Quantitative Cytochrome P450 3A4 Induction Risk Assessment Using Human Hepatocytes Complemented with Pregnane X Receptor-Activating Profiles.

Reliable in vitro to in vivo translation of cytochrome P450 (CYP) 3A4 induction potential is essential to support risk mitigation for compounds during pharmaceutical discovery and development. In this study, a linear correlation of CYP3A4 mRNA induction potential in human hepatocytes with the respective pregnane-X receptor (PXR) activation in a reporter gene assay using DPX2 cells was successfully demonstrated for 13 clinically used drugs. Based on this correlation, using rifampicin as a positive control, the magnitude of CYP3A4 mRNA induction for 71 internal compounds at several concentrations up to 10 µM (n = 90) was predicted within 2-fold error for 64% of cases with only a few false positives (19%). Furthermore, the in vivo area under the curve reduction of probe CYP substrates was reasonably predicted for eight marketed drugs (carbamazepine, dexamethasone, enzalutamide, nevirapine, phenobarbital, phenytoin, rifampicin, and rufinamide) using the static net effect model using both the PXR activation and CYP3A4 mRNA induction data. The liver exit concentrations were used for the model in place of the inlet concentrations to avoid false positive predictions and the concentration achieving twofold induction (F2) was used to compensate for the lack of full induction kinetics due to cytotoxicity and solubility limitations in vitro. These findings can complement the currently available induction risk mitigation strategy and potentially influence the drug interaction modeling work conducted at clinical stages. SIGNIFICANCE STATEMENT: The established correlation of CYP3A4 mRNA in human hepatocytes to PXR activation provides a clear cut-off to identify a compound showing an in vitro induction risk, complementing current regulatory guidance. Also, the demonstrated in vitro-in vivo translation of induction data strongly supports a clinical development program although limitations remain for drug candidates showing complex disposition pathways, such as involvement of auto-inhibition/induction, active transport and high protein binding.

Association between dietary anthocyanidins intake and depression among US adults: a cross-sectional study (NHANES, 2007-2010 and 2017-2018).

BACKGROUND: Anthocyanidins encompass a diverse array of compounds that possess notable anti-inflammatory and antioxidant properties with pharmacological activity. However, the correlation between the consumption of anthocyanidins through diet and its impact on depression has yet to be investigated. METHODS: This study utilized the Food and Nutrient Database for Dietary Studies (FNDDS) expanded flavonoid intake database, as well as data from the National Health and Nutrition Examination Survey (NHANES) from the years 2007 to 2010 and 2017 to 2018. The analysis of the collected data was conducted in R, following the guidelines outlined in the official NHANES user guide "Stratified Multi-stage Probability Sampling". Three different models were developed using logistic regression to assess the protective effects of T3 (representing the highest intake of anthocyanidins) against depression. Additionally, the study aimed to investigate whether there existed a non-linear relationship between the dietary intake of anthocyanidins and the prevalence of depression by employing restricted cubic spline (RCS) analysis. RESULTS: A total of 6,845 eligible participants were included in this cross-sectional study, with their data appropriately weighted to represent a population of 89.8 million people in the United States of America. The results demonstrated that individuals diagnosed with depression had a significantly lower dietary intake of anthocyanidins compared to those without depression (P < 0.0001). Moreover, significant differences were observed among different participant groups regarding socioeconomic status and the presence of chronic physical illnesses (such as hypertension, glucose status, and chronic kidney disease risk, etc.) (P < 0.05). After adjustment for covariates, participants with the highest intake of anthocyanins (T3) demonstrated a significantly reduced risk of depression [ORT3 = 0.67, 95%CI: (0.48-0.95), (Ptrend= 0.02]. Furthermore, the RCS analysis revealed a significant linear relationship between dietary anthocyanidin intake and depression (P for non-linear = 0.5876). CONCLUSION: Our findings reveal a negative association between dietary anthocyanidin intake and depression.

The developmental regulator PatD modulates assembly of the cell-division protein FtsZ in the cyanobacterium Anabaena sp. PCC 7120.

