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Biomedical subjects

M Lin

Publications and source records attributed to M Lin.

At least 181 records · Page 10Linked to original sources
PubMed1998

[Expression of bcl-2 gene in human trabecular cells induced by dexamethasone].

PURPOSE: To investigate the influence of dexamethasone on expression of bcl-2 gene in human trabecular cells. METHODS: The trabecular specimens from human eyes were cultured in vitro and the cultured cells of the third generation on slides were immersed in culture solution containing 10(-7) M dexamethasone for 6 hours, 12 hours and 24 hours respectively. The expression of bcl-2 gene was studied with LSAB. RESULTS: The positive cells of the bcl-2 protein could be identified after dexamethasone effected for 6 hours and the positive cell increased with time going on. CONCLUSION: The expression of bcl-2 gene can be induced by dexamethasone, it may be related with glaucomatic pathogenesis.

Apoptosis↗
PubMed1998

The study on culture and ultrastructure of glaucomatous trabecular cells in vitro.

PURPOSE: To establish the culture system of human glaucomatous trabecular cells in vitro and study their ultrastructures. METHODS: The trabecular specimens from trabeculectomy were cultured in vitro and passaged 3 times, then identified. Moreover, the glaucomatous cells were observed with electron microscope while compared with the normal ones. RESULTS: Cultured human glaucomatous trabecular cells were obtained. The ultrastructure of the cells showed the decrease in vilious project, coated vesicle and lysosomal inclusion. CONCLUSION: The establishment of human glaucomatous trabecular cells culture in vitro made the culture system more perfect. The morphologic changes might be related to the abnormal functions of human trabecular meshwork cells.

Cell Division↗
PubMed1998

[The study on the culture, freezing preservation and resuscitation of human trabecular cells in vitro].

PURPOSE: To establish the culture of human trabecular cells in vitro and study the freezing preservation and resuscitation. METHODS: The trabecular specimens from human eyes were cultured in vitro and passaged 3 times, then the cultured cells were frozen and preserved. The frozen cells were resuscitated after one week, two weeks, one month and two months. RESULTS: Cultured human trabecular cells were obtained. The frozen cells were resuscitated successfully. All of the resuscitated rates were more than 90%. CONCLUSION: The human trabecular cells were cultured in vitro successfully, they can also be frozen and resuscitated, which will be helpful to the establishment of cDNA library and the screening of associated glaucomatous genes.

Cell Division↗
PubMed1998

Distribution patterns of inflammatory sinonasal diseases.

BACKGROUND/AIM OF STUDY: There has been an increase in the demand for coronal sinus CT scan since the introduction of functional endoscopic sinus surgery; as the information provided by the scans assist the surgeon in the pre-operative plannings. Babbel and colleagues had demonstrated five distinctive patterns of recurring inflammatory sinonasal disease on CT scan. The aim of this study was to evaluate the patterns in the local population and to see if there was a difference compared to the Caucasian population. METHODS AND MATERIALS: A retrospective review of 302 scans done between March 1993 and September 1995 was carried out. All scans were carried out using a 5 mm thickness to cover the posterior sinuses and a 3 mm thickness to cover the anterior sinuses. The scans were then grouped into the various patterns and an analysis was carried out comparing the differences in the patterns between the Chinese and the non-Chinese, and between the local population and the Caucasian population in Babbel's series. RESULTS: There was no significant difference between the Chinese and the non-Chinese in the distribution of the various disease patterns. When compared to the Caucasian population, the local population had more sinonasal polyposis and sphenoethmoidal recess obstruction. CONCLUSION: The smaller nasal passages of the Asians, particularly in the Chinese, could be the reason for the more prevalence of Type III and Type IV disease compared to the Caucasian population. The more constant and frequent exposure to allergens might also contribute to the increased prevalence of Type IV disease.

Adolescent↗
PubMed1998

Reliability of the MOS SF36 health status measure in Australian general practice.

