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Biomedical subjects

C Chin

Publications and source records attributed to C Chin.

At least 19 recordsLinked to original sources
PubMed2002

Residential water supply as a likely cause of community-acquired Legionnaires' disease in an immunocompromised host.

A 69-year-old man with Sweet's syndrome and myelodysplastic syndrome presented with pneumonia and respiratory distress. He had been taking corticosteroids and methotrexate. The diagnosis of Legionnaires' disease was established by the isolation of Legionella pneumophila serogroup 6 from sputum and a fourfold seroconversion of Legionella antibodies to 1:512. Legionella pneumophila serogroup 6 was isolated from faucets in two homes owned by the patient. Strains of Legionella pneumophila serogroup 6 isolated from the patient's sputum and from one home were demonstrated to be genetically identical by pulsed-field gel electrophoresis but different from strains found in the other home and in a hospital outpatient clinic that he visited. This case illustrates an emerging public health issue concerning acquisition of community-acquired Legionnaires' disease from the homes of immunocompromised hosts. This is the first such case reported in Asia.

Aged↗
PubMed2001

Antibody to the nonstructural protein NS1 of Japanese encephalitis virus: potential application of mAb-based indirect ELISA to differentiate infection from vaccination.

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to detect and differentiate the antibody responses to Japanese encephalitis (JE) virus nonstructural protein NS1 between infected and vaccinated individuals. The results showed that all convalescent sera from JE patients contained NS1-specific IgG antibodies, while 65 and 40% of these sera showed detectable NS1-specific IgM and IgA antibodies, respectively. Specificity analysis showed that NS1-specific IgM and IgA antibodies from JE patients do not cross-react to dengue virus NS1 glycoprotein, while IgG antibodies from 10% of JE patients showed significant cross-reaction to dengue virus NS1 glycoprotein. To differentiate infection from vaccination, the immune sera from 24 children vaccinated with inactivated JE vaccine were analyzed. The data showed that none of these immune sera had detectable NS1-specific IgG antibodies. The results demonstrated the potential application of JE NS1-specific indirect ELISA to differentiate infection from vaccination.

Adult↗
PubMed2000

Erratum

Explore the source record for details and available documents.

Journal Article↗
PubMed2000

N-methyl-D-aspartate receptor subunit NR2B is widely expressed throughout the rat diencephalon: an immunohistochemical study.

Glutamate (Glu), a major excitatory neurotransmitter within the hypothalamus and thalamus, acts upon many receptors, including the N-methyl-D-aspartate (NMDA) subtype. Abundant evidence suggests that variations in the subunit composition of NMDA receptors (NMDA-Rs) contribute to differences in Glu's immediate electrophysiological effects as well as to the patterns of signal transduction cascades it triggers to mediate long-term changes in neuronal function. We have previously shown that hypothalamic NMDA-Rs containing the NR2B subunit may be involved in the control of eating as well as in the mediation of physiological responses to osmotic stimuli. To broaden our understanding of diencephalic NMDA-R participation in other functions, we localized the NR2B subunit in the diencephalon of the adult male rat using immunoperoxidase, immunogold, and immunofluorescence techniques and an affinity-purified polyclonal antibody specific for the NR2B subunit of the NMDA-R. In addition, we used a monoclonal NR2B antibody with immunoperoxidase detection to confirm the NR2B distribution seen with the polyclonal antibody. In the hypothalamus, the highest levels of NR2B immunoreactivity (-ir) were found in the magnocellular neurosecretory system, including the paraventricular and supraoptic nuclei. A new finding was that intense NR2B-ir was present within perivascular "accessory" magnocellular groups of this system, including the nucleus circularis, anterior fornical nucleus, and scattered clusters of lateral hypothalamic cells apposed to blood vessels. Robust NR2B-ir was also present within the arcuate nucleus, the median eminence, and the tuberal nucleus, and light immunostaining was found in all other hypothalamic nuclei examined. In the thalamus, the highest NR2B-ir was observed in the medial habenula and the anterodorsal, paraventricular, rhomboid, reticular, and dorsal lateral geniculate nuclei. As in the hypothalamus, all thalamic nuclei examined displayed at least light immunostaining for this subunit. Control sections, including those incubated with the polyclonal NR2B antibody preadsorbed with its fusion protein, were virtually devoid of immunostaining. This demonstration that the NR2B subunit of the NMDA-R is widely distributed in the diencephalon, implicates it in a wide variety of functions, and provides a useful anatomical framework for establishing a comprehensive map of Glu receptor populations within this major subdivision of the brain.

