Social skills in neurodevelopmental disorders: a study using role-plays to assess adolescents and young adults with 22q11.2 deletion syndrome and autism spectrum disorders

BACKGROUNDS

Social skills are frequently impaired in neurodevelopmental disorders and genetic conditions, including 22q11.2 deletion syndrome (22q11DS) and autism spectrum disorders (ASD). Although often assessed with questionnaires, direct assessment provides a more valid estimate of the constructs. Role-plays (i.e., simulates situational settings) therefore appear to be an appropriate indicator of social skills in daily life.

METHODS

This co-registered study involved 53 individuals with 22q11DS, 34 individuals with ASD, and 64 typically developing (TD) peers aged 12-30 years. All participants were assessed with role-plays as well as parent-reported questionnaires and clinical interviews focusing on social skills, functioning and anxiety.

RESULTS

Both clinical groups showed impaired social skills compared to TD, but distinct social profiles emerged between the groups. Individuals with 22q11DS displayed higher social appropriateness and clarity of speech but weaker general argumentation and negotiation skills, with the opposite pattern observed in participants with ASD. No association was found between social skills measured by direct observation and caregiver reports. Social anxiety, although higher in clinical groups than in TD, was not associated with role-plays.

CONCLUSIONS

This study highlights the need to train social skills through tailored interventions to target the specific difficulties of each clinical population. It also highlights the importance of combining measures as they do not necessarily provide the same outcome.

Cognitive emotion regulation difficulties increase affective reactivity to daily-life stress in autistic adolescents and young adults

LAY ABSTRACT

Previous research has shown that autistic individuals report high levels of perceived stress and have an increased likelihood of developing mental health difficulties. Increase in individuals' negative emotions in relation to perceived stress (i.e. affective reactivity to stress) is a known risk factor for mental health difficulties. In this study, we investigated perceived daily stress and affective reactivity to stress in autistic (n = 39, age = 18.4) and non-autistic (n = 55, age = 18.1) adolescents and young adults. We used the ecological momentary assessment, a technique that allows to assess individuals repeatedly in their daily life using their smartphone. Moreover, participants filled a questionnaire to evaluate the strategies they use to regulate emotions when faced with difficulties. Finally, a clinical interview and a parent-report questionnaire were used to assess mental health symptoms. Autistic youth reported higher levels of perceived daily stress compared with non-autistic peers. Moreover, they showed increased affective reactivity to stress related to their daily activities. Autistic participants reported more emotion regulation difficulties (e.g. more repetitive thinking of difficulties) compared with non-autistic participants. Difficulties in emotion regulation increased negative emotions in relation to stress and might contribute to the severity of mental health symptoms. We conclude that adolescents and young adults with autism report high perceived stress in their daily lives. To minimize the negative impact of stress and the development of mental health symptoms, people supporting autistic young people could focus on stress management skills and the strategies that the youth use to manage emotions.

Increased affective reactivity to daily social stressors is associated with more severe psychotic symptoms in youths with 22q11.2 deletion syndrome

BACKGROUND

Increased reactivity to minor stressors is considered a risk factor for psychosis, especially in vulnerable individuals. In the present study, we investigated affective and psychotic stress reactivity as well as its link with psychotic symptoms and psychopathology in youths with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with a high risk for psychosis.

METHODS

A 6-day ecological momentary assessment protocol was used to assess perceived daily-life stress as well as affective and psychotic reactivity to stress in participants with 22q11DS (n = 38, age = 18.4) and healthy controls (HC; n = 53, age = 19.1). Psychotic symptoms, general psychopathology, and coping strategies were also assessed through clinical interviews and questionnaires.

RESULTS

Participants with 22q11DS reported higher levels of perceived social stress (b = 0.21, p = 0.036) but lower levels of activity-related stress (b = -0.31, p = 0.003) in their daily lives compared to HC. The groups did not differ in affective or psychotic reactivity to stress, but individuals with 22q11DS who reported increased affective reactivity to social stressors showed more severe positive psychotic symptoms (rs = 0.505, p = 0.008). Finally, avoidance coping strategies moderated the association between stress and negative affects.

