Abstract P3-01-02: Quantitative Analysis and Diagnostic Significance of Methylated SLC19A3 DNA in the Plasma of Breast Cancer Patients

Background: Previously, we have examined the methylation status of SLC19A3 (solute carrier family 19, member 3) promoter and found that SLC19A3 was epigenetically down-regulated in gastric cancer. Here, we aim to develop a new biomarker for cancer diagnosis using methylated SLC19A3 DNA in plasma.

Methods: SLC19A3 gene expression was examined by RT-qPCR. Methylation status of SLC19A3 promoter was evaluated by methylation-specific qPCR. A robust and simple methylation-sensitive restriction enzyme digestion and real-time quantitative PCR assay was developed to quantify SLC19A3 DNA methylation in plasma. Results: Expression of SLC19A3 was significantly down-regulated in 80% (12/15) of breast tumors (P < 0.005). Breast tumors had significant increase in methylation percentage when compared to adjacent non-tumor tissues (P < 0.05). A total of 155 independent plasma samples from participants including 60 breast cancer, 45 gastric cancer patients and 60 healthy subjects were analyzed. Plasma methylated SLC19A3 DNA yielded a ROC curve area of 77%, sensitivity of 82% and specificity of 60% in discriminating breast cancer from control subjects. This marker yielded a ROC curve area of 87%, sensitivity of 90.0% and specificity of 62% in discriminating gastric cancer from control subjects. Elevated level in plasma has been detected not only in advanced stages but also early stages of tumors. Intriguingly, of all DCIS cases from breast cancer patients this plasma marker generated a ROC value of 92%, sensitivity of 100% and specificity of 78% in discriminating DCIS cases from controls. Conclusions: These results suggested that aberrant SLC19A3 promoter hypermethylation in plasma may be a novel biomarker for early breast cancer diagnosis.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-01-02.

Digitally tunable, wide-band amplitude, phase, and frequency detection for atomic-resolution scanning force microscopy

Frequency-modulation atomic force microscopy (FM-AFM) relies on an accurate tracking of the resonance frequency of a scanning probe. It is now used in environments ranging from ultrahigh vacuum to aqueous solutions, for slow and for fast imaging, with probes resonating from a few kilohertz up to several megahertz. Here we present a versatile experimental setup that detects amplitude, phase, and frequency of AFM probes for resonance frequencies up to 15 MHz and with >70 kHz maximum bandwidth for amplitude/phase detection. We provide generic parameter settings for variable-bandwidth frequency detection and test these using our setup. The signal-to-noise ratio of the frequency detector is sufficiently high to record atomic-resolution images of mica by FM-AFM in aqueous solution.

Role of miR-143 Regulating DNA Methyltransferases 3A in Breast Cancer

Background and Aims: MicroRNAs (miRNAs) are 19-25-nucleotides regulatory non-protein-coding RNA molecules that regulate the expressions of a wide variety of genes including some involved in cancer development. In particular, decreased expression of miR-143 has been reported in various human cancers including colorectal cancer and B-cell lymphomas. The aim of this study was to elucidate the role of miR-143 dysregulation in breast cancer.Methods: Expression levels of human mature microRNAs (miRNAs) were compared with paired breast carcinomas and adjacent normal tissues by TaqMan real-time PCR based expression arrays. Decreased expression of miR-143 was further confirmed in breast cancer cell lines and paired breast tumors and normal adjacent tissues by qRT-PCR. Potential targets of miR-143 were defined. The functional effect of miR-143 and its targets was performed in human breast cancer cell lines to confirm target association.Results: Down-regulation of miR-143 was verified in both human breast cancer cell lines and 80% (12/15) of breast tumors (P < 0.001). DNA methyltranferase 3A (DNMT3A), one of a key enzyme involved in DNA methylation, was defined as a potential target of miR-143 by in-silico analysis. Overexpression of miR-143 in breast cancer cell lines down-regulated expression of DNMT3A, decreased tumor cell growth by MTT assay and soft agar colony formation assay. DNMT3A was demonstrated to be a direct target of miR-143 by luciferase reporter assay. Inverse correlation between DNMT3A protein and miR-143 was found in tumor and normal breast tissues.Conclusions: In this study, we show for the first time in breast cancer that miR-143 specifically targeted DNMT3A and the expression of miR-143 was inversely correlated with DNMT3A expression. Our findings demonstrated that down-regulation of miR-143 and up-regulation of DNMT3A are significant changes in breast tumors. These findings indicate a tumor suppressive role of miR-143 in epigenetic aberration of breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3148.

