Performance of Orbicella faveolata larval cohorts does not align with previously observed thermal tolerance of adult source populations

Orbicella faveolata, commonly known as the mountainous star coral, is a dominant reef-building species in the Caribbean, but populations have suffered sharp declines since the 1980s due to repeated bleaching and disease-driven mortality. Prior research has shown that inshore adult O. faveolata populations in the Florida Keys are able to maintain high coral cover and recover from bleaching faster than their offshore counterparts. However, whether this origin-specific variation in thermal resistance is heritable remains unclear. To address this knowledge gap, we produced purebred and hybrid larval crosses from O. faveolata gametes collected at two distinct reefs in the Upper Florida Keys, a nearshore site (Cheeca Rocks, CR) and an offshore site (Horseshoe Reef, HR), in two different years (2019, 2021). We then subjected these aposymbiotic larvae to severe (36°C) and moderate (32°C) heat challenges to quantify their thermal tolerance. Contrary to our expectation based on patterns of adult thermal tolerance, HR purebred larvae survived better and exhibited gene expression profiles that were less driven by stress response under elevated temperature compared to purebred CR and hybrid larvae. One potential explanation could be the compromised reproductive output of CR adult colonies due to repeated summer bleaching events in 2018 and 2019, as gametes originating from CR in 2019 contained less storage lipids than those from HR. These findings provide an important counter-example to the current selective breeding paradigm, that more tolerant parents will yield more tolerant offspring, and highlight the importance of adopting a holistic approach when evaluating larval quality for conservation and restoration purposes.

Opportunistic consumption of coral spawn by the ruby brittle star (Ophioderma rubicundum)

Many reef invertebrates reproduce through simultaneous broadcast spawning, with an apparent advantage of overwhelming potential predators and maximizing propagule survival. Although reef fish have been observed to consume coral gamete bundles during spawning events, there are few records of such predation by benthic invertebrates. Here, we document several instances of the ruby brittle star, Ophioderma rubicundum, capturing and consuming egg-sperm bundles of the mountainous star coral, Orbicella faveolata, and the symmetrical brain coral, Pseudodiploria strigosa, during spawning events in the Cayman Islands in 2012 and the Florida Keys in 2022. These observations are widely separated in space and time (>600 km, 10 years), suggesting that this behavior may be prevalent on western Atlantic reefs. Since O. rubicundum spawns on the same or subsequent nights as these coral species, we hypothesize that this opportunistic feeding behavior takes advantage of lipid-rich coral gamete bundles to recover energy reserves expended by the brittle star during gametogenesis. The consumption of coral gametes by adult brittle stars suggests an underexplored trophic link between reef invertebrates and also provides evidence that ophiuroid-coral symbioses may oscillate between commensalism and parasitism depending on the ontogeny and reproductive status of both animals. Our observations provide insights into the nuanced, dynamic associations between coral reef invertebrates and may have implications for coral reproductive success and resilience.

Larval longevity and competency patterns of Caribbean reef-building corals

The potential for long-distance larval dispersal depends on the longevity of planktonic, free-swimming larvae and their capacity to successfully recruit to reef habitat. We present multi-year laboratory observations of the persistence of planular larvae and settlement competency over time for cohorts derived from the same parental populations of the most important Caribbean reef building coral species, Orbicella faveolata and Acropora spp. Despite variability among years/cohorts, larvae of both species display capacity for extended longevity (up to 83 d) and competency (demonstrated at up to 48 d). Both species also displayed significantly reduced survivorship and lower realized settlement under elevated temperatures. Although the observed levels of settlement in 24 h competency assays was extremely variable, the timing of onset of competence were highly consistent among years/cohorts but distinct between species. Orbicella faveolata displayed onset of competence during day 3–5 or 4–7 (with or without exposure to positive settlement cue) after spawning; whereas, onset for Acropora spp. was day 7–8 or day 10–11 (with or without cue, respectively). This longer pre-competency period for Acropora spp. nonetheless corresponded to a greater persistence of A. palmata larvae to this age of competence (71–83% of initial cohort compared to 54–55% for O. faveolata). Such life history variation implies meaningful differences in likely dispersal potential between these imperiled reef-building species.

Microbiome differences in disease-resistant vs. susceptible Acropora corals subjected to disease challenge assays

In recent decades coral gardening has become increasingly popular to restore degraded reef ecosystems. However, the growth and survivorship of nursery-reared outplanted corals are highly variable. Scientists are trying to identify genotypes that show signs of disease resistance and leverage these genotypes in restoring more resilient populations. In a previous study, a field disease grafting assay was conducted on nursery-reared Acropora cervicornis and Acropora palmata to quantify relative disease susceptibility. In this study, we further evaluate this field assay by investigating putative disease-causing agents and the microbiome of corals with disease-resistant phenotypes. We conducted 16S rRNA gene high-throughput sequencing on A. cervicornis and A. palmata that were grafted (inoculated) with a diseased A. cervicornis fragment. We found that independent of health state, A. cervicornis and A. palmata had distinct alpha and beta diversity patterns from one another and distinct dominant bacteria. In addition, despite different microbiome patterns between both inoculated coral species, the genus Sphingomonadaceae was significantly found in both diseased coral species. Additionally, a core bacteria member from the order Myxococcales was found at relatively higher abundances in corals with lower rates of disease development following grafting. In all, we identified Sphingomonadaceae as a putative coral pathogen and a bacterium from the order Myxococcales associated with corals that showed disease resistant phenotypes.

What drives phenotypic divergence among coral clonemates of Acropora palmata?

Evolutionary rescue of populations depends on their ability to produce phenotypic variation that is heritable and adaptive. DNA mutations are the best understood mechanisms to create phenotypic variation, but other, less well-studied mechanisms exist. Marine benthic foundation species provide opportunities to study these mechanisms because many are dominated by isogenic stands produced through asexual reproduction. For example, Caribbean acroporid corals are long lived and reproduce asexually via breakage of branches. Fragmentation is often the dominant mode of local population maintenance. Thus, large genets with many ramets (colonies) are common. Here, we observed phenotypic variation in stress responses within genets following the coral bleaching events in 2014 and 2015 caused by high water temperatures. This was not due to genetic variation in their symbiotic dinoflagellates (Symbiodinium "fitti") because each genet of this coral species typically harbours a single strain of S. "fitti". Characterization of the microbiome via 16S tag sequencing correlated the abundance of only two microbiome members (Tepidiphilus, Endozoicomonas) with a bleaching response. Epigenetic changes were significantly correlated with the host's genetic background, the location of the sampled polyps within the colonies (e.g., branch vs. base of colony), and differences in the colonies' condition during the bleaching event. We conclude that long-term microenvironmental differences led to changes in the way the ramets methylated their genomes, contributing to the differential bleaching response. However, most of the variation in differential bleaching response among clonemates of Acropora palmata remains unexplained. This research provides novel data and hypotheses to help understand intragenet variability in stress phenotypes of sessile marine species.

