Alginate oligosaccharides modify hyphal infiltration of Candida albicans in an in vitro model of invasive human candidosis.

AIMS: A novel alginate oligomer (OligoG CF-5/20) has been shown to potentiate antifungal therapy against a range of fungal pathogens. The current study assessed the effect of this oligomer on in vitro virulence factor expression and epithelial invasion by Candida species. METHODS AND RESULTS: Plate substrate assays and epithelial models were used to assess Candida albicans (CCUG 39343 and ATCC 90028) invasion, in conjunction with confocal laser scanning microscopy and histochemistry. Expression of candidal virulence factors was determined biochemically and by quantitative PCR (qPCR). Changes in surface charge of C. albicans following OligoG treatment were analysed using electrophoretic light scattering. OligoG induced marked alterations in hyphal formation in the substrate assays and reduced invasion in the epithelial model (P < 0·001). Significant dose-dependent inhibition of phospholipase activity in C. albicans was evident following OligoG treatment (P < 0·05). While OligoG binding failed to affect alterations in surface charge (P > 0·05), qPCR demonstrated a reduction in phospholipase B (PLB2) and SAPs (SAP4 and SAP6) expression. CONCLUSION: OligoG CF-5/20 reduced in vitro virulence factor expression and invasion by C. albicans. SIGNIFICANCE AND IMPACT OF THE STUDY: These results, and the previously described potentiation of antifungal activity, define a potential therapeutic opportunity in the treatment of invasive candidal infections.

Late Holocene extinction of Puerto Rican native land mammals.

West Indian land mammals have suffered the most severe extinctions of any Holocene mammal faunas. However, 'last-occurrence' dates based on radiometric or robust stratigraphic data remain unavailable for most West Indian species, making it impossible to identify factors responsible for these extinctions. Here, we present new radiometric dates from archaeological and palaeontological sites on Puerto Rico, the only Greater Antillean island to have lost all native land mammals. Although it has been suggested that these species died out earlier than other West Indian mammals, we demonstrate that Puerto Rican mammal last-occurrence dates are in close agreement with those from other Antillean islands, as several species in fact persisted for millennia following Amerindian arrival. Echimyid rodents and nesophontid 'island-shrews' were still present on Puerto Rico approximately 1000 years BP, and probably became extinct following European arrival. The large (13kg) heptaxodontid rodent Elasmodontomys obliquus also appears to have survived for over 2000 years after Amerindian colonization, suggesting that at least some large West Indian mammals became extinct in protracted pre-European 'sitzkrieg'-style events rather than 'blitzkrieg'-style overkill.

The relationship between changes in daily air pollution and hospitalizations in Perth, Australia 1992-1998: a case-crossover study.

A case-crossover study was undertaken to investigate the relationship between daily air pollutant concentrations and daily hospitalizations for selected disease categories in Perth, Western Australia. Daily measurements of particles (measured by nephelometry and PM2.5), photochemical oxidants (measured as ozone), nitrogen dioxide (NO2) and carbon monoxide (CO) concentrations were obtained from 1992 to 1998 via a metropolitan network of monitoring stations. Daily PM2.5 concentrations were estimated using monitored data, modelling and interpolation. Hospital morbidity data for respiratory, cardiovascular (CVD), gastrointestinal (GI) diseases, chronic obstructive pulmonary diseases (COPD) excluding asthma; pneumonia/influenza diseases; and asthma were obtained and categorized into all ages, less than 15 years and greater than 65 years. Gastrointestinal morbidity was used as a control disease. The data were analyzed using conditional logistic regression. The results showed a small number of significant associations for daily changes in particle concentrations, nitrogen dioxide and carbon monoxide for the respiratory diseases, CODP, pneumonia, asthma and CVD hospitalizations. Changes in ozone concentrations were not significantly associated with any disease outcomes. These data provide useful information on the potential health impacts of air pollution in an airshed with very low sulphur dioxide concentrations and lower nitrogen dioxide concentrations commonly found in many other cities.

Differential susceptibility of transferrin glycoforms to chymotrypsin: a proteomics approach to the detection of carbohydrate-deficient transferrin.

