Untimely oxidative stress in β-cells leads to diabetes - Role of circadian clock in β-cell function

Diabetes results from a loss of β-cell function. With the number of people with diabetes reaching epidemic proportions globally, understanding mechanisms that are contributing to this increasing prevalence is critical. One such factor has been circadian disruption, with shift-work, light pollution, jet-lag, increased screen time, all acting as potential contributory factors. Though circadian disruption has been epidemiologically associated with diabetes and other metabolic disorders for many decades, it is only recently that there has been a better understanding of the underlying molecular mechanisms. Experimental circadian disruption, via manipulation of environmental or genetic factors using gene-deletion mouse models, has demonstrated the importance of circadian rhythms in whole body metabolism. Genetic disruption of core clock genes, specifically in the β-cells in mice, have, now demonstrated the importance of the intrinsic β-cell clock in regulating function. Recent work has also shown the interaction of the circadian clock and enhancers in β-cells, indicating a highly integrated regulation of transcription and cellular function by the circadian clock. Disruption of either the whole body or only the β-cell clock leads to significant impairment of mitochondrial function, uncoupling, impaired vesicular transport, oxidative stress in β-cells and finally impaired glucose-stimulated insulin secretion and diabetes. In this review, we explore the role of the circadian clock in mitigating oxidative stress and preserving β-cell function.

Counterion binding alters surfactant self-assembly in deep eutectic solvents

Counterion adsorption unexpectedly changes self-assembly behaviour in deep eutectic solvents.

Correction: Expanding analytical tools for characterizing ultrasmall silica-based nanoparticles

Correction for ‘Expanding analytical tools for characterizing ultrasmall silica-based nanoparticles’ by B. Yoo et al., RSC Adv., 2017, 7, 16861–16865.

Translesional pressure gradient and leptomeningeal collateral status in symptomatic middle cerebral artery stenosis

BACKGROUND AND PURPOSE

Leptomeningeal collateral (LMC) status governs the prognosis of large artery occlusive stroke, although factors determining LMC status are not fully elucidated. The aim was to investigate metrics affecting LMC status in such patients by using computational fluid dynamics (CFD) models based on computed tomography angiography (CTA).

METHODS

In this cross-sectional study, patients with recent ischaemic stroke or transient ischaemic attack attributed to atherosclerotic M1 middle cerebral artery (MCA) stenosis (50%-99%) were recruited. Demographic, clinical and imaging data of these patients were collected. Ipsilesional LMC status was graded as good or poor by assessing the laterality of anterior and posterior cerebral arteries in CTA. A CFD model based on CTA was constructed to reflect focal hemodynamics in the distal internal carotid artery, M1 MCA and A1 anterior cerebral artery. Pressure gradients were calculated across culprit MCA stenotic lesions in CFD models. Predictors for good LMC status were sought in univariate and multivariate analyses.

RESULTS

Amongst the 85 patients enrolled (mean age 61.5 ± 10.9 years), 38 (44.7%) had good ipsilesional LMC status. The mean pressure gradient across MCA lesions was 14.8 ± 18.1 mmHg. Advanced age (P = 0.030) and a larger translesional pressure gradient (P = 0.029) independently predicted good LMCs. A lower fasting blood glucose level also showed a trend for good LMCs (P = 0.058).

CONCLUSIONS

Our study suggested a correlation between translesional pressure gradient and maturation of LMCs in intracranial atherosclerotic disease. Further studies with more exquisite and dynamic monitoring of cerebral hemodynamics and LMC evolution are needed to verify the current findings.

A Comparison of Emergency Department Admission Diagnoses and Discharge Diagnoses: Retrospective Study

Objective

To study the accuracy of emergency department admission diagnosis and the effect of investigations on diagnostic accuracy.

Design

Retrospective study in a two-month period.

Setting

Accident & Emergency Department of a public general hospital, which had four in-patient specialties – Medicine, Surgery, Paediatrics and Orthopaedics.

Subjects

All cases admitted through the emergency department in the study period.