Genotypic variation in disease susceptibility among cultured stocks of elkhorn and staghorn corals

Disease mortality has been a primary driver of population declines and the threatened status of the foundational Caribbean corals, Acropora palmata and A. cervicornis. There remain few tools to effectively manage coral disease. Substantial investment is flowing into in situ culture and population enhancement efforts, while disease takes a variable but sometimes high toll in restored populations. If genetic resistance to disease can be identified in these corals, it may be leveraged to improve resistance in restored populations and possibly lead to effective diagnostic tests and disease treatments. Using a standardized field protocol based on replicated direct-graft challenge assays, we quantified this important trait in cultured stocks from three field nurseries in the Florida Keys. Field tests of 12 genotypes of A. palmata and 31 genotypes of A. cervicornis revealed significant genotypic variation in disease susceptibility of both species measured both as risk of transmission (percent of exposed fragments that displayed tissue loss) and as the rate of tissue loss (cm² d^–1) in fragments with elicited lesions. These assay results provide a measure of relative disease resistance that can be incorporated, along with consideration of other important traits such as growth and reproductive success, into restoration strategies to yield more resilient populations.

Development of a microscale land use regression model for predicting NO2 concentrations at a heavy trafficked suburban area in Auckland, NZ

Land use regression (LUR) analysis has become a key method to explain air pollutant concentrations at unmeasured sites at city or country scales, but little is known about the applicability of LUR at microscales. We present a microscale LUR model developed for a heavy trafficked section of road in Auckland, New Zealand. We also test the within-city transferability of LUR models developed at different spatial scales (local scale and city scale). Nitrogen dioxide (NO₂) was measured during summer at 40 sites and a LUR model was developed based on standard criteria. The results showed that LUR models are able to capture the microscale variability with the model explaining 66% of the variability in NO₂ concentrations. Predictor variables identified at this scale were street width, distance to major road, presence of awnings and number of bus stops, with the latter three also being important determinants at the local scale. This highlights the importance of street and building configurations for individual exposure at the street level. However, within-city transferability was limited with the number of bus stops being the only significant predictor variable at all spatial scales and locations tested, indicating the strong influence of diesel emissions related to bus traffic. These findings show that air quality monitoring is necessary at a high spatial density within cities in capturing small-scale variability in NO₂ concentrations at the street level and assessing individual exposure to traffic related air pollutants.

Thermal stress exposure, bleaching response, and mortality in the threatened coral Acropora palmata

Demographic data for Elkhorn coral, Acropora palmata, and in situ water temperature data from seven upper Florida Keys (USA) reefs revealed three warm thermal stress events between 2010 and 2016. During a mild bleaching event in 2011, up to 59% of colonies bleached, but no mortality resulted. In both 2014 and 2015, severe and unprecedented bleaching was observed with up to 100% of colonies bleached. A. palmata live tissue cover declined by one-third following the 2014-2015 events. Colony mortality of mildly- and non-bleached colonies did not differ but increased significantly with more severe bleaching. Increased bleaching prevalence corresponded to maximum daily average water temperatures above 31.3°C. However, the cumulative days with daily average exceeding 31.0°C provided a better predictor of bleaching response. The bleaching response of surviving colonies in 2015 was not consistent with acclimatization as most individual colonies bleached at least as badly as in 2014.

Use of a dense monitoring network of low-cost instruments to observe local changes in the diurnal ozone cycles as marine air passes over a geographically isolated urban centre

Ozone (O₃) concentrations in urban areas are spatially and temporally variable, influenced by chemical production, depletion through deposition and chemical titration processes and dispersion. To date, analysis of intra-urban variability of O₃ concentrations, and the influence of local controls on production and depletion rates, has been limited due to the low spatial and/or temporal resolution of measurements. We demonstrate that measurements made using a carefully managed multi-sensor network of low-cost gas-sensitive semiconductor instruments are sufficiently precise to resolve subtle but significant variations in ozone concentration across a region. Ozone was measured at 12 sites in the isolated subtropical city of Auckland, New Zealand. Overall O₃ concentrations in the Auckland region were low (annual mean: 19ppb) across all seasons, with a minimum in summer. Higher O₃ concentrations (max. 57ppb) were observed when wind speeds were >5ms^-1 and from the W/SW, and were associated with maritime air masses. Ozone formation in the Auckland region is low, which is attributed to a combination of the low O₃ background concentrations, the negligible contribution of long-range transport and the effect of NOx titration. Intra-urban variability showed that the lowest O₃ concentrations were measured at the residential sites, particularly at night and during rush hours. Ozone depletion from reaction with traffic-generated NO explains the rush-hour minima but did not fully account for the low night-time values. The results suggest that night-time depletion may result from other processes such as the reaction of ozone with nitrite on surfaces such as concrete, pointing towards the need for further studies concerning the rate and mechanism of dry deposition at night in urban areas.

Reef-scale trends in Florida Acropora spp. abundance and the effects of population enhancement

Since the listing of Acropora palmata and A. cervicornis under the US Endangered Species Act in 2006, increasing investments have been made in propagation of listed corals (primarily A. cervicornis, A. palmata to a much lesser extent) in offshore coral nurseries and outplanting cultured fragments to reef habitats. This investment is superimposed over a spatiotemporal patchwork of ongoing disturbances (especially storms, thermal bleaching, and disease) as well as the potential for natural population recovery. In 2014 and 2015, we repeated broad scale (>50 ha), low precision Acropora spp. censuses (i.e., direct observation by snorkelers documented via handheld GPS) originally conducted in appropriate reef habitats during 2005–2007 to evaluate the trajectory of local populations and the effect of population enhancement. Over the decade-long study, A. palmata showed a cumulative proportional decline of 0.4 –0.7x in colony density across all sites, despite very low levels of outplanting at some sites. A. cervicornis showed similar proportional declines at sites without outplanting. In contrast, sites that received A. cervicornis outplants showed a dramatic increase in density (over 13x). Indeed, change in A. cervicornis colony density was significantly positively correlated with cumulative numbers of outplants across sites. This study documents a substantive reef-scale benefit of Acropora spp. population enhancement in the Florida Keys, when performed at adequate levels, against a backdrop of ongoing population decline.

Raman spectroscopy as an effective screening method for detecting adulteration of milk with small nitrogen-rich molecules and sucrose

Adulteration of milk for commercial gain is acknowledged as a serious issue facing the dairy industry. Several analytical techniques can be used to detect adulteration but they often require time-consuming sample preparation, expensive laboratory equipment, and highly skilled personnel. Here we show that Raman spectroscopy provides a simple, selective, and sensitive method for screening milk, specifically for small nitrogen-rich compounds, such as melamine, urea, ammonium sulfate, dicyandiamide, and for sucrose. Univariate and multivariate statistical methods were used to determine limits of detection and quantification from Raman spectra of milk spiked with 50 to 1,000 mg/L of the N-rich compounds and 0.25 to 4% sucrose. Partial least squares (PLS) calibration provided limit of detection minimum thresholds <200mg/L (0.02%) for the 4 N-rich compounds and <0.8% for sucrose, without the need for surface-enhanced Raman spectroscopy. The results show high reproducibility (7% residual standard deviation) and 100% efficiency for screening of milk for these adulterants.

