Genetic characterization of Staphylococcus aureus isolated from Norway rats in Boston, Massachusetts

BACKGROUND

Despite the importance of domesticated animals in the generation and transmission of antibiotic-resistant Staphylococcus aureus, the role of wild animals, specifically rodents, in the ecology of S. aureus remains unclear. We recovered and genotyped S. aureus isolates from wild Norway rats (Rattus norvegicus) in Boston, Massachusetts to examine genetic relationships between common human and animal S. aureus isolates in a large US metropolitan area.

METHODS

We collected and necropsied 63 rats from June 2016 to June 2017. Nasal, foot pad, fur, and fecal swabs were collected. Staphylococcus aureus was isolated using culture-based methods and polymerase chain reaction confirmation. S. aureus isolates were spa typed, tested for antibiotic susceptibility, and whole genome sequenced. Assembled sequences were uploaded to the Comprehensive Antibiotic Resistance Database to identify antibiotic resistance elements. A phylogenetic tree was constructed using the neighbor-joining method with the maximum composite likelihood distance in MEGA7.

RESULTS

We recovered 164 Gram-positive bacterial isolates from Norway rats. Nineteen isolates from eight individual rats were confirmed as S. aureus (prevalence: 12.9% (8/63)). All S. aureus isolates were methicillin-susceptible S. aureus (MSSA), pvl-negative, and resistant to penicillin. Two isolates displayed resistance to erythromycin. Four different S. aureus spa types were detected (t933, t10751, t18202, and t189). Thirteen unique antibiotic resistance elements were identified, and all isolates shared genes mepR, mgrA, arlR, and S. aureus norA. Phylogenetic analysis if the 19 S. aureus isolates revealed they were genetically similar to four clades of S. aureus with similar resistance gene profiles isolated from both human- and animal-derived S. aureus, as well as formed a distinct phylogenetic cluster composed only of rat isolates.

CONCLUSIONS

Wild rodents may serve as a reservoir or vector of antibiotic resistance genes in the urban environment with relevance for human and animal health.

Using the Women Empowerment in Livestock Index (WELI) to Examine Linkages between Women Smallholder Livestock Farmers’ Empowerment and Access to Livestock Vaccines in Machakos County of Kenya: Insights and Critiques

Livestock diseases are a major barrier to productivity for both male and female livestock keepers in Africa. In Kenya, two of the most devastating livestock diseases are Newcastle Disease (ND) in poultry and Contagious Caprine Pleuropneumonia (CCPP) in goats. Female livestock keepers tend to own more small ruminants (goats, sheep, etc.) and poultry and their livelihoods are adversely affected if their herds are not vaccinated against these diseases. Livestock farming has gender specific challenges and opportunities, with implications for the empowerment of women smallholder farmers, their household well-being, food security, and livelihoods. There is a need to estimate the level to which women benefit personally, socially, and economically from keeping livestock, yet there are very few studies that can measure if livestock production does in fact empower women smallholder livestock farmers. This study was done to examine linkages between women’s empowerment and access and control over livestock products and vaccines. The Women Empowerment in Livestock Index (WELI) tool, which was customized to include questions on livestock vaccine access, was used to capture baseline data on empowerment scores for women in Machakos county, Kenya, prior to implementation of animal health and vaccine test models. In total, 400 participants were surveyed in two wards of Machakos County, Kola and Kalama, which were purposively selected. Women’s empowerment was mapped to three domains (3DE): intrinsic agency (power within), instrumental agency (power to), and collective agency (power with) measured against adequacy in 13 indicators. Our results indicate that the household structure (female headed or dual headed household), age of respondents and number of members in a household influence the adequacy score. Work balance was the most significant negative contributor to women’s disempowerment. Women contributed the most to livestock productive activities and attained adequacy in this area compared to men, directly impacting the WELI score. Women smallholder livestock farmers report low CCPP and ND vaccination rates, minimal knowledge on livestock diseases, a lack of access to cold chain storage and rarely visited veterinarians. The WELI score was 0.81 indicating a high level of empowerment for women in this community compared to men leading us to conclude that the overall WELI score was not an accurate indicator of women‘s empowerment in Machakos County. However, the decomposability of the index allows us to disaggregate the drivers of change and to examine how individual indicators contribute to disempowerment.

Deep proteome profiling of mature and reticulated platelets in patients with chronic coronary syndrome using mass cytometry

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the German Center for Cardiovascular

Research (DZHK grant number Deutsches Zentrum für Herz-

Kreislaufforschung 81 × 3600606 to D.B.).

Abstract:

Background/Introduction

Reticulated platelets (RPs) are prothrombotic RNA-rich platelets suggested to be detrimental in patients with chronic coronary syndrome (CCS) and high on treatment platelet reactivity. In addition, circulating RPs levels are independent predictor for adverse cardiovascular events in CCS patients and other pathological settings. However, RPs biology still need to be investigated.

Purpose

We thought to investigate the RPs proteome on single-cell level at rest and after activation using time-of-flight mass cytometry (CyTOF).

Method

Thrombocytes from peripheral blood of 11 CCS patients were isolated, prepared for CyTOF and stained with a custom-made CyTOF-antibody panel of 20 antibodies targeting important transmembrane proteins (anti-CD9, anti-CD29, anti-CD31, anti-CD36-, anti-CD40, anti-CD41, anti-CD42a, anti-CD42b-, anti-CD47, anti-CD61, anti-CD62P-, anti-CD63, anti-CD69, anti-CD107a, anti-CD154, anti-GPVI, anti-GPIIbIIa complex, anti-Par1, anti-PEAR-1 and the negative control anti-CD3 coupled with different metal isotopes). Two samples were prepared from each patient: one baseline sample (non-stimulated platelets) and one sample stimulated with 10 μM thrombin receptor-activating peptide (TRAP). According to previous experiences and common practice, we detected RPs and mature platelets (MPs) based on their RNA content. We analyzed the results with a custom bioinformatic pipeline comparing RPs to MPs expression. Earth mover’s distance (EMD) was assed as a measure of differential expression.

Results

While our bioinformatic analysis revealed that all transmembrane markers are significantly higher expressed in the larger RPs compared to MPs, not all markers differ to the same extend. Interestingly, the four markers with the highest calculated EMD (values in brackets) are all key regulators of platelet activation and aggregation: the collagen receptor GPVI (34.18), the collagen integrin receptor unit CD29 (ITGB1: 33.17), the adhesion protein CD9 (32.94) and the von Willebrand receptor unit CD42b (GPIbalpha) (30.08) (Figure 1A).

Regarding the activation marker expression upon TRAP stimulation, RPs show higher median signal intensities of all four activation markers compared to MPs (Figure 1B and C). Especially, the markers CD107a (LAMP-1) and CD154 (CD40L) are expressed in MPs only to a very low extend, whereas there is a clear overexpression in RPs.

Conclusion

This dataset provides the first high resolution analysis of RPs proteome at rest and upon activation. The pro-thrombotic profile of RPs explains their hyperactivity and could offer the first biomolecular explanation of the detrimental role of RPs in CCS patients. In addition, this dataset provide high resolution biomolecular information which could be useful to personalize antiplatelet therapy in patients with high RPs levels.

AB0646 G- CSF treatment for refractory digital ulcers in systemic sclerosis

Background

Digital ulcers (DU) are a common manifestation of systemic sclerosis (SSc). Despite combination vasodilator therapy, refractory DU are not rare. Granulocyte-colony stimulating factor (G-CSF) had not been evaluated for SSc DU heretofore.

Objectives

To evaluate the efficacy and safety of G-CSF for refractory SSc DU.

