Quantitative analysis of sitagliptin using the (19)F-NMR method: a universal technique for fluorinated compound detection.

To expand the application scope of nuclear magnetic resonance (NMR) technology in quantitative analysis of pharmaceutical ingredients, (19)F nuclear magnetic resonance ((19)F-NMR) spectroscopy has been employed as a simple, rapid, and reproducible approach for the detection of a fluorine-containing model drug, sitagliptin phosphate monohydrate (STG). ciprofloxacin (Cipro) has been used as the internal standard (IS). Influential factors, including the relaxation delay time (d1) and pulse angle, impacting the accuracy and precision of spectral data are systematically optimized. Method validation has been carried out in terms of precision and intermediate precision, linearity, limit of detection (LOD) and limit of quantification (LOQ), robustness, and stability. To validate the reliability and feasibility of the (19)F-NMR technology in quantitative analysis of pharmaceutical analytes, the assay result has been compared with that of (1)H-NMR. The statistical F-test and student t-test at 95% confidence level indicate that there is no significant difference between these two methods. Due to the advantages of (19)F-NMR, such as higher resolution and suitability for biological samples, it can be used as a universal technology for the quantitative analysis of other fluorine-containing pharmaceuticals and analytes.

Bibliometric study and review of Klotho research: global characteristics and trends from 2000 to 2023.

BACKGROUND: Although Klotho-related research has seen a significant upsurge, the field lacks comprehensive analytical representation and in-depth exploration of pertinent areas such as prevailing research trends and key focus areas. METHOD: This review presents a bibliometric analysis of literature data gathered from the Web of Science Core Collection databases from January 1, 2000, to April 30, 2023. Parameters such as co-authorship, co-citation, co-occurrence, and the emergence of publications, countries, categories, references, and keywords were scrutinized predominantly using Citespace software. RESULTS: Our investigation amassed a total of 3548 papers, with the United States leading in the quantity of publications (1175, accounting for 33.12%), followed by China (867, representing 24.44%), and Japan (439, accounting for 12.37%). While the United States is preeminent in the overall volume of publications, Scotland holds prominence in terms of centrality. Out of a total of 96 subject categories, urology and nephrology (573), and endocrinology and metabolism (542) were the two leading domains of Klotho-related publications. The 2011 paper titled "FGF23 induces left ventricular hypertrophy" by Faul C et al. holds the distinction of being the most frequently cited. The keywords "fibroblast growth factor 23," "phosphate homeostasis," and "functional variants" demonstrated the highest intensity, underscoring the potential of these research areas. CONCLUSION: As the volume of literature grows, the role of Klotho in disease management and its applicability as a marker in disease progression warrant vigilant tracking and study.

Forecast of peak infection and estimate of excess deaths in COVID-19 transmission and prevalence in Taiyuan City, 2022 to 2023.

In this paper, with the method of epidemic dynamics, we assess the spread and prevalence of COVID-19 after the policy adjustment of prevention and control measure in December 2022 in Taiyuan City in China, and estimate the excess population deaths caused by COVID-19. Based on the transmission mechanism of COVID-19 among individuals, a dynamic model with heterogeneous contacts is established to describe the change of control measures and the population's social behavior in Taiyuan city. The model is verified and simulated by basing on reported case data from November 8th to December 5th, 2022 in Taiyuan city and the statistical data of the questionnaire survey from December 1st to 23rd, 2022 in Neijiang city. Combining with reported numbers of permanent residents and deaths from 2017 to 2021 in Taiyuan city, we apply the dynamic model to estimate theoretical population of 2022 under the assumption that there is no effect of COVID-19. In addition, we carry out sensitivity analysis to determine the propagation character of the Omicron strain and the effect of the control measures. As a result of the study, it is concluded that after adjusting the epidemic policy on December 6th, 2022, three peaks of infection in Taiyuan are estimated to be from December 22nd to 31st, 2022, from May 10th to June 1st, 2023, and from September 5th to October 13th, 2023, and the corresponding daily peaks of new cases can reach 400 000, 44 000 and 22 000, respectively. By the end of 2022, excess deaths can range from 887 to 4887, and excess mortality rate can range from 3.06% to 14.82%. The threshold of the infectivity of the COVID-19 variant is estimated 0.0353, that is if the strain infectivity is above it, the epidemic cannot be control with the previous normalization measures.

