Epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China:a hospital-based retrospective study

Traumatic spinal cord injury is potentially catastrophic and can lead to permanent disability or even death.China has the largest population of patients with traumatic spinal cord injury.Previous studies of traumatic spinal cord injury in China have mostly been regional in scope;national-level studies have been rare.To the best of our knowledge,no national-level study of treatment status and economic burden has been performed.This retrospective study aimed to examine the epidemiological and clinical features,treatment status,and economic burden of traumatic spinal cord injury in China at the national level.We included 13,465 traumatic spinal cord injury patients who were injured between January 2013 and December 2018 and treated in 30 hospitals in 11 provinces/municipalities representing all geographical divisions of China.Patient epidemiological and clinical features,treatment status,and total and daily costs were recorded.Trends in the percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department and cost of care were assessed by annual percentage change using the Joinpoint Regression Program.The percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department did not significantly change overall(annual percentage change,-0.5%and 2.1%,respectively).A total of 10,053(74.7%)patients underwent surgery.Only 2.8%of patients who underwent surgery did so within 24 hours of injury.A total of 2005(14.9%)patients were treated with high-dose(≥500 mg)methylprednisolone sodium succinate/methylprednisolone(MPSS/MP);615(4.6%)received it within 8 hours.The total cost for acute traumatic spinal cord injury decreased over the study period(-4.7%),while daily cost did not significantly change(1.0%increase).Our findings indicate that public health initiatives should aim at improving hospitals’ability to complete early surgery within 24 hours,which is associated with improved sensorimotor recovery,increasing the awareness rate of clinical guidelines related to high-dose MPSS/MP to reduce the use of the treatment with insufficient evidence.

Prevotella and succinate treatments altered gut microbiota,increased laying performance,and suppressed hepatic lipid accumulation in laying hens

Background This work aimed to investigate the potential benefits of administering Prevotella and its primary metabolite succinate on performance,hepatic lipid accumulation and gut microbiota in laying hens.Results One hundred and fifty 58-week-old Hyline Brown laying hens,with laying rate below 80%and plasma triglyceride(TG)exceeding 5 mmol/L,were used in this study.The hens were randomly allocated into 5 groups and subjected to one of the following treatments:fed with a basal diet(negative control,NC),oral gavage of 3 mL/hen saline every other day(positive control,PC),gavage of 3 mL/hen Prevotella melaninogenica(10^(7)CFU/mL,PM)or 3 mL/hen Prevotella copri(10^(7)CFU/mL,P.copri)every other day,and basal diet supplemented with 0.25%sodium succinate(Succinate).The results showed that PM and P.copri treatments significantly improved laying rate compared to the PC(P<0.05).The amount of lipid droplet was notably decreased by PM,P.copri,and Succinate treatments at week 4 and decreased by P.copri at week 8(P<0.05).Correspondingly,the plasma TG level in Succinate group was lower than that of PC(P<0.05).Hepatic TG content,however,was not significantly influenced at week 4 and 8(P>0.05).PM treatment increased(P<0.05)the mRNA levels of genes PGC-1βand APB-5B at week 4,and ACC and CPT-1 at week 8.The results indicated enhanced antioxidant activities at week 8,as evidenced by reduced hepatic malondialdehyde(MDA)level and improved antioxidant enzymes activities in PM and Succinate groups(P<0.05).Supplementing with Prevotella or succinate can alter the cecal microbiota.Specifically,the abundance of Prevotella in the Succinate group was significantly higher than that in the other 4 groups at the family and genus levels(P<0.05).Conclusions Oral intake of Prevotella and dietary supplementation of succinate can ameliorate lipid metabolism of laying hens.The beneficial effect of Prevotella is consistent across different species.The finding highlights that succinate,the primary metabolite of Prevotella,represents a more feasible feed additive for alleviating fatty liver in laying hens.

