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Biomedical subjects

M Charles

Publications and source records attributed to M Charles.

At least 19 recordsLinked to original sources
PubMed2001

Polar targeting of Shigella virulence factor IcsA in Enterobacteriacae and Vibrio.

Asymmetric localization is key to the proper function of certain prokaryotic proteins important to virulence, chemotaxis, cell division, development, motility, and adhesion. Shigella IcsA is localized to the old pole of the bacterium, where it mediates assembly of an actin tail inside infected mammalian cells. IcsA (VirG) is essential to Shigella intracellular motility and virulence. We used translational fusions between portions of IcsA and the green fluorescent protein (GFP) to determine the regions of IcsA that are necessary and sufficient for its targeting to the bacterial old pole. An IcsA-GFP fusion that lacks a signal peptide localized to the old pole, indicating that signal peptide-mediated secretion is not required for polar localization. Two regions within IcsA were required for localization of an IcsA-GFP fusion to the old pole. Further characterization of these regions indicated that amino acids 1-104 and 507-620 were each independently sufficient for polar localization. Finally, when expressed in Escherichia coli, Salmonella typhimurium, Yersinia pseudotuberculosis, and Vibrio cholerae, each of the two targeting regions localized to the pole, indicating that the mechanism of polar targeting used by IcsA is present generally among Enterobacteriacae and Vibrio.

Amino Acid Sequence↗
PubMed2001

Nonphysical touch: modes of containment and communication within the analytic process.

Psychoanalysis has struggled with issues of touching and being touched, and of holding and being held, since Freud's early essays toward "taking hold" of elusive thoughts through various means. More recently, observations of early dyadic interchanges between caretaker and child have illuminated how facets of the analytic process, such as the quality of gaze, tone, or empathic resonance, affect feelings of "being held" within the object world. These studies interplay with other analytic depictions and the work of affect theorists to show how meanings become represented and manifested over time through verbal versus nonverbal means. The author uses this literature to explore how our capacity to receive and transmit information cross-modally creates an interpenetration of meanings between self and other in the absence of actual physical contact. Clinical illustrations explore some of the meanings and uses of nonphysical modes of touch within the analytic environment.

Communication↗
PubMed2001

Auto-sensuous shapes: prototypes for creative forms.

The author looks at some of the more normative, adaptive, and creative aspects of what have been called 'autistic' or 'auto-sensuous' shapes by Tustin and others. She explores the construct from several frameworks, including the literature on early sensory experience and that on the empathic attunement between infant and caretaker in which interpersonal rhythms and meanings are built. The views of Bion and Matte-Blanco are utilized to help explore the processes by which meaning is created from experience, while the works of Segal and Milner are used to focus more explicitly on the role of symbol formation in the creative process. Finally, it is suggested that these auto-sensuous shapes can become prototypes for creative endeavours, including the creative process we call psychoanalysis. The author uses examples from her own experience in deriving pattern from basic sensory experience, toward the creation of poetry, drawings, and the establishment of attunement and 'meaning-making' within the analytic setting.

Child↗
PubMed2001

Further manipulation of the stop-signal task: developmental changes in the ability to inhibit responding with longer stop-signal delays.

The stop-signal task, a measure of inhibitory control, was further modified in order to examine its suitability as a task for very young children. A previous study (Carver et al., 2001) showed that it can be successfully adapted for use with primary school-aged children. The present study manipulated the presentation of the signal to inhibit responding and found that this improved the likelihood of responding. A pre-primary school group of children (< 5 years, 6 months), a young primary school group (5 years, 7 months to 7 years, 6 months), and a mid-primary school group (7 years, 7 months to 9 years, 6 months) participated in the study. The results emphasize the pre- and early school years as a sensitive time for the development of inhibitory skills. Measures of inhibitory control must therefore be age-appropriate and sensitive to these early developmental changes.

Child↗
PubMed2001

Age related changes in inhibitory control as measured by stop signal task performance.

A modified version of the stop signal task (suitable for use with very young children) was administered to a pre primary school group of children (<5 years, 6 months); a young primary group (5 years, 7 months to 7 years, 6 months); a mid primary group (7 years, 7 months to 9 years, 6 months) and a group of adults. Significant age differences in the ability to inhibit responding were found. These results highlight the need for measures of response inhibition which are appropriate for use with very young children, when the first signs of inhibitory skills are emerging. It is also imperative that such measures allow the assessment of skills across a broad range of age groups in order to comprehensively monitor their development.

Adolescent↗
PubMed2000

Perceived expressed emotion in the siblings and parents of hospitalized patients with anorexia nervosa.

