Search PubMed⌕ Search

Biomedical subjects

C Pearson

Publications and source records attributed to C Pearson.

At least 19 recordsLinked to original sources
PubMed2002

CML leukapheresis products can be enriched for CD34+ cells and simultaneously depleted of CD15+ cells using a simple Ab cocktail.

BACKGROUND: CML progenitor-cell studies would be greatly facilitated if samples could be repeatedly accessed from a source of well-characterized cells. The present study was designed to develop a simple, inexpensive Ab cocktail that would provide subpopulations of cells enriched for CD34+ cells and simultaneously depleted of CD15+ mature myeloid cells. METHODS: Cells from leukapheresis products from CML patients at diagnosis were incubated with each of two Ab cocktails. The standard cocktail (debulking, DB), containing 11 Abs, is recommended for obtaining a highly enriched population of CD34+ cells. The efficacy of an alternative, simpler cocktail (CML custom, CC), containing only four Abs was tested. The recoveries of CD34+ cells, CD15+ cells, colony-forming unit granulocyte-macrophage, and LTCIC were monitored. The samples were then cryopreserved, thawed, and the recoveries remeasured. RESULTS: The purity of CD34+ cells was significantly superior using the DB cocktail than with the CC cocktail. Conversely, using the CC cocktail, the yield of CD34+ cells was significantly higher compared to the DB cocktail. These results were maintained even when the amount of Ab was reduced 10-fold. Both Ab cocktails consistently removed > 99% of the CD15+ cells. Consistent with the CD34+ cell-enrichment data, higher colony-forming cell (CFC) frequencies were obtained with the DB cocktail, although superior yields of CFC were obtained with the CC cocktail. After cryopreservation and thawing the yield of CD34+ cells remained high, and a further reduction in the number of CD15+ cells was obtained. DISCUSSION: A method is described that allows the rapid and efficient debulking of large CML samples. This strategy will provide a source of well-characterized CML stem/progenitor cells that can be repeatedly accessed.

Antigens, CD34↗
PubMed2001

Effect of a short-term in vitro exposure to the marine toxin domoic acid on viability, tumor necrosis factor-alpha, matrix metalloproteinase-9 and superoxide anion release by rat neonatal microglia.

BACKGROUND: The excitatory amino acid domoic acid, a glutamate and kainic acid analog, is the causative agent of amnesic shellfish poisoning in humans. No studies to our knowledge have investigated the potential contribution to short-term neurotoxicity of the brain microglia, a cell type that constitutes circa 10% of the total glial population in the brain. We tested the hypothesis that a short-term in vitro exposure to domoic acid, might lead to the activation of rat neonatal microglia and the concomitant release of the putative neurotoxic mediators tumor necrosis factor-alpha (TNF-alpha), matrix metalloproteinases-2 and-9 (MMP-2 and -9) and superoxide anion (O2-). RESULTS: In vitro, domoic acid [10 microM-1 mM] was significantly neurotoxic to primary cerebellar granule neurons. Although neonatal rat microglia expressed ionotropic glutamate GluR4 receptors, exposure during 6 hours to domoic acid [10 microM-1 mM] had no significant effect on viability. By four hours, LPS (10 ng/mL) stimulated an increase in TNF-alpha mRNA and a 2,233 % increase in TNF-alpha protein In contrast, domoic acid (1 mM) induced a slight rise in TNF-alpha expression and a 53 % increase (p < 0.01) of immunoreactive TNF-alpha protein. Furthermore, though less potent than LPS, a 4-hour treatment with domoic acid (1 mM) yielded a 757% (p < 0.01) increase in MMP-9 release, but had no effect on MMP-2. Finally, while PMA (phorbol 12-myristate 13-acetate) stimulated O2- generation was elevated in 6 hour LPS-primed microglia, a similar pretreatment with domoic acid (1 mM) did not prime O2- release. CONCLUSIONS: To our knowledge this is the first experimental evidence that domoic acid, at in vitro concentrations that are toxic to neuronal cells, can trigger a release of statistically significant amounts of TNF-alpha and MMP-9 by brain microglia. These observations are of considerable pathophysiological significance because domoic acid activates rat microglia several days after in vivo administration.

Animals↗
PubMed2001

Cigar risk perceptions in focus groups of urban African American youth.