Animals↗
PubMed2000

Immunolabeling reveals cellular localization of the N-methyl-D-aspartate receptor subunit NR2B in neurosecretory cells but not astrocytes of the rat magnocellular nuclei.

Previous studies suggest that activation of N-methyl-D-aspartate (NMDA) receptors facilitates phasic firing and spike clustering displayed by magnocellular neuroendocrine cells (MNCs) of the supraoptic (SON) and paraventricular nucleus of the hypothalamus (PVN). Osmotic stimulation produces similar activity patterns which, in turn, can lead to enhanced release of vasopressin and oxytocin from MNCs. Our laboratory has shown that dehydration regulates the expression of the NMDA receptor subunits, NR1 and NR2B, in the SON and PVN, suggesting their involvement in osmoregulation. In the present study, we examined the cellular localization of NR2B, one of the glutamate-binding subunits of the NMDA receptor, with an NR2B-specific antibody. Using double-label immunohistochemistry and three different detection methods with metallic, peroxidase, and fluorescence markers, it was found that both vasopressin and oxytocin-producing MNC populations synthesize NR2B. The incidence of NR2B colocalization with vasopressin-neurophysin in the SON and lateral magnocellular PVN (PVL) was 0.95 and 0.91, respectively. For oxytocin-neurophysin, the corresponding values were 0.97 and 0.95, respectively. Furthermore, the extent of colocalization in MNCs of the SON, PVL, retrochiasmatic SON, and accessory neurosecretory nuclei was similar. Astrocytes associated with the SON, and identified with antibodies targeting glial fibrillary acidic protein (GFAP) or vimentin, were not colabeled with NR2B. Our results demonstrate that NR2B protein is expressed by almost all MNCs and that it is equally prevalent in vasopressinergic and oxytocinergic populations of various magnocellular neuroendocrine nuclei supporting a role of NMDA receptors in MNC-mediated neurosecretory processes. Although NR2B may form part of functional NMDA receptors on MNCs, it is probably not present on astrocytes associated with nearby MNCs.

Animals↗
PubMed2000

High resolution feshbach spectroscopy of cesium

We measure high-resolution Feshbach resonance spectra for ultracold cesium atoms colliding in different hyperfine and magnetic sublevels. More than 25 resonances are observed for magnetic fields up to 230 G and their positions are measured with an accuracy down to 0.03 G. From these spectra several ground-state molecular interaction parameters can be extracted with sufficient accuracy to permit for the first time an unambiguous and accurate determination of cesium's ultracold collision properties [P. J. Leo, C. J. Williams, and P. S. Julienne, following Letter, Phys. Rev. Lett. 85, 2721 (2000)].

Journal Article↗
PubMed2000

Testing reminder and motivational telephone calls to increase screening mammography: a randomized study.