Methods

Adult SSc patients with chronic resistant DU despite treatment with maximal tolerated doses of prostacyclin analogue, endothelin receptor antagonist and PDE5 inhibitor, were treated with three consecutive daily doses of G-CSF. Evaluation of DU healing, DUCAS score, antibiotics use, side effects and hospitalizations, was performed.

Results

Ten patients (90% females), mean age 53.5 ± 11.1 years were treated. Fifty percent of the patients had a diffuse SSc disease. All patients suffered from chronic (80%), or recurrent (20%) DU. G-CSF treatment resulted in complete resolution of most DU, after an average of 1.57± 0.76 months. DU recurrence occurred in two patients, after a mean period of two months. The number of DU decreased from 2.23±2.20 at baseline, to 0.84±0.80 at one month (p value= 0.04), and 0.50±0.67 at 3 months (p value= 0.015). DUCAS score dropped from 6.84±1.62 before the treatment, to 1.76±2.00 and 1.16±2.55 at one and three months, respectively (p value <0.0001). No serious adverse events were observed.

Conclusion

G- CSF treatment was found to be beneficial for refractory SSc DU, resulting in DU healing and sustained remission in most cases. No significant side effects were observed. Future trials are needed to evaluate the efficacy and safety of this therapy.

References

[1]Denton CP, Khanna D. Systemic sclerosis. Lancet. 2017;390(10103):1685-1699.

[2]Mouthon L, Mestre-Stanislas C, Bérezné A, et al. Impact of digital ulcers on disability and health-related quality of life in systemic sclerosis. Annals of the Rheumatic diseases 2010; 69:214-217.

[3]Hughes M, Pauling JD. Exploring the patient experience of digital ulcers in systemic sclerosis. Semin Arthritis Rheum. 2019;48(5):888-894.

[4]Matucci-Cerinic M, Krieg T, Guillevin L, et al. Elucidating the burden of recurrent and chronic digital ulcers in systemic sclerosis: long-term results from the DUO Registry. Ann Rheum Dis. 2016;75(10):1770-1776.

[5] Steen V, Denton CP, Pope JE, Matucci-Cerinic M. Digital ulcers: overt vascular disease in systemic sclerosis. Rheumatology (Oxford). 2009;48 Suppl 3:iii19-24.

[6]Roberts AW. G-CSF: a key regulator of neutrophil production, but that's not all! Growth Factors. 2005;23(1):33-41.

[7]Phillipson M, Kubes P. The Healing Power of Neutrophils. Trends Immunol. 2019;40(7):635-647.

[8]Giuggioli D, Magistro R, Colaci M, Franciosi U, Caruso A, Ferri C. The treatment of skin ulcers in systemic sclerosis: use of granulocyte-colony stimulating factor (G-CSF) in 26 patients. Reumatismo. 2006;58(1):26-30.

Table 1.

Patients’ characteristics:

ParameterSSc IDUMean age at DU onset (years) ±SD53.5 ± 11.1Female gender (N, %)9, 90%AntibodiesATA (N, %)3, 30%ACA (N, %)5, 50%Negative2, 20%Diffuse SSc subtype (N, %)5, 50%Treatment (N, %)bosentan10, 100%sildenafil6, 60%CCB2, 20%iloprost10, 100%Mean Number of DU- baseline2.23 ± 2.20Mean Number of DU – 1 month ±SD0.84 ± 0.80Mean Number of DU – 3 months ±SD0.50 ± 0.67Mean DU duration before G-CSF (months)±SD4.77 ± 4.53Mean time to heal- (months)±SD1.57 ± 0.75Mean DUCAS before ±SD6.84 ± 1.62Mean change in DUCAS- 1M ±SD5.07 ± 2.75Mean change in DUCAS- 3M ±SD5.58 ± 2.53Adverse reactions (N, %)0, 0%

Abrreviations: SD- standard deviation, DU- digital ulcers, SSc- systemic sclerosis, ATA- anti topoisomerase antibodies, ACA- anti centromere antibodies, CCB- calcium channel blockers, G- CSF- Granulocyte-colony stimulating factor, DUCAS- digital ulcer clinical assessment score.

Disclosure of Interests

None declared

Molecular characterization of Dipetalonema yatesi from the black-faced spider monkey (Ateles chamek) with phylogenetic inference of relationships among Dipetalonema of Neotropical primates

Species of the genus Dipetalonema are parasitic nematodes of the family Onchocercidae (Nematoda; Filarioidea) which infect the peritoneal cavity of Neotropical primates. Of these, six species have been taxonomically described, two of these have been reported infecting the black-faced spider monkey (Ateles chamek): Dipetalonema gracile and Dipetalonema yatesi. Description of Dipetalonema species have been based on morphological characteristics, and their phylogenetic relationships remain unresolved. A few molecular studies have been carried out in Dipetalonema spp. infecting Neotropical primates. Seven filarioid nematodes (6 females and one male) recovered from one A. chamek in the Peruvian Amazon rainforest were morphologically identified as D. yatesi and molecularly characterized. A multi-locus genetic analysis of nuclear ribosomal region (18S) and mitochondrial (cox1, 12S, and nad5) gene sequences supported D. yatesi as a distinct lineage and yielded a highly resolved phylogenetic lineage tree for this filarioid genus of Neotropical primates. Our results highlighted that Dipetalonema species are divided in two well-supported clades, one containing D. yatesi and D. caudispina, and the second containing D. robini, D. gracile, and D. graciliformis. Due to sequence ambiguities from GenBank entries, relationships among isolates of D. gracile and D. graciliformis cannot be fully resolved, which requires further investigation. However, this suggests that these could represent a species complex. Our study confirms that D. yatesi is a valid species and constitutes the first molecular phylogenetic analysis of this parasite in black-faced spider monkeys.

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Dipetalonema yatesi from the black-faced spider monkey (Ateles chamek) in Peru.

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Characterization of D. yatesi nuclear ribosomal and mitochondrial gene sequences.

•

Phylogenetic inference of relationships among Dipetalonema species.

•

Dipetalonema yatesi and D. caudispina form a well-supported clade.

•

Relationships among D. gracile and D. graciliformis isolates are not fully resolved.

One map: Using geospatial analysis to understand lead exposure across humans, animals, and the environment in an urban US city

Environmental lead contamination negatively impacts human, animal, and ecosystem health, yet there is a lack of research in this area that incorporates a One Health framework - examining co-exposures among species through their shared environment. The purpose of this study was to integrate human and animal data with public soil lead levels to better understand lead exposure patterns across species in an urban US city. Over 200 soil samples were collected, analyzed for lead, and mapped in combination with other risk factors pulled from the literature to identify areas of highest risk. Human socio-demographic data, dog, and house sparrow density data were mapped to investigate the association between these variables and soil lead levels. Geospatial analysis software was used to visualize the geospatial distribution of soil lead levels and known risk factors for environmental lead contamination, and a block group risk score was calculated and mapped. Associations between human and animal-associated variables and soil lead levels and block risk scores were assessed using Spearman's correlations. Positive, statistically significant associations were found between soil lead levels and higher population density, higher education levels, and higher median household income. Areas with higher soil lead levels and lead exposure risk scores were associated with greater dog density and greater house sparrow density. This study fills an important knowledge gap on the risk of environmental lead exposure to humans, domestic animals, and wildlife.

