Trisomy 7 mosaicism, maternal uniparental heterodisomy 7 and Hirschsprung's disease in a child with Silver-Russell syndrome

Prenatal trisomy 7 is usually a cell culture artifact in amniocytes with normal diploid karyotype at birth and normal fetal outcome. In the same way, true prenatal trisomy 7 mosaicism usually results in a normal child except when trisomic cells persist after birth or when trisomy rescue leads to maternal uniparental disomy, which is responsible for 5.5-7% of patients with Silver-Russell syndrome (SRS). We report here on the unusual association of SRS and Hirschsprung's disease (HSCR) in a patient with maternal uniparental heterodisomy 7 and trisomy 7 mosaicism in intestine and skin fibroblasts. HSCR may be fortuitous given its frequency, multifactorial inheritance and genetic heterogeneity. However, the presence of the trisomy 7 mosaicism in intestine as well as in skin fibroblasts suggests that SRS and HSCR might possibly be related. Such an association might result from either an increased dosage of a nonimprinted gene due to trisomy 7 mosaicism in skin fibroblasts (leading to SRS) and in intestine (leading to HSCR), or from an overexpression, through genomic imprinting, of maternally expressed imprinted allele(s) in skin fibroblasts and intestine or from a combination of trisomy 7 mosaicism and genomic imprinting. This report suggests that the SRS phenotype observed in maternal uniparental disomy 7 (mUPD(7)) patients might also result from an undetected low level of trisomy 7 mosaicism. In order to validate this hypothesis, we propose to perform a conventional and molecular cytogenetic analysis in different tissues every time mUPD7 is displayed.     

Using the literature in developing McGill's guidelines for interactions between residents and the pharmaceutical industry.

Evidence suggests that the pharmaceutical industry exerts a large influence on residents' education and practice. Yet existing guidelines by professional bodies do not cover the specifics of residents' interactions with the pharmaceutical industry. At the psychiatry residency program of the McGill University Health Center, the authors set out to systematically evaluate areas of concern for residents and to develop guidelines for use by residents during and outside their training. Areas of concern included educational activities, training, fundraising, and other specific resident-industry interactions. In 1998, a committee of residents and faculty systematically evaluated areas of concern and, based on a review of the literature and discussions with experts, in 2000 developed guidelines for use by McGill's psychiatry program residents. The process for guideline development and methods for their implementation in 2001 are described. Education and training of residents on resident-industry interactions were included early in the curriculum. Guidelines were developed to address limitations on fundraising activities; restriction of direct gifts to residents; the appropriateness and awarding of industry fellowships; and the handling of drug samples, meals, and other presentations to residents. While guidelines for residents are useful adjuncts for guiding residents' interactions with the pharmaceutical industry, the authors conclude that they need to be reinforced with education and sensitization by faculty.     

The vascular lesions in vascular and mixed dementia: the weight of functional neuroanatomy

Vascular dementia appears rarer than previously thought, but the contribution of vascular lesions to cognitive impairment in Alzheimer's disease (AD) affected patients (mixed dementias) is now recognized as frequent. The role of strategic areas of the brain involved in the cognitive decline induced by vascular lesions and their relative contributions to the severity of the dementing process remain poorly understood. We determined the relationship between the severity of clinical dementia and the volume of different brain areas affected by infarcts in a prospective clinicopathological study in elderly patients. A volumetric study of the functional zones of Mesulam's human brain map affected by vascular lesions was made and correlations between quantified neuropathological data and the severity of dementia were performed in cases with large vascular lesions only, pure AD, and both lesions. The severity of cognitive impairment was significantly correlated with the total volume of infarcts but in a multi-variate model the volume destroyed in the limbic and heteromodal association areas, including the frontal cortex and in the white matter explained 50% of the variability in MMSE and GDS. The total volume of ischemic lesions explained only 0.1-5% of the variability in MMSE and GDS. Age only explained an extra of 0.1-1.6%. This study confirms that infarcts located in strategic areas have a role in the mechanism of cognitive impairment and brings a key for their quantification. It may be useful for developing neuropathological criteria in multi-infarct and mixed dementias.     

