Fewer butterflies seen by community scientists across the warming and drying landscapes of the American West

Uncertainty remains regarding the role of anthropogenic climate change in declining insect populations, partly because our understanding of biotic response to climate is often complicated by habitat loss and degradation among other compounding stressors. We addressed this challenge by integrating expert and community scientist datasets that include decades of monitoring across more than 70 locations spanning the western United States. We found a 1.6% annual reduction in the number of individual butterflies observed over the past four decades, associated in particular with warming during fall months. The pervasive declines that we report advance our understanding of climate change impacts and suggest that a new approach is needed for butterfly conservation in the region, focused on suites of species with shared habitat or host associations.

Climate Change and Local Host Availability Drive the Northern Range Boundary in the Rapid Expansion of a Specialist Insect Herbivore, Papilio cresphontes

Species distributions, abundance, and interactions have always been influenced by human activity and are currently experiencing rapid change. Biodiversity benchmark surveys traditionally require intense human labor inputs to find, identify, and record organisms limiting the rate and impact of scientific enquiry and discovery. Recent emergence and advancement of monitoring technologies have improved biodiversity data collection to a scale and scope previously unimaginable. Community science web platforms, smartphone applications, and technology assisted identification have expedited the speed and enhanced the volume of observational data all while providing open access to these data worldwide. How to integrate and leverage the data into valuable information on how species are changing in space and time requires new best practices in computational and analytical approaches. Here we integrate data from three community science repositories to explore how a specialist herbivore distribution changes in relation to host plant distributions and other environmental factors. We generate a series of temporally explicit species distribution models to generate range predictions for a specialist insect herbivore (Papilio cresphontes) and three predominant host-plant species. We find that this insect species has experienced rapid northern range expansion, likely due to a combination of the range of its larval host plants and climate changes in winter. This case study shows rapid data collection through large scale community science endeavors can be leveraged through thoughtful data integration and transparent analytic pipelines to inform how environmental change impacts where species are and their interactions for a more cost effective method of biodiversity benchmarking.

Linking monitoring and data analysis to predictions and decisions for the range-wide eastern black rail status assessment

The US Fish and Wildlife Service (USFWS) has initiated a re-envisioned approach for providing decision makers with the best available science and synthesis of that information, called the Species Status Assessment (SSA), for endangered species decision making. The SSA report is a descriptive document that provides decision makers with an assessment of the current and predicted future status of a species. These analyses support all manner of decisions under the US Endangered Species Act, such as listing, reclassification, and recovery planning. Novel scientific analysis and predictive modeling in SSAs could be an important part of rooting conservation decisions in current data and cutting edge analytical and modeling techniques. Here, we describe a novel analysis of available data to assess the current condition of eastern black rail Laterallus jamaicensis jamaicensis across its range in a dynamic occupancy analysis. We used the results of the analysis to develop a site occupancy projection model where the model parameters (initial occupancy, site persistence, colonization) were linked to environmental covariates, such as land management and land cover change (sea-level rise, development, etc.). We used the projection model to predict future status under multiple sea-level rise and habitat management scenarios. Occupancy probability and site colonization were low in all analysis units, and site persistence was also low, suggesting low resiliency and redundancy currently. Extinction probability was high for all analysis units in all simulated scenarios except one with significant effort to preserve existing habitat, suggesting low future resiliency and redundancy. With the results of these data analyses and predictive models, the USFWS concluded that protections of the Endangered Species Act were warranted for this subspecies.

