Biomedical subjects
Publications and source records attributed to S T Lee.
Medical care in developing countries may be improved by various means. Advances in the medical education and training of specialists play an important role in improving health care systems. The results of the efforts of a neurosurgeon from North America who helped establish neurosurgical training in Taiwan are reported after a follow-up period of 20 years.
Cells of Gordonia nitida LE31 grown on 3-methylpyridine degraded 3-ethylpyridine without a lag time and vice versa. Cyclic intermediates were not detected, but formic acid was identified as a metabolite. Degradation of levulinic acid was induced in cells grown on 3-methylpyridine and 3-ethylpyridine. Levulinic aldehyde dehydrogenase and formamidase activities were higher in cells grown on 3-methylpyridine and 3-ethylpyridine than in cells grown on acetate. These data indicate that 3-methylpyridine and 3-ethylpyridine were degraded via a new pathway involving C-2-C-3 ring cleavage.
PURPOSE: To examine whether the different appearances of intramedullary high signal intensity (SI) on T2-weighted MR images in cervical spondylotic myelopathy are related to differences in surgical prognosis. MATERIALS AND METHODS: The magnetic resonance (MR) findings and Japanese Orthopedic Association (JOA) score of 64 cervical spondylotic myelopathy patients, who underwent decompression surgery, were evaluated. SIs were classified as type 0 if no intramedullary high SI on T2-weighted MR images was noted, type 1 if a predominantly (>50%) faint and fuzzy border of high SI was noted, or type 2 if a predominantly (>50%) intense and well-defined border of high SI was noted. Postoperative JOA scoring and MR imaging were also performed 6 months after surgery. Recovery ratios were calculated. RESULTS: There were 20 type 0, 23 type 1, and 21 type 2 cases. Statistical analyses showed no significant difference in age, sex, cervical curvature, and preoperative JOA score between the three groups. Statistical analyses of the recovery ratio showed significantly poor prognosis of type 2 compared with type 1 (P < .001) and type 0 (P =.001), but no difference between types 0 and 1 (P = .317). After controlling for factors of age, sex, preoperative JOA score, cervical curvature, and cord compression ratio, analysis of covariance showed the same result. CONCLUSION: Type 1 intramedullary high SI on T2-weighted MR images indicates a better surgical outcome than does type 2.
Extracts from the leaves of Chromolaena odorata have been shown to be beneficial for treatment of wounds. The crude ethanol extract of the plant had been demonstrated to be a powerful antioxidant to protect fibroblasts and keratinocytes in vitro. In this study, the most active compounds were fractionated and identified from the crude extract using liquid chromatography coupled with UV spectroscopy and mass spectrometry. The antioxidant effects of purified fractions on cultured fibroblasts and keratinocytes were investigated using colorimetric and lactate hydrogenase release assay. The results showed that the phenolic acids present (protocatechuic, p-hydroxybenzoic, p-coumaric, ferulic and vanillic acids) and complex mixtures of lipophilic flavonoid aglycones (flavanones, flavonols, flavones and chalcones) were major and powerful antioxidants to protect cultured skin cells against oxidative damage. In conclusion, the extract from C odorata contains a mixture of powerful antioxidant compounds that may be one of potential mechanism contributing to enhanced wound healing.
