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Biomedical subjects

S Halperin

Publications and source records attributed to S Halperin.

33 records · Page 2Linked to original sources
PubMed1993

Stress and unaided smoking cessation: a prospective investigation.

A prospective design was used to determine the outcomes associated with unaided smoking cessation and the influence of stress on cessation. Heavy smokers (N = 308) completed stress-related measures and were then recontacted at 1, 6, and 12 months. At each follow-up, they indicated their smoking status (which was confirmed by collateral report and biochemical tests) and completed several stress-related questionnaires. Results indicated that 33% of subjects smoked continuously throughout the year, 39% quit briefly but subsequently relapsed, and 15% quit (confirmed biochemically). An additional 7% reported that they had quit, but this could not be confirmed, and 6% were lost to follow-up. Compared with nonquiters, quitters reported less perceived stress, greater self-efficacy, greater use of problem solving and cognitive restructuring, and less reliance on wishful thinking, self-criticism, and social withdrawal. A model to forecast quitting was built and cross-validated.

Adult↗
PubMed1993

Deficient priming activity of newborn cord blood-derived polymorphonuclear neutrophilic granulocytes with lipopolysaccharide and tumor necrosis factor-alpha triggered with formyl-methionyl-leucyl-phenylalanine.

Newborn infants are more susceptible to bacterial infections than adults. This susceptibility has been attributed to defects in humoral and cellular activity. Host cellular activity can be modified by factors produced by bacteria or the host in response to infection. We assessed the effect of two factors associated with gram-negative bacterial infection, lipopolysaccharide (LPS) and TNF-alpha, on polymorphonuclear neutrophilic granulocytes (PMN) obtained from adult or newborns (umbilical cord blood). PMN were primed in vitro with LPS (10 micrograms/L) or TNF-alpha (10(-9) M) for 45 min and then assessed, using a chemiluminescence (CL) assay as an indicator of oxidative radical production with formyl-methionyl-leucyl-phenylalanine as the trigger for CL initiation. CL activity of unprimed PMN was similar for adults and newborns (13.3 and 13.7 CL units, respectively). After priming with LPS, CL activity was increased to 43.4 CL units for PMN from adults but to only 17.6 CL units for PMN from newborns (p < 0.001, adults versus newborn increment). Priming of PMN with LPS was most effective when autologous plasma was present. Using FITC-conjugated LPS and a flow cytometry assay, we could demonstrate no difference between the binding affinity of LPS for adult and newborn PMN. However, formyl-methionyl-leucyl-phenylalanine binding studies indicated that adult PMN had a higher number of binding sites. TNF-alpha priming of newborn PMN was also ineffective. Adult PMN increased CL activity by 3.9-fold when primed with TNF-alpha, whereas newborn PMN increased by only 1.75-fold (p < 0.005). This priming deficiency was not attributable to TNF-alpha receptors because phycoerythrin-conjugated TNF-alpha was associated with PMN from adults and newborns equally. Thus, PMN from newborns are not primed effectively in vitro with LPS or TNF-alpha. This defect may contribute to neonatal susceptibility to bacterial infection.

Adult↗
PubMed1992

Prolonged survival of Bordetella pertussis in a simple buffer after nasopharyngeal secretion aspiration.

A simple method for recovery of Bordetella pertussis is described using phosphate-buffered saline containing a casein hydrolysate for transporting secretions collected by nasopharyngeal aspirate. Bordetella pertussis was reisolated from 92% of clinical specimens held at 4 degrees C for 1 week and from all specimens held at -20 degrees C. This method will facilitate the centralization of laboratory facilities for the diagnosis of pertussis.

Bacteriological Techniques↗
PubMed1989

The development of identification in Freudian theory.

Once identification achieved its status as a specific psychoanalytic concept it followed a process of reconceptualization that emerged from the different clinical and theoretical contexts in which Freud approached and explained the phenomenon. In tracing the unfolding of the theory of identification throughout Freud's works, we have accounted for the following steps: First, in his correspondence with Fliess, Freud announced topics that would subsequently be theoretically processed. Second, in the first topography, identification was explored in the contexts of hysteria and dreams, and elaborated through reference to two psychic scenes with their respective modes of psychic functioning. Third, in the period of transition to the second topography identification was defined as a substitute for an object relationship and as a preliminary stage of object choice. Interlocked with the concept of narcissism, it produced a reconceptualization of the ego that led to the second topography. Finally, the tripartite model proposed in the second topography manifests the consolidation of the structuring function of identification, since the psychic structure is therein conceived of as resulting from the vicissitudes of object relationships.

Ego↗
PubMed1986

Spurious correlations--causes and cures.

Although the Pearson Product--Moment Correlation Coefficient is one of the most widely used statistics in the health and behavioral sciences, it is not always appreciated that the critical assumption of bivariate normality underlies its interpretation. When variables have marginal distributions which are skewed or have heavy tails which produce outliers, correlations may be either spuriously large or small. Having diagnosed problems through exploratory data analysis, one must take the appropriate corrective action, such as re-expressing (transforming) variables or selectively discarding discordant observations.

Research Design↗
PubMed1976

Partitioning chi-square the analysis of contingency tables with repeated measurements.

Categorical variables are commonly used in gerontological research. Although analysis of such variables presents no problem as long as the observations are independent, problems do arise when they are found in a design with repeated measurements. In this paper, two procedures from the statistics literature are combined to provide an analysis for data from a mixture of between and within categorical variables. First, a response pattern is used to form a contingency table with observations which are completely independent. Next, the Pearson chi-square statistic from the table is partitioned to provide tests analogous to simple effects in analysis of variance.

Aged↗
PubMed1976

Species and hybrid differences in frequencies of play and agonistic actions in canids.

Developmental changes in the frequency of occurrence of some 23 action patterns were studied in pairs of coyotes, wolves, dogs and their hybrids. Over 4,300 entries were recorded from days 24--42 (85.5 h observations in toto). All subjects showed a decrease in contactual behaviors from 24--30 days, and a subsequent increase in play fighting and chasing. In all species, with the exception of the coyotes, the bite was inhibited and play behavior was recorded from 24 days onwards, but only after the 30th day in the coyotes. Species differences in occurrence and frequency of certain action patterns were evident in the wolves, coyotes and dogs, and these differences were also reflected in their hybrids.

Age Factors↗