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1.
Hong Kong Med J ; 24(4): 378-383, 2018 08.
Article in English | MEDLINE | ID: mdl-30065125

ABSTRACT

INTRODUCTION: In Hong Kong, persons in custody receive primary medical care within the institutions of the Correctional Services Department (CSD). However, for psychiatric care, persons in custody must attend specialist out-patient clinics (SOPCs), which may cause embarrassment and stigmatisation. The aim of this interventional pilot study was to compare teleconsultations with face-to-face consultations for a group of stable Chinese psychiatric out-patients in custody. METHODS: A total of 86 stable Chinese male out-patients in custody were recruited for psychiatric teleconsultations. They were compared with 249 age-matched Chinese male out-patients in custody attending standard face-to-face psychiatric consultations at other SOPCs. The two groups had comparable baseline characteristics including age, education level, and 12-item Chinese General Health Questionnaire (C-GHQ-12) score. A satisfaction survey of patients towards the teleconsultation was also carried out. RESULTS: Compared with the face-to-face consultation group, the teleconsultation group showed a significantly better result in the difference in C-GHQ-12 scores before and after consultations (P=0.023). The correlation between the first and second teleconsultations also showed a moderate positive relationship (r=0.309). The satisfaction survey showed a favourable response to teleconsultations. No significant adverse events were identified for the teleconsultation group. CONCLUSIONS: The results suggest that teleconsultations are a sustainable and safe alternative to face-to-face consultations for stable Chinese psychiatric out-patients in custody.


Subject(s)
Mental Disorders/therapy , Outpatients/psychology , Prisoners/psychology , Remote Consultation/methods , Adult , Hong Kong , Humans , Male , Middle Aged , Pilot Projects , Surveys and Questionnaires
3.
Hong Kong Med J ; 13(6): 478-81, 2007 Dec.
Article in English | MEDLINE | ID: mdl-18057438

ABSTRACT

Gastro-intestinal stromal tumours are rarely found in the oesophagus and it is uncommon for these tumours to present with rupture. In this paper, we report a case where the tumour ruptured through the distal oesophagus. As a result, the patient underwent surgical tumour dissection. A histopathological examination of the tumour mass confirmed that it was a gastro-intestinal stromal tumour. In this report, we review the diagnosis, pathology, and treatment of a patient presenting with a ruptured oesophageal gastro-intestinal stromal tumour.


Subject(s)
Esophageal Neoplasms/complications , Gastrointestinal Stromal Tumors/complications , Pleural Cavity/pathology , Adult , Esophageal Neoplasms/diagnostic imaging , Esophageal Neoplasms/pathology , Gastrointestinal Stromal Tumors/diagnostic imaging , Gastrointestinal Stromal Tumors/pathology , Humans , Male , Rupture, Spontaneous , Tomography, X-Ray Computed
4.
Br J Radiol ; 79(941): 368-71, 2006 May.
Article in English | MEDLINE | ID: mdl-16632615

ABSTRACT

The objective of this study was to evaluate the clinical safety of intravenous gadolinium-based contrast media used in patients who underwent MRI at a single institution. Acute adverse reactions to intravenous gadolinium-based contrast media used for MRI at the Princess Margaret Hospital, Hong Kong, SAR, from January 1999 to November 2004 were recorded in an incidence log book. The medical records of patients' demographics were retrospectively reviewed and the nature, frequency and severity of the adverse reactions were investigated and documented. The incidence of acute adverse reactions to intravenous gadolinium-based contrast media was 0.48% (45 patients with 46 adverse reactions). The severity of these adverse reactions were 96% mild, 2% moderate (one patient developed shortness of breath that required oxygen supplementation and intravenous steroidal management) and 2% severe (one patient developed an anaphylactoid reaction, but successfully recovered through timely resuscitation). No patients were recorded as having contrast extravasation and none died as a result of any adverse reaction. Among the 45 patients who developed adverse reactions, three patients (6.7%) had prior adverse reactions to iodinated contrast media, three (6.7%) had prior reactions to a different gadolinium-based contrast agent, one (2%) had asthma and nine (20%) had a history of drug/food allergy. Overall, 41% of the adverse reactions were not documented in the final MRI report or the clinical medical records. Gadolinium-based contrast media are safe and well tolerated by the vast majority of patients. In our study, the adverse reaction rate (0.48%) and the incidence of severe anaphylactoid reaction (0.01%) concur with those reported in the literature. Although most of the symptoms are mild and transient, these adverse reactions must be accurately documented and managed.


