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Biomedical subjects

P Arthur

Publications and source records attributed to P Arthur.

31 records · Page 2Linked to original sources
PubMed1995

Vitamin A supplementation, morbidity, and serum acute-phase proteins in young Ghanaian children.

The association of vitamin A supplementation with concentrations of positive acute-phase proteins in the serum was investigated in the Child Health Study of the Ghana Vitamin A Supplementation Trials, a randomized, controlled trial of the effect of vitamin A on morbidity in children aged < 5 y. Mean serum concentrations of alpha 1-acid glycoprotein, serum amyloid A, and C-reactive protein did not differ overall between the vitamin A-supplemented and placebo-treated groups. Treatment groups were then subdivided according to what symptoms children had experienced in the week before blood sampling. Acute-phase-protein responses to fever and cough were not affected by vitamin A supplementation. There was a tendency for vitamin A-supplemented children, but not placebo children, to have elevated acute-phase proteins in association with reported vomiting or severe diarrhea. The failure of unsupplemented children to mount an acute-phase response may have contributed to their increased morbidity from gastrointestinal symptoms.

Acute-Phase Proteins↗
PubMed1995

Heart and arterial disease risk factor levels in the Scottish workforce: cross-sectional study of risk factor levels. The SHARP Committee. Scottish Heart and Arterial Disease Risk Prevention.

Between 1991-93 a specially trained team of nurses screened 19,435 subjects from various workforces in different regions of Scotland to identify cardiovascular disease risk factor levels in the Scottish working population. The regions visited provided a wide geographical spread. Name, age, occupation, social class, personal and family history of cardiovascular disease were recorded along with consumption of tobacco, alcohol and salt. Height and weight were measured and Body Mass Index (BMI) calculated; systolic (SBP) and diastolic (DBP) blood pressure, blood glucose and blood cholesterol were also measured. The proportion of social class I-IV in men studied was 49, 22, 22, and 7% respectively and in women 28, 29, 39 and 5%. Fifty two per cent of men and 61% of women had never smoked and 24% of men and 17% of women had previously stopped smoking. Twenty one per cent of both sexes were still smoking. Eighteen per cent of men drank more than 21 units of alcohol per week and 3.4% of women drank more than 14 units per week. Mean values of SBP and DBP increased with age and the percentage with hypertension (> or = 148/90 mm Hg) in men and women was 5% and 24% respectively. Mean BMI was slightly higher in men than women (25.3 & 24.5 respectively) and there was a significant (p < 0.01) rise in BMI with age in both sexes. Forty six per cent of men and 32% of women were classified as overweight (BMI > 25) while 9% of men and 9% of women were classified as obese (BMI > 30).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Child morbidity and mortality following vitamin A supplementation in Ghana: time since dosing, number of doses, and time of year.

OBJECTIVES: The impact of large-dose vitamin A supplementation given at intervals of 4 months on child mortality and morbidity was examined according to the time interval since dosing, number of doses received previously, and time of year. METHODS: Two double-blind, randomized, placebo-controlled trials of large doses of vitamin A administered at intervals of 4 months were conducted in adjacent populations in northern Ghana. RESULTS: While vitamin A supplementation significantly reduced the overall incidence of severe illnesses (especially diarrhea with dehydration), clinic attendances, hospital admissions, and mortality, there was no evidence that the impact of each dose of vitamin A was related to the number of doses the child had received previously. There was no evidence that the effectiveness of the supplement waned over the 3 to 5 months between doses. The impact on mortality did not differ significantly by the month in which the supplement had been given. CONCLUSIONS: In the study population, there was no evidence that an interval between doses of less than 4 months would have had a greater impact on severe morbidity or mortality, and the effectiveness of supplementation did not vary by time of year.

Child↗
PubMed1995

Potential interventions for the prevention of childhood pneumonia in developing countries: a systematic review.

This article describes the background and framework for a systematic review of potential interventions for preventing pneumonia among under-5-year-olds in developing countries. Twenty-eight intervention areas are identified in six groups -- immunization, case management/chemoprophylaxis of high-risk children, improving nutrition, reducing environmental pollution, reducing transmission of pathogens, and improving child care practices. Calculation of the potential impacts is illustrated and the expected outcomes are also described.

