Combining low tube voltage and iterative reconstruction for contrast-enhanced CT imaging of the chest-initial clinical experience

AIM

To evaluate the image quality of contrast-enhanced chest computed tomography (CT) with low tube voltage settings using an iterative reconstruction algorithm (iDose4) and standard dose filtered back projection (FBP) CT in patients with normal body mass index (BMI).

MATERIALS AND METHODS

Eighty patients with normal BMI were referred for a contrast-enhanced chest CT. Patients were randomly assigned into two groups: 120 kVp and 80 kVp. Standard convolution FBP was used to reconstruct the 120 kVp group (A) and 80 kVp group (C) image sets and iterative reconstruction (iDose4) was used to reconstruct the 80 kVp group (B) image sets. The mean image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective dose (ED) were calculated for each protocol. Image quality was graded (scale: 1-3) and compared among the three groups.

RESULTS

The radiation dose was 71.35% less for the low-voltage protocol. Noise was significantly lower in the low-voltage images reconstructed with iDose4 (group B) compared with images reconstructed with FBP (group C). Group B had the highest SNR and CNR. There was no difference in subjective image quality scores between groups B and A (p > 0.05).

CONCLUSIONS

Compared with standard FBP reconstruction, the iDose4 iterative reconstruction yields higher SNR, CNR, and better image quality in contrast-enhanced chest CT with low tube voltage settings.

Decreased expression of microRNA-31 associates with aggressive tumor progression and poor prognosis in patients with bladder cancer

PURPOSE

MicroRNA-31 (miR-31) has different expression patterns in various human cancers. Especially in urothelial carcinoma of the bladder, it has been demonstrated to be decreased expression in the invasive tumors and homozygously deleted. However, its clinical significance in human bladder cancer has not yet been elucidated. Thus, the purpose of this study was to investigate the diagnostic and prognostic values of miR-31 in this disease.

METHODS

Expression levels of miR-31 in 126 pairs of bladder cancer and adjacent normal tissues were detected by real-time quantitative RT-PCR assay. To determine its prognostic value, overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.

RESULTS

MiR-31 expression in bladder cancer tissues was significantly lower than those in adjacent normal tissues (mean expression level: 2.1 ± 0.9 vs. 3.8 ± 1.2, P < 0.001). When categorized into low vs. high expression, low miR-31 expression was negatively associated with the tumor stage (P = 0.02), the status of recurrence (P = 0.01), progression (P = 0.01), and death (P = 0.006) of patients with bladder cancer. Moreover, low miR-31 expression clearly predicted poorer PFS (P = 0.001) and OS (P < 0.001). In the multivariate analysis, low miR-31 expression was an independent prognostic factor for both PFS (P = 0.01) and OS (P = 0.008).

CONCLUSION

These findings show that miR-31 may contribute to the progression of bladder cancer and its downregulation may be independently associated with unfavorable PFS and OS, suggesting that miR-31 might be a promising marker for further risk stratification in the treatment of this cancer.

Higher serum retinol binding protein 4 may be a predictor of weak metabolic control in chinese patients with type 2 diabetes mellitus

OBJECTIVE

To investigate relationships between serum levels of retinol binding protein 4 (RBP4) and clinical and metabolic variables in Chinese patients with type 2 diabetes mellitus.

METHODS

A total of 513 patients (286 males/227 females) provided clinical and lifestyle data and blood and urine samples for analysis. Patients were stratified into four quartile groups according to serum RBP4 concentrations.

RESULTS

RBP4 concentration was independently associated with gender, systolic blood pressure, serum triglyceride and creatinine levels, and estimated glomerular filtration rate (eGFR). Hypertension, dyslipidaemia, micro albuminuria and impaired eGFR (<60 ml/min per 1.73 m2) were significantly more prevalent in patients with the highest RBP4 levels than in those with the lowest levels. Increased serum RBP4 was associated with increased risk of hypertension, dyslipidaemia, micro albuminuria and impaired eGFR after adjusting for gender, age, body mass index and duration of diabetes.

CONCLUSION

Serum RBP4 may be a useful marker of overall metabolic control in Chinese patients with type 2 diabetes mellitus.

