Reframing wildlife disease management problems with decision analysis

Contemporary wildlife disease management is complex because managers need to respond to a wide range of stakeholders, multiple uncertainties, and difficult trade-offs that characterize the interconnected challenges of today. Despite general acknowledgment of these complexities, managing wildlife disease tends to be framed as a scientific problem, in which the major challenge is lack of knowledge. The complex and multifactorial process of decision-making is collapsed into a scientific endeavor to reduce uncertainty. As a result, contemporary decision-making may be oversimplified, rely on simple heuristics, and fail to account for the broader legal, social, and economic context in which the decisions are made. Concurrently, scientific research on wildlife disease may be distant from this decision context, resulting in information that may not be directly relevant to the pertinent management questions. We propose reframing wildlife disease management challenges as decision problems and addressing them with decision analytical tools to divide the complex problems into more cognitively manageable elements. In particular, structured decision-making has the potential to improve the quality, rigor, and transparency of decisions about wildlife disease in a variety of systems. Examples of management of severe acute respiratory syndrome coronavirus 2, white-nose syndrome, avian influenza, and chytridiomycosis illustrate the most common impediments to decision-making, including competing objectives, risks, prediction uncertainty, and limited resources.

Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies

Human activity changes multiple factors in the environment, which can have positive or negative synergistic effects on organisms. However, few studies have explored the causal effects of multiple anthropogenic factors, such as urbanization and invasive species, on animals and the mechanisms that mediate these interactions. This study examines the influence of urbanization on the detrimental effect of invasive avian vampire flies (Philornis downsi) on endemic Darwin's finches in the Galápagos Islands. We experimentally manipulated nest fly abundance in urban and non-urban locations and then characterized nestling health, fledging success, diet, and gene expression patterns related to host defense. Fledging success of non-parasitized nestlings from urban (79%) and non-urban (75%) nests did not differ significantly. However, parasitized, non-urban nestlings lost more blood, and fewer nestlings survived (8%) compared to urban nestlings (50%). Stable isotopic values (δ15 N) from urban nestling feces were higher than those from non-urban nestlings, suggesting that urban nestlings are consuming more protein. δ15 N values correlated negatively with parasite abundance, which suggests that diet might influence host defenses (e.g., tolerance and resistance). Parasitized, urban nestlings differentially expressed genes within pathways associated with red blood cell production (tolerance) and pro-inflammatory response (innate immunological resistance), compared to parasitized, non-urban nestlings. In contrast, parasitized non-urban nestlings differentially expressed genes within pathways associated with immunoglobulin production (adaptive immunological resistance). Our results suggest that urban nestlings are investing more in pro-inflammatory responses to resist parasites but also recovering more blood cells to tolerate blood loss. Although non-urban nestlings are mounting an adaptive immune response, it is likely a last effort by the immune system rather than an effective defense against avian vampire flies since few nestlings survived.

Within-patch and edge microclimates vary over a growing season and are amplified during a heatwave: Consequences for ectothermic insects

Embedded in longer term warming are extreme climatic events such as heatwaves and droughts that are increasing in frequency, duration and intensity. Changes in climate attributes such as temperature are often measured over larger spatial scales, whereas environmental conditions to which many small ectothermic arthropods are exposed are largely determined by small-scale local conditions. Exposed edges of plant patches often exhibit significant short-term (daily) variation to abiotic factors due to wind exposure and sun radiation. By contrast, within plant patches, abiotic conditions are generally much more stable and thus less variable. Over an eight-week period in the summer of 2020, including an actual heatwave, we measured small-scale (1 m²) temperature variation in patches of forbs in experimental mesocosms. We found that soil surface temperatures at the edge of the mesocosms were more variable than those within mesocosms. Drought treatment two years earlier, amplified this effect but only at the edges of the mesocosms. Within a plant patch both at the soil surface and within the canopy, the temperature was always lower than the ambient air temperature. The temperature of the soil surface at the edge of a patch may exceed the ambient air temperature when ambient air temperatures rise above 23 °C. This effect progressively increased with ambient temperature. We discuss how microscale-variation in temperature may affect small ectotherms such as insects that have limited ability to thermoregulate, in particular under conditions of extreme heat.

Urban living influences the nesting success of Darwin's finches in the Galápagos Islands

Urbanization is expanding worldwide with major consequences for organisms. Anthropogenic factors can reduce the fitness of animals but may have benefits, such as consistent human food availability. Understanding anthropogenic trade-offs is critical in environments with variable levels of natural food availability, such as the Galápagos Islands, an area of rapid urbanization. For example, during dry years, the reproductive success of bird species, such as Darwin's finches, is low because reduced precipitation impacts food availability. Urban areas provide supplemental human food to finches, which could improve their reproductive success during years with low natural food availability. However, urban finches might face trade-offs, such as the incorporation of anthropogenic debris (e.g., string, plastic) into their nests, which may increase mortality. In our study, we determined the effect of urbanization on the nesting success of small ground finches (Geospiza fuliginosa; a species of Darwin's finch) during a dry year on San Cristóbal Island. We quantified nest building, egg laying and hatching, and fledging in an urban and nonurban area and characterized the anthropogenic debris in nests. We also documented mortalities including nest trash-related deaths and whether anthropogenic materials directly led to entanglement- or ingestion-related nest mortalities. Overall, urban finches built more nests, laid more eggs, and produced more fledglings than nonurban finches. However, every nest in the urban area contained anthropogenic material, which resulted in 18% nestling mortality while nonurban nests had no anthropogenic debris. Our study showed that urban living has trade-offs: urban birds have overall higher nesting success during a dry year than nonurban birds, but urban birds can suffer mortality from anthropogenic-related nest-materials. These results suggest that despite potential costs, finches benefit overall from urban living and urbanization may buffer the effects of limited resource availability in the Galápagos Islands.

Serum triamcinolone levels during intensive, inpatient wet-dressing therapy

BACKGROUND

Wet dressings combined with topical corticosteroids are beneficial for patients with generalized and refractory dermatosis; however, to our knowledge, serum levels after topical corticosteroid absorption during intensive therapy have not been reported previously.

AIM

To examine serum levels of triamcinolone acetonide (TAC) after topical corticosteroid application during intensive wet-dressing therapy.

METHODS

We performed a retrospective study of adult patients admitted for inpatient wet-dressing therapy from 7 November 2015 to 24 June 2016. Data were collected on sex, age, body surface area, TAC serum levels, number of wet-dressing changes after 24 and 48 h, and type of wet dressing.

