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Biomedical subjects

William Wong

Publications and source records attributed to William Wong.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiologic study and containment of a nosocomial outbreak of severe acute respiratory syndrome in a medical center in Kaohsiung, Taiwan.

OBJECTIVE: We conducted an epidemiologic investigation at the beginning of a nosocomial outbreak of severe acute respiratory syndrome (SARS) to clarify the dynamics of SARS transmission, the magnitude of the SARS outbreak, and the impact of the outbreak on the community. METHODS: We identified all potential cases of nosocomially acquired SARS, linked them to the most likely infection source, and described the hospital containment measures. SETTING: A 2,300-bed medical center in Kaohsiung, Taiwan. RESULTS: A total of 55 cases of SARS were identified, and 227 hospital workers were quarantined. The index patient and neighboring patients were isolated. A chest physician team reviewed medical charts and chest radiographs and monitored the development of SARS in patients staying in the ward. The presence of underlying lung disease and immunocompromise in some patients made the diagnosis of SARS difficult. Some cases of SARS were diagnosed after the patients had died. Medical personnel were infected only if they cared for patients with unrecognized SARS, and caretakers played important roles in transmission of SARS to family members. As the number of cases of nosocomial SARS increased, the hospital closed the affected ward and expedited construction of negative-pressure rooms on other vacated floors for patient cohorting, and the last case in the hospital was identified 1 week later. CONCLUSIONS: Timely recognition of SARS is extremely important. However, given the limitations of SARS testing, possible loss of epidemic links, and the nonspecific clinical presentations in hospitalized patients, it is very important to establish cohorts of persons with low, medium, and high likelihoods of SARS acquisition. Rapid closure of affected wards may minimize the impact on hospital operations. Establishment of hospitals dedicated to appropriate treatment of patients with SARS might minimize the impact of the disease in future epidemics.

Aged↗
PubMed2006

Detection of acute HIV infections in high-risk patients in California.

BACKGROUND: Given the strong relation between sexually transmitted diseases (STDs) and the spread of HIV infection, recent outbreaks of syphilis in the United States could lead to increased rates of new HIV infection. STD clinics serving persons at risk for syphilis would be logical sites to monitor rates of acute HIV infection. The detection of acute HIV infection, however, is not routine and requires the use of HIV RNA testing in combination with HIV antibody testing. METHODS: To determine the rate of acute HIV infection, we performed HIV RNA testing on pooled HIV antibody-negative specimens from persons seeking care at San Francisco City Clinic (SFCC) and from men seeking care at 3 STD clinics in Los Angeles. We compared prevalence of acute HIV infection among those groups. RESULTS: From October 2003 to July 2004, we tested 3075 specimens from persons at the SFCC, of which 105 (3%) were HIV antibody-positive and 11 were HIV RNA-positive/HIV antibody-negative, resulting in a prevalence of acute HIV infection of 36 per 10,000 (95% confidence interval [CI]: 26 to 50 per 10,000) and increasing by 10.5% the diagnostic yield of HIV RNA testing compared with standard testing. From February 2004 to April 2004, 1712 specimens were tested from men at 3 Los Angeles STD clinics, of which 14 (0.82%) were HIV-positive by enzyme immunoassay testing and 1 was HIV RNA-positive/HIV antibody-negative, resulting in a prevalence of 6 per 10,000 (95% CI: 3 to 13 per 10,000) and increasing the diagnostic yield for HIV infection by 7.1%. CONCLUSIONS: In our study, the addition of HIV RNA screening to routine HIV antibody testing in STD clinics identified a substantial increased proportion of HIV-infected persons at high risk for further HIV transmission, who would have been missed by routine HIV counseling and testing protocols. Further evaluation of the addition of HIV RNA screening to routine HIV antibody testing is warranted.

Adult↗
PubMed2006

The skin and the mind.

BACKGROUND: The intimate relationship of the skin and the mind illustrates the importance of a holistic approach in caring for patients with skin problems. Habits related to psychological problems may lead to skin problems such as lichen simplex chronicus and acne excoriée. Emotional stress may affect skin diseases such as atopic dermatitis, perioral dermatitis, pompholyx, and plaque psoriasis. OBJECTIVE: This article describes the relationship between the mind and skin disease. DISCUSSION: Skin disease can exert a profound effect on the psychosocial dimension of a patient's life. Its effect on quality of life can be objectively assessed and documented by validated tools specific for the skin. Patient rated measures should be taken into account when evaluating the efficacy and adverse effects of treatments for skin disease.