PURPOSE: To explore cigar use perceptions among urban African American youth. METHODS: A convenience sample (n = 50) of African American volunteer participants, ages 14- 18, participated in six audiotaped focus groups conducted in two California cities. Transcriptions were analyzed using iterative strategies. RESULTS: Most youth believed cigars were harmful to health, yet a disjuncture existed between this abstract belief and the socially embedded understandings revealed in discussions. Some youth felt that cigars were more "natural" and therefore less harmful than cigarettes. For some, that understanding rested on a mistaken assumption that nicotine was an artificial additive not present in cigars. Youth had received little cigar-specific health education. They reported that cigars were easily obtained, noted cigars' social cachet, and drew attention to new brands targeting youth. IMPLICATIONS: Perceptions of risk are not merely interesting "subjective" findings but are important determinants of actual use patterns and may not correlate with abstract beliefs. Recent cigarette brand repositionings, such as Winston's "no additives" campaign, have widely publicized the many substances added to cigarettes. Some youth may take lack of cigar-specific preventive education as an indication that cigars do not contain such substances, including nicotine. Misperceptions about risks of cigar and cigar/marijuana smoking must be addressed through consistent, coordinated, and comprehensive tobacco control efforts for all tobacco products.

Adolescent↗
PubMed2001

Cover arrangements for consultants on leave: an analysis of job descriptions.

There is much ambiguity about consultant leave allowances and arrangements for cover in the National Health Service. We analysed job descriptions for 47 consultant posts advertised in mid-2000. 35 defined a duty rota but only 3 mentioned specific available leave (all different). In 32 there was no mention of cover for colleagues on leave. When a consultant is absent, colleagues tend to provide cover for emergency cases but not for elective admissions, which are managed largely by junior doctors. This arrangement is particularly hazardous in surgical specialties. If elective surgery is to continue when the consultant is absent, arrangements for leave and cover need to be more clearly defined.

Consultants↗
PubMed2000

Enantiospecific synthesis of N-Boc-Adda: a linear approach.

[structure: see text] Synthesis of the unusual amino acid (2S,3S,8S, 9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-4,6-decadienoic acid (Adda), a unit of numerous cyanobacterial toxins, is described. Construction of the target molecule was achieved in 13 steps with an overall yield of 40%. The work is highlighted by a novel one-pot transformation from isoxazolidin-5-one intermediate 6 to the final product, a step that can also be used to form beta-amino acids.

Amino Acids↗
PubMed2000

Polymorphisms of human SP-A, SP-B, and SP-D genes: association of SP-B Thr131Ile with ARDS.

An allele association study of 19 polymorphisms in surfactant proteins SP-A1, SP-A2, SP-B, and SP-D genes in acute respiratory distress syndrome (ARDS) was carried out. Trend-test analysis revealed differences (p < 0.05) in the frequency of alleles for some of the microsatellite markers flanking SP-B, and for one polymorphism (C/T) at nucleotide 1580 [C/T (1580)], within codon 131 (Thr131Ile) of the SP-B gene. The latter determines the presence or absence of a potential N-linked glycosylation site. Multivariate analysis revealed significant differences only for the C/T (1580) polymorphism. When the ARDS population was divided into subgroups, idiopathic (i.e., pneumonia, etc.) or exogenic (i.e., trauma, etc.), significant differences were observed for the C/T (1580), for the idiopathic ARDS group, and the frequency of the C/C genotype was increased in this group. Based on the odds ratio, the C allele may be viewed as a susceptibility factor for ARDS. Although the expression of both C and T alleles occurs in heterozygous individuals, it is currently not known whether these alleles correspond to similar levels of SP-B protein. These data suggest that SP-B or a linked gene contributes to susceptibility to ARDS.

Alleles↗
PubMed2000

The number of CD34+ cells mobilized into the peripheral blood can predict the quality of subsequent collections.

PBPC were mobilized using a variety of chemotherapy regimens plus G-CSF in a group of 126 consecutive patients. Data are presented that show a close correlation between the number of CD34+ cells mobilized into the peripheral blood (PB) and the number of CD34+ cells subsequently collected by leukapheresis (R = 0.904). On the basis of this correlation, a regression formula was calculated that could give an estimate of the total number of CD34+ cells likely to be collected by leukapheresis from a given number of CD34+ cells per microliter PB. An easy-to-read table has been compiled to show how this type of analysis can be applied to predict the likely dose of CD34+ cells that will be obtained by leukapheresis over a wide range of patient weights.

Antigens, CD34↗
PubMed2000

Personal constructs of male survivors of childhood sexual abuse receiving cognitive analytic therapy.

