Biomedical subjects

J Wilson

Publications and source records attributed to J Wilson.

At least 73 records · Page 4Linked to original sources

PubMed2002

Can motivational signs prompt increases in incidental physical activity in an Australian health-care facility?

This study aimed to evaluate whether a stair-promoting signed intervention could increase the use of the stairs over the elevator in a health-care facility. A time-series design was conducted over 12 weeks. Data were collected before, during and after displaying a signed intervention during weeks 4-5 and 8-9. Evaluation included anonymous counts recorded by an objective unobtrusive motion-sensing device of people entering the elevator or the stairs. Self-report data on stair use by hospital staff were also collected. Stair use significantly increased after the first intervention phase (P = 0.02), but after the intervention was removed stair use decreased back towards baseline levels. Moreover, stair use did not significantly change after the re-introduction of the intervention. Lastly, stair use decreased below the initial baseline level during the final weeks of evaluation. Furthermore, there was no significant change in self-reported stair use by hospital staff. Therefore, the signed intervention aimed at promoting an increase in incidental physical activity produced small brief effects, which were not maintained. Further research is required to find more effective 'point of choice' interventions to increase incidental physical activity participation with more sustainable impact.

Adult↗

PubMed2002

Pancreatic stellate cells respond to inflammatory cytokines: potential role in chronic pancreatitis.

BACKGROUND: It is now generally accepted that chronic pancreatic injury and fibrosis may result from repeated episodes of acute pancreatic necroinflammation (the necrosis-fibrosis sequence). Recent studies suggest that pancreatic stellate cells (PSCs), when activated, may play an important role in the development of pancreatic fibrosis. Factors that may influence PSC activation during pancreatic necroinflammation include cytokines known to be important in the pathogenesis of acute pancreatitis, such as tumour necrosis factor alpha (TNF-alpha), and the interleukins 1, 6, and 10 (IL-1, IL-6, and IL-10). AIM: To determine the effects of these cytokines on PSC activation, as assessed by cell proliferation, alpha smooth muscle actin (alpha-SMA) expression, and collagen synthesis. METHODS: Cultured rat PSCs were incubated with cytokines for 24 hours. Cell proliferation was assessed by measuring (3)H thymidine incorporation into cellular DNA, alpha-SMA expression by western blotting, and collagen synthesis by incorporation of (14)C proline into collagenase sensitive protein. mRNA levels for procollagen alpha(1)(1) in PSCs were determined by northern and dot blotting methods. RESULTS: Expression of alpha-SMA by PSCs was increased on exposure to each of the cytokines used in the study. Stellate cell proliferation was stimulated by TNF-alpha but inhibited by IL-6, while IL-1 and IL-10 had no effect on PSC proliferation. Collagen synthesis by PSCs was stimulated by TNF-alpha and IL-10, inhibited in response to IL-6, and unaltered by IL-1. Changes in collagen protein synthesis in response to TNF-alpha, IL-10, and IL-6 were not regulated at the mRNA level in the cells. CONCLUSION: This study has demonstrated that PSCs have the capacity to respond to cytokines known to be upregulated during acute pancreatitis. Persistent activation of PSCs by cytokines during acute pancreatitis may be a factor involved in the progression from acute pancreatitis to chronic pancreatic injury and fibrosis.

Actins↗

PubMed2002

Magnetic resonance brain imaging in people with dizziness: a comparison with non-dizzy people.

BACKGROUND: Dizziness is a common symptom affecting about 30% of people over the age of 65. OBJECTIVE: To investigate the hypothesis that structural abnormalities of the brain and cervical cord are more common in dizzy than in non-dizzy subjects. METHODS: A case-control study of subjects over the age of 65 with and without dizziness: 125 dizzy subjects and 86 non-dizzy subjects were recruited from the community through articles in the local press. Magnetic resonance imaging (MRI) of the brain and neck was performed, and was read by a consultant neuroradiologist blind to the clinical details. RESULTS: All dizzy subjects and all controls had at least one structural abnormality. Cerebral atrophy was found in 86% of dizzy subjects and 85% controls (p = 1.0) At least one white matter lesion was found in 69% of dizzy subjects and 78% controls (p = 0.21). White matter lesions in the midbrain were more common in dizzy than in non-dizzy subjects (22% v 4%, p < 0.001). There were no significant differences in the prevalence of cord compression, cervical subluxation, facet joint degeneration, vertebral artery compression, or vertebral artery occlusion between dizzy and non-dizzy subjects. CONCLUSIONS: Structural abnormalities of the brain and neck are common in both dizzy and non-dizzy subjects. "Routine" MRI is unlikely to reveal a specific cause for dizziness. The observation of more frequent white matter lesions in the midbrain in dizzy subjects requires further study to determine whether small vessel changes could cause dizziness in older people.

