Cell-type specific molecular signatures of aging revealed in a brain-wide transcriptomic cell-type atlas

Biological aging can be defined as a gradual loss of homeostasis across various aspects of molecular and cellular function. Aging is a complex and dynamic process which influences distinct cell types in a myriad of ways. The cellular architecture of the mammalian brain is heterogeneous and diverse, making it challenging to identify precise areas and cell types of the brain that are more susceptible to aging than others. Here, we present a high-resolution single-cell RNA sequencing dataset containing ~1.2 million high-quality single-cell transcriptomic profiles of brain cells from young adult and aged mice across both sexes, including areas spanning the forebrain, midbrain, and hindbrain. We find age-associated gene expression signatures across nearly all 130+ neuronal and non-neuronal cell subclasses we identified. We detect the greatest gene expression changes in non-neuronal cell types, suggesting that different cell types in the brain vary in their susceptibility to aging. We identify specific, age-enriched clusters within specific glial, vascular, and immune cell types from both cortical and subcortical regions of the brain, and specific gene expression changes associated with cell senescence, inflammation, decrease in new myelination, and decreased vasculature integrity. We also identify genes with expression changes across multiple cell subclasses, pointing to certain mechanisms of aging that may occur across wide regions or broad cell types of the brain. Finally, we discover the greatest gene expression changes in cell types localized to the third ventricle of the hypothalamus, including tanycytes, ependymal cells, and Tbx3+ neurons found in the arcuate nucleus that are part of the neuronal circuits regulating food intake and energy homeostasis. These findings suggest that the area surrounding the third ventricle in the hypothalamus may be a hub for aging in the mouse brain. Overall, we reveal a dynamic landscape of cell-type-specific transcriptomic changes in the brain associated with normal aging that will serve as a foundation for the investigation of functional changes in the aging process and the interaction of aging and diseases.

Differential encoding of temporal context and expectation under representational drift across hierarchically connected areas

The classic view that neural populations in sensory cortices preferentially encode responses to incoming stimuli has been strongly challenged by recent experimental studies. Despite the fact that a large fraction of variance of visual responses in rodents can be attributed to behavioral state and movements, trial-history, and salience, the effects of contextual modulations and expectations on sensory-evoked responses in visual and association areas remain elusive. Here, we present a comprehensive experimental and theoretical study showing that hierarchically connected visual and association areas differentially encode the temporal context and expectation of naturalistic visual stimuli, consistent with the theory of hierarchical predictive coding. We measured neural responses to expected and unexpected sequences of natural scenes in the primary visual cortex (V1), the posterior medial higher order visual area (PM), and retrosplenial cortex (RSP) using 2-photon imaging in behaving mice collected through the Allen Institute Mindscope's OpenScope program. We found that information about image identity in neural population activity depended on the temporal context of transitions preceding each scene, and decreased along the hierarchy. Furthermore, our analyses revealed that the conjunctive encoding of temporal context and image identity was modulated by expectations of sequential events. In V1 and PM, we found enhanced and specific responses to unexpected oddball images, signaling stimulus-specific expectation violation. In contrast, in RSP the population response to oddball presentation recapitulated the missing expected image rather than the oddball image. These differential responses along the hierarchy are consistent with classic theories of hierarchical predictive coding whereby higher areas encode predictions and lower areas encode deviations from expectation. We further found evidence for drift in visual responses on the timescale of minutes. Although activity drift was present in all areas, population responses in V1 and PM, but not in RSP, maintained stable encoding of visual information and representational geometry. Instead we found that RSP drift was independent of stimulus information, suggesting a role in generating an internal model of the environment in the temporal domain. Overall, our results establish temporal context and expectation as substantial encoding dimensions in the visual cortex subject to fast representational drift and suggest that hierarchically connected areas instantiate a predictive coding mechanism.