OBJECTIVE: The present study investigated the relationship between the level of perceived Expressed Emotion (EE) of the siblings and parents of patients hospitalized with anorexia nervosa and its effect on weight gain and psychological functioning. METHOD: The Level of Expressed Emotion (LEE) Scale was administered on admission to 19 patients with anorexia nervosa who completed the LEE three times so as to identify their perceptions of their relationship with their closest age sibling, mother, and father. They were also required to complete the Eating Disorder Inventory 2 (EDI-2). Patients' closest age sibling completed the Family Attitude Scale (FAS). The patients' body mass index (BMI) was calculated 6 weeks later, and the EDI-2 readministered. RESULTS: Perceived EE was not predictive of BMI change after 6 weeks of hospitalization. A composite perceived family EE score was a significant predictor of change on the Interpersonal Distrust, Maturity Fears, and Perfectionism subscales of the EDI-2. DISCUSSION: These findings suggest that patients' perceptions of their relationships with their closest aged sibling, mother, and father are poor predictors of weight gain and improvement in psychological functioning following 6 weeks of inpatient treatment.

Adult↗
PubMed2000

The effect of body dissatisfaction on women's perceptions of female celebrities.

OBJECTIVE: Research suggests that media exposure causes some women to feel heightened dissatisfaction with their body shape. This study attempts to determine which women are effected as such, by investigating how women feel about their own bodies and how this effects their perceptions of female celebrities in the media. METHOD: Undergraduate females (n = 116) were shown one accurate and six distorted photographs of thin and heavy female celebrities. Each distorted photograph made the celebrity appear thinner or heavier than actuality. Participants chose which photograph portrayed each celebrity's true body shape. Body shape concerns were measured by the Body Shape Questionnaire. RESULTS: Women concerned about their body shape judged thin celebrities as thinner than actuality, whereas unconcerned women judged them accurately. Both groups judged heavy celebrities as heavier than actuality. DISCUSSION: Results suggest certain women are effected by media exposure due to their own perception of females in the media. Prevention strategies, and the media's role in body dissatisfaction and dieting disorders, are discussed.

Adolescent↗
PubMed2000

Focus group discussions in medical research.

Qualitative research methods have recently started to gain popularity in social and health sciences for determining a more holistic view of peoples' perceptions about health. Focus group discussions are frequently used to obtain perspectives and attitudes of people about issues, seek explanations for behavior, triangulate data obtained through other qualitative methods and generate hypotheses. To facilitate clinicians to comprehend the use of focus group methodology in the clinical field, the meaning, purpose, advantages, limitations and quality assurance measures of focus group discussions are described. The general requirements and the method for conducting focus groups are briefly explained. In addition, key issues that could be addressed by focus group methodology have also been highlighted.

Focus Groups↗
PubMed2000

Quantitative vs qualitative research methods.

Quantitative methods have been widely used because of the fact that things that can be measured or counted gain scientific credibility over the unmeasurable. But the extent of biological abnormality, severity, consequences and the impact of illness cannot be satisfactorily captured and answered by the quantitative research alone. In such situations qualitative methods take a holistic perspective preserving the complexities of human behavior by addressing the "why" and "how" questions. In this paper an attempt has been made to highlight the strengths and weaknesses of both the methods and also that a balanced mix of both qualitative as well as quantitative methods yield the most valid and reliable results.

Data Collection↗
PubMed2000

Potent aroma compounds of two red wine vinegars.

Gas chromatography olfactometry (GCO) was used to determine key aroma compounds of two red wine vinegars. Sensory analysis was performed to choose the best neutralization agent of acetic acid (NaOH or MgO) and to test representativeness of four extracts obtained by different methods (dichloromethane extraction, XAD-2, mixture of XAD-2 and XAD-7, and Extrelut resins extraction). Neutralization with NaOH followed by dichloromethane extraction was selected to extract volatile compounds of vinegars. Key odorant compounds were determined by GCO based on detection frequency with 13 people. In the two red wine vinegars, 13 odors were perceived by at least 70% of the panelists, and 8 compounds among the 13 were identified: acetic acid, 3-methylbutyric acid, 2-phenyl-1-ethanol, 2, 3-butanedione, butyric acid, 2-methylbutyric acid, mixture of 2- and 3-methyl-1-butanol, and two newly identified compounds in vinegar, 3-hydroxy-2-pentanone and 3-(methylthio)-1-propanal. Quantification of all the volatile compounds was performed by GC-FID, and 10 other compounds were identified for the first time in wine vinegar.

Acetic Acid↗
PubMed2000

Flavor release from salad dressings: sensory and physicochemical approaches in relation with the structure.

