[Epidemiological characteristics of COVID-19 epidemic in Ejina banner, Inner Mongolia Autonomous Region, October 2021]

Objective: To understand the epidemiological characteristics of COVID-19 epidemic in Ejina banner, Inner Mongolia, in October 2021 and provide evidence for the improvement of COVID-19 prevention and control. Methods: The information about the time, area and population distributions of COVID-19 cases in Ejina before November 13, 2021 and the gene sequencing result of the isolates were collected for a statistical descriptive analysis. Results: The first COVID-19 case in Ejina occurred on 7 October, 2021. A total of 164 COVID-19 cases were reported from October 19 to November 12. Most cases were distributed in 6 communities in Darahub (156 cases, 95.12%). The result of full gene sequencing of the isolates indicted that the pathogen was Delta variant (B.1.617.2). The male to female ratio of the cases was 1.3∶1. The age of cases ranged from 1 to 85 years, and the cases aged 20-59 years accounted for 78.66%. The main clinical symptoms were sore throat (91 cases, 91.92%), cough (49 cases, 49.49%) and fever (23 cases, 23.23%). Most cases were ordinary ones (81 cases, 49.39%) and mild ones (68 cases, 41.46%). The cases were mainly detected at the isolation points (84 cases, 51.22%) and through population based nucleic acid testing (62 cases, 37.80%). The basic reproduction number (R₀) of COVID-19 was 5.3, the average incubation period was 3.9 days. The local government rapidly started Ⅳ level emergency response and conducted 10 rounds of nucleic acid tests. The transferring of travelers reduced the risk for the further spread of COVID-19 in Ejina. Conclusions: The epidemic of COVID-19 in Ejina characterized by strong transmission, short incubation period, herd susceptibility and case clustering. Delta variant (B.1.617.2) was the pathogen, which might be imported from Zeke port. Comprehensive prevention and control measures, such as closed-loop management and vaccination, should be continued. The successful transferring of the patients and travelers provided evidence for the effective and precise prevention and control of COVID-19 in a routine manner.

β-Cyclodextrin-based supramolecular nanoparticles: pH-sensitive nanocarriers for the sustained release of anti-tumor drugs

CSL-loaded SBE7-β-CD/HDBAC nanoparticles present pH-trigger controlled release properties, which may enhence the therapeutic effects of the anti-tumor compound CSL.

Experimental and molecular docking investigation of the inclusion complexes between 20(S)-protopanaxatriol and four modified β-cyclodextrins

20(S)-Protopanaxatriol (PPT) is a type of ginsenoside isolated from panax notoginseng or ginseng, which is an essential ingredient in functional food, healthcare products and traditional medicine. However, the research and development of PPT are restricted due to its poor solubility. To circumvent the associated problems, a novel bridged-bis [6-(2,2'-(ethylenedioxy) bis (ethylamine))-6-deoxy-β-CD] (H4) was successfully synthesized. The four inclusion complexes of the mono-[6-(1,4-butanediamine)-6-deoxy-β-CD] (H1), mono-[6-(2,2'-(ethylenedioxy) bis (ethylamine)-6-deoxy-β-CD] (H2) and their corresponding bridged bis(β-CD)s (H3, H4) with PPT were prepared and studied by UV, ¹H NMR, 2D ROESY, FT-IR, XRD and SEM technology. The UV-spectrometric titration showed that H1-4 and PPT formed 1:1 inclusion complexes and the binding constants were 297.61, 322.25, 937.88 and 1742 M^-1, respectively. It was further revealed that the size/shape-matching relationship, hydrophobic interactions and hydrogen bond interactions play the crucial role in determining the stability of H1-4/PPT inclusion complexes. The solubility of PPT was evidently enhanced by193, 265, 453 and 593 times after the formation of inclusion complexes with H1-4, respectively. Furthermore, molecular docking was used to verify the inclusion mode of H4/PPT inclusion complex and also to investigate the stability of H4/PPT in water phase. The molecular simulation results agreed well with the experimental results. This research provides an effective way to obtain novel PPT-based functional food and healthcare products.

