in 3 human apical periodontitis tissues and HPDLCs was examined by immunohistochemistry and immunofluorescence, respectively. The expressions of NLRP6, Phospho(p)- p65, p65, IκB-α, p- IκB-α, ERK, p- ERK, NLRP3, Pro interleukin (IL)-1β, Pro caspase-1 and apoptosis-associated speck-like protein containing a CARD (ASC) were examined by western blot. The gene expression and secretion of proinflammatory cytokines were detected using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Data were analysed statistically with independent sample t-tests.

RESULTS

NLRP6 was expressed in inflammatory periapical tissues and HPDLCs. Lipopolysaccharide (LPS) from Escherichia coli induced NLRP6 in HPDLCs (P < 0.05). After silencing NLRP6, E. coli LPS-induced activation of NF-κB and ERK signalling was enhanced, which was also accompanied by elevated levels of IL-6 and tumour necrosis factor-α (TNF-α) (P < 0.05). Moreover, knockdown of NLRP6 led to up-regulation of NLRP3, Pro IL-1β and Pro caspase-1 (P < 0.05), whereas down-regulation of ASC (P < 0.05), which may contribute to unchanged levels of IL-1β in HPDLCs inflammation.

CONCLUSION

NLRP6 was functionally expressed in inflamed periapical tissues and HPDLCs. NLRP6 negatively regulated the production of IL-6 and TNF-α in HPDLCs inflammation by inhibiting NF-κB and ERK signal pathways.

[Spectrometric analyses of larotaxel and larotaxel liposomes quantification by high performance liquid chromatography]

OBJECTIVE

Larotaxel is a new chemical structure drug, which has not been marketed worldwide. Accordingly, the standard identification and quantification methods for larotaxel remain unclear. The spectrometric analyses were performed for verifying weight molecular formula, molecular weight and chemical structure of larotaxel. Besides, a quantification method was developed for measuring larotaxel in the liposomes.

METHODS

The molecular formula, molecular weight and chemical structure of larotaxel were studied by using mass spectrometry (MS), infra-red (IR), nuclear magnetic resonance (NMR) and ultraviolet-visible (UV-vis) spectrometric techniques. The absorption wavelength of larotaxel was investigated by UV-vis spectrophotometry full-wavelength scanning. Besides, a quantification method was developed by high performance liquid chromatography (HPLC), and then validated by measuring the encapsulation efficacy of larotaxel liposomes.

RESULTS

The four spectral characteristics of larotaxel were revealed and the corresponding standard spectra were defined. It was confirmed that larotaxel had the structure of tricyclic diterpenoids, with the molecular formula of C45H53NO14, the molecular weight of 831.900 1, and the maximum absorption wavelength of 230 nm. The quantitative method of larotaxel was established by using HPLC with a reversed phase C18 column (5 μm, 250 mm×4.6 mm), a mobile phase of acetonitrile-water (75:25, volume/volume), and a detection wavelength of 230 nm. The validation study exhibited that the established HPLC method was stable, and had a high recovery and precision in the quantitative measurement of larotaxel in liposomes. In addition, a new kind of larotaxel liposomes was also successfully prepared. The particle size of the liposomes was about 105 nm, with an even size distribution. And the encapsulation efficiency of larotaxel in the liposomes was above 80%.

CONCLUSION

The present study offers reference standard spectra of larotaxel, including MS, IR, NMR, and UV-vis, and confirms the molecular formula, molecular weight and chemical structure of larotaxel. Besides, the study develops a rapid HPLC method for quality control of larotaxel liposomes.

The increase of the functional entropy of the human brain with age

We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy.

Effect of stealthy liposomal topotecan plus amlodipine on the multidrug-resistant leukaemia cells in vitro and xenograft in mice

BACKGROUND

Multidrug resistance (MDR) is a major obstacle to successful cancer chemotherapy as the over-expressed MDR protein acts as an efflux pump, which leads to a reduction in the uptake of the anticancer agent by tumour cells. We combined topotecan and amlodipine together into the stealthy liposomes, in which amlodipine was applied as a MDR reversing agent to overcome the resistance.

