IgE-based assay for early detection of HIV-1 infection in infants.
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AIDS Serodiagnosis↗
Biomedical subjects
M Fletcher
Publications and source records attributed to M Fletcher.
KCl reabsorption by the lower malpighian tubule of rhodnius prolixus: inhibition by Cl(-) channel blockers and acetazolamide.
Iono- and osmoregulation by the blood-feeding hemipteran Rhodnius prolixus involves co-ordinated actions of the upper and lower Malpighian tubules. The upper tubule secretes ions (Na(+), K(+), Cl(-)) and water, whereas the lower tubule reabsorbs K(+) and Cl(-) but not water. The extent of KCl reabsorption by the lower tubule in vitro was monitored by ion-selective microelectrode measurement of Cl(-) and/or K(+) concentration in droplets of fluid secreted by Malpighian tubules isolated under oil. An earlier study proposed that K(+) reabsorption involves an omeprazole-sensitive apical K(+)/H(+) ATPase and Ba(2+)-sensitive basolateral K(+) channels. This paper examines the effects acetazolamide and of compounds that inhibit chloride channels, Cl(-)/HCO(3)(-) exchangers and Na(+)/K(+)/2Cl(-) or K(+)/Cl(-) co-transporters. The results suggest that Cl(-) reabsorption is inhibited by acetazolamide and by Cl(-) channel blockers, including diphenylamine-2-carboxylate(DPC) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), but not by compounds that block Na(+)/K(+)/Cl(-) and K(+)/Cl(-) co-transporters. Measurements of transepithelial potential and basolateral membrane potential during changes in bathing saline chloride concentration indicate the presence of DPC- and NPPB-sensitive chloride channels in the basolateral membrane. A working hypothesis of ion movements during KCl reabsorption proposes that Cl(-) moves from lumen to cell through a stilbene-insensitive Cl(-)/HCO(3)(-) exchanger and then exits the cell through basolateral Cl(-) channels.
Journal Article↗
Calcifying odontogenic cyst: a clinicopathologic study of 57 cases with immunohistochemical evaluation for cytokeratin.
PURPOSE: A clinicopathologic study of all cases accessioned as calcifying odontogenic cyst (COC) from 1971 to 1996 from the files of the Oral Pathology Laboratory at Temple University School of Medicine was undertaken. MATERIALS AND METHODS: Microscopic slides and clinical histories of cases diagnosed as calcifying odontogenic cyst were reviewed and analyzed. Ten cases were processed for cytokeratin immunohistochemical staining. RESULTS: Fifty-seven cases were reviewed, 28 males and 29 females. Patients' ages ranged from 7 to 83 years, with a mean age of 49.8 years. Thirty-four cases involved the mandible and 23 were from the maxilla. Seventeen were reported in peripheral locations, and 38 occurred centrally within the jaws. Two were found both centrally and peripherally. The most common clinical sign for central lesions was a radiolucency sometimes associated with a jaw expansion. The most common clinical complaint for peripheral lesions was a nodular growth on the gingiva. Although lining epithelial cells were strongly positive for cytokeratin, full-brown ghost cells and disintegrating ghost cells were nonreactive. CONCLUSION: Calcifying odontogenic cyst can occur in any age-group, intraosseously or extraosseously, and as a solid lesion. No recurrences were found after surgical removal in the current series.
Adolescent↗
Respiratory function parameters in infants using inductive plethysmography.
A signal processing technique has been developed to determine respiratory function parameters by processing displacement data obtained from the abdomen and the rib cage of infants using respiratory inductive plethysmography. The technique transforms time-variant signals into the frequency domain, where they are filtered to reduce unwanted signal components. The phase relationship between the abdominal displacement and the rib cage displacement is determined from the phases of the filtered signals. Flow-volume loops, which are currently of great interest in respiratory medicine, are obtained from waveforms representing respiratory tidal flow and respiratory tidal volume. The index of respiratory timing is determined from a waveform representing respiratory tidal flow. The technique has been verified by statistical comparison with data simultaneously obtained using pneumotachography in a clinical study involving 49 infants.