Subject(s)
Contrast Media/adverse effects , Drug Hypersensitivity/etiology , Gadolinium DTPA/adverse effects , Magnetic Resonance Imaging , Acute Disease , Adolescent , Adult , Aged , Anaphylaxis/etiology , Asthma/complications , Child , Dyspnea/etiology , Female , Hong Kong , Humans , Hypersensitivity, Delayed/complications , Incidence , Injections, Intravenous , Male , Middle Aged , Nausea/etiology , Osmolar Concentration , Recurrence , Retrospective Studies , Urticaria/etiology
5.
Oncogene ; 7(4): 667-76, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1314368

ABSTRACT

Mice carrying an H-2K-v-jun transgene develop malignant sarcomas by a multistage mechanism following wounding. Here we show that these malignancies are often heterogeneous in composition, containing both undifferentiated mesenchymal cells as well as focal areas of skeletal muscle. Such myogenic areas are not detectable in premalignant precursor lesions, suggesting that cells competent for muscle differentiation arise at a late stage of tumorigenesis. Immunohistochemical staining of transgenic sarcomas reveals that levels of v-Jun correlate inversely with muscle-specific gene expression, suggesting that high levels may be inhibitory to myogenesis. Consistent with this idea, we demonstrate that whereas high levels of v-Jun are able to block MyoD-dependent gene expression in vitro, the levels of v-Jun in sarcoma-derived myogenic cells are below the threshold required to produce this effect. The cell of origin of v-jun wound sarcomas, as well as the relationship between myogenic determination and multistage tumorigenesis, are discussed in the light of these results.


Subject(s)
Oncogene Protein p65(gag-jun)/physiology , Sarcoma, Experimental/pathology , Actins/metabolism , Animals , Cell Differentiation , Desmin/metabolism , Gene Expression , Genes, jun , Mice , Mice, Transgenic , Muscle Proteins/genetics , Muscle Proteins/metabolism , Muscles/pathology , MyoD Protein , Myogenin , RNA, Messenger/genetics , RNA, Neoplasm/genetics , Time Factors , Vimentin/metabolism , Wound Healing
6.
Oncogene ; 34(7): 878-89, 2015 Feb 12.
Article in English | MEDLINE | ID: mdl-24608426

ABSTRACT

Nasopharyngeal carcinoma (NPC) is a cancer that occurs in high frequency in Southern China. A previous functional complementation approach and the subsequent cDNA microarray analysis have identified that serum amyloid A1 (SAA1) is an NPC candidate tumor suppressor gene. SAA1 belongs to a family of acute-phase proteins that are encoded by five polymorphic coding alleles. The SAA1 genotyping results showed that only three SAA1 isoforms (SAA1.1, 1.3 and 1.5) were observed in both Hong Kong NPC patients and healthy individuals. This study aims to determine the functional role of SAA1 polymorphisms in tumor progression and to investigate the relationship between SAA1 polymorphisms and NPC risk. Indeed, we have shown that restoration of SAA1.1 and 1.3 in the SAA1-deficient NPC cell lines could suppress tumor formation and angiogenesis in vitro and in vivo. The secreted SAA1.1 and SAA1.3 proteins can block cell adhesion and induce apoptosis in the vascular endothelial cells. In contrast, the SAA1.5 cannot induce apoptosis or inhibit angiogenesis because of its weaker binding affinity to αVß3 integrin. This can explain why SAA1.5 has no tumor-suppressive effects. Furthermore, the NPC tumors with this particular SAA1.5/1.5 genotype showed higher levels of SAA1 gene expression, and SAA1.1 and 1.3 alleles were preferentially inactivated in tumor tissues that were examined. These findings further strengthen the conclusion for the defective function of SAA1.5 in suppression of tumor formation and angiogenesis. Interestingly, the frequency of the SAA1.5/1.5 genotype in NPC patients was ~2-fold higher than in the healthy individuals (P=0.00128, odds ratio=2.28), which indicates that this SAA1 genotype is significantly associated with a higher NPC risk. Collectively, this homozygous SAA1.5/1.5 genotype appears to be a recessive susceptibility gene, which has lost the antiangiogenic function, whereas SAA1.1 and SAA1.3 are the dominant alleles of the tumor suppressor phenotype.


