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Anand Kumar

Publications and source records attributed to Anand Kumar.

At least 73 records · Page 4Linked to original sources
PubMed2004

Mistakes in medical ontologies: where do they come from and how can they be detected?

We present the details of a methodology for quality assurance in large medical terminologies and describe three algorithms that can help terminology developers and users to identify potential mistakes. The methodology is based in part on linguistic criteria and in part on logical and ontological principles governing sound classifications. We conclude by outlining the results of applying the methodology in the form of a taxonomy different types of errors and potential errors detected in SNOMED-CT.

Algorithms↗
PubMed2003

Magnetization transfer imaging and magnetic resonance spectroscopy of normal-appearing white matter in late-life major depression.

PURPOSE: To examine the relationships between the damaged macromolecular pool seen on magnetization transfer (MT) imaging and cerebral metabolic changes recorded by magnetic resonance spectroscopy (MRS), in frontal white and gray matter regions of late-life MDD patients. MATERIALS AND METHODS: MT imaging and MRS were performed on eight patients with late-life MDD and eight age-matched healthy controls. MT ratios were calculated using the on-resonance and off-resonance images. Correlations were computed between MT ratios and the ratios of several metabolites, including choline (Cho), myo-inositol (mI), N-acetylaspartate (NAA), and N-acetylaspartylglutamate (NAAG), to creatine (Cr). RESULTS: Statistically significant correlations were found in white matter between the MT ratios and mI/Cr (r = -0.90, N = 7, P = 0.016), and between the MT ratios and (NAA + NAAG)/Cr (r = -0.89, N = 8, P = 0.007). No significant correlations were found in gray matter or between the MT ratios and NAA/Cr or Cho/Cr in white matter. CONCLUSION: Changes in the white matter macromolecular protein pool, observed as reduced MT ratios, may be related to changes in the mI and the total NAA pools. These findings may have implications for the pathophysiology of late-life major depression.

Aged↗
PubMed2003

Neuropsychological deficits among patients with late-onset minor and major depression.

Cognitive ability of minor depressed patients (N=28), major depressed patients (N=26) and healthy elderly (N=38) was examined cross-sectionally to determine if cognitive abilities of patients with late-onset depression decrease with increasing severity of disease and if cognitive scores for minor depressed patients fall between those of healthy elderly and major depressed patients. A pooled within-group principal component analysis of cognitive test scores identified five components, three of which showed significant group differences. Verbal Recall and Maintenance of Set separated controls from major depressed patients and minor from major depressed patients. Executive Functioning separated controls from minor depressed patients, and Working Memory was borderline for separating controls from major depressed patients. The component representing Nonverbal Recognition was not statistically significant. Partial correlations controlling for age and education indicate that cognitive performance does decrease as severity of depression increases, and the magnitude of the change varies from a trend to a significant deficit depending on the cognitive domain. This decline in cognitive performance parallels a similar trend observed in neuroanatomical studies in which the volume of the frontal and temporal lobes decrease with increasing severity of depression.

Age of Onset↗
PubMed2003

Modular representation of the guideline text: an approach for maintaining and updating the content of medical education.

One of the principal challenges in the medical practice is the update of their knowledge. One of the prime roles of the Continuing Medical Education is to train the medical practitioners with the latest advances in health care, specialized to their needs. Online courses and classroom teaching with computer-based representations have become an established mode of delivering medical education. This paper deals with the modularized representation of a medical text concerning clinical practice guidelines. The proposed system takes into consideration the semantics of the Unified Medical Language System and is based upon the marking up and display of the knowledge using the XML and XSLT languages. This modularization of the concepts leads to the determination of the context of a portion or the whole document. Thus, after marking up using our system, the text components can be exchanged, modified or reconstructed, which, in turn, would help to maintain the updates in medical knowledge.

Artificial Intelligence↗
PubMed2003

Algorithmic evaluation of metabolic control and risk of severe hypoglycemia in type 1 and type 2 diabetes using self-monitoring blood glucose data.

The optimization of metabolic control in Type 1 and Type 2 diabetes mellitus (T1DM and T2DM, respectively) [i.e., the maintenance of near-normal hemoglobin A(1c) (HbA(1c)) without increasing the risk of hypoglycemia] could be enhanced by analysis of self-monitoring blood glucose (SMBG) data assessing complementary processes: exposure to hyperglycemia and hypoglycemia. We present algorithms that simultaneously estimate HbA(1)c and risk for significant hypoglycemia using 45-60 days of SMBG. The algorithms were developed using a primary data for 96 subjects with T1DM (n = 48) and T2DM, and were validated in an external data for 520 subjects with T1DM (n = 231) and T2DM. All subjects were on insulin. In the primary (external) data the estimation of HbA(1c) had absolute error of 0.5 (0.7) units of HbA(1c) and percent error of 6.8% (8.1%); 96% (96%) of all estimates were within 20% from reference HbA(1c). The SMBG-estimated value of HbA(1c) was closer to current reference HbA(1c) than a reference HbA(1c) value taken only 2-3 months ago. The results in T1DM and T2DM were similar. Linear model predicted future significant hypoglycemia (R(2) = 62%, p < 0.0001). The leading predictor was a previously introduced Low Blood Glucose Index, which alone had R(2) = 55%. Probability model assessed accurately the odds for future moderate/severe hypoglycemia (coefficients of determination 92%/94%). Four risk categories were identified; within moderate- and high-risk category, there was no difference between T1DM and T2DM in the occurrence of prospective significant hypoglycemia. SMBG data allow for accurate estimation of the two most important markers of metabolic control in T1DM and T2DM - HbA(1c) and risk for hypoglycemia.

