Impact on Health Care Utilization and Costs of a Medicaid Community Health Worker Program in Detroit, 2018-2020: A Randomized Program Evaluation.

Objectives. To compare health care utilization and costs between beneficiaries randomly assigned to usual services versus a community health worker (CHW) program implemented by 3 Medicaid health plans. Methods. From February 2018 to June 2019, beneficiaries residing in Detroit, Michigan's Cody Rouge neighborhood with more than 3 emergency department (ED) visits or at least 1 ambulatory care‒sensitive hospitalization in the previous 12 months were randomized. CHWs reached out to eligible beneficiaries to assess their needs and link them to services. We compared ED and ambulatory care visits, hospitalizations, and related costs over 12 months. Results. In intention-to-treat analyses among 2457 beneficiaries, the 1389 randomized to the CHW program had lower adjusted ratios of ED visits (adjusted rate ratio [ARR] = 0.96; P < .01) and ED visit costs (ARR = 0.96; P < .01), but higher adjusted ratios of ambulatory care costs (ARR = 1.15; P < .01) and no differences in inpatient or total costs compared with the usual-care group. Conclusions. Initial increases in ambulatory care use from effective programs for underserved communities may mitigate savings from decreased acute care use. Longer-term outcomes should be followed to assess potential cost savings from improved health. Trial Registration: ClinicalTrials.gov identifier: NCT03924713. (Am J Public Health. 2022;112(5):766-775. https://doi.org/10.2105/AJPH.2021.306700).

Texture coding in the rat whisker system: slip-stick versus differential resonance.

Rats discriminate surface textures using their whiskers (vibrissae), but how whiskers extract texture information, and how this information is encoded by the brain, are not known. In the resonance model, whisker motion across different textures excites mechanical resonance in distinct subsets of whiskers, due to variation across whiskers in resonance frequency, which varies with whisker length. Texture information is therefore encoded by the spatial pattern of activated whiskers. In the competing kinetic signature model, different textures excite resonance equally across whiskers, and instead, texture is encoded by characteristic, nonuniform temporal patterns of whisker motion. We tested these models by measuring whisker motion in awake, behaving rats whisking in air and onto sandpaper surfaces. Resonant motion was prominent during whisking in air, with fundamental frequencies ranging from approximately 35 Hz for the long Delta whisker to approximately 110 Hz for the shorter D3 whisker. Resonant vibrations also occurred while whisking against textures, but the amplitude of resonance within single whiskers was independent of texture, contradicting the resonance model. Rather, whiskers resonated transiently during discrete, high-velocity, and high-acceleration slip-stick events, which occurred prominently during whisking on surfaces. The rate and magnitude of slip-stick events varied systematically with texture. These results suggest that texture is encoded not by differential resonant motion across whiskers, but by the magnitude and temporal pattern of slip-stick motion. These findings predict a temporal code for texture in neural spike trains.

Narrating the Transition to Adulthood for Youth in Uganda: Leaving School, Mobility, Risky Occupations, and HIV.

School enrollment, mobility, and occupation are each important factors to consider when examining HIV (human immunodeficiency virus) infection risk among youth in sub-Saharan Africa. Through an analysis of narrative life histories from 30 HIV-positive and 30 HIV-negative youth (aged 15-24 years), matched on gender, age, and village and purposively selected and interviewed from the Rakai Community Cohort Study, this article shows the complex connection between leaving school, mobility, and occupation with implications for HIV risk. We identified a pattern of risk factors that was present in many more HIV-positive than HIV-negative youth life stories. These HIV-positive youth shared a similar pathway during their transition to adulthood: After leaving school, they moved in search of occupations; they then engaged in risky occupations before eventually returning to their home village. Linking the lines of inquiry on school enrollment, mobility, and risky occupations, our findings have important implications for adolescent health research, practice, and policy in Uganda and across sub-Saharan Africa and the developing world.

