[What's new in hyperkalemia management?]

Hyperkalemia is common in everyday clinical practice, and is a major risk factor for mortality. It mainly affects patients with chronic renal failure (CKD), diabetes or receiving treatment with inhibitors of the renin-angiotensin-aldosterone system (iRAAS). Therapeutic management aims not only to avoid the complications of hyperkalemia, but also to avoid discontinuation of cardio- and nephroprotective treatments such as iRAAS. The use of polystyrene sulfonate, widely prescribed, is often limited by patient acceptability. Recent data have cast doubt on its safety, particularly in terms of digestive tolerance. Two new potassium exchange molecules have appeared on the market: patiromer and zirconium sulfonate. Their value in clinical practice, and their acceptability in the event of prolonged prescription, remain to be demonstrated. The combination of a thiazide diuretic or an inhibitor of the sodium-glucose cotransporter type 2 (iSGLT2) with iRAAS therapy in CKD, may also improve control of kalemia. At present, there are no recommendations for the positioning of the various hypokalemic treatments. The choice of these treatments must be adapted to the patient's pathologies and consider the other expected effects of these molecules.

Synergistic use of bioactive agents for the management of different skin conditions: an overview of biological activities

Recently, many plant-derived bioactive agents have been included in dermo-cosmetics formulations. This leads to an extensive portfolio of innovative products with an expanded range of benefits, including anti-aging, antioxidant, hydrating and depigmenting. Although different technologies drawing on science and nature are used to create these high-performing molecules, there remains some debate about the mechanism of action of the natural bioactive ingredients within dermo-cosmetics. This review recapitulates the main biological mechanisms underlying the activity of natural active ingredients, with a specific focus on their synergistic use for the management of common, yet quite specific, skin conditions. A total of 28 plant-derived bioactives were selected from the Givaudan Active Beauty (Argenteuil, France) portfolio, a multinational company specializing in innovative natural actives research. An extensive literature review about their biological activity was conducted by a PubMed search using different keywords. No language or publication date restrictions were used. Givaudan Active Beauty data on file were also considered. The bioactive ingredients were described according to the pathogenetic mechanisms underlying 10 common skin conditions that dermo-cosmetics may address. Literature data have shown that plant-derived bioactives are involved in a wide range of biological mechanisms showing anti-inflammatory, antioxidant, and moisturizing properties, along with skin barrier protection and collagen synthesis activities. As a result, different combinations of bioactives within dermo-cosmetics can be defined to counteract simultaneously the different pathogenetic mechanisms underlying different skin conditions. Available literature supports the synergistic use of plant-derived bioactive agents within dermo-cosmetics as a viable and safe option for managing the most common skin conditions.

Metallization of Shock-Compressed Liquid Ammonia

Ammonia is predicted to be one of the major components in the depths of the ice giant planets Uranus and Neptune. Their dynamics, evolution, and interior structure are insufficiently understood and models rely imperatively on data for equation of state and transport properties. Despite its great significance, the experimentally accessed region of the ammonia phase diagram today is still very limited in pressure and temperature. Here we push the probed regime to unprecedented conditions, up to ∼350  GPa and ∼40 000  K. Along the Hugoniot, the temperature measured as a function of pressure shows a subtle change in slope at ∼7000  K and ∼90  GPa, in agreement with ab initio simulations we have performed. This feature coincides with the gradual transition from a molecular liquid to a plasma state. Additionally, we performed reflectivity measurements, providing the first experimental evidence of electronic conduction in high-pressure ammonia. Shock reflectance continuously rises with pressure above 50 GPa and reaches saturation values above 120 GPa. Corresponding electrical conductivity values are up to 1 order of magnitude higher than in water in the 100 GPa regime, with possible significant contributions of the predicted ammonia-rich layers to the generation of magnetic dynamos in ice giant interiors.

X-ray powder diffraction in reflection geometry on multi-beam kJ-type laser facilities

An ultrafast x-ray powder diffraction setup for laser-driven dynamic compression has been developed at the LULI2000 laser facility. X-ray diffraction is performed in reflection geometry from a quasi-monochromatic laser-generated plasma x-ray source. In comparison to a transmission geometry setup, this configuration allows us to probe only a small portion of the compressed sample, as well as to shield the detectors against the x-rays generated by the laser-plasma interaction on the front side of the target. Thus, this new platform facilitates probing of spatially and temporarily uniform thermodynamic conditions and enables us to study samples of a large range of atomic numbers, thicknesses, and compression dynamics. As a proof-of-concept, we report direct structural measurements of the bcc-hcp transition both in shock and ramp-compressed polycrystalline iron with diffraction signals recorded between 2θ ∼ 30° and ∼150°. In parallel, the pressure and temperature history of probed samples is measured by rear-side visible diagnostics (velocimetry and pyrometry).

