Kenneth W Tsang

The University of Hong Kong, Hong Kong, Hong Kong

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Publications (70)414.54 Total impact

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    P L Ho · W C Yam · K W T Tsang · W M Lai
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    ABSTRACT: 1. Extended-spectrum beta-lactamase(ESBL) resistance in Enterobacter spp may be under-recognised. 2. Detection methods for ESBL resistance in Enterobacter spp may need to be modified.
    Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine 12/2009; 15 Suppl 9:4-5.
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    Kenneth W Tsang · Diana Bilton
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    ABSTRACT: Bronchiectasis is a common disease in the Asia-Pacific and affected patients suffer from chronic sputum production and recurrent exacerbations. Bronchiectasis is largely idiopathic although there is diverse aetiology. The pathogenesis of bronchiectasis comprises infective, inflammatory and emzymetic elements. These interact to perpetuate continued airway damage in bronchiectasis leading to progressive airway and lung damages. Treatment of bronchiectasis is unsatisfactory and there are only very few trials. Existing data suggest some efficacy of inhaled corticosteroid therapy, which has been shown recently to clinical and anti-inflammatory properties in bronchiectasis. Immunomodulating agent such as low-dose macrolides have also been shown to have some efficacy although more data are needed to advocate their long-term usage. Antibiotic therapy is complex in bronchiectasis and includes short-term empirical treatment for acute exacerbation, and consideration of long-term maintenance of oral, nebulized and i.v. therapy. This long-neglected illness should receive more research attention in order that we can have better understanding of its aetiology, pathogenesis and treatment.
    Respirology 08/2009; 14(5):637-50. DOI:10.1111/j.1440-1843.2009.01569.x · 3.50 Impact Factor
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    Kenneth W Tsang · Thomas M File
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    ABSTRACT: Asia is a highly heterogeneous region with vastly different cultures, social constitutions and populations affected by a wide spectrum of respiratory diseases caused by tropical pathogens. Asian patients with community-acquired pneumonia differ from their Western counterparts in microbiological aetiology, in particular the prominence of Gram-negative organisms, Mycobacterium tuberculosis, Burkholderia pseudomallei and Staphylococcus aureus. In addition, the differences in socioeconomic and health-care infrastructures limit the usefulness of Western management guidelines for pneumonia in Asia. The importance of emerging infectious diseases such as severe acute respiratory syndrome and avian influenza infection remain as close concerns for practising respirologists in Asia. Specific infections such as melioidosis, dengue haemorrhagic fever, scrub typhus, leptospirosis, salmonellosis, penicilliosis marneffei, malaria, amoebiasis, paragonimiasis, strongyloidiasis, gnathostomiasis, trinchinellosis, schistosomiasis and echinococcosis occur commonly in Asia and manifest with a prominent respiratory component. Pulmonary eosinophilia, endemic in parts of Asia, could occur with a wide range of tropical infections. Tropical eosinophilia is believed to be a hyper-sensitivity reaction to degenerating microfilariae trapped in the lungs. This article attempts to address the key respiratory issues in these respiratory infections unique to Asia and highlight the important diagnostic and management issues faced by practising respirologists.
