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Biomedical subjects

E Kaplan

Publications and source records attributed to E Kaplan.

At least 37 records · Page 2Linked to original sources
PubMed2000

ATM heterozygosity and breast cancer: screening of 37 breast cancer patients for ATM mutations using a non-isotopic RNase cleavage-based assay.

Based upon the results of several epidemiologic studies, it has been suggested that women who are carriers for a mutation in the ataxia telangiectasia-mutated (ATM) gene are susceptible for the development of breast cancer. Therefore, 37 consecutive breast cancer patients were screened for the presence of a germline ATM mutation using a non-isotopic RNase cleavage-based assay (NIRCA). This paper reports the first use of NIRCA for detection of ATM mutations in breast cancer patients. Using this assay, no ATM mutations were found in our patient population. This result is similar to the findings of other studies that have employed approaches complementary to NIRCA.

Adult↗
PubMed2000

Age effects on executive ability.

Heterogeneity of executive tasks has made it difficult to determine whether there are age-related declines in executive functioning. To address this issue, 112 individuals, 20-79 years old, took the California Trail Making Test (CTMT) and the California Stroop Test (CST), subtests of the Delis-Kaplan Executive Function Scale (D. C. Delis, E. Kaplan, & J. H. Kramer, in press) that include measurement of component skills embedded in the executive function tasks. Multiple regression analyses revealed that after controlling for component skills, age had a significant effect on the executive requirement of the CST, namely speed on the interference condition. Age did not affect switching performance on the letter-number condition of the CTMT. Additional analyses revealed that age was significantly associated with commission of certain types of errors. This study confirms the importance of partialing out components in the assessment of multidimensional cognitive tasks, particularly when making age comparisons. It also emphasizes specificity over generalizability when examining the impact of age on cognition.

Adult↗
PubMed2000

Visuoconstructional problems in dementia: contribution of executive systems functions.

Visuoconstructional ability was assessed by asking patients diagnosed with Alzheimer's disease (AD), ischaemic vascular dementia (IVD), and Parkinson's disease (PD) and a normal control group (NC) to copy a modification of the Rey-Osterrieth Complex Figure (M-ROCF). The drawings of the NC group were superior to all dementia participants. AD patients generally outperformed IVD and PD patients; however, there were few differences between IVD and PD groups. Nonetheless, the drawings of IVD and PD patients were very fragmented and contained numerous perseverations and omissions. Despite these errors, patients with IVD and PD obtained higher delayed recognition memory scores than AD patients. Correlational analyses among dementia patients between neuropsychological tests and the copy of the M-ROCF found that accurate figure copy was most consistently correlated with tests of working memory, that is, tests requiring patients to monitor their behavior and sustain a complex mental set while performing mental manipulations. By contrast, no relationship between executive function tests related to measures of response selection/inhibition or other domains of neuropsychological functioning was found.

Aged↗
PubMed2000

Qualitative block design analysis in posttraumatic stress disorder.

Qualitative and quantitative Block Design performance was examined in Vietnam combat veterans with PTSD diagnoses (n = 23) and Vietnam combat veterans without PTSD or other mental disorders diagnoses (n = 19). Results indicated that PTSD-diagnosed veterans committed more single block rotations than the comparison sample, and that their errors occurred more frequently in right hemispace than errors made by the comparison sample. The two groups did not differ in the number of configural errors made, errors committed in left hemispace, or in quantitative performance measures. Findings are suggestive of relative left hemisphere hypoactivation and are congruent with prior research documenting cerebral asymmetries in emotional disorders.

Affect↗
PubMed2000

Kidney allograft outcome in simultaneous pancreas-kidney transplantation.