Artifacts↗
Regulation of human T-lymphocyte proliferative responses by the lipoxygenase product 15-HETE.
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Cells, Cultured↗
Identification of pesticide poisoning in wildlife.
The Wildlife Incident Investigation Scheme investigates incidents of suspected poisoning of wildlife (also honey bees and companion animals) by pesticides in the United Kingdom. The approach to these investigations has evolved over the past 30 years. Field investigations, post-mortem examinations, toxicological data and experience of previous poisoning incidents assist in the selection and interpretation of appropriate chemical analyses. Several 'multi-residue' and several 'individual compound' analytical methods for pesticides in wildlife are currently in use; these are described.
Animals↗
[Pediatric vaccines tomorrow].
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Forecasting↗
Pseudomonas fluorescens adhesion and transport through porous media are affected by lipopolysaccharide composition.
The objectives of this work were (i) to use transposon mutagenesis to produce mutants of Pseudomonas fluorescens that were altered in adhesion ability and transport through porous media and (ii) to identify the alterations in surface characteristics that were responsible for the changes in attachment. Mutants of P. fluorescens were generated with TnphoA, which enabled identification of mutants that were altered in surface proteins. Transposon mutants were screened for alterations in adhesion ability by attachment assays on hydrophobic polystyrene and water-wettable polystyrene. Four TnphoA mutants with increased adhesion to the hydrophobic surface and decreased adhesion to the water-wettable surface were obtained. Transport of the strains through porous media was evaluated by passing suspensions of each mutant and the parent through columns containing quartz sand and determining the number of cells retained in the columns. The mutants all demonstrated increased adhesion and retention in the columns. Southern analysis demonstrated two types of mutants with separate transposon insertion sites. Polyacrylamide gel electrophoresis of the strains demonstrated that the O antigen on the lipopolysaccharide was either attenuated or absent. Lack of this polysaccharide, and the consequent increased exposure of the lipid moiety of the lipopolysaccharide, is probably responsible for the increase in adhesion to the hydrophobic substrata and retention in the sand column. This work combined with previous studies of attachment of P. fluorescens demonstrates that more than one type of polymer can mediate the adhesion of this organism to nonbiological surfaces.
Bacterial Adhesion↗
Elevated IgE level in relationship to nutritional status and immune parameters in early human immunodeficiency virus-1 disease.
Elevation of IgE has been associated with T-cell dysregulation and with the occurrence of opportunistic infections in patients with acquired immunodeficiency syndrome. The precise cause of IgE overproduction during the early stages of human immunodeficiency virus (HIV)-1 disease, however, has not been established. In light of reports demonstrating that IgE production may be affected by vitamin E levels in an animal model, we evaluated nutritional status in relationship to plasma IgE levels and immune parameters in 100 asymptomatic HIV-1-seropositive and 42 HIV-1-seronegative homosexual men. Approximately 18% of the HIV-1-seropositive population demonstrated biochemical evidence of plasma vitamin E deficiency (< 5 micrograms/ml). Subsequent analysis of available samples indicated a dramatic elevation of IgE levels (308 +/- 112 IU/ml) in vitamin E-deficient seropositive subjects (n = 9) as compared with age and CD4-matched HIV-1-seropositive persons with adequate vitamin E levels (n = 16, 118.1 +/- 41.1 IU/ml) and significantly lower levels (59.5 +/- 15.7 IU/ml) in HIV-1-seronegative men (n = 20, p = 0.01). This effect, which was independent of CD4 cell count, did not appear to be influenced by atopic or gastrointestinal parasitic disease. The low plasma vitamin E levels were related at least in part to dietary intake (r = 0.552, p = 0.01), suggesting that supplementation may be warranted in HIV-1-infected persons in whom vitamin E deficiency develops. Analysis of covariance revealed a strong relationship between IgE levels and CD8 cell counts (p < 0.006), and between IgE level and vitamin E deficiency (p < 0.039).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Bacterial adhesion to hydroxyl- and methyl-terminated alkanethiol self-assembled monolayers.