Decadal comparison of a diminishing coral community: a study using demographics to advance inferences of community status

The most common coral monitoring methods estimate coral abundance as percent cover, either via in situ observations or derived from images. In recent years, growing interest and effort has focused on colony-based (demographic) data to assess the status of coral populations and communities. In this study, we relied on two separate data sets (photo-derived percent cover estimates, 2002–12, and opportunistic in situ demographic sampling, 2004 and 2012) to more fully infer decadal changes in coral communities at a small, uninhabited Caribbean island. Photo-derived percent cover documented drastic declines in coral abundance including disproportionate declines in Orbicella spp. While overall in situ estimates of total coral density were not different between years, densities of several rarer taxa were. Meandrina meandrites and Stephanocoenia intersepta increased while Leptoseris cucullata decreased significantly, changes that were not discernable from the photo-derived cover estimates. Demographic data also showed significant shifts to larger colony sizes (both increased mean colony sizes and increased negative skewness of size frequency distributions, but similar maximum colony sizes) for most taxa likely indicating reduced recruitment. Orbicella spp. differed from this general pattern, significantly shifting to smaller colony sizes due to partial mortality. Both approaches detected significant decadal changes in coral community structure at Navassa, though the demographic sampling provided better resolution of more subtle, taxon-specific changes.

Environmental conditions influence tissue regeneration rates in scleractinian corals

Natural and anthropogenic factors may influence corals' ability to recover from partial mortality. To examine how environmental conditions affect lesion healing, we assessed several water quality parameters and tissue regeneration rates in corals at six reefs around St. Thomas, US Virgin Islands. We hypothesized that sites closer to developed areas would have poor water quality due to proximity to anthropogenic stresses, which would impede tissue regeneration. We found that water flow and turbidity most strongly influenced lesion recovery rates. The most impacted site, with high turbidity and low flow, recovered almost three times slower than the least impacted site, with low turbidity, high flow, and low levels of anthropogenic disturbance. Our results illustrate that in addition to lesion-specific factors known to affect tissue regeneration, environmental conditions can also control corals' healing rates. Resource managers can use this information to protect low-flow, turbid nearshore reefs by minimizing sources of anthropogenic stress.

Removal of corallivorous snails as a proactive tool for the conservation of acroporid corals

Corallivorous snail feeding is a common source of tissue loss for the threatened coral, Acropora palmata, accounting for roughly one-quarter of tissue loss in monitored study plots over seven years. In contrast with larger threats such as bleaching, disease, or storms, corallivory by Coralliophila abbreviata is one of the few direct sources of partial mortality that may be locally managed. We conducted a field experiment to explore the effectiveness and feasibility of snail removal. Long-term monitoring plots on six reefs in the upper Florida Keys were assigned to one of three removal treatments: (1) removal from A. palmata only, (2) removal from all host coral species, or (3) no-removal controls. During the initial removal in June 2011, 436 snails were removed from twelve 150 m² plots. Snails were removed three additional times during a seven month “removal phase”, then counted at five surveys over the next 19 months to track recolonization. At the conclusion, snails were collected, measured and sexed. Before-After-Control-Impact analysis revealed that both snail abundance and feeding scar prevalence were reduced in removal treatments compared to the control, but there was no difference between removal treatments. Recolonization by snails to baseline abundance is estimated to be 3.7 years and did not differ between removal treatments. Recolonization rate was significantly correlated with baseline snail abundance. Maximum snail size decreased from 47.0 mm to 34.6 mm in the removal treatments. The effort required to remove snails from A. palmata was 30 diver minutes per 150 m² plot, compared with 51 min to remove snails from all host corals. Since there was no additional benefit observed with removing snails from all host species, removals can be more efficiently focused on only A. palmata colonies and in areas where C. abbreviata abundance is high, to effectively conserve A. palmata in targeted areas.

Disease dynamics and potential mitigation among restored and wild staghorn coral, Acropora cervicornis

The threatened status (both ecologically and legally) of Caribbean staghorn coral, Acropora cervicornis, has prompted rapidly expanding efforts in culture and restocking, although tissue loss diseases continue to affect populations. In this study, disease surveillance and histopathological characterization were used to compare disease dynamics and conditions in both restored and extant wild populations. Disease had devastating effects on both wild and restored populations, but dynamics were highly variable and appeared to be site-specific with no significant differences in disease prevalence between wild versus restored sites. A subset of 20 haphazardly selected colonies at each site observed over a four-month period revealed widely varying disease incidence, although not between restored and wild sites, and a case fatality rate of 8%. A tropical storm was the only discernable environmental trigger associated with a consistent spike in incidence across all sites. Lastly, two field mitigation techniques, (1) excision of apparently healthy branch tips from a diseased colony, and (2) placement of a band of epoxy fully enclosing the diseased margin, gave equivocal results with no significant benefit detected for either treatment compared to controls. Tissue condition of associated samples was fair to very poor; unsuccessful mitigation treatment samples had severe degeneration of mesenterial filament cnidoglandular bands. Polyp mucocytes in all samples were infected with suspect rickettsia-like organisms; however, no bacterial aggregates were found. No histological differences were found between disease lesions with gross signs fitting literature descriptions of white-band disease (WBD) and rapid tissue loss (RTL). Overall, our results do not support differing disease quality, quantity, dynamics, nor health management strategies between restored and wild colonies of A. cervicornis in the Florida Keys.

In vitro metabolism of benzo[a]pyrene and dibenzo[def,p]chrysene in rodent and human hepatic microsomes

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and often carcinogenic contaminants released into the environment during natural and anthropogenic combustion processes. Benzo[a]pyrene (B[a]P) is the prototypical carcinogenic PAH, and dibenzo[def,p]chrysene (DBC) is a less prevalent, but highly potent transplacental carcinogenic PAH. Both are metabolically activated by isoforms of the cytochrome P450 enzyme superfamily to form reactive carcinogenic and cytotoxic metabolites. Metabolism of B[a]P and DBC was studied in hepatic microsomes of male Sprague-Dawley rats, naïve and pregnant female B6129SF1/J mice, and female humans, corresponding to available pharmacokinetic data. Michaelis-Menten saturation kinetic parameters including maximum rates of metabolism (VMAX, nmol/min/mg microsomal protein), affinity constants (KM, μM), and rates of intrinsic clearance (CLINT, ml/min/kg body weight) were calculated from substrate depletion data. CLINT was also estimated from substrate depletion data using the alternative in vitro half-life method. VMAX and CLINT were higher for B[a]P than DBC, regardless of species. Clearance for both B[a]P and DBC was highest in naïve female mice and lowest in female humans. Clearance rates of B[a]P and DBC in male rat were more similar to female human than to female mice. Clearance of DBC in liver microsomes from pregnant mice was reduced compared to naïve mice, consistent with reduced active P450 protein levels and elevated tissue concentrations and residence times for DBC observed in previous in vivo pharmacokinetic studies. These findings suggest that rats are a more appropriate model organism for human PAH metabolism, and that pregnancy's effects on metabolism should be further explored.

Retained asymptomatic third molars and risk for second molar pathology

Prophylactic extraction of unerupted asymptomatic third molars is the most common oral surgery procedure in the United States. However, limited evidence exists to justify its costs and associated morbidity. We analyzed data collected over 25 years from 416 adult men enrolled in the Veterans Affairs Dental Longitudinal Study to evaluate the association of retained asymptomatic third molars with risk of adjacent second molar pathology (caries and/or periodontitis), based on third molar status (i.e., absent, erupted, or unerupted). Unerupted molars were further categorized as either "soft tissue" or "bony" impacted. We found that the lowest prevalence and incidence of second molar pathology occurred when the adjacent third molar was absent. The presence of a third molar that was soft tissue impacted increased the risk of incident second molar pathology 4.88-fold (95% confidence interval: 2.62, 9.08). Having an erupted or "bony" impacted third molar increased the risk of incident second molar pathology by 1.74 (95% confidence interval: 1.34, 2.25) and 2.16 (95% confidence interval: 1.56, 2.99), respectively. The retention of third molars is associated with increased risk of second molar pathology in middle-aged and older adult men.

