PubMed Health⌕ Search

Biomedical subjects

M Y Lin

Publications and source records attributed to M Y Lin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Comparison of two molecular techniques for the detection of avian reoviruses in formalin-fixed, paraffin-embedded chicken tissues.

Reverse transcription (RT) in situ polymerase chain reaction (PCR) and in situ hybridization (ISH) techniques were used to detect the sigma c-encoded gene of avian reovirus (ARV) in chicken tissue sections. The advantage of using in situ methods is to make more rapid and accurate diagnosis of ARV infections. The sensitivity of these two techniques were compared. Of the two techniques, the RT in situ PCR test was found to be more sensitive than ISH and provided the rapid, sensitive, and specific detection of ARV infections.

Animals↗
PubMed1999

Identification of the sigma C-encoded gene of avian reovirus by nested PCR and restriction endonuclease analysis.

A nested reverse transcription (RT)-polymerase chain reaction with subsequent restriction endonuclease analysis was developed for identification of the sigma C-encoded gene of avian reoviruses (ARV). PCR products derived from the sigma C-encoded gene of all tested ARVs resulted in a specific DNA band of 1023 bp, indicating that there were no apparent insertions or deletions in this region. Amplification with the nested primer pairs S1M-S1N and S1P-S1N generated 330 and 239 bp, respectively. PCR products amplified from the sigma C-encoded of all tested ARVs isolates were further confirmed by Southern blot hybridization and restriction endonuclease analysis. PCR amplified cDNA fragment (1023 bp) cleaved with Pst I generated two fragments of 565 and 458 bp. The amplified sigma C-encoded gene of ARV was subcloned into PQE 32 vector for further study of its antigenicity and immunogenicity. The sensitivity of RT-PCR was examined on nucleic acids from the ARV infected cell cultures. The detection limit was 10(0) to 10(-1) TCID50 of ARV in a ethidium bromide stained gel and could be increased further to 10(-1) to 10(-2) TCID50 of ARV by Southern blot hybridization using a digoxigenin-labeled cDNA probe. The sensitivity increased approximately 10(3) to 10(4) folds when the cDNA was reamplified with two sets of nested primers.

Animals↗
PubMed1999

Attrition of T cell memory: selective loss of LCMV epitope-specific memory CD8 T cells following infections with heterologous viruses.

Using a variety of techniques, including limiting dilution assays (LDA), intracellular IFNgamma assays, and Db-IgG1 MHC dimer staining to measure viral peptide-specific T cell number and function, we show here that heterologous virus infections quantitatively delete and qualitatively alter the memory pool of T cells specific to a previously encountered virus. We also show that a prior history of a virus infection can alter the hierarchy of the immunodominant peptide response to a second virus and that virus infections selectively reactivate memory T cells with distinct specificities to earlier viruses. These results are consistent with a model for the immune system that accommodates memory T cell populations for multiple pathogens over the course of a lifetime.

Animals↗
PubMed1999

Antioxidative ability of lactic acid bacteria.

Nineteen strains of lactic acid bacteria were investigated for antioxidative activity. These includedLactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacterium longum B6 and 15 708. Intracellular cell-free extract of all strains demonstrated antioxidative activity with inhibition rates of ascorbate autoxidation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bacteria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe(2+), and B. longum 15 708 showed the highest Cu(2+) chelating ability among the 19 strains tested. All strains demonstrated reactive oxygen species scavenging ability. L. acidophilus E showed the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxide scavenging ability. Reducing activity was also found in all strains. Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enzyme inhibition, superoxide dismutase activity was not found in these 19 strains, and the activity of superoxide dismutase was not induced when metal ion Mn(2+), Fe(2+), or Cu(2+)Zn(2+) was present.

Antioxidants↗
PubMed1999

Inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum.

The inhibition of lipid peroxidation by Lactobacillus acidophilus and Bifidobacterium longum was investigated using two lipid model systems. All eight strains, including six strains of L. acidophilus and two strains of B. longum, demonstrated an inhibitory effect on linoleic acid peroxidation. The inhibitory rates on linoleic acid peroxidation ranged from 33 to 46% when 1 mL of intracellular cell-free extract was tested. In the second model system, the cell membrane of osteoblast was used as the source for biological lipid. The results indicated that all strains were able to protect biological lipids from oxidation. The inhibition rates on cell membrane lipid peroxidation ranged from 22 to 37%. The effect of L. acidophilus and B. longum on inhibition of fluorescent tissue pigment accumulation was also obtained for osteoblastic cells. The inhibition rates on fluorescent tissue pigment accumulation ranged from 20 to 39%. The antioxidative effect of each milliliter of intracellular cell-free extract of L. acidophilus and B. longum was equivalent to 104-172 ppm of butylated hydroxytoluene (BHT). These results indicated that all strains demonstrated high antioxidative activity. The scavenging ability of lipid peroxidation products, tert-butyl hydroperoxide and malondialdehyde, was also evaluated. The results showed that L. acidophilus and B. longum were not able to scavenge the tert-butyl hydroperoxide. Nevertheless, malondialdehyde was scavenged well by these strains.