RESULTS

In total, 29 patients (14 men, 15 women) were assessed. Median [interquartile range (IQR)] age was 57 years (51.5-67.0 years) and involved body surface area was 1.98 m² (1.88-2.15) m² . Before the 24-hour blood draw, patients had received 1-3 dressing changes. Median (IQR) TAC level at 24 h was 0.33 µg/dL (0.20-0.58 µg/dL), with no significant difference noted between the number of dressing changes and TAC serum level. At 48 h, results of a serum TAC test were available for 22 patients with 2-6 dressing changes. Mean (IQR) serum level was 0.30 µg/dL (0.30-0.87 µg/dL). For each additional dressing change, there was an estimated 0.21 µg/dL increase in TAC serum level (95% CI 0.11-0.31; P < 0.001). TAC serum level was not significantly associated with sex, age, body surface area or dressing type.

CONCLUSIONS

Intensive, inpatient wet-dressing therapy is associated with detectable TAC serum levels. However, we suspect that topical TAC has a primarily local therapeutic effect on the skin.

Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?

Species delimitation attempts to match species-level taxonomy with actual evolutionary lineages. Such taxonomic conclusions are typically, but not always, based on patterns of congruence across multiple data sources and methods of analyses. Here, we use this pluralistic approach to species delimitation to help resolve uncertainty in species boundaries of phrynosomatid sand lizards of the genus Holbrookia. Specifically, the Spot-tailed Earless Lizard (H. lacerata) was historically divided into a northern (H. l. lacerata) and southern (H. l. subcaudalis) subspecies based on differences in morphology and allopatry, but no research has been conducted evaluating genetic differences between these taxa. In this study, patterns in sequence data derived from two genes, one nuclear and one mitochondrial, for 66 individuals sampled across 18 counties in Texas revealed three strongly supported, reciprocally monophyletic lineages, each comprised of individuals from a single geographic region. Distinct genetic variation evident across two of these regions corresponds with differences in morphology, differences in environmental niche, and lines up with the presumed geographic barrier, the Balcones Escarpment, which is the historical subspecies boundary. The combined evidence from genetics, morphology and environmental niche is sufficient to consider these subspecies as distinct species with the lizards north of the Balcones Escarpment retaining the name Holbrookia lacerata, and those south of the Balcones Escarpment being designated as Holbrookia subcaudalis.

Avian haemosporidian detection across source materials: prevalence and genetic diversity

Avian haemosporidians make up one of the most widely distributed and diverse vector borne parasite systems, found nearly worldwide in tropical and temperate areas. Despite the clear relationship between avian host fitness measures and infection, few studies have addressed the importance of source material selection when assessing these relationships. We show that source material, here blood and pectoral muscle, do not yield equivalent results when assessing prevalence and genetic diversity of haemosporidian genera. We find higher prevalence and genetic diversity are recovered from blood versus pectoral muscle for Haemoproteus. Contrastingly, we find that a higher prevalence of Plasmodium is detected from pectoral muscle, while higher genetic diversity is recovered from blood. Our results indicate that source material may bias parasite detection and be an important factor in study design, which is not only related to parasite infection, but by extension to the ecology and fitness of avian hosts.

Habitat complexity reduces parasitoid foraging efficiency, but does not prevent orientation towards learned host plant odours

It is well known that many parasitic wasps use herbivore-induced plant odours (HIPVs) to locate their inconspicuous host insects, and are often able to distinguish between slight differences in plant odour composition. However, few studies have examined parasitoid foraging behaviour under (semi-)field conditions. In nature, food plants of parasitoid hosts are often embedded in non-host-plant assemblages that confer both structural and chemical complexity. By releasing both naïve and experienced Cotesia glomerata females in outdoor tents, we studied how natural vegetation surrounding Pieris brassicae-infested Sinapis arvensis and Barbarea vulgaris plants influences their foraging efficiency as well as their ability to specifically orient towards the HIPVs of the host plant species on which they previously had a positive oviposition experience. Natural background vegetation reduced the host-encounter rate of naïve C. glomerata females by 47 %. While associative learning of host plant HIPVs 1 day prior to foraging caused a 28 % increase in the overall foraging efficiency of C. glomerata, it did not reduce the negative influence of natural background vegetation. At the same time, however, females foraging in natural vegetation attacked more host patches on host-plant species on which they previously had a positive oviposition experience. We conclude that, even though the presence of natural vegetation reduces the foraging efficiency of C. glomerata, it does not prevent experienced female wasps from specifically orienting towards the host-plant species from which they had learned the HIPVs.

Children with autism spectrum disorders show abnormal conditioned response timing on delay, but not trace, eyeblink conditioning

Children with autism spectrum disorder (ASD) and age-matched typically-developing (TD) peers were tested on two forms of eyeblink conditioning (EBC), a Pavlovian associative learning paradigm where subjects learn to execute an appropriately-timed eyeblink in response to a previously neutral conditioning stimulus (CS). One version of the task, trace EBC, interposes a stimulus-free interval between the presentation of the CS and the unconditioned stimulus (US), a puff of air to the eye which causes the subjects to blink. In delay EBC, the CS overlaps in time with the delivery of the US, usually with both stimuli terminating simultaneously. ASD children performed normally during trace EBC, exhibiting no differences from TD subjects with regard to the learning rate or the timing of the conditioned response. However, when subsequently tested on delay EBC, subjects with ASD displayed abnormally-timed conditioned eye blinks that began earlier and peaked sooner than those of TD subjects, consistent with previous findings. The results suggest an impaired ability of children with ASD to properly time conditioned eye blinks which appears to be specific to delay EBC. We suggest that this deficit may reflect a dysfunction of the cerebellar cortex in which increases in the intensity or duration of sensory input can temporarily disrupt the accuracy of motor timing over short temporal intervals.

Quantification of various factors influencing the precision of thermoluminescent detector calibrations for new and used chip sets

Factors affecting the random and systematic error in calibrating three sets of 100 LiF:Mg,Ti thermoluminescent detector chips were investigated. The chips were held in a polymethyl methacrylate plate with 0.3 cm deep wells covered with a thin top plate, affixed to a polymethyl methacrylate phantom 150 cm from a 3.2 × 10(10) GBq 137Cs source, used to irradiate the chips to 4.52 mGy. Three sets of chips were used: one new, one heavily used, and one having relatively high degrees of visible physical damage. Variations in the exposure rate across the plate were measured with an ion chamber. Experimental drift was judged by performing successive calibrations on subsequent days, while always reading the chips in the same order. The chips were subject to manual examination to determine variations in mass and physical quality. This study indicates that more accurate calibrations can be obtained by accounting for the error caused by nonuniformity in the delivered dose, which was in this study as high as 4.4% from the center to the edges of the target. Making use of more than three calibrations only reduces the standard deviation as a percentage of the mean of a set by less than 1%. Desirable dosimeters in commercially rejected sets were identified by comparing each dosimeter's standard deviation of response across all calibrations to a commercially acceptable control set. Up to 50% variations in mass and visual quality, including opacity, fracture, and surface scratches to chips, showed little to no correlation with their response.