BACKGROUND: In simultaneous pancreas-kidney transplantation, with both organs coming from the same donor, the addition of a pancreas to the kidney transplant does not jeopardize the kidney allograft outcome despite higher postoperative SPK morbidity. Pancreas allograft outcome has recently improved due to better organ selection and more accurate surgical techniques. OBJECTIVE: To demonstrate the positive impact of SPK on kidney allograft outcome versus kidney transplantation alone in insulin-dependent diabetes mellitus patients with end-stage renal failure. METHODS: We performed 39 consecutive SPKs in 14 female and 25 male IDDM patients with renal failure after an average waiting time of 9 months. Multi-organ donor age was 30 years (range 12-53). The kidneys were transplanted in the left retroperitoneal iliac fossa following completion of the pancreas transplantation; kidney cold ischemia time was 16 +/- 4 hours. Induction anti-rejection therapy was achieved with polyclonal antithymocytic globulin and methylprednisolone, and maintenance immunosuppression by triple drug therapy (prednisone, cyclosporine or tacrolimus, and azathioprine or mycophenolate mofetil). Infection and rejection were closely monitored. RESULTS: All kidney allografts produced immediate urinary output following SPK. Two renal grafts had mild function impairment due to acute tubular damage but recovered after a short delay. Three patients died from myocardial infarction, cerebrovascular event and abdominal sepsis on days 1, 32 and 45 respectively (1 year patient survival 92%). An additional kidney allograft was lost due to a renal artery pseudo-aneurysm requiring nephrectomy on day 26. Nineteen patients (49%) had an early rejection of the kidney that was resistant to pulse-steroid therapy in 6. No kidney graft was lost due to rejection. Patients with acute kidney-pancreas rejection episodes suffered from severe infection, which was the main cause of morbidity with a 55% re-admission rate. Complications of the pancreas allograft included graft pancreatitis and sepsis, leading to a poor kidney outcome with sub-optimal kidney function at 1 year. Kidney graft survival at one year was 89% or 95% after censoring the data for patients who died with functioning grafts. CONCLUSIONS: Eligible IDDM patients with advanced diabetic nephropathy should choose SPK over kidney transplantation alone from either a cadaver or a living source.

Adolescent↗
PubMed2000

A population approach to cortical dynamics with an application to orientation tuning.

A typical functional region in cortex contains thousands of neurons, therefore direct neuronal simulation of the dynamics of such a region necessarily involves massive computation. A recent efficient alternative formulation is in terms of kinetic equations that describe the collective activity of the whole population of similar neurons. A previous paper has shown that these equations produce results that agree well with detailed direct simulations. Here we illustrate the power of this new technique by applying it to the investigation of the effect of recurrent connections upon the dynamics of orientation tuning in the visual cortex. Our equations express the kinetic counterpart of the hypercolumn model from which Somers et al (Somers D, Nelson S and Sur M 1995 J. Neurosci. 15 5448-65) computed steady-state cortical responses to static stimuli by direct simulation. We confirm their static results. Our method presents the opportunity to simulate the data-intensive dynamical experiments of Ringach et al (Ringach D, Hawken M and Shapley R 1997 Nature 387 281-4), in which 60 randomly oriented stimuli were presented each second for 15 min, to gather adequate statistics of responses to multiple presentations. Without readjustment of the previously defined parameters. our simulations yield substantial agreement with the experimental results. Our calculations suggest that differences in the experimental dynamical responses of cells in different cortical layers originate from differences in their recurrent connections with other cells. Thus our method of efficient simulation furnishes a variety of information that is not available from experiment alone.

Action Potentials↗
PubMed1999

Dynamics of primate P retinal ganglion cells: responses to chromatic and achromatic stimuli.

1. The majority of primate retinal ganglion cells (RGCs) project to the parvocellular layers of the lateral geniculate nucleus (LGN). These P cells play a central role in early visual processing. 2. An improved method of systems analysis has allowed us to explore the dynamics of the colour-opponent subregions of P-cell receptive fields with a single chromatic stimulus. The data show that the centre and surround subregions of the P-cell receptive field have similar temporal responses, but the surround is slightly delayed. The centre and surround demonstrate a large degree of chromatic selectivity. 3. The responses of the centre and surround subregions were fitted with a linear model and the model was used to predict the responses of P cells to new chromatic and achromatic stimuli. Although linear models predict the chromatic responses well, simple linear combinations of centre and surround responses fail to predict P-cell responses to achromatic stimuli. 4. The temporal responses of the different subpopulations of P cells, such as ON/OFF or L-centre/M-centre were not significantly different.

