1.Childhood Vaccination and Childhood Exanthems
Ng Chee Lian Lawrence ; Lee Bee Wah ; Goh Lee Gan
The Singapore Family Physician 2014;40(1):18-26
The aim of vaccination is immunisation of the child against diseases to prevent mortality and morbidity from specific infections. Adequate immunization coverage is the prerequisite for creating herd immunity. The maintenance of these levels of population immunity requires continuous vigilance and changes to immunisation schedule in response to changing circumstances. Changes have been made over the years to optimise the immunisation of poliomyelitis, measles, mumps, rubella, and varicella. The introduction of hemophilus influenza type B vaccine and pneumococcal vaccine has reduced the incidence of these infections. Vaccination against human papillomavirus infection is being expanded to protect against cervical neoplasia in females and also anal intraepithelial neoplasia in both genders. Childhood exanthems due to viral and bacterial infections, as well as immunological causes continue to be important and the ability to recognise them is necessary.
3.Unexpected drug-drug interactions in human immunodeficiency virus (HIV) therapy: induction of UGT1A1 and bile efflux transporters by Efavirenz.
Lawrence S U LEE ; Paul PHAM ; Charles FLEXNER
Annals of the Academy of Medicine, Singapore 2012;41(12):559-562
INTRODUCTIONEfavirenz is an inducer of drug metabolism enzymes. We studied the effect of efavirenz and ritonavir-boosted darunavir on serum unconjugated and conjugated bilirubin, as probes for UGT1A1 and bile transporters.
MATERIALS AND METHODSHealthy volunteers were enrolled in a clinical trial. There were 3 periods: Period 1, 10 days of darunavir 900 mg with ritonavir 100 mg once daily; Period 2, 14 days of efavirenz 600 mg with darunavir/ritonavir once daily; and Period 3, 14 days of efavirenz 600 mg once daily. Serum bilirubin (conjugated and unconjugated) concentrations were obtained at baseline, at the end of each phase and at exit.
RESULTSWe recruited 7 males and 5 females. One subject developed grade 3 hepatitis on efavirenz and was excluded. Mean serum unconjugated bilirubin concentrations were 6.09 μmol/L (95% confidence interval [CI], 4.99 to 7.19) at baseline, 5.82 (95% CI, 4.88 to 6.76) after darunavir/ritonavir, 4.00 (95% CI, 2.92 to 5.08) after darunavir/ritonavir with efavirenz, 3.55 (95% CI, 2.58 to 4.51) after efavirenz alone and 5.27 (95% CI, 3.10 to 7.44) at exit (P <0.01 for the efavirenz phases). Mean serum conjugated bilirubin concentrations were 3.55 μmol/L (95% CI, 2.73 to 4.36) at baseline, 3.73 (95% CI, 2.77 to 4.68) after darunavir/ritonavir, 2.91 (95% CI, 2.04 to 3.78) after darunavir/ritonavir with efavirenz, 2.64 (95% CI, 1.95 to 3.33) after efavirenz alone and 3.55 (95% CI, 2.19 to 4.90) at exit (P <0.05 for the efavirenz phases).
CONCLUSIONEfavirenz decreased unconjugated bilirubin by 42%, suggesting UGT1A1 induction. Efavirenz also decreased conjugated bilirubin by 26%, suggesting induction of bile efflux transporters. Ritonavir-boosted darunavir had no effect on bilirubin concentrations. These results indicate that efavirenz may reduce concentrations of drugs or endogenous substances metabolized by UGT1A1 or excreted by bile efflux transporters.
Adult ; Aged ; Anti-HIV Agents ; therapeutic use ; Benzoxazines ; pharmacology ; Biological Transport ; Confidence Intervals ; Darunavir ; Dose-Response Relationship, Drug ; Drug Interactions ; Enzyme Induction ; drug effects ; Female ; Glucuronosyltransferase ; biosynthesis ; blood ; HIV Infections ; drug therapy ; HIV Protease Inhibitors ; Humans ; Incidental Findings ; Male ; Membrane Transport Proteins ; drug effects ; metabolism ; Middle Aged ; Ritonavir ; pharmacology ; Sulfonamides ; pharmacology ; Young Adult
4.Mac-1-mediated Uptake and Killing of Bordetella bronchiseptica by Porcine Alveolar Macrophages.
