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Biomedical subjects

J Varrela

Publications and source records attributed to J Varrela.

33 records · Page 2Linked to original sources
PubMed1990

Taurodontism in 45,X females.

Orthopantomograms of 87 45,X females, 61 first-degree female relatives of these females, and a population sample of 113 normal females and 44 normal males were examined for the occurrence of taurodontism in mandibular molars. In the sample of 45,X females, two showed taurodont lower molars. In one of them, a hypotaurodont second molar was detected, while hypotaurodont third molars were found in the other. Three of the females' relatives and four of the population control females showed taurodontism, three unilaterally and four bilaterally. In all cases, the affected teeth were hypotaurodont. The results suggest that taurodontism occurs in 45,X females with a frequency similar to that in normal females. This result is not in accordance with the hypothesis that low mitotic activity of the chromosomally abnormal cells is an etiological factor in the development of taurodontism. The present findings, together with earlier results, suggest that the gene content of the X chromosome, rather than the amount of heterochromatin, is the cause of taurodontism in individuals with chromosome aneuploidy.

Adult↗
PubMed1990

Caries occurrence in Klinefelter syndrome men (47,XXY males).

Men with the Klinefelter syndrome (47,XXY males) and their brothers were studied as regards their caries experiences as part of a comprehensive study on oral facial growth and health in individuals with sex chromosome anomalies. The results show that caries experience was greater among the 47,XXY men than among their normal brothers, and a greater proportion of the 47,XXY men's cumulative caries experience consisted of extractions.

Adult↗
PubMed1989

Taurodontism in females with extra X chromosomes.

The association between taurodontism and extra X chromosomes was studied in four 47,XXX-females and in two 48,XXXX-females. Occurrence of the trait in the permanent mandibular molars was noted from orthopantomograms. Five first-degree relatives and a sample of 157 normal males and females were investigated as controls. Two of the 47,XXX-females and both 48,XXX-females each had at least one mandibular molar classified as taurodont. The two affected 47,XXX-females had hypotaurodont or mesotaurodont teeth, whereas both 48,XXXX-females showed hypertaurodontism. The manidubular molars of the other two 47,XXX females had normal root morphology. The only control relative with taurodont teeth was a sister to a 48,XXXX-female. In the population control group, four females had taurodont teeth. These results support the concept that a prevalence of taurodontism increases as the number of X chromosomes increases and also indicate that expression of the trait and the number of X chromosomes may be positively correlated. It is suggested that the X chromosome gene(s) influencing development of enamel may be involved in the development of taurodontism.

Female↗
PubMed1988

Tooth crown size in human females with 45,X/46,XX chromosomes.

Permanent tooth sizes in 15 Finnish females with a 45,X/46,XX chromosome constitution were measured and compared with those of normal females, first-degree female relatives and 45,X females. Mesiodistal crown diameters of the 45,X/46,XX mosaic females were smaller than those of normal females but similar to those of females with pure 45,X chromosome constitution. Labiolingual crown diameters of the 45,X/46,XX mosaics were near normal, being consistently larger than those of 45,X females. The mesiodistal crown sizes are consistent with a decrease in enamel thickness in 45,X/46,XX mosaic females. The difference in labiolingual dimension between teeth of 45,X/46,XX mosaic females and 45,X females may relate to a gradual normalization of growth when normal 46,XX cells are mixed with defective 45,X cells.

Chromosome Aberrations↗
PubMed1988

Taurodontism in 47,XXY males: an effect of the extra X chromosome on root development.

Effects of an extra X chromosome on root development were studied in males with a 47,XXY chromosome constitution. Occurrence of taurodontism in the permanent molars of the lower jaw was noted from orthopantomograms of 30 Finnish 47,XXY males, 16 of their first-degree relatives, and a sample of 157 normal males and females. Nine, or 30%, or the 47,XXY males had at least one mandibular molar which was classified as taurodont. Only hypotaurodont teeth were found, and the teeth affected were all either second or third molars. None of the control relatives showed taurodontism. In the population sample, four individuals, or 2.5%, had taurodont teeth. A change in the mitotic activity of the cells of the developing teeth is one possible factor that can affect root formation leading to the development of taurodontism.

Adolescent↗
PubMed1985

Effects of the Y chromosome on quantitative growth: an anthropometric study of 47,XYY males.

The aim of the study was to investigate the effects of the Y chromosome on different body and head dimensions of 47,XYY males, and especially its effect on their body proportions. From seven adult 47,XYY males 25 anthropometric measurements were recorded and compared with four male relatives and 42 control males. In most dimensions 47,XYY males were larger than the normal males, the difference being mainly between 0.5 and 1.5 S.D. units. The body proportions of 47,XYY males were found to be similar to those of the normal males when the effect of size was allowed for. It is concluded that the extra Y chromosome in 47,XYY males causes an increase in their growth without affecting the body proportions. This finding suggests that the Y chromosome contains gene(s) which affects growth by increasing its quantitative outcome. This effect may be mediated by a direct action of the Y chromosome on the cells. It also may seem that the Y chromosomal gene(s) influence the development of the sex difference in height and body size.

