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Biomedical subjects

A Lee

Publications and source records attributed to A Lee.

At least 739 records · Page 41Linked to original sources
PubMed1982

Evidence for opioid and non-opioid forms of stimulation-produced analgesia in the rat.

This study compares stimulation-produced analgesia (SPA) elicited from two different midline regions of the midbrain of the rat. Dorsal electrode placements were in the caudal periaqueductal gray matter; ventral placements lay within or subjacent to the dorsal raphe n. SPA thresholds were measured by the tail-flick method both during and immediately after the period of brain stimulation. Thresholds were consistently higher in the post-stimulation test. SPA from dorsal and ventral regions differed in the following ways: (1) Post-stimulation analgesia was significantly more difficult to obtain in ventral than in dorsal regions, whereas during-stimulation analgesia did not vary as a function of electrode location; (2) Although a continuous distribution of thresholds was seen for ventral placements, thresholds for dorsal placements tended to be either high or low on both during- and post-stimulation tests; (3) Naloxone (0.01--10 mg/kg) reliably elevated SPA thresholds for ventral but not dorsal stimulation placements. We conclude that different substrates of SPA lie in close proximity to one another in the medial midbrain of the rat. This portion of the midbrain appears to mediate both opioid and non-opioid mechanisms of analgesia.

Analgesia↗
PubMed1982

Clostridia isolated from the feces of infants during the first year of life.

Clostridia isolated from the feces of ten healthy infants during the first year of life were identified. All infants excreted clostridia during the first week of life; the most common species were Clostridium butyricum, C. paraputrificum, and C. difficile. In the formula-fed infants colonization occurred consistently throughout the year, whereas in some breast-fed infants it was inhibited until weaning. The species isolated most frequently throughout the year were C. paraputrificum, C. butyricum, C. ramosum, C. sartagoformum, and C. perfringens. Of the species often found in infants, C. butyricum, C. difficile, and C. sartagoformum occur rarely in adults, reflecting differences in the environmental conditions in the gut of the two age groups. The mechanism by which environmental conditions select species of clostridia is unknown but may be important to our understanding of a variety of clostridial intestinal infections. It was demonstrated that species of clostridia which have been implicated in the etiology of neonatal necrotizing enterocolitis form part of the normal infant gastrointestinal microflora.

Breast Feeding↗
PubMed1982

The bacterial colonization of the large bowel of pre-term low birth weight neonates.

The bacterial colonization of the large bowel of 11 pre-term, low birth weight neonates who were nourished by expressed breast milk was examined by culturing serial faecal samples and compared to that observed in eight breast-fed and seven formula-fed full-term neonates. Pre-term neonates were colonized by high counts of facultatively anaerobic bacteria from the first days of life while bifidobacteria colonized only six babies during the first week and appeared in only one baby before day 5. Bacteroides spp. and clostridia were isolated from seven and six pre-term babies respectively during week 1 and were first observed on day 2. The intestinal colonization of pre-term infants differed from that in full-term breast-fed infants in the high counts of facultatively anaerobic bacteria and late appearance of bifidobacteria, and from both groups of full-term infants in the early stable colonization by Bacteroides spp. It is postulated that the composition of the normal intestinal microflora of pre-term low birth weight babies contributes to their predisposition to neonatal necrotizing enterocolitis. Results are discussed in relation to the effect of infant feeding regimens on intestinal microbial populations.

Actinomycetaceae↗
PubMed1982

Improving communication of microbiology test results.

A number of basic guidelines for the reporting of microbiological data are presented. These guidelines were generated as part of a project investigating the communication gap between the microbiology laboratory and the clinician. A series of interviews and workshops were held with senior medical and microbiology staff from a number of major hospitals. A major finding of this project was that insufficient time was considered to be given to the reporting of laboratory data compared to generation of that data; also, the laboratory should take greater responsibility for interpretative comments. These guidelines are presented as a basis for review of laboratory reporting practices.

Attitude of Health Personnel↗
PubMed1982

The microbial ecology of the large bowel of breast-fed and formula-fed infants during the first year of life.

The succession of bacterial populations in the large bowel of seven breast-fed and seven formula-fed infants was examined during the first year of life. The composition of the intestinal microflora varied according to the infant's diet. During the first week of life breast-fed and formula-fed infants were colonised by enterobacteria and enterococci followed by bifidobacteria, Bacteroides spp., clostridia and anaerobic streptococci. From week 4 until solid foods were given, breast-fed babies had a simple flora consisting of bifidobacteria and relatively few enterobacteria and enterococci. Formula-fed babies during the corresponding period were more often colonised by other anaerobes in addition to bifidobacteria and had higher counts of facultatively anaerobic bacteria. The introduction of solid food to the breast-fed infants caused a major disturbance in the microbial ecology of the large bowel as counts of enterobacteria and enterococci rose sharply and colonisation by Bacteroides spp., clostridia and anaerobic streptococci occurred. This was not observed when formula-fed infants began to take solids; instead, counts of facultative anaerobes remained high while colonisation by anaerobes other than bifidobacteria continued. At 12 months, the anaerobic bacterial populations of the large bowel of breast-fed and formula-fed infants were beginning to resemble those of adults in number and composition and there was a corresponding decrease in the number of facultative anaerobes. These changes are discussed in relation to changes in susceptibility to gastro-intestinal infection.

