Kv4 channel expression and kinetics in GABAergic and non-GABAergic rNST neurons.

The rostral nucleus of the solitary tract (rNST) serves as the first central relay in the gustatory system. In addition to synaptic interactions, central processing is also influenced by the ion channel composition of individual neurons. For example, voltage-gated K+ channels such as outward K+ current (IA) can modify the integrative properties of neurons. IA currents are prevalent in rNST projection cells but are also found to a lesser extent in GABAergic interneurons. However, characterization of the kinetic properties of IA, the molecular basis of these currents, as well as the consequences of IA on spiking properties of identified rNST cells is lacking. Here, we show that IA in rNST GABAergic (G+) and non-GABAergic (G-) neurons share a common molecular basis. In both cell types, there was a reduction in IA following treatment with the specific Kv4 channel blocker AmmTx3. However, the kinetics of activation and inactivation of IA in the two cell types were different with G- neurons having significantly more negative half-maximal activation and inactivation values. Likewise, under current clamp, G- cells had significantly longer delays to spike initiation in response to a depolarizing stimulus preceded by a hyperpolarizing prepulse. Computational modeling and dynamic clamp suggest that differences in the activation half-maximum may account for the differences in delay. We further observed evidence for a window current under both voltage clamp and current clamp protocols. We speculate that the location of Kv4.3 channels on dendrites, together with a window current for IA at rest, serves to regulate excitatory afferent inputs.NEW & NOTEWORTHY Here, we demonstrate that the transient outward K+ current IA occurs in both GABAergic and non-GABAergic neurons via Kv4.3 channels in the rostral (gustatory) solitary nucleus. Although found in both cell types, IA is more prevalent in non-GABAergic cells; a larger conductance at more negative potentials leads to a greater impact on spike initiation compared with GABAergic neurons. An IA window current further suggests that IA can regulate excitatory afferent input to the nucleus.

Display colour scale effects on diagnostic performance and reader agreement in cardiac CT and prostate apparent diffusion coefficient assessment.

AIM: To investigate the effect of colour scale choice on diagnostic performance in the interpretation of medical images. MATERIALS AND METHODS: Twelve clinicians interpreted 210 myocardial computed tomography (CT) perfusion (CTP) examinations, and nine clinicians interpreted 165 magnetic resonance imaging (MRI) apparent diffusion coefficient (ADC) prostate images. In three separate sessions, each participant read the same image set using greyscale, hot-iron, and rainbow scales, respectively. Participants scored their level of confidence for tumour presence in the ADC study, and for ischaemia in the CTP study, from 0 to 100. The area under the receiver operating characteristic (ROC) curve (AUC) was used as the performance metric. For cases that scored >50, CTP readers' agreement on the ischaemic transmural extent was analysed, and ADC map readers' selected values and coordinates for the lowest ADC within the detected tumour were compared across different colour scales. RESULTS: For CTP detection, the AUC was up to 0.10 higher with greyscale, 0.67±0.02 (standard error), compared to rainbow, 0.56±0.02, and detection with hot-iron was in between (0.61±0.03). For ischaemic transmural lesion categorisation, observed inter-reader agreement was highest with greyscale for category 25-50%. There is a small tendency for rainbow and greyscale to outperform hot-iron in the detection of prostate tumours. The selected lowest ADC value and pixel localisation was similar with all colour scales. CONCLUSIONS: The present findings suggest that colour visualisation has a measurable effect on CTP and ADC performance. Further investigation is necessary to determine the magnitude of the effect in diagnostic tasks.

Warming experiments underpredict plant phenological responses to climate change.

Warming experiments are increasingly relied on to estimate plant responses to global climate change. For experiments to provide meaningful predictions of future responses, they should reflect the empirical record of responses to temperature variability and recent warming, including advances in the timing of flowering and leafing. We compared phenology (the timing of recurring life history events) in observational studies and warming experiments spanning four continents and 1,634 plant species using a common measure of temperature sensitivity (change in days per degree Celsius). We show that warming experiments underpredict advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. For species that were common to both study types, the experimental results did not match the observational data in sign or magnitude. The observational data also showed that species that flower earliest in the spring have the highest temperature sensitivities, but this trend was not reflected in the experimental data. These significant mismatches seem to be unrelated to the study length or to the degree of manipulated warming in experiments. The discrepancy between experiments and observations, however, could arise from complex interactions among multiple drivers in the observational data, or it could arise from remediable artefacts in the experiments that result in lower irradiance and drier soils, thus dampening the phenological responses to manipulated warming. Our results introduce uncertainty into ecosystem models that are informed solely by experiments and suggest that responses to climate change that are predicted using such models should be re-evaluated.