Transferrin exhibits heterogeneity in glycosylation characteristic of pathological changes in alcohol abuse and congenital disorders in glycosylation. This study investigated an alternative approach in the detection of carbohydrate-deficient transferrin based on the premise that glycosylation may afford some degree of protection to proteolytic action. Differential susceptibility to proteolysis by chymotrypsin was demonstrated for normal glycosylated and nonglycosylated recombinant human transferrin, using reverse-phase (RP) HPLC, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and LC-tandem mass spectrometry (MS/MS). Peptide fragmentation profiles were consistent with a predominantly high-specificity cleavage pattern of chymotrypsin. The observed peptide fragmentation profile showed that the C-lobe of recombinant full-length nonglycosylated transferrin (rhTf-NG) appeared to be preferentially cleaved, while cleavage of the N-lobe was restricted to the N-terminal and link sequence regions. Although chymotryptic cleavage sites abound in the N-lobe, their resistance to cleavage was independent of glycosylation. Compared to previous studies of lactoferrin, our data suggest disparity in the role by which glycosylation exerts a protective effect in the siderophilin family. It was clear from the transferrin digestions analyzed by HPLC that N-linked glycosylation did confer protection from proteolysis by chymotrypsin. After fragmentation, a range of peptides representing previously cryptic epitopes were identified as potential candidates for an immunological approach to differentiate between the different transferrin glycoforms. Based on its proximity to the Asn413 glycosylation site, a 15-mer peptide, m/z 1690.472 (NKSDNCEDTPEAGYF), was identified as a suitable candidate for raising anti-peptide antibodies for subsequent immunological detection. This novel approach could form the basis for an alternative assay or reference method for the detection of carbohydrate-deficient transferrin.

The effect of age on the relationship between birth order and immunoglobulin E sensitization.

BACKGROUND: An association between birth order and IgE sensitization or allergic diseases has been reported in many studies. OBJECTIVE: To assess the effect of age on the relationship between reduced IgE sensitization and increased birth order and to test the hypothesis that this would decline with increasing age. METHODS: As part of a birth cohort study, IgE sensitization to common allergens was determined by skin prick testing at ages 6 and 12 months, 6 and 11 years. RESULTS: The original cohort numbered 253 individuals of whom 96 (38%) were first born. Compared with individuals with older siblings, first-born individuals had increased IgE sensitization at 6 (odds ratio (OR) 2.4 [95% confidence interval (CI) 1.0, 6.3], P=0.05, n=197) and 12 months of age (OR 6.7 [1.7, 25.0] P=0.002, n=172) and at 6 years of age (OR 2.3 [1.0, 5.6] P=0.05, n=113) but not at 11 years of age (OR 1.2, P>0.4, n=182). When age at onset of IgE sensitization was considered (n=61), 16 had infant onset IgE sensitization (nine were first born), 24 had early childhood onset IgE sensitization (nine first born) and 21 had late childhood onset IgE sensitization (two first born), P=0.0016. Further analysis revealed a similar pattern for children with older brothers (P=0.0097) but not older sisters (P=0.5). CONCLUSIONS: These findings indicated that having an older brother delays the onset of IgE sensitization but may not prevent IgE sensitization per se. The apparent protective effect of older siblings on allergic diseases reported elsewhere might involve delaying the onset of IgE sensitization.

Determinants of airway responsiveness to histamine in children.

Increased airway responsiveness (AR) is associated with asthma, but not all individuals with increased AR have asthma. The aim of this study was to identify factors, other than physician-diagnosed asthma (PDA), which are associated with increased AR. In a longitudinal study, data were collected on atopy and lower respiratory tract illness (LRTI) in infancy, and AR (expressed as dose-response slope (DRS)), atopy, tobacco-smoke exposure and PDA in childhood. At age 6 yrs, DRS was assessed in 102 children, of whom 22 (22%) had PDA; the corresponding figures at 11 yrs of age were 176 and 29 (15%). At age 6 yrs, DRS was significantly associated with PDA, current atopy and parental smoking (n = 83). At age 11 yrs, DRS was significantly associated with PDA, current atopy and LRTI in the first six months (n = 75). There was a significant positive interaction between atopy at age 12 months and PDA age 11 yrs. In conclusion, these data suggest that factors other than asthma or atopy may determine the level of airway responsiveness in children. In children with asthma, airway responsiveness may be influenced by the early onset of atopy. The current findings may explain the inconsistent relationship between airway responsiveness and asthma.

Enhanced diffraction from a grating on the surface of a negative-index metamaterial.

We show by numerical simulation as well as by measurements on negative-index metamaterial wedge samples, that the unavoidable stepping of the refraction interface-due to the finite unit-cell size inherent to metamaterials-can give rise to a well-defined diffracted beam in addition to the negatively refracted beam. The direction of the diffracted beam is consistent with elementary diffraction theory; however, the coupling to this higher order beam is much larger than would be the case for a positive index material. The results confirm recent theoretical predictions of enhanced diffraction for negative-index grating surfaces.

beta2 adrenoceptor Arg16Gly polymorphism, airway responsiveness, lung function and asthma in infants and children.