Therapeutic efficacy of methylprednisolone sodium succinate via diverse administration routes for mid-to high-frequency sudden sensorineural hearing loss

BACKGROUND Sudden sensorineural hearing loss(SSNHL),characterized by a rapid and unexplained loss of hearing,particularly at moderate to high frequencies,presents a significant clinical challenge.The therapeutic use of methylprednisolone sodium succinate(MPSS)via different administration routes,in combination with conventional medications,remains a topic of interest.AIM To compare the therapeutic efficacy of MPSS administered via different routes in combination with conventional drugs for the treatment of mid-to high-frequency SSNHL.METHODS The medical records of 109 patients with mid-to high-frequency SSNHL were analyzed.The patients were divided into three groups based on the route of administration:Group A[intratympanic(IT)injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection],Group B(intravenous injection of MPSS combined with mecobalamin and Ginkgo biloba leaf extract injection),and Group C(single IT injection of MPSS).The intervention effects were compared and analyzed.RESULTS The posttreatment auditory thresholds in Group A(21.23±3.34)were significantly lower than those in Groups B(28.52±3.36)and C(30.23±4.21;P<0.05).Group A also exhibited a significantly greater speech recognition rate(92.23±5.34)than Groups B and C.The disappearance time of tinnitus,time to hearing recovery,and disappearance time of vertigo in Group A were significantly shorter than those in Groups B and C(P<0.05).The total effective rate in Group A(97.56%)was significantly greater than that in Groups B and C(77.14%and 78.79%,χ^(2)=7.898,P=0.019).Moreover,the incidence of adverse reactions in Groups A and C was significantly lower than that in Group B(4.88%,3.03%vs 2.57%,χ^(2)=11.443,P=0.003),and the recurrence rate in Group A was significantly lower than that in Groups B and C(2.44%vs 20.00%vs 21.21%,χ^(2)=7.120,P=0.028).CONCLUSION IT injection of MPSS combined with conventional treatment demonstrates superior efficacy and safety compared to systemic administration via intravenous infusion and a single IT injection of MPSS.This approach effectively improves patients'hearing and reduces the risk of disease recurrence.

Ischemic accumulation of succinate induces Cdc42 succinylation and inhibits neural stem cell proliferation after cerebral ischemia/reperfusion

Ischemic accumulation of succinate causes cerebral damage by excess production of reactive oxygen species. However, it is unknown whether ischemic accumulation of succinate affects neural stem cell proliferation. In this study, we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery. We found that succinate levels increased in serum and brain tissue(cortex and hippocampus) after ischemia/reperfusion injury. Oxygen-glucose deprivation and reoxygenation stimulated primary neural stem cells to produce abundant succinate. Succinate can be converted into diethyl succinate in cells. Exogenous diethyl succinate inhibited the proliferation of mouse-derived C17.2 neural stem cells and increased the infarct volume in the rat model of cerebral ischemia/reperfusion injury. Exogenous diethyl succinate also increased the succinylation of the Rho family GTPase Cdc42 but repressed Cdc42 GTPase activity in C17.2 cells. Increasing Cdc42 succinylation by knockdown of the desuccinylase Sirt5 also inhibited Cdc42 GTPase activity in C17.2 cells. Our findings suggest that ischemic accumulation of succinate decreases Cdc42 GTPase activity by induction of Cdc42 succinylation, which inhibits the proliferation of neural stem cells and aggravates cerebral ischemia/reperfusion injury.

Influence of ganglioside combined with methylprednisolone sodium succinate on efficacy and neurological function in patients with acute myelitis