FtsZ is a tubulin-like GTPase that polymerizes to initiate the process of cell division in bacteria. Heterocysts are terminally differentiated cells of filamentous cyanobacteria that have lost the capacity for cell division and in which the ftsZ gene is downregulated. However, mechanisms of FtsZ regulation during heterocyst differentiation have been scarcely investigated. The patD gene is NtcA dependent and involved in the optimization of heterocyst frequency in Anabaena sp. PCC 7120. Here, we report that the inactivation of patD caused the formation of multiple FtsZ-rings in vegetative cells, cell enlargement, and the retention of peptidoglycan synthesis activity in heterocysts, whereas its ectopic expression resulted in aberrant FtsZ polymerization and cell division. PatD interacted with FtsZ, increased FtsZ precipitation in sedimentation assays, and promoted the formation of thick straight FtsZ bundles that differ from the toroidal aggregates formed by FtsZ alone. These results suggest that in the differentiating heterocysts, PatD interferes with the assembly of FtsZ. We propose that in Anabaena FtsZ is a bifunctional protein involved in both vegetative cell division and regulation of heterocyst differentiation. In the differentiating cells PatD-FtsZ interactions appear to set an FtsZ activity that is insufficient for cell division but optimal to foster differentiation.

Predictors of postoperative biochemical remission in acromegaly.

PURPOSE: Acromegaly is a rare neuroendocrine condition that can lead to significant morbidity. Despite China's vast population size, studies on acromegaly remain sparse. This study aimed to investigate the clinical characteristics and predictors of biochemical remission after surgery for acromegaly using the China Acromegaly Patient Association (CAPA) database. METHODS: A retrospective nationwide study was conducted using patient-reported data from CAPA database between 1998 and 2018. The principal component analysis (PCA) and logistic regression analysis were employed to determine independent predictors of biochemical remission at 3 months in patients after surgery. RESULTS: Of the 546 surgical cases (mean age: 36.8 years; 59.5% females), macroadenomas and invasive tumors (Knosp score 3-4) were 83.9% and 64.1%, respectively. Ninety-five percent of patients were treated with endonasal surgery and 36.8% exhibited biochemical remission at 3-months postoperatively. The following independent predictors of biochemical remission were identified: preoperative growth hormone (GH) levels between 12 and 28 µg/L [odds ratio (OR) = 0.58; 95% confidence interval (CI), 0.37-0.92; p = 0.021], preoperative GH levels > 28 µg/L (OR = 0.55; 95% CI, 0.34-0.88; p = 0.013), macroadenoma (OR = 0.56; 95% CI, 0.32-0.96; p = 0.034), giant adenomas (OR = 0.14; 95% CI, 0.05-0.38; p < 0.001), Knosp score 3-4 (OR = 0.37; 95% CI, 0.24-0.57; p < 0.001), and preoperative medication usage (OR = 2.32; 95% CI, 1.46-3.70; p < 0.001). CONCLUSIONS: In this nationwide study spanning over two decades, we highlight that higher preoperative GH levels, large tumor size, and greater extent of tumor invasiveness are associated with a lower likelihood of biochemical remission at 3-months after surgery, while preoperative medical therapy increases the chance of remission.

Clinical Characteristics of and Medical Interventions for COVID-19 in Hemodialysis Patients in Wuhan, China.