BACKGROUND: We have previously reported a relationship between increased airway responsiveness (AR) in infancy and reduced childhood lung function. OBJECTIVE: The current study aimed to determine whether the Arg16Gly polymorphism of the beta2 adrenoceptor (beta2AR) gene was important to this relationship. METHODS: A cohort that initially numbered 253 individuals underwent assessments of AR and lung function aged 1 month, 6 and 11 years; genotyping for polymorphisms of the beta(2)AR was performed. RESULTS: At 1 month of age, the genotype homozygous Arg16 (n=24) was associated with a mean increase in log dose-response slope (AR) of 0.27 [95% confidence interval (CI) 0.07, 0.49] compared with the genotype homozygous Gly16 (n=58), P=0.01. At 11 years of age, the genotype homozygous Arg16 (n=35) was associated with a mean reduction in the percentage of forced expiratory volume in 1 s of 5.3% [95% CI 0.3, 10.2] compared with the genotype homozygous Gly16 (n=65), P=0.03. There was no association between the Arg16Gly polymorphism and atopy or diagnosed asthma. However, nine of 69 individuals with the genotype homozygous Gly16 were admitted to hospital with asthma compared with five out of 111 individuals with the remaining genotypes (P<0.05). CONCLUSION: The Arg16Gly polymorphism may be important to the association between increased AR in infancy and reduced lung function in childhood and may also be a determinant of asthma severity in children but not asthma per se.

Design, synthesis, and evaluation of estradiol-linked genotoxicants as anti-cancer agents.

A series of bifunctional compounds was prepared consisting of 17beta estradiol linked to a DNA damaging N,N-bis-(2-chloroethyl)aniline. The objective of our studies was to determine the characteristics of the linker that permitted both reaction with DNA and binding of the resultant covalent adducts to the estrogen receptor. Linker characteristics were pivotal determinants underlying the ability of the compounds to kill selectively breast cancer cells that express the estrogen receptor.

Interfering with cancer: a brief outline of advances in RNA interference in oncology.

RNA interference (RNAi) is a potent and ubiquitous gene-silencing mechanism that is generating considerable excitement in the fields of molecular biology and gene therapy. It is now in widespread use for loss-of-function analysis in many diseases including cancer. Nevertheless, RNAi is still in its infancy, with new discoveries appearing on a monthly basis. This article presents a brief outline of the history and recent advances in RNAi with a specific focus on its potential in oncology.

Tumor marker workshops.

Since 1996, the nine ISOBM Workshops have so far characterized more than 300 monoclonal antibodies to a variety of tumor markers that include CA125, AFP, PSA, MUC1, Cytokeratins, Sialyl Le(a), hCG, CEA, ALP, and more recently SCC, and S100. Besides the basic characterization of antibodies and their epitope configurations, several workshops have also addressed specific problems associated with multiple antigen variants. These workshops have been able to make significant advances well beyond those possible through any normal collaboration study. The data and impact of these workshops with their summary reports are reviewed.

New immunoassays for MUC1 in breast cancer.

Eleven experimental immunofluorometric assays (IFMAs) were made using antibodies previously tested for epitope specificities. These assays were compared with six commercially available immunoassays. The clinical performance of these experimental assays was evaluated by analysing sera from 138 breast cancer patients and 105 female blood donors. The clinical performance of these assays was evaluated at a set specificity of 0.94. The highest overall sensitivity (0.56) was observed in the experimental assay with the antibody BC2 as solid phase and GP1.4 as the tracer antibody. This combination also showed the highest sensitivity in stage I/II breast cancer. The Truquant assay (Biomira) had an overall sensitivity of 0.51, and the highest sensitivity in stages III and IV at 0.65 and 0.94, respectively. The remaining commercial assays, with sensitivity ranging from 0.67 to 0.79, were below the top five experimental assays that showed sensitivity values between 0.79 and 0.85. The findings from our current study suggest that further development in MUC1 immunoassays could improve the detection of relapse in breast cancer patients.

MUC1: antibodies and immunoassays.

