Validation of the Intelligent Cognitive Assessment System (ICAS) for stroke survivors.

PRIMARY OBJECTIVE: To investigate the internal consistency, test-re-test reliability of an Intelligent Cognitive Assessment System (ICAS) and its optimal cut-off score for stroke patients with or without cognitive impairment. METHOD: A prospective cohort study design was adopted. Sixty-six post-stroke patients of aged 60 or above were recruited. They were screened by the Chinese version of Mini Mental State Examination (MMSE-CV) and assessed by the Intelligent Cognitive Assessment System (ICAS) consisting of 65 testing items which could be presented at a level according to stroke patient's response. It was administered to examine the internal consistency and test-re-test reliability (by repeating within a 7-day interval). The optimal cut-off score to screen stroke patients having cognitive impairment was determined by the receiver operating characteristics (ROC) curve. RESULTS: The internal consistency of the ICAS (Cronbach's alpha = 0.878) and its test-re-test reliability (rho = 0.789; p < 0.001) were demonstrated. The cut-off score for the ICAS to determine cognitive impairment was found to be 3.02, with a sensitivity of 80.5% and specificity of 96%. CONCLUSION: Preliminary results suggested that ICAS was a valid and reliable cognitive screening tool for stroke survivors. The ICAS can be further developed by studying its norms for stroke patients. It is also programmable for potential application to different countries by changing ICAS to other language versions and including other culturally relevant content.

Power analysis for biomarkers in mussels for use in coastal pollution monitoring.

Data from literature on neutral red retention time (NRRT) in lysosomes, micronucleus (MN) frequency and condition index (CI) in mussel Mytilus, especially Mytilus edulis and Mytilus galloprovincialis, were re-analyzed to ascertain their statistical power in detecting a minimum 20% spatial/temporal change in field studies. Results showed that CI largely displayed higher statistical power (>90%) than lysosomal NRRT and MN frequency (<50%), suggesting that data from the latter two biomarkers may lead to erroneous conclusions if sample size is inadequate. Samples of green-lipped mussel Perna viridis were also analyzed in Hong Kong. To achieve statistically valid power, the optimal sample sizes for monitoring lysosomal NRRT, MN frequency, CI and gonosomatic index (GSI) were determined as >or=34, >or=90, >or=16 and >or=29, respectively. Natural variability of lysosomal NRRT and MN frequency was significantly greater than CI and/or GSI in mussels, rejecting the general belief in the greater variability of higher-tiered hierarchical biomarkers.

Influences of ammonia-nitrogen and dissolved oxygen on lysosomal integrity in green-lipped mussel Perna viridis: laboratory evaluation and field validation in Victoria Harbour, Hong Kong.

Lysosomal integrity in mussels has been applied as a biomarker to detect the pollution of trace organics and metals in the natural environments. However, few studies have examined the effects of water quality on the response of lysosomal integrity, in particular total ammonia-nitrogen (TAN) and dissolved oxygen (DO). This study demonstrated that high level of TAN (2.0mg/l) and low DO (2.5mg O(2)/l) could significantly reduce the lysosomal integrity in green-lipped mussel Perna viridis, respectively by 33% and 38%, whereas the mussel lysosomal integrity decreased by 70% in the combined treatment of TAN and low DO under laboratory conditions after one week. The mussel lysosomal integrity of all treatment groups could return to the control level after a three week recovery period. In the field validation in Victoria Harbour, Hong Kong during an one-year study period, lysosomal integrity in P. viridis identified the cleanest site east to the harbour, where the lowest TAN and highest DO concentrations were found. While lysosomal integrity in mussels seemed not affected by seasonal changes, approximately 40% of the variation of this biomarker could be attributable to the changes in TAN and DO in seawater. In conclusion, the response of the mussel lysosomal integrity can be confounded by both TAN and DO prevailing in the natural environments and thus caution must be exercised in relating the observed changes in lysosomal integrity to any specific pollutant in coastal water quality monitoring studies.

Lung volumes before and after lung volume reduction surgery: quantitative CT analysis.

The volume and severity of pulmonary emphysema in individual lungs were measured by means of quantitative computed tomography (CT) studies in 28 patients (14 women, 14 men, median age 65 yr) who underwent either bilateral (n = 15) or unilateral (n = 13) lung volume reduction surgery (LVRS). Spirometric, total body plethysmographic, and CT data (at TLC and RV) were correlated before and after LVRS. Lung volumes determined by CT correlated well with volumes obtained by total body plethysmography (p < 0.0001). For individual lungs after LVRS, CT-derived mean lung capacity decreased 13% and residual volume 20% (p < 0.00001 for each), while mean total functional lung volume (TFLV, defined as the volume of lung with CT attenuation greater than -910 Hounsfield units) increased 9% (p < 0.01), and the mean ratio of the air space to tissue space volume (V(AS)/V(TS)) decreased more at RV (23%) than at TLC (14%) (p < 0.0005 for each). In contrast, unilateral LVRS did not affect exhalation from the unoperated lung (2% reduction in RV, p = NS). The magnitude of the postoperative response (CT-derived TLC, RV, TFLV, V(AS)/V(TS)) of each operated lung was comparable for unilateral and bilateral LVRS. Thus, a lung's response to LVRS was independent from that of the contralateral lung. Moreover, postoperative alterations in TFLV and FEV1 correlated significantly (r = 0.80, p < 0.0001), which suggests that the expansion of functioning tissue may contribute to the mechanism by which LVRS palliates airway obstruction.

