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Biomedical subjects

D Friedman

Publications and source records attributed to D Friedman.

At least 73 records · Page 4Linked to original sources
PubMed1998

Interleukin-15 augments superoxide production and microbicidal activity of human monocytes against Candida albicans.

Interleukin-15 (IL-15) is a newly described cytokine that shares biological activities with IL-2. We report here results demonstrating the ability of IL-15 to enhance superoxide production and antifungal activity of human monocytes. After 18 and 48 h of treatment with IL-15, human elutriated monocytes manifested enhanced superoxide production in response to either phorbol myristate acetate or opsonized Candida albicans blastoconidia. Similar results were obtained when monocytes were treated with IL-2, but to a lesser extent. Combination studies with IL-15 and IL-2 showed no additive or synergistic effects. Following incubation of monocytes with IL-15 for 18 h, there was no significant increase in mRNA transcripts for components of the NADPH oxidase complex, p40-phox, p47-phox, and gp91-phox, suggesting a posttranscriptional modulation of enhanced superoxide production. Antibodies against the gamma chain of the IL-2 receptor and, to a lesser extent, against the beta chain partially abrogated the IL-15-mediated enhanced superoxide production. Additionally, human monocytes showed enhanced killing activity against C. albicans after 18 h of incubation with IL-15 or IL-2, but this treatment did not enhance the ability of these cells to phagocytose the organism. In addition, the enhanced fungicidal activity seen after 18 h of treatment was no longer detectable after 48 h of cytokine treatment. Culture supernatants from the IL-15-treated monocytes were assayed for the presence of other proinflammatory cytokines. IL-15 treatment did not induce the release of detectable levels of tumor necrosis factor alpha, IL-1beta, or IL-12. Our results indicate that IL-15 upregulates the microbicidal activity of human monocytes against C. albicans.

Candida albicans↗
PubMed1998

Nipplephobic?

Explore the source record for details and available documents.

Breast Feeding↗
PubMed1998

Association between childhood acute lymphoblastic leukemia and use of electrical appliances during pregnancy and childhood.

As part of a comprehensive study of residential magnetic field exposure in nine midwestern and mid-Atlantic states, we evaluated the use of appliances by 640 patients with acute lymphoblastic leukemia, 0-14 years of age, diagnosed between 1989 and 1993, and 640 matched control children. Mothers were interviewed regarding use of electrical appliances during their pregnancy with the subject and the child's postnatal use. The risk of acute lymphoblastic leukemia was elevated in children whose mothers reported use of an electric blanket or mattress pad during pregnancy [odds ratio (OR) = 1.59; 95% confidence interval (CI) = 1.11-2.29] but was reduced for use of sewing machines during pregnancy (OR = 0.76; 95% CI = 0.59-0.98). The risk of acute lymphoblastic leukemia was increased with children's use of electric blankets or mattress pads (OR = 2.75; 95% CI = 1.52-4.98) and three other electrical appliances (hair dryers, video machines in arcades, and video games connected to a television), but the patterns of risk for duration in years of use and frequency of use were inconsistent for most appliances used by children. Risks rose with increasing number of hours per day children spent watching television, but risks were similar regardless of the usual distance from the television. The inconsistency in the dose-response patterns for many appliances, reporting and selection bias, and the lack of an effect for measured 60 Hertz magnetic fields or wire codes in our companion study must be considered before ascribing these associations to exposures from magnetic fields.

Case-Control Studies↗
PubMed1998

Individual differences in P3 scalp distribution in older adults, and their relationship to frontal lobe function.

There is evidence that frontal lobe function may diminish in normal aging. The P3 component of the event-related brain potential (ERP) elicited by target events in an oddball paradigm becomes more frontally oriented in elderly subjects. It was hypothesized that the extent to which the P3 distribution is frontally oriented in old subjects may index less efficient frontal lobe function. In this study, bootstrapping methods were used to establish the reliability of the locations of maxima of surface brain activity obtained with ERP recordings from young and old subjects. The results indicated that brain activity maxima are reliable for a given individual. However, among the elderly only, there were also clear individual differences in the distribution of the P3 component elicited by target stimuli in an oddball paradigm. On the basis of these differences, the old subjects were divided into two groups. In line with predictions, those elderly subjects who showed frontal-maximal P3 scalp distributions had lower performance on standardized neuropsychological tests of frontal lobe function than those elderly subjects who showed posterior-maximal scalp topographies.

Adult↗
PubMed1997

Aortic stenosis in hypoplastic right heart syndrome, associated with interstitial deletion of chromosome 2.

