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Biomedical subjects

Y Jiang

Publications and source records attributed to Y Jiang.

At least 469 records · Page 26Linked to original sources
PubMed1997

[Determination of glutamine in intestinal mucosa by pre-column derivatization/reversed-phase high performance liquid chromatography with fluorescence detection].

A high performance liquid chromatographic pre-column derivatization method with fluorescence detection for the analysis of glutamine (Gln) in rat intestinal mucosa is presented. Gln was derivatized with o-phthalaldehyde and 3-mercaptopropionic acid under an alkaline condition and separated by reversed-phase liquid chromatography on a Lichrosorb RP18 column (150 mm x 4.6 mm i.d., 5 microm). The mobile phase was consisted of 50 mmol/L phosphate buffer (pH 7.0)-acetonitrile (94:6, V/V) with a flow rate of 2.0 mL/min. The excited and emitted wavelength were selected at 230 nm and 389 nm respectively. The volume ratio of samples and derivatization reagent solution was 4:1 (V/V). The detection limit of Gln was 25 micromol/L (S/N= 3.5) and the regression equation was A = 16.9405C + 179.9339, r = 0.9996 at the linear range of 50-3200 micromol/L. The day-to-day deviation was 6.97% (n = 3) and the retention time of Gln was 3.158 min. This method is rapid, simple and highly sensitive, and has been applied to the determination of Gln in intestinal mucosa.

Animals↗
PubMed1997

Glucosylceramide metabolism is regulated during normal and hormonally stimulated epidermal barrier development in the rat.

Glucosylceramides, delivered to the stratum corneum interstices by exocytosis of lamellar body contents, are enzymatically hydrolyzed to ceramides, which are major components of the lipid lamellar bilayers that mediate epidermal barrier function. Because this conversion is critical for permeability barrier homeostasis in the adult animal, in this study we measured the changes in activities of the enzymes responsible for the synthesis of glucosylceramide and its conversion to ceramide, UDP-glucose:ceramide glucosyltransferase (GC synthase) and beta-glucocerebrosidase (beta-GlcCer'ase), respectively, during fetal barrier formation. In epidermis from rats of gestational age 17-21 days, GC synthase activity peaked on day 19, prior to barrier competence, whereas beta-GlcCer'ase activity rose throughout barrier formation, exhibiting a 5-fold increase over this time period. beta-GlcCer'ase protein rose in parallel with activity, as did mRNA levels. Enzyme activities in skin explants from 17-day fetal rats, incubated up to 4 days in hormone- and serum-free media, paralleled those measured at corresponding time points in utero. Incubation with hormones that accelerate barrier development had minimal effects on GC synthase activity, whereas beta-GlcCer'ase activity was significantly increased after 1 or 2 days in culture. Finally, inhibition of beta-GlcCer'ase with conduritol B epoxide prevented barrier development in vitro and was accompanied by abnormalities in the lamellar bilayer ultrastructure of the stratum corneum. These data indicate that both synthesis and hydrolysis of glucosylceramide are regulated during fetal development. Furthermore, the enzymatic hydrolysis of glucosylceramide to ceramide is essential for fetal barrier ontogenesis.

Animals↗
PubMed1997

Quantitative analysis of light sensitivities in central 30-degree visual field of normal Chinese and glaucoma patients.

OBJECTIVE: To examine the difference in the light sensitivity in the central visual field between the normal subjects and patients with or without the early visual field damages and propose the criteria to identify the possible early disturbances in the visual field. METHODS: Light sensitivities at the 76 locations in the central field were measured in 108 normal eyes of 75 normal volunteers aged from 20 to 78 years, and 82 eyes of 53 patients with early open-angle or closure-angle glaucoma on the Humphrey Field Analyzer (Model 610), using the Central-30-2 program. RESULTS: No sex and eye differences were found. The significant differences in the light sensitivities existed between the age of 20-45 years and the age of 46-78 years in the normal subjects. The lower limit of 80% normal range for each location in the central field of the two age groups was calculated. The light sensitivity decreased by 2-3 dB at every 10 degree from the eccentricity. The light sensitivity in the inferior field was 1-2 dB higher than that in the superior field. There was no statistical difference between the nasal and the temporal field. For the patients with the field defects, the light sensitivity of many locations decreased by 4-8 dB, and by 1-2 dB in the patients without the field defects as compared with the normal controls. CONCLUSIONS: Based on comparisons with the normal controls and the lower limit of 80% normal range, we proposed the following criteria for classification of the damages in the glaucoma visual field. Grade I: light sensitivity reduces by 1-3 dB at a cluster of locations in the field; Grade II: light sensitivity reduces by 4-6 dB at a cluster of locations in the field; Grade II: light sensitivity reduces by more than 6 dB at a cluster of locations in the field.

