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Biomedical subjects

X Su

Publications and source records attributed to X Su.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Endogenous uveitis in senior patients].

Forty-seven cases of endogenous uveitis aged 60 and above were analyzed in the retrospective study. The result shows males are more than females (1.2:1). Among the 47 cases, 28 cases (59.57%) are anterior uveitis, 18 cases (38.30%) are panuveitis. Only 1 case (2.13%) is posterior uveitis. Immediated-type uveitis is not found. Besides, 34 cases are non-granulomatosis type, more than the cases with granulomatosis type (13 cases). The major complications are secondary glaucoma (22 cases) and complicated cataract (16 cases). Immunological tests to the patients showed the unbalance of immune-regulation was mostly complicated by immune-related sickness. The cure rate was 40.58%. The invalid and deteriorative rate was 17.39%. 62.32% of the patients had the vision acuity lower than 0.3 after the treatment.

Aged↗
PubMed1992

Production of recombinant porcine tumor necrosis factor alpha in a novel E. coli expression system.

DNA sequences encoding porcine tumor necrosis factor alpha (TNF alpha) were reconstructed from a genomic-derived PCR product for expression in Escherichia coli. A synthetic DNA primer containing most of exon III was fused to exon IV sequences by means of PCR. The fused product was then inserted into the novel FLAG vector by restriction and ligation. This initial recombinant construct was propagated in single-strand form through use of a helper phage and subjected to oligonucleotide-directed mutagenesis for the purpose of introducing additional coding sequences from exons II and III. The final construct encoded a fusion protein consisting of the Omp-A signal peptide, a seven-amino acid FLAG peptide and the soluble form of porcine TNF alpha. Bacteria containing this construct produced a protein which was recognized by anti-FLAG monoclonal antibody in Western blots and which was purified by anti-FLAG immunoaffinity chromatography. The purified material was cleaved with enterokinase to remove the FLAG peptide. Both the enterokinase-cleaved form and the uncleaved form were shown to have TNF activity in a WEHI cell cytotoxicity assay.

Amino Acid Sequence↗
PubMed1991

A residue substitution in phosphoribulokinase of Synechocystis PCC 6803 renders the mutant light-sensitive.

We have isolated a light-sensitive mutant (BRLS) of the photosynthetic cyanobacterium Synechocystis 6803 (S. 6803) that does not survive exposure to bright light: 70% of BRLS cells die upon exposure to light of greater than 3,000 lux for 2 h. A complementing DNA fragment from wild-type cells and the corresponding DNA from the BRLS cells have been cloned and sequenced. An open reading frame is found to encode phosphoribulokinase, a key enzyme in the enzyme system for photosynthetic carbon reduction (ES-PCR). The deduced peptide sequence of this enzyme is highly homologous to eukaryotic phosphoribulokinases but is not similar to known prokaryotic phosphoribulokinases. The mutation responsible for the phenotype of BRLS is a single nucleotide change that results in substitution of phenylalanine for Ser-222 in the phosphoribulokinase. The catalytic activity and the apparent affinity for ATP of the mutated kinase are about one-tenth and one-seventh those of the wild-type kinase, respectively. Furthermore, the mutated kinase is selectively degraded in BRLS cells in bright light. Degradation of the mutated kinase and cell death in bright light can be suppressed by inhibiting photosynthetic electron flow (PS-EF) with 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The data indicate that PS-EF is not impeded by an impaired ES-PCR although the ES-PCR activity is controlled by the rate of PS-EF. Continued PS-EF in the absence of the normal substrates for carbon reduction appears to result in damage to cellular components essential for life or in the generation of lethal components.

Amino Acid Sequence↗
PubMed1991

[Effect of adenosine on carotid chemoreceptor activity in the rabbit].