    Respirology 12/2008; 13(7):937-49. DOI:10.1111/j.1440-1843.2008.01409.x · 3.50 Impact Factor
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    ABSTRACT: The burden of lung disease in Hong Kong is not known. This study determined the mortality and hospitalization rates of respiratory diseases in Hong Kong in 2005, their trend in the past decade and their incidence/prevalence. Mortality data were obtained from the Department of Health and hospitalization data from the Hospital Authority, Hong Kong. Incidence/prevalence data were obtained from local registries or local studies. Trends of mortality and hospitalization rates of various respiratory diseases from 1997 and 2005 were calculated after age standardization and were tested for significance using negative binomial regression analysis. Age standardized mortality rates in Hong Kong were compared with those of the UK and globally. Respiratory disease was the most common cause of mortality and hospitalization in Hong Kong in 2005. Globally and in the UK, cardiovascular disease ranked first in mortality. Respiratory infections ranked first in respiratory mortality, followed by respiratory tract cancer and chronic obstructive lung disease. Respiratory infections also ranked first followed by chronic obstructive lung disease in the utilization of respiratory inpatient bed-days. While mortality rates from all respiratory diseases decreased in the past decade, hospitalization rates remained unchanged. Unlike other respiratory diseases, mortality from respiratory infections have increased since 2001. Smoking is the most important risk factor in non-communicable respiratory diseases. Respiratory disease is responsible for the highest health-care burden locally. Increased efforts in improving management and prevention of these diseases, including tobacco control, improving air quality and vaccination against influenza and pneumococci, are necessary.
    Respirology 11/2008; 13 Suppl 4:S133-65. DOI:10.1111/j.1440-1843.2008.01394.x · 3.50 Impact Factor
  • David S Hui · Kenneth W Tsang
    Severe Acute Respiratory Syndrome, 01/2008: pages 36 - 41; , ISBN: 9780470755952
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    Cecilia Cheng · Wai-man Wong · Kenneth W Tsang
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    ABSTRACT: In this study, the authors examined perceived benefits and costs of the outbreak of severe acute respiratory syndrome (SARS). Mixed accounts of benefits and costs, rather than exclusive accounts of only benefits or costs, were proposed to be characterized by nondefensiveness and enduring changes in psychosocial resources. Participants were 70 SARS recoverers, 59 family members of SARS recoverers, and 172 healthy adults residing in Hong Kong--a SARS-affected region. Results show that participants giving an exclusive account of benefits had higher levels of defensiveness than those giving a mixed account and those giving an exclusive account of costs. Only the perceived impact of benefits given in mixed accounts were related to future accruements in personal and social resources over an 18-month period.
    Journal of Consulting and Clinical Psychology 11/2006; 74(5):870-9. DOI:10.1037/0022-006X.74.5.870 · 4.85 Impact Factor
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    Respirology 10/2006; 11(5):520-2. DOI:10.1111/j.1440-1843.2006.00885.x · 3.50 Impact Factor
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    ABSTRACT: Antioxidants play an important role in counteracting the effects of potential carcinogens. We investigated the risk of lung cancer development with respect to manganese superoxide dismutase (MnSOD) and catalase genetic polymorphisms and their association with erythrocyte antioxidant activities. This was a case-control study involving patients with confirmed lung cancer and age-matched healthy controls. Genotyping of MnSOD and catalase in DNA extracted from peripheral white cells was performed by polymerase chain reaction-based restriction fragment length polymorphism. Erythrocyte superoxide dismutase and catalase activities were measured spectrophotometrically using chemical kinetic reactions. We recruited 240 patients with lung cancer (63% male, aged 55.6 +/- 11.9 years, 58% adenocarcinoma, 85% clinical stage III or IV) and 240 age-matched healthy controls. The frequencies of the Val allele of MnSOD gene and the C allele of catalase gene were common (>86% and 90%, respectively), with similar distribution, in both patients with lung cancer and controls. The homozygous variant genotypes of MnSOD and catalase were not associated with increased lung cancer risk. The erythrocyte SOD and catalase activity was significantly lower among all patients with lung cancer as a whole compared with controls, irrespective of genotypes. However, patients with adenocarcinoma and non-adenocarcinoma showed differences in SOD and catalase activity among different genotypes in comparison with controls. The common Val16Ala MnSOD polymorphism and C-T substitution in the promoter region of the catalase gene do not confer increased or reduced risk of lung cancer in Chinese in Hong Kong.
