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Biomedical subjects

A Cunningham

Publications and source records attributed to A Cunningham.

At least 55 records · Page 3Linked to original sources
PubMed1996

The relationship between upper respiratory infections and hospital admissions for asthma: a time-trend analysis.

We have shown that viruses are associated with 80 to 85% of asthma exacerbations in school-age children in the community. We hypothesize that viral infections are also associated with severe attacks of asthma precipitating hospital admissions. To investigate this, we conducted a time-trend analysis, comparing the seasonal patterns of respiratory infections and hospital admissions for asthma in adults and children. During a 1-yr study in the Southampton area of the United Kingdom, 108 school-age children monitored upper and lower respiratory symptoms and took peak expiratory flow rate (PEFR) recordings. From children reporting a symptomatic episode or a decrease in PEFR, samples were taken for detection of viruses and atypical bacteria. A total of 232 respiratory viruses and four atypical bacteria were detected. The half-monthly rates of upper respiratory infection were compared with the half-monthly rates for hospital admissions for asthma (International Classification of Diseases [ICD] code 493) for the same time period for the hospitals serving the areas from which the cohort of schoolchildren was drawn. The relationships of upper respiratory infections and hospital admissions for asthma with school attendance were studied. Strong correlations were found between the seasonal patterns of upper respiratory infections and hospital admissions for asthma (r = 0.72; p < 0.0001). This relationship was stronger for pediatric (r = 0.68; p < 0.0001) than for adult admissions (r = 0.53; p < 0.01). Upper respiratory infections and admissions for asthma were more frequent during periods of school attendance (87% of pediatric and 84% of total admissions), than during school holiday periods (p < 0.001). These relationships remained significant when allowance was made for linear trend and seasonal variation using multiple regression analysis (p < 0.01). Not surprisingly, school attendance, because it is a major factor in respiratory virus transmission, was found to be a major confounding variable in children. This study demonstrates that upper respiratory viral infections are strongly associated in time with hospital admissions for asthma in children and adults. Rhinoviruses were the major pathogen implicated, and the majority of viral infections and asthma admissions occurred during school attendance.

Adolescent↗
PubMed1995

Genomic structure of an attenuated quasi species of HIV-1 from a blood transfusion donor and recipients.

A blood donor infected with human immunodeficiency virus-type 1 (HIV-1) and a cohort of six blood or blood product recipients infected from this donor remain free of HIV-1-related disease with stable and normal CD4 lymphocyte counts 10 to 14 years after infection. HIV-1 sequences from either virus isolates or patient peripheral blood mononuclear cells had similar deletions in the nef gene and in the region of overlap of nef and the U3 region of the long terminal repeat (LTR). Full-length sequencing of one isolate genome and amplification of selected HIV-1 genome regions from other cohort members revealed no other abnormalities of obvious functional significance. These data show that survival after HIV infection can be determined by the HIV genome and support the importance of nef or the U3 region of the LTR in determining the pathogenicity of HIV-1.

Adult↗
PubMed1995

Famciclovir for the treatment of acute herpes zoster: effects on acute disease and postherpetic neuralgia. A randomized, double-blind, placebo-controlled trial. Collaborative Famciclovir Herpes Zoster Study Group.

OBJECTIVE: To document the effects of treatment with famciclovir on the acute signs and symptoms of herpes zoster and postherpetic neuralgia. DESIGN: A randomized, double-blind, placebo-controlled, multicenter trial. SETTING: 36 centers in the United States, Canada, and Australia. PATIENTS: 419 immunocompetent adults with uncomplicated herpes zoster. INTERVENTION: Patients were assigned within 72 hours of rash onset to famciclovir, 500 mg; famciclovir, 750 mg; or placebo, three times daily for 7 days. MEASUREMENTS: Lesions were assessed daily for as long as 14 days until full crusting occurred and then weekly until the lesions healed. Viral cultures were obtained daily while vesicles were present. Pain was assessed at each of the visits at which lesions were examined and then monthly for 5 months after the lesions healed. Safety was assessed throughout the study. RESULTS: Famciclovir was well tolerated, with a safety profile similar to that of placebo. Famciclovir accelerated lesion healing and reduced the duration of viral shedding. Most importantly, famciclovir recipients had faster resolution of postherpetic neuralgia (approximately twofold faster) than placebo recipients; differences between the placebo group and both the 500-mg famciclovir group (hazard ratio, 1.7 [95% CI, 1.1 to 2.7]) and the 750-mg famciclovir group (hazard ratio, 1.9 [CI, 1.2 to 2.9]) were statistically significant (P = 0.02 and 0.01, respectively). The median duration of postherpetic neuralgia was reduced by approximately 2 months. CONCLUSIONS: Oral famciclovir, 500 mg or 750 mg three times daily for 7 days, is an effective and well-tolerated therapy for herpes zoster that decreases the duration of the disease's most debilitating complication, postherpetic neuralgia.

