Search PubMed⌕ Search

Biomedical subjects

M Y Chen

Publications and source records attributed to M Y Chen.

At least 37 records · Page 2Linked to original sources
PubMed2002

Successful discontinuation of fluconazole as secondary prophylaxis for cryptococcosis in AIDS patients responding to highly active antiretroviral therapy.

Seven AIDS patients with disseminated cryptococcosis who had had immune reconstitution following highly active antiretroviral therapy (HAART) had discontinued their secondary antifungal prophylaxis to prevent relapse of Cryptococcus neoformans infection. The median CD4+ count was 236 cells/ micro L (range, 117-404 cells/ micro L; mean, 247 cells/ micro L) and the plasma viral loads were undetectable in five patients at discontinuation of antifungal prophylaxis. No relapse of cryptococcosis was detected in these patients after a median observation duration of nine months (range, 5.5-4.1 months, mean, 14.6 months) following discontinuation. Our data and review of the literature suggest that discontinuation of fluconazole prophylaxis is safe in patients with reconstitution of immunity following#10; initiation of HAART.

AIDS-Related Opportunistic Infections↗
PubMed2001

Kinetics of antigen-induced phenotypic and functional maturation of human monocyte-derived dendritic cells.

Dendritic cells (DCs), a critical component of innate immunity, are the most potent APCs. When DCs mature, they can elicit strong T cell responses. We studied the kinetics of Ag-induced phenotypic and functional maturation of human monocyte-derived DCs using an in vitro T cell-independent culture system. With this model, we herein show that an Ag that has recently or repetitively been exposed ("exposed Ag") rapidly induces a high level of maturation; however, an Ag that has never or only remotely been exposed ("unexposed Ag") slowly induces a low level of maturation. The kinetics of Ag-induced maturation of DCs possibly implies a novel mechanism for immunological memory that would provide maximal host protection from repetitively invading pathogens in the environment.

Antigens, CD↗
PubMed2001

Association between cytomegalovirus-specific reactivity of T cell subsets and development of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome.

The association between cytomegalovirus (CMV)-specific reactivity of T cell subsets and development of CMV retinitis (CMV-R) was prospectively studied in 50 CMV-seropositive AIDS patients. The frequency of CMV-specific CD69 expression on CD8 T cells was similar in patients with and patients without CMV-R (median, 1.0% vs. 1.2%; P=.14). However, the frequency of CMV-specific CD69 expression on CD4 T cells was significantly lower in patients with CMV-R than in those without CMV-R (median, 0.4% vs. 2.25%; P<.001). CMV-specific CD4 T cell reactivity in patients who developed CMV-R shortly after starting highly active antiretroviral therapy (HAART) remained low, although the CD4 cell counts increased markedly. Therefore, development of CMV-R is associated with a poor CMV-specific reactivity of CD4 T cells but not with poor reactivity of CD8 T cells. Development of CMV-R after initiation of HAART is associated with a poor reconstitution of CMV-specific immune response, rather than with immune rebound.

AIDS-Related Opportunistic Infections↗
PubMed2001

Reconstituted immunity against persistent parvovirus B19 infection in a patient with acquired immunodeficiency syndrome after highly active antiretroviral therapy.

We discovered a patient with AIDS with persistent B19 infection who had slow resolution of anemia after he commenced receiving HAART without intravenous immunoglobulin. The patient's anemia recurred when the initial course of HAART failed, but it remitted slowly after salvage therapy was instituted. However, circulating B19 was still detectable by nested polymerase chain reaction 1 year after commencement of salvage therapy. Immunoglobulin G and immunoglobulin M antibodies against B19 were not detected by means of enzyme-linked immunosorbent assay when the anemia initially resolved, but they were detected after the patient commenced receiving salvage therapy. The absence of antibody response after the initial remission of parvovirus B19 infection suggested that cellular immunity was an important component of reconstituted immune function against B19 after the patient received HAART. The humoral response that was restored later was abnormal; it had strong reactivity to nonstructural protein NS-1 and poor generation of neutralizing antibodies against linear epitopes unique to minor capsid protein VP1.

