Probing unfolded acoustic phonons with X rays

Ultrafast laser excitation of an InGaAs/InAlAs superlattice (SL) creates coherent folded acoustic phonons that subsequently leak into the bulk (InP) substrate. Upon transmission, the phonons become "unfolded" into bulk modes and acquire a wave vector much larger than that of the light. We show that time-resolved x-ray diffraction is sensitive to this large-wave vector excitation in the substrate. Comparison with dynamical diffraction simulations of propagating strain supports our interpretation.

Observation of surface-avoiding waves: a new class of extended states in periodic media

Coherent time-domain optical experiments on GaAs-AlAs superlattices reveal the existence of an unusually long-lived acoustic mode at approximately 0.6 THz which couples weakly to the environment by evading the sample boundaries. Classical as well as quantum states that steer clear of surfaces are generally shown to occur in the spectrum of periodic structures, for most boundary conditions. These surface-avoiding waves are associated with frequencies outside forbidden gaps and wave vectors in the vicinity of the center and edge of the Brillouin zone. Possible consequences for surface science and resonant-cavity applications are discussed.

Generation and propagation of a picosecond acoustic pulse at a buried interface: time-resolved x-ray diffraction measurements

We report on the propagation of coherent acoustic wave packets in (001) surface oriented Al0.3Ga0.7As/GaAs heterostructure, generated through localized femtosecond photoexcitation of the GaAs. Transient structural changes in both the substrate and film are measured with picosecond time-resolved x-ray diffraction. The data indicate an elastic response consisting of unipolar compression pulses of a few hundred picosecond duration traveling along [001] and [001] directions that are produced by predominately impulsive stress. The transmission and reflection of the strain pulses are in agreement with an acoustic mismatch model of the heterostructure and free-space interfaces.

Assessment: transcranial Doppler ultrasonography: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

OBJECTIVE

To review the use of transcranial Doppler ultrasonography (TCD) and transcranial color-coded sonography (TCCS) for diagnosis.

METHODS

The authors searched the literature for evidence of 1) if TCD provides useful information in specific clinical settings; 2) if using this information improves clinical decision making, as reflected by improved patient outcomes; and 3) if TCD is preferable to other diagnostic tests in these clinical situations.

RESULTS

TCD is of established value in the screening of children aged 2 to 16 years with sickle cell disease for stroke risk (Type A, Class I) and the detection and monitoring of angiographic vasospasm after spontaneous subarachnoid hemorrhage (Type A, Class I to II). TCD and TCCS provide important information and may have value for detection of intracranial steno-occlusive disease (Type B, Class II to III), vasomotor reactivity testing (Type B, Class II to III), detection of cerebral circulatory arrest/brain death (Type A, Class II), monitoring carotid endarterectomy (Type B, Class II to III), monitoring cerebral thrombolysis (Type B, Class II to III), and monitoring coronary artery bypass graft operations (Type B to C, Class II to III). Contrast-enhanced TCD/TCCS can also provide useful information in right-to-left cardiac/extracardiac shunts (Type A, Class II), intracranial occlusive disease (Type B, Class II to IV), and hemorrhagic cerebrovascular disease (Type B, Class II to IV), although other techniques may be preferable in these settings.

Continuous Quality Improvement in Dialysis Units: Basic Tools

Physicians and allied health professionals are expected to understand and participate in the assessment and improvement of the quality of care delivered to patients in end-stage renal disease (ESRD) treatment centers. Participating in the quality improvement process will bring clinicians into contact with special knowledge and skills drawn from the areas of statistical process control and industrial engineering. Some of the more frequently encountered of these concepts and tools are described.

Improving Serum Albumin Levels in Hemodialysis Patients by a Continuous Quality Improvement Project

Protein nutrition and serum albumins predict present and future mortality and morbidity. The North East Albuquerque Dialysis Center undertook a quality improvement project to improve serum albumin levels in hemodialysis patients. The dialysis facility's quality assurance team evolved into a continuous quality improvement team just before this project. The timeline and steps in this evolution are presented. The continuous quality improvement project process analysis, interventions, and outcome rates are also described. The project has resulted in a rate of less than or equal to 10% of hemodialysis patients with serum albumins less than 3.4 for the past 3 years.

Reduced anterior cingulate gyrus volume correlates with executive dysfunction in men with first-episode schizophrenia