Main outcome measures

Degree of correlation between emergency department admission diagnosis and hospital discharge diagnosis.

Results

Of all admission diagnoses, 71.4% fully or partially matched the final discharge diagnoses. The accuracy of diagnosis was statistically better in traumatic cases, the male sex and young adults. Diagnostic accuracy varied with the specialty involved and investigations taken.

Conclusion

History and physical examination remained the most important diagnostic tools in the emergency department. In general, simple investigations available at the emergency department were not helpful in improving diagnostic accuracy.

[Whole Genome Sequencing of Human mtDNA Based on Ion Torrent PGM™ Platform]

OBJECTIVES

To analyze and detect the whole genome sequence of human mitochondrial DNA （mtDNA） by Ion Torrent PGM™ platform and to study the differences of mtDNA sequence in different tissues.

METHODS

Samples were collected from 6 unrelated individuals by forensic postmortem examination, including chest blood, hair, costicartilage, nail, skeletal muscle and oral epithelium. Amplification of whole genome sequence of mtDNA was performed by 4 pairs of primer. Libraries were constructed with Ion Shear™ Plus Reagents kit and Ion Plus Fragment Library kit. Whole genome sequencing of mtDNA was performed using Ion Torrent PGM™ platform. Sanger sequencing was used to determine the heteroplasmy positions and the mutation positions on HVⅠ region.

RESULTS

The whole genome sequence of mtDNA from all samples were amplified successfully. Six unrelated individuals belonged to 6 different haplotypes. Different tissues in one individual had heteroplasmy difference. The heteroplasmy positions and the mutation positions on HVⅠ region were verified by Sanger sequencing. After a consistency check by the Kappa method, it was found that the results of mtDNA sequence had a high consistency in different tissues.

CONCLUSIONS

The testing method used in present study for sequencing the whole genome sequence of human mtDNA can detect the heteroplasmy difference in different tissues, which have good consistency. The results provide guidance for the further applications of mtDNA in forensic science.

[Characteristics of ureteral stone position and dilatation of ureter in patients before treated with endourologic lithotripsy]

OBJECTIVE

To investigate the position and the size of ureteral stone in patients before treated with ureteroscopic lithotripsy or percutaneous nephrolithotomy (PCNL), as well as the dilatation of ureter caused by stone, which may be helpful for better understanding of pathogenesis of ureteral stone and improvement of the diagnosis and treatment in clinic.

METHODS

A total of 129 cases with ureteral stone for endourologic lithotripsy in Peking University People's Hospital from Aug. 2016 to Mar. 2017 were included for the retrospective review. The CT data of the ureteral stones and the ureteral dilatation were collected, including the position of stone, the transverse and longitudinal diameter of stone, and the transverse diameter of dilated upper ureter and ureteropelvic junction (UPJ). The distribution of ureteral stones and dilatation in different parts of ureter were compared and analyzed.

RESULTS

All of the 129 cases of ureteral stone, stones were located at UPJ in 9 cases (7.0%), proximal ureter in 75 (58.0%), ureter crossing external iliac vessel (UEIV) in 6 (4.7%), distal ureter in 26 (20.2%), and ureterovesical junction (UVJ) in 13 (10.1%). The mean transverse diameter of proximal ureteral stones was greater than that of distal ureteral stones [(8.47±2.36) mm vs. (6.74±1.99) mm, P<0.001], as the same as the mean longitudinal diameter [(11.00±4.41) mm vs. (7.50±4.28) mm, P<0.001]. In 114 cases of dilated ureter for stone, the UPJ had a greater transverse diameter compared with the upper ureter [(14.39±6.09) mm vs. (11.45±3.85) mm, P<0.001].

CONCLUSION

The most common location of stone is the proximal ureter in patients for endourologic lithotripsy, as the location in UEIV is rare. Both transverse and longitudinal diameters of stone in proximal ureter are greater than those in distal ureter. For dilated ureter, it is more severe in UPJ than in upper ureter. Traditionally, it is accepted that the stones lodge at 3 sites of natural narrowing in ureter, which may be questioned.