The purpose of this study was to evaluate the feasibility and efficacy of autologous transplantation of peripheral blood stem cells (PBSC) mobilized with high-dose consolidation chemotherapy and granulocyte colony-stimulating factor in patients with acute myelogenous leukemia (AML). Twenty patients received myeloablative chemotherapy or chemo-radiotherapy including total body irradiation followed by the infusion of PBSC. PBSC were collected by large-volume leukaphereses. The mean number of mononuclear cells and CD34-positive cells infused were 7.2 x 10(8)/kg (range, 2.2-16.6), and 6.6 x 106/kg (range, 2.1-27.7), respectively. Engraftment failure was not seen in the enrolled patients. The median time to neutrophil (> or = 500/microL) and platelet recovery (> or = 50,000/microL) from the transplant was 12 days (range, 8-20) and 28 days (range, 10-600), respectively. The 2-year probability of disease-free survival (DFS) and relapse were 43% and 57% for patients with AML transplanted in first complete remission (CR1). The outcome of the patients transplanted in the advanced status was significantly worse than the patients transplanted in CR1 (P=0.04). Most relapses occurred within 1 year after transplantation. Fatal hepatic veno-occlusive disease was observed in one case. Other transplantation-related toxicities were mild. Our results demonstrated that autologous transplantation of high-dose consolidation chemotherapy-mobilized peripheral blood progenitor cells is feasible in the patients with AML in CR1. To further reduce the risk of leukemia relapse, much effort should be contributed to the field of ex vivo purging and post-transplant immunotherapy.
BACKGROUND: Provoked by the limitations and late complications of levodopa therapy, the advances in stereotactic surgery, and better understanding of the pathophysiology of the basal ganglia, the role of pallidotomy in the treatment of advanced Parkinson's disease (PD) has been revived. METHODS: We included 11 patients with advanced PD, who had a good response to levodopa but had late complications of motor fluctuation and severe dyskinesia. The internal globus pallidus was identified with computed tomography prior to posteroventral pallidotomy and it was reaffirmed by microelectrode recording during surgery. Clinical evaluations were carried out in both the "on" and "off" motor periods at baseline and at 1 week, 3 months, 6 months and 1 year postoperatively. Repeated measures ANOVA followed by multiple comparisons were used for statistical analysis. RESULTS: Dyskinesia improved bilaterally but only significantly in the contralateral limbs. This benefit was sustained up to 1 year. Parkinsonism, particularly contralateral tremor and rigidity, improved in the "off" motor period but not in the "on" motor period. The average Unified Parkinson's Disease Rating Scale motor score was reduced 36% at 3 months and 26% at 1 year in the "off" motor period. Both of the mean Hoehn and Yahr staging and Schwab and England activities of daily living score improved in "off" motor period. Improvement in parkinsonism, however, did not reach a significant level. Mild dysarthria and unstable gait were observed temporarily in 2 patients. Mild weakness in the contralateral limbs was found in 1 patient. CONCLUSIONS: Unilateral pallidotomy guided by microelectrode recording is helpful for severe levodopa-induced dyskinesia in advanced PD. Contralateral parkinsonian disabilities also improve in the "off" motor period.
Switchgrass (Panicum virgatum L.) has been reported to be hepatotoxic, causing photosensitization in lambs and horses. In this study we show the presence of steroidal saponins in two samples of switchgrass that has been implicated in the poisonings of sheep and horses. After hydrolysis of the saponins, diosgenin was determined to be the major sapogenin in both switchgrass samples. We also confirmed the presence of diosgenin in kleingrass after hydrolysis of saponins extracted from it.
Candida species are low virulence organisms which inhabit the skin and mucous membranes of most individuals. There has been increasing incidence of disseminated and deep-seated Candida infections owing to the increasing number of immune compromised hosts. However, the Candida species are still rarely suggested as causative pathogens of vertebral osteomyelitis. We present a 51-year-old man with neck pain and cervical radiculopathy. Three months prior to visiting our hospital, he had undergone a urological operation which was complicated by a urinary tract infection. Magnetic resonance imaging and X-rays showed erosion of the body of the 5th cervical spine and collapse of the C5-C6 disc. After open debridement, tissue pathology results revealed Candida infection. Clinical stability was achieved during the 6-month follow-up period with a combination of amphotericin B and posterior fixation method. We reviewed the literature and found a high rate of surgical intervention for patients suggested of having Candida vertebral osteomyelitis. However, the surgical intervention may not be necessary. Early diagnosis using noninvasive percutaneous needle biopsy may help reduce the incidence of delayed treatment.