BACKGROUND: Reports indicate that those most vulnerable to developing severe coronavirus disease 2019 (COVID-19) are older adults and those with underlying illnesses, such as diabetes mellitus, hypertension, or cardiovascular disease, which are common comorbidities among patients undergoing maintenance hemodialysis. However, there is limited information about the clinical characteristics of hemodialysis patients with COVID-19 or about interventions to control COVID-19 in hemodialysis centers. METHODS: We collected data retrospectively through an online registration system that includes all patients receiving maintenance hemodialysis at 65 centers in Wuhan, China. We reviewed epidemiologic and clinical data of patients with laboratory-confirmed COVID-19 between January 1, 2020 and March 10, 2020. RESULTS: Of 7154 patients undergoing hemodialysis, 154 had laboratory-confirmed COVID-19. The mean age of the 131 patients in our analysis was 63.2 years; 57.3% were men. Many had underlying comorbidities, with cardiovascular disease (including hypertension) being the most common (68.7%). Only 51.9% of patients manifested fever; 21.4% of infected patients were asymptomatic. The most common finding on chest computed tomography (CT) was ground-grass or patchy opacity (82.1%). After initiating comprehensive interventions-including entrance screening of body temperature and symptoms, universal chest CT and blood tests, and other measures-new patients presenting with COVID-19 peaked at 10 per day on January 30, decreasing to 4 per day on February 11. No new cases occurred between February 26 and March 10, 2020. CONCLUSIONS: We found that patients receiving maintenance hemodialysis were susceptible to COVID-19 and that hemodialysis centers were high-risk settings during the epidemic. Increasing prevention efforts, instituting universal screening, and isolating patients with COVID-19 and directing them to designated hemodialysis centers were effective in preventing the spread of COVID-19 in hemodialysis centers.

Application of a gut-immune co-culture system for the study of N-glycan-dependent host-pathogen interactions of Campylobacter jejuni.

An in vitro gut-immune co-culture model with apical and basal accessibility, designed to more closely resemble a human intestinal microenvironment, was employed to study the role of the N-linked protein glycosylation pathway in Campylobacter jejuni pathogenicity. The gut-immune co-culture (GIC) was developed to model important aspects of the human small intestine by the inclusion of mucin-producing goblet cells, human enterocytes and dendritic cells, bringing together a mucus-containing epithelial monolayer with elements of the innate immune system. The utility of the system was demonstrated by characterizing host-pathogen interactions facilitated by N-linked glycosylation, such as host epithelial barrier functions, bacterial invasion and immunogenicity. Changes in human intestinal barrier functions in the presence of 11168 C. jejuni (wildtype) strains were quantified using GICs. The glycosylation-impaired strain 11168 ΔpglE was 100-fold less capable of adhering to and invading this intestinal model in cell infectivity assays. Quantification of inflammatory signaling revealed that 11168ΔpglE differentially modulated inflammatory responses in different intestinal microenvironments, suppressive in some but activating in others. Virulence-associated outer membrane vesicles produced by wildtype and 11168ΔpglE C. jejuni were shown to have differential composition and function, with both leading to immune system activation when provided to the gut-immune co-culture model. This analysis of aspects of C. jejuni infectivity in the presence and absence of its N-linked glycome is enabled by application of the gut-immune model, and we anticipate that this system will be applicable to further studies of C. jejuni and other enteropathogens of interest.

Parallel Speciation of Wild Rice Associated with Habitat Shifts.

The occurrence of parallel speciation strongly implies the action of natural selection. However, it is unclear how general a phenomena parallel speciation is since it was only shown in a small number of animal species. In particular, the adaptive process and mechanisms underlying the process of parallel speciation remain elusive. Here, we used an integrative approach incorporating population genomics, common garden, and crossing experiments to investigate parallel speciation of the wild rice species Oryza nivara from O. rufipogon. We demonstrated that O. nivara originated multiple times from different O. rufipogon populations and revealed that different O. nivara populations have evolved similar phenotypes under divergent selection, a reflection of recurrent local adaptation of ancient O. rufipogon populations to dry habitats. Almost completed premating isolation was detected between O. nivara and O. rufipogon in the absence of any postmating barriers between and within these species. These results suggest that flowering time is a "magic" trait that contributes to both local adaptation and reproductive isolation in the origin of wild rice species. Our study thus demonstrates a convincing case of parallel ecological speciation as a consequence of adaptation to new environments.

Long noncoding RNA CDKN2B-AS1 interacts with transcription factor BCL11A to regulate progression of cerebral infarction through mediating MAP4K1 transcription.

