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Biomedical subjects

M T Lin

Publications and source records attributed to M T Lin.

At least 181 records · Page 10Linked to original sources
PubMed1994

Severe isolated acute hepatic graft-versus-host disease with vanishing bile duct syndrome.

A 28-year-old man with chronic myelogenous leukaemia in blastic transformation underwent allogeneic bone marrow transplantation from his HLA-identical brother. Severe, progressive cholestatic jaundice developed from day 25 and did not respond to repeated therapy with high-dose methylprednisolone. In addition to marked cholestasis, both liver biopsy (day 69) and autopsy (day 134) findings revealed total disappearance of interlobular bile ducts in all of the portal areas, although extrahepatic manifestations of GVHD were minimal. Isolated acute vanishing bile duct syndrome can occur as the most severe form of acute hepatic GVHD.

Acute Disease↗
PubMed1993

Establishment and characterization of an HTLV-I cell line from a Taiwanese patient with HTLV-I-associated myelopathy.

We describe a Taiwanese woman with chronic progressive myelopathy, in whom Western blot analysis of the serum and cerebrospinal fluid (CSF) displayed positive reactions to human T-lymphotropic virus type I (HTLV-I) proteins, p19, p24, p28, p36, gp46 and p53. HTLV-I proviral genomes were detected in the peripheral blood mononuclear cells (PBMC) and CSF cells by nested polymerase chain reaction and Southern blot hybridization. HTLV-I was successfully isolated from PBMC stimulated with interleukin-2 (IL-2). The established cell line, named THAM-1, was an IL-2-independent T-cell line with CD2+, CD3+, CD4+, CD25+ and HLA-DR+. Retrovirus particles with type C morphology were observed in the THAM-1 cells by electron microscopy, and HTLV-I-related antigens were also demonstrated by immunocytochemical staining and Western blot assay. Southern blot analysis revealed that HTLV-I proviral genomes were integrated into the THAM-1 cellular DNA. In Northern blot analysis, two extra-species of RNA were detected in addition to three typical viral transcripts. For the first time, an HTLV-I-producing T cell line was established from a patient with HTLV-I-associated myelopathy in Taiwan, an HTLV-I non-endemic area.

Adult↗
PubMed1993

Epstein-Barr virus-containing T-cell lymphoma presents with hemophagocytic syndrome mimicking malignant histiocytosis.

BACKGROUND: The previously designated malignant histiocytosis (MH) may include lymphoid neoplasms of T-cell lineage as well as patients with benign virus-associated hemophagocytic syndrome (VAHS). In this study, the association of Epstein-Barr virus (EBV) with T cell lymphomas which present with clinicopathologic features indistinguishable from malignant histiocytosis (MH) was investigated further. METHODS: Four adult patients, three women and one man, were admitted because of fever, cutaneous lesions, hepatosplenomegaly, and jaundice. Laboratory examinations revealed pancytopenia, abnormal liver functions and coagulopathy. All patients ran a fulminant course terminating in a hemophagocytic syndrome within 1 month. Immunophenotypic study, Southern blot analysis, and in situ hybridization were performed on the specimens obtained from the four patients. RESULTS: The biopsy-necropsy specimens from skin, liver, spleen, and bone marrow showed infiltration of atypical large cells with reactive histiocytosis and florid hemophagocytosis activity. Based on the clinical and histologic findings, these cases would have been designated as MH by previous criteria. Immunophenotypic, Southern blot, and in situ hybridization studies, however, showed clonotypic proliferation of EBV genomes in the nuclei of the large atypical cells that expressed T-cell antigens. Therefore, these patients should be diagnosed as a recently described EBV-associated peripheral T-cell lymphoma (EBV-PTCL). CONCLUSIONS: EBV-PTCL may present with a fulminant hemophagocytic syndrome indistinguishable from the previously designated MH. This finding represents a step forward in our changing concept regarding MH, some of which only recently has been suggested to be of T-cell lymphoma origin. Differentiation from benign VAHS is clinically important. Features useful in this distinction are tabulated and discussed.

Adult↗
PubMed1993

The interaction between locomotion, striatal dopamine and paramedian reticular nucleus in rats.

Either intact rats, sham-operated rats, or rats with lesions of the paramedian reticular nucleus (PRN) were exposed to cold (2 degrees C) or heat (36 degrees C) stress and their locomotor activity responses and striatal dopamine (DA) release were compared. At room temperature (22 degrees C), results analyzed revealed significant effects in the PRN-lesioned rats: increases in locomotion (including both horizontal and vertical motion), direction of turnings (including both clockwise and anticlockwise) or striatal DA release. In both the intact rats and the sham-operated rats, either cold or heat stress increased the locomotion, the direction of turnings and the striatal DA release. The increases in both vertical motion and striatal DA release following cold or heat stress were attenuated by PRN lesions. The data suggest that a PRN-striatal DA link existing in rat's brain which affects both the spontaneous and the thermal stress induced locomotor activities.

