Choroidal telangiectasia in a patient with hereditary hemorrhagic telangiectasia.
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Aged↗
Biomedical subjects
J H Liu
Publications and source records attributed to J H Liu.
Comparative genomic hybridization of esophageal squamous cell carcinoma: correlations between chromosomal aberrations and disease progression/prognosis.
BACKGROUND: Esophageal carcinoma is a major cause of cancer-related deaths among males in Taiwan. However, to date, the genetic alterations that accompany this lethal disease are not understood. METHODS: Chromosomal aberrations of 46 samples of esophageal squamous cell carcinoma (EC-SCC) were analyzed by comparative genomic hybridization (CGH), and their correlations with pathologic staging and prognosis were analyzed statistically. RESULTS: In total, 321 gains and 252 losses were found in 46 tumor samples; thus, the average gains and losses per patient were 6.98 and 5.47, respectively. Frequent gain abnormalities were found on chromosome arms 1q, 2q, 3q, 5p, 7p, 7q, 8q, 11q, 12p, 12q, 14q, 17q, 20q, and Xq. Frequent deletions were found on chromosome arms 1p, 3p, 4p, 5q, 8p, 9p, 9q, 11q, 13q, 16p, 17p, 18q, 19p, and 19q. It was found that deletions of 4p and 13q12-q14 and gain of 5p were significantly correlated with pathologic staging. Losses of 8p22-pter and 9p also were found more frequently in patients with advanced disease. Gain of 8q24-qter was seen more frequently in patients with Grade 3 tumors. A univariate analysis found that pathologic staging; gains of 5p and 7q; and deletions of 4p, 9p, and 11q were significant prognostic factors. However, pathologic staging became the only significant factor in a multivariate analysis. CONCLUSIONS: CGH not only revealed novel chromosomal aberrations in EC-SCC, but also found possible genotypic changes associated with disease progression. Despite all of the possible associations of chromosomal aberrations with disease progression, the most important prognostic factor for patients with EC-SCC was pathologic staging.
Adult↗
Crystallization and preliminary X-ray diffraction analysis of cytotoxic ribonucleases from bullfrog Rana catesbeiana.
RC-RNases are ribonucleases from Rana catesbeiana oocytes with pyrimidine-guanine sequence specificity. They also possess cell cytotoxicity and lectin activity. Protein crystals of three RC-RNase isozymes, RC-RNase 3, RC-RNase 4 and RC-RNase 6, were grown in various crystal systems under different conditions. Crystals of RC-RNase3 belong to the orthorhombic C222(1) space group, with unit-cell parameters a = 66.66, b = 97.38, c = 85.74 A. Crystals of RC-RNase 4 belong to the trigonal space group P3(1) or P3(2), with unit-cell parameters a = b = 32.22, c = 92.12 A. Crystals of RC-RNase 6 complexed with cytidylyl 2'-5' guanosine belong to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, with unit-cell parameters a = b = 61.80, c = 65.96 A.
Amphibian Proteins↗
Up-regulation of Fas ligand expression by human cytomegalovirus immediate-early gene product 2: a novel mechanism in cytomegalovirus-induced apoptosis in human retina.
Human CMV (HCMV) is an important pathogen that causes widespread diseases in immunocompromised individuals. Among the opportunistic HCMV infections, HCMV retinitis is most common in transplant recipients and AIDS patients. It often leads to blindness if left untreated. The question as to how HCMV infection causes retinal pathogenesis remains unresolved. Here, we report that viral immediate-early gene product 2 (IE2), but not IE1, up-regulates the Fas ligand (FasL) expression in HCMV-infected human retinal pigment epithelium cells. Increased secretion of FasL from virally infected cells into cultured medium was observed upon HCMV infection. The capability of such cell-free medium to induce apoptosis of Fas (CD95)-expressing Jurkat cells further implies that Fas-FasL interaction might mediate cell death in the lesion of HCMV retinitis. To support this idea, we observed augmented soluble FasL levels in vitreous from AIDS patients with HCMV retinitis as compared with that from AIDS patients without HCMV infection. In addition, by in situ hybridization and immunohistochemistry, we detected enhanced signals of FasL, the existence of viral IE Ags and apoptotic cells at the same sites in the lesion of HCMV-infected retina. These results strongly suggest that IE2 induction of FasL expression in human retina might be an important event that takes place in the early stage of infection and finally leads to visual loss in individuals affiliated with HCMV retinitis.
