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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 433 records · Page 24Linked to original sources
PubMed1998

Performance of transcription-mediated amplification and ligase chain reaction assays for detection of chlamydial infection in urogenital samples obtained by invasive and noninvasive methods.

Based on the amplification of chlamydia-specific rRNA sequences and the ligase chain reaction (LCR), the performance characteristics of the Gen-Probe Chlamydia trachomatis transcription-mediated amplification (TMA) assay were evaluated with endocervical, urine, and vulval specimens from women and urethral and urine specimens from men and were compared with those for cultures on endocervical, vulval, and urethral swabs. Of the 308 women and 240 men tested, 25 (8.1%) and 44 (18.3%), respectively, were shown to be infected. By using the infected individual as the expanded "gold standard" for calculations, the TMA assay and LCR gave similar performances for the sensitivity of male urethral (93.2%) and urine (88.6 and 86.4%) samples, while culture detected only half of the 44 infected men. In women, the sensitivities of the TMA assay for endocervical and vulval samples were 88 and 92%, respectively, compared to values of 92% for the LCR on both sample types and of 52 and 8%, respectively, for culture. By using first-void urine for chlamydial diagnosis in women, LCR detected 24 (96%) and TMA assay detected 19 (76%) infected individuals, showing a significantly lower sensitivity for urine in women (P = 0.0253). The results indicate a high overall agreement for both amplifying techniques for all examined specimen types, except for female urine. Furthermore, they confirm the previous observation that vulval swabs are an effective alternative noninvasive sample type for the detection of C. trachomatis infection in women by nucleic acid-based amplification technologies.

Cervix Uteri↗
PubMed1998

Mutation of the Lck-binding motif of Tip enhances lymphoid cell activation by herpesvirus saimiri.

The proline-rich SH3-binding (SH3B) motif of the tyrosine kinase-interacting protein (Tip) of herpesvirus saimiri (HVS) is required for binding to the cellular Src family kinase Lck. We constructed a mutant form of HVS in which prolines in the SH3B motif of Tip were altered to alanines. This mutant form of Tip was incapable of binding to Lck. The mutant virus, HVS/Tip mSH3B, retained its ability to immortalize common marmoset lymphocytes in culture. In fact, common marmoset lymphocytes immortalized by the HVS/Tip mSH3B mutant displayed increased expression of HLA-DR lymphocyte activation marker, an altered pattern of tyrosine phosphorylation, increased expression of the tyrosine kinase Lyn, and a shift in electrophoretic mobility of Lck compared to cells immortalized by wild-type HVS. Experimental infection of common marmosets resulted in fulminant lymphoma with both HVS/Tip mSH3B and wild-type HVS. However, HVS/Tip mSH3B produced greater infiltration of affected organs by proliferating lymphoid cells compared to wild-type HVS. These results demonstrate that Tip binding to Lck is not necessary for transformation and that abrogation of Tip binding to Lck alters the characteristics of transformed cells and the severity of the pathologic lesions.

Animals↗
PubMed1998

Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor.

Interferons (IFNs) are a family of multifunctional cytokines with antiviral activities. The K9 open reading frame of Kaposi's sarcoma-associated herpesvirus (KSHV) exhibits significant homology with cellular IFN regulatory factors (IRFs). We have investigated the functional consequence of K9 expression in IFN-mediated signal transduction. Expression of K9 dramatically repressed transcriptional activation induced by IFN-alpha, -beta, and -gamma. Further, it induced transformation of NIH 3T3 cells, resulting in morphologic changes, focus formation, and growth in reduced-serum conditions. The expression of antisense K9 in KSHV-infected BCBL-1 cells consistently increased IFN-mediated transcriptional activation but drastically decreased the expression of certain KSHV genes. Thus, the K9 gene of KSHV encodes the first virus-encoded IRF (v-IRF) which functions as a repressor for cellular IFN-mediated signal transduction. In addition, v-IRF likely plays an important role in regulating KSHV gene expression. These results suggest that KSHV employs an unique mechanism to antagonize IFN-mediated antiviral activity by harboring a functional v-IRF.