Anomalous fluctuations of s-wave reduced neutron widths of 192,194Pt resonances

We obtained an unprecedentedly large number of s-wave neutron widths through R-matrix analysis of neutron cross-section measurements on enriched Pt samples. Careful analysis of these data rejects the validity of the Porter-Thomas distribution with a statistical significance of at least 99.997%.

Salvage definitive chemo-radiotherapy for locally recurrent oesophageal carcinoma after primary surgery: retrospective review

To determine the overall survival and gastrointestinal toxicity for patients treated with salvage definitive chemo-radiotherapy after primary surgery for locoregional relapse of oesophageal carcinoma. A retrospective review of 525 patients who had a resection for oesophageal or oesophagogastric carcinoma at Princess Alexandra Hospital identified 14 patients treated with salvage definitive radiotherapy or chemo-radiotherapy, following localized recurrence of their disease. We analysed the patient and treatment characteristics to determine the median overall survival as the primary end point. Gastrointestinal toxicity was examined to determine if increased toxicity occurred when the stomach was irradiated within the intrathoracic radiotherapy field. The median overall survival for patients treated with curative intent using salvage definitive chemo-radiotherapy was 16 months and the 2-year overall survival is 21%. One patient is in clinical remission more than 5 years after therapy. Age <60 years old and nodal recurrence were favourable prognostic factors. Treatment compliance was 93% with only one patient unable to complete the intended schedule. Fourteen per cent of patients experienced grade 3 or 4 gastrointestinal toxicity. Salvage definitive chemo-radiotherapy should be considered for good performance status patients with oesophageal carcinoma who have a locoregional relapse after primary surgery. The schedule is tolerable with low toxicity and an acceptable median survival.

Current status of inverse agonism at serotonin2A (5-HT2A) and 5-HT2C receptors

Contemporary receptor theory was developed to account for the existence of constitutive activity, as defined by the presence of receptor signaling in the absence of any ligand. Thus, ligands acting at a constitutively active receptor, can act as agonists, antagonists, and inverse agonists. In vitro studies have also revealed the complexity of ligand/receptor interactions including agonist-directed stimulus trafficking, a finding that has led to multi-active state models of receptor function. Studies with a variety of cell types have established that the serotonin 5-HT(2A) and 5-HT(2C) receptors also demonstrate constitutive activity and inverse agonism. However, until recently, there has been no evidence to suggest that these receptors also demonstrate constitutive activity and hence reveal inverse agonist properties of ligands in vivo. This paper describes our current knowledge of constitutive activity in vitro and then examines the evidence for constitutive activity in vivo. Both the serotonin 5-HT(2A) and 5-HT(2C) receptors are involved in a number of physiological and behavioral functions and are the targets for treatment of schizophrenia, anxiety, weight control, Parkinsonism, and other disorders. The existence of constitutive activity at these receptors in vivo, along with the possibility of inverse agonism, provides new avenues for drug development.

Oviposition cues for a specialist butterfly--plant chemistry and size

The oviposition choice of an insect herbivore is based on a complex set of stimuli and responses. In this study, we examined the effect of plant secondary chemistry (the iridoid glycosides aucubin and catalpol) and aspects of size of the plant Plantago lanceolata, on the oviposition behavior of the specialist butterfly Melitaea cinxia. Iridoid glycosides are known to deter feeding or decrease the growth rate of generalist insect herbivores, but can act as oviposition cues and feeding stimulants for specialized herbivores. In a previous observational study of M. cinxia in the field, oviposition was associated with high levels of aucubin. However, this association could have been the cause (butterfly choice) or consequence (plant induction) of oviposition. We conducted a set of dual- and multiple-choice experiments in cages and in the field. In the cages, we found a positive association between the pre-oviposition level of aucubin and the number of ovipositions. The association reflects the butterfly oviposition selection rather than plant induction that follows oviposition. Our results also suggest a threshold concentration below which females do not distinguish between levels of iridoid glycosides. In the field, the size of the plant appeared to be a more important stimulus than iridoid glycoside content, with bigger plants receiving more oviposition than smaller plants, regardless of their secondary chemistry. Our results illustrate that the rank of a cue used for oviposition may be dependent on environmental context.

Positron emission tomography and pathological evidence of response to neoadjuvant therapy in adenocarcinoma of the esophagus

Our aim was to determine if fluorodeoxyglucose positron emission tomography (FDG-PET) could be correlated with a pathological response in patients with esophageal adenocarcinoma receiving neoadjuvant chemotherapy and/or chemoradiation therapy. Patients with resectable, histologically proven adenocarcinoma of the esophagus were entered in the study. Preoperative chemotherapy comprised two cycles of cisplatin and 5-fluorouracil. Radiation therapy commenced with the second cycle on day 22. FDG-PET images were obtained pre-treatment and on completion of intended neo-adjuvant treatment. Quantification was achieved by the calculation of both standardized uptake values (SUV) and tumor/liver ratios (TLR). Evidence of histopathological response was identified according to the Mandard tumor regression scoring system. There were 45 patients, 22 receiving neoadjuvant chemotherapy and 23 chemoradiation therapy. Forty patients underwent surgical resection. Seven patients (16%) had a histopathological response. The mean percentage change in SUV in the histological responders group was -56.8% (SD 29) and in the non-responders -27.8% (SD 32.1) (P = 0.035). The mean percentage change in TLR was -49.1% (SD 44.8) in the responders and in the non-responders -27.3% (SD 31.3) (P = 0.128). There was no difference between the two methods of assessment, however there was less variation with SUV. There was no correlation between the FDG-PET response and the histopathological response. Presently an FDG-PET scan performed 3-6 weeks after neoadjuvant therapy for adenocarcinoma of the esophagus should not be used as a marker of the potential result of the treatment. The optimal timing of a second FDG-PET remains unclear.

Outcomes from salvage esophagectomy post definitive chemoradiotherapy compared with resection following preoperative neoadjuvant chemoradiotherapy

Chemoradiotherapy (CRT) as a definitive treatment for esophageal cancer, is being used with increasing frequency and as a result, surgeons will be required to assess more patients who have residual or recurrent local malignancy. This article aimed to assess outcomes after esophagectomy following definitive CRT (dCRT) and compare any difference between them and patients who had preoperative neoadjuvant CRT (nCRT) using a similar regimen of chemotherapy. From a prospective database the details of patients who had a resection following nCRT and dCRT were analyzed. The main therapeutic difference between the groups was the dose of radiotherapy (35 vs 60 Gy) and the timing of the resection following completion of the CRT (median 4 vs 28 weeks). Fourteen patients had an esophagectomy following a dCRT and 53 had one following a nCRT. Preoperatively, the dCRT group had worse respiratory function and more ECG abnormalities. Preoperative tumor length, pathological TNM staging and R0 resection rates were the same in both groups. Post resection, the dCRT group had greater morbidity than the nCRT group, spending longer in the intensive care unit (median 48 vs 24 h), more days in hospital (median 31 vs 13) and having more severe respiratory complications (37%vs 6%). The operative mortality was higher in the dCRT group (7%vs 0%). The three-year survival was 24% after dCRT. Patients selected for salvage esophagectomy following dCRT are a major challenge in postoperative care. However, some patients survive for a reasonable period of time, making resection a worthwhile option.

