Classification of chemically modified red blood cells in microflow using machine learning video analysis

We classify native and chemically modified red blood cells with an AI based video classifier. Using TensorFlow video analysis enables us to capture not only the morphology of the cell but also the trajectories of motion of individual red blood cells and their dynamics. We chemically modify cells in three different ways to model different pathological conditions and obtain classification accuracies for all three classification tasks of more than 90% between native and modified cells. Unlike standard cytometers that are based on immunophenotyping our microfluidic cytometer allows to rapidly categorize cells without any fluorescence labels simply by analysing the shape and flow of red blood cells.

Acoustic erythrocytometer for mechanically probing cell viscoelasticity

We demonstrate an acoustic device to mechanically probe a population of red blood cells at the single cell level. The device operates by exciting a surface acoustic wave in a microfluidic channel creating a stationary acoustic wave field of nodes and antinodes. Erythrocytes are attracted to the nodes and are deformed. Using a stepwise increasing and periodically oscillating acoustic field we study the static and dynamic deformation of individual red blood cells one by one. We quantify the deformation by the Taylor deformation index D and relaxation times τ₁ and τ₂ that reveal both the viscous and elastic properties of the cells. The precision of the measurement allows us to distinguish between individual cells in the suspension and provides a quantitative viscoelastic fingerprint of the blood sample at single cell resolution. The method overcomes limitations of other techniques that provide averaged values and has the potential for high-throughput.

Traveling surface acoustic wave (TSAW) microfluidic fluorescence activated cell sorter (μFACS)

We report a microfluidic fluorescence activated cell-sorting (μFACS) device that employs traveling surface acoustic waves (TSAW) to sort cells at rates comparable to conventional jet-in-air FACS machines, with high purity and viability. The device combines inertial flow focusing and sheath flow to align and evenly space cells, improving the sorting accuracy and screening rate. We sort with an interdigital transducer (IDT) whose tapered geometry allows precise positioning of the TSAW for optimal cell sorting. We sort three different cell lines at several kHz, at cell velocities exceeding one meter per second, while maintaining both sorting purity and cell viability at around 90% simultaneously.

Binary Colloidal Nanoparticle Concentration Gradients in a Centrifugal Field at High Concentration

Binary colloidal nanoparticles have been found to form different types of crystalline phases at varied radial positions in a centrifugal field by Chen et al. ( ACS Nano 2015, 9, 6944-50). The variety of binary phase behaviors resulted from the two different nanoparticle concentration gradients, but to date, the gradients can only be empirically controlled. For the first time, we are able to measure, fit, and simulate binary hard-sphere colloidal nanoparticle concentration gradients at high particle concentrations up to 30 vol %, which enables tailor-made gradients in a centrifugal field. By this means, a continuous range of binary particle concentration ratios can be accessed in one single experiment to obtain an extended phase diagram. By dispersing two differently sized silica nanoparticles labeled with two different fluorescence dyes in a refractive index matching solvent, we can use a multi-wavelength analytical ultracentrifuge (MWL-AUC) to measure the individual concentration gradient for each particle size in sedimentation-diffusion equilibrium. The influence of the remaining slight turbidity at high concentration can be corrected using the MWL spectra from the AUC data. We also show that the experimental concentration gradients can be fitted using a noninteracting nonideal sedimentation model. By using these fitted parameters, we are able to simulate nanoparticle concentration gradients, which agreed with the subsequent experiments at a high concentration of 10 vol % and thus allowed for the simulation of binary concentration gradients of hard-sphere nanoparticles in preparative ultracentrifuges (PUCs). Finally we demonstrated that by simulating the concentration gradients in PUCs, a continuous and extended binary nanoparticle phase diagram can be obtained by simply studying the structure evolution along the centrifugal field for one single sample instead of a large number of experiments with discrete compositions as in conventional studies.

Bimorph material/structure designs for high sensitivity flexible surface acoustic wave temperature sensors

A fundamental challenge for surface acoustic wave (SAW) temperature sensors is the detection of small temperature changes on non-planar, often curved, surfaces. In this work, we present a new design methodology for SAW devices based on flexible substrate and bimorph material/structures, which can maximize the temperature coefficient of frequency (TCF). We performed finite element analysis simulations and obtained theoretical TCF values for SAW sensors made of ZnO thin films (~5 μm thick) coated aluminum (Al) foil and Al plate substrates with thicknesses varied from 1 to 1600 μm. Based on the simulation results, SAW devices with selected Al foil or plate thicknesses were fabricated. The experimentally measured TCF values were in excellent agreements with the simulation results. A normalized wavelength parameter (e.g., the ratio between wavelength and sample thickness, λ/h) was applied to successfully describe changes in the TCF values, and the TCF readings of the ZnO/Al SAW devices showed dramatic increases when the normalized wavelength λ/h was larger than 1. Using this design approach, we obtained the highest reported TCF value of −760 ppm/K for a SAW device made of ZnO thin film coated on Al foils (50 μm thick), thereby enabling low cost temperature sensor applications to be realized on flexible substrates.