Adult↗
PubMed2003

Septic shock, multiple organ failure, and acute respiratory distress syndrome.

In 1914, Schottmueller wrote "Septicemia is a state of microbial invasion from a portal of entry into the blood stream which causes signs of illness." In the last few decades, the evidence that sepsis results from an exaggerated systemic inflammatory host response induced by infecting organisms is compelling; inflammatory mediators are the key players in the pathogenesis of septic shock and multiorgan failure. Sepsis and its sequelae represent a continuum of clinical syndrome encompassing systemic inflammation, coagulopathy, and hemodynamic abnormalities. Severe sepsis and septic shock continue to be the major causes of morbidity and mortality in the United States; sepsis deaths currently match mortality from myocardial infarction. Despite significant advances in our understanding of the pathophysiology and technological innovations in the supportive management, mortality from septic shock remains excessive. After many disappointments with strategies to manipulate the inflammatory response, modulation of coagulation cascade to decrease sepsis mortality has become a clinical reality. This review will highlight and discuss recent advances in the pathophysiology and management of sepsis.

Anti-Bacterial Agents↗
PubMed2003

Persistent left superior vena cava: an intensivist's experience and review of the literature.

Persistent left superior vena cava is a relatively rare vascular anomaly. It is, however, the most common variation in the thoracic venous system. The anomaly is typically detected on chest x-ray after the placement of a pulmonary artery catheter or pacemaker leads. This report describes a case of persistent left superior vena cava detected after successful placement of a pulmonary artery catheter.

Catheterization, Swan-Ganz↗
PubMed2003

Combined treatment with methylphenidate and citalopram for accelerated response in the elderly: an open trial.

BACKGROUND: Accelerated antidepressant treatment response may be particularly beneficial for older patients, yet there are few data to inform clinical practice. We evaluated the potential of methylphenidate to accelerate antidepressant response to citalopram and the safety and tolerability of the combined treatment in patients with geriatric major depressive disorder. METHOD: We studied 11 elderly outpatients aged 70 years and older who were diagnosed with DSM-IV major depressive disorder in a 10-week, open-label, structured trial (July 2001-July 2002). Methylphenidate was tapered and discontinued during weeks 9 and 10. Response was defined as a Hamilton Rating Scale for Depression (HAM-D) score of less than 10. The daily dose of citalopram ranged between 20 and 40 mg, and the daily dose of methylphenidate ranged between 5 and 20 mg. RESULTS: Nine patients completed the study. Six patients met criteria for accelerated response (HAM-D score < 10 and Clinical Global Impressions-Improvement scale score of 1 or 2 by treatment day 14), and 2 more patients responded by week 3. One patient was a nonresponder. The mean (SD) citalopram dose for all subjects was 27.5 (10.3) mg and the mean (SD) methylphenidate dose was 12.2 (4.9) mg. The observed side effects were mild to moderate in severity and included sedation, nausea, anxiety, polyuria, dry mouth, and hypersalivation. CONCLUSION: Methylphenidate augmentation of citalopram may be a safe and viable strategy for accelerating antidepressant response in elderly depressed patients. The results of this open-label trial need to be confirmed in a placebo-controlled trial.

Aged↗
PubMed2003

Relating UMLS semantic types and task-based ontology to computer-interpretable clinical practice guidelines.

Medical knowledge in clinical practice guideline (GL) texts is the source of task-based computer-interpretable clinical guideline models (CIGMs). We have used Unified Medical Language System (UMLS) semantic types (STs) to understand the percentage of GL text which belongs to a particular ST. We also use UMLS semantic network together with the CIGM-specific ontology to derive a semantic meaning behind the GL text. In order to achieve this objective, we took nine GL texts from the National Guideline Clearinghouse (NGC) and marked up the text dealing with a particular ST. The STs we took into consideration were restricted taking into account the requirements of a task-based CIGM. We used DARPA Agent Markup Language and Ontology Inference Layer (DAML + OIL) to create the UMLS and CIGM specific semantic network. For the latter, as a bench test, we used the 1999 WHO-International Society of Hypertension Guidelines for the Management of Hypertension. We took into consideration the UMLS STs closest to the clinical tasks. The percentage of the GL text dealing with the ST "Health Care Activity" and subtypes "Laboratory Procedure", "Diagnostic Procedure" and "Therapeutic or Preventive Procedure" were measured. The parts of text belonging to other STs or comments were separated. A mapping of terms belonging to other STs was done to the STs under "HCA" for representation in DAML + OIL. As a result, we found that the three STs under "HCA" were the predominant STs present in the GL text. In cases where the terms of related STs existed, they were mapped into one of the three STs. The DAML + OIL representation was able to describe the hierarchy in task-based CIGMs. To conclude, we understood that the three STs could be used to represent the semantic network of the task-bases CIGMs. We identified some mapping operators which could be used for the mapping of other STs into these.

