Prophylactic extraction of lower third molars: setting the record straight.
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Child↗
Biomedical subjects
M E Richardson
Publications and source records attributed to M E Richardson.
The layman's view of orthodontics: a literary review.
It is probably true to say that the masticatory apparatus attracts proportionally greater attention than any other part of the body. Evidence that this is so is provided, not only by the degree of specialisation within the dental profession, but by the frequency with which references to teeth and dentistry crop up in literature. Generations of biographers, novelists, poets, playwrights and essayists have written about their dental experiences and included the dentition in describing the facial appearance of characters, factual and fictional. The literary extracts in this article, culled from an extensive collection, refer to orthodontics. They provide a fascinating insight into the patient's perspective on that speciality and make entertaining reading.
Attitude to Health↗
Lower arch crowding in the third decade.
Lower arch crowding and dimensions were measured on study models of 46 untreated subjects, 20 male and 26 female, at age 18 years (T1), 21 years (T2), and 28 years (T3), and the changes during the observation periods calculated. Only very small changes, few of them detectable clinically, were found. The findings are discussed in relation to the changes reported in untreated subjects in other age groups and in orthodontically-treated subjects after retention.
Adolescent↗
Tumor cell heterogeneity: impact on mechanisms of therapeutic drug resistance.
PURPOSE: The aim of these studies was to determine whether chemotherapy-resistant tumor cell sublines derived from a single starting cell population with identical treatment protocols, have the same mechanism of resistance. METHODS AND MATERIALS: Twelve cyclophosphamide-resistant sublines were derived from KHT-iv murine sarcoma cells by repeated exposures to 2, 4, or 8 microg/ml doses of 4-hydroperoxycyclophosphamide (4-OOHCP). To investigate possible mechanisms of resistance, glutathione (GSH) levels, glutathione S-transferase (GST) activity, and aldehyde dehydrogenase (ALDH) activity were determined. In addition, studies with the GSH depletor buthionine sulfoximine (BSO) and the ALDH inhibitor diethylamino-benzaldehyde (DEAB) were undertaken. RESULTS: Resistant factors to 4-OOHCP, assessed at 10% clonogenic cell survival, ranged from 1.5-7.0 for the various cell lines. Crossresistance to melphalan and adriamycin also were commonly observed. Increased GSH levels, GST activity and ALDH activity were detected in the sublines but not all exhibited the same pattern of biochemical alterations. The response to GSH and ALDH inhibitors also varied among the sublines; the resistance being reversible in some cell lines but not others. CONCLUSION: The present results indicate that when resistant sublines are derived simultaneously from the same starting cell population, the observed mechanisms of resistance may not be the same in each of the variants. These findings support the hypothesis that preexisting cellular heterogeneity may affect mechanisms of acquired resistance.
Aldehyde Dehydrogenase↗
Late lower arch crowding in relation to soft tissue maturation.
Changes in lower arch space condition and incisor inclinations were measured in relation to changes in the cross-sectional area and separation of the lips in habitual posture in 23 boys and 23 girls between the ages of 12.5 and 15.5 years. Correlation analysis revealed no direct relationship between the increase in lower arch crowding and the changes in lip size and position. In girls, the increase in lower arch crowding was associated to some extent with retroclination of the upper incisors and an increase in the interincisal angle. A very tenuous relationship was found between changes in the upper lip size and position and changes in incisor angulation.
Adolescent↗
Fever, cardiac failure and arteritis in a child with rheumatic carditis.
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Angiography↗
Musculoskeletal examination needs to be a matter of habit.
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Humans↗
Late lower arch crowding in relation to the direction of eruption.
The change in lower arch crowding 3-4 years after second permanent molar eruption was examined in 85 subjects, in relation to the angulation and change in angulation of molars and incisors relative to the mandibular plane using correlation and multiple regression analyses. Crowding increased significantly during the observation periods. Changes in molar and incisor angulation in both mesial and distal directions were observed. The increase in crowding was not related to molar or incisor angulation at 12 years. Some association between increase in crowding, reduction in arch depth and retroclination of incisors was found.
Adolescent↗
Late lower arch crowding in relation to skeletal and dental morphology and growth changes.
Skeletal and dental morphology, and related growth changes during a 3-year period following second permanent molar eruption, were compared in a group of 21 subjects who had no increase in lower arch crowding, with another group of 21 subjects whose lower arch crowding had increased by 1.0 mm or more during the same period. The crowding group showed a significantly greater increase in M3 space, forward movement of the second permanent molar and increase in the inter-incisal angle than the non-crowding group. None of the other parameters examined differed significantly.
Adolescent↗
Rooming-in: an alternative to involuntary detention.
