HIV Protease: Historical Perspective and Current Research

The retroviral protease of human immunodeficiency virus (HIV) is an excellent target for antiviral inhibitors for treating HIV/AIDS. Despite the efficacy of therapy, current efforts to control the disease are undermined by the growing threat posed by drug resistance. This review covers the historical background of studies on the structure and function of HIV protease, the subsequent development of antiviral inhibitors, and recent studies on drug-resistant protease variants. We highlight the important contributions of Dr. Stephen Oroszlan to fundamental knowledge about the function of the HIV protease and other retroviral proteases. These studies, along with those of his colleagues, laid the foundations for the design of clinical inhibitors of HIV protease. The drug-resistant protease variants also provide an excellent model for investigating the molecular mechanisms and evolution of resistance.     

Reactivation of heat-inactivated Ku proteins by heat shock cognate protein HSC73

Purpose: Mouse double-stranded DNA-dependent protein kinase (DNA-PK) activity is heat sensitive. Recovery of heat-inactivated DNA repair activity is a problem after combination therapy with radiation and heat. We investigated the mechanism of recovery of heat-inactivated DNA-PK activity.

Methods: Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.

Results: The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37?°C after heat treatment at 44?°C for 15?min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3?h of incubation at 37?°C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3?h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.

Conclusions: These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72.     

miR-26b通过调节Notch1信号通路参与原发性肝细胞肝癌侵袭的机制研究

目的:探讨miR-26b参与原发性肝细胞肝癌（HCC）侵袭的机制。方法:在细胞培养液中培养人肝细胞系HL-7702和HCC细胞各系Hepb-3、HuH-7、MHCC97-L、MHCC97-H。实时荧光定量PCR法（qRT-PCR）检测miR-26b的表达水平；用miR-26b mimics、miR-26b inhibitors和Notch1-siRNA分别转染HCC细胞；MTT实验检测转染后HCC细胞的活力；采用Western blot检测Notch1受体蛋白表达水平的变化；Transwell小室测定不同处理后的HCC细胞的侵袭能力。结果:人正常肝细胞系HL-7702和HCC细胞系Hepb-3、HuH-7、MHCC97-L、MHCC97-H中的miR-26b相对表达含量随其侵袭和迁移能力的升高而依次下降；抑制miR-26b的表达，Notch1受体蛋白表达明显增高，而此时HCC细胞的侵袭性显著增强；相反，上调miR-26b的表达，Notch1受体蛋白表达明显降低，而HCC细胞侵袭性显著下降；miR-26b可能通过调控Notch1信号通路调节HCC细胞侵袭性。结论:miR-26b通过负调控Notch1信号通路抑制HCC细胞侵袭能力，为HCC侵袭的机制奠定了理论基础，miR-26b可能成为HCC治疗的新靶点。     

新生血管特异性结合肽GX1二聚体抑制胃癌新生血管生成的实验研究

目的:探讨新生血管特异性结合肽GX1二聚体对胃癌新生血管生成的影响。方法:化学合成GX1二聚体、GX1单体、对照肽二聚体，CCK-8实验、管状结构形成实验、迁移实验研究GX1二聚体对胃癌血管内皮细胞（co-HUVEC）增殖、微管形成、迁移能力的影响，流式细胞学技术分析其对细胞周期分布和凋亡的影响。结果:CCK-8结果显示，GX1二聚体与对照肽二聚体及PBS对照组相比，100~200 μmol/L可抑制co-HUVEC增殖，具有统计学差异（P<0.05），并呈剂量依赖性，GX1二聚体较单体抑制作用增强，并有统计学差异（P<0.05）。管状结构形成实验、细胞损伤迁移实验结果显示，与对照肽二聚体及对照组PBS 相比，GX1二聚体及GX1单体，均可抑制胃癌内皮细胞管状结构的形成及迁移，且二聚体抑制作用强于单体；对照肽二聚体仅有轻微的抑制胃癌内皮细胞管状结构的形成及迁移。流式细胞术分析显示，与对照肽二聚体及PBS对照组相比，GX1二聚体及GX1单体均可诱导细胞凋亡（P<0.05），且GX1二聚体的诱导作用强于GX1单体（P<0.05），而对细胞周期分布则无明显影响。结论:GX1二聚体和GX1单体均可抑制胃癌新生血管内皮细胞增殖、微管形成、迁移能力及诱导凋亡，且GX1二聚体较GX1单体作用增强。GX1二聚体有望代替单体成为胃癌新生血管靶向治疗小肽类药物。     

