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Biomedical subjects

F C Fraser

Publications and source records attributed to F C Fraser.

At least 19 recordsLinked to original sources
PubMed1979

Genetic counseling: provision and reception of information.

To explore verbal communication between family and counselor, transcripts of 30 tape-recorded or observed genetic counseling sessions are analyzed qualitatively. In half the cases, available data did not allow counselors to give parents a single estimate of the recurrence rate. Moreover, limits on the language available for communicating small probabilities made common the use of nonnumerical statements about a family's chance of having an abnormal child. Counselees processed the factual information they were given, most commonly translating recurrence rates in ways that emphasized the uncertainties associated with them. They tended to view these rates in binary form and requested guidelines for their behavior, indicating uncertainty about how to proceed with reproductive decision-making. The findings suggest that strategies for processing information are an important element influencing parental perspectives on and approaches to the problems created by being at-risk and to possible courses of action.

Attitude to Health↗
PubMed1979

Genetic counseling--the postcounseling period: I. Parents' perceptions of uncertainty.

To investigate how parents who have had genetic counseling perceive the problems created by being at risk, transcripts of open-ended, semistructured follow-up interviews with 53 counselees were analyzed qualitatively. Rate information, though recalled accurately by parents considering further childbearing, was discounted as impersonal, and subjects overwhelmingly perceived the chance of recurrence in binary form -- it either will or will not happen. By processing rates this way, they simplified probabilistic information and shifted their focus to the implications of being at risk and the potential impact of that which might or might not occur. The many uncertainties they faced, the "consequences" of being at risk that parents felt had to be resolved during the decision-making process, fell into 3 major categories: uncertainty that arose because of the ambiguous impact and meaning of having an affected child; uncertainty about how to make a choice and how others would view it, the burden of decision-making; and uncertainty about their ability to fulfill their roles as parents. These issues were perceived as part of the problem to be resolved and were consolidated into "scenarios" in which the parents "tried out the worst." This analysis of counselees' perceptions of the problems created by being at genetic risk suggests that parents may process the disparate facts of their situation in common ways that emphasize their uncertainty, and it indicates that how parents perceive factual information may be more important in orienting their deliberations than what these facts (diagnosis, prognosis, risks) actually are.

Decision Making↗
PubMed1979

Genetic counseling -- the postcounseling period: II. Making reproductive choices.

Qualitative analysis of transcripts of follow-up interviews with 53 parents who had had genetic counseling was undertaken to characterize the process by which childbearing decisions were made and to determine how counselees resolved the problems created by being at risk. Although specific issues to be resolved varied with a parent's perception of his or her situation, all those who considered having subsequent children attempted to limit the uncertainties they faced and to neutralize those consequences perceived as most problematic. To do so, counselees uniformly inferred from factual information and experiences available to them how they could manage the possible consequences of taking a chance. Factors influencing a parent's ability to make a clear decision included the presence of a previous normal child, the diffusion of decision-making responsibility to others, and recognition that one had already managed the worst. When these "facts" could not be processed to provide a sense of coping, parents either decided against reproduction and took appropriate action or made a "non-decision" about reproduction by choosing to leave conception to chance. These various tactics allowed parents to create a "least-lose" option in terms of their child-bearing choices. This analysis of how parents make reproductive decisions, along with previous findings, suggests that being at risk both creates common problems and elicits common responses from counselees. Moreover, it highlights the importance of recognizing parents' perceptions of their situation to understand how their deliberations are structured and how factual information influences their ultimate choices.

Decision Making↗
PubMed1979

Stage of palate closure as one indication of "liability" to cleft palate.

A new inbred mouse strain, SW/Fr, developed from a random-bred SW stock has a 6% incidence of spontaneous cleft palate without cleft lip. SW/Fr mice close their palates comparatively late in development. After cortisone treatment, the mean of the distribution (mean time to reach palate stage 5) is shifted towards later gestational ages. There is no change in the variance of the distribution. These data lend further support to the hypothesis that cleft palate in mice may fit a model where a continuous distribution is separated into discontinuous parts by a developmental threshold, and that time of palate closure is an important component of liability to cleft palate.

Animals↗
PubMed1979

Genetic independence of the embryonic reactivity difference to cortisone- and 6-aminonicotinamide-induced cleft palate in the mouse.

The A/J strain of mice is more reactive than C57BL/6J to both cortisone- and 6-aminonicotinamide-induced cleft palate. A breeding study was set up to determine the genetic control of the differences in embryonic reactivity between the two strains to the two teratogens. In this paper the test for possible association between the two response traits is presented. In the second-backcross generation of embryos where segregation of the two traits could be studied no association was found. Therefore, any embryonic genes making major contributions to differences in reactivity between the two strains are not the same for the two teratogens.