    Journal of thoracic oncology: official publication of the International Association for the Study of Lung Cancer 09/2006; 1(7):648-53. DOI:10.1097/01243894-200609000-00008 · 5.80 Impact Factor
  • P L Ho · T L Que · T K Ng · S S Chiu · R W H Yung · K W T Tsang
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    ABSTRACT: In a retrospective study designed to gather information in a region with high antimicrobial resistance, the outcomes of 216 episodes of laboratory-confirmed pneumococcal bacteremia treated in Hong Kong between 1995 and 2001 were assessed. The patients had a mean age (+/-standard deviation) of 40+/-33.7 years. In all patients, the clinical diagnosis was confirmed by isolation of Streptococcus pneumoniae from blood (n=216), cerebrospinal fluid (n=7) and/or other sterile sites (n=12). Penicillin nonsusceptibility was found in 37.5% of the isolates (20.8% intermediate and 16.7% resistant). Penicillin nonsusceptibility was not a risk factor for inpatient mortality (p=0.7), nor did it affect duration of fever (p=0.4), requirement for intensive care unit admission (p=0.4) or development of suppurative complications (p=0.2). Advanced age (OR 11.3, 95%CI 4.5-28.2, p<0.01), critical illness (OR 11.3, 95%CI 4.5-28.2, p<0.001) and discordant therapy (OR 4.3, 95%CI 1.7-10.9, p<0.002) involving agents with poor anti-pneumococcal activity (but not penicillins and broad-spectrum beta-lactam agents) were significantly associated with mortality.
    European Journal of Clinical Microbiology 05/2006; 25(5):323-7. DOI:10.1007/s10096-006-0139-6 · 2.67 Impact Factor
  • J. Ho · J. Mak · S. Ho · M. Ip · K. Tsang · W. Lam · M. Chan-Yeung
    Lung Cancer 07/2005; 49. DOI:10.1016/S0169-5002(05)80784-6 · 3.74 Impact Factor
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    P L Ho · Alex Y M Ho · K H Chow · River C W Wong · R S Duan · W L Ho · Gannon C Mak · Kenneth W Tsang · W C Yam · KY Yuen
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    ABSTRACT: A study was conducted to evaluate the occurrence and characterization of extended-spectrum beta-lactamases (ESBLs) among blood isolates of Proteus mirabilis collected over a 4 year period in Hong Kong. Production of ESBLs among 99 consecutive and non-duplicate isolates was evaluated by the double-disc synergy test. The ESBLs were characterized by isoelectric focusing and PCR sequencing using specific primers. The epidemiological relationship of the isolates was studied by the Dienes test and PFGE. ESBLs were identified in 13 isolates, from none in 1999-2000 and up to 18.5% (5/27) in 2001 and 25.8% (8/31) in 2002. The ESBL-producing isolates were more resistant to ceftriaxone than to ceftazidime, and were more likely than non-ESBL-producers to have resistance to ciprofloxacin (76.9% versus 14%) and gentamicin (38.5% versus 9.3%). The ESBL content included CTX-M-13 (n=8), CTX-M-14 (n=3), SHV-5 (n=2), TEM-11 (n=1), and an unidentified ESBL with a pI of 7.5. The Dienes test revealed that the genetic background in the 99 isolates was highly heterogeneous, with 54 distinct types among 92 isolates and seven were non-typeable. Among the 13 ESBL-producing isolates, five different backgrounds, including one cluster (Dienes-pulsotype A) with nine isolates, were identified by both Dienes test and PFGE, thus suggesting both clonal and multi-clonal spread of the CTX-M enzymes. Our findings indicate the emergence of CTX-M enzymes among P. mirabilis in Hong Kong. More ESBL screening of this species is required to improve their recognition.