Aged↗

PubMed2001

Allograft rejection predicts the occurrence of late-onset cytomegalovirus (CMV) disease among CMV-mismatched solid organ transplant patients receiving prophylaxis with oral ganciclovir.

The natural history of cytomegalovirus (CMV) disease associated with solid organ transplantation has been modified as a result of the widespread use of antiviral prophylaxis. Anecdotal reports have indicated a reduction of CMV disease at the expense of its later occurrence after completion of ganciclovir prophylaxis. The present study investigated the occurrence of CMV disease and its risk factors among 37 liver and kidney transplant recipients with CMV D+/R- status who received oral ganciclovir during the first 100 days posttransplantation. CMV disease occurred in 9 patients (24.3%) at a median of 144 days posttransplantation (range, 95-190 days). Allograft rejection was found to be strongly associated with the occurrence of late-onset CMV disease (risk ratio, 6.6; 95% confidence interval, 1.4-32.1; P=.02). Thus, CMV D+/R- solid organ transplant recipients receiving 3 months of oral ganciclovir who develop allograft rejection during the period of antiviral prophylaxis may benefit from extended and/or enhanced antiviral prophylaxis to prevent late-onset CMV disease.

Administration, Oral↗

PubMed2001

The discovery of sulfonylated dipeptides as potent VLA-4 antagonists.

Directed screening of a carboxylic acid-containing combinatorial library led to the discovery of potent inhibitors of the integrin VLA-4. Subsequent optimization by solid-phase synthesis afforded a series of sulfonylated dipeptide inhibitors with structural components that when combined in a single hybrid molecule gave a sub-nanomolar inhibitor as a lead for medicinal chemistry. Preliminary metabolic studies led to the discovery of substituted biphenyl derivatives with low picomolar activities. SAR and pharmacokinetic characterization of this series are presented.

Animals↗

PubMed2001

Improvement of forage production in Calliandra calothyrsus: methodology for the identification of an effective inoculum containing Rhizobium strains and arbuscular mycorrhizal isolates.

The overall aim of this paper is to describe the selection of effective rhizobia and arbuscular mycorrhizas (AM), which after inoculation, will significantly improve the forage production of Calliandra calothyrsus under field conditions. To achieve this objective, the following activities were carried out: (i) establishment from both nodules and soil samples of a collection of microsymbionts (rhizobium and AM) of C. calothyrsus from Central America (Mexico, Honduras, Guatemala, Nicaragua and Costa Rica), also from outside its native range in Cameroon, Kenya and New Caledonia; (ii) identification under glasshouse conditions of the most effective rhizobia and AM isolates; (iii) production of a solid selected inoculum for field trials; (iv) examination of the impact of the inoculation on the growth of C. calothyrsus monitored under nursery conditions. We have screened 446 rhizobia strains in the nursery and identified six as being very effective at nodulating the host plant. They originated from Costa Rica (CCCR15 and CCCR1), from New Caledonia (CCNC26), from Cameroon (CCC22) and from Kenya (KWN35 and KCC6). In relation to AM, five isolates have been selected for the ability to infect and promote growth of the host plant--two isolates of Gigaspora albida isolated from Kenya (GA1b and GA2); one isolate of Scutellospora verrucosa isolated from Kenya (SV2c); one isolate of Scutellospora calospora isolated from Guatemala (SC2) and one isolate of Glomus etunicatum isolated from Honduras (GE1). Further experiments will test these selected inocula, singly and in mixtures, in order to obtain an inoculant which significantly improves the growth of C. calothyrsus and to enable its distribution to farmers who use this woody legume for forage production on their farms.