Enhanced surface acoustic wave cell sorting by 3D microfluidic-chip design

We demonstrate an acoustic wave driven microfluidic cell sorter that combines advantages of multilayer device fabrication with planar surface acoustic wave excitation. We harness the strong vertical component of the refracted acoustic wave to enhance cell actuation by using an asymmetric flow field to increase cell deflection. Precise control of the 3-dimensional flow is realized by topographical structures implemented on the top of the microchannel. We experimentally quantify the effect of the structure dimensions and acoustic parameter. The design attains cell sorting rates and purities approaching those of state of the art fluorescence-activated cell sorters with all the advantages of microfluidic cell sorting.

Visualization of Surface Acoustic Waves in Thin Liquid Films

We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

[Medical operations at the 2010 love parade in Duisburg]

On 24 July 2010 the love parade, a large scale open air concert was held in the city of Duisburg to which more than 500,000 guests were expected. During the course of the early evening a major tragic incident occurred in which 21 people were crushed to death and several hundred others were injured. In this article the preparation of the emergency and rescue services prior to the event is described and their operations entailing more than 1,600 staff members from all over Germany are illustrated. The article focuses on the mass casualty incident which took place in the tunnel in the early evening of that day.

Optical imaging of concealed brain activity using a gold mirror in honeybees

Brain activity is inherently combinatorial and three-dimensional. Optical imaging techniques offer a suitable opportunity to record many activity foci simultaneously, but under conventional microscopy conditions, optical access is generally limited to the frontal part of the brain. Thus, even for cases in which optical recordings have delivered substantial data, our knowledge of deeper layers is deficient. Using the honeybee olfactory system as a test system, we report that by using a gold-sputtered cover slip as a minute mirror, it is possible to optically access and record from otherwise inaccessible brain areas. In insects, the first brain area to code for odors is the antennal lobe (comparable to the vertebrate olfactory bulb). Several previous studies have characterized glomerular odor response patterns of the frontal view, readily accessible when the head capsule of the bee is opened. However, until now, the back and the sides of the antennal lobe have remained utterly unexplored. This is particularly relevant because in the honeybee these two views coincide with two separate olfactory subsystems, related to two axonal tracts of second-order neurons: the lAPT and the mAPT. Combining wide-field microscopy, calcium imaging, and a minute mirror, we report the first glomerular odor responses from the side of the honeybee antennal lobe.

Dynamics of red blood cells and vesicles in microchannels of oscillating width

We have studied the dynamics of red blood cells and fluid lipid vesicles in hydrodynamic flow fields created by microchannels with periodically varying channel width. For red blood cells we find a transition from a regime with oscillating tilt angle and fixed shape to a regime with oscillating shape with increasing flow velocity. We have determined the crossover to occur at a critical ratio L(y)/v(m) ≈ 2.2 × 10⁻³ s with channel width L(y) and red blood cell velocity v(m). These oscillations are superposed by shape transitions from a discocyte to a slipper shape at low velocities and a slipper to parachute transition at high flow velocities.

[The social city and the elderly]

Despite the importance of the idea of accommodation and the elderly, this group is currently not the main focus of the "Socially Integrative City" (Soziale Stadt) program. From the perspective of this important target group, housing and the living environment, local supply, mobility, health promotion, and the integration of immigrants are important fields of action that should be further considered. This requires, above all, involving the elderly in planning and implementation of projects and measures for integrated neighborhood development by intense activation and participation. In addition, local partnerships between government, social and health services, housing associations, business and local initiatives (clubs, self-help organizations) are prerequisite for successful development neighborhood.