Although frontal lobe structural and functional abnormalities have been identified in schizophrenia, their relationship remains elusive. Because the frontal lobes are both structurally and functionally heterogeneous, it is possible that some measures of frontal lobe structure may not have accurately identified relevant frontal lobe subregions. The authors hypothesized that the volumes of two dorsal, 'archicortical' subregions (i.e. superior frontal gyrus and anterior cingulate gyrus), but not a ventral, 'paleocortical' subregion (i.e. orbital frontal region) would be significantly and selectively correlated with executive and motor dysfunction in patients with schizophrenia as previously reported for the anterior hippocampal region. Volumes of these frontal lobe subregions were measured from magnetic resonance images based on sulcal anatomy in 20 men and 15 women with first-episode schizophrenia. All patients completed a comprehensive neuropsychological test battery while clinically stabilized that encompassed six domains of functioning: attention, executive, motor, visuospatial, memory and language. Findings indicated that reduced anterior cingulate gyrus volume was significantly correlated with worse executive functioning in men; among women, there were no significant correlations. Among men, anterior cingulate gyrus volume was significantly more strongly correlated with executive functioning than with attention, visuospatial, memory, language and general intellectual functioning. Neither executive nor motor functioning was significantly more strongly correlated with the dorsal 'archicortical' volumes than with orbital frontal volume. These findings suggest a link between executive deficits and dysfunction of the dorsal 'archicortical' system and implicate sex differences in their relationship in first-episode schizophrenia.

Neuropsychology of first-episode schizophrenia: initial characterization and clinical correlates

OBJECTIVE

Neuropsychological impairments are well documented in schizophrenia and are important targets of treatment. Information about the severity and pattern of deficits after treatment for the first psychotic episode and about relationships between these deficits and syndromal characteristics remains limited.

METHOD

Comprehensive neuropsychological assessments including 41 individual tests were given to 94 patients with first-episode schizophrenia after initial stabilization of psychosis and to a comparison group of 36 healthy volunteers. Profiles of neuropsychological deficits and the relationship of deficits to sex and handedness were examined. Correlations of neuropsychological deficit with a broad range of historical and clinical characteristics, including outcome, were explored.

RESULTS

Patients had a large generalized neuropsychological deficit (1.5 standard deviations compared to healthy volunteers). Patients also had, superimposed on the generalized deficit, subtle relative deficits (less than 0.5 standard deviation compared to their own average profile) in memory and executive functions. Learning/memory dysfunction best distinguished patients from healthy individuals; after accounting for this difference, only motor deficits further distinguished the groups. Patients with higher neuropsychological ability had only memory deficits, and patients with lower ability had both memory and executive deficits. No sex differences were observed beyond the normal advantage for men in motor speed. Dextral patients had less severe generalized deficit. Severity of residual symptoms was associated with greater generalized deficit. Executive and attentional deficits were most linked to global functional impairment and poor outcome.

CONCLUSIONS

The results document a large generalized deficit, and more subtle differential deficits, in clinically stabilized first-episode patients. Learning/memory deficits were observed even in patients with less severe generalized deficit, but the pattern was unlike the amnestic syndrome and probably reflects different mechanisms. Executive and attentional deficits marked the more severely disabled patients, and may portend relatively poor outcome. Failure to develop typical patterns of cerebral dominance may increase the risk for greater generalized deficit.

Proline in vasoactive peptides: consequences for peptide hydrolysis in the lung

To examine the hypothesis that trans isomers of bradykinin and [Gly6]bradykinin are preferentially hydrolyzed by lung peptidases, we studied the fractional inactivation of these peptides in the perfused rat lung using a bioassay after a single-pass bolus injection and high-performance liquid chromatography after lung recirculation. In the bioassay studies, when the peptides passed through the lung, 25.6-fold more bradykinin or 7-fold more [Gly6]bradykinin was required to elicit a contraction equivalent to that produced when the peptides did not pass through the lung. In the recirculation studies, hydrolysis progress curves with rapid and slow phases were observed, with a higher fraction of bradykinin than [Gly6]bradykinin hydrolyzed in the rapid phase. Cyclophilin increased the hydrolysis rate during the slow phase for both peptides. Kinetic analysis indicated that the slowly hydrolyzed peptide fraction, presumably the cis fraction, was 0.13 for bradykinin and 0.43 for [Gly6]bradykinin with cis-trans isomerization rate constants of 0.074 and 0.049 s-1, respectively, consistent with published nuclear magnetic resonance studies.

Continuous quality improvement in ESRD: the role of networks, the United States Renal Data System, and facility-specific reports

End-stage renal disease (ESRD) outcome improvement involves many different private and governmental entities. Networks have fulfilled a pivotal role in ESRD quality improvement by facilitating the change from quality assurance (QA) to continuous quality improvement (CQI) methodology, providing the collection and dissemination of outcome measures to facilities and developing quality improvement projects (QIPs) that interface directly with facilities. Improving outcomes in hemodialysis is generally limited to adequacy of hemodialysis and anemia management. Opportunities in peritoneal dialysis, nutrition, vascular access, and quality-of-life outcomes persist. Interaction between facilities and Medical Review Boards (MRBs) using workshops, site visits, and facility report cards can provide continuing ESRD outcome improvement. Every facility has unique people, procedures, and equipment producing their processes of care. Therefore, a certain amount of autonomy is required to encompass individual variation. Quality improvement methodology, although less rigorous than traditional outcome research, provides efficient and effective intervention when a rapid response is required to improve clinical outcomes. The two methods are not mutually exclusive but require distinct methodology to accomplish.