A simple endogenous growth model with endogenous fertility: indeterminacy and uniqueness.

PIP: Considerable literature exists upon the effect of population growth upon per capita income growth. Among the reported studies, Brander and Dowrick (1994) try to explain the large variation across countries in per capita income growth. The authors explore the possibility that even with little differences in fertility rates, different countries may experience disparate growth performances solely due to the emergence of indeterminate equilibria, which could push them into different equilibrium trajectories. The equilibrium dynamics and indeterminacy of equilibria in an endogenous growth model with endogenous fertility choice are studied. The authors characterize the conditions which give rise to a unique equilibrium as well as multiple equilibria. When a unique equilibrium exists, it will be globally determinate, and when multiple equilibria arise, indeterminacy occurs. Two equilibria were found to occur, one associated with high fertility and low growth and the other with low fertility and high growth. A parameterized example is presented to assess the empirical feasibility of results. The validity of the neo-Malthusian relation between fertility and growth is then re-examined. The authors also explore the relationship between growth and welfare, and compare different balanced growth equilibria in terms of their lifetime attained utility.^ieng

Population growth and economic growth: a reconsideration.

PIP: The relationship between population growth and development has long been a controversial topic in the economic development literature. Early work by Hoover and Coale and more recent work by Blanchet suggest that high fertility suppresses per capita income growth. However, recent work by Kelley and Srinivasan are ambivalent about such a neo-Malthusian relationship between population growth and economic growth. The authors examine these conflicting positions. They emphasize that the rates of both population growth and income growth are endogenous variables within a general equilibrium framework. An endogenous growth model with endogenous fertility is then developed. It is found that when all exogenous variables are controlled for, there exists an inverse relation between population growth and economic growth. However, when some exogenous factors change, such as an improvement in technological progress, the relation becomes ambiguous. This suggests that the conflicting findings in the literature may be because of the presence of substantial heterogeneity in unobserved variables across countries and over time in cross-country panel data sets.^ieng

Intralobar pulmonary sequestration and mediastinal bronchogenic cyst.

A patient with a bronchogenic cyst and intralobar pulmonary sequestration is presented. Chest radiography showed a posterior mediastinal mass and a computed tomographic scan of the chest revealed, in addition, an abnormality suggestive of pulmonary sequestration. This was confirmed by an aortogram. It is important to be aware of the coexistence of these anomalies to make a diagnosis preoperatively.

Optimal population size and endogenous growth.

"Many applications in economics require the selection of an objective function which enables the comparison of allocations involving different population sizes. The two most commonly used criteria are the Benthamite and the Millian welfare functions, also known as classical and average utilitarianism, respectively. The former maximizes total utility of the society and thus represents individuals, while the latter maximizes average utility and so represents generations. Edgeworth (1925) was the first to conjecture, that the Benthamite principle leads to a larger population size and a lower standard of living.... The purpose of this paper is to examine Edgeworth's conjecture in an endogenous growth framework in which there are interactions between output and population growth rates. It is shown that, under conditions that ensure an optimum, the Benthamite criterion leads to smaller population and higher output growth rates than the Millian."

Emphysematous pyelonephritis simulating intestinal obstruction and pneumatosis intestinalis.

A case of emphysematous pyelonephritis is reported. The initially puzzling plain abdominal radiographs simulated intestinal obstruction and pneumatosis intestinalis. Resolution was later confirmed sonographically.

Sonographic recognition of pneumatosis intestinalis and portal gas in an 11-months-old infant--case report.

Sonography was performed on an 11-month old infant who presented with intestinal obstruction. Pneumatosis intestinalis and portal venous gas were detected in addition to dilated small bowel loops. Preoperative diagnosis of small bowel gangrene was made which was proven at operation.

CT findings in transdiaphragmatic empyema necessitatis due to tuberculosis.

A case of transdiaphragmatic empyema necessitatis due to tuberculosis presented clinically as a subcutaneous mass in the posteroinferior right chest. Imaging studies revealed a 12 cm diameter suprahepatic mass contiguous with thickened and calcified right pleura. Even in the preantibiotic era, such a presentation of empyema necessitatis was very unusual.

Relationship of functional residual capacity to static pulmonary mechanics in chronic obstructive pulmonary disease.

Static pulmonary mechanics may not be the sole determinant of the functional residual capacity (FRC) in the chronic obstructive pulmonary diseases (COPD). To assess the relationship of FRC to pulmonary mechanics, pulmonary function tests such as spirometry, lung volumes, maximum expiratory flow volume curves, and single-breath diffusing capacity were related to compliance measurements in 65 patients with stable COPD. Compliance studies were examined over the range of tidal volume and at maximum lung inflation. The results showed that there was a poor correlation between the degree of hyperinflation at FRC and static compliance in the tidal range. However, there was a highly significant correlation between FRC and static lung mechanics at maximum lung inflation, as well as between FRC and diffusing capacity. Thus, in patients with stable COPD, FRC is a useful guide to static recoil properties of the lung as assessed at maximum lung inflation. Lung compliance measurement in tidal range may not reflect this relationship. An increase in FRC remains a useful index of pulmonary emphysema, even in the presence of chronic airway disease.