Laser-driven shock compression of "synthetic planetary mixtures" of water, ethanol, and ammonia

Water, methane, and ammonia are commonly considered to be the key components of the interiors of Uranus and Neptune. Modelling the planets' internal structure, evolution, and dynamo heavily relies on the properties of the complex mixtures with uncertain exact composition in their deep interiors. Therefore, characterising icy mixtures with varying composition at planetary conditions of several hundred gigapascal and a few thousand Kelvin is crucial to improve our understanding of the ice giants. In this work, pure water, a water-ethanol mixture, and a water-ethanol-ammonia "synthetic planetary mixture" (SPM) have been compressed through laser-driven decaying shocks along their principal Hugoniot curves up to 270, 280, and 260 GPa, respectively. Measured temperatures spanned from 4000 to 25000 K, just above the coldest predicted adiabatic Uranus and Neptune profiles (3000-4000 K) but more similar to those predicted by more recent models including a thermal boundary layer (7000-14000 K). The experiments were performed at the GEKKO XII and LULI2000 laser facilities using standard optical diagnostics (Doppler velocimetry and optical pyrometry) to measure the thermodynamic state and the shock-front reflectivity at two different wavelengths. The results show that water and the mixtures undergo a similar compression path under single shock loading in agreement with Density Functional Theory Molecular Dynamics (DFT-MD) calculations using the Linear Mixing Approximation (LMA). On the contrary, their shock-front reflectivities behave differently by what concerns both the onset pressures and the saturation values, with possible impact on planetary dynamos.

MAVEN observations of the response of Mars to an interplanetary coronal mass ejection

Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.

Early MAVEN Deep Dip campaign reveals thermosphere and ionosphere variability

The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above the well-mixed atmosphere, the layer of peak extreme ultraviolet heating and primary reservoir for atmospheric escape. In situ measurements of the upper atmosphere reveal previously unmeasured populations of neutral and charged particles, the homopause altitude at approximately 130 kilometers, and an unexpected level of variability both on an orbit-to-orbit basis and within individual orbits. These observations help constrain volatile escape processes controlled by thermosphere and ionosphere structure and variability.

Laser generated guided waves and finite element modeling for the thickness gauging of thin layers

In this paper, nondestructive testing has been performed on a thin gold layer deposited on a 2 in. silicon wafer. Guided waves were generated and studied using a laser ultrasonic setup and a two-dimensional fast Fourier transform technique was employed to obtain the dispersion curves. A gold layer thickness of 1.33 microm has been determined with a +/-5% margin of error using the shape of the two first propagating modes, assuming for the substrate and the layer an uncertainty on the elastic parameters of +/-2.5%. A finite element model has been implemented to validate the data post-treatment and the experimental results. A good agreement between the numerical simulation, the analytical modeling and the experimentations has been observed. This method was considered suitable for thickness layer higher than 0.7 microm.

Laser ultrasonics and neural networks for the characterization of thin isotropic plates

Nondestructive testing has been performed on a thin copper plate. Lamb waves were generated and studied with a noncontact method, using a laser ultrasonic setup. A two-dimensional Fourier transform technique has been employed to obtain the dispersion curves, revealing numerous symmetric and antisymmetric modes. The inverse problem, in other words, the determination of the thickness and the elastic constants of the tested plate, has been solved by means of a feed-forward neural network. These parameters were then evaluated simultaneously, the dispersion curves being entirely fitted. The experimental results show good agreement with the theoretical model. This inversion method was found to be prompt and easy to automate.

[Evolution of the treatment of chronic post-traumatic aneurysms of the descending thoracic aorta: 30 years experience]

The authors present the early and late results of a series of 40 patients treated for chronic post-traumatic aneurysms of the descending thoracic aorta from 1975 to 2005. With the exception of a patient who died of an intra-pleural rupture before surgery, the patients were treated by aortotomy and prosthetic graft (N=17), aortotomy and direct suture (N=17) or endoprosthesis (N=5). The use of distal aortic perfusion in 22 patients enabled 17 direct sutures (77.3%) thanks to extensive mobilisation of the aortic arch. Endoprostheses have been used since 1997 in high surgical risk patients with severe comorbid conditions. There were no deaths, one transient paraparesia after simple aortic clamping, one reoperation for a haemothorax and four cases of dysphonia due to paralysis of the recurrent laryngeal nerve. Thirty-five patients (90%) were followed up for an average of 119.7 +/- 16.4 months. There were no clinical complications and the late morphological results were good in all cases with the exception of one type 1 endoprosthetic leak. The treatment of chronic post-traumatic aneurysms of the descending thoracic aorta gives excellent early and late results, justifying wide operative indications. The wish to avoid use of a prosthesis in young patients with a long life expectancy should give preference to conventional surgical techniques which, providing distal aortic perfusion is employed, allow direct suture of three quarters of cases. Endovascular treatment is reserved only for "poor surgical risks".

Polarized porcine trophoblastic cell lines spontaneously secrete interferon-gamma

Following the demonstration of high levels of interferon-gamma (IFN-gamma) synthesis by the pig trophectoderm around implantation, an adequate experimental system was established so as to study the regulation of endogenous IFN-gamma gene. Several stable cell lines have been isolated from Day 14 and 15 pig trophoblast, that could withstand indefinite growth when cultured on collagen-coated supports. Since no feeder cells were used for culture, and cell lines could be successfully cloned, these lines represent the first pure porcine trophoblastic (TB) cell lines isolated so far. These cells were shown to exhibit most differentiation markers of epithelial cells and in addition to express the porcine trophectoderm-specific antigen SN1-38. The TB cell line A (TBA) was characterized in more details upon culture on microporous filters, where a high apico-basal polarity could be obtained. In those conditions, a transient and acute interferon-gamma secretion was detected only in the apical medium. Moreover, the two trophoblast-specific mRNA of 1.3 and 1.4 kb that have been described in the blastocyst collected in vivo were shown to be synchronously transcribed. This polarized synthesis and secretion of IFN-gamma was correlated with the acquisition of maximal levels of electric resistance of TBA monolayers on filters, and was not observed on the same cells cultured on plastic. This differentiation was maintained over 30 passages, demonstrating that the induction of IFN-gamma secretion by pig conceptus is not maternally controlled. This cellular model will be of prime importance for studies on the developmental regulation of the IFN-gamma gene, and more generally for studies on relationship between secretion and polarity in transporting epithelia.