A device for recording automatic audio tape recording

Adaptation of a commercially available timer for use as a means of operating an audio tape recorder several times during the day is described. Data on a mother's rates of commanding her children were collected via both physically present observer and recorder methods in order to compare the usefulness of the recordings with direct observation. There was a high positive relationship between observer-recorder command rates, with the observer rates being consistently higher, when data were collected via both methods simultaneously as well as at different points in time.

Clinical and laboratory features of youth onset type 2 diabetes in Jamaica

OBJECTIVES

To assess the frequency of youth onset Type 2 diabetes mellitus (T2D) in Jamaica and the characteristics of youth with this form of diabetes.

METHODS

Patients from two major referral hospitals, diagnosed with diabetes before age 25 years and < 6 years prior to the study, were evaluated. Classification was based on the presence of GAD-65 and IA-2 diabetes autoantibodies (AB), fasting (FCP) and stimulated C-peptide (SCP) measurements, serum leptin and clinical phenotype as follows: (i) Type IA diabetes--AB+, (ii) Type lB diabetes--AB- and FCP < 230 pmol/l and/or SCP < 660pmol/l, (iii) Type 2 diabetes - AB- and FCP > 500 pmol/L and or SCP 2 1160 pmol/l (iv) Untypeable diabetes--AB- and FCP 230-500 pmol/l and or SCP 660-1160 pmol/l and (v) Lipoatrophic diabetes--clinical phenotype and serum leptin.

RESULTS

Fifty-eight participants (21M, 37F, age 20-8 years, duration of diabetes 2.6-2 years) were enrolled in the study. Using the classification criteria, Type 1 diabetes was the most common form of diabetes: 18 (31%) Type 1A, 18 (31%) Type IB. Overall 22% (13 patients) had T2D. Patients with T2D were more likely to be female, older at diagnosis, obese and have a higher blood pressure when compared to those with Type 1 diabetes. In logistic regression analysis, age of diabetes onset, gender BMI, systolic and diastolic blood pressure were significantly associated with T2D. Obesity measured by BMI was the strongest predictor of T2D.

CONCLUSIONS

While Type 1 diabetes was the predominant form of diabetes in this study, a significant proportion of Jamaicans with youth onset diabetes may have T2D. Obesity is the strongest clinical predictor of Type 2 diabetes in the young diabetic patient.

Protein pattern transfer for biosensor applications

This paper presents a very simple, industrially scalable method for transferring a high-resolution, biologically active protein pattern from one substrate to another. We demonstrate the transfer of a protein pattern formed initially by microcontact printing from a silicon surface (to which this form of printing is applicable) onto a glass or polymer substrate, almost independently of the surface/bulk properties of the second substrate. A very thin, spin-coated layer of a sugar is used to preserve the structure and organization of proteins during the subsequent plasma deposition of a siloxane polymer, after which the protein pattern could simply be peeled off the silicon substrate and glued onto any other desired substrate.

Cardiovascular risk profile in Caribbean youth with diabetes mellitus

OBJECTIVE

To assess the effect of diabetes mellitus type on conventional and novel cardiovascular risk factors in patients, diagnosed with diabetes from two major referral hospitals in Jamaica, before age 25 years and with diabetes duration < 6 years.

METHODS

Participants were classified based on the presence of GAD-65 and IA-2 autoantibodies, C-peptide, leptin and clinical phenotype. Trained observers obtained anthropometric measurements and sitting blood pressure. Fasting blood was taken for glucose, A1c, lipids, high sensitivity C-reactive protein and lipoprotein profile.

RESULTS

Fifty-eight participants (21M; 37F age 20 +/- 8 [Mean +/- SD] years, diabetes duration 2.6 +/- 2 years) were enrolled. Thirty-six had Type 1 diabetes (T1D), thirteen Type 2 diabetes (T2D), six were not typed and three had lipoatrophic diabetes. Patients with Type 2 diabetes (T2D) were more obese with a higher systolic blood pressure but a lower A1c than those with Type 1 diabetes (T1D). Total cholesterol, LDL-cholesterol, triglycerides, VLDL, LDL and HDL particle numbers were similar in patients with T1D and T2D. HDL-cholesterol and LDL and HDL particle sizes were lower in patients with T2D but differences were no longer significant after adjusting for BMI.

CONCLUSIONS

Risk factors for cardiovascular disease are common in patients with all forms of youth onset diabetes. Clinicians should therefore investigate these risk factors in their patients regardless of diabetes type.

Isolation of various forms of sterol beta-D-glucoside from the seed of Cycas circinalis: neurotoxicity and implications for ALS-parkinsonism dementia complex

The factors responsible for ALS-parkinsonism dementia complex (ALS-PDC), the unique neurological disorder of Guam, remain unresolved, but identification of causal factors could lead to clues for related neurodegenerative disorders elsewhere. Earlier studies focused on the consumption and toxicity of the seed of Cycas circinalis, a traditional staple of the indigenous diet, but found no convincing evidence for toxin-linked neurodegeneration. We have reassessed the issue in a series of in vitro bioassays designed to isolate non-water soluble compounds from washed cycad flour and have identified three sterol beta-d-glucosides as potential neurotoxins. These compounds give depolarizing field potentials in cortical slices, induce alterations in the activity of specific protein kinases, and cause release of glutamate. They are also highly toxic, leading to release of lactate dehydrogenase (LDH). Theaglycone form, however, is non-toxic. NMDA receptor antagonists block the actions of the sterol glucosides, but do not compete for binding to the NMDA receptor. The most probable mechanism leading to cell death may involve glutamate neuro/excitotoxicity. Mice fed cycad seed flour containing the isolated sterol glucosides show behavioral and neuropathological outcomes, including increased TdT-mediated biotin-dUTP nick-end labelling (TUNEL) positivity in various CNS regions. Astrocytes in culture showed increased caspase-3 labeling after exposure to sterol glucosides. The present results support the hypothesis that cycad consumption may be an important factor in the etiology of ALS-PDC and further suggest that some sterol glucosides may be involved in other neurodegenerative disorders.

Transplacental exposure to indole-3-carbinol induces sex-specific expression of CYP1A1 and CYP1B1 in the liver of Fischer 344 neonatal rats

Indole-3-carbinol (I3C), a naturally occurring component of broccoli, cabbage, and other members of the family Cruciferae, is a tumor modulator in several animal models that demonstrates significant chemoprevention against development of both spontaneous and chemically induced cancers while conversely eliciting tumor promoter effects in others. This study examines the disposition of I3C in the pregnant rat model, specifically to determine whether I3C can traverse the maternal placenta, and what effects, if any, are elicited in the neonate. We now report that dietary I3C treatment of pregnant female rats results in appearance of I3C acid condensation products in both maternal and neonatal livers. Livers from I3C-fed maternal rats showed CYP1A1 protein induction; however, no CYP1B1 protein was detected. No CYP1A1 or CYP1B1 protein was detected in the livers of pregnant controls or their offspring. We also report a sex-specific induction of CYP1A1 and CYP1B1 protein in livers from newborns born to I3C-fed dams. CYP1A1 protein was significantly induced in male neonatal liver, but not in females. Conversely, hepatic CYP1B1 protein was induced to high levels in female neonates, with no CYP1B1 protein detected in male littermates. Our results demonstrate that dietary I3C acid condensation products can cross the maternal placenta and differentially induce neonatal hepatic CYP1A1 and CYP1B1 in a sex-specific manner. The results highlight the potential of I3C to effect changes in the overall metabolic profile of xenobiotics to which the fetus is exposed transplacentally and indicate the possible involvement of sex-specific modulators in Ah receptor-mediated responses in this model.

