[Risk factors of occurrence and treatment failure of peritoneal dialysis-associated polymicrobial peritonitis: a multicenter retrospective study]

OBJECTIVE

To determine the risk factors of occurrence and treatment failure of peritoneal dialysis associatedperitonitis (PDAP) due to polymicrobial infections.

METHODS

We retrospectively collected the clinical data of patients with PDAP from the peritoneal dialysis (PD) centers in 4 general hospitals in Jilin Province from 2013 to 2019. The patients were divided, according to the results of peritoneal dialysate culture, into polymicrobial PDAP group and control group for comparison of the clinical data, treatment outcomes, and long-term prognosis. The independent risk factors of the occurrence and treatment failure of polymicrobial PDAP were explored using multivariate regression analysis.

RESULTS

We recruited a total of 625 patients from the 4 PD centers, among whom 1085 episodes of PDAP were recorded. Polymicrobial PDAP accounted for 7.6% of the total PDAP episodes, and this proportion increased from 5.3% in 2013-2016 to 9.4% in 2017-2019 (P= 0.012). Compared with the control group, polymicrobial PDAP group had higher proportions of elderly patients and patients with refractory PDAP, with greater white blood cell counts in the first-day dialysate and longer course of antibiotic treatment (P < 0.05). The risk of catheter removal and treatment failure (catheter removal or PDAP-related death) in polymicrobial PDAP group was 2.972 times (OR=2.972, 95% CI: 1.634-5.407, P < 0.001) and 2.692 times (OR=2.692, 95% CI: 1.578-4.591, P < 0.001) that in the control group, respectively. The risk of withdrawal from PD (technical failure + all-cause death) was 1.5- fold higher in polymicrobial PDAP group than that in the control group (OR=1.500, 95% CI: 1.085-2.074, P=0.014). Elderly patients (>65 years) had a 1.937-fold higher risk of experiencing polymicrobial PDAP than younger patients (OR=1.937, 95% CI: 1.207-3.109, P= 0.006). Diabetes mellitus (OR=5.554, 95% CI: 1.021-30.201, P=0.047), mixed fungal infeciton (OR=343.687, 95% CI: 21.554- 5480.144, P < 0.001), and Pseudomonas aeruginosa infection (OR=11.518, 95% CI: 1.632 to 81.310, P=0.014) were associated with increased risks of treatment failure by 4.554, 342.687 and 10.518 times, respectively.

CONCLUSION

The proportion of polymicrobial PDAP in the total PDAP cases tends to increase in recent years. Polymicrobial infection is an independent risk factor of both treatment failure and poor prognosis in patients with PDAP. An old age is an independent risk factor for polymicrobial PDAP, while diabetes mellitus and infections with mixed fungi or Pseudomonas aeruginosa are independent risk factors for treatment failure.

[Treatment of lumbar degenerative diseases with recapping laminoplasty and nerve root canal's decompression preserving the continuity of supraspinous ligament]