Challenges to IUCN Guideline Implementation in the Rehabilitation and Release of Trafficked Primates in Peru

The rehabilitation and release of nonhuman primates after confiscation, surrender, or abandonment during illegal wildlife trafficking has implications for conservation, animal welfare, and public health. Risks associated with primate release include ecosystem disruption, inability of released primates to engage in normal foraging and social behaviors, and pathogen spillover. The International Union for the Conservation of Nature (IUCN) has several guidelines for the rehabilitation and release of trafficked primates intended to minimize such risks, though little is known about the use of these guidelines during primate confiscation, rehabilitation, and release or about the challenges faced by those who attempt to implement such guidelines in specific contexts. As one of the leading sources of Neotropical primate trade in the world, Peru has a primate population particularly vulnerable to the negative consequences of trafficked primate release. This study used semi-structured interviews and structured questionnaires of 19 people involved in primate confiscation, rehabilitation, and/or release in Peru and found that awareness and implementation of the IUCN guidelines are minimal. Opportunities to increase guideline implementation in Peru include expanding government involvement and support, adapting guidelines to specific contexts and locations, and establishing a platform for increased communication, cooperation, and research amongst those performing this work.

Perceptions of Maternal Discrimination and Pregnancy/Postpartum Experiences Among Veterinary Mothers

Objective: To describe perceptions of maternal discrimination and to begin to understand patterns around timing of starting families, infertility, and post-partum depression among veterinary mothers. Design: Cross-sectional questionnaire with closed and open-ended questions posted to a social media platform "Moms with a DVM." Sample: 1,082 veterinary mothers in the United States. Procedures: An online questionnaire was administered regarding perceived discrimination, inequities in the work-place due to pregnant or maternal status, desired accommodations, timing of pregnancy(ies), fertility issues, and postpartum experiences. Results: At least one form of perceived discrimination was reported by 819 (75.7%) respondents (M = 2.6, SD = 2.1, range 0-10). Specifically, 789 (72.9%) reported maternal discrimination. Over half of the sample (n = 632, 58.4%) reported at least one instance of perceived inequity in the workplace due to status as a mother (M = 1.23, SD = 1.4, range 0-5). A majority (906, 83.7%) reported that their career had "definitely" or "maybe" affected the timing of their children. One hundred eighty-nine respondents (17.5%) experienced at least one miscarriage, and 192 (17.6%) used fertility treatment due to difficulty conceiving. Postpartum depression was diagnosed in 181 respondents (16.7%), and 353 (32.6%) reported symptoms consistent with postpartum depression but did not seek medical care. Of 953 participants who needed accommodations for breastfeeding and/or pumping while at work, 130 (13.6%) reported excellent accommodations, 454 (47.6%) adequate, 258 (27.1%) inadequate, and 111 (11.6%) had no accommodations provided. Conclusions and Clinical Relevance: Participants reported experiences of perceived maternal discrimination, as well as inequities and lack of support services due to status as a mother. These results highlight the need for attention and changes to ensure veterinarians have supportive and sustainable career options.

Optimizing a Noninvasive Oral Sampling Technique for Semicaptive Neotropical Primates in Peru

Disease surveillance in Neotropical primates (NP) is limited by the difficulties associated with anesthetizing NP for sample collection in remote settings. Our objective was to optimize a noninvasive method of oral sampling from semicaptive NP in Peru. We offered 40 NP at Taricaya Rescue Centre in Madre de Dios, Peru ropes coated in various attractants and measured variables (acceptance of the rope, chewing time, and volume of fluid eluted from ropes) that may affect sample acquisition and quality. We preserved samples by direct freezing in liquid nitrogen or by storing samples in RNA stabilization reagent at room temperature. Sample integrity was measured by testing for mammalian cytochrome b with the use of conventional PCR. The NP successfully chewed on a rope in 82% (125/152) of trials. Overall sample integrity was high, with 96% (44/46) of samples (both directly frozen and stored in stabilization reagent) testing positive for cytochrome b. The number of times that an individual NP was exposed to the rope procedure and NP age were associated with higher acceptance rates and the NP successfully chewing on the rope. We conclude that ropes serve as a feasible noninvasive method of obtaining oral samples from NP at rescue centers and could be used in future studies to evaluate population genetics and for pathogen surveillance for population health monitoring.

Subgingival Microbiota and Longitudinal Glucose Change: The Oral Infections, Glucose Intolerance and Insulin Resistance Study (ORIGINS)

Microbial communities along mucosal surfaces throughout the digestive tract are hypothesized as risk factors for impaired glucose regulation and the development of clinical cardiometabolic disease. We investigated whether baseline measures of subgingival microbiota predicted fasting plasma glucose (FPG) longitudinally. The Oral Infections, Glucose Intolerance and Insulin Resistance Study (ORIGINS) enrolled 230 diabetes-free adults (77% female) aged 20 to 55 y (mean ± SD, 34 ± 10 y) from whom baseline subgingival plaque and longitudinal FPG were measured. DNA was extracted from subgingival plaque, and V3 to V4 regions of the 16S rRNA gene were sequenced. FPG was measured at baseline and again at 2 y; glucose change was defined as follow-up minus baseline. Multivariable linear models regressed 2-y glucose change onto baseline measures of community diversity and abundances of 369 individual taxa. A microbial dysbiosis index (MDI) summarizing top individual taxa associated with glucose change was calculated and used in regression models. Models were adjusted for age, sex, race/ethnicity, education, smoking status, body mass index, and baseline glucose levels. Statistical significance was based on the false discovery rate (FDR; <0.05) or a Bonferroni-corrected P value of 1 × 10^-4, derived from the initial 369 hypothesis tests for specific taxa. Mean 2-y FPG change was 1.5 ± 8 mg/dL. Baseline levels of 9 taxa predicted FPG change (all FDR <0.05), among which Stomatobaculum sp oral taxon 097 and Atopobium spp predicted greater FPG change, while Leptotrichia sp oral taxon 498 predicted lesser FPG change (all 3 P values, Bonferroni significant). The MDI explained 6% of variation in longitudinal glucose change (P < 0.001), and baseline glucose levels explained 10% of variation (P < 0.0001). FPG change values ± SE in the third versus first tertile of the MDI were 4.5 ± 0.9 versus 1.6 ± 0.9 (P < 1 × 10^-4). Subgingival microbiota predict 2-y glucose change among diabetes-free men and women.

Knowledge, attitudes and practices related to schistosomiasis transmission and control in Leyte, Philippines

Schistosomiasis is a chronic but preventable disease that affects 260 million people worldwide. In the Philippines, 860,000 people are afflicted with Schistosoma japonicum annually, and another 6.7 million live in endemic areas. The disease’s complex epidemiology as well as the influence of poverty in endemic areas demand an integrated, multi-sectoral approach to disease control. Results from behavioral or sociocultural studies on schistosomiasis could improve the content and impact of schistosomiasis control in rural villages in the Philippines. We investigated knowledge, attitudes and practices related to schistosomiasis transmission and control in an endemic village in Leyte Province, Philippines. We administered a questionnaire to 219 participants covering 1) knowledge and attitudes related to schistosomiasis, its symptoms, and its transmission; 2) attitudes and practices in relation to schistosomiasis prevention; 3) willingness to comply with public health control programs; and 4) whether the respondent had previously contracted schistosomiasis. Responses revealed fairly high measures of schistosomiasis knowledge (mean 17.0 out of 23 questions, range 6–23), but also inconsistent disease prevention behavior. A high proportion of participants (72.6%, n = 159) reported previous disease. Participant belief in the preventability of schistosomiasis was revealed to be a key attitude, as carabao owners who believed in prevention were over five times more likely to be willing to vaccinate their carabaos (OR = 5.24, 95% CI 1.20–27.68, P = 0.04). Additionally, participants who did not believe in prevention were about twice as likely to report previous disease (OR = 2.31, 95% CI 1.02–5.63, P = 0.05). Our results suggest that future public health interventions should address barriers to disease-preventing behavior, as well as maintaining community belief in disease prevention. Comprehensive disease control programs should be supplemented by sociocultural and behavioral context in order to improve their impact in endemic communities.

