Biomedical subjects

A Ji

Publications and source records attributed to A Ji.

11 recordsLinked to original sources

PubMed2005

MRI findings of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis.

AIM: To study the imaging characteristics of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis using magnetic resonance imaging (MRI). MATERIALS AND METHODS: Seventeen MRI examinations of the brain and spinal cord in five patients with angiostrongyliasis cantonensis of the central nervous system were performed. The final diagnosis was based on typical clinical symptoms, results of blood and cerebrospinal fluid (CSF) tests, and the presence of nematode larvae in the CSF. The sequential MRI follow-up examinations were carried out at a different stage for every patient from 1 to 28 weeks after the onset of symptoms. The features of the lesions in the brain, spinal cord, meninges and nerve roots on MRI were studied, moreover, the development of the lesions was analysed on follow-up MRI. RESULTS: Abnormalities were demonstrated on MRI in all five cases. They included three cases of meningoencephalitis, one case of encephalitis and one myelomeningitis. The locations and appearances of the lesions were as follows: (1) brain involvement in four cases (including cerebrum in four, cerebellum in two and brain stem in three), and spinal cord involvement in one case. These lesions were diffuse or scattered and appeared as similar or slightly reduced signal intensity on T1-weighted images (T1WI), high signal intensity on T2-weighted images (T2WI) and turbo fluid attenuated inversion recovery pulse sequence (FLAIR) images. After administration of gadolinium chelate (Gd-DTPA), multiple round or oval enhancing nodules, with diameters ranging from 3 to 10 mm, were seen on T1WI, a few lesions appeared as stick-shaped enhancement whose longest measurement was 14 mm. Diffuse or local oedema around the lesion could be seen. (2) Meningeal involvement in four cases, a case of ependymal involvement and a case of nerve root involvement were among them. These lesions appeared as linear or nodular enhancement of the leptomeninges and ependyma, as well as nerve root enhancement. (3) There was a mild ventricular enlargement in two cases. On follow-up MRI lesions were most severe from the 5th week to the 8th week and it took at least 4-8 weeks (1-2 months) for a lesion to resolve completely, the resolution of larger lesion needed more than 22 weeks. CONCLUSION: Multiple enhancing nodules in the brain and linear enhancement in the leptomeninges were the main features; stick-shaped enhancement was the characteristic sign of the disease on Gd-DTPA enhanced-T1 weighted images.

Adult↗

PubMed2001

Substrate selectivity of Gluconobacter oxydans for production of 2,5-diketo-D-gluconic acid and synthesis of 2-keto-L-gulonic acid in a multienzyme system.

Substrate selectivity of Gluconobacter oxydans (ATCC 9937) for 2,5-diketo-D-gluconic acid (2,5-DKG) production was investigated with glucose, gluconic acid, and gluconolactone in different concentrations using a resting-cell system. The results show that gluconic acid was utilized favorably by G. oxydans as substrate to produce 2,5-DKG. The strain was coupled with glucose dehydrogenase (GDH) and 2,5-DKG reductase for synthesis of 2-keto-L-gulonic acid (2-KLG), a direct precursor of L-ascorbic acid, from glucose. NADP and NADPH were regenerated between GDH and 2,5-DKG reductase. The mole yield of 2-KLG of this multienzyme system was 16.8%. There are three advantages for using the resting cells of G. oxydans to connect GDH with 2,5-DKG reductase for production of 2-KLG: gluconate produced by GDH may immediately be transformed into 2,5-DKG so that a series of problems generally caused by the accumulation of gluconate would be avoided; 2,5-DKG is supplied directly and continuously for 2,5-DKG reductase, so it is unnecessary to take special measures to deal with this unstable substrate as it was in Sonoyama's tandem fermentation process; and NADP(H) was regenerated within the system without any other components or systems.

Gluconates↗

PubMed2000

Cloning and expression in Pichia pastoris of a genetically engineered single chain antibody against the rat transferrin receptor.

