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S K Lo

Publications and source records attributed to S K Lo.

At least 73 records · Page 4Linked to original sources
PubMed1997

Immunohistochemical metallothionein expression in thymoma: correlation with histological types and cellular origin.

Metallothioneins (MTs) are low molecular weight and cysteine-rich intracellular proteins involved in metal homeostasis and detoxication. They are found in certain normal tissues, and are overexpressed in various tumours with correlation to more aggressive behaviour in certain tumours. Since the histopathological types of thymoma have unpredictable invasive potential, MT over-expression was investigated as a possible marker of the invasive potential of thymomas. We studied immunohistochemical MT expression in 27 non-invasive thymomas, 20 micro-invasive thymomas, and 23 macro-invasive thymomas with a mouse monoclonal anti-MT antibody E9 on formalin-fixed paraffin-embedded tissues. MT expression was significantly different among the three groups of thymomas (P = 0.02) with a stronger expression in invasive thymomas (P = 0.003). However, MT expression was not exclusively limited to invasive thymomas. Therefore, it could not be used as a marker of aggressive potential in individual thymomas. Analysis of MT expression according to the histological types of the thymomas revealed that eight of nine spindle cell thymomas, none of 10 small polygonal cell thymomas, four of 14 mixed thymomas, seven of 29 large polygonal cell thymomas, and seven of eight squamoid thymomas significantly expressed MT. There was a statistically significant difference in MT expression among different histological types of thymomas (P = 0.000). The strongest and most consistent expression was observed in spindle cell thymoma and squamoid thymoma. Since spindle cell thymoma was usually non-invasive and squamoid thymoma was more aggressive, MT expression does not correlate with the invasive potential of different histological types of thymomas. But because medullary epithelial cells of the thymus were positive for MT, our results suggest that both spindle cell thymoma and squamoid thymoma might derive from the medullary compartment of the thymus.

Animals↗
PubMed1997

Distinct genotypic distributions of cytomegalovirus (CMV) envelope glycoprotein in bone marrow and renal transplant recipients with CMV disease.

A prospective study of the spectrum of glycoprotein B (gB) and glycoprotein H (gH) genotypes of cytomegalovirus (CMV) was conducted with five categories of patients: viremic bone marrow-transplant (BMT) recipients who developed CMV disease after BMT (n = 22), viremic BMT recipients without CMV disease (n = 11), viremic renal-transplant recipients who developed CMV disease after transplantation (n = 14), viremic renal-transplant recipients without CMV disease (n = 13), and premature babies with asymptomatic congenital CMV infections (n = 13). Genotypic stability was observed because the gB and gH genotypes of multiple isolates obtained from a single patient were identical. The distribution of gH genotypes in patients of all groups studied were similar. However, there was a unique distribution of the gB genotype in the first category of patients, i.e., BMT recipients with CMV disease, which was distinct from those of all other categories (P < 0.05). CMV isolates from 54% of BMT recipients with CMV disease exhibited gB type 2, while isolates from 46, 50, 69, and 77% of the BMT recipients without CMV disease, renal-transplant recipients with and those without CMV disease, and premature babies with congenital CMV infection, respectively, were of gB type 1. An analysis of the clinical characteristics of BMT recipients with CMV disease indicated that all underwent either an allogeneic or matched, unrelated donor transplant, and half had severe acute graft-versus-host disease (grades 2 to 4). The statistically significant genotypic difference between CMV isolates from BMT recipients with and without CMV disease was not observed between isolates from renal-transplant recipients with and without CMV disease. We speculate that differences in pathogenesis in different patient groups might account for these observations. These findings would also facilitate decision making about the choice of recombinant CMV glycoprotein vaccine required to immunize transplant donors and the subsequent adoptive transfer of immunity to BMT recipients. When the source of CMV DNA required for genotyping was investigated among renal-transplant recipients, direct use of peripheral blood leukocytes was 95% effective compared to the effectiveness of cells obtained from conventional culture of peripheral blood specimens.