BACKGROUND: Prospective randomized trials have demonstrated that motivational telephone calls increase adherence to screening mammography. To better understand the effects of motivational calls and to maximize adherence, we conducted a randomized trial among women aged 50-79 years. METHODS: We created a stratified random sample of 5062 women due for mammograms within the Group Health Cooperative of Puget Sound, including 4099 women with prior mammography and 963 without it. We recruited and surveyed 3743 (74%) of the women before mailing a recommendation. After 2 months, 1765 (47%) of the 3743 women had not scheduled a mammogram and were randomly assigned to one of three intervention groups: a reminder post-card group (n = 590), a reminder telephone call group (n = 585), and a motivational telephone call addressing barriers group (n = 590). The telephone callers could schedule mammography. We used Cox proportional hazards models to estimate the hazard ratio (HR) and 95% confidence interval (CI) for documented mammography use by 1 year. RESULTS: Women who received reminder calls were more likely to get mammograms (HR = 1.9; 95% CI = 1.6-2.4) than women who were mailed postcards. The motivational and reminder calls (average length, 8.5 and 3.1 minutes, respectively) had equivalent effects (HR = 0.97; 95% CI = 0.8-1.2). After we controlled for the intervention effect, women with prior mammography (n = 1277) were much more likely to get a mammogram (HR = 3.4; 95% CI = 2.7-4.3) than women without prior use (n = 488). Higher income, but not race or more education, was associated with higher adherence. CONCLUSIONS: Reminding women to schedule an appointment was as efficacious as addressing barriers. Simple intervention groups should be included as comparison groups in randomized trials so that we better understand more complex intervention effects.

Affect↗
PubMed2000

Beyond optical molasses: 3D raman sideband cooling of atomic cesium to high phase-space density

We demonstrate a simple, general purpose method to cool neutral atoms. A sample containing 3x10(8) cesium atoms prepared in a magneto-optical trap is cooled and simultaneously spin polarized in 10 ms at a density of 1.1x10(11) cm (-3) to a phase space density nlambda(3)(dB) = 1/500, which is almost 3 orders of magnitude higher than attainable in free space with optical molasses. The technique is based on 3D degenerate Raman sideband cooling in optical lattices and remains efficient even at densities where the mean lattice site occupation is close to unity.

Journal Article↗
PubMed2000

Hantavirus infection in Taiwan: the experience of a geographically unique area.

Hantaviruses are rodent-borne viruses, and they, mainly the Hantaan (HTN) serotype, are the causative agents of a group of febrile nephropathies known as "hemorrhagic fever with renal syndrome (HFRS). " Despite the fact that HFRS is frequently reported in China, with an annual incidence of 50,000-100,000 cases, one puzzling observation that no local case of HFRS has been confirmed in Taiwan has yet to be explained. We hypothesized that the hantavirus strain prevailing in Taiwan mainly belongs to the mild strain, the Seoul (SEO) strain, and the absence of severe disease was related to the absence of HTN. To test these hypotheses, this epidemiologic study was performed, including a seroprevalence survey and phylogenetic analysis on hantavirus isolated from the rodent population trapped in major seaports, rural, and mountainous areas of Taiwan. This study also included rodents and viruses from two isolated islands, Kinmen and Matzu, which are geographically adjacent to the east coast of mainland China. There were a total of 5,461 rodents of 16 species captured, and R. norvegicus was the most common species, with an antibody prevalence much higher in international seaports (20%) than in rural regions (approximately 5%) and intermediate in some domestic seaports. By reverse transcriptase polymerase chain reaction (RT-PCR), 33.9% of the seropositive R. norvegicus were found to have amplifiable hantavirus sequences in their lung tissues, and subsequent phylogenetic analyses indicated that almost all hantavirus in Taiwan was most closely related to the prototype SEO strain, and no HTN strain was recovered from any rodent species indigenous to Taiwan. The seroprevalence of SEO infection in R. norvegicus on Kinmen and Matzu was also different from that in southern provinces of China but closely resembled that in seaports in Taiwan, and the SEO identified was genetically linked to Taiwanese SEO strains. These results substantiate our hypotheses, and suggest that the epidemiology of hantavirus infection in Taiwan are different from that in China, where the HTN and SEO strains and HFRS concurrently prevail.

Animals↗
PubMed2000

Dengue NS1-specific antibody responses: isotype distribution and serotyping in patients with Dengue fever and Dengue hemorrhagic fever.

