Connectome-driven neural inventory of a complete visual system

Vision provides animals with detailed information about their surroundings, conveying diverse features such as color, form, and movement across the visual scene. Computing these parallel spatial features requires a large and diverse network of neurons, such that in animals as distant as flies and humans, visual regions comprise half the brain's volume. These visual brain regions often reveal remarkable structure-function relationships, with neurons organized along spatial maps with shapes that directly relate to their roles in visual processing. To unravel the stunning diversity of a complex visual system, a careful mapping of the neural architecture matched to tools for targeted exploration of that circuitry is essential. Here, we report a new connectome of the right optic lobe from a male Drosophila central nervous system FIB-SEM volume and a comprehensive inventory of the fly's visual neurons. We developed a computational framework to quantify the anatomy of visual neurons, establishing a basis for interpreting how their shapes relate to spatial vision. By integrating this analysis with connectivity information, neurotransmitter identity, and expert curation, we classified the ~53,000 neurons into 727 types, about half of which are systematically described and named for the first time. Finally, we share an extensive collection of split-GAL4 lines matched to our neuron type catalog. Together, this comprehensive set of tools and data unlock new possibilities for systematic investigations of vision in Drosophila, a foundation for a deeper understanding of sensory processing.

A connectome and analysis of the adult Drosophila central brain

The neural circuits responsible for animal behavior remain largely unknown. We summarize new methods and present the circuitry of a large fraction of the brain of the fruit fly Drosophila melanogaster. Improved methods include new procedures to prepare, image, align, segment, find synapses in, and proofread such large data sets. We define cell types, refine computational compartments, and provide an exhaustive atlas of cell examples and types, many of them novel. We provide detailed circuits consisting of neurons and their chemical synapses for most of the central brain. We make the data public and simplify access, reducing the effort needed to answer circuit questions, and provide procedures linking the neurons defined by our analysis with genetic reagents. Biologically, we examine distributions of connection strengths, neural motifs on different scales, electrical consequences of compartmentalization, and evidence that maximizing packing density is an important criterion in the evolution of the fly's brain.

Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life

This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age.

INTRODUCTION

The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking.

METHODS

Twenty-six healthy older subjects (age, 74.1 ± 3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2 ± 4.4; SPPB score ≤9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively.

RESULTS

At 3-year follow-up, muscle cross-sectional area (CSA) (p < 0.013) and power decreased (p < 0.001), while intermuscular fat infiltration increased (p < 0.001). These decrements were accompanied with a longer time to complete 400 m by 22 ± 46 s (p < 0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p < 0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p < 0.020), muscle CSA (p < 0.046), and increased 400 m walk time (p < 0.003).

CONCLUSIONS

In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical performance contribute independently to increase FoF, while declines of muscle mass and physical performance contribute to deterioration of QoL. These findings provide further rationale for developing interventions to improve aging muscle health.

Model development for O(2) and N(2) permeation rates through CZ-resin vials

The headspace of vials containing oxygen-sensitive formulations is filled with a nitrogen blanket. This paper presents the development of a mathematical model to predict the oxygen and nitrogen permeation rates through the walls of plastic CZ-resin vials. The model estimates the time required for a nitrogen-filled vial to reach ambient nitrogen and oxygen levels. The permeation of oxygen and nitrogen through the vial is governed by Fick's law and may be described by an exponential equation. Using the values for oxygen and nitrogen permeation through CZ-resin vial, the half-lives for the decrease in nitrogen level and increase in oxygen level was found to be 150 days and 15 days, respectively. This result can be attributed to the greater permeability of CZ-resin vial to oxygen (79.06 cm(3)-mm/m(2)-24 h-atm) when compared with nitrogen (12 cm(3)-mm/m(2)-24 h-atm). The ingress of oxygen into CZ-resin vials was determined experimentally and it was found to verify the model. These results indicate that CZ-resin vials may be inappropriate for packaging oxygen-sensitive formulations even in the presence of a nitrogen-filled headspace.

Physicochemical stability of crystalline sugars and their spray-dried forms: dependence upon relative humidity and suitability for use in powder inhalers

Lactose, trehalose, sucrose, and mannitol were purchased in crystalline form and fractionated by sieving. Coarse (125-212 microns) and fine (44-74 microns) free-flowing fractions were selected as typical of drug carriers in dry-powder inhalers. In addition, one batch of each sugar was spray-dried to form a respirable powder (> 50% [w/w], < 5 microns). Both fractions and the spray-dried powders were characterized before and after storage for 30 days at < 23%, 23%, 52%, 75% and 93% relative humidity (RH) at 25 degrees C. Moisture uptake was determined by thermogravimetric analysis (TGA) validated by Karl Fischer titration. Sieve fractions (before storage at different RHs) and spray-dried materials (before and after storage) were further characterized by differential scanning calorimetry (DSC) and x-ray powder diffraction (XRPD). All crystalline sieve fractions (except sucrose at 93% RH) were stable at 25 degrees C and showed insignificant moisture uptake when exposed to each relative humidity for 30 days. Sucrose dissolved in sorbed moisture at 93% RH. Spray-dried lactose, sucrose, and trehalose, which were collected in the amorphous form, showed moisture uptake, without recrystallization, when held for 30 days at 23% RH. These sugars recrystallized as sintered masses and became undispersible at > or = 52% RH. Spray-dried mannitol was apparently 100% crystalline when collected directly from the spray-dryer; it did not show humidity-induced changes. The physicochemical behavior of each sugar form is discussed as it relates to the sugar's suitability as a powder-inhaler excipient, with both conventional and protein drugs.

