Imaging GPCR internalization using near-infrared Nebraska red-based reagents

Internalization of G protein-coupled receptor (GPCRs) represents a nearly universal pathway for receptor downregulation. Imaging this process provides a means for the identification of pharmaceutical agents as well as potential ligands for orphan receptors. However, there is a need for the further development of near-infrared (NIR) probes capable of monitoring internalization in order to enable multiplexing with existing green fluorescent GPCR activity assays. Our laboratory has recently described a series of near-infrared (NIR) fluorophores in which a phosphinate functionality is inserted at the bridging position of the xanthene scaffold. These fluorophores, termed Nebraska Red (NR) dyes, provide attractive reagents for imaging protein localization. Herein, we disclose the development of NR-based HaloTag ligands for imaging membrane proteins on living cells. These new probes are utilized to image membrane pools of the human orexin type 2 receptor, an established target for the treatment of insomnia. We demonstrate the ability of fetal bovine serum (FBS) to noncovalently associate with a spirolactonized NR probe, enabling no-wash imaging with a 45-fold enhancement of fluorescence. Furthermore, we characterize the utility of NR-based HaloTag ligands for real-time monitoring of receptor internalization upon agonist stimulation. These new reagents enable potential multiplexing with existing GPCR activity assays in order to identify new modulators of GPCR activity as well as ligands for orphan receptors.

A Panel of Protein Kinase Chemosensors Distinguishes Different Types of Fatty Liver Disease

The worldwide incidence of fatty liver disease continues to rise, which may account for concurrent increases in the frequencies of more aggressive liver ailments. Given the existence of histologically identical fatty liver disease subtypes, there is a critical need for the identification of methods that can classify disease and potentially predict progression. Herein, we show that a panel of protein kinase chemosensors can distinguish fatty liver disease subtypes. These direct activity measurements highlight distinct differences between histologically identical fatty liver diseases arising from diets rich in fat versus alcohol and identify a previously unreported decrease in p38α activity associated with a high-fat diet. In addition, we have profiled kinase activities in both benign (diet-induced) and progressive (STAM) disease models. These experiments provide temporal insights into kinase activity during disease development and progression. Altogether, this work provides the basis for the future development of clinical diagnostics and potential treatment strategies.

Design and synthesis of fluorescent activity probes for protein phosphatases

Protein phosphatases act in concert with protein kinases to regulate and maintain the phosphoproteome. However, the catalog of chemical tools to directly monitor the enzymatic activity of phosphatases has lagged behind their kinase counterparts. In this chapter, we provide protocols for repurposing the phosphorylation-sensitive sulfonamido-oxine fluorophore known as Sox to afford direct activity probes for phosphatases. With validated activity probes in-hand, inhibitor screens can be conducted with recombinant enzyme and the role of phosphatases in cell signaling can be investigated in unfractionated cell lysates.

Chemoselective Alteration of Fluorophore Scaffolds as a Strategy for the Development of Ratiometric Chemodosimeters

Ratiometric sensors generally couple binding events or chemical reactions at a distal site to changes in the fluorescence of a core fluorophore scaffold. However, such approaches are often hindered by spectral overlap of the product and reactant species. We provide a strategy to design ratiometric sensors that display dramatic spectral shifts by leveraging the chemoselective reactivity of novel functional groups inserted within fluorophore scaffolds. As a proof-of-principle, fluorophores containing a borinate (RF620 ) or silanediol (SiOH2R) functionality at the bridging position of the xanthene ring system are developed as endogenous H2 O2 sensors. Both these fluorophores display far-red to near-infrared excitation and emission prior to reaction. Upon oxidation by H2 O2 both sensors are chemically converted to tetramethylrhodamine, producing significant (≥66 nm) blue-shifts in excitation and emission maxima. This work provides a new concept for the development of ratiometric probes.

Quantification of Cell Signaling Networks Using Kinase Activity Chemosensors

The ability to directly determine endogenous kinase activity in tissue homogenates provides valuable insights into signaling aberrations that underlie disease phenotypes. When activity data is collected across a panel of kinases, a unique "signaling fingerprint" is generated that allows for discrimination between diseased and normal tissue. Here we describe the use of peptide-based kinase activity sensors to fingerprint the signaling changes associated with disease states. This approach leverages the phosphorylation-sensitive sulfonamido-oxine (Sox) fluorophore to provide a direct readout of kinase enzymatic activity in unfractionated tissue homogenates from animal models or clinical samples. To demonstrate the application of this technology, we focus on a rat model of nonalcoholic fatty liver disease (NAFLD). Sox-based activity probes allow for the rapid and straightforward analysis of changes in kinase enzymatic activity associated with disease states, providing leads for further investigation using traditional biochemical approaches.

Temporal Analysis of PP2A Phosphatase Activity During Insulin Stimulation Using a Direct Activity Probe

Protein serine/threonine phosphatases (PSPs) are ubiquitously expressed in mammalian cells. In particular, PP2A accounts for up to 1% of the total protein within cells. Despite clear evidence for the role of PP2A in cellular signaling, there is a lack of information concerning the magnitude and temporal dynamics of PP2A catalytic activity during insulin stimulation. Herein, we describe the development of a direct, fluorescent activity probe capable of reporting on global changes in PP2A enzymatic activity in unfractionated cell lysates. Utilizing this new probe, we profiled the magnitude as well as temporal dynamics of PP2A activity during insulin stimulation of liver hepatocytes. These results provide direct evidence for the rapid response of PP2A catalytic activity to extracellular stimulation, as well as insight into the complex regulation of phosphorylation levels by opposing kinase and phosphatase activities within the cell. This study provides a new tool for investigating the chemical biology of PSPs.

Nebraska Red: a phosphinate-based near-infrared fluorophore scaffold for chemical biology applications

A series of novel phosphinate-based dyes displaying near-infrared fluorescence (NIR) are reported. These dyes exhibit remarkable photostability and brightness. The phosphinate functionality is leveraged as an additional reactive handle in order to tune cell permeability as well as provide a proof-of-principle for a self-reporting small molecule delivery vehicle.

Respiratory failure of two sp gastric bypass patients and subsequent rescue with extracorporeal membrane oxygenation

Severe obesity is a chronic condition that is difficult to treat through diet and exercise alone. Gastrointestinal surgery for obesity (bariatric surgery) alters the digestive process by either restrictive surgical alterations or malabsorptive operations. Some 10 - 20% of patients who have weight-loss surgery require follow-up operations to correct complications. Hypoxemia after gastric bypass surgery for morbid obesity, a reported complication, can occur as early as 24 h post surgery.

Two patients presented with severe hypoxia and were placed on veno-venous extracorporeal membrane oxygenation (ECMO). Patient No. 1 had an obstruction of the alimentary limb of the gastric bypass due to suture adhesions, and patient No. 2 had an incarcerated diaphragmatic hernia. While on ECMO, ventilation using a protective strategy (60% FiO2, pressure-controlled ventilation inspiratory pressure (PCV) IP 25-27, positive end-expiratory pressure (PEEP) 10-14, permissive hyper-capnia) was employed. An inflow cannula to the level of the right atrium served as arterial outflow from the circuit to the patient, while the femoral vein served as venous inflow to the ECMO circuit.

