Neighborhood disadvantage and parenting predict longitudinal clustering of uncinate fasciculus microstructural integrity and clinical symptomatology in adolescents

Parenting behaviors and neighborhood environment influence the development of adolescents' brains and behaviors. Simultaneous trajectories of brain and behavior, however, are understudied, especially in these environmental contexts. In this four-wave study spanning 9-18 years of age (N=224 at baseline, N=138 at final assessment) we used longitudinal k-means clustering to identify clusters of participants with distinct trajectories of uncinate fasciculus (UF) fractional anisotropy (FA) and anxiety symptoms; we examined behavioral outcomes and identified environmental factors that predicted cluster membership. We identified three clusters of participants: 1) high UF FA and low symptoms ("low-risk"); 2) low UF FA and high symptoms ("high-risk"); and 3) low UF FA and low symptoms ("resilient"). Adolescents in disadvantaged neighborhoods were more likely to be in the resilient than high-risk cluster if they also experienced maternal warmth. Thus, neighborhood disadvantage may confer neural risk for psychopathology that can be buffered by maternal warmth, highlighting the importance of considering multiple environmental influences in understanding emotional and neural development in youth.

Kir4.1-Dependent Astrocyte-Fast Motor Neuron Interactions Are Required for Peak Strength

Diversified neurons are essential for sensorimotor function, but whether astrocytes become specialized to optimize circuit performance remains unclear. Large fast α-motor neurons (FαMNs) of spinal cord innervate fast-twitch muscles that generate peak strength. We report that ventral horn astrocytes express the inward-rectifying K⁺ channel Kir4.1 (a.k.a. Kcnj10) around MNs in a VGLUT1-dependent manner. Loss of astrocyte-encoded Kir4.1 selectively altered FαMN size and function and led to reduced peak strength. Overexpression of Kir4.1 in astrocytes was sufficient to increase MN size through activation of the PI3K/mTOR/pS6 pathway. Kir4.1 was downregulated cell autonomously in astrocytes derived from amyotrophic lateral sclerosis (ALS) patients with SOD1 mutation. However, astrocyte Kir4.1 was dispensable for FαMN survival even in the mutant SOD1 background. These findings show that astrocyte Kir4.1 is essential for maintenance of peak strength and suggest that Kir4.1 downregulation might uncouple symptoms of muscle weakness from MN cell death in diseases like ALS.

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Kir4.1 is upregulated in astrocytes around high-activity alpha motor neurons (MNs)

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Astrocyte Kir4.1 KO caused decreased peak strength without alpha MN loss

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ALS patient-derived astrocytes show cell-autonomous Kir4.1 downregulation

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Astrocyte Kir4.1 regulates MN size through PI3K/mTOR/pS6 activation

Astrocyte-derived interleukin-33 promotes microglial synapse engulfment and neural circuit development

Neuronal synapse formation and remodeling are essential to central nervous system (CNS) development and are dysfunctional in neurodevelopmental diseases. Innate immune signals regulate tissue remodeling in the periphery, but how this affects CNS synapses is largely unknown. Here, we show that the interleukin-1 family cytokine interleukin-33 (IL-33) is produced by developing astrocytes and is developmentally required for normal synapse numbers and neural circuit function in the spinal cord and thalamus. We find that IL-33 signals primarily to microglia under physiologic conditions, that it promotes microglial synapse engulfment, and that it can drive microglial-dependent synapse depletion in vivo. These data reveal a cytokine-mediated mechanism required to maintain synapse homeostasis during CNS development.

Effective-medium theory of elastic waves in random networks of rods

We formulate an effective medium (mean field) theory of a material consisting of randomly distributed nodes connected by straight slender rods, hinged at the nodes. Defining wavelength-dependent effective elastic moduli, we calculate both the static moduli and the dispersion relations of ultrasonic longitudinal and transverse elastic waves. At finite wave vector k the waves are dispersive, with phase and group velocities decreasing with increasing wave vector. These results are directly applicable to networks with empty pore space. They also describe the solid matrix in two-component (Biot) theories of fluid-filled porous media. We suggest the possibility of low density materials with higher ratios of stiffness and strength to density than those of foams, aerogels, or trabecular bone.

Is the Patient Outcomes Of Surgery (POS)-Hand/Arm questionnaire a reliable, valid and responsive measurement of patient-based outcomes in hand and upper limb surgery?

The purpose of our study was to evaluate a new region-specific outcome measure in hand and upper limb surgery: the Patient Outcomes of Surgery (POS)-Hand/Arm questionnaire using the generic Short Form Health Survey (SF)-36 questionnaire as a 'gold standard' comparative measure. The POS-Hand/Arm preop questionnaire and the SF-36 questionnaire were completed by 214 patients on the day of their hand or upper limb surgery; and a postop POS-Hand/Arm and the SF-36 questionnaire were completed by patients 3 months after their initial surgery. The POS-Hand/Arm questionnaire responses were psychometrically evaluated and it was shown to have high internal consistency; high total-item correlations; signification scale correlations with the SF-36; and a low proportion of missing data. The POS-Hand/Arm questionnaire is a psychometrically sound instrument that can be used pre- and post-surgery to evaluate patient-based outcomes for a wide range of conditions in hand and upper limb surgery.

Reliability of handheld Doppler in planning local perforator-based flaps for extremities

BACKGROUND

The perforator-based flap is one of the most common and frequently used options for soft tissue reconstruction on extremities to remedy small to medium-size defects. A Doppler probe has been used to identify these perforators for the designing of the flap base, axis and dimensions. The reliability of the handheld Doppler was assessed for its sensitivity and positive predictive values.

