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Biomedical subjects

J W Rippin

Publications and source records attributed to J W Rippin.

34 records · Page 2Linked to original sources
PubMed1989

Pulpal response to an anhydrous glass ionomer luting cement.

This investigation was designed to study the pulpal responses to Aquacem, an anhydrous glass ionomer luting cement, and to compare the results with those previously obtained for a conventional glass ionomer luting cement, Chembond. The study was carried out according to the BSI (1980) recommendations for testing restorative materials in vivo. Aquacem caused more pulpal inflammation than the control material, Kalzinol, though by an indirect mechanism. The statistical model demonstrated a significant association between bacterial presence within the experimental cavity and pulpal inflammation. The type of restorative material has no direct association with the degree of inflammation, but the model suggests that it exerts an indirect influence via its antibacterial properties and hence its influence on microbial microleakage.

Animals↗
PubMed1989

Analysis of cell cycle subpopulations from cytometric data.

As a result of experimental error, measurements of the DNA content of cells from proliferating populations give rise to histograms in which the G1-phase, S-phase and G2-phase distributions overlap. A new method for distinguishing these subpopulations is proposed, based on a model in which the S-phase subpopulation is made up of a number of uniformly overlapping log-normal curves, whose composite has a rectangular central part and sloping ends. The ratio between certain parameters of the slopes and the height of the rectangle is shown to be closely related to the degree of overlap of the constituents by a defined cubic polynomial. It is then possible to calculate the numbers of cells in each of the three phases of the cell cycle, even when only a few hundred cells have been measured.

Animals↗
PubMed1988

The post-operative maxillary cyst. Experience with 23 cases.

23 cases, diagnosed as post-operative maxillary cyst, from outside Japan are described. Clinical, radiographic and histopathological features are not dissimilar to those cases reported from Japan, and various parameters have been found to be helpful in diagnosis. This lesion is more common outside Japan than previously suggested, and this is probably largely due to faulty diagnosis.

Adult↗
PubMed1988

Medical science and the patient.

Classification is necessary to most forms of thought, and the scientific method requires particular refinement of this process in order to formulate its laws. But there is nothing fundamental about any classification; its categories are chosen for a particular purpose only, and often at least some of the subjects do not fall readily into any class. Furthermore, since only few of an individual's characteristics are used as classifying attributes, individuals themselves become submerged in the class, and their individuality lost in the scientific laws that arise therefrom. Desiderata of science and uniqueness are therefore opposed--and they are irreconcilable because absolute knowledge is either non-existent or unattainable. Thus, the decision as to whether an individual patient is healthy or diseased must be made on the basis of diagnostic laws which, as far as the individual is concerned, are inaccurate and may turn out to be spurious or even meaningless. These laws are therefore only guide-lines which must be 're-individuated' in clinical practice. In essence, the individual's health depends on the individual's biology.

Classification↗
PubMed1987

The odontogenic keratocyst and its occurrence in the nevoid basal cell carcinoma syndrome.

There are histologic differences between odontogenic keratocysts occurring in the basal cell carcinoma syndrome (NBCCS) and as single lesions in otherwise healthy persons. This study identifies certain differences in age, gender, and site between the two groups. The age at removal of the first keratocyst is significantly lower in the syndrome group. On more thorough examination, patients with multiple keratocysts (excluding recurrences) are found to have other features of NBCCS. The term multiple cysts refers to the lifetime history of the patient and does not necessarily imply that more than one cyst is present at any one time.

Adolescent↗
PubMed1987

A comparative histological study of odontogenic keratocysts in basal cell naevus syndrome and control patients.

164 odontogenic keratocysts from 60 patients with the basal cell naevus syndrome were compared with a similar number of single keratocysts matched for age and site. Significant differences between the two groups were found in the numbers of satellite cysts, solid islands of epithelial proliferation and odontogenic rests within the capsule, and in the numbers of mitotic figures in the epithelium lining the main cavity. An index of activity derived from these parameters suggests a greater growth potential in syndrome cysts; in addition, the patterns of association of the features support the theory that the odontogenic rests give rise to satellite cysts.

Adolescent↗
PubMed1987

A comparative study of the clinical and histological features of recurrent and non-recurrent odontogenic keratocysts.

The clinical features of 44 recurrent odontogenic keratocysts were compared with those of 228 single non-recurrent keratocysts which had been followed for 5 or more years. Histological comparisons were made with 44 non-recurrent cysts matched for age, sex and site. There were no significant differences in the age, sex and site between patients with recurrent and non-recurrent cysts. There were no significant histological differences except for a greater amount of inflammation in the non-recurrent cysts. It is suggested that operative factors have a major influence on the likelihood of recurrence.

Adolescent↗
PubMed1987

The basal cell naevus syndrome.

The basal cell naevus syndrome, classically described as a triad of multiple basal cell carcinomas, odontogenic keratocysts of the jaws and skeletal anomalies, is well known by oral and plastic surgeons and dermatologists. This paper describes the clinical features in a series of 60 patients, and highlights some problems of diagnosis and management.

Adolescent↗
PubMed1984

DNA content and proliferation of rat thymocytes.

Scanning microdensitometric analysis of Feulgen stained thymocytes from rats aged 1 to 71 days revealed the presence of a number of waves of cell proliferation which may correlate with the development of functionally distinct T-cell subpopulations. In addition, considerable numbers of hypodiploid cells were seen. It is tentatively suggested that thymocyte development involves reduction division and replication of the haploid chromosomes so produced, prior to cell proliferation.

Animals↗
PubMed1984

Autofluorescent granular cells in odontogenic cysts.

Three odontogenic cysts, two of dentigerous and one of dental type, are reported in which large numbers of cells containing autofluorescent granules were present, in both the capsule and cyst lining. Histochemical and electron microscopical studies suggest that the granules are composed of lipofuscin. Examination of 30 examples each of dental cysts, dentigerous cysts and odontogenic keratocysts indicated that the prevalence of occasional cells of similar appearance was about 40%, 50% and 17% respectively. The pathogenesis of these cells is discussed.

Adult↗
PubMed1977

Autofluorescent granular cells in oral mucosal hyperplasias.

Four hyperplastic lesions of the hard palate are described. They were characterized by the presence of an atrophic surface epithelium, an oedematous matrix and the presence of large numbers of autofluorescent granular cells. In addition there were numerous mast cells. Histochemical and electronmicroscopical studies suggest that the granules are composed of lipofuscin. The pathogenesis of these lesions is discussed.

Aged↗