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Biomedical subjects

S Lee

Publications and source records attributed to S Lee.

At least 433 records · Page 24Linked to original sources
PubMed2000

Teflon granuloma after microvascular decompression for trigeminal neuralgia.

BACKGROUND: Our purpose was to research the factors that may induce Teflon granuloma in trigeminal neuralgia patients who have undergone microvascular decompression (MVD) procedures, to propose methods for the early diagnosis of Teflon granuloma, and provide suggestions for reducing this complication. METHODS: From 1985 to 1996, 89 trigeminal neuralgia patients underwent MVD with Teflon felt to separate the offending vessels and the trigeminal nerve. Ten patients had secondary explorations for recurrent symptoms. Five patients developed recurrent facial pain associated with facial numbness within a certain period after the first operation. We reviewed the onset and site of the initial symptoms, the duration of the symptoms, the operative findings and methods, and the results of the operations. In the reoperative patients, we analyzed the initial and secondary symptoms after the first operation, and the time to relapse. We compared the operative findings and methods in these operations. RESULTS: The operative findings in the 10 patients with recurrence were Teflon granuloma in five patients, arterial loop compression in three patients, venous compression in one patient, and negative exploration in one patient. The Teflon granuloma patients all complained of facial numbness after the first MVD operation. The incidence of Teflon granuloma after MVD was 5.6% (5/89). CONCLUSION: The Teflon felt used in the MVD procedure can produce complications. It is not absolutely inert when used in MVD procedures. When it contacts the tentorium and/or dura, an inflammatory giant-cell foreign body reaction can be induced. In the future, we should search for other implants to replace the Teflon felt. However, until new materials are found, we suggest that the Teflon felt be kept away from the tentorium and dura and placed completely within the CSF cisterna. We can diagnose Teflon granuloma early with enhanced CT and/or MRI, especially in patients with new facial numbness symptoms after Teflon MVD procedures. The results of reexploration of Teflon granulomas are more satisfactory than a negative exploration or venous compression. We may be able to decrease the incidence of Teflon granuloma. We should be more aggressive in performing reexploration in these recurrent patients.

Adult↗
PubMed2000

Expression of the human erythrocyte glucose transporter in transitional cell carcinoma of the bladder.

OBJECTIVES: It has previously been shown that glucose uptake and use is more prevalent in carcinomas than in normal cells and tissues. We hypothesized that human erythrocyte glucose transporter (Glut-1) expression is increased in bladder transitional cell carcinoma (TCC) and that the grade of expression might correlate with the degree of malignancy. METHODS: Immunostaining of Glut-1 protein was studied in normal bladder (5 cases), benign papilloma (10 cases), superficial tumor (48 cases), and invasive tumor (31 cases) tissue. The immunoreactivity grading system used was as follows: absence of immunoreactivity in tumor cell = 0; less than 10% of the tumor cells immunoreactive = 1+; 10% to 50% of the tumor cells immunoreactive = 2+; and greater than 50% of the tumor cells immunoreactive = 3+. RESULTS: Immunostaining of Glut-1 protein was not expressed in the normal bladder or benign papilloma samples, but it was expressed in 63.0% (46 of 73) of the TCC samples. In the pattern of expression of Glut-1 protein, superficial TCC was stained focally, but invasive TCC was stained diffusely in the tumor nests. The grade of Glut-1 protein expression increased more significantly in the invasive TCC than in the superficial TCC samples (P = 0.002) and more significantly in the high nuclear grade than in the low nuclear grade samples (P = 0.007). In the superficial TCC samples, the bladder tumor recurrence rate did not significantly correlate with Glut-1 protein expression (P = 0.40). CONCLUSIONS: Our results suggest that the Glut-1 protein is not expressed in normal bladder mucosa and benign lesions, that Glut-1 protein expression is strongly associated with neoplastic progression in bladder TCC, and that Glut-1 expression does not correlate with the recurrence rate in superficial bladder TCC.

Carcinoma, Transitional Cell↗
PubMed2000

A polymerase chain reaction based method for detecting Mycoplasma/Acholeplasma contaminants in cell culture.