Adult↗
PubMed1997

Detection of CMV DNA in bone marrow transplant recipients: plasma versus leucocyte polymerase chain reaction.

AIMS: To compare the nested polymerase chain reaction (PCR) assay for the detection of cytomegalovirus (CMV) DNA in peripheral blood leucocytes and plasma obtained from heparinised blood; to determine the efficiency of various DNA extraction methods to minimise inhibition of plasma PCR and their effect on the sensitivity of plasma PCR; to determine the inhibitory effect of heparin, dextran, and EDTA on the CMV PCR assay. METHODS: 217 heparinised blood specimens from 58 bone marrow transplant patients were processed and the sensitivities and specificities of the PCR assays using peripheral blood leucocytes and plasma (with simple, Instagene, and Geneclean extraction methods) were compared to those of conventional CMV culture. In a separate experiment, dilutions of heparin, dextran, and EDTA were included in PCR assays. RESULTS: The detection of CMV DNA using peripheral blood leucocytes for PCR assay was significantly more sensitive (100%) than when using plasma (60%). Instagene and Geneclean extraction removed inherent inhibition but did not improve the sensitivity of the plasma PCR reaction. Heparin had an inhibitory effect on PCR. CONCLUSIONS: PCR assay using peripheral blood leucocytes is better than plasma for guiding the prescription of ganciclovir to bone marrow transplant patients. Heparin is inhibitory to the plasma PCR reaction.

Bone Marrow Transplantation↗
PubMed1997

Hemostatic and fibrinolytic response to desmopressin in uremic patients.

Desmopressin (DDAVP) 0.3 micrograms/kg was infused in 20 uremic patients with prolong bleeding time. Prior to infusion, the uremic patients had a reduced level of tissue plasminogen activator (t-PA), normal levels of von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (vWF:RCo) and elevated level of factor VIII coagulant activity (FVIII:C). Patients with lower hematocrit or t-PA levels tended to have a longer bleeding time. One hour after DDAVP infusion, the bleeding time was shortened significantly. This improvement was significant in all patient groups irrespective of the high or low initial levels of factor VIII complex components. Plasma levels of FVIII:C, vWF:Ag, vWF:RCo and t-PA all increased significantly. The magnitude of increase in these factors, however, was not significantly correlated with the extent of bleeding time shortening. The multiple regression model for predicting the extent of bleeding time shortening suggested only two variables, viz initial bleeding time and posttreatment FVIII:C activity to be of significance. The present results indicate that the hemostatic response to DDAVP is uniform in uremic patients, regardless of whether the initial activities of factor VIII complex components are high or low. Posttreatment FVIII:C activity appears to play a significant role in the hemostatic action of DDAVP. Furthermore, a depressed fibrinolytic activity was generally observed to concur with the hemostatic defect in uremic patients.

Adolescent↗
PubMed1997

Endoscopic management of pancreatic pseudocysts.

Pancreatic pseudocyst is a major complication of acute and chronic pancreatitis. Surgical drainage, the mainstay of therapy for this condition, is associated with 5% mortality, 25% morbidity, and 10% recurrence rates. Efforts to improve these figures and reduce the typically long hospitalizations have brought about percutaneous and endoscopic drainages. This article describes the endoscopic techniques and attempts to summarize their results based on a literature review. Before endoscopic drainage is carried out, other cystic lesions must be excluded with clinical history, computed tomography findings, and perhaps cyst fluid CEA content and cytology. Endoscopic techniques include wide transmural incision, transmural puncture and stenting, and transpapillary stenting. Either transgastric or transduodenal drainages can be carried out depending on the proximity of the pseudocyst to the gastrointestinal lumen. Endosonography has become an integral part of the transmural procedure because it can help diagnose cystic neoplasms, localize pseudocysts, detect submucosal vessels, and measure the cyst to mucosal distance for transmural punctures. Temporary nasocystic drains are often used to complement stenting during the initial treatment phase. Overall, the endoscopic experience in expert hands is associated with 94% initial technical success, 90% cyst resolution, and 16% recurrence rates. Additional nonendoscopic interventions, mostly surgical, are necessary in 17% of patients. Complication rate is 20%, with < 1% mortality. These data suggest that endoscopic drainage should become an accepted modality in the treatment of pseudocysts. Because of significant technical difficulty and potential risks, endoscopic drainages should only be carried out by experienced endoscopists and at well-equipped facilities.