To understand the antibody responses to dengue (DEN) nonstructural 1 (NS1) glycoprotein and their roles in protective immunity or pathogenesis of dengue fever (DF) and dengue hemorrhagic fever (DHF), we have analyzed the NS1-speccific IgM, IgA and IgG antibodies from patients with DF and DHF. An isotype-specific, indirect enzyme-linked immunosorbent assay (ELISA) was established by coating a NS1-specific monoclonal antibody (MAb), D2/8-1, to capture soluble NS1 antigens secreted in the culture supernatants of Vero cells infected with DEN virus. We observed strong anti-NS1 antibody responses in all of the convalescent sera of patients with DF and DHF. Similar NS1-specific isotypic and serotypic antibody responses were found in the sera from DF and DHF patients. The results showed that all DEN infections induced significant NS1-specific IgG, whereas 75% and 60% of primary DF patients vs. 40% and 90% of secondary DF patients produced IgM and IgA antibodies, respectively. Specificity analysis showed that DEN NS1-specific IgG and IgA antibodies cross-react strongly to Japanese encephalitis (JE) virus NS1 glycoprotein, whereas DEN NS1-specific IgM antibodies do not cross-react to JE virus NS1 glycoprotein at all. The serotype specificity of NS1-specific IgM, IgA and IgG were found to be 80%, 67% and 75% for primary infections, and 50%, 22% and 30% for secondary infections in positive samples of DF patients. Similar pattern was found in DHF patients. The results showed that all of the DF and DHF patients produced significant NS1-specific antibodies. We did not observe direct correlation between the anti-NS1 antibody responses and DHF because sera from patients with DF and DHF showed similar anti-NS1 antibody responses.

Antibodies, Monoclonal↗
PubMed2000

Safety and utility of the routine surveillance biopsy in pediatric patients 2 years after heart transplantation.

OBJECTIVES: The standard for diagnosing allograft rejection after heart transplantation is the endomyocardial biopsy, but the value of routine surveillance biopsies after 2 years after transplant is controversial. The objective of this study was to determine the necessity and safety of surveillance biopsies and to correlate rejection with signs and symptoms beyond the second post-transplant anniversary in pediatric patients. STUDY DESIGN: We reviewed the results of 899 biopsies and coincident clinical histories in 56 pediatric patients, comprising 314 patient-years of follow-up. Patients were classified as having symptoms or not based on a blinded review of their clinical status and echocardiograms. Biopsies were classified as negative or positive with established criteria. RESULTS: After biopsies performed less than 2 years after transplant or as a follow-up for a positive biopsy were excluded, 481 biopsies were available for analysis, of which 20 (4%) were positive. Positive biopsies were found in 15 (3%) of 456 biopsies in patients without symptoms compared with 5 (20%) of 25 biopsies in patients with symptoms. Patients with symptoms were 6 times more likely to have a positive biopsy compared with patients without symptoms. Of the positive rejection episodes, 75% occurred in patients without symptoms. CONCLUSION: Although rejection is uncommon in pediatric patients greater than 2 years after transplant, episodes of treatable allograft rejection can occur in the absence of clinical signs and symptoms. This study emphasizes the safety of and the need to continue to perform routine surveillance biopsies in patients without symptoms, even after the second post-transplant year.

Biopsy↗
PubMed2000

Outcome while awaiting heart transplantation in children: a comparison of congenital heart disease and cardiomyopathy.

BACKGROUND: Outcomes for children who undergo heart transplantation differ for children with congenital heart disease as compared to those with structurally normal hearts. Similar data have not been reported for these groups of patients for the morbidity and mortality associated with waiting for a donor. We report these data. METHODS: A retrospective review was performed for all pediatric patients who were listed for heart transplantation at Stanford from 1977 to 1996, comparing mortality and major morbidity for patients with congenital heart disease and those with cardiomyopathy and structurally normal hearts. RESULTS: There were 96 patients who met study criteria, of whom 67 were successfully transplanted. The median waiting time was 23 days. Survival at 30 days was 93% and at 90 days was 81%, with no difference between groups. Major complications were identified in 38% of patients with structurally normal hearts, vs 9% of patients with congenital heart disease (p < 0.001). CONCLUSIONS: Overall mortality is similar for patients with congenital heart disease and those with structurally normal hearts while listed for heart transplantation, but patients with congenital heart disease have fewer episodes of major morbidity during this time.