Although ECMO in adult respiratory failure is often used as the last resort due to serious associated adverse events, we report two patients with life-threatening complications from gastric bypass who were rescued, resuscitated to day 7, and uneventfully discharged from the hospital to home.

Interrogating Endogenous Protein Phosphatase Activity with Rationally Designed Chemosensors

We introduce a versatile approach for repurposing protein kinase chemosensors, containing the phosphorylation-sensitive sulfonamido-oxine fluorophore termed Sox, for the specific determination of endogenous protein phosphatase activity from whole cell lysates and tissue homogenates. As a demonstration of this approach, we design and evaluate a direct chemosensor for protein tyrosine phosphatase-1B (PTP1B), an established signaling node in human disease. The optimal sensor design is capable of detecting as little as 6 pM (12 pg) full-length recombinant PTP1B and is remarkably selective for PTP1B among a panel of highly homologous tyrosine phosphatases. Coupling this robust activity probe with the specificity of antibodies allowed for the temporal analysis of endogenous PTP1B activity dynamics in lysates generated from HepG2 cells after stimulation with insulin. Lastly, we leveraged this assay format to profile PTP1B activity perturbations in a rat model of nonalcoholic fatty liver disease (NAFLD), providing direct evidence for elevated PTP1B catalytic activity in this disease state. Given the modular nature of this assay, we anticipate that this approach will have broad utility in monitoring phosphatase activity dynamics in human disease states.

Design and evaluation of a real-time activity probe for focal adhesion kinase

Focal adhesion kinase (FAK) has been identified as a potential therapeutic target for the treatment of metastatic cancers. Herein we describe the design, synthesis and optimization of a direct activity sensor for FAK and its application to screening FAK inhibitors. We find that the position of the sensing moiety, a phosphorylation-sensitive sulfonamido-oxine fluorophore, can dramatically influence the performance of peptide sensors for FAK. Real-time fluorescence activity assays using an optimized sensor construct, termed FAKtide-S2, are highly reproducible (Z' = 0.91) and are capable of detecting as little as 1 nM recombinant FAK. Utilizing this robust assay format, we define conditions for the screening of FAK inhibitors and demonstrate the utility of this platform using a set of well-characterized small molecule kinase inhibitors. Additionally, we provide the selectivity profile of FAKtide-S2 among a panel of closely related enzymes, identifying conditions for selectively monitoring FAK activity in the presence of off-target enzymes. In the long term, the chemosensor platform described in this work can be used to identify novel FAK inhibitor scaffolds and potentially assess the efficacy of FAK inhibitors in disease models.

Economic evaluation of DNA ploidy analysis vs liquid-based cytology for cervical screening

Background:

DNA ploidy analysis involves automated quantification of chromosomal aneuploidy, a potential marker of progression toward cervical carcinoma. We evaluated the cost-effectiveness of this method for cervical screening, comparing five ploidy strategies (using different numbers of aneuploid cells as cut points) with liquid-based Papanicolaou smear and no screening.

Methods:

A state-transition Markov model simulated the natural history of HPV infection and possible progression into cervical neoplasia in a cohort of 12-year-old females. The analysis evaluated cost in 2012 US$ and effectiveness in quality-adjusted life-years (QALYs) from a health-system perspective throughout a lifetime horizon in the US setting. We calculated incremental cost-effectiveness ratios (ICERs) to determine the best strategy. The robustness of optimal choices was examined in deterministic and probabilistic sensitivity analyses.

Results:

In the base-case analysis, the ploidy 4 cell strategy was cost-effective, yielding an increase of 0.032 QALY and an ICER of $18 264/QALY compared to no screening. For most scenarios in the deterministic sensitivity analysis, the ploidy 4 cell strategy was the only cost-effective strategy. Cost-effectiveness acceptability curves showed that this strategy was more likely to be cost-effective than the Papanicolaou smear.

Conclusion:

Compared to the liquid-based Papanicolaou smear, screening with a DNA ploidy strategy appeared less costly and comparably effective.

Quantification of protein kinase enzymatic activity in unfractionated cell lysates using CSox-based sensors

Defining perturbations in protein kinase activity within biological samples can provide insight into disease mechanisms as well as potential targets for drug development. In this article, we present a method that utilizes a phosphorylation-sensitive amino acid, termed CSox, to afford kinase-selective biosensors capable of reporting on enzymatic activity directly in biological samples. These sensors produce an increase in fluorescence in response to phosphorylation of an amino acid residue adjacent to CSox. Probes can be designed for either serine/threonine or tyrosine kinases, and analysis can be performed using standard fluorescence equipment. The procedures provided herein represent our optimized protocols for the design, validation, and application of CSox-based protein kinase activity sensors.

Real-time data acquisition and alerts may reduce reaction time and improve perfusionist performance during cardiopulmonary bypass

Delayed perfusionist identification and reaction to abnormal clinical situations has been reported to contribute to increased mortality and morbidity. The use of automated data acquisition and compliance safety alerts has been widely accepted in many industries and its use may improve operator performance. A study was conducted to evaluate the reaction time of perfusionists with and without the use of compliance alert. A compliance alert is a computer-generated pop-up banner on a pump-mounted computer screen to notify the user of clinical parameters outside of a predetermined range. A proctor monitored and recorded the time from an alert until the perfusionist recognized the parameter was outside the desired range. Group one included 10 cases utilizing compliance alerts. Group 2 included 10 cases with the primary perfusionist blinded to the compliance alerts. In Group 1, 97 compliance alerts were identified and, in group two, 86 alerts were identified. The average reaction time in the group using compliance alerts was 3.6 seconds. The average reaction time in the group not using the alerts was nearly ten times longer than the group using computer-assisted, real-time data feedback. Some believe that real-time computer data acquisition and feedback improves perfusionist performance and may allow clinicians to identify and rectify potentially dangerous situations.

Case report: Remote monitoring using Spectrum Medical Live Vue allows improved response time and improved quality of care for patients on cardiopulmonary support

Clinician rounding on bedside extracorporeal membrane oxygenation (ECMO) is a common coverage practice at many centers across the USA. Occasionally, clinical issues or concerns may go unnoticed for a considerable period of time during the intervals of clinician rounds. We report a case utilizing the LiveVue (Spectrum Medical, Fort Mill, SC) remote monitoring for care of a patient on ECMO. A patient was placed on veno-arterial (VA) ECMO in our intensive care unit, using a Rotaflow centrifugal pump and a Quadrox D polymethylpentene (PMP) fiber oxygenator (both Maquet, Fairfield, NJ). Following ECMO initiation and stabilization, a two-hour rounding schedule was established for the covering perfusionist. On day two, shortly after the perfusionist had rounded, the ECMO flow began fluctuating between 0.1 and 2.1 L/min. A compliance alert (i.e. red flashing notification) was recognized by the perfusion team on a large screen monitor installed in the perfusion pump room. Immediate response from the perfusion team identified venous inflow obstruction due to cannula malposition. The pump revolutions per minute (rpm) and, thus, the resulting flow were temporarily reduced to prevent vessel intimal damage and the surgical team was summoned to reposition the venous cannula. Later in that ECMO run, a steady rise in pre-oxygenator pressure was noted by the perfusionist. This increasingly concerning event was able to be trended and monitored with the LiveVue from a remote location. After a few hours, a compliance alert was noticed again on the LiveVue screen in the pump room. The pre-oxygenator pressure increased by 150 mmHg and the circuit flow decreased by half. Again, the perfusionist response was immediate and an oxygenator change-out ensued. Once more, a potentially dangerous clinical scenario was avoided with continuous critical parameter remote monitoring using the LiveVue system.