Actinomycetaceae↗
PubMed1982

Differentiation of subtypes within Leptospira interrogans serovars Hardjo, Balcanica and Tarassovi, by bacterial restriction-endonuclease DNA analysis (BRENDA).

Various strains of Leptospira interrogans were compared by bacterial restriction-endonuclease DNA analysis (BRENDA). Field strains of serovar hardjo isolated from domestic animals in New Zealand, Australia and Northern Ireland were indistinguishable from one another but differed strikingly from the hardjo reference strain Hardjoprajitno. Similarly, field isolates of balcanica and tarassovi differed from their serovar reference strains, probably owing to a difference in epidemiological niche. Subdivision of these serovars into distinct subtypes as defined by BRENDA is therefore useful and justified. In contrast, analysis of serovars pomona, ballum and copenhageni shows that field and reference strains were identical, or differed only by a single band. It is suggested that BRENDA will overcome many of the problems associated with serological methods of identifying serovars and allow more precise definition of epidemiological relationships between strains and their hosts.

Base Sequence↗
PubMed1982

Colonization of the large bowel by Clostridium difficile in healthy infants: quantitative study.

Colonization of the large bowel of healthy infants by Clostridium difficile was studied. Feces were collected from five breast-fed aand five formula-fed infants throughout the first year of life, and levels of C. difficile were quantitated. Three breast-fed and five formula-fed infants were colonized for periods of between 8 and 42 weeks, and another infant harbored the organism only during week 1. Colonization of breast-fed infants commenced before or during weaning, with levels reaching 10(3) to 10(5) organisms per g of wet feces. Colonization of formula-fed infants commenced before solid foods were given, with levels of 10(3) to 10(7) organisms per g of wet feces. Isolates from eight of the babies were shown to produce cytotoxin in vitro. Single fecal specimens from 60 more children aged up to 4 years were also examined, and it was found that the carriage rate of C. difficile fell sharply after 1 year of age, although in the second year it was still higher than in adults. These findings are discussed in relation to the microbial ecology of the large bowel and the paradox that levels of C. difficile in the large bowel of healthy infants are similar to those causing pseudomembranous colitis in patients.

Bacterial Toxins↗
PubMed1982

A transport method for swab specimens submitted for aerobic and anaerobic bacteriology.

The need for separate swab transport methods for aerobes and anaerobes may result in inadequate transport of specimens for anaerobic bacteriology. Most microbiology laboratories in Australia rely on Stuart's transport medium to protect anaerobic bacteria. This paper presents a new, simple transport medium (Transport Deep) suitable for sue with aerobes and anaerobes. Comparative evaluations demonstrate that Transport Deep is as good as Stuart's medium for the maintenance of fastidious bacteria and is far superior for the protection of even extremely oxygen-sensitive anaerobes. This medium has been used successfully in a large Sydney hospital for more than a year. It is proposed that Transport Deep be used on a routine basis for all swab specimens.

Aerobiosis↗
PubMed1981

Changes in clinical presentation and management of malignant melanoma.

Records of 147 patients with primary cutaneous malignant melanoma treated at the Lahey Clinic from 1955--1979 were reviewed. Complete clinical follow-up data were obtained, and all pathologic material was reviewed. Proposed new risk categories based on a modification of the Clark and Breslow categorizations are outlined. The incidence of low-risk melanoma has dramatically increased (from 23--53%) and that of high-risk melanoma has decreased (from 34--10%) over the period of this study. Dermal punch biopsy gives accurate staging information and carries no increased risk of local recurrence, nodal metastases, or death from disease. Resection of a margin of clinically uninvolved skin measuring twice the diameter of the primary melanoma minimizes local recurrence (2.5% or less), does not adversely affect survival, and reduces the need for skin grafting. Arbitrary wide margins are not justified. Regional lymphadenectomy offers no improvement in survival in patients with low-risk and moderate-risk melanoma and can play only a minor role at most in improving survival for patients with high-risk melanoma.

Biopsy↗
PubMed1981

Case analysis as a teaching method in the paraclinical sciences.

A major problem in the teaching of the preclinical and paraclinical sciences to medical students is that courses are often taught in isolation from the clinical programme and students have difficulty relating the different types of learning experiences. This paper introduces case analysis as method designed to overcome this problem. The casebook method is popular with students and staff members and is a practical way of encouraging independent and motivated learning in the paraclinical sciences.

Education, Medical↗