Mutant polycystin-2 induces proliferation in primary rat tubular epithelial cells in a STAT-1/p21-independent fashion accompanied instead by alterations in expression of p57KIP2 and Cdk2

Background

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is characterized by the formation of multiple fluid-filled cysts that destroy the kidney architecture resulting in end-stage renal failure. Mutations in genes PKD1 and PKD2 account for nearly all cases of ADPKD. Increased cell proliferation is one of the key features of the disease. Several studies indicated that polycystin-1 regulates cellular proliferation through various signaling pathways, but little is known about the role played by polycystin-2, the product of PKD2. Recently, it was reported that as with polycystin-1, polycystin-2 can act as a negative regulator of cell growth by modulating the levels of the cyclin-dependent kinase inhibitor, p21 and the activity of the cyclin-dependent kinase 2, Cdk2.

Methods

Here we utilized different kidney cell-lines expressing wild-type and mutant PKD2 as well as primary tubular epithelial cells isolated from a PKD transgenic rat to further explore the contribution of the p21/Cdk2 pathway in ADPKD proliferation.

Results

Surprisingly, over-expression of wild-type PKD2 in renal cell lines failed to inactivate Cdk2 and consequently had no effect on cell proliferation. On the other hand, expression of mutated PKD2 augmented proliferation only in the primary tubular epithelial cells of a rat model but this was independent of the STAT-1/p21 pathway. On the contrary, multiple approaches revealed unequivocally that expression of the cyclin-dependent kinase inhibitor, p57^KIP2, is downregulated, while p21 remains unchanged. This p57 reduction is accompanied by an increase in Cdk2 levels.

Conclusion

Our results indicate the probable involvement of p57^KIP2 on epithelial cell proliferation in ADPKD implicating a new mechanism for mutant polycystin-2 induced proliferation. Most importantly, contrary to previous studies, abnormal proliferation in cells expressing mutant polycystin-2 appears to be independent of STAT-1/p21.     

Early and multiple origins of metastatic lineages within primary tumors

Many aspects of the evolutionary process of tumorigenesis that are fundamental to cancer biology and targeted treatment have been challenging to reveal, such as the divergence times and genetic clonality of metastatic lineages. To address these challenges, we performed tumor phylogenetics using molecular evolutionary models, reconstructed ancestral states of somatic mutations, and inferred cancer chronograms to yield three conclusions. First, in contrast to a linear model of cancer progression, metastases can originate from divergent lineages within primary tumors. Evolved genetic changes in cancer lineages likely affect only the proclivity toward metastasis. Single genetic changes are unlikely to be necessary or sufficient for metastasis. Second, metastatic lineages can arise early in tumor development, sometimes long before diagnosis. The early genetic divergence of some metastatic lineages directs attention toward research on driver genes that are mutated early in cancer evolution. Last, the temporal order of occurrence of driver mutations can be inferred from phylogenetic analysis of cancer chronograms, guiding development of targeted therapeutics effective against primary tumors and metastases.It has long been understood that tumorigenesis is an evolutionary process (1) associated with the accumulation of somatic mutations (2). However, many aspects of that process that are fundamental to cancer biology and targeted treatment have been challenging to reveal, such as the divergence times and genetic clonality of metastatic lineages (3, 4). Somatic mutations have revealed tumor type-specific drivers by comparison of primary tumor and normal tissues (5, 6), and studies examining the evolutionary process of cancer across multiple sites have used a handful of subjects to identify ubiquitous, shared, and private mutations (1) and to reconstruct a number of tumor phylogenies using parsimony or unweighted pair group methods with arithmetic mean (1, 7) but have lacked the power to generalize about the tumorigenic or metastatic process across cancer types (1).Tumor phylogenetics, using a larger sample with explicit evolutionary models, can be applied using molecular evolutionary models to reconstruct ancestral states of somatic mutations and infer cancer chronograms, revealing novel information about the timing of gene mutations and their contributions to tumorigenesis and metastasis and addressing three fundamental aspects of cancer biology. First, the topology of divergence of primary and metastatic lineages can differentiate between a linear model of cancer progression, in which all metastatic tumors are descended from a single original primary cell such that all metastases are more closely related to each other than they are to any tissue in the primary tumor, and a branched model, in which metastases can originate from divergent lineages within primary tumors. Second, molecular evolutionary trees and chronograms can quantify how early metastatic lineages arise in tumor development, clarifying the role of mutations in facilitating metastasis. Last, integration of temporal inferences across patients can convey the order of occurrence of driver mutations, guiding development of targeted therapeutics effective against primary tumors and metastases.Here, we perform tumor phylogenetics to address these questions. Although ascertaining variable degrees of tumor heterogeneity (1) by computational analyses of subclonality within primary tumors has proven challenging (8), another approach to revealing heterogeneity is analysis of the sequence divergence of major clones extracted from distant sites. We replayed the “tape of cancer” and mapped genetic mutations on the tree of cancer evolution extending from normal tissue to primary tumor and metastases. Analyzing new exome sequence data from primary and metastatic sites, we applied maximum likelihood and Bayesian approaches to reveal phylogenetic relationships and tumor evolution chronology. We identified genetic mutations associated with tumorigenesis that commonly precede the first genetic divergence of all cancer lineages, also examining those that precede all metastases. Furthermore, we quantified the temporal distributions of the first genetic divergence of metastases from the primary tumor and evaluated the temporal order of gene mutations in cancer.     

