公共资源与最优产权选择

公共资源是指在产权界定过程中，资源所有者被迫放弃或者没有进行产权界定的资源部分,而产权界定本质上是划分公共资源归属权的过程。根据组织对公共资源控制权的性质，将其分为两类——组织间公共资源和组织内公共资源，并据此将产权界定、生产和交易纳入同一个分析框架中。通过分析，认为随着公共资源范围的变化，不同产权形成一个相互联系和转化的系列，即从资源非稀缺条件下的纯公共产权到资源全为废弃物的纯公共产权系列；不可交易的所有权是产权系列中的特殊形式，私人产权和俱乐部产权是这一系列中的过渡形式；组织内和组织间的均衡博弈结构决定最优产权的具体选择形式。     

Personal desires of patients and social obligations of geneticists: applying preimplantation genetic diagnosis for non-medical sex selection

The arguments against the use of preimplantation genetic diagnosis (PGD) for non-medical sex selection are analysed. It is concluded that the distinction between medical and non-medical reasons is difficult to maintain, that the disproportionality of means and end is not a decisive counterargument and that the fear of damage to the reputation of PGD does not justify the refusal of controversial applications. Moreover, since non-medical sex selection does not belong to basic health care, it should not be equally accessible to all. The position defended in this article is founded on two basic principles: (1) medical reasons have priority on non-medical reasons, and (2) personal reasons do not qualify for public funding. In order to respect both principles, it is proposed that restrictions should be installed to control the number of requests for social sexing and that a tax should be imposed on these elective services. The tax should compensate the society for the investment it made in the training and education of the physician. Copyright © 2002 John Wiley & Sons, Ltd.     

Duplex PCR for preimplantation genetic diagnosis (PGD) of spinal muscular atrophy

The main difficulty in developing a molecular diagnosis of spinal muscular atrophy (SMA) resides in the specific genomic structure of the locus. Indeed, two highly homologous survival motor neurone genes, SMN1 and SMN2, are present at the locus. The detection of the homozygous deletion of exons 7 and 8 of the SMN1 gene, which is present in 90 to 98% of the patients, is based on methods highlighting 1 of the 8 nucleotidic mismatches existing between these 2 genes. In order to offer preimplantation genetic diagnosis (PGD) for SMA, we developed a new allele-specific amplification method. The main disadvantage of our previously described strategy resided in the possibility of diagnosing, in case of amplification failure, an unaffected embryo as affected. We present here a new PGD-SMA method. We established the conditions for three different duplex PCRs, allowing the specific detection of the SMN1 gene and one polymorphic marker, either D5S629, D5S1977, or D5S641. Of the 60 to 90 single cells tested, the PCR efficiency varied from 98 to 100% with a complete genotype obtained in a range between 81 and 87% with a global allele drop-out rate of 9%. Such a test was used to perform 1 PGD cycle for which 7 embryos could be analysed. All the embryos were fully diagnosed, six as unaffected and one as affected. Four embryos were transferred, but no pregnancy ensued. Copyright © 2003 John Wiley & Sons, Ltd.     

Preimplantation genetic diagnosis using FISH for carriers of Robertsonian translocations: the Portuguese experience

Preimplantation genetic diagnosis (PGD) is an alternative to prenatal diagnosis for couples at risk of transmitting genetic disorders to their offspring. We present a fluorescence in situ hybridization (FISH) analysis of embryos obtained after seven PGD cycles in six couples with Robertsonian translocations and male factor infertility: 4 der(13;14), 1 der(14;21) and 1 der(15;21). Of 74 metaphase II (MII) injected oocytes, 61 (82.4%) fertilized normally and cleaved. Of these, 37/61 (60.7%) embryos were of high morphological quality with ≥6 blastomeres. After biopsy of 44 embryos at day 3 of development, seven degenerated, seven arrested in development and 30/44 (68.2%) evolved, of which 25/30 (83.3%) reached the morula/blastocyst stage. Analysis of biopsied blastomeres showed 23/44 (52.3%) of normal/balanced embryos, of which 15 (11 at the morula/blastocyst stage) were transferred in six cycles. One term pregnancy was achieved, which ended by cesarean section at 37 weeks of gestation, giving birth to two healthy newborn. Analysis of 49 embryos (excluding 12 inconclusive cases) showed a predominance of alternate segregation (38/49, 77.6%) over adjacent segregation (7/49, 14.3%), with one (2%) being a polyploid mosaic and three (6.1%) chaotic. Copyright © 2002 John Wiley & Sons, Ltd.     

A comparative analysis of predictors of sense of place dimensions: attachment to, dependence on, and identification with lakeshore properties

Sense of place can be conceived as a multidimensional construct representing beliefs, emotions and behavioural commitments concerning a particular geographic setting. This view, grounded in attitude theory, can better reveal complex relationships between the experience of a place and attributes of that place than approaches that do not differentiate cognitive, affective and conative domains. Shoreline property owners (N=290) in northern Wisconsin were surveyed about their sense of place for their lakeshore properties. A predictive model comprising owners' age, length of ownership, participation in recreational activities, days spent on the property, extent of property development, and perceptions of environmental features, was employed to explain the variation in dimensions of sense of place. In general, the results supported a multidimensional approach to sense of place in a context where there were moderate to high correlations among the three place dimensions. Perceptions of environmental features were the biggest predictors of place dimensions, with owners' perceptions of lake importance varying in explanatory power across place dimensions.     

Prenatal diagnosis of Fukuyama congenital muscular dystrophy

Fukuyama congenital muscular dystrophy (FCMD) is characterized by infantile hypotonia, symmetrical generalized muscle weakness, and neuronal migration disturbances that result in changes consistent with cobblestone lissencephaly with cerebral and cerebellar cortical dysplasia. FCMD is recognized as an autosomal recessive genetic defect. Genetic counselling is recommended for parents at risk of having a child with FCMD. Given the high risk and overwhelming prospect of having another child with this incurable devastating condition leads many couples to consider prenatal diagnosis. In Japanese families, haplotype analysis using microsatellite markers is available. In non-Japanese families, DNA sequence analysis is available. Both disease-causing alleles of an affected family member must be identified before prenatal testing can be performed. Copyright © 2006 John Wiley & Sons, Ltd.     

Prenatal diagnosis of trisomy 9. Six cases and a review of the literature

Six prenatally diagnosed cases of trisomy 9 are reported and 22 previously reported cases are reviewed; the difficulty of genetic counselling for such cases and the variation in the percentage of trisomic cells in different tissues, thus making accurate diagnosis of trisomy 9 difficult, are emphasized. In addition to karyotyping results, ultrasound findings are important in achieving diagnoses. Finally, a course of action when prenatal trisomy 9 is detected is proposed.