Directed evolution and Phenomics screening of new biocatalysts

Biodiversity screening and directed evolution are two fruitful complementary approaches for the discovery and design of novel biocatalysts. A new technology for directed evolution, L-Shuffling, has been designed and patented by Proteus. L-Shuffling technology offers several competitive advantages over other technologies including (i) directed evolution of large genes: L-Shuffling" means "Large-Shuffling"; (ii) high fidelity recombination and (iii) Control over location and frequency of recombination. The thousands of new recombinants generated by L-Shuffling can be further screened for their biochemical characteristics using Phenomics. Phenomics is a proprietary functional HTS technology designed and patented by Proteus for the screening of natural biodiversity as well as biodiversity generated by combinatorial biology. Phenomics is a function to gene structure approach which provides an alternative to genomics and proteomics. The traditional limits of expression libraries are thereby circumvented especially those related to cytotoxic products in usual or specific surrogate hosts. The quality of the answer given by the screening is directed dependent on the quality of the question asked. Thanks to a new substrates synthesis technology named CLIPS-O, the company can design highly specific molecules simulating the chemical structure and energetic state of the industrial substrates. The whole process of novel biocatalysts discovery has been automated using commercially available high throughput robotics.

[Evaluation of a new sequence of magnetic resonance cholangio-pancreatography in thick cut and one shot acquisition]

OBJECTIVES

To assess the accuracy and reproducibility of a new magnetic resonance cholangiopancreatography sequence (MRCP), using long echo time and "single shot" acquisition (providing high-contrast thick slices: 20 mm or more), in the morphological analysis of the biliary tree and pancreatic ducts.

METHODS

Fifty four patients with biliary and/or pancreatic disease were investigated with MRCP "single shot" thick slices. Biliary ducts were explored with MRCP "single shot", coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Natives pictures were reviewed by three independent radiologists, from three different institutions. MRCP results were compared with reference examinations in 54 cases (direct biligraphy methods: 54, CT scan: 11, endoscopic ultrasonography: 6, surgery: 6).

RESULTS

For detection of bile duct dilatation, the agreement of MRCP "single shot" thick slices was more than 96% (Kappa > 0.92) and the inter-observer agreement was excellent (Kappa=0.92). For detection of biliary tree and/or pancreatic duct obstruction, MRCP "single shot" thick slice sensitivity was above 89% and specificity was 75%. The malignant nature of the lesions was determined with a sensitivity of 100% and a specificity of 92%. MRCP "single shot" thick slices could not differentiate pancreatic carcinomas from distal main bile duct cholangiocarcinomas. MRCP "single shot" thick slices did not detect small stones ( 3 mm) of the common bile duct.

CONCLUSION

The excellent sensitivity, specificity and inter-observer agreement of MRCP "single shot" thick slices can be used to limit invasive imaging methods in the diagnosis of extrahepatic cholestasis.

Induction of porcine cytokine mRNA expression after DNA immunization and pseudorabies virus infection

Injection of plasmid DNA encoding pseudorabies virus (PRV) glycoprotein into pig muscle has been shown to result in protective immunity against lethal infection. Here, pigs were vaccinated by a single coinjection of three plasmids encoding PRV glycoproteins gB, gC, and gD, with plasmid expressing porcine granulocytemacrophage colony-stimulating factor (GM-CSF) or porcine interferon-alpha (IFN-alpha). DNA immunization induced a primary T cell-mediated response characterized by low rates of IFN-gamma, interleukin-2 (IL-2), and IL4 mRNA in peripheral blood mononuclear cells (PBMC). Very low rates of PRV-specific IgG1 and the absence of IgG2 were obtained. Codelivery of plasmid expressing GM-CSF or IFN-alpha had no effect on cytokine mRNA expression or on B cell response. After a high virulent challenge, high levels of cytokine mRNA, mainly IFN-gamma, and high secondary antibody (Ab) response were induced in all DNA-vaccinated pigs. Codelivery of GMCSF gene significantly increased both Th immune response (i.e., IFN-gamma and IL-4 mRNA expression) and clinical protection but had no effect on secondary B immune response. Codelivery of IFN-alpha gene had no beneficial effect on secondary T and B cell immune responses.

Ketogenic diet for the treatment of refractory epilepsy in children: A systematic review of efficacy

OBJECTIVES

To systematically review and synthesize the available evidence on the efficacy of the ketogenic diet in reducing seizure frequency for children with refractory epilepsy.

DATA SOURCES

Medline searches were performed using the keywords epilepsy/therapy, dietary therapy, and epilepsy, and the text word ketogenic diet. The Cochrane Library of clinical trials was searched using the term ketogenic diet. Bibliographies of recent review articles and relevant primary research reports, as well as Current Contents were reviewed for additional relevant citations.