The effective therapeutic approach of cerebral infarction is limited because of its underlying complexity. Recently, multiple long noncoding RNAs (lncRNAs) have been identified in the pathogenesis of cerebral infarction. Here, the current study aims to explore the interaction among lncRNA cyclin-dependent kinase inhibitor-2B-antisense RNA 1 (CDKN2B-AS1), transcription factor B-cell lymphoma/leukemia 11A (BCL11A), and MAPKK kinase kinase 1 (MAP4K1) and further investigate whether they affect cerebral infarction progression. The expression of CDKN2B-AS1, BCL11A, and MAP4K1 was altered in lymphocytes extracted from patients with cerebral infarction. In order to identify their roles in regulatory T (Treg) cells, the proliferation and apoptosis of the CD4+CD25+ Treg cells were examined, and levels of IL-4, IL-10, and TGF-ß were determined. Also, the RNA crosstalk among CDKN2B-AS1, BCL11A, and MAP4K1 was validated. Finally, we established a rat model of middle cerebral arterial occlusion to evaluate the neurologic impairment and cerebral infarction volume. The results revealed that lymphocytes in patients with cerebral infarction presented with the up-regulated expression of CDKN2B-AS1. Moreover, BCL11A could specifically bind to CDKN2B-AS1 and MAP4K1 promoter so as to inhibit MAP4K1. Moreover, it was observed that down-regulated CDKN2B-AS1 inhibited CD4+CD25+ Treg-cell proliferation, reduced levels of IL-4, IL-10, and TGF-ß and cerebral infarction volume, and elevated MAP4K1 expression. Collectively, our study provides evidence that CDKN2B-AS1 silencing could increase MAP4K1 expression to inhibit the CD4+CD25+ Treg-cell proliferation by reducing enrichment of transcription factor BCL11A, thereby protecting against cerebral infarction progression, highlighting a promising therapeutic strategy for treating cerebral infarction.-Lei, J.-J., Li, H.-Q., Mo, Z.-H., Liu, K.-J., Zhu, L.-J., Li, C.-Y., Chen, W.-L., Zhang, L. Long noncoding RNA CDKN2B-AS1 interacts with transcription factor BCL11A to regulate progression of cerebral infarction through mediating MAP4K1 transcription.

Use of Postpartum Magnetic Resonance Imaging for Diagnosis and Classification of Retained Placenta Tissue.

OBJECTIVE: To study the potential application of magnetic resonance imaging (MRI) for classification of retained placental tissue (RPT) in the uterus postnatally. METHODS: Twenty-two patients with clinically or pathologically proven RPT were studied. RESULTS: The thickness ratio (D1/D2) of invaded (D1) to normal (D2) myometrium could be categorized into 3 groups (>0.6, 0.1-0.6, and <0.1) correlating with the 3 types of RPT: accreta vera (RPA), increta (RPI), and percreta (RPP) (r = -0.861, P < 0.01). After uterine arterial embolization, the RPT showed lower signal intensity than the myometrium without flow voids on T2-weighted images. Two cases of RPP showed gradual enhancement, except 1 case of infection and 2 cases that did not involve enhancement examinations, whereas 17 cases of RPA and RPI showed early enhancement. CONCLUSIONS: Magnetic resonance imaging can facilitate diagnosis of RPT severity. Dynamic contrast enhancement can indicate RPT activity and blood supply, thereby ensuring appropriate clinical decision making.

Ideal T1 laminar screw fixation based on computed tomography morphometry.

