Biomedical subjects

M Y Lin

Publications and source records attributed to M Y Lin.

At least 19 recordsLinked to original sources

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↗

PubMed1997

Alpha beta and gamma delta T-cell networks and their roles in natural resistance to viral infections.

Both alpha beta and gamma delta T-cell populations and natural killer (NK) cells include cytotoxic, interferon (IFN)-gamma-producing lymphocytes that actively respond to viral infections. We show here that all three populations can provide "natural resistance" to viruses very early in infection and describe how the T-cell populations are modulated to provide this function. gamma delta T cells were shown to play a role in controlling vaccinia virus (VV) infections, as VV grew to much higher titers in gamma delta T-cell knockout mice than in normal mice 3-4 days post-infection. Our studies of the alpha beta T-cell responses to viruses revealed an interactive network of T cells that is modulated substantially during systemic infections. There is an induction phase associated with a massive virus-specific CD8 T-cell response, an apoptosis phase during which the T cells become sensitized to activation-induced cell death (AICD), a silencing phase, during which the T-cell number and activation state is reduced, and, finally, a memory phase associated with the very stable preservation of virus-specific memory cytotoxic T-lymphocyte precursors (pCTL). Infection of mice immune to one virus with a heterologous virus leads to a selective expansion of memory CTL cross-reacting between the two viruses, but, after homeostasis is again established, there is a quantitative reduction and qualitative alteration of memory to the first virus. Our results suggest that memory alpha beta T cells cross-reactive between heterologous viruses mediate both immunopathology and protective immunity at early stages of the second virus infection. Thus, memory alpha beta T cells can, like gamma delta T cells and NK cells, provide natural immunity to viral infections.

Animals↗

PubMed1996

Construction of an integrative food-grade cloning vector for Lactobacillus acidophilus.

An integrative cloning vector was constructed using a randomly cloned HindIII-digested chromosomal fragment from Lactobacillus acidophilus ADH inserted into an Escherichia coli vector, pBluescript II SK+. Southern hybridization studies demonstrated homology of the inserted fragment with one other L. acidophilus strain and one Bifidobacterium strain. Identification of a SauI site located near the middle of the 1.9-kb ADH chromosomal fragment made it possible to clone the Lactobacillus bulgaricus beta-galactosidase (EC 3.2.1.23) gene into this vector. The vector was unable to replicate in the homologous host, L. acidophilus ADH, following electroporation. The chromosomal fragment allowed the integration of the beta-galactosidase gene (beta gal) into the host chromosome via homologous recombination. The size of the two flanking L. acidophilus ADH chromosomal fragments, approximately 0.95 kb each, was sufficient to allow the double cross-over to take place. Southern hybridization demonstrated that only L. acidophilus and L. bulgaricus DNA had been integrated into the chromosome of the host strain. The beta-galactosidase activity of the transformant was increased approximately 200-fold when compared to the enzyme activity of the wild-type strain. The beta gal gene remained stable in the transformant strain after 30 transfers in growth media without selection pressure. This first-generation integrative cloning vector is constructed solely of DNA from organisms consumed by humans and could be considered a food-grade vector system.

Bacterial Proteins↗

PubMed1996

Results of surgical treatment of 107 patients with complications of pulmonary tuberculosis.

The objective of this study was to evaluate the results of surgical intervention performed on 107 patients with pulmonary tuberculosis complications. Between September 1988 and December 1995, 107 patients underwent a total of 126 operations for major complications of pulmonary tuberculosis. One hundred and twenty-six operations consisted of lobectomies only or plus other lung resections performed in 55 cases, pneumonectomies in 20 cases, segmentectomies in 18 cases, wedge resections in two cases, tracheobronchoplasties in four cases, decortications in two cases, cavernostomies with concomitant muscle transpositions in seven cases, thoracoplasties reserved for the previously failed operations or to be a supplement for pulmonary resections in 18 cases. The operative mortality rate was of 1.8%, and the major complication rate was of 16.8%. Twenty-eight (26.1%) patients with tuberculosis bacilli in sputum before operation have converted except one diabetic patient. In conclusion, surgery is indicated in pulmonary tuberculosis complications that are life-threatening or unresponsive to chemotherapy. Pulmonary resection is the procedure of choice for most cases that require surgery.

Adolescent↗

PubMed1996

Functional evaluation of esophageal substitutes.

