Production and antigenicity analysis of a recombinant insulinoma associated protein-2 in HEK293 cells / 生物工程学报

Insulinoma-associated protein-2 (IA-2) is a transmembrane glycoprotein belonging to the tyrosine phosphatase-like protein family as well as an important autoantigen in the diagnosis of type 1 diabetes. IA-2 products have been marketed in Europe and the United States. At present, commercially available IA-2 antigens are either the recombinant IA-2ic domain or the IA-2 naturally extracted from bovine islets. However, the recombinant IA-2 antigen displays weak positive in clinic practice, which often results in occasional detection failures, thus cannot completely replace the naturally extracted IA-2 antigen. In this study, an HEK293 expression system was used to explore the production of recombinant IA-2. An IA-2 transmembrane fragment (IA-2 TMF) located at amino acid position 449-979, also known as the natural membrane protein form of IA-2, was produced in HEK293 through transfection, and both the expression conditions and dissolution conditions of the membrane protein were also optimized. The purified membrane protein yield was 0.78 mg/L cell culture. Subsequently, the antigen activity of IA-2 TMF was compared with RSR rhIA-2 through enzyme linked immunosorbent assay. The serum of 77 type 1 diabetes patients and 32 healthy volunteers were detected. Receiver operating characteristic curve (ROC) curve was used to characterize the sensitivity and specificity of the test results. The results showed that the sensitivity of IA-2 TMF was 71.4% (55/77), while the sensitivity of RSR rhIA-2 was 63.6% (49/77), and the specificity of both antigens were all 100%. There was no significant difference in specificity between the two antigens, but the sensitivity of IA-2 TMF was appreciably better than that of the imported gold standard RSR rhIA-2 antigen. In conclusion, the recombinant IA-2 TMF produced in HEK293 cells can be used as a raw material to develop in vitro diagnostic reagents for type 1 diabetes.

Analysis of a family with early-onset dementia caused by a new mutation in the triggerring receptor expressing on myeloid cells 2 gene / 中华神经科杂志

Objective:To analyze the clinical phenotype, imaging characteristics and genetic characteristics of a family of early-onset dementia caused by a new mutation in the triggerring receptor expressing on myeloid cells 2 gene (TREM2).Methods:Clinical data were collected from a patient with early-onset dementia. Then whole exome sequencing was performed for the proband, followed by Sanger sequencing for the family members.Results:The clinical manifestations of the proband (a 49-year-old female) was personality changes, mental and behavioral abnormalities, memory loss, ataxia, and seizures. Whole-exon sequencing revealed a novel homozygous mutation in exon 2 of TREM2, namely c.154C>T (p.R52C) heterozygosity in four family members, and one patient with similar clinical manifestations was deceased. The proband′s brain magnetic resonance imaging showed bilateral frontotemporal atrophy, bilateral white matter hyperintensity, thin corpus callosum. No bone cysts of the hands and feet were found by digital radiographic imaging.Conclusions:A homozygous mutation in TREM2 gene was detected in a patient with frontotemporal dementia-like dementia, epilepsy, but without bone cysts. This mutation is probably pathogenic. This research highlights the importance of TREM2 gene mutation screening in early-onset dementia, especially in those with atypical presentations.

Clinical analysis of 11 cases of autoimmune encephalitis with antibodies against contactin-associated protein-like 2 / 中华神经科杂志

Objective To explore the clinical features,auxiliary examinations,therapies and prognoses of patients with antibodies against contactin-associated protein-like 2 (CASPR2).Methods The clinical data of 11 anti-CASPR2 encephalitis patients who were admited to the People's Hospital of Zhengzhou University from March 2015 to April 2018 were retrospectively analyzed.Results The age of these 11 cases was (35.6± 19.4) years (ranged 20-74 years),and eight cases were females.There were seven cases with limbic encephalitis which included six cases of epilepsy,four cases of memory impairment,two cases of mental and behavioral abnormalities.Four cases had peripheral nerve hyperexcitability.Four cases had neuropathic pain.There were six cases with autonomic dysfunction including five cases of constipation,three cases of tachycardia,two cases of hyperhidrosis,two cases of urinary disorder.Seven cases had sleep disorder.Four cases had weight loss.Two cases showed cerebellar symptoms and two cases had hyponatremia.Magnetic resonance imaging scan of the brain showed abnormal signal in two cases,mainly involved medial temporal lobe and the hippocampus.Six cases underwent 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) examination,and three cases showed abnormalities,including two with temporal hypermetabolism and one with cortical hypermetabolism.Chest enhanced CT and PET-CT showed thymoma in one case.All cases received immunotherapy,and after treatment their symptoms were improved.Long-term follow-up was performed in nine cases,and three cases relapsed.Conclusions The major clinical manifestations of anti-CASPR2 encephalitis were limbic encephalitis,peripheral nerve hyperexcitability,neuropathic pain,autonomic dysfunction,insomnia and so on.Immunotherapy was effective and some patients may have recurrence.

