Mechanisms of Intrinsic Radioresistance in Breast Cancer Identify Potential Therapeutic Vulnerabilities

PURPOSE/OBJECTIVE(S)

Clinical management of breast cancer (BC) includes radiation therapy (RT) for most women, though the molecular mechanisms that underly RT response and intrinsic radioresistance are poorly understood. Both in vitro and in vivo models aid in our understanding of radiobiology, and we hypothesized that transcriptional changes caused by radiation in vitro in BC cell lines would be recapitulated in an in vivo mouse xenograft model and uncover targetable mechanisms of radioresistance in BC.

MATERIALS/METHODS

Radiosensitivity was measured with clonogenic survival assays in 16 cell lines. RNA-seq experiments in vitro and in vivo were performed in an RT resistant (SUM-159) and RT sensitive (ZR-75) cell line 24 hrs after 4 Gy or after 2 Gy x 6 fractions, respectively. Differentially expressed genes (DEGs) were identified from RNA-seq data with DeSeq2 followed by pathway analysis with iPathwayGuide.

RESULTS

RT sensitivity was subtype independent in 16 BC cell lines, with SUM-159 radioresistant (SF 0.88) and ZR-75-1 radiosensitive (SF 0.29). There were 75 unique pathways that were significantly altered after RT in SUM-159 cells (53 pathways in vivo only, 36 pathways in vitro only, 14 both conditions; adjusted p-value < 0.05) and 85 unique pathways that were significantly altered after RT in ZR-75-1 cells (16 pathways in vivo only, 72 in vivo only, 3 both conditions; adjusted p-value < 0.05). Pathways that were significantly affected in both cell lines exclusively in the in vitro condition include canonical RT response pathways such as cell cycle, cellular senescence, and DNA replication, though the direction of DEGs were opposite in the two cell lines for each of these pathways. The IL-17 signaling pathway was significantly altered for both cell lines in vivo. Of the pathways that were significantly altered in both conditions for SUM-159 cells, inflammation, including chemokine signaling pathway and cytokine-cytokine receptor interaction, were among the most significant. Significantly more cytokines were upregulated following RT in vivo than in vitro. Cytokines were not upregulated in ZR-75-1 cells in vitro or in vivo.

CONCLUSION

Taken together, the significant changes in the IL-17 pathway and the upregulation of cytokines only in vivo indicate a potential of the tumor microenvironment in the in vivo condition that the in vitro condition lacks. Increased heterogeneity in vivo relative to in vitro may also explain the absence of several canonical RT response pathways in the in vivo conditions for each cell line. Notably, the opposite direction of DEG changes in the canonical RT response pathways between the 2 cell lines with disparate radiosensitivity levels may point to important biologic vulnerabilities that may be targeted in the resistant SUM-159 cells. Future studies are underway using additional BC cell lines and single-cell analysis to better understand RT response heterogeneity.

Promoter methylation of ADAMTS1 and BNC1 as potential biomarkers for early detection of pancreatic cancer in blood

BACKGROUND

Despite improvements in cancer management, most pancreatic cancers are still diagnosed at an advanced stage. We have recently identified promoter DNA methylation of the genes ADAMTS1 and BNC1 as potential blood biomarkers of pancreas cancer. In this study, we validate this biomarker panel in peripheral cell-free tumor DNA of patients with pancreatic cancer.

RESULTS

Sensitivity and specificity for each gene are as follows: ADAMTS1 87.2% and 95.8% (AUC = 0.91; 95% CI 0.71-0.86) and BNC1 64.1% and 93.7% (AUC = 0.79; 95% CI 0.63-0.78). When using methylation of either gene as a combination panel, sensitivity increases to 97.3% and specificity to 91.6% (AUC = 0.95; 95% CI 0.77-0.90). Adding pre-operative CA 19-9 values to the combined two-gene methylation panel did not improve sensitivity. Methylation of ADAMTS1 was found to be positive in 87.5% (7/8) of stage I, 77.8% (7/9) of stage IIA, and 90% (18/20) of stage IIB disease. Similarly, BNC1 was positive in 62.5% (5/8) of stage I patients, 55.6% (5/9) of stage IIA, and 65% (13/20) of patients with stage IIB disease. The two-gene panel (ADAMTS1 and/or BNC1) was positive in 100% (8/8) of stage I, 88.9% (8/9) of stage IIA, and 100% (20/20) of stage IIB disease. The sensitivity and specificity of the two-gene panel for localized pancreatic cancer (stages I and II), where the cancer is eligible for surgical resection with curative potential, was 94.8% and 91.6% respectively. Additionally, the two-gene panel exhibited an AUC of 0.95 (95% CI 0.90-0.98) compared to 57.1% for CA 19-9 alone.

