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P Willcox

Publications and source records attributed to P Willcox.

At least 19 recordsLinked to original sources
PubMed1999

Transition from paediatric to adult care for persons with cystic fibrosis: patient and parent perspectives.

OBJECTIVES: To gauge the perspectives of adolescents and adults with cystic fibrosis (CF) and their parents regarding the transition from paediatric to adult-oriented health care. METHODS: Cross-sectional survey using an anonymous, semi-structured questionnaire. The study population consisted of adolescents and adults attending a paediatric and an adult CF clinic in Cape Town, South Africa and their parents. RESULTS: Forty-seven of the 61 subjects completed the questionnaire (response rate 77%). Autonomy in health care was 'extremely important' to most persons with CF. Transfer at the age of 16-18 years of age was the preferred option for most respondents. Whereas over 80% of parents felt their children needed more CF-related information, only 38% of adolescents expressed this need (P < 0.05). Adolescents also reported little need for general health information. More than 80% of respondents were 'unsure' about transfer. Over 90% felt that a transition clinic would be useful. As viewed by the respondents, its main purpose would be to provide information about the adult clinic and an opportunity to meet the CF doctor in the adult clinic. CONCLUSION: There are significant concerns about the transition process in this population. Given the expressed need for autonomy and a transition clinic, the basis for a smoother transition in the future has been laid.

Adolescent↗
PubMed1998

Differential gene expression in response to adjunctive recombinant human interleukin-2 immunotherapy in multidrug-resistant tuberculosis patients.

Administration of low-dose recombinant human interleukin 2 (rhuIL-2) in combination with multidrug chemotherapy to patients with multidrug-resistant tuberculosis (MDR TB) induces measurable changes in in vitro immune response parameters which are associated with changes in the clinical and bacteriologic status of the patients. To determine the molecular basis of these changes, we have used semiquantitative reverse transcriptase-initiated PCR (RT-PCR) and differential display technology. During rhuIL-2 treatment of MDR TB patients, decreased levels of gamma interferon (IFN-gamma) mRNA in peripheral blood mononuclear cells (PBMC) relative to baseline levels were observed. However, at the site of a delayed-type hypersensitivity (DTH) response to purified protein derivative of tuberculin (PPD), the expression of cellular IFN-gamma and IL-2 mRNAs was increased during rhuIL-2 therapy. Levels of other cytokine mRNAs were not significantly affected by rhuIL-2 administration. Using differential-display RT-PCR, we identified several genes expressed at the DTH skin test site which were up- or down-regulated during rhuIL-2 treatment. Cytochrome oxidase type I mRNA was increased in response to rhuIL-2 therapy relative to baseline levels, as was heterogeneous nuclear ribonuclear protein G mRNA. CD63, clathrin heavy chain, and beta-adaptin mRNAs, all of which encode proteins associated with the endocytic vacuolar pathway of cells, were also differentially regulated by rhuIL-2 administration. The differential effects of IL-2 were confirmed in vitro by using PBMC obtained from PPD-positive individuals stimulated with Mycobacterium tuberculosis and IL-2. The differential expression of genes may provide a surrogate marker for leukocyte activation at a mycobacterial antigen-specific response site and for the development of an enhanced antimicrobial response which may result in improved outcomes in MDR TB patients.

Adult↗
PubMed1997

rhuIL-2 adjunctive therapy in multidrug resistant tuberculosis: a comparison of two treatment regimens and placebo.

SETTING: Low-dose recombinant human interleukin 2 (rhuIL-2) adjunctive immunotherapy in multidrug resistant tuberculosis (MDR-TB) patients. OBJECTIVE: Evaluation of the effects of daily versus pulse-administered rhuIL-2 compared to placebo. DESIGN: MDR-TB patients on best available antituberculous chemotherapy received rhuIL-2 for 30 consecutive days (daily therapy), or for 5 days followed by a 9-day 'rest', for three cycles (pulse therapy). Placebo control patients received diluent. The cumulative total dose of rhuIL-2 given to each patient in either rhuIL-2 treatment group was the same. Patient immunologic, microbiologic, and radiologic responses were compared. RESULTS: The three treatment schedules induced different results. Immune activation was documented in patients receiving daily rhuIL-2 therapy. Numbers of CD25+ and CD56+ cells in the peripheral blood were increased in these patients, but not in patients receiving pulse rhuIL-2 or placebo. In addition, 5/8 (62%) patients receiving daily rhuIL-2 demonstrated reduced or cleared sputum bacterial load while only 2/7 (28%) pulse rhuIL-2 treated and 2/8 (25%) controls showed bacillary clearance. Chest radiographs of 7/12 (58%) patients receiving daily rhuIL-2 indicated significant improvement over 6 weeks. Only 2/9 (22%) pulse rhuIL-2-treated patients and 5/12(42%) placebo controls showed radiologic improvement. CONCLUSION: Daily low dose rhuIL-2 adjunctive treatment stimulates immune activation and may enhance the antimicrobial response in MDR-TB.