Jong Keuk LEE ; Lawrence B SCHOOK ; Mark S RUTHERFORD
Journal of Veterinary Science 2003;4(1):41-49
The role of Mac-1 as a receptor for Bordetella bronchiseptica infection of alveolar macrophages (AMphi) was examined using 6 strains (2 ATCC and 4 pathogenic field isolates) to assess B. bronchiseptica binding, uptake and replication in primary porcine AMphi. All B. bronchiseptica strains were rapidly killed by porcine serum in a dose- and time-dependent manner. However, heat-inactivated porcine serum (HIS) did not demonstrate any bacterial-killing activity, suggesting that complement may have a direct killing activity. All field isolates were more resistant to direct complement-mediated B. bronchiseptica killing. The uptake of B. bronchiseptica into AMphi was inhibited approximately 50% by antiMac-1 monoclonal antibodies in the medium. However, B. bronchiseptica phagocytosed in the presence of serum or HIS was not altered by anti-Mac-1 antibodies although more bacteria were internalized by addition of serum or HIS. These data suggest that Mac-1 is a target for direct uptake of B. bronchiseptica via opsoninindependent binding. The phagocytosed B. bronchiseptica, either via direct or serum-mediated binding, were efficiently killed by AMphi within 10 hr postinfection. This demonstrates that Mac-1-mediated B. bronchiseptica uptake is a bacterial killing pathway not leading to productive infections in AMphi.
Animals
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Antibodies, Bacterial/blood/immunology
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Bordetella bronchiseptica/*immunology
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Macrophage-1 Antigen/*immunology
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Macrophages, Alveolar/*immunology
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Phagocytosis
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Protein Binding
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Swine/*immunology/*microbiology
6.Different Managements for Esophageal Epithelial Neoplasms between the Japanese, Singaporean, and Korean Endoscopists.
Sun Young LEE ; Kenjiro YASUDA ; Ichiro YASUDA ; Lawrence Ky HO ; Su Young AHN ; Tae Yoon LEE ; Chan Sup SHIM
The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2011;11(1):59-64
BACKGROUND/AIMS: There are controversies for the management of esophageal neoplasia due to its variety among countries. In this study, we tried to uncover the different managements on esophageal neoplasia between Korea, Singapore, and Japan. MATERIALS AND METHODS: We administered ten questionnaires to Korean, Japanese, and Singaporean endoscopists. The questionnaire consisted of endoscopic images from ten different esophageal neoplasms. RESULTS: For Barrett esophagus (BE) with adenocarcinoma (P=0.013) and well-differentiated- type squamous cell carcinoma (P=0.007), all (100%) of the Japanese endoscopists selected endoscopic resection as treatment, whereas 25~40% of the Korean and Singaporean endoscopists selected surgical resection. For BE with low grade dysplasia (P=0.002) and flat-type squamous dysplasia (P<0.001), observation without endoscopic treatment was preferred in Japan, whereas endoscopic treatment was preferred in Korea and Singapore. Similar findings between three countries were; (i) medication for BE, (ii) endoscopic treatment for BE with high grade dysplasia and elevated-type squamous dysplasia, and (iii) operation for moderately-differentiated or poorly-differentiated typed SCC. CONCLUSIONS: Our survey addresses different managements on esophageal neoplasia between Korea, Singapore, and Japan. More advanced or aggressive treatments are preferred in Korea and Singapore than in Japan for the management of BE with LGD, flat-type squamous dysplasia, BE with adenocarcinoma, and WD-typed SCC.
Adenocarcinoma
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Asian Continental Ancestry Group
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Barrett Esophagus
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Carcinoma, Squamous Cell
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Esophageal Neoplasms
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Humans
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Japan
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Korea
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Neoplasms, Glandular and Epithelial
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Singapore
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Surveys and Questionnaires
7.Immunosuppression by T regulatory cells in cows infected with Staphylococcal superantigen.