BACKGROUND: The function of esophageal Substitutes is not comparable to the normal esophagus. METHODS: To clarify the difference between esophageal substitutes and the normal esophagus, radionuclide scintigraphy and clinical assessment were used as study methods. The study was conducted in groups of substernal colon (n = 9), substernal ileocolon (n = 6), posterior mediastinal colon (n = 6) and posterior mediastinal gastric tube (n = 14). The control group consisted of normal volunteers (n = 8). RESULTS: Patients with substernal ileocolon did not experience nocturnal regurgitation, which occurred often in other groups. All esophageal substitutes had a decreased clearance ability compared to the normal esophagus. Among these substitutes, the posterior mediastinal gastric tube had the shortest swallowing time, while the substernal ileocolon had the longest. The substernal colon had a significantly prolonged transit time. Among these study groups, neither differences of clearance ability nor those of alimentary reflux reached statistical significance. CONCLUSIONS: From the view point of food transit, it is suggested that a posterior mediastinal gastric tube or posterior mediastinal colon is the first choice of esophageal substitute.

Adult↗

PubMed1995

Bronchial rupture caused by blunt chest injury.

We have surgically treated six patients with bronchial rupture caused by blunt chest injury in the past 5 years. All injuries resulted from traffic accidents, except in one patient who was hit by a crane. Clinical manifestations included chest pain (n = 6), subcutaneous emphysema (n = 4), and dyspnea (n = 6). Roentgenographic findings were tension (n = 3) or nontension (n = 3) pneumothorax, subcutaneous emphysema (n = 4), pneumomediastinum (n = 3), deep cervical emphysema (n = 5), and delayed collapse of the affected lung (n = 3). Three patients had associated injuries: right clavicle and rib fractures in the first; right humeral, scapular, and multiple rib fractures and left sternoclavicular joint dislocation in the second; and left clavicle fracture in the third. These six patients all underwent immediate tube thoracostomy and then bronchoplasty. Bronchoplasty was performed within 3 days in four patients and on days 16 and 30, respectively, in the other two patients. The affected lung demonstrated full expansion in all patients immediately after bronchoplasty. Follow-up bronchoscopy showed good patency of all bronchi.

Accidents, Traffic↗

PubMed1995

Effects of Maillard reaction products on mutagen formation in boiled pork juice.

The three IQ (2-amino-3-methylimidazo[4,5-f]quinoline) compounds IQ, MeIQx (2-amino-3,4-dimethyl[4,5-f]quinoxaline) and MeIQ (2-amino-3,4-dimethylimidazo[4,5-f]quinoline) have been found in boiled pork juice. To determine which Maillard reaction products are important in the formation of IQ-type mutagens in boiled pork juice, six Maillard reaction products were separately added to the pork juice before reflux boiling and then the mutagenicity of each sample was examined with Salmonella typhimurium TA98 in the presence of S9 mix. The addition of four Maillard reaction products enhanced the mutagenicity of pork juice 1.2-2.9-fold after reflux boiling. The highest level of enhancement was observed with tetrahydrothiophene, followed by 2,3-dimethylpyrazine, 3-methylpyridine and 2-methylpyridine. However, the addition of 2-acetylpyrrole and imidazole greatly inhibited the mutagenicity of pork juice. To confirm which IQ-type mutagens were changed, four major mutagenic fractions were monitored after HPLC separation by their mutagenicity with Salmonella typhimurium TA98. By comparing the retention time of authentic IQ compounds from boiled pork juice with added tetrahydrothiophene or 2,3-dimethylpyrazine, we show that four major HPLC fractions have significantly increased mutagenicity compared with the same fractions in boiled pork juice alone. In contrast, the mutagenicity of these fractions was considerably reduced with the addition of imidazole or 2-acetylpyrrole to the pork juice before refluxing. The residual amounts of tetrahydrothiophene and 2,3-dimethylpyrazine added to the boiled pork juice after heating were measured by gas chromatography and found to be inversely correlated with the mutagenicity of the pork juice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Formation and identification of carcinogenic heterocyclic aromatic amines in boiled pork juice.

