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Biomedical subjects

J Beaman

Publications and source records attributed to J Beaman.

12 recordsLinked to original sources
PubMed1996

Parents and peer group as mediators of the effect of community structure on adolescent problem behavior.

Used a sample of 207 single-parent families residing in 104 small, Midwestern communities to test hypotheses regarding the link between community context and adolescent conduct problems and psychological distress. For boys, community disadvantage had a direct affect on psychological distress, while it indirectly boosted the probability of conduct problems by disrupting parenting and increasing affiliation with deviant peers. Community disadvantage was unrelated to the deviant behavior or emotional well-being of girls. Proportion of single-parent households in the community had a direct effect on girls' conduct problems. It also contributed indirectly to girls' conduct problems by increasing the probability of involvement with deviant peers. Possible explanations for these gender differences are provided.

Adolescent↗
PubMed1995

A new data model for biological classification.

In the domain of biological classification, classifications are performed hierarchically. There are no standard classifications which are unanimously accepted by the community of each domain; many different interacting views of classification exist about the same data, and the discovery of new data results in changes to the existing classification. Even a single individual may change his or her own classification of a particular group. Since multiple classification views interact, they are semantically related. It is difficult to model this kind of dynamically evolving and semantically interacting classification system using traditional data models, which lack the structural flexibility necessary to support dynamic views of hierarchic classifications, and cannot properly capture the history of these complex interactions. We have developed a new data model which is suitable for supporting semantically interacting dynamic views of hierarchic biological classifications. On the basis of our new data model we have developed a prototype database system called HICLAS (HIerarchical CLAssification System); its domain is plant taxonomy. HICLAS is available through the Internet and an X-window interface has been implemented to support queries to classification data.

Classification↗
PubMed1995

Filter paper cortisol profiles in secondary adrenocortical insufficiency.

The use of filter paper four point 24 hour cortisol profiles in the diagnosis and management of secondary adrenocortical deficiency was examined. Eighteen children with familial short stature and isolated growth hormone deficiency had normal 24 hour and morning plasma cortisol concentrations measured. Eight of 11 children with multiple pituitary hormone deficiencies had evidence of hypocorticalism despite previously normal baseline cortisols or responses to insulin hypoglycaemia or tetracosactrin. Nine of 11 children with hypopituitarism on replacement treatment (4.9-12.5 mg/m2/day) had satisfactory concentrations of cortisol, though morning cortisols were often low. Filter paper profiles are a simple, inexpensive, and relatively non-invasive way of managing children with suspected hypocorticalism and of monitoring their treatment.

Adolescent↗
PubMed1989

The evaluation of a chemiluminescent assay for free thyroxine by comparison with equilibrium dialysis in clinical samples.

We have investigated the diagnostic performance of a chemiluminescence immunoassay for free thyroxine (Ciba Corning Magic Lite) in comparison with equilibrium dialysis. Agreement between the methods was satisfactory across a wide range of samples including those from patients with non-thyroidal illness. The results suggest that the chemiluminescence immunoassay is not subject to the artefacts of widely used analogue tracer methods for free thyroxine estimation.

Adolescent↗
PubMed1986

Comparison of direct plating with the use of enrichment culture for isolation of Aeromonas spp. from faeces.

Direct plating of faecal specimens on blood agar was compared with the use of enrichment culture for isolation of Aeromonas spp. from faeces during a large epidemiological study. Of enterotoxigenic strains isolated by direct plating, 89% were associated with acute diarrhoea and 7% with an episode of diarrhoea during the month before collection, but 79% of enterotoxigenic strains isolated only after enrichment were not associated with acute diarrhoea. With Aeromonas spp., as with intestinal pathogens, it appears that enrichment allows isolation of the bacteria when in low faecal concentrations likely to be found in convalescent patients, carriers and those with subclinical infection. The routine use of enrichment for isolation of faecal aeromonads, by detecting Aeromonas spp. in low numbers in patients without diarrhoea, is likely to confuse interpretation of epidemiological studies seeking to clarify the relationship between Aeromonas spp. and acute diarrhoea.

Aeromonas↗
PubMed1984

Media for isolation of Aeromonas spp. from faeces.

Five solid media were evaluated for isolation of Aeromonas spp. from faeces: desoxycholate citrate agar (DCA), MacConkey's agar (MAC), xylose-desoxycholate-citrate agar (XDCA), Rogol's medium (ROG), which contained ampicillin 20 mg/L and p-nitrophenyl-glycerine 25 mg/L as inhibitors, and blood agar (BA) with ampicillin 10 mg/L. False negative oxidase tests limited the usefulness of DCA and MAC and, although the use of XDCA avoided the problem of fermentation of lactose, some Aeromonas spp. failed to grow on XDCA or produced minute colonies unsuitable for oxidase tests. BA yielded the highest rate of isolation for Aeromonas spp. from 323 faecal samples--15.2% for all Aeromonas spp. and 9.3% for enterotoxigenic (ENT+) strains. This compares with 10.8% for all strains and 6.5% for ENT+ strains isolated on DCA, 7.1% for all strains and 4% for ENT+ strains on MAC and 4% for all strains and 1.5% for ENT+ strains on ROG. Blood agar with ampicillin is recommended for isolation of Aeromonas spp. from faeces.