Managing the extracorporeal membrane oxygenation (ECMO) circuit integrity and safety utilizing the perfusionist as the “ECMO Specialist”

Extracorporeal membrane oxygenation (ECMO) is an extracorporeal technique of providing both cardiac and respiratory support to patients whose heart and lungs are so severely diseased or damaged that they can no longer serve their function. Neonatal and pediatric ECMO was accepted as practice in the early 1990s and according to the Extracorporeal Life Support Organization, ELSO; of the >50,000 patients registered, 73% have survived extracorporeal life support (ECLS). It is not uncommon to find initial cannulation of a patient receiving ECMO performed by a surgeon and then the maintenance of the patient being left in the hands of various others deemed as the “ECMO Specialists”. The specialist has a broad base of professionals, including: nurses, respiratory therapists, perfusionists and physicians. Each institution, having its own unique training for these individuals, has provided a milieu for education, but does not share an established standard of care. From 2009, after the surge of the H1N1 epidemic, adult ECMO has been increasing; n=53 in 2010 to n=110 in 2012 at our institution. The perfusionist has been the “specialist” for ECMO at our institution since the early 1990s and remained at bedside during ECMO. We have now developed a safe circuit and fiscally responsible staffing model that utilizes a perfusionist and a telemetry-based electronic record keeper, permitting the perfusionist to leave the bedside and interact with the circuit when necessary. This has permitted an expansive growth of ECMO in our intensive care units at our facility incorporating a multidisciplinary collaboration system wide.

Validation of Egg Yolk Antibody Testing as a Method to Determine Influenza Status in White Leghorn Hens

Determination of the avian influenza (AI) status of a flock has traditionally been done by detection of serum antibodies. However, for many diseases, detection of antibodies in egg yolk has been effective in monitoring the disease status of laying flocks. This study compared the utility of egg yolk vs. serum for determining AI status in laying hen flocks. Specific-pathogen-free white leghorn hens were inoculated via the respiratory tract with a low-pathogenic H7N2 AI virus or sterile allantoic fluid or subcutaneously with an inactivated oil emulsion vaccine produced from the same AI virus or normal allantoic fluid. Antibody levels were determined by the agar gel immunodiffusion (AGID) test, the hemagglutination-inhibition (HI) test, and the enzyme-linked immunosorbent assay (ELISA). Anti-influenza antibodies were detected in sera of all live virus-inoculated hens by day 7 postinoculation (PI) (AGID and ELISA tests), but detection of antibodies in egg yolk was delayed by a few days, with all being positive by day 14 PI. Sera from all vaccinated hens were positive by day 14 PI (AGID and ELISA tests), and egg yolk was positive by day 18 PI. The HI test was less sensitive than the ELISA and AGID tests in detecting anti-influenza antibodies in both sera and yolk. Serum and yolk from all control birds remained negative throughout the study. These studies show that currently used serologic tests can detect antibodies in serum and yolk samples from hens exposed to live AI virus or from those that have been vaccinated. Antibody is detected earlier in the serum than in the yolk and antibody is detected earlier from birds exposed to a live infection compared to birds vaccinated with an inactivated oil emulsion vaccine.

Decisions at hand: a decision support system on handhelds

One of the applications of clinical information systems is decision support. Although the advantages of utilizing such aids have never been theoretically disputed, they have been rarely used in practice. The factor that probably often limits the utility of clinical decision support systems is the need for computing power at the very site of decision making--at the place where the patient is interviewed, in discussion rooms, etc. The paper reports on a possible solution to this problem. A decision-support shell LogReg is presented, which runs on a handheld computer. A general schema for handheld-based decision support is also proposed, where decision models are developed on personal computers/workstations, encoded in XML and then transferred to handhelds, where the models are used within a decision support shell. A use case where LogReg has been applied to clinical outcome prediction in crush injury is presented.

Efficacy of vaccines in chickens against highly pathogenic Hong Kong H5N1 avian influenza

In 1997, highly pathogenic (HP) H5N1 avian influenza virus (AIV) caused infections in poultry in Hong Kong and crossed into humans, resulting in a limited number of infections including 18 hospitalized cases and six associated deaths. The unique ability of this, AIV to infect both poultry and people raised a concern for the potential of humans to be biological as well as mechanical vectors of this AIV to poultry. The current study was undertaken to determine if existing vaccines and their technologies could be used during an outbreak to protect poultry. Commercial and experimental inactivated whole H5 AIV and baculovirus-expressed AIV H5 hemagglurinin protein vaccines provided protection from clinical signs and death in chickens after lethal challenge by human-origin HP H5N1 Hong Kong strains 156/97 and 483/97. The commercial and experimental inactivated vaccines had mean protective doses ranging from 0.25 to 0.89, which represents the milligrams of viral protein in the vaccines that provided protection from death in half of the birds. Furthermore, the vaccines reduced the ability of the challenge AIV to replicate in chickens and decreased the recovery of challenge AIV from the enteric and respiratory tracts, but the use of a vaccine will nor totally prevent AI virus replication and shedding. Existing vaccines will protect poultry from mortality and reduce virus replication from the new HP AIV strain that can infect both poultry and humans.

Reanalysis of unruptured intracranial aneurysm management: effect of a new international study on the threshold probabilities

OBJECTIVE

This report updates previous clinical decision analysis for patients with unruptured intracranial aneurysm (UN-AN) based on newly published data and discusses the role of reanalysis in individual decision making.

METHODS

The authors employed probabilities for the natural history of UN-AN and results of preventive surgery based on the report by the International Study of Unruptured Intracranial Aneurysms. Probabilistic sensitivity analysis with Monte Carlo simulation and traditional n-way sensitivity analyses were used to assess the uncertainty of clinical decisions.

RESULTS

The baseline decision in favor of preventive surgery is reversed by new data from the international study. Probabilistic sensitivity analyses revealed several populations showing heterogeneity in terms of strategy selection. One- and two-way sensitivity analyses detected two important factors for decision making: annual rupture rate and utility for knowingly living with UN-AN.

CONCLUSIONS

Annual UN-AN rupture rate and the utility for knowingly living with UN-AN are key factors when deciding on a therapeutic strategy. Also, updating published decision analyses can improve clinical decision making by integrating clinical judgment and newly available clinical data.