Bacterial frameshift mutagens have been found in boiled pork juice. The mutagenic compounds of boiled pork juice were purified and analyzed by HPLC. The mutagenic fractions corresponding to the peaks of the standard mutagens 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) were confirmed by comparison of UV and mass spectra. One gram equivalent of original lean ground pork was estimated to contain 4.1 ng of MeIQx, 3.7 ng of IQ, and 1.2 ng of MeIQ, which accounted for 21.0%, 30.4%, and 38.1%, respectively, of the total mutagenicity. The remaining mutagenic fractions might be diMeIQx isomers. This will be further confirmed by mass spectrometry in future studies. The amount of IQ-type mutagens in boiled pork juice was about 4-fold higher than in broiled beef. Furthermore, we investigated the effects of 20 amino acids, three monosaccharides, and creatinine on mutagen formation when added to the pork juice to elucidate possible precursors leading to the formation of mutagens. Results showed that five amino acids (glutamine, tyrosine, glycine, alanine, and threonine) and two monosaccharides (ribose and glucose) might participate in mutagen formation in boiled pork juice.

Amines↗

PubMed1994

Presence of F-like OriT base-pair sequence on the virulence plasmids of Salmonella serovars Gallinarum, Enteritidis, and Typhimurium, but absent in those of Choleraesuis and Dublin.

The 90 kb virulence plasmids of Salmonella biosers Gallinarum and Pullorum (expressed as serovar Gallinarum) are non-conjugative. They were, however, found to be readily mobilized by IncFI and IncFIV plasmids, but not by conjugative IncA, IncB = C, IncH, IncL and IncM R plasmids. No virulence plasmids of serovars Choleraesuis, Dublin, Enteritidis, and Typhimurium were mobilized by any of these conjugative plasmids. The 90 kb virulence plasmid of Gallinarum was shown to hybridize to the Tra genes region of IncFI and IncFIV plasmids, suggesting it contains some F Tra genes region. It also hybridized with 75% homology to the virulence plasmid of Typhimurium, and, in decreasing order, to those of Dublin, Enteritidis, and Choleraesuis. A probe made of 319 basepairs of the F OriT region hybridized with approximately 45% homology to the virulence plasmid of Gallinarum, 63% to that of Typhimurium and 50% to that of Enteritidis. The probe, however, failed to hybridize to the plasmid DNAs of IncA, IncB = C, IncH, IncL and IncM, and to the virulence plasmids of Choleraesuis and Dublin.

Base Composition↗

PubMed1994

Dopamine D2 autoreceptors in rats are behaviorally functional at 21 but not 10 days of age.

Previous studies used either racemic 3-(3-hydroxyphenyl)-N-n-propylpiperidine [(+/-)-3-PPP] or lower doses of the mixed dopamine (DA) D1/D2 agonist apomorphine (APO) to conclude that brain DA D2 autoreceptors are not behaviorally functional until 28 days of age. The purpose of this study was to provide behavioral evidence for functional D2 autoreceptors before 28 days of age using DA agonists with greater selectivity for D2 autoreceptors. The locomotor activity of 10-, 21-, 35-day-old and adult rats was monitored after injection of a D2 autoreceptor agonist. There were significant decreases in the locomotor activity of 21-, 35-day-old, and adult rats injected with (-)-3-PPP, SND 919, or PD 128483. Lower doses of APO significantly decreased the activity of adult and 35-day-old rats but not younger rats. The only significant effect on the locomotor activity of 10-day-old rats was an increase in activity after injection of APO, 0.01 mg/kg or higher, or B-HT 920, 0.01 mg/kg. The results suggest that brain DA D2 autoreceptors are behaviorally functional at 21, but not 10, days of age.

Aging↗

PubMed1994

Prevention and management of strictures after hypopharyngocolostomy or esophagocolostomy.

The records of 14 patients who underwent surgical revision for anastomotic strictures after hypopharyngocolostomy or esophagocolostomy were reviewed. The esophageal reconstruction was originally performed for esophageal strictures or resections after corrosive injury in 13 patients and for achalasia in 1. The esophageal substitutes used consisted of right ileocolon in 12 patients and left colon in 2. Routes of colon positioning were substernal in 13 patients and subcutaneous in 1. One-half of all strictures were located at the hypopharynx and the other half at the cervical esophagus. Causes of the strictures were anastomotic leakage in 5 patients, progressive caustic scarring in 4, graft ischemia in 3, combined caustic and tuberculous scar in 1, and technical error in 1. The interval from esophageal reconstruction to the revision was 1 month to 15 years with a median of 7 months. Surgical approaches included cervical incision only in 9 patients, cervical incision plus sternotomy in 3, and cervical incision plus partial resection of sternal manubrium in 2. Revisional procedures consisted of excision of scar with reanastomosis in 12 patients, skin graft in 1, and free jejunal graft in 1. After revision, all but 1 patient had excellent results. On the basis of these experiences we conclude that most strictures after pharyngocolostomy or esophagocolostomy can be surgically corrected after excision of the scar and mobilization of the esophageal substitute through a cervical incision only or a cervical incision plus sternotomy.