AIDS-Related Opportunistic Infections↗
Crystal structure of the human CD4 N-terminal two-domain fragment complexed to a class II MHC molecule.
The structural basis of the interaction between the CD4 coreceptor and a class II major histocompatibility complex (MHC) is described. The crystal structure of a complex containing the human CD4 N-terminal two-domain fragment and the murine I-A(k) class II MHC molecule with associated peptide (pMHCII) shows that only the "top corner" of the CD4 molecule directly contacts pMHCII. The CD4 Phe-43 side chain extends into a hydrophobic concavity formed by MHC residues from both alpha 2 and beta 2 domains. A ternary model of the CD4-pMHCII-T-cell receptor (TCR) reveals that the complex appears V-shaped with the membrane-proximal pMHCII at the apex. This configuration excludes a direct TCR-CD4 interaction and suggests how TCR and CD4 signaling is coordinated around the antigenic pMHCII complex. Human CD4 binds to HIV gp120 in a manner strikingly similar to the way in which CD4 interacts with pMHCII. Additional contacts between gp120 and CD4 give the CD4-gp120 complex a greater affinity. Thus, ligation of the viral envelope glycoprotein to CD4 occludes the pMHCII-binding site on CD4, contributing to immunodeficiency.
Amino Acid Sequence↗
[Relationship between serum thyroid hormone and GH-IGF axis, growth failure in nephrotic rats].
OBJECTIVE: To investigate the individual effects of malnutrition, nephrosis and glucocorticoid therapy on serum thyroid hormone, and explore the relationship between serum thyroid hormone and GH-IGF axis, growth failure in nephrotic rats. METHODS: Twenty-four male Sprague-Dawley (SD) rats were randomly divided into control group, pair-fed group, doxorubincin-induced nephrotic group (nephrotic group) and dexamethasone-treated nephrotic group (des-treated group). Serum T3/T4, GH and IGF-I were measured by RIA, serum IGFBPs were measured by Western ligand blot, liver GHR and IGF-I/IGFBPs mRNA were analyzed by radio-receptor assay and RT-PCR respectively. RESULTS: 1. Serum thyroid hormone was low in pair-fed group, lower in nephrotic group and lowest in des-treated group except for high serum T4 in pair-fed group. 2. Serum thyroid hormone was positively related with liver GHR, IGF-I/IGFBP-3 mRNA and serum IGF-I/IGFBP-3, and negatively related with serum IGFBP-2. 3. Serum thyroid hormone was positively related with nose-tail length and weight (both P < 0.01). CONCLUSIONS: The hypothyroidism is a possible mechanism of reducing serum IGF-I levels and biologic action, and resulting in growth failure in nephrotic syndrome.
Animals↗
Human myoblast fusion requires expression of functional inward rectifier Kir2.1 channels.
Myoblast fusion is essential to skeletal muscle development and repair. We have demonstrated previously that human myoblasts hyperpolarize, before fusion, through the sequential expression of two K+ channels: an ether-à-go-go and an inward rectifier. This hyperpolarization is a prerequisite for fusion, as it sets the resting membrane potential in a range at which Ca2+ can enter myoblasts and thereby trigger fusion via a window current through alpha1H T channels.
Antisense Elements (Genetics)↗
Posttonsillectomy hemorrhage: what is it and what should be recorded?
OBJECTIVES: To report on our incidence of posttonsillectomy hemorrhage and to define what constituted posttonsillectomy bleeding. DESIGN: Retrospective study. SETTING: Tertiary care children's hospital and a local satellite facility. PATIENTS: A series of 1438 consecutive patients who had undergone either tonsillectomy or adenotonsillectomy between January 1, 1999, and December 31, 1999. INTERVENTION: During this period, parents were instructed to return with their children for clinical evaluation if any blood was seen in the postoperative period. MAIN OUTCOME MEASURES: Postoperative day of evaluation, age, sex, location of bleeding, management strategy, length of hospital admission, and any bleeding disorders were noted for each patient. RESULTS: A total of 112 patients underwent evaluation 134 times. Of these patients, 96 required only 1 evaluation and 16 required more than 1 evaluation. All patients who had more than 1 evaluation required intervention. The total number of children requiring intervention for posttonsillectomy hemorrhage was 51 (3.5%) of the 1438 patients. Female patients were more likely than male patients to return for evaluation. Patients who were 12 years and older were the most likely and those 3 years and younger were the least likely to have posttonsillectomy hemorrhage. The most common time from surgery to initial evaluation for hemorrhage was 6 days. CONCLUSIONS: By reviewing our own criteria for defining and recording posttonsillectomy hemorrhage, we conclude that posttonsillectomy hemorrhage is defined differently in the literature. This supports the need for a standard definition to allow for direct comparisons.