AIDS-Related Opportunistic Infections↗
PubMed2001

Reciprocal regulatory interaction between human herpesvirus 8 and human immunodeficiency virus type 1.

Human herpesvirus 8 (HHV8) is the primary viral etiologic agent in Kaposi's sarcoma (KS). However, individuals dually infected with both HHV8 and human immunodeficiency virus type 1 (HIV-1) show an enhanced prevalence of KS when compared with those singularly infected with HHV8. Host immune suppression conferred by HIV infection cannot wholly explain this increased presentation of KS. To better understand how HHV8 and HIV-1 might interact directly in the pathogenesis of KS, we queried for potential regulatory interactions between the two viruses. Here, we report that HHV8 and HIV-1 reciprocally up-regulate the gene expression of each other. We found that the KIE2 immediate-early gene product of HHV8 interacted synergistically with Tat in activating expression from the HIV-1 long terminal repeat. On the other hand, HIV-1 encoded Tat and Vpr proteins increased intracellular HHV8-specific expression. These results provide molecular insights correlating coinfection with HHV8 and HIV-1 with an unusually high incidence of KS.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Heparin coinfusion during convection-enhanced delivery (CED) increases the distribution of the glial-derived neurotrophic factor (GDNF) ligand family in rat striatum and enhances the pharmacological activity of neurturin.

Convection-enhanced delivery (CED) distributes macromolecules in the brain in a homogeneous, targeted fashion in clinically useful volumes. However, the binding of growth factors to heparin-binding sites in the extracellular matrix may limit the volume of distribution (V(d)). To overcome this limitation, we examined the effects of heparin coinfusion on V(d) of glial-derived neurotrophic factor (GDNF), neurturin (NTN), artemin, and a nonspecifically bound protein, albumin. Heparin coinfusion significantly enhanced the V(d) of GDNF and GDNF-homologous trophic factors, probably by binding and blocking heparin-binding sites in the extracellular matrix. Furthermore, coinfusion of heparin with NTN enhanced striatal dopamine metabolism, compared to trophic factor administered alone. The negligible benefit of GDNF in recent clinical trials of Parkinson's disease may result from limited tissue distribution. Heparin coinfusion during CED targeting the striatum may alleviate this important limitation. This study demonstrates the influence of receptor binding on the distribution of trophic factors in the CNS.

Animals↗
PubMed2001

Coronary artery calcium quantification with retrospectively gated helical CT: protocols and techniques.

Current generation Helical Computed Tomography, when coupled with cardiac gating can be used to measure coronary vascular calcium. In this article we review the development of retrospectively gated helical computed tomography on a single slice HCT system and its relation to electron beam CT. The impact of heart rate on selection of helical pitch for the creation of a diastolic image set is detailed, as well as, scanning and post-processing techniques are discussed. The development and initial experience of cardiac gating with multidetector CT systems is presented.

Calcium↗
PubMed2001

Psychometrics of a Chinese translation of the swallowing questionnaire.

AIMS OF THE STUDY: The purpose of this study was to determine the psychometric properties of a Chinese version of a swallowing questionnaire. BACKGROUND/RATIONALE: Impaired swallowing may lead to serious complications if health care professionals do not accurately assess the problem and promptly intervene. The recognition of symptoms indicative of a swallowing problem is essential for nurses. The swallowing questionnaire could provide nurses with a valid instrument to assess patients' impaired swallowing. DESIGNS/METHODS: Phase I consisted of experts doing the initial translation into Chinese and back-translations of the questionnaire. Five experts then determined content validity of the Chinese version, and 35 bilingual subjects determined equivalence of the Chinese translation and English version. Phase II determined concurrent validity and internal consistency using 113 screened medical patients as subjects. Phase III used 105 screened long-term care subjects to determine construct validity. RESULTS/FINDINGS: In Phase I, rating on the appropriateness of items on the Chinese version yielding a content validity index of 0.988. The coefficient of equivalence between the Chinese and English versions of the instrument was 0.81, while per cent agreement for all items on the two versions ranged from 0.80--1.00. Phase II established internal consistency with a K-R20 of 0.74, and concurrent validity yielded a correlation between the swallowing questionnaire and the neurological swallowing exam of 0.675 (P < 0.01). Phase III determined construct validity with significant positive correlations found between the swallowing questionnaire and stroke history and masticatory ability. Significant negative correlations were found between swallowing and cognitive status, functional status and albumin. CONCLUSIONS: Although useful as a tool for nursing assessment and intervention, further work on the swallowing questionnaire such as conducting video fluoroscopy and a swallowing speed test, are recommended to further validate its accuracy.