OBJECTIVE: This study assessed whether male survivors of sexual abuse identified with their abusers rather than their child- or victim-selves and failed to identify with men in general or with their victims, following abusive 'acting out'. Changes in both identification and symptomatology were assessed following cognitive analytic therapy. DESIGN: A patient series within-participants design was used. METHOD: A repertory grid methodology examined four male survivors self-construals before and after therapy. Measures of symptomatic distress, depression, self-esteem and distorted beliefs related to childhood sexual abuse were also obtained. RESULTS: Before therapy, patients showed little identification with the child-selves, men in general and ideal-selves. Two heterosexual patients identified with their abuser(s) whereas another, homosexual, patient negatively identified with his abuser. Patients did not identify with their victims following aggressive 'acting out'. After therapy, identification with the abuser reduced markedly; identification with victim- and ideal-self increased. Depression and distorted beliefs declined. CONCLUSION: Male survivors tend to identify with abusers and disavow their victim-hood. Sexual orientation may predict identification patterns. Cognitive analytic therapy may be a promising method of enabling survivors to integrate their abuse experience and reduce their commitment to the abuser role.

Adult↗
PubMed2000

Pure consciousness: distinct phenomenological and physiological correlates of "consciousness itself".

This paper explores subjective reports and physiological correlates of the experience of "consciousness itself"--self awareness isolated from the processes and objects of experience during Transcendental Meditation practice. Subjectively, this state is characterized by the absence of the very framework (time, space, and body sense) and content (qualities of inner and outer perception) that define waking experiences. Physiologically, this state is distinguished by the presence of apneustic breathing, autonomic orienting at the onset of breath changes, and increases in the frequency of peak EEG power. A model, called the junction point model, is presented that integrates pure consciousness with waking, dreaming, or sleeping. It could provide a structure to generate a coherent program of research to test the full range of consciousness and so enable us to understand what it means to be fully human.

Adult↗
PubMed2000

A comparison of suburban and urban daytime telephone triage calls.

OBJECTIVE: To compare daytime nurse telephone triage calls received by a suburban practice with those received by a hospital-based, inner-city pediatric practice. METHODS: A research assistant, listening simultaneously with triage personnel, prospectively coded all calls received by the nurse triage telephone offices in 2 pediatric practices. Calls were coded the first full, nonholiday week of 3 consecutive summer and 3 consecutive winter months, alternating morning and afternoon sessions. One practice was suburban and had almost all commercially insured patients; the other was hospital-based, in an inner-city, and consisted mostly of patients with Medicaid coverage or no health insurance. RESULTS: A total of 901 calls were triaged in the suburban practice (SP) and 768 in the urban practice (UP). The chief complaints of calls regarding medical problems were similar at both sites. Difficulties with language were noted less often in SP compared with UP (1% vs 17%). The reason for the calls differed by site: medical problem relating to illness or injury (SP 55% vs UP 40%); social issue (SP 1% vs UP 9%); documentation request (SP 2% vs UP 7%); request for laboratory work (SP.3% vs UP 4%); and well child advice (SP 9% vs UP 5%). The disposition of calls also differed by site: telephone advice was offered significantly more in SP than in UP (32% vs 20%); fewer calls required the need for the medical record in SP than in UP (2% vs 12%). CONCLUSIONS: Calls received by a daytime nurse telephone triage office in an affluent SP and a UP are similar in regard to medical problems. Training programs can feasibly prepare physicians and nurses for both kinds of practice settings. The urban site received more calls affected by language and social issues. This could have administrative implications for staffing ratios, language skills of staff and knowledge of available support services.

Child↗
PubMed1999

Pure Consciousness: Distinct Phenomenological and Physiological Correlates of "Consciousness Itself"

This paper explores subjective reports and physiological correlates of the experience of "consciousness itself" - self awareness isolated from the processes and objects of experience during Transcendental Meditation practice. Subjectively, this state is characterized by the absence of the very framework (time, space, and body sense) and content (qualities of inner and outer perception) that define waking experiences. Physiologically, this state is distinguished by the presence of apneustic breathing, autonomic orienting at the onset of breath changes, and increases in the frequency of peak EEG power. A model, called the junction point model, is presented that integrates pure consciousness with waking, dreaming, or sleeping. It could provide a structure to generate a coherent program of research to test the full range of consciousness and so enable us to understand what it means to be fully human.

Journal Article↗