Inhibitory modulation of optogenetically identified neuron subtypes in the rostral solitary nucleus.

Inhibition is presumed to play an important role in gustatory processing in the rostral nucleus of the solitary tract (rNST). One source of inhibition, GABA, is abundant within the nucleus and comes both from local, intrasolitary sources and from outside the nucleus. In addition to the receptor-mediated effects of GABA on rNST neurons, the hyperpolarization-sensitive currents, Ih and IA, have the potential to further modulate afferent signals. To elucidate the effects of GABAergic modulation on solitary tract (ST)-evoked responses in phenotypically defined rNST neurons and to define the presence of IA and Ih in the same cells, we combined in vitro recording and optogenetics in a transgenic mouse model. This mouse expresses channelrhodopsin 2 (ChR2) in GAD65-expressing GABAergic neurons throughout the rNST. GABA positive (GABA+) neurons differed from GABA negative (GABA-) neurons in their response to membrane depolarization and ST stimulation. GABA+ neurons had lower thresholds to direct membrane depolarization compared with GABA- neurons, but GABA- neurons responded more faithfully to ST stimulation. Both IA and Ih were present in subsets of GABA+ and GABA- neurons. Interestingly, GABA+ neurons with Ih were more responsive to afferent stimulation than inhibitory neurons devoid of these currents, whereas GABA- neurons with IA were more subject to inhibitory modulation. These results suggest that the voltage-gated channels underlying IA and Ih play an important role in modulating rNST output through a circuit of feedforward inhibition.

112 What's your emergency? Overview of mental health and sleep disorders among emergency medical dispatchers in a French 112 call center.

BACKGROUND: Emergency medical dispatchers (EMD) experience significant occupational stress. Medical dispatching includes call-taking, triage, dispatch, and providing callers gesture guidance to the victims. Every decision has a major impact on the patient's outcome. Chronic exposure to stress and potentially traumatic situations, combined with night shifts can impact the stress response and physical health of staff. OBJECTIVES: To evaluate the prevalence of mental health and sleep disorders among EMD personnel working in a 112-call center, prior to an evidence-based prevention intervention (primary outcome); and to assess the relationship between health outcomes and DM (secondary outcome). METHODS: We conducted a descriptive, monocentric study with 109 EMD. HAD Anxiety (HAD-A) and Depression (HAD-D) scores, and the PTSD checklist for DSM-5 (PCL-5) were used to explore mental health disorders. The Epworth Sleepiness Scale, and other analog scales were used to explore sleep disorders. DM resources were assessed using the Freiburg Mindfulness Inventory (FMI), and its Presence and Acceptance subscales. RESULTS: A total of 72% of the EMD working in the call center were included. Of these, 16.6% had moderate anxiety disorder, and 6.4% had an anxiety disorder (Mean HAD-A: 6.05 ± 2.88). Furthermore, 16.6% had a moderate depression disorder, and 6.4% had a depression disorder (Mean HAD-D: 4.28 ± 3.28), and 16% had symptoms of PTSD (Mean PCL-5: 17.57 ± 13.67). Turning to sleep, 39% may suffer from excessive daytime sleepiness (EDS), and 10% had confirmed EDS (Mean Epworth score 10.47 ± 4.41). Finally, 39% had moderate insomnia, and 59% had severe insomnia (Mean insomnia: 13.84 ± 5.77.). Medium-strength negative correlations were found between mental health and DM (FMI scores and sub-scores: -0.48 < r < - 0.29; 0.001 < p < 0.004); and a positive correlation was found between DM and daytime awareness (0.22 < r < 0.26; 0.01 < p < 0.03). CONCLUSION: The prevalence of depression, symptoms of PTSD, and sleep disorders in our sample of EMD is significant, and confirms findings reported in the literature. The EMD population may benefit from specific, multi-level interventions that target mindfulness, sleep, and ergonomics to improve their mental and physical health.

Retrospective analysis of tranexamic acid administration in French war-wounded between October 2016 and September 2020.