Surface acoustic wave actuated cell sorting (SAWACS)

We describe a novel microfluidic cell sorter which operates in continuous flow at high sorting rates. The device is based on a surface acoustic wave cell-sorting scheme and combines many advantages of fluorescence activated cell sorting (FACS) and fluorescence activated droplet sorting (FADS) in microfluidic channels. It is fully integrated on a PDMS device, and allows fast electronic control of cell diversion. We direct cells by acoustic streaming excited by a surface acoustic wave which deflects the fluid independently of the contrast in material properties of deflected objects and the continuous phase; thus the device underlying principle works without additional enhancement of the sorting by prior labelling of the cells with responsive markers such as magnetic or polarizable beads. Single cells are sorted directly from bulk media at rates as fast as several kHz without prior encapsulation into liquid droplet compartments as in traditional FACS. We have successfully directed HaCaT cells (human keratinocytes), fibroblasts from mice and MV3 melanoma cells. The low shear forces of this sorting method ensure that cells survive after sorting.

Analyzing the content of outcome measures in clinical trials on irritable bowel syndrome using the international classification of functioning, disability and health as a reference

BACKGROUND

Patients with irritable bowel syndrome (IBS) report a significant impact of their symptoms on functional health. In outcome assessment of clinical studies on IBS, however, functional aspects other than gastrointestinal symptoms seem to be disregarded to a great extent.

AIM

To analyze the content of outcome measures used in clinical IBS trials.

METHODS

A systematic review was performed in terms of a quantitative content analysis using the International Classification of Functioning, Disability and Health (ICF) as a coding scheme. Outcome measures were selected from all randomized controlled trials on IBS published in PubMed from the beginning to April 2002. From the outcome measures pre-specified text passages, so-called coding units, were extracted and linked to the ICF. A coding unit had to describe a single health aspect or an internal or external factor with an impact on health. If the outcome measure was a test the goal of the test was semantically implicated. Only second-level ICF categories contained in the outcome assessment of at least 10 % of the studies were considered. All steps of the review were performed by three independent raters.

RESULTS

99 studies were included. Single items were used as outcome measures in 88, clinical and paraclinical tests in 42 and questionnaires in 24 studies. Ninety percent of the coding units (n = 2271) could be linked to the ICF. ICF categories describing gastrointestinal symptoms were considered in the outcome assessment of 37 to 85 studies depending on the type of content compared to extra-gastrointestinal symptoms in 10 to 22 studies. Health information of ICF components other than "body functions" was scarcely included. Clear secular trends for individual ICF categories could not be found. Only a single IBS-specific questionnaire considered health information other than gastrointestinal symptoms.

DISCUSSION AND CONCLUSION

Outcome assessment of clinical IBS studies is mainly based on gastrointestinal symptoms. The assessment of other health aspects like comorbid psychological symptoms or social consequences of the disease seems to be similarly important and should be considered in future trials. This would also facilitate the understanding of IBS as a biopsychosocial health condition, both in matters of aetiology and consequences.

Medication errors in United States hospitals

This study evaluated hospital demographics, staffing, pharmacy variables, health care outcomes measures (severity of illness-adjusted mortality rates, drug costs, total cost of care, and length of stay) and medication errors. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 mortality data from the Health Care Financing Administration. Simple statistical tests and a severity of illness-adjusted multiple regression analysis were employed. The study population consisted of 1116 hospitals that reported information on medication errors and 913 hospitals that reported information on medication errors that adversely affected patient care outcomes. We evaluated factors associated with the 430,586 medication errors and 17,338 medication errors that adversely affected patient care outcomes. Medication errors occurred in 5.07% of the patients admitted each year to these hospitals. Each hospital experienced a medication error every 22.7 hours (every 19.73 admissions). Medication errors that adversely affected patient care outcomes occurred in 0.25% of all patients admitted to these hospitals/year. Each hospital experienced a medication error that adversely affected patient care outcomes every 19.23 days (or every 401 admissions). The following factors were associated with increased medication errors/occupied bed/year: lack of pharmacy teaching affiliation (slope = 0.8875, p=0.0416), centralized pharmacists (slope = 1.0942, p=0.0001), number of registered nurses/occupied bed (slope = 1.624, p=0.032), number of registered pharmacists/occupied bed (slope = 25.0573, p=0.0001), hospital mortality rate (slope = 2.8017, p=0.0192), and total cost of care/occupied bed/year (slope = 0.01432, p=0.0091). Factors associated with decreased medication errors were location in the Mid-Atlantic census region (slope = -1.5182, p=0.03), affiliation with a pharmacy teaching program (slope = -1.0252, p=0.0349), decentralized pharmacists (slope = -0.9843, p=0.0037), and number of medical residents/occupied bed (slope = -1.478, p=0.0014). There was a 45% decrease in medication errors (1.81-fold decrease) in hospitals that had decentralized pharmacists, compared with hospitals that had centralized pharmacists. In addition, there was a 94% decrease in medication errors that adversely affected patient care outcomes (16.88-fold decrease) in hospitals that had decentralized pharmacists compared with hospitals that had only centralized pharmacists. Based on previous field studies and our findings in 1116 hospitals, it appears that one of the most effective ways to prevent or reduce medication errors is to decentralize pharmacists to patient care areas. The results of this study should help hospitals reduce the number of medication errors that occur each year.

