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W Woo

Publications and source records attributed to W Woo.

At least 19 recordsLinked to original sources
PubMed2003

Zinc accumulation in N-methyl-N-nitrosourea-induced rat mammary tumors is accompanied by an altered expression of ZnT-1 and metallothionein.

Zinc is essential for cell proliferation. Several human studies have shown that in breast cancer tissues, zinc concentration expressed on a per tissue weight basis is higher than that in normal breast tissues. However, the mechanisms involved are unknown. N-methyl-N-nitrosourea (MNU)-induced rat mammary tumorigenesis is one of the most widely used rodent mammary tumorigenesis models for studying human breast cancer due to their similarities in hormone dependency, pathogenesis, histological classification, and immunocytochemical markers. This study was to establish if there was an accumulation of zinc in MNU-induced rat mammary tumors and, if there was, to explore the possible mechanisms involved. Sprague-Dawley rats were sham-treated or MNU-treated (50 mg/kg; n = 12) for 100 days. In MNU-induced mammary tumors (mammary tumors), zinc concentration expressed on a per dry weight basis was 12 times of that in normal mammary glands. Moreover, the mRNA level of ZnT-1 (a transporter involved in zinc efflux) in mammary tumors was reduced by 55% as compared with that in normal mammary glands. The mRNA level of Nramp2 (a divalent cation importer) and ZnT-4 (another transporter involved in zinc efflux) was unaffected by MNU-induced mammary tumorigenesis. The mRNA and protein levels of metallothionein (a putative zinc storage protein) in mammary tumors were 1.3 and 3.5 times of that in normal mammary glands, respectively. Collectively, our observations showed that zinc is accumulated in MNU-induced rat mammary tumors and this accumulation is accompanied by an altered expression of ZnT-1 and metallothionein, suggesting that zinc homeostasis might be altered in MNU-induced rat mammary tumorigenesis. Because zinc is essential to cell proliferation and cell proliferation is increased in mammary tumors, zinc accumulation is likely a part of an integrated effort to ensure sufficient zinc supply to sustain tumor growth.

Animals↗
PubMed2001

Effect of dietary zinc intake on N-methyl-N-nitrosourea-induced mammary tumorigenesis in rats.

Numerous studies have shown that zinc nutrition influences the growth of several types of tumor. However, the influence of zinc nutrition on mammary tumorigenesis is not known. To study the effects of dietary zinc intake on N-methyl-N-nitrosourea (MNU)-induced mammary tumorigenesis, female Sprague-Dawley rats were fed an egg-white-based diet providing 3 (Z3), 12 (Z12), or 31 (Z31) mg zinc/kg diet ad libitum. In addition, two pair-fed controls, PFZ12 and PFZ31, were also included. Fourteen weeks after MNU injection, cumulative tumor incidence and total number of tumors were lower in Z3 rats than in Z12 and Z31 rats. Cumulative tumor incidence and total number of tumors were lower in Z3 rats than in PFZ12 rats, but were the same as in PFZ31 rats. Cumulative tumor incidence and total number of tumors were also lower in pair-fed controls than in their corresponding ad libitum controls, but were the same between the ad libitum controls. Overall, the results showed that the effect of marginal zinc deficiency on MNU-induced mammary tumorigenesis in rats was primarily the result of a reduced feed intake associated with marginal zinc deficiency rather than zinc per se.

Animals↗
PubMed2000

A novel high-throughput method for accurate, rapid, and economical measurement of multiple type 1 diabetes autoantibodies.

Prediction of Type 1 diabetes for study of preventive therapies requires screening the general population, where 85% of new cases occur. Even with HLA-based prescreening, nearly 20% of all children will need multiple serum autoantibody testings. High-throughput, economical, and accurate methods are therefore essential. We have developed such a radiobinding method, using 96-well microtiter plates and a novel immune complex capture method via membrane-bound Protein A. Each microtiter plate contained a standard negative control serum, and low-, medium-, and high-level positive control sera. All sera were evaluated in triplicate. This readily allowed quality control criteria both for triplicates of individual sera and for each 96-well plate. Inter-assay coefficients of variation (CVs) were all </=16%, while intra-assay CVs were all </=10%. The assay was found to be sensitive (to detect autoantibodies in patients) and specific (low reactivity in thousands of healthy volunteers). The format worked well using diverse antigens such as 35S-met-GAD65, 35S-met-ICA512/IA2, 35S-met-Phogrin, and 125I-insulin, and could be used for simultaneous screening of reactivity to both GAD65 and ICA512/IA2 in the same well. Diagnostic accuracy compared favorably with microcentrifuge tube-based Protein A-agarose GAD65 and IA2 autoantibody radiobinding assays and with acid-charcoal-polyethylene glycol (PEG) based competitive insulin autoantibody assays. In the case of 125I-insulin, comparing signal in the absence versus presence of cold insulin competitor was not necessary. Total serum volumes required were only 6 microl for GAD and ICA512, and only 15 microl for IAA. The method costs less than all other commonly used formats, and should be useful for population screening.