INTRODUCTION: Since 2013, the French Army Health Service, in agreement with international experts, has recommended the administration of 1 g of tranexamic acid (TXA) in trauma patients in haemorrhagic shock or at risk of bleeding within 3 hours of the trauma. METHODS: The aim of this analysis was to describe the administration of TXA in French military personnel wounded during military operations in the Sahelo-Sahelian band between October 2016 and September 2020. Data were collected from forward health records and hospital data from the French hospital where the casualty was finally evacuated. Underuse of TXA was defined as the lack of administration in casualties who had received a blood transfusion with one or more of red blood cells, low-titre whole blood or French lyophilised plasma within the first 24 hours of injury and overuse as its administration in the non-transfused casualty. RESULTS: Of the 76 patients included, 75 were men with an average age of 28 years. Five patients died during their management. 19 patients received TXA (25%) and 16 patients were transfused (21%). Underuse of TXA occurred in 3 of the 16 patients (18.8%) transfused. Overuse occurred in 6 of 60 (10%) non-transfused patients. CONCLUSION: The analysis found an important underuse of TXA (almost 20%) and highlighted the need for optimising the prehospital clinical practice guidelines to aid prehospital medical practitioners more accurately in administering TXA to casualties that will require blood products.

Regulation of Rostral Nucleus of the Solitary Tract Responses to Afferent Input by A-type K+ Current.

Responses in the rostral (gustatory) nucleus of the solitary tract (rNST) are modified by synaptic interactions within the nucleus and the constitutive membrane properties of the neurons themselves. The potassium current IA is one potential source of modulation. In the caudal NST, projection neurons with IA show lower fidelity to afferent stimulation compared to cells without. We explored the role of an A-type K+ current (IA) in modulating the response to afferent stimulation and GABA-mediated inhibition in the rNST using whole cell patch clamp recording in transgenic mice that expressed channelrhodopsin (ChR2 H134R) in GABAergic neurons. The presence of IA was determined in current clamp and the response to electrical stimulation of afferent fibers in the solitary tract was assessed before and after treatment with the specific Kv4 channel blocker AmmTX3. Blocking IA significantly increased the response to afferent stimulation by 53%. Using dynamic clamp to create a synthetic IA conductance, we demonstrated a significant 14% decrease in responsiveness to afferent stimulation in cells lacking IA. Because IA reduced excitability and is hyperpolarization-sensitive, we examined whether IA contributed to the inhibition resulting from optogenetic release of GABA. Although blocking IA decreased the percent suppression induced by GABA, this effect was attributable to the increased responsiveness resulting from AmmTX3, not to a change in the absolute magnitude of suppression. We conclude that rNST responses to afferent input are regulated independently by IA and GABA.

Evolution of military evacuation activity in French Guiana over 10 years: a retrospective observational study.

BACKGROUND: Three permanent military operations are established in French Guiana. The Cayenne medical unit is a French military search and rescue unit and provides MEDEVAC and CASEVAC for ill and injured soldiers. The main objective of this study was to describe the temporal trends of its evacuation missions over 10 years. The secondary purpose was to document the means used for these missions. METHODS: This retrospective observational study included patients who were evacuated for a medical reason or an injury during military operations in French Guiana. We collected the data from the computerised registers the medical department had stored. RESULTS: From 1 January 2010 to 31 December 2019, 1070 patients were included, representing a median annual incidence of 115 (IQR 91-122) evacuations. Of these, 602 (59%) were evacuated by helicopter, 214 (21%) by airplane, 182 (18%) by ambulance and 19 (2%) by pirogue.Reasons for evacuation were diseases in 664 (62%) patients, non-battle injuries in 389 (36%) patients and battle injuries in 17 (2%) patients. Finally, 286 (29%) evacuations were MEDEVAC and 712 (71%) were CASEVAC.Over the years, the increasing number of evacuations reached a maximum of 183 in 2018. Helicopter evacuations, once the primary mode of evacuation, have declined proportionately in favour of other means of evacuation. CONCLUSION: Evacuation missions by the Cayenne medical unit increased over the 10-year study period, while helicopter use decreased. This evolution is a response to the constraints of adapting military operations to fight against illegal gold mining in the Amazonian Forest. Improvement of the means and procedures allows provision of the best care to patients while ensuring the ongoing conduct of military operations.

Relatedness of Macrophomina phaseolina isolates from tallgrass prairie, maize, soybean and sorghum.