This study reports the unique compartmentalization of cortisol and 11-deoxycortisol biosynthesis in vitro from [(3)H]17alpha-hydroxyprogesterone (17P) in testicular tissues of groupers after sex inversion induced by 17alpha-methyltestosterone (MT). Before MT implantation, the ovarian tissues produced only nonpolar metabolites. Following sex inversion some 6 months later, synthesis of these nonpolar metabolites was not detectable. Instead, cortisol and 11-deoxycortisol, with yields of about 3% and 14%, respectively, were synthesized together with two other polar metabolites. The corticosteroids and polar metabolites were distinctly nondetectable in ovarian tissues of the control fish throughout the experiment. While the significance of this testicular synthesis of corticosteroids is presently unclear, it could be related to the increased energy demands arising from the reorganization of gonadal tissues during sex inversion.
Here we report the inhibition of cellular invasion by a recombinant mouse endostatin and the possible mechanism of the inhibition. Endostatin significantly reduced endothelial as well as tumor cellular invasion into the reconstituted basement membrane in vitro. Gelatin zymographic analysis revealed that the activation of promatrix metalloproteinase-2 (proMMP-2) that was secreted from endothelial cells was blocked upon endostatin treatment. Studies with recombinant MMPs confirmed that endostatin inhibited proMMP-2 activation, mediated by both membrane-type 1 MMP and 4-aminophenylmercuric acetate. Furthermore, enzymatic assays using a peptide substrate demonstrated that endostatin inhibited the catalytic activities of both MMP-2 and membrane-type 1 MMP. Finally, coimmunoprecipitation experiments revealed that endostatin formed a stable complex with proMMP-2. These novel findings would, at least in part, explain the mechanism of the potent antiangiogenic and antitumor activities of endostatin.
Membrane-type 1 matrix metalloproteinase (MT1-MMP; MMP14) is known to activate pro-matrix metalloproteinase-2 (pro-MMP-2; progelatinase A) on the cell surface. To analyse the tissue inhibitor of metalloproteinases-2 (TIMP-2) effect on activation of pro-MMP-2 by MT1-MMP, we have expressed the full-size MT1-MMP (fMT1-MMP) and a transmembrane (TM)-domain-deleted soluble MT1-MMP (sMT1-MMP) in the baculovirus/Sf9 (Spodoptera frugiperda 9) insect-cell system, where neither endogenous gelatinolytic MMPs nor TIMP-2 are expressed. Both fMT1-MMP and sMT1-MMP expressed in the expression system were found not to contain the pro-domain and were able to activate the TIMP-2-free pro-MMP-2. Both in the insect cells and in vitro, activation of pro-MMP-2 by fMT1-MMP was enhanced at low concentrations of TIMP-2 and inhibited by its higher concentrations. The maximal enhancing effect was detected at 0.05 molar fraction of TIMP-2/fMT1-MMP. In contrast, activation of pro-MMP-2 by sMT1-MMP was dose-dependently inhibited by TIMP-2. These results demonstrate that the TM domain of MT1-MMP is not required for the ability to activate pro-MMP-2, but is required for the enhancing effect of TIMP-2 on pro-MMP-2 activation by recruiting pro-MMP-2 to the MT1-MMP-TIMP-2 complex as a cell-surface pro-MMP-2 receptor. Moreover, our data strongly suggest that the pro-domain of MT1-MMP is not required for the TIMP-2-mediated enhancing effect on pro-MMP-2 activation. In addition, the pro-MMP-2 in the MT1-MMP-TIMP-2-pro-MMP-2 ternary complex was not activated without external activator, but readily by addition of sMT1-MMP. This result demonstrates that MT1-MMP free of TIMP-2 would be the enzyme responsible for activation of the pro-MMP-2 in the ternary complex under physiological conditions.