Meta-analysis of symptom factors in schizophrenia

Factor and correlational analyses have been used to characterize symptom dimensions in schizophrenia, though they have yielded divergent models. This study used meta-analysis of published work to determine the number and composition of symptom dimensions. Principal components analysis of data from 10 empirical studies (pooled n = 896) yielded three factors, 'positive', 'negative' and 'conceptual disorganization'. The findings suggest that a three-factor solution is a relatively stable outcome of studies assessing these symptoms in chronic patients, and that some symptoms (alogia, attentional impairment) are less likely to load uniquely on a single factor.

An analysis of the determinants of urinary urea and creatinine clearance in patients on continuous peritoneal dialysis

The relative contribution of urinary volume (UV) and urine-to-plasma concentration ratios for urea (U/PUr) and creatinine (U/PCr) to urinary Kt/V urea (Kt/VU) and urinary uncorrected creatinine clearance (CCrU), respectively, was studied by simple and multiple linear regression analysis in 236 urea kinetic studies and 233 creatinine kinetic studies performed in 135 patients on continuous peritoneal dialysis (CPD). The following simple regressions were obtained: Kt/VU = 0.09 + 0.72 (UV), r = 0.75; Kt/VU = -0.01 + 0.11 (U/PUr), r = 0.55; CCrU = 12.06 + 56.46 + 46.46 (UV), r = 0.62; CCrU = 3.51 + 3.40 (U/PCr), r = 0.58. All r values were significant (p < 0.001). According to these regressions, a loss of 0.2 L/24 hours in UV leads to a loss of 0.15 weekly in Kt/VU and 11.3 L/1.73 m2 weekly in corrected CCrU (approximately 8 L/1.73 m2 weekly in corrected CCrU). By multiple linear regression, (1) Kt/VU = -0.38 + 0.70 (UV) + 0.10 (U/PUr). Standardized coefficients were 0.72 for UV and 0.51 for U/PUr (2) CCrU = -33.36 + 59.83 (UV) + 3.63 (U/PCr). Standardized coefficients were 0.65 for UV and 0.61 for U/PCr. UV is the most important determinant of both urea and creatinine urinary clearances in CPD patients. The contribution of the U/P ratios to the urinary clearances is important, but less than that of UV. The primary dependence of urinary clearances on UV allows the use of UV, which can be easily monitored by patients, as a first approximation index of changing residual renal function in CPD.

Serum albumin in continuous peritoneal dialysis: its predictors and relationship to urea clearance

We investigated the predictors of serum albumin and the relationship between serum albumin and urea kinetic indices in continuous peritoneal dialysis (CPD). In a training set (TS) of 143 urea kinetic studies performed in 92 CPD patients, stepwise logistic regression identified high/high-average peritoneal solute transport, diabetes, advanced age and high daily drain volume normalized by body water as predictors of low serum albumin (< 35 g/liter). This analysis was then substantiated in a validation set (VS) of 187 kinetic studies performed in another 102 CPD patients. The calculated area under the receiver operating characteristic (ROC) curve by this logistic regression model was 0.782 (95% CI, 0.745 to 0.819). Logistic regression was repeated in the TS using only the first kinetic study from each patient, and it identified high/high-average peritoneal solute transport, diabetes, and advanced age as predictors of low albumin. Using only the first kinetic study from each patient in the VS, the second logistic regression model calculated an area under the ROC curve equal to 0.850 (95% CI, 0.810 to 0.890). The relative risk (RR) of serum albumin < 35 g/liter was computed for all kinetic studies after combining the TS and the VS and using non-diabetic CPD subjects aged < or = 61 years with low/low average peritoneal solute transport as the reference group. The RR with only one risk factor present ranged from 1.076 (age > 61 years) to 6.792 (high/high-average transport). The RR with two risk factors present ranged from 5.200 to 9.729. The RR with all three risk factors present was 9.100 (95% CI, range 3.923 to 21.111). A subset of 37 CPD patients had a second urea kinetic study 8 +/- 5 months after an increase in the amount of dialysis due to low urea clearance and/or uremic symptoms. The weekly KT/V urea increased from 1.40 +/- 0.24 to 2.10 +/- 0.31 after the increase in the CPD dose. With the increase in dialysis, the protein catabolic rate increased substantially; however, the mean serum albumin remained stable (from 33.9 +/- 4.6 to 33.3 +/- 6.2 g/liter; decrease 18; increase 15; same 4). In comparison to the subjects who had a decrease in serum albumin after the increase in KT/V, those with the increase in serum albumin were younger (44.2 +/- 11.2 vs. 54.3 +/- 16.2 years, P = 0.044) and had a higher serum urea after the increase in the dose of CPD (22.4 +/- 7.8 vs. 17.0 +/- 6.0 mmol/liter, P = 0.037). We conclude that the major predictors of low serum albumin in CPD are advanced age, diabetes, and high/high-average peritoneal solute transport, but not urea kinetic studies. An increase in the dose of dialysis does not cause a consistent rise in serum albumin in underdialyzed CPD subjects. However, a subset of younger patients may be able to increase their serum albumin in response to the increase in KT/V.