Cytarabine added to interferon improves the cost-effectiveness of initial therapy for patients with early chronic phase chronic myelogenous leukemia

The French Chronic Myeloid Leukemia Study Group prospective randomized study results indicate that the addition of cytarabine to alpha interferon (IFN-alpha) increases the rate of major cytogenetic response and prolongs survival in patients with early chronic phase chronic myelogenous leukemia (CML). The French group study design permitted a single crossover to include or discontinue cytarabine or interferon. Endpoints were overall survival, complete hematologic remission (CHR) at six months, and major cytogenetic response at 12 months. We modified a published Markov model that compared IFN-alpha alone to IFN-alpha plus cytarabine and included the possibility of crossover as in the French study. The model permits allogeneic and autologous stem cell transplantation (SCT), and follows cytogenetic response and acceleration of CML through death. Treatment response, toxicity, and survival are drawn from the French Chronic Myeloid Leukemia Study Group population of 810 patients on an intention-to-treat model. Survivals are extended to 62 months based on currently available follow-up. Costs from a United States oncology specialty institution, and state utilities from previous research and a quality-adjusted Time Without Symptoms or Toxicity analysis of the subject study were discounted at 3% per annum. At the median cohort age of 50, cytarabine offers 21 months of added median survival to IFN-alpha, which itself is superior to conventional chemotherapy by 21 months. Cost-effectiveness estimates for cytarabine added to IFN-alpha range from $7,000 per quality-adjusted life year (QALY) to $35,000 per QALY, under all plausible assumptions superior to IFN-alpha alone. The model is sensitive to the quality of life on therapy, as well as to remission rate with additive cytarabine, although the cost-effectiveness calculations are robust over the entire range of clinical assumptions. Based on data from the French study, cytarabine added to IFN-alpha substantially improves the cost-effectiveness of initial therapy for early chronic phase CML.

Predicting patient's long-term clinical status after hip arthroplasty using hierarchical decision modelling and data mining

Construction of a prognostic model is presented for the long-term outcome after femoral neck fracture treatment with implantation of hip endoprosthesis. While the model is induced from the follow-up data, we show that the use of additional expert knowledge is absolutely crucial to obtain good predictive accuracy. A schema is proposed where domain knowledge is encoded as a hierarchical decision model of which only a part is induced from the data while the rest is specified by the expert. Although applied to hip endoprosthesis domain, the proposed schema is general and can be used for the construction of other prognostic models where both follow-up data and human expertise is available.

Cardiac surgical patients exposed to heparin-bonded circuits develop less postoperative cerebral dysfunction than patients exposed to non-heparin-bonded circuits

A prospective randomized trial was used to study the incidence of cerebral dysfunction in patients undergoing cardiopulmonary bypass (CPB) with heparin-bonded vs non-heparin-bonded circuits. Although the etiology of postoperative cerebral dysfunction is controversial, activation of the systemic inflammatory response may play a role. After institutional approval and informed written consent, 39 elective coronary artery bypass (CABG) patients were studied. A battery of neuropsychometric tests (NPMTs) was performed preoperatively, and 5 days and 6 weeks postoperatively. Significant change in NPMT performance was defined as a 25% or greater decrease in postoperative performance, compared to baseline. The number of abnormal tests per patient was calculated. Analysis using the Mann-Whitney rank test was performed for the first follow-up. Patients randomized to heparin-bonded circuits had fewer abnormal NPMTs (>1 abnormal test) on postoperative day 5 (58 vs 70%, n=19 and 20) than patients randomized to non-heparin-bonded circuits. Patients exposed to heparin-bonded circuits had fewer abnormal tests (>1 abnormal test) at 6 weeks (36 vs 63%, n=14 and 16). Results suggested that the attenuation of systemic inflammation by heparin-bonded CPB circuits may lower the incidence of cerebral injury in cardiac surgical patients.

Laboratory testing under managed care dominance in the USA

The uncontrolled escalation of total health care expenditure despite the government's endeavours during the past decades in the USA had led to the rapid infiltration of managed care organisations (MCOs). Traditional hospital based laboratories have been placed in a crucial situation with the advent of the managed care era. A massive reduction of in house testing urged them to develop strategies against financial difficulty. Consolidation and networking, participation in the outreach testing market, and emphasis on point of care/satellite laboratory testing in non-traditional, ambulatory settings are major strategies for the survival of hospital laboratories. Several physicians' office laboratories (POLS) have closed their doors in response both to regulatory restrictions imposed by the Clinical Laboratory Improvement Amendments of 1988 and to managed care infiltration. It seems likely that POLs and hospital laboratories will continue to reduce test volumes, whereas commercial reference laboratories will thrive through contracting with MCOs. In the current climate of managed care dominance in the USA, clinical laboratories are changing their basic operation focus and mission in response to the aggressively changing landscape.

Cost-Effectiveness of interferon alfa-2b added to chemotherapy for high-tumor-burden follicular non-Hodgkin's lymphoma

Recent data from GELF (Groupe d'Etude des Lymphomes Folliculaires) have shown that the addition of interferon alfa-2b (IFN) to a doxorubicin-containing regimen (CHVP: cyclophosphamide, doxorubicin, teniposide and prednisone) prolongs both progression-free survival and overall survival in high-tumor-burden follicular non-Hodgkin's lymphoma. This gain must be weighed against the incremental toxicity and cost of IFN over CHVP alone and the objective here was, to determine the marginal cost-effectiveness of additive IFN in the specific setting of high-tumor-burden follicular non-Hodgkin's lymphoma. Meta-analysis of GELF trial results employing a Markov model was used with three health states: No Progression, Progressive Disease, and Death. Treatment response, survival and toxicity data are drawn from the GELF study. The current study is based on the final analysis of 242 patients (J Clin Oncol 1998;16:2332-2338), with a six year median follow-up for overall survival (median overall survival: not reached for CHVP + IFN vs 5.6 years for CHVP Only, p = 0.008).

MEASUREMENTS

Quality of life data (utilities) are taken from studies with similar dosing of IFN, from Q-TwiST (quality adjusted time without symptoms or toxicity) analysis of the GELF data and from a panel of experts gathered to develop treatment models for high-tumor-burden follicular non-Hodgkin's lymphoma. Costs and quality-adjusted years of life saved were discounted at 3% per annum.