Aeromonas↗
PubMed1984

Biotyping and virulence factors in clinical and environmental isolates of Aeromonas species.

Biochemical characteristics and virulence factors were compared in 147 Aeromonas spp. isolated from patients with diarrhea and in 94 strains isolated from metropolitan water supplies in the same area during the same period. Fermentation of arabinose occurred with 58.5% of the environmental strains and 15% of the clinical isolates; 39.4% of the strains from water and 6.8% of the fecal isolates fermented salicin. The frequency of esculin hydrolysis was the same in both groups. Ninety-one percent of clinical isolates and 70.2% of environmental strains were enterotoxigenic and, except for four clinical isolates, all of these strains also produced hemolysins. Hemagglutination that was inhibited by fucose and mannose but not by galactose was found in 67% of the water isolates and 10.2% of the clinical strains. Although the distribution of several characteristics differs in clinical and environmental strains, many of the strains found in water have properties identical with those of the clinical isolates. We suggest that such strains may be potential enteric pathogens.

Aeromonas↗
PubMed1983

The microbiology of childhood gastroenteritis: Aeromonas species and other infective agents.

A prospective, 12-month study of 975 non-Aboriginal children with diarrhea and age- and sex-matched children without diarrhea, in Perth, Western Australia, was designed to investigate the significance of enterotoxigenic Aeromonas species as a cause of diarrhea. Enterotoxigenic Aeromonas species were found in the fecal specimens of 10.8% of the patients with diarrhea but in only 0.7% of those without diarrhea. Most Aeromonas species were isolated during the summer. Other important bacterial pathogens included Campylobacter, Salmonella, Shigella, and enterotoxigenic Escherichia coli; rotavirus infections appeared to be much less important in the Western Australian environment. Most of the patients were younger than two years of age and about one-quarter had mixed bacterial and/or viral intestinal infections. Enterotoxigenic Aeromonas species can be identified with 97% accuracy using a simple hemolysin assay which should be considered for use by routine diagnostic laboratories, particularly in children's hospitals.

Aeromonas↗
PubMed1983

Correlation of enterotoxicity with biotype in Aeromonas spp.

Enterotoxin production correlated with biotype in a study of 686 strains of Aeromonas spp. from Indonesia, Thailand, the United States, and Western Australia. Most strains were isolated from feces but nonfecal human isolates and environmental strains were also included. More than 80% of Voges-Proskauer (VP)-positive strains, classified as A. hydrophila, were enterotoxigenic in the suckling mouse assay as were 90% of VP-positive, arabinose-negative strains. An association between positive VP, arabinose fermentation, and failure to produce enterotoxins was found only with environmental strains. VP-negative strains which did not oxidize gluconate or produce gas from glucose were classified as A. punctata subsp. caviae. Only 2 of the 286 strains produced enterotoxins, and both were from Indonesian fecal samples. There were few remaining VP-negative strains, classified as A. punctata subsp. punctata and, of these, about half were enterotoxigenic. Regardless of source and species, 97% of Aeromonas spp. were correctly classified in relation to enterotoxin production with a hemolysin assay. A combination of biochemical testing and hemolysin assay should be suitable for diagnostic laboratories to identify enterotoxigenic Aeromonas spp. which, in children, are associated with diarrhea, unlike non-enterotoxigenic strains.

Aeromonas↗
PubMed1979

Oropharyngeal microflora in Aboriginal and non-Aboriginal Australian children. An indicator of environmental contamination.

Faecal microorganisms, not normally resident in the oropharynx, were isolated much more often from Aboriginal than non-Aboriginal Australian children. This is almost certainly due to differences in standards of hygiene and living in these two groups, and is an important factor in contributing to the common and serious problem of gastrointestinal infections in young Aborigines. In the non-Aboriginal group, the isolations of faecal organisms were much more common from infants and from children under the age of two years when compared with older children; this is probably due to the readiness of spreading microorganisms from the gastrointestinal tract to the mouth in the younger children.

Australia↗
PubMed1977

Effects of biliary diversion on intestinal microflora in the rat.

Certain bile acids inhibit the growth in vitro of organisms commonly found in the intestine and, in particular, anaerobic bacteria. As the importance of this effect in vivo has not been demonstrated, we investigated changes in intestinal flora in the rat after diversion of bile to the urinary bladder. Five days after operation there was an increase in numbers of Proteus sp. in the stomach, mid-jejunum and caecum and of coliform bacilli in the stomach and mid-jejunum. Lacto-bacilli were increased in the stomach. There was no change in numbers of anaerobic organisms. Similar changes in bacterial flora followed 5 days of pair feeding in control rats. Our results do not suggest a specific antibacterial effect of bile salts in the rat in vivo. The changes found are probably related to semi-starvation, because the food intake of the rats after operation was about half that of control rats having an unrestricted diet.

Anaerobiosis↗