OBJECTIVE: To provide, via 'rooming-in', a local, less coercive and less frightening alternative to involuntary detention. Rooming in is the voluntary participation of so-called 'confidants', who may be chosen family members or trusted friends, in the management of acute, severe psychiatric disturbance by their providing a 24 hour vigil with the patient in a single, safe hospital room. METHOD: There were 73 admissions to the rooming-in program at the Manning Base Hospital, Taree, New South Wales (NSW), Australia between 5 August 1986 and 21 September 1992. During the same period 78 patients were remitted from the hospital on an involuntary basis to urban detention centres: 'scheduled' under the NSW Mental Health Act. Demographic and diagnostic characteristics of the two populations, both of whom met identical criteria for involuntary detention, are compared in this retrospective, case report study. These two groups constituted only 6% of total psychiatric consults carried out at the hospital over the same 6 year period and those roomed-in represented only 12% of the psychiatric admissions. A quality assurance study evaluated the acceptability of the program. RESULTS: The scheduled patients were more likely to be single, of no fixed abode and without a local family. They were more likely to have a schizophrenic disorder, compounded by polysubstance abuse, than a mood disorder. The average inpatient stay for those roomed-in was 10 days. Seventy per cent of confidants were required for 4 days or less. The rooming-in program was valued highly by nursing staff, patients and their families. CONCLUSION: A search of the world literature would suggest that rooming-in, as a model of care, is unique, at least in the developed world. It allows some seriously disturbed patients to be provided with a local and less restrictive general hospital alternative.
Adolescent↗
Orthodontic implications of lower third molar development.
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Adolescent↗
Mesial migration of lower molars in relation to facial growth and eruption.
Mesial migration of teeth in the buccal segments is a well recognised phenomenon in the human dentition. Its aetiology is not fully understood. It has been suggested that it is, to some extent, dependent on growth changes in the lower face. The purpose of this investigation was to examine mesial movement of first molars in the intact lower arch in relation to the amount and direction of facial growth and eruption of teeth. Mesial migration of lower first molars between 13 and 18 years was measured on 60 degrees cephalograms of 22 males and 29 females with intact lower arches. Correlation analyses were used to examine the relation between mesial migration and tooth eruption, growth changes in mandibular length and anterior face height and direction of growth. There was, on average, forward movement of first molars of 2.0-3.0 mm and eruption of 2.0-4.0 mm. No relation was found between forward movement of first molars and their eruption or the amount and direction of facial growth.
Adolescent↗
Second permanent molar extraction and late lower arch crowding: a ten-year longitudinal study.
The purpose of this investigation was to examine lower arch alignment in the long term following treatment by second molar extraction. Thirty subjects, treated by extraction of four second permanent molars at an average age of 13.9 years, were examined five and ten years after extractions. None had any mechanical treatment in the lower arch. Twenty had some simple upper arch treatment, including, in five cases, extraction of first premolars. The changes in lower arch alignment were measured on study models. There was a small average decrease in lower arch crowding in the first five years following extraction, and little or no change in alignment in the next five years.
Adolescent↗
DNA damage in cyclophosphamide-resistant tumor cells: the role of glutathione.
The relationship between DNA damage removal and cellular sensitivity to the alkylating agent cyclophosphamide (CP), currently one of the most effective drugs in the treatment of human tumors, has not been well established. In the present study, we have analyzed drug-induced DNA cross-link persistence in the CP-resistant subline KHT-rep/iv and its sensitive counterpart KHT-iv. The alkaline elution technique was used to detect both DNA-DNA and DNA-protein cross-links formed following exposure to clinically achievable CP concentrations. In addition, the role of glutathione (GSH) in the cross-link persistence was analyzed. The KHT-rep/iv cell line was chosen for study because compared to the parent KHT-iv line, this cell line demonstrates 2-3-fold increased GSH levels, and resistance to CP is known to be mediated by thiols. Following exposure to 4-hydroperoxy-cyclophosphamide (4-OOHCP), an active form of CP, the KHT-rep/iv cells exhibited fewer total cross-links and a shift in the time of maximal cross-link formation (6.2 at 2 h versus 2.9 at 4 h for the parent and resistant lines, respectively). When the GSH content of the resistant cells was reduced to equal that of the parent cell line prior to the alkaline elution assay, both the total number and time course of development of cross-links were similar between the two lines. Also, when the cells were exposed to mechlorethamine, an alkylating agent which forms cross-links at a much faster rate than 4-OOHCP, the time course of cross-link formation after mechlorethamine exposure was similar between the two sublines, with maximal cross-link formation occurring after a 1-h incubation. The present findings suggest that (a) the increased GSH levels in KHT-rcp/iv cells may be responsible for the delay in maximal cross-link development after treatment with 4-OOHCP, possibly by binding with the monoadduct produced by the drug; and (b) the faster reaction rate of mechlorethamine cross-link formation may prevent the tripeptide from binding to the monoadduct. These results are consistent with the hypothesis that GSH may "quench" the formation of cross-links following 4-OOHCP exposure.