The Epidemiology, Clinico-Pathologic and Prognostic Characteristics of Triple-Negative Breast Cancer Compared with Non Triple-Negative Breast Cancer

BackgroundTriple negative breast cancers (TNC) are increasingly reported to be associated with higher grade cancers and worse prognosis. TNC are also known to be associated with BRCA mutation. There have also been reports that apart from differences biologically, reproductive, socio-demographics factors such as age of menarche, age of pregnancy, parity, body mass index may influence the development of TNC. The importance of variations in different ethnicities based on studies on Caucasians and African-Americans (AA) have been emphasized. This study aims to look at the tumor characteristics and factors which may influence the presentation and prognosis of TNC in a cohort of Chinese women.Materials and MethodA retrospective review was performed in a prospectively collected database of breast cancer patients between 1996-2007. Clincopathological, epidemiological variables and clinical outcomes were evaluated.ResultsA total of 924 women with breast cancer were included in this cohort of which 142 (8.2%) had TNC and 782 (45.2%) had non TNC. There was no significant difference in age of presentation in both groups (mean age 52.5 vs 52.1 years old). TNC significantly more likely to be associated with higher grade (p<0.01), and are more likely to have lymphovascular invasion (LVI)(p=0.018). There are no significant differences between nodal stage, histological type (invasive vs. in situ), and overall stage at presentation. The median follow up was 4 years. There is no statistically difference in disease free survival (DFS) (3 yr-DFS-61.1% vs. 76%) and Overall survival (OS) (3yr-OS 68.9% vs. 78.5%) although both DFS and OS are worse in TNC. Visceral relapse rate are similar in both groups but a slightly higher rate of bone relapse in TNC group (11.1% vs. 6.9%) though not statistically significant. Although there are no differences in the overall local relapse rate, subanalysis found that after lumpectomy, TNC are more likely to recur (17.7% vs. 3.4%). Higher BMI (p=0.08), shorter duration of breast feed p=0.034), lower parity (p=0.005) are all associated with TNC whereas there are no associations with age of menarche or menopause and age of first pregnancy. 23.7% of a subset of TNC patients who undertook BRCA testing were found to be mutation carriers.DiscussionThe percentage of TNC in this cohort is smaller than that reported in the West. Unlike the West, TNC did not present at a younger age. Although TNC and Non TNC have similar stage of presentation, the DFS and OS are worse in TNC which may be explained by the higher histological grade and likely more aggressive biological characteristics. Local recurrence rate after lumpectomy is also higher in TNC which may be related to higher rate of LVI. There are similarities and differences in associated socio-demographic factors compared to the West and a higher rate of BRCA mutation in TNC. Larger-scale study on different ethnicities will increase our understanding in TNC to achieve more personalized management.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3071.

Strength indices from pQCT imaging predict up to 85% of variance in bone failure properties at tibial epiphysis and diaphysis

Our primary objective was to validate the Bone Strength Index for compression (BSIC) by determining the amount of variance in failure load and stiffness that was explained by BSIC and bone properties at two distal sites in human cadaveric tibiae when tested in axial compression. Our secondary objective was to assess the variance in failure moment and flexural rigidity that was explained by bone properties, geometry and strength indices in the tibial diaphysis when tested in 4-point bending. Twenty cadaver tibiae pairs from 5 female and 5 male donors (mean age 74 yrs, SD 6 yrs) were measured at the distal epiphysis (4 and 10% sites of the tibial length from the distal end) and diaphysis (50 and 66% sites) by peripheral Quantitative Computed Tomography (pQCT; XCT 2000, Stratec). After imaging, we conducted axial compression tests on the distal tibia and 4-point bending tests on the diaphysis. Total bone mineral content and BSIC (product of total area and squared density of the cross-section) at the 4% site predicted 75% and 85% of the variance in the failure load and 52% and 57% in stiffness, respectively. At the diaphyseal sites 80% or more of the variance in failure moment and/or flexural rigidity was predicted by total and cortical area and content, geometry and strength indices corresponding to the axes of bending.

Development of a xenogeneic DNA vaccine program for canine malignant melanoma at the Animal Medical Center

INTRODUCTION

Canine malignant melanoma (CMM) is an aggressive neoplasm treated with surgery and/or fractionated RT; however, metastatic disease is common and chemoresistant. Preclinical and clinical studies by our laboratory and others have shown that xenogeneic DNA vaccination with tyrosinase family members can produce immune responses resulting in tumor rejection or protection and prolongation of survival. These studies provided the impetus for development of a xenogeneic DNA vaccine program in CMM.