Schistosomiasis is a chronic tropical disease caused by parasitic worms of the genus Schistosoma. In the Philippines, Schistosoma japonicum afflicts over 800,000 people annually, and another 6.7 million live in endemic areas. The current national control program based on human mass treatment has been unable to eliminate schistosomiasis on its own. This is in part due to the poverty of endemic areas as well as the parasite’s complex life cycle, which includes transmission by freshwater snails and livestock. A more comprehensive disease control strategy would include periodic treatment and vaccination of the widely used domestic water buffalo or carabao. Sociocultural and behavioral research would also inform and improve the impact of future control programs. To this end, we investigated knowledge, attitudes, and practices related to schistosomiasis in an endemic village in Leyte, Philippines. We found high levels of disease knowledge and awareness, but also inconsistencies in disease prevention habits. Belief in whether schistosomiasis could be prevented was important in this community, associated with previous disease experience as well as receptivity to new strategies like livestock vaccination. This kind of social context is vital to future public health campaigns, and highlights the importance of cross-disciplinary work to achieve successful disease control.

Demographics and anthropometrics impact benefits of health intervention: data from the Reduce Obesity and Diabetes Project

OBJECTIVE

To determine the efficacy of a 4-month school-based health, nutrition and exercise intervention on body fatness and examine possible effects of demographic and anthropometric covariates.

METHODS

Height, weight, waist circumference and body composition were measured in a diverse population of 644 NYC middle school students (mean ± SD age 12.7 ± 0.9 years; 46% male; 38% Hispanic, 17% East Asian, 15% South Asian, 13.5% African American, 8.5% Caucasian, 8% other) during the fall and spring semesters. Year 1 participants (n = 322) were controls. Experimental participants (year 2, n = 469) received a 12-session classroom-based health and nutrition educational programme with an optional exercise intervention.

RESULTS

Groups were demographically and anthropometrically similar. The intervention resulted in significant reductions in indices of adiposity (ΔBMI z-scores [-0.035 ± 0.014; p = 0.01], Δ% body fat [-0.5 ± 0.2; p < 0.0001] and Δwaist circumference [-0.73 ± 0.30 cm; p < 0.0001]). Intervention effects were greater (p = 0.01) in men (ΔBMI z-score = -0.052 ± 0.015) versus women (0.022 ± 0.018), participants who were obese (ΔBMI z-score -0.083 ± 0.022 kg m-2) versus lean (-0.0097 ± 0.020 kg m-2) and South Asians (Δ% body fat -1.03 ± 0.35) versus total (-0.49 ± 0.20%) participants (p = 0.005).

CONCLUSION

A 4-month school-based health intervention was effective in decreasing measures of adiposity in middle school students, particularly in men, participants who were obese and South Asians.

Lead exposure to children from consumption of backyard chicken eggs

Backyard chicken ownership is rapidly increasing in urban areas in the United States, largely as a way to provide eggs for household consumption. Despite elevated levels of environmental lead contamination in many US cities, the role of backyard chicken eggs as a pathway for lead exposure, particularly for children, has received limited scrutiny. To characterize lead exposure from consumption of backyard chicken eggs for children and predict related effects on blood lead level (BLL), we conducted a cross-sectional study of backyard chicken owners in the Greater Boston area (n = 51). We interviewed participants regarding egg consumption by household members and collected backyard eggs (n = 201) and coop soil samples (n = 48) for analysis. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate lead concentration in homogenized eggs and an X-ray fluorescence (XRF) portable device was used to assess soil lead levels in the laboratory. We used the USEPA's Integrated Exposure Uptake Biokinetic Model for Lead in Children (IEUBK) to assess the relative contribution of backyard egg consumption to aggregate BLL in children. Four scenarios were developed in the IEUBK model to address variability in egg consumption rates and egg lead contamination. Lead was detected in egg samples from 98% of the households that provided egg samples. Mean household lead concentration was 0.10 μg/g (SD: 0.18). Egg lead concentrations ranged from below the limit of detection (0.0014 μg/g) to 1.798 μg/g (<1.4-1198 ppb). Egg lead levels were strongly positively correlated with lead concentration in coop soil (r = 0.64; p < 0.001). In modeled scenarios where a child < 7 years frequently ate eggs highly contaminated with lead, BLLs are predicted to increase by 0.9-1.5 μg/dL. In three other scenarios reflecting more moderate egg lead contamination and consumption rates, BLLs were predicted to increase from 0.1 to 0.8 μg/dL. Consumption of backyard chicken eggs can contribute to lead exposure in children. Soil lead remediation prior to chicken ownership may reduce lead exposure from backyard eggs.

Pathways and mechanisms linking dietary components to cardiometabolic disease: thinking beyond calories

Calories from any food have the potential to increase risk for obesity and cardiometabolic disease because all calories can directly contribute to positive energy balance and fat gain. However, various dietary components or patterns may promote obesity and cardiometabolic disease by additional mechanisms that are not mediated solely by caloric content. Researchers explored this topic at the 2017 CrossFit Foundation Academic Conference 'Diet and Cardiometabolic Health - Beyond Calories', and this paper summarizes the presentations and follow-up discussions. Regarding the health effects of dietary fat, sugar and non-nutritive sweeteners, it is concluded that food-specific saturated fatty acids and sugar-sweetened beverages promote cardiometabolic diseases by mechanisms that are additional to their contribution of calories to positive energy balance and that aspartame does not promote weight gain. The challenges involved in conducting and interpreting clinical nutritional research, which preclude more extensive conclusions, are detailed. Emerging research is presented exploring the possibility that responses to certain dietary components/patterns are influenced by the metabolic status, developmental period or genotype of the individual; by the responsiveness of brain regions associated with reward to food cues; or by the microbiome. More research regarding these potential 'beyond calories' mechanisms may lead to new strategies for attenuating the obesity crisis.

Self-reported Animal and Ectoparasite Exposure among Urban Homeless People

Homeless people in the United States may experience poor hygiene and spend extended periods of time outdoors, which increases exposure to animal and insect vectors of disease. Despite these risks, efforts to understand frequency and risk factors for zoonotic and vector-borne infections among homeless people have been limited. We queried homeless people in Boston, Massachusetts (n=194) to evaluate exposure to urban wildlife and ectoparasites associated with infection. Thirty percent of participants reported seeing rodents daily, and 25% reported daily sightings of cats. Body lice and fleas were reported by 4% and 11% of participants, respectively. Sleeping outdoors and heavy drinking were positively associated with rodent and ectoparasite exposure. Frequent sightings of rodents and rodent feces among homeless people in particular areas may indicate human exposure risk to urban rodent-borne pathogens, including Leptospira spp, Seoul hantavirus, and Rickettsia akari. Epidemiologic studies of zoonotic and vector-borne infections in this population are warranted.