The present investigation describes the construction of a genetically engineered single chain antibody (scFv) against the rat transferrin receptor (OX26), and demonstrates that this scFv antibody can be fully processed and expressed as a soluble secreted molecule in the methylotrophic yeast Pichia pastoris. Restriction endonuclease sites located at both 5'- and 3'-flanking regions of OX26 coding region in the prokaryote pOPE-OX26 vector were engineered to incorporate yeast compatible restriction endonuclease sites (i.e. EcoRI and SmaI or AvrII). The modified OX26 cDNA was subcloned into the Pichia expression vectors pPIC9 and pHIL-S1. An OX26 scFv high producer clone [GS115 His+ Mut+ (pPIC-OX26 SacI)] was isolated and used for large-scale production and characterization. Because the engineered scFv contains both a c-myc tag and a (His)5 tail, the OX26 scFv was purified to homogeneity by immobilized metal affinity chromatography. The identity of the OX26 scFv was confirmed by Western blot analyses with both anti c-myc and anti poly-His antibodies. Minor immunoreactive bands corresponding to hyperglycosylated and partially processed alpha-factor leader prosequence were also detected in the purified OX26 scFv, and these contaminants were markedly reduced when the expression of the OX26 scFv was performed in minimal methanol medium buffered with phosphate at pH = 7. The present investigation suggests that this expression system may be useful for the production of anti-receptor single chain antibodies that can be used as brain drug delivery vectors.

Antibodies↗

PubMed1999

Properties of acetylcholine receptor ion channels in the acutely dissociated neurons of the marginal division in the rat striatum.

Cell-attached mode of patch clamp technique was employed to investigate the properties of acetylcholine (ACh)-induced ion channels in acutely dissociated neurons from the marginal division (MrD) of rat striatum. Two types of conductance states (25 pS and 60 pS) were recorded. The 25 pS channel (more than 80%) was the main type in the neurons of MrD and was described here. The amplitudes of inward currents increased with hyperpolorization and the reversing potential was about 0 mV. Both single short opening and long burst openings were observed in MrD neurons. Two-time constants of these two kinds of ion channels are 0.29 ms, 1.84 ms and 1.96 ms, 18.24 ms, respectively. Average close time can be fitted with two exponential functions, the two time constants are 1.7 ms and 54 ms. Probability of channel opening is about 0.012 and no voltage-dependence was found. The properties of reversing potential, voltage-independence and the form of agonist to the ion channels indicated that the recorded channel currents flow through AChR channels. The mAChR is involved in slow synaptic transmission and Ach can not induce the opening of mAChR ion channel. The binding site of ACh to AChR and the nAChR ion channel are the same protein, ACh can only activate nAChR ion channel directly. Therefore, the recorded ion channels in the present study are nAChR ion channels. The results suggest that nAChR ion channels exist in the neurons of MrD and the MrD probably is involved in learning and memory mechanism of the brain.

Acetylcholine↗

PubMed1999

[Changes of surface roughness and glossiness of the composite resins during polishing].

OBJECTIVE: To investigate the changes of surface roughness and glossiness of the composite resins during polishing. METHODS: Nine conventional composite resins were evaluated. Composite specimens were polymerized on celluloid strip, so, smooth surfaces were obtained for each specimen, then the smooth surface of the specimens were sequentially polished with diamond polishing papers grits #240, #320, #400, #600, #800 and #1200. The roughness and glossiness of the central surface at 60 degrees reflex angle were measured. RESULTS: The results showed that the values of roughness decreased steadily when specimens were polished with sequential polishing paper from coarse to fine one. A further polishing with grit #800, the values of roughness resumed to the pre-polishing values in all the composite specimen. The change of values of glossiness is very small within polishing with #240-#600. A further polishing with grit #800 and #1200, the values of glossiness increased jumpily. The values of glossiness of five composite resins reached or surpassed the level of pre-polishing. CONCLUSION: This study indicates that fine surface would not be gained until the composite resins were polished with grit #800 and #1200 polishing paper.

Composite Resins↗

PubMed1999

[Clinical and experimental study on treatment of Helicobacter pylori infected gastritis by xialian yiyou capsule].