BACKGROUND: The application of laminar screws is an alternative fixation for the first thoracic vertebra (T1). This paper is to determine the anatomical characteristics for adequate laminar screw fixation, and present a modified method of sagittal reconstruction of T1 to provide more accurate measurements. METHODS: Computed tomography (CT) images of 62 patients (32 males, 30 females) were used for the analysis. The following parameters of the T-1 lamina were measured using Mimics software: lamina length, axis angle, minimal outer cortical width, cancellous width, minimal outer cortical height, cancellous height, and spinous process height. Right or left modified sagittal reconstructions (parallel to right or left screws) were innovatively used for measurement. RESULTS: There were no significant differences between the left and right sides for each measurement performed (P > 0.05), but significant differences were detected between males and females (P < 0.05). The mean length of the T1 lamina was 32.8 mm of the T1 minimal outer cortical width was 7.4 mm, and 3.8% of males had a minimal outer cortical width < 5 mm, while 8.6% of females had a minimal outer cortical width < 5 mm. The mean minimal outer cortical height was 10.8 mm, and 1.9% of males had a minimal outer cortical height < 9 mm, while 7.7% of females had a minimal outer cortical height < 9 mm. CONCLUSION: This study suggests there are no anatomical limitations for T1 laminar screw placement in most people. The modified sagittal reconstruction method described allows for easy and precise measurement to aid in the insertion of laminar screws in T1, and gives good visualization of laminar screw insertion direction.

[Effect of Muxiang Shunqi Pill on Digestive Disorders of Prephase Uremia Patients and Its Mechanism].

Objective To observe the effect of Muxiang Shunqi Pill (MSP) on digestive disorders of prephase uremia patients, and to study its underlying mechanism. Methods A total of 40 prephase uremia patients with gastrointestinal symptoms were randomly and equally assigned to the MSP group and the Mosapride group. Besides, 20 subjects with normal physical examinations were recruited as the control. Patients in the MSP group took MSP, 6 g each time, three times per day, taken 30 min after dinner. Those in the Mosaprido group took Mosapride Tablet (MT) , 5 mg each time, three times per day, taken 30 min before diner. The therapeutic course for all was 4 weeks. The clinical curative effect was observed. Electrogastrogram, serum levels of gastrin (GAS) and motilin (MTL) , safety and recurrence rate were evaluated. Results The total effective rate was 90% (18/20) and the recurrence rate was 15% (320) in the MSP group, higher than those of the Mosapride group [60%(12/20) , X² =4. 80, P =0. 025; 45% (9/20) , X² =4. 29, P =0. 025]. Compared with before treatment in the same group, the percentage of normal rhythm increased, the bradygastria rate was lowered, serum levels of GAS and MTL increased in the two groups after treatment (P <0. 05, P <0. 01). Compared with the Mosapride group, the bradygastria rate decreased more obviously, serum levels of GAS and MTL were increased more in the MSP group (P <0. 05, P <0. 01). Conclusion MSP could effectively improve digestive disorders of prephase uremia patients, which might be achieved through promoting gastrointestinal motility and regulating ser- um levels of gastrointestinal hormones.

RNase E forms a complex with polynucleotide phosphorylase in cyanobacteria via a cyanobacterial-specific nonapeptide in the noncatalytic region.

RNase E, a central component involved in bacterial RNA metabolism, usually has a highly conserved N-terminal catalytic domain but an extremely divergent C-terminal domain. While the C-terminal domain of RNase E in Escherichia coli recruits other components to form an RNA degradation complex, it is unknown if a similar function can be found for RNase E in other organisms due to the divergent feature of this domain. Here, we provide evidence showing that RNase E forms a complex with another essential ribonuclease-the polynucleotide phosphorylase (PNPase)-in cyanobacteria, a group of ecologically important and phylogenetically ancient organisms. Sequence alignment for all cyanobacterial RNase E proteins revealed several conserved and variable subregions in their noncatalytic domains. One such subregion, an extremely conserved nonapeptide (RRRRRRSSA) located near the very end of RNase E, serves as the PNPase recognition site in both the filamentous cyanobacterium Anabaena PCC7120 and the unicellular cyanobacterium Synechocystis PCC6803. These results indicate that RNase E and PNPase form a ribonuclease complex via a common mechanism in cyanobacteria. The PNPase-recognition motif in cyanobacterial RNase E is distinct from those previously identified in Proteobacteria, implying a mechanism of coevolution for PNPase and RNase E in different organisms.