C2A activates a cryptic Ca(2+)-triggered membrane penetration activity within the C2B domain of synaptotagmin I.

Synaptotagmin (syt) I, an integral membrane protein localized to secretory vesicles, is a putative Ca(2+) sensor for exocytosis. Its N terminus spans the membrane once, and its cytoplasmic domain contains two conserved C2 domains, designated C2A and C2B. The isolated C2A domain penetrates membranes in response to Ca(2+); isolated C2B does not. Here, we have addressed the function of each C2 domain, but in the context of the intact cytoplasmic domain (C2A-C2B), by using fluorescent reporters placed in the Ca(2+)-binding loops of either C2A or C2B. Surprisingly, these reporters revealed that, analogous to C2A, a Ca(2+)-binding loop in C2B directly penetrates into lipid bilayers. Penetration of each C2 domain was very rapid (k(on) approximately 10(10) M(-1) x s(-1)) and resulted in high affinity C2A-C2B-liposome complexes (K(d) approximately 13-14 nM). C2B-bilayer penetration strictly depended on the presence, but not the membrane binding activity, of an adjacent C2A domain, severing C2A from C2B after protein synthesis abolished the ability of C2B to dip into bilayers in response to Ca(2+). The activation of C2B by C2A was also displayed by the C2 domains of syt III but not the C2 domains of syt IV. A number of proteins contain more than one C2 domain; the findings reported here suggest these domains may harbor cryptic activities that are not detected when they are studied in isolation.     

Sex Differences in Atrial Fibrillation—Update on Risk Assessment,Treatment, and Long-Term Risk

Purpose of review

Atrial fibrillation (AF) is a growing health problem worldwide. While the disease plagues both men and women, this arrhythmia does not affect both sexes equally. Women are more likely to have major adverse outcomes such as stroke and its sequela; however, recent data on stroke prevention show improving outcomes. The purpose of this review of the recent literature is to summarize important updates on risk scores and management of patients with AF.

Recent findings

It has been well known that women have a higher risk of strokes than men when untreated or when treated with warfarin. Current risk scores emphasizing new risk factors such as the higher risk of strokes in women have been incorporated into clinical guidelines. However, with the use of direct oral anticoagulants, this sex disparity on stroke is no longer seen and women have less major bleeding than men. The use of cardiac glycosides is associated with increased incidence of breast cancer, and this medication is used more in women. Procedural complications for the management of AF are higher in women.

