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Biomedical subjects

W Y Li

Publications and source records attributed to W Y Li.

At least 73 records · Page 4Linked to original sources
PubMed1990

CT evaluation of polymorphic reticulosis.

For the understanding of the CT findings of polymorphic reticulosis involving the upper respiratory tract, we reviewed eleven cases of this disease with initial CT study before treatment. CT revealed masses or swelling in the nose or nasal chamber, often with involvement of paranasal sinuses and medial parts of the orbit. In some, nonspecific minimal bony change (either bone destruction or bone sclerosis) was found. These CT findings are not specific. Any large mass in the nose and nasal fossa with little associated bone destruction should, however, raise the differential diagnosis of polymorphic reticulosis.

Adolescent↗
PubMed1990

Oral leiomyoma: case report.

Leiomyoma of the oral cavity is infrequently found because of the scarcity of smooth muscle in the mouth. A review of the literature yielded only 124 cases reported from 1884 to 1987. A new case of primary leiomyoma of the lower buccal sulcus is presented. Although the recurrence rate has been very low, wide surgical excision is recommended because of the high incidence of malignancy of this tumor in the oral cavity contrasted with other parts of the body.

Adult↗
PubMed1990

Intramural pericyte degeneration in early diabetic retinopathy study in vitro.

An experimental model of diseased pericytes was established by using cultured bovine retinal capillary pericytes in high--glucose medium. The high glucose stimulated polyol pathway, reduced cellular myo-inositol content and disturbed inositol phospholipid metabolism which resulted in a decrease in inositol trisphosphate (IP3) level. The correlation of suppressed IP3 levels with reduced DNA synthesis was evident. These findings suggested the biochemical mechanism by which retinal pericytes degenerate in high glucose. To supplement myo--inositol and/or an aldose reductase inhibitor to the high--glucose medium largely reversed the suppressed IP3 level and the decreased DNA synthesis. Therefore, these two manipulations may be considered as in vitro therapy to treat sick pericytes induced by high glucose.

Animals↗
PubMed1990

Metastatic malignant melanoma of upper gastrointestinal tract.

A 74-year-old male patient developed intermittent melena and anemia after he had received surgical resection for malignant melanoma of the right foot and radical dissection of the right inguinal metastatic lymph node. The source of bleeding was identified to be metastatic melanoma of stomach and duodenum by panendoscopy and biopsy. Patient refused surgical intervention and died of pneumonia two weeks later.

Aged↗
PubMed1990

Squamous cell carcinoma of the lip.

We reviewed 39 cases of squamous cell carcinoma of lip from 53 consecutive patients with carcinoma of the lip. The retrospective review includes age, location, risk factors, TNM classification, histologic differentiation, treatment methods, recurrent disease, site of recurrence, and follow-up status. Results reveal prognosis is related to original tumor size, local recurrence, and presence of cervical metastasis. Aggressive surgical treatment is recommended for identifiable poor prognostic lesions and includes surgical excision, prophylactic suprahyoid neck dissection, and possible radical neck dissection.

Adult↗
PubMed1989

Attenuation of phosphoinositidase activity and phosphatidylinositol bisphosphate level of bovine retinal capillary pericytes in high glucose.

Both phosphoinositidase (PIase) and individual species of inositol phospholipid (IPL) of bovine retinal capillary pericytes (BRCP) were quantitatively determined. When glucose in growth medium was increased from 5- to 15- or 30 mM, PIase activity was attenuated to 82% or 55%, respectively. In contrast, when glucose (5-, 15-, 30 mM) was added to an enzyme extract from cells grown in the standard growth medium (5 mM glucose, 0.04 mM myo-inositol) the PIase activity was not changed, indicating that the reduced PIase activity was not due to the direct effect of glucose. When IPLs from BRCP were analysed by HPLC and TLC, we observed reduction of the total and newly formed IPLs including the substrate of PIase. Phosphatidylinositol bisphosphate (PIP2). Reduced levels of IPLs were associated with a decrease in myo-inositol and an increase in sorbitol. The changes in IPL metabolism were reversed by adding either free myo-inositol or AL1576, an aldose reductase inhibitor (ARI), to the high-glucose medium. However, the addition of myo-inositol to the growth medium with a standard concentration of glucose only caused a marked increase in phosphatidylinositol, but not in PIP or PIP2, while the supplement of AL1576 in the standard medium did not cause any changes in IPL formation. These findings suggest that the alteration in IPL metabolism in BRCP may be related to insufficient myo-inositol or activated sorbitol pathway under high-glucose conditions. Further explanation of the role of the altered hydrolysis of PIP2 triggered by PIase may provide clues to understanding of the mechanism of decreased pericyte viability in the presence of high glucose concentrations.

1-Phosphatidylinositol 4-Kinase↗
PubMed1989

DNA-synthesis regulation and correlation with inositol trisphosphate levels in cultured bovine retinal capillary pericytes.