2-Aminopurine↗
PubMed1995

A report of intestinal sarcocystosis in the bullsnake (Pituophis melanoleucus sayi) and a re-evaluation of Sarcocystis sp. from snakes of the genus Pituophis.

We report a severe enteric infection of Sarcocystis sp. from a wild-caught bullsnake (Pituophis melanoleucus sayi). The animal was collected in October 1988 by a commercial dealer, imported into the United Kingdom during November 1988 and purchased by the London Zoo, in December 1988. The animal was not fed after capture and was anorexic from the time of purchase to the time of death in January 1989. On necropsy, the animal was emaciated and the mucosa of the proximal intestine was markedly thickened. The lamina propria was packed with oocysts, and enterocytes were parasitized by an organism which closely resembled Sarcocystis roudabushi and Sarcocystis idahoensis, two bisporocystid coccidia described previously from Pituophis melanoleucus. We propose that Sarcocystis idahoensis and Sarcocystis roudabushi are synonymous since both occur in the same host species, both invade the intestinal lamina propria and entreocytes, and sporocyst measurement ranges of both species overlap. This is the first report of death believed to be due to sarcocytosis in a naturally-infected definitive host.

Animals↗
PubMed1994

The effect of alpha 2 macroglobulin in commercial cytokine assays.

alpha 2 macroglobulin (alpha 2M), a 725 kDa plasma protein, has been reported to bind a range of cytokines. We have therefore investigated its effect on a number of commercial cytokine assays. The methylamine converted fast form of the molecule was found to reproducibly depress, by 26% or more, the standard curves obtained with certain commercial assays for IL-2 and for tumor necrosis factor alpha, and had a small inhibitory effect on some IL-4 assays. In contrast it slightly enhanced or had no effect on ELISAs for IL-1 beta and IL-6. The inhibition observed was directly proportional to the concentration of alpha 2 M used in the range 0.5-5 mg/ml. Studies in the IL-2 system also revealed that it was largely attributable to the fast form of alpha 2M. Preliminary evidence suggests that the effects observed may be dependent on the assay source. These findings may be relevant to the assay of biological fluids in which alpha 2 M is present.

Artifacts↗
PubMed1994

Thermostabilization of the Bacillus circulans xylanase by the introduction of disulfide bonds.

The thermostability of the 20 396 Da Bacillus circulans xylanase was increased by the introduction of both intra- and intermolecular disulfide bridges by site-directed mutagenesis. Based on the 3-D structure of the enzyme, sites were chosen where favourable geometry for a bridge existed; in one case, to obtain favourable geometry additional mutations around the cysteine sites were designed by computer modelling. The disulfide bonds introduced into the xylanase were mostly buried and, in the absence of protein denaturants, relatively insensitive to reduction by dithiothreitol. The mutant proteins were examined for residual enzymatic activity after various thermal treatments, and were assayed for enzymatic activity at elevated temperatures to assess their productivity. We have examined one of these mutants by X-ray crystallography. All of the disulfide bond designs tested increased the thermostability of the B. circulans xylanase, but not all enhanced the activity of the enzyme at elevated temperatures.

Bacillus↗
PubMed1994

Degradation of xenobiotic compounds in situ: capabilities and limits.

Exploiting microorganisms for remediation of waste sites is a promising alternative to groundwater pumping and above ground treatment. The objective of in situ bioremediation is to stimulate the growth of indigenous or introduced microorganisms in regions of subsurface contamination, and thus to provide direct contact between microorganisms and the dissolved and sorbed contaminants for biotransformation. Subsurface microorganisms detected at a former manufactured gas plant site contaminated with coal tars mineralized significant amounts of naphthalene (8-43%) and phenanthrene (3-31%) in sediment-water microcosms incubated for 4 weeks under aerobic conditions. Evidence was obtained for naphthalene mineralization (8-13%) in the absence of oxygen in field samples. These data suggest that biodegradation of these compounds is occurring at the site, and the prospects are good for enhancing this biodegradation. Additional batch studies demonstrated that sorption of naphthalene onto aquifer materials reduced the extent and rate of biodegradation, indicating that desorption rate was controlling the biodegradation performance.