Humans↗
PubMed2002

Clinical review: Myocardial depression in sepsis and septic shock.

Myocardial dysfunction frequently accompanies severe sepsis and septic shock. Whereas myocardial depression was previously considered a preterminal event, it is now clear that cardiac dysfunction as evidenced by biventricular dilatation and reduced ejection fraction is present in most patients with severe sepsis and septic shock. Myocardial depression exists despite a fluid resuscitation-dependent hyperdynamic state that typically persists in septic shock patients until death or recovery. Cardiac function usually recovers within 7-10 days in survivors. Myocardial dysfunction does not appear to be due to myocardial hypoperfusion but due to circulating depressant factors, including the cytokines tumor necrosis factor alpha and IL-1beta. At a cellular level, reduced myocardial contractility seems to be induced by both nitric oxide-dependent and nitric oxide-independent mechanisms. The present paper reviews both the clinical manifestations and the molecular/cellular mechanisms of sepsis-induced myocardial depression.

Cardiac Output, Low↗
PubMed2002

Neuropsychological functioning in elderly patients with schizophrenia and Alzheimer's disease.

Cognitive functioning was compared in elderly patients with schizophrenia, elderly patients with probable Alzheimer's disease (AD), and matched healthy controls using a brief neuropsychological battery. Both schizophrenia and AD patients demonstrated marked impairment as compared to controls, with the profile of neuropsychological deficits in both disorders appearing remarkably similar. Only visual confrontation naming, verbal delayed recall, and rate of forgetting (i.e. savings score) significantly differentiated between the two patient groups, with AD patients showing poorer overall recall and more rapid forgetting of verbal information over delay. In addition, schizophrenia subjects showed a significantly greater deficit in visual confrontation naming than the AD group. The relationship of neuropsychological function and clinical symptoms of schizophrenia subjects was also examined. Results showed that word list learning, delayed recall, and rate of forgetting correlated most strongly with positive and negative symptoms. Recent neuropathological studies have indicated abnormalities in specific subfields of the hippocampal formation in schizophrenia that are also severely affected in AD. Though the specific histopathology of the two disorders differs, abnormalities in the common sites may underlie the common neuropsychological profile.

Age Factors↗
PubMed2002

Autonomous neurobiological pathways to late-life major depressive disorder: clinical and pathophysiological implications.

The objective of our study was to elucidate distinct paths to depression in a model that incorporates age, measures of medical comorbidity, neuroanatomical compromise, and cognitive status in a sample of patients with late-life major depressive disorder (MDD) and nondepressed controls. Our study was cross-sectional in nature and utilized magnetic resonance imaging (MRI) estimates of brain and high-intensity lesion volumes together with clinical indices of cerebrovascular and nonvascular medical comorbidity. Neuroanatomic and clinical measures were incorporated into a structural covariance model in order to test pathways to MDD. Our data indicate that there are two paths to MDD; one path is represented by vascular and nonvascular medical comorbidity that contribute to high-intensity lesions that lead to depression. Smaller brain volumes represent a distinct path to the mood disorder. Age influences depression by increasing atrophy and overall medical comorbidity but has no direct impact on MDD. These findings demonstrate that there are distinct biological substrates to the neuroanatomical changes captured on MRI. These observations further suggest that neurobiological mechanisms acting in parallel may compromise brain structure/function, thereby predisposing individuals to clinical brain disorders such as depression.

Affect↗
PubMed2002

Medical burden, cerebrovascular disease, and cognitive impairment in geriatric depression: modeling the relationships with the CART analysis.

Herein, the background information reflecting roles of medical burden, cerebrovascular disease and risk factors, and cognitive impairment in geriatric depression are reviewed. The authors then propose a nonparametric statistical approach to the data analysis of multiple putative causal variables for late-life depression, the Classification and Regression Tree Analysis. This analysis presents a useful approach to modeling nonlinear relationships and interactions among variables measuring physical and mental health, as well as magnetic resonance imaging and cognitive measures in depressed elderly. This method uncovers the existing interactions among multiple predictor variables, and provide thresholds for each variable, at which its predictive power becomes statistically significant. It presents a "hierarchy" of the predictors in a form of a decision tree by finding the best combination of predictors of an outcome. The authors present two models based on demographic variables, measures of vascular and nonvascular medical burden, neuroimaging indices, the Mini-Mental State Examination score, and neuropsychological test scores of 81 elderly depressed subjects. Cognitive tests of verbal fluency and executive function are identified as the best predictors of depression, followed by the frontal lobe volume and Mini-Mental State Examination. The authors observed that an interaction between frontal lobe volume, total lesion volume, and medical burden was predictive of depression.

Journal Article↗