STUDY SELECTION

Studies were selected for inclusion in the review that reported the reduction of seizure frequency following treatment with the ketogenic diet in children with refractory epilepsy. The outcome measures used were the percentage of patients with: 1) complete elimination of seizures, 2) >90% reduction in seizures, and 3) >50% reduction in seizures.

RESULTS

The evidence consists entirely of uncontrolled studies. Of 11 studies identified for this review, 9 are retrospective series of patients from a single institution. Two studies are prospective, 1 of which is a multicenter trial. The results of these studies are consistent in showing that some children benefit from the ketogenic diet, demonstrated by a significant reduction in seizure frequency. Estimates of the rates of improvement by combined analysis (confidence profile method) are complete cessation of all seizures in 16% of children (95% confidence interval [CI]: 11.0-21.7); a greater than 90% reduction in seizures in 32% (95% CI: 25.3-39.8); and a greater than 50% reduction in seizures in 56% (95% CI: 41.2-69.7). It is unlikely that this degree of benefit can result from a placebo response and/or spontaneous remission.

CONCLUSIONS

Although controlled trials are lacking, the evidence is sufficient to determine that the ketogenic diet is efficacious in reducing seizure frequency in children with refractory epilepsy.

Analytical and clinical performance of a detergent-based homogeneous LDL-cholesterol assay: a multicenter evaluation

BACKGROUND

LDL-cholesterol (LDL-C) concentrations currently are determined in most clinical laboratories using the Friedewald calculation. This approach has several limitations and may not always meet the current total error recommendation in LDL-C measurement of </=12% established by the National Cholesterol Education Program.

METHODS

In a multicenter study, we evaluated the analytical and clinical performance of a homogeneous LDL-C assay (LDL-C(Roche); Roche Diagnostics, Indianapolis, IN) in a comparison with a beta-quantification method.

RESULTS

This direct assay correlated highly with a beta-quantification method (r = 0.968; y = 1.037x - 95.8 mg/L; n = 355; 95% confidence intervals, 1.011-1.063 for the slope and -129.5 to 62.0 mg/L for the y-intercept) and met the current total error requirement. The assay was not affected significantly by concentrations of hemoglobin up to 6000 mg/L or bilirubin up to 500 mg/L. However, a negative bias of 10% was seen when triglyceride concentrations exceeded 10 000 mg/L. At the medical decision cut-point range, the LDL-C(Roche) assay showed positive predictive values of 91-100% and negative predictive values of 80-99%. Furthermore, the clinical utility of the assay seemed unaffected in samples obtained postprandially.

CONCLUSIONS

The homogeneous LDL-C(Roche) assay meets the currently established analytical performance goals and may be useful for the diagnosis and management of hyperlipidemic patients.

A new liquid homogeneous assay for HDL cholesterol determination evaluated in seven laboratories in Europe and the United States

We evaluated a new liquid homogeneous assay for the direct measurement of high density lipoprotein cholesterol (HDL-C Plus) in seven laboratories. The assay includes two reagents which can be readily used in most available clinical chemistry analyzers. The total CVs of the new method were below 4.6% and the bias in relation to the designated comparison method was below 3.9%. The total error ranged between 4 to 7%. HDL-C values determined by this method were in good agreement with those obtained by the old homogeneous assay using lyophilized reagents, and other homogeneous and precipitation assays (0.944 < r < 0.996). The assay was linear up to at least 3.89 mmol/l HDL-C. Hemoglobin did not interfere, whereas in icteric samples slight deviations were observed. Lipemia up to 11.3 to 22.6 mmol/l triglycerides did not interfere with this homogeneous HDL-C assay. In samples of patients with paraproteinemia, discrepant results were seen. This liquid homogeneous HDL-C assay was easy to handle and produced similar results in all laboratories participating in this study. This method will enable clinical laboratories to reliably measure HDL-C for risk assessment of coronary heart disease.

Screening for undetected mental disorders in high utilizers of primary care services

OBJECTIVE

To define the prevalence and detection rates of mental disorders among high utilizers as compared with typical utilizers, and to examine the effect of case-mix adjustment on these parameters.

DESIGN

Cross-sectional study.

SETTING

General internal medicine outpatient clinic associated with an urban, academic medical center.

PATIENTS

From patients attending a general medicine clinic, 304 were selected randomly in three utilization groups, defined by number of clinic visits: (1) high utilizers; (2) case-mix adjusted high utilizers; and (3) typical utilizers (control patients).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The presence of any mental disorder was ascertained by the PRIME-MD screening instrument. Chart review on all patients was performed to ascertain mental disorders detected by primary care physicians. The prevalence of mood disorders was markedly higher in high utilizers (29%) than in adjusted high utilizers (15%) or controls (10%) (p <.001). Anxiety disorders were slightly, but not statistically, more prevalent in the group adjusted for case mix (16%) than in other high utilizers (12%) or controls (9%). Alcoholism was significantly more prevalent in controls (12%) than in adjusted (6%) or other high utilizers (3%) (p <.03). The discrepancy in detection rates between PRIME-MD and chart review for any mental disorder was less for high utilizers (37% vs 31%) as compared with adjusted high utilizers (31% vs 11%) or controls (24% vs 8%).

