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Biomedical subjects

T L Lin

Publications and source records attributed to T L Lin.

At least 73 records · Page 4Linked to original sources
PubMed1993

Thymic atrophy caused by ethanol in a mouse model for binge drinking: involvement of endogenous glucocorticoids.

Consumption of large amounts of ethanol (EtOH) in a single drinking episode is common, but very little is known about the immunological effects of such occurrences. Exposure to EtOH for several days is immunosuppressive in rodent models, and a single dose of EtOH causes substantial increases in endogenous glucocorticoid levels which might have immunosuppressive effects. In the present study, the effects of a single dose of EtOH on the thymus and the role of endogenous glucocorticoids in these effects were examined in B6C3F1 female mice. A single dose of EtOH decreased thymus weight and cellularity, predominantly by elimination of CD4+CD8+ (immature) thymocytes. This occurred over a broad range of EtOH doses and was associated with behavioral effects (ranging from mild ataxia to unresponsiveness) similar to those noted in human binge drinkers. Several lines of evidence indicate that the effects of EtOH on the thymus are mediated by endogenous glucocorticoids: (1) corticosterone levels in EtOH-treated mice increased more than 10-fold and remained significantly elevated for up to 12 hr; (2) the most glucocorticoid-sensitive thymocytes (CD4+CD8+ cells) were preferentially depleted by EtOH; (3) before thymocyte depletion was evident, substantial DNA fragmentation occurred in the thymus as would be expected in the case of glucocorticoid-induced apoptosis; (4) the glucocorticoid antagonist, RU 486, blocked thymic atrophy and DNA fragmentation in EtOH-treated mice; (5) EtOH and its major metabolites at concentrations comparable to or greater than expected in vivo did not decrease thymocyte viability in 20-hr cultures, indicating that direct action of EtOH or its metabolites on thymocytes does not play an important role in EtOH-induced thymic atrophy. These results suggest that a single dose of EtOH induces thymic atrophy which is predominantly mediated by increased levels of endogenous glucocorticoids. The mouse model described here should be useful in evaluating other effects of binge drinking on the immune system, and the experimental strategy described should be applicable in investigating the role of endogenous glucocorticoids in thymic atrophy induced by other chemicals and drugs.

Animals↗
PubMed1993

Low-substituted hydroxypropylcellulose as a sustained-drug release matrix base or disintegrant depending on its particle size and loading in formulation.

Tablets of acetaminophen as a model drug were prepared with low-substituted hydroxypropylcellulose (L-HPC) of various particle sizes at various loadings in the formulation. Drug release into an aqueous dissolution medium (pH 1.2) was remarkably sustained from tablets prepared with fine L-HPC (LH41) at loadings of more than 20%. Tablets prepared with less than 20% LH41 or with coarse L-HPCs (LH11, LH21, and LH31) disintegrated in the medium, resulting in rapid release of the drug. The difference in behavior could not be explained in terms of differences in tablet strength, but in swelling and water uptake abilities of the tablet's polymer. Swelling work (swelling force), water penetration speed, and water uptake of LH41 (4.4-microns average particle size) were much smaller than those of coarse L-HPCs. The formation of a continuous gel-like layer on the surface of tablets containing more than 20% LH41 was another factor to sustain the drug release rate.

Acetaminophen↗
PubMed1993

Chemiluminescent detection of infectious bursal disease virus with a PCR-generated nonradiolabeled probe.

A polymerase chain reaction (PCR)-generated digoxigenin-labeled nonradioactive oligonucleotide probe was developed and utilized in slot-blot hybridization coupled with chemiluminescence for the detection of infectious bursal disease virus (IBDV). The probe was prepared from the RNA of the standard challenge strain (STC) of IBDV serotype 1 by reverse transcription followed by 2 PCR amplifications with 2 separate sets of primers. RNA of STC viruses prepared from bursae infected with STC viruses was subjected to the first PCR with the outer primers V8 and V9 that amplified a 607-base pair (bp) segment. The PCR product from the first PCR was eluted following agarose gel electrophoresis and subjected to the second PCR with the nested primers V6 and V7 that flanked a 351-bp segment. In the second PCR, dTTP was substituted by digoxigenin-11-dUTP in the PCR reaction mixture so that the amplified 351-bp DNA products were labeled with digoxigenin. The specificity of the PCR-generated digoxigenin-labeled probe was tested on different strains of IBDV, several unrelated avian viruses, and bacteria by slot-blot hybridization assay. Hybridization was detected by chemiluminescence. The sensitivity of the probe was assayed using 10-fold serial dilutions of purified RNA from the STC strain of IBDV. The PCR-generated digoxigenin-labeled probe hybridized with genomic RNA of STC and variant strains A, D, E, G, and GLS-5 of IBDV serotype 1 but not OH strain of IBDV serotype 2. The probe did not react with avian reovirus, infectious bronchitis virus, Salmonella enteritidis, Escherichia coli, or Staphylococcus aureus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Nandrolone decanoate reduces the premature mortality of cardiomyopathic hamsters.