Gumming Up The Works: Field Tests of a New Food-Grade Gum as Behavioral Disruptor for Drosophila suzukii (Diptera: Drosophilidae)

Drosophila suzukii Matsumura is an economically important pest of small and stone fruits. Its establishment in the Americas and Europe marked an important turning point in crop management programs. Ten years after its first detection, an effective integrated pest management program has yet to be developed and pesticides are mainly used to control this pest. Here we test a new behavioral control tool, with the aim to develop an alternative pest control strategy. A food-grade gum matrix, was evaluated under controlled and open field conditions for its ability to attract the pest and protect the ripening fruit. Here, we report that the gum effectively reduces fruit infestation when used under managed conditions. We show that a single point source can affect D. suzukii behavior over a 3.6 m radius and last for up to 21 d. Open field data reveal that the efficacy of the gum is significantly impacted by water content. We discuss these results in respect to the future implications for D. suzukii management, along with important considerations on gum mechanism of action, possible application strategies and economic suitability for growers.

Reproductive Site Selection: Evidence of an Oviposition Cue in a Highly Adaptive Dipteran, Drosophila suzukii (Diptera: Drosophilidae)

Drosophila suzukii (Matsumura) is a vinegar fly species that originates from Eastern Asia and has spread throughout Europe and the Americas since its initial detection in United States in 2008. Its relatively large, sclerotized, and serrated ovipositor enables the ability to penetrate ripening fruits, providing a protected environment for its egg and larval stages. Because the mechanism of oviposition site selection of D. suzukii is a matter of hypothesis, the aim of the present study was to elucidate behavioral and chemical aspects of short-range ovipositional site selection within the context of D. suzukii reproductive biology. The preference of D. suzukii to lay eggs on artificially pierced, previously infested, or intact fruits was tested. Video recordings and photographic evidence documented the release of an anal secretion over the fruit surface near the oviposition sites. Gas chromatographic analysis revealed the presence of 11 compounds detected only on the skin of egg-infested berries. Electroantennographic experiments with both sexes of D. suzukii highlighted the importance of six volatile compounds: methyl myristate, methyl palmitate, myristic acid, lauric acid, palmitic acid, and palmitoleic acid. Finally, a synthetic blend composed of the six compounds in a ratio similar to that found on the skin of egg-infested berries increased the oviposition rate of conspecific females. Data from our work suggest that the identified volatiles are cues for reproductive site selection. We discuss how these oviposition cues may affect the fitness of D. suzukii. The knowledge gained from this study may accelerate establishment of control strategies based on the interference and disruption of D. suzukii communication during the oviposition processes.

Effects of pregnancy on skin properties: A biomechanical approach

BACKGROUND

A woman's skin is dramatically affected by pregnancy. Its biomechanical properties are critical for resisting highly stressed areas. The aim of this work was to evaluate the impact of pregnancy on the mechanical properties of skin, as well as to evaluate the imprint that pregnancy leaves on the skin after delivery.

MATERIALS AND METHODS

Suction tests using a cutometer were performed on 15 non-pregnant women and 26 pregnant women at 8 months of pregnancy and 4 months after delivery. Areas of abdomen and thighs were studied.

RESULTS

Significant differences between the non-pregnant and 8-month pregnant groups were observed. Our data demonstrate that skin becomes less elastic and less deformable on the abdomen during pregnancy. On the thighs, a loss of elasticity and firmness was also observed. At 4 months after delivery, the skin did not return to its initial state.

CONCLUSION

This study showed that the mechanical properties of skin changed drastically during pregnancy compared to the non-pregnant condition and that these properties remain altered 4 months after delivery. In addition to alterations in abdominal skin during pregnancy, we also observed mechanical changes on the thighs, which are less subject to stretching.