MATERIALS AND METHODS

Cohorts of three dogs each received increasing doses of xenogeneic plasmid DNA encoding either human tyrosinase (huTyr; 100/500/1500 mcg), murine GP75 (muGP75; 100/500/1500 mcg), murine tyrosinase (muTyr; 5 dogs each at 100/500 mcg), muTyr+/-HuGM-CSF (9 dogs at 50 mcg muTyr, 3 dogs each at 100/400/800 mcg HuGM-CSF, or 3 dogs each at 50 mcg muTyr with 100/400/800 mcg HuGM-CSF), or 50 mcg MuTyr intramuscularly biweekly for a total of four vaccinations.

RESULTS

The Kaplan-Meier median survival time (KM MST) for all stage II-IV dogs treated with huTyr, muGP75 and muTyr are 389, 153 and 224 days, respectively. Preliminarily, the KM MST for stage II-IV dogs treated with 50 mcg MuTyr, 100/400/800 mcg HuGM-CSF or combination MuTyr/HuGM-CSF are 242, 148 and >402 (median not reached) days, respectively. Thirty-three stage II-III dogs with loco-regionally controlled CMM across the xenogeneic vaccine studies have a KM MST of 569 days. Minimal to mild pain was noted on vaccination and one dog experienced vitiligo. We have recently investigated antibody responses in dogs vaccinated with HuTyr and found 2- to 5-fold increases in circulating antibodies to human tyrosinase.

CONCLUSIONS

The results of these trials demonstrate that xenogeneic DNA vaccination in CMM: (1) is safe, (2) leads to the development of anti-tyrosinase antibodies, (3) is potentially therapeutic, and (4) is an attractive candidate for further evaluation in an adjuvant, minimal residual disease Phase II setting for CMM.

Use of avian influenza vaccination in Hong Kong

Outbreaks of H5N1 highly pathogenic avian influenza (HPAI) that occurred in Hong Kong up until February/March 2002 were controlled by stamping out. With endemic presence of the virus in the region and large daily importation of poultry to Hong Kong, the Administration considered that further risk management measures, in addition to improved biosecurity and enhanced surveillance, were necessary to prevent outbreaks. Vaccination using a killed H5N2 vaccine was evaluated over a 12-month period in the district with the last HPAI cases in the early 2002 outbreak. The vaccination trial showed that farmer-administered killed H5N2 vaccine produced suitable flock antibody responses; vaccinated birds were protected against H5N1 HPAI virus challenge and excreted significantly less H5N1 virus; and vaccination was able to control virus excretion in flocks during field outbreaks. Universal vaccination of local chicken farms was introduced in June 2003 and by the end of 2003 all chickens entering the live poultry markets in Hong Kong were vaccinated by killed H5N2 vaccine. In addition to vaccination, an enhanced biosecurity programme on farms and in live poultry markets and a comprehensive surveillance programme in poultry, wild birds, recreation park birds and pet birds were in place. Vaccination use and performance is closely monitored. This programme was successful in protecting local farms and live poultry markets from H5N1 outbreaks during the regional H5N1 outbreaks in 2004.

Child behaviour and parenting stress in Hong Kong families

OBJECTIVES

To examine parent perception of child behaviour problems and parenting stress in Hong Kong, and to assess the extent to which they are related to socio-demographic factors and the availability of social support.

DESIGN

Cross-sectional survey by using a questionnaire.

SETTING

Maternal and Child Health Centres, Hong Kong.

PARTICIPANTS

Parents of children aged 4 years who were registered with Maternal and Child Health Centres and were living in Hong Kong between September 2002 and February 2003.

MAIN OUTCOME MEASURES

Child behaviour problems and parenting stress.

RESULTS

A total of 1009 questionnaires were returned giving a participation rate of 67.0%. About one tenth of parents were experiencing difficulties with their children's behaviour. Parenting stress and children's behaviour problems were associated with presence or absence of social support. Parenting stress was also associated with household income.

CONCLUSIONS

The prevalence of child behaviour problems in Hong Kong is comparable with international figures. Intervention programmes should be targeted at parents who experience difficulties with their children's behaviour and parenting.

Clinical and echocardiographic follow-up of patients previously treated with dexfenfluramine or phentermine/fenfluramine

CONTEXT

Use of anorexigen therapy is associated with valvular abnormalities, although there is limited information on long-term changes in valvular regurgitation following discontinuation of these agents.

OBJECTIVE

To evaluate changes in valvular regurgitation, valve morphology, and clinical parameters 1 year after an initial echocardiogram in patients previously treated with dexfenfluramine or phentermine/fenfluramine and in untreated controls.

DESIGN AND SETTING

A reader-blinded, multicenter, echocardiographic and clinical 1-year follow-up study at 25 outpatient clinical sites.

