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Biomedical subjects

L Wu

Publications and source records attributed to L Wu.

At least 577 records · Page 32Linked to original sources
PubMed1995

Two regions of GLUT 2 glucose transporter protein are responsible for its distinctive affinity for glucose.

The glucose transporter in the hepatocyte and pancreatic beta-cell (GLUT 2) has a lower affinity for glucose than other members of the glucose transporter family. To investigate the molecular mechanism for the distinctive affinity of GLUT 2 for glucose, we expressed chimeric GLUT 2 and GLUT 4 proteins in Xenopus oocytes and measured 3-O-methyl-D-glucose transport. In the oocyte system, GLUT 2 had a Km of 31.8 +/- 2.8 mM for 3-O-methyl-D-glucose, whereas GLUT 4 had a Km of 7.2 +/- 2.4 mM under equilibrium exchange conditions. GLUT 4/GLUT 2 chimera that contained the intracellular loop and transmembrane domains 7-12 of GLUT 2 (amino acids 239-497) had a Km similar to that of wild-type GLUT 2. A GLUT 4/GLUT 2 chimera in which the COOH-terminal 30 amino acids of GLUT 4 were replaced with the corresponding region of GLUT 2 had a 2-fold higher Km than GLUT 4, but still had a much lower Km than GLUT 2. These results indicate that both transmembrane domains 7-12 and the COOH-terminus of the protein are responsible for the distinctive glucose affinity of GLUT 2.

Animals↗
PubMed1995

Effects of oxygen on wound responses to growth factors: Kaposi's FGF, but not basic FGF stimulates repair in ischemic wounds.

Kaposi's fibroblast growth factor (K-FGF, FGF-4) is a newer member of FGF family with uncharacterized wound healing properties. Basic fibroblast growth factor (bFGF, FGF-2) has been well studied and accelerates repair in normal and impaired wound healing models. K-FGF and bFGF are known to have similar biological effects in tissue culture, and both stimulate fibroblast and endothelial cell proliferation. The rabbit dermal ulcer model was used to examine the effects of bFGF and K-FGF under ischemic and nonischemic conditions. We found bFGF was ineffective in stimulating healing under ischemic conditions even at high doses (30 micrograms/wound). However, when the ischemic wounds were treated with bFGF (5 micrograms/wound) plus hyperbaric oxygen therapy, it was highly effective again as previously found under nonischemic conditions (P < 0.05). In contrast K-FGF stimulated repair in both nonischemic and ischemic wounds (P < 0.05). These results suggest that wound oxygen content differentially regulates responsiveness to bFGF and that K-FGF is biologically active in hypoxic wounds.

Animals↗
PubMed1995

[Study on determination of gentamycin in serum by enhanced chemiluminesent immunoassay based on immobilized antibody and biotin-avidin system].

Gentamycin was determined by competition with biotin labeled gentamycin in the presence of an immobilized antibody to gentamycin. Microcrystalline cellulose was first coupled with sheep anti-rabbit antibody, then the anti-gentamycin antibody was conjugated and the competition reaction conducted. After separation, HRP-avidin was added to the precipitation and the amount of HRP conjugate determined by enhanced chemiluminescene. The limit of detection for gentamycin in serum was 63-78 ng/tube and the average recovery of gentamycin 103%. The correlation coefficient of the log-log regression equation. Magnitude of r was 0.991 +/- 0.006.

Animals↗
PubMed1995

The effects of passive antiviral immunotherapy in AKR mice: I. The susceptibility of AKR mice to spontaneous and induced T cell lymphomagenesis.