Subject(s)
Gene Expression Regulation, Neoplastic , Genetic Predisposition to Disease , Nasopharyngeal Neoplasms , Neovascularization, Pathologic , Polymorphism, Genetic , Serum Amyloid A Protein , Tumor Suppressor Proteins , Alleles , Apoptosis , Carcinoma , Cell Adhesion , Cell Line, Tumor , Coculture Techniques , Endothelial Cells , Humans , Nasopharyngeal Carcinoma , Nasopharyngeal Neoplasms/genetics , Nasopharyngeal Neoplasms/metabolism , Nasopharyngeal Neoplasms/pathology , Neovascularization, Pathologic/genetics , Neovascularization, Pathologic/metabolism , Neovascularization, Pathologic/pathology , Serum Amyloid A Protein/biosynthesis , Serum Amyloid A Protein/genetics , Tumor Suppressor Proteins/biosynthesis , Tumor Suppressor Proteins/genetics
7.
AIDS ; 9(2): 137-43, 1995 Feb.
Article in English | MEDLINE | ID: mdl-7536422

ABSTRACT

OBJECTIVE: To investigate the induction of cytokines as a possible mechanism for the neurotoxicity of the HIV-1 envelope protein gp120. DESIGN: The gp120 protein was tested directly on primary human brain cultures to examine its ability to induce cytokines and its neurotoxicity on human neural cells because gp120 is known to be toxic to rodent ganglion cultures, and neural cells such as astrocytes and microglia produce cytokines when stimulated. METHODS: Primary cultures of human brain cell aggregates, astrocytes and macrophages were exposed to HIV-1 recombinant (r) gp120SF2. Induction of cytokines was assayed by enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR); neurotoxicity of rgp120SF2 and interleukin (IL)-6 on human brain cultures was examined by electron microscopy. RESULTS: ELISA and RT-PCR studies revealed that rgp120SF2 induced IL-6 and tumor necrosis factor (TNF)-alpha in brain cultures; IL-6 could also be induced by TNF-alpha added to brain cultures. Both IL-6 and TNF-alpha were upregulated in astrocytes and macrophage cultures on rgp120SF2 treatment. Ultrastructural studies demonstrated that IL-6 treatment for 72 h induced large cytoplasmic vacuoles in neural cells with morphology consistent with neurons; rgp120SF2 treatment for 7 days resulted in chromatin condensation along the inner margins of nuclear envelopes of neural cells. CONCLUSIONS: Our results demonstrated that HIV-1 rgp120SF2 can upregulate at least two known neurotoxic cytokines, IL-6 and TNF-alpha, which may injure neural cells and contribute to the neuropathology observed in AIDS dementia patients.


Subject(s)
Brain/drug effects , HIV Envelope Protein gp120/toxicity , Interleukin-6/biosynthesis , Tumor Necrosis Factor-alpha/biosynthesis , Astrocytes/drug effects , Astrocytes/metabolism , Astrocytes/ultrastructure , Base Sequence , Brain/metabolism , Brain/ultrastructure , Cell Death , Cells, Cultured , Culture Media , DNA, Complementary , Humans , Interleukin-6/toxicity , Macrophages/drug effects , Macrophages/ultrastructure , Microscopy, Electron , Molecular Sequence Data , RNA/biosynthesis , Tumor Necrosis Factor-alpha/toxicity
8.
AIDS ; 12(4): 349-54, 1998 Mar 05.
Article in English | MEDLINE | ID: mdl-9520163