OBJECTIVE: Past studies suggest that the MOS SF36 holds promise as a useful instrument to assess health outcomes. Although it is being promoted for use in general practice, it is important first to examine its reliability in this setting. METHOD: A consecutive sample of 64 adult patients were recruited from an experienced general practitioner's waiting room in metropolitan Sydney. They were asked to complete identical questionnaires containing the Medical Outcomes Study (MOS) SF36 mailed to them on two separate occasions. RESULTS: There was a 66% response rate for both Time 1 and Time 2 surveys resulting in 64 paired questionnaires with high item completion rates (95-100%). The results demonstrated high internal consistency for both tests (Cronbach's a > 0.87). The reliability coefficients ranged from 0.59 to 0.89 across scales. CONCLUSIONS: This study provides support for the psychometric stability of the MOS SF36 as quality of life measure for patients in general practice. However, a large study is required to establish much needed normative ranges for self administered instruments in general practice.

Adolescent↗
PubMed1998

Analysis of cell death in myeloid cells inducibly expressing the cell cycle protein p55Cdc.

p55Cdc, a cell cycle protein is expressed in cycling mammalian cells and is required for normal cell division. Expression of this protein is regulated during the cell cycle, peaking in late G1 and S. We have previously shown that constitutive expression of p55Cdc results in inhibition of granulocyte differentiation. Degradation of p55Cdc is also required for apoptosis in growth factor and serum starved cells. In the present study we prepared stably transfected cells conditionally expressing p55Cdc in response to zinc stimulation to investigate the role of inducible p55Cdc expression in apoptosis of myeloid cells. We report that inducible expression of p55Cdc in the myeloid leukemic cell line 32Dc13 resulted in increased cell death. p55Cdc overexpression led to a statistically significant decrease in the viability of 32Dc13 cells compared with that of control cells. Furthermore, cell staining and flow cytometry analysis revealed that p55Cdc-overexpressing 32Dc13 cells progressed to apoptosis much earlier than uninduced cells. These results suggest that inducible expression of p55Cdc leads to earlier increases in cell death in the absence of growth factor and serum in myeloid leukemic cells.

Animals↗
PubMed1997

Response to second-line chemotherapy in patients with metastatic breast carcinoma previously responsive to first-line treatment: prognostic factors.

BACKGROUND: The aim of this retrospective study was to determine those prognostic factors associated with response to a second-line chemotherapy in patients with metastatic breast carcinoma (MBC) that was previously responsive to a first-line chemotherapy. METHODS: The 70 MBC patients studied had previously responded to a first-line chemotherapy, mainly anthracycline or anthracenedione-containing regimens. During first-line chemotherapy they had received treatment until the maximum response was obtained, at which time treatment was discontinued. Second-line chemotherapy regimens were of several types (48.5% with anthracycline). A study of prognostic factors associated with response to second-line chemotherapy was performed by univariate and multivariate analysis. RESULTS: Second-line chemotherapy achieved a 44% response rate, with a median response duration of 10 months. Survival was 13 months in the entire patient group, 22 months in responders, and 8 months in nonresponders. Univariate analysis identified seven factors related to patient response rate to second-line treatment. A better response rate to second-line chemotherapy was observed in patients with the following features: 1) chemotherapy free time (time between onset of metastatic disease and initiation of first-line) < 12 months (P = 0.03); 2) complete response to first-line chemotherapy (P = 0.013); 3) response duration to first-line chemotherapy > 14 months (P = 0.0001); 4) progression free interval (time between end of first-line treatment and initiation of second-line chemotherapy) > 11 months (P = 0.0001); 5) performance status at second-line treatment < 2 (P = 0.04); 6) tumor index at second-line chemotherapy < 4 (P = 0.05); and 7) treatment with an anthracycline-containing second-line regimen (P = 0.03). In multivariate analysis, only progression free interval was identified as being associated with response rate to second-line chemotherapy (P = 0.0001). CONCLUSIONS: Retained chemosensitivity appeared to be an important characteristic in patients responding to second-line chemotherapy.