Potentiometric titrations using dual microband electrodes

We present a novel method of analysis using potentiometric end-point detection and dual microband electrodes in generator-collector mode. The titrant is electrogenerated using either a constant current or a current that increases linearly with time, and the fluxes of reactive material rather than molar amounts are balanced. The advantage of the ramp current system over the constant current method is that all of the information needed for a full titration curve and a proper analysis can be obtained during a single scan. The method was applied to the determination of vitamin C with ferricyanide and to the determination of thiosulfate and sulfite with iodine using gold microband electrodes. As a new type of analysis, a potentiometric titration that uses dissolving silver microband electrodes in order to generate the titrant is demonstrated. The system was applied to the detection of chloride, iodide, thiosulfate and cyanide. The accuracy of the analysis is +/-10%, limited mainly by the present screen-printing process, and the method is well adapted for measurements on the millimolar scale.

Is the association between dietary fat intake and insulin resistance modified by physical activity?

The rising prevalence of type 2 diabetes, a condition associated with insulin resistance, is commonly attributed to changes in dietary patterns and physical activity levels in susceptible populations. However, few studies have described the independent effects of dietary intake and physical activity on the degree of insulin sensitivity within populations or examined the possibility of interactions between dietary factors and physical activity. This study was undertaken to describe the relationship between the quantity and pattern of dietary fat intake on fasting insulin levels (a marker of insulin sensitivity) and to investigate whether the association was modified by physical activity. A cross-sectional study of 815 nondiabetic men and women (30 to 71 years) recruited from a population-based sampling frame was undertaken. Diet was characterized using a semiquantitative food frequency questionnaire. Physical activity level (PAL), the ratio of total energy expenditure to basal metabolic rate, was estimated using individually calibrated heart rate monitoring, a method previously shown to be an objective and valid method for assessing total energy expenditure. In a linear regression model adjusted for total energy intake, total fat intake bordered on a significant association with fasting insulin (b = 0.000081; P =.058), and the polyunsaturated to saturated fat ratio (P:S ratio) of the diet was negatively associated with fasting insulin concentration (b = -0.37, P <.001). A negative association was observed between the PAL and fasting insulin (b = -0.12, P =.025). The association of the P:S ratio and PAL with fasting insulin remained significant when adjusted for each other and for total fat, total energy intake, body mass index (BMI), waist-to-hip ratio (WHR), age, sex, family history of diabetes, smoking status, and alcohol intake (P:S ratio, b = -0.24, P =.003; PAL, b = -0.13; P =.007). The association with total fat intake was no longer significant in this multivariate model (b = 6.7 x 10(-6); P =.858). There was no evidence for an interaction between total dietary fat intake and PAL (b = -0.000048; P =.243) or between the P:S ratio and PAL (b = -0.013; P =.949). These data demonstrate an independent association between the P:S ratio of the diet, the overall level of physical activity, and the fasting insulin concentration, a marker of insulin sensitivity. There was no evidence that the association between dietary fat intake and insulin resistance was modified by physical activity. The findings provide further support for efforts to promote increases in overall physical activity and modifications in the pattern of dietary fat intake in the whole population.

Evaluation of the chemopreventive potential of retinoids using a novel in vitro human prostate carcinogenesis model

The prevalence of prostatic intraepithelial neoplasia (PIN) and latent prostatic carcinoma, representing multiple steps in carcinogenesis and progression to invasive carcinoma, makes them relevant targets for prevention. A unique family of human prostate epithelial cell lines, which mimic steps in prostate carcinogenesis and progression, were used to evaluate the chemopreventive potential of all-trans-retinoic acid (RA) and N-(4-hydroxyphenyl)retinamide (4-HPR). The effects of RA and 4-HPR on anchorage-dependent growth of an immortalized, non-tumorigenic cell line RWPE-1 and two tumorigenic cell lines, WPE1-NB14 and WPE1-NB11, derived from RWPE-1 by exposure to N-methyl-N-nitrosourea (MNU), were examined. Both tumorigenic cell lines grow more rapidly than the parent RWPE-1 cell line in monolayer culture. Further, while RWPE-1 cells do not form colonies in agar, both tumorigenic cell lines do, with a colony forming efficiency (CFE) of 1.85 and 2.04% for WPE1-NB14 and WPE1-NB11 cells, respectively. Both RA and 4-HPR inhibited anchorage-dependent growth of all cell lines and anchorage-independent growth of WPE1-NB14 and WPE1-NB11 cells, in a dose-dependent manner, however, 10 times more RA than 4-HPR was required to produce the same effect. RWPE-1 cells are not invasive but WPE1-NB11 cells are significantly more invasive than WPE1-NB14 cells. Both RA and 4-HPR inhibited invasion in vitro by WPE1-NB11 and WPE1-NB14 cells where the more malignant WPE1-NB11 cells showed greater inhibition of invasion by 4-HPR than by RA. Overall, 4-HPR was more effective than RA in inhibiting growth and invasion but the response varied amongst the cell lines. These three cell lines mimic progressive steps in carcinogenesis and progression, from immortalized, non-tumorigenic RWPE-1 cells, to the less malignant WPE1-NB14 to the more malignant WPE1-NB11 cells, and provide powerful models for studies on secondary and tertiary prevention, i.e. promotion and progression stages, respectively, of prostate cancer.

Inhibition of tumor cell invasion and angiogenesis by motuporamines

Tissue invasion is an important determinant of angiogenesis and metastasis and constitutes an attractive target for cancer therapy. We have developed an assay to identify agents that inhibit invasion by mechanisms other than inhibition of cell attachment or cytotoxicity. A screen of marine sponge extracts identified motuporamines as micromolar inhibitors of invasion of basement membrane gels by MDA-231 breast carcinoma, PC-3 prostate carcinoma, and U-87 and U-251 glioma cells. Motuporamine C inhibits cell migration in monolayer cultures and impairs actin-mediated membrane ruffling at the leading edge of lamellae. Motuporamine C also reduces beta1-integrin activation, raising the possibility that it interferes with "inside-out" signaling to integrins. In addition, motuporamine C inhibits angiogenesis in an in vitro sprouting assay with human endothelial cells and an in vivo chick chorioallantoic membrane assay. The motuporamines show little or no toxicity or inhibition of cell proliferation, and they are structurally simple and easy to synthesize, making them attractive drug candidates.