Perceived and Valued Roles of Adults with Severe Mental Health Problems

The purpose of this article is to convey the findings of two studies related to the perception of past, present and future roles, the value attributed to these roles as well as the role patterns. Both studies were conducted with adults who have schizophrenia and are involved in a rehabilitation or work program. Data were collected from two sources: 1) secondary analysis of a study related to the methodology for validating the French translation (Hachey, Jumoorty, & Mercier, 1995) of the “Role Checklist”, (Barris, Oakley, & Kielhofner, 1988) and 2) a research project on the perception of roles and quality of life. Results showed that the dominant roles assumed by participants regardless of time were family member, friend, home maintainer and hobbyist. The most valued roles were those of friend, worker, and family member. The discussion will address the questions asked and elucidate the role patterns. The conclusion underlines the importance, for occupational therapists and health professionals, of including roles in the daily lives of their clients, taking into consideration the ones they value most highly.

Assessment of the in-plane biomechanical properties of human skin using a finite element model updating approach combined with an optical full-field measurement on a new tensile device

Human skin is one of the most important organ of the body. The assessment and knowledge of its properties are very useful for clinical or cosmetic research. Many techniques are used to measure the mechanical properties of this organ, like suction, indentation, torsion or tension tests. The aim of this paper is to present a new device based on tension technique and combining mechanical and optical measurements. The whole procedure used to assess the displacement field as described, and first results of tests performed in vivo are shown.

98 THE FETAL AND POSTNATAL EFFECTS OF PERICONCEPTIONAL HYPERGLYCEMIA USING A RABBIT MODEL

The objective of this study was to analyse the effects of maternal hyperglycemia during the periconception period on fetal and postnatal development using a rabbit model. Diabetes was induced in adult New Zealand female does by a single intravenous alloxan injection (group D). Glycemia was maintained between 3 and 5 g L–1 with 2 daily subcutaneous insulin injections. Does from group D and contemporary controls (group C) were naturally mated 1 wk after induction of diabetes in group D animals, without superovulation, and embryos collected after sacrifice on Day 4 post-coitum. In Expt. 1, embryos from D (n = 11) and C (n = 13) groups were transferred respectively to the right and left horns of 3 female recipients, which were killed on Day 28. In Expt. 2, 17 D and 16 C females were mated naturally. 68 D and 98 C embryos were collected and transferred to 26 non-diabetic recipients (6–7 embryos per doe). 17 females were pregnant with no difference between C and D recipients. Fetal development was monitored by ultrasound. At birth, litters were equilibrated in number. 15 D and 7 C pups (from 4 D and 2 C litters) were killed at weaning (1 month of age). The remaining 13 D and 26 C pups (4 D and 7 C litters) were allocated to 1 of 2 feeding groups: control or obesogenic diet. The obesogenic diet was based on the control diet supplemented with animal fat (suet, 200%) and glucose (200%). Bodyweight, adiposity, and glucose metabolism were monitored until sacrifice at 5 months of age. Data were analysed by ANOVA using litter (fetuses), litter and sex (weaning), and litter and diet (5 months) as co-factors. Sex effects at 5 months were not analysed due to small numbers of animals. Fetal development was not different between D and C groups. Fetal, placental, and fetal organ weights did not differ at Day 28, except for brain weight, which was significantly lower in D fetuses (0.86 ± 0.1 v. 1.05 ± 0.08 g; P < 0.05). There was no difference in litter size at birth (3.3 ± 0.3 v. 3.6 ± 0.5 pups for D and C groups, respectively; P = 0.5), but birthweight was significantly increased in D offspring (211 ± 6 v. 194 ± 6 g; P < 0.05). There was no difference in weight after 14 days. At 1 month of age, adiposity, plasma insulin and leptin concentrations were not different between groups. In contrast, in male D offspring, fasting glycemia was significantly lower (1.7 ± 0.2 v. 2.1 ± 0.02 g L–1; P < 0.01), plasma insulin-like growth factor 1 was significantly increased (P < 0.05) and kidney/bodyweight ratio was significantly reduced (0.41 ± 0.03 v. 0.45 ± 0.04; P < 0.01). From 12 wk of age, bodyweight became significantly different between D and C groups and according to diet (P < 0.005), with D individuals being lighter than C individuals for each dietary group. Finally, fasting glycemia was significantly higher in the animals fed the obesogenic diet (1.35 ± 0.05 v. 1.19 ± 0.05 g L–1; P < 0.04), regardless of group. These data suggest that maternal hyperglycemia during the periconceptional period affects glucose metabolism and organ development in offspring with sexual dimorphism.