SETTING

Costs determined for university medical centers in the United States. Results showed that, at the median cohort age of 52, IFN add 9.9 quality-adjusted months at an added cost of $13,900 (marginal cost-effectiveness of $16,900 per quality-adjusted life year, or QALY). A more complex, two-stage model approximates the actual cohort survival curves much better than a simple, one-stage model, but both models yield essentially the same marginal cost-effectiveness. Sensitivity analysis to quality of life on IFN shows marginal cost-effectiveness ranging from $15,200/QALY (no penalty for IFN) to $21,300/QALY (20% quality adjustment, greater than that reported). The model is quite insensitive to the probability of IFN toxicity. The model is moderately sensitive to the efficacy of IFN in delaying progression, particularly in the first 18 months (pProgI), but the marginal cost-effectiveness does not rise to $50,000/QALY until pProgI increases 220% from the baseline. Although the model is moderately sensitive to the cost of IFN (cIFN), marginal cost-effectiveness is below $50,000/QALY for values of cIFN below $2580/month (baseline cIFN = $850/month, corresponding to a marginal cost-effectiveness of $16,900/QALY in the baseline case). If the model is modified to reflect the 14% overall survival advantage at five years found in trials utilizing more intensive initial chemotherapy (including the GELF trial), then the marginal cost-effectiveness drops to $11,900/QALY in the baseline case. In condusion, based on data from the GELF study, low-dose interferon alfa-2b is cost-effective when added to CHVP therapy in the treatment of high-tumor-burden follicular non-Hodgkin's lymphoma. The analysis is robust: the model employs very conservative assumptions, and additive IFN remains cost-effective over wide ranges of variables in sensitivity analyses. The marginal cost-effectiveness is best expressed as being in the range of $12,000/QALY to $17,000/QALY in the baseline case. A simple Markov model can be used to describe treatment regimens with distinct periods of therapy.

Fatal encephalitis and myocarditis in young domestic geese (Anser anser domesticus) caused by West Nile virus

During 1999 and 2000, a disease outbreak of West Nile (WN) virus occurred in humans, horses, and wild and zoological birds in the northeastern USA. In our experiments, WN virus infection of young domestic geese (Anser anser domesticus) caused depression, weight loss, torticollis, opisthotonus, and death with accompanying encephalitis and myocarditis. Based on this experimental study and a field outbreak in Israel, WN virus is a disease threat to young goslings and viremia levels are potentially sufficient to infect mosquitoes and transmit WN virus to other animal species.

Predictive model for survival at the conclusion of a damage control laparotomy

BACKGROUND

We employed modern statistical and data mining methods to model survival based on preoperative and intraoperative parameters for patients undergoing damage control surgery.

METHODS

One hundred seventy-four parameters were collected from 68 damage control patients in prehospital, emergency center, operating room, and intensive care unit (ICU) settings. Data were analyzed with logistic regression and data mining. Outcomes were survival and death after the initial operation.

RESULTS

Overall mortality was 66.2%. Logistic regression identified pH at initial ICU admission (odds ratio: 4.4) and worst partial thromboplastin time from hospital admission to ICU admission (odds ratio: 9.4) as significant. Data mining selected the same factors, and generated a simple algorithm for patient classification. Model accuracy was 83%.

CONCLUSION

Inability to correct pH at the conclusion of initial damage-control laparotomy and the worst PTT can be predictive of death. These factors may be useful to identify patients with a high risk of mortality.

Decision analysis of prophylactic treatment for patients with high-risk esophageal varices

BACKGROUND

Clinical decision analyses were conducted to quantify the uncertainty and to identify important factors in selection of prophylactic therapy for patients with esophageal varices.

METHODS

A Markov model compared variceal ligation, beta-blockers, and "watchful waiting" strategies in terms of bleeding-free life years. Transition probabilities were obtained from meta-analyses of published data. A hypothetical 50-year-old white man with high-risk esophageal varices and cirrhosis served as the prototypical baseline case. Traditional n-way sensitivity analyses were applied to clarify the influence of each factor, and Monte Carlo probabilistic sensitivity analyses were used to investigate clinical uncertainty.

RESULTS

Probabilistic sensitivity analyses demonstrated that 77.0% of hypothetical cases had more bleeding-free life years after variceal ligation, whereas 23% had more when treated with beta-blockers. On the basis of one-way sensitivity analyses, only 2 factors (variceal bleeding rates after ligation and treatment with beta-blockers) influenced the strategy choice.

CONCLUSIONS

Variceal ligation is an effective prophylactic therapy in many cases, but nearly one quarter of patients with high-risk esophageal varices and cirrhosis may benefit more from prophylactic treatment with beta-blockers. Additional clinical studies identifying key variceal bleeding risk factors may lead to more effective clinical decision making for these patients.

Pathogenicity of West Nile virus for turkeys

In the fall of 1999, West Nile virus (WNV) was isolated during an outbreak of neurologic disease in humans, horses, and wild and zoological birds in New York, Connecticut, and New Jersey. Turkeys could potentially be a large reservoir for WNV because of the high-density turkey farming and the presence of large wild turkey populations in the eastern seaboard of the United States. Little is known about the pathogenicity of WNV in domestic or wild turkeys. Specific-pathogen-free 3-wk-old turkeys were inoculated subcutaneously with 10(3.3) mean tissue culture infective doses of a WNV strain isolated fromthe index case in a New York crow. No clinical signs were observed in the turkeys over the 21 days of the experiment. One turkey died abruptly at 8 days postinoculation (DPI). Many turkeys developed viremia between 2 and 10 DPI, but the average level of virus was very low, less than needed to efficiently infect mosquitos. Low levels of WNV were detected in feces on 4 and 7 DPI, but no virus was isolated from oropharyngeal swabs. WNV wasnot transmitted from WNV-inoculated to contact-exposed turkeys. All WNV-inoculated poults seroconverted on 7 DPI. In the turkey that died, WNV was not isolated from intestine, myocardium, brain, kidney, or cloacal and oropharyngeal swabs, but sparse viral antigen was demonstrated by immunohistochemistry in the heart and spleen. Turkeys in contact with WNV-inoculated turkeys and sham-inoculated controls lacked WNV specific antibodies,and WNV was not isolated from plasma and cloacal and oropharyngeal swabs. These data suggest that WNV lacks the potential to be a major new disease of turkeys and that turkeys will not be a significant amplifying host for infecting mosquitos.

A randomized trial of antithrombin concentrate for treatment of heparin resistance

BACKGROUND

Heparin resistance is an important clinical problem traditionally treated with additional heparin or fresh frozen plasma. We undertook a randomized clinical trial to determine if treatment with antithrombin (AT) concentrate is effective for treating this condition.

METHODS

Patients requiring cardiopulmonary bypass who were considered to be heparin resistant (activated clotting time < 480 seconds after > 450 IU/kg heparin) were randomized to receive either 1000 U AT or additional heparin.

RESULTS

AT concentrate was effective in 42 of 44 patients (96%) for immediately obtaining a therapeutic activated clotting time. This compared favorably to 28 of 41 patients (68%) treated with additional heparin (p = 0.001). All patients who failed heparin therapy were successfully treated with AT. The patients receiving AT required less time to obtain an adequate ACT but there was no difference in clinical outcomes among the groups. Study patients had deficient AT activity at baseline (56%+/-25%), which improved in those given AT concentrate (75%+/-31% versus 50%+/-23%, p < 0.0005).

CONCLUSIONS

Heparin resistance is frequently associated with AT deficiency. Treating this deficiency with AT concentrate is more effective and faster for obtaining adequate anticoagulation than using additional heparin.