Discriminability of the Wisconsin Card Sorting Test using the standardization sample

The four neurological patient groups and the normals from the Wisconsin Card Sorting Test (WCST) standardization sample were used to examine the discriminability of the WCST's indices. Results reveal consistent differentiation of normals from the patient groups on all WCST variables, with classification rates averaging 71% accuracy. However, patient groups with frontal, diffuse, and nonfrontal lesions were not consistently discriminable from each other. The results suggest that the WCST is most usefully conceptualized as a measure of executive abilities that involves the frontal lobes, but should not be considered solely as a marker of isolated frontal lobe pathology.

Results of a computerized screening of stroke patients for unjustified hospital stay

BACKGROUND AND PURPOSE

Effective methods to monitor length of stay can help reduce unnecessary hospital stay without adversely affecting the quality of care. In this study a clinical algorithm for assessing unjustified hospital stay in stroke patients was computerized and tested.

METHODS

An algorithm was developed by the authors to estimate the number of medically justified and unjustified hospital days for patients admitted with a primary diagnosis of ischemic stroke. Data for the algorithm were obtained from 177 stroke patients from an acute-care teaching hospital. The performance of the algorithm was evaluated on a subset of 46 patients by comparing the number of medically unjustified hospital days determined by the algorithm with the consensus determination of two neurologists.

RESULTS

The algorithm classified 68% of the 177 patients as having some unjustified hospital days and 41% of all hospital days as unjustified. With the neurologists as the gold standard, the sensitivity of the algorithm was .89 and the specificity was .91. The correlation between the number of unjustified days determined by the algorithm and the neurologists was .76.

CONCLUSIONS

There is considerable unjustified length of stay for stroke patients. Physicians can develop simple clinical algorithms for detecting unjustified hospital stay in stroke patients that provide a reasonable approximation of complex clinical judgment.

Creatinine clearance in continuous peritoneal dialysis: dialysis dose required for a minimal acceptable level

OBJECTIVES

To identify the most advantageous formula for estimating creatinine clearance (CCr) and to establish a dose of dialysis that will ensure minimal acceptable levels of creatinine clearance in patients on continuous peritoneal dialysis (CPD).

DESIGN

Analysis of all CCr studies performed in CPD patients over 40 months.

SETTING

All four dialysis units following CPD patients in one city. One dialysis unit is government-owned, one is university-affiliated, and two are community based.

PARTICIPANTS

One hundred and ninety-four patients representing almost the entire CPD population in Albuquerque.

INTERVENTIONS

Creatinine and urea clearance studies were performed in 24-hour urine and drained dialysate samples. Creatinine clearance (peritoneal plus urinary) was normalized to either 1.73 m2 body surface area (CCr) or body water estimated by the Watson formulas (KT/VCr). CCr and KT/VCr were either corrected by averaging urinary creatinine and urea clearances or were not corrected. Two dialysis units were designated as the training set (92 patients, 143 clearance studies) and the other two units as the validation set (102 patients, 181 clearance studies).

MAIN OUTCOME MEASURES

Minimal acceptable creatinine clearance levels were determined in the training set by computing the creatinine clearance value corresponding to 1.70 weekly KT/V urea by linear regression. Logistic regression models predicting low creatinine clearance were developed in the training set and were tested in the validation set.

RESULTS

The following weekly creatinine clearance values corresponded to 1.70 KT/V urea: corrected CCr 52.0 L/1.73 m2, uncorrected CCr 54.4 L/1.73 m2, corrected KT/VCr 1.46, uncorrected KT/VCr 1.53. Logistic regression identified as predictors of low creatinine clearance low daily urine volume (UV) and low daily dialysate drain volume/body water (DV/V) for all four creatinine clearance formulas, plus low/low-average peritoneal solute transport (only for uncorrected CCr) and serum creatinine (for both KT/VCr formulas). In the validation set, the predictive models produced an area under the receiver operating characteristic (ROC) curve between 0.835 and 0.919 indicating very good predictive accuracy. For corrected CCr and anuria, the regression model produced a minimal normalized drain volume (DV/V) value consistent with minimal acceptable CCr equal to 0.305 L/L per 24 hours. This DV/V cutoff detected low corrected CCR in validation set anuric subjects (n = 55) with a sensitivity of 85% and a specificity of 71%. For uncorrected CCR and anuria, DV/V cutoffs were 0.273 L/L per 24 hours (high/high-average peritoneal solute transport) and 0.420 L/L per 24 hours (low/low-average transport). Sensitivity and specificity of these cutoffs in validation set anuric subjects were 87% and 85%, plus 86% and 33%, respectively.

CONCLUSIONS

The uncorrected CCr appears to be the most advantageous creatinine clearance formula in CPD, because it allows the use of peritoneal solute transport type in the calculation of the minimal required normalized drain volume. The minimal acceptable uncorrected CCr is 54.4 L/1.73 m2 weekly. To achieve this uncorrected CCr in anuria, the required minimal normalized drain volume is 0.273 L per liter of body water daily if peritoneal solute transport is high or high-average and around 0.420 L per liter of body water daily if peritoneal solute transport is low or low-average. The required total daily drain volume is computed by multiplying the required normalized drain volume by body water.