Animals↗
PubMed1999

Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

Antioxidants↗
PubMed1998

Stability and diversity of T cell receptor repertoire usage during lymphocytic choriomeningitis virus infection of mice.

Numerous studies have examined T cell receptor (TCR) usage of selected virus-specific T cell clones, yet little information is available regarding the stability and diversity of TCR repertoire usage during viral infections. Here, we analyzed the Vbeta8.1 TCR repertoire directly ex vivo by complementarity-determining region 3 (CDR3) length spectratyping throughout the acute lymphocytic choriomeningitis virus (LCMV) infection, into memory, and under conditions of T cell clonal exhaustion. The Vbeta8 population represented 30-35% of the LCMV-induced CD8(+) T cells and included T cells recognizing several LCMV-encoded peptides, allowing for a comprehensive study of a multiclonal T cell response against a complex antigen. Genetically identical mice generated remarkably different T cell responses, as reflected by different spectratypes and different TCR sequences in same sized spectratype bands; however, a conserved CDR3 motif was found within some same sized bands. This indicated that meaningful studies on the evolution of the T cell repertoire required longitudinal studies within individual mice. Such longitudinal studies with peripheral blood lymphocyte samples showed that (a) the virus-induced T cell repertoire changes little during the apoptosis period after clearance of the viral antigens; (b) the LCMV infection dramatically skews the host T cell repertoire in the memory state; and (c) continuous selection of the T cell repertoire occurs under conditions of persistent infections.

Animals↗
PubMed1998

Differential surface accessibility of alpha(187-199) in the Torpedo acetylcholine receptor alpha subunits.

We have probed the surface accessibility of residues alpha187 to alpha199 of the Torpedo acetylcholine receptor with monoclonal antibody 383C, which binds uniquely to these residues. However, 383C binds to only one of the two alpha subunits in the membrane-bound receptor, neither of the two subunits in carbamylcholine-desensitized receptor, and to both alpha subunits in Triton X-100 solubilized receptor. The kinetics of association and dissoci-ation of 383C with the peptide alpha(183-199) compared to those with the membrane-bound receptor suggest that all but a single hydrogen bond of affinity derives from contacts between this peptide and the monoclonal antibody paratope. Inhibition of 383C binding by alpha-bungarotoxin selectively directed to the alpha subunit correlated with the high-affinity d-tubocurarine binding site, along with a lack of inhibition by alpha-bungarotoxin directed to the alpha subunit correlated with the low-affinity d-tubocurarine binding site, suggests that the 383C epitope on the membrane-bound receptor resides on the alpha subunit associated with the high-affinity d-tubocurarine binding site. The results presented here suggest a structural basis for the differences between the two receptor acetylcholine binding sites.

Animals↗
PubMed1998

Management of lactose maldigestion by consuming milk containing lactobacilli.

The influence of nonfermented milk containing L. acidophilus or L. bulgaricus on lactose utilization by lactose maldigesters was investigated. Nonfermented milks containing L. acidophilus or L. bulgaricus at 10(8) and 10(9) CFU/ml were prepared using 2% low-fat milk. Lactose maldigestion was monitored by measuring breath hydrogen at hourly intervals for 8 hr following consumption of 400 ml of each diet. Nonfermented milk containing L. acidophilus B at 10(8) CFU/ml were not effective in reducing breath hydrogen and symptoms. Nonfermented milk containing L. acidophilus B at 10(9) CFU/ml only slightly decreased breath hydrogen production; however, the symptoms were significantly improved. Nonfermented milks containing L. bulgaricus 449 at 10(8) and 10(9) CFU/ml were effective in reducing breath hydrogen and symptoms. The results for bulgaricus milk were all significant. In this study, L. acidophilus B and L. bulgaricus 449 were chosen because of their similar beta-galactosidase activity and bile sensitivity. L. acidophilus and L. bulgaricus are both thermophilic lactobacilli and an active transport (permease) system is found in both species for lactose transport. The major factor affecting in vivo lactose digestion in this study appears to be the bacterial cell wall/membrane structures. That the cell wall/membrane structures of L. acidophilus are different from those of L. bulgaricus can be indirectly proven by the results of sonication time for maximum beta-galactosidase activity measurement. The results of this study indicate that L. bulgaricus is usually a better choice than L. acidophilus for manufacturing nonfermented milks for lactose maldigesters.

Animals↗
PubMed1997

Surgical treatment of pediatric lung abscess.