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Larkspur (Delphinium spp.) poisons thousands of cattle on western rangelands each year. Because poisoning does not cause specific lesions, and poisoned animals are rarely found before they die, definitively identifying poisoned animals is difficult. Additionally, toxin concentrations in larkspur plants vary with environment, plant, and location. Rapid, sensitive, and specific diagnostic techniques are needed to identify poisoned animals and to determine when and what plants are likely to poison livestock. In this study, three competitive inhibition enzyme-linked immunosorbent assays (CI-ELISA) for toxic larkspur alkaloids were developed. One assay is class-specific toward the N-(methylsuccinimido)anthranoyllycoctonine (MSAL) alkaloids, and two assays are specific for individual alkaloids. The assay with the lowest limit of detection had an I(50) of 191 pg with a limit of detection of 30.5 pg for methyllycaconitine. Spike and recovery studies using bovine blood and brain tissue ranged from 52 to 89%. These findings suggest that with additional development these techniques are likely to be excellent tools for diagnosing poisoned animals and identifying highly toxic plants.
Three new N-(methylsuccinimido)anthranoyllycoctonine norditerpenoids, given the names bearline (1), 14-acetylbearline (2), and 16-deacetylgeyerline (3), were isolated from the extract of the low larkspur Delphinium nuttallianum. The structures of the individual alkaloids were determined by (1)H and (13)C NMR spectroscopy and HRMS. These alkaloids are structurally related to the neurotoxic alkaloid methyllycaconitine (4) and may be important in establishing the toxicity of low larkspurs to cattle. A mouse bioassay was used to measure the LD(50) values for two of the new alkaloids (1 and 2), as sufficient quantities of 3 were not available for toxicity testing. A structurally related alkaloid, geyerline (7), was isolated from D. geyeri in sufficient quantities for toxicity testing. The toxicities of 1, 2, and 7 were found to be comparable to that of 4, with calculated LD(50) values in mice of 5.7, 3.3, and 6.2 mg/kg, respectively.
The effect of the presence of an alternate toxic compound (phenol) on the p-nitrophenol (PNP)-degrading activity of freely suspended and calcium alginate immobilized Nocardioides sp. NSP41 was investigated. In the single substrate experiments, when the concentration of phenol and PNP was increased to 1400 mg l(-1) and 400 mg l(-1), respectively, the initial cell concentrations in the freely suspended cell culture should be higher than 1.5 g dry cell weight l(-1) for complete degradation. In the simultaneous degradation experiment, when the initial concentration of phenol was increased from 100 to 400 mg l(-1), the specific PNP degradation rate at the concentration of 200 mg l(-1) was decreased from 0.028 to 0.021 h(-1). A freely suspended cell culture with a high initial cell concentration resulted in a high volumetric degradation rate, suggesting the potential use of immobilized cells for simultaneous degradation. In the immobilized cell cultures, although simultaneous degradation of PNP and phenol was maintained, the specific PNP and phenol degradation rate decreased. However, a high volumetric PNP and phenol degradation rate could be achieved by immobilization because of the high cell concentration. Furthermore, when the immobilized cells were reused in the simultaneous degradation of PNP and phenol, they did not lose their PNP- and phenol-degrading activity for 12 times in semi-continuous cultures. Taken together, the use of immobilized Nocardioides sp. NSP41 for the simultaneous degradation of PNP and phenol at high concentrations is quite feasible because of the high volumetric PNP and phenol degradation rate and the reusability of immobilized cells.
