Novel growth and properties of GaAs nanowires on Si substrates

Straight, vertically aligned GaAs nanowires were grown on Si(111) substrates coated with thin GaAs buffer layers. We find that the V/III precursor ratio and growth temperature are crucial factors influencing the morphology and quality of buffer layers. A double layer structure, consisting of a thin initial layer grown at low V/III ratio and low temperature followed by a layer grown at high V/III ratio and high temperature, is crucial for achieving straight, vertically aligned GaAs nanowires on Si(111) substrates. An in situ annealing step at high temperature after buffer layer growth improves the surface and structural properties of the buffer layer, which further improves the morphology of the GaAs nanowire growth. Through such optimizations we show that vertically aligned GaAs nanowires can be fabricated on Si(111) substrates and achieve the same structural and optical properties as GaAs nanowires grown directly on GaAs(111)B substrates.

Test characteristics of neck fullness and witnessed neck pulsations in the diagnosis of typical AV nodal reentrant tachycardia

BACKGROUND

Claims in the medical literature suggest that neck fullness and witnessed neck pulsations are useful in the diagnosis of typical AV nodal reentrant tachycardia (AVNRT).

HYPOTHESIS

Neck fullness and witnessed neck pulsations have a high positive predictive value in the diagnosis of typical AVNRT.

METHODS

We performed a cross-sectional study of consecutive patients with palpitations presenting to a single electrophysiology (EP) laboratory over a 1 year period. Each patient underwent a standard questionnaire regarding neck fullness and/or witnessed neck pulsations during their palpitations. The reference standard for diagnosis was determined by electrocardiogram and invasive EP studies.

RESULTS

Comparing typical AVNRT to atrial fibrillation (AF) or atrial flutter (AFL) patients, the proportions with neck fullness and witnessed neck pulsations did not significantly differ: in the best case scenario (using the upper end of the 95% confidence interval (CI), none of the positive or negative predictive values exceeded 79%. After restricting the population to those with supraventricular tachycardia (SVT) other than AF or AFL, neck fullness again exhibited poor test characteristics; however, witnessed neck pulsations exhibited a specificity of 97% (95% CI: 90%-100%) and a positive predictive value of 83% (95% CI: 52%-98%). After adjustment for potential confounders, SVT patients with witnessed neck pulsations had a seven-fold greater odds of having typical AVNRT, p = 0.029.

CONCLUSIONS

Although neither neck fullness nor witnessed neck pulsations are useful in distinguishing typical AVNRT from AF or AFL, witnessed neck pulsations are specific for the presence of typical AVNRT among those with SVT.

Intracardiac and extracardiac markers of inflammation during atrial fibrillation

BACKGROUND

A decrease in inflammation after cure of atrial arrhythmias suggests that such arrhythmias are proinflammatory, and lower inflammatory marker levels in the coronary sinus suggest that atrial arrhythmias result in intracardiac appropriation of inflammatory cytokines.

OBJECTIVE

The purpose of this study was to investigate the effect of atrial fibrillation on inflammatory markers drawn from intracardiac and extracardiac chambers.

METHODS

We performed a case-control study of 167 AF patients and 207 controls. Blood from intracardiac and extracardiac sites was obtained from a subset of patients undergoing curative AF ablation (n = 46).

RESULTS

No significant differences in C-reactive protein (CRP) or interleukin-6 (IL-6) levels were seen between patients with and those without a history of AF. Both levels were significantly higher when blood was drawn during AF than during sinus rhythm: median CRP 3.1 mg/dL (interquartile range [IQR] 1.0-6.0) versus 1.7 mg/dL (IQR 0.7-3.9, P = .0005); median IL-6 2.3 ng/mL (IQR 1.5-3.9) versus 1.5 ng/mL (IQR 0.7-2.5, P = .007). This finding persisted after adjusting for potential confounders. AF ablation patients in AF exhibited a positive median left atrial minus coronary sinus gradient CRP (0.3 mg/dL, IQR -0.03-1.1), whereas those in sinus rhythm had a negative median left atrial minus coronary sinus gradient CRP (-0.2, IQR -0.8-[-0.02], P = .01). Femoral artery minus femoral vein gradients in AF versus sinus rhythm did not show any differences.

CONCLUSION

AF at the time of the blood draw, rather than a history of AF, was independently associated with inflammation. Differences in transcardiac gradients suggest that AF results in sequestration of inflammatory cytokines in the heart.

Efficacy of antiarrhythmic drugs in arrhythmogenic right ventricular cardiomyopathy: a report from the North American ARVC Registry

OBJECTIVES

This study sought to examine the efficacy of empiric antiarrhythmic drugs in a rigorously characterized cohort of arrhythmogenic right ventricular cardiomyopathy (ARVC) patients.

BACKGROUND

Antiarrhythmic drugs are important in protecting against ventricular arrhythmias in ARVC, but no studies have provided data in a group rigorously screened for the disease.

METHODS

Antiarrhythmic medicines were examined in all subjects with implantable cardioverter-defibrillators (ICDs) enrolled in the North American ARVC Registry. A Cox proportional hazards model was used to account for time on each drug, and a hierarchical analysis was performed for repeated measures within individuals.

RESULTS

Ninety-five patients were studied, with a mean follow-up of 480 +/- 389 days. Fifty-eight (61%) received beta-blockers, and these medicines were not associated with an increased or decreased risk of ventricular arrhythmias. Sotalol was associated with a greater risk of any clinically relevant ventricular arrhythmia as defined by sustained ventricular tachycardia or ICD therapy (hazard ratio [HR]: 2.55, 95% confidence interval [CI]: 1.02 to 6.39, p = 0.045), but this was not statistically significant after adjusting for potential confounders. An increased risk of any ICD shock and first clinically relevant ventricular arrhythmia while on sotalol remained significant after multivariable adjustment. Those on amiodarone (n = 10) had a significantly lower risk of any clinically relevant ventricular arrhythmia (HR: 0.25, 95% CI: 0.07 to 0.95, p = 0.041), a finding that remained significant after multivariable adjustment.

CONCLUSIONS

In a cohort of well-characterized ARVC subjects, neither beta-blockers nor sotalol seemed to be protective. Evidence from a small number of patients suggests that amiodarone has superior efficacy in preventing ventricular arrhythmias.

Altered neurometabolites and motor integration in children exposed to methamphetamine in utero

Methamphetamine (METH) is a neurotoxic drug. This study aimed to evaluate brain metabolite levels and cognitive function in young children with prenatal METH exposure. 101 children ages 3-4 years were evaluated with neuropsychological tests and underwent proton magnetic resonance spectroscopy ((1)H-MRS) without sedation. Complete datasets from 49 METH-exposed and 49 controls who completed the neuropsychological test battery, and 38 METH-exposed and 37 controls with high-quality MR spectra are reported here. Despite similar physical characteristics (including head circumference), global cognitive function (on Stanford-Binet), parental education, intelligence, mood, and socioeconomic status, METH-exposed children had higher total creatine (tCr: +7%, p=0.003), N-acetyl compounds (NA: +4.3%, p=0.004) and glutamate+glutamine (GLX: +9.6%, p=0.02) concentrations in the frontal white matter, but lower myoinositol (MI: -7%, p=0.01) and MI/tCr (-7.5%, p=0.03) in the thalamus, than control children. The higher frontal white matter NA in the METH-exposed children was due to the higher NA in the METH-exposed girls (+10.2%, p=0.003), but not the boys (+0.8%) compared to sex-matched controls. Furthermore, the METH-exposed children had poorer performance on a visual motor integration (VMI) task, which correlated with lower MI in the thalamus (r=0.26, p=0.03). The higher NA, tCr and GLX concentrations suggest higher neuronal density or cellular compactness in the white matter, especially in the girls, whereas the lower MI suggests lower glial content in the thalamus of these METH-expose children. These findings combined with their poorer performance on VMI also suggest accelerated but aberrant neuronal and glial development in these brain regions.