Machine learning for survival analysis: a case study on recurrence of prostate cancer

Machine learning techniques have recently received considerable attention, especially when used for the construction of prediction models from data. Despite their potential advantages over standard statistical methods, like their ability to model non-linear relationships and construct symbolic and interpretable models, their applications to survival analysis are at best rare, primarily because of the difficulty to appropriately handle censored data. In this paper we propose a schema that enables the use of classification methods--including machine learning classifiers--for survival analysis. To appropriately consider the follow-up time and censoring, we propose a technique that, for the patients for which the event did not occur and have short follow-up times, estimates their probability of event and assigns them a distribution of outcome accordingly. Since most machine learning techniques do not deal with outcome distributions, the schema is implemented using weighted examples. To show the utility of the proposed technique, we investigate a particular problem of building prognostic models for prostate cancer recurrence, where the sole prediction of the probability of event (and not its probability dependency on time) is of interest. A case study on preoperative and postoperative prostate cancer recurrence prediction shows that by incorporating this weighting technique the machine learning tools stand beside modern statistical methods and may, by inducing symbolic recurrence models, provide further insight to relationships within the modeled data.

Opportunistic discovery of occult disease by use of test panels in new, symptomatic primary care outpatients: yield and cost of case finding

BACKGROUND

Diagnostic test panels have been advocated by the Japan Society of Clinical Pathology for evaluation of presenting complaints of new outpatients in primary care medicine. The tests have additional potential utility for opportunistic finding of asymptomatic diseases, but data are lacking on the number of new conditions identified by the test panels and on the cost per identified case.

METHODS

We studied 540 new, symptomatic patients at the Comprehensive Medicine Clinics of National Defense Medical College during 1991-1997. All underwent testing with the "Essential Laboratory Tests" panel (2) [ELT(2) panel]. This panel includes hematologic tests, urinalysis, total protein, C-reactive protein, albumin, cholesterol, triglycerides, glucose, urea nitrogen, creatinine, uric acid, serum protein fractionation, six enzymes, and optional tests, including x-rays, electrocardiogram, and fecal occult blood.

RESULTS

The ELT(2) panel uncovered 276 additional diagnoses of asymptomatic disease or abnormal health status. The most frequent occult condition was hyperlipidemia (100 cases) followed by liver dysfunction (53 cases). Clinical efficiency of the panel (occult diseases/patient) varied depending on the category of tentative initial diagnosis, with the highest efficiency in patients with cardiovascular disease. We created smaller panels by combining 11 basic tests [called the ELT(1) baseline panel] with one or more additional tests from the ELT(2) and analyzed their cost-effectiveness. Addition of four tests (total cholesterol, alanine aminotransferase, glucose, and uric acid) improved both clinical efficiency (0.41 occult disease/patient) and economic efficiency [ 2372 yen (approximately $22.50 US)/occult disease] at a cost-effectiveness of 177 yen per incremental case of occult disease. Addition of further tests decreased cost-effectiveness.

CONCLUSIONS

Although the ELT(2) panel has supplemental utility for opportunistic screening of some significant, occult diseases and conditions, universal utilization of the full panel is not supported by the cost-effectiveness found in this study.

Vaccines protect chickens against H5 highly pathogenic avian influenza in the face of genetic changes in field viruses over multiple years

Inactivated whole avian influenza (AI) virus vaccines, baculovirus-derived AI haemagglutinin vaccine and recombinant fowlpoxvirus-AI haemagglutinin vaccine were tested for the ability to protect chickens against multiple highly pathogenic (HP) H5 AI viruses. The vaccine and challenge viruses, or their haemagglutinin protein components, were obtained from field AI viruses of diverse backgrounds and included strains obtained from four continents, six host species, and isolated over a 38-year-period. The vaccines protected against clinical signs and death, and reduced the number of chickens shedding virus and the titre of the virus shed following a HP H5 AI virus challenge. Immunization with these vaccines should decrease AI virus shedding from the respiratory and digestive tracts of AI virus exposed chickens and reduce bird-to-bird transmission. Although most consistent reduction in respiratory shedding was afforded when vaccine was more similar to the challenge virus, the genetic drift of avian influenza virus did not interfere with general protection as has been reported for human influenza viruses.

Naive Bayesian-based nomogram for prediction of prostate cancer recurrence

This paper introduces a schema with naive-Bayesian classifier and patient weighting technique to develop a prostate cancer recurrence prediction model from patient data. We propose the graphical presentation of naive-Bayesian classifier with a nomogram, which can be used both for prediction or can provide means to data analysis. The resulting model was experimentally evaluated; the results were favorable both in terms of interpretability and predictive accuracy.

[A cost-effectiveness analysis of a pre-visit testing system for new outpatients in primary care medicine]

We evaluated cost-effectiveness parameters of common diagnostic test panels advocated by the Japan Society of Clinical Pathology in order to determine the validity of pre-visit testing of these test panels for new outpatients with some defined symptoms. The "Essential Laboratory Tests(ELT) (2)" panel was universally applied to 540 new outpatients who visited the Comprehensive Medicine Clinics in the National Defense Medical College and its affiliated hospital. A "useful result(UR)", the unit of usefulness of the ELT, was assigned by assessing the impact of its results on physician's diagnosis- or decision-making. Patients were classified into 7 major symptom groups according to their chief complaint, and clinical effectiveness(UR/patient), economic efficiency(cost/UR) and cost-effectiveness(delta cost/delta UR) were analyzed in each patient group. Clinical effectiveness ranged from 1.38(renal/urinary tract symptoms) to 0.27 UR/patient(neurological symptoms) with a cost disparity from yen 1,222 to yen 5,946/UR between these patient groups. Substantial decreases in clinical effectiveness were demonstrated in all patient groups with the ELT(1)-testing alone in a simulation study; however, cost-effectiveness parameters still remain in excellent values in the renal/urinary tract symptom and infection/inflammation-related symptom groups(1.13 and 0.77 UR/patient at a cost of yen 836 and yen 1,181/UR, respectively). The addition of some ELT(2)-specific test items such as AST, ALT to the ELT(1) baseline panel improved clinical effectiveness of the ELT(1) in lassitude/exhaustive symptom group at a minimal cost increment. This study verified the validity of the ELT(1) as a panel for pre-visit testing in patients with renal/urinary tract symptoms and infection/inflammation-related symptoms, but not in those with other symptoms.

Protection against diverse highly pathogenic H5 avian influenza viruses in chickens immunized with a recombinant fowlpox vaccine containing an H5 avian influenza hemagglutinin gene insert

A recombinant fowlpox vaccine with an H5 hemagglutinin gene insert protected chickens against clinical signs and death following challenge by nine different highly pathogenic H5 avian influenza viruses. The challenge viruses had 87.3 to 100% deduced hemagglutinin amino acid sequence similarity with the recombinant vaccine, and represented diversely geographic and spatial backgrounds; i.e. isolated from four different continents over a 38 year period. The recombinant vaccine reduced detectable infection rates and shedding titers by some challenge viruses. There was a significant positive correlation in hemagglutinin sequence similarity between challenge viruses and vaccine, and the ability to reduce titers of challenge virus isolated from the oropharynx (r(s)=0.783, P=0.009), but there was no similar correlation for reducing cloacal virus titers (r(s)=-0.100, P=0.78). This recombinant fowlpox-H5 avian influenza hemagglutinin vaccine can provide protection against a variety of different highly pathogenic H5 avian influenza viruses and frequent optimizing of the hemagglutinin insert to overcome genetic drift in the vaccine may not be necessary to provide adequate field protection.