Objective: To explore the clinical effect of lumbar discectomy and nerve root canal's enlargement preserving the continuity of supraspinous ligament in the treatment of lumbar degenerative disease. Methods: The data of patients with lumbar degenerative disease who underwent operation from 2016 to 2018 were analyzed retrospectively, and the patients were divided into two groups according to the different operation. The treatment group (17 cases) was treated with recapping laminoplasty, lumbar discectomy and nerve root canal's enlargement, and the control group (28 cases) was treated with total laminectomy, nerve root canal's enlargement, lumbar discectomy, interbody fusion and internal fixation (PLIF). All patients were followed up for 12 to 27 months (mean 17.8 months). Japanese Orthopaedic Association Scores(JOA) and visual analogue scale(VAS) of pain were used to evaluate the clinical effect before and after the operation, lumbar dynamical X-ray and Cobb angle were collecting for imaging evaluation, and the adjacent segment degeneration at the last follow-up was recorded. Results: There was no significant difference in preoperative JOA score, VAS score and Lumbar Cobb angle between the two groups (all P>0.05). The operation time in the treatment group was shorter than that in the control group, and the blood loss during operation in the treatment group was lower than that in the control group, the bed rest time of the treatment group after operation was shorter than that in the control group ((79±14) vs (118±17) min, (151±38) vs (324±70) ml and (3.4±0.7) vs (4.3±1.0) d,respectively; t=-8.508, -10.724, -3.244, all P<0.01). In addition, compared with the control group, the volume of postoperative drainage in the treatment group also decreased significantly (t=-5.637, P<0.01). There was no significant difference in JOA score between the two groups 1 year after the operation (P>0.05), but there was significant difference in VAS score between the two groups, the treatment group was better than the control group (P<0.05). Compared with the control group, the lumbar Cobb angle in the treatment group increased significantly one year after the operation (55.3°±3.2° vs 38.4°±6.2°, t=10.391, P<0.05). During the follow-up, no loosening or fracture of the implants was found in all patients. Conclusion: Treatment of lumbar degenerative diseases with recapping laminoplasty and nerve root canal's decompression preserving the continuity of supraspinous ligament by ultrasound osteotome has the same clinical effect as PLIF. It has the advantages of shortening operation time, less bleeding, better maintenance of lumbar lordosis after operation and reduction of adjacent segment degeneration.

[A novel trans-muscular approach for microsurgical bilateral decompression via unilateral approach for degenerative lumbar stenosis: a series study]

Objective: To compare clinical outcomes of microsurgical bilateral decompression via unilateral approach (MBDU) between trans longissimus and iliocostalis approach, a novel lateral paraspinal approach(LPA), and classic Wiltseapproach for single level degenerative lumbar stenosis. Methods: LPA approach was researched by imaging measurement and cadaver anatomy. Retrospective analysis of a total 124 cases(male/female 75/49, aged(55±14) years) received single-level MBDU due to degenerative lumbar stenosis from 2016 to 2018 in Beijing Tiantan Hospital. Patients were categorized into two groups according to spinal canal morphology. Group A: trefoil shape (n=48), received MBDU via LPA; Group B: round & oval shape (n=76), received MBDU via Wiltse approach. Clinical parameters, including visual analogue scale (VAS) of pain, OswestryDability Index (ODI), satisfaction rate were assessed before the operation and at the latest follow-up. The internal fixation and intervertebral fusion were evaluated by X-ray and CT.The data were compared with single sample t test between the two groups. Results: The feasibility of trans longissimus and iliocostalis approach was proved by imaging measurement and anatomic study. The tube's maximum tilt angle in LPA group was 65°, and it was 40°in Wiltse group. There was no significantly difference in the operating time, bleeding and drainage volume between the two groups((120±27) min vs (115±32) min, (104±31) ml vs (110±41) ml, (50±15) ml vs (47±18) ml, respectively, t=1.246,-1.917,1.730,all P>0.05). In both groups, VAS and ODI scores significantly improved at the latest follow-up when compared with those before the operation (all P<0.05), but those were all comparable between the two groups(all P>0.05). The excellent rate of subjective satisfaction for the clinical efficacy in group A and B was 89.6%(43/48) and 86.8%(66/76) respectively (χ(2)=0.208,P>0.05). Conclusions: LPA approachfor microsurgical bilateral decompression via unilateral approach (MBDU) in degenerative lumbar stenosis is safe and effective, it has advantages in direct vison of contralateral nerve root canal decompression for trefoil shaped spinal canal.

Single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle: a novel technique for pediatric inguinal hernia

PURPOSE

Laparoscopic high ligation of the internal inguinal ring is an alternative procedure for treatment of pediatric inguinal hernia (PIH), with a major trend toward increasing use of extracorporeal knotting and decreasing use of working ports. We have utilized this laparoscopic technique to treat the entire spectrum of PIH (including incarcerated cases) for more than 17 years, and the technique continues to evolve and improve. We herein report our latest modification of this minimally invasive technique, namely single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle, and evaluate its safety and efficacy.