Optimum and maximum host sizes at parasitism for the endoparasitoid Hyposoter didymator (Hymenoptera: Ichneumonidae) differ greatly between two host species

Host size is considered a reliable indicator of host quality and an important determinant of parasitoid fitness. Koinobiont parasitoids attack hosts that continue feeding and growing during parasitism. In contrast with hemolymph-feeding koinobionts, tissue-feeding koinobionts face not only a minimum host size for successful development but also a maximum host size, because consumption of the entire host is often necessary for successful egression. Here we study interactions between a generalist tissue-feeding larval endoparasitoid, Hyposoter didymator Thunberg (Hymenoptera: Ichneumonidae) and two of its natural hosts, Spodoptera exigua Hübner and Chrysodeixis chalcites Esper (Lepidoptera: Noctuidae). Larvae of C. chalcites are up to three times larger than corresponding instars of S. exigua and also attain much higher terminal masses before pupation. We hypothesized that the range of host instars suitable for successful parasitism by H. didymator would be much more restricted in the large host C. chalcites than in the smaller S. exigua. To test this hypothesis, we monitored development of H. didymator in all instars of both host species and measured survival, larval development time, and adult body mass of the parasitioid. In contrast with our predictions, C. chalcites was qualitatively superior to S. exigua in terms of the survival of parasitized hosts, the proportion of parasitoids able to complete development, and adult parasitoid size. However, in both hosts, the proportion of mature parasitoid larvae that successfully developed into adults was low at the largest host sizes. Our results suggest that qualitative, as well as quantitative, factors are important in the success of tissue-feeding parasitoids.

Cotesia kariyai larvae need an anchor to emerge from the host Pseudaletia separata

Mature larvae of the gregarious endoparasitoid Cotesia kariyai construct cocoons for pupation approximately 10 days after parasitization and emerge from their host Pseudaletia separata under a long day photo-regime (16L8D) at 25 +/- 1 degrees C. The parasitoid larvae make capsules in the host hemocoel just prior to their emergence. These capsules function as "anchors," which enable them to press against the host integument from inside the host. It was predicted that this anchor might be composed of silk proteins secreted from the parasitoid larvae, because a previous study showed that the anchor was made up of a glycoprotein and that the silk gland of parasitoid larvae developed from 2nd larval stage. Fibroin-like proteins in C. kariyai larva mainly consist of two proteins with molecular masses of the 300.6 and 46.7 kDa estimated by SDS-PAGE. The fibroin-like proteins with the same molecular mass were detected from the anchor proteins just prior to parasitoid emergence. These results indicate that the anchor was assembled with fibroin-like proteins and was formed just before parasitoid emergence while in the host body cavity. Injection of bovine pancreatic trypsin inhibited the emergence of parasitoid larvae from the host because the anchor was decomposed by trypsin. Trypsin activity in the parasitized host hemolymph increased only after parasitoid emergence.

Influence of nutrient deficiency caused by host developmental arrest on the growth and development of a koinobiont parasitoid

Koinobiont parasitoids utilize nutrients obtained from hosts that contine to feed and grow after parasitization. However, if the ecdysis of early host instars is prevented, parasitized larvae will fail to grow large enough to support the development of the parasitoid brood and both organisms will perish. When L5 instar larvae (the penultimate stage) of Pseudaletia separata were parasitized by Cotesia kariyai and injected with Euplectrus separatae venom (5PV), the development of these hosts was arrested before molting to the next stage and the caterpillars thus failed to gain weight. These hosts remained at approximately 300 mg until parasitoid emergence. In contrast, hosts parasitized as L5 but without the injection of venom (5P) exhibited an increase in weight after molting to the next stage and ultimately grew to approximately 700 mg. The inhibition of ecdysis reduced the amount of food resource (e.g. fat body) for the parasitoid larvae. On the other hand, when final (= L6) host instars were parasitized and injected with E. separatae venom (6PV), the maximum weight attained by these larvae was about 710 mg, although weight gain was depressed compared to hosts parasitized without the injection of E. separatae venom (6P). The adult weight of C. kariyai that emerged from 5PV hosts was less than conspecifics that emerged from 5P, 6P, and 6PV respectively, although the egg-pupal period of the parasitoid from 5PV hosts was extended. The offspring sex ratio (percentage males) of adult wasps did not vary significantly with treatment. Female parasitoids that eclosed from 5PV hosts laid almost the same number of eggs in day 0-6th host instars as those emerging from 5P, 6P, 6PV hosts. Their egg-pupal period was extended and the cocoon cluster mass and the parasitoid body mass on subsequent generations was lighter than those reared from 5P, 6P, 6PV hosts. The sex ratio of F2 C. kariyai wasps that eclosed from 5PV increased more than in wasps that eclosed from the other host treatments (5P, 6P, 6PV). Our results reveal that a reduction in host quality and offspring fitness in the first generation negatively impacted female fitness in the second generation. An early arrestment of host growth, mediated by the addition of E. separatae venom, has severe implications on parasitoid fitness by reducing host quality, especially in smaller hosts.

Effect of serotonin depletion on 5-HT2A-mediated learning in the rabbit: evidence for constitutive activity of the 5-HT2A receptor in vivo

RATIONALE

Associative learning during Pavlovian eyeblink conditioning has been shown to be regulated by 5-HT2A receptors. The existence of inverse agonists that retard learning through an action at the 5-HT2A receptor suggests the existence of constitutive activity at that receptor and that depletion of serotonin should have minimal effects on learning.

OBJECTIVES

We examined whether depletion of serotonin would impair trace eyeblink conditioning or the enhancement of conditioning produced by the agonist lysergic acid diethylamide (LSD) and the retardation of conditioning produced by the inverse agonist MDL11,939.

METHODS

Animals received bilateral intraventricular injections of 5,7-dihydroxytryptamine (5,7-DHT) at doses of 760 or 1,140 microg/side (1.88 or 2.82 micromol/side) and were later exposed to eight daily conditioning sessions.

RESULTS

Serotonin depletion produced by the lower dose of 5,7-DHT was 71 and 72% in cortex and hippocampus, respectively, with no change in 5-HT2A receptor density, no effect on learning, and no effect on the ability of LSD to enhance and MDL11,939 to retard learning. The higher dose of 5,7-DHT produced serotonin decreases of 85 and 90% in cortex and hippocampus, respectively, accompanied by a 96% decrease in the density of the serotonin transporter, but no significant effect on learning.