Comparison of a paraspinal approach with a percutaneous approach in the treatment of thoracolumbar burst fractures with posterior ligamentous complex injury: a prospective randomized controlled trial

OBJECTIVE

This prospective randomized controlled study compared the efficacy and safety of two paraspinal muscle-sparing surgical approaches for the management of neurologically intact patients with thoracolumbar burst fractures and posterior ligamentous complex injuries.

METHODS

Patients were randomized to undergo either percutaneous (n=31) or paraspinal (n=30) fluoroscopically-guided pedicle screw-rod fixation, and were followed for ≥3 years. Preoperative postural reduction was attempted in all patients.

RESULTS

The percutaneous approach was associated with significantly less intraoperative blood loss and shorter duration of surgery and hospitalization, as well as less pain and better functional recovery at 3 months after surgery compared with the paraspinal approach. Paraspinal surgery resulted in significantly better correction of kyphosis and restoration of vertebral height compared with percutaneous surgery. There were no differences in long-term clinical outcomes between the two groups.

CONCLUSIONS

The minimally invasive percutaneous approach appears to be better in cases of successful postural reduction. The paraspinal approach results in better surgical correction and is, therefore, recommended for patients without successful postural reduction.

Exome sequencing-driven discovery of coding polymorphisms associated with common metabolic phenotypes

AIMS/HYPOTHESIS

Human complex metabolic traits are in part regulated by genetic determinants. Here we applied exome sequencing to identify novel associations of coding polymorphisms at minor allele frequencies (MAFs) >1% with common metabolic phenotypes.

METHODS

The study comprised three stages. We performed medium-depth (8×) whole exome sequencing in 1,000 cases with type 2 diabetes, BMI >27.5 kg/m(2) and hypertension and in 1,000 controls (stage 1). We selected 16,192 polymorphisms nominally associated (p < 0.05) with case-control status, from four selected annotation categories or from loci reported to associate with metabolic traits. These variants were genotyped in 15,989 Danes to search for association with 12 metabolic phenotypes (stage 2). In stage 3, polymorphisms showing potential associations were genotyped in a further 63,896 Europeans.

RESULTS

Exome sequencing identified 70,182 polymorphisms with MAF >1%. In stage 2 we identified 51 potential associations with one or more of eight metabolic phenotypes covered by 45 unique polymorphisms. In meta-analyses of stage 2 and stage 3 results, we demonstrated robust associations for coding polymorphisms in CD300LG (fasting HDL-cholesterol: MAF 3.5%, p = 8.5 × 10(-14)), COBLL1 (type 2 diabetes: MAF 12.5%, OR 0.88, p = 1.2 × 10(-11)) and MACF1 (type 2 diabetes: MAF 23.4%, OR 1.10, p = 8.2 × 10(-10)).

CONCLUSIONS/INTERPRETATION

We applied exome sequencing as a basis for finding genetic determinants of metabolic traits and show the existence of low-frequency and common coding polymorphisms with impact on common metabolic traits. Based on our study, coding polymorphisms with MAF above 1% do not seem to have particularly high effect sizes on the measured metabolic traits.

Selenoprotein P and Yunnan endemic sudden cardiac death--an ecological study

The aim of the present study was to explore the role of selenoprotein P (SePP) in the etiology of the endemic sudden cardiac death in Yunnan, China. The levels of SePP of 124 subjects and glutathione peroxidase (GPx) of 119 subjects were measured. The subjects were from the old and new endemic areas and non-endemic areas. The levels of SePP and GPx of the subjects of the old endemic area were significantly higher than those of the subjects of the new endemic area and the non-endemic areas, respectively. The Pearson's correlation among SePP, GPx, and the number of the incident cases of the disease were statistically significant. These correlations show that there is an inverse relationship among the number of patients and the levels of SePP (r  =  - 0.9800, P  =  0.0200) and GPx (r  =  - 0.961, P  =  0.009). The results show that selenium deficiency might play an important role in the incidence of the disease.