Adult↗
PubMed1995

Clinical and immune responses of tuberculosis patients treated with low-dose IL-2 and multidrug therapy.

The immune response to infection with M. tuberculosis depends on cytokine activation of effector cells. We therefore conducted a pilot study of recombinant human interleukin-2 (rhuIL-2) as an adjunct to multidrug therapy (MDT) to evaluate the safety of this approach and to determine whether IL-2 can enhance the cellular immune response in patients with pulmonary tuberculosis (TB). Patients included in this study presented with a wide range of extent and duration of infection, and were grouped into three categories for data analysis: (1) patients with newly diagnosed, acute-stage TB who were just beginning MDT; (2) patients who had received a minimum of 45 days MDT before the start of the study and who had responded to treatment; and (3) patients with multidrug-resistant (MDR) TB who had been on MDT for at least seven months without apparent beneficial clinical response. Twenty patients received 30 days of twice-daily intradermal injections of 12.5 micrograms of IL-2. Patients from all three groups showed improvement of clinical symptoms over the 30-day period of treatment with IL-2 and MDT. Results of direct smear for acid fast bacilli (AFB) demonstrated conversion to sputum-negative following IL-2 and MDT treatment in all newly diagnosed patients and in 5/7 MDR TB patients. (The size of the skin test response to purified protein derivative (PPD) of tuberculin increased during the 30-day IL-2 adjunctive therapy in newly diagnosed patients, but decreased or disappeared in the other two groups of treated patients.) Assays in vitro for phenotype distribution, natural killer (NK) cell activity, frequency of cells proliferating in response to exogenous IL-2, and antigen-induced blastogenesis demonstrated systemic responses to intradermally administered rhuIL-2. Levels of interferon-gamma (IFN-gamma) in plasma, peripheral blood mononuclear cell (PBMC) IFN-gamma mRNA and IFN-gamma mRNA in biopsy of site of skin test response to purified protein derivative (PPD) were highest in those patients with the most acute symptoms at the beginning of the study, and decreased during rhuIL-2 and MDT. IL-2 immunotherapy did not modify levels of mRNA expression for other cytokines. Patients receiving IL-2 did not experience clinical deterioration or significant side effects. These results suggest that IL-2 administration in combination with conventional MDT is safe and may potentiate the antimicrobial cellular immune response to TB.

Adult↗
PubMed1979

Secretion and uptake of beta-N-acetylglucosaminidase by fibroblasts. Effect of chloroquine and mannose 6-phosphate.

The effects of chloroquine and mannose 6-hosphate on the secretion and uptake of the lysosomal enzyme, beta-N-acetylglucosaminidase (EC 3.2.1.30), by human fibroblasts have been compared. There was a reciprocal relationship between intracellular depletion, and extracellular accumulation, of enzyme at chloroquine concentrations ranging from 5 micrometers to 100 micrometers. A loss of enzyme activity from the system (intra- plus extracellular activity) with increasing concentrations of chloroquine was due to inhibition of the beta-N-acetylglucosaminidase. At a concentration of 50 micrometers, chloroquine elicited a three fold increase in the extracellular accumulation of beta-N-acetylglucosaminidase in 24 h whereas the addition of 5 micrometers mannose 6-phosphate (a competitive inhibitor of receptor-mediated uptake) resulted in only a 13% increase. Uptake of beta-N-acetylglucosaminidase by enzyme-deficient fibroblasts was completely inhibited by 5 micrometers mannose 6-phosphate. In the presence of chloroquine there was also no uptake of enzyme, however ther was a marked decrease in the residual activity of the cells. The results suggest that the effect of chloroquine on fibroblasts is to stimulate secretion rather than to inhibit uptake as previously reported. The isoenzyme pattern of the beta-N-acetylglucosaminidase from normal culture medium was compared with that accumulating in the medium following exposure of the cells to 50 micrometers chloroquine. In the presence of chloroquine, there was an increase in the A isoenzyme, however the activity was eluted in a broad peak which probably represents several closely related forms of the enzyme. There was an almost total loss of the A isoenzyme of beta-N-acetylglucosaminidase from fibroblasts cultured in the presence of chloroquine. A small peak of activity eluting at a similar position to the secreted, As, isoenzyme was present in extracts of chloroquine-treated fibroblasts, suggesting that the As isoenzyme is formed and/or stored at a site distinct from the intracellular isoenzyme.

Acetylglucosaminidase↗
PubMed1979

Abortion today.

