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Biomedical subjects

K Daniels

Publications and source records attributed to K Daniels.

At least 19 recordsLinked to original sources
PubMed2006

Sperm donation: implications of Canada's Assisted Human Reproduction Act 2004 for recipients, donors, health professionals, and institutions.

BACKGROUND: On April 22, 2004, the Assisted Human Reproduction Act came into force, prohibiting the purchase of sperm or eggs from donors in Canada. In response to the concerns of medical professionals and some consumers that prohibiting payment would lead to a decline in the number of gamete donors, Health Canada commissioned research on altruistic donor recruitment and recruitment strategies. METHODS: Twenty-two studies of sperm donors were located and their findings reviewed. The studies spanned 23 years (1980-2003), were undertaken in a range of countries, and were chosen on the merit of their relevance to the development of recruitment strategies within a policy of altruistic sperm donation. Observations were derived from assessing and comparing the purposes, findings, and implications of the 22 studies. RESULTS: Payment for providing sperm was made in all but three studies, although participants in 15 studies indicated clearly that their motivations were primarily altruistic. Observations indicate that men who are more willing to be identified to offspring in the future share demographic characteristics, such as age and parental status, with those who are prepared to donate altruistically. These characteristics appear to be a factor in motivation to donate altruistically. CONCLUSION: The studies show that there are men who are prepared to donate sperm without financial payment. The findings suggest that a change is required in the culture of sperm donation, specifically the adoption of a new approach to donor recruitment.

Altruism↗
PubMed2005

Short communication: previous semen donors and their views regarding the sharing of information with offspring.

BACKGROUND: The UK government has decided to introduce, from 2005, rules that will allow donor-conceived persons to have access to identifying information concerning their donor. This has led to many concerns regarding future gamete donor recruitment. METHODS: Semen donors who had been recruited between 1988 and 2002 were invited to take part in a telephone interview. The interview sought these previous donors' views on issues associated with recruitment, attitudes regarding information sharing and views concerning the offspring. Responses regarding information sharing were compared with their views recorded at the time of recruitment. RESULTS: All 32 donors were recruited altruistically. Eighteen (56%) held the same views concerning the provision of identifying information as they did at the time of recruitment. Of those who had changed their views, eight (25%) expressed a willingness to be more open and four (12%) now wished to be anonymous having previously been unsure. Half of the donors would still have donated if they had been required to be identified to offspring, one-quarter would not have and one-quarter were undecided, although the majority of these said they may have donated under an open system. CONCLUSION: The study shows that it is possible to recruit identifiable donors at this clinic and this suggests that it may be possible for other clinics to do likewise.

Adolescent↗
PubMed2005

School-aged children of donor insemination: a study of parents' disclosure patterns.

BACKGROUND: A major concern in relation to donor insemination (DI) is whether children should be told about their genetic origins. This study compared the thoughts, feelings and experiences of DI parents who were inclined towards openness with those who were inclined towards non-disclosure. METHODS: Forty-six families with a 4- to 8-year-old DI-conceived child were interviewed about their decision, their reasons and subsequent concerns regarding disclosure. RESULTS: Thirty-nine percent of parents were inclined towards disclosure whilst the remaining 61% were not. The two main reasons for favouring disclosure were to avoid accidental discovery and a desire for openness. Non-disclosing parents felt that there was no reason to tell and wished to protect family members. The children who had been told reacted with either curiosity or disinterest. CONCLUSIONS: In spite of donor anonymity, parents who were intending to tell their child in the future had optimistic expectations of their child's reaction. Parents who had already told their child generally described the telling experience as a positive one.

Adult↗
PubMed2005

Semen providers and their three families.