Adolescent↗
PubMed1999

Immunogenetic analysis suggests different pathogenesis for obese and lean African-Americans with diabetic ketoacidosis.

OBJECTIVE: When presenting with diabetic ketoacidosis (DKA), lean and obese patients differ in their subsequent clinical course. Although lean patients tend to remain insulin dependent, most obese patients recover endogenous insulin secretion and discontinue insulin therapy. The aim of this study was to determine whether obese African-American patients with DKA could be determined to have type 1 or type 2 diabetes based on insulin secretion or the presence of immunological and genetic markers. RESEARCH DESIGN AND METHODS: This was a prospective study that analyzed the clinical characteristics, insulin secretion indices, immunological markers (islet cell, GAD, ICA512, and insulin autoantibodies), and HLA susceptibility genes (DR/DQ) in 131 patients with DKA (77 obese and 54 lean), 51 obese patients with hyperglycemia but no DKA, and 25 nondiabetic subjects. All subjects were African-American. Beta-cell function was evaluated by the C-peptide response to glucagon (1 mg i.v.) within 48 h of resolution of DKA or hyperglycemia. RESULTS: The acute C-peptide response was lower in obese DKA patients (1.0+/-0.1 ng/ml) than in obese patients with hyperglycemia (1.7+/-0.2 ng/ml, P < 0.01), but was higher than that in lean DKA patients (0.2+/-0.1 ng/ml, both P < 0.01). The overall prevalence of autoantibodies in obese subjects with DKA (17%) and obese subjects with hyperglycemia (16%) was lower than that in lean subjects with DKA (65%, P < 0.01). Obese patients with hyperglycemia and positive autoantibodies had lower rates of insulin secretion than those without antibodies. Regardless of body weight, all DKA patients with GAD autoantibodies carried the DQB1*0201 allele. However, there were no significant differences in HLA distribution between the three patient groups. CONCLUSIONS: Our results indicate that most obese African-American patients with DKA have type 2 diabetes characterized by higher insulin secretion, the absence of autoimmune markers, and a lack of HLA genetic association. In contrast, most lean African-American patients with DKA have metabolic and immunological features of type 1 diabetes. At presentation, assessment of beta-cell function and determination of autoimmune markers allow for correct classification of diabetes in African-Americans with hyperglycemic crises.

Adult↗
PubMed1998

Treating patients with documented atherosclerosis to National Cholesterol Education Program-recommended low-density-lipoprotein cholesterol goals with atorvastatin, fluvastatin, lovastatin and simvastatin.

OBJECTIVES: This study compared the efficacy and safety of atorvastatin, fluvastatin, lovastatin, and simvastatin in patients with documented atherosclerosis treated to U.S. National Cholesterol Education Program (NCEP) recommended low-density-lipoprotein (LDL) cholesterol concentration (< or = 100 mg/dl [2.59 mmol/liter]). BACKGROUND: For patients with advanced atherosclerosis, NCEP recommends lipid-lowering drug therapy if LDL cholesterol remains > or = 130 mg/dl (3.36 mmol/liter). METHODS: A total of 318 men or women with documented atherosclerosis and LDL cholesterol > or = 130 mg/dl (3.36 mmol/liter) and < or = 250 mg/dl (6.5 mmol/liter), and triglycerides < or = 400 mg/dl (4.5 mmol/liter) participated in this 54-week, multicenter, open-label, randomized, parallel-group, active-controlled, treat-to-target study. Patients were titrated at 12-week intervals until the LDL cholesterol goal was reached. Number of patients reaching target LDL cholesterol levels and dose to reach target were evaluated. RESULTS: At the starting doses, atorvastatin 10 mg produced significantly greater decreases (p < 0.05) in plasma LDL cholesterol than the other treatments. Subsequently, the percentage of patients reaching goal at the starting dose was 32% for atorvastatin, 1% for fluvastatin, 10% for lovastatin and 22% for simvastatin. Atorvastatin-treated patients required a lower median dose than other treatments. Median doses at week 54 with the last available visit carried forward were atorvastatin 20 mg/day, fluvastatin 40 mg/day + colestipol 20 g/day, lovastatin 80 mg/day, simvastatin 40 mg/day. CONCLUSIONS: A significantly greater number (p < 0.05) of patients with confirmed atherosclerosis treated with atorvastatin reached the target LDL cholesterol concentration at the starting dose than patients treated with fluvastatin or lovastatin, and significantly fewer (p < 0.05) patients treated with atorvastatin required combination therapy with colestipol to achieve target LDL cholesterol concentrations than all other statins tested.