Explore the source record for details and available documents.

Abortion, Illegal↗
PubMed1979

"Affinity" chromatography of steroid-transforming enzymes with a non-steroidal ligand.

The chromatographic behaviour of an avian oestradiol-17 beta dehydrogenase, the 3(17) beta-hydroxy steroid dehydrogenase from Pseudomonas testosteroni and cortisone reductase from Streptomyces dehydrogenans was studied on columns of p-(phenoxypropoxy)aniline attached to CNBr-activated Sepharose. The ligand was effective in adsorbing the oestradiol dehydrogenase from a partially purified extract of chicken liver, and the cortisone reductase was perferentially retained when mixtures of the three dehydrogenases were applied to columns in 10mM-buffer. Under these conditions the 3(17)beta-hydroxy steroid dehydrogenase was eluted in the front, but was adsorbed in the presence of 3 M-KCl. beta-N-Acetylglucosaminidase present in the liver preparation was not retained by the ligand, whereas lactate dehydrogenase from rabbit muscle was adsorbed in a manner similar to the retention pattern found on affinity chromatography with 2',5'-ADP--Sepharose. The mean overall purification of the oestradiol dehydrogenase was 13-fold, with a mean recovery of 53%. p-(Phenoxypropoxy)aniline offers promise for the purification of steroid-transforming enzymes where elution with substrate or cofactor is not wanted. It is also suggested that the ligand may be of service in the purification of receptors of hormonal steroids.

17-Hydroxysteroid Dehydrogenases↗
PubMed1979

Secretion of beta-N-acetylglucosaminidase isoenzymes by cultured cystic fibrosis fibroblasts.

Secretion of the lysosomal enzyme beta-N-acetylglucosaminidase (EC 3.2.1.30) by normal and cystic fibrosis fibroblasts has been compared. In contrast to an earlier report, no differences were found in either the rate of secretion, or in the molecular forms of the enzyme secreted by normal fibroblast cultures and cultures initiated from patients with cystic fibrosis. The B isoenzyme of beta-N-acetylglucosaminidase from cystic fibrosis fibroblasts was converted to a more negatively charged form during preincubation for 3 h at pH 5.0 and 37 degrees C. The enzyme from normal fibroblasts was unaffected by this treatment.

Acetylglucosaminidase↗
PubMed1978

Secretion of beta-N-acetylglucosaminidase isoenzymes by normal human fibroblasts.

1. Secretion of the lysosomal enzyme beta-N-acetylglucosaminidase (EC 3.2.1.30) by normal human fibroblast cultures was linear with respect to time up to 96h. 2. Two forms of the A isoenzyme of beta-N-acetylglucosaminidase were found in the culture medium. One form was similar to the isoenzyme found in other extracellular fluids, such as plasma and tears, the other resembled the intracellular (lysosomal) enzyme. The presence of the two isoenzymes in the culture medium appears to reflect two distinct secretory processes. 3. It is suggested that plasma acid hydrolases may be destined for incorporation into lysosomes in a manner analogous to that described for the packaging of lysosomal enzymes by fibroblasts.

Acetylglucosaminidase↗
PubMed1978

Separation of beta-N-acetylglucosaminidase isoenzymes from liver and plasma of six mammalian species by DEAE-cellulose chromatography.

1. The beta-N-acetylglucosaminidase (EC 3.2.1.30) activities of human, pig, calf, lamb, rat and rabbit liver and plasma have been investigated. 2. All preparations had maximum activity between pH 4.0 and 4.5 and Km values with the substrate 4-methylumbelliferyl-2-acetamido-2-deoxy-beta-D-glucopyranoside ranged from 0.54 to 2.54 mM. 3. The isoenzyme profiles of liver and plasma beta-N-acetylglucosaminidase activity were compared using DEAE-cellulose chromatography. In all species the major anionic component of liver (beta-N-acetylglucsaminidase A) was eluted at a higher salt concentration than the most anionic plasma isoenzyme. 4. The plasma beta-N-acetylglucosaminidase A isoenzyme of all species contained sialic acid residues whereas only the rabbit, pig and calf liver isoenzymes were sialylated.

Acetylglucosaminidase↗
PubMed1977

Effect of neuraminidase on the chromatographic behaviour of eleven acid hydrolases from human liver and plasma.