Adult↗
PubMed1997

Clinical significance of the immunohistochemical detection of p53 protein in endoscopic biopsy specimens.

OBJECTIVE: To evaluate the utility of immunohistochemical staining of p53 expression in endoscopic biopsy specimens in clinical practice. METHODS: Using a streptavidin-peroxidase (S-P) conjugate method with monoclonal p53 antibody Do-7, the expression of p53 was investigated immunohistochemically in 150 endoscopic biopsies and paired brushings from patients with benign and malignant gastric diseases. Among them, 22 cases with gastric carcinoma underwent the gastrectomy and the immunohistochemistry was repeated in the resected cancerous tissues of the same patient. RESULTS: p53 expression in endoscopic specimens was detectable in 35.7% cases of gastric carcinoma (n = 70), 5.9% of gastric polyps (n = 17), 16.7% of gastric mucosal dysplasia (n = 18) and 4.0% of chronic atrophic gastritis (n = 25), but no protein expression was observed in cases of chronic active gastritis (n = 20). In 22 patients with tumor resection, 8 (36.4%) were identified with p53 expression in endoscopic specimens before surgery, while 10 (45.5%) were identified with the same expression in surgical specimens, the real positive rate was 80.0%, no false positives were observed in endoscopic specimens. Furthermore, p53 expression in gastric carcinoma was closely correlated with clinical stage and lymph nodes involvement, but did not correlate with histologic type. CONCLUSIONS: Assay of p53 by immunohistochemistry in endoscopic biopsy specimens and brushings is an easy and reliable technique to assess p53 status in gastric carcinoma, and thus could serve as a marker to foresee the prognosis in these patients and assist in the diagnosis of malignancy before surgery. It may also be a valuable marker in screening patients with high risk of gastric carcinoma.

Adenocarcinoma↗
PubMed1997

[Molecular cloning and sequence analysis of glycoprotein D gene of herpes simplex virus 2 strain Sav and wild strain isolated].

OBJECTIVE: To study the difference of structure and function of HSV-2 gD gene among the wild strain, G and Sav strain. So as to provide theoretical basis for future production of HSV-2 vaccine. METHOD: The partial glycoprotein D gene sequence of HSV-2 strain Sav and wild strain isolated from recurred genital herpes simplex were amplified and cloned with PCR. RESULTS: The homology comparison showed that the homology of DNA and amino acid were 99.2% and 99.1% respectively. CONCLUSIONS: There are high homology of HSV-2 gD gene among the wild strain G and Sav strains, but some variations existed.

Amino Acid Sequence↗
PubMed1997

[The shrinkage of ovarian and uterine size and the decline of serum estradiol level in post-menopausal women].

OBJECTIVE: To investigate the shrinkage of ovarian and uterine size, and the decline of serum estradiol (E2) level in normal women. METHODS: Ovarian and uterine area of 92 perimenopausal and 292 postmenopausal women, measured by transvaginal ultrasonography, were analysed retrospectively and were compared with those of the controls consisting of 41 normal women in midfollicular phase, so did the serum E2 levels. RESULTS: As compared with the control group, ovarian area and endometrium thickness shrunk on an average of 30%, 2% and 56%, 48% in early perimenopausal and postmenopausal groups respectively. Serum E2 level and uterine area increased by 11% and 38% in early perimenopausal group, but decreased by 67% and 21% in postmenopausal groups respectively. No obviously further decline of serum E2 level was found 1 year after menopause, and of ovarian, uterine area 3-5 years after menopause. CONCLUSION: These data represent a normal profile of ovarian and uterine shrinkage and decline of serum E2 levels related to the time of menopause.

Adult↗
PubMed1997

Short-term clinical study on a new aqueous humor drainage implant for refractory glaucoma.