CONCLUSION

The methylation status of ADAMTS1 and BNC1 in cfDNA shows promise for detecting pancreatic cancer during the early stages when curative resection of the tumor is still possible. This minimally invasive blood-based biomarker panel could be used as a promising tool for diagnosis and screening in a select subset of high-risk populations.

Lung Cancer Screening and Epigenetics in African Americans: The Role of the Socioecological Framework

Lung cancer is the leading cause of cancer morbidity and mortality in the U.S. and racial/ethnic minorities carry the greatest burden of lung cancer disparities with African Americans (AAs) impacted disproportionately. Inequities in lung cancer health disparities are often associated with multiple bio-behavioral and socio-cultural factors among racial/ethnic minorities. Epigenetic research has advanced the understanding of the intersectionality between biological and socio-cultural factors in lung cancer disparities among AAs. However, gaps exist in the engagement of diverse populations in epigenetic lung cancer research, which poses a challenge in ensuring the generalizability and implementation of epigenetic research in populations that carry an unequal cancer burden. Grounding epigenetic lung cancer research within a socio-ecological framework may prove promising in implementing a multi-level approach to community engagement, screening, navigation, and research participation among AAs. The University of Illinois Cancer Center (UI Cancer Center) is employing an evidence–based (EB) model of community/patient engagement utilizing the socio-ecological model (SEM) to develop a culturally sensitive epigenetic lung cancer research program that addresses multiple factors that impact lung cancer outcomes in AAs. By implementing epigenetic research within a group of Federally Qualified Health Centers (FQHCs) guided by the SEM, the UI Cancer Center is proposing a new pathway in mitigating lung cancer disparities in underserved communities. At the individual level, the framework examines tobacco use among patients at FQHCs (the organizational level) and also tailors epigenetic research to explore innovative biomarkers in high risk populations. Interpersonal interventions use Patient Navigators to support navigation to EB tobacco cessation resources and lung cancer screening. Community level support within the SEM is developed by ongoing partnerships with local and national partners such as the American Lung Association (ALA) and the American Cancer Society (ACS). Lastly, at the policy level, the UI Cancer Center acknowledges the role of policy implications in lung cancer screening and advocates for policies and screening recommendations that examine the current guidelines from the United States Preventive Services Task Force (USPTF).

Abstract 3308: Urine epigenetic biomarkers for NSCLC diagnosis

Purpose:

The National Lung Cancer Screening Trial showed mortality reduction on patients with NSCLC by the use of Low-dose CT screening. The study exhibits an unreasonably high false positive rate of 96.6%, which can to lead to significant morbidity and mortality from unnecessary tests. This study aim to determine if methylated promoter regions of a panel of genes that are correlated with Non-Small Cell Lung Cancer can be detected in urine from patients with lung cancer versus those without.

Materials and Methods:

We conducted a prospective case-control study recruiting subjects from the Lung Cancer Spore Trial. Urine and pre-operative CT scans were obtained from all patients. We processed the urine using the Methylation on Beads assay to isolate and bisulfite treat circulating DNA and then employed Quantitative Methylation Specific Real-Time PCR to detect promoter methylation status of the genes: CDO1, TAC1, HOXA7, HOXA9, SOX17 and ZFP42. Sensitivity, specificity, PPV and NPV values were calculated for each gene methylation status.

Results:

34 patients were studied, including 23 patients with NSCLC and 11 patients with benign non-cancerous lesions. The sensitivity, specificity, PPV and NPV values for lung cancer detection in urine are shown in Table 1. Sensitivities ranged 43-96%, Specificities 64-91%, PPV 71-100% and NPV 40-67%. Promoter methylation of the gene panel CDO1, TAC1, HOXA7, HOXA9, SOX17 and ZPF42 has a 78% sensitivity, 91% specificity, 95% PPV and 67% NPV for lung cancer detection.

Conclusion:

Our study suggests that urine can provide a highly sensitive and specific non-invasive route for lung cancer detection. These results are very promising and could potentially reduce unnecessary morbidity and mortality in people undergoing screening for NSCLC by use of a non-invasive method that could be more accessible on primary care centers. However, further studies and validation with larger sample sizes and different populations are necessary before its application to clinical practice.

Patients with positive gene methylation from urine samples and its accuracy for NSCLC detection.Cancer (n=23)Cancer (n=23)Control (n=11)Control (n=11)nSensitivitynSpecificityPPVNPVCDO114611919353TAC11565010010058SOX1716704648050HOXA711483737940HOXA910431919143ZPF4222969187167Panel of genes18781919567

Citation Format: Lane Lerner, Lily Zheng, Anastasia Kottorou, Chen Chen, Tomoaki Ito, Kristen Rodgers, Beverly Lee, Robert Winn, Enrico Benedetti, Tza- Huei Wang, Malcolm V. Brock, James G. Herman, Alicia Hulbert. Urine epigenetic biomarkers for NSCLC diagnosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3308.