6-Aminonicotinamide↗
PubMed1978

47,X,i(Xq),Y karyotype in Klinefelter's syndrome.

This is a case report of 47,X,i(Xq),Y in a 24-year-old infertile male with Klinefelter's syndrome. C staining indicated that this isochromosome X had a single small centromere. BUdR incorporation revealed the isochromosome X to be late replicating.

Azure Stains↗
PubMed1978

Genetics and Medicine: an evolving relationship.

The rapid expansion of knowledge in human and medical genetics has revealed at least 6 percent average heterozygosity per structural gene locus, in excess of 2300 Mendelian (single gene) variants and several hundred chromosomal variants in man. This means that with the exception of monozygous twins, no two individuals are alike in their phenotype. Therefore, each person has a relative state of health, and genetic factors contribute significantly to disease. The ubiquity of genetic diversity requires the development of services for genetic screening, diagnosis, and counseling to prevent and treat a major portion of disease in modern society. Specific programs in Quebec and Canada illustrate how individuals and populations can be served by such services. Better education of citizens and health professionals in human genetics is essential for the further improvement of genetics services in society.

Blood Chemical Analysis↗
PubMed1978

Genetic aspects of the BOR syndrome--branchial fistulas, ear pits, hearing loss, and renal anomalies.

A pedigree of branchio-oto-renal dysplasia (the BOR syndrome) is reported, including the documentation by serial audiometric studies of the onset and rapid progression of hearing loss in the twin sister of an affected child. The literature on this syndrome is analyzed to derive some figures for use in genetic counseling of such families. Branchio-oto-renal dysplasia is an autosomal dominant disorder in which affected individuals may have preauricular pits, lachrymal duct stenosis, hearing loss, branchial fistulas or cysts, structural defects of the outer, middle, and inner ear, and renal anomalies, which may range from mild hypoplasia to complete absence. Not all features of the syndrome are expressed in all carriers of the gene, but few carriers lack all the features, and the pits, branchial clefts, and hearing loss, are frequently expressed. Those offspring of affected persons who have pits or fistulas are likely (about 80%) to have hearing loss of varying degrees of severity. A minority of heterozygotes (about 7%) may have hearing loss without pits or fistulas. The risk of severe renal malformation is probably fairly low. Whether families that show dominant inheritance of pits, clefts, and deafness without renal anomalies represent variants of the BOR syndrome or a separate entity (the BO syndrome), is still not clear. At present, any individual with preauricular pits and branchial clefts deserves both otologic and renal investigation.

Abnormalities, Multiple↗
PubMed1978

Early changes in the mouse neuroepithelium preceding exencephaly induced by hypervitaminosis A.

Excess vitamin A orally administered to pregnant mice during neurulation causes most of the embryos to become exencephalic. The study presents light and electron microscopic observations that trace the origin and course of the early cellular and tissue alterations associated with the malformation. The main effects of the teratogen are seen in the neuroepithelial cells of the cephalic region of the presumptive nervous system. The degree to which each embryo is malformed varies but no matter how extensive the abnormalities in each embryo, the neuroepithelium is always affected and the lesions are similar. Mesodermal abnormalities appear only in the most seriously affected embryos. With the electron microscope, changes are apparent in the neuroepithelial cells within a few hours after maternal treatment. These changes include the formation of abnormally shaped nuclei with swollen nuclear envelopes, dilation of the rough endoplasmic reticulum, and formation of cytoplasmic inclusions that contain DNA and/or RNA. The inclusions are thought to arise as an autophagocytic response of the cells to the sub-lethal injury induced by the teratogen. In addition, a number of cells are more severely affected and degenerate. Light microscopic examination of serial sections reveals that by 20 hours after treatment, the neuroepithelium becomes disorganized: the cells are round and misaligned and intercellular connections are lost. We postulate that the early cellular alterations lead to a disruption of the architecture of the early neuroepithelium so that the neural folds fail to meet and close. The tissue may survive the initial insult, but continues to grow in the everted manner characteristic of exencephaly.

Animals↗
PubMed1978

Inidcations for prenatal diagnosis in relatives of patients with neural tube defects.

We have reviewed the family histories of children with neural tube defects to determine which relatives are at sufficient risk to be offered amniocentesis for prenatal diagnosis. The recurrence risks for sibs was 6%; therefore, women with one affected child should be made aware of the availability of this test for monitoring subsequent pregnancies. The empiric recurrence risks for various groups of second and third degree relative exceeds 1% only for mothers' sisters' children. The lower values for the other groups may reflect either true biologic differences of reporting biases. Unit the matter is clarified, all sibs of affected children and all sibs of the parents of affected children should be informed of the availability of amniocentesis for monitoring their (or their spouse's) pregnancies.

Amniocentesis↗