Solubility and biological activity enhancement of docetaxel via formation of inclusion complexes with three alkylenediamine-modified β-cyclodextrins

Docetaxel (DTX) is an effective and commonly used chemotherapeutic drug for cancer. However, its efficacy is greatly compromised because of its toxicity and poor water solubility. In order to overcome these disadvantages, three inclusion complexes between DTX and alkylenediamine-modified β-cyclodextrins (H1-3) with ethylene, propylene and butylene segments were prepared and characterized. The phase solubility studies demonstrated that the stoichiometry of the inclusion complexes between H1-3 and DTX were 1 : 1. The binding abilities of host H1-3 towards DTX decrease in the following order: H3 > H2 > H1, which had good consistency with the decreasing alkylene lengths of these hosts. The water solubility of DTX is remarkably increased 216, 242 and 253 times after forming inclusion complexes with H1-3, respectively. In vitro release studies of DTX from H1-3/DTX into NaAc-HAc buffer solution (pH 5.0) or PBS (pH 7.4) exhibited a preliminary stage burst effect and followed by a slow drug release. The cytotoxicity studies revealed that the H1-3/DTX inclusion complexes exhibited better cytotoxicity profiles against MCF-7, SW480 and A-549 cells than that of DTX. Furthermore, compared with the treatment of DTX, the H1/DTX inclusion complex significantly increased the cell apoptosis percentage from 17.2% to 30.2% (5 μg mL-1), 19.0% to 31.0% (10 μg mL-1), and 19.3% to 32.2% (15 μg mL-1), respectively. These results will provide useful information for H1-3/DTX inclusion complexes as safe and efficient anticancer drug formulations.

Host-Guest Inclusion Systems of Morin Hydrate and Quercetin with Two Bis(β-cyclodextrin)s: Preparation, Characterization, and Antioxidant Activity

The inclusion complexation behaviour of morin hydrate (MH) and quercetin (QCT) with the two amide-bridged bis(β-cyclodextrin (β-CD))s, 1 and 2, was investigated in both solution and the solid state. The inclusion complexations were characterised by proton nuclear magnetic resonance, 2D rotating-frame Overhauser effect spectroscopy, X-ray powder diffraction, infrared spectroscopy and scanning electron microscopy. Ultraviolet titration analysis indicated that 1 and 2 form 1:1 molar stoichiometry inclusion complexes with MH and QCT, and the data obtained showed that 2 with two guests has a higher complex stability constant (KS) when compared with that of 1. Moreover, 1 and 2 were able to solubilize MH and QCT to high levels, up to ~200-fold. Furthermore, the antioxidant activity of MH, QCT and their inclusion compounds were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. Together, these results showed that the inclusion complexes exhibited a more effective antioxidant activity when compared with free MH. The satisfactory antioxidant activity and high water solubility of the bis(β-CD)s/flavonoid complexes may have potential use as healthcare products and herbal medicine.

Crystal structure of 4-acetamidobenzoic acid monohydrate

In the title compound, C₉H₉NO₃·H₂O, the plane of the acetamide group is oriented at 20.52 (8)° with respect to the benzene ring, whereas the plane of the carb­oxy­lic acid group is essentially coplanar with the benzene ring [maximum deviation = 0.033 (1) Å]. In the crystal, classical O—H⋯O and N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds link the organic mol­ecules and water mol­ecules of crystallization into a three-dimensional supra­molecular architecture.

N-(7-Dibromo-methyl-5-methyl-1,8-naphthyridin-2-yl)acetamide-pyrrolidine-2,5-dione (1/1)

In the title co-crystal, C₁₂H₁₁Br₂N₃O·C₄H₅NO₂, the naphthyridine derivative and the pyrrolidine-2,5-dione mol­ecules have crystallographic mirror-plane symmetry with all non-H atoms, except the Br atom, located on the mirror plane. In the crystal, N—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into heterodimers. These dimers are further linked into a one-dimensional structure along [010] by weak C—Br⋯O inter­actions [Br⋯O = 3.028 (5) Å and C—Br⋯O = 158.52 (4)°].

Cu(I) and Pb(II) complexes containing new tris(7-naphthyridyl)methane derivatives: synthesis, structures, spectroscopy and geometric conversion

