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Biomedical subjects

G T Liu

Publications and source records attributed to G T Liu.

At least 19 recordsLinked to original sources
PubMed1997

Fas and Fas ligand expression in the salivary glands of patients with primary Sjögren's syndrome.

OBJECTIVE: To assess the role of Fas-mediated apoptosis in the salivary glands of patients with primary Sjögren's syndrome (SS). METHODS: Expression of Fas, Fas ligand (FasL), and bcl-2 in salivary gland biopsy material was detected in situ by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. DNA fragmentation in apoptotic cells was assessed by the enzymatic incorporation of labeled nucleotides (digoxigenin-dUTP). RESULTS: The acinar epithelial cells in SS were Fas+ and FasL+, and these cells died by apoptosis. The majority of infiltrating lymphocytes in SS were Fas+ and bcl-2+, while few lymphocytes expressed FasL. In situ detection of apoptosis showed minimal cell death of lymphocytes, particularly in dense periductal foci. Lymphocytic cell death was significantly lower (P < 0.0001) in these foci compared with that in the interstitium. CONCLUSION: Infiltrating lymphocytes in the focal lesions of the salivary glands of patients with SS are blocked in their ability to commit to apoptosis, even though they may express Fas. The presence of bcl-2 in these cells may explain their inability to undergo apoptosis. The acinar epithelial cells, in contrast, may undergo Fas-mediated apoptosis. These results suggest that the Fas death pathway may be an important mechanism leading to the glandular destruction found in SS.

Apoptosis↗
PubMed1996

Effects of salvianolic acid A on oxygen radicals released by rat neutrophils and on neutrophil function.

Salvianolic acid A (Sai A) has demonstrated potent antioxidant activity in previous studies. In the present study, the effects of Sai A on oxygen radicals released by rat neutrophils and on neutrophil function were investigated. Superoxide anion assayed by the nitroblue tetrazolium test and hydrogen peroxide detected with redox of scopoletin were scavenged concentration dependently by Sai A in n-formyl-methionyl-leucylphenylalanine (fMLP)- and phorbol myristate acetate (PMA)-stimulated rat neutrophils. Hydroxyl radicals generated in PMA-stimulated neutrophils, measured by HPLC, also were scavenged significantly by Sai A, whereas Sai A showed no significant effects on chemotaxis toward fMLP and phagocytosis of latex beads by rat neutrophils. In addition, the intracellular free calcium and cyclic nucleotide levels of neutrophils, when stimulated by fMLP, were not affected by Sai A. These results suggest that Sai A could significantly scavenge oxygen radicals released by activated neutrophils without affecting their functional ability.

Animals↗
PubMed1996

Lymphocyte apoptosis and apoptosis-associated gene expression in Sjögren's syndrome.

OBJECTIVE: To study the mechanism and regulation of apoptosis in peripheral blood T and B lymphocytes from patients with Sjögren's syndrome (SS). METHODS: The mode of in vitro lymphocyte death in the peripheral blood of patients with SS was determined by fluorescence microscopic analysis, terminal deoxynucleotidyl transferase assay, and DNA fragmentation analysis. Apoptotic cell death of T and B cells was determined at 48 hours of culture by fluorescence-activated cell sorter analysis of propidium iodidestained cells. Messenger RNA (mRNA) expression of bcl-2, bcl-x, bax, and c-myc in T and B cells was determined by enzyme-linked immunosorbent assay-polymerase chain reaction (ELISA-PCR). Expression of bcl-xL and bcl-xS was determined by Southern blot analysis of PCR products. Gene expression was calculated as the ratio of each gene message to the message of the GAPDH gene. Bcl-2 protein levels in SS T cells were determined by ELISA. RESULTS: SS T cells showed increased in vitro apoptosis compared with normal T cells (mean +/- SD 12.3 +/- 4.5% versus 7.3 +/- 2.0%; P < 0.01). Freshly isolated SS T cells showed increased expression of bcl-2 mRNA compared with normal controls (mean +/- SD 1.50 +/- 0.65 versus 0.88 +/- 0.23; P < 0.05). There was no significant difference in levels of bax or c-myc mRNA in T cells and B cells between SS patients and normal controls. When SS T lymphocytes were cultured in vitro for 72 hours, Bcl-2 protein levels decreased with time. CONCLUSION: SS T cells showed accelerated apoptosis in vitro. Freshly isolated SS T cells had increased expression of bcl-2. An increase in death-promoter signals and decrease in death-suppressor signals in vitro may have been responsible, in part, for the apoptosis in SS T lymphocytes.

Adult↗
PubMed1996

Varicella-zoster ventriculo-encephalitis and spinal cord infarction in a patient with AIDS.