Male hamsters of an inbred strain carrying a genetic trait for cardiomyopathy were dosed by sc injection weekly with an anabolic-androgenic steroid, nandrolone decanoate, beginning when 3 months old. Two groups (N = 17) received doses of 2 and 4 mg per animal, while a vehicle control group received an equal volume of sesame oil. Rather than a hypothesized shortening of longevity, the steroid treatment significantly prolonged survival of the hamsters, which ordinarily die of congestive heart failure. At the median time to death for controls (355 days of age, 257 days of treatment), the steroid groups had mortality of only 2/17 and 4/17 (vs. 9/17, p < 0.01).

Anabolic Agents↗
PubMed1992

Effect of macrophage activation on killing of Listeria monocytogenes. Roles of reactive oxygen or nitrogen intermediates, rate of phagocytosis, and retention of bacteria in endosomes.

The role of macrophage activation in the killing of L. monocytogenes is unclear. Some studies suggest that activation for enhanced production of reactive oxygen and nitrogen intermediates may not be of central importance. Recent data have indicated an important role for interferon-gamma (IFN-gamma) induced retention of L. monocytogenes in endosomes. Data from the present study indicate that proteose peptone-elicited macrophages from DBA2/J, CD-1, and C3H/HeN mice are listericidal. Activation of these cells in vitro for 20 h by IFN-gamma (20 or 500 U/ml) increased H2O2 or nitrite production, but did not increase the number of L. monocytogenes killed during a subsequent 6-h or 7-h culture. Incubation of macrophages with IFN-gamma plus lipopolysaccharide (LPS) caused greater activation and increased the number of Listeria killed during a 6-h or 7-h culture. However, this seems primarily attributable to enhanced phagocytosis. Proteose peptone-elicited macrophages were significantly more effective than resident macrophages in preventing the escape of L. monocytogenes from endosomes into the cytoplasm. This capability was not significantly enhanced by IFN-gamma in vitro, but was enhanced by IFN-gamma plus LPS. This correlates well with the effects of these activation stimuli on killing of L. monocytogenes by proteose peptone-elicited macrophages. These results indicate that enhanced retention of L. monocytogenes in endosomes is induced by proteose peptone elicitation and that further macrophage activation in vitro by IFN-gamma does not improve listericidal activity.

Analysis of Variance↗
PubMed1989

Triploidy (117,XXX) in a stillborn canine pup conceived with frozen semen.

Analysis of skin fibroblast cultures from a deformed stillborn female Alaskan Malamute pup revealed a 3n = 117,XXX (normal, 2n = 78,XX) chromosome count. The triploid pup was delivered by cesarean section 5 days after estimated date of parturition, because the bitch failed to start labor. The bitch had been inseminated with thawed frozen semen deposited into the lumen of the uterus approximately 4 days after ovulation. Gross anatomic abnormalities of the pup included omphalocele, diaphragmatic hernia, persistent right aortic arch, atresia ani, and no right forelimb distal to the scapula. The pup also had arthrogryposis of the left carpus, kyphosis of the thoracic vertebrae, widely separated cranial sutures, open fontanelles, hydrocephalus, and cleft palate. Suspected cause of the triploidy was dispermy of an aged oocyte after intrauterine deposition of the thawed frozen semen. Numeric chromosome abnormalities may be causes of fetal deformity or death that can be detected by fetal karyotype.

Animals↗
PubMed1989

Unique changes found on the Qi Gong (Chi Gong) Master's and patient's body during Qi Gong treatment; their relationships to certain meridians & acupuncture points and the re-creation of therapeutic Qi Gong states by children & adults.

