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Biomedical subjects

Shan Lin

Publications and source records attributed to Shan Lin.

17 recordsLinked to original sources
PubMed2026

Screening, Physiological Characterization, Genomic Analysis and Optimization by Conjugated Linoleic Acid Bioconversion of Two Lactiplantibacillus plantarum Strains.

Conjugated linoleic acid (CLA) comprises a group of C18 fatty acids containing conjugated double bonds and has been associated with potential anti-obesity and antitumor effects. In this study, 116 presumptive lactic acid bacteria (LAB) isolates were recovered from homemade Sichuan pickles. Primary screening identified 28 CLA-producing isolates, among which strains 7# and 31# showed the highest absorbance at 233 nm (A233). CLA production by both strains was subsequently optimized and quantified using gas chromatography-quadrupole time-of-flight mass spectrometry (GC-Q-TOF). Under the optimized conditions, strain 31# produced 66.50 ± 3.80 μg/mL total CLA, including 52.70 ± 3.29 μg/mL c9,t11-CLA and 13.80 ± 0.51 μg/mL t10,c12-CLA. Strain 7# produced 26.79 ± 1.09 μg/mL total CLA, including 14.05 ± 0.49 μg/mL c9,t11-CLA and 12.74 ± 0.60 μg/mL t10,c12-CLA. Physiological, biochemical, and safety assessments showed that strain 31# outperformed strain 7# overall, supporting its use in further product development and mechanistic studies. Functional annotation using the COG database and pathway mapping with KEGG identified candidate genes encoding an enzyme associated with linoleic acid isomerization in both strains. Potential mechanisms underlying their different CLA-producing capacities were also examined, providing a basis for the selection and development of high-CLA-producing strains.

conjugated linoleic acid↗
PubMed2006

Enhanced vanillin production from ferulic acid using adsorbent resin.

High vanillin productivity was achieved in the batch biotransformation of ferulic acid by Streptomyces sp. strain V-1. Due to the toxicity of vanillin and the product inhibition, fed-batch biotransformation with high concentration of ferulic acid was unsuccessful. To solve this problem and improve the vanillin yield, a biotransformation strategy using adsorbent resin was investigated. Several macroporous adsorbent resins were chosen to adsorb vanillin in situ during the bioconversion. Resin DM11 was found to be the best, which adsorbed the most vanillin and the least ferulic acid. When 8% resin DM11 (wet w/v) was added to the biotransformation system, 45 g l(-1) ferulic acid could be added continually and 19.2 g l(-1) vanillin was obtained within 55 h, which was the highest vanillin yield by bioconversion until now. This yield was remarkable for exceeding the crystallization concentration of vanillin and therefore had far-reaching consequence in its downstream processing.

Adsorption↗
PubMed2006

Correlation between intraocular pressure, central corneal thickness, stage of glaucoma, and demographic patient data: prospective analysis of biophysical parameters in tertiary glaucoma practice populations.

PURPOSE: To determine the correlation of central corneal thickness (CCT) to Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT, PASCAL), and to glaucoma stage as assessed by cup-to-disc ratio (CDR). DESIGN: Prospective, cross-sectional tricenter observation study. PATIENTS AND METHODS: From three glaucoma specialty practices a sample of 406 independent eyes was included. After ultrasound pachymetry, intraocular pressure was measured using PASCAL and Goldmann applanation tonometry and cup-to-disc ration was reassessed. Demographic data were included in the multivariate analysis. RESULTS: Mean corneal thickness was 540 microm. African Americans and normal-tension glaucoma patients showed the lowest values (518 microm and 522 microm, respectively). These values were significantly thinner than the central corneal thickness of Caucasians (549 microm) and ocular hypertensives (564 microm). Intraocular pressure assessed by Goldmann applanation tonometry shows a significant correlation with central corneal thickness (r = 0.068, P < 0.001), whereas PASCAL is not significantly associated with central corneal thickness (r < 0.001, P = 0.997). Increased IOP is significantly correlated with large ocular pulse amplitudes (r = 0.13, P < 0.001), which is predominantly seen in ocular hypertensives. A significant negative correlation was detected between cup-to-disc ratio and central corneal thickness (r = 0.102, P < 0.001). CONCLUSION: Glaucoma patients with thin central corneal thickness are more likely to be found at an advanced stage of the disease and among those with normal-tension glaucoma and black African ancestry. Underestimation of intraocular pressure by Goldmann applanation tonometry could be one causative factor.