Adenoidectomy↗
Carcinoembryonic antigen in monitoring of response to systemic chemotherapy in patients with metastatic colorectal cancer.
The response to chemotherapy of solid tumors is generally assessed by measuring tumors visualized by imaging. However, the response assessment based on imaging is not always feasible because patients often have disease not measurable by imaging, such as diffuse peritoneal dissemination. We evaluated the correlation between the change on imaging and change in CEA levels for assessing chemotherapeutic response of patients with metastatic colorectal cancer. Between July 1993 and August 1999 we retrospectively examined 136 patients with metastatic colorectal carcinoma, all of whom had measurable lesions. Forty patients received oral tegafur-uracil (300 mg/m2/day) plus folinic acid (60 mg/day) for 4 weeks, repeated every 5 weeks, as the firstline treatment. Another 96 patients received either a weekly intravenous bolus injection of 5-fluorouracil (400 mg/m2) plus folinic acid (20 mg/m2), or an intravenous bolus injection of 5-fluorouracil (425 mg/m2) plus folinic acid (20 mg/m2) for 5 consecutive days every month. Responders, based on CEA assessment, were defined as those with a greater than 50% drop in CEA level for more than 4 weeks. The pretreatment CEA levels were elevated beyond the normal cutoff value in 110 (81%) patients. A response rate of 18.4% (95% CI, 11.9-24.9%), including 8 complete remissions and 17 partial remissions, was achieved according to imaging studies. The response rate assessed by CEA was 25% (34/136). Sixteen responders (47%) based on CEA had no remission on imaging. The sensitivity of change in CEA levels in the prediction of true responders and progressive diseases on imaging were 72% and 81%, respectively. In terms of the positive predictive value, change in CEA levels in the prediction of true responders and progressive disease on imaging were 53% and 85%, respectively. Patients with remarkable falls on CEA levels survived significantly longer than nonresponders (P < 0.001, log-rank test). At follow-up of 48 months the median survival for responders and nonresponders assessed by CEA was 28 months and 13 months, respectively. These data suggest that measurement of CEA levels might be helpful in monitoring chemotherapeutic response when imaging study is unsuitable for assessing the response in clinical practice. Furthermore, measurement of CEA levels may be helpful in determining the prognosis of patients with metastatic colorectal cancer receiving chemotherapy.
Adult↗
Tamoxifen and colchicine-modulated vinblastine followed by 5-fluorouracil in advanced renal cell carcinoma: a phase II study.
OBJECTIVES: Chemotherapy resistance of renal cell carcinoma (RCC) has been attributed in large part to multidrug resistance (MDR). Reported MDR-modulated chemotherapy for RCC, however, has resulted in only marginal response benefits. In this study, the MDR-modulated effect of paired tamoxifen and colchicine on vinblastine and the possible additive effect of 5-fluorouracil (5-FU) were investigated in the treatment of advanced RCC. METHODS: Chemotherapy was administered every 4 weeks with biweekly vinblastine (4 mg/m(2)/day, intravenously on days 1 and 15) modulated by oral tamoxifen (100 mg/day) and colchicine (1 mg/day) from days -1 to 2 and from days 13 to 16. 5-FU (800 mg/m(2)/day from days 2 to 5) was administered after vinblastine administration as a continuous infusion. RESULTS: Of 17 eligible patients with advanced RCC available for evaluation, 1 achieved a complete response (CR) and 3 a partial response (PR), with an overall response (CR plus PR) rate of 23.5%. The median overall survival time of all patients was 10 months (95% confidence interval [CI] 3.5 to 16.5); that of our patients with poor, intermediate, and favorable risks as stratified by Motzer's model was 6 (95% CI 1.7 to 10.3), 10 (95% CI 7.9 to 12.2), and 26 (95% CI 24.4 to 27.6) months, respectively. These results are encouraging in view of the poor efficacy of chemotherapy in RCC observed previously. Additionally, the treatment toxicity was limited: toxicity of grade 3 or greater occurred in only 1 patient with leukopenia, and no treatment-related mortality was found. CONCLUSIONS: The encouraging response rates and overall survival with limited toxicity warrant further investigation of this combination therapy as an integrated part of immunochemotherapy for RCC.