A detection system that utilizes a primer mixture in a nested polymerase chain reaction for detecting Mycoplasma contaminants in cell cultures is described. Primers were designed to amplify the spacer regions between the 16S and 23S ribosomal RNA genes of Mycoplasma and Acholeplasma. This detection system was able to detect 20-180 colony forming units per milliliter of sample. Eight commonly encountered Mycoplasma and Acholeplasma contaminants, which include Mycoplasma (M.) arginini, M. fermentans, M. hominis, M. hyorhinis, M. orale, M. pirum, M. salivarium, and Acholeplasma laidlawii, were consistently amplified. Mycoplasma contaminants generated a single DNA band of 236-365 base pairs (bp), whereas A. laidlawii produced a characteristic two-band pattern of 426 and 219 bp amplicons. Species identification could be achieved by size determination and restriction enzyme digestion. Minor cross-reactions were noted with a few closely related gram positive bacteria and DNA from rat cell lines. A Mycoplasma Detection Kit for detecting Mycoplasma contaminants in cell cultures has been developed based on this approach.

Acholeplasma laidlawii↗
PubMed2000

HLA-B27 transgenic mice are susceptible to collagen-induced arthritis: type II collagen as a potential target in human disease.

HLA-B27 is highly linked with a group of human diseases called spondyloarthropathies (SpA). Many of these disorders begin after an infection with an enterobacteria. The symptoms seen in patients with spondyloarthropathies are inflammatory pain in the spine and asymmetrical arthritis of lower limbs. Additional symptoms related to SpA include inflammation in the eyes, bowel, and skin. The autoantigen(s) in SpA are not known. Proteins such as collagen and proteoglycans have been thought to be potent autoantigens in arthritidis including B27-associated human diseases. Type II collagen is a common denominator among eyes and joints, affected tissues in B27-linked diseases. Moreover, a few reports indicated CII specific T cells and antibodies in patients with spondyloarthropathies. We and others have previously described development of spontaneous arthritis and nail disease in HLA-B27 transgenic animals. To determine whether CII may be a target antigen in the B27-linked diseases, B27 + m beta 2 m% (HLA-B27) transgenic mice lacking mouse beta 2m with and without human beta 2m) mice were immunized with type II collagen inside the barrier facility. Male HLA-B27 transgenic mice developed collagen-induced arthritis compared to transgene negative littermates or female counterparts. There was no difference in the incidence of arthritis in HLA-B27 transgenic mice with and without human beta 2m. Our data suggest that beta 2m free heavy chain of HLA-B27 may present soluble antigens such as type II collagen to trigger specific T cells contributing in the development of arthritis. Our data also suggest that CII may be a potential target antigen in the cartilage during the disease process.

Animals↗
PubMed2000

Functional and structural aspects of the Kell blood group system.

Two covalently linked proteins, Kell and XK, constitute the Kell blood group system. Kell, a 93-Kd type II glycoprotein, is highly polymorphic and carries all but 1 of the known Kell antigens, and XK, which traverses the membrane 10 times, carries a single antigen, the ubiquitous Kx. The Kell/XK complex is not limited to erythroid tissues and may have multiple physiological roles. Absence of one of the component proteins, XK, is associated with abnormal red cell morphology and late-onset forms of nerve and muscle abnormalities, whereas the other protein component, Kell, is an enzyme whose principal known function is the production of a potent bioactive peptide, ET-3.

Amino Acid Sequence↗
PubMed2000

The effect of herpesvirus infection on the expression of cell adhesion molecules on cultured human dermal microvascular endothelial cells.