3T3 Cells↗
PubMed1998

A role for herpesvirus saimiri orf14 in transformation and persistent infection.

The product of open reading frame 14 (orf14) of herpesvirus saimiri (HVS) exhibits significant homology with mouse mammary tumor virus superantigen. orf14 encodes a 50-kDa secreted glycoprotein, as shown previously (Z. Yao, E. Maraskovsky, M. K. Spriggs, J. I. Cohen, R. J. Armitage, and M. R. Alderson, J. Immunol. 156:3260-3266, 1996). orf14 expressed from recombinant baculovirus powerfully induces proliferation of CD4-positive cells originating from several different species. To study the role of orf14 in transformation, a mutant form of HVS (HVS Deltaorf14) was constructed with a deletion in the orf14 gene. The transforming potential of HVS Deltaorf14 was tested in cell culture and in common marmosets. Parental HVS subgroup C strain 488 immortalized common marmoset T lymphocytes in vitro to interleukin-2-independent growth, while the HVS Deltaorf14 mutant did not produce such a growth transformation. In addition, HVS Deltaorf14 was nononcogenic in common marmosets. In contrast to other nononcogenic HVS mutant viruses which were repeatedly isolated from peripheral blood mononuclear cells of infected marmosets for more than 5 months, HVS Deltaorf14 did not persist at a high level in vivo. These results demonstrate that orf14 of HVS is not required for replication but is required for transformation and for high-level persistence in vivo.

Animals↗
PubMed1998

Identification of an immunoreceptor tyrosine-based activation motif of K1 transforming protein of Kaposi's sarcoma-associated herpesvirus.

Kaposi's sarcoma-associated herpesvirus (KSHV) is consistently identified in Kaposi's sarcoma and body cavity-based lymphoma. KSHV encodes a transforming protein called K1 which is structurally similar to lymphocyte receptors. We have found that a highly conserved region of the cytoplasmic domain of K1 resembles the sequence of immunoreceptor tyrosine-based activation motifs (ITAMs). To demonstrate the signal-transducing activity of K1, we constructed a chimeric protein in which the cytoplasmic tail of the human CD8alpha polypeptide was replaced with that of KSHV K1. Expression of the CD8-K1 chimera in B cells induced cellular tyrosine phosphorylation and intracellular calcium mobilization upon stimulation with an anti-CD8 antibody. Mutational analyses showed that the putative ITAM of K1 was required for its signal-transducing activity. Furthermore, tyrosine residues of the putative ITAM of K1 were phosphorylated upon stimulation, and this allowed subsequent binding of SH2-containing proteins. These results demonstrate that the KSHV transforming protein K1 contains a functional ITAM in its cytoplasmic domain and that it can transduce signals to induce cellular activation.

Amino Acid Sequence↗
PubMed1998

Are there sex differences in neuropsychological functions among patients with schizophrenia?

OBJECTIVE: Studies of sex differences in neuropsychological performance in schizophrenia report inconsistent results, due in part to methodological artifacts. The study presented here was specifically designed to examine sex differences in neuropsychological performance. It was hypothesized that schizophrenic women would exhibit fewer neuropsychological deficits than schizophrenic men and that their performance would be more similar to that of normal women than schizophrenic men's performance would be to that of normal men. METHOD: Thirty-one outpatients with DSM-III-R-defined schizophrenia were systematically sampled from an extensive service network serving a large urban catchment area for seriously mentally ill persons. Twenty-seven normal comparison subjects were matched within sex on the basis of age, parental socioeconomic status, ethnicity, and handedness. An extensive neuropsychological test battery was administered, and multivariate analysis of variance was used to test for the effects of sex and group and sex-by-group interactions. RESULTS: Male patients were significantly impaired across all functions in comparison with normal male subjects and on tests of attention, verbal memory, and executive functions in comparison with female patients. Female patients performed significantly worse than female normal comparison subjects only on tests of attention, executive functions, visual memory, and motor functions. CONCLUSIONS: The findings suggest that women with schizophrenia may be less vulnerable to particular cognitive deficits, especially those involving verbal processing, than schizophrenic men.