The attachment of bacteria to solid surfaces is influenced by substratum chemistry, but to determine the mechanistic basis of this relationship, homogeneous, well-defined substrata are required. Self-assembled monolayers (SAMs) were constructed from alkanethiols to produce a range of substrata with different exposed functional groups, i.e., methyl and hydroxyl groups and a series of mixtures of the two. Percentages of hydroxyl groups in the SAMs and substratum wettability were measured by X-ray photoelectron spectroscopy and contact angles of water and hexadecane, respectively. SAMs exhibited various substratum compositions and wettabilities, ranging from hydrophilic, hydroxyl-terminated monolayers to hydrophobic, methyl-terminated monolayers. The kinetics of attachment of an estuarine bacterium to these surfaces in a laminar flow chamber were measured over periods of 120 min. The initial rate of net adhesion, the number of cells attached after 120 min, the percentage of attached cells that adsorbed or desorbed between successive measurements, and the residence times of attached cells were quantified by phase-contrast microscopy and digital image processing. The greatest numbers of attached cells occurred on hydrophobic surfaces, because (i) the initial rates of adhesion and the mean numbers of cells that attached after 120 min increased with the methyl content of the SAM and the contact angle of water and (ii) the percentage of cells that desorbed between successive measurements (ca. 2 min) decreased with increasing substratum hydrophobicity. With all surfaces, 60 to 80% of the cells that desorbed during the 120-min exposure period had residence times of less than 10 min, suggesting that establishment of firm adhesion occurred quickly on all of the test surfaces.
Adsorption↗
Bacterial biofilms and biofouling.
Advances in the development and application of investigative tools, such as scanning confocal laser microscopy and genetic techniques, are leading to new insights concerning the composition, structure, and function of bacterial biofilms. Molecular biology has also demonstrated that bacteria are able to 'sense' surface environments, altering their pattern of gene expression. Recent studies on mechanisms of bacterial attachment provide further evidence for the diversity of attachment mechanisms, as do investigations of attachment interactions between bacteria and invertebrates.
Animals↗
Colonization of urinary catheters by Escherichia coli and Providencia stuartii in a laboratory model system.
A laboratory model system was developed to investigate the progressive colonization of urinary catheters by Escherichia coli Providencia stuartii, prominent organisms in the polymicrobial bacteriuria of the long-term catheterized urinary tract. We hypothesized that colonization of the catheter and artificial urine by E. coli is influenced by the presence of P. stuartii. E. coli or P. stuartii in pure culture both rapidly colonized the artificial urine and catheters, and both persisted throughout all experiments. In systems containing both organisms, P. stuartii occurred in significantly higher numbers in the artificial urine and on the catheters than E. coli (p < 0.05). To obtain similar numbers of E. coli and P. stuartii in the artificial urine, citrate was eliminated; however, P. stuartii still dominated on the catheter surfaces. The presence of P. stuartii appeared to facilitate growth of E. coli in the artificial urine, yet reduce numbers of E. coli on the catheter. In a separate experiment using different strains of E. coli and P. stuartii, the latter was dominant in the artificial urine and on the catheter surfaces. However, this strain of P. stuartii (which was urease positive) did not facilitate growth of E. coli. The interaction between these strains may have been considerably affected by urea hydrolysis, which resulted in an increase in pH (6.5 to > 8.5) and considerable precipitate formation in the model system. The paradox of P. stuartii enhancing colonization by E. coli in the artificial urine, yet inhibiting its colonization on the catheter surface, illustrates the complexity of polymicrobial interactions in colonization of the catheterized urinary tract.
Bacteriuria↗
Onchocerciasis in field workers at Baya Farm, Teppi Coffee Plantation Project, southwestern Ethiopia: prevalence and impact on productivity.