Kenya↗

PubMed2001

Analysis of CC chemokine and chemokine receptor expression in solid ovarian tumours.

To understand the chemokine network in a tissue, both chemokine and chemokine receptor expression should be studied. Human epithelial ovarian tumours express a range of chemokines but little is known about the expression and localisation of chemokine receptors. With the aim of understanding chemokine action in this cancer, we investigated receptors for CC-chemokines and their ligands in 25 biopsies of human ovarian cancer. CC-chemokine receptor mRNA was generally absent from solid tumours, the exception being CCR1 which was detected in samples from 75% of patients. CCR1 mRNA localised to macrophages and lymphocytes and there was a correlation between numbers of CD8(+) and CCR1 expressing cells (P = 0.031). mRNA for 6 CC-chemokines was expressed in a majority of tumour samples. In a monocytic cell line in vitro, we found that CCR1 mRNA expression was increased 5-fold by hypoxia. We suggest that the CC-chemokine network in ovarian cancer is controlled at the level of CC-chemokine receptors and this may account for the phenotypes of infiltrating cells found in these tumours. The leukocyte infiltrate may contribute to tumour growth and spread by providing growth survival factors and matrix metalloproteases. Thus, CCR1 may be a novel therapeutic target in ovarian cancer.

Adenocarcinoma, Clear Cell↗

PubMed2001

Mechanisms associated with tumor vascular shut-down induced by combretastatin A-4 phosphate: intravital microscopy and measurement of vascular permeability.

The tumor vascular effects of the tubulin destabilizing agent disodium combretastatinA-4 3-O-phosphate (CA-4-P) were investigated in the rat P22 tumor growing in a dorsal skin flap window chamber implanted into BD9 rats. CA-4-P is in clinical trial as a tumor vascular targeting agent. In animal tumors, it can cause the shut-down of blood flow, leading to extensive tumor cell necrosis. However, the mechanisms leading to vascular shut-down are still unknown. Tumor vascular effects were visualized and monitored on-line before and after the administration of two doses of CA-4-P (30 and 100 mg/kg) using intravital microscopy. The combined effect of CA-4-P and systemic nitric oxide synthase (NOS) inhibition using N(omega)-nitro-L-arginine (L-NNA) was also assessed, because this combination has been shown previously to have a potentiating effect. The early effect of CA-4-P on tumor vascular permeability to albumin was determined to assess whether this could be involved in the mechanism of action of the drug. Tumor blood flow reduction was extremely rapid after CA-4-P treatment, with red cell velocity decreasing throughout the observation period and dropping to <5% of the starting value by 1 h. NOS inhibition alone caused a 50% decrease in red cell velocity, and the combined treatment of CA-4-P and NOS inhibition was approximately additive. The mechanism of blood flow reduction was very different for NOS inhibition and CA-4-P. That of NOS inhibition could be explained by a decrease in vessel diameter, which was most profound on the arteriolar side of the tumor circulation. In contrast, the effects of CA-4-P resembled an acute inflammatory reaction resulting in a visible loss of a large proportion of the smallest blood vessels. There was some return of visible vasculature at 1 h after treatment, but the blood in these vessels was static or nearly so, and many of the vessels were distended. The hematocrit within larger draining tumor venules tended to increase at early times after CA-4-P, suggesting fluid loss from the blood. The stacking of red cells to form rouleaux was also a common feature, coincident with slowing of blood flow; and these two factors would lead to an increase in viscous resistance to blood flow. Tumor vascular permeability to albumin was increased to approximately 160% of control values at 1 and 10 min after treatment. This could lead to an early decrease in tumor blood flow via an imbalance between intravascular and tissue pressures and/or an increase in blood viscosity as a result of increased hematocrit. These results suggest a mechanism of action of CA-4-P in vivo. Combination of CA-4-P with a NOS inhibitor has an additive effect, which it may be possible to exploit therapeutically.

Angiogenesis Inhibitors↗

PubMed2001

Simultaneous measurement of six cytokines in a single sample of human tears using microparticle-based flow cytometry: allergics vs. non-allergics.