Bacteria, Aerobic↗
PubMed1994

Isolation of a new foamy retrovirus from orangutans.

We have isolated a new foamy virus from blood samples taken from two apparently healthy orangutans (Pongo pygmaeus). The older orangutan has since died with encephalopathy after a brief acute illness, while the younger one, his grandson, remains well. These animals and 12 other orangutans had specific antibodies to foamy virus as measured by immunofluorescence. The new foamy virus and the antisera showed strong and specific neutralization, with only weak cross-reaction with other simian foamy virus strains. Southern blotting with gag and env probes of human foamy virus and PCR amplification showed that the new foamy virus, designated SFV-11, is related to, yet distinct from, previously characterized strains from humans, chimpanzees, and monkeys.

Animals↗
PubMed1994

Evolution of alanine:glyoxylate aminotransferase 1 peroxisomal and mitochondrial targeting. A survey of its subcellular distribution in the livers of various representatives of the classes Mammalia, Aves and Amphibia.

As part of a wider study on the molecular evolution of alanine:glyoxylate aminotransferase 1 (AGT1) intracellular compartmentalization, we have determined the subcellular distribution of immunoreactive AGT1, using postembedding protein A-gold immunoelectron microscopy, in the livers of various members of the classes Mammalia, Aves, and Amphibia. As far as organellar distribution is concerned, three categories could be distinguished. In members of the first category (type I), all, or nearly all, of the immunoreactive AGT1 was concentrated within the peroxisomes. In the second category (type II), AGT1 was found more evenly distributed in both peroxisomes and mitochondria. In the third category (type III), AGT1 was localized mainly within the mitochondria with much lower, but widely variable, amounts in the peroxisomes. Type I animals include the human, two great apes (gorilla, orangutan), two Old World monkeys (anubis baboon, Japanese macaque), a New World monkey (white-faced Saki monkey), a lago, morph (European rabbit), a bat (Seba's short-tailed fruit bat), two caviomorph rodents (guinea pig, orange-rumped agouti), and two Australian marsupials (koala, Bennett's wallaby). Type II animals include two New World monkeys (common marmoset, cotton-top tamarin), three prosimians (brown lemur, fat-tailed dwarf lemur, pygmy slow loris), five rodents (a hybrid crested porcupine, Colombian ground squirrel, laboratory rat, laboratory mouse, golden hamster), an American marsupial (grey short-tailed opossum), and a bird (raven). Type III animals include the large tree shrew, three insectivores (common Eurasian mole, European hedgehog, house shrew), four carnivores (domestic cat, ocelot, domestic dog, polecat ferret), and an amphibian (common frog). In addition to these categories, some animals (e.g. guinea pig, common frog) possessed significant amounts of cytosolic AGT1. Whereas the subcellular distribution of AGT1 in some orders (e.g. Insectivora and Carnivora) did not appear to vary markedly between the different members, in other orders (e.g. Primates, Rodentia and Marsupialia) it fluctuated widely between the different species. Phylogenetic analysis indicates that the subcellular distribution of AGT1 has changed radically on numerous occasions during the evolution of mammals. The new observations presented in this paper are compatible with our previous demonstration of a relationship between AGT1 subcellular distribution and either present or putative ancestral dietary habit, and our previous suggestion that the molecular evolution of the AGT gene has been markedly influenced by dietary selection pressure.

Alanine Transaminase↗
PubMed1993

Secondary substrate binding in aspartic proteinases: contributions of subsites S3 and S'2 to kcat.