HLA-DM has been known to be largely absent from the cell surface of antigen-presenting cells, accumulating instead in the intracellular compartment. In this study, we demonstrated that a population of HLA-DM-positive (HLA-DM+) dendritic cells (DCs) can be identified in an in vitro culture of CD34+ bone marrow haematopoietic stem cells. CD34+ bone marrow cells of healthy donors were used to generate DCs with the recombinant human cytokines granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor alpha (TNF-alpha) and stem cell factor (SCF), both with and without interleukin 4 (IL-4). Flow cytometric analysis demonstrated that HLA-DM+ cells comprised 2.5 +/- 0.9% and 1.8 +/- 0.4% of the CD34+ cell-derived progeny in the presence of GM-CSF, TNF-alpha and SCF after 7 d and 14 d of culture respectively. The number of HLA-DM molecules expressed per HLA-DM+ cell on d 7 was significantly higher than that on d 14 (1410 +/- 47 versus 370 +/- 25, P < 0.05). The addition of IL-4 to the cytokines from the commencement of culture increased the proportion of HLA-DM+ cells and increased the number of HLA-DM molecules per HLA-DM+ cell significantly (P < 0.05). Although most of the HLA-DM+ cells expressed CD1a, CD80 or CD86 antigen, only a small proportion of CD1a+, CD80+ or CD86+ cells expressed HLA-DM. About half the HLA-DM+ cells expressed CD83. The addition of IL-4 resulted in a decrease in the expression of CD83 on the HLA-DM+ cells on d 7. Microscopic evaluations of sorted HLA-DM+ cells revealed the characteristic morphological features of DCs. Primary mixed lymphocyte cultures demonstrated that the HLA-DM+ cells elicited a vigorous proliferation of allogeneic T cells. The level of antigen-specific T-cell activation induced by antigen-pulsed, chloroquine-treated HLA-DM+ cells was substantially higher than that induced by HLA-DM- cells (P < 0.05). These results show that HLA-DM can be used as a useful DC lineage-specific marker, as well as a tool for the characterization of DCs and human immunotherapy.
The Oriental nose, which has been broadly classified as mesorrhine, differs in anatomy and morphology from other racial groups. The objective of this study is to carry out anthropometric measurements in the nose region, in order to establish norms for the Oriental nose and also to identify the variations that might occur within this group. Knowledge of the unique shape, anatomy and dimensions of the Oriental nose would be very useful for surgeons undertaking repair and reconstruction of Oriental noses. Ninety, normal Oriental subjects were scanned using a laser surface scanner, and the assessments were then carried out on the laser scan images. The 3-D laser scan images permit adjustment and positioning to achieve the correct standard views for assessment. Subjective assessment of the nose shape, as well as linear and angular measurements were carried out. Depending on the fullness and roundness of the nasal tip and the prominence of the alar lobules on either side, the Oriental nasal base may take on varied shapes and accordingly, three distinct shapes have been identified. They have been classified into types A, B and C where type A has a very prominent alar lobule and a full and rounded nasal tip. In type B, the alar lobule was less prominent and the nasal tip was more defined while in type C the alar lobule was the least prominent resulting in the lateral walls forming a relatively straight slope from the tip to the alar base. The linear and angular measurements for Oriental noses were also obtained and compared to values for other racial groups. The proportion indices for the Oriental nose showed that it was broader in relation to the nose height, and had less tip protrusion in relation to both the height and width of the nose. The data collected from this study can be used as norms for Oriental cases and the simple classification of the nose shape will serve as a guide for quick reference, when planning aesthetic or reconstructive rhinoplasties for the Oriental patient.
BACKGROUND: The technique of percutaneous catheterization of the subclavian vein by the infraclavicular approach is dependent on the location of the subclavian vein in relation to the clavicle. The purpose of this study was to analyze the anatomic relationship between these two structures and how it is influenced by changes in shoulder positioning. METHODS: Dissections of the infraclavicular region were performed in seven fresh cadavers and linear measurements made to determine the extent of overlap between the vein and the clavicle in different shoulder positions. RESULTS: When the shoulder was in neutral position, the subclavian vein was overlapped by the medial third or more of the clavicle and this segment of bone was able to serve as a landmark for the vein. However, shoulder elevation displaced the clavicle cephalad and reduced the degree of overlap. Mild shoulder retraction increased the area of contact between the vein and the undersurface of the clavicle, whereas protraction lifted the clavicle off the vein. CONCLUSION: Infraclavicular subclavian venipuncture should be performed with shoulders in a neutral position and also in slight retraction. An appreciation of the anatomic relationship between the clavicle and the subclavian vein is the key to successful execution of this technique.