Water quality in the near coastal waters of the Gulf of Mexico affected by Hurricane Katrina: before and after the storm

Water quality was assessed following Hurricane Katrina in the affected waters of Alabama, Mississippi, and Louisiana. Post-landfall water quality was compared to pre-hurricane conditions using indicators assessed by EPA's National Coastal Assessment program and additional indicators of contaminants in water and pathogens. Water quality data collected after Hurricane Katrina suggest that the coastal waters affected by the storm exhibited higher salinity and concentrations of chlorophyll a, dissolved inorganic phosphorus, and total suspended solids following the storm compared to the previous 5-year averages. Higher bottom dissolved oxygen concentrations and light attenuation were also observed. Contaminant concentrations measured in the water column were very low or undetectable, as were the presence of pathogens. Overall water quality did not significantly differ from water quality assessed in the five years preceding the storm. Statistical analyses indicate that use of a probabilistic survey design is appropriate for making pre-storm and post storm comparisons for water quality condition on an areal basis.

The effect of V/III ratio and catalyst particle size on the crystal structure and optical properties of InP nanowires

InP nanowires were grown on 111B InP substrates by metal-organic chemical vapour deposition in the presence of colloidal gold particles as catalysts. Transmission electron microscopy and photoluminescence measurements were carried out to investigate the effects of V/III ratio and nanowire diameter on structural and optical properties. Results show that InP nanowires grow preferably in the wurtzite crystal structure than the zinc blende crystal structure with increasing V/III ratio or decreasing diameter. Additionally, time-resolved photoluminescence (TRPL) studies have revealed that wurtzite nanowires show longer recombination lifetimes of approximately 2500 ps with notably higher quantum efficiencies.

Assessing coastal waters of American Samoa: territory-wide water quality data provide a critical "big-picture" view for this tropical archipelago

The coastal waters of American Samoa's five high islands (Tutuila, Aunu'u, Ofu, Olosega, and Ta'u) were surveyed in 2004 using a probabilistic design. Water quality data were collected from the near-shore coastal habitat, defined as all near-shore coastal waters including embayments, extending out to 1/4 mile off-shore. Hydrography and water column samples were collected, and water quality data were compared to the Territorial water quality standards for pH, dissolved oxygen (DO), Enterococcus, chlorophyll a, water clarity, total nitrogen, and total phosphorus. All station measurements for pH, DO, and Enterococcus satisfied the local water quality standards, although some fraction of the Territory could not be assessed for either DO or Enterococcus. With respect to chlorophyll a, 66 +/- 18% of Territory coastal waters complied with the standard, while 34 +/- 18% failed to comply with the standard. For water clarity, 54 +/- 18% of the Territorial waters complied with the standard while 42 +/- 7% failed to comply. Territorial waters satisfied the standards for total nitrogen and phosphorus 72 +/- 17% and 92 +/- 10%, respectively. These data provide the first "big-picture" view of water quality in the near shore region around the high islands of American Samoa. While the picture is encouraging, these data suggest emerging water quality concerns.

Relation of fish and shellfish distributions to habitat and water quality in the Mobile Bay estuary, USA

The Mobile Bay estuary in the northern Gulf of Mexico provides a rich habitat for many fish and shellfish, including those identified as economically and ecologically important. The National Estuary Program in Mobile Bay has focused on restoration of degraded estuarine habitat on which these species depend. To support this effort, we used statistical techniques of ordination, cluster analysis, and discriminant analysis to relate distributions of individual fish and shellfish species and species assemblages to two dozen water quality and habitat variables in a geo-referenced database. Species appeared to respond to dominant gradients of low to high salinity and upland to offshore habitat area; many of the 15 communities identified via cluster analysis showed aggregated spatial distributions that could be related to habitat characteristics. Species in the Mobile River Delta were distinct from those in other areas of the estuary. This analysis supports habitat management in the Mobile Bay estuary; however, due to mobility of organisms among sampling locations and the dynamic environmental conditions in estuaries, we conclude that the analyses presented here are most appropriate for an evaluation of the estuary as a whole.

Protracted CRP elevation after atrial fibrillation ablation

BACKGROUND

Atrial fibrillation (AF) has been linked to an inflammatory process detected through various biomarkers, including C-Reactive Protein (CRP). Early recurrence of AF within the first 3 months after curative AF ablation is not felt to reflect success or failure of the procedure. We hypothesized that this early recurrence is due to an inflammatory response to the ablation itself. We therefore sought to evaluate levels of CRP after AF ablation.

METHODS

We prospectively enrolled subjects undergoing AF ablation. A control group of patients undergoing ablation for supraventricular tachycardia (SVT) was also enrolled. Each patient had CRP drawn on the day of the procedure (prior to ablation) and during their first follow-up (median 49 days, interquartile range [IQR] 37-93) and second follow-up (median 147 days, IQR 141-257) clinic visits. Patient interviews were performed and medical histories reviewed for evidence of recurrent AF prior to the first follow-up.

RESULTS

CRP levels significantly increased from baseline to first follow-up in the AF ablation group (P = 0.0017). CRP did not significantly change after SVT ablation (P = 0.92). Seventeen (45%) of the AF subjects exhibited recurrence of AF prior to first follow-up. After adjusting for multiple potential confounders, AF ablation patients with recurrent AF prior to their first follow-up had a statistically significant greater odds of having an increase in CRP (OR 21, 95% CI 1.1-417, P = 0.045).

CONCLUSIONS

AF ablation generates an inflammatory response that persists for several weeks. This inflammation may explain early recurrence of AF after curative ablation.

Effects of being a peer-leader in an eating disorder prevention program: can we further reduce eating disorder risk factors?

Studies regarding the effect of peer-leadership on peer-leaders in prevention programs remain extremely limited. In this study, 83 undergraduate sorority members, who previously participated in the program, served as peer-leaders for an eating disorder prevention program. Peer-leaders attended 9 hours of training and then led two 2-hour sessions. Leaders showed decreases (beyond participation in earlier studies) in dietary restraint, bulimic pathology, body dissatisfaction, and thin-ideal internalization from pre-training through 7-week follow up. Results from this exploratory study suggest that peer-leaders who participate in a program and subsequently lead it may experience additional benefits compared to participation in the program alone.

Tuning spin properties of excitons in single CdTe quantum dots by annealing

Using polarization-resolved photoluminescence imaging in external magnetic fields we measure statistically significant distributions of exchange splitting, diamagnetic shift and effective g-factor of excitons in tens of single CdTe quantum dots. Comparison between the as-grown and annealed structures shows strong suppression of ensemble inhomogeneities, with the average exchange splitting reduced by half and significant narrowing of the g-factor distribution. Remarkably, the average value of the excitonic g-factor remains unchanged. This unique ability to yield highly uniform quantum dot ensembles without hampering the exciton Zeeman splitting makes annealing a highly attractive means for tuning the spin properties of quantum dot excitons.