Protein Catabolic Rate in PaStients on Continuous Peritoneal Dialysis

Protein catabolic rate (PCR) and PCR normalized to standard weight (PCRN) are important indices of nutrition in patients on continuous peritoneal dialysis. The purpose of this study was to test whether urea clearance is among the predictors of PCR and PCRN in a multivariate analysis. Stepwise logistic regression was used to develop separate models for low PCR and low PCRN on a set of 143 urea kinetic studies in 92 patients on continuous peritoneal dialysis. The regression models were tested on an independent sample of 189 urea kinetic studies in 102 patients on continuous peritoneal dialysis by deriving the area under a receiver operating characteristic curve. In the derivation set, low serum urea, high serum creatinine, low urine and dialysate drain volumes, and low body surface area were identified as predictors of PCR < or = 50 g daily. The area under the receiver operating characteristic curve in the validation set was 0.930 (95% confidence interval: 0.915-0.945). Low serum urea, male gender, high body mass index and low urea fractional clearance (KT/V) were predictors of PCRN < or = 0.80 g/kg daily. The receiver operating characteristic area for this model was 0.948 (95% confidence interval: 0.926-0.970). Logistic regression analysis was repeated twice after adding urea nitrogen excretion normalized to standard weight (UNEN) as a candidate variable. This process identified low UNEN, male gender, and obesity as the predictors of low PCRN, and low UNEN, male gender, low urine volume, low drain volume normalized by body water, and high serum albumin as predictors of low KT/V urea. The authors conclude that PCR and PCRN can be predicted by models that incorporate serum azotemic indices, body size and composition, and direct or indirect measurements of urea clearance. Small body size and lean body composition predict low PCR but high PCRN values. Both PCRN and KT/V urea are predicted by UNEN. Multivariate analysis cannot, therefore, rule out the hypothesis that PCRN and KT/V are linked mathematically.

The minimal dose of dialysis required for a target KT/V in continuous peritoneal dialysis

This study attempted to define the minimal dose of dialysis needed to produce a target KT/V in continuous peritoneal dialysis (CPD). In a training set of 143 clearance studies performed in 92 CPD patients, logistic regression identified low urine volume (UV) and low dialysate drain volume normalized by body water (DV/V) as predictors of weekly KT/V urea < or = 1.70. Solution of the regression equation with UV fixed at 0.00 1/24 h and at different probabilities of low KT/V provided a series of minimal DV/V values consistent with weekly KT/V > or = 1.70 in anuria. The accuracy of the logistic regression model and of the DV/V cut-offs was tested in a validation set (VS) of 189 urea kinetic studies performed in another 102 CPD patients. In the VS, the area under the Receiver Operating Characteristic curve generated by the regression model was 0.832 (95% Confidence Interval: 0.798-0.866). The DV/V cut-off value of 0.301 per 24 h, calculated by solving the regression model at p = 0.442 and with UV = 0, identified studies with weekly KT/V < 1.70 with a sensitivity of 89.3% and a specificity of 78.1% in anuric VS subjects (n = 60). Use of only the first urea kinetic study from each patient did not modify the predictors of KT/V or the cut-off values derived from solution of the regression model. The DV/V cut-off of 0.324 per 24 h, derived from the logistic regression model predicting KT/V < or = 1.90, identified KT/V < 1.90 in VS anuric subjects with a sensitivity of 94.3% and a specificity of 81.0%. Low UV and DV/V predict low KT/V urea in CPD. Prescribed 24 h exchange volume in anuric CPD subjects should be calculated to produce DV/V values exceeding 0.301 1/24 h per 1 body water for a KT/V of 1.70 and 0.324 1/24 h per 1 body water for a target weekly KT/V of 1.90.

Modifiability of neuropsychological dysfunction in schizophrenia

Schizophrenia is often characterized by compromised neuropsychological functioning, especially on tasks sensitive to frontal and temporohippocampal functions but the extent to which cognitive dysfunction can be modified in schizophrenics remains unclear. Twenty-four inpatient schizophrenics and 24 intellectually and demographically matched, inpatient mood-disordered controls were randomly assigned to one of two conditions. Subjects assigned to the cued condition received instructional cues on measures of visual and semantic memory, executive function, and constructional ability. Subjects in the standard condition performed the same neuropsychological measures without cues. The present study revealed some degree of plasticity of neurobehavioral function in schizophrenia.