Abstract 5515: Ras-like estrogen-regulated growth-inhibitory gene (RERG): A novel biomarker and potential therapeutic target for women with lung cancer

Background: Lung cancer is the second most common cancer diagnosed in women. In fact, twice as many women will die from lung cancer compared to breast cancer, the key risk factor being tobacco use. Hence, there is a need to identify new molecular biomarkers to aid in early detection and develop new therapeutic strategies in tobacco-related lung cancer. Ras-like Estrogen-Regulated Growth-Inhibitory Gene (RERG) is a member of the Ras superfamily of GTPases that play an important role in cellular processes such as proliferation, differentiation, and apoptosis. Unlike other members of the Ras superfamily members of proto-oncogenes, RERG functions as a tumor suppressor.

Objective: To investigate the utility of RERG expression as a novel biomarker and a potential therapeutic target in lung cancer.

Results: In silico analysis of The Cancer Genome Atlas (TCGA) lung cancer datasets revealed a significant downregulation of RERG expression in lung tumors. Furthermore, reduced expression of RERG in lung tumors was also observed to be correlated with poor prognosis as determined by Kaplan-Meier survival analysis. Evaluation of formalin-fixed, paraffin-embedded (FFPE) human lung cancer tissues and fresh frozen lung tumor tissues corroborated our in silico observations. Most notably, tobacco smoke was identified to be associated with decreased RERG expression in lung tumors. The most intriguing observation from this study is the significant decrease of RERG expression in female smokers as a result of promoter hypermethylation.

Conclusion: Taken together, these findings suggest that RERG may represent a potential biomarker in lung cancer, particularly among smokers. Further investigation would focus on the mechanism of RERG loss and its influence on lung tumor development, particularly in female smokers.

Citation Format: Michelle Van Scoyk, Sreedevi Avasarala, Pei-Ying Wu, Yanlin Su, Lane Lerner, Alicia Hulbert, Kamesh Bikkavilli, Robert A. Winn. Ras-like estrogen-regulated growth-inhibitory gene (RERG): A novel biomarker and potential therapeutic target for women with lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5515.

Lung cancer early detection and health disparities: the intersection of epigenetics and ethnicity

Lung cancer is the most prominent cause of cancer-related mortality. Significant disparities in incidence and outcome characterize the disease's manifestations among ethnically and racially diverse populations. Complete surgical resection is the most effective curative treatment. However, success relies on early tumor detection. The National Lung Cancer Screening trial showed that lung cancer related mortality can be reduced by the use of low-dose CT (LDCT) screening. However, this test is plagued by a high false positive rate of 97% and the device itself is limited to designated cancer centers due to its expense and size. This restriction makes it difficult for underserved groups to access LDCT screening, the current standard of care. Highly sensitive and specific epigenetic DNA methylation-based biomarkers have the potential to work independently or in conjunction with LDCT screening to identify early-stage tumors. These tests could reduce unnecessary invasive confirmatory diagnostic tests and their associated morbidity and mortality. These tests also have the opportunity to bring lung cancer screening to the community thereby reducing unequal accessibility. However, epigenetic alterations are closely linked to the interplay between hereditary and environmental factors such as diet, lifestyle, ethnic ancestry, toxin exposure, residential segregation, and disparate community support structures. Despite this, the overwhelming number of early detection DNA methylation biomarker studies to date have either failed to control for ethnicity or have employed heavily Caucasian-biased patient cohorts. This review seeks to summarize the literature related to the early detection of lung cancer through molecular biomarkers among different ethnicities. Ethnical specific epigenetic biomarkers have the potential to be the first step towards an accessible, available personalized medicine approach to cancer through liquid biopsy.

Increased pro-inflammatory activity and impairment of human monocyte differentiation induced by in vitro exposure to cigarette smoke

Cigarette smoking (CS) is associated with a variety of human pathologies including cardiovascular disease and cancer. Human monocytes are prevalent in oral and respiratory mucosa and may be affected by exposure to CS, which induces oxidative stress. As a result, up-regulation of nuclear factor-kappaB (NF-kappaB) may occur. Our aims were to analyze a possible regulatory effect of CS on NF-kappaB activity in human monocytes. Human monocyte cell lines were exposed to CS in vitro. Our findings show that in vitro exposure to CS did not affect viability of human monocytes and was associated with increased production and secretion of IL-8 and up-regulation of certain C-C chemokines. Inhibition of NF-kappaB with curcumin or parthenolide resulted in a decrease of IL-8 secretion. CS also impaired the differentiation of monocytes. However, induced secretion of IL-8 from differentiated monocytes was not impaired. Our results indicate that exposure to CS stimulates pro-inflammatory activity of human monocytes through the activation of NF-kappaB pathway and also interferes with monocyte differentiation, which could play a role in the carcinogenic effects of cigarette smoking.