Inositol phosphate (IP), inositol bisphosphate (IP2) and inositol trisphosphate (IP3) in cultured bovine retinal capillary pericytes (BRCP) were quantitated by an ion-pair reverse-phase HPLC. BRCP were grown in media with standard (5 mM) or high (30 mM) glucose, and were either labeled with myo-[2-3H]inositol (20 microCi ml-1) for 60 hr or with dual isotopes (20 microCi ml-1 myo-[2-3H]inositol and 2 microCi ml-1 [14C]glycerol) for 8 hr. In parallel, BRCP in different glucose-media were incubated with 1 microCi ml-1 [3H]thymidine for 4 hr. High glucose significantly suppressed the accumulation of [3H]label in IP, IP2 and IP3, and specifically reduced the incorporation of [14C]glycerol into inositol phospholipids, but not that of neutral lipids and other types of phospholipids. The reduced IP3 level correlated with the decrease in the incorporation of [3H]thymidine into DNA. Both the reduced IP3 formation and DNA synthesis which were induced by high glucose were significantly reversed by adding either myo-inositol or AL1576, an aldose reductase inhibitor (ARI). However, the addition of neither myo-inositol nor ARI stimulated IP3 formation and/or DNA synthesis when BRCP were grown in the standard medium (5 mM glucose). These findings indicate that myo-inositol metabolism and the polyol pathway affect inositol phospholipid-mediated pericyte division in vitro only under the high-glucose condition. These data are compatible with the hypothesis that altered inositol phospholipid metabolism accounts for the loss of pericytes in diabetic retinopathy.

Animals↗
PubMed1989

Activation of Mg-ATPase of skeletal-muscle myosin by bovine retinal pigment epithelial actin.

The morphology and function of actin in cultured bovine retinal pigment epithelial (RPE) cells were studied. Filamentous actin was identified with a fluorescent mushroom toxin, nitrobenzoxadiazole (NBD)-phallacidin, specific for actin. Dark-field microscopy of cultured RPE cells revealed numerous pigment granules; fluorescent microscopy identified scattered lipofuscin granules. One-dimensional SDS polyacrylamide gel electrophoresis of urea-soluble proteins extracted from RPE cells showed a 46,000-dalton protein band which comigrated with authentic muscle actin. Densitometric scanning showed that this protein band comprised 7.6% of the total urea-soluble proteins. An actin-activated skeletal-muscle myosin Mg-ATPase assay, using skeletal-muscle heavy meromyosin as enzyme and [gamma-32P]-ATP as substrate, demonstrated functional actin in RPE cell extracts after DEAE-cellulose anion exchange chromatography. The actin-containing protein fractions were eluted at ionic strengths between 0.19 and 0.36 M KCl. The activation of myosin ATPase by actin in RPE cells provides a molecular basis for the phagocytic activity which is important in maintaining the integrity of retinal photoreceptor cells.

Actins↗
PubMed1989

[DNaseI sensitivity and DNaseI hypersensitive sites of AFP gene correlated with the gene expression].

Using rat AFP cDNA clone pRAF87 and subcloned 5' end fragment of AFP gene as probes, we have analysed the DNaseI sensitivity and DNaseI hypersensitive sites of AFP gene in chromatin of rat fetal liver (active transcription), adult liver (potentially active transcription) and adult kidney (inactive transcription). The results indicated that fetal liver AFP genes are much more sensitive than their counter parts. There are three DNaseI hypersensitive sites in the fetal AFP gene, namely, upstream -3kb region, 1.37kb region just around transcription start sites and the last located in downstream 4.1 kb EcoR I fragment. The 1.37 kb DNasI hypersensitive site also exists in adult liver. The relationship between AFP gene DNaseI sensitivity, DNaseI hypersensitive sites and AFP gene expression have been discussed.

Animals↗
PubMed1989

Acute cerebrovascular disorder induced by allergic vasculitis. A case report.

A patient with vascular disease of the brain due to allergic vasculitis, which had been misdiagnosed for many years, was given anti-inflammatory, antituberculosis and antitumor drugs with no avail. He was admitted this time for an attack after eating food prepared with leftover oil used for frying hairtail. Considering the possibility of allergic vasculitis, we tried antianaphylactics and immunosuppression drugs including dexamethasone with satisfactory results. The final diagnosis was allergic granulomatous vasculitis.

Cerebrovascular Disorders↗
PubMed1989

[Abnormal inositol phospholipid metabolism as a main factor causing pericyte drop-out in diabetic retinopathy].