1. The elution profiles of eleven acid hydrolases from human liver and plasma were directly compared using a system whereby a single salt gradient was simultaneously applied to two DEAE-cellulose chromatographic columns. 2. Plasma alpha-L-fucosidase, alpha-mannosidase, alpha-galactosidase and alpha-glucosidase isoenzymes were eluted at higher salt concentrations than the corresponding liver isoenzymes whereasbeta-N-acetylglucosaminidase, beta-galactosidase, beta-glucosidase, exo-1,4-beta-xylosidase and alpha-L-arabinofuranosidase isoenzymes were eluted at lower salt concentrations. The elution profiles of beta-glucuronidase and acid phosphatase weremore complex. 3. After incubation with neuraminidase most plasma hydrolases were eluted at lower salt concentrations, however the elution patterns of beta-glucosidase, beta-xylosidase and acid phosphatase were not altered. 4. Preincubation with neuraminidase had no effect on the elution profiles of six liver hydrolases whereas the major isoenzymes of alpha-mannosidase, beta-galactosidase and alpha-L-arabinofuranosidase were eluted at markedly lower salt concentrations. Liver alpha-fucosidase and alpha-galactosidase were eluted at slightly lower salt concentrations afterincubation with neuraminidase. 5. The results are discussed in relation to thepathogenesis of Mucolipidosis II (I-cell disease), and the synthesis and packaging of lysosomal enzymes.

Acetylglucosaminidase↗
PubMed1976

Prenatal diagnosis of Wolman's disease.

Amniocentesis was performed in the 15th week of a pregnancy at risk for Wolman's disease. The cultured amniotic fluid cells were found to have a severe deficiency of acid esterase activity consistent with homozygosity of the fetus. The pregnancy was terminated in the 19th week and the prenatal diagnosis confirmed by enzymic and chemical evaluation of the fetal tissues.

Amniocentesis↗
PubMed1975

I-cell disease (mucolipidosis II): resolution of N-acetyl-beta-D-glucosaminidase and alpha-L-fucosidase components by DEAE-cellulose chromatography.

1. In a patient with I-cell disease the activities of several acid hydrolases were elevated inplasma and reduced in cultured fibroblasts when compared with normal values. Normal activities for the enzymes were found in leucocytes. These findings agree with reports on other cases. 2. N-Acetyl-beta-D-glucosaminidase was resolved into its component forms by chromatography on microcolumns of DEAE-cellulose coupled with continuous automated assay of activity in the column effluent. Cultured skin fibroblasts from three patients showed a profound deficiency of glucosaminidase component A and a relative increase in the activity of a form eluted earlier than A. 3. In the one patient studied, the elution profile of plasma glucosaminidase was similar to that of normal plasma, but treatment with neuraminidase revealed a minor component which did not appear in control specimens. 4. Chromatographic resolution of glucosaminidase secreted by normal fibroblasts into the culture medium shoed that component A comprised two forms, a serum-type and a tissue-type, whereas only a serum-type was found in I-cell medium. 5. Different forma of alpha-L-fucosidase were shown to occur in normal plasma and fibroblasts. This is the second lysosomal hydrolase for which differences between intracellular and extracellular forms have been described and might reflect a general phenomenon. 6. The major acidic component of fucosidase from normal fibroblasts was not detected in I-cell fibroblasts. Elution profiles of fucosidase activity in normal and I-cell plasma were indistinguishable, both before and after treatment with neuraminidase. 7. On the basis of the above findings, we suggest that for several acid hydrolases there is a common biosynthetic reaction, which produces forms of these enzymes destined for incorporation into primary lysosomes rather than secretion by the cell. In cultured fibroblasts from patients with I-cell disease, the enzyme catalysing the reaction leading to the production of intracellular forms is deficient or defective, whereas the synthesis of precursor and secreted forms is unaffected.

Acetylglucosaminidase↗
PubMed1975

Biochemical diagnosis of cystinosis using leukocytes.

A simple method for the biochemical diagnosis of cystinosis involves incubating leukocytes from a small volume of blood with 35S-cystine. Non-protein 35S-labelled compounds are then extracted from the leucocytes and separated by thin-layer chromatography. The excessive incorporation of 35S-cystine into the increased cystine pool of cystine cells is easily detected in autoradiographs of the chromatograms.

Autoradiography↗
PubMed1975

Variability of acid hydrolase activities in cultured skin fibroblasts and amniotic fluid cells.

The specific activities of lysosomal hydrolases in cultured skin fibroblasts and amniotic fluid cells showed wide and unpredictable variations between cultures, which may lead to difficulty in differentiating normal, heterozygous, and homozygous cells. However, the variability for a given culture was similar for all enzymes assayed, so that a clearer differentiation of a relative deficiency of a given enzyme could be obtained by expressing its activity in ratio to that of another enzyme. Activity ratios were particularly useful in the evaluation of enzyme levels in cultured amniotic fluid cells. Results of their application to tests of pregnancies at risk for metachromatic leucodystrophy, Krabbe's leucodystrophy, GM1-gangliosidosis, and GM2-gangliosidosis (Sandhoff variant) are presented.

Amniotic Fluid↗