Expanding Analytical Tools for Characterizing Ultrasmall Silica-based Nanoparticles

C' dots are fluorescent inorganic-organic hybrid nanoparticles synthesized in water comprised of a silica core with a covalently embedded near infrared dye, and a polyethylene glycol (PEG) outer layer. C' dots containing the integrin specific ligand, cycloRGDyC, are the first of their kind particles approved for human clinical trials. In the continued clinical development of these nanoparticles, high-resolution analytical approaches are needed. Here we investigate the use of reversed phase high performance liquid chromatography (RP-HPLC) to analyze cycloRGDyC-Cy5-C' dots. Given the stability and protein-like size, we reasoned that these nanoparticles would be compatible under RP-HPLC conditions typically used to characterize peptides and proteins. Our results show that RP-HPLC provides excellent resolution, showing significant heterogeneity of these nanoparticles. C' dots also exhibit unusual peak profiles where RP-HPLC chromatogram peak shapes change from run to run, possibly due to the conformational heterogeneity or charge distribution of the particle surface due to the PEG groups. In addition we describe a novel thiol-mediated release of C' dot ligands to directly estimate cycloRGDyC by exposing the particles to organic thiols. Ligand release is presumably afforded by a reverse Michael reaction mechanism.

Monitoring Mitophagy in Mammalian Cells

In eukaryotes, physiological cell functions rely on the preservation of the size and activity of the mitochondrial network. Mitophagy provides a key contribution in this setting by ensuring the removal of permeabilized or supernumerary mitochondria. Throughout the past decade, mitophagy has attracted considerable attention from both fundamental researchers and translational investigators, both of whom have called for the development of techniques that allow the precise quantification of mitophagy (as opposed to general autophagy). In this chapter, we present morphological, biochemical, and fluorescence-based approaches to measure autophagy in mammalian cells, and discuss recent progress in mouse models for the assessment of mitophagy in vivo.

Fabrication of thermal-resistant gratings for high-temperature measurements using geometric phase analysis

Grating fabrication techniques are crucial to the success of grating-based deformation measurement methods because the quality of the grating will directly affect the measurement results. Deformation measurements at high temperatures entail heating and, perhaps, oxidize the grating. The contrast of the grating lines may change during the heating process. Thus, the thermal-resistant capability of the grating becomes a point of great concern before taking measurements. This study proposes a method that combines a laser-engraving technique with the processes of particle spraying and sintering for fabricating thermal-resistant gratings. The grating fabrication technique is introduced and discussed in detail. A numerical simulation with a geometric phase analysis (GPA) is performed for a homogeneous deformation case. Then, the selection scheme of the grating pitch is suggested. The validity of the proposed technique is verified by fabricating a thermal-resistant grating on a ZrO₂ specimen and measuring its thermal strain at high temperatures (up to 1300 °C). Images of the grating before and after deformation are used to obtain the thermal-strain field by GPA and to compare the results with well-established reference data. The experimental results indicate that this proposed technique is feasible and will offer good prospects for further applications.

The phenomenon of missing doses in a cohort of HIV patients with good adherence to highly active antiretroviral therapy

A self-administered questionnaire survey was conducted in a specialist HIV clinical service in Hong Kong. A total of 76 male Chinese patients who had been on highly active antiretroviral therapy for over one year were enrolled. All except one had undetectable viral load at the time of the assessment. Though a majority (76%) scored 100% in self-reporting adherence rating, one-third of these had in fact missed at least one dose in the preceding four-week period. Men having sex with men had a lower tendency of missing dose than heterosexuals (13.6% versus 42%, P = 0.019). There was no association between missing doses and clinical staging or the regimens. The study revealed that missing doses may occur despite report of almost complete adherence, which, in the long run, could be a cause for concern.

