Repair effect of Schwann cells modified by microgene pSVPoMcat on injured spinal cord in rats

OBJECTIVE: To observe the repair effect of Schwann cells (SCs) modified by microgene pSVPoMcat on injured spinal cord in rats. METHODS: Semi-transection injury at the level of T(8) of spinal cord was made with cutting method on 120 Sprague Dawley (SD) rats. Then 40 rats implanted with SCs modified by microgene pSVPoMcat were taken as Group A, 40 rats implanted with simple SCs as Group B and the other 40 rats were taken as the control group (Group C). The functional recovery of the rats was observed through combined behavioral score (CBS) and cortical somatosensory evoked potential (CSEP), and the expression of the glial fibrillary acidic protein (GFAP) was measured with in situ hybridization and immunocytochemistry. At 3 months after operation, the rats were examined with magnetic resonance image (MRI), and the neurofilaments (NF) of the axons were stained with immunohistochemical method. RESULTS: GFAP expression in Group A was significantly lower than that of the other 2 groups. MRI showed that the spinal signals in the injured area recovered fundamentally in Group A, didn't recover in Group B and malacia focus was found in Group C, which was same as the results of NF staining. Wave amplitudes in incubation periods in Group A and Group B tended to recover. It recovered to the normal level in Group A, which was similar to the results of CBS. CONCLUSIONS: SCs modified by microgene pSVPoMcat can inhibit GFAP expression, improve the growth of the axons and the functional recovery of neurons after spinal cord injury.     

人工假体置换治疗高龄老年人不稳定股骨粗隆间骨折

目的　分析及评价应用人工股骨头置换治疗老年股骨粗隆间不稳定骨折的方法及疗效。方法　应用人工股骨头置换治疗老年股骨粗隆间不稳定骨折 32例 ,男 8例 ,女 2 4例 ,年龄 74～ 92岁 ,平均 82 3岁。骨折类型Evans分类 :ⅢA :11例 ,ⅢB :8例 ,Ⅳ :7例 ,Ⅱ :6例。结果　 32例 30例进行短期随访 ,平均随访时间 6个月 (2～ 12个月 ) ,无 1例病人因手术并发症死亡。入院至手术时间 2～ 7d ,平均 4 5d。手术时间 5 5～ 16 5min (平均 85min)。术中补血 0～ 12 0 0ml (平均 6 0 0ml)无术中休克或死亡。伤口均一期愈合 ,无 1例感染。住院时间 10～ 2 1d (平均 14d) ,2 6例病人髋关节功能满意。结论　应用人工股骨头置换是治疗老年股骨粗隆间不稳定骨折的有效手段 ,但应严格掌握其适应证目的　分析及评价应用人工股骨头置换治疗老年股骨粗隆间不稳定骨折的方法及疗效。方法　应用人工股骨头置换治疗老年股骨粗隆间不稳定骨折 32例 ,男 8例 ,女 2 4例 ,年龄 74～ 92岁 ,平均 82 3岁。骨折类型Evans分类 :ⅢA :11例 ,ⅢB :8例 ,Ⅳ :7例 ,Ⅱ :6例。结果　 32例 30例进行短期随访 ,平均随访时间 6个月 (2～ 12个月 ) ,无 1例病人因手术并发症死亡。入院至手术时间 2～ 7d ,平均 4 5d。手术时间 5 5～ 16 5min (平     

The mouse as a model for the study of penile erection: moving towards a smaller animal

We evaluated erectile haemodynamics in mice and characterized the corpus cavernosum morphologically. Four-month-old male BALB/c mice and Sprague-Dawley rats were used. The following stimulation parameters were tested to achieve maximal erectile responses: voltage, 1-6 V; frequency, 6-24 Hz; pulse width, 1 msec; duration, 1 min (n = 7 per group). In a separate group of mice and rats (n = 10 per group), we measured systemic arterial pressure by use of either a 24-gauge angiocatheter or smaller calibre PE-10 tubing. Cavernous tissues from mice, rats or patients with psychogenic erectile dysfunction were stained for factor VIII, alpha-actin and Masson trichrome. Electrical stimulation of the cavernous nerve in mice produced voltage-dependent erectile responses of up to 5 V, with the highest response at a frequency of 12 Hz. The maximal intracavernous pressure recorded at this stimulation parameter was comparable with that in rats. A PE-10 catheter was more reliable for measuring systemic arterial pressure in mice than was a 24-gauge angiocatheter, and the values recorded were similar between mice and rats. The content of endothelial cells, smooth muscle cells and collagen was similar between mice and rats. However, the cavernous tissue of both animals contained lesser amounts of smooth muscle cells and greater amounts of collagen than that of humans (p < 0.01). These results suggest that the mouse is a useful and technically feasible model for the study of penile erection and has functional and structural properties similar to those of rats.     