PATIENTS

A total of 1142 obese patients (1466 participated in the initial study) who had follow-up echocardiogram; all but 4 had a follow-up medical history and physical examination. Follow-up time from discontinuation of drug to follow-up echocardiogram for 371 dexfenfluramine patients was 17.5 months (range, 13-26 months) and for 340 phentermine/fenfluramine patients was 18.7 months (range, 13-26 months) after discontinuation of drug therapy.

MAIN OUTCOME MEASURE

Change in grade of valvular regurgitation and valve morphology and mobility.

RESULTS

Echocardiographic changes in aortic regurgitation were observed in 8 controls (7 [1.7%] had decreases; 1 [0.2%] had an increase); 29 dexfenfluramine patients (23 [6.4%] had decreases; 6 [1.7%] had increases; P<.001 vs controls); and 15 phentermine/fenfluramine patients (4.5% all decreases; P =.03 vs controls). No statistically significant differences were observed when treated patients were compared with controls for changes in medical history, physical findings, mitral regurgitation, aortic or mitral leaflet mobility or thickness, pulmonary artery systolic pressure, ejection fraction, valve surgery, or cardiovascular events.

CONCLUSION

Progression of valvular abnormalities is unlikely in patients 1 year after an initial echocardiogram and 13 to 26 months after discontinuation of dexfenfluramine and phentermine/fenfluramine.

Divergent consequences of success and failure in japan and north america: an investigation of self-improving motivations and malleable selves

Self-enhancing and self-improving motivations were investigated across cultures. Replicating past research, North Americans who failed on a task persisted less on a follow-up task than those who succeeded. In contrast, Japanese who failed persisted more than those who succeeded. The Japanese pattern is evidence for a self-improving orientation: Failures highlight where corrective efforts are needed. Japanese who failed also enhanced the importance and the diagnosticity of the task compared with those who succeeded, whereas North Americans did the opposite. Study 2 revealed that self-improving motivations are specific to the tasks on which one receives feedback. Study 3 unpackaged the cultural differences by demonstrating that they are due, at least in part, to divergent lay theories regarding the utility of effort. Study 4 addressed the problem of comparing cultures on subjective Likert scales and replicated the findings with a different measure.

Lymphocytes are important in early atherosclerosis

Lymphocytes represent a potentially important proinflammatory cell that localizes to atherosclerotic lesions. To determine whether they contribute to lesion development, atherosclerosis-prone (LDLR(-/-)) mice were crossed with lymphocyte-deficient (RAG1(-/-)) mice to generate double knockout progeny. After 8 weeks on a Western-type diet (WTD), lesion development was reduced by 54% in double knockout mice, as compared with matched LDLR(-/-) controls. However, these significant differences in lesion area gradually subsided as the WTD was continued for 12 and 16 weeks. Consistent with this observation, histological studies determined that lesion initiation and early progression were delayed in RAG1/LDL-R double knockout mice. Differences in lesion area did not correlate with any significant alterations in plasma lipid levels. These studies suggest that lymphocytes play an important role early in atherogenesis.

Valvular abnormalities and cardiovascular status following exposure to dexfenfluramine or phentermine/fenfluramine

CONTEXT

Fenfluramine and dexfenfluramine were voluntarily withdrawn from the market in September 1997 because of reports of an association with heart valve abnormalities. Studies have been limited by lack of comparison with untreated controls.

OBJECTIVE

To evaluate cardiovascular status and the prevalence of valvular abnormalities, as assessed by clinical cardiovascular parameters and echocardiography, in patients treated for obesity with dexfenfluramine or phentermine/fenfluramine.

DESIGN

Reader-blinded controlled study completed in February 1998.

SETTING AND PARTICIPANTS

Twenty-five clinical centers in the United States. Of 1640 enrolled subjects, 1473 were eligible (479 and 455 had taken dexfenfluramine and phentermine/fenfluramine, respectively, continuously for 30 days or more in the previous 14 months, and 539 were untreated matched controls) and provided clinical and echocardiographic data. Mean (SD) age was 47.4 (11.4) years, mean body mass index was 35.0 (7.4) kg/m2, and 74% were women. Mean (SD) duration of therapy was 6.0 (3.3) months (range, 1-18.4 months) in the dexfenfluramine group, and 11.9 (10.4) months (range, 1.4-63 months) in the phentermine/fenfluramine group, while the untreated group had no anorexigen use during the previous 5 years.

MAIN OUTCOME MEASURES

Cardiovascular signs and symptoms; echocardiographic evidence of aortic (AR) or mitral (MR) regurgitation according to US Food and Drug Administration (FDA) criteria (AR > or = mild or MR > or = moderate) and by grade; tricuspid and pulmonic valve regurgitation; and aortic, mitral, and tricuspid valve leaflet mobility and thickness, for treated vs untreated subjects.