This report describes a rare case of moderate to severe valvular aortic stenosis in the setting of severe tricuspid stenosis, pulmonary atresia with intact interventricular septum and right ventricular dependent coronary circulation. We discuss the clinical, hemodynamic, echocardiographic and angiocardiographic findings on this rare case and comment on accompanied malformations, with its possible association observed to the interstitial deletion of band q22 or q24 of the long arm of chromosome 2.

Abnormalities, Multiple↗
PubMed1997

Item and source memory: differential age effects revealed by event-related potentials.

The neural substrates of age-related memory differences were evaluated by recording event-related potentials (ERPs) from young and older adults during a recognition memory paradigm. Subjects studied two temporally distinct lists of sentences (each with two nouns) and were tested for their memory of the nouns and of the list (i.e. temporal source) in which they had occurred. Compared with the young, the old showed a greater source than item memory performance decrement. Both age groups showed equivalent posterior-maximal old/new ERP effects. However, only the young produced a frontal-maximal, late onset old/new effect that differed as a function of subsequent source attribution. Age-related explicit memory differences may be due to a deficit in a prefrontal cortical system that underlies source memory.

Adult↗
PubMed1997

Mismatch negativity during attend and ignore conditions in Alzheimer's disease.

Mismatch negativities (MMNs) of the event-related potential to deviant tones and environmental sounds were recorded during active and ignore oddball sequences in young and elderly controls and patients with probable Alzheimer's disease (PAD). MMNs were smaller in the PAD waveforms compared to those of the controls, suggesting a degraded sensory memory trace in these subjects; however, under ignore conditions, environmental sounds elicited robust MMNs in the PAD group along with N2b and novelty P3 components in similar fashion to controls. As N2b and P3 are usually elicited by attended stimuli, these data suggest that in the PAD subjects, the highly deviant events involuntarily captured attention, perhaps reflecting the activation of an attentional switching mechanism. Because this passive switching is thought to reflect activation of a mechanism located in the frontal lobes, the data suggest that this putative frontal lobe mechanism is relatively intact in the early stages of the disease.

Acoustic Stimulation↗
PubMed1997

Hernia repair in elderly patients.

BACKGROUND: This study evaluates a 5-year experience of the management of the most frequent abdominal wall hernias in an elderly population. METHODS: From April 1990 to December 1995, 231 inguinal, 12 femoral and seven umbilical hernias were repaired in 221 patients (mean age 74 (range 66-93) years). Concomitant diseases were present in 157 patients. A mesh repair was performed with 'tension-free' or 'plug' techniques in all but 23 inguinal and two femoral hernia repairs, in which the Bassini or Shouldice procedures were adopted. Ten emergency hernia repairs were performed for strangulation. A total of 232 operations, including four emergency hernia repairs, were carried out under local anaesthesia. RESULTS: There was no perioperative mortality. Acute intestinal bleeding occurred 2 days after surgery in a patient with colonic diverticular disease. Urinary retention occurred once following emergency hernia repair under general anaesthesia and twice after elective hernia repair under local anaesthesia. Local complications included four scrotal haematomas (2 per cent), three wound infections (1 per cent) and one case of orchitis with atrophy after repair of a recurrent hernia. There was one recurrence after a Bassini repair and one after Shouldice inguinal herniorrhaphy. No recurrence was observed after mesh repair. CONCLUSION: Local anaesthetic mesh hernia repair is safe and effective in elderly patients. Age should be no bar to elective hernia repair. This policy should avoid the complications of emergency operation.

Aged↗
PubMed1997

Picture naming by young children: norms for name agreement, familiarity, and visual complexity.

Researchers concerned with the development of cognitive functions are in need of standardized material that can be used with both adults and children. The present article provides normative measures for 400 line drawings viewed by 5- and 6-year-old children. The three variables obtained-name agreement, familiarity, and visual complexity-are important because of their potential effect on memory and other cognitive processes. The normative data collected in the present study indicate that young children are different from adults in both the name most frequently assigned and the number of alternative names provided. The alternative names given by the children are either coordinate names or names of objects that are visually similar to the pictured object. In addition, the failure (to name) rate is higher among young children compared to adults. Thus, we conclude that unequivocal interpretation of age-related differences in cognitive functions can be made only when age-appropriate pictorial stimuli are chosen.

Adult↗
PubMed1997

Fast and localized event-related optical signals (EROS) in the human occipital cortex: comparisons with the visual evoked potential and fMRI.