METHODS

From July 2016 to July 2019, 790 children with indirect PIH were treated by laparoscopic surgery. All patients underwent high ligation surgery with a modified single-site laparoscopic technique mainly performed by extracorporeal suturing with an ordinary closed-eye taper needle (1/2 arc 11 × 34). The clinical data were retrospectively analyzed.

RESULTS

All surgeries were successful without serious complications. A contralateral patent processus vaginalis (CPPV) was found intraoperatively and subsequently repaired in 190 patients (25.4%). The mean operative time was 15 min (8-25 min) for 557 unilateral hernias and 21 min (14-36 min) for 233 bilateral hernias. The mean postoperative stay was 20 h. Minor complications occurred in five patients (0.63%) and were managed properly, with no major impact on the final outcomes. No recurrence was noted in the patients who were followed up for 6-42 months. No obvious scar was present postoperatively.

CONCLUSION

Modified SLPEC of hernia sac high ligation using an ordinary taper needle for repair of indirect PIH is a safe, reliable, and minimally invasive procedure with satisfactory outcome, with no special device being needed. It is easy to learn and perform and is worthy of popularization in the clinical setting.

Construction of a doxycycline inducible lentivirus that expresses stem cell-specific miR-302 cluster

INTRODUCTION

The polycistronic miR-302 cluster encodes five miRNA genes that have an important role in the regulation of embryonic stem cell function. Studies showed that the miR-302 cluster can reprogram both mouse and human fibroblasts to induced pluripotent stem cells (iPSCs) with high efficiency. The aim of this study was to generate an inducible lentivirus that expresses miR-302 cluster in order to further investigate somatic cell reprogramming by these miRNAs.

MATERIALS AND METHODS

The miR-302 cluster was amplified by polymerase chain reaction technique from human genomic DNA and was ligated into pTRIPz, an inducible lentiviral vector.

RESULTS

MRC5 fibroblasts and HEK293 (human embryonic kidney) cells were infected with pTRIPz-302 cluster lentivirus and the family of 302 miRNAs were strongly expressed in HEK293 cells but lowly expressed in MRC5 fibroblasts. When cultured in hESC conditions, MRC5 cells expressed only low levels of DNMT3B, Nanog, Oct4 and Lin28 and failed to show stem cell induction. The red fluorescent expression seen in the majority of MRC5 cells, indicated that the rate of infection by lentivirus was efficient.

DISCUSSION

The efficiency of reprogramming may be improved perhaps by either using a different cell type or a high expression vector with a different type of promoter.

[Clinical safety and efficiency of ultrasonic bone curette used in anterior cervical discectomy and fusion surgery]

Objective: To investigate the safety and efficiency of ultrasonic bone curette used in anterior cervical discectomy and fusion surgery. Methods: As a retrospective study, we collected and analyzed the clinical data of 47 patients receiving anterior cervical discectomy and fusion surgery in Luohe Central Hospital from January 2014 to January 2017, there were 26 males and 21 females with a mean age of (52±9) years. According to the different surgical tools used in the process of decompression by resecting osteophytes or bone like an inverted Chinese character "" located at the posterior margin of the vertebral body, the patients were divided into two groups: ultrasonic bone curette group (group A) and traditional tools group (group B). The operating time, volume of intraoperative blood losing, complications, Japanese Orthopedic Association (JOA) score before and after the operation and improvement rate were recorded in the two groups. The t test was used to compare the data between the two groups. Results: In group A, the operating time was (47±7) min, blood loss was (49±4) ml, 1 case experienced urinary tract infection and there was no cerebrospinal fluid leakage or spinal cord injury. In group B, the operating time was (54±12) min and the blood loss was (117±16) ml, cerebrospinal fluid leakage occurred in 2 patients and the incision healed one-stage by local compression, hoarseness happened in 1 case and it disappeared after 2 weeks, 2 patients had swallowing discomfort and recovered in one month, no spinal cord injury occurred in this group. The operating time and blood loss in group A were lower than those in group B (t=2.691, 20.704, both P<0.05). And the incidence of complications in group A were lower than that in group B (χ(2)=4.157, P=0.041). The JOA score of group A at 3 days after surgery was improved for 39.0% when compared with that before the surgery, and it was improved for 71.6% at one year after the surgery. The JOA score in group B at 3 days after surgery was elevated for 38.7% from that before the surgery, and it increased for 69.4% at one year after the surgery. There was no significant different in JOA score before the surgery, 3 days and one year after the surgery between the two groups (t=0.611, 1.076, 0.061, all P>0.05). Conclusion: In the process of decompression by resecting osteophytes or bone located at the posterior margin of the vertebral body in the anterior cervical discectomy and fusion surgery, ultrasonic bone curette is safe and effective, and it can effectively shorten the operating time, decrease the blood loss and cut down the incidence of complications.