Child Welfare↗
PubMed1994

Incorporation of norleucine at methionine positions in recombinant human macrophage colony stimulating factor (M-CSF, 4-153) expressed in Escherichia coli: structural analysis.

Expression of the 17.5-kDa truncated form of human recombinant macrophage colony stimulating factor (rM-CSF, 4-153) in Escherichia coli is complicated by the replacement of methionine residues by norleucine. In order to detect and quantitate this mistranslational event, the intact and the S-carboxyamidomethylated proteins were analyzed by amino acid analysis, automated Edman amino acid sequencing, and electrospray mass spectrometry. In addition, the endoproteinase Glu-C generated peptides were subjected to amino acid sequencing, high-performance liquid chromatography, and electrospray ionization mass spectrometry. The extent of norleucine substitution in different batches of rM-CSF varied between 0% and 20%. The relative instability of methionine residues needs to be considered when calculating the extent of norleucine substitution at methionine positions. The mass spectrometry of the intact rM-CSF allowed for examination of the distribution of multiply substituted methionine to norleucine species, and it enabled detection and quantitation of the norleucine incorporation down to the approximately 3% level. Selective ion chromatograms of molecular ions of interest obtained in reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry of proteolytic fragments offered a reliable and fast method of detection and quantitation of norleucine-containing peptides. Norleucine residues were uniformly distributed among all four methionine positions (10, 27, 61, and 65). A substitution of methionine by its structural norleucine analog does not have any effect on the activity of the refolded rM-CSF dimers.

Amino Acid Sequence↗
PubMed1994

MECHANICAL PERFORMANCE OF AN IN SITU PERFUSED HEART FROM THE TURTLE CHRYSEMYS SCRIPTA DURING NORMOXIA AND ANOXIA AT 5 C AND 15 C

We developed an in situ perfused turtle (Chrysemys scripta) heart preparation to study its intrinsic mechanical properties at 5&deg;C and 15&deg;C using normoxic and anoxic perfusion conditions. The in situ preparation proved durable and stable. At 15&deg;C and a spontaneous heart rate of 23.4 beats min-1, maximum stroke volume was 2.54 ml kg-1 body mass, maximum cardiac output was 62.5 ml min-1 kg-1 and maximum cardiac myocardial power output was 1.50 mW g-1 ventricular mass. There was good agreement between these values and those previously obtained in vivo. Furthermore, since the maximum stroke volume observed here was numerically equivalent to that observed in ventilating C. scripta in vivo, it seems likely that C. scripta has little scope to increase stroke volume to a level much beyond that observed in the resting animal through intrinsic mechanisms alone. The ability of the perfused turtle heart to maintain stroke volume when diastolic afterload was raised (homeometric regulation) was relatively poor. At 5&deg;C, the spontaneous heart rate (8.1 beats min-1) was threefold lower and homeometric regulation was impaired, but maximum stroke volume (2.25 ml kg-1) was not significantly reduced compared with the value at 15&deg;C. The significantly lower maximum values for cardiac output (18.9 ml min-1 kg-1) and power output (0.39 mW g-1 ventricular mass) at 5&deg;C were largely related to pronounced negative chronotropy with only a relatively small negative inotropy. Anoxia had weak negative chronotropic effects and marked negative inotropic effects at both temperatures. Negative inotropy affected pressure development to a greater degree than maximum flow and this difference was more pronounced at 5&deg;C than at 15&deg;C. The maximum anoxic cardiac power output value at 15&deg;C (0.77 mW g-1 ventricular mass) was not that different from values previously obtained for the performance of anoxic rainbow trout and hagfish hearts. In view of this, we conclude that the ability of turtles to overwinter under anoxic conditions depends more on their ability to reduce cardiac work to a level that can be supported through glycolysis than on their cardiac glycolytic potential being exceptional.

Journal Article↗
PubMed1994

Lack of association between vitamin A status and measures of conjunctival epithelial integrity in young children in northern Ghana.