PTPN6通过抑制SP1/p38 MAPK信号通路促进前列腺癌细胞的化疗敏感性

目的:研究PTPN6对前列腺癌细胞PC3的作用及其作用机制。方法:RT-PCR和Western blot实验检测前列腺癌组织和细胞以及癌旁组织和人前列腺上皮细胞中PTPN6的表达量；CCK-8和EDU染色实验检测PTPN6对前列腺癌细胞PC3增殖的影响；Western blot实验检测耐药相关蛋白P-gp和MRP-1的蛋白表达水平。结果:RT-PCR和Western blot结果显示，PTPN6在前列腺癌组织和细胞中的表达量显著低于癌旁组织和人前列腺上皮细胞中的表达量；过表达PTPN6显著抑制前列腺癌PC3细胞的增殖，并降低PC3细胞的耐药性；进一步的研究结果表明PTPN6可通过抑制SP1，并抑制p38 MAPK通路抑制PC3细胞的增殖和耐药。结论:PTPN6能够抑制前列腺癌细胞PC3的增殖和耐药，提高其化疗敏感性，作用机制是通过调控SP1/p38 MAPK信号通路来实现的，这一结果能够为临床上前列腺癌的诊断和治疗提供分子基础。     

Policy Recommendations Regarding Skilled Nursing Facility Management of Coronavirus 19 (COVID-19): Lessons from New York State

To provide policy recommendations for managing Coronavirus 19 (COVID-19) in skilled nursing facilities, a group of certified medical directors from several facilities in New York state with experience managing the disease used e-mail, phone, and video conferencing to develop consensus recommendations. The resulting document provides recommendations on screening, protection of staff, screening of residents, management of Coronavirus 19 positive and presumed positive cases, communication during an outbreak, management of admissions and readmissions, and providing emotional support for staff. These consensus guidelines have been endorsed by the Executive Board of the New York Medical Directors Association and the Board of the Metropolitan Area Geriatrics Society.     

Attachment to Caregivers and Type 1 Diabetes in Children

Attachment is a behavioral and physiological system, which enables individual’s dynamic adaptation to its environment. Attachment develops in close interaction between an infant and his/her mother, plays an important role in the development of the infant’s brain, and influences the quality of interpersonal relationships throughout life.Security of attachment is believed to influence individual response to stress, exposing insecurely organized individuals to deregulated autonomic nervous system and exaggerated hypothalamic-pituitary-adrenal activity, which, in turn, produces increased and prolonged exposure to stress-hormones. Such stress responses may have considerable implications for the development of diverse health-risk conditions, such as insulin resistance and hyperlipidemia, shown by numerous studies.Although the mechanisms are not yet fully understood, there is compelling evidence highlighting the role of psychological stress in the development of type 1 diabetes (T1D). One of the possible contributing factors for the development of T1D may be the influence of attachment security on individual stress reactivity. Thus, the suggestion is that insecurely attached individuals are more prone to experience increased and prolonged influence of stress hormones and other mechanisms causing pancreatic beta-cell destruction.The present paper opens with a short overview of the field of attachment in children, the principal attachment classifications and their historic development, describes the influence of attachment security on individual stress-reactivity and the role of the latter in the development of T1D. Following is a review of recent literature on the attachment in patients with T1D with a conclusion of a proposed role of attachment organization in the etiology of T1D.     

老年人桡骨远端C型骨折的手术治疗与非手术治疗的疗效对比

目的：探讨老年人桡骨远端C型骨折的手术治疗与非手术治疗的疗效差异，评价两种方法的优缺点。方法回顾性分析2009-12—2011-12收治的老年桡骨远端C型骨折68例，按照治疗方法分为A组(手术组)及B组(非手术组)，统计分析两组患者的临床资料。结果 A组33例， B组35例，平均随访21.5个月。两组患者的年龄、骨折类型均无差异(P＞0.05)；术后影像学指标A组优于B组，骨折愈合时间B组优于A组，治疗成本A组大于B组(P＜0.05)；Cooney评分早期A组优于B组，1年后两组无差异，两组的并发症无差异(P＞0.05)。结论老年人桡骨远端C型骨折手术治疗较非手术治疗可获得更好的复位及早期功能，但远期功能恢复无差异。