Failure of a recombinant fowl poxvirus vaccine containing an avian influenza hemagglutinin gene to provide consistent protection against influenza in chickens preimmunized with a fowl pox vaccine

Vaccines against mildly pathogenic avian influenza (AI) have been used in turkeys within the United States as part of a comprehensive control strategy. Recently, AI vaccines have been used in control programs against highly pathogenic (HP) AI of chickens in Pakistan and Mexico. A recombinant fowl pox-AI hemagglutinin subtype (H) 5 gene insert vaccine has been shown to protect specific-pathogen-free chickens from HP H5 AI virus (AIV) challenge and has been licensed by the USDA for emergency use. The ability of the recombinant fowl pox vaccine to protect chickens preimmunized against fowl pox is unknown. In the current study, broiler breeders (BB) and white leghorn (WL) pullets vaccinated with a control fowl poxvirus vaccine (FP-C) and/or a recombinant fowl poxvirus vaccine containing an H5 hemagglutinin gene insert (FP-HA) were challenged with a HP H5N2 AIV isolated from chickens in Mexico. When used alone, the FP-HA vaccine protected BB and WL chickens from lethal challenge, but when given as a secondary vaccine after a primary FP-C immunization, protection against a HP AIV challenge was inconsistent. Both vaccines protected against virulent fowl pox challenge. This lack of consistent protection against HPAI may limit use to chickens without previous fowl pox vaccinations. In addition, prior exposure to field fowl poxvirus could be expected to limit protection induced by this vaccine.

Common diagnostic test panels for clinical evaluation of new primary care outpatients in Japan: a cost-effectiveness evaluation

BACKGROUND

The Japan Society of Clinical Pathology (JSCP) has developed a guideline for common diagnostic test utilization in new primary care outpatients. To determine the scientific and economic validity of the JSCP panel testing system, we analyzed cost-effectiveness parameters of test panels advocated.

METHODS

The "Essential Laboratory Tests" panel (2) [ELT(2) panel], a package of common diagnostic tests added to the ELT(1) baseline health-status screening panel, was applied to 540 new outpatients who visited the Comprehensive Medicine Clinics in an academic medical center during 1991 to 1997. A "useful result" (UR) of testing was defined as a finding that contributed to a change in a physician's diagnosis- or decision-making, relating to a "tentative initial diagnosis" (TID) obtained from history and physical examination alone.

RESULTS

Clinical usefulness was demonstrated in 259 patients with ELT(2), in whom 398 URs were generated. Clinical effectiveness (UR/TID) ranged from 1.65 (hematological) to 0.088 (neurological disease), with a cost disparity from yen1251 ( approximately $10) to yen23 037 ( approximately $200) per UR. A total of 1137 tests generated URs. We further assessed the clinical effectiveness and economic efficiency (cost/UR) of ELT(1) and restructured panels. Use of the ELT(1) alone generated 244 URs in 167 patients. The poor efficiency of the ELT(1) panel was markedly improved with the addition of certain ELT(2)-specific tests in liver/pancreatobiliary, metabolic/endocrine, and cardiovascular disease groups.

CONCLUSIONS

A wide disparity in the utility of ELT panels in different patient groups does not support the JSCP recommendation of their routine use for new outpatients. Selective test combinations should be used in selected patient groups.

Taking a corporate approach to information technology in an academic medical center

Academic health science centers employ faculty and research staff who demand and merit a high level of information technology (IT) support. Often their needs outstrip the ability of IT to provide adequate service. The authors review the recent history of IT at Baylor College of Medicine, beginning with the critical review of its operations undertaken outside consultants in 1996. The analysis led to a strategic planning strategic planning retreat at which three infrastructure projects and three systems projects were identified. As the IT program executed these projects, it transformed itself into a more modern organization able to provide higher levels of service to faculty and staff. Those involved in these changes at Baylor were able to successfully adopt a corporate model of information services support without sacrificing the college's academic focus.

The metrics process: Baylor's development of a "report card" for faculty and departments

In 1996, Baylor College of Medicine began the first year of its "metrics process," collecting, analyzing, and reporting data on the performance of each individual faculty member and each department in achieving the school's missions of education, patient care, research, service, and finance. This article is a report of the first two years of the process, with updates about the 1999 process, future plans, and lessons learned. The primary goal of the metrics process is to provide meaningful data to assess and improve the performance of faculty and departments across all missions. The authors (1) indicate the categories chosen, within each mission of the school, for measuring faculty time and effort (e.g., patient care, with or without learners) and state the measures chosen (e.g., percentage of time); (2) describe the development of questionnaires in 1996 and 1997 to acquire data from faculty, in the chosen categories and measures, about the time and effort they spent; and (3) report highlights of the resulting departmental data that were gathered in 1997. Among the key categories and units of measure chosen for measuring faculty (and departmental) time and effort are research grant dollars (total and per research full-time equivalent, or FTE); basic research grant dollars per square foot of laboratory space; percentage of faculty who spend at least 50% of their time in research who are National Institutes of Health principal investigators; numbers of inpatient and outpatient visits per evaluation and management FTE; total relative value units (RVUs) per patient-care FTE; patient-care income/RVU and expense/RVU for total faculty and support staff; percentage of faculty with at least one leadership position in a state or national organization; and income in excess of expense, by mission (e.g., patient care). Results of comparing data from the first two years of the metrics process demonstrate marked improvements in performance for most research measures (i.e., items of measurement agreed upon for the metrics process). The process is continually being redeveloped; the ultimate challenge is to place the objective measurements in a context where less objective qualities (e.g., innovation) also figure importantly in the evaluation and fostering of excellence. The metrics process is providing important management data, encouraging significant discussions among faculty and chairs about performance and accountability, and aiding greatly in departmental goal-setting and ultimately in determining the overall performance of the school.

Treatment of primary peritoneal mesothelioma by hyperthemic intraperitoneal chemotherapy

Perfusion of the peritoneal cavity with chemotherapy agents under hyperthermic conditions has been utilized by several investigators in the treatment of intra-abdominal malignancies. Based on the concept that hyperthermia may potentiate the cytotoxic effects of chemotherapeutic agents, we embarked on a clinical trial of two-stage peritoneal chemotherapy for patients with primary peritoneal mesothelioma, a neoplasm unresponsive to traditional systemic chemotherapeutic regimens. In stage I, patients underwent surgical debulking of gross disease and placement of an intraperitoneal infusion catheter, through which intraperitoneal chemotherapy was administered for four months. Stage II consisted of debulking of residual tumor, placement of two transabdominal perfusion cannulae and administration of high-dose intraperitoneal chemotherapy at 40 degrees C using a simple, disposable perfusion circuit. Flow rates were maintained at 1 l/min, and inflow and outflow temperatures maintained at 42 and 40 degrees C, respectively. To date, three patients have undergone both phases of the protocol, with no perioperative complications related to either hyperthermia or end-organ toxicity. One patient died of progressive disease after three months, and two patients are alive and well. One patient developed a small bowel anastomotic leak three weeks after operation. In summary, intraoperative hyperthermic peritoneal chemotherapy may play a role in novel approaches to the treatment of peritoneal malignancies previously unresponsive to traditional chemotherapeutic regimens.