Periodontal Bacteria and Prediabetes Prevalence in ORIGINS: The Oral Infections, Glucose Intolerance, and Insulin Resistance Study

Periodontitis and type 2 diabetes mellitus are known to be associated. The relationship between periodontal microbiota and early diabetes risk has not been studied. We investigated the association between periodontal bacteria and prediabetes prevalence among diabetes-free adults. ORIGINS (the Oral Infections, Glucose Intolerance and Insulin Resistance Study) cross sectionally enrolled 300 diabetes-free adults aged 20 to 55 y (mean ± SD, 34 ± 10 y; 77% female). Prediabetes was defined as follows: 1) hemoglobin A1c values ranging from 5.7% to 6.4% or 2) fasting plasma glucose ranging from 100 to 125 mg/dL. In 1,188 subgingival plaque samples, 11 bacterial species were assessed at baseline, including Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Actinomyces naeslundii. Full-mouth clinical periodontal examinations were performed, and participants were defined as having no/mild periodontitis vs. moderate/severe periodontitis per the definition of the Centers for Disease Control and Prevention / American Academy of Periodontology. Modified Poisson regression evaluated prediabetes prevalence across bacterial tertiles. Prevalence ratios and 95% confidence intervals for third vs. first tertiles are presented. All analyses were adjusted for cardiometabolic risk factors. All results presented currently arise from the baseline cross section. Prediabetes prevalence was 18%, and 58% of participants had moderate/severe periodontitis. Prevalence ratios (95% confidence intervals) summarizing associations between bacterial levels and prediabetes were as follows: A. actinomycetemcomitans, 2.48 (1.34, 4.58), P = 0.004; P. gingivalis, 3.41 (1.78, 6.58), P = 0.0003; T. denticola, 1.99 (0.992, 4.00), P = 0.052; T. forsythia, 1.95 (1.0, 3.84), P = 0.05; A. naeslundii, 0.46 (0.25, 0.85), P = 0.01. The prevalence ratio for prediabetes among participants with moderate/severe vs. no/mild periodontitis was 1.47 (0.78, 2.74), P = 0.23. Higher colonization levels of specific periodontal microbiota are associated with higher prediabetes prevalence among diabetes-free adults.

Detection of Mycobacterium tuberculosis Complex in New World Monkeys in Peru

The Mycobacterium tuberculosis complex causes tuberculosis in humans and nonhuman primates and is a global public health concern. Standard diagnostics rely upon host immune responses to detect infection in nonhuman primates and lack sensitivity and specificity across the spectrum of mycobacterial infection in these species. We have previously shown that the Oral Swab PCR (OSP) assay, a direct pathogen detection method, can identify the presence of M. tuberculosis complex in laboratory and free-ranging Old World monkeys. Addressing the current limitations in tuberculosis diagnostics in primates, including sample acquisition and pathogen detection, this paper furthers our understanding of the presence of the tuberculosis-causing bacteria among New World monkeys in close contact with humans. Here we use the minimally invasive OSP assay, which includes buccal swab collection followed by amplification of the IS6110 repetitive nucleic acid sequence specific to M. tuberculosis complex subspecies, to detect the bacteria in the mouths of Peruvian New World monkeys. A total of 220 buccal swabs from 16 species were obtained and positive amplification of the IS6110 sequence was observed in 30 (13.6%) of the samples. To our knowledge, this is the first documentation of M. tuberculosis complex DNA in a diverse sample of Peruvian Neotropical primates.

Plasma advanced glycation end products (AGEs), receptors for AGEs and their correlation with inflammatory markers in middle school-age children

AIM

Advanced glycation end products (AGEs) and/or their receptors (RAGE) are significantly positively correlated with adiposity, inflammation, dyslipidemia, and insulin resistance in adults. However, the relationships between AGEs, RAGE, and adiposity-related comorbidites in children have not been well studied.

METHODS

In a cross-sectional study of 88 children (age 11-15 years) from the New York area enrolled in the Reduce Obesity and Diabetes (ROAD) study, we examined the correlation of the AGE N(ε)-(carboxymethyl)lysine (CML), soluble RAGE (sRAGE), and endogenous secretory RAGE (esRAGE) with adiposity, inflammatory markers [interleukin-6 (IL-6), C-reactive protein, tumor necrosis factor-α], adiponectin, lipids, insulin sensitivity, and insulin secretory capacity.

RESULTS

Pediatric CML levels were ~20% below average adult levels. CML was significantly (p < 0.05) positively correlated with age and insulin sensitivity and negatively with adiposity, dyslipidemia and IL-6. sRAGE correlated positively with esRAGE and negatively with adiposity and IL-6. Both sRAGE and esRAGE correlated negatively with insulin secretory capacity.

CONCLUSION

Our findings suggest that unlike adults, CML is negatively associated with adiposity and adiposity-related comorbidity risk in children. As in adults, sRAGE and esRAGE were, to varying degrees, negatively correlated with body fatness and risk factors for adiposity-related comorbidities.

Campylobacter antimicrobial resistance in Peru: a ten-year observational study

Background

Campylobacter jejuni and Campylobacter coli are food-borne pathogens of great importance and feature prominently in the etiology of developing world enteritis and travellers’ diarrhoea. Increasing antimicrobial resistant Campylobacter prevalence has been described globally, yet data from Peru is limited. Our objective was to describe the prevalence trends of fluoroquinolone and macrolide-resistant C. jejuni and C. coli stool isolates from three regions in Peru over a ten-year period.

Methods

Surveillance for enteric pathogens was conducted in Lima, Iquitos and Cusco between 2001 and 2010. Campylobacter stool isolates were tested for susceptibilities to ciprofloxacin, azithromycin and erythromycin. Susceptibilities were reviewed for 4652 isolates from Lima ( n = 3419), Iquitos ( n = 625) and Cusco ( n = 608).

Results

Comparing the study periods of 2001-2005 and 2006-2010, prevalence of ciprofloxacin-resistant C. jejuni isolates rose in the study areas of Lima (73.1% to 89.8%, p < 0.001) and Iquitos (24.1% to 48.9%, p < 0.001). Ciprofloxacin-resistant C. coli rates also increased in Lima (48.1% to 87.4%, p < 0.001) and Cusco (10.0% to 65.9%, p = 0.005). Small but significant increases in azithromycin-resistant and erythromycin-resistant C. jejuni prevalence were noted in Iquitos (2.2% to 14.9%, p < 0.001; 3.2% to 14.9%, p = 0.002), and erythromycin-resistant C. coli rates increased in Lima (0.0% to 5.3%, p = 0.038). The prevalence of C. jejuni isolates resistant to both ciprofloxacin and azithromycin increased in Iquitos (0.3% to 14.9%, p < 0.001) and Lima (0.3% to 1.6%, p = 0.011), and prevalence of C. jejuni isolates resistant to both ciprofloxacin and erythromycin rose in Iquitos (0.0% to 14.9%, p < 0.001). Ciprofloxacin and erythromycin resistant C. coli prevalence increased in Lima (0.0% to 5.3%, p = 0.034).

Conclusions

These results have implications for the empirical management of enterocolitis in Peru. Ongoing surveillance is essential to guide appropriate antimicrobial use in this setting. Local epidemiological studies to explore the relationship between increasing antimicrobial resistance and agricultural or human antibiotic use may be valuable.