A first-degree family history in lone atrial fibrillation patients

BACKGROUND

Atrial fibrillation (AF) may be due to an inherited trait, particularly in lone AF patients. A family history of AF in lone AF patients has not previously been compared with a family history of patients with AF and established risk factors (non-lone AF).

OBJECTIVE

The purpose of this study was to compare the frequency of having a first-degree relative with AF in lone and non-lone AF patients.

METHODS

We performed a case-control study of consecutive subjects presenting to a single electrophysiology laboratory. A convenience sample of subjects with no known arrhythmias was also enrolled.

RESULTS

Four hundred twenty-nine subjects were enrolled: 136 had AF (54 with lone AF), 84 had atrial flutter, 158 had other supraventricular arrhythmias, and 51 had no known arrhythmias. Significantly more subjects with AF reported a first-degree family history of AF compared with the remainder of the cohort (25% vs. 5%; P <.001). In multivariable analysis adjusting for potential confounders, AF patients had a 6-fold greater odds of having a family member with AF (95% confidence interval [CI] 2.93-12.7; P <.001). Lone AF patients had a first-degree family member with AF substantially more often than those with non-lone AF (41% vs. 14%; P <.001). After adjusting for potential confounders, lone AF patients remained significantly more likely than other AF patients to have a first-degree relative with AF (OR 7.2; 95% CI 2.1-24.7; P = .002).

CONCLUSION

Lone AF patients have a first-degree family member with AF substantially more often than other AF patients. This suggests that an inherited trait may be particularly important in this subgroup of patients.

Comparison of several traps for catching German cockroaches (Dictyoptera: Blattellidae) under laboratory conditions

German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), catch by five types of traps and modifications of each, were tested under controlled laboratory conditions. Cockroach catch differed significantly among traps. Lo-line trap caught the greatest number of cockroaches in the test arena for each size class (23% small nymphs, 39% of gravid females, and 60% of other size classes in the experimental arena). Jar traps caught the least number of cockroaches in the test arena for each size class (range, 7-23% of each size class trapped). Modifications of traps also altered catch of cockroaches. Food bait tablets increased catch significantly; however, increases were small (<10%). Size of traps did not affect catch; whole traps or half traps caught the same number of cockroaches. Jar traps were much less effective than sticky traps, catching only half the number of cockroaches as sticky traps. A thin layer of petrolatum was a more effective barrier in jar traps to cockroach escape than powdered Olancha clay. Traps with petrolatum caught about twice as many cockroaches as traps with clay. Trapping of any of six life stages was not significantly affected by catch of any of the other stages. Rather, trap catch of each life stage was dependent on the number of that life stage available in the experimental arenas. In conclusion, of the traps tested, the Lo-line trap was the most sensitive for measuring cockroach catch, whereas the Detector trap (one third of trap) was the most economical trap (greatest sensitivity for lowest cost).

Somatoform dissociation in depersonalization disorder

Along with psychoform dissociation, somatoform dissociation has been put forth as a core aspect of dissociative states, possibly as reliable as psychoform dissociation in the screening for dissociative disorders. The goal of this study was to investigate the prominence and correlates of somatoform dissociation in one of the major Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) dissociative disorders, depersonalization disorder (DPD). A total of 54 adults with DPD and 47 healthy control participants free of lifetime Axis I and II disorders were administered the 20-item Somatoform Dissociation Questionnaire (SDQ) as well as the Dissociative Experiences Scale, the Cambridge Depersonalization Scale, and the Childhood Trauma Questionnaire-Short Form. Somatoform dissociation scores were statistically significantly, but clinically only modestly, elevated in the DPD as compared to the healthy control group. SDQ items significantly elevated in the DPD group were mostly perceptual in nature. Depersonalization scores were significantly correlated with somatoform dissociation in the DPD group, whereas absorption and amnesia scores were not. With respect to childhood interpersonal trauma, although emotional abuse was significantly associated with depersonalization severity, none of the 5 categories of trauma were significantly associated with somatoform dissociation in the DPD group. In conclusion, somatoform dissociation is modest in DPD, and the SDQ is a weak instrument for the screening of dissociation in this disorder, detecting only one third of the sample when using the traditional SDQ cutoff score of 30.

Dissection of silencing signal movement in Arabidopsis

In our recent paper in Plant Cell, we examined the phenomenon of non-cell autonomous RNA silencing through a genetic screen of the requirements for cell-to-cell signal movement.1 We found a requirement for components of the nuclear and trans-acting RNA silencing pathways in blocking or enhancing the spread of silencing and identified a new SNF2 domain-containing protein, CLSY1, in the nuclear RNA silencing pathway. Here we discuss our data from a broader perspective of other recently published papers.

Markers of inflammation before and after curative ablation of atrial flutter

BACKGROUND

Atrial arrhythmias are associated with inflammation. The cause and effect of the association are unknown.

OBJECTIVE

The purpose of this study was to test the hypothesis that atrial tachyarrhythmias contribute to inflammation.

METHODS

We performed a prospective observational study wherein C-reactive protein (CRP) and interleukin-6 (IL-6) levels from the femoral vein and coronary sinus (CS) were compared before curative ablation for atrial flutter (AFL; n = 59) and paroxysmal supraventricular tachycardia (SVT; n = 110). Follow-up levels were obtained at 1 and 6 months.

RESULTS

Peripheral levels of both biomarkers were significantly higher in the AFL group. After multivariate adjustment, only those in the AFL group who presented in AFL or atrial fibrillation (AF) had significantly elevated CRP levels (odds ratio 1.26; P = .033). Levels of each marker were similar in the CS and peripheral blood in the SVT group; in the AFL group, both CRP and IL-6 were significantly lower in the CS than in the periphery (P = .0076 and P = .0021, respectively). CRP was significantly lower a median of 47 days after AFL ablation (from a median of 6.28 mg/L to a median of 2.92 mg/L; P = .028) and remained reduced at second follow-up. IL-6 decreased across three time points after AFL ablation (P = .002). No reduction in inflammatory biomarkers was observed after SVT ablation.

CONCLUSIONS

CRP and IL-6 levels are elevated in patients presenting in AFL. Given the lower CS values in these patients, their origin appears to be systemic rather than cardiac. Because these levels significantly fall after ablation of AFL, the atrial tachyarrhythmia appears to be the cause (not the effect) of the inflammation.

Factors associated with resilience in healthy adults

Mature defenses comprise one well-validated indicator of resilience. We investigated the relationships of resilience to trauma, attachment, temperament, cortisol, and cognitive performance in adult healthy volunteers. Participants were administered the Defense Style Questionnaire; the Relationship Questionnaire; the Childhood Trauma Questionnaire, and the Tridimensional Personality Questionnaire. Cortisol determinations included 24-h urinary, mean hourly plasma, response to low-dose dexamethasone suppression, and reactivity to the Trier social stress test (TSST). Mathematical performance during the TSST was quantified. Twenty-five women and 29 men participated. Resilience was significantly negatively correlated with childhood interpersonal trauma and with harm avoidance. Resilience was significantly positively correlated with urinary cortisol, secure attachment, reward dependence, and superior performance. In a linear regression analysis, the strongest predictor of resilience was childhood trauma, followed by math performance under stress and harm avoidance. We conclude that in young adults without manifest psychiatric disorder, resilience was associated with developmental, biological, and cognitive measures which merit further investigation.

