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M Parsons

Publications and source records attributed to M Parsons.

160 records · Page 9Linked to original sources
PubMedDate not supplied

Active transport of 2-deoxy-D-glucose in Trypanosoma brucei procyclic forms.

The characteristics of glucose transport by procyclic forms of Trypanosoma brucei were examined in a rapid transport assay using the glucose analogue 2-deoxyglucose. In contrast to bloodforms where the Km for 2-deoxyglucose transport is about 1 mM, procyclic forms have a Km of about 38 microM. Procyclic forms show temperature-dependent, saturable import, and import of 2-deoxyglucose is competitive with glucose and mannose. Unlike the bloodforms which employ facilitated diffusion, the procyclic forms actively transport glucose. Use of inhibitors and ionophores suggests that a protonmotive force is required for glucose transport in procyclic forms. Unlike the human erythrocyte glucose transporter, the glucose transporter of the T. brucei procyclic form is relatively insensitive to inhibition by cytocholasin B.

Animals↗
PubMedDate not supplied

Chest pain in children: diagnosis through history and physical examination.

INTRODUCTION: Chest pain is a common complaint in the pediatric age group and can be a physically and emotionally distressing symptom. Although chest pain in children rarely indicates serious cardiac problems, chest pain is perceived as "heart pain" to most children and their families and presents a diagnostic challenge to health care providers. METHODS: A prospective study was conducted to identify specific factors in history taking and physical examination that permit accurate diagnosis of the cause of pediatric chest pain. Fifty children (ages 5-21 years; mean, 13 years), referred to the cardiology clinic with the chief complaint of chest pain, underwent systematic history taking, physical examination, and electrocardiogram testing. RESULTS: The following diagnoses were made: 38 children (76%) had musculoskeletal/costochondral chest pain, 6 children (12%) had exercise-induced asthma, 4 children (8%) had chest pain resulting from gastrointestinal causes, and 2 children (4%) had chest pain resulting from psychogenic causes. DISCUSSION: All the children in this study had noncardiac causes of their chest pain. This finding supports previous research suggesting that chest pain in children is rarely of cardiac origin. This article reviews the causes of pediatric chest pain and suggests an approach to its evaluation and management.

Adolescent↗
PubMedDate not supplied

Raspberry leaf in pregnancy: its safety and efficacy in labor.

OBJECTIVE: Many women consume the raspberry leaf herb during their pregnancies in the belief that it shortens labor and makes labor "easier." METHODOLOGY: Because of the paucity of research regarding this herb, particularly in relation to pregnancy and birth, the authors undertook a double-blind, randomized, placebo-controlled trial. The sample consisted of 192 low-risk, nulliparous women who birthed their babies between May 1999 and February 2000 at a large tertiary-level hospital in Sydney, Australia. The aim of the study was to identify the effect and safety of raspberry leaf tablets (2 x 1.2 g per day), consumed from 32 weeks' gestation until labor, on labor and birth outcomes. RESULTS: Raspberry leaf, consumed in tablet form, was found to cause no adverse effects for mother or baby, but contrary to popular belief, did not shorten the first stage of labor. The only clinically significant findings were a shortening of the second stage of labor (mean difference = 9.59 minutes) and a lower rate of forceps deliveries between the treatment group and the control group (19.3% vs. 30.4%). No significant relationship was found between tablet consumption and birth outcomes. CONCLUSION: The lack of significant differences between the groups on measures expected to demonstrate the effect of raspberry leaf ingestion during pregnancy on labor prompted consideration of the issue of effectiveness of dosage level. Suggestions for further research are offered.

Double-Blind Method↗
PubMedDate not supplied

Sequences homologous to variant antigen mRNA spliced leader in Trypanosomatidae which do not undergo antigenic variation.