OBJECTIVE: To investigate the therapeutic effect of a new aqueous humor drainage (HAD) implant made in China for the treatment of refractory glaucoma. METHODS: The implant was designed by ourselves and manufactured by Beijing Rubber Products Design and Research Institute. From July, 1993 to September, 1995, we observed 40 patients (41 eyes) with refractory glaucoma treated by implantation surgery, including 16 eyes with neovascular glaucoma (NVG) and 25 eyes with non-neovascular glaucoma (NNVG). RESULTS: The mean period of postoperative follow-up was 9.2 (range, from 3-27) months, the intraocular pressure (IOP) was lowered from preoperative 7.20 +/- 1.51 kPa to postoperative 2.40 +/- 1.33 kPa in NVG group and from preoperative 6.27 +/- 1.07 kPa to postoperative 2.00 +/- 2.93 kPa in NNVG group. The success rate was 81% in NVG group and 84% in NNVG group. The common postoperative complications were flat anterior chamber, hyphema and choroidal detachment. CONCLUSIONS: Our newly designed aqueous humor drainage implant is an economical implant in China and one of the alternative and effective methods for the treatment of refractory glaucoma. It can be widely used in clinics.

Adult↗
PubMed1997

[Spectral analysis of R-R intervals in adolesent persons during mental stress].

In this study, power spectrum analysis of the autoregressive model was used to quantitatively estimate the power spectrum of R-R intervals in adolesent during the state of the mental stress. The power spectrum density of the lower frequency (HF: 0.05-0.15 Hz) and the high frequency (HF: 0.15-0.5 Hz) component were acquired. The results showed that during the mental stress the HF component decreased significantly (P < 0.001) while the LF component increased relatively and the center frequency of the HF increased remarkably (P < 0.001). This suggests that the spectral analysis of heart rate variability (R-R interval) offers an efficient non-invasive method to assess the autonomic nerve activity of cardiovascular system during the stress condition.

Adult↗
PubMed1997

[A study on cell malignant transformation caused by dihydroxyglyoxime].

BALB/c-3T3 cell transformation test was used to detect cell carcinogenicity caused by dihydroxyglyoxime (DHG) and determine its carcinogenicity in vitro. Results showed that DHG could induce transformation of BALB/c-3T3 cells and the transformed cells could agglutinate in the presence of Con A and grew in the soft agar. Transformed cells could induce the formation of fibrosarcoma if they were inoculated subcutaneously into the naked mice. It indicated sufficiently that the transformation in BALB/c-3T3 cell culture was malignant, and also predicted its potential carcinogenicity in human beings.

3T3 Cells↗
PubMed1997

[Factors analysis of pregnancy success in chronic glomerulus diseases].

Ten cases pregnant chronic glomerule diseases patients were treated. 4 cases complicated hypertension and renal failure were failed to maintain their pregnancy. 6 cases whose glomerule disease were active but not complicated with hypertension and/or renal failure had their pregnancy successed. The results suggest that three factors should be put attention for pregnancy success in cases with concomitant chronic glomerule diseases. 1) Accurate evaluation of the criteria to allow pregnancy for patients with chronic glomerule diseases. 2) Immunosuppressive therapy should be maintained during pregnancy. 3) Regular follow up to detect and treat the complications promptly during pregnancy is never over emphysized.

Adult↗
PubMed1997

[Mitomycin C concentrations in rabbit ocular tissues after topical administration during glaucoma filtration surgery].

Using high-performance liquid chromatography, we measured Mitomycin C (MMC) concentrations in conjunctiva, sclera and aqueous of 22 rabbit eyes after single topical administration of 0.2 mg.ml-1 MMC during glaucoma filtration surgery. The peaks of MMC concentrations in conjunctiva, sclera, aqueous were 2.01 micrograms.g-1, 2.95 micrograms.g-1 and 0.16 microgram.ml-1 with half life of 0.63, 0.35 and 0.84 hours respectively. Irrigating the ocular surface with 20 ml of normal saline after MMC application reduced the peak drug concentration to 1/8 in conjunctiva, to 1/5 in sclera and to 1/3 in aqueous. The results showed that the MMC concentrations in conjunctiva and sclera were well above the ID50 of rabbit subconjunctival fibroblast (0.1 microgram.ml-1), and the concentration in aqueous was well below the level known to cause endothelium toxicity (approximately 0.2 mg.ml-1) and retinal toxicity (> 1.3 micrograms.ml-1). Therefore, 0.2 mg.ml-1 MMC can inhibit subconjunctival fibroblast effectively and has no side effect on visual function.