Adolescent↗
PubMed2006

Studies on characteristics of nanostructure of N-TiO2 thin films and photo-bactericidal action.

Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis strain (AS1.439) from Ming lake were decomposed by photocatalytic nanostructure N-TiO(2) thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO(2) thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 degrees C (films A) or 350 degrees C (films B) for 1 h in a muffle furnace. The results showed that N-TiO(2) thin film B (8.18 nm thickness, 2.760 nm height and 25.15 nm diameter) has more uniform granular nanostructure and thinner flat texture than N-TiO(2) thin film A (12.17 nm thickness, 3.578 nm height and 27.50 nm diameter). The bactericidal action of N-TiO(2) thin film A and film B for Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis varniger strain (AS1.439) were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain (AS1.50) and 75% for Bacillus subtilis strain (AS1.439) were achieved by using N-TiO(2) thin films-B for 70-80 min of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO(2) thin films probably depended on the characteristics of the films.

Anti-Bacterial Agents↗
PubMed2005

Clinical comparison of contour and applanation tonometry and their relationship to pachymetry.

OBJECTIVES: To compare intraocular pressure readings of recently introduced dynamic contour tonometry (DCT) with pneumatonometry (PTG) and Goldmann applanation tonometry (GAT) and to correlate central corneal thickness (CCT) with these readings. DESIGN: Prospective, cross-sectional observation and instrument validation study. We included 258 independent eyes with normal anterior segment examinations results, irrespective of glaucoma diagnosis or glaucoma suspect. After pachymetry, DCT, PTG, and GAT were performed in a randomized order. Intraocular pressures as measured by DCT, PTG, and GAT were compared with each other and with CCT. RESULTS: Eyes with thinner CCTs tended to yield lower intraocular pressure measurements by GAT. A significant correlation (Pearson product moment correlation, P<.001) between CCT and GAT was found with a regression of 0.25 mm Hg per 10 microm (R2 = 0.060). Variation of CCT had no significant effect on intraocular pressure measurements by PTG (P = .10; R2 = 0.01) and DCT (P = .80; R2<0.01). A piecewise regression model showed that GAT readings are not linearly correlated with CCT. Comparison of the slopes below and above 535 microm showed the highest significance (P<.001). CONCLUSIONS: Goldmann applanation tonometry readings are potentially influenced by CCT, whereas PTG and DCT seem to be less dependent on CCT. Correlation between CCT and GAT is not linear. A simple correction formula suggesting a linear relationship might not be correct.

Adolescent↗
PubMed2004

Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans, and Japanese in a glaucoma clinic.