BACKGROUND: In 1985 the Swedish government introduced legislation that required all semen providers to furnish identifying information on themselves which would then be made available to their biological/provider offspring when they are deemed to have 'sufficient maturity'. The purpose of the legislation was to protect the child's rights and needs. The aim of this paper is to examine the degree to which semen providers have considered the implications of their decision to donate upon their three families; their birth family, the family they form with their partner, and the recipient family. METHODS: Thirty semen providers from two Swedish clinics were sent self-completion questionnaires collecting both quantitative and qualitative information. The initial response rate was 100%. Questions requested demographic information; the degree to which semen providers had consulted with or advised their partners, family, existing offspring and acquaintances about their semen donation; views and attitudes of semen providers towards donor offspring, anonymity, information sharing, payments to semen providers, community acceptance of DI and semen providers, experience of donation, recruitment/screening procedures. RESULTS: Almost all respondents had told their partners that they were providing semen, however, a much smaller proportion had told their birth families. Almost two thirds of semen providers were positive or very positive about the prospect of meeting their offspring at some time in the future, with older men expressing more enthusiasm. CONCLUSIONS: The findings suggest that semen providers have only partially considered and addressed the full implications of having semen provider offspring. The age of semen providers could be influential in determining some attitudes and views.

Adult↗
PubMed2005

Is blood really thicker than water? Assisted reproduction and its impact on our thinking about family.

The traditional notion that a family is built around and based on blood or genetic ties is challenged when assisted human reproduction utilizing donor gametes is used. A focus on the family--in contrast to the individual--requires from medicine an extension of thinking in which a model that incorporates treating infertility and building a family becomes the norm. Such a model will require that attention is given to the psychological and social needs of the would-be parents, thus enabling them to approach their family building with confidence. This confidence is expected to carry through to their sharing with their offspring the nature of their family building and thus avoid the stigma that leads to secrecy. Research relating to dimensions of family building when donor insemination has been used is reviewed. The impact of professional attitudes, along with the policies adopted by governments concerning access to genetic information for offspring, significantly influences the families built with assistance of donor gametes or embryos. The evolution of professional thinking in this area is reviewed, along with the increasing involvement of governments.

Anxiety↗
PubMed2005

Regulation and reproductive choice: the New Zealand approach.

The Warnock Report has had a significant impact on regulatory developments in many jurisdictions including New Zealand. While New Zealand has adopted a different system than that in the United Kingdom the objectives are the same, namely to manage in a responsible way, the issues associated with regulation and reproductive choices.

Female↗
PubMed2004

Perceived risk from occupational stress: a survey of 15 European countries.

AIMS: To examine the ranking of workers in 15 European countries with respect to the extent that work is perceived to influence occupational stress. METHODS: International interviewer administered cross-sectional survey. Control variables included demographics, perceived job conditions, and job satisfaction. A sample of working adults (n = 11 054) from 15 European countries were studied. RESULTS: In three statistical models, the British sample ranked in the lower half of the distribution, where higher rankings indicated greater perceived risk of occupational stress. The Greek sample was ranked first in all models, and the Irish sample ranked last in all models. CONCLUSIONS: Since there is sociocultural variation in the perceived risk from occupational stress, it is possible that sociocultural factors influence the accuracy of national monitoring systems and the success of occupational health policy in this area.

Adult↗
PubMed2003

Recruitment and motivation of semen providers in Sweden.

BACKGROUND: Legislation in Sweden requires that semen providers are prepared to be identified to offspring (at maturity) should this be requested. This study presents views of semen providers in Sweden regarding factors associated with their recruitment and motivation. METHODS: All semen providers (n = 30) in two clinics in different parts of Sweden participated in a questionnaire survey and both quantitative and qualitative data are reported. RESULTS: While there were some important demographic differences between the two clinic populations, there was total agreement that the desire to assist infertile couples was the sole or main motivating factor in becoming a semen provider. Monetary reward was not reported by respondents to be an important motivator, although at least 50% of the providers in both clinics thought that payment should be made and reimbursement of expenses was reported as being important. Men responded to both advertising and personal experiences or contacts they had with infertile couples. The involvement and support of the semen provider's partner was regarded as important. CONCLUSIONS: Semen providers can be recruited within a system that requires them to be prepared to be identified to offspring in the future. The characteristics of such providers vary, but are typified by a strong desire to assist infertile couples.