BACKGROUND Acute myelitis(AM)can lead to sudden sensory,motor and autonomic nervous dysfunction,which negatively affects their daily activities and quality of life,so it is necessary to explore optimization from a therapeutic perspective to curb the progression of the disease.AIM To investigate the effect of ganglioside(GM)combined with methylprednisolone sodium succinate(MPSS)on the curative effect and neurological function of patients with AM.METHODS First,we selected 108 AM patients visited between September 2019 and September 2022 and grouped them based on treatment modality,with 52 patients receiving gamma globulin(GG)+MPSS and 56 patients receiving GM+MPSS,assigned to the control group(Con)and observation group(Obs),respectively.The therapeutic effect,neurological function(sensory and motor function scores),adverse events(AEs),recovery(time to sphincter function recovery,time to limb muscle strength recovery above grade 2,and time to ambulation),inflammatory factors(IFs)[interleukin(IL)-6,C-reactive protein(CRP),and tumor necrosis factor(TNF)-α]and other data of the two groups were collected for evaluation and comparison.RESULTS The Obs had:(1)A significantly higher response rate of treatment than the Con;(2)Higher scores of sensory and motor functions after treatment that were higher than the baseline(before treatment)and higher than the Con levels;(3)Lower incidence rates of skin rash,gastrointestinal discomfort,dyslipidemia,osteoporosis and other AEs;(4)Faster posttreatment recovery of sphincter function,limb muscle strength and ambulation;and(5)Markedly lower posttreatment IL-6,CRP and TNF-αlevels than the baseline and the Con levels.CONCLUSION From the above,it can be seen that GM+MPSS is highly effective in treating AM,with a favorable safety profile comparable to that of GG+MPSS.It can significantly improve patients’neurological function,speed up their recovery and inhibit serum IFs.

Design and manufacture of emulsion liquid membrane based on various amine extractants for separation and extraction of succinic acid from fermentation broth

The aim of this study was to design a new emulsion liquid membrane(ELM)system for the separation of succinic acid from aqueous solutions.The concentration of succinic acid varied from 20 to 60 mmol·L^(-1).The prepared ELM system includes tributylamine(TBA)as a carrier,commercial kerosene as a solvent,Span 80 as a surfactant,and Na2CO3as a stripping agent.In order to control the membrane swelling,different values of cyclohexanone were added to the membrane phase.The effect of various empirical variables on the extraction of the succinic acid such as acid concentration in the feed solution,initial feed concentration,carrier concentration,the stirring speed of the extraction,Na2CO3,surfactant,and cyclohexanone concentrations,and treat ratio in the ELM system.The best result was obtained when TBA was used as the carrier.The final acid extraction efficiency was independent of pH variations of the aqueous feed solution.The extraction of succinic acid solution with a concentration of 40 mmol·L^(-1)was improved by increasing the treat ratio 1:7-1:3,stripping phase concentration 0.5-1.5 mol·L^(-1),stirring speed 300-500 r·min^(-1)and cyclohexanone concentration in the membrane phase 1.2-1.6 mol·L^(-1).No considerable effect on the extraction rate was observed for the carrier concentration in the membrane phase.But,the surfactant concentration in the feed phase showed a dual effect on the extraction efficiency.

Highly improved cyclic stability of Ni-rich/Li batteries with succinic anhydride as electrolyte additive and underlying mechanism

Lithium-metal battery based on Ni-rich cathode provides high energy density but presents poor cyclic stability due to the unstable electrode/electrolyte interfaces on both cathode and anode.In this work,we report a new strategy to address this issue.It is found that the cyclic stability of Ni-rich/Li battery can be significantly improved by using succinic anhydride(SA) as an electrolyte additive.Specifically,the capacity retention of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/Li cell is improved from 14% to 83% after 200cycles at 1 C between 3.0 and 4.35 V by applying 5% SA.The underlying mechanism of SA contribution is understood by comparing the effects of malic anhydride(MA) and citraconic anhydride(CA), both of which share a similar molecular structure to SA but show different effects.On anode side,SA can but MA and CA cannot form a protective solid electrolyte interphase(SEI) on Li anode.On cathode side,three anhydrides can suppress the formation of hydrogen fluoride from electrolyte oxidation decomposition,but SA behaves best.Typically,MA shows adverse effects on the interface stability of Li anode and NCM811 cathode,which originates from its high acidity.Though the acidity of MA can be mitigated by substituting a methyl for one H atom at its C=C bond,the substituent CA cannot compete with SA in cyclic stability improvement of the cell,because the SEI resulting from CA is not as robust as that from SA,which is related to the binding energy of the SEI components.This understanding reveals the importance of the electrolyte acidity on the Ni-rich cathode and the robustness of the SEI on Li anode,which is helpful for rationally designing new electrolyte additives to further improve the cyclic stability of high-energydensity Ni-rich/Li batteries.