A classification of U.S. estuaries based on physical and hydrologic attributes

A classification of U.S. estuaries is presented based on estuarine characteristics that have been identified as important for quantifying stressor-response relationships in coastal systems. Estuaries within a class have similar physical and hydrologic characteristics and would be expected to demonstrate similar biological responses to stressor loads from the adjacent watersheds. Nine classes of estuaries were identified by applying cluster analysis to a database for 138 U.S. estuarine drainage areas. The database included physical measures of estuarine areas, depth and volume, as well as hydrologic parameters (i.e., tide height, tidal prism volume, freshwater inflow rates, salinity, and temperature). The ability of an estuary to dilute or flush pollutants can be estimated using physical and hydrologic properties such as volume, bathymetry, freshwater inflow and tidal exchange rates which influence residence time and affect pollutant loading rates. Thus, physical and hydrologic characteristics can be used to estimate the susceptibility of estuaries to pollutant effects. This classification of estuaries can be used by natural resource managers to describe and inventory coastal systems, understand stressor impacts, predict which systems are most sensitive to stressors, and manage and protect coastal resources.

The ecological condition of Gulf of Mexico resources from Perdido Key to Port St. Joe, Florida, USA: part I. coastal beach resources

Using the approach established by EPA's Environmental Monitoring and Assessment Program (EMAP), a shoreline monitoring survey was conducted in August and September 1999, encompassing the Florida Panhandle from Perdido Key, Florida to Port St. Joe, Florida. The objective of this survey was to demonstrate the use of a probabilistic survey for monitoring and estimating the condition of swimmable beach areas. Thirty stations were sampled using a probabilistic sampling design. Hydrographic data were collected in addition to samples for water chemistry. Bacterial indicators, enterococci and fecal coliforms, were enumerated from the water according to the EPA Beaches Environmental Assessment Closure and Health (BEACH) Program and Florida state guidelines. Additional criteria for site condition included the presence or absence of primary and secondary dunes, anthropogenic debris and vegetation. Based on EMAP evaluation guidelines and Florida state criteria, a baseline assessment of the condition of the Gulf of Mexico beach resources surveyed is presented.

An SNF2 protein associated with nuclear RNA silencing and the spread of a silencing signal between cells in Arabidopsis

The silencing phenotype in Arabidopsis thaliana lines with an inverted repeat transgene under the control of a phloem-specific promoter was manifested in regions around veins due to a mobile signal of silencing. Genetic analysis implicates RNA-DEPENDENT RNA POLYMERASE2 (RDR2) and an RNA polymerase IVa subunit gene (NRPD1a) in the signaling mechanism. We also identified an SNF2 domain-containing protein (CLASSY1) that acts together with RDR2 and NRPD1a in the spread of transgene silencing and in the production of endogenous 24-nucleotide short interfering RNAs (siRNAs). Cytochemical analysis indicates that CLASSY1 may act in the nucleus with NRPD1a and RDR2 in the upstream part of RNA silencing pathways that generate a double-stranded RNA substrate for Dicer-like (DCL) nucleases. DCL3 and ARGONAUTE4 act in a downstream part of the pathway, leading to endogenous 24-nucleotide siRNA production, but are not required for intercellular signaling. From genetic analysis, we conclude that another downstream part of the pathway associated with intercellular signaling requires DCL4 and at least one other protein required for 21-nucleotide trans-acting siRNAs. We interpret the effect of polymerase IVa and trans-acting siRNA pathway mutations in terms of a modular property of RNA silencing pathways.

Curve-fitting method for direct quantitation of compounds in complex biological mixtures using 1H NMR: application in metabonomic toxicology studies

A new software tool has been developed that provides automated measurement of signal intensities in NMR spectra of complex mixtures without using data reduction procedures. The algorithm finds best-fit transformations between signals in reference compound spectra and the corresponding signals in analyte spectra. Unlike other algorithms, it is insensitive to variation in chemical shift and can even be used for relative quantitation of compounds whose identities have not yet been established. Additionally, the parameters of the transformation provide information and error metrics that may assist in the streamlining of quality control. The approach presented is general in scope but has been tested by application to peak quantitation in NMR spectra of biofluids. Replicate NMR measurements of solutions of biologically important compounds at various concentrations were made. Further NMR data were collected on urine samples from human, rat, and mouse, which were "spiked" with reference compound solutions at known concentrations. Finally, existing data from an independent toxicology project involving several hundred samples were analyzed, and the consistency of the measurements for metabolites that give multiple NMR signals was assessed. The results of all these tests give confidence that the technique can be used in automated quantitation of compounds in large NMR data sets with minimal operator intervention.

Hypothalamic-pituitary-adrenal axis function in dissociative disorders, post-traumatic stress disorder, and healthy volunteers

BACKGROUND

This study investigated basal and stress-induced hypothalamic-pituitary-adrenal (HPA)-axis alterations in dissociative disorders (DDs).

METHODS

Forty-six subjects with DD without lifetime post-traumatic stress disorder (PTSD), 35 subjects with PTSD, and 58 healthy comparison (HC) subjects, free of current major depression, were studied as inpatients. After a 24-hour urine collection and hourly blood sampling for ambient cortisol determination, a low-dose dexamethasone suppression test was administered, followed by the Trier Social Stress Test.

RESULTS

The DD group had significantly elevated urinary cortisol compared with the HC group, which was more pronounced in the absence of lifetime major depression, whereas the PTSD and HC groups did not differ. The DD group demonstrated significantly greater resistance to, and faster escape from, dexamethasone suppression compared with the HC group, whereas the PTSD and HC groups did not differ. The three groups did not differ in cortisol stress reactivity, but both psychiatric groups demonstrated a significant inverse correlation between dissociation severity and cortisol reactivity, after controlling for all other symptomatology. The PTSD subgroup with comorbid DD tended to have blunted stress reactivity compared with the HC group.

CONCLUSIONS

The study demonstrates a distinct pattern of HPA-axis dysregulation in DDs, emphasizing the importance of further study of stress-response systems in dissociative psychopathology.

The ecological condition of Gulf of Mexico resources from Perdido Key to Port St. Joe, Florida: Part II near-shelf coastal resources

In 1999, the United States Environmental Protection Agency Gulf Ecology Division initiated a pilot study to assess the condition of nearshore coastal resources. Near-shelf areas associated with coastal beaches are susceptible to land based activities, but are not consistently monitored. Additionally, few or no marine water quality criteria exist for evaluating these waters. The goal of this pilot study was to assess the ecological condition of Gulf of Mexico near-shelf resources using a probability-based survey design. Data are used to generate a baseline assessment of condition in coastal nearshore areas and provide a comparative tool for evaluating future trends in condition. Water quality, sediment quality and benthic diversity data can provide a baseline assessment for managers to evaluate the potential for future problems such as nutrient over-enrichment, sediment contamination and degraded biological condition. We present results from a probability-based survey demonstration assessing near-shelf resources along the Florida panhandle.

Factors affecting survival of bacteriophage on tomato leaf surfaces

The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors.

