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Biomedical subjects

D H Lloyd

Publications and source records attributed to D H Lloyd.

At least 91 records · Page 5Linked to original sources
PubMed1984

Evaluation of a cup scrub technique for quantification of the microbial flora on bovine skin.

A cup-scrub technique devised for sampling the human skin surface microflora was evaluated in cattle. Scrub samples from bovine skin contained clumps of squama and bacterial microcolonies which were progressively broken down by shaking. This was accelerated in the presence of ballotini beads but aggregations of bacteria were still present after prolonged agitation. Vigorous shaking, particularly with beads, decreased the viability of the bacteria and optimum viable counts were obtained after manual shaking for half a minute. Immersion in buffered detergent, wash and diluting fluids for up to 2 h promoted release of bacteria from microcolonies but decreased the viability of aerobic and anaerobic pleomorphic rods and a Bacillus strain. There was no significant effect on strains of Micrococcaceae. Prolonged exposure of bacteria from scrub samples to these fluids can thus lead to both quantitative and qualitative alterations in the counts obtained, although these effects may be masked by the continuing release of bacteria from microcolonies. The cup-scrub technique provides a convenient means of quantifying changes in the bovine skin microflora but results obtained from different studies should only be compared if closely similar techniques are used.

Animals↗
PubMed1984

Computerized bibliographic information service in a family practice clinic.

Access to current medical information is important for good-quality patient care. Computerized bibliographic information services (CBIS) have been evaluated in a family practice clinic as an aid to clinical decision making. Results suggest that CBIS is a relatively inexpensive, fast, easily accessible tool for clinicians, medical educators, and researchers.

Family Practice↗
PubMed1983

Location of immunoglobulins and complement (C3) at the surface and within the skin of dogs.

The serum proteins present at the skin surface in dogs were found to include the immunoglobulins (Ig) G, M and A, complement (C3) and albumin. Within the skin IgG and IgM were consistently found in the interstitial tissue throughout the dermis and were commonly present in the dermal blood vessels and hair papillae. IgA was undetectable or present in small amounts in the dermis in most of the 16 samples examined. It was found in the sweat glands, both in the lumen and the fundic epithelium, in some skin samples. C3 was demonstrated in the dermis and in the inter-cellular spaces of the stratum corneum. Elution of fresh skin specimens with phosphate buffered saline removed the majority of interstitial immunoglobulin and C3 from the dermis and some of the IgA from the sweat glands. IgM could still be demonstrated in the region of the epidermal basement membrane and C3 was not eluted from the stratum corneum. Removal of interstitial IgG and IgM facilitated the identification of immunoglobulin-bearing cells in the dermis. The distribution of IgG and IgM in dog skin is similar to that found in ruminants. Demonstration of IgA in the canine sweat gland fundus lends further support to the concept of IgA as a secretory immunoglobulin in the skin.

Albumins↗
PubMed1982

Effects of certain hallucinogenic amphetamine analogues on the release of [3H]serotonin from rat brain synaptosomes.

The enantiomers of 3,4-(methylenedioxy)amphetamine (MDA), p-methoxyamphetamine (PMA), and N-Me-MDA (MDMA), along with their alpha, alpha-dimethylated derivatives, were evaluated for an effect on the release of [3H]serotonin from rat whole brain synaptosomes. The amphetamine isomers were all potent in inducing the release of [3H]serotonin at bath concentrations of 1 and 10 micrometers but were inactive at 0.1 micrometers. No significant difference in isomer potency was observed at the 10 micrometers concentration. However, at 1 micrometer the (+) isomer of MDMA was more effective in inducing release than was the (-) isomer. Since it is the (+) isomer which is clinically active, this result suggests that transmitter release may play a role in the biological activity of MDMA. By contrast, the alpha, alpha-dimethyl compounds were not effective in releasing serotonin, even at the highest bath concentration.

Amphetamines↗
PubMed1982

Epidermal structure and surface topography of canine skin.

The stratum corneum of canine skin when measured in cryostat sections was found to have a mean thickness of 47.5 cell layers and measured 13.3 micrometers. The living epidermis was composed of three to six cell layers and measured 10.1 micrometers. Stratum corneum thickness was similar on the back and abdomen but was greater in the inguinal fold. Lipid was found in the distal intercellular spaces of the corneum to a mean depth of 34 cell layers. The surface topography of freeze dried canine skin was examined by scanning electron microscopy. The interfollicular stratum corneum was generally covered by a thin homogeneous film but in some areas hexagonal squames surrounded by amorphous globular material, which appeared to be oozing onto the surface, could be found. This material, which was also found sealing the bases of hair follicles and matting together the emerging hairs, appeared to be sebaceous lipid.

Abdomen↗
PubMed1981

Measurement of antibody to Dermatophilus congolensis in sera from cattle in the west of Scotland by enzyme-linked immunosorbent assay.

Serum antibody titres to Dermatophilus congolensis demonstrated by an enzyme-linked immunosorbent assay (ELISA) in young steers and in adult cows from an Ayrshire herd showed a bimodal distribution and provided evidence of subclinical infection. Very high titres detected in sera from crossbred Galloway steers were indicative of recent or existing infection which may have been masked by concurrent ringworm. The ELISA is a sensitive and technically simple method which enables sera to be screened for evidence of infection by D congolensis which may otherwise pass unrecognised. Such infections may be of importance not only in the epidemiology of the disease in farm animals but also as a potential source of infection for man and his domestic pets.

Actinomycetales↗
PubMed1979

Structure of the epidermis in Ayrshire bullocks.

The living epidermis and stratum corneum of cattle, when measured on cryostat sections, were both found to be approximately 30 micrometer thick. However, the corneum contained about 30 cell layers, whereas the living epidermis was composed of only four. Histological processing involving fixation, dehydration and paraffin embedding, resulted in the loss of half of the stratum corneum and proved to be unsuitable for study of this layer. Lipid derived mainly from the sebaceous gland was present between the squames in the outer two thirds of the corneum probably in the form of an emulsion with sweat.

Animals↗
PubMed1979

Structure of the sheep epidermis.

The stratum corneum measured on fresh frozen sections was found to be considerably thicker than previously reported. It was uniformly permeated with sebum, which also formed an intact film over the skin surface and it could readily be divided into two zones. The living epidermis was approximately half as thick as the stratum corneum.

Animals↗
PubMed1979

The effects of some surface sampling procedures on the stratum corneum of bovine skin.

Clipping and shaving remove cell and lipid layers from the stratum corneum and also modify the effects of subsequent lipid collection and microbiological sampling techniques. The damage to the epidermis caused by solvents indicates that further evaluation of some sebum collection procedures and of the effects of dips and dressings applied to the skin is required.

Animals↗
PubMed1979

Location of immunoglobulins in the skin of cattle and sheep.

The pattern of distribution of immunoglobulins (Ig) found within the skin of cattle and sheep was the same in both species. IgA was detected mainly in the sweat gland duct and in the intercellular spaces of the living epidermis. IgG was also located at the latter site but was found in greater amounts throughout the dermis and in the endothelium of the blood vessels. IgM was primarily located at the basement membrane of the epithelial structures, in the hair papilla and in the walls of the blood vessels. Lower concentrations of IgM were also detected in the upper dermis.

Animals↗