Study protocol for a Community Health Worker (CHW)-led comprehensive neighborhood-focused program for medicaid enrollees in detroit.

Residents of low income neighborhoods disproportionately experience poor health, and many have unmet social needs. Clinical trials have shown the efficacy of Community Health Worker (CHW) programs in improving outcomes for a variety of health conditions. An important next step is developing and evaluating financially sustainable CHW program models in real-life settings. This program evaluation examines health care utilization among participants in a geographically targeted program led by salaried CHWs from three Medicaid health plans. Beneficiaries who reside in the Cody Rouge neighborhood of Detroit and had more than 3 Emergency Department (ED) visits or at least 1 ambulatory care-sensitive hospitalization in the prior 12 months are eligible for the program. Health plan CHWs assigned to the program reach out to eligible beneficiaries to provide an assessment; link them to resources; and provide follow-up. At 12-month follow up, claims data on ED visits, ambulatory care-sensitive hospitalizations, primary care visits, and related costs will be compared between beneficiaries who participated and eligible beneficiaries randomized to receive usual outreach. We hypothesize that patients enrolled in the CHW intervention will experience a reduction in acute care usage resulting in cost savings compared to those receiving usual health plan outreach. This study is among the first to evaluate the impact on health care utilization of augmented services delivered by health plan CHWs for high-utilizing health plan members as part of a health plan-community-academic partnership. This study will provide important information on CHW program sustainability and provide insights into effective implementation of such programs. TRIAL REGISTRATION: NCT03924713.

Social protection: potential for improving HIV outcomes among adolescents.

INTRODUCTION: Advances in biomedical technologies provide potential for adolescent HIV prevention and HIV-positive survival. The UNAIDS 90-90-90 treatment targets provide a new roadmap for ending the HIV epidemic, principally through antiretroviral treatment, HIV testing and viral suppression among people with HIV. However, while imperative, HIV treatment and testing will not be sufficient to address the epidemic among adolescents in Southern and Eastern Africa. In particular, use of condoms and adherence to antiretroviral therapy (ART) remain haphazard, with evidence that social and structural deprivation is negatively impacting adolescents' capacity to protect themselves and others. This paper examines the evidence for and potential of interventions addressing these structural deprivations. DISCUSSION: New evidence is emerging around social protection interventions, including cash transfers, parenting support and educational support ("cash, care and classroom"). These interventions have the potential to reduce the social and economic drivers of HIV risk, improve utilization of prevention technologies and improve adherence to ART for adolescent populations in the hyper-endemic settings of Southern and Eastern Africa. Studies show that the integration of social and economic interventions has high acceptability and reach and that it holds powerful potential for improved HIV, health and development outcomes. CONCLUSIONS: Social protection is a largely untapped means of reducing HIV-risk behaviours and increasing uptake of and adherence to biomedical prevention and treatment technologies. There is now sufficient evidence to include social protection programming as a key strategy not only to mitigate the negative impacts of the HIV epidemic among families, but also to contribute to HIV prevention among adolescents and potentially to remove social and economic barriers to accessing treatment. We urge a further research and programming agenda: to actively combine programmes that increase availability of biomedical solutions with social protection policies that can boost their utilization.

Measurements of protein sequence-structure correlations.

Correlations between protein structures and amino acid sequences are widely used for protein structure prediction. For example, secondary structure predictors generally use correlations between a secondary structure sequence and corresponding primary structure sequence, whereas threading algorithms and similar tertiary structure predictors typically incorporate interresidue contact potentials. To investigate the relative importance of these sequence-structure interactions, we measured the mutual information among the primary structure, secondary structure and side-chain surface exposure, both for adjacent residues along the amino acid sequence and for tertiary structure contacts between residues distantly separated along the backbone. We found that local interactions along the amino acid chain are far more important than non-local contacts and that correlations between proximate amino acids are essentially uninformative. This suggests that knowledge-based contact potentials may be less important for structure predication than is generally believed.

The representation of social facial touch in rat barrel cortex.