Comparison of hand-sewn versus modified coupled arterial anastomoses in head and neck reconstruction: a single operator's experience

Microvascular coupler devices have gained wide acceptance as an alternative to the traditional hand-sewn technique in reconstructive surgery. However, no study has directly compared the efficacy of the coupler and hand-sewn techniques in arterial anastomosis during head and neck reconstruction surgery. A total of 123 patients who underwent surgery performed by a single surgeon between 2016 and 2018 were included in this retrospective study. The patients were divided into the coupler group and the hand-sewn group according to the technique of arterial anastomosis used. Patients in the coupler group underwent a special procedure including arterial bifurcation to enlarge the recipient artery diameter. Of the 123 free flap surgeries performed, 56 were done using a coupler and 67 with the standard suture technique. One flap in the coupler group failed due to simultaneous arterial and venous thromboses. One flap in the hand-sewn group was lost due to venous compromise. The overall flap survival rate was 98.4% (n=121). There was a significant decrease in anastomotic time when a coupler was used (P<0.001). The complication and flap loss rates were similar in the coupler and hand-sewn groups. The application of the coupler helped to decrease the anastomotic time and achieved satisfactory vessel patency.

Direct investigation of current transport in cells by conductive atomic force microscopy

Currents play critical roles in neurons. Direct observation of current flows in cells at nanometre dimensions and picoampere current resolution is still a daunting task. In this study, we investigated the current flows in hippocampal neurons, PC12 cells and astrocytes in response to voltages applied to the cell membranes using conductive atomic force microscopy (CAFM). The spines in the hippocampal neurons play crucial roles in nerve signal transfer. When the applied voltage was greater than 7.2 V, PC12 cells even show metallic nanowire-like characteristics. Both the cell body and glial filaments of astrocytes yielded CAFM test results that reflect different electrical conductance. To our best knowledge, the electrical characteristics and current transport through components of cells (especially neurons) in response to an applied external voltage have been revealed for the first time at nanometre dimensions and picoampere current levels. We believe that such studies will pave new ways to study and model the electrical characteristics and physiological behaviours in cells and other biological samples.

Oral vaccination with the porcine circovirus type 2 (PCV-2) capsid protein expressed by Lactococcus lactis induces a specific immune response against PCV-2 in mice

AIMS

Porcine circovirus type 2 (PCV2) can cause postweaning, multisystemic wasting syndrome in pigs, which leads to enormous losses in the swine industry worldwide. Here, a genetically engineered Lactococcus strain expressing the main protective antigen of PCV2, the Cap protein, was developed to act against PCV2 infection as an oral vaccine.

METHODS AND RESULTS

Expression of the Cap protein was confirmed via western blot, ELISA and fluorescence microscopy. Over 90% of the recombinant pAMJ399-Cap/MG1363 survived a simulated gastrointestinal transit. It also survived the murine intestinal tract for at least 11 days. Then, the safety and immunogenicity of pAMJ399-Cap/MG1363 in orally immunized mice was evaluated. The levels of the sIgA, IgG and cytokines (IL-4 and IFN-γ) obtained from the mice immunized with pAMJ399-Cap/MG1363 were significantly higher than those in the control groups.