Creation of genome-wide protein expression libraries using random activation of gene expression

Here we report the use of random activation of gene expression (RAGE) to create genome-wide protein expression libraries. RAGE libraries containing only 5 x 10(6) individual clones were found to express every gene tested, including genes that are normally silent in the parent cell line. Furthermore, endogenous genes were activated at similar frequencies and expressed at similar levels within RAGE libraries created from multiple human cell lines, demonstrating that RAGE libraries are inherently normalized. Pools of RAGE clones were used to isolate 19,547 human gene clusters, approximately 53% of which were novel when tested against public databases of expressed sequence tag (EST) and complementary DNA (cDNA). Isolation of individual clones confirmed that the activated endogenous genes can be expressed at high levels to produce biologically active proteins. The properties of RAGE libraries and RAGE expression clones are well suited for a number of biotechnological applications including gene discovery, protein characterization, drug development, and protein manufacturing.

Clinical, epidemiological, and microbiological features of Vibrio vulnificus biogroup 3 causing outbreaks of wound infection and bacteraemia in Israel. Israel Vibrio Study Group

BACKGROUND

Vibrio vulnificus is a gram-negative bacterium that causes septicaemia and wound infection. Cases occur sporadically, and no previous outbreaks due to a common source or a clonal strain have been reported. In the summer and autumn of 1996 and 1997, an outbreak of invasive V. vulnificus infection occurred in Israel in people who had recently handled fresh, whole fish purchased from artificial fish-ponds.

METHODS

We reviewed clinical and epidemiological information, and undertook an environmental investigation to assess disease characteristics, modes of transmission, phenotypic characteristics of the bacterium, and fish-marketing policy. The clonal nature of 19 isolates was studied by biotyping, pulsed-field gel electrophoresis, and restriction-fragment length polymorphism (RFLP) analysis of a PCR fragment.

FINDINGS

During 1996-97, 62 cases of wound infection and bacteraemia occurred. 57 patients developed cellulitis, four had necrotising fasciitis, and one developed osteomyelitis. In all cases, the fish were cultivated in inland fish-ponds. In the summer of 1996, fish-pond managers initiated a new marketing policy, in which fish were sold alive instead of being packed in ice. Phenotypically, the isolates had five atypical biochemical test results. The isolates were non-typeable by pulsed-field gel electrophoresis, and all had the same PCR-RFLP pattern which had not been seen previously.

INTERPRETATION

The cause of the outbreak was a new strain of V. vulnificus, classified as biogroup 3. A new fish-marketing policy that began in 1996 may have exposed susceptible people to the organism.

A convenient microscale colorimetric method for terminal galactose on immunoglobulins

A new approach for quantitative determination of terminal galactose (Gal) residues of immunoglobulins was developed by combining exoglycosidase digestion with the classical colorimetric estimation of reducing sugars. The ferricyanide colorimetric method was modified to increase the stability of the chromophore (Prussian blue) and adapted to determine the amount of terminal Gal residues present in immunoglobulins. The method involves the release of covalently bound Gal from immunoglobulins by Diplococcus pneumoniae beta-D-galactosidase (specific for beta(1,4) linked galactose), removal of the glycoprotein and enzyme from the reaction mixture by heat denaturation or ethanol precipitation, followed by colorimetric measurement of the released sugar using the ferricyanide assay. The ferricyanide method was modified to enhance the solubility and stability of the chromophore by increasing the concentration of aqueous sulfuric acid and sodium dodecyl sulfate (SDS). The linear range of the modified method was from approximately 11 to 111 microM Gal. Typical variation in assay results was on the order of 5%. Using the modified method, the terminal Gal content of a recombinant chimeric monoclonal antibody (anti-CD20, rIgG) expressed in Chinese hamster ovary (CHO) cells was determined and evaluated for batch-to-batch consistency. The method was used to optimize pH, time, temperature, and enzyme concentration for beta-galactosidase digestion for maximal release of terminal Gal residues from rIgG.