ABSTRACT

OBJECTIVES: This study examines the cytotoxicity potential and the mechanism of toxicity of the HIV-1 gp120 on human neuroblastoma cells. DESIGN: Previous data from our group have suggested that the HIV-1 envelope protein gp120 promotes the secretion of tumor necrosis factor-alpha and other factors by astrocytes and microglial cells present in primary human brain cell cultures, thereby contributing to the injury of neurons in these cultures. This study investigates the cytotoxicity potential and the mechanism of toxicity of gp120 on human neuroblastoma cells. METHODS: SK-N-SH cells were treated with HIV-1 gp120, and was followed by in situ DNA fragmentation staining and small molecular weight DNA extraction studies to ascertain the induction of apoptosis by gp120 in these cells. To evaluate a potential role of the growth suppressor gene p53, gp120-treated SK-N-SH cells were subjected to reverse transcription polymerase chain reaction (RT-PCR) and Western blot analyses for the induction of p53. An antisense oligodeoxynucleotide against p53 was used to investigate the role of p53 in the gp120-induced apoptosis in these cells. RESULTS: Data from T7 DNA polymerase staining and small molecular weight DNA extraction studies demonstrated that gp120-induced DNA breakage in SK-N-SH cells with fragmentation patterns characteristic of apoptosis. RT-PCR and Western blot analyses revealed that the gp120-mediated induction of apoptosis was dependent on a gp120-induced and gp120-sustained upregulation of p53. The induction of p53 by gp120 was specific, since an antibody against gp120 prevented both the induction of p53 and subsequent apoptosis in SK-N-SH cells. The critical role of p53 was further illustrated by the effectiveness of a p53 antisense oligodeoxynucleotide to inhibit the gp120-induced apoptosis. As a control, the apoptosis-inducing potential of gp120 on SK-N-SH cells was not seen in the HIV-1 Gag proteins even when used at up to 5 nM. CONCLUSIONS: These results established that HIV-1 gp120 is potentially cytotoxic to human neuronal cells through the induction of p53, which may eventually lead to induction of apoptosis.


Subject(s)
Apoptosis , Genes, p53 , HIV Envelope Protein gp120/pharmacology , Oligonucleotides, Antisense/pharmacology , Blotting, Western , DNA Fragmentation , Humans , Neuroblastoma , Oligonucleotides, Antisense/genetics , Polymerase Chain Reaction , Transcription, Genetic , Tumor Cells, Cultured , Up-Regulation
9.
Am J Med ; 76(1): 31-7, 1984 Jan.
Article in English | MEDLINE | ID: mdl-6691359

ABSTRACT

The interrelation between leukocyte count, cigarette smoking, and pulmonary function results was examined in two work populations: 1,826 white male workers in a pulp and paper mill and 1,620 white male workers in an aluminum smelter in British Columbia. These workers took part in epidemiologic health studies that consisted of a medical-occupational questionnaire, spirometric measurements, and leukocyte count. Measurements of the air contaminants in the work environment were also carried out simultaneously by personal and area sampling. No significant increase in the prevalence of respiratory symptoms and lung function abnormalities was found between the exposed and nonexposed workers in each work population. Similarly, no difference in leukocyte count was found between exposed and nonexposed workers. Leukocyte count was found to be significantly higher among current smokers than nonsmokers and former smokers in each population. In both populations, there was an inverse correlation between leukocyte count and one-second forced expiratory volume and forced vital capacity of the workers irrespective of the smoking habit. This finding suggests that the leukocyte response to external stimuli may be another determinant of lung function measurements.


Subject(s)
Leukocyte Count , Lung/physiopathology , Smoking , Adult , Age Factors , Aged , British Columbia , Bronchitis/epidemiology , Forced Expiratory Volume , Humans , Male , Middle Aged , Respiratory Function Tests
10.
J Med Chem ; 32(9): 2128-34, 1989 Sep.
Article in English | MEDLINE | ID: mdl-2570151

ABSTRACT

An evaluation of 6-[2-(di-n-propylamino)ethyl]indole (4), its rigid analogue N,N-di-n-propyl-5,6,7,8-tetrahydrobenz[f]indol-7-amine (5), and some related congeners, for ability to suppress serum prolactin in reserpinized rats, revealed modest biological activity in this in vivo model of dopaminergic activity. Although the indole N-H in these compounds can be considered to be oriented "meta" with respect to the ethylamine side chain, compounds with the indole N-H located in the other "meta" position (i.e. 4-[2-(di-n-propylamino)ethyl]indole (2) or its rigid benz[e]indole analogue 3) were much more potent dopamine agonists. The results argue for a particular orientation of the indole N-H vector. In addition, relatively potent dopamine agonists also resulted when the pyrrole portion of the indole ring was replaced by a methanesulfonamido function, supporting the idea that the indole N-H serves as a hydrogen-bond donor.