Effects of fluoride and chloride on the growth of Chlorella pyrenoidosa

To compare the toxic action of fluoride (F(-)) and chloride (Cl(-)) on freshwater algae, effects of F(-) and Cl(-) on Chlorella pyrenoidosa growth were investigated by determination of the algal biomass and model analysis. Results showed that the exponential growth equation (D = D0 + ae(bT)) may be used to fit the relationship between cell density (D) of C. pyrenoidosa and exposure time (T), but F(-) and Cl(-) have significantly different effects on parameters a (initial quantity of algae at the exponential growth stage) and b (growth constant). In the range of experimental concentrations, F(-) inhibited C. pyrenoidosa growth, and percent inhibition increased with increasing exposure time and F(-) concentration. By contrast, Cl(-) either inhibited or enhanced C. pyrenoidosa growth depending on Cl(-) concentration and exposure time, and percent inhibition increased with increasing Cl(-) concentration but decreased with increasing exposure time. The dose-response equation: I = min + (max - min)/(1 + 10(lgEC50-lgC)) may be used to fit the relationship between percent inhibition (I) and F(-) or Cl(-) concentration (C); however, F(-) was distinct from Cl(-) in terms of effects on parameter 'min'. The EC50 values of F(-) and Cl(-) ranged from 118 to 170 mg/L and 19.73 to 36.33 g/L, respectively; the latter is much higher than the former. Thus F(-) has higher toxicity than Cl(-).

Effects of telomerase activity and apoptosis on ex vivo expansion of cord blood CD34(+) cells

OBJECTIVE

Ex vivo expansion of CD34(+) cells has become critically important in order to obtain sufficient haematopoietic stem cells for clinical application. Among major regulators involved in ex vivo expansion, telomerase activity and apoptosis have been revealed to be closely linked to cell cycle progression. However, all exact roles remain to be elucidated. Here, change in telomerase activity and level of apoptosis in cord blood (CB) CD34(+) cells were evaluated together with specific cell population growth rate during ex vivo culture.

MATERIALS AND METHODS

CD34(+) cells isolated from human CB were expanded ex vivo over a 28-day period. Besides monitoring cell proliferation kinetics of the CD34(+) cells, changes in telomerase activity and apoptotic levels were investigated. Several relevant genes were quantified by qRT-PCR during the culture period.

RESULTS

Significant elevation of telomerase activity had close relationship to activation of CB CD34(+) cell expansion. Peak apoptotic level was accompanied by a remarkable decline in cell-specific growth rate, and apoptotic level of differentiated CD34(-) population was significantly higher than that of the CD34(+) population.

CONCLUSION

Although telomerase activity was activated during the culture, expansion of CB CD34(+) cells seemed to be more susceptible to apoptotic suppression when cultured ex vivo, which implied that apoptosis may serve as a rate-limiting factor involved in controlling expansion efficiency.

Ghrelin promotion of oocyte maturation via ERK1/2 pathway in ovis aries

Ghrelin has recently garnered increasing attention in biomolecular studies. Ghrelin's growth hormone secretagogue receptor type 1a (GHS--R) is a pleiotropic modulator of diverse biological functions, including energy homeostasis and reproduction. This study sought to understand the ways in which ghrelin impacts ERK1/2 and p90rsk during the ovis aries oocyte maturation process. We applied different concentrations of ghrelin and of ghrelin receptor inhibitor (D--Lys3--GHRP--6) to ovis aries oocytes and observed the effects on the ERK1/2 and p90rsk pathway. The ERK1/2 and p90rsk pathway plays an essential role in the in vitro maturation of ovis aries oocytes. This study discovered that ERK1/2 and p90 rsk pathway, during the ovis aries oocyte maturation, was associated with maturation of ovis aries oocyte in vitro.

Docetaxel-cisplatin might be superior to docetaxel-capecitabine in the first-line treatment of metastatic triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) may be more sensitive to platinum. This study was to compare platinum-based regimen with nonplatinum regimen in the first-line treatment of advanced TNBC.

PATIENTS AND METHODS

Eligible metastatic TNBC (mTNBC) women without prior treatment for advanced disease were randomized (1 : 1) to receive either docetaxel-cisplatin (TP) or docetaxel -capecitabine (TX) q3w for up to 6 cycles, until disease progression or unacceptable toxicity. The primary end point was objective response rate (ORR) and the secondary end points included progression-free survival (PFS) and overall survival (OS). In total 53 patients were enrolled.