Three sequential chemotherapy doublets for the treatment of newly diagnosed advanced müllerian malignancies: The modified triple doublet regimen

OBJECTIVE

Previously, we reported the use of three sequential doublets (Triple Doublets) in the treatment of women with newly diagnosed and advanced stage müllerian malignancies. The surgically defined negative second look operation (SLO) rate to Triple Doublets was 38%. Modifications were made to this treatment regimen that were predicted to reduce toxicity and possibly increase efficacy.

METHODS

Open label two-cohort study. Patients with a new diagnosis of Stages II-IV müllerian malignancy were eligible. After cytoreductive surgery, patients were treated with three sequential doublets including 3 cycles of carboplatin and gemcitabine, and 3 cycles of carboplatin and paclitaxel, and 3 cycles of doxorubicin and topotecan. After therapy, all women were clinically staged and evaluated at SLO if clinical staging was negative for residual disease. Primary endpoints were toxicity and negative SLO rate with rates of 60% and 40% defined a priori in optimally cytoreduced (cohort 1) and suboptimally cytoreduced or Stage IV (cohort 2), respectively.

RESULTS

Eighty-five eligible patients were enrolled with a median age of 52 years. Forty-seven and thirty-eight women were in cohorts 1 and 2, respectively. 723 cycles of chemotherapy were delivered with no toxic deaths. Grades 3 and 4 toxicities included neutropenia in 75% of patients and thrombocytopenia in 65% of patients during at least one cycle of therapy. Fever and neutropenia were seen in 3.5% of patients. All Grades 3 and 4 non-hematologic toxicities were seen at a frequency of <10%. Seventy women underwent SLO with a negative SLO rate of 53% with an additional 9% having microscopically positive procedures. Negative SLO rate was 74% in cohort 1 and 36% in cohort 2.

CONCLUSIONS

Treatment with the modified triple doublet regimen is tolerable with an encouraging pathologic CR rate.

Patients with grade 3 follicular lymphoma have prolonged relapse-free survival following anthracycline-based chemotherapy: the Nebraska Lymphoma Study Group Experience

BACKGROUND

The aim of the study was to determine the outcome and clinical features predictive of survival in patients with follicular lymphoma (FL) treated aggressively and to determine the rate of disease-specific mortality in patients with grade 3 FL (FL3).

MATERIALS AND METHODS

Four hundred and twenty-one patients with FL who were treated with various anthracycline-based chemotherapy regimens were included in this retrospective study.

RESULTS

Patients with FL3 and a diffuse component of >50% had the worst outcome, with a hazard ratio of dying of 2.2 (95% CI 1.4-3.4) compared with patients with FL1 or FL2, and a ratio of 1.6 (95% CI 1.02-2.5) compared with FL3 with a diffuse component of < or =50% by multivariate analysis (P = 0.0026). Patients with FL3a had an outcome similar to those with FL3b. In patients with FL3 and a diffuse component of < or =50%, the overall and event-free survival curves showed a plateau for patients younger than 60 years of age. However, there were no differences in the cumulative incidence of relapse/progression or lymphoma-specific/treatment-related mortality between the two age groups.

CONCLUSIONS

Less than half of the patients with FL3 and a diffuse component of < or =50% treated with anthracycline-based combination chemotherapy will relapse and relapses are uncommon after 6 years. Older patients should be offered the same aggressive chemotherapy as younger patients.

Assessing water clarity as a component of water quality in Gulf of Mexico estuaries

The U.S. Environmental Protection Agency Environmental Monitoring and Assessment Program (EMAP) uses water clarity as a water quality indicator for integrated assessments of coastal waters. After the publication of the first National Coastal Condition Report (USEPA, 2001c), the national water clarity reference value of 10% of ambient surface light at 1 m depth was reevaluated and modified to reflect expected differences in regional reference light conditions. These regional differences range from naturally turbid estuaries like those found in Mississippi and Louisiana to clear water estuaries expected to support extensive beds of submerged aquatic vegetation in, e.g., Florida and Tampa Bays. For the second National Coastal Condition Report, water clarity was assessed based on regional reference values (USEPA, 2004). Different regional water clarity reference values and data collection methods necessitated the development of a water clarity index based on light attenuation coefficients (k). This index incorporates regional reference conditions and is interchangeable with secchi depth and percent light transmission calculated from light meter measurements. Evaluation of the water clarity index shows that k values based on transmissivity at 1 m can be estimated from secchi depth measurements and successfully used as a surrogate for transmissivity calculated from light meter data. An approach for assessing water clarity in Gulf of Mexico estuaries using light meter data and secchi depth is presented.

The novel poly(ADP-Ribose) polymerase inhibitor, AG14361, sensitizes cells to topoisomerase I poisons by increasing the persistence of DNA strand breaks

Poly(ADP-ribose) polymerase (PARP) inhibitors enhance DNA topoisomerase I (topo I) poison-induced cytotoxicity and antitumor activity in vitro and in vivo, but the mechanism has not been defined. We investigated the role of PARP-1 in the response to topo I poisons using PARP-1-/- and PARP-1+/+ mouse embryonic fibroblasts and the potent PARP-1 inhibitor, AG14361 (Ki < 5 nmol/L). PARP-1-/- mouse embryonic fibroblasts were 3-fold more sensitive to topotecan than PARP-1+/+ mouse embryonic fibroblasts (GI50, 21 and 65 nmol/L, respectively). AG14361 caused a >3-fold sensitization of PARP-1+/+ cells to topotecan compared with a <1.4-fold sensitization in PARP-1-/- cells. In human leukemia K562 cells, AG14361 caused a 2-fold sensitization to camptothecin-induced cytotoxicity. AG14361 did not affect the cellular activity of topo I as determined by measurement of cleavable complexes and topo I relaxation activity, showing that sensitization was not due to topo I activation. In contrast, repair of DNA following camptothecin removal, normally very rapid, was significantly retarded by AG14361, resulting in a 62% inhibition of repair 10 minutes after camptothecin removal. This led to a 20% increase in the net accumulation of camptothecin-induced DNA strand break levels in cells coexposed to AG14361 for 16 hours. We investigated the DNA repair mechanism involved using a panel of DNA repair-deficient Chinese hamster ovary cells. AG14361 significantly potentiated camptothecin-mediated cytotoxicity in all cells, except the base excision repair-deficient EM9 cells. Therefore, the most likely mechanism for the potentiation of topo I poison-mediated cytotoxicity by AG14361 is via PARP-1-dependent base excision repair.

Species-specificity of a murine immunocontraceptive utilising murine cytomegalovirus as a gene delivery vector

Cytomegaloviruses are species-specific DNA viruses. Recombinant murine cytomegaloviruse (MCMV) expressing the mouse egg-coat protein zona pellucida 3 (mZP3) has been shown to sterilise female mice by breaking self-tolerance and inducing an immune response against the host ZP3. This virus has the potential to be used for mouse population control, however the effect of this recombinant immunocontraceptive virus in non-host species must be determined. Recombinant MCMV-mZP3, based on both laboratory and wild strains of virus, induced long-lived antibody responses against structural viral proteins and mZP3 when inoculated into laboratory rats, although no viral DNA or replicating virus was identified. The anti-mZP3 antibodies were specific for mouse ZP3, did not cross-react with rat ZP3, and had no effect on the fertility of the rats.