OBJECTIVE: To investigate the association between vitamin A status and conjunctival epithelial function in young children in rural northern Ghana and to consider whether impaired epithelial function was associated with increased measures of systemic infection in these children. DESIGN: Children were selected from the Ghana Vitamin A Supplementation Trials' Child Health Study, a randomized, double-blind, placebo-controlled trial of the effect of vitamin A supplementation on morbidity. Treatment group and serum retinol concentrations were used as measures of vitamin A status, conjunctival impression cytology and tear IgA concentrations as measures of conjunctival epithelial integrity, and serum immunoglobulin and alpha 1-acid glycoprotein concentrations as indicators of chronic or acute systemic infection. SUBJECTS: Children 13-64 months old. INTERVENTION: 60 mg retinol as retinyl palmitate every 4 months for 1 year. RESULTS: Vitamin A status was not significantly associated with epithelial integrity nor with measures of systemic infection. Impaired conjunctival epithelial integrity was also not associated with increased systemic infection. CONCLUSIONS: There was no evidence for a major role of improved epithelial integrity and function on the biochemical indices of chronic or acute systemic infection after vitamin A supplementation. These data support the observations in the main study that vitamin A supplementation did not improve conjunctival impression cytology nor decrease the prevalence of most morbidity symptoms.

Child Nutritional Physiological Phenomena↗
PubMed1993

Influence of morbidity on serum retinol of children in a community-based study in northern Ghana.

Serum retinol concentrations decrease during illness and thus may not accurately reflect the vitamin A status of populations with a high prevalence of illness. To quantify the contribution of illness to low serum retinol in a field study of children aged 6-59 mo in northern Ghana, serum retinol values were compared with two indicators of recent illness; symptoms reported by parents and acute-phase protein concentrations in serum. Serum retinol was not associated with symptoms of illness but showed a significant negative correlation with both alpha 1-acid glycoprotein (AGP) and serum amyloid A (SAA). Elevated AGP was associated with a 24% decrease in mean serum retinol. A large proportion of asymptomatic children had elevated AGP or SAA concentrations, suggesting that subclinical infections may have had important effects on serum retinol. A significant negative correlation between malaria parasite density and serum retinol indicated that malaria may have been one of the subclinical infections responsible. Measurement of AGP may improve interpretation of serum retinol data from populations with a high prevalence of morbidity.

Child, Preschool↗
PubMed1989

A mouse hybrid cell line that supports gene expression from a variety of promoters in amplifiable vectors.

A hybrid cell line was constructed by fusion of mouse L-cells with an NIH3T3 cell line derivative containing a hybrid gene consisting of the mouse immunoglobulin kappa (IgK) variable gene promoter linked to the Escherichia coli gpt gene. Such hybrids grew to a much higher density compared to either of the parental cell lines. The utility of this cell line as a host to express foreign genes was tested by the expression of TGF-beta cDNA using the cytomegalovirus promoter. The vector also contained the human dihydrofolate reductase (DHFR) gene driven by SV40 early promoter, to allow for the amplification of the transfected gene. Initial transformants, selected at 100 nM methotrexate (MTX), were subsequently selected for resistance to a higher concentration of MTX (2 microM). Such clones expressed an increased level of TGF-beta when compared to the initial transformants. Both the initial transformants and the clones with the amplified DHFR gene produced TGF-beta in an acid-activatable precursor form. This mouse hybrid host cell line also allowed the expression of foreign genes cloned in an eukaryotic expression vector with the mouse IgK variable region promoter and human growth hormone as the reporter gene, whereas such vectors did not function in CHO cells. The mouse hybrid cell line was also found to be capable of being used with a broad range of promoters.

Animals↗
PubMedDate not supplied

Patterns of malaria morbidity and mortality in children in northern Ghana.

A malaria prevalence survey was carried out in young children in northern Ghana between October 1990 and September 1991, in an area with continuous mortality and morbidity surveillance. There was marked seasonal variation in malaria deaths, reported fevers, parasite rates and mean parasite densities, with parasite rates reaching 85-94% in the wet season. The monthly numbers of malaria deaths were highly correlated with rainfall in the previous 2 months (r = 0.90, P < 0.001). Parasite rates were highest in the oldest children (5-7 years), but parasite densities and rates of febrile illness were highest in those 6-11 months old. Haemoglobin levels were also at their lowest in this age group. The predominant species, Plasmodium falciparum, was present in 71% of all blood films. Febrile illness was well recognized by mothers, but it was not possible to construct a simple clinical diagnostic algorithm which would identify even 50% of children with high levels of malaria parasitaemia (> or = 4000 parasites/microL). Malariometric indicators appear to have changed little in this area since a previous survey in 1955.

Age Factors↗