Adult↗
PubMed1998

Patient perception of quality of care provided by specialists and generalists.

Efforts to control medical care costs have focused on reducing the number of specialists directing patient care. This cross-sectional survey evaluated multiple sclerosis patient perceptions of the quality of care across three patterns of care: primary care (n = 156), single specialty care (n = 338), and comprehensive care (n = 75). The pattern of medical care received by the patient was defined by: (1) whether the MS provider was a primary care physician or (2) a neurologist; (3) whether the patient reported using other specialty services, such as psychological, rehabilitation, or social work services. Process indicators of quality of care were measured by subscales for interpersonal aspects of care, access to care, and perceived action plan. The MSQOL-54 was used to measure health-related quality of life. Pattern of care was not related to the Interpersonal or Access dimensions of care, after adjusting for health status and sociodemographic characteristics. Patients in the Single Specialty and Comprehensive Care patterns of care were, however, more likely to report their MS provider having and implementing an action plan. We conclude that MS patients who receive Single Specialty and Comprehensive Care are more likely to get diagnostic and treatment-related tests, as well as immunotherapeutic and experimental treatments.

Attitude to Health↗
PubMed1998

Inhibition of urokinase activity by the antiangiogenic factor 16K prolactin: activation of plasminogen activator inhibitor 1 expression.

The N-terminal fragment of PRL (16K PRL) is an antiangiogenic factor that, in vitro, inhibits several components of angiogenesis including basic fibroblast growth factor (bFGF)-induced cell division, migration, and organization of capillary endothelial cells. An essential step in the regulation of angiogenesis is the activation of urokinase (urokinase type plasminogen activator, uPA), which in turn activates a cascade of proteases that play essential roles in endothelial cell migration and tissue remodeling. Treatment of bovine capillary endothelial cells (BBEC) with 16K PRL inhibited bFGF-stimulated urokinase activity in BBEC as detected by plasminogen substrate gel assay. 16K PRL did not appear to be acting via an effect on uPA expression because no change in messenger RNA levels were observed. However, protein levels of plasminogen activator inhibitor-1 (PAI-1), a specific inhibitor of urokinase, were increased by 16K PRL independent of the action of bFGF. The 16K PRL-induced increase in PAI-1 protein levels appear to be the result of increased expression of the PAI-1 gene. Increased production of PAI-1 induced by 16K PRL results in the formation of inactive PAI-1/uPA complexes, consistent with the observed decrease in uPA activity.

Animals↗
PubMed1998

Does a screening questionnaire for essential tremor agree with the physician's examination?

In research studies of essential tremor (ET), monetary and geographic factors often necessitate diagnosis by interview rather than by examination. Few attempts have been made to determine the validity of a screening instrument for ET. A total of 242 subjects (33 definite or probable ET, 54 possible ET, and 155 normal) were part of a community-based family study of ET in northern Manhattan. Subjects underwent a tremor interview and videotaped tremor examination. The interview included 12 screening questions for ET. Two neurologists rated the severity of tremor on videotape and assigned diagnoses. The subjects' responses to the 12 screening questions were compared with the neurologic examination and the neurologists' diagnoses. There was an association between the number of affirmative responses on the 12-item screen and the severity of tremor during the videotaped tremor examination (r = 0.66, p < 0.01). Including those with probable and definite ET and defining a positive screen result as an affirmative response to at least 1 of 12 screening questions, the sensitivity of the screening questionnaire was 73%, the specificity was 96%, and the positive predictive value was 80%. The responses to the questionnaire closely correlated with the severity of tremor on neurologic examination. The questionnaire had moderate validity for subjects with probable or definite ET; subjects with mild ET often screened negative. Hence, in population-based studies and family studies of ET, it is important to examine all subjects for the presence of mild asymptomatic ET.

Adolescent↗
PubMed1998

The surgical technique of the Fobi-Pouch operation for obesity (the transected silastic vertical gastric bypass).