Controlled presentation of stimuli to anesthetized [1] or awake [2] animals suggested that neurons in sensory cortices respond to elementary features [3, 4], but we know little about neuronal responses evoked by social interactions. Here we investigate processing in the barrel cortex of rats engaging in social facial touch [5, 6]. Sensory stimulation by conspecifics differs from classic whisker stimuli such as deflections, contact poles [7, 8], or textures [9, 10]. A large fraction of barrel cortex neurons responded to facial touch. Social touch responses peaked when animals aligned their faces and contacted each other by multiple whiskers with small, irregular whisker movements. Object touch was associated with larger, more regular whisker movements, and object responses were weaker than social responses. Whisker trimming abolished responses. During social touch, neurons in males increased their firing on average by 44%, while neurons in females increased their firing by only 19%. In females, socially evoked and ongoing firing rates were more than 1.5-fold higher in nonestrus than in estrus. Barrel cortex represented socially different contacts by distinct firing rates, and the variation of activity with sex and sexual status could contribute to the generation of gender-specific neural constructs of conspecifics.

Colchicine-induced degeneration of the micronucleus during conjugation in Tetrahymena.

One of the most dramatic examples of nuclear morphogenesis occurs during conjugation in Tetrahymena when the micronucleus elongates to a size longer than the cell itself. After contraction to a spherical shape, the nucleus moves directly to chromosome separation in the first meiotic division. Here we investigate the consequences of interrupting the elongation process. Colchicine, a microtubule inhibitor, caused retraction of elongated structures. With time, cells began to lose their micronuclei, and by five hours more than half of the paired cells had at least one cell missing a micronucleus. After reversing the colchicine block, existing micronuclei did not undergo elongation again, nor did meiosis occur. These observations indicate that micronuclear elongation is critical to subsequent meiotic division. Further, nuclear elimination occurs, which could be due to meiotic failure or possibly a problem downstream from meiosis. An analysis of the process of colchicine-induced micronuclear degeneration indicated that it was regulated by a caspase-dependent mechanism, characteristic of apoptosis, and then resorbed by a lysosome-dependent autophagic mechanism. Amicronucleate cells failed to grow when returned to nutrient medium, likely because of a lesion in the post-conjugation reconstruction of a functioning oral apparatus. The ease by which a large number of nuclei are induced to "self-destruct" may make this system useful in investigating the link between colchicine treatment and nuclear death in Tetrahymena, and in investigating how nuclear death could be regulated in living cells more generally. Finally, we note that this phenomenon might relate to the evolution of amicronucleate species of Tetrahymena.

Social facial touch in rats.

We know much about how rats use their whiskers to discriminate simple tactile properties, but little about how they are used in natural settings. Here we studied whisker motion during social interactions between rats in order to gain a better understanding of natural whisker use in this model system for sensorimotor integration. In the first set of experiments, an intruder was placed in a second rat's home cage. Anogenital sniffing immediately ensued; later in the trial, facial interactions occurred at least as frequently. Whereas much previous work has focused on the importance of anogenital sniffing during social interactions, these facial interactions were accompanied by some of the most intense whisker behaviors described to date. Whisker trimming increased biting but reduced boxing. In addition, whiskers were more protracted and whisking amplitude was larger in aggressive than in nonaggressive interactions. In a second set of experiments, rats interacted facially across a gap. As rats approached each other, whisking amplitude decreased and whiskers were more protracted. Whisker trimming disrupted facial alignment and reduced the frequency of interactions, indicating that whisker use, and possibly whisker protraction, is important for rats to orient themselves with respect to one another. We also found that females whisked with smaller amplitude when interacting with males than with females, and that they held their whiskers less protracted than males. The natural whisker use described here should further our understanding of this important somatosensory system during social interactions.

Psychometric curve and behavioral strategies for whisker-based texture discrimination in rats.