CONCLUSIONS

Our results suggest an increased vulnerability for daily social stress in youths with 22q11DS, and link elevated social stress reactivity to heightened psychotic symptom severity. Given the high risk for psychosis in 22q11DS, interventions should focus on reducing social stress and developing adaptive coping strategies.

Characterizing Daily-Life Social Interactions in Adolescents and Young Adults with Neurodevelopmental Disorders: A Comparison Between Individuals with Autism Spectrum Disorders and 22q11.2 Deletion Syndrome

Social impairments are common features of 22q11.2 deletion syndrome (22q11DS) and autism spectrum disorders (ASD). The Ecological Momentary Assessment (EMA) allowed access to daily-life information in order to explore the phenomenology of social interactions. 32 individuals with 22q11DS, 26 individuals with ASD and 44 typically developing peers (TD) aged 12-30 were assessed during 6 days 8 times a day using a mobile app. Participants with 22q11DS and ASD did not spend more time alone but showed distinct implication in the social sphere than TD. Distinct profiles emerged between the two conditions regarding the subjective experience of aloneness and the subjective experience of social interactions. This study highlights distinct social functioning profiles in daily-life in 22q11DS and ASD that points towards different therapeutic targets.

Exploring associations between diurnal cortisol, stress, coping and psychopathology in adolescents and young adults with 22q11.2 deletion syndrome

Background

22q11.2 deletion syndrome (22q11DS) is a neurogenetic condition associated to a high risk for psychiatric disorders, including psychosis. Individuals with 22q11DS are thought to experience increased levels of chronic stress, which could lead to alterations in hypothalamic-pituitary-adrenocortical (HPA)-axis functioning. In the current study, we investigated for the first time diurnal salivary cortisol profiles in adolescents and young adults with 22q11DS as well as their link with stress exposure, coping strategies and psychopathology, including psychotic symptoms.

Methods

Salivary cortisol was collected from adolescents and young adults with 22q11DS (n = 30, age = 19.7) and matched healthy controls (HC; n = 36, age = 18.5) six times a day for two days. Exposure to stressful life events, including peer victimization, coping strategies and general psychopathology were assessed with questionnaires. Psychotic symptoms and psychiatric comorbidities were evaluated with clinical interviews.

Results

We observed similar daily levels and diurnal profiles of salivary cortisol in adolescents and young adults with 22q11DS compared to HCs. However, participants with 22q11DS reported less frequent exposure to stress than HCs. In 22q11DS, we observed a significant association between the use of non-adaptive coping strategies and the severity of psychotics symptoms. Cortisol level was not associated to severity of psychotic symptoms, but elevated cortisol awakening response (CAR) was found in participants with 22q11DS with higher levels of general psychopathology.

Conclusions

Our results do not support earlier propositions of altered HPA-axis functioning in 22q11DS but highlight the need to further investigate diurnal cortisol as an indicator of HPA-axis functioning and its link with (earlier) stress exposure and psychopathology in this population. Interventions should target the development of adaptive coping skills in preventing psychosis in 22q11DS.

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Adolescents and young adults with 22q11DS report reduced exposure to stress.

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Non-adaptive coping is linked with the severity of psychotic symptoms in 22q11DS.

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Youth with 22q11DS show typical diurnal cortisol profiles.

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Elevated cortisol awakening response is related to greater general psychopathology.

Psychotic experiences in daily-life in adolescents and young adults with 22q11.2 deletion syndrome: An Ecological Momentary Assessment study