Adult↗
PubMed1984

Effects of X chromosome on size and shape of body: an anthropometric investigation in 47,XXY males.

The effects of an extra X chromosome on size and shape of body and head were studied in 47,XXY males; 25 anthropometric measurements were recorded from 29 adult 47,XXY males and compared with those of male relatives and control males. In stature, arm length, leg length, triceps skinfold, and subscapular skinfold 47,XXY males were larger and in biacromial diameter, bideltoid breadth, wrist breadth, and in most head dimensions smaller than normal males. Arm length was increased less than leg length. Increase in stature seemed to be caused solely by increased leg length, and the somewhat feminine proportions in trunk were caused by decrease in biacromial diameter. Correlations of the body and head dimensions between 47,XXY males and their male relatives were found to be normal. The present findings support the earlier proposals that X chromosome carries genes which influence linear growth. It is suggested that the reduction in biacromial diameter is caused by lowered plasma testosterone level which may also have affected sitting height. The control of body and head dimensions seems to be maintained relatively normal.

Anthropometry↗
PubMed1984

Body size and shape in 46,XX males: an anthropometric investigation.

Anthropometric measurements of four 46,XX males are compared with those of their first degree male relatives, control males, and a sample of 47,XXY males. Most dimensions of 46,XX males are smaller than those of normal males. 46,XX males are also shorter and smaller than 47,XXY males. The present results support the earlier suggestion that there is a gene(s) in the Y chromosome with a general size-increasing effect and that the Y chromosome has an active role in the development of sex dimorphism in many body dimensions. These four 46,XX males may possess the Y chromosomal gene which sets the later timing of development in males.

Adult↗
PubMed1980

Permanent tooth sizes in 46,XY females.

The teeth of seven Finnish patients with complete testicular-feminization syndrome (46,XY females) were studied to obtain further information about their growth and possible somatic determinants on the Y chromosome. The sizes of the permanent teeth of the 46,XY females were found to be as large as those of control males and definitely larger than those of control females. Testicular feminization is caused by androgen insensitivity, and persons affected are phenotypically females. Hence, these results also indicate the influence of the Y chromosome on dental determination.

Adolescent↗
PubMedDate not supplied

The phenotype of 45,X females: an anthropometric quantification.

Twenty-five anthropometric measurements were recorded from 48 adult 45,X females, 24 of their first-degree female relatives, and 95 control females. When 45,X females were compared with their female relatives and control females they were smaller in most dimensions, the largest differences being found in weight, stature, sitting height, arm length, leg length, bi-iliac diameter, bitrochanteric breadth and wrist width. No significant differences were found in head dimensions. The comparison after allowance for size showed that 45,X females are relatively smaller in stature, sitting height, arm length, leg length and bitrochanteric breadth and larger in bideltoid breadth, waist breadth, upper arm circumference, chest circumference and triceps skinfold. However, in proportion to height the relative lengths of sitting height, arm length and leg length were similar to those of normal females. The mother-45,X daughter correlation coefficients were significantly larger than those of sister-45,X sister pairs in body dimensions whereas they were more similar in head dimensions. The present findings suggest the presence of genes on the X chromosome having effect on growth in general. This conclusion is in accordance with the results of several earlier studies which have indicated an X-chromosomal influence on stature, tooth size and enamel thickness.

Adolescent↗
PubMedDate not supplied

Body size and shape in 46,XY females with complete testicular feminization.

Twenty-five anthropometric measurements were recorded from eight adult 46,XY females with complete testicular feminization and they were compared with those of female relatives of the patients and control females. In most dimensions 46,XY females were larger than normal females, the difference being close to one SD unit. The mean height of 46,XY females was 171.5 cm. The body proportions of 46,XY females were similar to those of normal females though, according to the results of analysis of covariance where the effect of size was controlled, there may be a tendency to slimmer body. The present findings suggest the presence of genes on the Y chromosome with a general size-increasing effect. They also indicate that the Y chromosome has an influence on the quantitative sex difference in body size. These conclusions are in accordance with the results of earlier studies which have indicated Y-chromosomal influence on stature and tooth size.

Androgen-Insensitivity Syndrome↗
PubMedDate not supplied

Effect of sex chromosome aneuploidy on growth of human skin fibroblasts in cell culture.

Growth of human skin fibroblast lines with sex chromosome aneuploidy was studied in cell culture. Two lines were derived from individuals with 45,X and two from individuals with 47,XYY chromosome constitution. The aneuploid cell lines were compared with normal skin fibroblasts derived from age-matched same-sex siblings. To ensure similar conditions in culture, each study-control pair was treated simultaneously and equally in all steps. Growth in both 45,X cell cultures slowed down earlier than in control cultures. One of the 47,XYY cultures grew faster and the other at a similar speed to the control culture. Thus, the 45,X cell lines seemed to have lesser, and one of the 47,XYY cell lines greater, growth potential than the 46,XX and 46,XY cells, respectively. These differences in the final cell numbers may relate to changes in the rate of cell division of the aneuploid cell lines. However, the results do not support the hypothesis that an increasing number of sex chromosomes decreases the rate of cell division.

Adolescent↗