Insight into the green route to dimethyl succinate by direct esterification of bio-based disodium succinate using CO_(2)and CH_(3)OH

The fermentation for succinic acid production outperforms other methods by low energy consumption and environmental benignity,with the resulting products mainly as disodium succinate(DSA).By directly esterifying DSA using CO_(2) and CH3OH,it is expected to avoid the use of inorganic acids.By high-resolution mass spectrometry analysis and theoretical calculation,this study establishes that the reaction consists of three steps,i.e.,first forming 3-carboxypropanoate,then monomethyl succinate(MMS),and finally dimethyl succinate(DMS).A detailed kinetic analysis is further performed,the results demonstrate that the transformation of DSA to MMS is regarded to be a second-order reaction for reactant DSA,while the transformation of MMS to DMS is a first-order reaction for reactant MMS.The activation energy for the generation of MMS from DSA is 37.15 kJ·mol^(-1),and that for the generation of DMS from MMS is 85.80 kJ·mol^(-1),indicating the latter one is the rate-determining step.

异叶南星的化学成分研究

目的 :对异叶南星的化学成分进行研究。方法 :采用硅胶柱色谱、薄层色谱对异叶南星的化学成分进行分离 ,并用理化常数和光谱鉴定其结构。结果 :从异叶南星中分离出 4个化合物 ,分别为十八酸单甘酯 (glycerolmonostearicacid ,Ⅰ ) ,β 谷甾醇 (β sitosterol,Ⅱ )、葫萝卜甙 (daucosterol,Ⅲ )、琥珀酸 (succinicacid ,Ⅳ ) ,结论 :化合物Ⅰ。

聚乳酸与聚丁二酸丁二醇酯共混体系发泡行为的研究

通过熔融共混法制备聚乳酸/聚丁二酸丁二醇酯(PLA/PBS)共混体系和PLA/PBS/反应型增容剂(Cp)共混体系,并通过间歇式釜压发泡成型制得泡沫样品,研究了PLA/PBS共混体系和PLA/PBS/Cp共混体系的结晶行为、相态结构、流变行为和发泡行为。结果表明,PBS的加入对PLA降温结晶的影响不大,其熔体弹性有所提升,且PBS含量的变化对共混体系泡孔形态的影响较小;在PLA/PBS/Cp共混体系中,Cp的加入对共混体系中PLA的结晶性能有明显的提高;另外随着Cp含量的增加,其熔体弹性也显著增加;Cp可以有效地提高PLA与PBS间的相容性,改善泡孔的形态。

洋葱假单胞菌产脂肪酶条件的优化

采用Rashid N p-nPP比色法,通过单因素试验和正交试验对洋葱假单胞菌(Pseudomonas cepacia)产脂肪酶的培养基主要成分和发酵条件进行优化,以提高聚丁二酸丁二醇酯(PBS)的生物降解速率。结果表明,该菌种产脂肪酶的最适培养基为菜子油5.0 g/L,酵母膏0.5 g/L,乳化剂Tween-60 2.5 g/L,培养基初始pH 8.0;最适培养条件为接种量9%,培养温度35℃,摇床转速130 r/min,培养时间3 d。在此优化培养基条件下,洋葱假单胞菌产脂肪酶活性可达32.935 U/mL。

不同端基结构聚丁二酸丁二醇酯的合成和生物降解研究

以丁二酸、丁二醇为原料,通过对不同端基的聚丁二酸丁二醇酯(PBS)进行合成和降解,研究了羟基封端、羧基封端和等摩尔比的PBS在堆肥土土壤悬浮液中的降解情况。通过检测降解过程中失重率的变化及降解前后薄膜表面形貌的变化,得出不同端基结构PBS的降解性能。