Administration, Topical↗
PubMed1997

[A histopathological study on Hunan aqueous drainage implantation in rabbit's eye].

Thirty eyes with 15 healthy white New Zealand rabbits subgrouped into two groups: right eye as an experimental group which was implanted Hunan aqueous drainage (HAD) and left eye served as self-control group in which a silicone band 7 mm in width and 7 to 10 mm in length was placed equatorially around the globe. Within 1 to 12 weeks postoperatively, we examined the anterior segment of the globe by the slit lamp microscopy (SLM) and made histopathological observation under light microscope after sacrifice and enucleation of eyeballs in five batches. SLM examination showed that 8 out of 15 eyes in experimental group showed mild or moderate ocular reaction which subsided within 2 to 14 days postoperatively. Histopathological observation revealed no obvious pathological lesions in the uveal tract tissues in the most globes. No foreign body macrophages were found. It indicates that HAD implant is nontoxic and nonallergenic, so it is adaptable for rabbit ocular tissue. The HAD implant can be used in human eyes, too.

Animals↗
PubMed1997

[The clinical effect after locally using mitomycin C during trabeculectomy in glaucoma].

To improve the function of filtering blebs after trabeculectomy, we divided randomly 44 patients (60 eyes) with moderate or late glaucoma into mitomycin C and control groups (30 eyes per group). Two small surgical sponges were soaked with 0.2 mg.ml-1 mitomycin C solution. One sponge was put on the top of the superficial scleral flap, the other was placed underneath the scleral flap and contacted with the bed of the scleral flap. After 5 minutes the wound was then irrigated with normal saline. All patients were followed up from 1 to 12 months (7.9 +/- 4.0 months). We found that: (1) functional filtering blebs were 92.9% in the mitomycin C group and 55.2% in the control group (P < 0.01), (2) the decreasing percentage of intraocular pressure (IOP) in the mitomycin C group was much more than that in the control group (P < 0.05), (3) the successful rates of the operation in MMC group were higher than that of the control group, and the visual field was effectively maintained in MMC group.

Administration, Topical↗
PubMed1996

Regulation of phosphatidic acid phosphohydrolase by epidermal growth factor. Reduced association with the EGF receptor followed by increased association with protein kinase Cepsilon.

An important component of receptor-mediated intracellular signal transduction is the generation of lipid second messengers. Lipid second messenger production is a complex process involving a variety of regulatory enzymes that control the intracellular response to the extracellular signal. Phosphatidic acid (PA) is generated in response to phospholipase D and can be converted to other lipid second messengers including diacylglycerol (DG) and lysophosphatidic acid. PA is converted to DG by PA phosphohydrolase (PAP). We report here that PAP activity can be detected in epidermal growth factor (EGF) receptor immunoprecipitates. Following treatment with EGF, there is a substantial reduction in the PAP activity that co-precipitates with the EGF receptor. The loss of EGF receptor-associated PAP activity occurs with a concomitant increase in PAP activity associated with the epsilon isoform of protein kinase C (PKC). The PAP activity associated with PKCepsilon was dependent upon the PKC co-factors phosphatidylserine and DG but was independent of the kinase activity of PKCepsilon. These data suggest a novel signaling mechanism for the regulation of lipid second messenger production and implicate PAP as an important regulatory component for lipid second messenger production in receptor-mediated intracellular signaling.

Cell Line↗
PubMed1996

The primary structure of p38 gamma: a new member of p38 group of MAP kinases.

We have identified a third member of the p38 group of MAP kinase termed p38 gamma. The cDNA for this MAP kinase encodes an 367 amino acid polypeptide that is slightly greater than 60% identical to p38 and p38 beta. Expression of its mRNA is primarily in muscle with no detectable expression in Northern blots using RNA from other tissues. In contrast to p38 and p38 beta, p38 gamma, fails to phosphorylate ATF-2 or MAPKAP kinase 2 but does like other MAP kinases phosphorylate MBP. In vivo kinase assays using protein extracts from skeletal muscle reveal that a 7-kDa protein is phosphorylated by p38 gamma but not by other members of this group of kinases. We suggest p38 gamma may have unique functions when compared with other members of the p38 group due to its restricted tissue expression and apparent substrate preferences.

Amino Acid Sequence↗