Activities of Daily Living↗
PubMed2001

Increase in B19 viral load prior to relapse of anaemia in an AIDS patient with persistent B19 infection.

Anaemia caused by persistent parvovirus B19 infection can be remitted by intravenous immunoglobulin (IVIG) treatment. However, maintenance IVIG therapy is required in some AIDS patients as well as patients with combined immuno-deficiency because of relapse of anaemia. We used a simple semi-quantitative polymerase chain reaction (PCR) method to trace plasma B19 viral load after administration of IVIG. We noted that the rebound of B19 viral load occurred 6 weeks prior to detection of anaemia. This method may be helpful in determining the interval of maintenance IVIG therapy.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Amebic liver abscess and human immunodeficiency virus infection: a report of three cases.

Invasive amebiasis rarely occurs in homosexual men and human immunodeficiency virus (HIV)-infected individuals and has not been regarded as a beacon for concomitant HIV infection. We encountered a bisexual man with a protracted course of amebic liver abscess and amebic colitis. In the presence of fever, generalized lymphadenopathy, and elevated serum aminotransferase levels, HIV infection was suspected and then confirmed by a de novo seroconversion of HIV antibody. Subsequently, we noted two consecutive patients with amebic liver abscess, also later found to be infected with HIV. The ameba obtained from these three cases was identified as Entamoeba histolytica by amplification of 16S ribosomal RNA by polymerase chain reaction and direct sequencing. This observation suggests that amebic liver abscess and colitis can be presentations for HIV infection in the Far East. Thus, the local patients with invasive amebiasis, especially those with a protracted course or with risk factors of HIV infection, should be tested for HIV.

AIDS-Related Opportunistic Infections↗
PubMed2001

Role of angiography in the detection of aortic branch vessel injury after blunt thoracic trauma.

PURPOSE: The occurrence of aortic arch branch vessel injury as an isolated occurrence or in association with aortic injury after blunt chest trauma has not been emphasized in the literature. The imaging evaluation is also controversial. METHODS: We reviewed thoracic aortograms of 166 patients examined at our institution from May 1995 to May 1999 performed after blunt thoracic trauma. We evaluated the aortograms for aortic and arch branch vessel injuries. Twenty-four injuries were detected and all patients had either a wide mediastinum demonstrated on plain radiographs (22 patients) or mechanism of injury conducive to aortic injury. RESULTS: Of the 166 patients, 24 (14%; 16 men, 8 women; mean age, 50 years) had aortic or arch branch vessel injuries. Isolated aortic injury occurred in 15 (9%) of 166 patients. Branch vessel injury occurred in 9 (5%) of 166 patients; seven patients (10 branch vessels) had isolated branch vessel injury and two patients (three branch vessels) had branch vessel injury associated with aortic injury. The injured branch vessels were brachiocephalic artery (four), left common carotid artery (four), left subclavian artery (three), right internal mammary artery (one), and left vertebral artery (one). The types of branch vessel injuries included intimal tears (nine vessels; 69%), and transection causing a pseudoaneurysm (four vessels; 31%). Revised Trauma Scores in patients with branch vessel injuries were 12 in seven patients and 11 and 4 in one each. CONCLUSION: We emphasize the angiographic findings in these patients that can at times be quite subtle. Awareness of the incidence of such injuries either in isolation or associated with aortic injury has implications regarding evaluation of this patient population with less invasive techniques such as CT or transesophageal echocardiography.