CONCLUSIONS

pAMJ399-Cap/MG1363 can survive in the gastrointestinal transit and effectively induce mucosal, cellular and humoral immune response against PCV2 infection via oral administration.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates the potential of the genetically engineered Lactococcus lactis as a candidate for an oral vaccine against PCV2.

Effects of Lactococcus lactis MG1363 producing fusion proteins of bovine lactoferricin-lactoferrampin on growth, intestinal morphology and immune function in weaned piglet

AIMS

We developed a strategy for localized delivery of the LFCA (lactoferricinlactoferrampin), which is actively synthesized in situ by Lactococcus lactis (pAMJ399-LFCA/LLMG1363), and explored the possibility of using pAMJ399-LFCA/LLMG1363 as an alternative additive diet to antibiotics.

METHODS AND RESULTS

The antimicrobial activities of the LFCA derived from pAMJ399-LFCA/LLMG1363 were tested in vitro. The results showed that LFCA had an inhibitory effect on Staphylococcus aureus, Escherichia coli and Salmonella enteritidis. Then, the pAMJ399-LFCA/LLMG1363 was used as an additive diet for piglets. Our data demonstrated that oral administration of pAMJ399-LFCA/LLMG1363 significantly improved the average daily gain, feed-to-gain ratio, intestinal mucosal integrity and decreased the serum endotoxin and d-lactic acid levels. The mRNA expression levels of intestinal tight junction proteins (including occludin, Claudin-1 and ZO-1) were significantly upregulated by pAMJ399-LFCA/LLMG1363 administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, IL-2, IL-10 and TGF-β levels were significantly increased by pAMJ399-LFCA/LLMG1363. Furthermore, our data revealed that oral administration of pAMJ399-LFCA/LLMG1363 significantly increased the number of general Lactobacillus, and decreased the total viable E. coli counts in the ileum and cecum contents.

CONCLUSIONS

We developed a novel pAMJ399-LFCA/LLMG1363 secreting LFCA, which had probiotic effects on the growth performance, intestinal morphology, intestinal barrier function and immunological indices of weaned piglets.

SIGNIFICANCE AND IMPACT OF THE STUDY

pAMJ399-LFCA/LLMG1363, with probiotic effects on the health of weaned piglets, may be a promising feed additive for weaned piglets.

Fabrication, characterization, and magnetic properties of exchange-coupled porous BaFe8Al4O19/Co0.6Zn0.4Fe2O4 nanocomposite magnets

Fabrication of exchange-coupled nanocomposite magnets has been considered to be the most effective method to achieve the high energy product for advanced permanent magnet applications. In this work, we report a facile auto-combustion synthesis to prepare porous exchange-coupled hard-soft ferrite-based magnetic BaFe8Al4O19-x wt% Co0.6Zn0.4Fe2O4 nanocomposites (where x = 10, 20, 30 and 40), which realize an effective exchange-coupled interaction when the x value is less than 30. Compared with BaFe8Al4O19, the optimized nanocomposite with 20% Co0.6Zn0.4Fe2O4 shows a 70.3% increase in Ms and a 60.4% enhancement in Mr and maintains a high Hc value of 8.8 kOe. The work demonstrates that the auto-combustion synthesis is a promising approach for the fabrication of high-performance ferrite-based permanent magnets.

[Results for the treatment of fresh type thoracolumbar vertebral fracture according to the intraoperative CT scan]