Anticholesteremic Agents↗
PubMed1998

Association between autoantibody markers and subtypes of DR4 and DR4-DQ in Swedish children with insulin-dependent diabetes reveals closer association of tyrosine pyrophosphatase autoimmunity with DR4 than DQ8.

HLA DQA1*0301-DQB1*0302 (DQ8) and DQA1*0501-DQB1*0201 (DQ2) are positively and DQA1*0102-DQB1*0602 (DQ6) negatively associated with IDDM. In DQA1*0301-DQB1*0302 (DQ8)-positive patients, susceptibility is also mediated by DRB1*0401. The aim of the study was to determine the association between HLA-DR4 and DQ and the presence of GAD65, ICA512, and insulin autoantibodies as well as ICA in 425 Swedish children with IDDM and 367 controls in the age group of 0-15 years. We found that ICA512 autoantibodies were associated primarily with DRB1*0401 and not with DQA1*0301-DQB1*0302 (DQ8). No such hierarchy could be demonstrated for insulin autoantibodies, which were associated with both DQA1*0301-DQB1*0302 (DQ8) and DRB1*0401. GAD65 autoantibodies, known to be closely associated with DQA1*0501-DQB1*0201 (DQ2)-DRB1*0301 haplotype, also showed no preferential association with DQA1*0301-DQB1*0302 (DQ8) versus DRB1*04. These results suggest that the immune response to different beta-cell autoantigens may be mediated via HLA class II molecules from different loci. Design of the antigen-specific immuno-intervention trials should take into account these HLA-DR and DQ subtype associations.

Adolescent↗
PubMed1988

Antibody activity to herpes simplex virus in mouse Ig classes and IgG subclasses.

Recent studies indicate that Ig class and IgG subclass induction varies for different proteins and further that some Ig subclasses, like IgG2a, are more efficient in important biologic processes such as antibody-dependant cell-mediated cytotoxicity (ADCC). Many proteins of herpes simplex virus type 1 (HSV-1) are immunogenic and induce immunoglobulin responses. To determine the distribution of immunoglobulins induced by HSV-1 proteins, we studied immune mouse serum using an Ig isotype specific Elisa assay for antiviral activity. We found by endpoint analysis that the antiviral titer was 1:12,903 for IgG1, 1:5141 for IgG2a, 1:2140 for IgG2b and 1:229 for IgG3. To identify which isotypes were induced by individual glycoproteins and other viral proteins, Western blots containing HSV-1 proteins were probed with immune serum and isotype specific second antibodies. gB, gC, gD and the 42/44KDa nucleocapsid complex induced strong IgG1, IgG2a, IgG2b responses. IgG3 reactivity with viral proteins appeared weaker. Among the IgG3 reactivities detected on immunoblots, gB and gC were the most intense. Other proteins which elicited IgG1, IgG2a and IgG2b responses were 170KDa, 154KDa and gE. IgA responses were induced by 154KDa, gC, gB, gE and gD. Prominent IgM responses included gB, gC, gD and the 42KDa protein. These results indicate that HSV-1 glycoproteins induce prominent responses in all IgG isotypes except IgG3. The biologic implications of the data are discussed.

Animals↗
PubMed1988

Murine IgG subclass responses to herpes simplex virus type 1 and polypeptides.

The antibody response to herpes simplex virus (HSV) is complex and involves antibody to at least 33 virus-induced polypeptides. Serum IgG contains four isotypes in mice and it is known that the isotypes differ in their biological functions and that individual antigenic proteins may preferentially elicit restricted isotype responses. We therefore examined the anti-polypeptide isotypes induced in immune mouse serum. By ELISA, we found that the total serum virus-specific antibody activity was 51% IgG1, 39% IgG2a, 11% IgG2b and 1% IgG3 in immune ICR strain mice and 51%, 45%, 4% and 0.4% respectively in strain BALB/c mouse immune serum. These proportions are significantly different from those reported for other virus infections. Sepharose-Protein A affinity-purified isotypes were also studied and showed IgG1 greater than IgG2a greater than or equal to IgG2b much greater than IgG3 activity per microgram of isotype, indicating that competition between isotypes present in high concentrations did not significantly alter the results. Immunoblotting studies of the purified isotypes showed that the major immunogenic HSV-1 proteins (VP155, gC, gB, pgB, gD and nucleocapsid proteins 42K and 44K) induced all isotypes. However, the isotype responses were not uniform among the glycoproteins and some other proteins. In addition neutralization assays of the purified isotypes indicated that IgG2a and IgG2b had significantly greater neutralizing capacity than IgG1, suggesting that less of the IgG1 was directed against neutralizing virion epitopes. These data are discussed with respect to the biological implications in host defence.