Localized evoked activity of the human cortex produces fast changes in optical properties that can be detected noninvasively (event-related optical signal, or EROS). In the present study a fast EROS response (latency approximately 100 ms) elicited in the occipital cortex by visual stimuli showed spatial congruence with fMRI signals and temporal correspondence with VEPs, thus combining subcentimeter spatial localization with subsecond temporal resolution. fMRI signals were recorded from striate and extrastriate cortex. Both areas showed EROS peaks, but at different latencies after stimulation (100 and 200-300 ms, respectively). These results suggest that EROS manifests localized neuronal activity associated with information processing. The temporal resolution and spatial localization of this signal make it a promising tool for studying the time course of activity in localized brain areas and for bridging the gap between electrical and hemodynamic imaging methods.

Adult↗
PubMed1997

A developmental study of the effect of temporal order on the ERPs elicited by novel environmental sounds.

Event-related brain potentials (ERPs) were recorded from 16 subjects in each of the following age groups, 5-7, 9-11, 14-16, and 20-28 years of age. Subjects performed a novelty oddball task, in which frequent, standard tones (80% probability) were intermixed with infrequent tones to which the subject responded (10%), along with 48 unique novel, environmental sounds (10%). Analyses focused on the effects of temporal order (either serial order within the block or block number) in interaction with age group on the ERPs to the novel sounds. The amplitude and scalp distribution of two ERP components were analyzed, the 'novelty P3,' assumed to reflect aspects of the orienting response, and the P32, a component that may be synonymous with the P3b. Evidence suggests that the frontal aspect of the scalp distribution of the novelty P3 depends upon the integrity of the prefrontal cortex. Temporal order produced systematic (primarily linear) reductions in novelty P3 amplitude that were greater at frontal than posterior electrode sites. The P3(2) did not show consistent effects of temporal order. Both of these phenomena were highly similar for all four age groups. It is concluded that the brain's response to novelty is similar across a wide age range, involving a neural circuit with both frontal and posterior elements.

Acoustic Stimulation↗
PubMed1997

Dissociations between memory for temporal order and recognition memory in aging.

Young and old subjects participated in an experiment in which trials testing memory for temporal order (recency memory) and recognition memory were randomly intermixed with study trials in a continuous sequence. A dissociation was found between recency and recognition memory performance for pictorial stimuli. Relative to young adults, older adults performed at chance on recency memory trials whereas they were not impaired on recognition memory. Recency performance was correlated with measures derived from the Wisconsin Card Sorting test, whereas recognition performance was not. The results are discussed in terms of the role of the frontal lobes in temporal-order memory and of possible frontal lobe deterioration in normal aging.

Adult↗
PubMed1997

Temporal segregation in coexisting spiny mice (genus Acomys): role of photoperiod and heterospecific odor.

Daily rhythms of activity and body temperature were measured in golden spiny mice Acomys russatus, acclimated for 2 weeks, at least, to 2 different photoperiod regimes (16L:8D; 8L:16D) at a constant ambient temperature of 28 degrees C. For recording body temperature, VM-FM (Mini-Mitter Co. Inc., Sunriver, OR) transmitters were implanted. For activity measurements, an infrared sensor (Hengstar BL 68 907F, Japan, using a Lodestar PS-303 power supply, Taiwan) mounted on each cage. Both rhythms were also measured in the same individuals exposed to chemical signals released in the urine of A. cahirinus. The results of this study show that both rhythms of A. russatus correlate and respond to changes in photoperiod regimens, as well as to the chemical signals. However, the correlation changes under the 2 photoperiod regimens. Under LD acclimation, a decrease in the correlation is noted, as a response to the addition of chemical signals. Our results suggest that the different responses due to the different light regimens represent 2 seasons in nature, where presumably each season demands a different physiological response.

Animals↗
PubMed1997

An overview of age-related changes in the scalp distribution of P3b.

In this overview of 7 studies, the scalp distribution of the P3b component (i.e. the P3 or P300) of the event-related potential elicited by target events in young and older adults was assessed. The target P3b data were recorded in either auditory oddball paradigms or in visual study tasks in which orienting activity was manipulated (as a within-subjects variable) in investigations of indirect memory. Some of the studies required choice reaction time responses, whereas others required responses only to the target stimuli. Motor response requirements had a profound effect on the P3b scalp distribution of older but not of younger subjects. The presence of a frontally oriented scalp focus in the topographies of the older adults in most of the tasks described here is consistent with older adults continuing to use prefrontal processes for stimuli that should have already been well encoded and/or categorized. However, although older subjects generally had different P3b scalp distributions than younger subjects, their scalp distributions were modulated similarly by task requirements. These data suggest that similar mechanisms modulate the scalp distribution of P3b in older compared to younger adults. However, in the older adult, these scalp distribution changes in response to task demands are superimposed on a frontally oriented scalp focus due to a putative frontal lobe contribution to target P3b topography.