Adolescent↗
PubMed2001

Post-exposure prophylaxis for human immunodeficiency virus: knowledge and experience of junior doctors.

OBJECTIVE: To assess the level of knowledge and experience of post-exposure prophylaxis (PEP) against human immunodeficiency virus (HIV) among junior doctors. METHODS: A questionnaire was sent to all junior doctors working in two major teaching hospitals in London. RESULTS: Most junior doctors had heard of PEP (93%) but fewer were aware that it reduced the rate of HIV transmission (76%). Only a minority of doctors (8%) could name the drugs recommended in recent national guidelines and a significant proportion (43%) could not name any. Almost one third (29%) did not know within what period PEP should be administered. This was despite the fact that the majority of respondents (76%) had experienced high risk exposure to potentially infective material at some stage in their careers and that a significant proportion (18%) had sought advice about PEP following potential exposures. CONCLUSIONS: This study demonstrates that the junior hospital doctors in our survey had inadequate knowledge of PEP against HIV despite being at risk of occupational exposure.

Adult↗
PubMed2001

Intention of residents in internal medicine to care for patients infected with HIV at a university hospital in Taiwan.

The purpose of this study was to investigate internal medicine residents' HIV-related knowledge and their attitudes towards caring for HIV-infected patients, and determine the extent to which these variables influence their care-providing intention. A cross-sectional survey was conducted in 56 internal medicine residents at a university hospital in Taiwan. Results showed residents' lack of sufficient knowledge was reflected by their inaccurate assessment of HIV-associated risk and their tendency to overuse protective gear in unnecessary situations. In general, residents expressed slightly positive attitudes with a neutral intention to care for HIV-infected patients. Knowledge and attitudes were significantly correlated with intention. The use of stepwise regression analysis revealed attitudes accounted for 59% of the variance in intention. Future efforts should focus on designing, implementing, and evaluating educational programmes that address residents' needs to ensure a solid HIV-related knowledge base, support their positive attitudes, address their ambivalent feelings toward providing HIV care, and enhance their intention to care for HIV-infected patients.

Attitude of Health Personnel↗
PubMed2001

Abdominal radiography after CT reveals urinary calculi: a method to predict usefulness of abdominal radiography on the basis of size and CT attenuation of calculi.

OBJECTIVE: The purpose of this study was to determine if the radiographic visibility of urinary tract calculi could be predicted on the basis of CT features. MATERIALS AND METHODS: The images of 26 patients whose urinary tract calculi were revealed on unenhanced helical CT and who also underwent digital abdominal radiography were retrospectively reviewed. CT features studied included size and CT attenuation of the calculi. These CT findings were correlated with the ability to detect the same calculi with radiography. RESULTS: Forty-nine urinary tract calculi were detected with unenhanced helical CT in 26 patients. Twenty-six (53%) calculi were visible on radiography. Most (79%) calculi larger than 5 mm were detectable with radiography (p < 0.01). One (8%) of 13 calculi with CT attenuation below 200 H was detectable on radiographs. Ninety-five percent (21/22) of calculi with CT attenuation exceeding 300 H were visible on radiographs (p < 0.0001). The one remaining calculus was obscured by overlying anatomy. CONCLUSION: Radiographic surveillance of urinary tract calculi detected with CT may not be useful if the calculi have a CT attenuation below 200 H. Most calculi larger than 5 mm and nearly all calculi with a CT attenuation exceeding 300 H can be seen on abdominal radiographs.

Adult↗
PubMed2001

Gastritis: classification, pathology, and radiology.

Gastritis has a broad pathologic spectrum and anatomic distribution, as well as an evolving etiology. The Sydney pathologic classification of gastritis, which appeared in 1990 and was revised in 1994, emphasized the importance of combining etiologic, topographic, and morphologic criteria for establishing clinically useful diagnoses. Using this revised Sydney pathologic classification as a guide, we report a simpler and more practical radiologic approach to gastritis. We emphasize those types of gastritis that may be detected on radiologic examination and illustrate typical findings.

Gastritis↗