Two novel facial-capping tris-naphthyridyl compounds, 2-chloro-5-methyl-7-((2,4-dimethyl-1,8-naphthyridin-7(1H)-ylidene)(2,4-dimethyl-1,8-naphthyridin-7-yl))methyl-1,8-naphthyridine (L(1)) and 2-chloro-7-((2-methyl-1,8-naphthyridin-7(1H)-ylidene)(2-methyl-1,8-naphthyridin-7-yl))methyl-1,8-naphthyridine (L(2)), as well as their Cu(i) and Pb(ii) complexes, [CuL(a)(PPh(3))]BF(4) (1) (PPh(3) = triphenylphosphine, L(a) = bis(2,4-dimethyl-1,8-naphthyridin-7-yl)(2-chloro-5-methyl-1,8-naphthyridin-7-yl)methane), [CuL(b)(PPh(3))]BF(4) (2) (L(b) = bis(2-methyl-1,8-naphthyridin-7-yl)(2-chloro-1,8-naphthyridin-7-yl)methane), [Pb(OL(a))(NO(3))(2)] (3) (OL(a) = bis(2,4-dimethyl-1,8-naphthyridin-7-yl)(2-chloro-5-methyl-1,8-naphthyridin-7-yl)methanol) and [Pb(L(b))(2)][Pb(CH(3)OH)(NO(3))(4)] (4), have been synthesized and characterized by X-ray diffraction analysis, MS, NMR and elemental analysis. The structural investigations revealed that the transfer of the H-atom at the central carbon to an adjacent naphthyridine-N atom affords L(1) and L(2) possessing large conjugated architectures, and the central carbon atoms adopt the sp(2) hybridized bonding mode. The reversible hydrogen transfer and a geometric configuration conversion from sp(2) to sp(3) of the central carbon atom were observed when Pb(II) and Cu(I) were coordinated to L(1) or L(2). The molecular energy changes accompanying the hydrogen migration and titration of H(+) to different receptor-N at L(1) were calculated by density functional theory (DFT) at the SCRF-B3LYP/6-311++G(d,p) level in a CH(2)Cl(2) solution, and the observed lowest-energy absorption and emission for L(1) and L(2) can be tentatively assigned to an intramolecular charge transfer (ICT) transition in nature.

[Synthesis and spectra of copper(I) bromide complex with N, N-bis[(diphenylphosphino) methyl]-2-pyridinylamine]

A new ligand N, N-bis[(diphenylphosphino)methyl]-2-pyridinylamine (L) and its luminescent dinuclear copper(I) complex [CuBrL]1 (1) were synthesized and characterized by mass spectrometry, elemental analysis, NMR and electronic spectroscopies. The structure of complex 1 was determined by X-ray crystal analysis to be a dinuclear complex with a pseudo-tetrahedral geometry. The complex 1 crystallizes in a triclinic space group P-1 and has two copper(I ) centers bridged by two halogen ligands to form the dinuclear structure with a four-membered Cu2 Br2 ring. The Cu-Cu distance in complex 1 is 0.306 0 nm which is longer than a sum of Van der Waals radius of two copper( I ) atoms. Therefore there is no substantial interaction between the two copper(I) centers in complex 1. DFT calculations indicate that the electron density of HOMO is distributed mainly over the copper, bromine and phosphorus atoms, while that of LUMO is localized on the ligand. Our work shows that there are two mechanisms to form the the lowest excited state of complex 1, i.e. the metal-to-ligand charge transfer (MLCT) and halogen-to-ligand charge transfer (XLCT).

[Molecular geometries and theoretical electronic spectra of four 1,8-naphthyridine derivatives]

The molecular geometries of four 2,4-dimethyl-7-amino-1,8-naphthyridine derivatives were optimized with B3LYP/6-31G(d) method. The energies of their frontier molecular orbitals and the molecular structures were investigated theoretically. The theoretical electronic spectra were calculated with TD-DFT in gas phase, PCM-TD-B3LYP/6-31 + G(d) and semiempirical ZINDO in CH2 Cl2 solution. The influences of solvent model and calculation methods on the electronic absorption spectra were also probed. The calculated results show that delocalized pi bonds exist in the four 1,8-naphthyridine derivatives, and their energy gaps (deltaE) between HOMO and LUMO are relatively small. The variation in their deltaE values gives a consistent trend with that of their electronic absorption with lambda(max). Theoretical spectra achieved prove that their absorptions are red-shifted when the delocalization of pi electrons is enhanced or the capability to donate electron by a substituted group is increased. The maximum absorption peaks of the four derivatives originate from pi (HOMO) --> pi * (LUMO) transition. The spectra calculated at the PCM-B3LYP/6-31 + G(d) level have little difference from experimental results: the differences in wavelength are 2.6, 10.3, 5.3 and 6.9 nm, whereas those in energies are 0.03, 0.09, 0.04 and 0.08 eV, respectively. The obtained results suggest that electronic spectra calculated by TD-DFT on the bases of geometries optimized with B3LYP/6-31(d) are in agreement with experimental ones, and can account for the different spectroscopic properties of the four 1,8-naphthyridine derivatives.

Purification of natural antikeratin autoantibodies from normal human serum and their effect on human keratinocytes cultured in vitro

BACKGROUND

Antikeratin (AK) autoantibodies, circulating antibodies against epidermal keratins, have been detected in all normal human sera. However, direct evidence on the biological significance of AK autoantibodies is still lacking.