Objective: To evaluate the value of intraoperative CT scanning in the treatment of fresh thoracolumbar burst fractures. Methods: From January 2008 to January 2015 , 161 patients with thoracolumbar fractures in Department of Orthopedics, Luohe City Central Hospital, were divided into two groups: 79 cases were treatment group which were treated with intraoperative CT scan and decompression mode was determined according to CT scan results during the period from October 2012 to January 2015. 82 patients as the observation group were treated without intraoperative CT scan and direct laminectomy were performed during the period. In the treatment group, it is no further decompression of the spinal canal when the CT showed a reduction of the fracture block into the spinal canal, if the intraoperative CT showed that the fractures still occupied the spinal dura mater according to the three-dimensional CT information, the position and the size of the fracture of the spinal canal were determined, and the unilateral laminectomy was performed corresponding to the position of the lamina and intervertebral ligamentum flavum. The operative time, bleeding volume, neurological function, height of the anterior vertebral compression and Cobb angle were compared between the two groups. Results: In the treatment group, CT scan showed 48 cases (60.8%) entered the spinal canal fracture completely or basically reset.31 cases (39.2%) still occupied the spinal canal compression spinal dura mater. There were significant differences in the operation time and bleeding volume between the two groups. The treatment group was less than the control group. There was no infection, secondary spinal cord injury, loose fixation and other complications. There was no difference in the ASIA classification before and after operation(χ(2)=0.268 vs χ(2)=1.372, P>0.05). The anterior vertebral height and COBB angle of the two groups were significantly improved compared with those before operation. There was no significant difference between the two groups in the postoperative height and COBB angle[(40.3±11.8)° vs(82.1±4.2)°, (-10.3±2.6)° vs(6.9±3.3)°, P<0.05], but after 2 years the difference was statistically significant between the two groups, to retain the rear ligament complex treatment group was significantly better than the control group. Conclusions: Patients of thoracolumbar vertebral fracture in hyperextension position combined with internal fixation can achieve good correction effect. Orthopedic postoperative CT scan and according to the results of the scan precision treatment can simplify the operation, there was no difference in clinical efficacy compared with total laminectomy, but some patients avoid the spinal canal decompression and part were treated by small fenestration laminectomy decompression, which is conducive to the protection of spinouts ligament complex integrity.

[Research progress on non-coding RNAs in the molecular pathogenesis of hepatocellular carcinoma]

Primary liver cancer arises from chronic liver disease, and cirrhotic liver gradually develops into dysplastic nodules that eventually form malignant tumors. In recent years, molecular biotechnology development has deepened people's understanding on the pathogenesis of liver cancer. Epigenetic modifications play a significant role in DNA methylation, non-coding RNAs, chromatin remodeling, and histone modification. This review focuses on the progress of currently implicated non-coding RNAs in the molecular pathogenesis of hepatocellular carcinoma, and its potential application in improving the diagnosis and treatment.

[Comparison of percutaneous endoscopic lumbar discectomy versus transforaminal lumbar interbody fusion in treating upper lumbar disc herniation]

Objective: To compare the efficacy of percutaneous endoscopic transforaminal discectomy (PTED) and transforaminal lumbar interbody fusion (TLIF) in the treatment of high lumbar disc herniation. Methods: The clinical data of patients with high lumbar disc herniation from February 2010 to February 2015 were retrospective analyzed. According to the inclusion criteria, a total of 63 cases were enrolled, including PTED group 33 cases, TLIF group 30 cases. The improvement of the two groups before and after surgery was assessed by visual analogue scale (VAS) and Oswestry dysfunction index (ODI). The operative time, intraoperative blood loss, drainage volume at 48 h postoperatively, hospitalization time, number of fluoroscopy, complication, recurrence rate and postoperative recovery were compared between the two groups. The follow-up period was 12 to 33 months. Results: The operation time, intraoperative blood loss, drainage amount and hospitalization time in PTED group were significantly less than those in TLIF group[(71±19) vs (121±22) min, (30±21) vs (317±50) ml, 0 vs (93±29) ml, (3.5±1.9) vs (12.5±2.1) d]. The number of fluoroscopy in PTED group was significantly higher than TLIF group[(16.2±8.3) vs (6.7±4.2)](all P<0.05). There was no significant difference in VAS score and ODI improvement rate between the two groups after operation (both P>0.05). There was no significant difference between the two groups in the excellent rate of surgery and the recurrence rate (both P>0.05). Conclusions: PTED has the advantages of less trauma and bleeding, rapid postoperative recovery in the treatment of upper lumbar disc herniation compared with TLIF, and the curative effect and recurrence rate are similar with TLIF. Therefore, PTED is an effective method for the treatment of upper lumbar disc herniation.