RESULTS

Cardiovascular signs and symptoms were similar among anorexigen-treated and untreated subjects. Prevalence rates and relative risk (RR) of AR were significantly increased in anorexigen-treated patients and were 8.9% in the dexfenfluramine group (RR, 2.18; 95% confidence interval [CI], 1.32-3.59), 13.7% in the phentermine/fenfluramine group (RR, 3.34; 95% CI, 2.09-5.35), and 4.1% in the untreated group (P<.001). No statistically significant differences in prevalence were observed for MR, thickening or decreased mobility of any valve leaflet, calculated pulmonary artery systolic pressure, or left ventricular ejection fraction. Serious cardiac events (including myocardial infarction, congestive heart failure, or ventricular arrhythmia) occurring at any time were not statistically different in treated and untreated subjects (dexfenfluramine, 9.0%; phentermine/fenfluramine, 4.0%; and untreated, 8.4%); and following anorexigen treatment were uncommon (dexfenfluramine, 2.3%; phentermine/fenfluramine, 2.4%, and untreated, 3.3%, when adjusted for the median start date of anorexigen use).

CONCLUSIONS

Our data indicate that use of dexfenfluramine and phentermine/fenfluramine is associated with an increase in the prevalence of AR using FDA echocardiographic criteria, but was not associated with an increase in the prevalence of MR using FDA criteria or with serious cardiac events.

In planta expression of HIV-1 p24 protein using an RNA plant virus-based expression vector

Plant viruses show significant potential as expression vectors for the production of foreign proteins (e.g., antigens) in plants. The HIV-1 p24 nucleocapsid protein is an important early marker of HIV infection and has been used as an antigen in the development of HIV vaccines. Toward developing a plant-based expression system for the production of p24, we have investigated the use of a (positive)-strand RNA plant virus, tomato bushy stunt virus (TBSV), as an expression vector. The HIV p24 open reading frame (ORF) was introduced into a cloned cDNA copy of the TBSV genome as an in-frame fusion with a 5'-terminal portion of the TBSV coat protein ORF. In vitro-generated RNA transcripts corresponding to the engineered virus vector were infectious when inoculated into plant protoplasts; Northern and Western blot analyses verified the accumulation of a predicted p24-encoding viral subgenomic mRNA and the production of p24 fusion product. Whole-plant infections with the viral vector led to the accumulation of p24 fusion protein in inoculated leaves, which cross-reacted with p24-specific antibodies, thus confirming the maintenance of key antigenic determinants. This study is the first to demonstrate that TBSV can be engineered to express a complete foreign protein of clinical importance. Strategies for optimizing protein yield from this viral vector are discussed.

Traumatic vertebral arterial dissection and vertebrobasilar arterial thrombosis successfully treated with endovascular thrombolysis and stenting

A case of traumatic extracranial vertebral arterial dissection leading to vertebrobasilar thrombosis and respiratory compromise requiring mechanical ventilation was managed with intraarterial thrombolysis and stenting of the vertebral intimal dissection. In contrast to similar, previously reported cases, this critically ill patient made a full recovery, returning to his job as a secondary school teacher.

The BCL-6 proto-oncogene controls germinal-centre formation and Th2-type inflammation

Structural alterations of the promoter region of the BCL-6 proto-oncogene represent the most frequent genetic alteration associated with non-Hodgkin lymphoma, a malignancy often deriving from germinal-centre B cells. The BCL-6 gene encodes a zinc-finger transcriptional repressor normally expressed in both B cells and CD4+ T cells within germinal centres, but its precise function is unknown. We show that mice deficient in BCL-6 displayed normal B-cell, T-cell and lymphoid-organ development but have a selective defect in T-cell-dependent antibody responses. This defect included a complete lack of affinity maturation and was due to the inability of follicular B cells to proliferate and form germinal centres. In addition, BCL-6-deficient mice developed an inflammatory response in multiple organs characterized by infiltrations of eosinophils and IgE-bearing B lymphocytes typical of a Th2-mediated hyperimmune response. Thus, BCL-6 functions as a transcriptional switch that controls germinal centre formation and may also modulate specific T-cell-mediated responses. Altered expression of BCL-6 in lymphoma represents a deregulation of the pathway normally leading to B cell proliferation and germinal centre formation.

Measurement of a cross-sectional area of normal and stenotic arteries with videodensitometric quantitative arteriography and intravascular ultrasound

RATIONALE AND OBJECTIVES

A videodensitometric technique that allows measurement of absolute cross-sectional area of any complex lesion was compared with an intravascular ultrasound (US) technique.