OBJECTIVE: To characterize the central corneal thickness (CCT) of Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American patients in a multiethnic glaucoma practice. DESIGN: Retrospective study (chart review). PARTICIPANTS: Glaucomatous (n = 600) and nonglaucomatous (n = 201) eyes of 801 patients examined in a San Francisco glaucoma clinic from June 2002 to April 2004 who met inclusion criteria were included in the study. The 6 racial (ethnic) groups represented in the study were Caucasian (n = 186, 23.2%), Chinese (n = 157, 19.6%), Japanese (n = 121, 15.1%), Hispanic (n = 116, 14.5%), Filipino (n = 114, 14.2%), and African American (n = 107, 13.4%). METHODS: Central corneal thickness was measured by means of ultrasound pachymetry in Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American participants with glaucomatous and normal eyes. The relationship between CCT and race was investigated using multivariate regression analyses, controlling for confounders. One eye of each of 801 participants was included for analysis. MAIN OUTCOME MEASURES: Correlation of mean CCT with race, glaucoma diagnosis, age, spherical equivalent, gender, and history of ocular surgery. RESULTS: The mean CCT of all participants was 542.9 mum. Central corneal thicknesses of Chinese (555.6 microm), Caucasian (550.4 microm), Filipino (550.6 microm), and Hispanic (548.1 microm) participants did not significantly differ. The CCT of Japanese participants (531.7 microm) was significantly less than that of Caucasians, Chinese, Filipinos, and Hispanics (all, P< or =0.001) and greater than that of African Americans (P = 0.03). African Americans had a CCT (521.0.0 microm) less than that of all races (P< or =0.05). Glaucoma suspects and patients with normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and chronic angle-closure glaucoma (CACG) had corneas significantly thinner than those of normal participants (P< or =0.004), whereas ocular hypertensives had significantly thicker corneas (P<0.0001). Among all participants, decreasing values of CCT were significantly related to older age (P<0.01). Less negative or more positive refractive errors, gender, and history of ocular surgery were not associated with changes in CCT (P = 0.38, P = 0.50, and P = 0.97, respectively). CONCLUSIONS: Studies examining individual Asian subpopulations in isolation suggest that differences in CCT may exist among different Asian groups. The results of this study indicate that CCT does, in fact, vary among Asian subpopulations; Japanese have thinner corneas than Chinese and Filipinos. Caucasians, Chinese, Hispanics, and Filipinos have comparable CCT measurements, whereas the corneas of African Americans are significantly thinner. Additionally, older individuals; glaucoma suspects; and participants with NTG, POAG, PEX, and CACG have thinner corneas. Ocular hypertensives, however, have thicker corneas.

Adult↗
PubMed2003

[Alteration of P53 protein expression and p53 gene in laryngeal carcinoma].

OBJECTIVE: To study the prevalence of P53 protein expression and p53 gene mutation in laryngeal carcinoma. METHODS: Using immunohistochemistry P53 expression was detected in 31 patients with laryngeal carcinoma. In 11 P53 negative patients,microdissection-PCR-HA technique was used to determine mutation in p53 exon 5, 6, 7, 8. RESULTS: Among the 31 patients tested with immunostaining, the overall average positive rate was 64.5%. Positive rates for T3 and T4 tumors were 86.7% vs 43.8% in T1 and T2 tumors.The positive rate was 91.7% in those with cervical node metastasis compared with 47.4% in those without lymph node metastasis. The positive P53 immunostaining was more frequently found in poor differentiated carcinoma (87.5%) and moderate-differentiated carcinoma (66.7%),than in well differentiated carcinoma (45.5%). The abnormal exon 5 or 7 of p53 gene were detected in 2 out of 11 cases, in which P53 was negative. CONCLUSION: P53 gene mutation is related with TNM grading and cervical lymph node metastasis in laryngeal carcinoma. P53 mutation tents to be correlated to pathologic grading.

Adult↗
PubMed2003

[Study on the relationship between angiogenesis and cervical lymphatic metastasis in head and neck squamous cell carcinomas].

OBJECTIVE: To investigate the relationship between tumor angiogenesis and cervical lymphatic metastasis and the expression of vascular endothelial growth factor in head and neck squamous cell carcinomas. METHOD: Fifty-eight head and neck carcinoma tissue slides were immunohistochemically stained for anti-CD34 monoclonal antibody and anti-VEGF polyclonal antibody by SABC method. The intratumor microvessel density (IMVD) and the expression of vascular endothelial growth factor were measured. RESULT: 1. The mean IMVD with cervical lymphatic metastasis was significantly higher than those without cervical lymphatic metastasis in head and neck squamous cell carcinomas(27.92 +/- 9.11 and 20.69 +/- 7.08, P < 0.01); 2. The expression of vascular endothelial growth factor had a positive correlation with IMVD in head and neck carcinoma tissues (rs = 0.487, P < 0.01). CONCLUSION: IMVD may be an important predictor to cervical lymphatic metastasis in head and neck squamous cell carcinomas. Vascular endothelial growth factor may stimulate tumor angiogenesis in head and neck squamous cell carcinomas.