22q11.2 deletion syndrome (22q11DS) is a genetic condition associated with a markedly increased risk for psychosis. Psychotic experiences are classically evaluated by clinical interviews that give little information about these symptoms' fluctuation in daily-life. The current study aims to investigate these phenomena using the Ecological Momentary Assessment (EMA), a structured diary technique that collects real-life measures in the everyday-life context, and to examine how these manifestations relate to a gold standard semi-structured assessment of psychotic experiences. Eighty-six individuals with 22q11DS as well as healthy controls (HC) aged 11-27 years were recruited. They completed a 6-day EMA protocol assessing momentary psychotic experiences as well as positive and negative affect. The presence of (attenuated) psychotic symptoms was assessed in 22q11DS participants with the SIPS interview. Participants with 22q11DS reported more intense (p = .005) and more frequent (p = .006) momentary psychotic experiences than HC. Significant associations between negative affect and momentary psychotic experiences were observed in both groups (p = .001). In participants with 22q11DS, more intense (p = <.001) and more frequent (p = <.001) momentary psychotic experiences measured by EMA were associated with the severity of SIPS positive symptoms. Participants with 22q11DS reporting at least attenuated positive symptoms of psychosis on the SIPS had more intense (p = .027) and more frequent (p = .023) momentary psychotic experiences than participants with 22q11DS without psychotic symptoms. This study highlights the validity of EMA to assess psychotic experiences in the context of daily-life and sets correspondence between EMA and the SIPS. Furthermore, it expands our current understanding of the associations between mood and psychotic experiences.

The CoPhyLab comet-simulation chamber

The Comet Physics Laboratory (CoPhyLab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. The project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners, the physics of comets, including the processes inside cometary nuclei, the activity leading to the ejection of dust and gas, and the sub-surface and surface evolution of cometary nuclei when exposed to solar illumination. CoPhyLab will provide essential information on the formation and evolution of comets and insights into the origins of primitive Solar System bodies. To this end, we constructed a new laboratory that hosts several small-scale experiments and a large-scale comet-simulation chamber (L-Chamber). This chamber has been designed and constructed to host ice-dust samples with a diameter of up to 250 mm and a variable height between 100 and 300 mm. The cometary-analog samples will be kept at temperatures below 120 K and pressures around 10^-6 mbar to ensure cometary-like conditions. In total, 14 different scientific instruments are attached to the L-Chamber to study the temporal evolution of the physical properties of the sample under different insolation conditions. Due to the implementation of a scale inside the L-Chamber that can measure weight changes of the samples with high precision, the cooling system is mechanically decoupled from the sample holder and cooling of the samples occurs by radiation only. The constructed chamber allows us to conduct uninterrupted experiments at low temperatures and pressures up to several weeks.

Social cognition in individuals with 22q11.2 deletion syndrome and its link with psychopathology and social outcomes: a review

BACKGROUND

The 22q11.2 deletion syndrome (22q11DS) is a genetic syndrome that results in a highly variable profile of affected individuals of which impairments in the social domain and increased psychopathology are the most prominent. Notably, 25-30% of affected individuals eventually develop schizophrenia/psychosis, predisposing persons with the syndrome to increased risk for this disorder. Because social cognition is considered to underlie social behavior and to be related to psychopathology, this systematic review investigated social cognition in individuals with 22q11DS and examined reported links across its domains with psychopathology and social outcomes. This can provide the basis for a closer understanding of the path from risk to disorder and will inform on the specific domains that can be targeted with preventive intervention strategies.

METHOD

Systematic literature review of studies that reported the links between social cognitive domains and psychopathology and/or social outcomes in individuals with 22q11DS. Electronic databases searched were PubMed and PsycINFO.

RESULTS

Defined eligibility criteria identified a total of ten studies to be included in the present review. Selected studies investigated links between two domains of social cognition (emotion processing and theory of mind (ToM)) and psychopathology and/or social outcomes. With respect to the links to psychopathology, two aspects of social cognition were related primarily to negative symptoms. Results regarding the associations to positive and emotional symptoms (anxiety/depression) are limited and require further investigation. Even though both aspects of social cognition were associated with social outcomes, several studies also found no links between these two domains. Both reports invite for an additional examination of reported results and specific considerations regarding chosen constructs.

CONCLUSION

Although equivocal, results of the present review provide sufficient evidence that social cognition is a useful domain for the closer elucidation of clinical outcomes and social difficulties in this population. At the same time, longitudinal studies and consideration of other variables are also necessary for a timely understanding of affected persons in this respect.