Animals↗
PubMed1999

Internal consistency, temporal stability and neuropsychological correlates of three cognitive components of the Positive and Negative Syndrome Scale (PANSS).

Comprehensive models of schizophrenia have increasingly included symptoms of cognitive dysfunction as an important feature of schizophrenia. Factor analytic studies of the Positive and Negative Syndrome Scale (PANSS) have consistently established cognitively disorganized symptoms as a separate domain from positive and negative symptoms. However, the individual symptom composition of the cognitive domain varies from model to model. The present study explores the temporal stability, internal consistency, concurrent validity, and discriminant validity for three published PANSS factor analytically derived cognitive components (Bell et al., 1994a, Psychiatry Res., 52, 295-303; Dollfus et al., 1991. Eur. Psychiatry, 6, 251-259; Kay and Sevy, 1990. Schizophr. Bull., 16, 537-544). Analyses were conducted using PANSS data from 120 patients with DSM-IV diagnoses of schizophrenia or schizoaffective disorder. Results indicate that the Bell et al. and Kay and Sevy models have similar psychometric properties including adequate temporal stability, internal consistency, and discriminant validity. The Kay model demonstrated somewhat better concurrent validity with cognitive test measures, while the Dollfus model demonstrated relatively poor psychometrics. The symptom composition of a narrowly defined cognitively disorganized subtype and a more broadly defined cognitively impaired subtype are discussed in terms of their value for schizophrenia research.

Adult↗
PubMed1999

Information Multiple Choice among healthy older adults: characteristics, correlates, and clinical implications.

Information Multiple Choice (WAIS-R-NI, Kaplan et al., 1991), may be valuable when used in conjunction with the standard Information subtest. Due to the reduced retrieval demands posed by its recognition format, scores should be even less susceptible to neuropathology or normal aging than are those on the standard (recall) test, facilitating assessment of premorbid attainment in individuals suffering from retrieval-related memory deficits. We provide reliability, validity, and normative data on Information Multiple Choice from a sample (N = 177) of healthy adults aged 50 - 90 years. Information Multiple Choice correlates strongly with the standard Information subtest (r = .81) and, as predicted and unlike the standard test, does not decline even in very old age. The construct validity of Information Multiple Choice is supported, and its clinical utility will be enhanced by these normative data.

Adult↗
PubMed1999

Personality and psychopathology in schizophrenia: the association between personality traits and symptoms.

Research has indicated that stable individual differences in personality exist among persons with schizophrenia, and that they likely predate the onset of illness. Little is known, however, about whether individual differences in personality are related to levels of psychopathology. This study tested the hypotheses that levels of Extroversion, Neuroticism, and Psychoticism are associated with symptomatology. Accordingly, measures of these dimensions of personality and of symptomatology were obtained simultaneously for 113 male subjects with schizophrenia or schizoaffective disorder. Next, subjects were characterized as having high or low levels on each personality dimension and their scores on the five components of the Positive Negative Syndrome Scale were compared using multivariate and univariate procedures. Results indicate that extroverted subjects had lower levels of Positive, Negative, and Emotional Discomfort symptoms, and higher levels of Excitement symptoms than introverted subjects. Subjects with higher levels of Neuroticism had higher levels of Positive and Emotional Discomfort symptoms than subjects with lower levels of Neuroticism. No differences in symptoms were found among subjects with higher versus lower levels of Psychoticism. Results suggest individual differences in personality are associated with psychopathology in schizophrenia and may help further explain the heterogeneity widely observed in this disorder.

Adaptation, Psychological↗
PubMed1999

Configural errors on WISC-III block design.