Adult↗
PubMed2003

[Melanoma antigen genes(MAGE) and malignant tumors].

The melanoma antigen genes(MAGE) were found to express in a variety of tumors of different histological origin. Peptides encoded by the MAGE genes are tumor rejection antigens, which can induce specific cytotoxic T-lymphocytes(CTL) to recognize and kill tumor cells. This lead to the idea of using MAGE genes as the targets for cancer immunotherapy. This article reviews the discovery, development, role, and therapeutic potential of MAGE tumor-associated antigens.

Antigens, Neoplasm↗
PubMed2002

A novel S-adenosyl-L-methionine:arsenic(III) methyltransferase from rat liver cytosol.

S-Adenosyl-l-methionine (AdoMet):arsenic(III) methyltransferase, purified from liver cytosol of adult male Fischer 344 rats, catalyzes transfer of a methyl group from AdoMet to trivalent arsenicals producing methylated and dimethylated arsenicals. The kinetics of production of methylated arsenicals in reaction mixtures containing enzyme, AdoMet, dithiothreitol, glutathione (GSH), and arsenite are consistent with a scheme in which monomethylated arsenical produced from arsenite is the substrate for a second methylation reaction that yields dimethylated arsenical. The mRNA for this protein predicts a 369-amino acid residue protein (molecular mass 41056) that contains common methyltransferase sequence motifs. Its sequence is similar to Cyt19, a putative methyltransferase, expressed in human and mouse tissues. Reverse transcription-polymerase chain reaction detects S-adenosyl-l-methionine:arsenic(III) methyltransferase mRNA in rat tissues and in HepG2 cells, a human cell line that methylates arsenite and methylarsonous acid. S-Adenosyl-l-methionine:arsenic(III) methyltransferase mRNA is not detected in UROtsa cells, an immortalized human urothelial cell line that does not methylate arsenite. Because methylation of arsenic is a critical feature of its metabolism, characterization of this enzyme will improve our understanding of this metalloid's metabolism and its actions as a toxin and a carcinogen.

Amino Acid Sequence↗
PubMed2002

Three-dimensional high-resolution magnetic resonance imaging of ocular and orbital malignancies.

BACKGROUND: Ultrathin-section 3-dimensional fast spin-echo (3-D FSE) T2-weighted imaging is a new magnetic resonance imaging (MRI) technique that we used in the evaluation of ocular and orbital malignancies. We evaluated the usefulness of this new technique compared with conventional MRI. METHODS: Imaging data from 26 consecutive patients seen in the Ocular Oncology Unit at the University of California-San Francisco were retrospectively reviewed by physicians from the ocular oncology and neuroradiology units. For all patients, 3-D FSE T2-weighted images (27 scans) were compared with results of conventional MRI and correlated with results of computed tomography (CT), A- and B-scan ultrasonography, ultrasound biomicroscopy, clinical examinations, and histopathology, when available. RESULTS: The 3-D FSE T2-weighted imaging sequence resulted in an overall improvement in accuracy of imaging findings in 17 (63%) of our 27 cases compared with the standard MRI protocol. The increased resolution led to the radiographic detection of additional lesions in 11 (41%) of 27 cases and to an increase in confidence in radiographic diagnosis in 6 (22%) of the remaining cases. The improved resolution of the 3-D FSE T2-weighted sequence resulted in a change of disease management in 3 (60%) of the 5 patients with nonretinoblastoma lesions. One hundred percent of active retinoblastoma lesions could be detected by means of 3-D FSE and conventional imaging; however, inactive lesions were not always detected using conventional imaging. CONCLUSIONS: The 3-D FSE T2-weighted sequence offers superior resolution of intraocular and orbital structures compared with conventional MRI. It is particularly useful in the evaluation of intraocular tumors and the nerve-sheath complex. This new technique contributes significantly to improved diagnosis and management in patients with ocular and orbital malignancies.