Within-host competition drives energy allocation trade-offs in an insect parasitoid

Organismal body size is an important biological trait that has broad impacts across scales of biological organization, from cells to ecosystems. Size is also deeply embedded in life history theory, as the size of an individual is one factor that governs the amount of available resources an individual is able to allocate to different structures and systems. A large body of work examining resource allocation across body sizes (allometry) has demonstrated patterns of allocation to different organismal systems and morphologies, and extrapolated rules governing biological structure and organization. However, the full scope of evolutionary and ecological ramifications of these patterns have yet to be realized. Here, we show that density-dependent larval competition in a natural population of insect parasitoids (Drino rhoeo: Tachinidae) results in a wide range of body sizes (largest flies are more than six times larger (by mass) than the smallest flies). We describe strong patterns of trade-offs between different body structures linked to dispersal and reproduction that point to life history strategies that differ between both males and females and individuals of different sizes. By better understanding the mechanisms that generate natural variation in body size and subsequent effects on the evolution of life history strategies, we gain better insight into the evolutionary and ecological impacts of insect parasitoids in tri-trophic systems.

Limited phenological and dietary overlap between bee communities in spring flowering crops and herbaceous enhancements

Wild bee populations have undergone declines in recent years across much of the Western world, and these declines have the potential to limit yield in pollination-dependent crops. Highbush blueberry, Vaccinium corymbosum, and tart cherry, Prunus cerasus, are spring-blooming crops that rely on the movement of pollen by bees and other insects for pollination. Wild bee populations can be increased on farmland by providing floral resources, but whether the addition of these plants translates into increased pollinator density on crop flowers has not been documented in most cropping systems. To determine the importance of providing additional floral resources for wild bee pollinator communities, we selected blueberry fields and tart cherry orchards with and without herbaceous floral enhancements in western Michigan, USA. The bee communities visiting crop flowers, enhancements and control grassy field margins were sampled over a 5-yr period. In addition, the pollen diets of the most abundant wild bee crop pollinators were quantified across Michigan to better understand their foraging niches and to identify potentially important alternative host plants. The presence of floral enhancements did not increase the abundance of wild bees on either blueberry or cherry flowers during bloom. The bee community visiting blueberry was evenly composed of short-season bees that fly only during the spring and long-season bees that fly in both spring and summer. In contrast, the bee community visiting cherry was dominated by short-season spring bees. The majority of pollen collected by the wild bee communities visiting blueberry and cherry was from spring-flowering woody plants, with limited use of the herbaceous enhancements. Enhancements attracted greater abundance and species richness of bees compared to control areas, including twice as many floral specialists. Conserving summer-flying, grassland-associated bees is an appropriate goal for pollinator conservation programs. However, herbaceous enhancements may not provide adequate resources for the wild bees that pollinate spring-flowering crops. This study demonstrates that an examination of the pollen collected by wild bees across their flight periods can identify plant species to help them persist in intensively managed landscapes.

Innate and Learned Olfactory Responses in a Wild Population of the Egg Parasitoid Trichogramma (Hymenoptera: Trichogrammatidae)

Parasitoid insects face the fundamental problem of finding a suitable host in environments filled with competing stimuli. Many are deft sensors of olfactory cues emitted by other insects and the plants they live on, and use these cues to find hosts. Using olfactory cues from host-plants is effective because plants release volatile organic compounds (VOCs), in response to herbivory or oviposition, that contain information about the presence of hosts. However, plant-produced cues can also be misleading because they are influenced by a variety of stimuli (abiotic variation, infection and multiple sources of induction via herbivory or oviposition). Flexible behavior is one strategy that parasitoids may use to cope with variation in olfactory cues. We examine the innate and learned responses of a natural population of wasp egg parasitoids (Trichogramma deion and Trichogramma sathon) using a series of laboratory and field Y-olfactometer experiments. Wasps typically attack eggs of the hawkmoth Manduca sexta and Manduca quinquemaculata on native Datura wrightii plants in the southwestern United States. We show that Trichogramma wasps responded innately to VOCs produced by D. wrightii and could distinguish plants recently attacked by M. sexta from non-attacked plants. Furthermore, adult Trichogramma wasps were able to learn components of the VOC blend given off by D. wrightii, though they did not learn during exposure as pupae. By further exploring the behavioral ecology of a natural population of Trichogramma, we gain greater insight into how egg parasitoids function in tri-trophic systems.