CONCLUSIONS

Pavlovian trace eyeblink conditioning is regulated predominantly by the constitutive activity of the 5-HT2A receptor rather than by serotonin release onto the receptor during learning. It was suggested that the 5-HT2A receptor regulates learning by modulating the release of dopamine, acetylcholine, and glutamate, transmitters known to affect eyeblink conditioning.

Neutron cross section measurements at ORELA for improved nuclear data and their application

To support the Nuclear Criticality Safety Program, the Oak Ridge Electron Linear Accelerator (ORELA) has been used to measure the total and capture neutron cross sections of several nuclides in the energy range from 100 eV to -600 keV. Concerns about the use of existing cross section data in nuclear criticality calculations have been a prime motivator for the new cross-section measurements. Our new capture cross sections of aluminium, silicon, chlorine, fluorine and potassium in the energy range from 100 eV to 600 keV are substantially different from the cross sections in evaluated nuclear data files of ENDF/B-VI and JENDL-3.2.

Chemoradiation therapy is effective for the palliative treatment of malignant dysphagia

Between 1993 and 2001, 106 patients with esophageal cancer were reviewed at a multidisciplinary clinic and treated with palliative intent by chemoradiation therapy. This study assesses the palliative benefit on dysphagia and documents the toxicity of this treatment. The study population comprised 72 men and 34 women with a median age of 69 years. Patients were treated with a median radiation dose of 35 Gy in 15 fractions with a concurrent single course of 5 FU-based chemotherapy. Dysphagia was measured at the beginning and completion of treatment and at monthly intervals until death, using a modified DeMeester (4-point) score. Treatment was well tolerated, with only 5% of patients failing to complete therapy. The treatment-related mortality was 6%. The median survival for the study population was 7 months. The median baseline score at presentation was 2 (difficulty with soft food). Following treatment, 49% of patients were assessed as having a dysphagia score of 0 (no dysphagia). Seventy-eight per cent had an improvement of at least one grade in their dysphagia score after treatment. Only 14% of patients showed no improvement with treatment. Fifty-one per cent maintained improved swallowing until the time of last follow-up or death. This single-institution study shows that chemoradiation therapy administered for the palliation of malignant dysphagia is well tolerated and produces a sustainable normalization in swallowing for almost half of all patients.

Use of oesophagogastroscopy to assess the response of oesophageal carcinoma to neoadjuvant therapy

BACKGROUND

Approximately 25 per cent of patients with oesophageal cancer who undergo neoadjuvant chemoradiotherapy have no evidence of tumour in the resected specimen (complete pathological response). Those who do not respond have a poor 5-year survival compared with complete responders, regardless of whether or not they undergo surgery. Selecting for surgery only those who have a response to neoadjuvant therapy has the potential to improve overall survival as well as to rationalize the management of non-responders. This study assessed the accuracy of oesophagogastroscopy in this setting.

METHODS

A prospective database of 804 patients undergoing oesophageal resection for carcinoma was reviewed. Endoscopic assessment of the response to neoadjuvant therapy in 100 consecutive patients was compared with the pathological assessment of response. The survival for each level of response was compared.

RESULTS

At endoscopy 30 patients were considered to have had a complete response. This was confirmed pathologically in 15 patients. Survival was improved in those with a pathologically confirmed complete response (3-year survival rate 62.4 (s.e. 12.9) per cent) compared with non-responders (16.3 (s.e. 6.6) per cent). Those with microscopic residual disease also had an improved 3-year survival rate (46.3 (s.e. 12.2) per cent); however, oesophagogastroscopy failed to identify this subset.

CONCLUSION

Oesophagogastroscopy may be useful in the assessment of tumour response to neoadjuvant therapy. However, owing to its poor accuracy patients should not be excluded from further therapeutic intervention on the basis of this assessment alone.

Cross-protection experiments with parasitoids in the genus Microplitis (Hymenoptera: Braconidae) suggest a high level of specificity in their associated bracoviruses

The immunological and developmental effects of bracoviruses (BVs) from three parasitoids in the genus Microplitis (Braconidae: Microgastrinae) were compared in the hosts Pseudoplusia includens and Heliothis virescens (Lepidoptera: Noctuidae). Southern blotting experiments indicated that viral DNAs from Microplitis demolitor bracovirus (MdBV) cross-hybridized with viral DNAs from Microplitis croceipes bracovirus (McBV) and Microplitis mediator bracovirus (MmBV) under conditions of high stringency. Injection of calyx fluid plus venom from each parasitoid species dose-dependently delayed development of P. includens and H. virescens. Each virus also inhibited pupation of P. includens but not H. virescens. In situ hybridization experiments indicated that MdBV and McBV persistently infect hemocytes in both hosts while MmBV persistently infects hemocytes in P. includens but not H. virescens. While MdBV infection induced a loss of adhesion by most plasmatocytes, McBV and MmBV infection induced a loss of adhesion in less than 50% of cells. Cross-protection experiments indicated that calyx fluid plus venom from one species usually protected progeny of another species from encapsulation but did not always promote successful development.

Selective and divergent regulation of cortical 5-HT(2A) receptors in rabbit

It is well established that repeated administration of both 5-hydroxytryptamine(2) (5-HT(2)) receptor agonists and antagonists decreases the density of 5-HT(2A) and 5-HT(2C) receptors. However, the regulation of these two receptors has not been studied in the same tissue. Therefore, we examined the effects of repeated daily injections of the 5-HT(2) receptor agonists (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) and D-lysergic acid diethylamide (LSD) and the antagonists d-2-bromolysergic acid diethylamide hydrogen tartrate (BOL) and alpha-phenyl-2-(2-phenylethyl)-4-piperidinemethanol (MDL 11,939) on rabbit cortical 5-HT(2A) and 5-HT(2C) receptors. Repeated administration of DOI, LSD, or BOL decreased cortical 5-HT(2A) receptor density but had no effect on the density of cortical 5-HT(2C) receptors. Repeated administration of the selective 5-HT(2A) receptor antagonist MDL 11,939 significantly increased 5-HT(2A) receptor density. This unexpected outcome also occurred without any change in cortical 5-HT(2C) receptor density. The down-regulation of 5-HT(2A) receptors produced by chronic administration of BOL was associated with a decrease in DOI-elicited head bobs, whereas 5-HT(2A) receptor up-regulation produced by MDL 11,939 was associated with an increase in DOI-elicited head bobs compared with controls. These studies demonstrate that 5-HT(2A) receptor antagonists can both down- and up-regulate the density of cortical 5-HT(2A) receptors and these changes in receptor density have functional consequences for 5-HT(2A) receptor-mediated behaviors. Furthermore, because DOI, LSD, and BOL have approximately equal affinities for the 5-HT(2A) and 5-HT(2C) receptors, these results suggest that different mechanisms regulate 5-HT(2A) and 5-HT(2C) receptor density, in that chronic occupation of 5-HT(2C) receptors does not modulate their density in rabbit frontal cortex.