The kinetic parameters kcat and Km were determined at 25 degrees C and pH 5.5 for endothiapepsin and rhizopuspepsin acting on the series of substrates Ac-Ala(m)-Lys-Nph-Ala(n)-amide where Nph is p-nitrophenylalanine, and m and n equal 0-4. Kinetic parameters were also determined at 25 degrees C and pH 3.5 for pig pepsin acting on the series of substrates Ac-Ala(m)-Phe-Nph-Argn-Ala(n)-amide, where m equals 0 to 2 and n equals 0 or 1, and another series based on -Ile-Glu-Phe-Nph-Arg-, which is the core of a series of peptides designed by Dunn et al. (1986, Biochem. J. 237, 899-906). Km values were found to be largely independent of increases in the chain length of the substrates whereas kcat values showed large increases with increasing chain length. With endothiapepsin and rhizopuspepsin the largest increases (between 13-fold and over 150-fold) were obtained when alanine residues were added in positions P3 and P'2 and thus are similar to those observed previously with penicillopepsin. Additions of alanines to positions P2, P'3, and P'4 gave much smaller increases. In the case of pig pepsin the results were not as clearcut. Whereas the largest increases were seen for positions P3 and P'2 only with some of the peptides, the increases were strongly dependent on the length of the peptides. With some of the longer peptides the increases were comparable to those seen for positions P2 and P'3. Thus, whereas the addition of two alanines in position P3 to the dipeptide Ac-Phe-Nph-amide caused a large proportional increase in kcat, the increase was much smaller when the addition was made to the homologous tetrapeptide and even smaller when made to the pentapeptide Ac-Ala-Phe-Nph-Arg-Ala-amide. Additions of arginine in position P'2 gave large increases in kcat for all three peptides of the series.

Amino Acid Sequence↗
PubMed1992

Long-term symptomless HIV-1 infection in recipients of blood products from a single donor.

There have been reported cases of long-term symptomless human immunodeficiency virus type 1 (HIV-1) infection, but it is not clear whether the benign course of infection was due to host, viral, or other unknown factors. During follow-up of subjects with transfusion-acquired HIV-1 infection in New South Wales, Australia, we identified a group of 6 subjects who had been infected through a single common donor. We were therefore able to study the contributions of various factors to the course of infection. Throughout follow-up (range 6.8-10.1 years after infection), 5 of the recipients and the donor (last follow-up 10.2 years after infection of the first recipient) remained clinically free of symptoms, with normal CD4 cell counts and no p24 antigenaemia. HIV-1 was isolated from only 1 recipient; the isolate did not induce syncytia in a SUPT1 co-culture assay and had a limited in-vitro host range. 1 infected recipient (who had received extensive immunosuppressive treatment for systemic lupus erythematosus) developed Pneumocystis carinii pneumonia and died 4.3 years after infection. The frequency of progression to AIDS or a CD4 cell count below 0.50 x 10(9)/l was significantly lower among the 6 subjects with a common donor (1/6) than among 101 other HIV-infected transfusion recipients for whom data from 7 years of follow-up were available (94/101; p less than 0.0001). These findings suggest that the subjects were infected by a less virulent strain of HIV-1. The identification of this group of subjects should stimulate a search for other similar groups, which will provide important information on the immunopathogenesis of HIV-1 disease.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Molecular cloning and primary structure of the avian Thy-1 glycoprotein.

We have previously characterised, both biochemically and immunohistochemically, a 23 kDa putative avian Thy-1 protein homologue. In this report we have examined the carbohydrates present on the protein and determined the partial protein sequence of enzymatically and CNBr-produced peptides. The protein sequences enabled us to clone an essentially full-length (1854 bp) cDNA using PCR and colony screening of an embryonic day (ED) 18 forebrain pUEX-1 cDNA library. Analysis of deduced amino acid sequence shows the 23 kDa protein to be 110 amino acids in length compared to mouse (112) and human and rat (111) while still retaining the conserved cysteine residues. The N-glycosylation site at position 61 is the same as that in the human protein, but is different from that in the rodent (position 75). Northern blot analysis of Thy-1 mRNA expression in the forebrain, cerebellum and tectum show that all three tissues have low levels at ED4 (forebrain and tectum) and ED8 (cerebellum), rising most rapidly between ED16 and the first few days post-hatch. Analysis of various tissues at hatch and adult show expression to be predominantly neuronal with very low levels in some other organs, mainly at hatch, indicating the possibility of subsets of cells, which we have also seen in histological sections, in these tissues expressing Thy-1 mRNA. Bone marrow and blood cells were also negative for Thy-1 protein.

Aging↗
PubMed1992

Acute phenobarbital intoxication.

Phenobarbital is a long-acting barbiturate often prescribed for seizure disorders. It has a high abuse potential and was commonly used in suicide attempts in the past. Although benzodiazepines are now more frequently used in suicide attempts, barbiturate intoxications are still occasionally seen and constitute a medical emergency. The management of phenobarbital overdose includes cardiac and respiratory support, cathartics, activated charcoal, and alkaline diuresis. In severely compromised patients, hemodialysis and hemoperfusion can be used to enhance drug clearance.

Drug Overdose↗