Heat dissipation during hovering and forward flight in hummingbirds

Flying animals generate large amounts of heat, which must be dissipated to avoid overheating. In birds, heat dissipation is complicated by feathers, which cover most body surfaces and retard heat loss. To understand how birds manage heat budgets during flight, it is critical to know how heat moves from the skin to the external environment. Hummingbirds are instructive because they fly at speeds from 0 to more than 12 m s(-1), during which they transit from radiative to convective heat loss. We used infrared thermography and particle image velocimetry to test the effects of flight speed on heat loss from specific body regions in flying calliope hummingbirds (Selasphorus calliope). We measured heat flux in a carcass with and without plumage to test the effectiveness of the insulation layer. In flying hummingbirds, the highest thermal gradients occurred in key heat dissipation areas (HDAs) around the eyes, axial region and feet. Eye and axial surface temperatures were 8°C or more above air temperature, and remained relatively constant across speeds suggesting physiological regulation of skin surface temperature. During hovering, birds dangled their feet, which enhanced radiative heat loss. In addition, during hovering, near-body induced airflows from the wings were low except around the feet (approx. 2.5 m s(-1)), which probably enhanced convective heat loss. Axial HDA and maximum surface temperature exhibited a shallow U-shaped pattern across speeds, revealing a localized relationship with power production in flight in the HDA closest to the primary flight muscles. We conclude that hummingbirds actively alter routes of heat dissipation as a function of flight speed.

Protection via parasitism: Datura odors attract parasitoid flies, which inhibit Manduca larvae from feeding and growing but may not help plants

Insect carnivores frequently use olfactory cues from plants to find prey or hosts. For plants, the benefits of attracting parasitoids have been controversial, partly because parasitoids often do not kill their host insect immediately. Furthermore, most research has focused on the effects of solitary parasitoids on growth and feeding of hosts, even though many parasitoids are gregarious (multiple siblings inhabit the same host). Here, we examine how a gregarious parasitoid, the tachinid fly Drino rhoeo, uses olfactory cues from the host plant Datura wrightii to find the sphingid herbivore Manduca sexta, and how parasitism affects growth and feeding of host larvae. In behavioral trials using a Y-olfactometer, female flies were attracted to olfactory cues emitted by attacked plants and by cues emitted from the frass produced by larval Manduca sexta. M. sexta caterpillars that were parasitized by D. rhoeo grew to lower maximum weights, grew more slowly, and ate less of their host plant. We also present an analytical model to predict how tri-trophic interactions change with varying herbivory levels, parasitization rates and plant sizes. This model predicted that smaller plants gain a relatively greater benefit compared to large plants in attracting D. rhoeo. By assessing the behavior, the effects of host performance, and the variation in ecological parameters of the system, we can better understand the complex interactions between herbivorous insects, the plants they live on and the third trophic level members that attack them.

Glucoregulatory effects and prolonged duration of action of davalintide: a novel amylinomimetic peptide

AIMS

Davalintide is a second-generation amylinomimetic peptide possessing enhanced pharmacological properties over rat amylin to reduce food intake in preclinical models. The current experiments in rats describe additional glucoregulatory actions of davalintide consistent with amylin agonism, and explore the duration of action of these effects.

METHODS

Subcutaneous (SC) injection of davalintide slowed gastric emptying with equal potency to amylin (ED₅₀'s = 2.3 and 4.1 µg/kg). This effect was maintained for 8 h with davalintide, but not amylin. Intraperitoneal injection of davalintide also reduced food intake with a potency similar to amylin (ED₅₀'s = 5.0 and 11.3 µg/kg). Consistent with amylin agonism, davalintide (10 µg/kg, SC) suppressed the plasma glucagon response over 90 min following an intravenous arginine bolus in anaesthetized rats. The elimination t(½) of davalintide (200 µg/kg, SC) was 26 min, similar to the t(½) of amylin, suggesting that pharmacokinetic-independent mechanisms contribute to davalintide's enhanced duration of action. Binding kinetic studies using ¹²⁵I davalintide revealed no appreciable dissociation from the amylin nucleus accumbens receptor after 7 h while ¹²⁵I rat amylin did dissociate from this receptor (K(off) = 0.013/min). Sustained SC infusion of davalintide (275 µg/kg/day) or amylin (300) decreased plasma glucose after an oral glucose challenge at 2 weeks (by 27 and 31%) and suppressed gastric emptying at 3 weeks (by 29 and 47%), demonstrating durable glucoregulatory actions of both peptides.