Subject(s)
Dopamine Agents/chemical synthesis , Indoles/chemical synthesis , Animals , Chemical Phenomena , Chemistry , Dopamine Agents/pharmacology , Hydroxylation , Male , Prolactin/antagonists & inhibitors , Prolactin/blood , Rats , Rats, Inbred Strains , Receptors, Dopamine/drug effects , Receptors, Dopamine D2 , Structure-Activity Relationship
11.
Pediatr Infect Dis J ; 15(7): 563-75, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8823848

ABSTRACT

Recent advances in basic science and clinical trials have demonstrated that IFNs and myeloid hematopoietins play crucial roles in host defense against pathogens and immune surveillance. Here we have reviewed the biologic functions of GM-CSF, G-CSF, IFN-alpha and IFN-gamma. For patients with neutropenia resulting from cytotoxic chemotherapy, bone marrow transplantation, congenital agranulocytosis and cyclic neutropenia, therapeutic uses of GM-CSF and G-CSF were reviewed. Application of these growth factors to patient management represents a major contribution of biotechnology to a difficult area of therapeutics in febrile, neutropenic patients. Because IFN-alpha plays crucial roles in antiviral responses, its clinical applications in hepatitis B and C, human papilloma virus, HIV infection and malignancy were discussed. The use of IFN-gamma in bacterial prophylaxis in patients with chronic granulomatous disease was also presented. Advances in clinical applications of IFNs and hematopoietic growth factors serve as a paradigm for further development to investigate the use of other important cytokines in modern therapeutics.


Subject(s)
Granulocyte-Macrophage Colony-Stimulating Factor , Interferons , Neutropenia/therapy , Granulocyte Colony-Stimulating Factor/physiology , Granulocyte Colony-Stimulating Factor/therapeutic use , Granulocyte-Macrophage Colony-Stimulating Factor/physiology , Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use , Humans , Interferons/physiology , Interferons/therapeutic use , Neutropenia/etiology
12.
Life Sci ; 35(13): 1343-8, 1984 Sep 24.
Article in English | MEDLINE | ID: mdl-6482656

ABSTRACT

A series of three isomeric 2,4,5-substituted monoethoxy dimethoxy phenylisopropylamines were compared for their contractile effect in the rat fundus as potential antagonists to the effect of serotonin in the fundus. The three isomers were also evaluated for their discriminative stimulus properties in rats that had been trained to discriminate injections of saline from LSD tartrate (0.08 mg/kg). The drug discrimination studies revealed that the 2,5-dimethoxy-4-ethoxy substitution was most potent in rats, consistent with the reported clinical activity of this isomer in man. By contrast, of the three isomers examined, this was the weakest in eliciting a contraction in the fundus. None of the compounds antagonized serotonin induced contractions, and it was not possible to determine pA2 values. Questions are raised about the determination of pA2 values for partial agonists and it is concluded that the fundus is not a reliable model for prediction of hallucinogenic activity of phenethylamines.


Subject(s)
Gastric Fundus/drug effects , Hallucinogens , Phenethylamines/pharmacology , Receptors, Serotonin/drug effects , Animals , Discrimination, Psychological/drug effects , Gastric Fundus/innervation , In Vitro Techniques , Lysergic Acid Diethylamide/pharmacology , Male , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , Rats , Rats, Inbred Strains , Serotonin Antagonists
13.
Can J Neurol Sci ; 20(1): 59-61, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8467431

ABSTRACT

This report highlights the clinical features of two patients who presented with severe neuropathic chest wall pain caused by herniated C6-7 disc, and speculates on the pathophysiology of this syndrome. Worsening of symptoms with neck movement helped localize the process as cervical spine rather than plexus in origin. Both patients had herniated C6-7 disc material compressing the spinal cord and C7 nerve root, and neurological symptoms resolved promptly following surgery. Neuropathic chest wall pain should alert the clinician to consider the diagnosis of cervical disc herniation and prompt definitive imaging of the cervical spine by myelography or magnetic resonance imaging (MRI).


