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Biomedical subjects

M M Ferguson

Publications and source records attributed to M M Ferguson.

At least 73 records · Page 4Linked to original sources
PubMed1989

Histological evaluation of the effect of a miniature carbon dioxide laser on oral mucosa.

Carbon dioxide lasers emit infra-red radiation at a wavelength of 10600 nm, making them suitable for tissue vaporisation, incision and vessel coagulation. A miniature CO2 laser (length 24 cm), with an output of 4 Watts focused on to a spot of 0.2 mm diameter at a distance of 2.5 mm from the nozzle tip, has been developed. This hand-held, water-cooled device operates off a 12 V D.C. source and provides good access to most areas of the mouth. In order to evaluate the use of the miniature laser, a series of lesions were produced on the lateral margins of sheep's tongues, and histological examination of tissues carried out immediately after treatment and at 1 h; 1, 2, 4, 7, 14, 21, and 28 day intervals. Wounds showed clean cut margins with even removal of epithelium and superficial connective tissue. Damage appeared to be restricted to a 100 microns deep zone in the lamina propria. Epithelial regeneration had commenced at between 2 and 4 days, and re-covered the surface by 14 days. A residue of chronic inflammatory cells was present within the stroma at 21 days, but this had resolved by 28 days. The miniature carbon dioxide laser is effective in vaporising oral mucosa and also achieving haemostasis by vessel coagulation; its manoeuvrability and relatively low cost warrant further clinical evaluation for the treatment of mucosal lesions, such as leukoplakia.

Animals↗
PubMed1989

Oral hairy leukoplakia-like lesions in an HIV-negative male: a case report.

Oral hairy leukoplakia is generally found only in HIV-seropositive individuals or in those who are at risk of developing this infection; its occurrence is accepted to be a reliable predictor for the development of AIDS in those patients who are not already suffering from this disease. This report describes an 18-year-old male who was proven to be HIV-seronegative, was not in any of the at-risk groups associated with this infection, but who had the typical features of oral hairy leukoplakia, clinically and histologically. In such individuals these lesions should be described as hairy leukoplakia-like lesions.

Adolescent↗
PubMed1989

Reduction of UV-induced erythema in normal subjects by applying methimazole.

Since free radicals are probably involved in the induction of erythema following ultraviolet (UV) irradiation, a study was conducted to investigate the influence of a topical application of methimazole (a free radical scavenger), before and at different times up to 2 h, after exposure to UV radiation. Seven subjects took part and erythema was assessed 6 h after exposure by a quantitative reflectance technique. Erythema was reduced at the sites that received methimazole 15 min prior to exposure and, although the trend was towards a decrease in erythema at the sites where methimazole was applied after exposure, the mean differences in these cases were not significant. It is believed that methimazole may have a useful role in the reduction of erythema following UV irradiation.

Administration, Cutaneous↗
PubMed1989

Contact stomatitis caused by toothpaste.

A clear association between the use of cinnamaldehyde containing toothpaste and inflammation of the lips, labial mucosa, and gingivae is described in a 59-year-old man. The sensitivity reaction was verified by patch testing with cinnamaldehyde.

Acrolein↗
PubMed1988

Developmental rates of heterozygous and homozygous rainbow trout reared at three temperatures.

The hatching distributions of rainbow trout (Salmo gairdneri) with different genotypes at eight loci are compared in two experiments with the same strain. Embryos were incubated at temperatures colder (5 and 8 degrees C) and warmer (12 degrees C) than normally experienced by these fish (9.5 degrees C). At hatching, embryos were separated into five hatching groups representing the chronological order of hatching. There is no significant correlation between multilocus heterozygosity and hatching time at any temperature in either experiment. Fish in the middle of the hatching distribution had the highest average heterozygosity. In both experiments, heterozygotes at the majority of loci examined tended to hatch relatively later within the hatching distribution at 12 degrees C than at both 5 and 8 degrees C. Fish with different genotypes at Pgm2 and Ck1 showed significant differences in hatching time that were consistent between experiments. Ck1 heterozygotes hatched sooner than homozygotes at 8 degrees C but later at 12 degrees C. Pgm2 heterozygotes hatched later than homozygotes at all temperatures and significantly later in four of five cases. At the other loci examined, however, the relative hatching distributions of fish with particular genotypes were not significantly different or repeatable between experiments.

Animals↗
PubMed1988

Temperature-dependent genotypic selection and embryonic survival of rainbow trout.

The survival of rainbow trout (Salmo gairdneri) with different developmental rates and genotypes at eight polymorphic loci was compared in two experiments. The embryos were reared at temperatures colder (5 and 8 degrees C) and warmer (12 degrees C) than normally experienced by the strain (9.5 degrees C). Embryo survival in five different hatching groups (representing the sequential order of hatching) was compared at 8 and 12 degrees C. Embryos in the center of the hatching distribution (groups 2, 3, and 4) showed a greater survival to yolk sac resorption than those in the extremes (groups 1 and 5). These differences are significant in the embryos reared at 12 degrees C in both experiments. Embryo survival from hatching to yolk sac resorption was poorer at 12 compared to 8 degrees C. In the one experiment where it was examined, significantly fewer embryos hatched at 5 and 12 than at 8 degrees C. Significant deviations from genotypic expectations (based upon parental allele frequencies) were detected in the progeny (23 of 34 cases). In contrast, few deviations from Hardy-Weinberg expectations were detected (5 of 34 cases) when progeny allele frequencies are used. Few significant differences in genotype frequencies were detected among the progeny reared at the different temperatures. This suggests that nonequal contributions of parental gametes rather than differential selection of genotypes account for the deviations from expectations in the progeny.

