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Biomedical subjects

S Y Lu

Publications and source records attributed to S Y Lu.

At least 37 records · Page 2Linked to original sources
PubMed1998

Protective properties of tin- and manganese-centered porphyrins against hydrogen peroxide-mediated injury in rat astroglial cells.

Tin-mesoporphyrin (tin-mp), a potent inhibitor of heme oxygenase, and manganese (III) tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), a potent superoxide dismutase mimetic, reduced H2O2 toxicity in cultures of transformed rat astroglial cells if added 30 min before, or at the same time as, H2O2. Reduced toxicity was not observed if treatment was delayed for 60 min, the time by which H2O2 was essentially eliminated from cultures. Coadministration of tin-mp and MnTMPyP did not increase protection over either compound administered individually. Tin-mp, but not MnTMPyP, was stable in culture. MnCl2 was not protective, suggesting that protection by MnTMPyP was not dependent on manganous ion, a by-product of MnTMPyP breakdown. Protection by tin-mp and MnTMPyP was not associated with metalloporphyrin-mediated induction of heme oxygenase-1 or with changes in heme oxygenase-2 on western blots. Whereas protective concentrations of tin-mp did not have superoxide dismutase-mimetic properties in vitro, protective concentrations of MnTMPyP partially inhibited heme oxygenase. The data support the hypothesis that heme oxygenase inhibition is protective against acute oxidative injury.

Animals↗
PubMed1997

[Effect of position change on the PaO2 in patients with unilateral tuberculous pleural effusion].

The effect of body position (right and left lateral position respectively) on gas exchange was observed systematically in 15 patients with unilateral tuberculous pleural effusion. The arterial blood samples were obtained then PaO2 were measured, while the patient lay in the lateral position with normal side down (PaO2-N) for 15 min and with effusion side down (PaO2-E) for 15 min, respectively. The result showed the mean of PaO2-N is significantly higher than that of PaO2-E (P < 0.05). It was postulated that change of PaO2 related to body positions may be attributed to difference in V/Q ratio. Our results may help nurses in managing such patients.

Adult↗
PubMed1996

Localization of heme oxygenase in rat retina: effect of light adaptation.

Heme oxygenase-2 isozyme is the predominant form of heme oxygenase in rat brain by western blot analysis. Heme oxygenase-1 isozyme is not induced by light adaptation in rat retina by western blot analysis. Immunocytochemistry localizes heme oxygenase-2 in three areas of the retina: the retinal pigment epithelium, inner segment and external nuclear layers of the rat retina. Ganglion cells and cell bodies of the internal nuclear layer of the retina and Müller cells were largely unstained for heme oxygenase-2. The localization of heme oxygenase-2 in the retina implies that its function is not associated with phototransduction. Also, light adaptation does not appear to induce heme oxygenase-1, a measure of oxidative injury.

Animals↗
PubMed1996

Transient induction of heme oxygenase after cortical stab wound injury.

Heme oxygenase (HO) exists as two isoenzymes designated heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2). HO-1 has been identified as a heat shock or stress protein and is inducible whereas HO-2 is largely refractory to induction. HO-2 is the predominant isoenzyme in normal brain and appears to have a predominantly neuronal distribution in cerebral cortex. Cortical stab wound injury resulted in HO-1 induction as determined by Western blot analysis. Immunohistochemical analysis suggested that induced HO-1 was largely restricted to reactive astrocytes and macrophage-like cells. Enhanced HO-1 immunoreactivity was observed in hypertrophied, GFAP+ reactive astrocytes near the wound margin as early as 12 h after injury. Very rarely were HO-1+ neurons observed and then only up to 6 h after stabbing. Maximal numbers of HO-1+ astrocytes were found 3 days after stabbing. Their numbers declined thereafter. By 5 days after stab injury few HO-1+ reactive astrocytes were observed although GFAP+ reactive astrocytes were still prominent near the wound margin. HO-1+ macrophage-like cells were initially observed between 1 and 3 days after injury and they persisted in the margin of the wound for at least 14 days. The proximity of HO-1+ cells to the wound margin suggests that factors associated with injury contribute to the regulation of HO-1 in injured cortex.

