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Biomedical subjects

B J Stewart

Publications and source records attributed to B J Stewart.

50 records · Page 3Linked to original sources
PubMed1983

Botulism in New South Wales, 1980-1981.

The isolation of Clostridium botulinum from the home environment of New South Wales patients with infant botulism is reported. Of the three cases of infant botulism type B, the bacteria were isolated from soil around the dwelling in one, and from tank rainwater in another. In one case with type A, the bacteria were present in the soil, vacuum-cleaner dust, and tank rainwater. The bacteria were not detected in the environment of two adult patients and a child with C. botulinum in their stools. The home location of the patients with infant botulism, and the frequency of isolation of the bacteria from rainwater, soil and vacuum-cleaner dust in Cobar, Nyngan, some Sydney suburbs, and at five pastoral homesteads suggest that infants in rural areas are more at risk than those in large metropolitan areas. The age of the infants with diagnosed botulism in New South Wales, compared with those reported in the United States data, strongly suggests that the disease is not being fully recognised in younger infants.

Aged↗
PubMed1983

Type C botulism in young dogs.

A diffuse lower motor neurone paralysis developed in a 6-month-old male Australian cattle dog pup 4 days after it had eaten the carcase of a rotting duck in Centennial Park, Sydney. Two other dogs which ate smaller portions of the same carcase were less severely affected. Clostridium botulinum type C was isolated from and C. botulinum type C toxin was detected in faeces from the severely affected dog. The serum contained 25 LD50 of toxin/ml. The high C. botulinum count and toxin level in the faeces declined progressively during the ensuing weeks, but 114 days after ingesting the carcase C. botulinum type C was still present in faeces and a low toxin titre persisted. Soil, mud and water samples in the area of the duck ponds in the park contained C. botulinum type C spores. Spores and high toxin titres were also found in the intestine of the carcases of 2 birds in the area.

Animals↗
PubMed1980

Infant botulism.

Explore the source record for details and available documents.

Botulism↗
PubMed1980

Rapid radiometric method for detection of Salmonella in foods.

A radiometric method for the detection of Salmonella in foods has been developed which is based on Salmonella poly H agglutinating serum preventing Salmonella from producing 14CO2 from [14C]dulcitol. The method will detect the presence or absence of Salmonella in a product within 30 h compared to 4 to 5 days by routine culture methods. The method has been evaluated against a routine culture method using 58 samples of food. The overall agreement was 91%. Five samples negative for Salmonella by the routine method were positive by the radiometric method. These may have been false positives. However, the routine method may have failed to detect Salmonella due to the presence of large numbers of lactose-fermenting bacteria which hindered isolation of Salmonella colonies on the selective agar plates.

Animals↗
PubMed1978

A reliable test for differentiation and presumptive identification of certain clinically significant anaerobes.

A modification of the slide catalase test was evaluated to determine its reliability for the presumptive identification of certain anaerobic gram-negative and gram-positive organisms isolated from clinical specimens. A total of 650 fresh isolates was evaluated. Growth from a trypticase blood agar plate or Schaedler's agar with laked blood was transferred to a slide and a drop of 15% H2O2 with Tween 80 added. Veillonella alcalescens, Proprionibacterium species, Peptococcus species, and Bacteroides fragilis, B. thetaiotaomicron, B. distasonis, B. ovatus, and B. vulgatus were positive by this method. Comparative slide and tube catalase tests were performed with the above-mentioned bacteroides species by growing each isolate on trypticase soy agar, Brucella agar, brain-heart infusion agar, each with and without added hemin, and on Schaedler's agar. Four solutions of H2O2 were used, 3 and 15%, and 3 and 15% with Tween 80. The addition of Tween 80 to H2O2 increased the sensitivity of the reaction with both slide and tube methods. The 15% H2O2 with Tween 80 consistently gave the most rapid and persistent positive reaction. A slide catalase test in combination with a Gram stain should be performed on each anaerobic isolate; this would significantly decrease the time required for presumptive identification of many anaerobic organisms.

Bacteria↗
PubMed1976

Derepressed synthesis of cellulase by Cellulomonas.

A Cellulomonas sp. was isolated from the soil which hydrolyzed cellulose, as shown by clear-zone formation on cellulose agar medium. Catabolite repression of cellulase synthesis occurred when moderate levels of glucose were added to the medium. A stable mutant that no longer exhibits catabolite repression was produced through treatment of the wild-type organism with N-methyl-N'-nitro-N-nitrosoguanidine. Both enzyme concentration and specific activity, as determined by the rate of hydrolysis of carboxymethylcellulose, were greater with the mutant than with the wild-type organism under various test conditions. The wild type had no measurable cellulase activity when grown in the presence of either 1.0% glucose or cellobiose. Cellobiose, but not glucose, inhibited enzyme activity towards both cellulose and carboxymethylcellulose. Cellobiose, cellulose, and sophorose at low concentrations induced cellulase synthesis in both the wild-type and the mutant organism. Cellulase regulation appears to depend upon a complex relationship involving catabolite repression, inhibition, and induction.