CONCLUSIONS

Mood disorders are associated with a high overall burden of illness, while anxiety disorders are more predominant among outliers after case-mix adjustment. Detection rates differ substantially by utilization pattern. Screening efforts can be more appropriately targeted with knowledge of these patterns.

Lymphoproliferative disorders after renal transplantation: role of medical imaging

Post-transplantation lymphoproliferative disorders (PTLD) are a complication of immunosuppressed transplant recipients, and their incidence is reported to be 20-120 times greater than the rate in the general population. After kidney transplantation, PTLD more likely arise within the renal transplant fossa. Radiological patterns of these forms are presented and discussed, according to a review of the literature, and illustrated by cases from our institution. Ultrasound plays an essential role in the early diagnosis of PTLD by detecting a urinary obstruction associated with adenopathy or an ill-defined mass not previously seen. However, in the case of an inconclusive US examination, CT or MRI should be performed to confirm the presence of a mass. Both techniques are useful in evaluating the extension of the process within the transplantation fossa; MRI seems more accurate and can be used for the follow-up, especially after reduction in immunosuppressive therapy without transplant removal.

Predicting in-hospital mortality of patients receiving cardiopulmonary resuscitation: unit-weighted MultiODA for binary data

Widely used, linear classification functions may be derived on the basis of several different statistical paradigms. Since, regardless of choice, analysis generally yields an equation with unwieldy intercept and attribute coefficients, researchers often construct simpler scoring schemes based on unit weights. Accordingly, for applications involving entirely binary data, we discuss a simple procedure for obtaining unit-weighted (that is, we restrict attribute coefficients to the values of 0, 1 or -1) MultiODA functions that explicitly maximize classification accuracy in the training sample. We illustrate this with an application involving prediction of in-hospital mortality of patients receiving cardiopulmonary resuscitation. In training analysis of 88 patients, unit-weighted MultiODA outperformed prior scoring schemes and logistic regression analysis. Unit-weighted MultiODA also yielded superior hold-out (cross-generalizability) validity for an independent sample of 26 patients.

Heart failure between 1986 and 1994: temporal trends in drug-prescribing practices, hospital readmissions, and survival at an academic medical center

Since 1987, publications in widely circulated medical journals have reported improved survival and lower hospital readmission rates when patients with heart failure and systolic dysfunction are treated with angiotensin-converting enzyme (ACE) inhibitors. We describe changes in ACE inhibitor use among patients hospitalized with heart failure between 1986 and 1993. Simultaneous trends in readmissions and survival rates are reported. Subjects were 612 consecutive patients hospitalized with a principal diagnosis of heart failure at an academic medical center during the period of Sept. 1, 1986, to Dec. 31, 1987 (interval I) or during the period Aug. 1, 1992, to Nov. 30, 1993 (interval II). Medical records were reviewed for 434 patients, consisting of all patients hospitalized with heart failure during interval II and a randomly selected 50% subset of patients hospitalized during interval I. Among 145 patients with systolic dysfunction whose medical records were reviewed, ACE inhibitor prescriptions significantly increased between interval I and interval II (43% vs 71%, p < 0.01, odds ratio 3.22, 95% confidence interval 1.62 to 6.42). Prescriptions of ACE inhibitors combined with digoxin and a diuretic also increased (37% vs 56%, p = 0.02, odds ratio 2.22, 95% confidence interval 1.14 to 4.32). Among all 612 patients, 6-month heart failure readmission rates increased from 13% to 21% (p = 0.02, odds ratio 1.79, 95% confidence interval 1.10 to 2.82). There was no significant change in survival rate between interval I and interval II, however, survival rate was marginally significantly improved among patients with systolic dysfunction. Our results suggest that drug-prescribing practices have significantly changed between 1986 and 1993. The absence of observed improvement in outcomes may result from changes in hospital admission criteria for heart failure.

Systolic function, readmission rates, and survival among consecutively hospitalized patients with congestive heart failure

We sought to describe the relation between left ventricular systolic function and rates of hospital readmission and survival among consecutively hospitalized patients with congestive heart failure. Medical records were reviewed for these patients at an academic medical center between Jan. 1, 1992, and Dec. 31, 1993. Left ventricular systolic function assessments performed within 6 months before discharge were used to classify left ventricular systolic function. Hospital readmission rates and survival through Dec. 31, 1994, were compared between patients with systolic dysfunction and those with preserved systolic function. Among 412 patients hospitalized with a primary diagnosis of congestive heart failure, 224 had undergone a left ventricular function assessment during the 6 months before hospital discharge. In-hospital mortality and readmission rates were higher among patients without a recent assessment of left ventricular systolic function. Of patients with systolic dysfunction, 55% versus 41% of patients with preserved systolic function were either readmitted or had an emergency room visit within 6 months after discharge (p = 0.06). At 27 months' follow-up, cumulative survival probabilities were 65% for patients with preserved systolic function, 65% for patients with systolic dysfunction, and 60% for patients without a left ventricular systolic function assessment (p = 0.24). Patients without a recent left ventricular systolic function assessment have significantly higher hospital readmission rates than patients with a recent systolic function assessment. Among hospitalized patients, mortality rates are comparable between patients with systolic dysfunction and those with preserved systolic function. However, patients with heart failure with systolic dysfunction may have higher readmission rates.