Actuarial Analysis↗
PubMed2000

Lipoprotein abnormalities are highly prevalent in pediatric heart transplant recipients.

The role of hyperlipidemia in graft coronary artery disease (GCAD) is controversial although hyper-triglyceridemia is an independent risk factor. Recent studies show that 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) inhibitors decrease the incidence of GCAD in adults. The incidence of GCAD in pediatric patients is lower than in adults; it is not clear whether age-related differences in lipid metabolism account for some of this protection. This study was performed to: characterize the lipoprotein profile in children after heart transplantation; demonstrate that total cholesterol (TC) is a poor marker for underlying lipoprotein abnormalities; and to compare lipid abnormalities in patients who had been converted from cyclosporin A (CsA) to tacrolimus. Seventy-one determinations of fasting lipoprotein profiles were performed in a cohort of 28 children. Each child had at least two determinations on separate occasions. TC, low-density lipoprotein (LDL), and serum triglyceride (TG) levels were categorized as abnormal if greater than the 75th percentile for age and gender. A high-density lipoprotein (HDL) level less than the 25th percentile was considered abnormal. Immunosuppression included CsA or tacrolimus, azathioprine, and prednisone. We found that 90% of the patients studied had abnormalities of either TG or HDL. In contrast, LDL tended to be normal when adjusted for age and gender. TC was a poor indicator of any underlying abnormality in TG, LDL, or HDL. In patients converted to tacrolimus, no significant differences were found in the levels of TG, LDL or HDL compared with each patient's respective values while receiving CsA. Hence, lipoprotein abnormalities among pediatric heart transplant recipients are highly prevalent. TC is a poor screening tool in the evaluation for lipid abnormalities. Lipoprotein profiles remain statistically unchanged after conversion from CsA to tacrolimus.

Adolescent↗
PubMed2000

A comparison of microbiologic flora of the sinuses and airway among cystic fibrosis patients with maxillary antrostomies.

The placement of maxillary antrostomies among cystic fibrosis (CF) patients has been used as a treatment to allow localized antibiotic lavage of infected sinus passages. This procedure is increasingly recommended by lung transplantation centers as a prerequisite prior to accepting a CF patient as a candidate for transplantation. Our study attempts to define the degree of identity between sinus, endotracheal and sputum cultures from 35 patients. The samples (n = 137) were collected within two weeks of each other. An analysis of the microbiologic type, strain, and antibiotic resistance patterns was undertaken. Randomization analysis was performed and a p-value of < 0.05 was considered significant. The results indicated a high degree of correlation between sinus-sputum pairs (n = 55) and endotracheal samples (p < 0.008). This study provides evidence that there is a potential for cross-infection between sinus passages and the lower airway. The localized irrigation of CF sinus cavities post-transplantation may be warranted in an attempt to reduce bacterial counts and potential direct infection of the allograft. However, it is unlikely that this will eliminate this risk because bacterial colonization continues and the CF trachea is another source of infection.

Adolescent↗
PubMed2000

Women recovering from first-time myocardial infarction (MI): a feminist qualitative study.