Animals↗
PubMed1993

Arterial baroreceptor information affects striatal dopamine release measured by voltammetry in rats.

The effects of altering the arterial blood pressure on the extracellular levels of dopamine in the corpus striatum, measured using nafion-coated C fiber electrodes combined with differential pulse amperometry, were assessed in urethane-anesthetized rats. The striatal dopamine release was increased by increasing the carotid blood pressure with phenylephrine injection but decreased by decreasing the carotid blood pressure with bilateral carotid occlusion. The data indicate that baroreceptors inputs affect the striatal dopamine release in rats.

Animals↗
PubMed1993

Cloning and expression of the gene encoding Acacia confusa trypsin inhibitor that is active without post-translational proteolysis.

A recombinant plasmid containing the coding regions for Acacia confusa trypsin inhibitor (ACTI) has been constructed and expressed in Escherichia coli cells, as a fusion protein between ACTI and glutathione S-transferase (GST). The GST-fusion was produced as a soluble protein which did not require denaturing agents such as urea to solubilize it. The recombinant ACTI (reACTI) was obtained by treating the GST-fusion protein with thrombin. Both the reACTI and fusion protein have a strong inhibitory effect on trypsin activity without post-translational proteolysis.

Acacia↗
PubMed1993

The effect of copper ion on arachidonic acid metabolism in the porcine corneal epithelium.

The effect of copper ion on arachidonic acid metabolism in the corneal epithelium was studied. Our results showed that when 3H-arachidonic acid (1 microCi/microgram) was incubated with homogenate of corneal epithelium at 37 degrees C for 45 min., three metabolites were formed. Metabolite A, the major metabolite, was identified as 12-HETE by HPLC and GC. An analysis with chiral phase HPLC revealed that metabolite A was a (R)-enantiomer. The production of 12(R)-HETE was stimulated by low concentrations of CuCl2 (< 0.1 mM) and inhibited by higher concentrations of CuCl2. Study on the biological activity of 12(R)-HETE showed that it could stimulate migration of endothelial cells in a concentration as low as 10 ng/ml. These results suggest that one of the effects of copper ion on the corneal neovascularization may be to regulate the level of 12(R)-HETE.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1993

Endogenous pyrogen formation by human blood monocytes stimulated by polyriboinosinic acid:polyribocytidylic acid.

The pyrogenic response to supernatants from human blood monocytes stimulated with polyriboinosinic acid:polyribocytidylic acid (poly I:C) was characteristic of a response to endogenous pyrogen in that it was brief and monophasic, and was destroyed by heating the supernatants at 70 degrees C for 30 min. Pyrogen production was unimpaired when the incubations were carried out in the presence of cycloheximide (50 micrograms/ml; an inhibitor of protein synthesis) or indomethacin (50 micrograms/ml; an inhibitor of prostaglandin synthesis). Also, neither interferon, interleukins, tumor necrosis factor nor prostaglandin E2 were detectable in the supernatants from the poly I:C-stimulated human monocytes.

Animals↗
PubMed1993

Antagonistic effects of stimulation of the paramedian reticular nucleus in the rat medulla oblongata and of amphetamine on locomotor activity and striatal release of dopamine-like material.

The effects of stimulation of the paramedian reticular nucleus (PRN) in the rat medulla oblongata on both amphetamine-induced locomotor activity and striatal release of dopamine-like material were assessed. PRN stimulation (by intra-PRN injection of the excitatory amino acid, kainic acid) decreased vertical motion and total distance travelled, and increased postural freezing, in freely moving rats. On the other hand, a small dose (e.g. 1.25 mg/kg, i.p.) of amphetamine increased locomotor activity (including horizontal motion, vertical motion, total distance travelled and lines crossed counts), increased the number of turnings (both clockwise and anti-clockwise), induced locomotor stereotypy (including both gamma value and number of trip types), and inhibited postural freezing. The changes in activity induced by amphetamine administration were suppressed following PRN stimulation. In vivo voltammetric data revealed that electrical stimulation of the PRN decreased the release of dopamine-like material in the corpus striatum. This effect could be mimicked by intra-PRN injection of kainic acid in anesthetized rats. In contrast, i.p. administration of amphetamine increased the release of dopamine-like material in the corpus striatum. Furthermore, the enhanced release of dopamine-like material induced by amphetamine was attenuated by simultaneous stimulation of the PRN. The results reported here indicate that PRN stimulation decreases the striatal dopamine release and results in attenuation of the amphetamine-induced locomotor activity responses in rats.