Interrelationships among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals: summary and recommendations for clinical pharmacy services and staffing

We evaluated interrelationships and associations among mortality rates, drug costs, total cost of care, and length of stay in United States hospitals. Relationships between these variables and the presence of clinical pharmacy services and pharmacy staffing also were explored. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field, the 1992 National Clinical Pharmacy Services database, and 1992 Health Care Finance Administration mortality data. A severity of illness-adjusted multiple regression analysis was employed to determine relationships and associations. Study populations ranged from 934-1029 hospitals (all hospitals for which variables could be matched). The only pharmacy variable associated with positive outcomes with all four health care outcome measures was the number of clinical pharmacists/occupied bed. That figure tended to have the greatest association (slope) with reductions in mortality rate, drug costs, and length of stay. As clinical pharmacist staffing levels increased from the tenth percentile (0.34/100 occupied beds) to the ninetieth percentile (3.23/100 occupied beds), hospital deaths declined from 113/1000 to 64/1000 admissions (43% decline). This resulted in a reduction of 395 deaths/hospital/year when clinical pharmacist staffing went from the tenth to the ninetieth percentile. This translated into a reduction of 1.09 deaths/day/hospital having clinical pharmacy staffing between these staffing levels, or 320 dollars of pharmacist salary cost/death averted. Three hospital pharmacy variables were associated with reduced length of stay in 1024 hospitals: drug protocol management (slope -1.30, p=0.008), pharmacist participation on medical rounds (slope -1.71, p<0.001), and number of clinical pharmacists/occupied bed (slope -26.59, p<0.001). As drug costs/occupied bed/year increased, severity of illness-adjusted mortality rates decreased (slope -38609852, R(2) 8.2%, p<0.0001). As the total cost of care/occupied bed/year increased, those same mortality rates decreased (slope -5846720642, R(2) 14.9%, p<0.0001). Seventeen clinical pharmacy services were associated with improvements in the four variables.

Ten years experience with lung and heart-lung transplantation in primary and secondary pulmonary hypertension

OBJECTIVE

Patients with primary pulmonary hypertension (PPHT) have a worse natural outcome compared with those with secondary pulmonary hypertension in Eisenmenger's syndrome (ES) and chronic pulmonary embolism (CPE). Lung transplantation (SLTx, DLTx, HLTx) still remains the only therapeutical option for patients with this type of endstage lung disease.

METHODS

From 1988 to 1998, 63 patients underwent lung transplantation for PPHT (n=29, 9 m, 20 f, 2 SLTx, 14 DLTx, 13 HLTx), ES (n=29, 13 m, 16 f, 2 SLTx, 3 DLTx, 24 HLTx) or CPE (n=5, 2 m, 3 f, 1 SLTx, 2 DLTx, 2 HLTx). Groups were comparable for NYHA functional class, preoperative pulmonary arterial pressure, recipient and donor age, ischemic time, necessity and duration of cardiopulmonary bypass and cross-match.

RESULTS

The 1-, 3- and 5-year survival was 52, 40 and 35% for the PPHT-group, 83, 78 and 74% for the ES-group and 80, 60 and 60% for the CPE-group, respectively (P=0.026, P=0.033, P=0.082 for 1-, 3- and 5-year survival). Patients following DLTx showed a lower 1-year survival rate as compared with patients after HLTx both in PPHT patients (36 vs. 62%, P=0.091) and in ES patients (67 vs. 83%, P=0.213). The incidence of bronchiolitis obliterans syndrome was 29% at 1 year and 45% at 3 years for the PPHT-group vs. 17 and 65% for the ES-group (n. s. in between groups). Excluding postoperative ventilation time (PPHT-group: 26.8+/-24.0 days vs. ES-group: 16.1+/-30.8 days, P=0. 011) and a higher incidence of infectious causes of death (PPHT-group n=8 vs. ES-group n=1, P=0.017) groups were comparable with regard to their postoperative courses.