降解菌株的筛选及其对聚丁二酸丁二醇酯薄膜的降解

从活性污泥中筛选得到1株具有聚丁二酸丁二醇酯(PBS)降解能力的菌株LSU 1601,经菌体形态特征、菌落培养特征、生理生化鉴定和16S rDNA基因序列分析,初步鉴定为德氏食酸菌(Acidovorax de1afiedii)。结果表明,菌株LSU1601在培养温度为30℃、培养基起始pH值为6.8、培养时间为48 h以及振荡转速为120 r/min的条件下,具有较高的产PBS降解酶的能力;同时菌株在培养温度为30℃,培养基起始pH值为6.8的条件下,经84 h的培养,对PBS薄膜的降解率可达到48.2%;经微生物降解作用,PBS薄膜表面出现明显侵蚀痕迹,且随着降解时间的增加,侵蚀作用更加明显;PBS经微生物降解产生了1,4丁二醇单体、1,4-丁二酸单体以及丁二酸-丁二醇二聚体,未发现其他的寡聚体。

Comparsion of the Effects of Succinate and NADH on Postmortem Metmyoglobin Redcutase Activity and Beef Colour Stability

In two experiments, the effects of succinate and NADH（reduced nicotinamide adenine dinucleotide） on metmyoglobin reductase activity and electron transport chain-linked metmyoglobin reduction were investigated and compared. In experiment 1, metmyoglobin（MetMb）, substrate and inhibitors were incubated with mitochondria. Comparsion of the effects of succinate and NADH on MetMb reduction was investigated. The MetMb percentage in sample treated with 8 mol L-1 succinate decreased by about 69% after 3 h incubation, and the effect was inhibited by the addition of 10 mol L-1 electron transfer chain complex II inhibitor malonic acid; the MetMb percentage in samples treated with 2 mol L-1 NADH decreased by 56% and the effect was inhibited by the addition of 0.02 mol L-1 electron transport chain complex I inhibitor rotenone. These results indicated that electron transport chain played an important role in MetMb reduction. Both complex II and complex I take part in the MetMb reduction in mitochondria through different pathways. NADH-MetMb reduction system was less stable than succinateMetMb system. In experiment 2, the beef longissimus dorsi muscle was blended with different concentrations of succinate or NADH. Enhancing patties with higher concentration of succinate or NADH improved colour stability in vacuum packaged samples（P〈0.05）. These results verified that mitochondria electron transport chain is related to the MetMb reduction in meat system.

Succinate dehydrogenase-deficient gastrointestinal stromal tumors

Most gastrointestinal stromal tumors(GISTs)are characterized by KIT or platelet-derived growth factor alpha(PDGFRA)activating mutations.However,there are still 10%-15%of GISTs lacking KIT and PDGFRA mutations,called wild-type GISTs(WT GISTs).Among these so-called WT GISTs,a small subset is associated with succinate dehydrogenase(SDH)deficiency,known as SDH-deficient GISTs.In addition,GISTs that occur in Carney triad and Carney-Stratakis syndromerepresent specific examples of SDH-deficient GISTs.SDH-deficient GISTs locate exclusively in the stomach,showing predilection for children and young adults with female preponderance.The tumor generally pursues an indolent course and exhibits primary resistance to imatinib therapy in most cases.Loss of succinate dehydrogenase subunit B expression and overexpression of insulin-like growth factor 1 receptor(IGF1R)are common features of SDH-deficient GISTs.In WT GISTs without succinate dehydrogenase activity,upregulation of hypoxia-inducible factor 1αmay lead to increased growth signaling through IGF1R and vascular endothelial growth factor receptor(VEGFR).As a result,IGF1R and VEGFR are promising to be the novel therapeutic targets of GISTs.This review will update the current knowledge on characteristics of SDH-deficient GISTs and further discuss the possible mechanisms of tumorigenesis and clinical management of SDH-deficient GISTs.