[Effects and mechanisms of trophoblast cells autophagy in preeclampsia].

OBJECTIVE: To investigate the occurrence law of autophagy in trophoblast cells from preeclampsia and its underlying mechanisms. METHODS: Twenty cases of placenta tissues were collected from women suffered from preeclampsia and normal pregnant women respectively. Autophagosome of trophoblast cells were observed by transmission electron microscope. The expressions of LC3-II/I and Atg4B in placenta tissues were detected by western blot and real-time PCR. RESULTS: Compared with the control group, typical autophagosomes of trophoblast cells were observed by transmission electron microscope. The ratio of LC3-II/I in placenta of PE patients was increased (1.43 ± 0.23) compared with control group (0.59 ± 0.12), and the expression of Atg4B was up-regulated in both mRNA [(1.73 ± 0.16) folds] and protein levels (0.71 ± 0.13) compared with control group (P < 0.05). CONCLUSIONS: Autophagy was significantly up-regulated in trophoblast cells from patients suffered from preeclampsia. Thus, all the data suggest that autophagy might be involved in the generation of preeclampsia.

Biodiversity of yeasts, lactic acid bacteria and acetic acid bacteria in the fermentation of "Shanxi aged vinegar", a traditional Chinese vinegar.

Shanxi aged vinegar is a famous traditional Chinese vinegar made from several kinds of cereal by spontaneous solid-state fermentation techniques. In order to get a comprehensive understanding of culturable microorganism's diversity present in its fermentation, the indigenous microorganisms including 47 yeast isolates, 28 lactic acid bacteria isolates and 58 acetic acid bacteria isolates were recovered in different fermenting time and characterized based on a combination of phenotypic and genotypic approaches including inter-delta/PCR, PCR-RFLP, ERIC/PCR analysis, as well as 16S rRNA and 26S rRNA partial gene sequencing. In the alcoholic fermentation, the dominant yeast species Saccharomyces (S.) cerevisiae (96%) exhibited low phenotypic and genotypic diversity among the isolates, while Lactobacillus (Lb.) fermentum together with Lb. plantarum, Lb. buchneri, Lb. casei, Pediococcus (P.) acidilactici, P. pentosaceus and Weissella confusa were predominated in the bacterial population at the same stage. Acetobacter (A.) pasteurianus showing great variety both in genotypic and phenotypic tests was the dominant species (76%) in the acetic acid fermentation stage, while the other acetic acid bacteria species including A. senegalensis, A. indonesiensis, A. malorum and A. orientalis, as well as Gluconobacter (G.) oxydans were detected at initial point of alcoholic and acetic acid fermentation stage respectively.

Effect of travel restrictions, contact tracing and vaccination on control of emerging infectious diseases: transmission of COVID-19 as a case study.

Patch models can better reflect the impact of spatial heterogeneity and population mobility on disease transmission. While, there is relatively little work on using patch models to study the role of travel restrictions, contact tracing and vaccination in COVID-19 epidemic. In this paper, based on COVID-19 epidemic propagation and diffusion mechanism, we establish a dynamic model of disease spread among two patches in which Wuhan is regarded as one patch and the rest of Mainland China (outside Wuhan) as the other patch. The existence of the final size is proved theoretically and some model parameters are estimated by using the reported confirmed cases. The results show that travel restrictions greatly reduce the number of confirmed cases in Mainland China, and the earlier enforced, the fewer confirmed cases. However, it is impossible to bring the COVID-19 epidemic under control and lift travel restrictions on April 8, 2020 by imposing travel restrictions alone, the same is true for contact tracing. While, the disease can always be controlled if the protection rate of herd immunity is high enough and the corresponding critical threshold is given. Therefore, in order to quickly control the spread of the emerging infectious disease (such as COVID-19), it is necessary to combine a variety of control measures and develop vaccines and therapeutic drugs as soon as possible.