1H and 13C NMR signal assignments of some new N,N'-diacyl proflavine derivatives

The complete 1H and 13C NMR signal assignments of 23 new N,N'-diacyl proflavine derivatives were achieved using one- and two-dimensional experiments (DEPT, HMQC and HMBC).

1H and 13C chemical shifts for acridines: Part XIX. N,N'-diacylproflavine derivatives

The 1H and 13C NMR resonances of 15 N,N'-diacylproflavines were assigned completely and unequivocally using a concerted application of one- and two-dimensional experiments (DEPT, gs-COSY, gs-HMQC and gs-HMBC).

3D behaviour of Frieden filters in confocal imaging

The three-dimensional (3D) focal behaviour of the super-resolving Frieden filters is investigated numerically. It is shown that, as the central bright spot is sharpened, super-giant secondary maximums are formed on the optic axis. These lobes are much higher that the well-known side-lobes inherent to spatial filtering that surround the restricted, utilisable field, whose characteristics in the meridional plane are depicted for various values of the space-bandwidth parameter and for various numbers of terms that compose the window function. The two-terms filter is found to present, for the first time to my knowledge, some axial apodizing properties. To be compatible with practical realisation, the use of this class of filters in a single- and two-photon confocally scanned system is discussed in terms of 3D super-resolution with an intentionally limited light-power loss. It is shown that these filters match particularly well with recently designed axial apodizers for the transmission-mode confocal scanning microscope and provide a 3D intensity point-spread volume reduction of variable amount as high as 37 percent. The filtering process is shown to vary significantly with the mode of operation.

[The Edinburgh Postnatal Depression Scale: the validity of its Quebec version for a population low socioeconomic status mothers]

This paper investigates the construct validity and reliability of a Quebec version of the Edinburgh Postnatal Depression Scale (EPDS) for a population of low-socioeconomic-status mothers. This scale was constructed for the specific purpose of measuring mothers' symptoms of depression during the postnatal period in an effort to alleviate the validity problems that could arise from depression scales intended for the general population. Two hundred and twenty-four mothers participating in a Quebec prevention program, "Naître égaux, grandir en santé" (Martin & Boyer, 1995) filled out the EPDS between the 22nd and the 35th day postpartum. A confirmatory factor analysis, conducted with LISREL, gives a 2-factor structure for the EPDS, the first representing symptoms of depression and the second symptoms of anxiety. This structure differs from the one presented by Cox, Holden, and Sagovsky (1987), authors of the EPDS. It corresponds, however to the results of other authors who looked at the EPDS with confirmatory factor analysis (Pop, Komproe, & van Son, 1992) and indicates a good construct validity. The reliability of the scale also appears satisfactory, with a Cronbach alpha co-efficient of 0.82.

Shock-wave-assisted ultrafast soliton generation

It is predicted numerically that soliton generation by four-wave mixing when the central wavelength of the initial pulse is below the zero-dispersion point of a nonlinear waveguide can be significantly boosted by shock-wave formation that reduces the launching power and extends the efficiency of that process deep inside the normal-dispersion region. Experimental evidence of the validity of this prediction is provided by spectral phase and intensity measurement of the propagated bound-state pulse.