METHODS

Stenotic devices (10-15 mm long) with cross sections of different shapes were placed in the distal aortas of five anesthetized pigs (weight, 40-50 kg). The stenotic devices were imaged by using an intravascular US probe after power injection of contrast material.

RESULTS

A comparison of actual areas and measured cross-sectional areas of the stenotic devices showed that videodensitometry and intravascular US produced better results than edge-detection techniques for both unsubtracted and temporal subtraction images.

CONCLUSION

These data suggest that the videodensitometric technique can be used to measure absolute cross-sectional areas of arteries with different shapes.

Conformation and molecular topography of the N-terminal segment of surfactant protein B in structure-promoting environments

Although the effects of surfactant protein B (SP-B) on lipid surface activity in vitro and in vivo are well known, the relationship between molecular structure and function is still not fully understood. To further characterize protein structure-activity correlations, we have used physical techniques to study conformation, orientation, and molecular topography of N-terminal SP-B peptides in lipids and structure-promoting environments. Fourier transform infrared (FTIR) and CD measurements of SP-B1-25 (residues 1-25) in methanol, SDS micelles, egg yolk lecithin (EYL) liposomes, and surfactant lipids indicate the peptide has a dominant helical content, with minor turn and disordered components. Polarized FTIR studies of SP-B1-25 indicate the long molecular axis lies at an oblique angle to the surface of lipid films. Truncated peptides were similarly examined to assign more accurately the discrete conformations within the SP-B1-25 sequence. Residues Cys-8-Gly-25 are largely alpha-helix in methanol, whereas the N-terminal segment Phe-1-Cys-8 had turn and helical propensities. Addition of SP-B1-25 spin-labeled at the N-terminal Phe (i.e., SP-B1-25) to SDS, EYL, or surfactant lipids yielded electron spin resonance spectra that reflect peptide bound to lipids, but retaining considerable mobility. The absence of characteristic radical broadening indicates that SP-B1-25 is minimally aggregated when it interacts with these lipids. Further, the high polarity of SP-B1-25 argues that the reporter on Phe-1 resides in the headgroup of the lipid dispersions. The blue-shift in the endogenous fluorescence of Trp-9 near the N-terminus of SP-B1-25 suggests that this residue also lies near the lipid headgroup. A summary model based on the above physical experiments is presented for SP-B1-25 interacting with lipids.

A synthetic segment of surfactant protein A: structure, in vitro surface activity, and in vivo efficacy

Surfactant protein A (SP-A) is a 248-residue, water-soluble, lipid-associating protein found in lung surfactant. Analysis of the amino acid sequence using the Eisenberg hydrophobic moment algorithm predicts that the SP-A segment spanning residues 114-144 has high hydrophobic moments, typical of lipid-associating amphipathic domains. The secondary structure, in vitro surface activity and in vivo lung activity of this SP-A sequence were studied with a 31-residue synthetic peptide analog (A114-144). Analysis of the secondary structure using circular dichroism and Fourier transform infrared spectroscopy indicated association with lipid dispersions and a dominant helical content. Surface activity measurements of A114-144 with surfactant lipid dispersions and the hydrophobic surfactant proteins B and C (SP-B/C) showed that A114-144 enhances surface activity under conditions of dynamic compression and respreading on a Langmuir/Wilhelmy surface balance. Synthetic surfactant dispersions containing A114-144 improved lung compliance in spontaneously breathing, 28-d premature rabbits to a greater degree than surfactant dispersions with synthetic SP-B/C and synthetic surfactant lipids alone. These observations indicate that inclusion of A114-144 may improve synthetic preparations currently used for surfactant replacement therapy.

Detection of epidermal growth factor receptor in inflammatory periapical lesions

Epithelial cell proliferation is often observed in periapical lesions of endodontic origin. The mechanisms which stimulate the epithelial cell rests of Malassez to proliferate are not understood fully. Fifteen inflammatory periapical lesions (10 granulomas and five cysts) obtained from periapical surgery and six additional periapical lesions (four granulomas and two cysts) collected from extracted teeth were examined using immunohistochemical staining and 125I-EGF (epidermal growth factor) binding assay to detect the presence of epidermal growth factor receptor. The results indicated that the periapical lesions without epithelial cell proliferation had a weak immunoperoxidase staining or low specific binding of 125I-EGF. In contrast, the periapical lesions with epithelial cell proliferation and cyst formation exhibited a strong immunoperoxidase staining in the epithelial cells or high specific binding of 125I-EGF.