CONCLUSIONS

It is concluded, that predominantly the underlying primary disease influences graft survival after lung transplantation in patients with pulmonary hypertension compared with all other patient and procedure dependent factors. Lung transplantation in patients with PPHT requires further investigations to achieve results comparable with other indications.

Long-term efficacy of radon spa therapy in rheumatoid arthritis--a randomized, sham-controlled study and follow-up

OBJECTIVE

To quantify the efficacy of a series of baths containing natural radon and carbon dioxide (1.3 kBq/l, 1.6 g carbon dioxide/l on average) versus artificial carbon dioxide baths alone in patients with rheumatoid arthritis.

SUBJECTS

Sixty patients participating in an in-patient rehabilitation programme including a series of 15 baths were randomly assigned to two groups.

DESIGN

Pain intensity (100 mm visual analogue scale) and functional restrictions [Keitel functional test, Arthritis Impact Measurement Scales (AIMS questionnaire)] were measured at baseline, after completion of treatment and 3 and 6 months thereafter. To investigate whether the overall value of the outcomes was the same in both groups, the overall mean was analysed by Student's t-test for independent samples.

RESULTS

The two groups showed a similar baseline situation. After completion of treatment, relevant clinical improvements were observed in both groups, with no notable group differences. However, the follow-up revealed sustained effects in the radon arm, and a return to baseline levels in the sham arm. After 6 months, marked between-group differences were found for both end-points (pain intensity: -16.9%, 95% confidence interval -27.6 to -6.2%; AIMS score: 0.57, 95% confidence interval 0.16 to 0.98). The between-group differences were statistically significant for both overall means (pain intensity, P: = 0.04; AIMS, P: = 0.01).

CONCLUSION

Marked short-term improvements in both groups at the end of treatment may have masked potential specific therapeutic effects of radon baths. However, after 6 months of follow-up the effects were lasting only in patients of the radon arm. This suggests that this component of the rehabilitative intervention can induce beneficial long-term effects.

Clinical pharmacy services, pharmacy staffing, and the total cost of care in United States hospitals

This study evaluated direct relationships and associations among clinical pharmacy services, pharmacist staffing, and total cost of care in United States hospitals. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field and the 1992 National Clinical Pharmacy Services Database. A multiple regression analysis, controlling for severity of illness, was employed to determine the relationships and associations. The study population consisted of 1016 hospitals. Six clinical pharmacy services were associated with lower total cost of care: drug use evaluation (p=0.001), drug information (p=0.003), adverse drug reaction monitoring (p=0.008), drug protocol management (p=0.001), medical rounds participation (p=0.0001), and admission drug histories (p=0.017). Two services were associated with higher total cost of care: total parenteral nutrition (TPN) team participation (p=0.001) and clinical research (p=0.0001). Total costs of care/hospital/year were lower when any of six clinical pharmacy services were present: drug use evaluation $1,119,810.18 (total $1,005,589,541.64 for the 898 hospitals offering the service), drug information $5,226,128.22 (total $1,212,461,747.04 for the 232 hospitals offering the service), adverse drug reporting monitoring $1,610,841.02 (total $1,101,815, 257.68 for the 684 hospitals offering the service), drug protocol management $1,729,608.41 (total $614,010,985.55 for the 355 hospitals offering the service), medical rounds participation $7,979,720.45 (total $1,212,917,508.41 for the 152 hospitals offering the service), and admission drug histories $6,964,145.17 (total $208,924,355.10 for the 30 hospitals offering the service). Clinical research $9,558,788.01 (total $1,013,231,529.06 for the 106 hospitals offering the service) and TPN team participation $3,211,355.12 (total $1,027,633,638.43 for the 320 hospitals offering the service) were associated with higher total costs of care. As staffing increased for hospital pharmacy administrators (p=0.0001) and clinical pharmacists (p=0.007), total cost of care decreased. As staffing increased for dispensing pharmacists, total cost of care increased (p=0.006). Based on this total cost of care model, optimal hospital pharmacy administrator staffing was 2.01/100 occupied beds. Staffing for dispensing pharmacists should be as low as possible, and definitely fewer than 5.11/100 occupied beds. Staffing for clinical pharmacists should be as high as possible, but definitely more than 1.11/100 occupied beds. The results of this study suggest that increased staffing levels of clinical pharmacists and pharmacy administrators, as well as some clinical pharmacy services, were associated with reduced total cost of care in United States hospitals.