Animals↗
PubMed1996

Oral tuberculosis.

Tuberculous lesions of the oral cavity have become so infrequent that it is virtually a forgotten disease entity and may pose a diagnostic problem. Fifteen patients with conditions that were histologically diagnosed as oral tuberculosis were reviewed. All were men ranging in age from 29 to 78 years. The most common clinical presentation was odynophagia with a duration from less than 1 week to several years. The most frequently affected sites were the tongue base and gingiva. The oral lesions took the form of an irregular ulceration or a discrete granular mass. Mandibular bone destruction was evident in two patients. Two patients had a fever, and four had cervical lymphadenopathy. Eight cases were clinically suspicious for malignancy before biopsy. Only four patients had a history of tuberculosis, but 14 of the 15 patients were later found to have active pulmonary tuberculosis. Acid-fast bacilli were demonstrated in all patients. Tuberculosis should be considered in patients with an inflamed ulcer lesion. A biopsy specimen for histologic study, acid-fast stains, and cultures should be obtained for confirmation and differential diagnosis with other conditions. If a tuberculous lesion is suspected, a chest radiograph is indicated to investigate the possibility of pulmonary involvement.

Adult↗
PubMed1996

Accumulation of Ga-67 citrate in a tuberculous splenic abscess. Report of a rare case.

A case of 65-year-old man with tuberculous splenic abscess is presented. The Ga-67 citrate scan revealed three focal areas of increased uptake in the left upper quadrant of the abdomen. The combined Tc-99m SC/Ga-67 scans revealed that these Ga-67 avid lesions localized in the splenic photon-deficit areas found in the Tc-99m SC scan. This case demonstrated the usefulness of Ga-67 imaging in a survey of fever of unknown origin in unsuspected tuberculous splenic abscess.

Abscess↗
PubMed1996

[Effect of oxygen therapy on the postoperative patient under general anesthesia].

Adequate oxygen administration has shown a definite benefit for preventing postoperative patients from hypoxia after weaning. Nosal cannula of 3L/min flow rate may maintain a satisfactory blood gas result. For its easy and effective. It should be recommended as a routine intervention of postoperative oxygen therapy especially for those patient whose respiratory function were normal before surgery.

Anesthesia, General↗
PubMed1995

Differential localization of heme oxygenase and NADPH-diaphorase in spinal cord neurons.

Western blot analysis using several antibodies showed that rat spinal cord contained abundant immunostainable heme oxygenase-2 (HO-2) and barely detectable levels of heme oxygenase-1 (HO-1). Anti-HO-2 antibody stained large anterior horn motoneurones and numerous smaller neurons throughout spinal cord gray matter including the dorsal root entry zone. HO-2+ astrocytes were not evident in gray matter although their presence cannot be ruled out. The distribution of HO-2+ neurons was compared with the distribution of cells containing NADPH-diaphorase (NADPH-d) activity, a marker for nitric oxide synthase. NADPH-d activity was restricted to far fewer neurons, many of which were close to the central canal and dorsal root entry zone.

Animals↗
PubMed1995

Differential expression of heme oxygenase-1 in cultured cortical neurons and astrocytes determined by the aid of a new heme oxygenase antibody. Response to oxidative stress.