Matrine alleviates early brain injury after experimental subarachnoid hemorrhage in rats: possible involvement of PI3K/Akt-mediated NF-κB inhibition and Keap1/Nrf2-dependent HO-1 inductionn

Matrine is a quinolizidine alkaloid derived from the herb Radix Sophorae Flavescentis, and possesses anti-oxidant, anti-inflammatory and anti-tumoral properties. However, its effectiveness against subarachnoid hemorrhage (SAH) is not well known. In this study, we investigated the effects of matrine on early brain injury (EBI) and the related potential mechanisms following SAH in rats. Our results showed that matrine pretreatment partially alleviated SAH-induced EBI, including neurological deficit, severity of SAH grade, brain edema, and blood-brain barrier (BBB) disruption in rats. In addition, SAH procedure induced BBB disruption with concomitant upregulation of MMP-9 expression and downregulation of tight junction proteins expression of BBB, namely, ZO-1 and occludin, which was partially reversed by matrine pretreatment. Matrine also reduced the increased levels of inflammatory cytokines TNF-α and IL-1β after the SAH operation. SAH induced neural cell apoptosis, as demonstrated by high apoptotic index and increased expression of Bax and caspase-3 proteins, as well as the reduced Bcl-2 expression, which were reversed by matrine pretreatment. Furthermore, matrine pretreatment partially suppressed SAH-induced Akt phosphorylation and IκB-α phosphorylation and degradation, and reduced NF-kB P65 protein levels. The expression of Keap1, Nrf2, and HO-1 proteins was distinctly enhanced in the SAH+matrine group, compared with the SAH+vehicle groups. Matrine pretreatment suppressed SAH-induced MMP-9 expression, which could be partially blocked by HO-1 inhibitor Sn-protoporphyrin IX (SnPP IX) but promoted by phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. Our results suggest that matrine may alleviate EBI after experimental subarachnoid hemorrhage in rats possibly via PI3K/Akt-mediated NF-κB inhibition and Keap1/Nrf2-dependent HO-1 induction.

[Retroperitoneoscopic renal pedicle lymphatic disconnection for chyluria via extra-adipose capsule]

OBJECTIVE

To evaluate the clinical effect of retroperitoneoscopic renal pedicle lymphatic disconnection via extra-adipose capsule in the management of chyluria and to discuss the management of its complications.

METHODS

From August 2013 to June 2008, five patients with chyluria were admitted. All the patients were female, aged from 26 to 73 years, and disease course from 1 to 10 years. All the five patients had complained of intermittently voiding milky urine with varying degrees of weight loss, and fatigue, of whom two presented with flank pain and one with anemia. Their urine chyle tests were confirmed to be positive. Preoperative cystoscopy found that chyluria was from the left side in 3 cases,and from the right side in 2 cases. Their proteinuria ranged from + to ++++. All the cases had been treated with the modified procedure by which lymphatic ligation was performed to hilar vessels and proximalureter via extra-adipose capsule without disconnection of perirenal fat tissues. The operation time, intraoperative blood loss, postoperative intestinal function recovery, catheter time, drainage tube removal time and complications during operation were collected.

RESULTS

All the five cases were performed successfully. The operation time ranged from 75 to 170 minutes, mean (126.0±39.6) minutes, with the intraoperative blood loss 20 to 60 mL, mean (38.0±16.4) mL, and the postoperative intestinal function recovery time 1 to 3 days, mean (1.9±0.4) days. The catheter time was 1 to 4 days, mean (2.1±0.3) days and the drainage tube removal time ranged from 3 to 15 days, mean (9.3±1.8) days. Postoperatively lymphorrhagia was found in two cases. No renal vessels injury occurred during operation. Chyluria of all the patients disappeared on the operation day with negative chyluria test after surgery. Furthermore, urine test revealed that proteinuria was totally negative. No recurrence was detected in our patients in the 9 to 31 months' follow-up.

CONCLUSION

This modified procedure does not have to disconnect perirenal fat tissues and nephropexy during operation. It was characterized with shorter operation time, definitive effect and fewer complications.