Eye Neoplasms↗
PubMed2002

The role of biomethylation in toxicity and carcinogenicity of arsenic: a research update.

Recent research of the metabolism and biological effects of arsenic has profoundly changed our understanding of the role of metabolism in modulation of toxicity and carcinogenicity of this metalloid. Historically, the enzymatic conversion of inorganic arsenic to mono- and dimethylated species has been considered a major mechanism for detoxification of inorganic arsenic. However, compelling experimental evidence obtained from several laboratories suggests that biomethylation, particularly the production of methylated metabolites that contain trivalent arsenic, is a process that activates arsenic as a toxin and a carcinogen. This article summarizes this evidence and provides new data on a) the toxicity of methylated trivalent arsenicals in mammalian cells, b) the effects of methylated trivalent arsenicals on gene transcription, and c) the mechanisms involved in arsenic methylation in animal and human tissues.

Animals↗
PubMed2002

[Express of human papillomavirus, P53 and H-ras gene in laryngeal cancer]

OBJECTIVE: To study the abnormality of p53 and H-ras gene in laryngeal cancer cells and their relation to the infection of human papillomavirus(HPV) subtypes. METHODS: The HPV subtypes, P53 and H-ras gene were examined in 28 cases of laryngeal cancer by polymerase chain reaction (PCR), single strand conformation polymorphism(SSCP), restriction fragment length polymorphism (RFLP) and DNA sequencing. RESULTS: P53 gene mutation existed in 50%cases of laryngeal cancer and DNA sequencing showed base substitution, insertion or deletion in 4 cases; The positive rate of the H-ras oncogene mutation was only 3.57% All high risk HPV infections (HPV-16 or-18) were distinctly seen in the cancer cases, especially in cases with P53 mutation. CONCLUSION: The high risk HPV subtype infection and P53 gene abnormality may play an important role in laryngeal cancer progression and these two factors may be correlated to each other.

Journal Article↗
PubMed2002

[Association of ecNOS 4 b/a polymorphism and end-stage chronic renal failure].

OBJECTIVE: To examine the association between insertion/deletion polymorphism in intron 4 of ecNOS gene (ecNOS 4 b/a) and end-stage chronic renal failure (ESCRF) in Han people in Tianjin, China. METHODS: The genotypes of ecNOS 4 b/a polymorphism were detected by PCR-minisatellite DNA detection technique. 67 CRF patients on hemodialysis were included in the study group, with 70 healthy volunteers as controls. RESULTS: (1) The genotype frequencies were 79.1%, 19.4% and 1.5% in the patients and 91.4%, 8.6% and 0% in the controls for bb, ba and aa genotypes, respectively. (2) The allele frequencies were significantly different between the patients and controls (chi(2) = 4.617, P < 0.05). The a/(a + b) odds ratio (OR, 95% confidence interval) of the patients vs controls was 2.64 (1.09, 6.43) (Z = 2.14, P < 0.05). (3) The average age of the patients with allele a was 47.43 +/- 11.63, while that without allele a was 58.08 +/- 13.68. The difference was significant, t = 2.664 (P < 0.01). (4) The frequency of allele a is lower in Han people of Tianjin (4.3%) than that in Japanese (10.1%) (chi(2) = 4.898, P = 0.027). CONCLUSIONS: (1) The frequency of allele a is lower in Han people of Tianjin than that in Japanese and Westeners; (2) ecNOS 4 b/a polymorphism is associated with ESCRF in Han population of Tianjin and allele a is associated with the increased risk of ESCRF.

Adult↗