The effect of O-fucosylation on the first EGF-like domain from human blood coagulation factor VII

The first epidermal growth factor-like domain (EGF-1) from blood coagulation factor VII (FVII) contains two unusual O-linked glycosylation sites at Ser-52 and Ser-60. We report here a detailed study of the effect of O-fucosylation at Ser-60 on the structure of FVII EGF-1, its Ca2+-binding affinity, and its interaction with tissue factor (TF). The in vitro fucosylation of the nonglycosylated FVII EGF-1 was achieved by using O-fucosyltransferase purified from Chinese hamster ovary cells. Distance and dihedral constraints derived from NMR data were used to determine the solution structures of both nonglycosylated and fucosylated FVII EGF-1 in the presence of CaCl2. The overall structure of fucosylated FVII EGF-1 is very similar to the nonfucosylated form even for the residues near the fucosylation site. The Ca2+ dissociation constants (Kd) for the nonfucosylated and fucosylated FVII EGF-1 were found to be 16.4 +/- 1.8 and 8.6 +/- 1.4 mM, respectively. The FVII EGF-1 domain binds to the extracellular part of TF with a low affinity (Kd approximately 0. 6 mM), and the addition of fucose appears to have no effect on this affinity. These results indicate that the FVII EGF-1 alone cannot form a tight complex with TF and suggest that the high binding affinity of FVIIa for TF requires cooperative interaction among the four domains in FVII with TF. Although the fucose has no significant effect on the interaction between TF and the individual FVII EGF-1 domain, it may affect the interaction of full-length FVIIa with TF by influencing its Ca2+-binding affinity.

Incidentally detected renal tumors

Asymptomatic renal masses are increasingly being found during radiography ordered for other reasons. Unfortunately, radiography cannot always provide precise identification of the masses, some of which are renal cell carcinomas. Whether to choose surveillance, surgery, or other therapy depends on the tumor and on the patient.

Stereoselectivity of the Chinese hamster ovary cell sialidase: sialoside hydrolysis with overall retention of configuration

The stereochemical course of enzymatic hydrolysis by the soluble sialidase from Chinese hamster ovary cells, expressed as a recombinant protein in insect Sf9 cells, was determined using proton nuclear magnetic resonance spectroscopy. 4-Methyl umbelliferyl-N-acetyl neuraminic acid was employed as substrate, and the stereoselectivity of the enzyme catalysis was ascertained by monitoring the H3 axial and equatorial protons of the sialic acid product over the reaction course. At both high (3 U) and low concentrations (1 U) of the enzyme, the alpha anomer of the sialic acid was clearly observed as the initial reaction product. The corresponding beta anomer of sialic acid appeared much later in the reaction, arising from mutarotation of the alpha anomer. Similar studies were also carried out using the Salmonella typhimurium LT 2 sialidase, a protein of similar size and substrate specificity. Both enzymes apparently cleave the alpha linked sialoside substrate with retention of configuration. Based on the observations of a wide variety of other glycohydrolytic enzymes that have shown a strong correlation of the stereoselectivity of catalysis with active site topology (Gebler et al., J. Biol. Chem. 267, 12559-12561, 1992), the results obtained here suggest that the microbial and mammalian sialidases have a homologous active site architecture even though the molecules do not share significant primary sequence similarities.

The effect of diagnosis and treatment delay on prognostic factors and survival in endometrial carcinoma

OBJECTIVE

The aim of this study was to assess the association of diagnosis and treatment delay with established prognostic factors and survival.

STUDY DESIGN

The study group comprised 181 consecutive patients with endometrial carcinoma diagnosed between 1970 and 1986, whose records contained details with regard to diagnosis delay; 174 of them also contained details with regard to treatment delay.

RESULTS

The significant prognostic factors that we found, namely, age, clinical stage, grade, depth of myometrial invasion, and histologic type, are in line with those of other studies. However, no significant correlation was found between the duration of delay and these prognostic factors or with survival.

CONCLUSION

We conclude that delay of diagnosis (< 1 year) and of treatment of < 4 months do not compromise survival of patients with endometrial cancer.

Effect of diclofenac sodium (Voltaren) on hypoxia-induced corneal edema in humans

We evaluated the effect of diclofenac sodium (Voltaren) drops on patients with hypoxia-induced corneal edema. Thirty age- and sex-matched subjects were randomly assigned to one of three groups. Members of each group received masked solutions of either Voltaren, Voltaren vehicle, or a non-preserved lubricant (Cellufresh) every 6 hours for 24 hours and then hourly for 2 hours immediately prior to inducing corneal edema in the experimental eye. Bilateral ultrasonic pachymetry was performed prior to applying a thick contact lens and light patch on the experimental eye of all subjects for 3 hours. The fellow eye served as the control. Following lens removal, bilateral corneal thickness was measured every 30 minutes. The percentage change in corneal swelling for each subject and group was calculated. The findings were also normalized to the control eye to minimize diurnal and individual variability. The results were plotted both as percentage change from hour 0 and percentage change normalized to the control eye. Corneal swelling ranged from 9-11% in all 3 groups, with recovery at 2-3 hours. No significant difference was found among the three groups (P > 0.05, ANOVA). There was a slight trend toward reduced thickness in the Cellufresh group, but this was not statistically significant. Voltaren does not appear to have an effect on the hypoxia-induced corneal edema associated with the production of arachidonic acid pathway metabolites.