Tears play an essential role in maintaining corneal and conjunctival integrity by providing a tightly regulated, optimal extracellular environment critical to its numerous functions, which include anti-microbial defense, wound healing and inflammatory responses such as allergies. Elevated levels of inflammatory cytokines have been reported in tears from various ocular disease states. Characterization of tear cytokines has been limited by the small volume (microliter amounts) attainable. This limitation was addressed with the newly developed Becton Dickinson Cytometric Bead Array (CBA), which combines the principles of the "sandwich" immunoassay with the capability of flow cytometry for simultaneous measurement of the characteristics of multiple particles. This technique allows determination of six human cytokine (IFNgamma, TNFalpha, IL-2, IL-4, IL-5, IL-10) concentrations simultaneously in a single tear sample. Tears were collected from the inferior fornix of non-allergic (n=7) and allergic (n=9) donors. Each tear sample or cytokine standard was incubated with a mixture of capture Ab-bead reagent and detector Ab-phycoerythrin (PE) reagent, and analyzed using flow cytometry. All six cytokines were detectable in both non-allergic and allergic tears. Tears from allergic donors contained significantly less IL-10 (p=0.035), and had significant increases in the ratios of TNFalpha/IFNgamma, IL-5/IFNgamma and IL-5/IL-10 (p=0.0008, 0.0124 and 0.011, respectively). The small volume required (5-10 microl/test) by the Cytometric Bead Array allows measurement of all six cytokines from a single collection of tears. This decreases collection time, minimizing the confounding effect of stimulation on cytokine concentration in tears, as well as allowing calculation of cytokine ratios.

Adult↗

PubMed2001

Mutations in the measles virus C protein that up regulate viral RNA synthesis.

The measles virus RNA-dependent RNA polymerase consists of two virus-encoded subunits, the phosphoprotein (P) and the large (L) protein. The P mRNA also codes for a C protein in the +1 reading frame relative to P. The activities of the measles P and C proteins from the vaccine strain, EdB, a wild-type CM strain, and an SSPE P4 strain were investigated using a CAT reporter minigenome assay. CAT is synthesized following replication and transcription of a DI-CAT minigenome supported by individual P, L, and N plasmids expressed in a mammalian expression system. As measured by CAT activity, CMP1 and P4P1 stimulate transcription and replication four- to six- and six- to eightfold, respectively, better than EdP. There are 10 and 16 amino acid changes in the P protein and three and four changes in C in CMP1 and P4P1, respectively, relative to EdP. By constructing chimeric P genes we showed that mutations throughout P4P1 were required for enhanced polymerase activity, while only mutations in the 5'-terminal portion, encompassing the C ORF, of the CMP1 gene mediated stimulation. Abrogation of C expression from the Ed and CM P genes resulted in an increase in RNA synthesis of twofold for CMP1S and four- to fivefold for EdPS. With the addition of C protein expressed from a separate plasmid that contains only the C ORF, EdC reduces viral RNA synthesis more strongly than CMC. These data suggest that EdC and CMC proteins give a differential inhibition that accounts for most of the differences in RNA synthesis by EdP and CMP1.

Carrier Proteins↗

PubMed2001

Mutagenicity of bay-region amino-substituted cyclopenta[a]phenanthrenes and 2- and 5-aminochrysene.

The relative mutagenic potentials of 11-amino-16,17-dihydro-15H-cyclopenta[a]phenanthrene, its 17-keto derivative, and 2- and 5-aminochrysene have been compared in Salmonella typhimurium TA98 and TA100 in the presence of a postmitochondrial liver preparation from Aroclor 1254 induced rats. The 11-amino hydrocarbon is a very weak mutagen (0.27 revertants/nmol), whereas the 11-amino-17-ketone is much more active (129 revertants/nmol). 2-Aminochrysene is the most mutagenic arylamine ( approximately 500 revertants/nmol) among these compounds, but its 5-amino isomer is much less active (0.9 revertants/nmol). Possible reasons for these marked differences are suggested. Use of TA98 with over-expressing O-acetyltransferase (YG 1024) and deficient in this enzyme (TA98/l,8-DNP(6)) with the 11-amino-17-ketone and with 5-aminochrysene clearly indicates the importance of this enzyme in their bioactivation, implying oxidation of the amino group to the hydroxylamine in both these compounds.