Agricultural and wild ecosystems may interact through shared pathogens such as Macrophomina phaseolina, a generalist clonal fungus with more than 284 plant hosts that is likely to become more important under climate change scenarios of increased heat and drought stress. To evaluate the degree of subdivision in populations of M. phaseolina in Kansas agriculture and wildlands, we compared 143 isolates from maize fields adjacent to tallgrass prairie, nearby sorghum fields, widely dispersed soybean fields and isolates from eight plant species in tallgrass prairie. Isolate growth phenotypes were evaluated on a medium containing chlorate. Genetic characteristics were analysed based on amplified fragment length polymorphisms and the sequence of the rDNA-internal transcribed spacer (ITS) region. The average genetic similarity was 58% among isolates in the tallgrass prairie, 71% in the maize fields, 75% in the sorghum fields and 80% in the dispersed soybean fields. The isolates were divided into four clusters: one containing most of the isolates from maize and soybean, two others containing isolates from wild plants and sorghum, and a fourth containing a single isolate recovered from Solidago canadensis in the tallgrass prairie. Most of the sorghum isolates had the dense phenotype on media containing chlorate, while those from other hosts had either feathery or restricted phenotypes. These results suggest that the tallgrass prairie supports a more diverse population of M. phaseolina per area than do any of the crop species. Subpopulations show incomplete specialization by host. These results also suggest that inoculum produced in agriculture may influence tallgrass prairie communities, and conversely that different pathogen subpopulations in tallgrass prairie can interact there to generate 'hybrids' with novel genetic profiles and pathogenic capabilities.

Pediatric victims involved in urban fires in Paris and its suburbs: Epidemiology, prehospital care, and lessons learned.

AIM: The literature includes few reports on the prehospital care of pediatric casualties of urban house fires. Here we aimed to describe the epidemiology of pediatric fire victims, focusing on their injuries, prehospital care, and survival. METHODS: This retrospective study included children under 15 years of age who were victims of urban house fires and who received care from prehospital medical teams. The variables analyzed included epidemiology, specific care provided by prehospital emergency services, the number of cardiac arrests, and survival rates. RESULTS: Over the 15-month study period, 365 house fires required the presence of at least one prehospital medical team. Casualties of these fires included 121 pediatric victims (median age, 4 years [interquartile range: 2-9 years]). All children were initially treated by a prehospital medical team that was not specialized in pediatrics. Six children (4.9%) received secondary treatment from a pediatric support team. Of the 121 children, 114 (94.2%) suffered from smoke inhalation and seven (5.8%) from burns. Two patients who were in cardiac arrest at their initial medical care did not survive. CONCLUSION: Pediatric fire casualties were initially managed by prehospital medical teams that were not specialized in pediatrics. As in adults, the main injuries were secondary to smoke inhalation, but this has increased toxicity in children. Prehospital teams not specialized in pediatrics can optimize their practice via the sharing of experiences, team training, and cognitive aid checklist for pediatric fire victims.

Is E-FAST possible and useful on the battlefield? A feasibility study during medical courses in hostile environment (MEDICHOS): preliminary results.

INTRODUCTION: The extent of the French forces' territory in the Sahel band generates long medical evacuations. In case of many victims, to respect the golden hour rule, first-line sorting is essential. Through simulation situations, the aim of our study was to assess whether the use of ultrasound was useful to military doctors. METHODS: In combat-like exercise conditions, we provided trainees with a pocket-size ultrasound. Every patient for whom the trainees chose to perform ultrasound in role 1 was included. An extended focused assessment with sonography for trauma (E-FAST) was performed with six basic sonographic views. We evaluated whether these reference views were obtained or not. Once obtained by the trainees, pathological views corresponding to the scenario were shown to assess whether the trainees modified their therapeutic management strategy and their priorities. RESULTS: 168 patients were treated by 15 different trainee doctors. Of these 168 patients, ultrasound (E-FAST or point-of-care ultrasound) was performed on 44 (26%) of them. In 51% (n=20/39) of the situations, the practitioners considered that the realisation of ultrasound had a significant impact in terms of therapeutic and evacuation priorities. More specifically, it changed therapeutic decisions in 67% of time (n=26/39) and evacuation priorities in 72% of time (n=28/39). CONCLUSION: This original work showed that ultrasound on the battlefield was possible and useful. To confirm these results, ultrasound needs to be democratised and assessed in a real operational environment.

Climate change effects on plant disease: genomes to ecosystems.

Research in the effects of climate change on plant disease continues to be limited, but some striking progress has been made. At the genomic level, advances in technologies for the high-throughput analysis of gene expression have made it possible to begin discriminating responses to different biotic and abiotic stressors and potential trade-offs in responses. At the scale of the individual plant, enough experiments have been performed to begin synthesizing the effects of climate variables on infection rates, though pathosystem-specific characteristics make synthesis challenging. Models of plant disease have now been developed to incorporate more sophisticated climate predictions. At the population level, the adaptive potential of plant and pathogen populations may prove to be one of the most important predictors of the magnitude of climate change effects. Ecosystem ecologists are now addressing the role of plant disease in ecosystem processes and the challenge of scaling up from individual infection probabilities to epidemics and broader impacts.