This study describes two experiments undertaken to explore the clinical significance and cognitive substrates of Block Design broken configurations in children. Broken configurations were defined as instances in which the child placed a block outside the 2 x 2 or 3 x 3 square matrix. In Experiment 1, 336 normal children between the ages of 6 and 14 were administered WISC-III Block Design. Broken configurations were fairly common, but almost always self-corrected. The tendency to break configurations was inversely related to overall Block Design performance and mother's level of education, and directly related to the perceptual cohesiveness of the design. In Experiment 2, children were administered WISC-III Block Design and a global-local similarity judgment task. The frequency of broken configurations was inversely related to global perceptual bias. Taken together, the results of these experiments indicate that while broken configurations are common, particularly on designs with high perceptual cohesiveness, a high number of broken configurations or final answers containing broken configuration are associated with weaker visuospatial skills. Broken configurations are also made more frequently by children whose perception is less influenced by the global properties of spatial stimuli.

Adolescent↗
PubMed1998

Personality and psychosocial dysfunction in schizophrenia: the association of extraversion and neuroticism to deficits in work performance.

Research on vocational dysfunction in schizophrenia has as yet only examined associated features of illness. We hypothesized that personality variables may be also associated with work function. We reasoned that higher levels of extraversion and neuroticism would predict poor function by virtue of the social support seeking and passive/avoidant coping styles associated with each. To test this, multiple regressions were conducted in which measures of extraversion and neuroticism predicted work performance among 43 subjects with schizophrenia or schizoaffective disorder. Higher levels of extraversion and neuroticism significantly predicted poorer function, accounting for between 7% and 27% of the variance in global cooperativeness, work quality, work habits and personal presentation measures of work behavior. The potential importance of assessing personality in rehabilitation is discussed.

Adult↗
PubMed1998

Representation of spatial frequency and orientation in the visual cortex.

Knowledge of the response of the primary visual cortex to the various spatial frequencies and orientations in the visual scene should help us understand the principles by which the brain recognizes patterns. Current information about the cortical layout of spatial frequency response is still incomplete because of difficulties in recording and interpreting adequate data. Here, we report results from a study of the cat primary visual cortex in which we employed a new image-analysis method that allows improved separation of signal from noise and that we used to examine the neurooptical response of the primary visual cortex to drifting sine gratings over a range of orientations and spatial frequencies. We found that (i) the optical responses to all orientations and spatial frequencies were well approximated by weighted sums of only two pairs of basis pictures, one pair for orientation and a different pair for spatial frequency; (ii) the weightings of the two pictures in each pair were approximately in quadrature (1/4 cycle apart); and (iii) our spatial frequency data revealed a cortical map that continuously assigns different optimal spatial frequency responses to different cortical locations over the entire spatial frequency range.

Animals↗
PubMed1998

A mathematical model of HIV transmission in NSW prisons.

A mathematical model was developed to estimate HIV incidence in NSW prisons. Data included: duration of imprisonment; number of inmates using each needle; lower and higher number of shared injections per IDU per week; proportion of IDUs using bleach; efficacy of bleach; HIV prevalence and probability of infection. HIV prevalence in IDUs in prison was estimated to have risen from 0.8 to 6.7% (12.2%) over 180 weeks when using lower (and higher) values for frequency of shared injections. The estimated minimum (and maximum) number of IDU inmates, infected with HIV in NSW prisons was 38 (and 152) in 1993 according to the model. These figures require confirmation by seroincidence studies.

Databases, Factual↗
PubMed1998

Affect recognition in deficit syndrome schizophrenia.

This study has three aims: (1) to compare a deficit syndrome schizophrenia sample (n=19) with a non-deficit sample (n=50) on affect recognition; (2) to determine the association between individual deficit criteria and affect recognition performance in the deficit sample; and (3) to compare the deficit syndrome and negative syndrome samples with respect to affect recognition test performance. Results revealed that the deficit sample had significantly lower adjusted mean affect recognition scores than the non-deficit sample. In addition, 17 of the 19 subjects with deficit syndrome had impairments in affect recognition, whereas, non-deficit subjects were only slightly more likely to score in the impaired range than the unimpaired range. Within the deficit sample Diminished Sense of Purpose was the criterion most strongly associated with affect recognition impairment. Finally, a group of subjects classified as having prominent negative symptoms did not demonstrate the same pattern of impairment as shown by the deficit syndrome sample. The relationship between affect recognition, information processing and the deficit syndrome is discussed along with implications for classification in schizophrenia.

Adult↗