Radiofrequence ablation of liver cancers

Primary and secondary malignant liver cancer are some of most common malignant tumors in the world. Chemotherapy and radiotherapy are not very effective against them. Surgical resection has been considered the only potentially curtive option, but the majority of patients are not candidates for resection because of tumor size, location near major intrahepatic blood vessels and bile ducts, precluding a margin-negative resection, cirrhotic, hepatitis virus infection or multifocial. Radiofrequence ablation (RFA), which is a new evolving effective and minimally invasive technique, can produce coagulative necrosis of malignant tumors. RFA should be used percutaneously, laparascopically, or during the open laparotomy under the guidance of ultrasound, CT scan and MRI. RFA has lots of advantages superior to other local therapies including lower complications, reduced costs and hospital stays, and the possibility of repeated treatment. In general, RFA is a safe, effective treatment for unresectable malignant liver tumors less than 7.0 cm in diameter. We review the principle, mechanism, procedures and experience with RFA for treating malignant liver tumors.     

A new oxygen-rich energetic salt dihydrazine tetranitroethide: a promising explosive alternative with high density and good performance

A novel high-energy salt with good oxygen balance, dihydrazine tetranitroethide (5), has been synthesized and characterized by FT-IR spectroscopy, NMR spectroscopy, elemental analysis, and X-ray single crystal diffraction. Compound 5 exhibits high crystal density (1.81 g cm⁻³) and impressive detonation velocity (9508 m s⁻¹) and detonation pressure (37.9 GPa), showing potential applications as a high performance explosive and a promising additive of propellants.

A novel high-energy salt with good oxygen balance, dihydrazine tetranitroethide (5), has been synthesized and characterized by FT-IR spectroscopy, NMR spectroscopy, elemental analysis, and X-ray single crystal diffraction.

For applications in propellants, explosives and pyrotechnics, new energetic materials are required with high energy, insensitivity, high thermal stability and environment-friendly decomposition gases.¹ To achieve these goals, chemists have adopted a variety of strategies, such as construction of nitrogen-rich compounds,² energetic salts,³ metal organic framework (MOFs)⁴ and cage structure molecules.⁵ Oxygen balance (OB) is an important parameter to weigh the detonation performance of the nitrogen-rich compounds. Generally explosives may exhibit good performance when the OB close to zero.⁶ One conventional method of increasing the OB of energy materials is to introduce nitro groups, a typical high-energy and oxygen-rich substituent.⁷ Recently, gem-nitro and poly-nitro fragments, such as dinitromethyl,⁸ trinitroethyl⁹ and trinitromethyl,¹⁰ have been of interest to researchers. The compounds consisting of poly-nitro groups exhibit good OB, which largely improves their detonation velocities and pressures.¹¹ In our recent study,¹² we considered using tetranitroethylene instead of nitro as a pre-packaged module, linked to insensitive backbones, just like building blocks. The tetranitroethylene fragment has a high nitrogen content, a positive OB, and high energy within the molecule.¹³ The molecules consisting of the tetranitroethylene fragment are expected to be excellent energetic materials with superior properties.¹² But tetranitroethylene is an unstable intermediate, which is difficult to isolate.¹⁴ Hexnitroethane,¹⁵ a stable tetranitroethylene derivative, can be effectively used to synthetize poly-nitro bridged compound (Scheme 1). Previously, we discussed the possibility of constructing poly-nitro bridged-ring compounds with nitrogen-containing heterocycles and tetranitroethylene by using the Diels–Alder reaction.^12,16Open in a separate windowScheme 1Synthetic pathway for poly-nitro bridged compound.¹⁴Dipotassium tetranitroethide,¹⁷ another tetranitroethylene derivative, lead another thought to synthesize high energy salts with the tetranitroethane anion. The salt-based energetic materials often exhibit lower vapour pressure and higher densities than the non-ionic energetic materials.^3c In addition, the energetic salt can improve the properties by selecting different constituent ions.¹⁸ Based on the advantages of high-energy salt, we chose tetranitroethane anion and hydrazine cation to construct energetic salt by considering both energy and sensitivity. The synthetic route can be seen in Scheme 2. The good OB and large amounts of hydrogen-bonds prompt the target compound (dihydrazine tetranitroethide, 5) with suitable sensitivity and good performance. 5 possesses a crystal density of 1.81 g cm⁻³, detonation velocity of 9508 m s⁻¹ and detonation pressure of 37.9 GPa, which are higher than those of RDX. In addition, the salt-formation improves the carcinogenic and high toxic properties of hydrazine.Open in a separate windowScheme 2The route to synthesis of 5.The intermediate dipotassium tetranitroethide (3) was prepared from tetraiodoethylene (1) after two nitrification reactions, according to literature.¹⁹ The suspension of 3 in dichloromethane dissolves in concentrated sulfuric acid to give the solution of tetranitroethane (4) in dichloromethane. Treatment of the solution of 4 with hydrazine hydrate resulted in dihydrazine tetranitroethide (5), a yellow solid precipitated, that was confirmed by single crystal X-ray diffraction. Single crystal 5 is crystallized by using the method of the evaporation of water.Tetranitroethane 4 is also an unstable compound that is soluble in dichloromethane and difficult to isolate. It decomposed and released a brown gas as the solvent removed. Thus, we analysed the UV spectrum of the solution of 4, instead of the pure compound 4. Compared with the experimental and calculated UV spectrum of solution 4 (Fig. 1), we find that the maximum absorption wavelengths of the two curves match well, 240 nm (tested) and 239.5 nm (calculated). It can be inferred that compound 4 would be tetranitroethane.Open in a separate windowFig. 1The UV spectrum curve of tetranitroethane 4.Dihydrazine tetranitroethide 5 in the monoclinic space group C2/c with a good density of 1.81 g cm⁻³ (298 K). The gem-dinitro group is nearly planar, with the torsion angle of O5–N3–C2–N4, 179.52(17)°. However, the torsion angle of N3–C2–C2′–N4′ and N4–C2–C2′–N3′ are 77.57 (255)° and 77.57 (255)°, respectively, which shows the twist of adjacent dinitromethyl groups is caused by the steric effect. The strong hydrogen-bond interactions are presented between ammonium and nitro groups (Fig. 2b). The details of donor–acceptor distance are given in the ESI.^† Many studies have shown that the hydrogen-bonds enhance the stability of energetic molecules. At the molecular level, intermolecular hydrogen bonds between hydrazine cation and nitro groups play an important role in stabilizing energetic compounds. This kind of hydrogen-bonding interaction and cation–anion contact in the energetic salt is suggested as part of the explanation for closer packing, which causes the good density. As seen in Fig. 2c, the tetranitroethide anions are found in cross-stacking arrangements and layer by layer. While the hydrazine cation in the crystal, as the adhesive between the bricks, help to create a better stacking arrangement.Open in a separate windowFig. 2(a) Molecular structure of 5; (b) hydrogen-bonding interactions of 5 between hydrazine cation and tetranitroethide anion; (c) packing diagram of 5 (unit cell viewed along the b axis).The physical properties and calculated detonation performances are summarized in 20 Compound 5 has a detonation velocity of 9508 m s⁻¹ and a detonation pressure of P: 37.9 GPa, which is better than RDX (8748 m s⁻¹; 34.9 GPa) and similar to HMX (9320 m s⁻¹; 39.5 GPa). The sensitivities to impact and friction are 1.25 J and 34 N, respectively.Physical properties of dihydrazine tetranitroethide 5 and comparison with ADN, RDX and HMX