Heme oxygenase exists as two isoenzymes designated heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2). HO-2 is made constitutively in many cell types whereas HO-1 is a stress protein inducible by heat, heavy metals, ultraviolet irradiation, and oxidative stress. Recombinant rat HO-1 was expressed in bacteria and antiserum designated HO-1713 was raised against the purified protein. HO-1713 detected recombinant rat HO-1 and recombinant rat HO-2. In rat tissues it detected HO-1 and a second, unidentified band designated HO-L (heme oxygenase-like immunoreactivity) which was not HO-2. Cultured rat cortical neurons and forebrain astrocytes were exposed to hydrogen peroxide (0.14-0.7 micromolar for 30 or 60 min). Neurons which contained little detectable HO-1 and which were sensitive to hydrogen peroxide at the high end of the dose curve failed to induce HO-1 by Western blot analysis. In contrast, cultured rat forebrain astrocytes which contained HO-1 under normal culture conditions and which were resistant to injury by hydrogen peroxide, increased their content of immunoreactive HO-1 by 7-fold within 3 h after exposure. Our results support a protective role for HO-1 in oxidative injury and suggest that the relative inability of neurons to increase HO-1 after oxidative stress may contribute to their selective vulnerability vis-a-vis astrocytes. They also suggest that differential expression of heme oxygenase in studies utilizing CNS cultures may alter normal cell physiology and cell survival.

Antibodies↗
PubMed1995

Dramatic response to levamisole and low-dose prednisolone in 23 patients with oral lichen planus: a 6-year prospective follow-up study.

The purpose of this prospective study was to evaluate the short-term and long-term clinical efficacy of levamisole used with low-dose prednisolone in patients with refractory oral lichen planus. Twenty-three patients with OLP who had been treated unsuccessfully with other modalities were given 150 mg/day levamisole and 15 mg/day prednisolone for 3 consecutive days each week. Twelve patients showed dramatic remission of signs and symptoms within 2 weeks, whereas 11 had partial remission. All 23 reported significant pain relief and showed no evidence of erosive oral lichen planus after 4 to 6 weeks of treatment. All 23 also remained free from symptoms for 6 to 9 months after the treatment ended. There were few side effects from this treatment besides minor skin rash, headache, and insomnia from the levamisole in three cases. We conclude that the addition of levamisole to prednisolone may produce improved results in the management of erosive oral lichen planus.

Administration, Oral↗
PubMed1995

Novel reticular calcium binding protein is purified on taipoxin columns.

We identified, by affinity chromatography, two putative binding proteins for the presynaptic snake venom toxin taipoxin. We have previously characterized one of these proteins [neuronal pentraxin (NP)] as a neuronally secreted protein with homology to acute-phase proteins. Here we report the identification of the second protein as a 49-kDa lumenal calcium binding protein that we have named taipoxin-associated calcium binding protein 49 (TCBP-49). This protein contains six EF-hand putative calcium binding domains and the carboxyl-terminal sequence His-Asp-Glu-Leu (HDEL), identical to the yeast endoplasmic reticulum retention signal. Message for this protein is present in brain, liver, muscle, heart, kidney, and testis. Antibodies to this protein label reticular organelles of neurons and glia. This localization and the specific enrichment of native and recombinant TCBP-49 on columns of immobilized taipoxin raise the possibility that this protein interacts with internalized taipoxin, perhaps mediating its activation. The availability of pure TCBP-49 will allow direct tests of whether TCBP-49 alters the integrity of the oligomeric structure, phospholipase activity, or toxicity of taipoxin.

Amino Acid Sequence↗
PubMed1994

A technique for simultaneous replantation of multiple amputated digits at Tamai's Zone V.

A technique for simultaneously replanting multiple digits amputated at Tamai's Zone V is described. Since these multiple amputated digits are connected together, they should be replanted as a single unit. The technique includes applying the pneumatic tourniquet first, debridement, bone shortening, and fixation of all the amputated digits, including tendon repairs, application of vascular clamps before releasing the tourniquet, followed by vascular anastomosis in one-by-one fashion for each digit. The disadvantage of this technique is the difficulty in keeping the digit cool. The advantages are it is a less time-consuming operation, there is reduced blood loss and contamination, and there is a better axial arrangement of the bony framework.

Adolescent↗
PubMed1994

YY1 represses rat serum amyloid A1 gene transcription and is antagonized by NF-kappa B during acute-phase response.