[Recruitment of Montreal women of very low socioeconomic status for a randomized clinical study]

Studies show that it is difficult to recruit women of low socioeconomic status as clinical research participants. Such an objective was attained though as our results demonstrate in an evaluative study of a program implemented to lower the percentage of low birthweight in four CLSCs of the Island of Montreal between 1994 and 1996. The global recruitment strategy enabled us to reach 56.2% of our goal in 1994 and 77.4% in 1996. Two conclusions can be drawn from this result: the effectiveness of the three methods of recruitment varied according to each participating CLSC, and the global strategy, combined with the mobilization of community resources, was successful in enrolling women of low socioeconomic status.

[Recruitment of Montreal women of very low socioeconomic status for a randomized clinical study]

Studies show that it is difficult to recruit women of low socioeconomic status as clinical research participants. Such an objective was attained though as our results demonstrate in an evaluative study of a program implemented to lower the percentage of low birthweight in four CLSCs of the Island of Montreal between 1994 and 1996. The global recruitment strategy enabled us to reach 56.2% of our goal in 1994 and 77.4% in 1996. Two conclusions can be drawn from this result: the effectiveness of the three methods of recruitment varied according to each participating CLSC, and the global strategy, combined with the mobilization of community resources, was successful in enrolling women of low socioeconomic status.

An evaluation of psychometric properties of the client's questionnaire of the Wisconsin Quality of Life Index-Canadian version (CaW-QLI)

Psychometric properties of Client's questionnaire from the Canadian version of the Wisconsin Quality of Life-Index (CaW-QLI) were assessed with two groups, 89 English (E) and 94 French (F) individuals with schizophrenia or schizoaffective disorder. Sub-samples of 40 E and 36 F were re-interviewed within a 2-week period. Spearman correlations-SC between each domain and CaW-QLI global Score ranged from 0.39 to 0.76, while interdomain correlations were low, confirming the multi-dimensional properties of the scale. Cronbach's alpha (internal consistency) were 0.78 (E) and 0.70 (F) for the CaW-QLI global scores and, from 0.45 to 0.88 among seven of eight domains. Test-retest (Concordance Correlation Coefficient--CCC) ranged from 0.36 to 0.80 among the domains, and from 0.80 (E) and 0.85 (F) between CaW-QLI global scores. Regarding convergent validity, SC between CaW-QLI global score and Spitzer's QOL-Index were 0.72 (E) and 0.58 (F). As hypothesized, there were higher correlations between CaW-QLI global scores (E and F) and SF-36 scales related to mental health than those related to physical health. Minor changes in the scoring are proposed to enhance face and content validity.

High-power femtosecond-pulse reshaping near the zero-dispersion wavelength of an optical fiber

Nonlinear propagation of high-power femtosecond pulses close to the zero-dispersion wavelength of a singlemode optical fiber is studied experimentally and numerically. The roles of four-photon mixing, stimulated Raman scattering, and self-steepening in this process are represented through different extensions of the nonlinear Schrödinger equation.

[Perception of social support given by health professionals according to the participants in a prenatal prevention program who live in extreme poverty]

One of the essential elements of the "Programme intégré de prévention en périnatalité--Naître-égaux-Grandir-en-san t" (Born Equal--Brought up Healthy) is to have a health professional offering general support to pregnant women living in poverty. This research is based on a secondary analysis of the transcriptions of interviews done in order to implement the program. The thematic content analysis was employed to analyze the women's perception of the support provided by the health professional, the relationship between client-professional, and the perceptions of these women about the impact that the social support had on their pregnancy experience. The categories of support that emerged from the analysis are: information support, emotional support, instrumental support, changing life style support, recreational support, and availability of support. The categories of impact perceived by the participants are: learning, changes in life style, to be in a good mood, and the use of community resources. A key element in the perception of support by the participants is the establishment of a relationship of trust between professional and client. This relationship of trust is important to the development of intimacy and to foster the perception of a more intense kind of support. Hence social support and the relationship of trust work in synergy and reinforce each other.