The Fobi-Pouch operation (FPO) for obesity is the product of clinical trials, more than 15 years of personal clinical experience and information gathered from publications, scientific meetings, and personal communications with other bariatric surgeons. The essence of the operation is the small vertical pouch (< 25 ml), an externally supported stoma, the interposed Roux-en-Y limb, the gastrostomy and the bypassed stomach marker to facilitate percutaneous transabdominal access to the bypassed segment. Patients undergoing this operation are usually given bowel prep the day before the operation, admitted the morning of the operation and started on subcutaneous heparin, prophylactic antibiotic and hydration. Antithrombotic sequential compression devices are regularly used. The hospital stay is usually 4 days. Our results and those of other surgeons who have used this modification substantiate the rationale for the modifications entailed in the FPO. Our longer-term experience and results are being compiled for publication.

Anastomosis, Roux-en-Y↗
PubMed1998

Access to the bypassed stomach after gastric bypass.

The gastric bypass (GBP) Operation is progressively being widely used to treat severe obesity. One problem with this operation is that it leaves the bypassed segment of the gastrointestinal tract not readily available for either mechanical, radiological or endoscopic evaluation. We have addressed this problem by putting a gastrostomy tube in the bypassed stomach at the time of the GBP. A radio-opaque marker placed around the gastrostomy site enables easy radiological localization of and thus easy percutaneous access to the bypassed stomach. The surgical technique is presented.

Gastric Bypass↗
PubMed1998

Assessment of depression in a population at risk ... newly admitted nursing home residents.

Depression in newly admitted nursing home residents is a frequently overlooked area of nursing concern. Educating staff to systematically use a standardized depression assessment protocol with all newly admitted residents would facilitate efforts to enhance the quality of residents' lives by identifying depression so that prompt treatment is possible. Other previously admitted residents who appear to be particularly vulnerable to depression would also benefit from this assessment. The use of this protocol for the assessment of depression offers the possibility of providing more accurate and more comprehensive information regarding mood states than that currently being documented in the Minimum Data Set.

Aged↗
PubMed1998

Medical counseling through computer communication networks.

Medical counseling on the computer communication network will be used increasingly with wide-ranging concern of people about health and strengthening the role of medical care as social service. This study was designed to explore main problems/issues of network counseling and to suggest future prosperity of medical counseling. We analyzed questions and answers in the Association of Family Medicine in the KETEL since 1991, Medical counseling corner which is in the UNITEL since 1996, and Online counseling in VIRTUAL HOSPITAL since 1996, and classified the reason for encounter, systematic classification of counseling by ICPC, and answer content. Inquiry about symptoms was the most common reason for encounter, followed by treatment and prevention strategies, detailed information about diseases, and inquiry about laboratory tests. Systematic classification by ICPC showed common problems of skin, digestive, musculoskeletal and general & unspecified, which was a different look compared with common problems in primary care. The answer content presented a different look among three groups. Common answers were mainly to offer medical information, to recommend visiting a doctor, and to provide self-care remedies. Network counselling will supplement the incompleteness of medical interview with doctors, and make it easy to communicate various pieces of information between patients and doctors.

Computer Communication Networks↗
PubMed1998

Molecular analysis of rifampin-resistant Mycobacterium tuberculosis isolated from Korea by polymerase chain reaction-single strand conformation polymorphism sequence analysis.

OBJECTIVE: To assess the molecular mechanism of rifampin (RMP) resistance in clinical strains of Mycobacterium tuberculosis. DESIGN: The molecular nature of a part of the rpoB gene in 77 M. tuberculosis clinical strains isolated in Korea was analyzed using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and PCR-sequence analysis. RESULTS: Among 67 RMP-resistant isolates, 50 showed SSCP profiles different from that of an RMP-sensitive control strain, M. tuberculosis H37Rv, indicating the possible existence of a sequence alteration in this region of the rpoB gene, while 17 resistant isolates displayed SSCP profiles indistinguishable from that of the sensitive control strain. Subsequently, 17 clinical isolates whose SSCP profiles were difficult to distinguish from the control strain were subjected to sequence analysis. The analysis revealed that all 17 isolates did indeed contain mutations in the 81 bp region of the rpoB gene, which is associated with RMP resistance. CONCLUSION: The results from our study clearly indicate that the molecular mechanism of RMP resistance in M. tuberculosis isolates from Korea involves alterations in the rpoB gene. In addition, this study suggests that PCR-direct sequence analysis works more efficiently and accurately than PCR-SSCP analysis for rapid screening of RMP-resistant M. tuberculosis clinical isolates.