Synthesis, secondary structure and folding of the bend region of lung surfactant protein B

Previous theoretical analysis of the primary structure of lung surfactant protein SP-B indicates a disulfide-linked, hydrophobic midsequence that forms a hairpin-like motif. Here, we experimentally investigate the secondary structure of the disulfide-stabilized bend region by synthesizing two 12-residue analogs of the SP-B midsequence. The native peptide has the same sequence for residues 35 to 46 as native human SP-B, while, in the second mimic peptide, Leu40 and Val41 were replaced with D-Ser and L-His. Both peptides contain cysteine residues at the N- and C-terminus (Cys35 and Cys46, respectively). Oxidation/reduction experiments with fast atom bombardment mass spectrometry showed mass shifts of approximately 2 daltons, consistent with the oxidized peptides existing in solution as monomers, each with one internal disulfide bond (Cys35-Cys46). Since circular dichroism and Fourier-transform infrared measurements show that both peptides assume turn conformations in structure-promoting solvents such as trifluoroethanol (TFE), a structural model is proposed in which Cys35 and Cys46 are brought in close apposition through an internal bend in the peptide. Consistent with this model are electron spin resonance (ESR) results of the mimic peptide nitroxide spin-labeled at Cys35 and Cys46. For the double spin-labeled mimic peptide in TFE. ESR spectra indicated broadening characteristic of either radical interactions or decreased mobility, or both. Increases in radical interactions for the double spin-labeled mimic peptide would be expected for Cys35 and Cys46 approaching within 14 A in structure-promoting solvents, while decreases in spin-label mobility could be due to the formation of a loop. Based on these observations with peptide analogs, residues 35 to 46 probably form a similar bend in the full-length protein.

An unusual presentation of urinary retention

Patients with urinary retention frequently present to the emergency department (ED) for evaluation and treatment. Urinary retention is seen most often in males secondary to mechanical causes. However, other etiologies must be considered. We present an unusual case of a 35-year-old male who developed postcoital urinary retention secondary to urogenital diaphragm spasm.

Antivirals that target the amino-terminal domain of HIV type 1 glycoprotein 41

Functional and structural studies were made to assess whether a class of antiviral agents targets the N-terminal domain of the glycoprotein 41,000 (gp41) of human immunodeficiency virus type 1 (HIV-1). Previous experiments have shown that the amino-terminal peptide (FP-I; 23 amino acids, residues 519-541) of HIV-1 gp41 is cytolytic to both human erythrocytes (non-CD4+ cells) and Hut-78 cells (CD4+ lymphocytes). Accordingly, FP-I-induced hemolysis may be used as a surrogate assay for evaluating the role of the N-terminal gp41 domain in HIV-cell interactions. Here, we studied the blocking of FP-I-induced lysis of erythrocytes by the following anti-HIV agents: (1) IgG [i.e., anti-(518-541) IgG] raised to an immunoconjugate of Arg-FP-I, (2) apolipoprotein A-1 (apo A-1) and a peptide based on apo A-1, (3) dextran sulfate, (4) gp41 peptide (residues 637-666), and (5) anionic human serum albumins. Dose-response curves indicated that their relative potency in inhibiting FP-I-induced hemolysis was approximately correlated with their previously reported anti-HIV activity. Electron spin resonance (ESR) studies showed that FP-I spin labeled at the N-terminal alanine binds to anti-(518-541) IgG, dextran sulfate, and anionic albumins. The high in vitro antiviral activity and low cytotoxicity of these agents suggest that blocking membrane-FP-I interactions offers a novel approach for AIDS therapy or prophylaxis.

Neuromuscular transmission in amyotrophic lateral sclerosis

The functional and structural characteristics of the neuromuscular junction were studied in anconeus muscle biopsies of 10 patients with amyotrophic lateral sclerosis (ALS). Intracellular recordings revealed decreased amplitudes of miniature endplate potentials (MEPPs). The MEPP frequencies were highly variable in ALS patients but the average MEPP frequency was not different from that of control patients. The mean quantal content of endplate potentials (m), the mean quanta available for immediate release (n), and the mean quantal stores (N) were all decreased. In contrast, the mean probability of quantal release (p) was normal and the mean probability of quantal store release (P) was surprisingly high at the majority of ALS endplates. Histologic evidence of denervation and small or absent nerve terminals were observed in all ALS patients. These functional and structural abnormalities of the neuromuscular junction may explain the fatigability and the electromyographic evidence of impaired neuromuscular transmission often encountered in ALS patients.