Adult↗
PubMed1997

A novel, testis-specific mRNA transcript encoding an NH2-terminal truncated nitric-oxide synthase.

mRNA diversity represents a major theme of neuronal nitric-oxide synthase (nNOS) gene expression in somatic cells/tissues. Given that gonads often express unique and biologically informative variants of complex genes, we determined whether unique variants of nNOS are expressed in the testis. Analysis of cDNA clones isolated from human testis identified a novel, testis-specific nNOS (TnNOS) mRNA transcript. A predicted 3294-base pair open reading frame encodes an NH2-terminal truncated protein of 1098 amino acids. Measurement of calcium-activated L-[14C]citrulline formation and nitric oxide release in CHO-K1 cells stably transfected with the TnNOS cDNA indicates that this protein is a calcium-dependent nitric-oxide synthase with catalytic activity comparable to that of full-length nNOS. TnNOS transcripts exhibit novel 5' mRNA sequences encoded by two unique exons spliced to exon 4 of the full-length nNOS. Characterization of the genomic structure indicates that exonic regions used by the novel TnNOS are expressed from intron 3 of the NOS1 gene. Although lacking canonical TATA and CAAT boxes, the 5'-flanking region of the TnNOS exon 1 contains multiple putative cis-regulatory elements including those implicated in testis-specific gene expression. The downstream promoter of the human nNOS gene, which directs testis-specific expression of a novel NH2-terminal truncated nitric-oxide synthase, represents the first reported example in the NOS gene family of transcriptional diversity producing a variant NOS protein.

Alternative Splicing↗
PubMed1997

Linkage studies suggest a possible locus for bipolar disorder near the velo-cardio-facial syndrome region on chromosome 22.

Velo-cardio-facial syndrome (VCFS) is a congenital anomaly characterized by multiple dysmorphisms, cleft palate, cardiac anomalies, and learning disabilities, that results from a microdeletion of chromosome 22q11. An increased prevalence of psychiatric illness has been observed, with both schizophrenia and bipolar disorder commonly being diagnosed. For these reasons, the VCFS region is an interesting candidate region for bipolar disorder. We examined this region in 17 bipolar families from three populations: 13 families from the general North American population (University of California, San Diego/University of British Columbia, UCSD/UBC), three larger families from New York, and a portion of Old Order Amish pedigree 110. Three microsatellite markers spanning 13 cM around the VCFS region were genotyped in all the families. A maximum lod score of 2.51 was obtained in the UCSD/UBC families under a dominant model at D22S303. In the combined family set, maximum lod scores of 1.68 and 1.28 were obtained at this marker under dominant and recessive models, respectively. Four additional markers were subsequently typed in selected positive families, and yielded positive lods at 6 of 7 markers spanning 18 cM in this region. Nonparametric, multipoint analyses using the affected pedigree member (APM) method also yielded suggestive evidence for linkage in both the UCSD/UBC family set (P = 0.0024) and in the combined families (P = 0.017). Affected sibpair analyses were similarly positive in the UCSD/UBC families (P = 0.017), and in the combined families (P = 0.004). These results are suggestive of a possible locus for bipolar disorder near the VCFS region on chromosome 22.

Abnormalities, Multiple↗
PubMed1997

Long-term potentiation and depression in layer III and V pyramidal neurons of the cat sensorimotor cortex in vitro.

Synaptic plasticity of the cat sensorimotor cortex was examined intracellularly in vitro. After tetanic stimulation of the white matter, layer III and V pyramidal neurons showed long-term potentiation (LTP) of EPSPs in high incidence without GABA(A) antagonist. The incidence and magnitude of LTP were very conspicuous in layer V cells. After an NMDA receptor antagonist application, the synaptic potentiation was blocked completely in layer III but not in layer V cells. Long-term depression (LTD) of the evoked EPSPs was also induced by the same stimulation in some layer III cells, where a transient hyperpolarization of the membrane potential was observed during tetanus.

2-Amino-5-phosphonovalerate↗
PubMed1997

The genomic structure of a mouse seminal vesicle autoantigen.

The genomic structure of an androgen-stimulated mouse seminal vesicle autoantigen was determined. Analysis of the nucleotide sequence established 2135 bp of the 5'-flanking region, four exons of 123, 136, 112, 227 bp, three introns of 1555, 1931, 316 bp, and 185 bp of the 3'-flanking region of this gene. Ten DNA segments, five in the 5'-flanking region, two in the first intron, and three in the second intron were identified to have more than 50% homology with the consensus sequence of the androgen response element (ARE). Two sets of adjacent DNA segments, one including -213 to -199 bp and -124 to -110 bp in the 5'-flanking region and the other including 2532 to 2546 bp and 2582 to 2596 bp in the second intron, are noticeable for their high degree of homology with ARE.