Adult↗
PubMed1997

Old/new differences in direct and indirect memory tests using pictures and words in within- and cross-form conditions: event-related potential and behavioral measures.

Indirect measures of repetition priming are more sensitive to changes in surface features than are direct measures of memory. This dissociation may reflect differences in the extent to which the two tasks rely on form-specific processes, or on the activation of different memory systems. To assess this, subjects at study made semantic discriminations to a mixed list of pictures and words. At test, half the concepts were repeated in the surface form presented at study while half were repeated in the other surface form. Subjects in the indirect test continued making the same discrimination, whereas those in the direct test performed a yes/no recognition task. For both tasks, significant old/new within-form differences were found for event-related potential (ERP) and reaction time (RT) measures. Cross-form old/new differences were reliable only for the word-picture condition in the direct task and only for the ERP indices. These data suggest that both direct and indirect memory tasks are influenced by form-specific as well as form-non-specific processing, and that neither the transfer-appropriate processing nor memory systems approaches can completely account for this pattern of results.

Adult↗
PubMed1997

High-dose mitoxantrone with peripheral blood progenitor cell rescue: toxicity, pharmacokinetics and implications for dosage and schedule.

The optimal use of mitoxantrone (NOV) in the high-dose range requires elucidation of its maximum tolerated dose with peripheral blood progenitor cell (PBPC) support and the time interval needed between drug administration and PBPC reinfusion in order to avoid graft toxicity. The aims of this study were: (1) to verify the feasibility and haematological toxicity of escalating NOV up to 90 mg m(-2) with PBPC support; and (2) to verify the safeness of a short (96 h) interval between NOV administration and PBPC reinfusion. Three cohorts of ten patients with breast cancer (BC) or non-Hodgkin's lymphoma (NHL) received escalating doses of NOV, 60, 75 and 90 mg m(-2) plus melphalan (L-PAM), 140-180 mg m(-2), with PBPC rescue 96 h after NOV. Haematological toxicity was evaluated daily (WHO criteria). NOV plasma pharmacokinetics was also evaluated, as well as NOV cytotoxicity against PBPCs. Haematological recovery was rapid and complete at each NOV dose level without statistically significant differences, and there were no major toxicities. NOV plasma concentrations at the time of PBPC reinfusion were below the toxicity threshold against haemopoietic progenitors. It is concluded that, when adequately supported with PBPCs, NOV can be escalated up to 90 mg m(-2) with acceptable haematological toxicity. PBPCs can be safely reinfused as early as 96 h after NOV administration.

Antineoplastic Agents↗
PubMed1997

An in vitro method for detecting infectious Cryptosporidium oocysts with cell culture.

Current assay methods to detect Cryptosporidium oocysts in water are generally not able to evaluate viability or infectivity. A method was developed for low-level detection of infective oocysts by using HCT-8 cells in culture as hosts to C. parvum reproductive stages. The infective foci were detected by labeling intracellular developmental stages of the parasite in an indirect-antibody assay with a primary antibody specific for reproductive stages and a secondary fluorescein isothiocyanate-conjugated antibody. The complete assay was named the focus detection method (FDM). The infectious foci (indicating that at least one of the four sporozoites released from a viable oocyst had infected a cell) were enumerated by epifluorescence microscopy and confirmed under Nomarski differential interference contrast microscopy. Time series experiments demonstrated that the autoreinfective life cycle in host HCT-8 cells began after 12 h of incubation. Through dilution studies, levels as low as one infectious oocyst were detected. The cell culture FDM compared well to other viability assays. Vital stains and excystation demonstrated that oocyst populations less than 1% viable (by vital dyes) and having a low sporozoite yield following excystation could not infect host cells. Until now, the water industry has relied on an oocyst detection method (under an information collection regulation) that is unable to determine viability. The quantifiable results of the cell culture method described demonstrate two important applications: (i) an infectivity assay that may be used in conjunction with current U.S. Environmental Protection Agency-mandated detection methodologies, and (ii) a method to evaluate oocyst infectivity in survival and disinfection studies.

Animals↗