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Biomedical subjects

T Sherman

Publications and source records attributed to T Sherman.

25 records · Page 2Linked to original sources
PubMed1985

Categorization skills in infants.

The prototypical category-learning experiences with which infants are confronted are ones in which they have had prior experience with and have clearly noted the differences among a set of objects. Their task, then, is to notice also the similarities among the objects and to form a category based on these similarities. The goals of the current experiments were to create a laboratory situation in which it was clear that 10-month-old infants were distinguishing one category exemplar from another, and then to determine the structure of the category representation the infants developed under these learning conditions. A set of artificially created face stimuli was used in which the mean and modal prototypes were distinct. The infants' performance could not be explained by the context theory; they appear to have retained a count of the feature values observed during study. These data give support to the claim that prior to language, infants have available strategies for abstracting category-level information from their perceptual experiences with discriminable objects and events.

Attention↗
PubMed1984

Studies of visual information processing in schizophrenic children.

11 children meeting DSM III criteria for schizophrenia (mean age approximately 12 years), a group of normal children matched in mean mental age to the schizophrenic children, and a group of younger normal children (mean age 6.6 years) were administered a series of visual information-processing tasks in order to isolate core information-processing impairments in childhood onset schizophrenia. In Experiment 1, the schizophrenic children showed impairment relative to the MA-matched normals and performed at the level of the younger normal children on a forced-choice partial-report version of the span-of-apprehension task. Previous research has shown that this task is sensitive to dysfunction in both actively and partially recovered schizophrenic adults as well as a subset of foster children at risk for schizophrenia. Experiment 2 delimited the source of the information-processing impairment in schizophrenic children by ruling out a number of possible causes of impairment and suggesting that schizophrenic children use the same information-acquisition strategies as MA-matched children but less efficiently. Experiment 3 revealed that, consistent with the previous research, the schizophrenic children were comparable with the MA-matched controls on a full-report span-of-apprehension task that placed heavy demands on iconic and short-term memory. Both the schizophrenic and MA-matched normals performed significantly better than the younger normal children. Taken collectively, the results of the three experiments suggest that all groups of children engaged in a serial information-processing strategy while performing on the partial-report version of the span-of-apprehension task. The differential impairment of the schizophrenic children on the partial-report versions but not the full-report version of the span-of-apprehension task seems to reflect inefficiencies in controlled attentional processes that normally develop during middle childhood.

Attention↗
PubMed1975

Picture memory improves with longer on time and off time.

Both recognition and recall of pictures improve as picture presentation time increases and as time between pictures increases. Processing of the pictures, rehearsal and/or encoding, continues after the picture has disappeared, just as for verbal material. Both the results and conclusions stand in contrast to those of Shaffer and Shiffrin.

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PubMedDate not supplied

Bcl-2 expression in Langerhans' cell histiocytosis.

Langerhans' cell histiocytosis (LCH) is an abnormal accumulation of dendritic histiocytes of unknown pathogenesis. It has recently been shown to be a clonal process. Bcl-2 is a proto-oncogene whose protein product is known to inhibit apoptosis. The overexpression of bcl-2 has been demonstrated in a number of neoplasms, presumably prolonging the survival of the neoplastic cells. We examined the expression of bcl-2 in normal Langerhans' cells in the skin and in LCH by immunohistochemistry for protein and in situ hybridization for mRNA to see if it could be implicated in the pathogenesis of this disorder. Additionally, we performed Southern analysis to determine if genomic rearrangement of the bcl-2 gene occurs in cases of LCH. Bcl-2 was not detected in normal skin Langerhans' cells. Eleven of thirteen cases of LCH demonstrated bcl-2 protein expression in the cytoplasm of the Langerhans' cells by immunohistochemistry, while 12 of 13 cases had evidence of bcl-2 mRNA by in situ hybridization. Southern analysis revealed a germline configuration of the bcl-2 gene in the five cases studied. These findings suggest that bcl-2 expression is present and up-regulated in pathologic Langerhans' cells, however, this overexpression does not appear to be due to genomic rearrangement.

Biomarkers↗
PubMedDate not supplied

Validity of criteria used for detecting underuse of coronary revascularization.

OBJECTIVE: To assess criteria used for detecting underuse of coronary artery revascularization procedures in terms of patient outcomes. DESIGN: Retrospective cohort study using medical records supplemented by a telephone survey and review of county death records. SETTING: Four public hospitals and two academically affiliated private hospitals in Los Angeles County, California. PARTICIPANTS: A total of 671 patients who had coronary angiography between June 1, 1990 and September 30, 1991, and who met explicit clinical criteria for the necessity of coronary artery bypass graft (CABG) surgery or percutaneous transluminal coronary angioplasty (PTCA). MAIN OUTCOME MEASURES: For all patients (n = 671), we estimated the association between receipt of necessary revascularization and mortality (median follow-up after angiography, 797 days) after adjusting for potential confounders. For the patients completing the telephone interview (n = 374), we examined the relationship between receipt of necessary revascularization and frequency of chest pain. RESULTS: Patients who received necessary revascularization within 1 year of angiography had lower mortality than those who did not (8.7% vs 15.8%, P = .01), and this association persisted after adjustment for extent of coronary artery disease, clinical symptom complex, ejection fraction, and cardiac surgical risk index (adjusted odds ratio = 0.49; 95% confidence interval, 0.28 to 0.86). The same general results were obtained whether revascularization was received within 1 year or within 30 days of the catheterization, whether panelists' ratings or individual clinical variables were entered as covariates, and whether the statistical procedure used was logistic regression or Cox proportional hazards analysis. In addition, among patients responding to the telephone survey, those receiving necessary revascularization had less chest pain at follow-up (P = .03). CONCLUSIONS: Among patients meeting criteria for the necessity of revascularization, those receiving a revascularization procedure within 1 year had lower mortality than those treated medically. These results support the validity of the RAND/UCLA criteria for detecting underuse of these procedures, but more research is needed to confirm the findings and to determine the validity of guidelines for other procedures.

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