RESULTS

The median follow-up was 24 months. ORR was higher in the TP group than in the TX group (63.0% versus 15.4%, P = 0.001). PFS was more than doubled (10.9 months versus 4.8 months, P < 0.001) and median OS was also greatly improved (32.8 months versus 21.5 months, P = 0.027). Toxic effects were not different except G3/4 vomiting and G2/3 hand-foot syndrome.

CONCLUSIONS

This study suggested that cisplatin-based chemotherapy was superior to capecitabine-based regimen in the first-line treatment of mTNBC, as measured by ORR, PFS and OS. Further large-scale study should be warranted. These results are not sufficient to change clinical practice.

Expression of NR2B in different brain regions and effect of NR2B antagonism on learning deficits after experimental subarachnoid hemorrhage

Approximately 50% of patients who survived after aneurysmal subarachnoid hemorrhage (SAH) have cognitive or neurobehavioral dysfunction. The mechanisms are not known. NR2B, one of the subunits of N-methyl-d-aspartate (NMDA) receptors, has been proved to be an important factor for synapse function and behavior cognition. Experiment 1 aimed to investigate the timecourse of the NR2B expression in the cortex, hippocampus, and cerebellum after SAH in rats. In experiment 2, we assessed the effect of Ro 25-6981 (a specific NR2B antagonist) on regulation of learning deficits and behavioral activity following SAH. All SAH animals were subjected to injection of autologous blood into the prechiasmatic cistern once on day 0. NR2B was assessed by Western blot analysis and immunohistochemistry. Cognitive and memory changes were investigated in the Morris water maze. As a result, the expression of NR2B was decreased remarkably in SAH groups compared with the control group and the low ebb was on days 1-3. The immunohistochemical staining demonstrated expression of NR2B was present mainly in the neurons in all of the three different regions, such as the cortex, hippocampus, and cerebellum. After Ro 25-6981 intraperitoneal administration, learning deficits induced by SAH was markedly aggravated and clinical behavior scale was also significantly decreased. Our results suggest that NR2B expression is down-regulated in the brain after experimental SAH and NR2B antagonism resulted in augmentation of the development of cognitive dysfunction after SAH.

IL-17 and IFN-γ production in peripheral blood following BCG vaccination and Mycobacterium tuberculosis infection in human

BACKGROUND

During Mycobacterium tuberculosis (Mtb) infection, cells of the immune system rely on cytokines to regulate the activity of other immune and structural cells such as IFN-gamma and IL-4. Recent studies suggest that Th17 cells secreting IL-17 may play a potential role in tuberculosis (TB) development.

AIM

To assess the effect of IL-17 on TB development, we provide a systematic review on the production of IL-17, IFN-gamma and IL-4 in infants or children vaccinated with BCG and in TB patients.

MATERIALS AND METHODS

The literature relevant with IL-17 and IFN-gamma production with or without IL-4 on human TB was retrieved from PubMed, EMBASE, Cochrane Library, BIOSIS Previews and the China Biomedicine Literature Databases (CBM) using the search terms "Interleukin-17 or Th17 cells" and "Tuberculosis". The information of included studies, the production of IL-17 and IFN-gamma responding to antigens in the peripheral blood in vitro, was independently extracted by the first two researchers and subsequently qualitatively analyzed.

RESULTS

Nine studies from a total of 226 retrieved publications met the criteria. These included studies showed that BCG vaccination induced dramatically high level of IL-17 similar to IFN-gamma; The level of IL-17 and IFN-gamma were low while IL-4 was high in patients with active TB; IL-17 and IFN-gamma had a similar trend of increase during the conversion from active to latent TB while IL-4 inclined to decrease in this process.

CONCLUSIONS

IL-17 acts as an effector molecule similar to IFN-gamma after BCG vaccination and Mtb infection to protect human against TB. The current findings do not support IL-17 as an inducer of tissue damage in TB.

Submucous rather than myenteric neurons are activated by mucosal biopsy supernatants from irritable bowel syndrome patients

BACKGROUND

We previously showed that colonic mucosal biopsy supernatants from patients with irritable bowel syndrome (IBS) activate neurons of the human submucous plexus, an area with densely packed immune cells. Based on the concept that mucosa-nerve signaling is altered in IBS, we tested in this study whether the nerve sensitizing effect of IBS mucosal biopsy supernatants is more prominent in the submucous than myenteric plexus.