Although myocardial infarction (MI) is a leading cause of death and disablement for women internationally, little is known about women's recovery. This paper describes an exploratory descriptive study that was informed by feminist principles, and which aimed to explore the recovery experiences of a group of women survivors of first-time MI in the initial period following discharge from hospital. A total of 10 female survivors were interviewed using an open-ended semi-structured interview schedule administered at 7, 14 and 21 days post-hospital discharge. Findings revealed that recovery was experienced as a complex process, initially characterized by fear and uncertainty. Over the duration of the study these feelings were replaced with a more positive outlook, a return of energy, and a sense of confidence in the future. Participants identified an unmet need for reliable information which persisted over the duration of the study. The findings of this study have implications for nursing practice and research. Chief among these is the issue of effective provision of information to women following an acute MI. The importance of providing relevant information to be understood and retained by people experiencing crisis cannot be overstated. Equally important are the provision of opportunities for patients to have regular contact with health professionals to question and seek clarifying information. These findings should now be tested on larger populations.

Adaptation, Psychological↗
PubMed2000

Comparison of exogenous surfactant and positive end-expiratory pressure therapies in a model of human breast milk-induced acute lung injury in rabbits.

To evaluate surfactant and positive end-expiratory pressure (PEEP) as potential therapies for the acute lung injury after tracheal instillation of 0.8 ml kg-1 human breast milk (HBM) acidified to pH 1.8, adult white rabbits were anaesthetized, tracheostomized, ventilated and randomized to (six rabbits per treatment): (i) no treatment after HBM (control); (ii) exogenous Bovine surfactant (100 mg kg-1) 1 h after HBM; (iii) PEEP-pre (0.5 kPa PEEP) before and after HBM; or (iv) PEEP-post (0.5 kPa PEEP) after HBM. A fifth group of six rabbits received no tracheal instillate (no aspirate). The alveolar to arterial oxygen tension gradient (A-aDO2) and dynamic compliance were measured pre-injury and hourly for 4 h. At post-mortem, the lungs were examined histologically. A-aDO2 in all four HBM-injured groups increased to a maximum at 1 h post-injury; A-aDO2 then returned towards the baseline in the surfactant and PEEP-post groups, but remained increased in the PEEP-pre and control groups. Dynamic compliance decreased in all four HBM-injured groups. A-aDO2 and compliance were unchanged in the no aspirate group. Bronchoalveolar architecture after surfactant therapy was normal. We conclude that surfactant is a more effective therapy for HBM-induced lung injury than either 0.5 kPa PEEP-post or PEEP-pre injury.

Administration, Inhalation↗
PubMed2000

A preliminary study of the prognostic value of proton magnetic resonance spectroscopic imaging in gamma knife radiosurgery of recurrent malignant gliomas.

OBJECTIVE: The goal of this study was to investigate the use of proton magnetic resonance spectroscopic imaging as a prognostic indicator in gamma knife radiosurgery of recurrent gliomas. METHODS: Thirty-six patients with recurrent gliomas were studied with proton magnetic resonance spectroscopic imaging at the time of radiosurgery, and with conventional magnetic resonance imaging examinations at regular time intervals until the initiation of a new treatment strategy. Patients were categorized on the basis of their initial spectroscopic results, and their performance was assessed in terms of change in contrast-enhancing volume, time to further treatment, and survival. RESULTS: The trends in the overall population were toward more extensive increase in the percent contrast-enhancing volume, a decreased time to further treatment, and a reduced survival time for patients with more extensive initial metabolic abnormalities. Statistical analysis of the subpopulation of patients with glioblastoma multiforme found a significant increase in relative contrast-enhancing volume (P < 0.01, Wilcoxon signed-rank test), a decrease in time to further treatment (P < 0.01, log-rank test), and a reduction in survival time (P < 0.01, log-rank test) for patients with regions containing tumor-suggestive spectra outside the gamma knife target, compared with patients exhibiting spectral abnormalities restricted to the gamma knife target. Further studies are needed to establish statistical significance for patients with lower-grade lesions and to confirm the results observed in this study. CONCLUSION: The pretreatment spectroscopic results provided information that was predictive of outcome for this patient pool, both in local control (change in contrast-enhancing volume) and global outcome (time to further treatment and survival). This modality may have an important role in improving the selection, planning, and treatment process for glioma patients.

Adult↗