Amphetamine↗
PubMed1993

A modularized infrared light matrix system with high resolution for measuring animal behaviors.

The current study provides a new modularized infrared light matrix system (about $200 cost) which is designed to measure the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, freezing time, and total distance traveled in rats. The system records the sequences of animal's activity in a computer-aided system with a resolution of 0.2 s in time or 1.6 cm in space, and permanently stores all the resulting data in file. The behavioral apparatus was tested for its sensitivity and usability by amphetamine-injected rats. It was found that intraperitoneal administration of amphetamine (1.25-2.50 mg/kg), but not normal saline, produced a dose-related increase in either the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, or total distance traveled. However, amphetamine injections produced a dose-related decrease in freezing time. Apparently, most of the amphetamine-induced responses obtained by other detecting apparatus can be reproduced easily by the present apparatus. The current detection system possesses the following advantages: a) high resolution, b) high expansion potential, and c) precise and simplified algorithms for behavioral parameter analysis.

Algorithms↗
PubMed1993

Lymphoblast colony-culture assay in acute lymphoblastic leukemia: a quantitative approach.

Lymphoblast colony-culture of adult acute lymphoblastic leukemia (ALL) was studied to explore its clinical implication. Among 13 marrow cultures from ALL patients with full-blown disease, 11 developed leukemic colonies. A type of colony, very similar to a lymphoblastic colony and possibly T-cell in origin, could be found in four cultures of the six control marrows. To minimize the difficulty in differentiating a leukemic blast colony and a normal lymphocyte colony, based solely on morphology, a quantitative approach was used. Since both the mean of blast colony count and the mean of blast percentage of leukemic marrow were significantly higher than those of the control group, mean value plus two standard deviations of the control group were defined arbitrarily as upper normal limits. The defined normal range was then used to examine the relationship between results of the cultures and clinical outcome for the ALL patients. Early relapse or incomplete remission following chemotherapy could be predicted in four patients by these quantitative colony-culture assays 0.5-2 months before full-blown disease. The low colony count and low blast percentage in the colony-culture assay of the fifth patient is compatible with the clinical observation of continuous remission. One culture, growing clusters only, had an increased blast percentage; this correlated well with cytogenetic relapse two months later. In summary, the quantitative colony-culture assay could detect morphologically unidentifiable leukemic cells in ALL patients with early relapse or incomplete remission. This quantitative colony-culture system, though not ultrasensitive in the detection of minimal residual leukemic cells, was of potential value as a prognostic assay.

Adolescent↗
PubMed1993

A simplified method for selecting a carbon-fiber electrode in pulse voltammetry.

A method for selecting a usable carbon-fiber electrode using the equivalent resistance and capacitance is presented. This method uses an instrument with a PC-based look-up table for measuring the electrical characteristics of a carbon-fiber electrode in pulse voltammetry. Using this instrument, the equivalent resistance and capacitance of the carbon-fiber electrode in saturated sodium chloride solution can be obtained. This instrument includes a decade resistance box, a peak current detection and hold circuit, a half peak comparator and a decay duration counter. A look-up table is established by using RC circuits to emulate the electrochemical reaction of the carbon-fiber electrode in pulse voltammetry. The equivalent resistance is obtained from the decade resistance box according to Kirchhoff's law. Then the equivalent capacitance is determined from the decay duration counter reading and equivalent resistance with the look-up table via a PC interpolation program. After obtaining the equivalent resistance and capacitance of an electrode, the values are compared with the usable thresholds. This method provides an effective quality evaluation index of carbon-fiber electrode for the user in order to reduce electrode-induced experimental failure. The method is also available for other kinds of carbon-fiber electrodes as long as their look-up table and desired thresholds are established.

Electric Conductivity↗
PubMed1993

Antagonistic effects of lesions of paramedian reticular nucleus on amphetamine-induced locomotion and striatal dopamine release in rats.

Systemic administration of amphetamine (1.25 mg/kg) produced increases of locomotion (including horizontal motion, vertical motion, and total distance travelled), elevations of turnings (including both clockwise and anticlockwise) and inhibition of postural freezing in freely moving rats. All the afore-mentioned activity measures induced by amphetamine were suppressed following electrolytic lesions of the paramedian reticular nucleus (PRN) in rat medulla. In addition, the spontaneous level of either the locomotor activity, the direction of turnings, or the postural freezing were slightly but significantly affected by the PRN lesions. In vivo voltammetric data revealed that amphetamine administration greatly enhanced the striatal dopamine release. Furthermore, the enhanced dopamine release in corpus striatum produced by amphetamine were greatly attenuated by PRN lesions. The results indicate that there exists a PRN-striatal dopamine link in rat brain which mediates the amphetamine-induced increases of locomotion and turnings, as well as decreases of postural freezing.