CONCLUSIONS

These data show glucoregulatory properties of davalintide consistent with amylin agonism and suggest that slowed receptor dissociation plays a role in davalintide's prolonged pharmacodynamic actions.

Davalintide (AC2307), a novel amylin-mimetic peptide: enhanced pharmacological properties over native amylin to reduce food intake and body weight

OBJECTIVE

The current set of studies describe the in vivo metabolic actions of the novel amylin-mimetic peptide davalintide (AC2307) in rodents and compares these effects with those of the native peptide.

RESEARCH DESIGN AND METHODS

The anti-obesity effects of davalintide were examined after intraperitoneal injection or sustained peripheral infusion through subcutaneously implanted osmotic pumps. The effect of davalintide on food intake after lesioning of the area postrema (AP) and neuronal activation as measured by c-Fos, were also investigated.

RESULTS

Similar to amylin, davalintide bound with high affinity to amylin, calcitonin and calcitonin gene-related peptide receptors. Acutely, davalintide displayed greater suppression of dark-cycle feeding and an extended duration of action compared with amylin (23 versus 6 h). Davalintide had no effect on locomotor activity or kaolin consumption at doses that decreased food intake. Davalintide-induced weight loss through infusion was dose dependent, durable up to 8 weeks, fat-specific and lean-sparing, and was associated with a shift in food preference away from high-fat (palatable) chow. Metabolic rate was maintained during active weight loss. Both davalintide and amylin failed to suppress food intake after lesioning of the AP and activated similar brain nuclei, with davalintide displaying an extended duration of c-Fos expression compared with amylin (8 versus 2 h).

CONCLUSION

Davalintide displayed enhanced in vivo metabolic activity over amylin while retaining the beneficial properties possessed by the native molecule. In vitro receptor binding, c-Fos expression and AP lesion studies suggest that the metabolic actions of davalintide and amylin occur through activation of similar neuronal pathways.

Antiobesity action of peripheral exenatide (exendin-4) in rodents: effects on food intake, body weight, metabolic status and side-effect measures

BACKGROUND

Exenatide (exendin-4) is an incretin mimetic currently marketed as an antidiabetic agent for patients with type 2 diabetes. In preclinical models, a reduction in body weight has also been shown in low-fat-fed, leptin receptor-deficient rodents.

OBJECTIVE

To more closely model the polygenic and environmental state of human obesity, we characterized the effect of exenatide on food intake and body weight in high-fat-fed, normal (those with an intact leptin signaling system) rodents. As glucagon-like peptide-1 receptor agonism has been found to elicit behaviors associated with visceral illness in rodents, we also examined the effect of peripheral exenatide on kaolin consumption and locomotor activity.

METHODS AND RESULTS

High-fat-fed C57BL/6 mice and Sprague-Dawley rats were treated with exenatide (3, 10 and 30 microg/kg/day) for 4 weeks via subcutaneously implanted osmotic pumps. Food intake and body weight were assessed weekly. At 4 weeks, body composition and plasma metabolic profiles were measured. Kaolin consumption and locomotor activity were measured in fasted Sprague-Dawley rats following a single intraperitoneal injection of exenatide (0.1-10 microg/kg). Exenatide treatment in mice and rats dose-dependently decreased food intake and body weight; significant reductions in body weight gain were observed throughout treatment at 10 and 30 microg/kg/day (P<0.05). Decreased body weight gain was associated with a significant decrease in fat mass (P<0.05) with sparing of lean tissue. Plasma cholesterol, triglycerides and insulin were also significantly reduced (P<0.05). Exenatide at 10 microg/kg significantly reduced food intake (P<0.05) but failed to induce kaolin intake. In general, locomotor activity was reduced at doses of exenatide that decreased food intake, although a slightly higher dose was required to produce significant changes in activity.