Adult↗

PubMed1994

The D2 autoreceptor agonists SND 919 and PD 128483 decrease stereotypy in developing rats.

Although stereotyped behavior in adult rats is partly regulated by dopamine (DA) D2 autoreceptors, previous attempts to demonstrate D2 autoreceptor regulation of stereotypy in developing rats have been unsuccessful. In the present study, two highly selective D2 autoreceptor agonists were used to demonstrate D2 autoreceptor regulation of spontaneous stereotyped behavior in developing rats. Both SND 919 and PD 128483 produced significant dose-dependent decreases in the stereotypy counts of 21-day-old, 35-day-old, and adult rats. There was a 51% decrease in the stereotypy counts of 21-day-old rats injected with SND 919, 0.05 mg/kg, compared to a 36% decrease in the counts of rats pretreated with haloperidol. Similarly, PD 128483 significantly decreased the stereotypy counts of 21-, 35-day-old, and adult rats in a dose-dependent fashion. There was a 58% decrease in the stereotypy counts of 21-day-old rats injected with PD 128483, 0.1 mg/kg, compared to a 17% decrease in counts when the rats were first treated with haloperidol. The effect of haloperidol plus PD 128483 was significantly different from the effect of PD 128483 alone. Injection of SND 919 or PD 128483 had no significant effects on the stereotypy counts of 10-day-old rats. The results suggest that DA D2 autoreceptor-mediated regulation of spontaneous stereotyped behavior is functional at 21, but not 10, days of age.

Aging↗

PubMed1994

Presence of hepatitis B surface antigen (HBsAg)-specific cytotoxic T cells in asymptomatic HBsAg carriers.

To investigate whether there is any evidence of an immune stimulation against hepatitis B virus surface antigen (HBsAg) in asymptomatic HBsAg carriers, proliferative and cytotoxic responses to HBsAg were measured in their peripheral blood lymphocytes. Although the majority of asymptomatic carriers had no proliferative response to HBsAg, 3 (25%) of 12 carriers showed significant T cell proliferation against HBsAg. In addition, using HBsAg-expressing autologous lymphoblastoid cell line (LCL) as target cells, HBsAg-specific cytotoxic activity was found in 2 of 3 asymptomatic HBsAg carriers who had a proliferative response against HBsAg. Furthermore, 6 cytotoxic T lymphocyte (CTL) clones were isolated from 1 asymptomatic carrier. The epitope recognized by 2 CTL clones was mapped to the major HBsAg residues 158-172. These CTL clones were able to produce interferon-gamma, tumor necrosis factor-alpha, or granulocyte-macrophage colony-stimulating factor. These findings demonstrate the presence of HBsAg-specific, major histocompatibility complex class I-restricted CTL in asymptomatic HBsAg carriers.

Adult↗

PubMed1994

Characterization of the mutagen 2-amino-3-methylimidazo[4,5-f]quinoline prepared from a 2-methylpyridine/creatinine/acetylformaldehyde model system.

A mixture of 2-methylpyridine, creatinine and aldehydes was heated in diethylene glycol containing 5% water for 1 h at 140 degrees C. The mutagenic compounds were purified by XAD-2 column chromatography, acid/base partition, blue cotton treatment, thin layer chromatography and HPLC. The active substances purified from each step were monitored by their mutagenicity with Salmonella typhimurium TA98 in the presence of S9 mix. Among the mutagens collected, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was isolated from HPLC, and was identified by its UV and mass spectrum using a photodiode array detector and mass spectrometry. Our findings appear to be the first experimental evidence to substantiate the hypothetical pathway for the formation of IQ mutagens from a heated model system consisting of a pyridine or pyrazine derivative, an aldehyde and creatinine or creatine.

Biotransformation↗