Amphetamines↗
PubMed1993

Human plasmin induces a receptor-mediated arachidonate release coupled with G proteins in endothelial cells.

Treatment of cultured bovine carotid artery endothelial cells with 10(-7) M plasmin increased arachidonate release coupled with the increase in prostacyclin production. The stimulatory effect of plasmin on arachidonate release could be divided into the early and late phases according to its calcium dependency and pertussis toxin sensitivity. The early phase of plasmin-induced arachidonate release was a calcium-dependent and pertussis toxin-sensitive response, which was observed within 20 min after plasmin treatment. The late phase was a calcium-independent and pertussis toxin-insensitive response, which was induced gradually from 20 to 60 min. Induction of the early phase of plasmin's effect required both the lysine binding and catalytic sites in plasmin molecule because it was inhibited either by the binding antagonist tranexamic acid or by the serine protease inhibitor aprotinin. Guanosine 5'-O-(2-thiotriphosphate) potentiated the effect of plasmin in permeabilized or nonpermeabilized cells, indicating that the early phase effect was mediated by a pertussis toxin-sensitive guanosine 5'-triphosphate (GTP)-binding protein. The late phase of plasmin's effect was due to the catalytic activity because it was inhibited by aprotinin but not by tranexamic acid. Microplasmin structurally having the catalytic sites induced a similar late phase effect. Plasmin did not elicit the metabolism of phosphatidyl polyphosphoinositides. These studies demonstrate that the activation of phospholipase A2, which results in arachidonate release, in the early phase of plasmin's effect is a receptor-mediation via GTP-binding protein that is not coupled through phospholipase C activation.

Animals↗
PubMed1993

Alpha-methyl-p-tyrosine reduces poly I:C-induced augmenting interferon production and splenic natural killer cell activity in mice.

The present investigation was designed to extend our previous observations that alpha-methyl-p-tyrosine (AMPT; an inhibitor of norepinephrine synthesis) reduced splenic natural killer (NK) cell activity and to test whether NK augmentation or augmenting interferon (IFN) production induced by polyriboinosinic acid:polyribocytidylic acid (poly I:C; an IFN inducer) can be attenuated by AMPT in mice. Therefore, in the current study, the effects of AMPT (300 mg/kg i.p.) on splenic NK activity or plasma titers of IFN-alpha+beta were assessed in inbred C57BL/6 mice. It was found that treatment with AMPT reduced both poly I:C induced serum IFN and splenic NK activity in a dose- and time-dependent manner. These results suggest that AMPT inhibits IFN production and decreases splenic NK activity in vivo.

Animals↗
PubMed1993

Melatonin decreases brain serotonin release, arterial pressure and heart rate in rats.

The effects of intravenous administration of melatonin (30-60 mg/kg) or vehicle (10% alcohol) on arterial pressure, heart rate, blood gases or brain serotonin release were assessed in rats under urethane anesthesia. Administration of melatonin, but not the vehicle, produced a dose-related fall in mean arterial pressure, heart rate, or serotonin release in both the corpus striatum and the hypothalamus. Melatonin treatment had an insignificant effect on either PaCO2, PaO2 or pH. In addition, the melatonin-induced depressor responses were abolished by pretreatment with spinal transection, whereas melatonin-induced bradycardia was abolished by pretreatment with bilateral vagotomy. These results suggest that melatonin decreases brain serotonin release and results in sympathetic inhibition or parasympathetic stimulation which leads to hypotension and bradycardia in rats.

Animals↗
PubMed1993

Alterations of cardiovascular functional parameters after onset of heat stroke in rats.

The effects of heat stroke formation on electrocardiogram (ECG) and blood pressure (BP) waveform parameters were assessed in rats under urethane anesthesia. Heat stroke was induced by exposing anesthetized rats to an environmental temperature of 42 degrees C. The movement in which arterial pressure began to decrease was taken as the onset of heat stroke. It was found that the duration of either P were, Q wave, R wave, S wave, T wave or QRS complex, as well as the amplitude of either P wave, Q wave, S wave or T wave were not affected after onset of heat stroke. However, the amplitude of R wave, the P-P interval, the R-R interval and the Q-T interval were significantly decreased after onset of heat stroke. In addition, the peak amplitude of systolic wave, dicrotic notch, diastolic wave, the duration of either systolic wave, a whole BP cycle, diastolic wave or dicrotic wave, the pulse pressure, as well as the mean arterial pressure were also decreased after onset of heat stroke. On the other hand, heat stroke formation increased the heart rate. The results demonstrated that alterations of these ECG and BP waveform parameters occurred after onset of heat stroke in rats.

Anesthesia↗