Serum amyloid A (SAA), one of the major acute-phase proteins, increases several hundredfold in concentration in plasma following acute inflammation, primarily as a result of a 200-fold increase in its transcriptional rate. Functional analysis of the rat SAA1 promoter has identified a 65-bp cytokine response unit (CRU; positions -135 to -71) that could confer cytokine responsiveness on a heterologous promoter. Within this CRU, two cis-regulatory elements, corresponding to NF-kappa B- and C/EBP-binding sites, were found to be functionally important and exerted synergistic effects on induced SAA1 expression. In this report, we show that a third transcription factor interacts with the CRU through a region located between the NF-kappa B- and C/EBP-binding sites. On the basis of its gel mobility shift patterns, ubiquitous binding activity, sequence specificity of DNA binding, zinc-dependent binding activity, and gel mobility supershift by specific antibodies, we concluded that this factor is identical to YY1. Methylation interference studies revealed that YY1 binding sequences overlapped with those of NF-kappa B, and gel mobility studies showed that NF-kappa binding to the CRU was effectively inhibited by YY1. Consistent with its presumed antagonistic role to NF-kappa B, YY1 exerted a negative effect on SAA1 expression, whereas disruption of its binding in the promoter elevated basal and cytokine-induced activities. Furthermore, overexpression of YY1 trans-repressed SAA1 promoter activity. Thus, our results demonstrate that SAA1 expression is tightly regulated by an on-off switch of activators and repressors, presumably to ensure that it is expressed only under appropriate physiological conditions.

Acute-Phase Reaction↗
PubMed1994

[A clinical study of endodontic flare-ups].

The purpose of this study was to investigate the clinical variables influencing endodontic flare-ups. Three hundred and thirteen teeth receiving endodontic treatment at the Endodontic Department, Chang Gung Memorial Hospital were studied from December 1992 to February 1993. Among them, 21 teeth with significant pain and 9 with apical swelling were noted after the first appointment of treatment. Three teeth with persistent pain and one with apical swelling were also found one week after completion of endodontic therapy. The results showed significant improvement of clinical symptoms and signs one week after completion of endodontic treatment in comparison with pretreatment and after the first appointment (p < 0.025). The factors such as presence of pretreatment complaints, periapical lesions and vital pulp had significant effects on the incidence of endodontic flare-ups after the first appointment of treatment (P < 0.025). In contrast, patients' sex, the number of visits, and whether this was a retreatment case or not had no significant effect on the frequency of these endodontic flare-ups.

Acute Disease↗
PubMed1993

Sensitization of c-fos expression in rat striatum following multiple challenges with D-amphetamine.

D-Amphetamine transiently stimulates the expression of the immediate-early response gene, c-fos, in rat striatal cell nuclei. D-Amphetamine (2.5 mg/kg i.p.) induced a significantly greater expression of Fos-like immunoreactivity in striatum of rats treated three days previously with D-amphetamine compared to rats treated three days previously with saline. This increase in the expression of Fos-like immunoreactivity in rat striatum was characterized by a significantly greater number of immunoreactive nuclei and a significant increase in the intensity of the immunoreactivity. This sensitization of c-fos expression following a repeated administration of D-amphetamine indicates an increased activation of post-synaptic elements in rat striatum.

Animals↗
PubMed1992

Magnetic resonance imaging of neural transplants in rat brain using a superparamagnetic contrast agent.

Rat fetal brain tissue was incubated in vitro with superparamagnetic ferrite particles covalently coupled to the lectin wheat germ agglutinin (WGA) and transplanted into the adult rat striatum. At 6 days and at 3 weeks post-surgery the transplants were observed on T1 weighted magnetic resonance (MR) images of the rat head as an area of relatively low signal intensity which could be clearly differentiated from the higher signal intensity produced by the host brain. Histological analysis revealed that the ferrite particles were largely restricted to the transplant in a patchy distribution. The ferrite particles were associated with cells having an apparent normal morphology. Superparamagnetic ferrite particles act as potent MR contrast agents and can be used to label transplanted cells. The labeled cells are apparently not adversely affected by the WGA-ferrite particles and can be monitored for at least three weeks in vivo using noninvasive MR imaging.

Animals↗