Episodic Future Thinking in Autism Spectrum Disorder and 22q11.2 Deletion Syndrome: Association with Anticipatory Pleasure and Social Functioning

Episodic future thinking (EFT) has been suggested to underlie anticipatory pleasure (AP), itself known to play a crucial role in social functioning (SF). Both AP and SF are impaired in various clinical populations, including autism spectrum disorders (ASD) and 22q11.2 deletion syndrome (22q11DS). Therefore, the relationship between EFT, AP and SF was investigated, as well as the potential role of projecting oneself in a social vs. non-social context. Seventy-seven participants [24 with 22q11DS, 20 with ASD, 33 typically developing controls (TDs)] (aged 12–25) were included. They were assessed with a future thinking task in which they were asked to recall a memory and produce a likely event. Narratives were rated based of specificity, richness and imaginability. Participants completed questionnaires assessing AP and SF. Narratives from ASD and 22q11DS participants were rated as less vivid compared to TDs. However, the characteristics of the narratives differed between ASD and 22q11DS participants in terms of specificity and level of details, as well as in reaction to social condition. Moreover, correlations were found between AP and EFT in both ASD and 22q11DS participants, and between SF and EFT in ASD participants. These results point towards impairments in EFT in both ASD and 22q11DS participants but with a specific profile in each condition. The observed associations between EFT and AP suggest that decreased autonoetic consciousness might underlie AP impairments. In ASD individuals, the association between SF and EFT highlights the need to better characterize EFT since EFT could be another mechanism contributing to social difficulties.

Psycho-social factors associated with mental resilience in the Corona lockdown

The SARS-CoV-2 pandemic is not only a threat to physical health but is also having severe impacts on mental health. Although increases in stress-related symptomatology and other adverse psycho-social outcomes, as well as their most important risk factors have been described, hardly anything is known about potential protective factors. Resilience refers to the maintenance of mental health despite adversity. To gain mechanistic insights about the relationship between described psycho-social resilience factors and resilience specifically in the current crisis, we assessed resilience factors, exposure to Corona crisis-specific and general stressors, as well as internalizing symptoms in a cross-sectional online survey conducted in 24 languages during the most intense phase of the lockdown in Europe (22 March to 19 April) in a convenience sample of N = 15,970 adults. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience (p < 0.0001). The resilience factor PAS also partly mediated the positive association between perceived social support and resilience, and its association with resilience was in turn partly mediated by the ability to easily recover from stress (both p < 0.0001). In comparison with other resilience factors, good stress response recovery and positive appraisal specifically of the consequences of the Corona crisis were the strongest factors. Preregistered exploratory subgroup analyses (osf.io/thka9) showed that all tested resilience factors generalize across major socio-demographic categories. This research identifies modifiable protective factors that can be targeted by public mental health efforts in this and in future pandemics.

A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy

Background

A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC.

Aims

We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy.

Methods

After split-dose preparation, 480 veterans were randomized to AI, WE and CWE.

Results

Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC.

Conclusions

When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

[Impact of quality improvement process upon the state of nutritional support in a critical care unit]

INTRODUCTION

In a preceding article the state of Nutritional support (NS) in an Intensive Care Unit (ICU) was documented [Martinuzzi A et al. Estado del soporte nutricional en una unidad de Cuidados críticos. RNC 2011; 20: 5-17]. In this follow-up work we set to assess the impact of several organizational, recording and educational interventions upon the current state of NS processes.

MATERIALS AND METHODS

Interventions comprised presentation of the results of the audit conducted at the ICU before the institution's medical as well as paramedical personnel; their publication in a periodical, peer-reviewed journal; drafting and implementation of a protocol regulating NS schemes to be carried out at the ICU; and conduction of continuous education activities on Nutrition (such as "experts talks", interactive courses, and training in the implementation of the NS protocol). The state of NS processes documented after the interventions was compared with the results annotated in the preceding article. Study observation window ran between March the 1st, 2011 and May 31th, 2011, both included.

RESULTS

Study series differed only regarding overall-mortality: Phase 1: 40.0% vs. Phase 2: 20.5%; Difference: 19.5%; Z = 1.927; two-tailed-p = 0.054. Interventions resulted in a higher fulfillment rate of the prescribed NS indication; an increase in the number of patients receiving ≥ 80% of prescribed energy; and a reduction in the number of NS lost days. Mortality was (numerically) lower in patients in which the prescribed NS scheme was fulfilled, NS was early initiated, and whom received ≥ 80% of prescribed energy. Adopted interventions had no effect upon average energy intakes: Phase 1: 574.7 ± 395.3 kcal/24 h⁻¹ vs. Phase 2: 591.1 ± 315.3 kcal/24 h⁻¹; two-tailed-p > 0.05.