MATERIALS AND METHODS

Cytotoxicity, apoptosis and the signalling pathway assays were performed on human chronic myelogenous leukaemia K562, promyelocytic leukaemia HL-60 and MDR HL-60 cells, respectively. Pharmacokinetics and antitumour activity studies were performed on normal Kunming mice and female BALB/c nude mice with MDR HL-60 xenografts, respectively.

RESULTS

Topotecan alone was effective in inhibiting the growth of non-resistant leukaemia cells, K562 and HL-60 cells but not the growth of MDR HL-60 cells. The resistance of topotecan in MDR HL-60 cells was potently reversed by the addition of amlodipine. Moreover, amlodipine enhanced the apoptosis-inducing effect of topotecan synergistically. Apoptosis was through activating caspases in a cascade: first, the initiator caspase 8 and then effectors caspase 3/7 (total activity of caspases 3 and 7) were activated. Being encapsulated into the stealthy liposomes with an acidic internal medium, topotecan existed dominantly in an active lactone species, which was reversibly changed from an inactive carboxylate form via a pH-dependent reaction. After administration of stealthy liposomes to mice, the blood exposure of the lactone form was evidently increased and extended. The antitumour effects in the MDR HL-60 xenografted tumour were stealthy liposomal topotecan (SLT) plus amlodipine > SLT > un-encapsulated topotecan > blank control.

CONCLUSIONS

The enhanced antitumour activity in the MDR HL-60 cells by the SLT plus amlodipine could be owing to multiple reasons: (a) synergistic apoptosis inducing effect, (b) reversing MDR by amlodipine and (c) increasing the availability of active lactone of topotecan by the stealthy liposomes. The apoptosis induced by amlodipine is through caspase 8 and then the 3/7 signalling pathway.

In vitro and in vivo study of two types of long-circulating solid lipid nanoparticles containing paclitaxel

Paclitaxel (Taxol), a diterpenoid isolated from Taxus brevifolia, is effective against several murine tumors, and is one of the most exciting anticancer molecules currently available. Due to its low solubility in water, it is clinically administered with polyethoxylated castor oil (Cremophor EL), which causes serious side effects. Inclusion of paclitaxel in solid lipid nanoparticles (SLNs) has proved to be a good approach to eliminate the need for Cremophor EL and improve the drug's antitumor efficacy. This paper describes the development of two types of long-circulating SLNs as colloidal carriers for paclitaxel. SLNs are constituted mainly of bioacceptable and biodegradable lipids. In vitro release kinetics showed that the release was very slow, the release of paclitaxel from F68-SLN is linear, and the release of paclitaxel from Brij78-SLN followed the Weibull equation. Pharmacokinetics was evaluated in KM mice after injection of paclitaxel formulated in Cremophor EL or in Brij78-SLN and F68-SLN. Encapsulation of paclitaxel in both SLNs produced marked differences compared with the free drug pharmacokinetics. F68-SLN and Brij78-SLN are long-circulating (t 1/2 beta, 10.06 and 4.88 h, respectively) compared with paclitaxel injection (t 1/2 beta, 1.36 h).

[A new dynamic model of release for not-corroded drug system--revision and use of Fick's first law]

Based on the facts that the diffusion coefficient in original Fick's first law is not a strict constant but changes with concentration and that the original Fick's first law is only suitable for the stable diffusion with constant concentration gradient but many experiments have shown that the concentration gradient is a function of time. The authors suggest that the diffusion coefficient and the concentration gradient should be revised, respectively, as a concentration function and a time function. That is, [formula: see text] So, the Fick's first law is revised as [formula: see text] In the formula, dW/dt represents the rate of diffusion. D0 is the intrinsic diffusion coefficient that is a constant only concerning the temperature and the character of the substance diffused. A is the area of diffusion surface, alpha is the constant concerning the change of concentration gradient, C0 and C is, respectively, the concentration on the diffusion surface at time t0 and any time t. Based on this, the dynamic model of release on the preparations not-corroded is derived: [formula: see text] Here, k0 is the release constant concerning D0, temperature, C0 and A. The model gave better results than other models in common use for simulating the release dynamic process and the physical meanings of the model parameters are explicit.