Subject(s)
Cervical Vertebrae , Chest Pain/etiology , Intervertebral Disc Displacement/diagnosis , Adult , Female , Humans , Intervertebral Disc Displacement/diagnostic imaging , Intervertebral Disc Displacement/surgery , Middle Aged , Spinal Fusion , Tomography, X-Ray Computed
16.
J Biol Chem ; 273(39): 25198-202, 1998 Sep 25.
Article in English | MEDLINE | ID: mdl-9737981

ABSTRACT

Despite what is known about the early signaling events in tumor necrosis factor (TNF) alpha-induced apoptosis, characterization of the downstream events remains largely undefined. It is now known that a cross-talk exists between the interferon and TNF-alpha pathways. This linkage allows recruitment of the cell proliferation suppressor PKR (dsRNA-dependent protein kinase) from the interferon pathway to play a pivotal role in TNF-alpha-induced apoptosis. In this study, we took advantage of the differential TNF-alpha susceptibilities of human promonocytic U937 subclones, deficient in or overexpressing PKR, to further characterize the role of PKR in apoptosis. By reverse transcription-polymerase chain reaction, we demonstrated that TNF-alpha transiently induces the tumor suppressor p53 in U937 cells. This p53 induction lags behind the TNF-alpha induction of PKR by 1 h. By cell viability determination, ultrastructural studies, apoptotic DNA laddering, and antisense techniques, it was shown that inhibition of p53 expression in PKR-overexpressing U937 cells abrogates the TNF-alpha-induced apoptosis in these cells. Conversely, overexpressing wild type p53 in PKR-deficient U937 cells confers the susceptibility of these cells to TNF-alpha-induced apoptosis. This latter result indicates that p53 induction is an event downstream of TNF-alpha-induced up-regulation of PKR, thereby further establishing the critical role of p53 in TNF-alpha-induced apoptosis in U937 cells. PKR-overexpressing U937 cells were found to possess a constitutively higher level of p53, which partly explains why these cells spontaneously undergo apoptosis even without TNF-alpha treatment. Finally, a model is presented on the interplay between PKR and p53 in effecting TNF-alpha-induced apoptosis in U937 cells.


Subject(s)
Apoptosis , Tumor Necrosis Factor-alpha/metabolism , Tumor Suppressor Protein p53/metabolism , eIF-2 Kinase/metabolism , Base Sequence , Cell Line , DNA Primers , Humans , Kinetics , Microscopy, Electron , Nucleosomes/metabolism , Tumor Suppressor Protein p53/biosynthesis
17.
Int J Biochem ; 15(4): 523-9, 1983.
Article in English | MEDLINE | ID: mdl-6221961

ABSTRACT

1. A mutant of Neurospora crassa has been isolated whose pyruvate kinase is twice as active as the wild type enzyme. 2. The purified mutant and the wild type enzymes exhibit similar immunological properties, pI values (6.4) and Arrhenius activation energy (11.2 kcal/mol). 3. Both the enzymes show hyperbolic saturation kinetics with ADP and sigmoidal kinetics with PEP. 4. The mutant enzyme displays a higher affinity for PEP and a greater extent of cooperativity in binding than the wild type. 5. Conformational alterations in the mutant enzyme are inferred on the basis of electrophoretic analyses and denaturation by urea, SDS and heat.


Subject(s)
Mutation , Neurospora crassa/enzymology , Neurospora/enzymology , Pyruvate Kinase/isolation & purification , Hot Temperature , Kinetics , Neurospora crassa/genetics , Pyruvate Kinase/genetics , Pyruvate Kinase/metabolism , Sodium Dodecyl Sulfate/pharmacology , Thermodynamics , Urea/pharmacology
18.
Proc Natl Acad Sci U S A ; 93(22): 12451-5, 1996 Oct 29.
Article in English | MEDLINE | ID: mdl-8901602