CONCLUSION

Systemic exenatide reduces body weight gain in normal, high-fat-fed rodents, a model that parallels human genetic variation and food consumption patterns, and may play a role in metabolic pathways mediating food intake.

A review of treatment for carpal tunnel syndrome

PURPOSE

A common disorder encountered by healthcare specialists is carpal tunnel syndrome (CTS). CTS is a neuropathy disorder caused by compression on the median nerve.

METHOD

Currently, there are several treatment methods for CTS such as: (1) non-steroidal anti-inflammatory drugs (NSAIDs); (2) injection of medications; (3) immobilization by splinting; (4) rehabilitation modalities (therapeutic ultrasound, ASTM AdvantEDGE, stretching and strengthening); and (5) surgery by carpal tunnel release.

RESULTS

While NSAIDs, injections, and splinting have shown promise in relieving symptoms, long-term outcomes have been poor.

CONCLUSION

This article provides a background in current treatment methods and an insight into the focal point of the future.

Anterior knee pain: a clinical comparison of rehabilitation methods

OBJECTIVE

To compare different types of rehabilitation for anterior knee pain.

DESIGN

Prospective, randomized, blinded, and controlled study of 64 participants with anterior knee pain.

SETTING

Outpatient rehabilitation clinic and testing laboratory.

PARTICIPANTS

Participants were assigned in randomized fashion to three rehabilitation groups: traditional home rehabilitation (n = 20); physical therapy (n = 21); and home rehabilitation with a modified vastus medialis obliquis (VMO) specific straight leg raise (Muncie method; n = 23).

INTERVENTIONS AND MAIN OUTCOME MEASURES

Clinical data was obtained at 0, 2, 6, and 12 weeks. Cybex testing was performed at 0, 6, and 12 weeks.

RESULTS

Clinical outcome for the Muncie method indicated a statistically significant improvement in subjective pain and functional impairment ratings. Cybex testing in patients using the Muncie method demonstrated a statistically significant improvement in pain-free isometric contractions and maximum voluntary contraction. There were no significant differences between traditional home therapy and physical therapy.

CONCLUSION

Findings suggest that the Muncie method results in improved clinical outcome at a lower cost than traditional home and physical therapy and possibly improved VMO/quadriceps muscle balance. Patients with anterior knee pain may benefit from applying the Muncie method in a home therapy program.

Treating lateral epicondylitis

Lateral epicondylitis is a common problem among physically active individuals. One of the most important roles of the clinician is to provide the most effective rehabilitation intervention for the injured athlete and the physically active individual. Over 40 different treatment methods for lateral epicondylitis have been reported in the literature. Initially, lateral epicondylitis can be treated with rest, ice, tennis brace and/or injections. Injections are one of the most popular methods utilised, with a high success rate. However, when the condition is chronic or not responding to initial treatment, physical therapy is initiated. Common rehabilitation modalities utilised are ultrasound, phonophoresis, electrical stimulation, manipulation, soft tissue mobilisation, neural tension, friction massage, augmented soft tissue mobilisation (ASTM) and stretching and strengthening exercise. ASTM is becoming a more popular modality due to the detection of changes in the soft tissue texture as the patient progresses through the rehabilitation process. Other new modalities include laser and acupuncture. As a last resort for chronic or resistant cases, lateral epicondylitis may undergo surgery. Scientific research has found that all these methods have been inconsistently effective in treating lateral epicondylitis. Therefore, further research efforts are needed to determine which method is more effective.