Isodicentric/pseudoisodicentric chromosome 21 amplification in four cases of acute myelocytic leukemia or myelodysplasia

The bone marrow karyotypes of three patients with acute myelocytic leukemia (AML) or myelodysplastic syndrome (MDS) were studied at diagnosis and revealed, multiple copies of the same chromosomal anomaly, considered as psu idic(21)(q22) associated with other rearrangement(s). The karyotype of a fourth patient with MDS in transformation showed one copy of a dicentric marker presumably derived from a similar psu idic(21) by (tandem?) interstitial amplification of part of its structure, resembling a "homogeneous staining region", and described as der(21)psu idic(21)(q22)hsr(21)(q22). This rearrangement, previously described in isolated cases only, might be considered as recurrent in AML/MDS and associated with an unfavorable prognosis. It is most probably a secondary change, because it was never observed as sole abnormality and the main association, as for trisomy 21, was with del(5q). In the four cases, the number of partial supernumerary segmental 21pter-->21q22 copies, ranged from 2 to 10. The AML1 gene did not appear to be the common target of this amplification because this locus had been lost by the psu idic(21) in one patient     

The seroepidemiology of human T-lymphotropic viruses: types I and II in Europe: a prospective study of pregnant women

BACKGROUND: Up to 20 million persons are infected with the human retroviruses human T-lymphotropic virus (HTLV)-I and HTLV-II globally. Most data on the seroprevalence of HTLV-I and HTLV-II in Europe are from studies of low-risk blood donors or high-risk injection drug users (IDUs). Little is known about the general population. METHODS: A prospective anonymous study of HTLV-I and HTLV-II seroprevalence among 234,078 pregnant women in Belgium, France, Germany, Italy, Portugal, Spain, and the United Kingdom was conducted. Maternal antibody status was determined by standard methods using sera obtained for routine antenatal infection screens or eluted from infant heel prick dried blood spots obtained for routine neonatal metabolic screens. RESULTS: Anti-HTLV-I/II antibodies were detected and confirmed in 96 pregnant women (4.4 per 10,000, 95% confidence interval [CI]: 3.5-5.2). Of these, 73 were anti-HTLV-I, 17 were anti-HTLV-II, and 6 were specifically anti-HTLV but untyped. The seroprevalence ranged from 0.7 per 10,000 in Germany to 11.5 per 10,000 in France. CONCLUSIONS: Pregnant women better reflect the general population than blood donors or IDUs. The seroprevalence of HTLV-I and HTLV-II in Western Europe is 6-fold higher among pregnant women (4.4 per 10,000) than among blood donors (0.07 per 10,000). These data provide a robust baseline against which changes in HTLV-I and HTLV-II seroprevalence in Europe can be measured.     

Analysis through mathematical models of the dynamics of the adrenal cortical response to ACTH in the rat

The distribution and metabolism of ACTH and the dynamics of the adrenal cortical response to this tropic hormone were characterized in the rat, through mathematical models involving data derived from experiments, where plasma corticosterone concentrations were measured following both single injections and infusions of ACTH. The models, which incorporate a previously established model of the dynamics of plasma corticosterone, were statistically validated. The simulated dynamics of the different processes linking ACTH secretion by the adenohypophysis to corticosterone secretion by the adrenal cortex include: (1) a variable MCR for plasma ACTH, modeled as the sum of a constant and a saturable degradation process; (2) the ability of the adrenal gland to secrete at a maximal rate aven after the plasma ACTH concentration has become negligible, modeled as the accumulation of an intermediary productZ directly controlled by the plasma ACTH concentration; (3) a saturable secretion with a small time constant and which, for single injections, always starts in the same fashion, modeled as a “synthesis process” whose input is a saturable function ofZ; (4) an immediate fall of the plasma corticosterone concentration at the end of the ACTH infusions, modeled as a “release process” also controlled byZ. Supported by grants from the Medical Research Council of Canada (MT-1205, MT-1555, and MA-4970), and from INSERM, France (CRL-76-5-020-4).     

46,XY gonadal dysgenesis: evidence for autosomal dominant transmission in a large kindred

46,XY gonadal dysgenesis is characterized by abnormal testicular determination. We describe a large kindred in which various disorders of sexual development were observed, ranging from completely female phenotype without ambiguities of the external genitalia (five cases) to men with isolated penile or perineal hypospadias (four cases), including two cases with moderate virilization and one case with ambiguity of the external genitalia. Histologic examination of gonadal tissue was performed on seven subjects. These findings were suggestive of complete gonadal dysgenesis in one patient, partial gonadal dysgenesis in three patients, and mixed gonadal dysgenesis in three patients. Four patients developed gonadal tumors (two gonadoblastoma, two dysgerminoma, and one immature teratoma, i.e., one patient had a dysgerminoma with some areas of gonadoblastoma). All affected subjects had no other congenital anomalies or dysmorphic features. Analysis of families with several affected individuals with 46,XY gonadal dysgenesis implied an X-linked mode of inheritance because of the apparent absence of male-to-male transmission. However, a sex-limited autosomal dominant mode of inheritance affecting only XY individuals could not be ruled out. Analysis of the pedigree we report indicated an autosomal dominant mode of inheritance because of male-to-male transmission. This kindred supports the involvement of at least one autosomal gene in non-syndromic 46,XY gonadal dysgenesis.