Superiority of laparoscopy in the peritoneal dialysis catheter reset surgery.

Peritoneal dialysis catheter surgery has been used in clinical treatment for nearly 40 years, and open surgery under local anesthesia is the conventional method. However, catheter displacement after open surgery is still the thorny issue during our clinical practice. Then the reset surgery is often required to be taken again. Nowadays, laparoscopic peritoneal dialysis catheter draws our attention due to its advantages of accurate positioning, smaller incision, and less pain, and its clinical application has been limited. While laparoscopic surgery is recognized, there are few relevant studies on whether there is difference during the catheter reset process between the two surgical approaches. In this study, we mainly discussed the rate of secondary catheter migration, the incidence of complications after catheter reset for two surgical approaches and the hospital stay as well as the total clinical cost for the two surgical approaches. In this study, we retrospectively analyzed 25 cases of end-stage renal disease, who received catheterization for peritoneal dialysis and regular peritoneal dialysis in our hospital from March 2010 to December 2013, and had a medical history of catheter migration. We collected the relevant clinical data for all patients. Fifteen patients selected laparoscopic catheter reset, and 10 patients selected the traditional surgical method for catheter reset by themselves. For all patients enrolled, we analyzed the incidence of secondary catheter migration and postoperative complications, hospitalization time, and total cost for different methods of reset. Through the studies above, we found that laparoscopic peritoneal dialysis catheter surgery offered accurate catheter location and a small incision that was easy to heal. Besides, the incidence of postoperative complications for the laparoscopic surgery was lower than that for traditional surgical approach for catheter reset. The average hospitalization time for laparoscopic surgery was shorter than that for the traditional surgical approach. The total cost of laparoscopic surgery was more than that of the traditional surgery. Therefore, the rational application of a laparoscopic peritoneal dialysis catheter and reset surgery can increase the success rate of peritoneal dialysis, reduce the complications, shorten hospitalization time of patients, and thus enhance patient's confidence to stick it out.

Value of micro-CT for monitoring spinal microvascular changes after chronic spinal cord compression.

Neurological degeneration can occur after compression of the spinal cord. It is widely accepted that spinal cord compression leads to ischemic lesions and ultimately neurological dysfunction due to a narrowed spinal canal. Therefore, an in-depth understanding of the pathogenesis of spinal cord compression injury is required to help develop effective clinical interventions. In the present study, we propose a new method of quantitative 3D micro-CT to observe microvascular events in a chronic spinal cord compression rat model. A total of 36 rats were divided into two groups: sham control group (n = 12) and compressive spinal cord injury group (n = 24). Rats were scarified at four weeks after surgery. In each group, CD34 micro-vessel immunohistochemical staining was performed in half of the animals, while micro-CT scanning was performed in the other half. Microvessel density (MVD) was measured after immunohistochemical staining, while the vascular index (VI) was measured in 3D micro-CT. In comparison with sham control, abnormal somatosensory evoked potentials (SEP) can be seen in all 24 cases of the compression group, and VI shows the amount of microvessels reduced consistently and significantly (p < 0.01). A significant correlation is also found between MVD and VI (r = 0.95, p < 0.01). These data suggest that quantitative 3D micro-CT is a sensitive and promising tool for investigating microvascular changes during chronic compressive spinal cord injury.

The regulation of HanA during heterocyst development in cyanobacterium Anabaena sp. PCC 7120.

In response to deprivation of combined nitrogen, the filamentous cyanobacterium Anabaena sp. strain PCC 7120 develops heterocyst, which is specifically involved in the nitrogen fixation. In this study, we focused on the regulation of HanA, a histone-like protein, in heterocyst development. Electrophoretic mobility shift assay results showed that NtcA, a global nitrogen regulator necessary for heterocyst differentiation, could bind to two NtcA-binding motifs in the hanA promoter region. qPCR results also showed that NtcA may regulate the expression of hanA. By using the hanA promoter-controlled gfp as a reporter gene and performing western blot we found that the amount of HanA in mature heterocysts was decreased gradually.