Advertising↗
PubMed2001

The Child Abuse Potential Inventory and pregnancy outcome in expectant adolescent mothers.

OBJECTIVE: The study explores the prenatal Child Abuse Potential (pCAP) scores derived from the Child Abuse Potential Inventory administered to expectant adolescent mothers. The aim of the study was to assess the association of the pCAP scores with maternal negative prenatal behaviors, and evaluate the contribution of the pCAP scores to neonatal morbidity. METHOD: The pCAP scores, demographic data, and self-report on prenatal behaviors were obtained during the second half of the pregnancy in a sample of 45 poor single adolescent mothers. A pediatrician blind to the prenatal data reviewed the neonatal records to assess neonatal morbidity. Maternal prenatal records were reviewed for obstetric risk assessment by an obstetrician who was blind to the rest of the data. The relations among the pCAP scores, prenatal behaviors, and neonatal morbidity were analyzed. RESULTS: In the prenatal period, the pCAP scores were positively correlated with self-reported prenatal smoking and substance use. The multiple linear regression analysis showed that the pCAP scores significantly contributed to neonatal morbidity independently of obstetric risk factors. CONCLUSIONS: The Child Abuse Potential scores obtained during pregnancy in poor single adolescent mothers reflect domains of maternal functioning that are associated with negative prenatal behaviors and appear to be important for predicting neonatal morbidity. Further studies are warranted to validate the prenatal use of the Child Abuse Potential Inventory.

Adolescent↗
PubMed2001

The histone deacetylase genes HDA1 and RPD3 play distinct roles in regulation of high-frequency phenotypic switching in Candida albicans.

Five histone deacetylase genes (HDA1, RPD3, HOS1, HOS2, and HOS3) have been cloned from Candida albicans and characterized. Sequence analysis and comparison with 17 additional deacetylases resulted in a phylogenetic tree composed of three major groups. Transcription of the deacetylases HDA1 and RPD3 is down-regulated in the opaque phase of the white-opaque transition in strain WO-1. HOS3 is selectively transcribed as a 2.5-kb transcript in the white phase and as a less-abundant 2.3-kb transcript in the opaque phase. HDA1 and RPD3 were independently deleted in strain WO-1, and both switching between the white and opaque phases and the downstream regulation of phase-specific genes were analyzed. Deletion of HDA1 resulted in an increase in the frequency of switching from the white phase to the opaque phase, but had no effect on the frequency of switching from the opaque phase to the white phase. Deletion of RPD3 resulted in an increase in the frequency of switching in both directions. Deletion of HDA1 resulted in reduced white-phase-specific expression of the EFG1 3.2-kb transcript, but had no significant effect on white-phase-specific expression of WH11 or opaque-phase-specific expression of OP4, SAP1, and SAP3. Deletion of RPD3 resulted in reduced opaque-phase-specific expression of OP4, SAP1, and SAP3 and a slight reduction of white-phase-specific expression of WH11 and 3.2-kb EFG1. Deletion of neither HDA1 nor RPD3 affected the high level of white-phase expression and the low level of opaque-phase expression of the MADS box protein gene MCM1, which has been implicated in the regulation of opaque-phase-specific gene expression. In addition, there was no effect on the phase-regulated levels of expression of the other deacetylase genes. These results demonstrate that the two deacetylase genes HDA1 and RPD3 play distinct roles in the suppression of switching, that the two play distinct and selective roles in the regulation of phase-specific genes, and that the deacetylases are in turn regulated by switching.

Amino Acid Sequence↗
PubMed2001

Risk factors for frequent and severe hypoglycemia in type 1 diabetes.