Varicella-zoster virus (VZV) infection is usually benign and self-limited. However, particularly in the immunosuppressed host, serious central nervous system complications may occur, including encephalitis, myelitis, and cerebral vascular occlusion. We report the case of a 57-year-old male with AIDS, who rapidly developed a sixth cranial nerve palsy and progressive myelopathy. There was no antecedent zoster rash. Autopsy revealed VZV ventriculo-encephalitis and vasculitis, as well as a transverse infarction of the spinal cord without evidence of direct infection of the cord parenchyma. Spinal cord infarction secondary to VZV vasculitis is an unusual cause of myelopathy in immunosuppressed patients.

AIDS-Related Opportunistic Infections↗
PubMed1996

Severe sudden visual loss caused by pseudotumor cerebri and lumboperitoneal shunt failure.

PURPOSE: Severe vistral acuity loss associated with pseudotumor cerebri is usually caused by chronic optic disk edema or a retinal abnormality. METHODS: We treated a women, with known pseudotumor cerebri treated with a lumboperitoneal shunt, who developed acute pallied optic disk swelling and visual acuity of R.E.: no light perception and L.E.: 20/70 in association with lumboperitoneal shunt failure. There were no contributory retinal lesions. RESULTS: The patient underwent optic nerve sheath fenestration and lumboperitoneal shunt revision. Visual acuity improved to 20/20 in both eyes. The papilledema resolved. CONCLUSION: The severe sudden visual loss was attributed to axoplasmic stasis and optic nerve ischemia associated with a sudden rise in intracranial pressure.

Adult↗
PubMed1996

Prominent proptosis in childhood thyroid eye disease.

BACKGROUND: Orbital signs and symptoms occur in approximately one half of children with Graves disease, but the symptoms are usually minor and limited to the eyelids. Prominent proptosis is uncommon in children with this disorder. METHODS: Review of eight children with prominent proptosis associated with thyroid eye disease. Four patients were treated at the Children's Hospital of Philadelphia, the other four at the Columbia Presbyterian Medical Center. RESULTS: At initial presentation, children ranged in age from 3 to 16 years. There were five girls and three boys. Seven of eight children had hyperthyroidism at ophthalmic presentation. Four patients had restrictive myopathy, and all of the seven patients who underwent neuroimaging had extraocular muscle enlargement. Five patients were treated with lubrication. Two underwent orbital fat decompression. One patient had thyroid eye disease and myasthenia gravis. CONCLUSIONS: Proptosis in childhood thyroid eye disease usually is associated with a hyperthyroid state. The proptosis may be dramatic, but corneal exposure and restrictive myopathy are seen in only some of the patients. Neuroimaging shows enlarged extraocular muscles. Most children with this complication can be treated conservatively with topical lubrication, but orbital fat decompression may be considered in patients with more advanced conditions.

Adolescent↗
PubMed1996

Diagnostic tests in neuro-ophthalmology.

This article reviews the diagnostic testing used in the evaluation of several common neuro-ophthalmologic entities including optic nerve disease, pseudotumor cerebri, anisocoria, ptosis, and ocular motor palsies. Emphasis is placed on these bedside tests that help to establish the diagnosis of these common clinical problems. The utility of the cocaine and Tensilon (edrophonium chloride) tests as well as the role of neuroimaging in these conditions are reviewed.

Brain Diseases↗
PubMed1996

Gangliogliomas involving the optic chiasm.

We report three patients with gangliogliomas involving the optic chiasm via distinct mechanisms. The ganglioglioma in one patient likely originated in the temporal lobe and spread medially to involve the chiasm, and diffuse spinal cord dissemination also occurred. Chiasmal involvement in this manner and dissemination at presentation are unusual for gangliogliomas. The tumor in a second patient was intrinsic to the hypothalmus and chiasm, while in the third patient, it involved both optic tracts, and a cyst compressed the chiasm laterally. Two patients developed severe bilateral visual loss, while the other had a stable bitemporal hemianopsia. Two patients received radiotherapy, but one continued to lose vision. Although gangliogliomas rarely involve chiasm, the mechanisms by which they produce chiasmal visual loss may be diverse, and the long-term visual prognosis is variable.

Adolescent↗
PubMed1996

[Effect of dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2, 2'-dicarboxylate (DDB) on several phenotypes of Bel-7402 hepatocarcinoma cell line and its mechanism].

DDB is a hepatoprotectant and has been widely used for the treatment of chronic viral hepatitis in China. The drug markedly improved the abnormal liver function particularly in lowering the elevated serum transaminases in patients. It is known that there is a close correlation between primary hepatocarcinoma and chronic viral hepatitis. The aim of the present study is to evaluate the effect of DDB on hepatocarcinoma cell line. The results showed that the growth and clonogenicity of Bel-7402 human hepatocarcinoma cell line cultured with DDB were markedly inhibited. The nucleoles of the cells treated with DDB disappeared or their numbers and nucleus/cytoplasm ratio decreased under electron microscopic observation. DDB at the concentration of 10(-4) mol.L-1 significantly increased the contents of cAMP and calmodulin (CaM) in Bel-7402 hepatocarcinoma cells. DDB was also found to inhibit topoisomerase II activity of Bel-7402 hepatocarcinoma cells. These results suggest that the mechanism of inhibition of DDB on several phenotypes of Bel-7402 cell line may be related to its effect on cAMP and CaM content as well as topoisomerase II activity.