Acne Vulgaris↗
PubMed2005

Prevalence of rectal, urethral, and pharyngeal chlamydia and gonorrhea detected in 2 clinical settings among men who have sex with men: San Francisco, California, 2003.

BACKGROUND: The Centers for Disease Control and Prevention developed screening and diagnostic testing guidelines for chlamydia and gonorrhea at urethral, rectal, and pharyngeal sites for men who have sex with men (MSM). However, in most clinical settings, rectal chlamydial testing is not performed for MSM, and primarily sexually transmitted disease (STD) clinics alone perform routine rectal and pharyngeal gonorrhea screening for asymptomatic men. METHODS: We evaluated the prevalence of rectal, urethral, and pharyngeal chlamydial and gonococcal infections among MSM seen at the municipal STD clinic and the gay men's community health center. We also determined the proportion of asymptomatic rectal infections, described the patterns of single and multiple anatomic sites of infection, and evaluated the proportion of chlamydial infections that would be missed and not treated if MSM were not routinely tested for chlamydia. We tested specimens using previously validated nucleic acid amplification tests (NAATs). RESULTS: The prevalence of infection varied by anatomic site (chlamydia: rectal, 7.9%; urethral, 5.2%; and pharyngeal, 1.4%; for gonorrhea, rectal, 6.9%; urethral, 6.0%; and pharyngeal, 9.2%). Approximately 85% of rectal infections were asymptomatic supporting the need for routine screening. Because 53% of chlamydial infections and 64% of gonococcal infections were at nonurethral sites, these infections would be missed and not treated if only urethral screening was performed. In addition, >70% of chlamydial infections would be missed and not treated if MSM were tested only for gonorrhea. CONCLUSIONS: Because these infections enhance both HIV transmission and susceptibility, clinical settings serving MSM should evaluate the prevalence of chlamydial and gonococcal infections by anatomic site using validated NAATs.

Adult↗
PubMed2005

Primary care physicians in Hong Kong and Canada--how did their practices differ during the SARS epidemic?

BACKGROUND: Hong Kong and Canada have very different primary health care systems. We thus hypothesized family physicians between the two places would be different in how they protected themselves, their staff and families during the epidemic. OBJECTIVE: The purpose of this study was to explore and contrast the impact of SARS on family physicians in Hong Kong and Toronto. METHODS: A postal questionnaire was designed and sent to 183 tutors affiliated with the Chinese University of Hong Kong with 137 replies (74.8%). In Toronto, 150 questionnaires were sent to academic family physicians affiliated with the University of Toronto with 51 replies (34%). RESULTS: All agreed SARS had changed their clinical behaviour. For public health measures in the control of SARS, Hong Kong physicians were less likely to quarantined themselves (77.1% versus 19.4%, P < 0.01) or gave quarantine leave to staff (95% versus 59.7%, P < 0.01) after exposure to probable or suspected SARS. However, they were more likely to wear a mask (52.7% versus 97.7%, P = 0) during consultation, having support staff to wear masks (68.6% versus 97.8%, P = 0) and test patient's temperature (47.1% versus 68.1%, P < 0.01). CONCLUSION: There were noticeable differences in how family physicians deal with SARS between the two cities. As SARS emerged as a global disease, better understanding of practice differences among physicians from different countries would facilitate globalization of public health.

Canada↗
PubMed2005

Are your hands clean enough for point-of-care electrolyte analysis?

AIM: To investigate clinically significant analytical interference in point-of-care electrolyte analysis caused by contamination of blood specimens with hand disinfectant. METHODS: Six different hand hygiene products were added separately to heparinised blood samples in varying amounts as contaminant. The contaminated samples were analysed by three different blood gas and electrolyte analysers for assessing interference on measured whole blood sodium and potassium concentrations. RESULTS: There were significant analytical interferences caused by hand hygiene product contamination that varied depending on the combination of disinfectant and analyser. Small amounts of Microshield Antibacterial Hand Gel contamination caused large increases in measured sodium concentration. Such effect was much greater compared with the other five products tested, and started to occur at much lower levels of contamination. There was a trend towards lower sodium results in blood samples contaminated with Hexol Antiseptic Lotion (Hexol), the hand hygiene product that we used initially. Apart from AiE Hand Sanitizer, all the other hand disinfectants, especially Hexol, significantly elevated the measured potassium concentration, particularly when a direct ion-selective electrode method was used for measurement. CONCLUSIONS: Hand disinfectant products can significantly interfere with blood electrolyte analysis. Proper precautions must be taken against contamination since the resultant errors can adversely affect the clinical management of patients.