A survey of onchocerciasis in male field workers was conducted in Baya Farm, Teppi Coffee Plantation Project, southwestern Ethiopia, in order to determine the prevalence rate of onchocerciasis in that population and to measure the effect of the disease on work productivity. A total of 196 study subjects were examined both clinically and parasitologically. Parasitological diagnosis was based on bilateral skin biopsies from the calf, buttock, and scapula. It was found that the prevalence rate of onchocerciasis (82.7%) and the intensity of infection were very high. No study subject had any detectable visual impairment, and other chronic manifestations were few. Based on a twelve month retrospective review of labour cards, workers with onchocerciasis were significantly more likely to be absent from work due to illness and other reasons, and earned significantly less wages, than workers without onchocerciasis, thus suggesting that non-blinding onchocerciasis has a negative impact on work productivity.
Adult↗
Effect of tricyclic antidepressants on switching to mania and on the onset of bipolarity in depressed 6- to 12-year-olds.
The authors present data on the rates of onset of bipolar phenomena, at 2- to 3-year follow-up, in depressed 6- to 12-year olds. The subjects had participated in the nortriptyline drug study. There were high rates of onset of bipolarity and of switching to mania while patients were on tricyclic antidepressants (TCAs). Mania developed only in subjects who had received TCAs at some time in the past or were receiving them concurrent with the onset of mania. These findings were analyzed with respect to the influence of multiple covariates, including family history of manic disorders and pubertal status. The authors discuss the implications of these findings for the prescription of TCAs to children who present with major depressive disorder and have a family history of bipolarity or a history of bipolar symptoms. The relevance of these findings for the later development of rapid cycling is discussed and compared with predictors of rapid cycling in adults.
Antidepressive Agents, Tricyclic↗
Using fish against malaria: a local initiative.
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Animals↗
Prospects for the use of larvivorous fish for malaria control in Ethiopia: search for indigenous species and evaluation of their feeding capacity for mosquito larvae.
Because of problems with drug and insecticide resistance, the National Organization for the Control of Malaria and other Vectorborne Diseases, Ethiopia, has embarked on a programme of research on alternative malaria control methods, including the use of biological control agents, such as larvivorous fish. The objectives of the study were to identify indigenous larvivorous fish species which could be potential candidates for use as biological control agents; to extend knowledge of their distribution in Ethiopia; and to conduct laboratory tests to determine their feeding capacity. An extensive search resulted in the identification of 11 larvivorous fish species indigenous to Ethiopia, including five species previously unrecorded in the country. Seven species were assessed under standard laboratory conditions for their feeding capacity on larvae of Anopheles gambiae s.l. and Culex andersoni. All species tested were efficient larvivores in the laboratory. However, their larvivorous capacity should be tested further in field trials. Based on the findings of this study, two priority areas for the assessment of biological control using larvivorous fish were identified, the port city of Assab, using the local species Aphanius dispar, and the Ogaden, south-eastern Ethiopia, using the local species Oreochromis spilurus spilurus.
Animals↗
Clinical trials: comparing dressings.
This article describes results from one of the sites involved in a multi-centred comparative study designed to assess the performance of a collagen-alginate dressing used in the treatment of leg ulceration. The research methods used in the trial, as well as the results, will be of interest to practising nurses. Those involved in similar work are invited to submit articles to be considered for publication in future issues of this supplement.
Alginates↗
A pilot study of dried blood spot testing for HIV antibody in neonates.
An unlinked anonymous HIV antibody study of neonates, using surplus dried blood spots on Guthrie cards, was introduced as a means of estimating the prevalence of HIV infection in childbearing women. From March 1990 to February 1992, blood spots from 14,520 infants were tested for anti-HIV, using an HIV IgG antibody capture particle-adherence test; only one sample gave a confirmed positive reaction. This type of study involves no interference in routine care and can be operated without difficulty in a district general hospital setting where neonatal metabolic screening is performed.
AIDS Serodiagnosis↗