Actinomycetales↗
PubMed1976

Comparison of API and Minitek to Center for Disease Control methods for the biochemical characterization of anaerobes.

Two commercially available micromethod multitest systems (API, Analytab Products, Inc., Minitek-Bioquest) were compared with conventional tests suggested by the Center for Disease Control for the identification of anaerobes. Anaerobiosis for the microsystems was achieved using GasPak system (BBL), A total of 175 anaerobes, including 158 clinical isolates and 17 reference strains, were used. Gram morphology, gas-liquid chromatography data, and biochemical reactions from the Center for Disease Control and Virginia Polytechnic Institute anaerobic manuals were used to identify the organisms. The Minitek system included a new anaerobe inoculum broth and two new disks, dextrose without nitrate and nitrate reductase disks. The percentage of correlation of 12 biochemicals using Minitek and 11 biochemicals using the API were compared with the Center for Disease Control reactions. The percentage of correlation of both positive and negative reactions with the API anaerobic strip ranged from 70.8 to 99.4% and with the Minitek from 97.1 to 100%. The microsystems were also evaluated as to the ease of use, adaptabilty to a clinical laboratory, time, and cost.

Anaerobiosis↗
PubMed1970

A survey of hemoglobin values in Canada.

A compilation of hemoglobin values has been made from submissions from laboratories in Canada using the cyanmethemoglobin standard prepared and distributed by the Canadian Communicable Disease Centre (formerly the Laboratory of Hygiene). From 84 participating laboratories 21,580 values were analyzed statistically by age and sex. "Medical referrals", exclusive of blood dyscrasias, were included but were documented separately from "well persons". In most age groupings no significant difference in these two categories was found.Values for boys and girls were similar up to 12 years of age. For adult women from 18 to 84 years the mean value was 13.0 g. per 100 ml. (95% confidence limits 10.8-15.2 g.); for pregnant women 19 to 44 years the mean value was 12.2 g. per 100 ml. (9.7-14.6 g.). For men aged 17 to 24 years the mean value was 15.0 g. per 100 ml. (12.8-17.3 g.); 25-49 years 14.6 g. per 100 ml. (12.4-16.9 g.); 50-69 years 14.3 g. per 100 ml. (11.8-16.8 g.). It is noteworthy that for the most part the mean values were slightly lower than those frequently quoted as "normal" and that the mean values, particularly for the male, were lower with increasing age.

Adolescent↗
PubMedDate not supplied

Health status of bereaved parents.

Forty-seven mothers and 33 fathers, representing 48 families, participated in a propective longitudinal study of the effects on family members of a child's dying. The purpose of this article is to describe parents' health during the terminal illness of their child and during the first year following their child's death from cancer. The Duke-UNC Health Profile was used to examine parents' health prior to and at three points in thime after the child's death. The bereavedparents' general health was compared to the health of normative sample of adults. The findings indicate that parents' health is not adversely affected by a child's death from cancer.

Adolescent↗
PubMedDate not supplied

pH and concentration of bilirubin in feeding tube aspirates as predictors of tube placement.

BACKGROUND: Currently available bedside methods for determining feeding tube placement often provide inconclusive results. Therefore, additional data are needed to assist nurses in making decisions regarding tube location. OBJECTIVES: To describe the usual concentration of bilirubin in aspirates from newly inserted feeding tubes and to determine the extent to which these measures can contribute to pH alone in correctly predicting feeding tube location. METHODS: Gastrointestinal samples for concurrent pH and bilirubin testing were obtained from adult, acutely ill patients with newly inserted small-bore feeding tubes (nasogastric, n = 209; nasointestinal, n = 228) within 5 minutes of radiographs taken to determine tube location. Respiratory samples were tested (tracheobronchial, n = 126; pleural, n = 24). pH was measured with a pH meter, and bilirubin content was assayed spectrophotometrically. Results from the pH and bilirubin tests were compared with tube location as determined by radiography. RESULTS: Mean pH levels in the lung (7.73) and intestine (7.35) were significantly higher than the mean pH level in the stomach (3.90; p < .001 for each comparison). Mean bilirubin levels in the lung (.08 mg/dl) and stomach (1.28 mg/dl) were significantly lower than the mean bilirubin level in the intestine (12.73 mg/dl; p < .001 for each). By visually inspecting distribution overlap and mean differences by tube site, results were dichotomized so that a combination of pH and bilirubin values could be used to develop a predictive algorithm. A pH of >5 and a bilirubin value of <5 mg/dl correctly identified all respiratory cases, whereas a pH >5 coupled with a bilirubin level of > or =5 mg/dl correctly identified three fourths of the intestinal cases. A pH of < or =5 coupled with a bilirubin value of <5 correctly identified more than two thirds of the gastric cases. CONCLUSIONS: Preliminary laboratory-based data indicate that appropriate use of the proposed algorithm could significantly reduce the number of x-rays needed to exclude respiratory placement and to distinguish between gastric and intestinal placement.