    Journal of Antimicrobial Chemotherapy 07/2005; 55(6):840-5. DOI:10.1093/jac/dki135 · 5.44 Impact Factor
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    ABSTRACT: It has been suggested that patients with bronchiectasis might have increased central microtubular orientation angle (CMOA), which leads to poor coordination of ciliary beating, and consequently impairment of airway defence. We have employed transmission electron microscopy to assess CMOA of ciliated nasal mucosa in a cohort of 133 (81F, 56.8+/-16.1yr) stable bronchiectasis and 59 healthy subjects (30F, 49.3+/-22.1yr). There was no significant difference in CMOA between bronchiectasis (13.2 degree) and control subjects (13.0 degree, P=0.82). There was no significant difference in CMOA among patients according to the etiology of bronchiectasis, presence of nasal symptoms, or sputum status of Pseudomonas aeruginosa infection. Patients with more severe bronchiectasis, i.e. those with FEV(1) <60%, FVC <60%, or more than 4 bronchiectatic lung lobes, had significantly lower CMOA than their counterparts (P<0.05). There was no correlation between CMOA with age, 24h sputum volume, exacerbation frequency, FEV(1), FVC, or the number of bronchiectatic lung lobes (P>0.05). CMOA correlated with ciliary beat frequency (negative), and the percent of cilia showing ultrastructural or microtubular defects (P<0.05). Central microtubular orientation angle does not correlate with clinically important parameters, in contrary to the results reported by previously published smaller scale studies.
    Respiratory Medicine 04/2005; 99(3):290-7. DOI:10.1016/j.rmed.2004.08.005 · 2.92 Impact Factor
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    ABSTRACT: A total of 139 consecutive and non-duplicate bloodstream isolates of Enterobacter spp. collected from inpatients in Hong Kong during 2000-2002 were studied for production of extended-spectrum beta-lactamases (ESBLs). All isolates were evaluated by the modified double-disc synergy test (m-DDST), the combined disc method (CDM) and the three-dimensional (3D) test. The m-DDST and CDM were modified by the use of cefepime discs. beta-Lactamases were characterized by isoelectric focusing and PCR sequencing using specific primers. ESBLs were identified in nine isolates (overall 6.5%), including seven of 39 (17.9%) Enterobacter hormaechei, one of 27 (3.7%) Enterobacter aerogenes and the only Enterobacter intermedius strain. The E. intermedius strain was positive only in the 3D test but not in the other two tests. The other eight strains were positive in all three tests. No ESBL was detected in the other species, including non-hormaechei members of the Enterobacter cloacae complex (n=61), Enterobacter agglomerans (n=7), Enterobacter gergoviae (n=4) and Enterobacter sakazakii (n=1). The ESBL content included five different CTX-M enzymes (CTX-M-9, CTX-M-13, CTX-M-14, CTX-M-24 and a novel CTX-M-2-like beta-lactamase), SHV-12 (n=2) and unidentifiable ESBLs with a pI of 7.7 or 7.9 in two strains. The seven ESBL-producing E. hormaechei were genotyped by pulsed-field gel electrophoresis and were found to be unrelated to each other. In three of the CTX-M-producing strains, ISEcp1-like elements, including promoters for the beta-lactamase gene, were found. Our data underscore the diversity of CTX-M enzymes among Enterobacter spp. in Hong Kong.
    Journal of Antimicrobial Chemotherapy 04/2005; 55(3):326-32. DOI:10.1093/jac/dki010 · 5.44 Impact Factor
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    ABSTRACT: Although ciliary dysfunction and numerous ultrastructural defects have been described, and these could be etiologically important in the development of bronchiectasis, their correlation with relevant clinical parameters have not been systematically evaluated. We have prospectively evaluated the prevalence and clinical significance of ciliary beat frequency and ultrastructural defects of nasal respiratory mucosa obtained from 152 stable patients with idiopathic bronchiectasis (100F, 57.7 +/- 15.2 yrs) and 127 control subjects (58F, 56.0 +/- 24.2 yrs). Bronchiectasis patients had significantly slower ciliary beat frequency (p < 0.05), and a greater percent of patients had central and peripheral microtubular defects (OR 14.4, 95% CI 5.6-36.8), namely, extra peripheral microtubules, "9 + 1", "8 + 2", and compound cilia (p < 0.05), but not microtubular disarrangement, extra matrix or ciliary tail abnormalities (p > 0.05), than controls. Bronchiectasis patients also had a greater proportion of cilia with any ultrastructural microtubular defects, compound cilia, and ciliary tails than controls (p < 0.05). Ciliary beat frequency did not correlate with clinically relevant parameters (p > 0.05). However, the percent of cilia with central, but not peripheral, microtubular defects correlated with 24 h sputum volume (r = 0.40, p = 0.001, and r = -0.04, p = 0.70, respectively) and FEV1 (r = -0.24, p = 0.01, and r = 0.00, p = 0.99 respectively). Our results strongly suggest a pathogenic role for central microtubular defects in the development of idiopathic bronchiectasis.