Who is fighting for the right to die? Older women's participation in the Hemlock Society

Who is fighting for the right to die? Past literature has been mixed as to the membership of this social movement. In the current study, 6,398 Hemlock Society members were surveyed in an effort to answer questions concerning who is participating in the right to die movement, whether these participants are rapidly approaching their own death or reacting to the death of a loved one, and whether the movement is invigorated by singular activists. The findings indicate that older, white, wealthy, highly educated, economically and politically active women are in the forefront of the right to die movement. These women report currently being mentally and physically healthy, yet already having taken the steps that will allow them to have an element of control over their death. Finally, right to die support seems to be part of a larger collective network concerning health care and political policy issues.

Misty (m) affects growth traits

The misty (m) coat color mutation is commonly maintained in linkage disequilibrium with the obesity mutation diabetes (Leprdb) to serve as a marker for Leprdb genotype. Comparisons among Leprdb genotypes are made under the untested assumption that m has no effects on traits under investigation. We tested this assumption in a population segregating m in the absence of db. Analysis of growth curves revealed that m/m mice are smaller than M/M mice by the 2nd wk of life and remain smaller through the 5th wk of life. Analysis of variance of three traits measured at 35 days of age revealed that m/m mice are 8% shorter than M/M mice, weigh 15% less, and have 21% less inguinal adipose mass. These results indicate that m affects growth traits. Therefore, when m and Leprdb segregate in the same cross, interpretation of their effects is confounded by linkage. More accurate estimates of Leprdb genotype effects can be made by removing m from populations segregating Leprdb and using a direct assay to measure Leprdb genotype.

Chronic ankle pain and fibrosis successfully treated with a new noninvasive augmented soft tissue mobilization technique (ASTM): a case report

This clinical case report demonstrates the clinical effectiveness of a new form of soft tissue mobilization in the treatment of excessive connective tissue fibrosis (scar tissue) around an athlete's injured ankle. The scar tissue was causing the athlete to have pain with activity, pain on palpation of the ankle, decreased range of motion, and loss of function. Surgery and several months of conventional physical therapy failed to alleviate the athlete's symptoms. As a final resort, augmented soft tissue mobilization (ASTM) was administered. ASTM is an alternative nonsurgical treatment modality that is being researched at Performance Dynamics (Muncip, IN). ASTM is a process that uses ergonomically designed instruments that assist therapists in the rapid localization and effective treatment of areas exhibiting excessive soft tissue fibrosis. This is followed by a stretching and strengthening program. Upon the completion of 6 wk of ASTM therapy, the athlete had no pain and had regained full range of motion and function. This case report is an example of how a noninvasive augmented form of soft tissue mobilization (ASTM) demonstrated impressive clinical results in treating a condition caused by connective tissue fibrosis.

Substrate oxidation and energy expenditure in athletes and nonathletes consuming isoenergetic high- and low-fat diets

Changes in substrate oxidation with isoenergetic high-carbohydrate (HC) and high-fat (HF) diets in male nonathletic subjects, aerobically trained athletes, and weight-trained athletes were examined in a crossover study. A whole-room respiration chamber was used to measure 24-h energy expenditure (EE) and substrate oxidation with control, HC, or HF diets for 7 d. The nonathletic group had higher 24-h EE (P < 0.05), exercise EE (P < 0.03), and resting metabolic rate (P < 0.04) than did the aerobically trained athletes when these measurements were corrected for lean body mass. Fat oxidation was significantly correlated with lean body mass and diet. However, athletic status had no effect on substrate oxidation. Carbohydrate oxidation across groups increased acutely by 23% after 24 h of the HC diet (P < 0.0001). Carbohydrate balance increased significantly over time with the HC diet (P < 0.002) and decreased acutely after return to the control diet (P < 0.0001). With the HF diet, carbohydrate balance increased and was significantly different from balance with the control diet by day 7 (P < 0.03). Fat balance decreased significantly with both the HF (P < 0.04) and HC (P = 0.0075) diets by day 7. Carbohydrate oxidation correlated with carbohydrate intake with both the control (r = 0.61, P < 0.01) and HC diets (r = 0.59, P < 0.02), but not the HF diet. Fat oxidation was not correlated with fat intake. In conclusion, substrate oxidation in a respiration chamber is significantly affected by diet, but not by prior athletic training.