Damage control: Concept and implementation.

The concept of damage control (DC) is based on a sequential therapeutic strategy that favors physiological restoration over anatomical repair in patients presenting acutely with hemorrhagic trauma. Initially described as damage control surgery (DCS) for war-wounded patients with abdominal penetrating hemorrhagic trauma, this concept is articulated in three steps: surgical control of lesions (hemostasis, sealing of intestinal spillage), physiological restoration, then surgery for definitive repair. This concept was quickly adapted for intensive care management under the name damage control resuscitation (DCR), which refers to the modalities of hospital resuscitation carried out in patients suffering from traumatic hemorrhagic shock within the context of DCS. It is based mainly on specific hemodynamic resuscitation targets associated with early and aggressive hemostasis aimed at prevention or correction of the lethal triad of hypothermia, acidosis and coagulation disorders. Concomitant integration of resuscitation and surgery from the moment of admission has led to the concept of an integrated DCR-DCS approach, which enables initiation of hemostatic resuscitation upon arrival of the injured person, improving the patient's physiological status during surgery without delaying surgery. This concept of DC is constantly evolving; it stresses management of the injured person as early as possible, in order to initiate hemorrhage control and hemostatic resuscitation as soon as possible, evolving into a concept of remote DCR (RDCR), and also extended to diagnostic and therapeutic radiological management under the name of radiological DC (DCRad). DCS is applied only to the most seriously traumatized patients, or in situations of massive influx of injured persons, as its universal application could lead to a significant and unnecessary excess-morbidity to injured patients who could and should undergo definitive treatment from the outset. DCS, when correctly applied, significantly improves the survival rate of war-wounded.

Responsiveness of neurons in the hamster parabrachial nuclei to taste mixtures.

Responses from hamster parabrachial nuclei neurons to stimulation of the anterior tongue with sucrose, NaCl, HCl, quinine hydrochloride, and the six two-component mixtures of these stimuli were recorded. A cell's response to a mixture approached its response to the mixture's more effective component in the majority of cases, but was sometimes greater or smaller than this response. The best predictor of a neuron's response to a mixture, then, was its response to the mixture's more effective component. The single-component stimulus producing the maximum response was determined for each neuron and the response to this stimulus was compared with the responses evoked by the six mixtures. For 30% of the cells, a mixture elicited a response reliably, but only 1.1-2.1 times greater than the response to the best single-component stimulus. Thus, there were no neurons specialized to respond to these mixtures. The across-neuron patterns elicited by mixtures and the responses of best-stimulus classes to mixtures were studied for comparison with psychophysical data on taste mixtures. Mixtures were usually correlated with single-component stimuli in the mixture, but not with stimuli not in the mixture. In fact, five of the six mixtures fell directly between their components in a multidimensional scaling plot. In addition, a mixture was most effective in stimulating only those classes of neurons maximally stimulated by the mixture's components. These results correlate with psychophysical data suggesting that mixtures of taste stimuli evoke the same taste qualities as evoked by the mixture's components.

Effects of high-fat diet and gastric bypass on neurons in the caudal solitary nucleus.

Bariatric surgery is an effective treatment for obesity that involves both peripheral and central mechanisms. To elucidate central pathways by which oral and visceral signals are influenced by high-fat diet (HFD) and Roux-en-Y gastric bypass (RYGB) surgery, we recorded from neurons in the caudal visceral nucleus of the solitary tract (cNST, N=287) and rostral gustatory NST (rNST,N=106) in rats maintained on a HFD and lab chow (CHOW) or CHOW alone, and subjected to either RYGB or sham surgery. Animals on the HFD weighed significantly more than CHOW rats and RYGB reversed and then blunted weight gain regardless of diet. Using whole-cell patch clamp recording in a brainstem slice, we determined the membrane properties of cNST and rNST neurons associated with diet and surgery. We could not detect differences in rNST neurons associated with these manipulations. In cNST neurons, neither the threshold for solitary tract stimulation nor the amplitude of evoked EPSCs at threshold varied by condition; however suprathreshold EPSCs were larger in HFD compared to chow-fed animals. In addition, a transient outward current, most likely an IA current, was increased with HFD and RYGB reduced this current as well as a sustained outward current. Interestingly, hypothalamic projecting cNST neurons preferentially express IA and modulate transmission of afferent signals (Bailey, '07). Thus, diet and RYGB have multiple effects on the cellular properties of neurons in the visceral regions of NST, with potential to influence inputs to forebrain feeding circuits.

