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Biomedical subjects

J C Stevenson

Publications and source records attributed to J C Stevenson.

At least 199 records · Page 11Linked to original sources
PubMed1979

A physiological role for calcitonin: protection of the maternal skeleton.

Plasma-calcitonin levels, measured with an established and reliable extraction radioimmunoassay technique, were significantly higher throughout normal pregnancy and lactation than in normal non-pregnant women, and were not immediately influenced by the acute stimulation of breast-feeding. Thus, more calcitonin circulates at times of physiologically increased calcium need. It is suggested that an important function of calcitonin is the protection of the healthy maternal skeleton from excessive resorption by opposing the resorptive action of 1,25-dihydroxycholecalciferol on bone.

Adolescent↗
PubMed1978

Relative deficiency of plasma-calcitonin in normal women.

A new radioimmunoassay technique was used to measure plasma-calcitonin in normal subjects. Plasma-calcitonin concentrations in women were less than 25% of those in men, and were often undetectable. However, during pregnancy or administration of the oestrogen-progestagen contraceptive pill, plasma-calcitonin equalled or exceeded male concentrations. These findings are consistent with an effect on calcitonin production of normal male testosterone concentrations and concentrations of the sex steroids during pregnancy. Calcitonin may protect the skeleton during calcium stress. Further, although it is unknown whether a deficiency of the hormone plays a role in postmenopausal osteoporosis, this is now a definite possibility which requires urgent investigation.

Adolescent↗
PubMed1978

Distribution of HLA antigens in Polish and German populations in Milwaukee, Wisconsin.

Gene and haplotype frequencies for HLA-A and HLA-B antigens were determined in Milwaukee blood donors of German and Polish descent. Gene frequencies for A25 and B18 were significantly higher in Poles than in Germans. Significant gametic associations were noted for A1-B8, A29-B12 and AW30-B13 in both populations. Gametic association for A3-B7 was only found in Germans, while the A25-B18 haplotype frequency was significantly increased in Poles. Since the latter haplotype has also been found in Yugoslavs, Ukrainians and Czechs, it is possible that A25-B18 represents a Slavonic marker.

Female↗
PubMedDate not supplied

Attention-deficit hyperactivity disorder (AD/HD) and fluctuating asymmetry (FA) in a college sample: an exploratory study.

Departures from normal development can be partly assessed by measuring fluctuating asymmetry (FA), that is, differences from perfect symmetry in traits that display bilateral symmetry. Attention-deficit hyperactivity disorder (AD/HD), one of the most common psychiatric conditions, is diagnosed if there are developmentally inappropriate levels of inattention, hyperactivity, and impulsivity. The objective here is to measure whether AD/HD behaviors positively correlate with FA in head, hands, and fingerprints of a sample of college students (n = 176, 57 male, 119 female) not selected for AD/HD. FA was measured as the absolute value of the difference between right and left sides divided by group mean trait size. Average FAs (mean, SE) were lowest for finger lengths (e.g., male, 3rd, 0.011 +/- 0.001; female, 3rd, 0.012 +/- 0.001) and highest for digit ridge counts (e.g., male, 5th, 0.075 +/- 0.007; female, 2nd, 0.069 +/- 0.005). Average FAs were similar between the sexes and only one facial measure and the facial index (summed FAs) differed significantly between the sexes (F > M). The scores for measures of the adult AD/HD behavioral assessment instrument, the Wender Utah Rating Scale (WURS) were high overall in this sample and males exhibited higher rates of symptoms than females. A Rasch measurement model analysis of individual responses to the WURS produced a true interval score for each person that is a measure of individual "AD/HDness." FA indices were then regressed on Rasch scores. A univariate analysis of all the variables demonstrated a significant interaction of sex. Hand, Dermatoglyphic, Face, and Total Indices were then regressed by sex on the Rasch values of "AD/HDness." Only in males was there a trend for the Dermatoglyphic Index (F(1,55) = 3.627, P = 0.062) and Total Index (F(1,55) = 3.811, P = 0.056) to increase as AD/HDness increases.

Adolescent↗
PubMedDate not supplied

Attention-deficit hyperactivity disorder and fluctuating asymmetry in another college sample.