Adult↗
PubMed1997

Cutaneous microcirculation of diabetic foot: combined isolated cold stress testing and laser Doppler flowmetry study.

We evaluated the peripheral microvascular response to an isolated cold stress test in patients with diabetes of various severities. We studied four groups: diabetics without neuropathy (group A: six patients), diabetics with peripheral motosensory neuropathy (group B: 12 patients), diabetics with peripheral vascular disease (group C: eight patients), and healthy controls (group D: 16 patients). Digital temperatures of all four groups decreased during the 20-minute cooling period, though more in the controls, then increased during the 20-minute rewarming period with no difference among the groups. The digital temperatures of diabetics with and without neuropathy were higher than those of diabetics with peripheral vascular disease and controls throughout. Higher mean digital skin temperature was also noted in groups A and B throughout. Significant decreases in laser Doppler flowmetry value from the last minute of acclimatization to the last minute of the cooling session were found in groups A, B, and D. A significant increase during rewarming was found only in group A (p = 0.0475). Our study showed that increased digital vascular flow was consistent with arteriovenous shunting and abnormal vascular control in diabetics with and without neuropathy. Diabetic patients with peripheral vascular disease had the lowest value and the least fluctuation in laser Doppler flowmetry, but their digital skin temperature did not differ significantly from that of the normal subjects.

Adult↗
PubMed1997

Cycling injuries among junior high school children in Taiwan.

We surveyed the injuries sustained by 197 junior high school students (aged 12 to 15 years) while riding a bicycle within the previous 12 months, together with the same number of controls matched according to age and sex. The case sites and control sites, selected from routes control subjects would have taken if pursuing the same purpose as the case subject at the time of the accident, were also investigated. Male students and older students were found to be at higher risk. One-third of the injuries occurred while the students were traveling to school. Nearly 40% of the accidents happened between 15:00 and 19:00, and 52% occurred during the summer months. More than half of the accidents took place near street corners. Injuries were mainly (89%) to one of the limbs. Injuries were more severe among those with head injuries. None of the injured children wore a helmet while cycling. Most injuries (83%) were due to collisions with another vehicle. Motorcycles were involved in the collisions most often. When compared with the total number of registered vehicles, the proportion of trucks, light commercial vans, and taxis involved in the crashes was significantly higher. Drivers of the vehicles involved were primarily males, evenly distributed across all age groups. The volume of traffic was marginally heavier at case sites, but estimated average speeds of vehicles were similar between case and control sites. More obstacles, such as illegally parked vehicles and vendors' stalls, were found at case sites. In addition to wearing a helmet, other prevention strategies should be considered.

Accidents, Traffic↗
PubMed1996

Structure-function analysis of Leishmania lipophosphoglycan. Distinct domains that mediate binding and inhibition of endothelial cell function.