CONCLUSIONS

Educational, recording and organizational interventions might result in a better conduction of NS processes, and thus, in a lower mortality. Hemodynamic instability is still the most formidable obstacle for initiating and completing NS.

Pattern formation in auxin flux

The plant hormone auxin is fundamental for plant growth, and its spatial distribution in plant tissues is critical for plant morphogenesis. We consider a leading model of the polar auxin flux, and study in full detail the stability of the possible equilibrium configurations. We show that the critical states of the auxin transport process are composed of basic building blocks, which are isolated in a background of auxin depleted cells, and are not geometrically regular in general. The same model was considered recently through a continuous limit and a coupling to the von Karman equations, to model the interplay of biochemistry and mechanics during plant growth. Our conclusions might be of interest in this setting, since, for example, we establish the existence of Lyapunov functions for the auxin flux, proving in this way the convergence of pure transport processes toward the set of equilibrium points.

Historical advances in the study of global terrestrial soil organic carbon sequestration

This paper serves two purposes: it provides a summarized scientific history of carbon sequestration in relation to the soil-plant system and gives a commentary on organic wastes and SOC sequestration. The concept of soil organic carbon (SOC) sequestration has its roots in: (i) the experimental work of Lundegårdh, particularly his in situ measurements of CO2 fluxes at the soil-plant interface (1924, 1927, 1930); (ii) the first estimates of SOC stocks at the global level made by Waksman [Waksman, S.A., 1938. Humus. Origin, Chemical Composition and Importance in Nature, second ed. revised. Williams and Wilkins, Baltimore, p. 526] and Rubey [Rubey, W.W., 1951. Geologic history of sea water. Bulletin of the Geological Society of America 62, 1111-1148]; (iii) the need for models dealing with soil organic matter (SOM) or SOC dynamics beginning with a conceptual SOM model by De Saussure (1780-1796) followed by the mathematical models of Jenny [Jenny, H., 1941. Factors of Soil Formation: a System of Quantitative Pedology. Dover Publications, New York, p. 288], Hénin and Dupuis [Hénin, S., Dupuis, M., 1945. Essai de bilan de la matière organique. Annales d'Agronomie 15, 17-29] and more recently the RothC [Jenkinson, D.S., Rayner, J.H., 1977. The turnover of soil organic matter in some of the Rothamsted classical experiments. Soil Science 123 (5), 298-305] and Century [Parton, W.J., Schimel, D.S., Cole, C.V., Ojima, D.S., 1987. Analysis of factors controlling soil organic matter levels in great plains grasslands. Soil Science Society of America Journal 51 (5), 1173-1179] models. The establishment of a soil C sequestration balance is not straightforward and depends greatly on the origin and the composition of organic matter that is to be returned to the system. Wastes, which are important sources of organic carbon for soils, are taken as an example. For these organic materials the following factors have to be considered: the presence or absence of fossil C, the potential of direct and indirect emissions of non-CO2 greenhouse gases (CH4 and N2O) following application and the agro-system which is being used as a comparative reference.

Problem-solving strategies in dementia patient-caregiver dyads

Examined was the applicability of concepts of the zone of proximal development and scaffolding to the study of dementia. Caregiver-patient dyads were compared to normal elderly dyads in the instructional strategies they used to complete the Block Design subtest of the WAIS-R. Shown by the results was that the use of a detailed behavioral coding scheme was successful in documenting systematic differences between the two groups. Potential use in assessment and intervention is discussed.