Metacercariae of Clinostomum attenuatum in Ambystoma tigrinum mavortium, Bufo cognatus and Spea multiplicata from west Texas

Tissues from barred tiger salamanders (Ambystoma tigrinum mavortium), Great Plains toads (Bufo cognatus) and New Mexico spadefoots (Spea multiplicata) collected from 16 playa wetlands in Texas during 1999 and 2000 were examined by light microscopy. Digenean cysts were primarily distributed subcutaneously throughout the specimens and occasionally coelomic invasion was noted. The parasites within the cysts were 1.5-2 mm in diameter, with a thin (c. 10 microm wide) eosinophilic-staining tegument, two suckers (oral and ventral), posteriorly located primordial genitalia and paired digestive caeca. These digeneans were identified as the metacercariae of Clinostomum attenuatum. This is the first record of Clinostomum attenuatum in these amphibian species.

Respiratory symptoms and airway obstruction in swine veterinarians: a persistent problem

OBJECTIVE

There are many occupational hazards associated with the practice of swine veterinarians. To reassess the prevalence of respiratory complaints and pulmonary function abnormalities in this group.

METHODS

This was a cross-sectional study conducted during the American Association of Swine Veterinarians annual meeting. Subjects completed a respiratory symptom/work history questionnaire and performed spirometry.

RESULTS

Participants included 122 veterinarians (median age=42.5 years). Work-related symptoms included rhinitis symptoms (69%), cough and chest tightness (53%), wheezing (31%). Airway obstruction was seen in 24% of participants. Veterinarians with airway obstruction reported working more hours per week in hog barns than did practitioners with normal pulmonary function (P=0.009).

CONCLUSIONS

Respiratory symptoms were common in the swine veterinarians tested as was airway obstruction. The association with these findings and hog barn exposure suggests that working in these facilities is still a risk factor for airway disease.

Isolates of cytomegalovirus (CMV) from the black rat Rattus rattus form a distinct group of rat CMV

Two different betaherpesviruses, the English and Maastricht species of rat cytomegalovirus (CMV), have previously been isolated from Rattus norvegicus. CMVs were isolated from both the brown rat, R. norvegicus, and the black rat, R. rattus, within Australia. The viruses isolated from R. norvegicus appeared to be genetically related to the English species of rat CMV by PCR, RFLP, and sequencing, but the viruses isolated from R. rattus were distinct from both prototype virus species, although more closely genetically related to the Maastricht virus. This is the first genetic characterization of cytomegaloviruses from R. rattus, and the first isolation of CMVs from Australian rats.

Collecting, archiving and processing DNA from wildlife samples using FTA databasing paper

Background

Methods involving the analysis of nucleic acids have become widespread in the fields of traditional biology and ecology, however the storage and transport of samples collected in the field to the laboratory in such a manner to allow purification of intact nucleic acids can prove problematical.

Results

FTA^® databasing paper is widely used in human forensic analysis for the storage of biological samples and for purification of nucleic acids. The possible uses of FTA^® databasing paper in the purification of DNA from samples of wildlife origin were examined, with particular reference to problems expected due to the nature of samples of wildlife origin. The processing of blood and tissue samples, the possibility of excess DNA in blood samples due to nucleated erythrocytes, and the analysis of degraded samples were all examined, as was the question of long term storage of blood samples on FTA^® paper. Examples of the end use of the purified DNA are given for all protocols and the rationale behind the processing procedures is also explained to allow the end user to adjust the protocols as required.

Conclusions

FTA^® paper is eminently suitable for collection of, and purification of nucleic acids from, biological samples from a wide range of wildlife species. This technology makes the collection and storage of such samples much simpler.

Formation of involatile methylantimony species by Clostridium spp

Trimethylantimony was detected by gas chromatography-mass spectrometry (GC-MS) in the headspace of a soil enrichment culture designed to promote growth of clostridia. Clostridial isolates from the soil enrichment culture were shown to biomethylate inorganic antimony in monseptic culture, using hydride generation-gas chromatographyatomic absorption spectrometry (HG-GC-AAS). GC-MS profiles of headspace gases from soil enrichment cultures shown to generate trimethylantimony, were used to select characterised Clostridium spp for assessment of antimony biomethylation capability. Involatile methylantimony species (up to 21 microg Sb dm(-3)) were detected by HG-GC-AAS in the medium of monoseptic cultures of C. acetobutylicum, C. butyricum and C. cochlearium. The relative quantities of involatile mono-, di- and trimethylantimony species produced over the course of a 28-day cultivation period is consistent with trimethylantimony oxide being a final product of antimony biomethylation by these bacteria, with mono- and dimethylantimony species appearing transiently in the cultures as intermediates of an antimony biomethylation pathway. Clostridia may be the principal agents of antimony biomethylation in methanogenic environments and could give rise to methylated forms of antimony in both the aqueous and gaseous phases.

A DNA computing readout operation based on structure-specific cleavage

We describe a structure-specific cleavage-based READOUT strategy for surface-based DNA computing. The strategy was demonstrated in the solution of a 4-variable/3-satisfiability (SAT) problem. The READOUT step identifies the DNA molecules present at the end of the computational process. The specificity of the sequence detection used here derives from the sequence specificity of DNA hybridization coupled with the structure specificity of the enzymatic cleavage. The process is linear, yielding a higher uniformity of detection of the DNA computing products compared to that obtained with PCR amplification. The structure-specific cleavage-based readout is simple, accurate, and compatible with multiple-word DNA computing.

Cytogenetic-clinicopathologic correlations in rhabdomyosarcoma: a report of five cases

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children younger than the age of 15 years. Histologically, RMS can be subdivided into two major subtypes; embryonal (E-RMS) and alveolar (A-RMS) rhabdomyosarcoma, with E-RMS being the more common. Although cytogenetic and molecular genetic findings have been reported extensively for RMS, clinicopathologic-genetic correlations among these tumors have not been reported in detail. In this report, we correlate the cytogenetic findings, including fluorescence in situ hybridization and spectral karyotyping, with pathologic findings and outcome for five RMS, including two A-RMS, one E-RMS, one botryoid RMS, and one anaplastic nonclassified RMS (N-RMS). The findings in A-RMS and E-RMS generally were consistent with previous reports; however, gain of chromosome 7 in A-RMS and gain of chromosome 9 segments in E-RMS observed here have seldom been reported in the literature. Importantly, the botryoid RMS had a cytogenetic profile similar to other types of E-RMS. An add(11)(q21) observed in this tumor, together with a t(8;11)(q12 approximately 13;q21) reported previously, indicates that 11q21 rearrangements may be nonrandomly related to botryoid RMS. In addition, the N-RMS expressed a cytogenetic pattern similar to that observed in E-RMS, thus providing genetic evidence that anaplastic N-RMS is a variant of E-RMS. Finally, these cases provide cogent evidence for the diagnostic and prognostic significance of the pathologic-genetic classification of RMS.

Which patients with microscopic disease and rhabdomyosarcoma experience relapse after therapy? A report from the soft tissue sarcoma committee of the children's oncology group

PURPOSE

To identify which patients with rhabdomyosarcoma and microscopic residual disease (group II) are likely to not respond to therapy.

PATIENTS AND METHODS

Six hundred ninety-five patients with group II tumors received chemotherapy and 90% received radiation therapy on Intergroup Rhabdomyosarcoma Study (IRS)-I to IRS-IV (1972 to 1997). Tumors were subgrouped depending on the presence of microscopic residual disease only (subgroup IIa), resected positive regional lymph nodes, (subgroup IIb), or microscopic residual disease and resected positive regional lymph nodes (subgroup IIc).