Acclimatization↗
PubMed1988

Developmental rate and viability of rainbow trout with a null allele at a lactate dehydrogenase locus.

We show that a previously described isozyme polymorphism in rainbow trout (Salmo gairdneri) is the result of an enzymatically inactive (i.e., null) allele (n). Ldh3 null homozygotes (n/n) and heterozygotes (100/n) have reductions of about 20 and 12% in total lactate dehydrogenase (LDH) activity at hatching, respectively. As juveniles, (100/n) fish have reductions in LDH activity of 15, 37, and 21% in brain, heart, and white muscle, respectively. Embryos with different Ldh3 phenotypes from 11 families do not differ significantly in either survival or hatching time. However, a second measure of developmental rate, the amount of malate dehydrogenase (MDH) and phosphoglucomutase (PGM) activity in 33-day-old embryos, suggests that (100/n) embryos develop more slowly than (100/100) embryos. In three of four families examined, (100/n) embryos have significantly lower amounts of total MDH activity (8-10%). In one of these, (100/n) embryos also have significantly lower total PGM activity (15%). These data suggest that the reduction in total LDH activity is associated with small but detectable delays in developmental rate but nondetectable differences in survival to hatching.

Aging↗
PubMed1988

The effect of chlorhexidine and benzydamine mouthwashes on mucositis induced by therapeutic irradiation.

A variety of mouthwashes are frequently used in the management of irradiation-induced mucositis. Benzydamine has recently been introduced for alleviating this condition. Its efficacy as a mouthwash was compared with chlorhexidine in two groups of patients receiving radiotherapy for oral carcinoma. Mucositis and pain were recorded over a 6 week period and oral carriage of Candida species, coliforms and Staphylococcus aureus was assessed using an oral rinse technique. There was no significant difference in the mucositis scores, overall pain scores or the yeast and bacterial species isolated between the two treatment groups. However, 58% (7 out of 12) and 92% (12 out of 13) patients reported oral discomfort when rinsing the mouth with chlorhexidine and benzydamine, respectively. In both groups, the most common coliform isolated was Klebsiella pneumoniae and the carriage of yeasts was significantly greater than that of coliforms. These results indicate that, although the individual patient acceptance of chlorhexidine is better than benzydamine, there is little difference between the two mouthwashes both in controlling pain and mucositis or in the oral carriage of the micro-organisms studied.

Aged↗
PubMed1988

Co-oxidation of arachidonic acid and methimazole by prostaglandin endoperoxide synthetase.

The thiocarbamide methimazole stimulated O2 utilisation when added to reaction mixtures containing ram seminal vesicle microsomes (prostaglandin endoperoxide synthetase preparation) and arachidonic acid. This stimulation increased with increasing methimazole concentrations, as did the production of prostaglandin E. 2-[14C]Methimazole was co-oxidized to 1-methyl-2-[14C]imidazole.

Animals↗
PubMed1987

Oral lichenoid reactions related to mercury sensitivity.

Lichen planus is a common disorder of unknown aetiology. It has been proposed that in some cases it represents a form of allergic reaction to the metals contained in dental amalgam, particularly mercury. Twenty-nine consecutive dentate patients who had lichen planus of the oral mucosa were patch-tested to the range of metals contained in dental amalgam. Ten out of 29 (34%) showed an allergic reaction to mercury and all of these patients had amalgams greater than 5 years old. The amalgams were poorly contoured and had corroded, resulting in continued release of mercury ions. Six patients had their amalgams replaced with composite or glass ionomer materials resulting in resolution of ulcerated lesions. In a follow-up of 3-24 months, one patient had a recurrence of ulcerated areas and another, despite resolution of the oral lesions had persistent discomfort.

Adult↗
PubMed1987

Evoked taste thresholds in a normal population and the application of electrogustometry to trigeminal nerve disease.

No standardised method for taste threshold measurement is available and therefore comparison between clinical studies is difficult. An electrogustometer was evaluated in normal subjects. No sex difference in taste threshold was noted; however, there was a significant elevation in detection threshold with age and smoking. Electrogustometric values both in patients before and after surgery for trigeminal neuralgia and in patients with trigeminal sensory neuropathy were determined. Many patients with trigeminal nerve disorders had abnormal electrogustometric detection thresholds suggesting that there is possibly an accessory taste pathway through the trigeminal nerve, although in some individuals the site of lesion may be in the brain stem. Electrogustometry is a convenient method for clinically assessing taste.

Adolescent↗