Analysis of anticholinesterase-induced neuromuscular transmission failure

To define the underlying mechanism of neuromuscular transmission failure induced by anticholinesterases, we simultaneously performed surface recordings of compound muscle action potentials (CMAPs) and intracellular recordings of miniature end-plate potentials (MEPPs), miniature end-plate current (MEPCs), and end-plate potential (EPPs) in rat diaphragms exposed in vitro to 1 x 10(-4) to 2 x 10(-2) mmol/L neostigmine methylsulfate. At low concentrations of neostigmine, repetitive stimulation of the phrenic nerve resulted in decrement followed by complete recuperation of CMAP amplitudes. This bimodal pattern was associated with maximal end-plate depolarization at the beginning of the stimulation period, increased MEPP amplitudes, and prolonged time constants of MEPC decays. Higher concentrations of neostigmine resulted in a unimodal decline of amplitudes of CMAPs and EPPS, reduced MEPP amplitudes, and a double exponential time course of MEPC decays. These results indicate that low concentrations of anticholinesterases impaired neuromuscular transmission by producing transient depolarization of the end-plate region. Higher concentrations induced desensitization and direct blockade of the end-plate receptor channel, probably in its open conformation.

Effect of cigarette smoking on salivary epidermal growth factor (EGF) and EGF receptor in human buccal mucosa

The mouth acts as a primary target for cigarette smoke which is associated with several oral diseases and cancer. The present study investigated the effect of cigarette smoking on salivary EGF and the buccal EGF receptor. Samples of whole saliva and buccal biopsy were obtained from 15 healthy volunteers (10 smokers and 5 non-smokers). The smokers smoked 20 or more cigarettes/day for more than 5 years. Salivary cotinine (a major metabolite of nicotine) was determined by radioimmunoassay (RIA). The salivary cotinine level was consistent with the self-reported smoking status (smokers, 106-530 ng/ml saliva; non-smokers, < 2 ng/ml saliva). As compared to the non-smokers, the salivary EGF concentration (determined by RIA) was 32% lower in those smokers whose salivary cotinine level was 250 ng/ml or higher (non-smokers, 2.21 +/- 0.16; smokers, 1.57 +/- 0.09 ng/ml saliva; mean +/- S.E.M., P < 0.01). There was no significant difference in 125I-labeled EGF binding to the buccal receptor between the two groups. However, EGF stimulated the autophosphorylation of a 170-kDa protein band in the sample of non-smokers, but not in the smokers. The immunoblot analysis using anti-EGF receptor antibody indicated that the smoking-related deficiency in EGF receptor autophosphorylation was due to the functional alteration of the receptor proteins. In conclusion, cigarette smoking reduces the salivary EGF level and impairs the function of buccal EGF receptor, which may be associated with the pathology of smoking-related oral disease.

Heritability of dark pulse triggering of paradoxical sleep in rats

A previous study showed that albino Lewis (L) rats could be triggered into paradoxical sleep (PS) by dark pulse stimulation, i.e., turning off cage lights, whereas brown Norway (BN) rats showed no evidence of PS triggering by dark pulses (2). The transmission of the PS triggering behavior was studied in L x [L x BN]F1 hybrid backcross (BC) animals. Albino BC rats increased PS% during 5-minute dark pulses to three times the average PS% for the preceding 5 minutes of lights-on. In contrast, no significant PS triggering was observed in pigmented BC rats. These data support the hypothesis that PS triggering by dark pulse stimulation is related to albinism in these rat strains. The absence of a connection between PS triggering and total daily amounts of PS suggests independent genetic transmission of these two parameters.

[Effect of light on total micro-bilirubin values in vitro]

In order to elucidate the effect of light on total bilirubin values in vitro, 616 capillary blood samples were collected from jaundiced newborn infants at the nursery of Veterans General Hospital-Taipei. Samples were divided into 3 groups: 1. Phototherapy light group-133 samples were irradiated with blue fluorescent light (spectral irradiance 425-475 nm = 4 mu watt/cm2/nm); 2. Room light group-202 samples were irradiated with white fluorescent light (spectral irradiance 425-475 nm = 0.2 mu watt/cm2/nm); 3. Dark group-the last 215 samples were placed in the dark. Total bilirubin values were checked with spectrophotometry, at 0, 2, 4, 6, 24 and 48 hours after being placed in different environments. Total bilirubin values varied significantly in different light source and time groups (p less than 0.0001), plus both had statistical interactions (p less than 0.0001). There were significant decreases in the bilirubin values of the phototherapy group beginning at 2 hours (p less than 0.05), and in the room light group beginning at 6 hours (p less than 0.05), but there was no change in the dark group. We conclude that blood samples for total bilirubin values should not be placed under the light of phototherapy even 2 hours. If blood samples are exposed to room light inevitably, it is safe to be checked within 4 hours. If immediate measurements are unavailable, the samples can be placed in a dark environment allowing the values to remain unchanged for 48 hours.