The rodent whisker system is a major model for understanding neural mechanisms for tactile sensation of surface texture (roughness). Rats discriminate surface texture using the whiskers, and several theories exist for how texture information is physically sensed by the long, moveable macrovibrissae and encoded in spiking of neurons in somatosensory cortex. However, evaluating these theories requires a psychometric curve for texture discrimination, which is lacking. Here we trained rats to discriminate rough vs. fine sandpapers and grooved vs. smooth surfaces. Rats intermixed trials at macrovibrissa contact distance (nose >2 mm from surface) with trials at shorter distance (nose <2 mm from surface). Macrovibrissae were required for distant contact trials, while microvibrissae and non-whisker tactile cues were used for short distance trials. A psychometric curve was measured for macrovibrissa-based sandpaper texture discrimination. Rats discriminated rough P150 from smoother P180, P280, and P400 sandpaper (100, 82, 52, and 35 µm mean grit size, respectively). Use of olfactory, visual, and auditory cues was ruled out. This is the highest reported resolution for rodent texture discrimination, and constrains models of neural coding of texture information.

The neurobiology of Etruscan shrew active touch.

The Etruscan shrew, Suncus etruscus, is not only the smallest terrestrial mammal, but also one of the fastest and most tactile hunters described to date. The shrew's skeletal muscle consists entirely of fast-twitch types and lacks slow fibres. Etruscan shrews detect, overwhelm, and kill insect prey in large numbers in darkness. The cricket prey is exquisitely mechanosensitive and fast-moving, and is as big as the shrew itself. Experiments with prey replica show that shape cues are both necessary and sufficient for evoking attacks. Shrew attacks are whisker guided by motion- and size-invariant Gestalt-like prey representations. Shrews often attack their prey prior to any signs of evasive manoeuvres. Shrews whisk at frequencies of approximately 14 Hz and can react with latencies as short as 25-30 ms to prey movement. The speed of attacks suggests that shrews identify and classify prey with a single touch. Large parts of the shrew's brain respond to vibrissal touch, which is represented in at least four cortical areas comprising collectively about a third of the cortical volume. Etruscan shrews can enter a torpid state and reduce their body temperature; we observed that cortical response latencies become two to three times longer when body temperature drops from 36°C to 24°C, suggesting that endothermy contributes to the animal's high-speed sensorimotor performance. We argue that small size, high-speed behaviour and extreme dependence on touch are not coincidental, but reflect an evolutionary strategy, in which the metabolic costs of small body size are outweighed by the advantages of being a short-range high-speed touch and kill predator.

Active touch during shrew prey capture.

Although somatosensation in multiple whisker systems has been studied in considerable detail, relatively little information is available regarding whisker usage and movement patterns during natural behaviors. The Etruscan shrew, one of the smallest mammals, relies heavily on its whisker system to detect and kill its highly mobile insect prey. Here, we tracked whisker and body motion during prey capture. We found that shrews made periodic whisker movements (whisking) with frequencies ranging from 12 to 17 Hz. We compared shrew and rat whisking and found that shrew whisking was smaller amplitude and higher frequency than rat whisking, but that the shrew and rat whisking cycle were similar in that the velocity was higher during retraction than protraction. We were able to identify four phases during the shrew hunting behavior: (i) an immobile phase often preceding hunting, (ii) a search phase upon the initiation of hunting, (iii) a contact phase defined by whisker-to-cricket contact, and (iv) an attack phase, characterized by a rapid head movement directed toward the cricket. During the searching phase, whisking was generally rhythmic and whiskers were protracted forward. After prey contact, whisking amplitude decreased and became more variable. The final strike was associated with an abrupt head movement toward the prey with high head acceleration. Prey capture proceeded extremely fast and we obtained evidence that shrews can initiate corrective maneuvers with a minimal latency <30 ms. While the shrew's rostrum is straight and elongated during most behaviors, we show for the first time that shrews bend their rostrum during the final strike and grip their prey with a parrot beak shaped snout.

Sparse and powerful cortical spikes.