OBJECTIVE: To determine the risk of frequent and severe hypoglycemia and the associated demographic and clinical risk factors. RESEARCH DESIGN AND METHODS: Demographic and diabetes self-management factors were measured in 415 subjects followed prospectively for 4-6.5 years of type 1 diabetes duration as participants in a population-based incident cohort. Blood samples were collected up to three times yearly to test glycosylated hemoglobin (GHb) levels. Reports of frequent (2-4 times/week) and severe (lost consciousness) hypoglycemia as well as other diabetes self-management data were collected by questionnaires. RESULTS: Frequent hypoglycemia was common (33 and 35% of participants reported this on the 4- and 6.5-year questionnaires, respectively), whereas severe hypoglycemia occurred much less often. Better glycemic control (odds ratio [OR] 1.3 per 2% decrease in GHb, 95% CI 1.1-1.5) and more frequent self-monitored blood glucose (1.5 per blood glucose check, 1.3-1.7) were independently related to frequent hypoglycemia. The association of frequent hypoglycemia with intensive insulin therapy increased with age. Better glycemic control (1.5 per 2% decrease in GHb, 1.2-2.0) and older age were related to severe hypoglycemic reactions. No sociodemographic factors other than age increased the risk of hypoglycemia. CONCLUSIONS: Frequent hypoglycemia was common in a population representing the full range of glycemic control in the community. Intensive insulin management and blood glucose monitoring independently predicted frequent but not severe hypoglycemia. This information may be useful for updating patients such that minor changes in diabetes management might decrease the daily burden of this condition while maintaining intensive insulin therapy.

Adolescent↗
PubMed2000

The internal phosphodiesterase RegA is essential for the suppression of lateral pseudopods during Dictyostelium chemotaxis.

Dictyostelium strains in which the gene encoding the cytoplasmic cAMP phosphodiesterase RegA is inactivated form small aggregates. This defect was corrected by introducing copies of the wild-type regA gene, indicating that the defect was solely the consequence of the loss of the phosphodiesterase. Using a computer-assisted motion analysis system, regA(-) mutant cells were found to show little sense of direction during aggregation. When labeled wild-type cells were followed in a field of aggregating regA(-) cells, they also failed to move in an orderly direction, indicating that signaling was impaired in mutant cell cultures. However, when labeled regA(-) cells were followed in a field of aggregating wild-type cells, they again failed to move in an orderly manner, primarily in the deduced fronts of waves, indicating that the chemotactic response was also impaired. Since wild-type cells must assess both the increasing spatial gradient and the increasing temporal gradient of cAMP in the front of a natural wave, the behavior of regA(-) cells was motion analyzed first in simulated temporal waves in the absence of spatial gradients and then was analyzed in spatial gradients in the absence of temporal waves. Our results demonstrate that RegA is involved neither in assessing the direction of a spatial gradient of cAMP nor in distinguishing between increasing and decreasing temporal gradients of cAMP. However, RegA is essential for specifically suppressing lateral pseudopod formation during the response to an increasing temporal gradient of cAMP, a necessary component of natural chemotaxis. We discuss the possibility that RegA functions in a network that regulates myosin phosphorylation by controlling internal cAMP levels, and, in support of that hypothesis, we demonstrate that myosin II does not localize in a normal manner to the cortex of regA(-) cells in an increasing temporal gradient of cAMP.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2000

Work, psychological well-being and performance.

Evidence is reviewed on work performance as a consequence of both psychological well-being and work stressors. There is evidence that some forms of psychological well-being are related to subsequent in-role performance, although the evidence for a causal influence of work stressors on job performance is much weaker. There is also evidence for relationships between some job stressors or well-being and organizational citizenship behaviours. In general, research conducted at the individual level, indicates only weak or provisional relationships. A small number of recent studies indicate stronger associations between average levels of well-being in an organization and organizational performance. It is concluded that more detailed and specific models of well-being and work performance need to be developed. These models need to be tested using methods that can more easily detect subtle variations in well-being and work performance.

Adaptation, Psychological↗
PubMed2000

Phenotypic switching in Candida glabrata involves phase-specific regulation of the metallothionein gene MT-II and the newly discovered hemolysin gene HLP.