Androgens↗
PubMed1997

Binding of the Brucella abortus lipopolysaccharide O-chain fragment to a monoclonal antibody. Quantitative analysis by fluorescence quenching and polarization.

An antigenic O-chain polysaccharide fragment derived from Brucella abortus lipopolysaccharide was labeled with 14.8 +/- 1.8 (n = 5) and 52.3 +/- 2.4 (n = 3) micromol of fluorescein/g of polysaccharide (designated FL1 and FL2, respectively) for use in investigating the binding of O-chain to a specific murine antibody YsT9 under equilibrium conditions. Upon binding to YsT9, the fluorescence of FL1 and FL2 was quenched 45-57% with no shift in the excitation and emission spectra, and polarization of fluorescence increased by 300-335%. With fluorescence quenching and polarization as sensitive signals for antibody-bound labeled O-chains, the equilibrium constants for binding of FL1, FL2, and unlabeled O-chain to YsT9 were determined to be within a similar order (1.5 x 10(7) to 2.0 x 10(7) M-1) using a nonlinear curve fitting approach rather than Scatchard analysis. These results indicated that covalent attachment of fluorescein groups to the O-chain did not influence the recognition of the YsT9-defined epitope by the antibody. The reversibility of the O-chain-antibody reaction was also demonstrated by showing a rapid depolarization of the labeled O-chain-antibody complex in the presence of unlabeled O-chain, suggesting that this displacement experiment could be exploited to quantify the Brucella polysaccharide antigen. The study described here provides a useful model for characterization of the complex formation between a carbohydrate-binding protein and a carbohydrate ligand and also for the design of a homogeneous assay system to quantitate antigens or antibodies of clinical interest.

Animals↗
PubMed1997

Control of G1 in the developing Drosophila eye: rca1 regulates Cyclin A.

In the developing eye of Drosophila melanogaster, cells become synchronized in the G1 phase of the cell cycle just prior to the onset of cellular differentiation and morphogenesis. In roughex (rux) mutants, cells enter S phase precociously because of ectopic activation of a Cyclin A/Cdk complex in early G1. This leads to defects in cell fate and pattern formation, and results in abnormalities in the morphology of the adult eye. A screen for dominant suppressors of the rux eye phenotype led to the identification of mutations in cyclin A, string (cdc25), and new cell cycle genes. One of these genes, regulator of cyclin A (rca1), encodes a novel protein required for both mitotic and meiotic cell cycle progression. rca1 mutants arrest in G2 of embryonic cell cycle 16 with a phenotype very similar to cyclin A loss of function mutants. Expression of rca1 transgenes in G1 or in postmitotic neurons promotes Cyclin A protein accumulation and drives cells into S phase in a Cyclin A-dependent fashion.

Amino Acid Sequence↗
PubMed1997

Effects of exposure to carbon disulfide (CS2) on electrocardiographic features of ischemic heart disease among viscose rayon factory workers.

The objective of the study was to evaluate viscose plant workers for electrocardiographic manifestations resulting from exposure to carbon disulfide (CS2). A total of 162 workers (118 in an exposure group and 44 in a reference group) were evaluated using a health questionnaire, physical check-up, biochemical analysis of blood samples and electrocardiograms (ECG). The exposure group consisted of workers in the following areas: viscose manufacturing, cellophane processing, ripening, and filament spinning. Reference group workers were from the administrative office, rolling area, pulp processing, and testing office. Only slight differences were found in the biochemical analyses of the two groups, with the exception of sodium (Na) levels. Personal and area sampling results were found to have a high variation due to different locations within the plant and a wide range of manufacturing processes. Highest CS2 concentrations were found in the ripening area (54.60 ppm) and the filament spinning area (19.60 ppm). Using a multiple logistic regression model to control variables (age, gender, body mass index, duration of employment, cholesterol, smoking, and alcohol), we found a relative risk for ECG abnormalities 4.18 times significantly higher for the exposure group. The authors feel that the installation of an adequate ventilation system could greatly reduce the risk of workers developing CS2-induced cardiovascular abnormalities.

Adult↗
PubMed1997

Delta-opiate DPDPE in magnetically oriented phospholipid micelles: binding and arrangement of aromatic pharmacophores.