Comparison of indices of premorbid function in schizophrenia

There has been a resurgence of interest in the area of premorbid functioning in schizophrenia as it provides clues to onset and etiology. Most studies rely on retrospective estimates of premorbid status that are incomplete, such as the Premorbid Adjustment Scale (PAS). Even prospective high-risk studies are hampered by the narrow range of premorbid functions assessed and are thus unable to answer crucial questions related to onset of illness. This study was undertaken to assess the relationship between several indices of premorbid functioning. Sixty four in-patients with schizophrenia were assessed at medication-free baseline and post-treatment with BPRS and SANS. PAS scores were derived from all available sources. Premorbid cognitive ability was estimated by the mean of WAIS-R Vocabulary and Information subscale scores. Estimated premorbid IQ was obtained using a demographic regression formula. Years of education and predicted VIQ, PIQ, and FSIQ were found to correlate with estimated premorbid cognitive ability. Predicted VIQ, PIQ, and FSIQ were associated with years of education and PAS childhood, early and late adolescence, and general scores. Each estimate of premorbid ability demonstrated a different pattern of association with clinical ratings, symptom change, and outcome. The results suggest that education, PAS, predicted IQ, and WAIS-R estimates of premorbid cognitive ability assess different but overlapping areas of pre-morbid functioning.

Cross-sectional analysis of erythropoietin use in CPD: its relation to azotemic index clearances

The association between the use of erythropoietin and urea or creatinine clearance was studied in two populations on continuous peritoneal dialysis (CPD) residing either at an altitude of 1600 m (n = 194) or at sea level (n = 108). Among peritoneal and total KT/V urea and creatinine clearance (CCr) indices, only total CCr was lower in the high altitude group receiving erythropoietin than in the corresponding group not receiving erythropoietin (68.0 +/- 34.9 vs 82.9 +/- 40.9 L/1.73 m2 weekly, p < 0.01). However, 24-hour urine volume and urinary KT/V urea and CCr were consistently lower in the groups receiving erythropoietin than in those not receiving erythropoietin. Total weekly KT/V urea < or = 1.70 and CCr < or = 52 L/1.73 m2 were considered indicators of inadequate CPD. Although the percent of patients receiving erythropoietin did not differ overall between groups with adequate and those with inadequate CPD, a trend towards more frequent use of erythropoietin was found in the sea level group with inadequate CCr versus the group with adequate CCr (28.2% vs 16.9%, p = 0.084). In CPD decreased renal function is associated with more frequent use of erythropoietin. Whether inadequate total urea or creatinine clearance is also associated with more frequent erythropoietin use requires further study.

Severity of illness measures derived from the Uniform Clinical Data Set (UCDSS)

The Health Care Financing Administration (HCFA) plans to use the Uniform Clinical Data Set System (UCDSS) to collect data on hospitalized Medicare patients. This study examined the value of UCDSS data for creating severity of illness measures. UCDSS data were obtained from a study hospital and from a national data set for patients with pneumonia (n = 528) and stroke (n = 565). Models to predict length of stay or an adverse event were derived for each condition using HCFA claims data alone, UCDSS data alone, and UCDSS data supplemented with additional information also abstracted from charts. The models were derived from one set of patients and validated on another. The R2 for predicting length of stay in the validation data for the UCDSS model was 0.29 for pneumonia and 0.19 for stroke compared to R2 values from the claims model of 0.09 for stroke and 0.06 for pneumonia. UCDSS models also were better than claims models for predicting adverse events. The best UCDSS models included International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and other information requiring clinical judgment, and were improved by adding more information on patient functional status. Some findings were more strongly associated with outcome for the study hospital than for the national data. These results suggest that UCDSS models will predict outcome much better than the claims based models currently used by HCFA for the analysis of hospitalization-related mortality; more functional status information should be added to UCDSS; and despite an extensive objective database, the most predictive UCDSS models require clinician-assigned diagnostic codes.

Comparison of Four Wisconsin Card Sorting Test Scoring Guides With Novice Raters

The utility of the Wisconsin Card Sorting Test (WCST) is predicated on the ability of its users to accurately administer and score the task. This study evaluated four different WCST scoring guides in an effort to determine the most reliable and accurate instructional set for use by individuals previously unfamiliar with scoring the WCST. The study targeted the scoring of perseverative responses, as this is the most difficult of the measures to learn. Novice raters using one of four methods (original manual alone, decision tree [key guide] with the original manual, written supplement with the original manual, and revised manual only) and expert raters each scored 20 technically difficult WCST protocols. The results demonstrated that novice raters who used the written supplement to score these difficult protocols were as reliable and accurate in scoring perseverative responses as the experts. Those who used either the original manual alone or the key guide with the manual were less reliable. Scoring perseverative responses with the revised manual's instructions was considerably more reliable and accurate than scoring with the original manual. However, scoring performance for perseverative responses with the revised manual did not achieve that of the novice raters using the written supplement. It is recommended that scoring accuracy for cognitive measures be empirically validated rather than assumed.

Factor structure of the negative symptom assessment

The factor structure of the Negative Symptom Assessment (NSA), a standardized negative symptoms rating scale, was systematically evaluated in a group of 223 inpatients with schizophrenia. Confirmatory factor analyses found that a six-factor model best described the NSA. More specifically, the domains of Communication, Emotion/Affect, Social Involvement, Motivation, Gross Cognition, and Retardation characterized the rating scale. This latent structure of the NSA is consistent with a multidimensional conceptualization of negative symptoms.