Noncommutative field theory and Lorentz violation

The role of Lorentz symmetry in noncommutative field theory is considered. Any realistic noncommutative theory is found to be physically equivalent to a subset of a general Lorentz-violating standard-model extension involving ordinary fields. Some theoretical consequences are discussed. Existing experiments bound the scale of the noncommutativity parameter to (10 TeV)(-2).

Localization of small esophageal cancers for radiation planning using endoscopic contrast injection: report on a series of eight cases

Recently, Barrett's esophagus and early adenocarcinomas have been detected increasingly frequently in routine follow-up of patients with gastroesophageal reflux. Although surgery is the treatment of choice, some patients are medically unfit for esophagectomy and, in this case, the only alternative curative therapy is radical chemoradiation therapy. In addition, some patients who present with symptoms have small tumors that cannot be localized accurately using routine imaging techniques. This report describes a series of eight patients with small esophageal cancers in whom the tumors were successfully localized following endoscopic injection of contrast, and treated with chemoradiation therapy. The treatment was successful in seven patients. This method of tumor localization demonstrated that conventional techniques are mostly unreliable when applied to very early cancers.

The p38 mitogen-activated protein kinase is involved in associative learning in rabbits

This study examined the role of the mitogen-activated protein kinase (MAPK) family during acquisition of the rabbit's classically conditioned eye-blink response. Eye-blink conditioning produced a significant, bilateral activation of both extracellular signal-regulated protein kinases (ERKs) and p38 MAPK in the anterior cerebellar vermis. There was also a significant bilateral activation of ERKs in the dorsal hippocampus with no change in p38 MAPK. These changes were seen at 2 min after the last conditioning session, were maintained for at least 180 min, and occurred without any change in the protein expression of either ERKs or p38 MAPK. There were no changes in ERKs or p38 MAPK in frontal cortex, in cerebellar hemispheral lobule VI, or in a section of brainstem containing the inferior olive. Moreover, the stress-related protein kinase Jun N-terminal kinase (JNK), another subfamily of MAPKs, was not altered in any of the brain regions examined. Animals receiving explicitly unpaired presentations of a conditioned stimulus and an unconditioned stimulus did not acquire conditioned responses (CRs) and did not demonstrate any changes in ERKs, p38 MAPK, or JNK. The intraventricular injection of SB203580, a selective p38 MAPK inhibitor, significantly retarded CR acquisition and blocked the learning-related increases in p38 MAPK activity in the anterior vermis. PD98059, a selective MAPK kinase inhibitor, had a smaller and only marginally significant effect on CR acquisition, although it did block the learning-related increases in ERK activity in both the hippocampus and anterior vermis. These results indicate that p38 MAPK is activated during associative learning and may play a role in the transcriptional events that lead to memory consolidation.

Effects of prenatal exposure to cocaine on the developing brain: anatomical, chemical, physiological and behavioral consequences

Earlier studies of human infants and studies employing animal models had indicated that prenatal exposure to cocaine produced developmental changes in the behavior of the offspring. The present paper reports on the results obtained in a rabbit model of in utero exposure to cocaine using intravenous injections (4 mg/kg, twice daily) that mimic the pharmacokinetics of crack cocaine in humans. At this dose, cocaine had no effect on the body weight gain of dams, time to delivery, litter size and body weight or other physical characteristics of the offspring. In spite of an otherwise normal appearance, cocaine-exposed neonates displayed a permanent impairment in signal transduction via the D1 dopamine receptor in caudate nucleus, frontal cortex and cingulate cortex due to an uncoupling of the receptor from its associated Gs protein. This uncoupling in the caudate nucleus was shown to have behavioral consequences in that young or adult rabbits, exposed to cocaine in utero, failed to demonstrate amphetamine-elicited motor responses normally seen after activation of D1 receptors in the caudate. The cocaine progeny also demonstrated permanent morphological abnormalities in the anterior cingulate cortex due to uncoupling of the D1 receptor and the consequent inability of dopamine to regulate neurite outgrowth during neuronal development. Consistent with the known functions of the anterior cingulate cortex, adult cocaine progeny demonstrated deficits in attentional processes. This was reflected by impairment in discrimination learning during classical conditioning that was due to an inability to ignore salient stimuli even when these were not relevant to the task. The impairment in discrimination learning also occurred in an instrumental avoidance task and could be shown to be due to an impairment of cingulothalamic learning-related neuronal coding. It was proposed that the selective loss of D1-related neurotransmission in the anterior cingulate cortex prevented an appropriate activation of GABA neurons and thus a loss of inhibitory regulation that is necessary for processes involved in associative attention. Taken together, these findings suggest that the uncoupling of the D1 receptor from its G protein may be the fundamental source of the anatomic, cognitive and motor disturbances seen in rabbits exposed to cocaine in utero. Moreover, the long-term cognitive and motor deficits observed in the rabbit model are in agreement with the recent reports indicating that persistent attentional and other behavioral deficits may be evident in cocaine-exposed children as they grow older and are challenged to master more complex cognitive tasks.

Antagonist binding at 5-HT(2A) and 5-HT(2C) receptors in the rabbit: high correlation with the profile for the human receptors

This study examined the binding of serotonin receptor antagonists at the 5-HT(2A) and 5-HT(2C) receptors of the rabbit's cerebral cortex. The 5-HT(2A) receptor was characterized by the binding of [3H]MDL 100,907 (R(+)-alpha-(2, 3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methan ol) to cortical membranes and the 5-HT(2C) receptor by the binding of [3H]mesulergine in the presence of the selective 5-HT(2A) receptor ligand spiperone. Both [3H]MDL 100,907 and [3H]mesulergine demonstrated high affinity binding to single sites in rabbit membranes. Based on Scatchard plots of [3H]MDL 100,907 binding, the mean B(max) was 8.5+/-0.7 fmol/mg tissue and the mean K(d) was 33. 1+/-3.5 pM. For [3H]mesulergine binding the mean B(max) was 3.70+/-0. 58 fmol/mg tissue and the mean K(d) was 0.35+/-0.05 nM. Binding of [3H]MDL 100,907 to the 5-HT(2A) receptor and of [3H]mesulergine to the 5-HT(2C) receptor was confirmed by displacement studies with highly selective 5-HT(2A) and 5-HT(2C) receptor ligands. The pharmacological profile of these ligands in rabbits correlated highly with published values for 5-HT(2A) (r=0.91, P<0.001) and 5-HT(2C) (r=0.94, P<0.001) receptors in humans. There was also a high correlation between the profiles for human and rat 5-HT(2C) receptor (r=0.92, P<0.001), but not for 5-HT(2A) receptors (r=0.53, P>0.10). It was concluded that the rabbit provides an appropriate animal model for studies attempting to predict the pharmacology of human 5-HT(2A) and 5-HT(2C) receptors.