[Effect of Epstein-Barr virus-encoded latent membrane protein 1 on ß-catenin transcriptional activity and expression in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the contribution of latent membrane protein (LMP)1 to nasopharyngeal carcinogenesis via Wnt/ß-catenin signal pathway. METHODS: The recombinant plasmid pHA2-LMP1 was constructed; immunofluorescence staining, Dual-Luciferase Reporter Assay, Western blot and immunohistochemistry staining were used to study the effect of LMP1 on the transcriptional activity and expression of ß-catenin. RESULTS: (1) Abnormal expression of ß-catenin was obtained in 38 cases (50.7%, 38/75), LMP1 expression was obtained in 38 cases (50.7%, 38/75). There was significantly positive correlation between LMP1 expression and abnormal expression of ß-catenin in nasopharyngeal carcinoma tissue (P = 0.008). (2) The expression of ß-catenin in nuclei of NPC cell line CNE1 and CNE2 transfected with pHA2-LMP1 plasmid dramatically increased, and the expression was remarkable in poorly-differentiated NPC cell line CNE2 than that of well-differentiated CNE1 cells. (3) LMP1 expression dramatically increased the transcriptional activity of ß-catenin in CNE1 and CNE2 cells transfected with pHA2-LMP1 and was in a time-dependent. The transcriptional activity of ß-catenin was higher in poorly-defferentiated cell line CNE2 than that of well-differentiated NPC cell line CNE1. (4) LMP1 expression did not affect the total protein expression level of ß-catenin in both CNE1 and CNE2 cell lines. CONCLUSION: EB virus-encoded LMP1 may be involved in the pathogenesis of NPC via ß-catenin signal pathway.

Structural identification of 4-benzyl-voglibose hydrochloride monohydrate using NMR and single-crystal X-ray diffraction methods.

The chemical structure studies on an important related substance of voglibose have been carried out using NMR spectroscopy and single crystal X-ray crystallography. For the structure identification study, hydrochloride monohydrate of this compound was isolated and purified. Its molecular structure was characterized and analyzed using 1D (1H NMR, 13C NMR, and DEPT) and 2D (1H,1H-COSY, HSQC, HMBC, TOCSY, and ROESY) NMR spectra. The signal crystal structure was detected by X-ray crystallography. All results indicated this related substance of voglibose was C17H27NO7·HCl·H2O, 5,6-dideoxy-4-benzyl-5-{[2-hydroxy-1-(hydroxymethyl)ethy]amino}-1-C-(hydroxymethyl)-D-epi-inositol hydrochloride monohydrate.

Cell-specific expression and immunolocalization of nitric oxide synthase isoforms and soluble guanylyl cyclase α1 and ß1 subunits in the ovary of fetal, neonatal and immature pigs.

The present study is designed to investigate the cellular expression and immunolocalization of three different nitric oxide synthase (NOS) isoforms and soluble guanylyl cyclase (sGC) subunits in the porcine ovary. Our results showed that in the fetal and neonatal pigs, all three isoforms of NOS were mainly localized in the oocyte and showed the expression of gradual increase in the granulosa cell and theca cell with the growing follicle. In addition, subunits of the sGC, sGC α1 and ß1 were mainly expressed in the granulosa cell in precious studies. The bioactivity of total NOS, eNOS, iNOS and nNOS was detected in the ovary and were higher at prenatal stages compared to postnatal stages. However, the activities of nNOS were no different between prenatal stages and postnatal stages. Taken together, our findings suggested that the NOS/sGC pathway may be involved in the follicular formation and development in the porcine ovary.

Clinicopathological features of gastric glomus tumor.