Effects of chronic weight perturbation on energy homeostasis and brain structure in mice

Maintenance of reduced body weight in lean and obese human subjects results in the persistent decrease in energy expenditure below what can be accounted for by changes in body mass and composition. Genetic and developmental factors may determine a central nervous system (CNS)-mediated minimum threshold of somatic energy stores below which behavioral and metabolic compensations for weight loss are invoked. A critical question is whether this threshold can be altered by environmental influences and by what mechanisms such alterations might be achieved. We examined the bioenergetic, behavioral, and CNS structural responses to weight reduction of diet-induced obese (DIO) and never-obese (CON) C57BL/6J male mice. We found that weight-reduced (WR) DIO-WR and CON-WR animals showed reductions in energy expenditure, adjusted for body mass and composition, comparable (-10-15%) to those seen in human subjects. The proportion of excitatory synapses on arcuate nucleus proopiomelanocortin neurons was decreased by ∼50% in both DIO-WR and CON-WR mice. These data suggest that prolonged maintenance of an elevated body weight (fat) alters energy homeostatic systems to defend a higher level of body fat. The synaptic changes could provide a neural substrate for the disproportionate decline in energy expenditure in weight-reduced individuals. This response to chronic weight elevation may also occur in humans. The mouse model described here could help to identify the molecular/cellular mechanisms underlying both the defense mechanisms against sustained weight loss and the upward resetting of those mechanisms following sustained weight gain.

Adaptive thermogenesis in humans

The increasing prevalence of obesity and its comorbidities reflects the interaction of genes that favor the storage of excess energy as fat with an environment that provides ad libitum availability of energy-dense foods and encourages an increasingly sedentary lifestyle. Although weight reduction is difficult in and of itself, anyone who has ever lost weight will confirm that it is much harder to keep the weight off once it has been lost. The over 80% recidivism rate to preweight loss levels of body fatness after otherwise successful weight loss is due to the coordinate actions of metabolic, behavioral, neuroendocrine and autonomic responses designed to maintain body energy stores (fat) at a central nervous system-defined 'ideal'. This 'adaptive thermogenesis' creates the ideal situation for weight regain and is operant in both lean and obese individuals attempting to sustain reduced body weights. Much of this opposition to sustained weight loss is mediated by the adipocyte-derived hormone 'leptin'. The multiple systems regulating energy stores and opposing the maintenance of a reduced body weight illustrate that body energy stores in general and obesity in particular are actively 'defended' by interlocking bioenergetic and neurobiological physiologies. Important inferences can be drawn for therapeutic strategies by recognizing obesity as a disease in which the human body actively opposes the 'cure' over long periods of time beyond the initial resolution of symptomatology.

The effect of osmotic stress on the cell volume, metaphase II spindle and developmental potential of in vitro matured porcine oocytes

Porcine animal models are used to advance our understanding of human physiology. Current research is also directed at methods to produce transgenic pigs. Cryobanking gametes and embryos can facilitate the preservation of valuable genotypes, yet cryopreserving oocytes from pigs has proven very challenging. The current study was designed to understand the effects of anisotonic solutions on in vitro matured porcine oocytes as a first step toward designing improved cryopreservation procedures. We hypothesized that the proportion of oocytes demonstrating a normal spindle apparatus and in vitro developmental potential would be proportional to the solution osmolality. Oocytes were incubated for 10 min at 38 degrees C in various hypo- or hypertonic solutions, and an isotonic control solution and then assessed for these two parameters. Our results support the hypothesis, with an increasing proportion of spindles showing a disrupted structure as the levels of anisotonic exposure diverge from isotonic. Only about half of the oocytes maintained developmental potential after exposure to anisotonic solutions compared to untreated controls. Oocyte volume displayed a linear response to anisotonic solutions as expected, with an estimated relative osmotically inactive cell volume of 0.178. The results from this study provide initial biophysical data to characterize porcine oocytes. The results from future experiments designed to determine the membrane permeability to various cryoprotectants will allow predictive modeling of optimal cryopreservation parameters and provide a basis for designing improved cryopreservation procedures.

Metabolic and hemodynamic responses to exercise in subcutaneous adipose tissue and skeletal muscle

This study evaluated the effect of standardized bicycle exercise on metabolism and blood flow in abdominal ( aSAT) and femoral subcutaneous adipose tissue ( fSAT) and skeletal muscle in eleven women and nine men. Using microdialysis, the respective tissues were perfused with Ringer's solution (+ 50 mM ethanol) and dialysate [ethanol], [glycerol], [lactate] and [pyruvate] were measured in order to estimate blood flow (ethanol dilution technique), lipolysis and glycolysis, respectively. At rest, blood flow tended to be higher in the respective tissues of women when compared to men. During exercise, blood flow was increased significantly in fSAT and muscle, but not in aSAT. Dialysate [glycerol] was increased two- to three-fold in aSAT and fSAT, similarly in men and women. However, in muscle, dialysate [glycerol] was increased five-fold in women and four-fold in men without reaching a steady state in women. Corrected for blood flow, the increase in lipolysis was greater in muscle than in fSAT, and greater in fSAT than in aSAT, and in muscle the increase was greater for women compared with men. Dialysate [lactate] and [lactate]/[pyruvate] ratio were much more increased in muscle compared with aSAT and fSAT. It is concluded that lipids stored in muscle are rather used than lipids stored in adipose tissue for fueling the energy metabolism of muscle during exercise. During exercise, lipid mobilization is much greater in women than in men.

Sexual dimorphism in the energy content of weight change

BACKGROUND

The energy content of weight change is assumed to be sex- and age-neutral at 3,500 kcal/pound or 32.2 MJ/kg.

OBJECTIVES

As sexual dimorphism in body composition generally exists in mammals, the primary hypothesis advanced and tested was that the energy content of weight change differs between men and women.

DESIGN

The energy content of 129 adult men and 287 women was measured by neutron activation analysis. Cross-sectional energy content prediction models were developed and then evaluated in two longitudinal samples: one that used the same methods in 26 obese women losing weight; and the other a compilation of 18 previously reported weight change-body composition studies.

RESULTS

Multiple regression modeling identified weight, sex, age and height as total energy content predictor variables with significant sex x weight (P<0.001) and age x weight (P<0.001) interactions; total model r(2) and s.e.e. were 0.89 and 107.3 MJ, respectively. The model's predictive value was supported in both longitudinal evaluation samples. Model calculations using characteristics of representative adults gaining or losing weight suggested that the energy content of weight change in women (approximately 30.1-32.2 MJ/kg) is near to the classical value of 32.2 MJ/kg and that in men the value is substantially lower, approximately 21.8-23.8 MJ/kg. The predicted energy content of weight change increases by about 10% in older (age approximately 70 y) vs younger (approximately 35 y) men and women.

CONCLUSIONS

Sexual dimorphism and age-dependency appears to exist in the estimated energy content of weight change and these observations have important clinical and research implications.

Sexual dimorphism in circulating leptin concentrations is not accounted for by differences in adipose tissue distribution

BACKGROUND

Circulating concentrations of leptin normalized to total adipose tissue mass are significantly greater in females than in males. Rates of leptin expression (per gram of adipose tissue) are significantly greater in subcutaneous (SAT) than visceral (VAT) adipose tissue and the relative amount of fat stored as SAT vs VAT is significantly greater in pre-menopausal females than in males. Gender-related differences in the relative amounts of SAT and VAT may account for the greater circulating leptin concentration relative to fat-mass in females than males.

METHODS

We examined body composition and anatomic fat distribution by dual energy X-ray-absorptiometry (DEXA) and magnetic resonance imaging (MRI), and post-absorptive circulating concentrations of leptin and insulin in 58 subjects (26 females, 32 males). Stepwise multiple linear regression analyses, treating gender as a dichotomous variable, were performed to determine inter-relationships among leptin concentrations and insulin concentrations, VAT and SAT.