Gender and Tanner stage differences in body composition and insulin sensitivity in early pubertal children.

A cross-sectional analysis examining the impact of gender and early pubertal stage on insulin sensitivity (Si) and body composition was carried out as part of a longitudinal study to determine how Si relates to body composition changes during puberty. The study population consisted of 97 healthy children (age range, 9.7-14.5 yr; 28 Tanner stage 2 boys, 25 stage 3 boys, 22 Tanner stage 2 girls, and 22 stage 3 girls). Si was determined by the modified minimal model of Bergman. Body fatness was assessed by body mass index (BMI), skinfold thickness, hydrodensitometry, and bioelectrical impedance. Results showed that stage 3 girls and stage 2 boys had significantly more body fat than stage 2 girls and stage 3 boys. Si was significantly lower (P < 0.02) and insulin-like growth factor-I levels higher (P < 0.006) in stage 3 girls compared to those in the other 3 groups. The best predictor of Si in all subjects was BMI (r2 = -0.63; P < 0.0001). In a stepwise multiple regression analysis, Si was best predicted from BMI, gender, and Tanner stage. According to this model, Si decreased as BMI increased and was lower in girls and Tanner stage 3 children. In boys, Si was best predicted from total fat mass and Tanner stage. In girls, Si correlated inversely with BMI, parental obesity, and insulin-like growth factor-I levels. Neither testosterone nor estradiol levels were associated with Si. These results demonstrate that Si, like body composition, has gender-dependent changes during puberty. It is, thus, possible that these pubertal changes in Si relate to changes in body composition.

Insulin-like growth factor binding protein-I levels are strongly associated with insulin sensitivity and obesity in early pubertal children.

In conditions associated with insulin resistance, insulin-like growth factor binding protein-I (IGFBP-I) levels have been shown to correlate inversely with insulin levels. Puberty is associated with insulin resistance and thus provides a model for comparing the relationship of IGFBP-I to both insulin levels and measures of insulin sensitivity. Our study population consisted of 104 healthy pubertal children, age 9.8-14.6 yr. Each subject had his/her insulin sensitivity (Si) assessed by the modified minimal model of Bergman, which employs a frequently sampled i.v. glucose tolerance test. Results showed that IGFBP-I levels were significantly higher in boys than in pubertally matched girls (P < 0.01). There was a strong positive correlation between IGFBP-I levels and Si (r = 0.65, P < 0.0001) and a weaker negative correlation with fasting insulin levels (r = -0.38, P < 0.0001). An inverse relationship was also found between IGFBP-I levels and body mass index (r = -0.46, P < 0.0001) and with IGF-I levels (girls only, r = -0.41, P < 0.003). Consequently, insulin sensitivity, obesity, and IGF-I are important predictors of IGFBP-I levels in pubertal children. It is possible that insulin-mediated suppression of IGFBP-I in obese children may increase free IGF-I levels and thus contribute to somatic growth. The same mechanism may operate in pubertal children, where insulin resistance and growth acceleration occur simultaneously.

Trade-offs between male and female reproduction associated with allozyme variation in phosphoglucoisomerase in an annual plant (Clarkia unguiculata: Onagraceae).

The genotype of an individual for allozymes such as phosphoglucoisomerase (Pgi) is often not neutral with regard to fitness. Studies of several taxa have found consistent fitness differences among Pgi genotypes expressing different allozymes. We conducted a greenhouse experiment with Clarkia unguiculata to determine whether allelic variation at the Pgi-C1 locus may affect components of male and female function. We found significant differences in siring success between pollen donors homozygous for different Pgi alleles. When a mixture of pollen was applied to stigmas under conditions of gametophytic competition (more pollen deposited on stigmas than there are ovules available to fertilize), donors homozygous for the C allele of Pgi sired more seeds per fruit than B-allele donors. Differences between genotypes with respect to female fertility per fruit contrasted with the male advantage associated with the C allele. Recipients homozygous for the C allele produced fruits with more aborted seeds and fewer viable seeds than recipients homozygous for the B allele. These results suggest that allelic variation at a single locus may have opposing effects on male and female reproductive success in C. unguiculata, and that trade-offs between the two types of reproductive success could contribute to the maintenance of variation at the Pgi-C1 locus.