Preattentive guidance of eye movements during triple conjunction search tasks: the effects of feature discriminability and saccadic amplitude

Eye movements were monitored during the performance of triple conjunction search tasks. Stimuli varied in color, shape, and orientation. Across trials, the target was either present or absent, and displays consisted of 6, 12, or 24 stimuli. Stimulus discriminability was manipulated for the shape dimension, with half of the participants seeing displays of Es and Fs (low-discriminability [LD] condition) and half seeing displays of Cs and Ts (high-discriminability [HD] condition). Participants in both conditions performed two search tasks. In the single-feature (SF) task, the target stimulus shared one feature with each of the distractors, whereas in the two-feature (TF) task, it shared two features with each distractor. An examination of saccadic endpoints revealed that participants were more likely to fixate on distractor stimuli sharing color (SF task) or color and shape (TF task) with the target. This was a robust finding, being observed across participants, saccades of different amplitudes and sequential position, and following short and long latencies to move. The extent to which participants made use of shape information increased with discriminability.

Indole-3-carbinol modulation of hepatic monooxygenases CYP1A1, CYP1A2 and FMO1 in guinea pig, mouse and rabbit

Indole-3-carbinol (I3C), a major component of cruciferous vegetables, has been shown to be chemoprotective against cancer in a number of animal models and is being evaluated as a potential agent to prevent breast cancer in healthy women. Some concern has been raised related to the long-term use of I3C, as in some models chronic dietary post-initiation exposures promote cancers. I3C administration to rats marked induces several cytochrome P450s (CYPs), especially CYP1A1 (approx. 25-fold), while at the same time inhibiting the expression of FMO1. The consequence is a marked shift in the metabolic profile of drugs such as nicotine and tamoxifen, that are substrates for both monooxygenases. Such an effect could lead to adverse drug reactions in humans. In order to determine if the effect of I3C was manifest in species other than the rat, we fed 2000-ppm I3C to male guinea pigs, mice and rabbits for a period of 4 weeks. In each species, induction of CYP1A1/1A2 expression was observed in the liver but little or no effect on FMO1 was evident, with the possible exception of the rabbit. These data demonstrate that the ability of I3C to both induce CYP1A1 and inhibit FMO1, as observed in the rat, may not be common to other mammals for which FMO1 is the major isoform in the liver.

A comparison of whole wheat, refined wheat and wheat bran as inhibitors of heterocyclic amines in the Salmonella mutagenicity assay and in the rat colonic aberrant crypt focus assay

Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic aberrant crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (aberrant crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P < 0.05), and fewer foci with two or three aberrant crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P < 0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0-48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P < 0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.

Inhibition of the G2 DNA damage checkpoint and of protein kinases Chk1 and Chk2 by the marine sponge alkaloid debromohymenialdisine

Cells can respond to DNA damage by activating checkpoints that delay cell cycle progression and allow time for DNA repair. Chemical inhibitors of the G(2) phase DNA damage checkpoint may be used as tools to understand better how the checkpoint is regulated and may be used to sensitize cancer cells to DNA-damaging therapies. However, few inhibitors are known. We used a cell-based assay to screen natural extracts for G(2) checkpoint inhibitors and identified debromohymenialdisine (DBH) from a marine sponge. DBH is distinct structurally from previously known G(2) checkpoint inhibitors. It inhibited the G(2) checkpoint with an IC(50) of 8 micrometer and showed moderate cytotoxicity (IC(50) = 25 micrometer) toward MCF-7 cells. DBH inhibited the checkpoint kinases Chk1 (IC(50) = 3 micrometer) and Chk2 (IC(50) = 3.5 micrometer) but not ataxia-telangiectasia mutated (ATM), ATM-Rad3-related protein, or DNA-dependent protein kinase in vitro, indicating that it blocks two major branches of the checkpoint pathway downstream of ATM. It did not cause the activation or inhibition of different signal transduction proteins, as determined by mobility shift analysis in Western blots, suggesting that it inhibits a narrow range of protein kinases in vivo.

The effect of Indian or Anglo dietary preference on the incidence of diabetes in Pima Indians

OBJECTIVE

In short-term studies, adoption of a traditional diet is associated with reduction in metabolic abnormalities often found in populations experiencing rapid lifestyle changes. We examined the long-term effects of a self-assessed traditional or nontraditional dietary pattern on the development of type 2 diabetes in 165 nondiabetic Pima Indians.

RESEARCH DESIGN AND METHODS

Dietary intake was assessed in 1988 by a quantitative food frequency method, and subjects were asked to classify their diet as "Indian," "Anglo," or "mixed." The Indian diet reflects a preference for Sonoran-style and traditional desert foods. The Anglo diet reflects a preference for non-Sonoran-style foods typical of the remaining regions of the U.S.

RESULTS

In women, the intake of complex carbohydrates, dietary fiber, insoluble fiber, vegetable proteins, and the proportion of total calories from complex carbohydrate and vegetable proteins were significantly higher (P < 0.05) in the Indian than in the Anglo diet. The mixed diet was intermediate in of all these constituents. In men, the intake for these nutrients was also higher in the Indian than in the Anglo group, but not significantly. Diabetes developed in 36 subjects (8 men and 28 women) during 6.2 years of follow-up (range 0.9-10.9). The crude incidence rates of diabetes were 23. 35, and 63 cases per 1,000 person-years in the Indian. mixed, and Anglo groups, respectively. After adjustment for age, sex, BMI, and total energy intake in a proportional hazards model, the risk of developing diabetes in the Anglo-diet group was 2.5 times as high (95%) CI 0.9-7.2) and the rate in the mixed-diet group was 1.3 times as high (0.6-3.3) as in the Indian-diet group.

CONCLUSIONS

This study suggests that the adoption of an Anglo diet may increase the risk of developing diabetes in Pima Indians, but it does not provide unequivocal evidence for or against this hypothesis.

Sphingolipid perturbations as mechanisms for fumonisin carcinogenesis

There is a great deal of evidence that altered sphingolipid metabolism is associated with fumonisin-induced animal diseases including increased apoptotic and oncotic necrosis, and carcinogenesis in rodent liver and kidney. The biochemical consequences of fumonisin disruption of sphingolipid metabolism most likely to alter cell regulation are increased free sphingoid bases and their 1-phosphates, alterations in complex sphingolipids, and decreased ceramide (CER) biosynthesis. Because free sphingoid bases and CER can induce cell death, the fumonisin inhibition of CER synthase can inhibit cell death induced by CER but promote free sphingoid base-induced cell death. Theoretically, at any time the balance between the intracellular concentration of effectors that protect cells from apoptosis (decreased CER, increased sphingosine 1-phosphate) and those that induce apoptosis (increased CER, free sphingoid bases, altered fatty acids) will determine the cellular response. Because the balance between the rates of apoptosis and proliferation is important in tumorigenesis, cells sensitive to the proliferative effect of decreased CER and increased sphingosine 1-phosphate may be selected to survive and proliferate when free sphingoid base concentration is not growth inhibitory. Conversely, when the increase in free sphingoid bases exceeds a cell's ability to convert sphinganine/sphingosine to dihydroceramide/CER or their sphingoid base 1-phosphate, then free sphingoid bases will accumulate. In this case cells that are sensitive to sphingoid base-induced growth arrest will die and insensitive cells will survive. If the cells selected to die are normal phenotypes and the cells selected to survive are abnormal, then cancer risk will increase.