Summary

The study of the pathophysiology of AF and its management is a rapidly evolving area of cardiovascular medicine. Sex-specific data is necessary to achieve advances in the field and improve the outcomes in both men and women.

     

青蒿琥酯分别与诺氟沙星、甲硝唑伍用的体内、外抗恶性疟作用

目的　了解青蒿琥酯分别与诺氟沙星、甲硝唑伍用的体内、外抗疟作用。　方法　采用青蒿琥酯与诺氟沙星 (A组 )或甲硝唑 (B组 )联用 3d疗法治疗无并发症的恶性疟。体外测定采用 Rieckmann体外微量法测定恶性疟原虫对 3种药物单一用药及青蒿琥酯分别与诺氟沙星或甲硝唑联用的敏感性。　结果　体内观察法共收治 70例病人 ,其中 A组 5 5例 ,B组 15例。平均退热时间分别为 (2 6 .5± 16 .5 ) h(8h～ 93h)、(19.2± 11.0 ) h(4h～ 4 1h) ;平均原虫无性体转阴时间分别为 (37.4± 15 .3) h(13h～ 93h)和 (42 .8± 14 .7) h(2 5 h～ 72 h) ;2 8d复燃率分别为 4 7.4 %和 75 .0 %。体外微量法测得青蒿琥酯与诺氟沙星伍用的 ID50 分别为单用组的 5 .9%和 0 .3% ;青蒿琥酯与甲硝唑伍用的 ID50 分别为单用组的38.8%和 5 .6 %。　结论　青蒿琥酯分别与诺氟沙星、甲硝唑伍用在体外对抗青蒿琥酯恶性疟原虫有明显增效作用 ,但在临床治疗中未能提高治愈率     

在外籍留学生中发现一例“窗口期”HIV感染者的调查报告

目的 说明HIV感染从“窗口期”到抗体阳性期演变的过程,为加强HIV监测提供科学依据.方法 HIV首次确认试验出现不明显的HIV蛋白印迹带型而不能确定为HIV感染者,须间隔28天再次复查.结果 HIV首次确认试验出现不明显的HIV蛋白印迹带型2条,经28天后再进行确认试验时,出现清晰的HIV蛋白印迹带型5条,被确认为HIV感染者.结论 这是一例典型的从HIV感染“窗口期”到抗体阳性期演变的HIV感染者.     

Repeated formaldehyde inhalation impaired olfactory function and changed SNAP25 proteins in olfactory bulb

Background:

Formaldehyde inhalation exposure, which can occur through occupational exposure, can lead to sensory irritation, neurotoxicity, mood disorders, and learning and memory impairment. However, its influence on olfactory function is unclear.

Objectives:

To investigate the mechanism and the effect of repeated formaldehyde inhalation exposure on olfactory function.

Methods:

Rats were treated with formaldehyde inhalation (13.5±1.5 ppm, twice 30 minutes/day) for 14 days. Buried food pellet and locomotive activity tests were used to detect olfactory function and locomotion. Western blots were used to evaluate synaptosomal-associated protein 25 (SNAP25) protein levels in the olfactory bulb (OB) lysate and synaptosome, as well as mature and immature olfactory sensory neuron markers, olfactory marker protein (OMP), and Tuj-1. Real-time polymerase chain reaction (PCR) was used to detect SNAP25 mRNA amounts.

Results:

Repeated formaldehyde inhalation exposure impaired olfactory function, whereas locomotive activities were unaffected. SNAP25 protein decreased significantly in the OB, but not in the occipital lobe. SNAP25 also decreased in the OB synaptosome when synaptophysin did not change after formaldehyde treatment. mRNA levels of SNAP25A and SNAP25B were unaffected. Mature and immature olfactory sensory neuron marker, OMP, and Tuj-1, did not change after formaldehyde treatment.

Conclusion:

Repeated formaldehyde exposure impaired olfactory function by disturbing SNAP25 protein in the OB.     

