Biomedical subjects
Publications and source records attributed to M M Ferguson.
A case of hemifacial atrophy in a 10-year-old boy is described. The presentation in this patient is unusual because the lesion is extremely localized, and the abnormalities of teeth in the affected region are more severe than previously recorded. Alternative diagnoses are considered, and the results of a computed tomographic scan with three-dimensional reformatting are presented.
The term ogee is proposed to describe dome or onion-shaped incisor roots as presented in a family study. A case of ogee permanent upper incisor teeth associated with microdontia, oligodontia, and tooth mobility is described. Forty-seven members of the proband's family were examined. The dental abnormalities were found to be of an autosomal dominant pattern of inheritance.
The possibility of whether the association between enzyme heterozygosity and body size (fork length) is consistent among rainbow trout (Oncorhynchus mykiss) with different degrees of relationship and is affected by fish age was determined. Six-month-old full-sibs and progeny groups from five and 13 parents of each sex do not show the positive associations between multilocus heterozygosity and fork length which are detectable in larger pooled gamete matings (25 females x 25 males). Moreover, the relationship between heterozygosity at single loci and fork length is inconsistent among families. These data suggest that chromosomal segments, marked by the enzyme loci, are responsible for the phenotypic effects (associative overdominance). Fish age affects both the strength and direction of the association between multilocus heterozygosity and fork length; the association is positive in 6-month-old rainbow trout but is weaker, negative, or differs between the sexes in fish at 1 year. Moreover, the strength of the relationship changes over time in repeated measurements on the same fish. A decline in growth of larger and more heterozygous fish, because of precocial sexual maturation, may partially explain the changing relationship between multilocus heterozygosity and fork length. Sexually mature males are significantly more heterozygous than immature males and show significantly reduced recent growth rates as measured by white muscle RNA concentration. However, females, who rarely mature at 1 year, show significantly higher recent growth rates. Thus, heterozygosity is differentially associated with the allocation of energy resources into somatic and reproductive tissue in male and female rainbow trout.
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A patient with a history of a burning tongue together with discomfort of the labial and buccal mucosae was given an elimination diet and skin patch tests to determine the allergen in her diet. The patient was identified as being intolerant of an aqueous peanut extract. Three allergens in peanut butter were identified, the one with greatest reactivity being a heat-stable, water-soluble, nonglycosylated protein with a molecular weight in excess of 10 kD. Modification of her diet has resulted in resolution of the oral problem.
Orofacial pain rarely arises from a distant site. It is unusual for orofacial pain to be associated with wasting of the facial musculature and diminished sensation. This case report describes a patient who presented with temporomandibular joint pain dysfunction syndrome which was initially successfully managed with splint therapy. She re-presented later with unilateral wasting of the muscles of mastication, facial pain and diminished sensation ipsilaterally. An intracranial meningioma was diagnosed following an extensive series of investigations.
Cryosurgery is an established technique for the removal of a range of mucosal lesions. As the portable carbon dioxide laser may provide an alternative form of treatment, the effectiveness of and the healing response following use of the 2 techniques was compared by producing lesions on the lateral border of sheep tongues. Cryosurgery produced more extensive lesions with a marked inflammatory reaction but no differences in the time course of healing were evident. Laser surgery was as effective as cryosurgery in the removal of superficial tissues but caused less swelling and, therefore, may be advantageous in some clinical situations.
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Exposure factors and screen-film combinations providing optimal quality are identified for transcranial and transpharyngeal temporomandibular joint views, using conventional intra-oral radiographic equipment without grids. Standardized transcranial and transpharyngeal views, using a fixed whole cadaver head, were performed. Ten readily available screen-film combinations, ranging in nominal speed 20-600, were exposed over 40-100 kV. Films were blindly and independently order ranked by three observers on the basis of sharpness and contrast of cortical outline, trabecular detail, and visualization of adjacent bony structures. Preferred screen-film combinations as a function of kV, preferred kV levels for each screen-film combination, and overall ranking irrespective of kV or screen-film combination, were established. Accepting the use of the lowest radiation dose possible for diagnostically useful radiographs but imposing arbitrarily an upper limit of 20 mGy, it was found that exposures between 50 kV and 70 kV gave the optimal result for both techniques. The amount of scattered radiation in the emergent beam differs greatly between the two techniques. The most favoured combinations for the transpharyngeal technique used screens of fine resolution. Min-r/ortho M screen and film with nominal speed 40 at 60 kV gave 8.0 mGy skin dosage at 0.8 seconds exposure; the same combination at 50 kV was the most favoured, but with skin dosage calculated at 16.7 mGy for 3.0 seconds exposure. For the transcranial technique, medium speed screens providing better differentiation of scattered radiation beams and increased speeds were preferred. Most favoured for image quality was the Lanex Fine/T-Mat G combination at 60 kV giving 17.5 mGy skin radiation dose at 1.75 seconds exposure.(ABSTRACT TRUNCATED AT 250 WORDS)
In previous experiments, the sucrose substitute Lycasin has been shown to possess low acidogenic potential. Intra-oral cariogenicity tests were carried out in humans to explore the enamel softening effects of Lycasin, using sucrose and saline as controls. The results confirmed that Lycasin would be preferred to sucrose as a sweetener for confections and medicines, although some softening of enamel by Lycasin was evident when compared to the saline controls. The magnitude of this enamel change was small and of doubtful clinical significance.
A technique is described for biopsy of the parotid salivary gland under local anaesthesia, which has been undertaken for a series of 59 patients who presented with suspected inflammatory exocrinopathy. The procedure is reliable and is associated with negligible postoperative discomfort. The advantages of the technique suggest that parotid gland biopsy is an acceptable alternative to conventional lower lip biopsy of minor salivary glands in the investigation of xerostomia.
The relationship between heterozygosity at nine polymorphic enzyme loci and disease resistance was examined in 373 individually identified rainbow trout (Oncorhynchus mykiss) from 12 full-sib families and a pooled gamete cross. These fish were challenged with bacterial gill disease, a potentially lethal epizootic in freshwater fishes. The 213 surviving fish had significantly greater numbers of heterozygous loci per fish and were significantly larger than the 160 individuals that died. Survivors, on average, had higher heterozygosity at six out of nine loci than non-survivors. The differences were significant at three of these loci. These findings suggest that more heterozygous rainbow trout have superior disease resistance than less heterozygous fish.
Amalgam restorations have been implicated both in contact sensitivity reactions and in lichenoid reactions. This appears to be related principally to the mercury content, although other metals cannot be discounted. The cases of two patients are reported who showed features of lichenoid reactions of the oral mucosa, in addition to features of a contact hypersensitivity to mercury. The mucosal lesions resolved following replacement of the amalgams with non-metallic restorations. Consideration is given to the selection of materials and procedures currently available for treatment of these patients. This paper supports the view that sensitivity to heavy metals must be considered as a possible cause of erythematous and lichenoid reactions of the oral mucosa.
This study investigates the production of bacteraemia in dental prophylaxis by use of a commercially available air polishing device. Prophylaxis by means of the conventional rubber cup and paste method was used as a control. The study showed that air polishing can result in loss of epithelium at the gingival margin. The likelihood of a bacteraemia resulting from air polishing, in the absence of gingivitis, was less than in the group undergoing conventional prophylaxis. Although a higher number of bacteraemias was seen in the control group, the difference between the two groups was not statistically significant. Results indicate that patients who are at risk continue to require antibiotic cover.
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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.
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.
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