Characterization of expressed full-length and truncated FMO2 from rhesus monkey

Flavin-containing monooxygenase (FMO) metabolizes a wide variety of nitrogen, sulfur, and phosphorous-containing xenobiotics. FMO2 is highly expressed in the lung of most mammals examined, but the protein has only recently been detected in humans, presumably due to a premature stop codon at AA472 in most individuals. In this study, full-length (mFMO2-535) and 3'-truncated (mFMO2-471) monkey FMO2 protein, produced by cDNA-mediated baculovirus expression, were characterized and compared with baculovirus-expressed rabbit FMO2 (rFMO2-535). Although baculovirus-expressed mFMO2-535 had properties similar to FMO in monkey lung microsomes and had catalytic properties similar to rFMO2-535, the expressed proteins differed in a number of properties in S-oxidation assays. Both enzymes had the same pH optima (pH 9.5); however, mFMO2-535 quickly lost activity at higher pH values whereas rFMO2-535 retained the majority of its activity. Also, mFMO2-535 was significantly less stable at elevated temperatures and in the presence of cholic acid but had greater activity in the presence of magnesium. mFMO2-535 had higher apparent K(m) and V(max)/K(m) values than rFMO2-535 did in N-oxygenation assays. mFMO2-471 was correctly targeted to the membrane fraction, but N- and S-oxygenation was not detected. Since the AA sequence identity of mFMO2 and human FMO2 is 97%, our results with mFMO2-535 suggest that individuals carrying the allele encoding full-length FMO2 are likely to have in vivo FMO2 activity. Such activity could result in marked differences in the metabolism, efficacy, and/or toxicity of drugs and xenobiotics for which lung is a portal of entry or target organ.

Validity of the CAGE questionnaire in an American Indian population

OBJECTIVE

This study evaluated the performance of the CAGE questionnaire (a set of four questions about alcoholism) in an American Indian population.

METHOD

We analyzed data from a cross-sectional study of 275 individuals (179 women) aged 21 years or older. Alcohol dependence was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised (DSM-III-R), based on a detailed psychiatric interview using the Schedule for Affective Disorders and Schizophrenia-Lifetime Version. Accuracy of the CAGE questionnaire was quantified as sensitivity, specificity, likelihood ratios and the area under receiver operating characteristics (ROC) curves, using the DSM-III-R diagnosis as the reference.

RESULTS

Of participants interviewed, 85% of men and 53% of women had a diagnosis of alcohol dependence by DSM-III-R. A CAGE score of > or = 2 had a sensitivity and specificity of 68% and 93%, respectively, in men and 62% and 79% in women, for the diagnosis of alcohol dependence. CAGE scores of 0, 1 and > or = 2 were associated with likelihood ratios of 0.3, 0.3 and 9.5, respectively, in men and 0.4, 0.7 and 1.5 in women. The area under the ROC curve was 81% for men and 75% for women.

CONCLUSIONS

These findings suggest that the CAGE questionnaire is a valid screening method, in this population, for identifying people likely to have alcohol dependence.

Human cell lines as an in vitro/in vivo model for prostate carcinogenesis and progression

BACKGROUND

The study of prostate carcinogenesis and tumor progression is made difficult by the lack of appropriate in vitro and in vivo models. High prevalence of prostatic intra-epithelial neoplasia and latent prostatic carcinoma, representing multiple steps in carcinogenesis to invasive carcinoma, are relevant targets for cancer prevention. From the RWPE-1, immortalized, non-tumorigenic, human prostate epithelial cell line, we have derived four tumorigenic cell lines with progressive malignant characteristics.

METHODS

Cell lines were derived by exposure of RWPE-1 to N-methyl-N-nitrosourea (MNU), selected and cloned in vivo and in vitro, and characterized by prostatic epithelial and differentiation markers, karyotype analysis, anchorage-independent growth, invasiveness, tumorigenicity, and pathology of the derived tumors.

RESULTS

Cytokeratins 8 and 18, androgen receptor, and prostate-specific antigen expression in response to androgen, confirm prostatic epithelial origin. RWPE-1 cells do not grow in agar and are not tumorigenic in mice, but the growth, tumorigenicity, and tumor pathology of the MNU cell lines correlate with their invasive ability. The WPE1-NA22 (least malignant) form small, well-differentiated, and WPE1-NB26 cells (most malignant) form large, poorly differentiated, invasive tumors. Overall, loss of heterozygosity for chromosomes 7q, 13q, 18q, and 22, and gain of 5, 9q, 11q, and 20, was observed. The MNU cell lines, in order of increasing malignancy are; WPE1-NA22, WPE1-NB14, WPE1-NB11, and WPE1-NB26.

CONCLUSIONS

This family of cell lines with a common lineage represents a unique and relevant model which mimics stages in prostatic intra-epithelial neoplasia (PIN) and progression to invasive cancer, and can be used to study carcinogenesis, progression, intervention, and chemoprevention.

Fumonisin B1 promotes aflatoxin B1 and N-methyl-N'-nitro-nitrosoguanidine-initiated liver tumors in rainbow trout

Laboratory studies have described the carcinogenicity of fumonisin B1 (FB1) in rodents and epidemiological evidence suggests an association between FB1 (a mycotoxin produced by Fusarium moniliforme) and cancer in humans. This study was designed to reveal in rainbow trout, a species with very low spontaneous tumor incidence, if FB1 was (i) a complete carcinogen, in the absence of an initiator; (ii) a promoter of liver tumors in fish initiated as fry with aflatoxin B1 (AFB1); and (iii) a promoter of liver, kidney, stomach, or swim bladder tumors in fish initiated as fry with N-methyl-N'-nitro-nitrosoguanidine (MNNG). FB1 was not a complete carcinogen in trout. No tumors were observed in any tissue of fish fed diets containing 0, 3.2, 23, or 104 ppm FB1 for a total of 34 weeks (4 weeks FB1 exposure, 2 weeks outgrowth on control diet, followed by 30 weeks FB1 diet) in the absence of a known initiator. FB1 promoted AFB1 initiated liver tumors in fish fed > or = 23 ppm FB1 for 42 weeks. A 1-week pretreatment of FB1 did not alter the amount of liver [3H]AFB1 DNA adducts, which suggests that short-term exposure to FB1 will not alter phase I or phase II metabolism of AFB1. In MNNG-initiated fish, liver tumors were promoted in the 104 ppm FB1 treatment (42 weeks), but FB1 did not promote tumors in any other tissue. Tumor incidence decreased in kidney and stomach in the 104 ppm FB1 treatment of MNNG-initiated trout. The FB1 promotional activity in AFB1-initiated fish was correlated with disruption of sphingolipid metabolism, suggesting that alterations in associated sphingolipid signaling pathways are potentially responsible for the promotional activity of FB1 in AFB1-initiated fish.

Electron transfer mediated by glucose oxidase at the liquid/liquid interface

In order to establish an experimental basis for exploring the reactivity of membrane-bound redox enzymes using electrochemistry at an organic/aqueous interface, the reactivity of glucose oxidase adsorbed at the dichloroethane/water interface has been studied. Turnover of glucose in the aqueous phase mediated by dimethyl ferricenium electrogenerated in the organic phase was measured by measuring the feedback current caused by recycling the mediator as the generator electrode approached close to the interface from the organic side. An unexpected self-exchange reaction of the ferrocene at the interface was suppressed by adsorption of a surfactant. The interfacial enzyme reaction could be distinguished from reaction within the bulk of the aqueous phase. Reaction within a protein-surfactant film formed at the interface is conjectured.