Adolescent↗
PubMedDate not supplied

Development of a reliable and valid bedside test for bilirubin and its utility for improving prediction of feeding tube location.

BACKGROUND: The addition of laboratory bilirubin readings to an algorithm based on pH alone improves prediction of feeding tube location; although reliable pH-teststrips are available, there is no bedside test to measure bilirubin in feeding tube aspirates. OBJECTIVES: This study was designed to test the efficacy of a bilirubin teststrip with a newly developed scale in measuring the bilirubin content in feeding tube aspirates, and to determine the effectiveness of a combination of readings from pH and bilirubin teststrips in predicting feeding tube location. METHODS: A total of 631 gastrointestinal specimens for concurrent pH and bilirubin testing were obtained from adult, acutely ill patients with newly inserted feeding tubes (nasogastric, n = 328; nasointestinal, n = 303) within 5 minutes of radiographs taken to determine tube location. In addition, 225 respiratory specimens were tested. Bilirubin was measured with a teststrip incorporating a newly developed colorimetric visual bilirubin (VBIL) scale, and by a laboratory assay. pH was measured with a teststrip and a pH-meter. Results from the bilirubin and pH tests were read by research assistants and staff nurses and compared with tube location as determined by radiography. RESULTS: The correlation between readings made from the 5-point VBIL scale and the trimmed laboratory bilirubin was 0.93, with dichotomized readings correlating 0.87 and kappa equal to 0.86. A pH greater than 5 and a bilirubin less than 5 mg/dL successfully identified 100% of the 225 respiratory cases. In the category of pH 5 or less and bilirubin less than 5 mg/dL, 98% of the cases were gastric cases. In the category of pH greater than 5 and bilirubin 5 or higher mg/dL, nearly 88% of the cases were intestinal cases. CONCLUSIONS: The newly developed VBIL scale is effective in determining the bilirubin content in feeding tube aspirates. Furthermore, compared with predicting tube location from pH-paper alone, dichotomized readings from the VBIL scale/bilirubin teststrip used in combination with a pH-teststrip improved the ability to differentiate between respiratory and gastrointestinal tube placement, as well as between gastric and intestinal tube placement. Refinement of the VBIL scale is indicated to increase its accuracy.

Adolescent↗
PubMedDate not supplied

pH and concentrations of pepsin and trypsin in feeding tube aspirates as predictors of tube placement.

BACKGROUND: The purpose of this study was to determine the extent to which pepsin and trypsin concentrations in feeding tube aspirates, in addition to pH, contribute to predicting feeding tube position. METHODS: Aspirates from 742 feeding tubes (nasogastric, n = 343; nasointestinal, n = 399) were tested for pH and enzyme concentrations. Also tested were aspirates from two feeding tubes inadvertently positioned into the lung (one in the pleural space and one in the tracheobronchial tree) and 146 samples of tracheobronchial and pleural fluids collected by other methods. Enzyme assays were conducted in a research laboratory. Results of the pH and enzyme tests were compared with radiologic reports of tube location. RESULTS: Gastric fluid had a mean low pH (4.06), a high mean pepsin concentration (349.1 micrograms/mL), and a low mean trypsin concentration (19.3 micrograms/mL). In contrast, intestinal fluid had a mean high pH (7.40), a high mean trypsin concentration (143.0 micrograms/mL), and a low mean pepsin concentration (24.2 micrograms/mL). Respiratory samples also had a high mean pH (7.89) but contained little or no pepsin or trypsin. Using a logistic regression equation with all three variables to differentiate between respiratory and gastrointestinal placement, it was possible to correctly classify 100% of the respiratory cases and 93.4% of the gastrointestinal cases. Another equation used to differentiate between gastric and intestinal sites was able to classify correctly 91.2% of the gastric cases and 91.5% of the intestinal cases. CONCLUSIONS: The results clearly indicate that laboratory-determined enzyme concentrations in feeding tube aspirates are helpful in predicting tube location. Thus, it is desirable that inexpensive, simple bedside tests be developed so that they can be used in conjunction with pH measurements to help predict tube position.

Enteral Nutrition↗