[Graft bone associated with hydroxyapatite and reconstructive plate as treatment in a case of mandibular osteomyelitis]

A case report of the mandibular osteomyelitis, after the deciduous tooth extraction at the age of five years. The patient was submitted to reconstructive inclusion graft bone and hydroxyapatite.

Validation of the 16-item Negative Symptom Assessment

The dimensional structure of the 16-item Negative Symptom Assessment (NSA-16) was validated in a sample of 223 unmedicated schizophrenic inpatients and cross-validated on an independent sample of 276 patients with schizophrenia. Using a confirmatory factor analytic procedure, a five factor model was found to best characterize the structure of this rating instrument. These factors include: Communication, Emotion/Affect, Social Involvement, Motivation, and Retardation. The latent structure of the NSA-16 is similar to the larger instrument from which it was derived. The findings provide support for a multidimensional model of negative symptoms in schizophrenia and offer a useful measure for their assessment.

Neuropsychological prediction of treatment efficacy and one-year outcome in schizophrenia

The present study was conducted to establish the degree of interrelationship between neuropsychological functioning in the acute phase of the schizophrenic illness, clinical measures of treatment response (positive and negative symptoms), and 1-year outcome. Nineteen SADS/RDC schizophrenic inpatients were clinically rated during a 2-week drug washout period and again following 4 weeks of neuroleptic treatment. The findings revealed that reduced attentional ability in the baseline phase significantly predicted the presence of higher residual negative symptoms following 4 weeks of treatment, while neurocognitive status was unrelated to positive symptom response. With respect to prediction of the 1-year outcome, poor functional status of this schizophrenic population was significantly associated with the presence of baseline memory dysfunction.

Effect of instructional cues on schizophrenic patients' performance on the Wisconsin Card Sorting Test

OBJECTIVE

Schizophrenic patients are particularly deficient on measures of executive functioning, notably the Wisconsin Card Sorting Test. This study was conducted to determine the efficacy of a cuing strategy in facilitating performance on this cognitive measure of the integrity of prefrontal brain structures and functioning.

METHOD

Twenty-four schizophrenic inpatients and 24 demographically matched inpatients with mood disorders were administered the Wisconsin Card Sorting Test either with instructional cues at the beginning of the task or with the standard administration procedure.

RESULTS

There was a significant benefit of cues for the patients with affective disorders as well as for the schizophrenic patients. The schizophrenic subjects in the uncued condition maintained poor but stable performance throughout the course of the task.

CONCLUSIONS

The study suggests that the deficit in executive functioning of schizophrenic patients may lie in the formation of concepts, not in their application.

Neuropsychological function and REM sleep in schizophrenic patients

To test the hypothesis that rapid eye movement (REM) sleep in schizophrenic patients is associated with cognitive function, we studied 18 schizophrenic inpatients by means of electroencephalograms taken during sleep in their own hospital beds after a minimum 2-wk medication withdrawal period. Patients underwent neuropsychological tests to measure memory function and other aspects of cognitive performance. REM sleep measures demonstrated positive and negative correlations with cognition and memory measures, depending on when REM occurred after sleep onset. Minutes of REM sleep and REM density in the first period correlated negatively with performance, while REM minutes occurring after the first REM period correlated positively with neuropsychological performance. Further work should test whether phasic REM sleep regulation at the beginning of the night plays a compensatory role for neuropsychological dysfunction in schizophrenics.

Longitudinal sensitivity of the Fuld cholinergic profile to Alzheimer's disease

The diagnostic sensitivity of a profile (Fuld, 1984) thought to mark cholinergic changes in Alzheimer's Disease (AD) was examined in a sample of 53 patients meeting criteria for AD on two occasions and in 19 patients for three occasions. The low obtained sensitivities of the Fuld profile (17%-26%) across testings is consistent with previous studies that used a single time point. The findings also revealed unstable positive and negative profiles over time. There were no performance differences on intellectual or memory measures when comparing subjects identified as positive or negative by the Fuld index. The results demonstrate that the index is insensitive to the dementing process and is a poor diagnostic marker for AD.

Very brief psychotherapy in the psychiatric consultation setting

Very brief psychotherapy has emerged as a unique treatment modality in recent years. The limited time frame dictates flexibility in the choice of therapeutic technique, but there exists a need for an assessment model to link specific technique with the clinical problem. An early psychotherapeutic formulation containing three parts is the central component of the assessment model: theoretical description of the problem, immediate goal, and intervention technique. Various theories of psychopathology and therapeutic techniques can be simultaneously applied to the clinical problem. Three cases illustrate the use of this model in a consultation/liaison setting.

Sensitivity of the Mini-Mental State Examination to frontal lobe dysfunction in normal aging

The present study examined the sensitivity of the Mini-Mental State Examination (MMSE) in detecting the frontal lobe dysfunction that occurs with normal aging. Eighty normal, independently living older adults in four age groupings from 50 to 89 were administered the MMSE along with three neurocognitive measures sensitive to frontal lobe functioning. Results revealed age-related cognitive decline on frontal lobe tasks that also was detected by the MMSE. These findings are noteworthy because the MMSE was intended as a measure of gross cognitive status rather than of frontal lobe functioning.