Absence of secretory phospholipase A2 gene alterations in human colorectal cancer

A potent modifying locus of intestinal tumorigenesis in the mouse was recently identified as secretory phospholipase A2 (sPLA2). The human homologue of sPLA2 maps to chromosome 1p35, a region frequently lost in human tumors. To evaluate the possibility that sPLA2 was a tumor suppressor gene that was the target of the 1p loss events, we identified polymorphisms within the human sPLA2 gene. Using these polymorphisms, 31% of 16 colorectal carcinomas were found to lose a sPLA2 allele. However, sequence analysis of the complete coding region of sPLA2 revealed no somatic mutations in the remaining allele of those tumors with allelic loss, nor in 18 additional colorectal cancers. Thus, sPLA2 is within the chromosomal region often lost during colorectal tumorigenesis, but mutations of this gene do not appear to play a major role in colorectal cancer development, and sPLA2 is unlikely to be the 1p35 tumor suppressor.

Replacement of the valvular prosthesis in a patient with a Bentall procedure

Patients who have had the Bentall-DeBono procedure using a composite conduit with a tissue valvular prosthesis pose a great challenge when problems develop with the tissue prosthesis. We herein report the surgical management of one such case, in which the valvular prosthesis was removed and replaced without replacement of the conduit.

Molecular Origin of Io's Fast Sodium

Neutral sodium emissions encircling Jupiter exhibit an intricate and variable structure that is well matched by a simple loss process from Io's atmosphere. These observations imply that fast neutral sodium is created locally in the Io plasma torus, both near Io and as much as 8 hours downstream. Sodium-bearing molecules may be present in Io's upper atmosphere, where they are ionized by the plasma torus and swept downstream. The molecular ions dissociate and dissociatively recombine on a short time scale, releasing neutral fragments into escape trajectories from Jupiter. This theory explains a diverse set of sodium observations, and it implies that molecular reactions (particularly electron impact ionization and dissociation) are important at the top of Io's atmosphere.

A feasibility study of the MTT assay for chemosensitivity testing in ovarian malignancy

We assess the feasibility of using the MTT assay as a measure of cell viability in chemosensitivity testing in ovarian malignancy. The assay utilises the conversion of the tetrazolium salt MTT to formazan by dehydrogenase enzymes in living cells. We show that the optical density of the formazan produced from MTT is directly proportional to the number of live cells tested. Optimum MTT conversion occurred after 4 h incubation and dimethyl sulphoxide was found to be the most suitable solvent for the formazan. Seventy-five samples of ascitic fluid and/or solid tumour were collected from 56 patients with FIGO stage III-IV ovarian adenocarcinoma. Malignant cell suspensions with a viability greater than 75% were prepared from 95% of ascitic fluid and 75% of biopsy samples by simple techniques. The effect of cytotoxic drugs was assessed in 91% of patients included in the study. Variation in drug effect between patients was evident following a 48 h incubation period and was reproducible. Overall platinum and anthraquinone analogues produced the greater effect but resistance did occur. Our results mirrored reported clinical response rates. Only one sample tested against chlorambucil showed any drug effect. As this assay produces results in a high percentage of tests and is rapid and simple it appears suitable for prospective clinical trials to correlate the in vitro results with in vivo response.