MISCIBILITY,CRYSTALLIZATION AND MECHANICAL PROPERTIES OF PPC/PBS BLENDS

In this paper, melt blends of poly（propylene carbonate） （PPC） with poly（butylene succinate） （PBS） were characterized by dynamic mechanical analysis （DMA）, differential scanning calorimetry （DSC）, tensile testing, wide-angle X-ray diffraction （WAXD）, polarized optical microscopy and thermogravimetric analysis （TGA）. The results indicated that the glass transition temperature of PPC in the 90/10 PPC/PBS blend was decreased by about 11 K comparing with that of pure PPC. The presence of 10% PBS was partially miscible with PPC. The 90/10 PPC/PBS blend had better impact and tensile strength than those of the other PPC/PBS blends. The glass transition temperature of PPC in the 80/20, 70/30, and 60/40 PPC/PBS blends was improved by about 4.9 K, 4.2 K, and 13 K comparing with that of pure PPC, respectively; which indicated the immiscibility between PPC and PBS. The DSC results indicated that the crystallization of PBS became more difficult when the PPC content increased. The matrix of PPC hindered the crystallization process of PBS. While the content of PBS was above 20%, significant crystallization-induced phase separation was observed by polarized optical microscopy. It was found from the WAXD analysis that the crystal structure of PBS did not change, and the degree of crystallinity increased with increasing PBS content in the PPC/PBS blends.

Current research and treatment for gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and have gained considerable research and treatment interest,especially in the last two decades. GISTs are driven by mutations commonly found in the KIT gene and less commonly in the platelet-derived growth factor receptor alpha gene,BRAF gene and succinate dehydrogenase gene. GISTs behave in a spectrum of malignant potential,and both the tumor size and mitotic index are the most commonly used prognostic criteria. Whilst surgical resection can offer the best cure,targeted therapy in the form of tyrosine kinase inhibitors(TKIs) has revolutionized the management options. As the first-line TKI,imatinib offers treatment for advanced and metastatic GISTs,adjuvant therapy in high-risk GISTs and as a neoadjuvant agent to downsize large tumors prior to resection. The emergence of drug resistance has altered some treatment options,including prolonging the first-line TKI from 1 to 3 years,increasing the dose of TKI or switching to second-line TKI. Other newer TKIs,such as sunitinib and regorafenib,may offer some treatment options for imatinib-resistant GISTs. New molecular targeted therapies are being evaluated,such as inhibitors of BRAF,heat shock protein 90,glutamine and mitogenactivated protein kinase signaling,as well as inhibitors of apoptosis proteins antagonist and even immunotherapy. This editorial review summarizes the recent research trials and potential treatment targets that may influence our future patient-specific management of GISTs. The current guidelines in GIST management from Europe,North America and Asia are highlighted.

Three-dimensional conformal intensity-modulated radiation therapy of left femur foci does not damage the sciatic nerve

During radiotherapy to kill femoral hydatid tapeworms, the sciatic nerve surrounding the focus can be easily damaged by the treatment. Thus, it is very important to evaluate the effects of ra- diotherapy on the surrounding nervous tissue. In the present study, we used three-dimensional, conformal, intensity-modulated radiation therapy to treat bilateral femoral hydatid disease in Meriones meridiani. The focus of the hydatid disease on the left femur was subiected to radio- therapy （40 Gy） for 14 days, and the right femur received sham irradiation. Hematoxylin-eosin staining, electron microscopy, and terminal deoxynucleotidyl transferase-dUTP nick end labeling assays on the left femurs showed that the left sciatic nerve cell structure was normal, with no ob- vious apoptosis after radiation. Trypan blue staining demonstrated that the overall protoscolex structure in bone parasitized with Echinococcus granulosus disappeared in the left femur of the animals after treatment. The mortality of the protoscolex was higher in the left side than in the right side. The succinate dehydrogenase activity in the protoscolex in bone parasitized with Echi- nococcus granulosus was lower in the left femur than in the right femur. These results suggest that three-dimensional conformal intensity-modulated radiation therapy achieves good therapeutic effects on the secondary bone in hydatid disease in Meriones meridiani without damaging the morphology or function of the sciatic nerve.