Attention deficit/hyperactivity disorder (AD/HD) represents a developmental lag that may be reflected in fluctuating asymmetry (FA), i.e., differences from perfect symmetry in traits that display bilateral symmetry. Burton et al. (2003 Am. J. Hum. Biol. 15:601-619) found a statistical trend for FA to increase (as dermatoglyphic index or as total index) as the behavioral measure for AD/HDness (Rasch logit values derived from the Wender Utah Rating Scale, or WURS) increased in males but not in females. The objective here was to do a similar study in an independently collected sample of college students (n = 222; 61 male, 161 female) not selected for AD/HD, looking at FA vs. symptoms for AD/HD based on Rasch versions of responses to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) (Barkley and Murphy 1998 Attention-Deficit Hyperactivity Disorder, New York: Guilford Press, p. 95-96) and the more comparable shortened WURS. FAs were lowest for body and ear height, and highest for eye width and nose width, and ranged from 0.01 +/- 0.001 (mean +/- SE) for foot and ankle widths to 0.13 +/- 0.01 in eye and nose widths for both sexes; the sexes did not differ significantly. Males displayed higher AD/HD symptom rates overall. There was a significant correlation between body FA and the WURS measure in females after Bonferroni correction (P = 0.002, r(2) = 0.058). Thus, AD/HD symptoms levels increased with an increase in body FA in female college students not selected for AD/HD.

Adolescent↗
PubMedDate not supplied

Attention deficit/hyperactivity disorder (ADHD) symptoms and digit ratios in a college sample.

Diagnosticians recognize three subtypes of attention deficit/hyperactivity disorder (ADHD) if there are developmentally inappropriate levels (six or more symptoms) of Hyperactive-Impulsive behavior, or Inattentive behavior, or both (Combined), respectively. ADHD may partly reflect androgen dysfunction, and an arguable proxy for prenatal androgen exposure is the 2D:4D finger ratio set at least as early as week 9 in the fetus; this is lower in men than in women. We examined the relationship between digit ratios and ADHD symptoms representing the three phenotypes: ADHD/Combined as measured by "summarized" (Rasched) scales, i.e., 1) the short version of the Wender Utah Rating Scale (WURS) and a total symptom list derived from the DSM IV, and the subdivided DSM IV into 2) ADHD/Inattentive and 3) ADHD/Hyperactive-Impulsive inventories, in a sample of European-descent college students (135 female, 52 male) not selected for ADHD. All digit ratios were calculated excluding the thumb. There were significant sex differences for the 2D:4D digit ratios of both hands (RH and LH), and between the RH 3D:4D and between the LH 2D:3D ratio. In females, the more masculine the LH 2D:4D ratio, the more the ADHD/Combined symptoms (both WURS and DSM) and the more the ADHD/Inattentive symptoms and ADHD/Hyperactive-Impulsive symptoms. More masculine ratios also correlated between the total WURS and RH 2D:3D, RH 2D:4D, and LH 2D:3D; and between the inattentive DSM symptoms and LH 2D:5D, and between the ADHD/Hyperactive and Impulsive symptoms and RH 3D:4D.

Adolescent↗
PubMedDate not supplied

Modified method of spinal computed tomography for trabecular bone mineral measurements.

Quantitative CT of vertebral trabecular bone is established as a sensitive technique for assessing bone mineral mass in the axial skeleton. We have adapted this technique for use in a standard third generation whole body CT scanner without requiring any extra equipment or software. By utilizing a maximum area of interest in the vertebral trabecular bone, we have developed a method of bone mineral content estimation that is precise, accurate, and a more representative measurement of the vertebral trabecular bone. Measurements in 70 healthy postmenopausal women have shown that our results compare favourably with those from other centres. Our findings demonstrate that the technique of quantitative CT of bone can be adapted for advanced CT scanners without any modifications being required. This should lead to an increase in availability of such measurements, resulting in improvements both in the diagnosis of metabolic bone diseases and in the efficacy of treatment.

Adult↗
PubMedDate not supplied

Prevention of osteoporosis. Current recommendations.

Osteoporosis and its treatment have attracted much attention in recent years, especially since the widespread recognition of its association with the menopause. The resulting fractures are a cause of considerable morbidity and mortality in the elderly, and current costs of treating these patients has been estimated to be in excess of pounds 500 million per annum in the UK. As the causes of osteoporosis are now recognised the condition may be largely preventable, especially in women, and significant savings in health expenditure could be made if preventive methods are applied to those most at risk. The most well researched preventive treatment for osteoporosis is hormone replacement therapy (HRT) which offers additional benefits to those who choose it. Alternative methods currently under investigation for those who cannot or will not use HRT include those agents which inhibit the resorption of bone and those that stimulate the production of new bone. Treatment of established disease, i.e. attempts at increasing bone density in those with significant loss, is more difficult and methods so far investigated are not without risks and adverse effects. Furthermore, whether an increase in bone mineral density results in a reduced rate of fracture incidence has yet to be confirmed.

Female↗