Human Exposure to Live Poultry and Psychological and Behavioral Responses to Influenza A(H7N9), China

To investigate human exposure to live poultry and changes in risk perception and behavior after the April 2013 influenza A(H7N9) outbreak in China, we surveyed 2,504 urban residents in 5 cities and 1,227 rural residents in 4 provinces and found that perceived risk for influenza A(H7N9) was low. The highest rate of exposure to live poultry was reported in Guangzhou, where 47% of those surveyed reported visiting a live poultry market >1 times in the previous year. Most (77%) urban respondents reported that they visited live markets less often after influenza A(H7N9) cases were first identified in China in March 2013, but only 30% supported permanent closure of the markets to control the epidemic. In rural areas, 48% of respondents reported that they raised backyard poultry. Exposure to live commercial and private poultry is common in urban and rural China and remains a potential risk factor for human infection with novel influenza viruses.     

New Hepatitis E Virus Genotype in Camels,the Middle East

In a molecular epidemiology study of hepatitis E virus (HEV) in dromedaries in Dubai, United Arab Emirates, HEV was detected in fecal samples from 3 camels. Complete genome sequencing of 2 strains showed >20% overall nucleotide difference to known HEVs. Comparative genomic and phylogenetic analyses revealed a previously unrecognized HEV genotype.Hepatitis E virus (HEV) belongs to the family Hepeviridae and genus Hepevirus. Among humans worldwide, HEV is the most common cause of acute viral hepatitis. The disease is generally self-limiting, but mortality rates are high among pregnant women and young infants. Chronic HEV infection is a problem for immunocompromised patients, such as those who have received a solid organ transplant and those with HIV infection. In addition to humans, HEV has been found in the other mammals: pigs, boar, deer, rodents, ferrets, rabbits, mongoose, bats, cattle, sheep, foxes, minks, and horses (1–3). Among the 4 known HEV genotypes, HEV1 and HEV2 infect only humans; whereas, HEV3 and HEV4 can infect humans, pigs, and other mammals. Human infections with HEV3 and HEV4 have been associated with consumption of raw or undercooked pork or game meat (4). Traditionally, HEV infection is mainly transmitted through water contaminated with infected feces. Since water supplies and sanitary infrastructures have been improved, animals have become a major source of human HEV infection. We detected HEV in fecal samples from dromedary camels in the Middle East.     

Individualized endovascular treatment of high-grade traumatic vertebral artery injury

Background

Traumatic vertebral artery injury (TVAI) is associated with craniocervical trauma that can lead to potentially fatal posterior circulation stroke. It presents a clinical challenge since it is hard to detect and there are no widely accepted guidelines on diagnosis and management. High-grade TVAI is more difficult to treat and no consensus has been reached yet.

Methods

We performed a single-center, long-term, therapeutic study involving 272 patients with craniocervical injury, eleven of which were diagnosed with high-grade TVAI. Individualized endovascular treatments were performed on these patients based upon the hemodynamic and morphological characteristics of the injured vertebral artery. Postoperative angiography was conducted at 2 weeks, 3 months and 6 months, and then annually after intervention.

Results

Ten vertebral pseudoaneurysms and one arteriovenous fistula (AVF) were confirmed by postoperative angiography. All the participants’ neurological deficit symptoms disappeared or were significantly alleviated gradually, and no new symptoms were found after endovascular treatment. Follow-up angiography of the patients with pseudoaneurysms showed a normally shaped vertebral artery with no stenosis or aneurysms; the angiographic result of the patient with the AVF presented successful embolization in the proximal vertebral artery fistula with no progression or new stenosis. Their modified Rankin Scale (mRS) scores were also satisfactory.

Conclusions

Application of individualized endovascular therapy in high-grade TVAI is safe, technically feasible and clinically effective, but there is no comparison between endovascular management and other management approaches because randomized trials cannot be carried out currently.