Eight pediatric patients with lung abscesses underwent surgical intervention in our hospital during a 7-year period. All the abscesses were associated with severe sepsis or complicated by a bronchopleural fistula that did not respond to medical treatment and tube thoracostomy. Seven patients required unilateral thoracotomies, and one patient with bilateral lesions required simultaneous bilateral thoracotomies. One tension pneumatocele required a preceding pneumonostomy. All patients underwent decortication and at least one additional surgical procedure consisting of: lung debridement plus bronchial closure (n = 4); lobectomy (n = 2); bisegmentectomy (n = 3); and/or segmentectomy (n = 1). There were no operative deaths, but two patients had persistent air leakage that was treated by bronchial closure. The average hospital stay was 22 days (postoperative 10.1 days). All the patients recovered completely. For many pediatric lung abscesses that do not respond to medical treatment and simple drainage procedures, surgical intervention is indicated and can shorten the hospital stay.

Bronchial Fistula↗
PubMed1997

Surgical results of 23 patients with tracheobronchial injuries.

The objective of this study was to evaluate the surgical results of tracheobronchial injuries. Between July 1988 and March 1996, tracheobronchial surgery was performed on 23 injured patients. According to the aetiology, the injuries were categorized as blunt injury (n = 13), cutting or penetrating injury (n = 5), and corrosive injury (n = 5). Blunt injuries included three complete laryngotracheal disruptions, one tracheal laceration, and eight bronchial ruptures. Cutting or penetration injuries included four laryngotracheal ruptures and one tracheal cutting wound. Corrosive injuries included one tracheal necrosis, one tracheal stenosis and three esophagorespiratory fistulae. Operative procedures that were performed on the tracheobronchus included tracheoplasty (n = 12), bronchoplasty (n = 7), sleeve resection of the trachea (n = 2) and bronchus (n = 2). Two hospital deaths were encountered, with a mortality rate of 8.7%. One patient with caustic injury died of bronchopleural fistula and empyema. The other patient died with multiple injuries from multiple organ failure which was unrelated to the bronchoplasty. One postoperative complication was restenosis of the trachea in a caustic injured patient, which was treated by a T-tube insertion. In conclusion, tracheobronchoplasty is an effective life-saving emergency procedure for the patients with tracheobronchial injuries.

Adult↗
PubMed1997

Surgical results of 29 patients with benign tracheobronchial lesions.

This study was carried out in order to evaluate the surgical results of benign tracheobronchial diseases. Between July 1988 and March 1996, tracheobronchial surgery was performed on 29 patients with a variety of benign diseases. The primary diseases were post intubation or post tracheostomy tracheal stenosis (n = 12), tuberculous stenosis (n = 7), congenital tracheal stenosis with or without vascular ring (n = 4), tracheobronchial tumour (n = 2), oesophageal tumour (n = 1), and miscellaneous conditions (n = 3). Thirty-one operative procedures included sleeve lobectomy (n = 7), sleeve resection of trachea (n = 17) and bronchus (n = 2), and plastic surgery of trachea (n = 4) and bronchus (n = 1). There was one operative death, which put the mortality rate at 3.4%. There were five postoperative complications in this series (17.2%), including anastomotic disruption of trachea (n = 1), bilateral vocal cord palsy (n = 1), prolonged endotracheal intubation (n = 1) and overgrowth of granulation (n = 2). The complication of anastomotic disruption of trachea was treated by insertion of a tracheal T-tube, and the granulation was treated by bronchoscopic excision. We suggest that tracheobronchoplasty is a safe procedure in carefully selected patients with benign diseases.

Adolescent↗
PubMed1997

Surgical results of 40 patients with malignant tracheobronchial lesions.

The objective of this study was to evaluate the results of tracheobronchoplastyperformed on a variety of malignant diseases which involved the tracheobronchus. Between July 1988 and March 1996 tracheobronchial surgery was performed on 40 patients who had a variety of malignant diseases. The primary diseases were bronchogenic carcinoma (n=26), tracheobronchial tumour (n=5), thyroid cancer (n=6), and oesophageal cancer (n=3). Operative procedures that were performed on the tracheobronchus were sleeve lobectomy (n=22) or bilobectomies (n=5), sleeve pneumonectomy (n=3), sleeve resection of trachea (n=7) and bronchus (n=3). There was one postoperative death with a mortality rate of 2.5%. However, there were no significant postoperative complications apart from the one postoperative death; one patient developed a bronchopleural fistula and empyema. In lung cancer patients, the 2 year survival rate was 47.3%, and one (3.8%) local tumour recurrence. Four of five patients who had tracheobronchial tumours were alive and free from disease during 2-6 year follow-up period. One patient who had malignant fibrous histiocytoma died of brain metastasis 6 months after the operation. Among six patients whose thyroid cancer involved the trachea, one patient survived for 7 years, the other five patients were still alive and free from disease 2-5 years after the operation. Of the three patients whose oesophageal carcinoma involved the tracheobronchus, there was one operative death and the others died of tumour recurrence 1 and 2 years, respectively. We suggest that tracheobronchoplasty is a safe procedure with low morbidity and mortality rates in carefully selected patients with malignant diseases.

Adolescent↗