Changes taking place in both Qi Gong Masters and their patients during Qi Gong treatment were evaluated using the Bi-Digital O-Ring Test. During the Qi Gong state, on the Qi-Gong Master's body, as well as the body of the patient being treated, acupuncture points CV5 (Shi Men) and CV6 (Qi Hai)-- located below the umbilicus-- show changes from +4 in the pre-Qi Gong state to between -3 and -4 during the Qi Gong state. Before and after the Qi Gong, there is a normal +4 response to the Bi-Digital O-Ring Test at these acupuncture points. Similar changes were also observed on acupuncture points CV17 (Shan Zhong), CV 22 (Tian Tu), Yin Tang (at an area just between the eyebrows: the pituitary gland representation area, colloquially known as the "third eye") and GV20(Bai Hui), the entire pericardium meridian & triple burner meridian, their acupuncture points, the adrenal glands, testes, ovaries and perineum, as well as along the entire spinal vertebrae, particularly on and above the 12th thoracic vertebra, medulla oblongata, pons, and the intestinal representation areas of the brain located just above and behind the upper ear. Using these findings as criteria for evaluating the effectiveness of reaching the Qi Gong state, we were able to reproduce during the experimental trials similar changes in ourselves and the patient being treated with therapeutic effects comparable to those of the Qi Gong Master. Beneficial effects of external Qi Gong treatment given by a Qi Gong practitioner 1 to 3 times for 10-20 seconds each (although most Qi Gong masters take 3-20 minutes per treatment) often resulted in improvement of circulation and lowering of high blood pressure, as well as relaxation of spastic muscles, relief of pain, and enhanced general well-being, all of which resemble acupuncture effects. In order to reproduce the same procedure with others, we selected 4 children ranging between 8 and 11 years of age who had no knowledge of Qi Gong or Oriental medicine. One of these four children, the 8 year old, was able to consistently reach the same Qi Gong state after less than a half day and another child, 11, after less than 2 days. Within a week, the other two were sometimes able to reproduce the Qi Gong state but not always. Using the Qi Gong state thus obtained, it was found that this type of Qi Gong energy is directed to specific directions from the hand and can even penetrate wooden or metal doors.(ABSTRACT TRUNCATED AT 400 WORDS)

Acupuncture Therapy↗
PubMed1989

[Experience in using modified HM-3 Dornier lithotripter to treat urinary tract stones].

Low pressure generator has been developed mainly to reduce pain and kidney injury while at the same time maintain an equally effective stone-free rate. Our experience in using Modified HM-3 Dornier lithotripter to treat urinary tract stones has given an average of stone-free rate (58.88%) quite similar to what the conventional one can give. Compared with the conventional intervention, the modified one might increase by 52.07% (2281 vs 1500 pulses) in the average frequency of shock wave and by 26.52% (38.40 vs 30.35 minutes) in average operation time. However, low pressure may contribute to less complications and overall smoother procedure under oral analgesic use.

Adolescent↗
PubMed1989

[Use of double-J in extracorporeal shock wave lithotripsy of large renal calculi].

Treatment of large renal calculi by extracorporeal shock wave lithotripsy alone has not been accepted yet as the treatment of choice because of the high incidence of complications such as stone street inducing obstructive uropathy. From Sep. 1987 to Nov. 1987, Thirty four patients had received double-J catheter in ureter before E.S.W.L. to prevent ureteral obstruction. The age distribution was from 29 to 66 years old (mean = 49.1 Y/O) and male to female ratio was 3:1. All the stone size was larger than 20mm in its longest axial length. Each patient was followed at least 3 months, and the results indicated that 8 patients (23.53%) had stone free, 11 patients (32.35%) had sandy stone in kidney, and 15 patients (44.12%) had stone street in ureter. The additional treatments for significant residual stone included 3 patients needing ureteroscopy, 8 patients needing more than one session of E.S.W.L. and 4 patients having spontaneous stone passage after removal of double-J. Although the necessity of external diversion and the incidence of colic pain after E.S.W.L. would reduce so as to improve patients' quality of life, double-J does not increase the stone free rate, and ureteral obstruction was still possible to induce the renal function impairment. We suggest that double-J be removed as soon as possible if the stone fragments have no change in position after 2-4 weeks of followup and adjuvant treatment be necessary.

Adult↗
PubMed1985

Carotenoids and vitamin A: the effect of hypocholesterolemic agents on serum levels.

Serum total carotenoid (STC) and vitamin A levels were done as part of the biochemical screening in comparative studies of lipid lowering agents in type Ila hyperlipoproteinemic patients. STC levels were reduced following bile acid sequestering agent administration (colestipol 30 g/d) by 30% (P less than 0.01). Clofibrate and avicel placebo had inconsistent and nonsignificant effects on the STC levels. Serum vitamin A levels were not significantly altered by any of the test agents. The STC level changes were not correlated with concomitant changes in low-density lipoprotein-cholesterol (LDL-C) during any of the treatment regimens. It is suggested that STC level changes are related to alterations in the absorption of carotenoids during bile acid sequestrant administration.

Adult↗