Changes in blood coagulation during infusion of intralipid.
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Blood Coagulation↗
Biomedical subjects
D J Reid
Publications and source records attributed to D J Reid.
Changes in whole body venous tone in surgical patients.
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Abdomen↗
Histological reconstruction of dental development in four individuals from a medieval site in Picardie, France.
The majority of dental development studies in modern humans are based on radiographic analysis. In comparison, very few full histological studies have been carried out. In the present study, the onset of enamel formation and crown formation time have been established by histological analysis of the complete dentition in a medieval French individual. Crown formation times were established for the dentition of three further individuals. The number of cross-striations between adjacent striae of Retzius was measured and accentuated striae were used to construct a chart of the chronology of tooth development. Results on crown formation times in individual teeth when compared with previous histologic studies are slightly greater than values in a modern African male and near to or less than values in (M1) and (I) respectively in a modern population from Spitalfields, London. Histologically derived crown initiation times are earlier than those reported for radiographic studies. Values for crown formation times derived in general from radiographic studies are less than those of our study. Attention has recently been focused on the overlap of molar development as a key character for distinguishing between humans and great apes. In this study, there is an overlap in crown formation between M1 and M2 of 0.27 years and a temporal delay of 1.7 years between M2 crown completion and the initiation of the M3.
Adult↗
Radiographic and histological methodologies in estimating the chronology of crown development in modern humans and great apes: a review, with some applications for studies on juvenile hominids.
There has been a burgeoning of interest in the last decade on growth studies in hominids. These studies have relied heavily on dental development, and have compared juvenile hominids to modern human and ape standards, which are usually established using radiographic data. There has been considerable discussion on the most appropriate methods of deriving population standards from radiographs, but very little on the accuracy of the radiographic image itself. Previous histological and dissection studies have shown that age at onset of mineralization is overestimated, and age at crown completion is underestimated using radiographs. This study considers the process of X-ray absorbence by mineralized tissues and the formation of radiographic images of developing teeth. Following tooth initiation a critical mass of mineral is required for the tooth to register superimposed on the absorbence of alveolar crypt bone, which accounts for the late identification of tooth initiation. Determination of completion of crown growth depends upon the identification of the last formed enamel at the cervix. Recognition of this key stage is difficult as crown growth slows towards the cervix, and the last secreted enamel may take months to attain full mineralization levels due to the prolonged maturation process. Morphological and geometric factors have a significant influence on the imaging of the completed crown. The last formed enamel is located on the buccal face, where enamel thins progressively to nothing. X-ray absorption by enamel at the cervix becomes insignificant, and may be counterbalanced by increased dentine absorption. Approximal enamel in contrast is clearly visualized once maturation is complete. However, developmentally this enamel face initiates later, and is completed much earlier than buccal enamel. All of the radiographic estimates of crown completion times are based upon interpretations of approximal enamel completion. These considerations suggest that the human population standards in current usage may not represent true anatomical and chronological stages of crown development, and care should be taken in referring juvenile hominids to these radiological standards.
Animals↗
Variations in molar enamel thickness among primates.
Because of its hardness, resistance to abrasion and its influence on crown morphology, molar enamel thickness is an important factor in adaptation of the dentition to the diet. Enamel thickness has also been discussed extensively in relation to the phylogenetic relationships among the hominoids. The aims of this study were: (1) to analyse enamel thickness/tooth size relationships among primates as a whole, and (2) to evaluate variations in enamel thickness among hominoids against the background of the other primates. We employed measures of tooth size, and of enamel thickness and quantity based on measurements of areas in longitudinal sections of 125 molars of 39 species. Among primates, there were two grades of enamel thickness, prosimians having thinner enamel for a given tooth size or body weight than anthropoids. The scaling of enamel thickness with tooth size and body weight tended to show positive allometry among anthropoids. Comparison of hominoid enamel thicknesses with that in anthropoids led to the conclusion that Hylobates has enamel of average thickness, Homo has thick enamel and Gorilla has thin enamel, while Pan and Pongo had average or thin enamel, depending on tooth type. These results may be relevant to considerations of hominoid evolution.
Analysis of Variance↗
A histological reconstruction of dental development in the common chimpanzee, Pan troglodytes.