Glánvillic acids A and B and methyl capucinoate A, new metabolites isolated from the Caribbean sponges Plakortis halichondrioides and Plakinastrella onkodes

Glánvillic acids A (2) and B (3) and the cytotoxic cyclic peroxides methyl capucinoate A (4) and 5 were isolated from the Dominican marine sponges Plakortis halichondrioides and Plakinastrella onkodes, respectively. The structures have been elucidated by spectroscopic analysis of 4 and 5 and of methyl glánvillates A (6) and B (7).

The psoralens adversely affect reproductive function in male wistar rats

The psoralens occur naturally in produce and are widely used in skin therapy. Studies show that 5-methoxypsoralen and 8-methoxypsoralen reduced birth rates in rats. We determined the effect of psoralens on reproductive function in male rats. Male Wistar rats were dosed daily with 5-methoxypsoralen or 8-methoxypsoralen (75 or 150 mg/kg, p.o.), or vehicle control. Treated males had significantly smaller pituitary glands, fewer sperm per ejaculate, and fewer sperm in the vasa defferentia and epididymides than controls. Dosing significantly elevated levels of testosterone and increased relative testis weight, but did not directly affect testicular weight. Females bred to dosed males required more time to become pregnant, and these males required more breeding attempts. The findings demonstrate the importance of determining the potential risk for infertility and/or birth defects in humans who are exposed to therapeutic, dietary, or occupational psoralens.

4-hydroxy-2',4',6'-trichlorobiphenyl and 4-hydroxy-2',3',4',5'-tetrachlorobiphenyl are estrogenic in rainbow trout

Many natural and synthetic xenobiotics are known to interact with endocrine systems of animals. Various hydroxylated metabolites of persistent polychlorinated biphenyl contaminants (hydroxy-polychlorinated biphenyls [OH-PCBs]) have been shown to have agonist or antagonist interactions with estrogen receptors (ERs). In this study, 4-hydroxy-2',4',6'-trichlorobiphenyl (OH-PCB 30) and 4-hydroxy-2',3',4',5'-tetrachlorobiphenyl (OH-PCB 61), and the natural estrogen 17 beta-estradiol (E2) and estrone (E1), were incorporated into diet and fed to juvenile rainbow trout. The production of vitellogenin (VTG), an egg yolk protein precursor in oviparous animals, was used as a marker of hepatic ER binding. All compounds induced plasma VTG in a dose-dependent manner, with maximal levels of approximately 5 mg VTG/ml plasma induced by E2, E1, and OH-PCB 30. Maximum plasma VTG of 0.048 mg/ml in the highest dose (50 mg/kg) of OH-PCB 61 was approximately 100-fold lower than natural estrogens and OH-PCB 30. At doses that induced submaximal VTG, E1 was two- to threefold less potent, and OH-PCBs were up to 500-fold less potent, than E2. Sex differences in VTG synthesis were apparent at weakly estrogenic doses, but not at maximal VTG-inducing doses. Predictions from previous receptor-binding studies underestimated the maximum estrogenic response of OH-PCB 30 in trout, which was achieved with a dose 10 times higher than E2. Differences in plasma VTG induction by OH-PCB 30 and OH-PCB 61 support in vitro predictions that the degree and position of chlorination are important for ER activation. Neither mixtures of estrogens nor OH-PCBs resulted in synergistic VTG induction.

3,3'-diindolylmethane, a major condensation product of indole-3-carbinol, is a potent estrogen in the rainbow trout

Indole-3-carbinol (I3C), a compound found in Brassica vegetables has been widely studied for its chemopreventive properties. I3C has been shown to block tumor initiation and promotion; however, it also acts as a tumor promoter. I3C and some of its acid condensation products, particularly 3,3'-diindolylmethane (I33'), have exhibited antiestrogenic properties. We report that I33' acts as an estrogen in the rainbow trout liver in vitro and in vivo by inducing vitellogenin (Vg), a well-characterized biomarker for estrogens. Precision-cut liver slices from male rainbow trout, Oncorhynchus mykiss, were incubated at 14 degrees C for 96 h in media containing I3C, I33', or a mixture of I3C acid condensation products (RXN) (0-250 microM). I33' and RXN increased Vg levels in rainbow trout liver slices by over 300- and 20-fold, respectively, vs vehicle. The efficacy of I33' induction of Vg was comparable to 17 beta-estradiol (E(2)) with 2500-fold less potency. I33' and E(2) cotreatment resulted in additive Vg induction. Tamoxifen completely inhibited I33'-induced Vg induction, suggesting that Vg induction by I33' is entirely through the estrogen receptor. In vivo, juvenile male rainbow trout were fed I3C, RXN (0-2000 mg/kg), or I33' (0-250 mg/kg) for 2 weeks. At 2000 mg/kg, I3C induced Vg by over 100,000-fold compared to controls, which was comparable to 5 mg/kg 17 beta-estradiol (the dose resulting in maximum induction). I33' was five times as potent as I3C with equal efficacy. The potency of RXN was only 5% of I3C. Again, I33' and E(2) cotreatment resulted in additive Vg induction. I33' may have accounted for Vg increases observed in trout fed I3C as it is present in liver after oral dosing at concentrations (70 microM) expected to maximally induce Vg. In trout, results in vitro and in vivo document that I33' is estrogenic, consistent with our hypothesis that I3C promotes liver cancer in trout by estrogenic pathways.

CL22 - a novel cationic peptide for efficient transfection of mammalian cells

Condensing peptide-DNA complexes have great potential as nonviral agents for gene delivery. To date, however, such complexes have given transfection activities greatly inferior to adenovirus and somewhat inferior to cationic lipid-DNA complexes, even for cell lines and primary cells in vitro. We report here the identification of a novel condensing peptide, CL22, which forms DNA complexes that efficiently transfect many cell lines, as well as primary dendritic and endothelial cells. We report studies with sequence and structure variants that define some properties of the peptide that contribute to efficient transfection. We demonstrate that the superior transfection activity of CL22 compared with other DNA condensing peptides is conferred at a step after uptake of the complexes into cells. We show that CL22-DNA complexes have transfection activity that is at least equivalent to the best available nonviral agents.

Electrochemical titrations of thiosulfate, sulfite, dichromate and permanganate using dual microband electrodes

Applications of titration using dual gold microband electrodes in generator-collector mode are presented. The main advantage is that the method dispenses with the need for accurate volume measurements and reagent preparation: rather than balancing of molar amounts, the fluxes of analyte and titrant are balanced instead. The titrant is generated electrochemically and the end-point is detected amperometrically by the appearance of a current due to the presence of the titrant at the other band. The aim is to show the versatility and capability of the method that employs disposable mass-produced electrodes and uses pulsed motion of the electrode before a measurement to renew the boundary conditions. The titration of ascorbic acid (vitamin C) with ferricyanide, which has been a model system, was extended to the determination of thiosulfate and sulfite with iodine and the determination of dichromate and permanganate with iron(II). The accuracy, limited by the present fabrication reproducibility of the disposable electrodes, is +/- 10%. The results demonstrate that the method is effective even with a very simple set-up, and the actual time needed for common titrations is significantly decreased. These examples demonstrate a comprehensive basis for further development and applications, including standard titrations in industry.