The AKR inbred mouse strain displays a high incidence of spontaneous T cell lymphomas that arise predominantly in the thymus of 6 to 12-month-old mice. Heterogenous nonacute transforming retroviruses are associated with the etiology of the disease: the endogenous ecotropic viruses (inherited in AKR mice at two non-linked chromosomal loci, Akv-1 and Akv-2), the xenotropic virus and recombinant viruses. Prevention of spontaneous T cell lymphomagenesis in AKR mice by passive anti-viral immunotherapy was accomplished by suppressing endogenous ecotropic virus release. Treatment with monoclonal antibody Hy-72 reacting only with Akv1 type ecotropic viruses, or with mAb 18-5 with specificity for both ecotropic and MCF recombinant virus envelope glycoprotein (administered from birth for 10 days) inhibited similarly T cell lymphoma development. A reduced thymus cellularity observed in these mAb treated mice coincided with reduced level of earliest intrathymic low CD4 precursor population in their thymus. The role of endogenous viruses (MuLV) and presence of potential lymphoma cells (PLCs) (identified among bone marrow cells of untreated AKR mice) in enhanced T cell lymphomagenesis in AKR mice, triggered by different leukemogenic agents, was evaluated. Intrathymic injection of the radiation leukemia virus variant A-RadLV or administration of methylnitrosourea resulted in a high lymphoma incidence within a short latent period of 80-100 days irrespective of the presence or absence of MuLV or PLCs in these treated mice. Thus, a direct action of these agents on thymocytes seems to occur. The high susceptibility of untreated AKR mice to radiation induced T cell lymphomagenesis was not affected by pretreatment with mAb Hy-72; in contrast to markedly reduced sensitivity following pretreatment with mAb 18-5 (15 vs 100%). The mAb 18-5 induced resistance to radiation lymphomagenesis seems to be related to defects in the bone marrow stem cell pool as well as in the thymus microenvironment of mAb 18-5 treated mice. Thus, different developmental pathways are involved in enhanced T cell lymphomagenesis in AKR mice.

Animals↗
PubMed1995

[Significance and detection of insulin-like growth factor I in vitreous with proliferative retinal diseases by radioimmunoassay].

The insulin-like growth factor I (IGF-I) levels in 67 vitreous samples taken from 57 patients with various proliferative retinal diseases and 10 normal subjects were detected by radioimmunoassay (RIA). The acid-ethanol-extracted (AEE) method was used to remove the IFG-binding protein before the detection. Our results revealed that IGF-I levels were increased to varying extents in these patients' vitreous. The IGF-I levels in the vitreous with proliferative diabetic retinopathy (PDR) and central retinal vein occlusion (CRVO) were significantly higher than those of the controls. In the PDR group, the increased IGF-I level in the vitreous was positively correlated with the level in serum. The increased IGF-I level in vitreous may play an important role in the development and pathogenesis of proliferative retinal diseases. Great differences were found between the native and the AEE treated vitreous, suggesting that the binding protein posed an obvious interference on the detection of IGF-I by RIA.

Adolescent↗
PubMed1995

[Morphometric study on the cerebral cortex of partial status epilepticus rats induced by coriaria lactone].

Twenty adult male Wistar rats, divided into two groups were studied. Experimental rats were embedded with a particle containing Coriaria Lactone into the fore limb's representative area of cerebral motor cortex to induce epilepsy. Control rats were embedded with a particle containing distilled water. After 6 h motor cortex was cut and the structure was compared morphologically with control rats. Some pale neurons, dark shrunken neurons and severe sponginess of neuropil were observed in layers I-V of the epileptic rat under LM. Under EM, the mitochondria became swollen and other organelles migrated and close associated with the nucleus in pale neurons, and in dark neurons both cytoplasm and karyoplasm showed highly electron dense. The spongiform neuropil was mainly occupied by swollen glial processes. The number of neuron and neuroglia were counted from photos under LM. The number of synaptic terminal was counted directly and the areal fraction of the constituents in the neuropil was measured stereologically in the EM photos. The number of neuron and neueroglia decreased significantly. Both the number of synaptic terminal in neuropil and the areal fraction of synaptic terminal decreased significantly. These changes were most prominent in the focus area of epileptic rats and in the parafocus area, too. This may indicate that the decrease of areal fraction of synaptic terminal results from the decrease of the number of synaptic terminal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid on the neuromuscular transmission of toad].