A new Object Request Broker architecture in implementing a medical picture retrieval system

This paper describes the approach we used to implement the world wide web user interface of MediPict, a medical picture retrieval system. The best software architecture seemed to be the three-tier client/server architecture using Objects Request Brokers (ORB) which appears to have many benefits. Although CORBA appears to be the standard ORB, we found it more adequate to develop a different approach. This new ORB resolves many of CORBA's weaknesses (non coherent types, need of a static IDL, maintenance difficulties) by using the same language on the top and middleware tiers.

Atypical spI interferon binds on porcine cells to a major component of type I interferon receptor

The short porcine type I interferon (spI IFN), encoded by a gene physiologically expressed by the pig embryonic trophoblast during implantation, represents the first member of a novel family type I IFN. Binding and cross-linking experiments were carried out to characterize its cellular receptor. On porcine kidney cells, specific binding of 125I-spI IFN could be displaced significantly by spI IFN, rpIFN-alpha 1, and rhIFN-alpha 1, but not by rhIFN-alpha 2a or by rpIFN-gamma. On the other hand, all these type I IFNs but not rpIFN-gamma were capable of displacing bound 32P-hIFN-alpha A-P1 on these cells. Cross-linking data show that the specific 120 kD complex formed with these two radiolabeled ligands was displaceable by an excess of both spI IFN and rpIFN-alpha 1. These results provide primary evidence that spI IFN shares at least the major binding subunit of type I IFN receptor on porcine cells. On human WISH cells, 125I-spI IFN did not form any complex, nor did spI IFN affect cross-linking complexes of 32P-hIFN-alpha A-P1 on these cells, unlike rpIFN-alpha 1. The lack of antiviral and antiproliferative effects of spI IFN on human cells is primarily a result of its inability to recognize human type I IFN receptor.

Alcohol consumption among HIV-infected patients

This prospective, cohort study analyzed the prevalence of alcoholism and patterns of alcohol intake over time in a cohort of HIV-infected patients, predominantly homosexual/bisexual men. One hundred eleven HIV-positive subjects were recruited from a comprehensive HIV clinic associated with a large Midwestern university hospital. Each participant completed the Michigan Alcoholism Screening Test (MAST) survey and a standardized quantity-frequency questionnaire on alcohol intake at enrollment. The quantity-frequency scale was repeated every six months for a total of 30 months. Forty-five of the 111 subjects (41%) met the criteria for alcoholism, as defined by a MAST score 5 or higher. There was a significant decrease in alcohol consumption over time, from 6.4 drinks/week in the initial time period to 3.9 drinks/week by the final time period (p < 0.001).

Atypical porcine type I interferon. Biochemical and biological characterization of the recombinant protein expressed in insect cells

A recombinant baculovirus was designed to express short porcine type I interferon (spI interferon), a novel and atypical type I interferon that was recently described as the product of a gene transcribed in pig trophoblast at the time of implantation in the uterus [Lefèvre, F. & Boulay, V.C. (1993) J. Biol. Chem. 268, 19,760-19,768]. The recombinant protein, secreted into the culture medium of Sf9 cells at 3 days post infection (60,000 IU/ml), was purified by ion-exchange and reverse-phase HPLC. N-terminal sequencing confirmed the predicted signal peptide cleavage site and therefore the size of the mature protein (149 amino acids), the shortest of all reported type I interferons. Purified spI interferon, with a specific antiviral activity using Madin-Darby bovine kidney cells of 3.7 x 10(7) IU/mg, is an N-glycosylated monomer of 19 kDa that possesses several physicochemical characteristics of interferons: (a) disulfide bonds are necessary for bioactivity; spI interferon is thermolabile, stable at pH 2, and able to renature after complete denaturation (1% 2-mercaptoethanol, 1% SDS, and 5 M urea); (b) the carbohydrate chain is not essential for bioactivity since no loss of antiviral activity is observed following complete deglycosylation. In this study, antiviral and anti-proliferation activities of spI interferon in cell culture were compared with those of other interferons, especially with porcine type 1 interferon-alpha. A major difference with porcine type 1 interferon-alpha was that spI interferon was not active on human cells in either test, and it was relatively more active on pig cells compared to bovine cells than porcine type 1 interferon-alpha. Serological cross-neutralization results obtained with anti-(spI interferon) serum confirmed that several members of interferon families are not antigenically related to spI interferon, in agreement with previous observations; this provides further evidence that spI interferon could represent a new family of type I interferon.

A GTP-binding protein modulates a Ca2+ pump present in reticulocyte endocytic vesicles

Rat reticulocytes were used to prepare endocytic vesicles to study calcium fluxes across the endosomal membrane. We used 45Ca2+, and found that endocytic vesicles from reticulocytes present a Ca(2+)-ATPase that pumps Ca2+ into the lumen of vesicles. This activity was sensitive to vanadate and the calmodulin antagonists: trifluoperazine and calmidazolium. Western blot analysis using a monoclonal antibody evidenced that Ca(2+)-ATPase present in reticulocyte endocytic vesicles is probably the same as the erythrocyte Ca2+ pump. Ca2+ pump activity was shown to be partially inhibited by GTP gamma S. Moreover, mastoparan and benzalkonium chloride, both activators of heterotrimeric G proteins, were found to decrease 45Ca2+ uptake by endocytic vesicles. These results suggest the involvement of a trimeric G protein in the modulation of Ca(2+)-ATPase.