Much is known about the dental development of Pan compared with that for other extant great apes. The majority of information available has concentrated either on the emergence times of teeth or on the sequence of mineralization stages of the teeth as revealed from radiographs. However, the problems of defining stages of tooth formation sufficiently accurately on radiographs are only now becoming recognized. All of the data available to date suggest the presence of a more variable picture for the timing of mineralization stages in chimpanzees than for the timing of tooth emergence. In particular, arguments persist in the literature over the time of initial mineralization and the time it takes to form each anterior tooth crown in chimpanzees. Therefore we attempt to provide a more precise chronological time scale for dental development in our closest living relative. Furthermore, we examine the sequence of molar cusp formation relative to enamel formation times related specifically to those cusps and to try to tie these data in with information from functional studies of molar crowns. Histological sections of 14 maxillary and 28 mandibular teeth from four chimpanzee (Pan troglodytes) individuals and three molar teeth from three chimpanzees of unknown origin were prepared in accordance with a well-established protocol. By combining data on short-period and long-period incremental lines (including daily secretion rates, periodicity, prism lengths and enamel thickness) in both enamel and dentine, we reconstruct times for the onset and duration of crown formation as well as construct a schedule for the pattern and timing of dental development in this one hominoid species. Interestingly, our histologically-derived data confirms that the data from radiographic studies underestimate crown formation times by the following amounts for each tooth type: I1 2.5 years, I2 3.1 years, C 1.6 years, P3 1.9 years, P4 0.1 years, M1 0.8 years, M2 1.1 years and M3 0.3 years. When combined with data on gingival emergence, it seems that chimpanzee teeth have a greatly reduced time for root growth before emergence occurs and that the major differences between Homo sapiens and Pan lie in the first part of the root formation rather than in the total period of crown formation. Maxillary and mandibular molar functional cusps take longer to complete enamel formation to the cervix than any other cusp in that same tooth, which makes sense as these cusps are thick enamelled. These results suggest that new links can be made between developmental aspects, occlusal morphology and tooth function.
Aging↗
Infant feeding practices in Ottawa-Carleton: the introduction of solid foods.
Infant feeding guidelines regarding the introduction of solid foods are generally not well known in Canada. The guidelines recommend that solid foods be introduced between four to six months of age, depending on the developmental readiness of the infant. In order to understand the underlying factors and patterns which contribute to the introduction of solid foods in infants, data were analyzed from three cross-sectional surveys of parents of six-month-old infants from the Ottawa-Carleton region (n = 373, 1988; n = 330, 1992; n = 338, 1996) conducted by the Ottawa-Carleton Health Department. Multivariable analysis showed that mothers who: did not breastfeed, were younger, had lower education, smoked or had partners that smoked, and lacked support after birth, were more likely to introduce solid foods before four months of age. These data support the need for nutrition education programs to increase adherence to the new Nutrition for Healthy Term Infants guidelines.
Adult↗
Weight control in the workplace: a needs assessment for men.
This investigation was designed to assess the needs and interests of overweight men in a worksite weight control program. Employees of 2 high-tech companies were surveyed; 373 men and 238 women responded. 56% of respondents were interested in a worksite program. 44% of male respondents had a Body Mass Index (BMI) of 25 or greater and of those, 75% indicated an interest in participating. Among women, 21% had a BMI of 25 or greater and 92% were interested in the program. Also 68% of women who were not overweight would participate in a weight control program. There was a strong preference for a self-help teaching format over group activities, and particular interest in an evaluation of their present food habits, behaviour modification techniques for weight control and the health consequences of overweight. These findings give clear direction for the development of an effective worksite intervention.
Adult↗
Consumer understanding and use of fat and cholesterol information on food labels.
As part of a comprehensive study looking at consumer awareness of nutrition labelling, this descriptive market research evaluated the understanding and use of label information about fat and cholesterol. Mall intercept interviews of 149 food shoppers (80% women, 20% men) revealed that 60% believed it is extremely or very important to reduce their dietary fat. However, the claims "low in saturated fat" and "no cholesterol" and the term "non-hydrogenated" were often misunderstood. Fifty to 66% of respondents correctly interpreted "% B.F./M.F.", "low fat" versus "reduced in fat" claims, and the fat content of margarines. Only 18% used % B.F. information to choose cheese and yoghurt. Depending on the claim, 34-56% of respondents reported consulting other label information along with the claim; with the lowest rate of "additional consultation", (34%) reported for the "no cholesterol" claim. Consumer education is needed to enhance understanding and use of fat and cholesterol label information.
Adolescent↗
Tracking nutrition trends, 1989-1994: an update on Canadians' attitudes, knowledge and reported actions.
The National Institute of Nutrition tracks changes in Canadians' attitudes, understanding and reported actions related to nutrition issues--particularly fat cholesterol and fibre. Personal interviews were conducted in 1994 with a national sample of 1,953 adults, and the results were compared with data obtained in 1989. The number of people claiming that nutrition is of considerable importance in choosing their food has increased from 59% to 66%. More Canadians are now concerned about fat (82% vs 71%) and "chemicals" in foods (76% vs 68%) and more are planning to further reduce fat or increase fibre intake. Forty-three percent report having excellent or very good eating habits. The apparent use of food labels, lower fat/low--cholesterol products, and bran/high-fibre foods has grown in five years. Although awareness of nutrition terms has increased, understanding has changed little. The challenge is to build on consumer interest to reduce barriers to healthy eating through education and a supportive marketplace.
Adolescent↗