[Clinical observation of postprandial hypotension in patients with hypertensive and coronary heart disease]

Objective: To explore the prevalence and clinical characteristics of postprandial hypotension(PPH) in patients with essential hypertension and coronary heart disease. Methods: A total of 197 patients with essential hypertension and coronary heart disease, who had been treated in the First Department of Cardiology of the Second Hospital of Hebei Medical University from December, 2013 to December, 2014 were included. The patients' blood pressure before breakfast, lunch and dinner and 30, 60, 90, 120 minutes after the meal were monitored. Subjects were classified into PPH group (n=37) and non-PPH group (NPPH, n=160) according to postprandial decrease in systolic blood pressure, to explore the clinical characteristics and related factors and the major adverse cardiac and cerebral vascular events of PPH. Results: Among 197 patients, 37 cases (18.8%) showed at least once postprandial decline in systolic blood pressure greater than and equal to 20 mmHg. The incidence of PPH after breakfast and dinner were higher than lunch (P<0.05). There was no significant difference in the incidence of PPH among different age groups, among patients accompanied with different diseases, and among patients with different dining position (all P>0.05). According to the baseline systolic blood pressure, patients can be divided into 4 groups(<120 mmHg, 120-129 mmHg, 130-139 mmHg, >140 mmHg), the higher the level of the baseline systolic blood pressure was, the higher the incidence of PPH was. And the incidence of major adverse cardiac and cerebral vascular events in patients during hospitalization were increased by PPH. Conclusions: The prevalence of PPH in the patients with essential hypertension and coronary heart disease is 18.8%. The incidence of PPH after breakfast and dinner is higher than lunch. The baseline systolic blood pressure is considered to be the risk factor of PPH. And PPH could lead to an increase of the incidence of major adverse cardiac and cerebral vascular events.

Stabilization of warfarin-binding pocket of VKORC1 and VKORL1 by a peripheral region determines their different sensitivity to warfarin inhibition

Essentials VKORL1 and VKORC1 have a similar overall structure and warfarin-binding pocket. A peripheral region stabilizing this pocket controls warfarin sensitivity of the VKOR paralogs. A human single nucleotide polymorphism in this region renders VKORL1 sensitive to warfarin. A group of warfarin-resistant mutations in VKORC1 acts by disrupting peripheral interactions.

SUMMARY

Background The human genome encodes two paralogs of vitamin-K-epoxide reductase, VKORC1 and VKORL1, that support blood coagulation and other vitamin-K-dependent processes. Warfarin inhibits both enzymes, but VKORL1 is relatively resistant to warfarin. Objectives To understand the difference between VKORL1 and VKORC1, and the cause of warfarin-resistant (WR) mutations in VKORC1. Methods We performed systematic mutagenesis and analyzed warfarin responses with a cell-based activity assay. Mass spectrometry analyses were used to detect cellular redox state. Results VKORC1 and VKORL1 adopt a similar intracellular redox state with four-transmembrane-helix topology. Most WR mutations identified in VKORC1 also confer resistance in VKORL1, indicating that warfarin inhibits these paralogs at a common binding site. A group of WR mutations, distant from the warfarin-binding site, show significantly less resistance in VKORL1 than in VKORC1, implying that their different warfarin responses are determined by peripheral interactions. Remarkably, we identify a critical peripheral region in which single mutations, Glu37Lys or His46Tyr, drastically increase the warfarin sensitivity of VKORL1. In the background of these warfarin-sensitive VKORL1 mutants, WR mutations showing relative less resistance in wild-type VKORL1 become much more resistant, suggesting a structural conversion to resemble VKORC1. At this peripheral region, we also identified a human single nucleotide polymorphism that confers warfarin sensitivity of VKORL1. Conclusions Peripheral regions of VKORC1 and VKORL1 primarily maintain the stability of their common warfarin-binding pocket, and differences of such interactions determine their relative sensitivity to warfarin inhibition. This new model also explains most WR mutations located at the peripheral regions of VKORC1.