Trypanosomes which parasitize mammals have evolved mechanisms to evade immune attack, such as the occupation of 'safe' intracellular sites (for example, Trypanosoma cruzi), or antigenic variation, exemplified by the salivarian trypanosomes (for example, Trypanosoma brucei). Antigenic variation is mediated by sequential expression of single variant surface glycoprotein (VSG) genes, and often involves transposition of the active gene. Every VSG transcript examined shares the same 5' terminal 35-nucleotide leader sequence. In T. brucei, this leader is encoded within a 1.4-kilobase unit tandemly reiterated to form a large array. It is hypothesized that this array is distantly linked to the expressed VSG gene and functions as a multiple promoter of VSG gene transcription, restricting transcription to that gene which, through genomic rearrangement, is placed downstream from the array. Leader and structural gene sequences are presumably juxtaposed by RNA splicing. Here we show that several trypanosomatids, both those which undergo antigenic variation (Trypanosoma congolense and Trypanosoma vivax) and those which do not (T. cruzi and Leptomonas collosoma), contain reiterated sequences homologous to the T. brucei spliced leader (SL). These results suggest that the SL, although utilized in VSG gene expression, is an ancestral sequence also used in the expression of other trypanosomatid genes.

Animals↗
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Expression of a minichromosomal variant surface glycoprotein gene in Trypanosoma brucei.

African trypanosomes contain numerous variant surface glycoprotein (VSG) genes, but express only one at a time. When different VSG genes are activated by gene duplicative or non-duplicative mechanisms, antigenic variation occurs. Although transcriptionally inactive VSG genes can have either an intra-chromosomal or a telomeric location, all expressed VSG genes so far examined are telomeric. Some VSG genes are located on minichromosomes of approximately 100 kilobases (kb), but all those thus far described are transcriptionally inactive. We have found that the single copy of the IsTat 1.1 VSG gene in the IsTaR 1 serodeme has a telomeric location on a minichromosome when inactive. When it is activated, it is not duplicated and remains on a minichromosome. These data indicate that minichromosomes contain or can acquire all the DNA sequences necessary in cis for VSG gene expression and antigenic switching. Of several sequences associated with expressed VSG genes or their transcripts, only the 76-base pair (bp) repeat element was found in minichromosomal DNA. Variant antigenic types (VATs) which occurred immediately before and after VAT-1, expressed VSG genes located on larger chromosomes. Thus, different chromosomes can act as VSG gene expression sites.

Animals↗
PubMedDate not supplied

Individualized enhancement programs for nurses that promote competency.

Working in a cost-conscious health care environment changes the accessibility to conferences, workshops and other continuing education offerings. Educators, employers and individual nurses are compelled to be innovative in their approach to maintaining competency through continuing education (CE). Greater emphasis must be placed on effectively matching CE programs with carefully targeted learning needs. This article illustrates a four-phase approach to an individualized enhancement program that incorporates job expectations and competencies. The phases are: 1) completing a needs assessment, 2) defining learning objectives, 3) assessing available learning resources, and 4) evaluating the CE experience.

Clinical Competence↗
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Improving nursing care through mentored research: a paper within a paper.

In 1995 Western Sydney Area Health Service (WSAHS) and University of Western Sydney Nepean (UWSN) entered a strategic alliance to develop a nursing research culture in Western Sydney. As a result, the WSAHS/UWSN Professorial Nursing Unit (PNU) was established in 1996: Its mandate was to develop a variety of strategies to promote a nursing research culture in the area. One of these strategies was to encourage mentored research projects between personnel in the PNU and inexperienced clinical nurses. This paper describes one such project. In addition, it contextualizes the study in relevant literature relating to mentored research and outlines both the issues and the benefits associated with such projects.

Attitude to Health↗
PubMedDate not supplied

Measurement of safe sex behavior in adolescents and young adults.

The aim of this project was to develop an instrument to measure use of safe sex practices among adolescents and to conduct initial evaluation of the psychometric properties of the instrument. The Safe Sex Behavior Questionnaire (SSBQ) was designed to measure the frequency of use of safe sex practices and was assessed for content validity, reliability, and construct validity through a series of tests. The content validity index computed for the SSBQ was 98%. Initial reliability computed for sums of items of the total scale was .82 among 89 college freshmen. Using a second sample of 531 subjects, the SSBQ was factor-analyzed separately for males and females and five similar factors emerged for each gender. Reliability coefficients for sums of salient items for each factor ranged from .52 to .85. Using a third sample of 174 subjects, construct validity was assessed by correlating the SSBQ with measures of general assertiveness and general risk-taking. The resulting correlations were appreciable and in the predicted directions, thus providing support for the construct validity of the instrument.

Acquired Immunodeficiency Syndrome↗