Animals↗
PubMed1988

The polyspecific immunoglobulin response to HSV-1 viral proteins: determination of immunogenic proteins and relative antibody titres to individual polypeptides by immunoblotting.

We developed an immunoblotting procedure to characterise the polyspecific immunoglobulin response to the proteins of herpes simplex virus (HSV)-1. We found that 8-20% gradient polyacrylamide gels provided no advantage over fixed 8.5% gels for preparing Western blots for use in immunoblotting. The amount of protein loaded on the gels markedly influenced which proteins were detected by immune serum. The presence of Triton-X-100 0.5% in washes and buffers improved band clarity on immunoblots. In optimal conditions, immune mouse serum reacted with up to 33 HSV-1 lysate proteins. Six bands or regions appeared to be of major immunogenic reactivity, including the (122-130) x 10(3)-mol. wt region, a 75 x 10(3)-mol. wt protein, the gD region of approximately (56-64) x 10(3)-mol. wt and two non-glycosylated bands at mol. wts(10(3)) 42 and 44. Minor proteins, more weakly reactive, were detected at 27 other areas. The relative antibody titres in immune mouse serum to the different major regions showed antibody titre to gD greater than gB/gC greater than (42/44) x 10(3) much greater than P75 much greater than VP154. Most human sera reacted with all of the major and many of the minor immunogenic proteins but individual sera varied markedly in the proteins recognised. We conclude that immunoblotting is valuable for evaluating immunoglobulin responses to major and minor immunogenic proteins of HSV-1.

Animals↗
PubMed1988

The immunoglobulin response to individual HSV-1 viral polypeptides: kinetics of the response during primary and secondary experimental infection with herpes simplex virus.

We studied the immunoglobulin response to individual viral polypeptides in experimental primary and secondary infection with herpes simplex virus (HSV)-1 in mice. After a single footpad inoculation with 10(5.6) pfu of HSV-1, immunoglobulin to proteins mol. wts (10(3)) 44 and 75 appeared on day 7. Antibodies to gB, gC, gD, 42 x 10(3)- and (48-52) x 10(3)-mol. wt proteins appeared on day 11 and antibody to the major capsid protein, VP154, appeared on day 15 after infection. The secondary immune response was characterised by early production of antibody to gD on day 3 followed by antibodies against the 42 x 10(3)- and 44 x 10(3)-mol. wt proteins on days 4 and 5 respectively. Antibodies to glycoprotein gC and gB were delayed until day 7 of the secondary immune response. In both primary and secondary immune responses the responses against proteins of mol. wts (10(3)) 42 and 44 were particularly intense and of high titre. We conclude that the kinetics of anti-polypeptide antibody appearance is markedly asynchronous; and that the anti-glycoprotein responses occur too late in primary infection to contribute to viral clearance.

Animals↗
PubMed1987

Possible neural basis for age-dependent resistance to neurologic disease from herpes simplex virus.

Twenty-week-old mice are known to be resistant to HSV induced neurologic disease, while 5-week-old mice are susceptible. Although age-dependent resistance to disease has been attributed to immunologic maturation, most immunologic development is complete by about 3 weeks of age. We, therefore, postulated that differences in neural spread were involved and we compared the pathogenesis of viral spread in 5-week- and 20-week-old mice. Following footpad infection with 10(5.3) PFU HSV-1, virus was detected in homogenates of sciatic nerve and spinal cord 3-4 days sooner in 5-week-old versus 20-week-old mice. Virus titers in footpad homogenates were 10(5.2) to 10(6.0) in both groups, thus differences in virus replication or immunologic restriction at the initial site of infection could not account for the difference in neural spread. The rate of virus spread to the dorsal root ganglia (DRG) was assessed by ganglia explant/co-cultivation to detect virus presence at various times after footpad infection and by measuring sciatic nerve length. In 5- and 20-week-old mice the rate of virus spread to DRG was 28 mm/day and 4-12 mm/day respectively. We conclude that neural uptake and/or transport of virus may contribute to the difference in susceptibility to neurologic disease.

Aging↗
PubMed1984

Microtiter radioimmunoprecipitation assay of HSV-1 polypeptides with recovery and SDS-PAGE analysis of precipitated proteins: usefulness as screening test for large numbers of specimens including hybridoma supernates.

Immunoprecipitation of radiolabeled polypeptides from complex mixtures of proteins was performed in polystyrene microtiter plates using staphylococcus protein A and various antibody preparations. The method is (1) rapid, (2) uses multichannel micropipettor technology, (3) handles large numbers of specimens easily, (4) requires very small volumes of antigen and antibody (5-50 microliters), (5) provides replicates for statistical analysis and (6) allows recovery of precipitated proteins for direct SDS-PAGE analysis of precipitated proteins. We have shown it is useful as a test to screen large numbers of sera or to characterize monoclonal antibody-containing samples.

Animals↗