We have shown that Leishmania lipophosphoglycan (LPG) inhibits IL-1 beta gene expression in human monocytes. Here, we show that LPG can bind in a time-dependent manner and suppress endothelial cell activation, possibly via specific LPG domains. Endotoxin (10 ng/ml, 4 h) consistently caused endothelium to increase monocyte adhesion (approximately 20-fold). LPG pretreatment (2 microM, 2 h) completely blocked endotoxin-mediated monocyte adhesion. LPG did not grossly suppress endothelial functions because TNF-alpha- and IL-1 beta-mediated adhesion toward monocytes were not affected. Using four highly purified LPG fragments (namely, repeating phosphodisaccharide (PGM), phosphoglycan, phosphosaccharide core-lyso-alkyl-phosphatidylinositol (core-PI), and lyso-alkyl-phosphatidylinositol (lyso-PI)), we examined whether these fragments can independently inhibit endothelial adhesion. In contrast to that of intact LPG, neither the four LPG fragments (2 microM, 2 h) independently nor the co-addition of phosphoglycan and core-P1 fragments blocked the endotoxin-mediated adhesion to monocytes. To determine whether the fragments can reverse the effect of intact LPG, endothelial cells were first pretreated with the LPG fragments (10 microM, 15 min), followed by the addition of LPG (2 microM). All four LPG fragments fully reversed the effect of LPG. Simultaneous addition of LPG fragments and intact LPG caused only partial suppression (approximately 45%), while the addition of LPG fragments 14 min later had no reversal effect. Flow cytometry revealed that only core-P1 and lyso-P1 competitively inhibited (approximately 30%) LPG binding. Conversely, LPG competed with the binding of [3H]lyso-P1 (approximately 30%). Furthermore, mAb against the PGM reversed (approximately 70%) the effect of LPG. Thus, the lyso-P1 domain on LPG mediates binding to endothelial cells, whereas the PGM domain mediates the cell inhibitory effect.

Animals↗
PubMed1996

Inter-observer variability of portal hemodynamics measured by Doppler ultrasound on three different locations of portal vein.

Doppler ultrasound is a noninvasive modality for portal hemodynamic study. However, inter-observer variability has been observed. This study has investigated ways to produce less inter-observer variability. Doppler ultrasound portal vein hemodynamic studies were carried out by three well-trained specialists on 20 healthy hospital staff members. The intra-hepatic, first branch, right portal vein, the hilar portal vein, and the extra-hepatic portal vein were chosen for study. With respect to the diameter of portal veins, a significant inter-observer variability was found for the first branch right portal vein and the extra-hepatic portal vein, but not for the hilar portal vein. For maximal portal vein velocity studies, inter-observer variability was not found at any location. A significant failure rate was noted for the measurement of extra-hepatic portal vein velocity. Only 8 volunteers had complete data from all of the three investigators. A significant variability was also noted for the average velocity of extra-hepatic portal vein. We conclude that Doppler ultrasound hemodynamic studies of the hilar portal vein has the most acceptable inter-observer variability and thus should be used for longitudinal portal hemodynamic studies.

Adult↗
PubMed1996

Superinfection with hepatitis C virus in hemodialysis patients with hepatitis B surface antigenemia: its prevalence and clinical significance in Taiwan.

A survey of hepatitis B surface antigen (HBSAG) and antibodies against hepatitis C virus (anti-HCV) in 173 patients undergoing hemodialysis in Taiwan revealed that 15 (9%) patients were positive for both HBSAG and anti-HCV, 106 (61%) were positive for anti-HCV alone, and 14 (8%) were positive for HBSAG alone. Most HBSAg positivity was acquired before the onset of hemodialysis. Anti-HCV positivity, however, was mainly acquired via the hemodialysis procedure. Patients with dual markers were younger (43.7 +/- 3.3 years old, p = 0.0274), had the longest period on hemodialysis (6.6 +/- 1.3 years, p < 0.001), and more severe liver dysfunction. When compared with those who were negative for both markers, patients with both HBSAG and anti-HCV had an increased incidence of chronicity (5/15 vs. 2/38; p < 0.05), ultrasonographic cirrhosis (5/15 vs. 1/38; p < 0.05), and clinical decompensation (2/15 vs. 0/38; p < 0.05). Their risk for developing ultrasonographic cirrhosis and clinical decompensation was also greater than that of patients with anti-HCV alone (5/15 vs. 8/106 and 2/15 vs. 2/106; p < 0.05 for both). The presence of HBSAG alone, however, did not increase the incidence of liver dysfunction. The presence of anti-HCV alone was only associated with a greater elevation of serum alanine aminotransferase (44.2 +/- 5.5 vs. 19.1 +/- 2.5 U/l; p < 0.05) and an increased incidence of chronicity (30/106 vs. 2/38; p < 0.05). Our results indicate that a high prevalence of HCV superinfection impose a significant risk on a large population of HBSAG-positive hemodialysis patients in Taiwan. As the coexistence of anti-HCV and HBSAG is associated with more severe liver dysfunction, it is urgent to devise effective methods to prevent HCV circulation in a hemodialysis environment-especially in a hepatitis B virus endemic area such as Taiwan.