OBJECTIVE: To observe the therapeutic effect of Xialian Yiyou Capsule (XLYYC) on helicobacter pylori (HP) infected gastritis to develop the serial Chinese classical recipe. METHODS: HP infected patients were divided into two groups, 136 patients in the XLYYC group treated with XLYYC and 90 patients in the control group treated with Lizhu Dele Capsule, for 4 weeks as one therapeutic course, the clinical therapeutic effect was observed, and corresponding animal experiments were done. RESULTS: Clinical effect of the XLYYC group was better than that of the control group in improving clinical symptoms, relieving inflammation of gastric mucosa and eliminating HP (P < 0.05, P < 0.01). Results of animal experiment showed that XLYYC was superior than the control significantly in anti-inflammation, analgesia, stomach emptying and curing gastric ulcer model (P < 0.05, P < 0.01). Without any adverse reaction has been found in acute toxicologic study. CONCLUSION: The therapeutic effect of XLYYC in treating HP infected gastritis was definite and safe, non-toxic.

Adolescent↗

PubMed1999

[FPMULTI--a software for multi-layer composition and thickness analysis and its applications].

Main features of FPMULTI, a software for analyzing composition and thickness of multi-layer samples simultaneously using XRF, are briefly described in this paper. Based on fundamental parameter method, the software has the capability of determining multi-layer samples containing up to 10 layers and 25 elements. Calibration standards can be bulk or multi-layer of pure element or multi-element standards. Application examples for tin-plates, hot dip galvanized zinc-plates and 'fingerprint-resistant' plates were given. FPMULTI is used to predict the relationship between intensities of different X-ray lines and the thickness first and then to analyze those samples. When using only few calibration standards, the results from FPMULTI are much better than those from linear regression method, and this reflects the advantages of the fundamental parameter approach.

English Abstract↗

PubMed1999

[Neural cluster structure with single component prediction in multiple variable systems for X-ray fluorescence spectrometry].

A neural cluster structure with single component prediction (NCSCP) was proposed for X-ray fluorescence spectrometry in a multivariable system. The neural cluster structure is built by the collection of a group of neurons which have close relationships among one another. In X-ray fluorescence analysis, the structure is constructed by choosing the elements in which there exist serious matrix effects, and deleting the components containing large noise. The predictability of the neural cluster structure was compared with that of the classical backward error propagation algorithm with single component prediction. The results show that the neural cluster structure is significantly superior to the classical algorithm in prediction accuracy, antidisturbance and the predictabilty to outliers.

English Abstract↗

PubMed1998

[Study on chemical components of Momordica charantia].

The paper deals with the study of chemical constituents of the unmatured fruits of Chinese traditional medicine Momordica charantia L. which is usually used as green-stuff. There are two parts of the extracts obtained by ethanol precipitation, and four compounds obtained from the further isolation. They are identified as Vincine, Mycose, Momordicoside A and Momordicoside B.

Drugs, Chinese Herbal↗

PubMed1997

[Clinical evaluation for wear of composite resin in filling of molars].

To study the best evaluation method for wear of composite resins, 93 occlusal cavities of molars were restored with four kinds of light-cured composite resins, and three-year clinical research of wear analyses was performed using either direct evaluation method (USPHS) or indirect cast comparison (Leinfelder) method. The results suggested that the direct evaluation method for early wear of restorations would be less sensitive, but it remains the preferred system for the evaluation otherwise; the indirect method would be more reliable and sensitive, and numerical estimates of wear are more readily suitable for statistical analysis. The combination of direct and indirect methods will evaluate composite resin wear objectively and comprehensively.

Adolescent↗

PubMed1996

[Clinical evaluation about restoration for cervical wedge-shaped defects of teeth using composite and dentin bonding].

100 cervical wedge-shaped defects of teeth with normal pulp from 19 patients were restored with light cure composite (durafill). For each patient, teeth of one side were experimental group, the other side were the control group, and left or right side was alternatively changed randomly. For the experimental group, the restorations of 49 teeth were adhered by Gluma dentin bonding. For the control group, the restorations of 51 teeth were adhered by Durafill bonding. The results of 2 years follow-up study with modified USPHS evaluation criterion indicate that curative effects, including retention and marginal sealing in the experimental group are much better than those in the control group.

Composite Resins↗