The effect of process and formulation on sensory perception and flavor release was investigated on salad dressing models. Oil/vinegar emulsions (phi = 0.5, droplet size > 10 microm) with thickeners and a whey protein concentrate were prepared with different fat droplet sizes and different distributions of fat droplet size. The effect of the amount of emulsifier was also tested. Sensory profile analysis was performed by a trained panel and flavor release quantified by dynamic headspace analysis. When the droplet size is increased, the lemon smell and citrus aroma significantly increase, whereas the egg note, mustard, and butter aroma significantly decrease. The concentrations of alcohols and acids significantly increase when droplet size increases, whereas those of other compounds such as limonene or benzaldehyde significantly decrease. The dispersion of the droplet size has a small effect on flavor perception, and the effect of the increase of the amount of emulsifier is noticed only by instrumental analysis.

Dietary Fats↗
PubMed1999

Functional analysis of a rickettsial OmpA homology domain of Shigella flexneri icsA.

Shigella flexneri is a gram-negative bacterium that causes diarrhea and dysentery by invasion and spread through the colonic epithelium. Bacteria spread by assembling actin and other cytoskeletal proteins of the host into "actin tails" at the bacterial pole; actin tail assembly provides the force required to move bacteria through the cell cytoplasm and into adjacent cells. The 120-kDa S. flexneri outer membrane protein IcsA is essential for actin assembly. IcsA is anchored in the outer membrane by a carboxy-terminal domain (the beta domain), such that the amino-terminal 706 amino acid residues (the alpha domain) are exposed on the exterior of the bacillus. The alpha domain is therefore likely to contain the domains that are important to interactions with host factors. We identify and characterize a domain of IcsA within the alpha domain that bears significant sequence similarity to two repeated domains of rickettsial OmpA, which has been implicated in rickettsial actin tail formation. Strains of S. flexneri and Escherichia coli that carry derivatives of IcsA containing deletions within this domain display loss of actin recruitment and increased accessibility to IcsA-specific antibody on the surface of intracytoplasmic bacteria. However, site-directed mutagenesis of charged residues within this domain results in actin assembly that is indistinguishable from that of the wild type, and in vitro competition of a polypeptide of this domain fused to glutathione S-transferase did not alter the motility of the wild-type construct. Taken together, our data suggest that the rickettsial homology domain of IcsA is required for the proper conformation of IcsA and that its disruption leads to loss of interactions of other IcsA domains within the amino terminus with host cytoskeletal proteins.

Amino Acid Sequence↗
PubMed1999

The Piggle: confrontations with non-existence in childhood.

The author interweaves pieces from D. W. Winnicott's 'The Piggle: An Account of the Psychoanalytic Treatment of a Little Girl' with her own experiences and case material, to explore how confrontations with existence/non-existence can become terrifying realities that overwhelm the child's resources. In the pages of 'The Piggle', we can see a young child 'playing' with the unfathomable notions of beginnings and endings in the wake of the birth of a sibling, which also heralds the death of the extant mother/child relationship. In the case material these issues are explored from the perspective of an adult who had been unable to resolve them without great loss of self. In both cases, parental failures impeded the child's ability to integrate his or her experiences. The work of Matte-Blanco provides a useful terminology for understanding condensations and equivalences in the material; as affect intensifies, the rules of conventional logic recede, and sameness threatens to annihilate distinctions between good and bad, or self and other. Containing these dichotomies within the analytic setting facilitates their integration, in a movement from the fragmentation of the paranoid-schizoid position towards the reconciliation and renunciation of the depressive position.

Child↗
PubMed1998

Mineral composition of non-conventional leafy vegetables.

Six non-conventional leafy vegetables consumed largely by the rural populace of Nigeria were analyzed for mineral composition. Mineral contents appeared to be dependent on the type of vegetables. Amaranthus spinosus and Adansonia digitata leaves contained the highest level of iron (38.4 mg/100 g and 30.6 mg/100 g dw, respectively). These values are low compared to those for common Nigerian vegetables but higher than those for other food sources. All the vegetables contained high levels of calcium compared to common vegetables, thus they could be a rich source of this mineral. Microelement content of the leaves varied appreciably. Zinc content was highest in Moringa oleifera, Adansonia digitata and Cassia tora leaves (25.5 mg/100 g, 22.4 mg/100 g and 20.9 mg/100 g dw, respectively) while the manganese content was comparatively higher in Colocasia esculenta. The concentrations of the mineral elements in the vegetables per serving portion are presented and these values indicate that the local vegetables could be valuable and important contributors in the diets of the rural and urban people of Nigeria. The mean daily intake of P, Mg, Ca, Fe, Cu and Zn were lower than their recommended dietary allowances (RDAs). However, the manganese daily intake was found not to differ significantly (p = 0.05) from the RDA value.

Calcium↗