Adolescent↗
PubMed1996

Antiphospholipid antibodies activate vascular endothelial cells.

Antiphospholipid antibodies (aPL) are associated with a syndrome of arterial and venous thrombosis and recurrent fetal loss. We have shown that IgG purified from patients with aPL activate vascular endothelial cells (EC), converting the steady-state, non-thrombotic endothelial surface to a pro-thrombotic state. The aPL-activated EC are characterized by the expression of leukocyte adhesion molecules, including ICAM-1, VCAM, and E-selectin. EC activation is dependent upon the presence of beta 2-GP-I, a cofactor necessary for anticardiolipin reactivity. In addition, EC activation is not attributable to endotoxin contamination, Fc receptor interactions, or immune complexes, but rather is the result of the specific anticardiolipin reactivity of the IgG. Endothelial activation by aPL may be an important mechanism by which these antibodies cause a hypercoagulable state.

Antibodies, Antiphospholipid↗
PubMed1996

Apolipoprotein B 3' hypervariable repeat genotype: association with plasma lipid concentration, coronary artery disease, and other restriction fragment polymorphisms.

Apolipoprotein B gene 3' variable number tandem repeat (VNTR) and related regions were amplified by PCR and analyzed by agarose gel electrophoresis. Eighteen VNTR alleles (VNTR25, 26, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 58, 60) and 45 genotypes were observed in 477 Taiwanese subjects. The VNTR35 allele and genotype VNTR35/35 were observed most frequently in this population. The polymorphism information content was 0.62. Some minor alleles, such as VNTR25 and 60, were found only in coronary artery disease (CAD) and stroke patients in our sampling, and no statistically significant difference was observed in VNTR allelic frequency between control and CAD or stroke patients. Significant differences in allelic distribution of some VNTR alleles were observed between our normal Taiwanese population and a Caucasian group studied by others. VNTR43-47 and AluI+ (coding Ala591) restriction fragment length polymorphism (RFLP) as well as VNTR49-60 and EcoRI- (coding Lys4154) RFLP were found to be highly coinherited. No apparent association between the VNTR genotype and plasma lipid concentration was observed; however, for the same genotype, the CAD and stroke patients frequently showed higher lipoprotein(a) and lower HDL cholesterol concentrations than the control group.

Alleles↗
PubMed1996

Neuritogenesis, not receptor expression, of NG108-15 cells can be modulated by monosialoganglioside GM1.

In this study, involvement of gangliosides in neurite outgrowth and receptor expression of the neuroblastoma X glioma hybrid NG108-15 cloned cells was investigated. Monosialoganglioside GM1 (100 microM) and disialoganglioside GD1a (100 microM) were applied to the culture medium at different concentrations of fetal bovine serum, 1-10%, with or without addition of dibutyryl adenosine 3',5'-cyclic monophosphate (500 microM). In some experiments, 5 mg/ml of cholera toxin B was added to the media to block endogenous GM1. The results indicated that GM1 had an influence on cell proliferation and neuritogenesis but did not induce muscarinic receptor expression of NG108-15 cells.