RESULTS

Body composition by DEXA and MRI were highly correlated (r(2)=0.97, P<0.0001). There were significant gender effects on leptin/total fat mass (males, 0.17+/-0.01 ng/ml/kg; females, 0.49+/-0.05 ng/ml/kg; P<0.0001) and relative amounts of fat in SAT and VAT depots (ratio of SAT/VAT; males, 12.3+/-1.5; females, 32.9+/-3.2; P<0.0001). Circulating leptin concentration was significantly correlated with insulin concentration (P=0.001), SAT (P<0.0001) and gender (P=0.033). Circulating concentrations of insulin were significantly correlated with VAT, but not SAT, in males and with SAT, but not VAT, in females.

CONCLUSIONS

The sexual dimorphism in the relationship between leptin and adipose tissue mass cannot be explained by differences in the relative amounts of VAT and SAT. Thus, the sexual dimorphism in plasma leptin concentration appears to reflect, at least in part, effects of circulating concentrations of gonadal steroids (especially androgens) and/or primary genetic differences that are independent of amounts of VAT or SAT.

Effect of puberty on the relationship between circulating leptin and body composition

Circulating concentrations of leptin are better correlated with absolute amounts of adipose tissue [fat mass (FM)] than with relative body fatness (body mass index or percent body fat). There is a clear sexual dimorphism in circulating concentrations of leptin (females > males) at birth and in adulthood. However, whether such dimorphism is present in the interval between these periods of development remains controversial. We examined body composition and clinical (Tanner stage) and endocrine (pituitary-gonadal axis hormones) aspects of sexual maturation in relationship to circulating concentrations of leptin in 102 children (53 males and 49 females, 6-19 yr of age) to evaluate the relationship between circulating leptin concentrations and body composition before and during puberty. Pubertal stage was assigned by physical examination (Tanner staging) and also assessed by measurement of plasma estradiol, testosterone, and pituitary gonadotropins. Body composition was determined by dual-energy x-ray absorptiometry and by anthropometry. Circulating concentrations of leptin in the postabsorptive state were determined by a solid-phase sandwich enzyme immunoassay. The effect of gender on the relationship between circulating leptin concentrations and FM was determined by ANOVA at each Tanner stage. Stepwise multiple linear regression analyses, including circulating concentrations of pituitary-gonadal axis hormones, and FM were performed, by gender, to determine whether the relationship between circulating concentrations of leptin and FM changes during puberty. Plasma leptin concentrations were significantly correlated with FM at all Tanner stages in males and females. Plasma leptin concentrations, normalized to FM, were significantly higher in females than males at Tanner stages IV and V but not at earlier stages of pubertal development. Plasma leptin concentrations, normalized to FM, were significantly greater in females at Tanner stage V compared with females at Tanner stage I and significantly lower in males at Tanner stage IV and V compared with males at Tanner stage I. These significant gender and maturational differences were confirmed by demonstrating that the regression equation relating circulating leptin concentrations to FM in females and males at Tanner stages IV and V were significantly different (predicted lower leptin concentrations in males than females with identical body composition) and that the regression equations relating circulating concentrations of leptin to FM in each gender before puberty (Tanner stage I) were significantly different (predicted higher plasma concentrations of leptin in prepubertal males and lower leptin concentrations in prepubertal females) than the same regression equations in later puberty. Circulating concentrations of testosterone were significant negative correlates of circulating concentrations of leptin normalized to FM in males when considered as a group over all pubertal stages. The inclusion in multivariate regression analyses of circulating concentrations of testosterone and estradiol, FM, fat-free mass, and gender did not eliminate a significant gender-effect (P < 0.05) on circulating concentrations of leptin at Tanner stages IV and V. The circulating concentration of leptin, normalized to FM, declines significantly in males and rises significantly in females late in puberty to produce a late-pubertal/adult sexual dimorphism. These studies confirm a potent role for gonadal steroids as mediators of this sexual dimorphism in circulating concentrations of leptin. (ABSTRACT TRUNCATED)

Effects of changes in body weight on carbohydrate metabolism, catecholamine excretion, and thyroid function

BACKGROUND

Weight gain and loss increases and decreases energy expenditure, respectively, out of proportion to changes in metabolic mass.

OBJECTIVE

We hypothesized that changes in energy expenditure associated with weight gain or loss were due in part to changes in catecholamine release, thyroid hormones, carbohydrate utilization, or a combination thereof.

METHODS

Urinary catecholamine excretion, serum thyroid hormone concentrations, and results of 3-h oral-glucose-tolerance tests were examined in obese and never-obese subjects at their usual weights, during weight loss or gain, and at stable weights 10-20% below or 10% above usual.

RESULTS

Urinary norepinephrine excretion decreased significantly during and after weight loss and increased during and after weight gain. Serum concentrations of reverse triiodothyronine increased significantly during and after weight loss, whereas serum concentrations of triiodothyronine increased significantly (by approximately 0%) during and after weight gain. Serum insulin and glucose concentrations during the oral-glucose-tolerance test increased significantly after weight gain in obese subjects. The percentage change in urinary norepinephrine excretion and in serum concentrations of triiodothyronine were significantly correlated with percentage changes in energy expenditure and with each other.

CONCLUSIONS

Changes in body weight were associated with changes in catecholamine excretion and thyroid hormones, which might-by virtue of the effects on energy expenditure-have favored a return to usual body weight. Weight gain induced more apparent insulin resistance in the obese than the never-obese subjects, suggesting a threshold effect of total body fat on this phenomenon.

Involvement of retinoblastoma family members and E2F/DP complexes in the death of neurons evoked by DNA damage

Neuronal death evoked by DNA damage requires cyclin-dependent kinase 4 (Cdk4) and 6 activity and is accompanied by elevation of cyclin D1-associated kinase activity. Because Cdk4/6 phosphorylates retinoblastoma protein (pRb) family members that then modulate the transcriptional activity of E2F/DP1 complexes, we examined the involvement of these components in DNA damage-evoked neuronal death. Camptothecin induced rapid pRb and p107 phosphorylation at a Cdk4/6 phosphorylation site followed by selective loss of Rb and p107. The CDK inhibitor flavopiridol suppressed pRb and p107 phosphorylation and loss, implicating CDK activity in these events. Moreover, the loss of pRb and p107 appeared to be mediated by caspases because it was blocked by general caspase inhibitors. The role of phosphorylation and pRb and p107 loss in the death pathway was indicated by observations that virally mediated expression of pRb mutated at sites of phosphorylation, including the Cdk4/6 site, inhibited death. Finally, expression of dominant-negative versions of DP1, known to compromise E2F transcriptional activity, protects cortical neurons from death induced by camptothecin and sympathetic neurons from death evoked by UV treatment. Taken together, these results implicate the CDK-pRb/E2F/DP pathway as a required element in the neuronal death evoked by DNA damage.

Psychogenic seizures--why women?

The only consistent finding in studies of psychogenic seizures is the approximately threefold higher incidence in women. Therefore, why women? Charcot and Freud emphasized the sexual aspects of the seizure as has the current interest in childhood sexual abuse. From case studies and review of the literature the author believes that psychogenic seizures in women express rage, fear, and helplessness against the dominant and abusive male rather than sexual conflicts. Emphasizing the aggressive component of seizures does not minimize the traumatic effects of sexual abuse but rather includes it as leading to rage and helplessness.

Catheter ablation of atrioventricular junction via retrograde route in a patient with single ventricle

Radiofrequency catheter ablation of the atrioventricular junction (AVJ) was performed by the retrograde route in a 19-year-old woman with atrial fibrillation and single ventricle following the bidirectional Glenn procedure. Two energy applications resulted in complete atrioventricular block and dependence on an epicardial ventricular pacemaker.