RESULTS

Overall, the 5-year failure-free survival rate (FFSR) was 73%, and patients with embryonal rhabdomyosarcoma treated on IRS-IV fared especially well (5-year FFSR, 93%; n = 90). Five-year FFSRs differed significantly by subgroup (IIa, 75% and n = 506; IIb, 74% and n = 101; IIc, 58% and n = 88; P = .0037) and treatment (IRS-I, 68%; IRS-II, 67%; IRS-III, 75%; IRS-IV, 87%; P < .001). Multivariate analysis revealed positive associations between primary site (favorable), histology (embryonal), subgroup IIa or IIb, treatment (IRS-III/IV), and better FFSRs. Patterns of treatment failure revealed local failure to be 8%, regional failure, 4%, and distant failure, 14%. The relapse pattern noted over the course of IRS-I to IRS-IV shows a decrease in the systemic relapse rates, particularly for patients with embryonal histology, suggesting that improvement in FFSRs is primarily a result of improved chemotherapy.

CONCLUSION

Group II rhabdomyosarcoma has an excellent prognosis with contemporary therapy as used in IRS-III/IV, and those less likely to respond can be identified using prognostic factors: histology, subgroup, and primary site. Patients with embryonal rhabdomyosarcoma are generally cured, although patients with alveolar rhabdomyosarcoma or undifferentiated sarcoma, particularly subgroup IIc at unfavorable sites, continue to need better therapy.

Analysis of single nucleotide polymorphisms with solid phase invasive cleavage reactions

Using microparticles as the capture surface and fluorescence resonance energy transfer as the detection technology, we have demonstrated the feasibility of performing the invasive cleavage reaction on a solid phase. An effective tool for many genomic applications, the solution phase invasive cleavage assay is a signal amplification method capable of distinguishing nucleic acids that differ by only a single base mutation. The method positions two overlapping oligonucleotides, the probe and upstream oligonucleotides, on the target nucleic acid to create a complex recognized and cleaved by a structure-specific 5'-nuclease. For microarray and other multiplex applications, however, the method must be adapted to a solid phase platform. Effective cleavage of the probe oligonucleotide occurred when either of the two required overlapping oligonucleotides was configured as the particle-bound reagent and also when both oligonucleotides were attached to the solid phase. Positioning probe oligonucleotides away from the particle surface via long tethers improved both the signal and the reaction rates. The particle-based invasive cleavage reaction was capable of distinguishing the ApoE Cys158 and Arg158 alleles at target concentrations as low as 100 amol/assay (0.5 pM).

Brain proton magnetic resonance spectroscopy in children exposed to methamphetamine in utero

OBJECTIVE

To examine the possible neurotoxic effects of prenatal methamphetamine exposure on the developing brain using 1H-MRS.

METHODS

Methamphetamine-exposed children (n = 12) and age-matched unexposed control subjects (n = 14) were evaluated with MRI, localized 1H-MRS, and a Child Behavior Checklist. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of visible structural abnormalities in either group, children exposed to methamphetamine in utero had higher [Cr] (+10%, p = 0.02) in the striatum. [NA], primarily a measure of N-acetylaspartate, was normal in both regions, which suggests no significant neuronal loss or damage in the two brain regions examined. There were no differences in reported behavior problems among the methamphetamine-exposed children relative to the unexposed group.

CONCLUSIONS

The authors found increased [Cr] in the striatum with relatively normal [NA] in children exposed to methamphetamine. These findings suggest an abnormality in energy metabolism in the brains of children exposed to methamphetamine in utero.

Exogenous interleukin-12 (IL-12) exacerbates Cryptosporidium parvum infection in gamma interferon knockout mice

Experimental infection of BALB/c- or C57BL/6-gamma-interferon-knockout (GKO) mice with Cryptosporidium parvum results in infection in both strains with different outcomes of disease. The BALB/c-GKO mice recover from infection, whereas the C57BL/6-GKO mice succumb to infection in less than 2 weeks. Differences in cytokine mRNA expression suggested that recovery may involve other cytokines. To determine whether the addition of either a Th1 or Th2 cytokine could alter the outcome of infection, we treated GKO mice with either recombinant (r)IL-4 or rIL-12 1 day before infection (DBI) or daily. No effect on the oocyst shedding patterns in either strain nor an increase in survival of the C57BL/6-GKO mice was observed in the rIL-4-treated mice. Whereas one dose of 0.5 microg rIL-12 given 1 DBI had no effect on oocyst shedding, we found that daily doses of rIL-12 administered intraperitoneally exacerbated C. parvum infection in both animal models. Administration of rIL-12 shortened the survival time in the C57BL/6-GKO mice and prevented BALB/c-GKO mice from recovering from infection. Specific proliferation of T cells to cryptosporidial antigen and Th1 and Th2 mRNA cytokine expression was markedly decreased in rIL-12-treated mice. Nitric oxide (NO) may have played a minor role in the decreased proliferation observed since levels of NO present in the splenocyte cultures from rIL-12-treated mice in response to parasite antigen stimulation were higher than those observed in controls. Thus, we propose that resistance to and recovery from C. parvum infections involves a fine balance in the amount and timing of Th1 and Th2 cytokines.

Species identity: conserved inverted LINE repeat clusters (ILRC) in the vertebrate genome as indicators of population boundaries

The avian LINE CR1 generates multiply-superimposed insertions, resulting in apparently fortuitous inverted LINE repeat clusters (ILRCs). These loci display size micro-heterogeneity within populations, with few or no presence/absence polymorphisms, and yet only very closely related species share loci. Whilst the CR1 sequences that the ILRC loci are derived from are not species-specific, the loci themselves appear to be species-characteristic if not totally species specific. The mammalian LINE L1 is shown to act similarly to CR1 and also forms ILRCs. It is proposed that whilst the formation of these loci may be from a near-random process of super-insertion certain of them are in some way functional, explaining their conservation and rapid spread to population boundaries, whilst non-functional or inactive loci are quickly lost. ILRCs appear to decay from the element as formed by the accumulation of point mutations. ILRCs appear to an unusual example of non-polymorphic sequences being younger than polymorphic sequences with no obvious selective reason.

Human T and B cell immunoreactivity to a recombinant 23-kDa Cryptosporidium parvum antigen

Cryptosporidial infection in humans results in parasite-specific IgG, IgM, and IgA antibody responses, but little is known of the cell-mediated immune responses to cryptosporidial antigens. In a convenience sample of 35 Haitian residents, there was a high level of cryptosporidial exposure (>90%) as determined by immunoblot reactivity of serum against cryptosporidial antigens. An attempt was made to determine if there was a relationship between antibody and T cell-mediated responses to recombinant Cp23 antigen and how this correlated with reactivity to crude sporozoite antigen preparations (SAg). T cell reactivity was greater against SAg (57%) than to Cp23 (34.3%) as measured by [3H]thymidine incorporation. Proliferative responses to Cp23 were significantly correlated with SAg responses. By enzyme-linked immunosorbent assay, most persons had IgG responses to both SAg (91.4%) and to recombinant Cp23 (88.5%). Antibody responses were greater among persons who exhibited T cell responses to SAg and Cp23. This study demonstrates that recombinant Cp23 antigen could be a useful antigen for detection of both antibody and cell-mediated responses in epidemiologic studies.