    Beiträge zur Klinik der Tuberkulose 03/2005; 183(2):73-86. DOI:10.1007/s00408-004-2520-5 · 2.17 Impact Factor
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    ABSTRACT: In an outbreak of a completely new infectious disease like severe acute respiratory syndrome (SARS), estimation of the fatality rate over the course of the epidemic is of clinical and epidemiological importance. In contrast with the constant case fatality rate, a new measure, termed the ‘realtime’ fatality rate, is proposed for monitoring the new emerging epidemic at a population level. A competing risk model implemented via a counting process is used to estimate the realtime fatality rate in an epidemic of SARS. It can capture and reflect the time-varying nature of the fatality rate over the course of the outbreak in a timely and accurate manner. More importantly, it can provide information on the efficacy of a certain treatment and management policy for the disease. The method has been applied to the SARS data from the regions affected, namely Hong Kong, Singapore, Toronto, Taiwan and Beijing. The magnitudes and patterns of the estimated fatalities are virtually the same except in Beijing, which has a lower rate. It is speculated that the effect is linked to the different treatment protocols that were used. The standard estimate of the case fatality rate that was used by the World Health Organization has been shown to be unable to provide useful information to monitor the time-varying fatalities that are caused by the epidemic.
    Journal of the Royal Statistical Society Series A (Statistics in Society) 12/2004; 168(1):233 - 243. DOI:10.1111/j.1467-985X.2004.00345.x · 1.57 Impact Factor
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    ABSTRACT: Among 563 strains of Haemophilus influenzae from young children in Hong Kong, 5 (0.9%) had decreased susceptibility to quinolones. The five strains had a Ser-84-Lys or Asp-88-Asn substitution in GyrA. Pulsed-field gel electrophoresis showed that the isolates are genetically diverse.
    Emerging infectious diseases 12/2004; 10(11):1960-2. DOI:10.3201/eid1011.040055 · 7.33 Impact Factor
  • Kar Neng Lai · Kenneth W. Tsang · Wing Hong Seto · Clara G. C. Ooi
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    ABSTRACT: Severe acute respiratory syndrome (SARS) is a highly contagious and predominantly pneumonic illness caused by a novel coronavirus now commonly known as SARS-CoV. This article describes the key diagnostic clinical features, radiologic features, and investigation profiles of affected patients. We summarize our understanding from anecdotal experience and limited published data on the use of antiviral and corticosteroid therapy in the management of this highly contagious disease.
    Current Infectious Disease Reports 07/2004; 6(3):213-219. DOI:10.1007/s11908-004-0011-8
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    ABSTRACT: Adrenomedullin (AM) is a peptide involved in cardiovascular homeostasis and in inflammation. We examined its expression in a rat model of endotoxaemia. Male Sprague-Dawley rats received intraperitoneal injection of 5 or 10 mg/kg lipopolysaccharide (LPS), or saline as control. Rats were killed at 1, 3, 6, 12 and 24 h after injection. LPS at 5 mg/kg, but not saline, increased plasma AM significantly at 3 h. At 10 mg/kg, plasma AM was raised at 3, 6 and 12 h. Immunoreactive AM concentration in lung increased after 5 or 10 mg/kg LPS, but not saline. PreproAM mRNA level in lung was significantly increased at 3 and 6 h. In conclusion, endotoxin stimulates the expression of AM in the lungs and increases its circulatory concentration. AM may be involved in the systemic response to sepsis.