Interacting gray solitons

We present what is to our knowledge the first general theory for describing interacting well-separated gray spatial solitons, propagating in an arbitrary self-defocusing nonlinearity. It reveals why two dark solitons will in general repel, becoming less dark as they propagate. The results are illustrated with analytic expressions for the Kerr and the saturating nonlinearities.

Teaching high-resolution nuclear magnetic resonance to graduate students in biophysics

Teaching modern methods of high resolution, multi-dimensional nuclear magnetic resonance (NMR) spectroscopy in the limited time usually available is a challenge because of the breadth and complexity of the subject. Here we present two outlines for lectures on basic principles and biophysical applications of NMR, either in one lecture or in six to twelve lectures. We advocate emphasizing the versatility of NMR, and its numerous applications to biophysical questions. An annotated list of references is provided.

A detailed 1H and 13C NMR study of a repeating disaccharide of hyaluronan: the effects of temperature and counterion type

For the first time, a detailed NMR study of the conformation of methyl 2-acetamido-2-deoxy-3-O-(beta-D-glucopyranosyluronic acid)-beta-D-glucopyranoside (disaccharide 1) in aqueous solution is reported. This disaccharide is a repeating unit of hyaluronan, a polysaccharide with widespread biological and pharmaceutical applications. Relatively small changes in temperature, over typical experimental conditions (0-37 degrees C), completely change the appearance of its one-dimensional 1H NMR spectrum at 500 MHz. To determine the underlying cause for this temperature sensitivity, we analyzed 1H and 13C chemical shifts, temperature coefficients (delta gamma/delta T), 1H-1H coupling constants, and interglycosidic 1H-13C coupling constants for 1 as a function of temperature. For comparison, we measured the temperature dependence of 1H chemical shifts and coupling constants for related monosaccharides: glucuronate (GlcUA or U) and N-acetylglucosamine (GlcNAc or N), and glucose (Glc). The temperature sensitivity of the 1H spectrum of 1 is caused by relatively larger values of delta delta/delta T for some ring protons, rather than a conformational change. The effect is mediated by strong coupling. To detect the presence of long-lived intramolecular hydrogen bonds in the disaccharide, we measured chemical shifts, delta delta/delta T, and coupling constants for hydroxyl protons of 1, GlcUA, and GlcNAc in 1:1 H2O-acetone-d6 at low temperature. We compared 1H NMR parameters for 1, GlcUA, and GlcNAc in water with published values measured in Me2SO-d6 and concluded that interactions with water predominated. We found no evidence for long-lived intramolecular hydrogen bonds occurring in 1 in aqueous solution.

Antibodies to seven rotavirus serotypes in cord sera, maternal sera, and colostrum of German women

Forty percent of colostrum samples from German women showed neutralizing antibody titers of greater than or equal to 50 to rotavirus (RV) serotypes 1, 3, 4, and 6. Antibody to serotypes 2, 8, and 9 was less prevalent. Titers are, however, too low to indicate an important effect of colostrum on the RV vaccine take rate. On the other hand, about 50% of the cord serum samples showed high neutralizing-antibody titers to serotypes 1, 3, and 4, which could interfere with the take rate of RV vaccines based on these serotypes in very young infants.

Significant conformational changes in an antigenic carbohydrate epitope upon binding to a monoclonal antibody

Transferred nuclear Overhauser enhancement spectroscopy (TRNOE) was used to observe changes in a ligand's conformation upon binding to its specific antibody. The ligands studied were methyl O-beta-D-galactopyranosyl(1----6)-4-deoxy-4-fluoro-beta-D-galactopyra nos ide (me4FGal2) and its selectively deuteriated analogue, methyl O-beta-D-galactopyranosyl(1----6)-4-deoxy-2-deuterio-4-fluoro-beta -D- galactopyranoside (me4F2dGal2). The monoclonal antibody was mouse IgA X24. The solution conformation of the free ligand me4F2dGal2 was inferred from measurements of vicinal 1H-1H coupling constants, long-range 1H-13C coupling constants, and NOE cross-peak intensities. For free ligand, both galactosyl residues adopt a regular chair conformation, but the NMR spectra are incompatible with a single unique conformation of the glycosidic linkage. Analysis of 1H-1H and 1H-13C constants indicates that the major conformer has an extended conformation: phi = -120 degrees; psi = 180 degrees; and omega = 75 degrees. TRNOE measurements on me4FGal2 and me4F2dGal2 in the presence of the specific antibody indicate that the pyranose ring pucker of each galactose ring remains unchanged, but rotations about the glycosidic linkage occur upon binding to X24. Computer calculations indicate that there are two sets of torsion angles that satisfy the observed NMR constraints, namely, phi = -152 +/- 9 degrees; psi = -128 +/- 7 degrees; and omega = -158 +/- 6 degrees; and a conformer with phi = -53 +/- 6 degrees; psi = 154 +/- 10 degrees; and omega = -173 +/- 6 degrees. Neither conformation is similar to any of the observed conformations of the free disaccharide.(ABSTRACT TRUNCATED AT 250 WORDS)