The role of p27 in endometrial carcinoma

OBJECTIVE

The cyclin-dependent kinase inhibitor p27 has been shown to mediate cell growth arrest in response to various environmental stimuli. p27 protein levels have shown prognostic value in several different types of cancer. We examined the prognostic value of p27 protein expression in endometrial cancer, the most common gynecologic malignancy.

METHODS

A total of 95 paraffin-embedded tumor blocks were obtained and stained via immunohistochemical techniques with a monoclonal antibody against p27. Ten high-power fields were evaluated per slide with at least 1000 cells per slide and two slides per specimen evaluated by two reviewers for nuclear and cytoplasmic staining. The specimens were evaluated for associations with age, stage, grade, and histology. Statistical analysis was performed using the Student t test, chi(2) Kaplan-Meier, and likelihood ratios to assess the data and to generate P values.

RESULTS

A total of 91 patients met inclusion criteria for statistical analysis. Fifty-three patients were stage I, 13 stage II, 14 stage III and 11 stage IV with a positive stain (>50% of cells) for p27 obtained in 32.1, 23.1, 35.7, and 36.4%, respectively (Student t test P = 0.77). Survival data were available on 24 advanced stage patients. p27 protein immunostaining showed no association with patient survival. We also found no association of p27 staining with age or histology. Notably, we found a trend in increasing staining with increase in grade, particularly with stage I patients. Also, there was an association of the nuclear and cytoplasmic staining and stage (P = 0.05), but it had no correlation with patient survival.

CONCLUSION

Our study showed decreased p27 protein staining in endometrial cancers compared to normal endometrial cells. We found that p27 protein staining shows no association with stage, age, or histology and is not prognostic for survival in advanced endometrial cancers. However, there may be a trend associated with increased p27 protein staining with advanced grades of tumors.

Renal responses to angiotensin II receptor blockade in ventilated preterm newborn lambs

Renal and cardiovascular immaturity has been linked with poor outcomes in the premature human newborn. Despite extensive study in the fetus, the contribution of the renin-angiotensin system to renal and cardiovascular function in the premature newborn has not been well characterized. To evaluate the angiotensin II contribution to preterm newborn renal and cardiovascular functions, preterm (120-day) and near-term (136-day) lambs were Caesarean delivered and ventilated. One hour following delivery, animals were randomized to receive angiotensin II receptor-blockade (saralasin; 20 microg kg(-1) min(-1)) or saline (CON). Prior to blockade, mean +/- SEM values for urine flow (U(Flow)), urinary sodium excretion (U(NaV)), and fractional excretion of sodium (FENa) were similar in all groups. Angiotensin II receptor-blockade decreased U(Flow), U(NaV) and FENa in the 120-day group with no changes in the 136-day animals. No changes in mean arterial pressure, or plasma angiotensin II, aldosterone, and renin activity levels were noted at either gestational age.

CONCLUSIONS

(1) angiotensin II contributes to the regulation of renal function in 120-day preterm lambs without changing blood pressure and (2) angiotensin II-mediated feedback inhibition of renin release is uncoupled in preterm newborns.

Brain proton magnetic resonance spectroscopy and imaging in children exposed to cocaine in utero

OBJECTIVE

The effects of prenatal cocaine exposure have been examined using neurobehavioral and brain structural evaluations; however, no study has examined the effects of prenatal cocaine on brain metabolism. Proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive method to examine the biochemistry of various brain regions. The purpose of this study was to examine the possible neurotoxic effects of prenatal cocaine exposure on the developing brain using (1)H-MRS.

METHODS

Cocaine-exposed children (n = 14) and age-matched unexposed control participants (n = 12) were evaluated with MRI and localized (1)H-MRS. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of structural abnormalities in either group, children exposed to cocaine in utero had significantly higher Cr (+13%) in the frontal white matter. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal in both regions examined by (1)H-MRS. Normal NA suggests no significant neuronal loss or damage in the 2 brain regions examined in children exposed to cocaine prenatally.

CONCLUSIONS

Consistent with findings in abstinent adult cocaine users, we found increased Cr in the frontal white matter, with normal NA in children exposed to cocaine. These findings suggest the need to investigate further possible abnormalities of energy metabolism in the brain of children exposed to cocaine in utero. In addition, this study demonstrates the feasibility of using (1)H-MRS to investigate the effects of prenatal drug exposure on the developing brain.

Breast cancer after mantle irradiation for Hodgkin's disease: correlation of clinical, pathologic, and molecular features including loss of heterozygosity at BRCA1 and BRCA2

PURPOSE

Hodgkin's disease patients who receive mantle irradiation have an age-dependent increased risk of developing breast cancer. To determine if genetic factors predispose these patients to develop breast cancer, we evaluated breast cancer specimens for loss of heterozygosity (LOH) at regions where BRCA1 and BRCA2, two breast cancer tumor suppressor genes, are located. We also evaluated whether breast cancers in patients who were previously treated with radiation have a more aggressive phenotype, and whether the clinical course differed from a sporadic group of breast cancer patients.

METHODS AND MATERIALS

All females with Hodgkin's disease who were subsequently diagnosed with breast cancer and for whom tissue blocks were available were included. Using a case-control design, case patients (previously treated with radiation therapy) were matched with sporadic control breast cancer patients for age, breast cancer stage, and date of breast cancer diagnosis. After microdissection of tumor and normal tissue from paraffin-embedded tissue blocks, DNA was extracted and samples were examined for LOH at chromosomal segments encompassing BRCA1 and BRCA2. Breast cancer specimens were also evaluated in a blinded fashion for tumor grade and immunoreactivity to estrogen and progesterone receptors, p53, her2-neu, and topoisomerase II alpha. Comparisons were made between the case and control populations using chi2 analysis, and a paired Student's t test. Survival differences were evaluated using a log-rank test.

RESULTS

From January 1960 to December 1983, 917 patients were diagnosed with Hodgkin's disease. Twelve patients were subsequently diagnosed with breast cancer and tissue blocks were available on 10 cases. No statistical difference was observed between the case and control populations for LOH at BRCA1 or BRCA2. In the Hodgkin's disease group, LOH was observed in 30% of tumors at BRCA1 and 10% of tumors at BRCA2 vs. 10% and 0% of tumors in the control group at BRCA1 and BRCA2, respectively. Breast tumors from patients who received radiation therapy for Hodgkin's disease displayed greater nuclear pleomorphism (p < 0.02), and an increase in topoisomerase II alpha expression (p < 0.05) vs. the control population. Five of 10 patients were pregnant at the time of their Hodgkin's treatment, and those patients had a shorter time interval to the development of breast cancer compared with the patients who were not pregnant (12.4 years compared with 18.6 years). There was no significant difference in disease-free survival; however, overall survival was inferior in the population previously treated with radiation therapy for Hodgkin's disease (p = 0.01). 80% of patients with a previous Hodgkin's diagnosis died of breast cancer or treatment related effects vs. 30% in the control group.

CONCLUSION

We were unable to find statistical evidence for LOH at BRCA1 and BRCA2 in breast cancers from patients previously irradiated for Hodgkin's disease. Breast cancer diagnosed after mantle irradiation may be more biologically aggressive based on the greater nuclear pleomorphism and increase in topoisomerase II alpha staining. This did not translate into a statistical difference in breast cancer disease-free survival; however, overall survival was significantly inferior in the Hodgkin's disease patients.