T-cell receptor polymorphisms in Tlingit Indians with rheumatoid arthritis

Rheumatoid arthritis (RA) develops as a result of the interaction of both genetic and environmental factors. Among the genes in humans that have been suggested as candidate susceptibility genes in RA are those encoding the T cell receptor for antigen (TCR). A high prevalence and early age of onset of RA has previously been reported in Alaskan Tlingit Indians. In this study, the frequency of seven different restriction fragment length polymorphisms (RFLPs) in the TCR alpha and beta gene complexes were measured in a population of Alaskan Tlingit Indians. No statistically significant differences were noted when the frequencies of these RFLPs were compared between Tlingits with RA and healthy controls (p > 0.05). These results do not support the hypothesis of an RA-susceptibility allele in the vicinity of these TCR alpha or beta genes. Since TCR RFLPs have not been extensively studied in native American populations, TCR polymorphism frequencies in the Tlingits were also compared to the frequencies observed in a second control group of healthy Caucasians. Statistically significant differences were observed in these comparisons implying a different distribution of individuals in these populations with different TCR repertoires.

[In vitro activity of glycopeptides on 114 coagulase-negative staphylococci: problems with the teicoplanin diffusion test, "alert" parameters indicating need for MIC determination]

The activity of vancomycin (Va) and teicoplanin (Tc) against 114 coagulase-negative staphylococci (CNS) strains was evaluated by disk-diffusion and agar dilution minimal inhibitory concentration (MIC) determination. Results were analysed by species and methicillin-resistance (MR) status. MICs for Va were in the susceptible range (< 4 mg/l) for all strains, with inhibition zone diameters of 17 mm or more in every case. MICs for teicoplanin were 8 or 16 mg/l for 19 CNS strains (including 18 with MR) of which 14 yielded an inhibition zone diameter of 17 mm or more (false susceptibility). Parameters which should lead to MIC determination for Tc regardless of disk diffusion findings include the species (S. haemolyticus), methicillin resistance, Tc zone diameter, and an at least 3 mm difference between the Va and Tc zone diameters.

[Activity of ethambutol, isoniazid and rifampicin on Corynebacterium urealyticum and Corynebacterium jeikeium]

Because corynebacteria and mycobacteria have walls of similar composition, it was of interest to test the effects on resistant corynebacteria of two agents with anti-wall effects, i.e., ethambutol (EMB) and isoniazid (INH). Rifampicin was also studied to extend previous data and clarify conflicting results in the literature. INH was not active in levels achieved in vivo with standard dosages. The minimal inhibitory concentration (MIC) of EMB was under serum levels for only three of 78 strains. All minimal bactericidal concentration (MBCs) were greater than serum levels. With RIF, 59% of strains were susceptible and 19.2% exhibited intermediate susceptibility as defined by the French Committee on Antimicrobial Susceptibility Testing. CMI and CMB distributions were heterogeneous, suggesting a possible acquired heterogeneous resistance to RIF.

HLA antigens in Tlingit Indians with rheumatoid arthritis

HLA-DR4 has been described in association with rheumatoid arthritis (RA) in multiple populations. We have studied HLA antigens in Alaskan Tlingit Indians. HLA-DR4 was decreased in the RA group (n = 32) compared with controls (n = 62) (6% vs 21% p = 0.07). The predominant DR4 allele observed was DRB1*0403 (Dw13.1). The most striking observation in these studies was a marked predominance of the DRB1*1402 allele encoding Dw16 (DRw14). This allele was present in 91% of RA cases, but was also highly prevalent in controls (80%, OR = 2.4 p = 0.20). DRB1*1402 only was observed in 47% of cases and 31% of controls. The DRB3*0101 (DRw52), and the DQA*0501 and DQB*0301 alleles encoding a subset of DQw3 were associated with DRB1*1402 in cases and in controls. HLA-Bw62 was increased in RA cases (28%) compared with controls (8%) (OR = 4.5, p = 0.01, corrected p = ns).