Immunogenicity and safety of boosting with a recombinant two-component SARS-CoV-2 vaccine: two randomized, parallel-controlled, phase 2 studies.

BACKGROUND: Recombinant protein vaccines are vital for broad protection against SARS-CoV-2 variants. This study assessed ReCOV as a booster in two Phase 2 trials. RESEARCH DESIGN AND METHODS: Study-1 involved subjects were randomized (1:1:1) to receive 20 µg ReCOV, 40 µg ReCOV, or an inactivated vaccine (COVILO®) in the United Arab Emirates. Study-2 participating individuals were randomized (1:1:1) to receive 20 µg ReCOV (pilot batch, ReCOV HA), 20 µg ReCOV (commercial batch, ReCOV TC), or 30 µg BNT162b2 (COMIRNATY®) in the Philippines. The primary immunogenicity objectives was to compare the geometric mean titer (GMT) and seroconversion rate (SCR) of neutralizing antibodies induced by one ReCOV booster dose with those of inactivated vaccine and BNT162b2, respectively, at 14 days post-booster. RESULTS: Heterologous ReCOV booster doses were safe and induced comparable immune responses to inactivated vaccines and BNT162b2 against Omicron variants and the prototype. They showed significant advantages in cross-neutralization against multiple SARS-CoV-2 variants, surpassing inactivated vaccines and BNT162b2, with good immune persistence. CONCLUSIONS: Heterologous ReCOV boosting was safe and effective, showing promise in combating COVID-19. The study highlights ReCOV's potential for enhanced protection, supported by strong cross-neutralization and immune persistence. CLINICAL TRIAL REGISTRATION: Study-1, www.clinicaltrials.gov, identifier is NCT05323435; Study-2, www.clinicaltrials.gov, identifier is NCT05084989.

ppGpp metabolism is involved in heterocyst development in the cyanobacterium Anabaena sp. strain PCC 7120.

When deprived of a combined-nitrogen source in the growth medium, the filamentous cyanobacterium Anabaena sp. PCC 7120 (Anabaena) can form heterocysts capable of nitrogen fixation. The process of heterocyst differentiation takes about 20 to 24 h, during which extensive metabolic and morphological changes take place. Guanosine tetraphosphate (ppGpp) is the signal of the stringent response that ensures cell survival by adjusting major cellular activities in response to nutrient starvation in bacteria, and ppGpp accumulates at the early stage of heterocyst differentiation (J. Akinyanju, R. J. Smith, FEBS Lett. 107:173-176, 1979; J Akinyanju, R. J. Smith, New Phytol. 105:117-122, 1987). Here we show that all1549 (here designated relana) in Anabaena, homologous to relA/spoT, is upregulated in response to nitrogen deprivation and predominantly localized in vegetative cells. The disruption of relana strongly affects the synthesis of ppGpp, and the resulting mutant, all1549Ωsp/sm, fails to form heterocysts and to grow in the absence of a combined-nitrogen source. This phenotype can be complemented by a wild-type copy of relana. Although the upregulation of hetR is affected in the mutant, ectopic overexpression of hetR cannot rescue the phenotype. However, we found that the mutant rapidly loses its viability, within a time window of 3 to 6 h, following the deprivation of combined nitrogen. We propose that ppGpp plays a major role in rebalancing the metabolic activities of the cells in the absence of the nitrogen source supply and that this regulation is necessary for filament survival and consequently for the success of heterocyst differentiation.

Altered diurnal variation and localization of clock proteins in the remnant kidney of 5/6 nephrectomy rats.