Androstenes↗

PubMed2001

Pineal transplantation after pinealectomy in young chickens has no effect on the development of scoliosis.

STUDY DESIGN: Three experimental groups and one control group of chickens underwent different surgical procedures to determine the effects of pineal gland transplantation on the development of scoliosis. OBJECTIVE: To determine whether transplantation of the pineal gland to the body wall musculature maintains serum melatonin levels at normal values and prevents the development of scoliosis. SUMMARY OF BACKGROUND DATA: Scoliosis occurs consistently after pinealectomy in young chickens. Many characteristics of this scoliosis are similar to those seen in patients with adolescent idiopathic scoliosis. It is not clear whether the underlying mechanism is dependent on reduced levels of serum melatonin or some other aspect of the extensive surgery. METHODS: Four groups of chickens were selected: normal chickens, pinealectomized chickens, chickens that underwent simple cutting of the pineal stalk, and chickens that underwent transplantation of the pineal gland into the body wall. Development of scoliosis was determined from measurement of the Cobb angle from weekly radiographs. RESULTS: All of the experimental groups showed the same levels of incidence and the same patterns of scoliosis development. Serum melatonin levels were reduced to nearly zero in all the experimental groups for the duration of the experiment. Scoliosis developed in none of the normal chickens. CONCLUSIONS: Neither transplantation of the pineal gland into the body wall musculature nor simple cutting of the pineal stalk was able to maintain normal levels of serum melatonin because both procedures reduced levels to nearly zero. The incidence and pattern of scoliosis development in these groups were the same as those for the pinealectomized group. Reduction of serum melatonin levels remains a prerequisite for scoliosis development in young chickens.

Animals↗

PubMed2001

Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses.

The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.

Arginine↗

PubMed2001

The critical stage of pinealectomy surgery after which scoliosis is produced in young chickens.

STUDY DESIGN: Stages of the surgical procedure for pinealectomy in chickens were identified. Groups of chickens were selected for each stage. Scoliosis development was identified from radiographs. OBJECTIVES: To determine the critical stage of surgery for pinealectomy after which scoliosis develops in young chickens. SUMMARY OF BACKGROUND DATA: Pinealectomy in young chickens consistently produces scoliosis in young chickens that has many characteristics similar to those seen in patients with adolescent idiopathic scoliosis. The mechanism behind this phenomenon remains unknown. METHODS: Five distinct stages in the pinealectomy surgery were identified. Groups of chickens were selected to undergo surgery to represent these five stages. Scoliosis was determined from weekly radiographs. RESULTS: Cutting the pineal stalk was identified as the critical stage in the surgery after which scoliosis developed. The incidence of scoliosis did not increase after more extensive surgery in which the pineal bulb was removed from the skull. This stage was also correlated with a significant reduction of serum melatonin levels. CONCLUSIONS: Cutting the pineal stalk was identified as the critical stage of pinealectomy surgery after which scoliosis may develop. This stage was also correlated with the significant reduction of average serum melatonin levels. These results allow the focus of attention into the mechanism behind this phenomenon to center on the consequences of cutting the pineal stalk rather than total removal of the pineal gland.

Animals↗

PubMed2001

Hatchery-level predictive values for infectious pancreatic necrosis virus and Aeromonas salmonicida in Ontario, Canada.

The probability and uncertainty of correctly classifying the IPNV and Aeromonas salmonicida status of fish-rearing and natural sites in Ontario were estimated through Monte Carlo simulations. Propagating several uncertain inputs showed the extent to which natural variability and our present lack of knowledge affect the probability of site misclassification. For the scenarios investigated, the site-level negative predictive values (SNPVs) were high and fairly constant. The site-level positive predictive values (SPPVs) - given a test specificity ranging between 0.999 and 1.0 - were much lower, more variable, and highly affected by cut-off point and sample size. Substantial uncertainty resides in classifying the pathogen status of test-positive sites, whereas much less uncertainty resides in classifying pathogen status of test-negative sites.

Aeromonas↗

PubMed2001

Evaluation of the HUD lead hazard control grant program: early overall findings.