METHODS

Fast neuroimaging with the voltage-sensitive dye Di-8-ANEPPS was used to record activity of guinea-pig submucous and myenteric neurons after application of constipation (C)- and diarrhea (D)-IBS supernatants (three each) and four supernatants from healthy control subjects. Results are based on recordings from 4731 neurons.

KEY RESULTS

Control supernatants did not evoke significant responses in submucous or myenteric neurons. In contrast, all IBS supernatants evoked a significant spike discharge (median 3.6 Hz) in 46% of submucous neurons. This activation was significantly stronger than in the myenteric plexus where even twice the amount of supernatants evoked a lower spike frequency (median 2.1Hz) in only 8.5% of neurons. Pharmacological studies revealed serotonin, histamine, and proteases as components mediating neuronal activation. Individual application of these components revealed that only serotonin evoked a significantly stronger activation of submucous compared with myenteric neurons.

CONCLUSIONS & INFERENCES

Direct neuronal activation by IBS mucosal biopsy supernatants is primarily a feature of submucous rather than myenteric neurons. This is associated with a stronger excitation of submucous neurons by serotonin. The plexus-specific effects support the concept that altered mucosa-nerve signaling underlies disturbances in IBS.

Mechanisms that underlie the induction of vasodilation in pulmonary artery by rutin

AIM

Rutin, also known as violaguercitrin, is a bioflavonoid and has a wide range of biological activity. However, the effect of this compound on arteries is not elucidated. Therefore, the objective of this study was to investigate the mechanism underling the induction of vasodilation in pulmonary artery (PA) by the natural product, rutin.

METHODS

Firstly, the isometric tension of the artery rings was studied in vitro with force-electricity transducers. In PA endothelium-intact (EI) rings, rutin elicited concentration-dependent relaxation after the PA rings were pre-contracted by phenylephrine (PE), but induced mesenteric artery (MA) vasoconstriction. Inhibited the endothelial nitric oxide synthase (eNOS) by NG-Nitro-L-arginine Methyl Ester (L-NAME) or removed the PA endothelium would decrease the relaxation effect of rutin.

RESULTS

The NO production was increased in rutin-treated bovine pulmonary artery endothelial cells (BPAECs) detected by fluorescent probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM), which verify the functional study results. Moreover, western blot analysis revealed that rutin increased the phosphorylation of eNOS at Ser 1177, but decreased the phosphorylation of eNOS at Thr 495, and did not affect the overall expression of eNOS.

CONCLUSION

These results suggested that rutin-induced relaxation of PAs share NO-eNOS activation pathways, including phosphorylation of Ser 1177, and dephosphorylation at Thr 495. Rutin also has specific action because it exerts a vasodilator influence on the PAs but not MAs.

A comparison of the clinical characteristics of women with recurrent major depression with and without suicidal symptomatology

BACKGROUND

The relationship between recurrent major depression (MD) in women and suicidality is complex. We investigated the extent to which patients who suffered with various forms of suicidal symptomatology can be distinguished from those subjects without such symptoms.

METHOD

We examined the clinical features of the worst episode in 1970 Han Chinese women with recurrent DSM-IV MD between the ages of 30 and 60 years from across China. Student's t tests, and logistic and multiple logistic regression models were used to determine the association between suicidality and other clinical features of MD.

RESULTS

Suicidal symptomatology is significantly associated with a more severe form of MD, as indexed by both the number of episodes and number of MD symptoms. Patients reporting suicidal thoughts, plans or attempts experienced a significantly greater number of stressful life events. The depressive symptom most strongly associated with lifetime suicide attempt was feelings of worthlessness (odds ratio 4.25, 95% confidence interval 2.9-6.3). Excessive guilt, diminished concentration and impaired decision-making were also significantly associated with a suicide attempt.

CONCLUSIONS

This study contributes to the existing literature on risk factors for suicidal symptomatology in depressed women. Identifying specific depressive symptoms and co-morbid psychiatric disorders may help improve the clinical assessment of suicide risk in depressed patients. These findings could be helpful in identifying those who need more intense treatment strategies in order to prevent suicide.