Sodium glucose co-transporter 2 inhibition reduces succinate levels in diabetic mice

BACKGROUND Type 1 diabetes(T1D) is associated with major chronic microvascular complications which contribute significantly to diabetes associated morbidity.The protein primarily responsible for glucose reabsorption in the kidney is sodium glucose co-transporter 2(SGLT2). Presently, SGLT2 inhibitors are widely used in diabetic patients to improve blood glucose levels and prevent cardiovascular and renal complications. Given the broad therapeutic application of SGLT2 inhibitors, we hypothesised that SGLT2 inhibition may exert its protective effects via alterations of the gut microbiome and tested this in a type 1 diabetic mouse model of diabetic retinopathy.AIM To determine whether the treatment with two independent SGLT2 inhibitors affects gut health in a type 1 diabetic mouse model.METHODS The SGLT2 inhibitors empagliflozin or dapagliflozin(25 mg/kg/d) or vehicle dimethylsulfoxide(DMSO) were administered to C57 BL/6 J, Akita, Kimba and Akimba mice at 10 wk of age for 8 wk via their drinking water. Serum samples were collected and the concentration of succinate and the short chain fatty acid(SCFA) butyric acid was measured using gas chromatography-mass spectrometry. Enzyme-linked immunosorbent assay(ELISA) was performed to determine the concentration of insulin and leptin. Furthermore, the norepinephrine content in kidney tissue was determined using ELISA. Pancreatic tissue was collected and stained with haematoxylin and eosin and analysed using brightfield microscopy.RESULTS Due to the presence of the Akita allele, both Akita and Akimba mice showed a reduction in insulin production compared to C57 BL/6 J and Kimba mice.Furthermore, Akita mice also showed the presence of apoptotic bodies within the pancreatic islets. The acinar cells of Akita and Akimba mice showed swelling which is indicative of acute injury or pancreatitis. After 8 wk of SGLT2 inhibition with dapagliflozin, the intermediate metabolite of gut metabolism known as succinate was significantly reduced in Akimba mice when compared to DMSO treated mice. In addition, empagliflozin resulted in suppression of succinate levels in Akimba mice. The beneficial SCFA known as butyric acid was significantly increased in Akita mice after treatment with dapagliflozin when compared to vehicle treated mice. The norepinephrine content in the kidney was significantly reduced with both dapagliflozin and empagliflozin therapy in Akita mice and was significantly reduced in Akimba mice treated with empagliflozin.In non-diabetic C57 BL/6 J and Kimba mice, serum leptin levels were significantly reduced after dapagliflozin therapy.CONCLUSION The inhibition of SGLT2 reduces the intermediate metabolite succinate, increases SCFA butyric acid levels and reduces norepinephrine content in mouse models of T1 D. Collectively, these improvements may represent an important mechanism underlying the potential benefits of SGLT2 inhibition in T1 D and its complications.

Quantitative analysis of 3-isopropylamino-1,2-propanediol as a degradation product of metoprolol in pharmaceutical dosage forms by HILIC-CAD

Aryloxypropanolamine is an essential structural scaffold for a variety of b-adrenergic receptor antagonists such as metoprolol.Molecules with such a structural motif tend to degrade into α,β ehydroxypropanolamine impurities via a radicaleinitiated oxidation pathway.These impurities are typically polar and nonchromophoric,and are thus often overlooked using traditional reversed phase chromatography and UV detection.In this work,stress testing of metoprolol confirmed the generation of 3-isopropylamino-1,2-propanediol as a degradation product,which is a specified impurity of metoprolol in the European Pharmacopoeia(impurity N).To ensure the safety and quality of metoprolol drug products,hydrophilic interaction chromatography(HILIC)methods using Halo Penta HILIC column(150mm×4.6 mm,5 μm)coupled with charged aerosol detection(CAD)were developed and optimized for the separation and quantitation of metoprolol impurity N in metoprolol drug products including metoprolol tartrate injection,metoprolol tartrate tablets,and metoprolol succinate extended-release tablets.These HILIC-CAD methods were validated per USP validation guidelines with respect to specificity,linearity,accuracy,and precision,and have been successfully applied to determine impurity N in metoprolol drug products.