The effects of 2-chloro-4-bromo-alpha-methylcinnamic acid sodium (SC1001 Na) on neuromuscular transmission were tested by means of intracellular recordings in isolated sciatic nerve-sartorius preparations of toad. The results were: (1) at a concentration of 0.1mmol/L, SC1001 Na had no effect on end-plate potential (EPP); at a concentration of 1 mmol/L, SC1001 Na reduced the amplitude of the EPP significantly, and the paired-pulse facilitation was also decreased; at a concentration of 10mmol/L, SC1001 Na blocked the EPP completely; (2) the 0.1 mmol/L and 1mmol/L groups of drug had no effect on the resting potential of the toad muscle fibers; the resting potential was reduced significantly by SC1001Na at the concentration of 10mmol/L, the action of 10mmol/L drug was irreversible. These results suggest that SC1001 Na may block the neuromuscular transmission of toad, and the blocking effect might be mainly due to a presynaptic mechanism.

Animals↗
PubMed1995

Visual rehabilitation in low vision patients with aging macular degeneration.

Using optical visual aids, visual rehabilitation was performed in 14 cases (25 eyes) for low-vision patients with aging macular degeneration (AMD). With distance aids, visual acuity improvements were recorded for 24 eyes (95 percent) out of 25 eyes. Twelve eyes (48 percent) achieved vision equal to or better than 0.4. Utilizing near visual aids, the near visual acuity for all eyes (100 percent) were improved. Thirteen eyes (52 percent) received near vision equal to or better than 0.5. Ten patients were able to read No. 5 equal to or better than 0.5. Ten patients were able to read No. 5 Chinese print (corresponding visual angle is 0.67 at 30 cm of reading distance). The reading success rate was 71.4 percent. The results suggest that the application of visual aids is an effective method to improve the distance and near visual acuity of low vision patients with AMD.

Aged↗
PubMed1995

Purified murine long-term in vivo hematopoietic repopulating cells are not prothymocytes.

Analysis of kinetics of thymic repopulation by Rh123low, Lin-, Ly6A/E+, c-kit+ (Rh123low) cells, highly enriched for long-term in vivo hematopoietic repopulating cells, reveals that this population is deficient in thymic repopulation at week 3 after intravenous transplantation when compared to normal bone marrow cells. This suggests that the marrow prothymocytes have been depleted from this population, and analysis of thymic repopulation at week 3 can therefore be used to differentiate prothymocytes and their precursors. Using this short-term assay, the Rh123high, Lin-, Ly6A/E+, c-kit+ (Rh123high) population has been found to be relatively more efficient at early thymic repopulation, suggesting that this population contains the prothymocytes. In addition, the differentiation potential and reconstitution behavior of the Rh123high population observed after intravenous and intrathymic transfer strongly indicates that this population is at the transitional stage between the marrow primitive pluripotential and thymic more mature lymphoid restricted stem cells. We propose that the thymic repopulating ability of the Rh123low population is through generation of the more mature Rh123high progeny, presumably in the marrow.

Animals↗
PubMed1995

Modified vitreous surgery for subretinal neovascularization and hemorrhage.

PURPOSE: To modify vitreous surgery for subretinal neovascularization (SRNV) and to determine the effects of this operation. METHODS: Six patients with SRNV were performed with this operation. The methods of examination before and after operation included: testing the best-corrected visual acuity before operation and 1, 3 or 6 months after operation; 30 degrees and macular 10 degrees Humphrey visual field examination; FFA examination preoperatively and 1, 3 or 6 months postoperatively. Modified surgery procedure is: a preventive buckling; pars plana vitrectomy; peeling the vitreous cortical; no intraocular diathermy; small retinotomy; subretinal surgery; air-fluid exchange. RESULTS: SRNV was taken off in 4 cases. Subretinal hemorrhage was washed in 2 cases. After 4 to 7 months follow-up, the visual acuity was improved in 4 cases, unchanged in 2 cases. The visual field was improved in 4 cases, unchanged in 1 case, decraesed in 1 case. The complications included macular hole due to surgery in 1 case and subretinal hemorrage in 1 case. CONCLUSION: The surgery criteria were: 1) massive subretinal hemorrhage; 2) some patients of SRNV included: FFA evidence they showed the membrane is beneath fovea, the best V. A is 20/100 or lower, and can't be treated by laser and the patient consent. This modified subretinal operation is safe, and effective for massive hemorrhage and some SRNVS.

Adult↗
PubMed1995

[A potentially new sodium channel blocker: 2-chloro-4-bromo-alpha-methylcinnamic acid].