Adult↗
Color Doppler imaging study of retrobulbar hemodynamics in chronic angle-closure glaucoma.
PURPOSE: To evaluate the retrobulbar hemodynamics in patients with chronic angle-closure glaucoma (CACG) by using color Doppler imaging (CDI) and to correlate the degree of glaucomatous visual field loss with the hemodynamic parameters. DESIGN: Prospective case series. PARTICIPANTS AND CONTROLS: Twenty-six Chinese patients with CACG and 26 age-matched and gender-matched normal subjects were recruited. All CACG patients had history of chronic intraocular pressure (IOP) elevation and asymmetric visual field defects between their fellow eyes. After receiving laser peripheral iridotomy and/or filtration surgery, all of them had bilateral medication-free controlled IOP before enrolling into the study. METHODS: Each subject underwent CDI measurement in the central retinal artery (CRA) and the nasal and temporal short posterior ciliary arteries (PCA). Visual fields of the CACG patients were obtained with Humphrey 24-2 program. The visual field defects were scored with the Advanced Glaucoma Intervention Study (AGIS) system. For each CACG patient, the eye with lower AGIS score was defined as the better eye and the eye with higher score as the worse eye. MAIN OUTCOME MEASURES: Peak-systolic velocity (PSV), end-diastolic velocity (EDV) and resistance index (RI) were determined. RESULTS: The EDV in the CRA and the temporal PCA was decreased significantly (P = 0.041 and 0.023, respectively) in the worse eyes of CACG patients compared with those in the control eyes. The better eyes of CACG patients showed no significant change in hemodynamic parameters compared with the control eyes. While comparing the fellow eyes of CACG patients, the worse eyes had significantly lower EDV in the temporal PCA (P = 0.012) than the contralateral better eyes. In 11 CACG patients with a difference of at least 8 in AGIS visual field scores between their fellow eyes, the worse eyes had significantly lower EDV (P = 0.041) in the CRA and lower PSV (P = 0.018) and EDV (P = 0.018) in the temporal PCA compared with those in the contralateral eyes. In multivariate regression analysis, the AGIS scores were significantly correlated with the PSV in the CRA (P = 0.015) and with the EDV (P < 0.001) and RI (P = 0.027) in the temporal PCA in patients with CACG. CONCLUSIONS: Patients with well-controlled CACG may have decreased retrobulbar blood flow velocities and increased vascular resistance in the CRA and temporal PCA. The degree of retrobulbar hemodynamic impairment was well correlated with the degree of glaucomatous visual field loss.
Aged↗
Visual acuity and contrast sensitivity in different types of posterior capsule opacification.
PURPOSE: To compare the visual acuity (VA) and contrast sensitivity in 2 types of posterior capsule opacification (PCO) in pseudophakic eyes before and after neodymium:YAG (Nd:YAG) capsulotomy and to evaluate vision test results after Nd:YAG capsulotomy. SETTING: Department of Ophthalmology, Taipei Veterans General Hospital, National Yang-Ming University, Taipei, Taiwan. METHODS: Fourteen eyes with fibrosis-type PCO and 15 eyes with Elschnig-pearl-type PCO were enrolled prospectively. Before and 1 week after Nd:YAG capsulotomy, VA and contrast sensitivity were assessed using the illiterate E version of the Bailey-Lovie chart and the Vistech VCTS 6000 chart, respectively. RESULTS: Before capsulotomy, the mean logMAR acuity in the group with Elschnig-pearl-type PCO was 0.47 +/- 0.32 (SD) and in the group with fibrosis-type PCO, 0.17 +/- 0.07. The difference between the 2 groups was significant (P =.002). After capsulotomy, there was no significant between-group difference (P >.05). Before capsulotomy, the contrast sensitivity was significantly worse (P <.01) at all spatial frequencies in the group with pearl-type PCO, especially at 6 cycles per degree. After capsulotomy, there was no significant between-group difference (P >.05) at any spatial frequency. CONCLUSIONS: After cataract surgery, patients with pearl-type PCO had lower VA and contrast sensitivity than those with fibrosis-type PCO. An Nd:YAG capsulotomy improved the VA and contrast sensitivity in patients with both types of PCO.
