Polymorphic microsatellite loci from the endangered Giant Otter (Pteronura brasiliensis)

We describe the first microsatellite loci isolated from the giant otter (Pteronura brasiliensis), an endangered mustelid endemic to South America. Fourteen di- and trinucleotide polymorphic loci were characterised in fourteen individuals from the Pantanal wetlands, Central Brazil. Number of alleles per locus ranged from 2 to 5, and average observed heterozygosity was 0.577. Two loci were in linkage disequilibrium, and one further locus deviated from Hardy–Weinberg equilibrium, probably due to the presence of null alleles. The transferability of these markers to two other mustelids (Lontra longicaudis and Eira barbara) and to the mephitid Conepatus semistriatus was also evaluated. These loci are useful to study the ecology and evolution of these species.     

Biochemical bone markers in the assessment and pamidronate treatment of children and adolescents with osteogenesis imperfecta

Aim: To assess the role of biochemical bone markers in classification of children with osteogenesis imperfecta (OI), their possible association with vertebral compression fractures in milder forms of OI and their role in monitoring of intravenous pamidronate (APD) treatment. Methods: Serum total alkaline phosphatase (ALP), bone ALP isoforms (in a subgroup), osteocalcin, type I procollagen carboxy‐terminal propeptide, carboxy‐terminal telopeptide of type I collagen, and urine deoxypyridinoline (DPD) were measured in a cross‐sectional study of 130 untreated individuals, 0.25–20.9 years (median 6.7), with OI types I, III and IV. Of those, sixty‐nine were also assessed longitudinally during monthly APD treatment. Bone mineral density (BMD) was measured by dual‐energy X‐ray absorptiometry. Results: Significant differences in bone markers, however not sufficient for individual clinical use, were found in the larger untreated group but not between subgroups with or without vertebral compressions. All bone markers decreased during treatment for 1.0–12.5 years, but with different relative amounts. Changes were not correlated to the improvement in BMD, mobility or pain. Conclusion: Bone markers are, despite significant differences, not useful for the classification of OI type in the individual child and are not associated with vertebral compressions. Serum ALP and urinary DPD are sensitive in monitoring bisphosphonate treatment.     

Associations between androgen and Vitamin D receptor microsatellites and postmenopausal breast cancer.

We investigated the association between polymorphism in the androgen receptor (AR) and vitamin D receptor (VDR) genes and breast cancer risk in a large population-based case-control study of genetically homogenous Swedish women. We successfully determined both AR CAG(n) and VDR A(n) genotype in 1,502 women with invasive breast cancer and in 1,510 control women. We did not find any associations between AR or VDR microsatellite lengths and breast cancer when we used a priori determined cutoffs (/=22 repeats for AR and /=19 for VDR) to define long and short alleles. There was statistically significant interaction between VDR genotype and parity, such that women with two short alleles had a halved risk for breast cancer, irrespective of parity, compared with nulliparous women with two long alleles. Homozygosity for the long VDR allele was associated with a more advanced clinical stage at diagnosis. In exploratory analyses, we determined cutoffs based on visual inspection of distributions of allele lengths among cases and controls and found that women carrying two alleles with <20 AR CAG(n) repeats had an increased risk for breast cancer, odds ratio of 1.67 (95% confidence interval, 1.17-2.38), compared with those with two alleles with >/=20 repeats. Women carrying two VDR alleles with <21 A(n) were also at an increased risk, odds ratio of 1.26 (95% confidence interval, 1.04-1.51). Our data do not support major roles for AR or VDR polymorphism as breast cancer risk factors. However, we did find an interaction between VDR genotype and parity that remains to be corroborated.     

Effects of restrained cervical mobility on voluntary eye movements and postural control

The effects of restrained cervical mobility on pursuit eye movements (PEMS), voluntary saccades and postural control, as measured by posturography, were studied in 11 healthy subjects whose cervical spine movement had been restrained for 5 days by means of a rigid neck-collar. At day 5 mean peak velocity of voluntary saccades at amplitudes of 40 degrees and 60 degrees was significantly reduced, as was mean peak gain of PEMs at a stimulus velocity of 50 degrees/s; the variance of body position in vibration-induced body sway was significantly increased, but there was no difference in variance of galvanically-induced body sway or in velocity of vibration-induced body sway. The results suggest that restriction of cervical movements per se affects voluntary eye movements, a conclusion also consistent with findings in patients with tension headache. Restriction of cervical movement only marginally affects postural control.     

Effect of proprioceptor stimulation on postural stability in patients with peripheral or central vestibular lesion

Body sway in upright stance at rest and after inducing proprioceptor stimulation, elicited by vibration applied to the calf or neck muscles, was studied in 11 patients with peripheral lesion and in 17 patients with central vestibular lesion. The responses were compared with those of 20 normal subjects. Vibratory stimulus was applied at five different frequencies, ranging from 32 to 150 Hz, and at a constant amplitude of 2.1 mm. Postural stability was measured with a force platform in terms of average deviation of body position (ADBP) analyzed in relation to the individual maximum support distance in the anterio-posterior direction. In patients with peripheral vestibular lesion ADBP was moderately increased, compared to normal subjects, when the calf muscles were exposed to vibration under eyes closed conditions (i.e. no visual information available); stimulation of neck muscles both under eyes open and eyes closed conditions and stimulation of calf muscles with open eyes produced an ADBP of the same magnitude as in controls. In patients with central vestibular lesion, proprioceptor stimulation of calf and neck muscles caused increased ADBP whether with eyes open or closed. The ADBP induced by stimulation of neck muscles was significantly greater in patients with a central lesion than in those with a peripheral vestibular lesion. The results indicate that patients with peripheral lesion differ from those with central vestibular lesion in their reaction to proprioceptor stimulus; and that in patients with central vestibular lesion proprioceptor stimulation of the neck muscles produces disproportionately powerful cervico-collic reflexes.