OBJECTIVES

To purify AK autoantibodies from human serum and to make a preliminary study of their biological effects on human keratinocytes.

METHODS

We first extracted keratin polypeptides from human stratum corneum and analysed their purity using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Next, a keratin affinity column was prepared with the extracted keratins, and AK autoantibodies were purified from pooled normal human serum. Antibodies obtained were identified with SDS-PAGE, enzyme-linked immunosorbent assay, immunoperoxidase staining, immunoelectron microscopy and Western blotting. The biological effect of AK autoantibodies on cultured human keratinocytes was studied using a DNA synthesis assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric determination and cell cycle analysis.

RESULTS

On average, 1.83 +/- 0.24 mg of antibodies could be purified from 10 mL of pooled human serum. High-titre IgG (about 1 : 70) and low-titre IgM (about 1 : 30) AK autoantibodies were obtained. The DNA synthesis assay and MTT colorimetric determination demonstrated that AK autoantibodies have a significant dose-dependent inhibitory effect on cultured keratinocytes. Correlation coefficients in the two experiments were - 0.583 and - 0.797, respectively. Cell cycle analysis indicated that a small dose of AK autoantibodies leads to inhibition of proliferation of cultured keratinocytes, whereas a large dose of AK autoantibodies causes a visible hypodiploid peak, suggesting apoptosis of keratinocytes.

CONCLUSIONS

The present research lays a solid foundation for further investigation into the biological significance of natural AK autoantibodies.

[Experimental studies of genistein on the proliferation and apoptosis of human prolactinoma cells cultured in vitro]

AIM

To study the influence of genistein (GST) on the proliferation and apoptosis of cultured human prolactinoma cells.

METHODS

MTT method and 3H-TdR incorporation and cell cycle analysis were used to examine the changes of proliferation and DNA synthesis of human prolactinoma cells under influence of GST and beta-estradiol (E2). Tdt-mediated dUTP nick end labeling (TUNEL) were employed to observe the effect of GST and E2 on the apoptosis of human prolactinoma cells.

RESULTS

In a dose dependent manner, GST of different concentration could significantly inhibit the proliferation of human prolactinoma cells cultured in vitro. GST(10(-5) mol/L) could increase the proportion of cells in G1 phase from 55.3% up to 90.3%. E2 of different concentration could dose-dependently increase the proliferation of human prolactinoma cells. E (10(-5) mol/L) could increase the proportion of cells in G2 phase from 15.6% up to 41.8%. However, a lower suppressive proliferation of cultured human prolactinoma cells was observed with GST and E2 together. GST, not E2, could significantly induce the apoptosis of human prolactinoma cells cultured in vitro.

CONCLUSION

GST inhibits the proliferation, DNA synthesis and cell cycle of cultured human pituitary cells, and induces its apoptosis. E2 decreases partly the effect of GST on the suppression of proliferation, not apoptotic induction, of human prolactinoma cells cultured in vitro.

[The influence of acetylcholine on the proliferation of cultured human pituitary tumour cells]

AIM

To study the influence of acetylcholine on the proliferation, DNA synthesis and cell cycle of cultured human pituitary tumour cells.

METHODS

MTT method, 3H-TdR incorporation and cell cycle analysis were used to examine the changes of proliferation and DNA synthesis of human pituitary tumour cells.

RESULTS

Ach at 10(-7) mol/L - 10(-5) mol/L could decrease the 3H-TdR incorporation and the MTT A value in a dose dependent manner (P < 0.01), and the ratio of G1 phase of pituitary tumour cells increased markedly (P < 0.01). The effect of acetylcholine on the proliferation of cultured human pituitary tumour cells could be inhibited by atropine.

CONCLUSION

Ach inhibited the proliferation, DNA synthesis and cell cycle of cultured human pituitary tumour cells, and the inhibitory effect was mediated by acetylcholine receptor.

Hypoxia-inducible nuclear factors bind to an enhancer element located 3' to the human erythropoietin gene

Human erythropoietin gene expression in liver and kidney is inducible by anemia or hypoxia. DNase I-hypersensitive sites were identified 3' to the human erythropoietin gene in liver nuclei. A 256-base-pair region of 3' flanking sequence was shown by DNase I protection and electrophoretic mobility-shift assays to bind four or more different nuclear factors, at least two of which are induced by anemia in both liver and kidney, and the region functioned as a hypoxia-inducible enhancer in transient expression assays. These results provide insight into the molecular basis for the regulation of gene expression by a fundamental physiologic stimulus, hypoxia.