Clinical pharmacy services, pharmacist staffing, and drug costs in United States hospitals

We evaluated direct relationships and associations among clinical pharmacy services, pharmacist staffing, and drug costs in United States hospitals. A database was constructed from the 1992 American Hospital Association's Abridged Guide to the Health Care Field and the 1992 National Clinical Pharmacy Services database. Multiple regression analysis, controlling for severity of illness, was employed to determine the associations. The study population consisted of 934 hospitals. Four clinical pharmacy services were associated with lower drug costs: in-service education, $77,879.19+/-$56,203.42 (a total of $48,518,735.37 for the 623 hospitals offering this service, p=0.016); drug information, $430,579.84+/-$299,232.76 ($90,852,346.24 for the 211 hospitals offering this service, p=0.015); drug protocol management, $137,333.67+/-$98,617.83 ($45,045,443.76 for the 328 hospitals offering this service, p=0.049); and admission drug histories, $213,388.21+/-$201,537.85 ($5,548,093.46 for the 26 hospitals offering this service, p=0.011). As staffing increased for hospital pharmacy administrators (p<0.0001), dispensing pharmacists (p<0.0001), and pharmacy technicians (p<0.0001), drug costs increased. As staffing increased for clinical pharmacists, drug costs decreased (p=0.018). The results of this study show that increased staff levels of clinical pharmacists and some clinical pharmacy services are associated with reduced hospital drug costs.

Clinical pharmacy services and hospital mortality rates

We evaluated the associations between clinical pharmacy services and mortality rates in 1029 United States hospitals. A data base was constructed from Medicare mortality rates from the Health Care Financing Administration and the National Clinical Pharmacy Services data base. A multivariate regression analysis, controlling for severity of illness, was employed to determine the associations. Four clinical pharmacy services were associated with lower mortality rates: clinical research (p<0.0001), drug information (p=0.043), drug admission histories (p=0.005), and participation on a cardiopulmonary resuscitation (CPR) team (p=0.039). The actual number of deaths (lower) associated with the presence of these four services were clinical research 21,125 deaths in 108 hospitals, drug information 10,463 deaths in 237 hospitals, drug admission histories 3843 deaths in 30 hospitals, and CPR team participation 5047 deaths in 282 hospitals. This is the first study to indicate that both centrally based and patient-specific clinical pharmacy services are associated with reduced hospital mortality rates. This suggests that these services save a significant number of lives in our nation's hospitals.

Akt-dependent potentiation of L channels by insulin-like growth factor-1 is required for neuronal survival

The insulin-like growth factor-1 (IGF-1)/receptor tyrosine kinase recently has been shown to mediate neuronal survival and potentiate the activity of specific calcium channel subtypes; survival requires Akt, a serine/threonine kinase. We demonstrate here that Akt mediates the IGF-1-induced potentiation of L channel currents, but not that of N channels. Transient expression of wild-type, dominant-negative, and constitutively active forms of Akt in cerebellar granule neurons causes, respectively, no change in IGF-1/L channel potentiation, complete inhibition of potentiation, and a dramatic increase in basal L currents accompanied by the loss of ability to induce further increases. In no case is the IGF-1 potentiation of N currents affected. We additionally find that IGF-1 partially mediates granule neuron survival via L channel activity and that Akt-dependent L channel modulation is a necessary component. Interestingly, very brief exposure (1 min) to IGF-1 triggers nearly complete survival and requires L channel activity. These results strongly suggest that neuronal receptor tyrosine kinases can control long-term calcium-dependent processes via the rapid control of voltage-sensitive channels.

Health care professional staffing, hospital characteristics, and hospital mortality rates

To evaluate associations among hospital characteristics, staffing levels of health care professionals, and mortality rates in 3763 United States hospitals, a data base was constructed from the American Hospital Association's Abridged Guide to the Health Care Field and hospital Medicare mortality rates from the Health Care Financing Administration. A multivariate regression analysis controlling for severity of illness was employed to determine the associations. Hospital characteristics associated with lower mortality were occupancy rate and private nonprofit and private for-profit ownership. Mortality rates decreased as staffing level per occupied bed increased for medical residents, registered nurses, registered pharmacists, medical technologists, and total hospital personnel. Mortality rates increased as staffing level per occupied bed increased for hospital administrators and licensed practical-vocational nurses. To our knowledge, this is the first study to show that pharmacists were associated with lower mortality rates.