Cell-mediated immune response to herpes simplex virus (HSV) may be important in the pathogenesis of herpes keratitis, erythema multiforme or Behcet's disease. We examined whether herpesvirus infection regulates the expression of cell adhesion molecules on cultured human dermal microvascular endothelial cells (HDMEC) and the regulation of T-lymphocytes binding to HDMEC. The expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), or E-selectin on HDMEC increased significantly after treatment with HSV-1, HSV-2, or measles virus on HDMEC. Anti-IL-1 alpha antibody or anti-TNF alpha antibody partially inhibited the expression of ICAM-1, VCAM-1, or E-selectin on HDMEC. The binding of T-lymphocytes to HDMEC increased significantly after the treatment of HSV-1 or measles virus on HDMEC. The binding of T-lymphocytes to HDMEC was significantly inhibited after 16 h of incubation following treatment with anti-ICAM-1 antibody, anti-IL-1 alpha antibody or anti-TNF alpha antibody to HDMEC. These study results suggest that HSV induces the increased expression of ICAM-1, or induction of VCAM-1 and E-selectin on HDMEC and that among these adhesion molecules, the expression of ICAM-1 on HDMEC mainly regulates the binding of T-lymphocytes to HDMEC. The data also suggest that IL-1 alpha or TNF alpha which was produced by HSV infected HDMEC may be related to these events.

Cell Adhesion↗
PubMed2000

A computer-aided design mammography screening system for detection and classification of microcalcifications.

This paper presents a prototype of a computer-aided design (CAD) diagnostic system for mammography screening to automatically detect and classify microcalcifications (MCCs) in mammograms. It comprises four modules. The first module, called the Mammogram Preprocessing Module, inputs and digitizes mammograms into 8-bit images of size 2048x2048, extracts the breast region from the background, enhances the extracted breast and stores the processed mammograms in a data base. Since only clustered MCCs are of interest in providing a sign of breast cancer, the second module, called the MCCs Finder Module, finds and locates suspicious areas of clustered MCCs, called regions of interest (ROIs). The third module, called the MCCs Detection Module, is a real time computer automated MCCs detection system that takes as inputs the ROIs provided by the MCCs Finder Module. It uses two different window sizes to automatically extract the microcalcifications from the ROIs. It begins with a large window of size 64x64 to quickly screen mammograms to find large calcified areas, this is followed by a smaller window of size 8x8 to extract tiny, isolated microcalcifications. Finally, the fourth module, called the MCCs Classification Module, classifies the detected clustered microcalcifications into five categories according to BI-RADS (Breast Imaging Reporting and Data System) format recommended by the American College of Radiology. One advantage of the designed system is that each module is a separate component that can be individually upgraded to improve the whole system. Despite that it is still is a prototype system a preliminary clinical evaluation at TaiChung Veterans General Hospital (TCVGH) has shown that the system is very flexible and can be integrated with the existing Picture Archiving and Communications System (PACS) currently implemented in the Department of Radiology at TCVGH.

Algorithms↗
PubMed2000

Photomechanical drug delivery into bacterial biofilms.

PURPOSE: To investigate whether photomechanical waves generated by lasers can increase the permeability of a biofilm of the oral pathogen Actinomyces viscosus. METHODS: Biofilms of Actinomyces viscosus were formed on bovine enamel surfaces. The photomechanical wave was generated by ablation of a target with a Q-switched ruby laser and launched into the biofilm in the presence of 50 microg/ml methylene blue. The penetration depth of methylene blue was measured by confocal scanning laser microscopy. Also, the exposed biofilms were irradiated with light at 666 nm. After illumination, adherent bacteria were scraped and spread over the surfaces of blood agar plates. Survival fractions were calculated by counting bacterial colonies. RESULTS: Confocal scanning laser microscopy revealed that a single photomechanical wave was sufficient to induce a 75% increase in the penetration depth of methylene blue into the biofilm. This significantly increased the concentration of methylene blue in the biofilm enabling its photodestruction. CONCLUSIONS: Photomechanical waves provide a potentially powerful tool for drug delivery that might be utilized for treatment of microbial infections.

Actinomyces viscosus↗
PubMed2000

The variability of phenomenology in anorexia nervosa.

OBJECTIVE: To study the variability of phenomenology in Chinese patients with anorexia nervosa in Hong Kong. METHOD: Longitudinal case studies of four patients. RESULTS: The anorexic illness was not uniformly about the fear of fatness. Rather, patients' explanations for food refusal could change over time. A typology of anorexic phenomenology emerged; namely, fat phobic type I (fat phobia consistently present), fat phobic type II (fat phobia changing to non-fat phobic presentation), non-fat phobic type I (consistently non-fat phobic) and non-fat phobic type II (non-fat phobic initially, but fat phobic later). CONCLUSION: The variability of anorexic phenomenology challenges the current fat phobia paradigm and has implications on the diagnosis, treatment and psychometric assessment of eating disorders.