The effects of 2-Chloro-4-Bromo-alpha-Methylcinnamic acid sodium (SC1001 Na) and some channel antagonists on the action potential (AP) and the resting potential (RP) were tested intracellularly in the sartorius muscle of the toad (Bufo bufo gargarizans). TEA (10mmol/L) and MnCl2 (10 mmol/L) had no effect on the amplitude of the AP, otherwise, TTX (1 mumol/L) blocked the AP completely. SC1001 Na at the concentration of 2mmol/L largely decreased the amplitude of the AP and expanded the duration of the AP (measured at 1/2 peak amplitude), but it had no effect on the RP. The effects of ms group of drug were reversible. Under the pretreatment of the muscle preparation with TEA (10 mmol/L), SC1001 Na still increased the duration of the AP while decreased its amplitude. At the concentration of 10mmol/L, SC1001 Na completely blocked AP and depolarized the RP significantly. These effects were not reversible. As the structure of SC1001 Na is different from that of heterocycloguanidine Na channel blocker, such as TTX, or that of local anesthetics, we infer that SC1001 Na may be a new sodium channel blocker.

Action Potentials↗
PubMed1995

[Technological studies of effects of inclusion on pericarpium Citri reticulatae volatile oil-beta-cyclodextrin].

The effects of inclusion on Pericarpium Citri Reticulatae volatile oil-beta-cyclodextrin were studied by comparing four methods saturation, grinding, liquid to liquid and liquid to gas. The utilization ratio of oil, the ratio of oil in inclusion complex and the recovery of inclusion complex were used as the criteria in evaluating the inclusion effectiveness. The results showed that the saturation method was the best.

Citrus↗
PubMed1995

[Cultured human retinal pigment epithelial cell produced and secreted epidermal growth factor: its bioactivity and clinical significance].

The epidermal growth factor bioactivity from cultured primary human and monkey retinal pigment epithelial (RPE) cell systems was detected by using the radioreceptor assay. We report that the cultured human and monkey RPE cells produce and secrete the EGF bioactively to the media as demonstrated by radioreceptor binding assay. The EGF bioactivities secreted by human and monkey RPE cells were at peak of 48 hours (human RPE cells secreted 2.11 +/- 0.46 ng/ml vs monkey RPE was 1.56 +/- 0.12 ng/ml) in the serum-free media. The results indicate that the RPE is one of important sources for EGF in the eye. The RPE cells may play much important roles in the development of proliferative retinal diseases through the autocrine or paracrine mechanism. This new discovery will be helpful to elucidate the pathogenesis of proliferative retinal diseases and also provide an important basis for the treatment of such diseases.

Animals↗
PubMed1995

[Mitochondrial DNA polymorphism in the Han, Miao, Buyi, and Shui ethnic groups from Guizhou province].

Sixteen restriction endonucleases were used to assay the mtDNA polymorphism in the Han, Miao, Buyi and Shui ethnic groups from Guizhou province. Thirty-one restriction patterns were observed in a total of 150 subjects studied, out of which HacII-13, EcoRV-3 and PstI-4 are first reported by this paper. From all restriction patterns disclosed by 16 enzymes, twenty-eight mtDNA types were obtained. UPG method and parsimony networks were employed to analyze the clustering relationships between types or populations. Following conclusions are obtained: the mt-DNA from the Shui nationality possesses the highest polymorphism; the Han and the Miao are most closely related; and the genetic relation between the Buyi and the Shui is somewhat distant.

China↗
PubMed1995

A diagnostic practice study using international classification of epilepsies and epileptic syndromes in 302 cases.

We attempted to classify, according to the International Classification of Epilepsies and Epileptic Syndromes (1989), 302 patients at a tertiary epilepsy referral center. Proportion in categories as defined by the International League Against Epilepsy (ILAE) were as follows: localization-related epilepsies: 62.9%, generalized epilepsies: 22.2%, epilepsies undetermined whether focal or generalized: 14.2%, special syndromes: 0.7%. Only 26.8% cases were definitely classified in single diagnostic ILAE categories based on ictal CCTV/EEG recordings. The distribution of epileptic syndromes was different from the previous reports due to various methods of case ascertainment and inclusion criteria. Use of specific criteria for the reliability study of international classification has been proposed.

Adolescent↗