This study evaluates the effectiveness of lead hazard control methods used in the Lead Hazard Control (LHC) grant program of U.S. Department of Housing and Urban Development. The LHC Program awards funds to local jurisdictions to address lead hazards in privately owned, low-income dwellings. Grantees in 14 cities, states, or counties collected environmental data in over 2600-treated dwellings making this the largest study of residential lead hazard control ever undertaken. Grantees employed a range of treatments, the most common being replacement of windows and repair of deteriorated lead-based paint. In this paper, dust lead loading levels and blood lead levels of children (6 months-6 years, if present) were observed at four periods of time (preintervention, immediate, and 6- and 12-months postintervention) in 1212 dwellings. Dust lead loading levels were also observed in a subset of these dwellings at 24- and 36-months postintervention. The geometric mean floor and window dust lead loadings declined at least 50 and 88% (P<0.0001), respectively, immediately postintervention. Three years later, floor dust lead loadings remained at or below the immediate postintervention levels. Window dust lead loadings had moderate increases, but remained substantially reduced from preintervention levels and below clearance standards. At 1 year after intervention, geometric mean age-adjusted blood lead levels had declined from 11.0 to 8.2 microg/dL, a 26% decline (P<0.0001). The LHC Program interventions produced blood lead declines similar to or greater than the percentage changes reported in earlier 1-year lead intervention studies.

Child↗

PubMed2001

Facilitation of enkephalins catabolism inhibitor-induced antinociception by drugs classically used in pain management.

The aim of this study was to investigate the facilitatory effects of subanalgesic or low doses of different drugs (acetylsalicylic acid, ibuprofen and morphine) on the antinociceptive responses induced by the endogenous opioid peptides, enkephalins, protected from their catabolism by the dual enkephalin-degrading enzymes inhibitor RB101. According to the analgesic profile of the three studied compounds different antinociceptive assays were used: the hot plate and formalin tests in mice, and the tail flick and paw pressure tests on inflamed paws in rats and polyarthritic rats. Facilitatory effects of subanalgesic doses of acetylsalicylic acid and ibuprofen on RB101-induced antinociceptive responses were observed in the early and late phases of the formalin test, respectively. In the hot plate, tail flick and paw pressure tests, the dose-dependent analgesic effects of RB101 were strongly potentiated by subanalgesic doses of morphine (0.5 mg/kg), while in these tests, acetylsalicylic acid and ibuprofen were unable to modify the RB101-induced antinociceptive responses. The synergism in antinociceptive effects observed with the combination of RB101 and morphine supported by isobolographic analysis, may have interesting clinical implications, considering both the lack of opiate drawbacks observed with RB101 and the high potentiation of its antinociceptive effects with very low doses of morphine.

Analgesics↗

PubMed2001

Characterization of the ornithine aminotransferase from Plasmodium falciparum.

The ornithine aminotransferase from Plasmodium falciparum 3D7 was cloned, functionally expressed, and characterized. The gene exists as a single copy in the malarial genome and is located on chromosomes 6/7/8. The deduced amino acid sequence was found to be 85% identical to a similar sequence discovered in Plasmodium yoelii, 82% identical to a partial sequence from Plasmodium vivax, and 42-53% identical to ornithine aminotransferases from other eukaryotes. The enzyme had a very narrow substrate specificity, and could only catalyze the transamination of alpha-ketoglutarate with ornithine or N-acetylornithine, and of glutamate-5-semialdehyde with glutamate and alanine. The aminooxy analogue of ornithine, canaline, was found to inhibit the ornithine aminotransferase uncompetatively with a Ki of 492+/-98 nM. As the enzyme effectively catalyzed both ornithine catabolism and formation, its potential role in ornithine biosynthesis from glutamine, via glutamate, glutamate-5-phosphate, and glutamate-5-semialdehyde, was examined. Over the course of a 3.5 h incubation, P. falciparum converted 34% of exogenous, radiolabeled glutamine to glutamate and 0.68% to ornithine. This low level of conversion suggests that the parasite may have alternative mechanisms for obtaining ornithine for polyamine biosynthesis.

Amino Acid Sequence↗