Antibiotics, Antitubercular↗
PubMed1998

Signaling mechanisms and molecular characteristics of G protein-coupled receptors for lysophosphatidic acid and sphingosine 1-phosphate.

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are potent phospholipid mediators with diverse biological activities. Their appearance and functional properties suggest possible roles in development, wound healing, and tissue regeneration. The growth-stimulating and other complex biological activities of LPA and S1P are attributable in part to the activation of multiple G protein-mediated intracellular signaling pathways. Several heterotrimeric G proteins, as well as Ras- and Rho-dependent pathways play central roles in the cellular responses to LPA and S1P. Recently, several G protein-coupled receptors encoded by a family of endothelial differentiation genes (edg) have been shown to bind LPA or S1P and transduce responses of cAMP, Ca2+, MAP kinases, Rho, and gene transcription. This review summarizes our current understanding of signaling pathways critical for cellular responses to LPA and S1P and of recent progress in the molecular biological analyses of the Edg receptors.

Amino Acid Sequence↗
PubMed1997

cAMP-dependent protein kinase inhibits the mitogenic action of vascular endothelial growth factor and fibroblast growth factor in capillary endothelial cells by blocking Raf activation.

Proliferation of endothelial cells is regulated by angiogenic and antiangiogenic factors whose actions are mediated by complex interactions of multiple signaling pathways. Both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) stimulate cell proliferation and activate the mitogen-activated protein kinase (MAPK) cascade in bovine brain capillary endothelial (BBE) cells. We have extended these findings to show that both mitogens activate MAPK via stimulation of Raf-3. Activation of Raf/MAPK is inhibited by increasing intracellular cAMP levels pharmacologically or via stimulation of endogenously expressed beta-adrenergic receptors. Both VEGF- and bFGF-induced Raf-1 activity are blocked in the presence of forskolin or 8-bromo-cAMP by 80%. The actions of increased cAMP appear to be mediated by cAMP-dependent protein kinase (PKA), since treatment with H-89, a the specific inhibitor of PKA, reversed the inhibitory effect of elevated cAMP levels on mitogen-induced cell proliferation and Raf/MAPK activation. Moreover, elevations in cAMP/PKA activity inhibit mitogen-induced cell proliferation. These findings demonstrate, in cultured endothelial cells, that the cAMP/PKA signaling pathway is potentially an important physiological inhibitor of mitogen activation of the MAPK cascade and cell proliferation.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Mutagenicity and polycyclic aromatic hydrocarbon content of fumes from heated cooking oils produced in Taiwan.

According to epidemiologic studies, exposure of women to fumes from cooking oils appears to be an important risk factor for lung cancer. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and analyzed for mutagenicity in the Salmonella/microsome assay. Polycyclic aromatic hydrocarbons were extracted from the samples and identified by HPLC chromatography. Extracts from three cooking oil fumes were found to be mutagenic in the presence of S9 mix. All samples contained dibenz[a,h]anthracene (DB[a,h]A) and benz[a]anthracene (B[a]A). Concentration of DB[a,h]A and B[a]A were 1.9 and 2.2 micrograms/m3 in fumes from lard oil, 2.1 and 2.3 micrograms/m3 in soybean oil, 1.8 and 1.3 micrograms/m3 in peanut oil, respectively. Benzo[a]pyrene (B[a]P) was identified in fume samples of soybean and peanut oil, in concentrations of 19.6 and 18.3 micrograms/m3, in this order. These results provide experimental evidence and support the findings of epidemiologic observations, in which women exposed to the emitted fumes of cooking oils are at increased risk of contracting lung cancer.

Adenocarcinoma↗