Aged↗
Efficient non-viral DNA-mediated gene transfer to human primary myoblasts using electroporation.
Gene transfer of human primary myoblasts with various non-viral methods has been hampered by low yield of transfection. We report here an efficient, simple and reproducible non-viral DNA-mediated gene transfer procedure for transfecting human myoblasts. We found that electroporation promotes a highly efficient DNA uptake by human primary cultures of myogenic cells. Under optimal conditions, 60-70% of human myoblasts transfected with the enhanced green fluorescent gene expressed the enhanced green fluorescent protein. Electroporated myoblasts behaved normally as judged by their ability to synthesize and express developmentally regulated proteins and to undergo terminal differentiation, i.e. to fuse and form myotubes. We showed, in addition, that a subpopulation of cultured human myoblasts with self-renewing properties and equivalent to native muscle satellite cells were as efficiently transfected by electroporation as proliferating myoblasts. Thus, the development of gene therapies based on the engineering and transplantation of human myoblasts may greatly benefit from gene transfer by electroporation.
Cell Fusion↗
Quantitative assessment of retinal thickness in diabetic patients with and without clinically significant macular edema using optical coherence tomography.
PURPOSE: To assess patients with diabetic macular edema quantitatively using optical coherence tomography (OCT). METHODS: OCT was performed in 14 eyes with diabetic retinopathy and ophthalmoscopic evidence of clinically significant macular edema (CSME) and in 19 diabetic eyes without CSME. Retinal thickness was computed from the tomograms at fovea and other 36 locations throughout the macula. RESULTS: The mean +/- standard deviation foveal thickness was 255.6 +/- 138.9 microm in eyes with CSME, and 174.6 +/- 38.2 microm in eyes without CSME (p = 0.051). Within 2000 microm of the center of the macula, eyes with CSME had significantly thicker retina in the inferior quadrant than those without CSME (p < 0.01). The foveal thickness was correlated with logMAR visual acuity (gamma = 0.68, p < 0.01). OCT identified sponge-like retinal swelling and/or cystoid macular edema in 11 (58%) eyes without CSME, and in 12 (86%) eyes with CSME. CONCLUSIONS: Criteria of CSME seem to be insufficient in really identifying macular edema. OCT may be more sensitive than a clinical examination in assessing diabetic macular edema and is a quantitative tool for documenting changes in macular thickening.
Diabetic Retinopathy↗
Relapse of Graves' disease after successful allogeneic bone marrow transplantation.
As shown in many reports, allogeneic BMT can help cure autoimmune diseases. Conversely, we present a 24-year-old woman with Graves' disease, which was diagnosed just before BMT for CML. The Graves' disease remitted immediately after BMT but relapsed 18 months later. Since the donor was free from thyroid diseases and the patient showed a rapid shift to complete donor chimerism after BMT, the autoimmune problem seemed neither to arise directly from the donor nor simply from the recipient's residual lymphocytes. On the contrary, it was most likely compounded by chronic GVHD as suggested by the accompanying GVHD symptoms and the absolute donor karyotype in bone marrow cells. A Graves' disease-susceptible HLA allele was also shared between recipient and donor, possibly enhancing the chances of this condition developing. Thus, allogeneic BMT may facilitate relapses in autoimmune diseases as well as alleviating them.
Adult↗
Exogenous vasopressin influences intraocular pressure via the V(1) receptors.