Anti-Bacterial Agents↗
PubMed2005

Risk factors for early syphilis among gay and bisexual men seen in an STD clinic: San Francisco, 2002-2003.

BACKGROUND: Substantial increases in syphilis among gay and bisexual men have been reported in San Francisco. GOAL: To identify risk factors for early syphilis infection among gay and bisexual men attending the San Francisco municipal STD clinic (City Clinic). STUDY: Cross-sectional, self-administered, behavioral survey of gay and bisexual men attending City Clinic between November 2002 and March 2003 linked with electronic medical record data. RESULTS: Among 1318 gay and bisexual men surveyed, 53 (4.0%) were diagnosed with early syphilis. The final multivariate model included nonwhite race (OR = 2.1 [1.1-4.4]), HIV-infection (OR = 3.9 [2.0-7.7]), using both methamphetamine and sildenafil (Viagra(R)) (OR = 6.2 [2.6-14.9]), using methamphetamine without sildenafil (OR = 3.2 [1.3-7.6]), using sildenafil without methamphetamines (OR = 0.9 [0.3-2.9]), stronger gay community affiliation (OR = 2.3 [1.2-4.6]), and having recent Internet partners (OR = 2.1 [1.0-4.3]). CONCLUSIONS: Syphilis prevention efforts should address methamphetamine and sildenafil use among gay and bisexual men and require strong and substantive involvement with the gay community to address syphilis in San Francisco.

Adult↗
PubMed2005

The public health response to epidemic syphilis, San Francisco, 1999-2004.

In 1999, the Centers for Disease Control and Prevention launched the National Plan to Eliminate Syphilis. From 1999 to 2003 in San Francisco, early syphilis was epidemic, increasing from 44 cases to 522 cases a year. Syphilis cases were more likely to be in gay or bisexual men, those with human immunodeficiency virus (HIV) infection, those who had anonymous partners, and those who met sex partners on the Internet. Increases in sexual activity and sexual risk behavior in men who have sex with men during this period have been attributed to the improved physical health of HIV-infected men on highly active antiretroviral therapy, HIV treatment optimism, increases in methamphetamine use, and the use of Viagra. The San Francisco Department of Public Health's response to the epidemic included enhanced surveillance, expanded clinical and testing services, provider and community mobilization and sexual health education, and risk factor identification and abatement through investigations, public health advocacy, and treatment. Collaborations with community-based organizations and local businesses were key to the successful implementation of disease-control efforts. A multitude of converging risk factors and new environments contributed to the syphilis epidemic, requiring a comprehensive, innovative, and flexible disease-control strategy.

Contact Tracing↗
PubMed2005

Activities to increase provider awareness of early syphilis in men who have sex with men in 8 cities, 2000-2004.

OBJECTIVE: Describe provider awareness campaigns undertaken in response to syphilis epidemics among men who have sex with men (MSM). METHODS: Descriptive data from 8 cities facing MSM syphilis epidemics was compiled. RESULTS: Provider awareness efforts included medical alerts, provider visits, lectures to providers on symptom recognition and treatment, and ongoing provision of syphilis and other sexually transmitted diseases (STD) morbidity information through mailings, visits, and e-mail communications. Increases in private provider reporting of syphilis cases followed provider visits in Atlanta and overall provider education efforts in New York City. Decreases in reporting delays and increases in physician calls to the STD program were reported in San Francisco following provider syphilis lectures. Increases in provider participation in community action meetings followed provider awareness efforts in Houston, Chicago, and Miami. CONCLUSIONS: Various methods were used to increase provider awareness of syphilis in these 8 cities. The cost and impact of these activities merits more formal evaluation to determine their contribution to syphilis control in MSM.

Disease Outbreaks↗
PubMed2005

Cerebral thrombosis in childhood nephrosis.