    Journal of Endocrinology 06/2004; 181(2):339-45. · 3.59 Impact Factor
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    B M Jones · E S K Ma · J S M Peiris · P C Wong · J C M Ho · B Lam · K N Lai · K W T Tsang
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    ABSTRACT: Severe acute respiratory syndrome (SARS) is a new disease which has spread rapidly and widely. We wished to know whether evaluation of in vitro cytokine production could contribute to improved understanding of disease pathogenesis and to better patient management. Numbers of unstimulated and mitogen-stimulated cytokine-secreting peripheral blood mononuclear cells were measured repeatedly during and after hospitalization in 13 patients with SARS using enzyme-linked immunospot technology. Numbers of interferon-gamma, interleukin (IL)-2, IL-4, IL-10 and IL-12 secreting cells induced by T cell activators were below normal in many or most patients before and during treatment with corticosteroids and ribavirin but returned essentially to normal after completion of treatment. Staphylococcus aureus Cowan 1 (SAC)-stimulated IL-10 secreting cells were increased in early SARS but fell during treatment. SAC-induced IL-12 secreting cells were deficient before, during and long after treatment. Numbers of cells induced to produce IL-6 and tumour necrosis factor-alpha by T cell or monocyte activators were higher than normal in many early SARS patients and were still increased in some during and after treatment. We conclude that prolonged dysregulated cytokine production occurs in SARS and that future studies should be directed at improving anti-inflammatory and antiviral therapies in order to limit cytokine impairment.
    Clinical & Experimental Immunology 04/2004; 135(3):467-73. DOI:10.1111/j.1365-2249.2003.02391.x · 3.28 Impact Factor
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    ABSTRACT: Severe acute respiratory syndrome (SARS) is a highly contagious and typically rapidly progressive form of atypical pneumonia, which spread from Asia to many parts of the world in early 2003. Clinical diagnosis of SARS requires the presence of unremitting fever and progressive pneumonia despite antibiotic therapy, particularly in the presence of lymphopenia and raised transaminase levels. We report the case of a woman who had undergone a successful allogeneic bone marrow transplant for acute myeloid leukemia. She presented initially with fever and a normal chest radiograph. Her indolent clinical course of SARS was punctuated by resolution of fever, but there was progressive radiologic deterioration and increasing serum antibody titer against SARS coronavirus. Treatment with oral prednisolone and ribavirin normalized her lymphopenia, altered transaminases, chest radiograph and high-resolution computed tomography appearances rapidly. Our experience should alert other clinicians in recognizing this atypical indolent presentation of SARS, to protect health care workers and the community at large and to ensure that these patients are properly treated.
    American Journal of Respiratory and Critical Care Medicine 02/2004; 169(1):125-8. DOI:10.1164/rccm.200306-754CR · 11.99 Impact Factor

Publication Stats

2k Citations
414.54 Total Impact Points

Institutions

  • 1999–2009
    • The University of Hong Kong
      • • Department of Psychology
      • • Department of Medicine
      • • Department of Diagnostic Radiology
      Hong Kong, Hong Kong
  • 1998–2008
    • Queen Mary Hospital
      Hong Kong, Hong Kong
  • 2004
    • Lands Department of The Government of the Hong Kong Special Administrative Region
      Hong Kong, Hong Kong
  • 2003
    • Queen Elizabeth Hospital
      Hong Kong, Hong Kong
    • Kwong Wah Hospital
      Hong Kong, Hong Kong
  • 1994
    • Universität Regensburg
      Ratisbon, Bavaria, Germany
  • 1993
    • National Heart, Lung, and Blood Institute
      베서스다, Maryland, United States