Skin-conductance orienting response in chronic schizophrenics: the role of neuroleptics

The primary aim of this study was to determine whether there is an association between neuroleptic treatment and skin-conductance orienting response (SCOR) nonresponding in chronic schizophrenics. In a design adapted to this purpose, we were unable to demonstrate a relationship between neuroleptics and nonresponding. Although inability to prove the null hypothesis precludes a claim that neuroleptic treatment and SCOR nonresponding are unrelated, internal evidence and prior studies strongly suggest that such a dissociation exists in most chronic schizophrenic nonresponders. We also found stable nonspecific and toxic skin conductance activity differences between SCOR "responders" and "nonresponders" on three occasions of testing. We interpret our results as bearing on state and trait issues in chronic schizophrenics.

Skin-conductance orienting response in chronic schizophrenics: The role of neuroleptics

The primary aim of this study was to determine whether there is an association between neuroleptic treatment and skin-conductance orienting response (SCOR) nonresponding in chronic schizophrenics. In a design adapted to this purpose, we were unable to demonstrate a relationship between neuroleptics and nonresponding. Although inability to prove the null hypothesis precludes a claim that neuroleptic treatment and SCOR nonresponding are unrelated, internal evidence and prior studies strongly suggest that such a dissociation exists in most chronic schizophrenic nonresponders. We also found stable nonspecific and toxic skin conductance activity differences between SCOR "responders" and "nonresponders" on three occasions of testing. We interpret our results as bearing on state and trait issues in chronic schizophrenics.

Open-heart surgery in Jehovah's Witnesses: experience in a Canadian hospital

Jehovah's Witnesses have religious belief precluding the use of blood. Few centers have attempted open-heart surgery bound by such strictures; as a result, availability of therapy for such patients has been limited. Many groups that have extensive experience with hemodilution for cardiopulmonary bypass have noted that these procedures can often be done with little or no use of blood. Our experience with 21 adult patients is presented in this paper.

Idiopathic prolapsed mitral leaflet syndrome. Angiographic-clinical correlations

Angiographic clinical correlations were made in 59 patients with prolapsed mitral leaflet syndrome. Eight had nonejection systolic clicks (group I), 20 had early, mid or late systolic murmurs with or without a systolic click (group II), and 31 had pansystolic murmurs (group III). Isolated prolapse of posterior leaflet (PL) scallops occurred in 42 and 17 had combined leaflet prolapse. The study demonstrated the following: (I) Group II patients usually had isolated PL prolapse with a predominant biscallop involvement while a high incidence of triple scallop prolapse and combined mitral leaflet prolapse occurred in group III. (II) Severe mitral regurgitation and a greater incidence of atrial fibrillation were seen in patients with triscallop prolapse and combined mitral leaflet prolapse. Mitral regurgitation was milder in patients with single and biscallop prolapse and, when severe, was associated with ruptured chordae. (III) ST-T wave abnormalities in the inferior leads were most frequent in patients with isolated PL prolapse. (IV) Systolic and diastolic asynergy occurred in 41 patients, most frequently in group II but also relatively frequently in group III (19 of 31). Segmental anterior dysfunction with normal ejection fraction was found in 18 patients, of whom 13 had early anterior wall relaxation. (V) Patients without asynergy were slightly older than those with it. More in the former group had severe mitral regurgitation and were clinically disabled from it.

Angiographic-morphologic correlation in patients with severe mitral regurgitation due to prolapse of the posterior mitral valve leaflet

Angiographic-morphologic correlation was done on findings in 16 patients with proven prolapse of the posterior mitral leaflet and severe mitral regurgitation. A triscalloped bulge into the left atrium in the left ventriculogram taken in the right anterior oblique projection is caused by prolapse of all three scallops of the posterior mitral leaflet. The prolapsed middle scallop produces a central bulge, the prolapsed posteromedial commissural scallop a posteroinferior bulge ih tne area of the posteromedial commissure, and the prolapsed anterolateral commissural scallop an anterosuperior bulge in the anterolateral commissural area. The latter is often overlapped by the aortic root but if prominent, juts beyond it. Correlation proved that the diagnosis of individual scallop prolapse in this syndrome can be made accurately despite gross mitral regurgitation.

Massive pulmonary embolism: successful surgical treatment using cardiopulmonary bypass

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