Antineoplastic Agents↗
PubMed1996

Eyelid lag without eyelid retraction in pretectal disease.

We report a patient with pretectal eyelid lag without retraction. MRI showed high signal abnormality dorsal to the right red nucleus in a region thought responsible for premotor eyelid control. The dissociation of eyelid lag from eyelid retraction in this patient would suggest that these lid signs may have separate neural mechanisms or pathways. We propose that the lesion interrupts inhibitory connections between the vertical gaze center and the central caudal nucleus.

Adult↗
PubMed1995

Role of nitric oxide in immunological liver damage in mice.

The role of nitric oxide (NO) in immunological liver injury in mice was studied. Moderate increases in plasma NO levels and liver damage were seen after the injection of either Bacillus Calmette-Guérin (BCG) or lipopolysaccharide (LPS) alone in mice. Administration of LPS following BCG injection resulted in a remarkable elevation of the plasma NO level and severe liver damage. The elevation of the NO level and the liver damage induced by BCG or BCG + LPS were not affected by the administration of L-arginine. The BCG-induced increase of plasma NO was inhibited by NG-monomethyl-L-arginine (NMA) treatment without effect on the elevated plasma glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) levels. The BCG + LPS-induced elevation of plasma GPT and GOT levels was more pronounced after NO production was inhibited by NMA treatment. The action of NMA mentioned above was partially reversed by the simultaneous administration of L-arginine. These findings suggest that NO plays a protective role against liver injury induced by BCG+LPS in mice.

Animals↗
PubMed1995

The crossed paralyses. The original brain-stem syndromes of Millard-Gubler, Foville, Weber, and Raymond-Cestan.

In this article, the crossed syndromes of Millard-Gubler (facial palsy and contralateral hemiparesis), Foville (facial palsy, conjugate gaze paralysis, and contralateral hemiparesis), Weber (oculomotor palsy and contralateral hemiparesis), and Raymond-Cestan (internuclear ophthalmoplegia and contralateral hemiparesis) are detailed from the original reports. These and other related syndromes were instrumental in establishing important principles in brain-stem localization: the occurrence of cranial nerve palsies contralateral to hemibody motor or sensory disturbances, the concepts of the medial longitudinal fasciculus and conjugate gaze, and the corticobulbar innervation of the facial nerve nucleus.

Brain Stem↗
PubMed1995

Tuberculous meningitis with blindness and perichiasmal involvement on MRI.

An 11-year-old boy with tuberculous meningitis developed blindness, a rare complication of this disease in the United States. Magnetic resonance imaging demonstrated perichiasmal enhancement, suggesting that arachnoiditis caused the visual loss. Serial neuroimaging over 7 months revealed a persistent inflammatory process in the chiasmatic cistern, hydrocephalus, and progressive cerebral infarctions.

Arachnoiditis↗
PubMed1995

Optic disk swelling and abducens palsies associated with OKT3.

PURPOSE/METHODS: Orthoclone OKT3 is a monoclonal murine IgG immunoglobulin used to treat acute cellular rejection of allografted organs. Aseptic meningitis and meningoencephalopathy are known adverse side effects from the drug. OKT3 caused additional ophthalmologic and neurologic complications in an 18-year-old woman who was treated for transplanted kidney graft rejection. Papilledema and bilateral abduction deficits developed. RESULTS/CONCLUSIONS: Results of magnetic resonance imaging and magnetic resonance angiography were unremarkable. Lumbar puncture disclosed increased intracranial pressure and sterile meningeal inflammation. Most of the symptoms resolved by one week after discontinuation of OKT3. Ophthalmologists and neurologists should be aware that optic disk swelling and abducens palsies can be associated with OKT3 when used in the treatment of transplanted kidney graft rejection.

Abducens Nerve↗
PubMed1995

Tonic pupil and orbital glial-neural hamartoma in infancy.

PURPOSE/METHODS: Tonic pupils in early childhood are rare. We studied an otherwise healthy 31/2-month-old girl who had a right pupil that was poorly reactive to light, without other signs of oculomotor nerve palsy. RESULTS/CONCLUSIONS: Constriction of the right pupil after instillation of 0.125% pilocarpine eyedrops confirmed denervation hypersensitivity, consistent with a tonic pupil. There was no strabismus or proptosis. A magnetic resonance imaging scan demonstrated a right orbital mass, interposed between the lateral and inferior recti muscles. Biopsy was consistent with a benign, glial-neural hamartoma. Thus, in this young patient, a tonic pupil was associated with a benign orbital mass.

Child, Preschool↗