Adolescent↗
PubMed2000

Prevention of autoimmune hearing loss in MRL/lpr mice by bone marrow transplantation.

We examined the effects of bone marrow transplantation (BMT) on immune-mediated inner ear diseases in MRL/Mp-lpr/lpr (MRL/lpr) mice, which manifest not only lupus nephritis but also sensorineural hearing loss (SNHL) at the age of 20 weeks. These mice were treated with cyclophosphamide (CY) and irradiation (5 Gy x 2), followed by the transplantation of bones plus bone marrow cells from allogeneic normal C57BL/6 mice at the age of 12 weeks. Hematolymphoid cells were reconstituted with donor-derived cells 3 months after BMT. Thus-treated MRL/lpr mice showed neither lupus nephritis nor SNHL even 24 weeks after BMT. No pathological findings were observed in either glomeruli or cochleae. These findings suggest that BMT can be used to prevent the development of autoimmune SNHL in MRL/lpr mice.

Animals↗
PubMed2000

Duration of second complete remission compared with first complete remission in patients with acute myeloid leukemia. Eastern Cooperative Oncology Group.

The prognosis for patients with acute myeloid leukemia in first relapse is generally poor. The ability to induce a second complete remission (CR) with the same chemotherapy used in initial induction therapy is limited. Remission inversion rate, defined as achieving a longer second CR than the first CR in response to standard chemotherapy for relapse, is important in assessing studies of novel chemotherapy or immunologic treatment strategies for patients with relapsed disease. One hundred and twenty-four patients entered on two Eastern Cooperative Oncology Group (ECOG) studies for patients with relapsed AML were analyzed to determine the remission inversion rate. Twenty-two of the 124 patients (18%; 95% confidence interval 12-26%) experienced a longer second CR duration than the first CR duration by at least 2 months. Inversion of CR duration is thus not a rare event. The inversion frequency reported here establishes a baseline upon which future studies in relapsed disease need to be defined.

Acute Disease↗
PubMed2000

The role of IL-12 in inflammatory activity of patients with rheumatoid arthritis (RA).

The aim of this study was to investigate the role of IL-12 in patients with RA. IL-12 (p70) and its associated cytokines were measured in sera and synovial fluid (SF) using an enzyme-linked immunosorbent method. Seven American College of Rheumatology (ACR) core set measures as well as IL-12 levels were sequentially monitored at the commencement and 4 months after treatment with a low-dose steroid and disease-modifying anti-rheumatic drugs (DMARDs). In sera, 64 (42.2%) of 152 RA patients had detectable concentrations of IL-12 (p70), whereas one (1.4%) of 69 osteoarthritis (OA) patients and five (10%) of 50 healthy controls had detectable IL-12 (P < 0.001). The median level of circulating IL-12 was also higher in RA patients (P < 0.001). In SF, the number of patients with detectable IL-12 and the median IL-12 levels were significantly higher in RA patients (n = 53) than in OA patients (n = 22). In paired samples (n = 53) of sera and SF from RA patients, IL-12 levels were higher in the SF than in sera (P < 0.001). Patients with detectable IL-12 (n = 51) in sera had higher tender joint scores (P = 0.003), swollen joint scores (P < 0.001) and C-reactive protein (CRP; P = 0.036), than those without (n = 55). Four months after treatment with DMARDs, the improved group showed a larger IL-12 decrease than the non-improved group (P = 0.017). The levels of IL-12 correlated positively with those of IL-2, interferon-gamma, IL-6, and tumour necrosis factor-alpha, but were correlated inversely with those of IL-10. Our results demonstrate that IL-12 levels reflect RA disease activity and that IL-12 is involved in the production of proinflammatory cytokines. An IL-12 blockade could be useful for the treatment of RA.

Adult↗
PubMed2000

Hepatitis A vaccination in patients with chronic liver disease in Taiwan.