D-Penicillamine(2,5)-enkephalin (DPDPE) is a potent opioid peptide that exhibits a high selectivity for the delta-opiate receptors. This zwitterionic peptide has been shown, by pulsed-field gradient 1H NMR diffusion studies, to have significant affinity for a zwitterionic phospholipid bilayer. The bilayer lipid is in the form of micelles composed of dihexanoylphosphatidylcholine (DHPC) and dimyristoylphosphatidylcholine (DMPC) mixtures, where the DMPC forms the bilayer structure. At high lipid concentration (25% w/w) these micelles orient in the magnetic field of an NMR spectrometer. The resulting 1H-13C dipolar couplings and chemical shift changes in the natural abundance 13C resonances for the Tyr and Phe aromatic rings were used to characterize the orientations in the bilayer micelles of these two key pharmacophores.

Biophysical Phenomena↗
PubMed1997

A mechanistic study of griseofulvin dissolution into surfactant solutions under laminar flow conditions.

The in vivo dissolution of many poorly soluble drugs is enhanced by the action of surfactants secreted into the upper gastrointestinal (GI) tract. These substances may act by solubilizing individual drug molecules into two separate liquid phases: the free aqueous phase and a micellar phase in which the drug is incorporated into a complex of two or more surfactant molecules. This complex process, micellar solubilization, was the subject of this in vitro study, wherein griseofulvin (gris) dissolution was observed in flowing surfactant solutions. Aqueous solutions of sodium dodecyl sulfate (SDS), an anionic surfactant, were pumped over a gris tablet embedded in a laminar flow device to simulate flow in the human upper GI tract. SDS solutions were well above the critical micellar concentration (cmc approximately 6-7 mM), and flow rates ranged from 4 to 7 mL/min. Gris solubility in premicellar (4 mM), near-micellar (6 mM), and micellar (>6 mM) SDS solutions was also determined. The measured solubility of gris increased linearly with SDS concentrations above the cmc. Drug solubility in SDS concentrations below the cmc was also higher than that in water. Gris diffusion coefficients were measured using pulsed-field gradient NMR spectroscopy. To determine the controlling mechanism for surfactant-enhanced dissolution, a mathematical model was developed. The model solution, an equation for drug dissolution rate, was compared with experimental data to demonstrate that drug transport away from the solid surface is the slow step in the process. Measured gris diffusion coefficients and solubility values were used as constants in the mathematical model solution and were combined to calculate an effective gris diffusion coefficient. Using these experimentally determined properties, model-calculated dissolution rates were within 7% of the measured values. As hypothesized, dissolution rates were found to be directly proportional to the transport properties of the system (effective drug diffusion coefficient and fluid flow rate) as well as to the drug solubility. To further verify transport-limited dissolution, the measured dissolution rates were found to be proportional to the surrounding medium flow rate to the 1/3 power, as predicted by the model dissolution rate equation.

Antifungal Agents↗
PubMed1997

Heterogeneity of the human H blood group alpha(1,2)fucosyltransferase gene among para-Bombay individuals.

BACKGROUND AND OBJECTIVES: The para-Bombay phenotype has a relatively high frequency of about 1 in 8,000 Taiwanese. Studies were carried out on eight healthy and unrelated Taiwanese with the para-Bombay phenotype to cast light on its immunogenetic basis. MATERIALS AND METHODS: Blood and saliva samples were tested with standard hemagglutination techniques. Salivary ABH substances were determined by hemagglutination inhibition. PCR techniques were used to amplify the coding region of the H genes. RESULTS: Five different h alleles, designated as h1, h2, h3, h4 and h5, were identified in the Taiwanese with the para-Bombay phenotype. The h1 allele loses one of the three AG repeats located at the nucleotides 547-552 of the H gene, whereas two of the three T repeats located at the nucleotides 880-882 are deleted in the h2 allele. The h3 allele contains a C658 to T missense mutation, whereas two missense mutations, C35 to T and A980 to C were identified in the h4 allele. A T460 to C missense is present in the h5 allele. The h5 allele was identified in an individual whose red blood cells contain blood group A antigen but not H antigen, and thus may be considered a weak variant of the H gene. CONCLUSIONS: So far no biologic relevance of the H antigen has been discovered, and its deficiency does not seem to produce any deleterious effects. There may be better understanding of the evolutionary basis for the polymorphisms at these loci after systematic study of different ethnic populations.

ABO Blood-Group System↗