High molecular weight mucins represent a unique challenge as tumor markers by virtue of their complex array of epitopes. The list is dominated by the high molecular weight mucins MUC1, CEA and CA125. While the currently accepted role for these tumor markers is in the prediction and detection of relapse, it is possible that their sensitivity and specificity can be improved. Although immunoassays detecting the tumor marker MUC1 are both sensitive and specific for predicting relapse in breast cancer, so far they are not in widespread use in the follow-up of this disease. Are there new combinations of conventional reagents that could improve assay sensitivity, or should we be looking for more radical changes in assay design incorporating combinatorial technology?

Immunomagnetic DNA aptamer assay.

DNA aptamers, oligonucleotides with antibody-like binding properties, are easy to manufacture and modify. As a class of molecules, they represent the biggest revolution to immunodiagnostics since the discovery of monoclonal antibodies. To demonstrate that DNA aptamers are versatile reagents for use as in vitro diagnostic tools, we developed a hybrid immunobead assay based on a 5'-biotinylated DNA thrombin aptamer (5'-GGTTGGTGTGGTTGG-3') and an anti-thrombin antibody (EST-7). Our results show that the thrombin DNA aptamer is capable of binding to its target molecule under stringent in vitro assay conditions and at physiological concentrations. These findings also support the view that DNA aptamers have potential value as complementary reagents in diagnostic assays.

Airway responsiveness in early infancy predicts asthma, lung function, and respiratory symptoms by school age.

Asthma is the most common chronic childhood disease in developed nations. Little is known about the relationship between airway responsiveness in infancy and the development of asthma later in life. The relationship of airway responsiveness at 1 mo with asthma, atopy, lower respiratory symptoms, and lung function at 6 yr of age was investigated prospectively in 95 white children from a randomly ascertained birth cohort. Baseline spirometry, airway responsiveness to histamine, and skin reactivity to common allergens were assessed at the age of 1 mo and 6 yr. Total serum immunoglobulin E (IgE) was measured from cord blood and at 6 yr. Blood eosinophil counts were measured at 6 yr only. Family, symptom, and exposure histories at both time points were derived from questionnaire data. Independently of the other factors assessed, increased airway responsiveness at 1 mo was significantly associated with the following parameters measured at six yr: decreased FEV(1) (p < 0.001); decreased FVC (p < 0.001); physician-diagnosed asthma (p < 0.001); and lower respiratory tract symptoms (p < 0.05). None of the other physiologic factors measured in infancy showed such consistent associations with important clinical and physiologic outcomes at age 6. These data suggest that airway responsiveness in early life defines a functional state that is associated with abnormal airway function, lower respiratory symptoms, and the emergence of asthma by 6 yr of age.

Relationship of follicle numbers and estradiol levels to multiple implantation in 3,608 intrauterine insemination cycles.

OBJECTIVE: To determine the relationship of follicle numbers and estradiol (E(2)) levels to multiple implantations in human menopausal gonadotropin (hMG) and clomiphene citrate (CC) cycles. DESIGN: Fifteen-year prospective study. SETTING: Private infertility clinic. PATIENT(S): Women who underwent 3608 cycles of husband or donor intrauterine insemination (IUI). INTERVENTION(S): Ovulation induction (OI) with CC, hMG, or CC+hMG. MAIN OUTCOME MEASURE(S): Pregnancy and multiple implantations. RESULT(S): Triplet and higher-order implantations-but not twin implantations-were related to age, E(2) levels, and number of follicles > or = 12 mm and > or = 15 mm, but not number of follicles > or = 18 mm, in hMG and CC+hMG cycles. For patients less than 35 years old, three or more implantations tripled when six or more follicles were > or = 12 mm, in CC, hMG, and CC+hMG cycles, and when E(2) was > or = 1000 pg mL in hMG and CC+hMG cycles. For patients 35 or older, pregnancy rates in hMG and CC+hMG cycles doubled when six or more follicles were > or = 12 mm, or E(2) levels were >1000 pg mL, whereas 3 or more implantations were not significantly increased. CONCLUSIONS: Withholding hCG or IUI in CC, hMG, and CC+hMG cycles when six or more follicles are > or = 12 mm may reduce triplet and higher-order implantations by 67% without significantly reducing pregnancy rates for patients under 35 years of age.

CA 125: the end of the beginning.

CA 125, a high-molecular-weight mucin, was first defined in 1981 by the monoclonal antibody OC125. Until recently, it has defied many attempts to purify it from a variety of sources, although many research groups have successfully raised antibodies that bind to CA 125. Nevertheless, CA 125 has demonstrated its considerable value as a marker in monitoring patients with ovarian cancer. This year, two research groups have succeeded in cloning the high-molecular-weight mucin CA 125. Their findings are summarized and the significance discussed in light of existing data from the human genome.