Measurement of depression and negative symptoms in schizophrenia

The validity of the Hamilton Depression Scale (HAM-D) as a measure of depressive symptomatology in schizophrenic patients is questionable since it was not developed for this purpose, nor has it been validated in a schizophrenic population. Accordingly, 80 schizophrenic inpatients were administered the HAM-D, the 18-item Brief Psychiatric Rating Scale (BPRS), and the Scale for the Assessment of Negative Symptoms (SANS) at drug-free baseline and after 4 weeks of neuroleptic treatment. The findings revealed that the HAM-D total score was nonspecific, while individual HAM-D subfactors provided a better index of various symptom complexes. The HAM-D contained a depressive factor that correlated strongly with the BPRS depression factor and a negative symptom factor that correlated strongly with the SANS and the BPRS negative symptom factor. These findings suggest the need to utilize specific assessment techniques rather than global measures when assessing depression in schizophrenia.

Hand gangrene in diabetic patients on chronic dialysis

To determine whether any potentially reversible variables are related to the development of hand gangrene in diabetic patients on dialysis, the authors compared 15 patients with hand gangrene (group A) to three control groups of diabetics on dialysis: 20 patients with foot gangrene (group B); 31 patients without gangrene of the extremities (group C); and 20 patients without hand arterial calcifications (group D). All patients in groups A-C had medial arterial calcifications of the hands. Group A patients started dialysis at an earlier age (p less than 0.05), were treated for end-stage renal disease (ESRD) for a longer time period (p less than 0.05), and had a lower mean serum albumin concentration during the dialysis period (p less than 0.05) than the patients in the control groups. Hand gangrene also appeared to be associated with the presence of a functioning arterio-venous fistula in the extremity with the gangrene, with loss of function of renal transplant, and with hyperaluminemia. Other variables, including serum parathormone, were not different for the four groups. Logistic regression showed that the following were risk factors for hand gangrene: hypoalbuminemia, long duration of ESRD treatment, hyperphosphatemia, high insulin dose, hypercholesterolemia, and hypoglycemia. In diabetics on dialysis, gangrene develops in hands with medial arterial calcifications, but does not correlate with measures of calcium or phosphorous metabolism. Predictors of hand gangrene include certain potentially reversible clinical and biochemical variables.

Endothelin induces a sustained rise in intracellular calcium in hippocampal astrocytes

We report that the endothelins, a newly described family of vasoactive peptides, have a profound effect on intracellular calcium levels of cultured rat hippocampal astrocytes that resembles the effect of endothelin (ET) on vascular smooth muscle cells (VSMCs) in many respects. The astrocyte's response has two components that can be distinguished by their extracellular calcium requirement and time course. Within seconds of application, ET induces a transient calcium spike that corresponds to a release of calcium from internal stores. The second component follows immediately, is dependent upon extracellular calcium, and maintains an elevated intracellular calcium level for many minutes. Sustained elevations of intracellular calcium can dramatically alter astrocyte morphology and induce cell division in many other cell types. ET may serve these functions, and thus form a communication link between blood vessels and neurons through astrocytes.

Stability of positive and negative symptom constructs during neuroleptic treatment in schizophrenia

To assess the structural stability of positive and negative symptom ratings, we rated 40 schizophrenic inpatients on the Brief Psychiatric Rating Scale (BPRS) and the Scale for the Assessment of Negative Symptoms (SANS) at medication-free baseline and after 4 weeks of neuroleptic treatment. Positive symptom variables consisted of six BPRS items, and the negative symptom variables consisted of the five SANS subscale global scores. On principal components analysis, a three-factor, oblique-rotated solution resulted, with a negative symptom factor, a positive symptom factor, and an unstable behavioral agitation factor. The pre- and posttreatment factor loading patterns were similar. The findings suggest that BPRS-positive symptom items and the SANS measure distinct clinical dimensions and that the construct is stable, as demonstrated by minimal structural change with time.

Experience-dependent cognitive recovery in alcoholics: a task component strategy

Visuospatial problem-solving deficits following chronic alcohol abuse may not readily recover spontaneously after drinking cessation but may reverse with appropriate environmental stimulation. To determine if such recovery in alcoholics under age 40 may be accelerated by training with components of an initially impaired task (Trails B), this study employed four groups of alcoholics (N = 53) and a group of matched controls (N = 13). Two alcoholic groups received two consecutive cognitive remediation sessions during the latter 2 weeks of a 1-month treatment program, and two groups of alcoholics received no remediation. Results confirmed that recovery of visuospatial problem-solving skills is facilitated by training with task components (experience-dependent recovery) while spontaneous recovery during the first month of abstinence is minimal for this task. These findings demonstrate the efficacy of cognitive remediation in reversing some alcohol-induced cognitive impairment and have important implications for improving alcohol treatment outcome and adaptive functioning.