The ethics of randomized trials in the context of cleft palate research.
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Biomedical subjects
Publications and source records attributed to S T Lee.
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A 2,4-dinitrophenol-degrading bacterial strain, DNP505T, which was isolated from an industrial wastewater, was taxonomically studied by a polyphasic approach using phenotypic, chemotaxonomic and genetic methods. Strain DNP505T has a cell wall of chemotype IV containing meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone is MK-8(H2). Mycolic acids contain 43-53 carbon atoms. Strain DNP505T has a cellular fatty acid profile containing straight-chain saturated, unsaturated and 10-methyl-branched fatty acids and has C16:0 as the major fatty acid. The DNA G+C content is 66 mol%. Strain DNP505T formed a coherent cluster with Rhodococcus species in a phylogenetic inference based on 16S rDNA sequences. Interestingly, strain DNP505T was found to have two types of 16S rDNA sequence, which showed 10 bp sequence differences (99.3% nucleotide similarity). Its differences in some phenotypic characteristics and its genetic distinctiveness indicate that strain DNP505T is separate from Rhodococcus species described previously. It is therefore proposed that strain DNP505T should be placed in the genus Rhodococcus as a new species, Rhodococcus koreensis. The type strain of the new species is strain DNP505T (= KCTC 0569BPT = JCM 10743T).
A bacterial strain, LE31T, which is capable of degrading 3-ethylpyridine and 3-methylpyridine, was isolated from an industrial wastewater and was taxonomically studied by using a polyphasic approach. Strain LE31T was identified as a member of the genus Gordonia on the basis of chemotaxonomic characteristics and phylogenetic inference-based 16S rDNA sequence. The cell wall contained meso-diaminopimelic acid, arabinose and galactose (wall chemotype IV). The predominant menaquinone was MK-9(H2). The mycolic acids contained 47-55 carbon atoms. The major fatty acids were C16:0, C18:1 omega9c, 10-methyl-C18:0 (TBSA). The G+C content of DNA was 67 mol%. The 16S rDNA sequence of strain LE31T was most similar to that of the type strain of Gordonia rubropertincta. The differences in some phenotypic characteristics and the genetic distinctiveness distinguish strain LE31T from the Gordonia species described previously. Therefore it is proposed that strain LE31T should be placed in the genus Gordonia as a new species. The name Gordonia nitida is proposed for strain LE31T. The type strain of the new species is strain LE31T (= KCTC 0605BPT = KCCM 80004T).
The taxonomic position of a bacterial strain (PDB9T) that is capable of degrading pyridine was clarified by a polyphasic taxonomic approach using phenotypic, chemotaxonomic and genetic methods. The cells, which are rods and branched filaments during the early growth phase, fragment into short rods or cocci, thereby completing the growth cycle. Strain PDB9T was found to have a cell wall of chemotype IV, MK-8(H2) as the predominant menaquinone, mycolic acids with 36-46 carbon atoms and C16:0' C18:1 cis9, 10-methyl-C18:0 (TBSA) as the major fatty acids. The G+C content of the DNA was 66 mol%. The phylogenetic tree showed that strain PDB9T falls within an evolutionary radiation comprising Rhodococcus species and is most closely related to the type strain of Rhodococcus rhodochrous, sharing 99% 16S rDNA similarity. The differences in some phenotypic characteristics and the genetic distinctiveness distinguish strain PDB9T from the Rhodococcus species described previously. Therefore, strain PDB9T should be placed in the genus Rhodococcus as a new species, for which the new name Rhodococcus pyridinivorans sp. nov. is proposed. The type strain of the new species is strain PDB9T (= KCTC 0647BPT = KCCM 80005T).
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INTRODUCTION: Conventional management of partial thickness facial burn wounds includes the use of silver sulphadiazine dressings. Silver sulphadiazine forms an overlying slough that makes wound healing assessment difficult. Moist exposed burn ointment (MEBO) has been proposed as the ideal burn wound dressing both for burns of the face and other sites. Proponents of MEBO claim that it accelerates wound healing and results in scarless wound healing and at the same time reduce bacterial colonisation and the need for analgesics. We present here our experience with MEBO in the management of partial thickness burns of the face. MATERIALS AND METHODS: One hundred and fifteen patients with partial thickness burns were randomly assigned to conventional treatment or MEBO. Out of this, 112 were analysed. Thirty-nine patients sustained facial burns; 17 received MEBO and 22 received silver sulphadiazine. Patients were followed up daily until the burn wounds were reduced by 75% of original body surface area (BSA). RESULTS: In patients with facial burns, MEBO was similar to silver sulphadiazine therapy with respect to rate of wound healing. Minimal slough was present over the wounds in MEBO-treated wounds resulting in clearer assessment of healing progression. CONCLUSIONS: Advantages of MEBO as compared to silver sulphadiazine in the management of partial thickness burns of the face include convenient change of dressing and easier assessment of healing progression. This suggests that MEBO is a useful alternative therapy for partial thickness burns of the face.