A dynamic test of lower extremity function following anterior cruciate ligament reconstruction and rehabilitation

It is essential to assess the functional status of patients with surgically reconstructed and rehabilitated anterior cruciate ligaments prior to discharge. This study established a testing paradigm for functional force production and absorption. Data were obtained from 100 healthy subjects for maximal hops, controlled leaps, and hopping and leaping symmetry. Only 10% of symptomatic patients met maximal hopping criteria, while 15% achieved controlled leaping norms. Ninety-five percent of these patients failed to reach both hopping and leaping symmetry norms. Asymptomatic patients were 63% successful in meeting hopping criteria, and 57% were successful in meeting leaping criteria. Hop symmetry and leap symmetry were achieved at rates of 70% and 60%, respectively. The performance of both groups fell significantly below that of normal subjects (p < .05). Data suggest that this protocol does accurately assess functional and dysfunctional knees, and that force absorption may be more critical than force production in the determination of functional capacity.

The endocrine investigation of disorders of sodium and water homeostasis

This article reviews critically the investigation of polyuric states, hyponatremia with particular emphasis on the syndrome of inappropriate antidiuretic hormone secretion, and primary hyperaldosteronism. Details of some essential tests are given with comments on interpretation of results.

Osmoregulation of vasopressin and thirst: comparison of 20% mannitol with 5% saline as osmotic stimulants in healthy man

OBJECTIVE

Osmoregulation is normally studied using a 5% saline infusion. This may be deleterious in fluid overloaded patients. Twenty per cent mannitol is another osmotic stimulant. This study aimed to compare 20% mannitol infusion with 5% saline as an osmotic stimulant to thirst and vasopressin secretion in normal volunteers.

DESIGN AND PATIENTS

Eight healthy volunteers studied on 2 occasions in random order. Each study involved a 2-hour infusion period of either hypertonic (5%) saline (0.06 ml/kg/h) or hypertonic (20%) mannitol (0.07 ml/kg/h).

MEASUREMENTS

Plasma vasopressin (pVp), plasma sodium, plasma osmolality (pOsm), haematocrit (HCT), blood pressure, thirst, blood glucose and volume drunk at end of infusion.

RESULTS

Five per cent saline infusion stimulated significantly higher levels of pOsm, pVp and thirst than 20% mannitol. Plasma sodium rose significantly during 5% saline infusion and fell during 20% mannitol infusion. HCT fell and mean arterial pressure rose in both infusions but the changes were not clinically significant. Piecewise linear regression analysis defined the overall threshold for pVp release for the two solutions as 5% saline, 292 mosm/kg and 20% mannitol, 291 mosm/kg, and the post threshold slope as 5% saline, 0.46 pmol/l pVp per mosm and 20% mannitol, 0.30 pmol/l pVp per mosm. The threshold for thirst onset was 5% saline, 291 mosm/kg and 20% mannitol, 290 mosm/kg, and the post threshold slope, 5% saline, 0.58 cm thirst per mosm and 20% mannitol, 0.28 cm thirst per mosm. The differences between the calculated osmotic thresholds and slopes post threshold for the two infusions were not significant for the pVp versus pOsm relationship. The difference between the cumulative volume drunk following the two infusions did not reach statistical significance. Mannitol caused a significant diuresis.

CONCLUSIONS

Twenty per cent mannitol infusion is an effective osmotic stimulant to thirst and vasopressin release in normal individuals, but is less potent than 5% saline infusion.

Optimized inhalation aerosols. II. Inertial testing methods for particle size analysis of pressurized inhalers

Pressurized metered dose inhaler (MDI) output from three different albuterol formulations was characterized using three inertial separation devices. Results were compared for the Delron six-stage cascade impactor (DC16), the Andersen Mark II eight-stage impactor (AC18), and Copley's twin-stage liquid impinger (LI). None of the devices tested in this study was ideal in all respects. All devices could differentiate between formulations in terms of respirable doses (albuterol amount with aerodynamic diameters less than 5.5 through 6.4 microns). Only the high-flow rate LI could differentiate among all three formulations when data were presented in terms of respirable percentage (RP) of drug collected. Values for RP were in excellent agreement for the independently calibrated impactors when the same evaporation chamber was used atop the impactors. The LI appeared to overestimate values for RP in vivo. Results are discussed in light of the debate surrounding the revision of USP aerosol testing requirements. Rigorous specifications for evaporation chambers and methodologies are necessary for meaningful inter- and intra-laboratory comparison of results when any of these devices are used.

Endoscopic retrieval of miniature battery

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Whole blood 5 -hydroxytryptamine during treatment of endogenous depressive illness

In the course of a study on endogenous depressive illness, whole blood 5-hydroxytryptamine (5HT) has been recorded in sixteen in-patients at Roffey Park Hospital. Thirteen patients received L-tryptophan 1 G t.d.s. and 3 G nocte, of whom two received in addition phenelzine 15 mg. b.d. for 48 hours followed by 30 mg. b.d. thereafter. Three patients received amitriptyline 25 mg. b.d. and 50 mg. nocte for 48 hours followed by 50 mg. b.d. and 75 mg. nocte thereafter. One patient receiving Ltryptophan had essential hypertension and received α-methylDOPA throughout. Observation continued for six weeks.

Comparison of propranolol and Ro 3-3528 in hyperthyroid tachycardia and dysrhythmias

Ro 3-3528, a non-selective β-adrenoceptor blocking drug which lacks intrinsic activity, produces a dose-response effect in hyperthyroid tachycardia, and shows no dysrhythmic properties. In hyperthyroid patients, β-blocking drugs of this nature are preferable to those possessing intrinsic sympathomimetic activity, which may have dysrhythmic properties in this condition.