Signal transduction pathways and transcriptional mechanisms of ABCB1/Pgp-mediated multiple drug resistance in human cancer cells

Multiple drug resistance (MDR), defined as the ability of tumour cells to survive exposure to many chemotherapeutic agents, is a major cause of treatment failure in human cancers. The membrane transporter P-glycoprotein (Pgp, encoded by the ABCB1 [adenosine triphosphate-binding cassette, subfamily B, member 1] gene) is the main mechanism for decreased intracellular drug accumulation in human MDR cancer. ABCB1/Pgp-mediated MDR involves several signal transduction pathways and transcription factors. Activation of these signal transduction pathways influences the prognosis of MDR human cancer. Signalling pathways involved in ABCB1/Pgp-mediated MDR include the mitogen-activated protein kinase (MAPK), c-Jun NH(2)-terminal kinase (JNK), p38, cyclic adenosine monophosphate-dependent protein kinase, phosphatidylino sitol 3-kinase and protein kinase C signalling pathways. This review summarizes the biological characteristics, target points and signalling cascade mediators of these pathways. Drugs targeted against these pathways may provide new therapies for treatment of ABCB1/Pgp-mediated MDR.

The beneficial effect of Radix Dipsaci total saponins on bone metabolism in vitro and in vivo and the possible mechanisms of action

The purpose of this study is to investigate the anti-osteoporotic effects of Radix Dipsaci total saponins (RTS). We showed that RTS was able to improve bone properties by either an increase of osteoblastic activity or a decrease in osteoclastic activity.

INTRODUCTION

Radix Dipsaci has long been used as an anti-osteoporotic drug. The present study investigates the anti-osteoporotic effects of RTS.

METHODS

Three-month-old female rats were randomly assigned into a sham-operated group (sham) and five ovariectomy (OVX) subgroups, namely, OVX with vehicle (OVX), OVX with 17β-ethinylestradiol (E(2)), and OVX with graded doses of RTS (50, 100, or 200 mg/kg/d). RTS and E(2) were administered orally, daily from 1 week after OVX treatment for 4 months. Bone mass, turnover, and strength were evaluated by dual-energy X-ray absorptiometry, biochemical markers, and the three-point bending test. The trabecular bone microarchitecture was assessed by microCT. In vitro experiments were performed to determine the potential molecular mechanisms of the anti-osteoporotic effect of RTS.

RESULTS

RTS prevented the loss of bone mass induced by OVX. The preventive effect on bone loss was primarily indicated by decreasing levels of bone turnover markers and confirmed by the changes in urinary calcium and phosphorus excretion. The treatment also enhanced the biomechanical strength of bone and prevented the deterioration of trabecular bone microarchitecture. RTS induced MC3T3-E1 and primary osteoblastic cell maturation and differentiation and increased bone formation by increasing BMP-2 synthesis. In addition, RTS inhibited osteoclastogenesis through an increase in osteoprotegrin and a decrease in NF-kB ligand expression in vitro.

CONCLUSIONS

RTS treatment can effectively suppress the loss of bone mass induced by OVX and in vitro evidence suggests this could be through actions on both osteoblasts and osteoclasts.

Antitumor effects of interferon-alpha on cell growth and metastasis in human nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a highly malignant and frequently metastasized tumor, and the prognosis is very poor when distant metastases occur. Recently, immunotherapy is becoming a promising therapeutic approach. Interferon-α (IFN-α) represents the cytokines exhibiting the longest record of use in clinical oncology. In this study, we examined the antitumor effects of IFN-α1b on NPC. The results showed that recombinant human IFN-α1b (hIFN-α1b) suppressed cell growth, induced a G1-phase cell cycle arrest in vitro, increased the expression of p16 and pRb, and decreased the expression of CCND1 and CDK6. In vivo analyses showed that either recombinant adeno-associated virus (rAAV)-IFN-α1b or hIFN-α1b treatment inhibited tumor growth and metastasis, reduced intratumoral microvessel density, increased cell apoptosis and necrosis, and induced prolonged survival. Notably, rAAV-IFN-α1b or hIFN-α1b treatment led to significantly higher serum levels of IL-12 and GM-CSF in mice compared to respective controls. Our findings suggest that IFN-α1b acts as a multifunctional antitumor agent in NPC, which may have important therapeutic implications.