PURPOSE: To compare central, peripheral, and ocular effects of exogenously given vasopressin on intraocular pressure (IOP) and to identify the related receptor mechanisms of action in rabbits. METHODS: Young adult New Zealand albino rabbits were entrained under a daily 12-hour light and 12-hour dark cycle. In the early light period, bolus injections of vasopressin or desmopressin (a specific V(2) receptor agonist) were given either to the central nervous system (CNS) through an implanted cannula to the 3(rd) ventricle or to the systemic circulation via the ear vein in conscious rabbits. Changes in IOP and pupil size were monitored for up to 6 hours and dose-response curves were generated. Effects of centrally and peripherally given vasopressin on IOP were further examined following pretreatments with a selective V(1) receptor antagonist administered into the 3(rd) ventricle and into the ear vein, respectively. In order to clarify whether or not exogenously given vasopressin can alter IOP by mechanisms inside the eye, vasopressin was injected into the anterior chamber or the vitreous chamber unilaterally in conscious rabbits. Changes in IOP and pupil size were monitored. After an anterior chamber or intravitreal injection of the V(1) receptor antagonist, changes in IOP and pupil size due to an intravenous injection of vasopressin were determined to study the involvement of the related receptor mechanism. RESULTS: A dose-dependent elevation of IOP appeared after injections of vasopressin into the 3(rd) ventricle. There was no pupillary change. This IOP elevation was blocked by the pretreatment with the V(1) receptor antagonist. Following intravenous injections of vasopressin, significant reductions of IOP and pupil size occurred. These reductions were blocked by the pretreatment with the V(1) receptor antagonist. Intracerebroventricular or intravenous injection of desmopressin had no effect on IOP or pupil size. Injection of vasopressin into the anterior chamber or the vitreous chamber caused significant reductions of IOP and pupil size. Pretreatment with the V(1) receptor antagonist into the anterior chamber or the vitreous chamber prevented the reductions of IOP and pupil size following an intravenous injection of vasopressin. CONCLUSIONS: Intracerebroventricular and intravenous injections of vasopressin cause opposite effects on IOP. The central effect of vasopressin on IOP and the peripheral effects of vasopressin on IOP and pupil size are due to stimulations of the V(1) receptors. Reductions of IOP and pupil size following intravenous injections of vasopressin are at least partially due to stimulations of the V(1) receptors inside the eye.
Animals↗
Visual impairment in a Taiwanese population: prevalence, causes, and socioeconomic factors.
PURPOSE: We sought to estimate the prevalence of visual impairment among an elderly population in urban Taiwan, determine the causes of visual impairment, and gain information about certain socioeconomic factors associated with visual impairment. METHODS: A population-based survey of ocular diseases in residents aged 50 years or older was conducted in Peitou Precinct, Taipei, Taiwan. All participants underwent a comprehensive ophthalmic examination, including visual acuity measurement, using standardized protocols. Demographic data, marital status, employment status, and educational level were gathered through an interview. RESULTS: A total of 2034 participants completed the visual acuity measurements. The prevalence of visual impairment (defined as best-corrected visual acuity in the better eye <6/18) among this population was 2.75% (95% confidence intervals: 2.04%-3.46%). Three major causes of visual impairment were cataract (30.4%), high myopic macular degeneration (25.0%), and age-related macular degeneration (14.3%). In multivariate analysis, age was positively correlated with visual impairment (P < 0.001), and higher education level was associated with a significant decrease in the odds of being visually impaired (P < 0.001). No relation was found between visual impairment and sex, or marital and employment status. CONCLUSIONS This study provides the first information about the prevalence and causes of visual impairment in Taiwan, and identifies age and educational level as the most important factors related to visual impairment. Additional educational programs should be developed to improve individual awareness of age-related ocular diseases and the availability of current ophthalmic intervention.
Age Distribution↗
Are women occupying positions of power online? Demographics of chat room operators.
Internet statistics indicate a reduction in the gender discrepancy online. Yet, what is the situation within specific online communities like Internet Relay Chat (IRC)? Likewise, what is the gender status of those occupying positions of power online? An exploratory study of chat room operators (those who govern chat rooms) was conducted to investigate gender differences in operator's demographic characteristics and IRC experience. Whether those less satisfied with their real-life occupation were attracted to chat room operator positions was also investigated. A survey of 423 chat room operators was administered, comprising 25% women. Real-life occupations of chat room operators covered a broad spectrum, from professional and managerial to service, sales, and production workers, as well as those not employed. The most common occupational category cited was student, with very similar proportions of men and women occupying high-status positions. Of the occupations listed, 23% fell within the IT industry, with significantly more male than female operators working in this area. Majorities of both genders were satisfied with their real-life occupation. There was no relationship between job satisfaction and IRC experience or time spent as chat room operator. There were no gender differences for IRC experience. Majorities of both genders had been using IRC for 1 to 3 years or more, used IRC daily, and spent most or all of their time on IRC as operators. Ages ranged from 11 to 66 years, with the mean age 25 years. Women were significantly older than men. A significant proportion of men and women were from North America.
Adolescent↗