Technique and pitfalls of ultrasound-guided core-needle biopsy of the breast

When using ultrasound guidance to perform core-needle biopsy, the curvature of the breast can be used to advantage. By entering the breast from the periphery, chest wall injury is avoided and needle visualization is improved. Visualization of the needle is expedited by bringing the needle to the lesion by using a gentle sweeping motion while keeping the transducer relatively fixed in position. Standard techniques can be modified for difficult lesions, such as those that are mobile, deep, small, or in a large breast. Careful correlation with the mammogram will insure biopsy of the corresponding sonographic lesion. Although complications are uncommon, hematoma or infection may occur after the procedure. With practice, application of standard and modified techniques can result in efficient and accurate ultrasound-guided percutaneous core-needle biopsy of the breast.

MRI-guided needle localization: technique

Magnetic resonance imaging (MRI) is being used increasingly in breast cancer diagnosis. Such indications include the search for a breast primary in women with metastatic carcinoma in the axillary lymph nodes, improving surgical planning in women with a biopsy-proven breast cancer, and in screening very high-risk women. If a suspicious lesion is found by MRI, localization with either directed additional mammographic or sonographic views or with MRI-guided needle localization or biopsy is necessary. We describe the use of a biopsy device with embedded internal fiducial markers. The coordinates for needle placement are calculated by distances between the fiducial markers and the lesion. The technique is simple to master and is aided by the use of a practice phantom.

Dissociable effects of the 5-HT(2) antagonist mianserin on associative learning and performance in the rabbit

Serotonin 5-HT(2) antagonists that significantly retard the acquisition of classically conditioned responses (CRs) also impair the performance of the unconditioned response (UR). Effects on the UR appear to be due to an inverse agonist action at the 5-HT(2) receptor. These findings raised the possibility that the learning deficits were either secondary to a performance deficit and/or that the retardation of learning was not due to actions at the serotonin 5-HT(2) receptor. In this study, we examined the effects of the 5-HT(2)-receptor antagonists, namely mianserin and D-2-bromolysergic acid diethylamide hydrogen tartrate (BOL), on CR acquisition. We also determined whether the retarded acquisition of CRs produced by mianserin (a) was due to an action at the 5-HT(2) receptor and (b) was secondary to a performance deficit. Effects of drugs on CR acquisition, maintenance, and retention were determined during trace-conditioning of the rabbit's nictitating membrane (NM) response. BOL (0.058 to 5.8 micromol/kg) had no effect on CR acquisition, whereas mianserin (0.1 to 10 micromol/kg) produced a significant and dose-dependent retardation of CR acquisition. The retarded CR acquisition produced by mianserin (10 micromol/kg) was due to its actions at the 5-HT(2) receptor, because this effect was completely blocked by a dose of BOL (5.8 micromol/kg) that had no effect when given alone. Neither maintenance nor retention of learning was affected by mianserin treatment during acquisition. We conclude that mianserin acts as an inverse agonist at the serotonin 5-HT(2) receptor to produce both a retardation of CR acquisition and an impairment of the UR. However, the learning and performance effects of mianserin are separable.

Competition induces adaptive shifts in caste ratios of a polyembryonic wasp

An important transition in insect life-history evolution was the shift from a solitary existence to living in groups comprising specialized castes. Caste-forming species produce some individuals that reproduce and others with worker functions that have few or no offspring. Morphologically specialized castes are well known in eusocial species like ants and termites, but castes have also evolved in less-studied groups like thrips, aphids and polyembryonic wasps. Because selection acts at both the individual and the colony level, ratios of investment in different castes are predicted to vary with environmental factors like competition and resources. However, experimental evidence for adaptive shifts in caste ratios is limited owing to the experimental difficulty of manipulating factors thought to influence caste ratios, and because some species produce behaviourally flexible castes that switch tasks in response to colony needs. Unlike other caste-forming species, the broods of polyembryonic wasps develop clonally, so that increased production of one caste probably results in decreased production of the other. Here we show that the polyembryonic wasp Copidosoma floridanum alters caste ratios in response to interspecific competition. Our results reveal a distinct trade-off by C. floridanum between reproduction and defence, and show experimentally that caste ratios shift in an adaptive manner.

Association of infiltrating lobular carcinoma with positive surgical margins after breast-conservation therapy

OBJECTIVE

To determine whether infiltrating lobular carcinoma (ILC) is associated with high positive-margin rates for single-stage lumpectomy procedures, and to define clinical, mammographic, or histologic characteristics of ILC that might influence the positive-margin rate, thereby affecting treatment decisions.

SUMMARY BACKGROUND DATA

Infiltrating lobular cancer represents approximately 10% of all invasive breast carcinomas and is often poorly defined on gross examination.

METHODS

A group of 47 patients with biopsy-proven ILC undergoing breast-conservation therapy (BCT) at the University of Virginia Health Sciences Center between 1975 and 1999 was compared with a group of 150 patients with infiltrating ductal cancer undergoing BCT during the same time period. The pathology of the lumpectomy specimen was reviewed for each patient to confirm surgical margin status. Office and surgical notes as well as mammography reports were examined to determine whether the lesions were deemed palpable before and during surgery. Patients were stratified according to age, family history, tumor size, tumor location, and histologic features of the tumor.

RESULTS

The incidence of positive margins was greater in the ILC group compared with the infiltrating ductal cancer group. Patient age, family history, and preoperative palpability of the tumor did not correlate with surgical margin status. Of the mammographic features identified, including spiculated mass, calcifications, architectural distortion, and other densities, only architectural distortion predicted positive surgical margin status. Tumor grade, tumor size, lymph node status, and receptor status were not predictive of surgical margin status.

CONCLUSIONS

For patients with ILC, BCT is feasible, but these patients are at high risk of tumor-positive resection margins (51% incidence) after the initial resection. Only the mammographic finding of architectural distortion was identified as a preoperative marker reliably identifying a subgroup of ILC patients at especially high risk for a positive surgical margin. For all patients with ILC considering BCT, careful counseling about the potential need for a second procedure to treat the positive margin should be included in the treatment discussion.

Associative learning is enhanced by selective neuronal nitric oxide synthase inhibitors and retarded by a nitric oxide donor in the rabbit

RATIONALE

Previous studies had reported that the nitric oxide (NO) donor, sodium nitroprusside (SNP), retarded and the non-specific NO synthase (NOS) inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME), enhanced acquisition of classically conditioned responses (CRs). These effects of IV SNP and IP L-NAME on CR acquisition occurred in the absence of any effect on non-associative processes or performance variables and at a time when there were no alterations in blood pressure or heart rate.

OBJECTIVES

In this study, we examined whether the changes in associative learning produced by L-NAME and SNP were due to their central effects on NO content of brain. To this end, we examined the effects of the selective neuronal NOS inhibitors 7-nitroindazole (7-NI) and AR-R 17477 and the effects of central (ICV) administration of the NO donor SNP on learning.