Systematic chemical synthesis and n.m.r. spectra of methyl alpha-glycosides of isomalto-oligosaccharides and related compounds

Acid-catalyzed thiophenolysis of 1,6-anhydro-2,3,4-tri-O-benzyl-beta-D-glucopyranose and acetylation of the resulting phenyl 2,3,4-tri-O-benzyl-1-thio-alpha-D-glucopyranoside (4) gave phenyl 6-O-acetyl-2,3,4-tri-O-benzyl-1-thio-alpha-D-glucopyranoside (5). Reaction of 5 with chlorine gave, stereospecifically, the corresponding beta-glycosyl chloride, which was treated with 4 in the presence of silver perchlorate and 2,4,6-trimethylpyridine to afford phenyl O-(6-O-acetyl-2,3,4-tri-O-benzyl-alpha-D-glucopyranosyl)-(1----6)-2,3,4- tri-O- benzyl-1-thio-alpha-D-glucopyranoside (17). Crystalline O-(6-O-acetyl-2,3,4-tri-O-benzyl-alpha-D-glucopyranosyl)-(1----6)-2,3,4- tri- O-benzyl-beta-D-glucopyranosyl chloride, readily obtainable in a stereo-specific manner from 17 by treatment with chlorine, was used as the key glycosyl (isomaltosyl) donor in the blockwise synthesis of methyl glycosides of isomalto-oligosaccharides, up to and including the octasaccharide. The methyl alpha-glycoside of isomaltotetraose fluorinated at C-6 of the terminal D-glucopyranosyl group was prepared by using SnCl2-activated 2,3,4-tri-O-benzyl-6-deoxy-6-fluoro-alpha,beta-D-glucopyranosyl fluoride as the glycosyl donor, a suitably protected methyl alpha-isomaltotrioside as the nucleophile, and silver perchlorate as the promoter. The n.m.r. spectra (1H- and 13C-) of numerous synthetic intermediates were analyzed and completely assigned by a variety of two-dimensional homo- and hetero-nuclear n.m.r.-spectroscopic techniques, and the final deprotected title oligosaccharides were characterized by 13C-n.m.r. data. Silver perchlorate-mediated glycosylation reactions involving beta-glycosyl chlorides were high-yielding and showed high stereo-selectivity for the formation of an alpha-(cis)-glycosidic linkage. The practical limitation of obtaining high isomalto-oligosaccharides in this way appears to lie solely in the separation technique applied for the resolution of the crude products formed.

Seroconversion patterns to four human rotavirus serotypes in hospitalized infants with acute rotavirus gastroenteritis

We studied rotavirus-specific antibodies in paired sera from 71 hospitalized infants with acute rotavirus gastroenteritis. Most of the infants were less than six months old. Infants with serological evidence of a secondary rotavirus infection were excluded. With an enzyme-linked immunosorbent assay, 46% of the 71 infants studied showed specific IgM in convalescent sera. Titers of specific IgG and IgA increased in 7% and 2% of the infants, respectively. The presence of specific IgM correlated positively with age and severity of clinical symptoms. With a neutralization test, 59% of the infants showed a seroconversion: 20% to a single serotype (7% to serotype 1, 7% to serotype 3, and 6% to serotype 4), 21% seroconverted to two serotypes (nearly exclusively to serotypes 1 and 3), and 18% seroconverted to three serotypes (exclusively to serotypes 1, 3, and 4). No infant seroconverted to serotype 2 or to the heterologous (bovine) serotype 6.

Prevalence of antibodies to rotavirus in different age-groups of infants in Bochum, West Germany

We studied the prevalence of antibody to rotavirus in 386 serum samples obtained from different age-groups of infants in Bochum, West Germany. Cord sera mirrored the IgG titer and serotype specificity of the corresponding maternal sera. IgG antibody prevalence decreased with age, reached a minimum between four and 12 months, and increased thereafter. IgM antibodies appeared first in the eight- to 12-month age-group, and IgM prevalence remained high thereafter. The serum level of IgA was low in all age-groups. Significant prevalence increases with increasing age were observed for neutralizing antibodies to rotavirus serotypes 1 and 3. Antibodies to serotype 4 had not reached adult level at 2.5 y of age. Prevalence of antibodies to serotype 2 was low in all age-groups. The percentage of monospecific sera neutralizing only one serotype was high in young infants eight to 12 months of age and decreased significantly with increasing age.