Byoung Sun CHANG ; Gregory A BOHACH ; Sang Un LEE ; William C DAVIS ; Lawrence K FOX ; Witold A FERENS ; Keun Seok SEO ; Hye Cheong KOO ; Nam Hoon KWON ; Yong Ho PARK
Journal of Veterinary Science 2005;6(3):247-250
Our recent study has provided that the in vitro SEC-induced proliferation of bovine T cells is preceded by a period of a non-proliferative immunoregulation of T cells that may be associated with cytokine production regulated by type 1 or type 2 T cells. Inversion of CD4+:CD8+ T cell ratio and induction of CD8+T cells with immunoregulatory activity could increase the probability of intracellular survival of Staphylococcus aureus (S. aureus). The increase of activated CD8+(ACT2+ BoCD8+) T cells in cows with mastitis caused by S. aureus may be associated with immune-regulatory function in the bovine mammary gland. The difference and similarity between bovine activated CD8+ T cells (CD8+ CD26+)and well-established human CD4+ CD25+ T regulatory (Tr)cells may help to reveal their unique immune regulatory system in the host infected with S. aureus.
Animals
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Cattle
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Cell Proliferation
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Female
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Lymphocyte Activation/immunology
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Mastitis, Bovine/*immunology/microbiology
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Staphylococcal Infections/immunology/*veterinary
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Staphylococcus/*immunology
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*Superantigens
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T-Lymphocytes/*immunology
8.Radiobiological mechanisms of stereotactic body radiation therapy and stereotactic radiation surgery.
Mi Sook KIM ; Wonwoo KIM ; In Hwan PARK ; Hee Jong KIM ; Eunjin LEE ; Jae Hoon JUNG ; Lawrence Chinsoo CHO ; Chang W SONG
Radiation Oncology Journal 2015;33(4):265-275
Despite the increasing use of stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS) in recent years, the biological base of these high-dose hypo-fractionated radiotherapy modalities has been elusive. Given that most human tumors contain radioresistant hypoxic tumor cells, the radiobiological principles for the conventional multiple-fractionated radiotherapy cannot account for the high efficacy of SBRT and SRS. Recent emerging evidence strongly indicates that SBRT and SRS not only directly kill tumor cells, but also destroy the tumor vascular beds, thereby deteriorating intratumor microenvironment leading to indirect tumor cell death. Furthermore, indications are that the massive release of tumor antigens from the tumor cells directly and indirectly killed by SBRT and SRS stimulate anti-tumor immunity, thereby suppressing recurrence and metastatic tumor growth. The reoxygenation, repair, repopulation, and redistribution, which are important components in the response of tumors to conventional fractionated radiotherapy, play relatively little role in SBRT and SRS. The linear-quadratic model, which accounts for only direct cell death has been suggested to overestimate the cell death by high dose per fraction irradiation. However, the model may in some clinical cases incidentally do not overestimate total cell death because high-dose irradiation causes additional cell death through indirect mechanisms. For the improvement of the efficacy of SBRT and SRS, further investigation is warranted to gain detailed insights into the mechanisms underlying the SBRT and SRS.
Antigens, Neoplasm
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Cell Death
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Humans
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Radiobiology
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Radiotherapy
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Recurrence
9.The Alpha-2A Adrenergic Receptor Gene -1291C/G Single Nucleotide Polymorphism is Associated with the Efficacy of Methylphenidate in Treating Taiwanese Children and Adolescents with Attention-Deficit Hyperactivity Disorder.