Changes in study design, gender issues, and other characteristics of clinical research published in three major medical journals from 1971 to 1991

OBJECTIVE

To examine trends in study design and other characteristics of original research published in JAMA, Lancet, and the New England Journal of Medicine (NEJM) between 1971 and 1991.

DESIGN

A retrospective cross-sectional study of original clinical research published in JAMA, Lancet, and NEJM during 1971, 1981, and 1991.

MEASUREMENTS

Four hundred forty-four articles were independently reviewed by at least two investigators and classified according to study design and other preselected study characteristics. Changes over time were analyzed by chi-square tests for categorical variables and analysis of variance for continuous variables.

MAIN RESULTS

Clinical results doubled, from 17% of all articles in 1971 to 35% in 1991 (p < 0.004), while case series decreased from 30% to 4% (p < 0.0001). Of 118 clinical trials, randomized controlled trials increased from 31% to 76% (p < 0.003) and nonrandomized controlled trials decreased from 42% to 8% (p < 0.002). Multicenter studies increased from 10% to 39% (p < 0.0001) and the prevalence of health services research increased from none in 1971 to 12% in 1991 (p < 0.001). The proportion of the studies explicitly excluding women from the subject population decreased from 11% in 1971 to 3% in 1991 (p < 0.03). In 1991 7% of the studies were composed entirely of men subjects, while only 0.7% of the studies were specific to men's health. Twelve percent of the studies in 1991 were specific to women's health. Between 1971 and 1991 there was no change in the prevalence of women first authors or studies addressing women's or minorities' health issues.

CONCLUSIONS

Several important changes in clinical research studies published in JAMA, Lancet, and NEJM have taken place between 1971 and 1991. Clinical trials have increased in frequency, largely replacing studies containing ten or fewer subjects. Health services research has increased in prevalence, reflecting growing interest in studies addressing the delivery of health care. Our data support the hypothesis that exclusion of women from clinical research studies is an important contributor to the paucity of data concerning women's health.

ST segment depression detected by continuous electrocardiography in patients with acute ischemic stroke or transient ischemic attack

BACKGROUND AND PURPOSE

Forty percent of patients with a history of ischemic stroke or transient ischemic attack (TIA) have concomitant coronary artery disease. ST segment depression, detected by continuous electrocardiography, is associated with increased cardiac morbidity and mortality in patients with known coronary artery disease. While electrocardiographic changes have been associated with acute stroke, the etiology and significance of these changes remain unclear. In this pilot study we report the prevalence of ST segment depression and ventricular arrhythmias in patients with acute ischemic stroke or TIA monitored by continuous electrocardiography. Clinical predictors of ST segment depression and ventricular arrhythmia are also identified.

METHODS

Consecutive patients presenting with acute ischemic stroke or TIA were enrolled within 72 hours of hospital admission and monitored by continuous electrocardiography for 48 hours. The electrocardiographic results were analyzed for periods of ST segment depression and ventricular arrhythmias.

RESULTS

Of 51 patients with ischemic stroke or TIA, 15 (29%) had episodes of ST segment depression (95% confidence interval, 15% to 43%), and 18 (35%) had ventricular arrhythmias (95% confidence interval, 21% to 49%). In logistic regression analysis, increasing age (P < .02) and a left-sided neurological event (P < .01) were significant predictors of ST segment depression. Increasing numbers of atherosclerotic risk factors, a history of cardiac disease, and increasing or decreasing mean arterial pressure were not predictive of ST segment depression.

CONCLUSIONS

Patients with acute ischemic stroke or TIA have a 29% prevalence of ST segment depression within the first 5 days after their event. In comparison, the prevalence of ST depression is 2.5% to 8% in asymptomatic adults and 43% to 60% in patients with symptomatic coronary artery disease. The association of ST segment depression with left-sided neurological events suggests that the electrocardiographic changes are in part neurologically mediated. Further study is necessary to better define the brain-heart interaction and to determine whether ST segment depression in patients with ischemic stroke or TIA reflects underlying coronary artery disease.

Predicting survival from in-hospital CPR: meta-analysis and validation of a prediction model

OBJECTIVE

To better clarify patient factors that predict survival from in-hospital cardiopulmonary resuscitation (CPR), using two methods: 1) meta-analysis and 2) validation of a prediction model, the pre-arrest morbidity (PAM) index.

DESIGN

Meta-analysis of previously published studies by standard techniques. Retrospective chart review of validation sample.

SETTING

University-affiliated teaching hospital.

PATIENTS/PARTICIPANTS

Meta-analytic sample of 21 previous studies from 1965-1989. The validation sample consisted of all patients surviving resuscitation from the authors' hospital during the period September 1986 to January 1991. A matched sample of patients who did not survive from the same time period was used as the comparison group.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The strongest negative predictors of survival, by meta-analysis, were renal failure (r = 0.088, p < 0.0002), cancer (r = 0.08, p < 0.0002), and age more than 60 years (r = 0.063, p < 0.006). Sepsis (r = 0.046, p < 0.02), recent cerebrovascular accident (CVA) (r = 0.038, p < 0.04), and congestive heart failure (CHF) class III/IV (r = 0.036, p < 0.05) were weaker negative predictors. Presence of acute myocardial infarction (AMI) was a significant positive predictor of survival (r = 0.15, p < 0.0001). The PAM score was highly predictive of survival in a logistic regression model (p < 0.0003, R2 = 9.6%). No patient who survived to discharge had a PAM score higher than 8.