CADASIL with clinical manifestations of baldness, lumbago and Parkinson's symptoms / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate a cerebral autosomal dominant arteriopathy with the subcortical infarcts and leukoencephalopathy (CADASIL) case with clinical manifestations of baldness, lumbago and Parkinson's symptoms.</p><p><b>METHODS</b>Clinical and imaging data of the patient were analyzed. The patient and his family members were also subjected to genetic testing.</p><p><b>RESULTS</b>The symptoms of the patient included recurrent stroke, dementia, and mood disturbance, in addition with lumbago, baldness and Parkinson's symptoms but no migraine. Cranial MRI of the patient showed bilateral symmetric leukoencephalopathy and multiple small subcortical lacunar infarcts. A point mutation in exon 11 of the NOTCH3 gene (R558C) was discovered in the proband and four asymptomatic relatives.</p><p><b>CONCLUSION</b>CADASIL is characterized by recurrent subcortical ischemic stroke, dementia, pseudobulbar palsy, and mood disturbance. Baldness, lumbago and Parkinson's symptoms may also be seen in such patients.</p>

Presenilin 1 gene mutation p.L226R in a Chinese early-onset familial Alzheimer's disease pedigree / 中华神经科杂志

Objective To analyze the clinical presentation , the mutation of the pathogenic genes and imaging features in a Chinese Han early-onset Alzheimer's disease pedigree.Methods A pedigree of Alzheimer's disease was collected.The DNA sequence of presenilin 1 (PSEN1), presenilin 2, micro-tubule associated protein tau ,β-amyloid precursor protein gene was analyzed , the clinical presentation , results of accessory examination , neuropsychological evaluation of the proband were investigated and the point mutations of some members of the family , 50 sporadic Alzheimer's disease patients , 50 normal controls were verified.Results The proband of the family appeared as language impairment , memory loss, personality change, repeated language, visuospatial impairment, mental and behavior disorder.The gene detection showed p.L226R mutation in the condon 226 in the exon 7 of PSEN1 gene of the proband and five other family members (Ⅲ1 ,Ⅲ2 ,Ⅲ4 ,Ⅲ6 ,Ⅲ7 ).The mother of the proband had the suspicious symptoms , and the sister and the brother of the proband had the similiar symptoms with the proband , all of whom died.Fifty sporadic Alzheimer'disease patients and 50 unrelated normal subjects did not have the mutation .The computed tomographic angiography showed that the brain blood vessels were normal and 18 F-fludeoxyglucose positron emission tomography (18F-FDG-PET) showed brain atrophy and hypometabolism in frontotemporal regions, parietal regions, hippocampal areas, however, the MRI, MRA and 18F-FDG-PET of the two mutation carriers (Ⅲ6 ,Ⅲ7 ) were all normal.Conclusion We reported a novel mutation in an early-onset Alzheimer's disease family presented as language impairment in the early stage of the disease , the p.L226R mutation of PSEN1, which may be a pathogenic mutation to cause the family's dementia.

Extracellular sialidase degrades sialic acid in recombinant human erythropoietin produced by an industrial Chinese hamster ovary cell strain / 生物工程学报

To investigate the N-glycosylation characteristics of recombinant human erythropoietin (rhEPO) produced by an industrial Chinese hamster ovary (CHO) cell line that is currently used in a large scale manufacturing process, we cultured this cell strain in static mode. The produced rhEPO in the culture supernatant was analyzed using isoelectric focusing (IEF) and Ricinus communis agglutinin-I (RCA-I) lectin precipitation. The lactate dehydrogenase (LDH) and sialidase activity in the serum-free supernatant were assayed as well. The analyses revealed that this cell strain could produce rhEPO with high sialic acid content, but during prolonged culture, cell viability decreased with time whilst the activity of sialidase present in the supernatant increased. The loss in rhEPO quality was due to a decrease in terminal sialic acid on the N-glycans, caused by sialidase degradation. The methods and findings in this paper serve as basis for further investigation of industrial production process.

Transient gene expression of soluble VEGFR2: I-IV / 生物工程学报

The extracelluar domain I-IV of target gene VEGFR2 (Vascular endothelial growth factor receptor 2) was cloned from villus of trimester abortion by RT-PCR, and linked to the expression vectors. Then, the transfection conditions were optimized in serum-free suspension culture HEK293 using GFP (Green fluorescence protein) as the report gene. The results showed that the optimal transfection efficiency and cell number were obtained when the ratio of foreign DNA: PEI = 1:2 (W/W), DNA = 1.5 g /10(6) cells and shaking speed (120 r/min) in serum free medium in the beginning 4 hours of transfection. After optimizing the transfection conditions, the expression vector was successfully constructed for transient gene expression in HEK293, COS-7, and CHO-K1. The result shows that the target protein was only detected in CHO-K1 supernatant. Because of the C-terminal 8-His tag of target protein, target protein was subsequently purified using Ni2+-IDA and 5 mg purified protein was obtained in 1.5 L supernatant of CHOK1.

Optimization of Hospital Inventory Management of Expensive Drugs / 中国药房

OBJECTIVE:To scientifically establish the variety scope of expensive drugs and to reduce the stock level to a maximum degree under the premise of supply security. METHODS: The variety scope of expensive drugs was established by modified ABC (activity-based costing) analytical method,and the management on expensive drugs was carried out by fixed-quantity system (FQS) together with fixed-interval system (FIS). RESULTS: The practice of the optimized management effectively reduced the stock quantity of expensive drugs,increased the amount of money of 75 stocked drugs to 2.473 7 million yuan from 3.935 7 million yuan;the turnover rate rose from 238.36% to 461.86%,and the turnover days were decreased from 13.03 days to 8.29 days. CONCLUSION: Computer management in combination with the modified ABC analytical method together with FQS and FIS management led to an effective and accurate inventory management of expensive drugs,which then resulted in a speedy turnover rate,decreased fund occupying and lowered drug cost.