Hui Ching HUANG ; Lawrence Shih Hsin WU ; Shun Chieh YU ; Bo Jian WU ; Ahai Chang LUA ; Shin Min LEE ; Chao Zong LIU
Psychiatry Investigation 2018;15(3):306-312
OBJECTIVE: The therapeutic effect of methylphenidate (MPH) in treating attention-deficit/hyperactivity disorder (ADHD) has been related to the alpha-2A adrenergic receptor (ADRA2A) gene -1291C/G single nucleotide polymorphism (SNP). We investigated the effect of MPH in treating Taiwanese children and adolescent with ADHD and its relation to the ADRA2A gene -1291C/G SNP. METHODS: The subjects with DSM-IV ADHD diagnosis underwent a titration period to find out the dose of MPH for maintenance treatment. After 4 weeks maintenance treatment, the effect of MPH was evaluated by the Swanson, Nolan and Pelham version IV total scores. The subjects with more than 25% score reduction were referred to responders and those with ≥50% improvement were considered as better responders. The -1291C/G variant of the ADRA2A gene was identified by DNA sequencing and what relevance it has to the MPH response was examined by binary logistic regression analysis. RESULTS: Of the 59 subjects, 44 (74.6%) were responsive to MPH treatment and the responsiveness was not shown to be associated with the ADRA2A gene -1291C/G SNP. As the responsive subjects were categorized as moderate responders and better responders and subjected to statistical analysis, the GG homozygotes showed a greater chance to have a better response to MPH treatment than CC homozygotes (p=0.02), with an odds ratio of 32.14 (95% CI=1.64–627.80). CONCLUSION: The ADRA2A gene -1291C/G SNP is associated with the efficacy of MPH for the treatment of ADHD in Taiwanese children and adolescents. The responsive subjects bearing homozygous -1291G allele are more likely to have a better response to MPH treatment.
Adolescent*
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Alleles
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Child*
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Diagnosis
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Diagnostic and Statistical Manual of Mental Disorders
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Homozygote
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Humans
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Logistic Models
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Methylphenidate*
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Odds Ratio
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Pharmacogenetics
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Polymorphism, Single Nucleotide*
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Receptors, Adrenergic, alpha-2*
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Sequence Analysis, DNA
10.Modulation of Pituitary Somatostatin Receptor Subtype (sst1-5) mRNA Levels by Growth Hormone (GH) -Releasing Hormone in Purified Somatotropes.
Seungjoon PARK ; Heesoon PARK ; Mina LEE ; Sookjin SOHN ; Eunhee KIM ; Jeechang JUNG ; Lawrence A FROHMAN ; Rhonda D KINEMAN
The Korean Journal of Physiology and Pharmacology 2003;7(2):79-84
We have previously reported that expression of the somatostatin receptor subtypes, sst1-5, is differentially regulated by growth hormone (GH) -releasing hormone (GHRH) and forskolin (FSK), in vitro. GHRH binds to membrane receptors selectively located on pituitary somatotropes, activates adenylyl cyclase (AC) and increases sst1 and sst2 and decreases sst5 mRNA levels, without significantly altering the expression of sst3 and sst4. In contrast FSK directly activates AC in all pituitary cell types and increases sst1 and sst2 mRNA levels and decreases sst3, sst4 and sst5 expression. Two explanations could account for these differential effects: 1) GHRH inhibits sst3 and sst4 expression in somatotropes, but this inhibitory effect is masked by expression of these receptors in unresponsive pituitary cell types, and 2) FSK inhibits sst3 and sst4 expression levels in pituitary cell types other than somatotropes. To differentiate between these two possibilities, somatotropes were sequentially labeled with monkey anti-rat GH antiserum, biotinylated goat anti-human IgG, and streptavidin-PE and subsequently purified by fluorescent-activated cell sorting (FACS). The resultant cell population consisted of 95% somatotropes, as determined by GH immunohistochemistry using a primary GH antiserum different from that used for FACS sorting. Purified somatotropes were cultured for 3 days and treated for 4 h with vehicle, GHRH (10 nM) or FSK (10micrometer). Total RNA was isolated by column extraction and specific receptor mRNA levels were determined by semi-quantitative multiplex RT-PCR. Under basal conditions, the relative expression levels of the various somatostatin receptor subtypes were sst2> sst5> sst3=sst1> sst4. GHRH treatment increased sst1 and sst2 mRNA levels and decreased sst3, sst4 and sst5 mRNA levels in purified somatotropes, comparable to the effects of FSK on purified somatotropes and mixed pituitary cell cultures. Taken together, these results demonstrate that GHRH acutely modulates the expression of all somatostatin receptor subtypes within GH-producing cells and its actions are likely mediated by activation of AC.
Adenylyl Cyclases
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Cell Culture Techniques
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Colforsin
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Goats
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Growth Hormone*
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Haplorhini
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Immunoglobulin G
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Immunohistochemistry
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Masks
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Membranes
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Receptors, Somatostatin*
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RNA
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RNA, Messenger*
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Somatostatin*