Animals↗
PubMed1995

Neutrophil inhibitory factor prevents neutrophil-dependent lung injury.

Neutrophil inhibitory factor (NIF) is a recently cloned 41-kDa protein from the canine hookworm that binds CD11b/CD18 and inhibits CD11b/CD18-dependent neutrophil adhesion. We evaluated NIF's effects on neutrophil-dependent lung injury in guinea pigs. Pulmonary vascular endothelial CD54 (ICAM-1) was induced in buffer-perfused lungs by 90-min exposure to 1000 U/ml TNF-alpha. Human neutrophils (2 x 10(7)) were added to the perfusate and activated by 5 x 10(-9) PMA; in some lungs, the neutrophils were pretreated with NIF (100 nM) before their addition to the perfusate. Lung injury was assessed by wet:dry weight ratio, and neutrophil uptake by lung myeloperoxidase (MPO) activity. HUVEC exposed to TNF-alpha for 90 min were assayed for neutrophil adhesion, and we compared PMA-stimulated neutrophil adhesion to endothelial cells and fibrinogen-coated plates. PMA-induced pulmonary edema (lung wet:dry ratio increased from 8.8 +/- 0.7 to 18.8 +/- 4.4) was inhibited by NIF (10.0 +/- 1.0). Lung MPO activity concomitantly decreased from 17.1 +/- 6.1 to 8.7 +/- 1.8 U/mg dry lung tissue in the NIF-treated group, similar to controls (6.9 +/- 2.0). Endothelial monolayer experiments confirmed that NIF reduced neutrophil adherence (basal adhesion of 11 +/- 3% increased to 30 +/- 5% with TNF-alpha pretreatment of endothelial cells, an increase that was reduced to 10 +/- 4% with NIF). Moreover, NIF prevented PMA-induced neutrophil adhesion to fibrinogen, a CD11b/CD18-dependent event, but produced a smaller decrease in adherence to endothelial cells, which also involves CD11a/CD18 integrins. These studies indicate that NIF prevents neutrophil-dependent lung vascular injury by inhibiting neutrophil adhesion to the TNF-alpha-activated endothelium.

Animals↗
PubMed1995

Induction of tissue factor on monocytes by adhesion to endothelial cells.

Activated monocytes express tissue factor (TF), a protein that is important in the pathogenesis of thrombotic disorders. We sought to characterize an adhesion-dependent pathway for monocyte activation. In this study, we showed that adhesion of monocytes to cytokine-activated endothelial cells (EC) increased (approximately 5- to 10-fold) monocyte procoagulant activity (PCA). The PCA was attributed to TF because it was dependent on the coagulation factors VII and X, but not VIII, and was completely blocked by an anti-TF mAb. Direct cell-cell contact between monocytes and EC was required. The induction of TF was rapid, peaked at 30 min, and persisted for 4 h. Northern analysis revealed a rapid (approximately 30 min) increase in TF mRNA following adhesion, distinct from that induced by LPS (approximately 2-4 h). Four-hour TNF-treated EC supported TF expression, but 0.5- and 24-h TNF-treated EC had no effect. An anti-E-selectin mAb (H18/7) exerted partial inhibition, whereas anti-VCAM-1, ICAM-1, and CD11/CD18 mAbs had no inhibition. Synthetic Lewis X (Le(x)) oligosaccharide partially blocked TF induction, whereas sialyl-Le(x) (sLex) oligosaccharide had no effect. Cross-linking Le(x) on monocytes, but not sLex, significantly increased (approximately 10-fold) the TF expression. Le(x) cross-linking induced TF in 30 min and lasted for 4 h. All seventeen anti-Le(x) mAbs induced significant amount of TF generation, and epitope mapping revealed a single binding epitope on Le(x). These findings indicate that adhesion of monocytes to activated EC induces TF generation, and also suggest that Le(x) may represent an important signaling molecule on monocytes.

Blood Coagulation↗