CONCLUSION

Meta-analysis reveals that the most significant negative predictors of survival from CPR are renal failure, cancer, and age more than 60 years, while AMI is a significant positive predictor. The PAM index is a useful method of stratifying probability of survival from CPR, especially for those patients with high PAM scores, who have essentially no chance of survival.

Use of the Rand Structured Implicit Review Instrument for Quality of Care Assessment

The Rand Structured Implicit Review Instrument is a 27-item instrument that rates process quality of care for patients with five common illnesses. This study reports on the use of this instrument for hospitalized patients with long lengths of stay. A total of 120 medical records were reviewed by multiple physician reviewers for patients discharged with congestive heart failure, acute myocardial infarction, and pneumonia. Mean inter-rater reliability was assessed for a subsample of six records by kappa score. A multiple regression analysis was used to estimate the relationship between process ratings for the quality of documentation, assessment, monitoring, and therapy and overall quality of care scores, controlled for physician judgments about patients' prognosis and selected patient characteristics. Each reviewer also evaluated the instrument. Mean kappa for trichotomized ratings of quality of care was 0.50. The majority of all quality of care ratings were in the good or very good range (77.5%). The full regression model, including process subscale quality ratings, prognostic items, and patient characteristics, accounted for 38% of the total variance in the quality of care ratings. Items measuring the quality of assessment (p < 0.0001), therapy (p < 0.02) and monitoring (p < 0.01) were significant. Physicians accepted the use of such a form moderately well. The Rand quality of care form shows consistency in rating overall quality of care and individual dimensions of quality. Achieving a high level of inter-rater reliability is difficult with implicit review. By focusing on specific areas of potentially deficient care, structured review instruments can improve clinical quality improvement efforts.

Ribosomal DNA studies in poplars: Populus deltoides, P. nigra, P. trichocarpa, P. maximowiczii, and P. alba

The nuclear rDNA physical maps of Populus nigra, P. deltoides, P. trichocarpa, P. maximowiczii, and P. alba have been built up for the restriction enzymes EcoRI, EcoRV, BamHI, PstI, and SacI. There is no HindIII site. A large variability appeared between the species in the intergenic spacer mainly for EcoRI and PstI. For several clones of each species two to three major unit types coexist in the genome, while several minor units as well as length variant units or new unit types have been found. The variability between the species is due to different major unit types, while the variability between clones in one species is due to the minor unit types. Every species carries several rDNA unit types either different in size (variable length unit) or variable in restriction sites (variable unit types). Four thousands copies of rDNA units were found in P. nigra, P. deltoides, and P. maximowiczii. The clones belonging to the same species carry the same major unit types but are different in their minor variable length units or minor unit types. The hybrid clones carry the sum of the major unit types of the two parental species. These facts suggested the existence of three rDNA loci. The combination of one enzyme EcoRI and one probe (flax entire rDNA unit) allowed to easily recognize each of the five species. Conversely, we detected the presence of rDNA fragments characteristic to P. deltoides in some clones belonging to P. nigra. We conclude that these clones are likely to have a hybridization in their stands but without observable phenotypic consequences. This technique will be used to verify the purity of each P. nigra candidate clone before exploiting it in a breeding or propagation program.Key words: Populus, nuclear rDNA, intergenic spacer variation, introgression.

Iatrogenic complications in high-risk, elderly patients

BACKGROUND

This study explores the quality improvement potential of reviewing care for long-stay, elderly medicine service patients hospitalized for congestive heart failure, acute myocardial infarction, or pneumonia at a large Midwestern teaching hospital.

METHODS

Medical records were reviewed for 120 patients aged 65 years or older who were discharged between January 1987 and June 1989, with hospital stays of 15 days or longer. Patients' severity of illness on admission was rated using the Medicare Mortality Predictor System; process quality of care was rated using a structured implicit review form for judging several dimensions of clinical assessment and decision making. Serious complications were coded by etiology and type and judged as possibly or probably preventable. Logistic regression was used to identify risk factors for iatrogenic events; multiple regression was used to assess potential outcome bias in ratings of overall quality of care.

RESULTS

Of 120 medical records reviewed, 70 (58.3%) suffered at least one iatrogenic complication. Forty-three patients (35.8%) suffered an iatrogenic complication rated as potentially preventable. Significant predictors of all iatrogenic complications were quality ratings of initial physician assessment, patients' inability to walk unassisted, and low Glasgow Coma Score. For potentially preventable complications, quality ratings for physician documentation of functional status were also significant. Ratings for overall quality of care were not significantly influenced by the mere presence of death or complications.

CONCLUSIONS

Iatrogenic complications are likely to be an extremely common experience for elderly medicine service patients with long lengths of stay. A significant portion of these complications may be potentially preventable with closer attention to initial assessment and documentation of patients' functional status.