The response of single carotid chemoreceptor afferent fibers upon adenosine acting on the carotid body (CB) was examined in 39 urethan-anesthetized rabbits. Totally 73 units with spontaneous discharge were recorded in our experiment. The results were as follows: (1) Of 55 units, 51 showed an increase in discharge frequency from 0.76 +/- 0.10 to 1.53 +/- 0.23 imp/s. A few new units were recruited concomitantly in response to intracarotid injection of adenosine (10 micrograms/kg). (2) Adding adenosine in the doses of 0.5, 1.5, 10, 50 and 100 micrograms/kg to the perfusate passing through the isolated carotid sinus led to dose-dependent increase in the discharge from 0.51 +/- 0.06 to 0.58 +/- 0.07, 0.78 +/- 0.13, 0.96 +/- 0.15, 1.11 +/- 0.17, 1.34 +/- 0.21 and 1.38 +/- 0.18 imp/s, respectively (P less than 0.001, n = 9 units). (3) In other 9 units with spontaneous discharge rate of 1.30 +/- 0.40 imp/s, the activity was decreased to 0.56 +/- 0.19 imp/s (P less than 0.01) by intracarotid injection of dopamine (50 micrograms/kg). Intracarotid injection of adenosine to the CB pretreated with dopamine still activated the units with an increase in firing rate to 1.07 +/- 0.28 imp/s (P less than 0.01). However, the increment was less prominent as compared with that of adenosine administration before dopamine injection (P less than 0.001). From the results obtained, it is hypothesized that the exciting effect of adenosine on the CB chemoreceptor may be attributed to its action on the presynaptic component of the chemoreceptor complex in attenuating the release of inhibitory transmitter dopamine, and its direct stimulating action on the chemosensory nerve endings.

Adenosine↗
PubMed1991

[Clinical observation of macular disease in patients with diabetic retinopathy].

The population was 65 cases (122 eyes) of diabetic macular disease. Background diabetic retinopathy was observed in 40 eyes, i.e., 32.80%. For the 82 eyes present proliferative diabetic retinopathy, i.e., 67.20%. According to Sigelmen's classification, 17 eyes were in stage I, i.e., 13.93% of the cases; 41 eyes were in stage II, i.e., 33.60% of the cases; 40 eyes were in stage III, i.e., 32.80% of the cases; 24 eyes were in stage IV, i.e., 19.67% of the cases. There were 122 eyes in this group. The visual acuity of 66 eyes showed > or = 0.3, i.e., 54.00%, while that of 56 eyes showed 40.3 i.e. 46.00%. Nearly half patients showed low visual acuity and loss of vision. This result was responsible for the cases who were at the late stage of diabetic and with a long history of diabetic or the diabetic was poorly controlled. So the writer appeal to ophthalmologists and physicians to prescribe the effective guides to all the diabetic patients. We suggest that it is important that dynamic observation be carried out of hemorhelological manifestation and early treatment diabetic retinopathy for the clinical prevention and treatment of diabetic retinopathy.

Adult↗
PubMed1991

[Methods of cryopreservation of pollen in Fritillaria thunbergii Miq].

The effects of cryomethods, cryoprotectants, pollen age and pollen water content on the viability of pollen in Fritillaria thunbergii after cryopreservation were studied. The viability came highest (56.4%) when pollen of the flowering day (20% pollen water content) was treated by step-cooling. Hybridization in the fields showed that cryopreserved pollen could go to seed as well.

Cryopreservation↗
PubMed1991

[Effects of intracarotid injection of adenosine on respiration blood pressure and renal sympathetic nerve activity].

Changes of mean arterial pressure (MAP), heart rate (HR), respiration and renal sympathetic nerve activity (RSNA) induced by close-arterial administration of adenosine to carotid body (CB) were observed in 33 anesthetized rabbits. The results were as follows: (1) In response to intracarotid injections of adenosine, MAP decreased in a dose-dependent manner, while the frequency of respiration increases with little change in depth. Following carotid sinus denervation, intracarotid injection of adenosine still resulted in a decrease of MAP but with no changes in respiration. (2) By adding adenosine to perfusate of the isolated carotid sinus, both MAP and HR decreased, but these effects could be abolished by inactivation of carotid body. (3) MAP decreased and RSNA enhanced during perfusing adenosine into carotid sinus. These effects could be abolished by the section of sinus nerve or inactivation of CB. From the results obtained, it is considered that adenosine is capable of activating CB, decreasing MAP and heart rate but with a concomitant increases in respiration and RSNA.

Adenosine↗
PubMed1991

[Determination of seed activity of Fritillaria thunbergii Miq].

This paper presents a quantitative determination of the seed activity of Fritillaria thunbergii. The result shows that the optical density (O. D.) of highly active seeds is 0.241-0.247, of lowly active seeds is 0.171-0.192 and of inactive seeds is 0.005-0.006.

Medicine, Chinese Traditional↗
PubMed1990

Induction of cytosine-rich poly(A)+ RNAs in Chlamydomonas reinhardtii by cell wall removal.