ABSTRACT

Tumor necrosis factor alpha (TNF-alpha) is well-characterized for its necrotic action against tumor cells; however, it has been increasingly associated with an apoptosis-inducing potential on target cells. While the signaling events and the actual cytolytic mechanism(s) for both TNF-alpha-induced necrosis and apoptosis remain to be fully elucidated, we report here on (i) the ability of TNF-alpha to induce apoptosis in the promonocytic U937 cells, (ii) the discovery of a cross-talk between the TNF-alpha and the interferon signaling pathways, and (iii) the pivotal role of interferon-inducible, double-stranded RNA-activated protein kinase (PKR) in the induction of apoptosis by TNF-alpha. Our data from microscopy studies, trypan blue exclusion staining, and apoptotic DNA ladder electrophoresis revealed that a subclone derived from U937 and carrying a PKR antisense expression vector was resistant to TNF-alpha-induced apoptosis. Further, TNF-alpha initiated a generalized RNA degradation process in which the participation of PKR was required. Finally, the PKR gene is a candidate "death gene" since overexpression of this gene could bring about apoptosis in U937 cells.


Subject(s)
Apoptosis/drug effects , Interferons/pharmacology , Protein Serine-Threonine Kinases/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Cell Survival/drug effects , Enzyme Induction , Humans , Leukemia, Myeloid/metabolism , Leukemia, Myeloid/pathology , RNA, Ribosomal, 18S/metabolism , Tumor Cells, Cultured , Up-Regulation/drug effects , eIF-2 Kinase
19.
Proc Natl Acad Sci U S A ; 96(21): 11860-5, 1999 Oct 12.
Article in English | MEDLINE | ID: mdl-10518541

ABSTRACT

Persistent infections by viruses such as HIV-1 and hepatitis B virus can pose long-term health hazards. Because establishment of persistent infections involves close interactions and adjustments in both host and virus, it would be informative to establish a paradigm with which a normally cytolytic viral infection can be easily converted to persistent infection, so that the different stages in developing persistent infection can be examined. Such a model system is described in this paper. Highly cytolytic encephalomyocarditis virus (EMCV) infection was shifted to persistent infection as a result of repressed expression of the double-stranded RNA-dependent protein kinase (PKR) in the promonocytic U937 cells. Because of the apoptogenic potential of PKR, a deficiency of PKR resulted in a delay in virus-induced apoptosis in EMCV-infected U937 cells, allowing the eventual establishment of persistent EMCV infection in these cells (U9K-AV2). That this was a bona fide persistent infection was demonstrated by the ability of infected cells to propagate as long-term virus-shedding cultures; electron microscopy studies showing presence of intracellular EMCV virions and chromatin condensation; detection of virus-induced chromosomal DNA fragmentation and sustained expression of apoptogenic p53 and IL-1beta converting enzyme; and demonstration of active EMCV transcription by reverse transcription-PCR. In addition, a host-virus coevolution was observed in U9K-AV2 cultures over time: U9K-AV2 cells exhibited slower growth rates, resistance to viral super-infection, and cessation of IFN-alpha synthesis, whereas the infectivity of EMCV was drastically attenuated. Finally, data are presented on the suitability of this model to study establishment of persistent infection by other viruses such as Sendai virus and reovirus.


Subject(s)
Apoptosis , Encephalomyocarditis virus/growth & development , eIF-2 Kinase/physiology , Cell Survival , Cytopathogenic Effect, Viral , Enzyme-Linked Immunosorbent Assay , Humans , Interferons/metabolism , Models, Biological , RNA, Antisense/metabolism , Reoviridae/growth & development , Respirovirus/growth & development , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , U937 Cells , Virus Activation
20.
J Paediatr Child Health ; 40(7): 410-3, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15228576

ABSTRACT

Tolosa-Hunt syndrome is characterized by a dull, persistent pain around the affected eye, ophthalmoplegia and, sometimes, involvement of other cranial nerves passing through the cavernous sinus. Corticosteroid administration is valuable in the treatment and frequently has a dramatic effect. We report a boy with Tolosa-Hunt syndrome who fails to respond to the initial steroid treatment. The role of the MRI in the management of this condition is discussed.


Subject(s)
Glucocorticoids/therapeutic use , Prednisolone/therapeutic use , Tolosa-Hunt Syndrome/drug therapy , Child , Humans , Magnetic Resonance Imaging , Male , Tolosa-Hunt Syndrome/diagnosis , Tolosa-Hunt Syndrome/physiopathology , Treatment Outcome
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