METHODS

A prospective study on upper and lower extremities was designed, and 14 volunteers were selected for the study. A handheld Doppler with 8- and 10-MHz probes was used, and the volunteers were subsequently scanned using a color duplex with a linear-array probe of 7 and 10 MHz. A total of 94 perforators were identified on the back of the hand, wrist, and distal 24 cm of the leg.

RESULTS

The 49 perforators marked on 10 legs produced 40 correct, 3 false-positive, and 6 false-negative results. The 33 distal intermetacarpal perforators marked on the back of 11 hands yielded 26 correct, 5 false-positive, and 2 false-negative results. The 12 dorsal carpal arch perforators marked gave 6 correct and 6 false-positive results.

CONCLUSION

Unidirectional flowmetry using a handheld Doppler is a practical and reliable method for identifying skin perforators. It can be used to plan and design a flap for soft tissue defect reconstruction of extremities in selected cases. The reliability of its use is size dependent, and vessels with a smaller diameter showed unacceptably high false-positive results.

Adherence to antiretroviral therapy in rural persons living with HIV disease in the United States

The current study delineated patterns and predictors of adherence to antiretroviral therapy in 329 persons living with HIV disease in rural areas of 12 US states. Participants provided self-report data on patterns of HIV medication adherence, reasons for missing medication doses, psychological symptomatology, life-stressor burden, social support, ways of coping, coping self-efficacy, the quality of their relationship with their main physician, and barriers to health care and social services. Based on adherence data collected via retrospective, self-report assessment instruments, only 50% of participants adhered consistently to antiretroviral therapy regimens in the past week. Consistent adherence was more common in White participants, persons who had progressed to AIDS, and 'native infections' (i.e. persons who were born, raised, and infected in their current place of residence). Logistic regression analyses indicated that consistent adherence was reported by persons who drank less alcohol, had a good relationship with their main physician, and engaged in more active coping in response to HIV-related life stressors. As the number of rural persons living with HIV disease continues to increase, research that identifies correlates of non-adherence and conceptualizes approaches to optimize adherence in this group is urgently needed.

Transmural variation of myocardial attenuation measured with a clinical imager

The objective of this study was to quantify the transmural variation in attenuation for the septal and lateral walls of the heart. Our approach was to utilize a commercially available ultrasonic imaging system to acquire images of excised sections of eight sheep hearts with an orientation similar to that encountered in the apical four-chamber view. The measured values (mean +/-SE) of the slope of attenuation for the transmural regions of the septum are: 1.40 +/-0.11, 0.99 +/-0.09, and 1.85 +/-0.16 (dB/cm/MHz) for the left subendocardial, midmyocardial, and right subendocardial zones, respectively. The analogous data from the lateral wall are: 1.42 +/-0.11, 0.83 +/-0.07, and 1.20 +/- 0.16 (dB/cm/MHz) for the subendocardial, midmyocardial, and subepicardial zones, respectively. These data demonstrate that ultrasonic attenuation associated with the septum and the lateral wall, when imaged in a manner similar to that of the apical four-chamber view, is anisotropic.

Ultrasonic tissue characterization: review of an approach to assess hypertrophic myocardium

It is well known that left ventricular hypertrophy is associated with increased cardiovascular morbidity and mortality. Recently, there has been considerable interest in the application and refinement of noninvasive diagnostic techniques for identification of myocardial tissue composition to permit differentiation between left ventricular hypertrophy that may be associated with irreversible, and therefore, possibly adverse, collagen accumulation ("pathological hypertrophy") as opposed to the type of possibly "benign" hypertrophy devoid of such characteristics (i.e., "physiological hypertrophy"). We review the current state of knowledge in the application of ultrasonic tissue characterization that addresses this question with respect to left ventricular myocardium.

Fingerprinting of polysaccharides attacked by hydroxyl radicals in vitro and in the cell walls of ripening pear fruit

Hydroxyl radicals (*OH) may cause non-enzymic scission of polysaccharides in vivo, e.g. in plant cell walls and mammalian connective tissues. To provide a method for detecting the action of endogenous *OH in vivo, we investigated the products formed when polysaccharides were treated with *OH (generated in situ by ascorbate-H(2)O(2)-Cu(2+) mixtures) followed by NaB(3)H(4). Treatment with *OH increased the number of NaB(3)H(4)-reacting groups present in citrus pectin, homogalacturonan and tamarind xyloglucan. This increase is attributed partly to the formation of glycosulose and glycosulosuronic acid residues, which are then reduced back to the original (but radioactive) sugar residues and their epimers by NaB(3)H(4). The glycosulose and glycosulosuronic acid residues were stable for >16 h at 20 degrees C in ethanol or buffer (pH 4.7), but were destroyed in alkali. Driselase-digestion of the radiolabelled polysaccharides yielded characteristic patterns of (3)H-products, which included galactose and galacturonate from pectin, and isoprimeverose, galactose, glucose and arabinose from xyloglucan. Pectin yielded at least eight (3)H-labelled anionic products, separable by electrophoresis at pH 3.5. The patterns of radioactive products form useful 'fingerprints' by which *OH-attacked polysaccharides may be recognized. Applied to the cell walls of ripening pear (Pyrus communis) fruit, the method gave evidence for progressive *OH radical attack on polysaccharides during the softening process.