Sinovenous thrombosis is an uncommon but serious complication associated with nephrotic syndrome in children. We describe a 9-year-old Caucasian boy who presented with dehydration, vague neurological symptoms and seizures. A diagnosis of nephrotic syndrome was made during the course of hospitalization. The serum antithrombin III level was decreased and brain imaging showed cerebral sinovenous thrombosis. Anticoagulant therapy with heparin was commenced and the patient made a slow but gradual clinical, as well as radiological recovery. We describe this case and review available literature to highlight the importance of suspecting and recognizing this potentially life threatening complication and initiating early treatment.

Child↗
PubMed2004

Treatment of Wilms tumor-related hypertension with losartan and captopril.

Hypertension is commonly associated with Wilms tumor, but hypertension secondary to renin-secreting Wilms tumor is uncommon. We present an infant with severe hypertension and renin hypersecretion, which was resistant to multiple antihypertensive agents. Blood pressure was eventually controlled with a combination of captopril and losartan.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2004

The N- and C-terminal peptides of hIL8/CXCL8 are ligands for hCXCR1 and hCXCR2.

Chemokines are small cytokines that function in immune responses, wound healing, and pathological conditions such as chronic inflammation and tumorigenesis. This multifunctionality has been attributed primarily to ligand interaction with multiple or dimerized receptors. However, multifunctionality could also result from interactions of the receptors with small peptides produced by processing of the chemokines. Chemokine peptides are functional in vivo, but it is not yet known whether they can interact with and activate their receptors. The work presented here examines the interactions between the two forms of human interleukin 8 (hIL-8), and its N- and C-peptides, with the chemokine receptors hCXCR1 and hCXCR2. We used a Tet-on retroviral system to introduce CXCR1 into mouse NIH 3T3 cells (that lack endogenous CXCR1) and monitored activation of this receptor by the ligands by using quantitative Ca2+ imaging and mitogen-activated protein kinase (MAPK) activation. We found that the N and C termini of the chemokine can stimulate the respective CXCR1 to induce intracellular Ca2+ release and MAPK activation independent of the other regions of the molecules. Furthermore, we showed that these peptides can also stimulate chemotaxis of several cell types, including primary human microvascular endothelial cells, and that this function is specific and mediated by hCXCR1 and/or hCXCR2. These findings advance understanding of the multifunctionality exhibited by chemokines, reveal a new mode of functional regulation, and may serve as the basis for therapeutic targeting.

Animals↗
PubMed2004

Vaccination of chickens against H5N1 avian influenza in the face of an outbreak interrupts virus transmission.

Vaccination of chickens with a commercially available killed H5N2 vaccine was being evaluated as an additional tool to enhanced biosecurity measures and intensive surveillance for control of highly pathogenic avian influenza subtype H5N1 disease in Hong Kong in 2002. In December 2002 to January 2003, there were outbreaks of H5N1 disease in waterfowl in two recreational parks, wild water birds, several poultry markets and five chicken farms. In addition to quarantine, depopulation of the affected sheds and increased biosecurity, vaccination of the unaffected sheds and surrounding unvaccinated farms was undertaken on three farms. In at least two farms, infection spread to the recently vaccinated sheds with low rates of H5N1 mortality in sheds when the chickens were between 9 and 18 days post-vaccination. However, after 18 days post-vaccination no more deaths from H5N1 avian influenza occurred and intensive monitoring by virus culture on these farms showed no evidence of asymptomatic shedding of the virus. This provides evidence that H5 vaccine can interrupt virus transmission in a field setting.

Agriculture↗
PubMed2004

By-person factor analysis in clinical ethical decision making: Q methodology in end-of-life care decisions.