Activity in cortical networks is heterogeneous, sparse and often precisely timed. The functional significance of sparseness and precise spike timing is debated, but our understanding of the developmental and synaptic mechanisms that shape neuronal discharge patterns has improved. Evidence for highly specialized, selective and abstract cortical response properties is accumulating. Singe-cell stimulation experiments demonstrate a high sensitivity of cortical networks to the action potentials of some, but not all, single neurons. It is unclear how this sensitivity of cortical networks to small perturbations comes about and whether it is a generic property of cortex. The unforeseen sensitivity to cortical spikes puts serious constraints on the nature of neural coding schemes.

Sparse temporal coding of elementary tactile features during active whisker sensation.

How the brain encodes relevant sensory stimuli in the context of active, natural sensation is not known. During active tactile sensation by rodents, whisker movement across surfaces generates complex whisker micro-motion, including discrete, transient slip-stick events, which carry information about surface properties. We simultaneously measured whisker motion and neural activity in somatosensory cortex (S1) in rats whisking across surfaces. Slip-stick motion events were prominently encoded by one or two low-probability, precisely timed spikes in S1 neurons, resulting in a probabilistically sparse ensemble code. Slips could be efficiently decoded from transient, correlated spiking (approximately 20-ms time scale) in small (approximately 100 neuron) populations. Slip responses contributed substantially to increased firing rate and transient firing synchrony on surfaces, and firing synchrony was an important cue for surface texture. Slips are thus a fundamental encoded tactile feature in natural whisker input streams and are represented by sparse, temporally precise, synchronous spiking in S1.

The conjugation junction of Tetrahymena: Its structure and development.

The conjugation junction of Tetrahymena has been examined by thin sections, freeze fracture preparations, and by scanning electron microscopy. The junction is formed where the anterior tips of the pairing cells attach to one another. The structure is essentially a large disk composed of two face-to-face plasma membranes separated by a gap of extracellular space measuring about 50 nm. Rows of intramembrane particles are present at the boundary between the junction and ordinary cell cortex. These particles form a ring around the junction. Subjacent to each membrane is a thick mottled layer of material. Pores form in the junction at sites of membrane fusion. Though wider than long, these structures are actually bridges of cytoplasm that connect the conjugating cells. Pores fall into certain size and shape classes, indicating that membrane fusion is highly controlled in this system. At the level of the cytoplasmic bridge the submembrane material is compact and electron-dense. Changes in the structure of the epiplasmic layer have been monitored as the normal cortex is modified during tip transformation and through formation of the mature conjugation junction. Evidence is provided that the submembrane layer plays a significant role in the regulation of pore formation. This cytoskeletal structure may also limit the extent of membrane fusion, thus controlling the size of the cytoplasmic channels.

Caspase-like activity is required for programmed nuclear elimination during conjugation in Tetrahymena.

During conjugation in the binucleate ciliate, Tetrahymena thermophila, the old macronucleus is eliminated as new macronuclei and micronuclei are ontogenetically derived from the zygote nucleus. The mechanism of programmed nuclear elimination in ciliates may be related to the mechanism of apoptosis in higher organisms since its chromatin undergoes major condensation, its DNA is digested into nucleosome-sized fragments, and it stains positively for TUNEL. The present study explores whether caspases are involved in programmed macronuclear degradation in Tetrahymena. We show here that caspase-like activity is detectable using two specific colorimetric substrates, and that the activity is reduced with specific caspase inhibitors. In addition, using the fluorigenic substrate PhiPhiLux, active caspase-like activity is detected in living cells, localized to cytoplasmic vesicles; activity is not detected in pre- or post-condensed macronuclei. Finally, three different inhibitors of caspase activity cause a block to macronuclear chromatin condensation and elimination. Therefore, a caspase-like enzyme activity is necessary for regulating macronuclear elimination in Tetrahymena. These data support the possibility that macronuclear elimination is related, evolutionarily, to regulated cell death in multicellular organisms.