Effects of exogenous gonadal steroids on leptin homeostasis in rats

BACKGROUND

In humans, circulating concentrations of the hormone leptin, normalized to body fat mass, are significantly higher in females compared to males. This experiment was designed to determine whether the administration of exogenous androgen or estrogen would significantly alter the relationship between plasma leptin and fat mass in rats.

METHODS

In the first experiment, plasma leptin and retroperitoneal and parametrial (female)/epididymal (male) adipose tissue expression of leptin mRNA were measured in five male and five female 9.5-week-old Sprague-Dawley rats. In a second experiment, gonadectomized 10.5-week-old female Sprague-Dawley rats received 1 or 2 weeks of daily intraperitoneal injections (in oil) of 750 mg testosterone propionate, 2.5 microg of estradiol benzoate or vehicle. At 0, 1, and 2 weeks, plasma concentrations of leptin, fat pad weight of parametrial and retroperitoneal fat pads, and leptin mRNA expression by Northern blot in retroperitoneal fat pads were determined. Daily weight and food intake of animals were monitored throughout the study.

RESULTS

Circulating leptin concentrations per unit of fat pad mass and leptin mRNA expression normalized to actin mRNA were higher in gonadally intact female compared to male rats. Compared to placebo, estrogen administration decreased food intake and body weight, but had no significant effect on leptin mRNA expression or on circulating leptin concentration. Testosterone administration increased body weight and decreased expression of leptin mRNA (only after 2 weeks), but did not change food intake or circulating leptin concentration.

CONCLUSIONS

Administration of estrogen did not affect either leptin expression or the circulating concentration of leptin. Administration of androgen decreased expression of leptin mRNA. However, even after 2 weeks of testosterone administration to gonadectomized females, plasma leptin concentration, corrected for fat pad weight, was higher in gonadectomized females than in intact males. Thus, sex steroid-associated changes in plasma leptin concentration and leptin mRNA expression are not sufficient to explain the observed sexual dimorphism in plasma leptin concentrations in rats.

Genetic and physiologic analysis of the role of uncoupling protein 3 in human energy homeostasis

By virtue of its potential effects on rates of energy expenditure, uncoupling protein 3 (UCP3) is an obesity candidate gene. We identified nine sequence variants in UCP3, including Val9Met, Val102Ile, Arg282Cys, and a splice site mutation in the intron between exons 6 and 7. The splice mutation results in an inability to synthesize mRNA for the long isoform (UCP3L) of UCP3. Linkage (sib pair), association, and transmission disequilibrium testing studies on 942 African-Americans did not suggest a significant effect of UCP3 on body composition in this group. In vastus lateralis skeletal muscle of individuals homozygous for the splice mutation, no UCP3L mRNA was detectable; the short isoform (UCP3S) was present in an increased amount. In this muscle, we detected no alterations of in vitro mitochondrial coupling activity, mitochondrial respiratory enzyme activity, or systemic oxygen consumption or respiratory quotient at rest or during exercise. These genetic and physiologic data suggest the following possibilities: UCP3S has uncoupling capabilities equivalent to UCP3L; other UCPs may compensate for a deficiency of bioactive UCP3L; UCP3L does not function primarily as a mitochondrial uncoupling protein.

Histologic features of lichen sclerosus et atrophicus in a surgical scar

A 76-year-old woman presented with a 7-mm, hard, pink nodule at the site of an appendectomy scar of more than 70 years' duration. The clinical impression at the time of biopsy was that of a keloid. Surprisingly, light microscopic examination revealed classic histologic features of late-stage lichen sclerosus et atrophicus (LSA) overlying a scar. Elastic tissue stain highlighted the unusual presence of abundant nodules of elastin in the reticular dermis only.

The long isoform uncoupling protein-3 (UCP3L) in human energy homeostasis

The biological role(s) proposed for UCP3 in energy homeostasis have been based primarily upon amino acid sequence homology to UCP1. Spontaneous mutations of UCP3> have been described in humans, but not in rodents. The functional consequences-or lack thereof-of these mutations in humans will be of great importance in elucidating the biology of this protein. The results of two such studies are summarized here.

Effects of obesity and stable weight reduction on UCP2 and UCP3 gene expression in humans

OBJECTIVES

The molecular determinants of energy expenditure are presently unknown. Recently, two uncoupling protein homologues, UCP2 and UCP3, have been identified. UCP2 is expressed widely, and UCP3 is expressed abundantly in skeletal muscle. Both could be important regulators of energy balance. In this paper, we investigated whether altered UCP2 and UCP3 mRNA levels are associated with obesity or weight reduction.

RESEARCH METHODS AND PROCEDURES

UCP2, UCP3 long and short mRNA levels were examined in skeletal muscle and in white adipose tissue of lean, obese, and weight-reduced individuals by RNase protection assay.

RESULTS

Expression of UCP2, UCP3S, and UCP3L mRNA in skeletal muscle was similar in lean individuals and in individuals with obesity at stable weight. In contrast, UCP3L and UCP3S mRNAs were decreased by 38% (p<0.0059) and 48% (p<0.0047), respectively, in 20% weight-reduced patients with obesity at stable weight. In contrast, UCP2 mRNA levels were increased by 30% in skeletal muscle of 20% weight-reduced subjects with obesity. In a different set of patients, mostly lean, UCP3L mRNA in skeletal muscle was decreased by 28% (p = 0.0425) after 10% weight reduction at stable weight. Expression of UCP2 mRNA in subcutaneous adipose tissue was similar in lean individuals and in individuals with obesity, and was increased by 58% during active weight loss.

DISCUSSION

Stabilization at reduced body weight in humans is associated with a decrease in UCP3 mRNA in muscle. It is possible that reduced UCP3 expression could contribute to decreased energy expenditure in weight-stable, weight-reduced individuals.

Effect of didanosine, stavudine, and hydroxyurea therapy on apoptosis in CD45RA+ and CD45RO+ T lymphocyte subpopulations

The effect of aggressive antiretroviral therapy on spontaneous apoptosis (AP) in CD4+ and CD8+ lymphocytes expressing CD45RO (memory cells) and CD45RA (naive cells) and their relationship to cellular activation and viral load were examined. Ten patients receiving simultaneous treatment with d4T, ddI, and HU were evaluated. Flow cytometric analysis showed significant levels of AP (measured by TUNEL assay) among memory and naive T cells and an enhanced expression of CD38 and HLA-DR activation markers. The percentage of apoptotic CD4+CD45RO+ and CD4+CD45RA+ cells decreased, respectively, from 34 +/- 3.3 and 29 +/- 3.6 prior to treatment to 20.5 +/- 4 and 22 +/- 3.8 at week 8 into therapy. The percentage of apoptotic CD8+CD45RO+ and CD8+CD45RA+ cells similarly decreased, respectively, from 20 +/- 2.5 and 24 +/- 3 prior to treatment to 14.5 +/- 2.7 and 16 +/- 3 at week 8 into treatment. The percentage of CD4+ cells expressing the activation markers CD38 and HLA-DR decreased from 27 +/- 6 to 13 +/- 2 and from 26 +/- 4 to 13.5 +/- 3, respectively. The percentage of CD8+ cells expressing either CD38 or HLA-DR fell from 22 +/- 3 to 10 +/- 2 for the former and from 39 +/- 5 to 22 +/- 4 for the latter. This was associated with a significant decrease in viral load (mean, 1.4 log10), and a decline in circulating plasma TNF-alpha and sIL-2R levels from 50.5 +/- 10 to 21 +/- 6 and 92.5 +/- 11 to 68 +/- 9, respectively. These data indicate that short-term therapy with ddI, d4T, and HU in combination diminished AP, immune activation, and partially restored naive and memory T cell subpopulations.