RNA accumulation in Chlamydomonas reinhardtii during the course of wall regeneration in protoplasts prepared by treatment of vegetative cells with autolysin was studied. In vitro translation of poly(A)+ RNA isolated from wall-regenerating cells indicated that cell wall removal induced the accumulation of several large RNA transcripts. Some of these induced RNAs were enriched following oligo(dG)-cellulose chromatography (referred to as cytosine-rich). The induced and cytosine-rich poly(A)+ RNAs potentially code for hydroxyproline-rich cell wall glycoproteins (HRGPs). Immunoprecipitation of in vitro translated products with an antiserum against a deglycosylated wall fraction (2BII) confirmed that these RNAs contained species involved in cell wall biosynthesis.

Blotting, Northern↗
PubMed1990

[Comparative analysis of alkaloid components in cultured and planted Pinellia ternata (Thunb.) Breit].

This article presents a study on the comparative analysis of alkaloid components in cultured and planted Pinellia ternata by TLC and TLCS. It was found that their absorption spectra were identical and their chromatograms were very similar to each other. The content of total alkaloid was 0.48% (cultured) and 0.137% (planted). The relative contents of other components in percentage (cultured/planted) were 116.14, 34.47, 83.82, 93.12, 101.79, and 121.73% respectively.

Alkaloids↗
PubMed1990

[Determination of tangshenoside I in Codonopsis pilosula Nannf. by TLC-UV spectrophotometric method].

A method of thin layer chromatographic separation and ultraviolet spectrophotometric determination of tangshenoside I in Codonopsis pilosula is described. A comparison of the contents in various samples is made. The contents of tangshenoside I in frosted sample have been found to be twice as much as in normal drug. The recovery of tangshenoside I is 99.92% and the coefficient of variation of eight samplings is 1.77%.

Chromatography, Thin Layer↗
PubMed1990

[Membrane component of Shigella flexneri and their relationship to bacteria antigenicity and virulence].

Our previous works have shown that membrane proteins of S. flexneri can elicit protection against the bacteria in vivo. In this study, we further, using human convalescent sera (HCS) from adult patients infected with S. flexneri, investigated the relationship between membrane components of S. flexneri and their antigenicities and virulences. It was shown in immunoblotting that 5 virulent strains of S. flexneri and avirulent strain T32 derived from S. flexneri 2a by Istrati in Romania and used as a live vaccine, had three common proteins bands formed by the components of MW 67 kD, 63 kD and 60 kD with either HCS from patients infected with S. flexneri 2a and 3a or HCS absorbed by an avirulent variant strain 24570 of S. flexneri 2a, while virulent strains M90T and M25-8A (pWR110)minI shown another two bands of Mw 78 kD and 35 kD respectively. In contrast, no band was found with strain 24570. HCS from patients infected with S. flexneri 1a, 2a and 3a as well as those HCS absorbed by 24570 had blocking effect on the invasiveness of virulent strain of S. flexneri to the kerato conjunctiva of guinea pigs; nevertheless, HCS absorbed by T32 lost the blocking effect accompanied by disappearance of 67 kD, 63 kD and 60 kD components when T32 was used as antigen indicating that 67 kD, 63 kD and 60 kD membrane components of S. flexneri may account for the antigen of S. flexneri eliciting protection antibodies in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A method for RNA isolation from marine macro-algae.

Sulfated, carboxylic polysaccharides and polyphenols found in marine macro-algae interfere with RNA isolation from these plants and inhibit RNA activities in vitro. Methods based on differential precipitation of RNA or carbohydrates in high salts were used to eliminate the acidic carbohydrates. To protect RNA from inactivation by oxidized polyphenols, strong reducing reagents were used to prevent polyphenol oxidation. RNA was successfully isolated from Macro-cystis pyrifera (brown alga), Porphyra schizophylla (red alga), and Enteromorpha intestinalis (green alga). mRNA isolated from the total RNA was shown to be translationally active.

Carbohydrates↗
PubMed1987

A refined method for silver staining of nucleic acids fixed on nitrocellulose.

A refined silver staining method was developed to stain nucleic acids fixed onto nitrocellulose membranes and nylon-based membranes. Approximately 4 ng RNA or DNA can be stained with this method with no protein interference. This method involves simple repetition of immersions of membranes in three solutions prepared from common chemicals. The total staining time is less than 30 min.

Collodion↗