Effects of an acute bacterial infection on serum thyroid hormones and nuclear triiodothyronine receptors in mice

Serum T3, T4, and rT3 levels as well as liver nuclear T3 receptors (NT3R) were measured in mice with a bacterial infection. Pseudomonas aeruginosa were injected into one thigh of ICR mice, resulting in a severe infection at sacrifice 15 h later. Since food intake, which influences serum thyroid hormone levels and NT3R, was 75% lower in infected than in control mice, infected mice were either fed and compared with pair-fed controls or fasted and compared with fasted and fed controls. Fasting induced a fall in serum T3 and T4 levels, which was even more pronounced in infected fasted animals. However, while fasting caused an approximately 80% increase in serum rT3 concentrations, serum rT3 levels in infected fasted animals were not different from those in fed controls. The combination of infection and fasting thus prevented the rise in serum rT3 otherwise invariably associated with fasting. NT3R measurements on isolated nuclei revealed the presence of NT3R in mouse liver similar to those reported in rat liver. The NT3R Kd (approximately 2 X 10(-10) M) was not affected by decreased food intake, infection, or a combination thereof. The NT3R maximum binding capacity (MBC) was decreased in fasted animals (460 vs. 306 pg/mg DNA). However, the MBC of infected fasted mice was not different from that of fasted mice. Similarly, no difference in MBC was found between infected fed and pair-fed control mice. In mice injected with heat-killed P. aeruginosa to evaluate potential effects of endotoxins, neither serum thyroid hormone levels nor hepatic NT3R were different from those of controls. These data show that in mice, a severe bacterial infection with P. aeruginosa has effects on serum hormone levels not explained by the disease-associated diminished food intake, whereas it has no effects on liver NT3R beyond those due to the disease-related decreased food intake.

Antibiotic therapy of infections due to Pseudomonas aeruginosa in normal and granulocytopenic mice: comparison of murine and human pharmacokinetics

An effort was made to elucidate the limits of drug-activity tests in small animals. Human plasma kinetics of gentamicin, netilmicin, ticarcillin, ceftazidime, and ceftriaxone were approximated in normal and in granulocytopenic mice infected with various strains of Pseudomonas aeruginosa in the thigh muscle or intraperitoneally. The effect of such dosing on bacterial time-kill curves and on survival was compared with the effect of identical amounts of drug given as a single-bolus injection. With beta-lactams, a highly significant superiority of fractionated dosing (simulated human kinetics) over bolus injections (murine plasma kinetics) was demonstrated, whereas with aminoglycosides it was a single-bolus injection that tended to be more active. Thus, when tested in conventional small-animal models, aminoglycoside activity may be overestimated, whereas beta-lactam activity may be underestimated in respect to humans. These differences found in vivo most probably reflect the different pharmacodynamics between aminoglycosides and beta-lactam drugs (time-kill curves, dose-response curves, and postantibiotic effect) similar to those previously observed in vitro.

Impact of dosing intervals on activity of gentamicin and ticarcillin against Pseudomonas aeruginosa in granulocytopenic mice

The influence of dosing intervals on the activity of gentamicin and ticarcillin against Pseudomonas aeruginosa was studied in vivo. Granulocytopenic mice infected with P. aeruginosa in the thigh muscle were treated with 1-hr or 3-hr injections of gentamicin, ticarcillin, or gentamicin-ticarcillin. Plasma pharmacokinetics of the drugs were correlated with antibacterial activity. Gentamicin injected every 1 hr tended to be less active than gentamicin injected at longer intervals. In contrast, ticarcillin given every 1 hr was significantly more efficacious than equivalent total doses injected every 3 hr. The dosing schedule of gentamicin-ticarcillin was again important for ticarcillin but did not appreciably affect the antibacterial activity of gentamicin. Thus, antimicrobial chemotherapy of P. aeruginosa infections in the granulocytopenic host might be improved by administering ticarcillin rather than gentamicin as a constant infusion.

The effect of prostaglandin F2alpha on corpus luteal function in the rhesus monkey

An experimental model was set up to show whether PGF2alpha caused luteolysis when adequate chorionic gonadotropin was administered. Four mature female rhesus monkeys were studied for two cycles each. HCG was given after ovulation until day 36. PGF2alpha was given on days 28 and 29 in one cycle, while the other served as control. In five out of the total eight cycles studied, the luteal function was maintained up to day 36. However, gradual decline of serum progesterone was noted after days 22 to 26 despite the continuous administration of hCG. Administration of PGF2alpha on days 28 and 29 did not accelerate CL regression. It was also noted that hCG in doses of 500 IU did not maintain CL function in three of four cycles when surgical stress was added.