AIM: To investigate the localization and diurnal variation of clock proteins (BMAL1, PER2) and clock output protein (DBP) in the remnant kidney of 5/6 nephrectomy rats (STNx). METHODS: Male wistar rats were randomly divided into sham STNx group (Control) and STNx group. Rats were synchronized 12 weeks to the light: dark cycle 12:12 with light on from 07.00 hours (Zeitgeber time ZT 0). Kidneys were collected to detect the localization and expression rhythm of clock proteins (BMAL1, PER2 and DBP) every 4 h throughout the day by immunohistochemistry and Western blotting. RESULTS: Clock proteins showed diurnal rhythm in the kidney of the control. But diurnal rhythm of clock proteins changed in the STNx rats. Acrophase of BMAL1, DBP and PER2 advanced 4 h, respectively; mesor of clock proteins increased in the STNx rats. BMAL1 was located in endothelial cells of glomerulus and tubular interstitial vasculars, and it was also expressed in nucleus of tubular cells in cortex and medulla. PER2 was mainly expressed in proximal tubular cells at the juncture of cortex and medulla. DBP was widely expressed in the kidney. The localization of BMAL1 and PER2 were changed in remnant kidneys of the STNx group. CONCLUSION: The localization and diurnal variation of BMAL1, DBP and PER2 are changed in remnant kidney of 5/6 nephrectomy rats and are involved in diurnal rhythm of renal function.

Effects of chronotherapy of benazepril on the diurnal profile of RAAS and clock genes in the kidney of 5/6 nephrectomy rats.

This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system (RAAS) and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy (STNx) were established. Animals were randomly divided into 4 groups: sham STNx group (control), STNx group, morning benazepril group (MB) and evening benazepril group (EB). Benazepril was intragastrically administered at a dose of 10 mg/kg/day at 07:00 and 19:00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light:dark cycle of 12:12 for 12 weeks. Systolic blood pressure (SBP), 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity (RA), angiotensin II (AngII) and aldosterone (Ald) by radioimmunoassay (RIA) and the mRNA expression profile of clock genes (bmal1, dbp and per2) by real-time PCR at 12 weeks. Our results showed that no significant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Ald and RA content of a day between the MB group and EB group. The expression peak of bmal1 mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.

[HBeAg seroconversion achieved by sequential peginterferon alfa-2a therapy in chronic hepatitis B patients with unsatisfactory end point following entecavir treatment].

OBJECTIVE: To investigate the efficacy and safety of peginterferon alfa-2a (Peg-IFNa-2a) therapy for treating chronic hepatitis B (CHB) in patients who failed to achieve a satisfactory end point with entecavir (ETV) treatment. METHODS: Fifty-seven CHB patients with positivity for hepatitis B e antigen (HBeAg) who had completed a standard ETV monotherapy course, of at least 96 weeks, and who had achieved a virological response (defined as HBV DNA less than 500 copies/ml) but without HBeAg seroconversion (defined as 0.227 PEI U/ml less than HBeAg less than or equal to 50 PEI U/ml) were enrolled in the study. The patients were randomly assigned to receive a 48-week treatment with Peg -IFNa-2a (experimental group, n = 27) or continued ETV therapy (control group, n = 30). Serum samples were collected from all patients for assessment of biochemical, virological and serological responses to treatment. Inter-group differences were statistically evaluated by t-test or Chi-squared test. RESULTS: The baseline levels of alanine aminotransferase, hepatitis B surface antigen (HBsAg), and HBeAg were similar between the patients comprising the experimental and controls groups. At treatment week 48, the experimental group showed significantly higher rates of HBeAg clearance (Peg-IFNa-2a: 40.7% vs. ETV: 16.7%, x2 = 4.079, P less than 0.05) and seroconversion (37.0% vs. 13.3%, x2 = 5.110, P less than 0.05). The experimental group also showed higher rates of HBsAg clearance (7.4% vs. 0%) and HBV DNA relapse (11.1% vs. 0%), but the differences did not reach statistical significance (x2 = 2.307 and 3.519, both P more than 0.05). However, the level of HBsAg was significantly lower in the experimental group (2866.0+2580.4 vs. 4335.8+2650.0 IU/ml, t = 5.11, P less than 0.05). CONCLUSION: HBeAg-positive CHB patients with unsatisfactory response to initial ETV monotherapy achieved HBeAg seroconversion and clearance following sequential Peg-IFN a-2a treatment.