While hepatitis A infection is rarely fatal, mortality is age-dependent, suggesting that cofactors may play a role in disease expression. The safety and immunogenicity of an inactivated hepatitis A vaccine was evaluated in a study involving 60 patients with chronic liver disease (CLD) (56 patients with chronic hepatitis B, and four patients with chronic hepatitis C). A two-dose schedule, at 0 and 6 months, produced 100% seroconversion. All individuals remained seropositive for 12 months, the majority maintaining high levels of antibody during a 5-year follow-up period. The inactivated hepatitis A vaccine was found to be well tolerated and immunogenic in patients with CLD. However, the immune response generated was inferior to that observed in healthy individuals, indicating the need for a higher dose, and the two-dose schedule to ensure adequate protection.

Adolescent↗
PubMed2000

Interferon-gamma-independent CD8+ T cell-mediated protective anti-malaria immunity elicited by recombinant adenovirus.

Recombinant adenovirus, expressing the CS protein of Plasmodium yoelii, AdPyCS, was shown to induce a comparable degree of T cell-mediated protection against malaria as a single dose of irradiated P. yoelii sporozoites, causing inhibition of liver stage development. We now report that differently from sporozoite-induced immunity, interferon (IFN)-gamma does not mediate the protective immunity induced by AdPyCS, since a similar degree of protection was observed in AdPyCS immunized mice lacking IFN-gamma-/- and the IFN-gamma receptor (IFN-gammaR-/-) compared to that in wild-type mice. Depletion of CD8+ T cells from these immunized mice almost completely abolished the AdPyCS-induced immunity, indicating that the immunization with AdPyCS induces CD8+ T cell-mediated protective anti-malaria immunity, which is independent of IFN-gamma.

Adenoviridae↗
PubMed2000

T-DNA insertional mutagenesis for functional genomics in rice.

We have produced 22 090 primary transgenic rice plants that carry a T-DNA insertion, which has resulted in 18 358 fertile lines. Genomic DNA gel-blot and PCR analyses have shown that approximately 65% of the population contains more than one copy of the inserted T-DNA. Hygromycin resistance tests revealed that transgenic plants contain an average of 1.4 loci of T-DNA inserts. Therefore, it can be estimated that approximately 25 700 taggings have been generated. The binary vector used in the insertion contained the promoterless beta-glucuronidase (GUS) reporter gene with an intron and multiple splicing donors and acceptors immediately next to the right border. Therefore, this gene trap vector is able to detect a gene fusion between GUS and an endogenous gene, which is tagged by T-DNA. Histochemical GUS assays were carried out in the leaves and roots from 5353 lines, mature flowers from 7026 lines, and developing seeds from 1948 lines. The data revealed that 1.6-2.1% of tested organs were GUS-positive in the tested organs, and that their GUS expression patterns were organ- or tissue-specific or ubiquitous in all parts of the plant. The large population of T-DNA-tagged lines will be useful for identifying insertional mutants in various genes and for discovering new genes in rice.

Base Sequence↗
PubMed2000

Drug-related pemphigus and angiotensin converting enzyme inhibitors.

A 105-year-old woman developed pemphigus foliaceus. She had been on fosinopril, an angiotensin-converting enzyme inhibitor (ACE inhibitor) for 4 years. Anti-intercellular cement substance antibodies were positive with titre > 160. She died during admission of an unrelated illness. A 57-year-old man developed pemphigus vulgaris after 11 months treatment with quinapril. At 14 months after developing pemphigus, this man continues on prednisone and azathioprine. We speculate that these are cases of ACE-inhibitor-related pemphigus and we review ACE-inhibitor-related pemphigus.

Aged↗
PubMed2000

Isolation and characterization of novel presenilin binding protein.

Approximately 50% of familial Alzheimer's disease (AD) cases are linked to the presenilin (PS) gene. This suggests that an altered function of mutated PSs accounts for a fundamental process leading to AD. Here we identify a new PS binding protein, PBP, which is highly expressed in cerebral cortex and hippocampus. immunohistochemical studies and cell fractionation analysis show that PBP redistributes from cytoplasm to membranes in the presence of PS. In addition, PBP is deficient in the soluble fraction of sporadic AD brains.

Alzheimer Disease↗