The biochemical basis of pericyte loss in early diabetic retinopathy is still an open question. In studies on the mechanism by which retinal pericytes degenerate, we first established a bovine retinal capillary pericyte (BRCP) cell line. Subcultured BRCP grown in high (10-40 mmol/L) glucose media were used as an experimental model. We found that high concentrations of glucose suppress the mitotic rate and cell birth rate of cultured BRCP. High concentrations of glucose inhibit myo-inositol transport and result in decreased intracellular myo-inositol content. This inhibition can be partially reversed by sorbinil, an aldose reductase inhibitor (ARI). Myo-inositol is a precursor of inositol phospholipids (IPLs), whose metabolism is responsible for a number of signal transduction processes. Phosphoinositidase (PIase) cleaves the phosphodiester bond of phosphotidylinositol 4,5 diphosphate (PIP2) to produce two second messengers, inositol trisphosphate (IP3) and diacylglycerol (DG). Further experiments showed that IP3 and DG synergistically activate BRCP proliferation in vitro. High concentrations of glucose altered the formation of both IPLs and inositol phosphate esters (IPEs) in an organ culture of retinal microvessels. This alteration can be reversed by adding either high concentrations of myo-inositol or ARI to the medium. PIase activity was attenuated to 82% or 55% when glucose in the growth medium was increased from 5 to 15 or 30 mmol/L, respectively. When IPLs from BRCP were analyzed by HPLC and TLC, we observed the reduction of three IPLs, including the substrate of PIase, PIP2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Reductase↗
PubMed1989

[The biochemical mechanism in vitro of pericyte drop-out in diabetic retinopathy].

An experimental pathologic model of pericyte drop-out was established with capillary pericytes in culture medium of high glucose concentration. The high glucose activated the sorbitol pathway, reduced the intracellular myo-inositol content and disturbed the inositol phospholipid metabolism which resulted in a decrease in the inositol trisphosphate (IP3) level. The correlation of suppressed IP3 level with reduced DNA synthesis was evident, suggesting the mechanism that retinal pericytes degenerated in high glucose concentration. In vitro test of adding myo-inositol and/or aldose reductase inhibitor to the high-glucose medium reversed the inositol phospholipid metabolism and the decreased DNA synthesis, which could hold promise for the clinical prevention and treatment of early diabetic retinopathy.

Animals↗
PubMed1989

[Effect of expression of exogenous PDGF-A chain on growth and transformation of CHO cells].

CHO cells were transfected with plasmid pSV2-PDGF-A (containing human PDGF-A cDNA) by calcium phosphate method. Twenty transfected cell lines were obtained after G418 selection. The selected 2 cell lines At1 and Aot7), with prominent changes in morphology and growth behaviour, showed transcription of PDGF-A chain mRNA much higher than CHO cells, strong fluorescent PDGF-specific reaction, appearing that PDGF-like proteins were synthesized in cytoplasm of these cells. At1 and Aot7 cells not only had increased growth rate, but also formed large colonies in soft agar and grew into fibrosarcomas in nude mice. These results suggested that the expression of exogenous PDGF-A gene might cause the uncontrolled growth and malignant transformation of CHO cells.

Animals↗
PubMed1989

[Expression of exogenous platelet-derived growth factor B chain gene in CHO cells].

CHO cells were transfected with plasmid pSM-1 (containing human c-sis cDNA) singly or co-transfected with pSV 2 neo DNA by calcium phosphate method. After low serum or G418 selection several cell lines with expression of platelet-derived growth factor (PDGF) were obtained. One among them, FB5, was of the highest PDGF expression and showed the following biological characteristics when compared with CHO cells: (1) a prominent change in morphology from spindle to round in shape: (2) increase of growth rate; (3) growth in low serum (2%) medium as a semisuspension culture; (4) growth on soft agar to larger colonies; (5) synthesis of PDGF in cytoplasm identified by immunofluorescent method; (6) the conditioned medium stimulated DNA synthesis of NRK cells; (7) RNA dot hybridization showing high transcription of PDGF mRNA; (8) southern blot showing integration of human c-sis gene was still stable after 7 months. These results indicated that intergration of exogenous c-sis gene and its high expression might cause CHO cells to high growth rate and even transformation. The establishment of this stable transformed cell line, FB5 is thought to be a good model for further study on the function of PDGF in cell growth control and cell transformation.

Animals↗
PubMed1988

Prostacyclin is the major prostaglandin synthesized by bovine retinal capillary pericytes in culture.

Prostaglandin synthesis by bovine retinal pericytes was investigated using high pressure liquid chromatography to separate and identify 3H-labeled prostaglandins released from 3H-arachidonic acid labeled pericyte monolayers. A dominant peak activity corresponding to 6-keto-PGF1 alpha was observed. This peak was eliminated when monolayers were pretreated with cyclooxygenase inhibitors and was augmented when monolayers were stimulated by the calcium ionophore A23187. Suspensions of pericytes and the cell-free media of monolayers incubated with arachidonic acid inhibited adenosine diphosphate-, collagen-, and arachidonic acid-stimulated platelet aggregation in a bioassay for prostacyclin-like activity. This inhibitory activity was unstable at room temperature. Cultures of 7.5 to 10 x 10(5) pericytes (7th passage near-confluence) released nanogram quantities of 6-keto-PGF1 alpha as measured by radioimmunoassay. These results are evidence that prostacyclin is the main prostaglandin synthesized by bovine retinal capillary pericytes in culture. Pericytes may influence the microcirculation via their production and release of this potent vasoactive arachidonic acid metabolite.

Animals↗