AIM: To study the clinicopathological features of gastric glomus tumor and review the related Chinese literature published in 1990-2010. METHODS: A case of gastric glomus tumor was reported. Clinicopathological findings in 56 cases of gastric glomus tumor were analyzed. RESULTS: Gastric glomus tumor was far more common in women than in men with a female to male ratio of 1.6:1. The median age of the patients was 45 years (range 28-79 years). The patients often complained of epigastric pain and bloody stool. The tumor was located in antrum of the stomach. The greatest diameter of the tumor was 0.8-11 cm. Histologically, the tumor was comprised of nests of glomus cells surrounding the capillaries. Glomus cells were small, uniform and round. Vimentin, smooth muscle actin and actin were expressed in the tumor. Other markers, including S-100 protein, CD34, CD117, desmin, CD56, synaptophysin, chromogranin A, neuron specific enolase and cytokeratin were all negative. CONCLUSION: Gastric glomus tumor is a rare benign mesenchymal neoplasm. Its diagnosis depends on pathologic examination. Differential diagnosis includes gastrointestinal stromal tumor, paraganglioma and carcinoid tumor.

Morphologic observation and classification criteria of atretic follicles in guinea pigs.

There is a lack of appropriate classification criteria for the determination of atretic follicles in guinea pigs. In the present study, new criteria were established based on the latest morphologic criteria for cell death proposed by the Nomenclature Committee on Cell Death (NCCD) in 2009. Ovaries of guinea pigs were sampled on different stages of estrous cycle, and the morphologic observations of atretic follicles were investigated in serial sections. The results showed that the process of follicular atresia could be classified into four continuous stages: (1) the granulosa layer became loose, and some apoptotic bodies began to appear; (2) the granulosa cells were massively eliminated; (3) the theca interna cells differentiated; and (4) the residual follicular cells degenerated. In addition, the examination revealed that these morphologic criteria were accurate and feasible. In conclusion, this study provides new criteria for the classification of atretic follicles in guinea pigs, and this knowledge can inform future research in the area.

Assay for uric acid level in rat striatum by a reagentless biosensor based on functionalized multi-wall carbon nanotubes with tin oxide.

A novel reagentless amperometric uric acid biosensor based on functionalized multi-wall carbon nanotubes (MWCNTs) with tin oxide (SnO2) nanoparticles has been developed. This was successfully applied to assay uric acid levels from an in vivo microdialysis sampling. Compared with unfunctionalized or traditional carboxylic acid (-COOH)-functionalized MWCNTs, the MWCNTs-SnO2 electrode exhibited higher electrocatalytic oxidation to uric acid. Here, MWCNTs-SnO2 may act as an efficient promoter, and the system exhibited a linear dependence on the uric acid concentration over the range from 1.0 x 10(-7) to 5.0 x 10(-4) mol L(-1). In addition, there was little ascorbic acid interference. The high sensitivity of the MWCNTs-SnO2 modified enzyme electrode enabled the monitoring of trace levels of uric acid in dialysate samples in rat striatum.

Simultaneous assay of glucose, lactate, L-glutamate and hypoxanthine levels in a rat striatum using enzyme electrodes based on neutral red-doped silica nanoparticles.

An electrochemical method suitable for the simultaneous measurement of cerebral glucose, lactate, L-glutamate and hypoxanthine concentrations from in vivo microdialysis sampling has been successfully performed for the first time using a neutral red-doped silica (NRDS) nanoparticle-derived enzyme sensor system. These uniform NRDS nanoparticles (about 50 +/- 3 nm) were prepared by a water-in-oil (W/O) microemulsion method, and characterized by a TEM technique. The neutral red-doped interior maintained its high electron-activity, while the exterior nano-silica surface prevented the mediator from leaching out into the aqueous solution, and showed high biocompability. These nanoparticles were then mixing with the glucose oxidase (GOD), lactate oxidase (LOD), L-glutamate oxidase (L-GLOD) or xanthine oxidase (XOD), and immobilized on four glassy carbon electrodes, respectively. A thin Nafion film was coated on the enzyme layer to prevent interference from molecules such as ascorbic acid and uric acid in the dialysate. The high sensitivity of the NRDS modified enzyme electrode system enables the simultaneous monitoring of trace levels of glucose, L-glutamate, lactate and hypoxanthine in diluted dialysate samples from a rat striatum.