INTRODUCTION: Cell culture and molecular technologies are basic yet sophisticated research tool used to investigate plant-based medicine for wound healing. METHODS: Cell viability and proliferation assay is used to determine whether there are any positive effects and to discover what is the limiting cytotoxic concentration in vitro. The scratch technique, fibroblast-populated collagen lattices and aortic rings embedded gels are used as the in-vitro models of wound re-epithelialization, contraction and angiogenesis. The immunofluorescence, immunoblotting and organotypic culture can be used to detect expression of specific proteins that are modulated by plant extracts during the wound healing process. MAIN FINDINGS: Given the dynamics of the wound healing process, cell culture and molecular technologies are advantageous in providing us with detailed studies and analysis of each intricate process. CONCLUSION: The scientific approaches for the study of traditional plant-based remedies for wound healing will provide us an important platform for rigorous testing and evaluation of their clinical efficacy based on accepted rules of evidence.
BACKGROUND: Anterior or posterolateral spondylodesis has been reported as a widely used surgical treatment for lumbar spondylolysis and spondylolisthesis. However, the expenditure of energy for both the physician and the patient is relatively great. The risk of complications is significant and the loss of one motion segment must be accepted. The latter is problematical, especially in young adult patients who only have symptomatic isthmic lumbar spondylolysis. METHODS: For these patients, direct repair of the defect is recommended. We used a spondylolysis hook screw and bone grafting for direct repair of the pars defect. The results were analyzed according to the clinical results and functional x-ray exams. RESULTS: The clinical results were good or excellent. The roentgenologic examinations at 6 months showed the presence of bone trabeculation across the pars defect in all cases. The physiological motion of the lumbar spine was preserved without limitation, and all of the patients had resumed daily activities or work without discomfort. CONCLUSION: There were no complications among our cases. Particularly, according to our anatomical investigations, normal structures were safe from injury as long as the proper technique was followed. A spondylolysis hook screw with bone grafting can preserve the physiological motion of the offending levels. This method is a much more physiologically appropriate surgical method for non-complicated and symptomatic lumbar spondylolysis in the young adult.
The application of deep hypothermic circulatory arrest (DHCA) as an adjutant technique in anesthetic management for surgery of giant and complex cerebral aneurysm has been clinically recognized with piling up experience in many institutes. DHCA provides the advantages such as a bloodless surgical field and protection of the brain, all of which make a precise clipping of the aneurysm possible and thus it lowers the mortality rate which could be extremely high without it. Nevertheless, in application, the disadvantages of this technique includes comparatively inefficient and uneven cooling or rewarming, severe physiological change, cardiac distension and arrhythmia during cardiopulmonary bypass (CPB), hemorrhage from systemic heparinization and brain damage due to inadequate protection, none of which has ever been stressed. Since many giant aneurysms are found inoperable during exploration with application of DHCA, it would change the fate of the patients, and the clinical value of DHCA in such an instance becomes contradictive and disputable. We would like to present our experience in a case who, because of a giant basilar aneurysm, underwent surgical correction under DHCA retrograde cerebral perfusion (RCP) with cerebral function monitoring including electroencephalography (EEG), brainstem auditory evoked potentials (BAEP), thermal diffusion cerebral blood flowmetry, study of the change of extracellular concentration of excitatory amino acid, glutamate and aspartate, and off-line neurochemical analysis with cerebral microdialysis technique.
We found that heparin at low concentrations increases the vascular endothelial growth factor (VEGF)-induced proliferation of human umbilical vein endothelial cells (HUVECs) but at high concentrations decreases it. To examine whether FLT-1, a VEGF receptor, interacts with heparin and which domain of FLT-1 binds to heparin, various extracellular domains of FLT-1 were expressed in a baculovirus/insect cell system: sFLT-1(1-7), sFLT-1(1-4), sFLT-1(1-3), and sFLT-1(1-2) containing immunoglobulin (Ig)-like loop one to seven, one to four, one to three, and one to two, respectively. The sFLT-1(1-7) and sFLT-1(1-4) readily bound heparin at the physiological salt concentration and half-dissociated from heparin at 0.65 M and 0.57 M NaCl, respectively. In contrast, the sFLT-1(1-3) and sFLT-1(1-2) poorly bound heparin at the physiological salt concentration. In addition, the interaction of sFLT-1(1-7) with heparin was not affected by EDTA up to 80 mM. We thus concluded that the fourth Ig-like loop of FLT-1 is a major heparin-binding site and divalent cations are not involved in the interaction of FLT-1 and heparin.
We raised a specific antiserum against the recombinant M2 subunit protein of ribonucleotide reductase of Leishmania mexicana amazonensis in rabbit. This antiserum was used to study the expression and cellular location of the M2 protein in wildtype as well as hydroxyurea-resistant variants (HuR) of the parasite. The protein increased with increasing dose of the drug used for selection of resistance. The increase in protein level was accompanied by an increase in the copy numbers of mRNA of the M2 gene in the variants. In contrast to mammalian cells, the M2 protein of Leishmania is located in the nucleus rather than in the cytoplasm. The number of cells expressing M2 protein is also different in mammalian cells versus Leishmania. In mammalian cells, expression of M2 protein is a strictly S-phase-correlated event and in exponentially growing cells only approximately 50% of the cells are in S-phase and only these cells synthesize M2 protein. In L. m. amazonensis, however, almost all exponentially growing cells are positive for M2 protein. This makes it unlikely that M2 protein expression in Leishmania is S-phase dependent. In view of these findings, a fresh look in the future into the regulatory mechanisms of synthesis and the site of action of RNR in L. m. amazonensis is warranted.