Foot care knowledge,attitudes and practices among patients with diabetic foot and amputation in St. Kitts and Nevis

About one‐third of admissions to the surgical unit annually are diabetes foot infections in need of amputation In St. Kitts and Nevis. However, the risk factors related to diabetes foot and amputation remain unknown. This study investigated factors associated with diabetic foot and amputation (DFA). Retrospective case control study design, and purposive and quota sampling method was used to recruit the participants. Patients with and without DFA were interviewed at two main hospitals, several primary health centres, and a private doctor's office during July and August 2018. Self‐development questionnaires were applied to assess patients' demographic, physical and behaviour, foot care knowledge, attitudes, and practices related to DFA. Chi‐square, t‐test, and multiple logistic regressions were used to analyse the data. A total of 210 patients were evaluated, 89 had DFA, while 121 did not, with a mean age of 61.10 (SD = 11.85). Participants' responses indicated good knowledge, favourable attitudes, and adequate practices related to foot care. The two items of the questionnaire, ways to maintain blood flow in the lower extremities and wash their feet daily, had significant lower score in DFA group. In multiple logistic regression, knowledge, attitudes, and practices related to foot care were not a significant predictor of DFA. Being male was a predictor of DFA than female (OR = 3.53; 95% CI = 1.65‐7.57; P < .01). Participants who were currently unemployed were less likely to have DFA than those who were employed (OR = 0.38; 95% Cl = 0.17‐0.86; P < .05). Comparing patients with the longest experience of diabetes mellitus (31 years or more) with those who had diabetes for the shortest period of time (between 1 and 10 years) was less likely to have DFA (OR = 0.38; 95% CI = 0.15‐0.97; P = <.05). The combination of these independent variables could explain 29% of the variance in DFA. Based on these findings, strategies to prevent diabetic foot and amputation should focus on male and outdoor heavy worker, and longer duration of diabetes patients which are identified in this study.