Application of new, high-sensitivity, 1H-13C-n.m.r.-spectral techniques to the study of oligosaccharides

Four n.m.r. methods that are especially useful for characterization of oligosaccharides are applied to the trisaccharide alpha-Neu5Ac-(2----3)-beta-Gal-(1----4)-Glc (1). Three of these are two-dimensional, heteronuclear methods that provide chemical-shift correlation maps having much higher sensitivity than was previously possible, because they rely on indirect observation of 13C via 1H detection. These methods are used to assign, completely, the 1H- and 13C-n.m.r. spectra of both anomers of the trisaccharide. In addition to these two-dimensional methods, a one-dimensional method is used to measure 1H-1H coupling-constants accurately within each sugar ring. The values of the coupling constants thus measured for 1 are evidence that the conformations of the individual sugar rings are not affected by linkage into the trisaccharide.

Use of bovine milk concentrate containing antibody to rotavirus to treat rotavirus gastroenteritis in infants

The use of a concentrate containing milk immunoglobulins prepared from rotavirus-hyperimmunized cows (neutralization titer, 1:6,000 for a 10% solution) to treat infants hospitalized for acute rotavirus gastroenteritis resulted in a significant (P = .008) reduction in the duration of excretion of virus. Stool samples from treated infants showed the presence of bovine milk immunoglobulins in 47% of cases and of neutralizing activity in 43% (mean neutralization titer, 1:48); stool samples from control infants showed neutralizing activities in only 3% of cases (neutralization titers, less than 1:20). Immunoelectrophoresis of stool extracts revealed fragment A, a bovine analogue of F(ab')2 or Fab, as the major product of in vitro and in vivo digestion of the immunoglobulins. Cessation of excretion of virus correlated with the appearance of neutralizing activities in 19 of 25 infants. Only concentrate-treated infants with high neutralizing activity in stools showed a statistically significant reduction in duration of excretion of virus; this duration in concentrate-treated infants with low neutralizing activity was comparable with controls.

A multinuclear NMR study of the interactions of cations with proteoglycans, heparin, and Ficoll

Measurements of NMR relaxation rates of 23Na, 39K, 25Mg and 43Ca were used to evaluate the extent of cation binding in solution to bovine nasal cartilage proteoglycans, hog mucosal heparin, and Ficoll (Pharmacia). The two most important factors determining relaxation rates in the presence of the polymers examined were polymer concentration and charge density. We found that proteoglycans did not bind monovalent cations but did bind divalent cations to a relatively small extent. Heparin bound monovalent and divalent cations to a much greater extent. Assembly of glycosaminoglycan chains into proteoglycan aggregates had no effect on the extent of cation binding.

Two-dimensional nuclear magnetic resonance spectroscopy

Great spectral simplification can be obtained by spreading the conventional one-dimensional nuclear magnetic resonance (NMR) spectrum in two independent frequency dimensions. This so-called two-dimensional NMR spectroscopy removes spectral overlap, facilitates spectral assignment, and provides a wealth of additional information. For example, conformational information related to interproton distances is available from resonance intensities in certain types of two-dimensional experiments. Another method generates 1H NMR spectra of a preselected fragment of the molecule, suppressing resonances from other regions and greatly simplifying spectral appearance. Two-dimensional NMR spectroscopy can also be applied to the study of 13C and 15N, not only providing valuable connectivity information but also improving sensitivity of 13C and 15N detection by up to two orders of magnitude.

Surgical treatment of dislocated iris-plane intraocular lenses

This report describes a patient with a Binkhorst four-loop intraocular lens dislocated in the vitreous. The implant was repositioned by means of a combination of the Barraquer-Chowdhury needle-fixation method with a McCannel suture. The pupil was maximally dilated, and the patient was placed in the prone position. When the implant drifted into the anterior chamber, it was anchored with a 25-gauge spinal needle through the limbus. It was then refixated to the iris with a 10-0 prolene suture.

Bulimia in men: report of three cases with neuroendocrine findings

Bulimia, like anorexia nervosa, primarily affects women. Although survey reports have shown that as many as 10%-13% of students meeting DSM-III criteria for bulimia are male, 1,2 detailed clinical descriptions of male bulimic patients are rare. The following case reports describe three men seen for evaluation of bulimia at the UCLA Eating Disorders Clinic.