Inhaled nitric oxide improves hemodynamics in patients with acute pulmonary hypertension after high-risk cardiac surgery

Severe pulmonary hypertension and right-sided circulatory failure (RSCF) represent an increasing cause of morbidity and mortality in patients undergoing high-risk cardiac surgery. Increased pulmonary vascular resistance in the setting of cardiopulmonary bypass (CPB) may further lead to decrease blood flow across the pulmonary vascular bed; thereby decreasing left ventricular filling and cardiac output. Current management techniques for RSCF include both nonspecific vasodilator and inotropic agents (often limited by systemic hypotension) and the placement of right ventricular assist devices (associated with increased perioperative morbidity). Inhaled nitric oxide (NOi) represents a novel, specific pulmonary vasodilator that has been proven efficacious in these clinical settings. We evaluated 34 patients in 38 operations who underwent cardiac surgery at Columbia Presbyterian Medical Center, and who received NOi (20 ppm) through a modified ventilatory circuit for hemodynamically significant elevations in pulmonary vascular resistance. Nine patients underwent cardiac transplantation, three patients bilateral lung transplantation, 16 patients left ventricular assist device placement and 10 patients routine cardiac surgery. Patients receiving NOi exhibited substantial reductions in mean pulmonary artery pressure (mPAP) (34.6 +/- 2.0 to 26.0 +/- 1.7 mmHg, p < 0.0001), with improvements in systemic hemodynamics, mean arterial pressure (68 +/- 3.1 to 75.9 +/- 2.0 mmHg, p = 0.006). In five cases, patients could not be weaned from CPB until NOi was administered. Patients were maintained on NOi from 6 to 240 h postoperatively (median duration 36 h). Inhaled NO induces substantial reductions in mPAP and increases in both cardiac index and systemic blood pressure in patients displaying elevated pulmonary hemodynamics after high-risk cardiac surgery. NO is, therefore, a useful adjunct in these patients in whom acute pulmonary hypertension threatens right ventricular function and hemodynamic stability.

The effects of a fixed-fee reimbursement system introduced by the Federal Government on laboratory testing in the United States

Rapid growth of health care expenditures during the 1970s in the United States led to implementation of a prospective payment system (PPS) based on diagnosis-related groups (DRG) for Medicare inpatient reimbursement in 1983. With the introduction of DRG/PPS, hospitals encouraged earlier discharges and discouraged admission of patients who may require expensive services. Patient care has moved into more outpatient and non-hospital settings which have been less regulated and paid on a cost-reimbursement basis. The change of reimbursement system has converted hospital laboratories from "profit center" under the fee-for-service reimbursement practice to possible "cost center" at least for inpatient laboratory services with the advent of DRG/PPS. Hospitals have reduced laboratory operating expenses by constraining laboratory growth and development. Laboratory testing in non-hospital settings such as physicians' office laboratories, which were exempt from license and quality control by governmental regulations, has increased exponentially since implementation of DRG/PPS. To improve the quality of laboratory testing in such unregulated laboratories, the federal government has promulgated the Clinical Laboratory Improvement Amendments of 1988 (CLIA '88), requiring on-site survey and license under CLIA '88 for all laboratories in the United States regardless of the size, complexity, or location of laboratory. Implementation of DRG/PPS resulted in a temporary success in reducing Medicare Part A budget growth, but had only a small impact to slow the actual growth of total national health care expenditures or laboratory-related expenditures. Nevertheless, the change of reimbursement practice has created a large incentive to reduce unnecessary resource utilization, and cost-effective laboratory testing has become an essential concept during the DRG/PPS era.

Management of unruptured intracranial aneurysm in Japan: a Markovian decision analysis with utility measurements based on the Glasgow Outcome Scale

The purpose of this study was to analyze the management of individual patients with unruptured intracranial aneurysms (UN-ANs) using a decision-analytic approach. Transition probabilities among Glasgow Outcome Scale (GOS) categories were estimated from the published literature and data from patients who had been treated at Kitasato University Hospital. Utilities were obtained from 140 health providers based principally on the GOS. Baseline analysis for a healthy 40-year-old man with an anterior UN-AN less than 10 mm in diameter showed that the quality-adjusted life expectancies for preventive operation and follow-up were 15.34 and 14.66 years, respectively. For a follow-up strategy to be preferred, the annual rupture rate had to be as low as 0.9%. These results were sustained through extensive sensitivity analysis. The results support preventive operation for UN-ANs, and identify problems that can be clarified with a well-designed stratified clinical trial.

The danger of applying group-level utilities in decision analyses of the treatment of localized prostate cancer in individual patients

The optimal management strategy for men who have localized prostate cancer remains controversial. This study examines the extent to which suggested treatment based on the perspective of a group or society agrees with that derived from individual patients' preferences. A previously published decision analysis for localized prostate cancer was used to suggest the treatment that maximized quality-adjusted life expectancy. Two treatment recommendations were obtained for each patient: the first (group-level) was derived using the mean utilities of the cohort; the second (individual-level) used his own set of utilities. Group-level utilities misrepresented 25-48% of individuals' preferences depending on the grade of tumor modeled. The best kappa measure achieved between group and individual preferences was 0.11. The average quality-adjusted life years lost due to misrepresentation of preference was as high as 1.7 quality-adjusted life years. Use of aggregated utilities in a group-level decision analysis can ignore the substantial variability at the individual level. Caution is needed when applying a group-level recommendation to the treatment of localized prostate cancer in an individual patient.

Experiments to determine whether recursive partitioning (CART) or an artificial neural network overcomes theoretical limitations of Cox proportional hazards regression

New computationally intensive tools for medical survival analyses include recursive patitioning (also called CART) and artificial neural networks. A challenge that remains is to better understand the behavior of these techniques in effort to know when they will be effective tools. Theoretically they may overcome limitations of the traditional multivariable survival technique, the Cox proportional hazards regression model. Experiments were designed to test whether the new tools would, in practice, overcome these limitations. Two datasets in which theory suggests CART and the neural network should outperform the Cox model were selected. The first was a published leukemia dataset manipulated to have a strong interaction that CART should detect. The second was a published cirrhosis dataset with pronounced nonlinear effects that a neural network should fit. Repeated sampling of 50 training and testing subsets was applied to each technique. The concordance index C was calculated as a measure of predictive accuracy by each technique on the testing dataset. In the interaction dataset, CART outperformed Cox (P < 0.05) with a C improvement of 0.1 (95% CI, 0.08 to 0.12). In the nonlinear dataset, the neural network outperformed the Cox model (P < 0.05), but by a very slight amount (0.015). As predicted by theory, CART and the neural network were able to overcome limitations of the Cox model. Experiments like these are important to increase our understanding of when one of these new techniques will outperform the standard Cox model. Further research is necessary to predict which technique will do best a priori and to assess the magnitude of superiority.