Cell Division↗
Late lower arch crowding: the role of the transverse dimension.
Fifty subjects who were followed longitudinally between 13 and 18 years showed an average increase in lower arch crowding of 2.36 mm. This increase in crowding was examined in relation to tooth width, arch width and jaw width, actual and relative, and to changes in these dimensions with correlation and multiple regression analyses. No relationship was found between width dimensions and late crowding in the lower arch.
Adolescent↗
A preliminary report on lower arch crowding in the mature adult.
Changes in lower arch crowding were measured on models of 16 subjects between the ages of 18 and 50 years. Changes in position of various cephalometric points relative to the skull base were measured on 90-degree left lateral cephalograms. Some increase in lower arch crowding was found in 80 per cent of subjects. With one exception, all subjects showed changes in size and orientation of the jaws relative to the skull base varying in amount and direction. Possible causes of increased lower arch crowding in the mature adult are discussed.
Adolescent↗
Expression of epidermal growth factor (EGF) and the EGF receptor in the porcine oviduct.
The production, secretion, and localization of epidermal growth factor (EGF) and the distribution of the EGF receptor (EGF-R) were examined in the isthmus (I) and ampulla (A) of the oviducts from cyclic (C) and early-pregnant (P) gilts. Sexually mature gilts (n = 20) were divided equally into two groups: C and P. P gilts were bred twice (at 0 and 24 h), and all gilts were killed 48 h after onset of estrus. After removal of reproductive tracts, oviducts were isolated, flushed, opened longitudinally, divided by anatomical region, cut into 1-3-mm3 pieces, and placed in Dulbecco's modified Eagle's Essential medium (DMEM: F-12 + ITS [insulin, 5 micrograms/ml; transferrin, 5 micrograms/ml; and selenious acid, 5 ng/ml] + antibiotic). Half the tissue and medium were immediately homogenized and centrifuged, and the supernatant was removed. The remaining tissue was cultured in the medium for 24 h at 37 degrees C and 5% CO2, then prepared similarly for analysis. EGF was measured in the supernatant by a heterologous RIA. Concentration of EGF was expressed as nanogram/milliliter of EGF per milligram of protein in wet tissue. EGF concentrations were present in both regions of the oviducts of C and P gilts. It was greater in I than in A tissues for both C (I = 16.21 ng/ml vs. A = 13.91 ng/ml; p < 0.05) and P gilts (I = 14.27 ng/ml vs. A = 12.53 ng/ml; p < 0.10). Higher concentrations of EGF were found in I tissue of C gilts than in P gilts (C = 16.21 ng/ml vs. P = 14.27 ng/ml; p < 0.05). The media assayed from cultured explants of I and A sections from C and P gilts gave results that were highly correlated with those of immediately prepared tissue sections. Localization of EGF in frozen oviductal tissue sections was demonstrated by immunohistochemistry. The primary site of EGF immunostaining occurred in the epithelial cells (with highest intensity at the apical border) of both C and P gilts. A and I tissue sections from C gilts showed localization of EGF immunostaining mainly in epithelial cells and lamina propria cells, while those from P gilts stained less intensely. The presence of EGF-R was shown by incubating tissue imprints and frozen sections with EGF-erythrosin isothiocyanate, which revealed that EGF-R were distributed mainly on the membranes of epithelial cells. The study indicates that EGF and EGF-R are present in oviductal epithelial cells in both C and P gilts, with the highest concentration of EGF in C gilts.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Developmental changes in alignment of the lower labial segment.
The purpose of this study was to examine changes in lower incisor alignment at various developmental stages, from the time of eruption to the established permanent dentition and to try to predict the degree of crowding in the permanent dentition from that observed at earlier developmental stages. Forty-eight subjects (20 male, 28 female) with intact mandibular arches were selected from the Belfast growth study records. The lower incisor space condition was measured at each of four developmental stages: (1) initial eruption of the lower permanent incisors; (2) initial eruption of the permanent canines; (3) initial eruption of the second molars; (4) 3 years after eruption of the second molars. Differences in lower incisor space condition between each developmental stage were investigated and correlation analyses between the space conditions at each stage were carried out. On average, crowding of the lower incisors decreased to a statistically significant degree (- 0.9 mm) between stages 1 and 2, and increased between stages 3 and 4 (0.4 mm). Significant correlation coefficients between space condition at each developmental stage were found, but were considered unreliable as predictors of lower incisor crowding in the mature dentition.
Child↗