Bcl-2 is a key inhibitor of a broad range of apoptotic pathways, yet neither the mechanism of action nor the role of Bcl-2 subcellular localization are well understood. The subcellular localization of Bcl-2 includes the mitochondrial membrane as well as the contiguous membrane of the endoplasmic reticulum and nuclear envelope. Most studies suggest that the ability of Bcl-2 to confer cell survival is dependent upon its localization to the mitochondria. In this manuscript, we show that Bcl-2 targeted to the endoplasmic reticulum can inhibit Myc-, but not etoposide-induced apoptosis in the Rat-1 fibroblast cell line. By contrast, wild type Bcl-2 can inhibit apoptosis triggered by either death agonist. We further show both Myc and etoposide trigger disruption of mitochondrial membrane potential (MMP) and induce poly-ADP ribose polymerase (PARP) cleavage, but release of calcium was not evident. Bcl-2 abrogates apoptosis at or upstream of MMP depletion showing that Bcl-2 does not have to reside at the mitochondria to prevent apoptosis. These results further elucidate the biochemical events associated with Myc- and etoposide-induced apoptosis and significantly advance our understanding of Bcl-2 function.
Cellular ATP and rate of respiration are important for the cell survival. We have analyzed both the parameters in wild type and arsenite resistant Leishmania mexicana amazonensis. There was no significant change observed in the rate of respiration and cellular ATP content between drug resistant cells (resistance to 30 microM of sodium arsenite) and wild type cells. Further, we have tested the effect of higher concentrations (i.e. 100 microM and 500 microM) of sodium arsenite on the ATP content of the cells. An elevated level of ATP was observed only in wild type cells after short term exposure (2 h) to 100 microM of the drug, whereas, drug resistant cells initially resist with higher toxic dosage of drug (i.e. 500 microM) but failed to maintain the normal ATP level. In conclusion, respiration and ATP is not a prime event associated with drug resistance in Leishmania. Resistance to metals like arsenic and antimony in Leishmania is multifactorial events.
An extrachromosomal circular DNA of of approximately 50-kb size was amplified in the hydroxyurea-resistant variant of Leishmania mexicana amazonensis. The amplicon carried the M2 gene of ribonuleotide reductase as part of the gene encoding resistance to hydroxyurea. The amplicon was unstable. It disappeared rapidly as shown in pulse-field gradient electrophoresis gels after reversion of the cells for 20-80 days. This loss of amplified DNA was accompanied by a rapid loss of resistance to hydroxyurea during the same period. The amplicon was not hybridized to specific probes from any of the four regions of DNA amplification previously reported for Leishmania. This region of amplification thus appears to be a new region of DNA amplification in Leishmania.
Gastrointestinal hemorrhage is a known but rare complication of major burns. This case report describes the management of this potentially life threatening problem in a young adult with 45% body surface area burns who developed massive gastrointestinal-tract bleeding. The patient required a total gastrectomy that was complicated by a burst abdomen. Despite undergoing a series of major insults. the patient survived and was eventually discharged from hospital with an acceptable level of morbidity. The problems faced by the burn centre team and the issues involved in the decision making process are discussed in the management of this unusually devastating complication.
We report a case of spontaneous tension pneumocephalus which occurred 6 years after radiotherapy for a nasopharyngeal carcinoma. A skull base defect and nasocranial fistula causing tension pneumocephalus was identified, and was repaired successfully. It proved to be due to skull base osteoradionecrosis.
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A p-nitrophenol-degrading bacterial strain was isolated from industrial wastewater. This strain (NSP41T) was identified as a member of the genus Nocardioides from chemotaxonomic characterizations and phylogenetic inference based on 16S rDNA sequence analysis. The G + C content is 71.4 mol%. The diamino acid in the cell-wall peptidoglycan is LL-diaminopimelic acid. The predominant menaquinone is MK-8(H4). The cellular fatty acid profile is similar to those of Nocardioides species. 16S rDNA sequence analysis show that strain NSP41T is the most related to Nocardioides simplex strains with a level of nucleotide similarity of 98.6%. The levels of 16S rDNA similarity between strain NSP41T and other Nocardioides species ranged from 93.8 to 95.1%. This organism is distinguishable from some other Nocardioides species as well as N. simplex strains by DNA-DNA relatedness data. This organism is different from N. simplex strains in some phenotypic characteristics. Therefore, on the basis of the data presented, a new species of the genus Nocardioides, Nocardioides nitrophenolicus, is proposed. The type strain of the new species is strain NSP41T (= KCTC 0457BPT).