OBJECTIVE: To determine the usefulness of Q methodology to locate and describe shared subjective influences on clinical decision making among participant physicians using hypothetical cases containing common ethical issues. DESIGN: Qualitative study using by-person factor analysis of subjective Q sort data matrix. SETTING: University medical center. PARTICIPANTS: Convenience sample of internal medicine attending physicians and house staff (n = 35) at one midwestern academic health sciences center. INTERVENTIONS: Presented with four hypothetical cases involving urgent decision making near the end of life, participants selected one of three specific clinical actions offered for each case. Immediately afterward and while considering their decision, each respondent sorted twenty-five subjective self-referent items in terms of the influence of each statement on their decision-making process. By-person factor analysis, where participants are defined as variates, yielded information about the attitudinal background the physicians brought to their consideration of each hypothetical case. We performed a second-order factor analysis on all of the subjective viewpoints to determine if a smaller core of shared attitudes existed across some or all of the four case vignettes. Factor scores for each item and post-sort comments from interviews conducted individually with each respondent guided the interpretation of ethical perspective used by these respondents in making clinical decisions about the cases. MEASUREMENTS AND MAIN RESULTS: Second-order factor analysis on seventeen viewpoints used by physicians in the four hypothetical urgent decision cases revealed three moderately correlated (r2 < 40%) subjective core attitudinal guides used broadly among all the cases and among sixteen of the seventeen original factors. Across all the cases, our participants were guided in general by: (1) patient-focused beneficence, (2) a patient- and surrogate-focused perspective that includes risk avoidance, and (3) best interest of the patient guided by ethical values. Economic impact on the physician, expediency in resolution of the situation, and the expense of medical treatment were not found to be influential determinants in this study. CONCLUSIONS: Q sorting and by-person factor analysis are useful qualitative methodological tools to study the complex structure of subjective attitudes that influence physicians in making medical decisions. This study revealed the subjective viewpoints used by our physician participants as they made ethically challenging treatment decisions. The three second-order factors identified here are grounded in current bioethical values as well as the personal traits of physicians. The participants' decision methods appear to resemble casuistry more than principle-based decision making. Generalizability of results will require further studies.

Adult↗
PubMed2003

Renal length and inulin clearance in the radiologically normal single kidney.

Compensatory hypertrophy of a single functioning kidney is well described and has been shown to occur in utero. The long-term effects of hypertrophy and hyperfiltration in this situation are unknown. This study defined the growth parameters for single kidneys during childhood and correlated them with inulin clearance. Patients were those who had a radiologically "normal" single kidney, where the contralateral kidney was known to be non-functioning from infancy. Data were obtained from 74 children (40 boys and 34 girls) drawn from a registry of cases with a single kidney, and in whom simultaneous measurements of inulin clearance and renal length had been made at around 5, 10, and 16 years of age. Renal length was taken as the maximal bipolar measurement using real-time ultrasound scan. Inulin clearance was by continuous infusion technique. Nomograms for single kidney growth were determined against age, height, weight, and body surface area. Renal growth was correlated with inulin clearance. Renal length was found to correlate best with body surface area ( r=0.85, P<0.001), but this was not significantly superior to correlations with age, height, or weight separately. Inulin clearance per body surface area correlated positively with standardized renal length, i.e., Z score for renal length normalized for body surface area ( r=0.53, P<0.001). The larger kidneys have a higher glomerular filtration rate. Provided that the nephron number in the single kidney is similar to that in a paired kidney, single kidneys are hypertrophied and the single nephron glomerular filtration rate is likely to be abnormally high in these children.

Adolescent↗
PubMed2003

Expression patterns of vascular endothelial growth factor in human cardiac allografts: association with rejection.

BACKGROUND: Vascular endothelial growth factor (VEGF), a major angiogenesis factor, has been found to have proinflammatory properties in vivo in several chronic inflammatory diseases. However, little is known of the expression or function of VEGF in acute and chronic allograft rejection. METHODS: In a cross-sectional analysis, we evaluated the expression of VEGF by immunohistochemistry in human endomyocardial biopsies (n=101) from 10 cardiac transplant patients. We correlated expression (scores from 0-4) with CD3+ T cell, CD68+ monocyte and macrophage infiltrates, or rejection (International Society of Heart and Lung Transplantation grades 0-4). In addition, we evaluated the temporal patterns of VEGF expression in consecutive biopsies from seven patients (total of 74 biopsies) who were assessed for the development of graft vascular disease (GVD) by intravascular ultrasonography at 1 year posttransplantation. RESULTS: VEGF is expressed in normal human endomyocardial biopsies at low levels and is induced (scores >1) in association with CD3+ T cells (odds ratio [OR], 19.90; P<0.001), CD68+ monocyte and macrophage infiltrates (OR, 8.49; P<0.001), and all grades of acute rejection (OR, 5.4; P<0.001). Increases in VEGF expression were persistent during the first posttransplant year in biopsies from four patients who demonstrated evidence of GVD (mean annual score of 2.3). In contrast, limited expression of VEGF was found in three patients without GVD (mean annual score 1.2). CONCLUSIONS: These findings define VEGF as an important proinflammatory cytokine after transplantation and indicate that its expression pattern might identify patients at risk for the development of GVD.

Adult↗