METHODS

Effects of drugs on CR acquisition were determined during classical conditioning of the rabbit's nictitating membrane (NM) response. Explicitly unpaired presentations of conditioned stimuli (CSs) and unconditioned stimuli (USs) were employed to measure non-associative levels of responding and unconditioned response (UR) topography.

RESULTS

The SC injection of 7-NI and AR-R 17477 significantly enhanced associative learning while ICV administration of SNP significantly retarded learning.

CONCLUSION

Production of NO within the brain by neuronal NOS normally acts to retard associative learning presumably by decreasing excitability within neuronal circuits involved in the acquisition of the classically conditioned NM reflex.

Apparent ipsilateral decrease in breast size at mammography: a sign of infiltrating lobular carcinoma

PURPOSE

To assess if infiltrating lobular carcinoma (ILC) is associated with an ipsilateral mammographic decrease in breast size.

MATERIALS AND METHODS

Mammographic change in size was evaluated by measuring the distance from the nipple to the pectoralis major muscle on the mediolateral oblique view of the diagnostic mammogram and on a preceding mammogram in 30 patients with ILC. Clinical, mammographic, and histopathologic findings were retrospectively reviewed.

RESULTS

Five patients (17%) had an ipsilateral decrease in mammographic size. No patients noticed a physical decrease in breast size. Patients with an ipsilateral decrease in mammographic size most commonly had breast thickening at examination (four of five patients [80%], P < .001) and either a focal asymmetry density (three of five patients [60%]) or architectural distortion (one of five patients [20%]) at mammography; those patients with no change in size most commonly had a palpable mass (six of 25 patients [24%]) or normal findings (19 of 25 patients [76%]) and a mass (13 of 25 patients [52%]) at mammography. The mean tumor size was 66 mm for those with an ipsilateral size decrease and 16 mm for those with no size decrease (P < .001). At histologic analysis, tumors associated with an ipsilateral decrease in mammographic size had more diffuse involvement of the breast, and discrete masses were not seen.

CONCLUSION

An apparent decrease in mammographic size may help identify cases of ILC, especially when associated with thickening at clinical examination and focal asymmetric density at mammography.

Effects of prenatal cocaine exposure on amphetamine-induced dopamine release in the caudate nucleus of the adult rabbit

Acute amphetamine (AMPH) challenge has been used to probe the neurochemical and behavioral integrity of dopaminergic neurons under various conditions including prenatal cocaine exposure. In this study, we employed in vivo microdialysis to examine the effects of prenatal cocaine exposure on AMPH-induced dopamine (DA) release in the caudate nucleus of the awake adult rabbit. Pregnant rabbits were given intravenous injections of either saline or cocaine (4 mg/kg) twice a day from gestational day 8 (G8) through G29. Microdialysis was performed in adult saline and cocaine progeny at approximately postnatal day 70 (P70). There were no significant differences between cocaine and saline progeny in their basal concentrations of DA or its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). AMPH (5 mg/kg, i.v.) significantly increased extracellular DA in the caudate of both groups. However, AMPH-induced DA release was 2 to 3-fold greater in cocaine progeny than in the saline controls. Although, DOPAC decreased in both groups following AMPH injection, there was no significant group effect. In addition, there were no significant changes in concentrations of HVA. AMPH is known to release DA by a mechanism of exchange diffusion via the presynaptic DA transporter (DAT). Therefore, we examined the binding of [(3)H]WIN 35,428 to membrane fractions prepared from fresh caudate tissue to determine whether prenatal exposure to cocaine had altered the density (B(max)) or affinity (K(d)) of the DAT. While the B(max) for [(3)H]WIN 35,428 binding increased 3-fold between P3 and P120, there were no significant differences between saline and cocaine progeny at any age examined. The K(d) for [(3)H]WIN 35,428 binding did not change with postnatal age and did not differ between cocaine and saline progeny. These findings suggest that prenatal exposure to cocaine produces a long-term increase in the size of the presynaptic, AMPH releasable, cytoplasmic pool of DA.

Use and cost of breast imaging for postmenopausal women undergoing hormone replacement therapy

OBJECTIVE

The purpose of this study was to evaluate the use and associated costs of breast imaging studies for postmenopausal women undergoing hormone replacement therapy (HRT).

MATERIALS AND METHODS

Clinical findings, mammographic findings, and imaging studies performed on 1133 postmenopausal women during a 5-month period in 1996 were retrospectively reviewed. Cost was estimated using Medicare reimbursement rates.

RESULTS

Of the 1133 women, 699 (62%) underwent HRT. The number of women with breast complaints was similar for those undergoing (n = 62, 9%) and not undergoing (n = 26, 6%) HRT. Benign findings were more common for women undergoing HRT (n = 186, 27%) than for women not undergoing HRT (n = 92, 21%) (p = .04). Masses were noted in 133 of the women undergoing HRT (19%), compared with 42 women not undergoing HRT (10%) (p < .000). Specifically, cysts were seen in 46 women undergoing HRT (7%), compared with five women not undergoing HRT (1%) (p < .0001). Diagnostic mammograms and sonograms were more commonly obtained in women undergoing HRT (33 and 13 per 100 women, respectively) than in women not undergoing HRT (24 and seven per 100, respectively) (p = .014 and .0007, respectively). The overall cost of breast imaging was $89 for each woman undergoing HRT and $87 for each woman not undergoing HRT.

CONCLUSION

Benign mammographic findings, primarily cysts, in women undergoing HRT result in an increased use of diagnostic mammography and sonography. The minimal increase in cost should not be a significant factor in the decision to use HRT.

Effect of 5-HT2 receptor antagonists on a cranial nerve reflex in the rabbit: evidence for inverse agonism

This study examined the role of the serotonin 5-HT2 receptor in motor function by examining the effect of antagonists on the motor performance of a cranial nerve reflex, the nictitating membrane (NM) reflex of the rabbit. The NM reflex was elicited by varying intensities of a tactile stimulus and the magnitudes of the elicited responses were measured at each intensity. Dose-response curves were obtained for the effects of several 5-HT2 receptor antagonists on response magnitude. d-Bro-molysergic acid diethylamide (BOL), LY-53,857 and ketanserin had no significant effect on the magnitude of the NM reflex, indicating that they are neutral antagonists. However, the 5-HT2 receptor antagonists ritanserin, MDL-11,939 and mianserin produced a significant reduction in response magnitude with no significant effects on response frequency, suggesting that they were acting as inverse agonists at the 5-HT2 receptor. The reduction in reflex magnitude produced by mianserin (10 micromol/kg) was fully blocked by BOL (5.8 micromol/kg), supporting the conclusion that mianserin was producing a reduction in reflex magnitude through an effect at the 5-HT2 receptor. The occurrence of inverse agonism suggests the possible existence of constitutive activity in vivo. We conclude that the 5-HT2 receptor (either 2A or 2C) plays an important role in motor function, perhaps by providing a tonic influence on motor systems.