Although Candida glabrata has emerged in recent years as a major fungal pathogen, there have been no reports demonstrating that it undergoes either the bud-hypha transition or high-frequency phenotypic switching, two developmental programs believed to contribute to the pathogenic success of other Candida species. Here it is demonstrated that C. glabrata undergoes reversible, high-frequency phenotypic switching between a white (Wh), light brown (LB), and dark brown (DB) colony phenotype discriminated on an indicator agar containing 1 mM CuSO(4). Switching regulates the transcript level of the MT-II metallothionein gene(s) and a newly discovered gene for a hemolysin-like protein, HLP. The relative MT-II transcript levels in Wh, LB, and DB cells grown in the presence of CuSO(4) are 1:27:81, and the relative transcript levels of HLP are 1:20:35. The relative MT-II and HLP transcript levels in cells grown in the absence of CuSO(4) are 1:20:30 and 1:20:25, respectively. In contrast, switching has little or no effect on the transcript levels of the genes MT-I, AMT-I, TRPI, HIS3, EPAI, and PDHI. Switching of C. glabrata is not associated with microevolutionary changes identified by the DNA fingerprinting probe Cg6 and does not involve tandem amplification of the MT-IIa gene, which has been shown to occur in response to elevated levels of copper. Finally, switching between Wh, LB, and DB occurred in all four clinical isolates examined in this study. As in Candida albicans, switching in C. glabrata may provide colonizing populations with phenotypic plasticity for rapid responses to the changing physiology of the host, antibiotic treatment, and the immune response, through the differential regulation of genes involved in pathogenesis. More importantly, because C. glabrata is haploid, a mutational analysis of switching is now feasible.

Amino Acid Sequence↗
PubMed2000

EFG1 null mutants of Candida albicans switch but cannot express the complete phenotype of white-phase budding cells.

The Candida albicans gene EFG1 encodes a putative trans-acting factor. In strain WO-1, which undergoes the white-opaque transition, EFG1 is transcribed as a 3.2-kb mRNA in white-phase cells and a less-abundant 2.2-kb mRNA in opaque-phase cells. cDNA sequencing and 5' rapid amplification of cDNA ends analysis demonstrate that the major difference in molecular mass of the two transcripts is due to different transcription start sites. EFG1 null mutants form opaque-phase colonies and express the opaque-phase cell phenotype at 25 degrees C. When shifted from 25 to 42 degrees C, mutant opaque-phase cells undergo phenotypic commitment to the white phase, which includes deactivation of the opaque-phase-specific gene OP4 and activation of the white-phase-specific gene WH11, as do wild-type opaque-phase cells. After the commitment event, EFG1 null mutant cells form daughter cells which have the smooth (pimpleless) surface of white-phase cells but the elongate morphology of opaque-phase cells. Taken together, these results demonstrate that EFG1 expression is not essential for the switch event per se, but is essential for a subset of phenotypic characteristics necessary for the full expression of the phenotype of white-phase cells. These results demonstrate that EFG1 is not the site of the switch event, but is, rather, downstream of the switch event.

5' Untranslated Regions↗
PubMed2000

Clathrin plays a novel role in the regulation of cell polarity, pseudopod formation, uropod stability and motility in Dictyostelium.

Although the traditional role of clathrin has been in vesicle trafficking and the internalization of receptors, a novel role in cytokinesis was recently revealed in an analysis of a clathrin-minus Dictyostelium mutant (chc(-)). chc(-) cells grown in suspension were demonstrated to be defective in assembling myosin II into a normal contractile ring. To test whether this defect reflected a more general one of cytoskeletal dysfunction, chc(-) cells were analyzed for cell polarity, pseudopod formation, uropod stability, cell locomotion, chemotaxis, cytoskeletal organization and vesicle movement. chc(-) cells crawled, chemotaxed, localized F-actin in pseudopods, organized their microtubule cytoskeleton in a relatively normal fashion and exhibited normal vesicle dynamics. Although chc(-) cells extended pseudopods from the anterior half of the cell with the same frequency as normal chc(+) cells, they extended pseudopods at twice the normal frequency from the posterior half of the cell. The uropods of chc(-) cells also exhibited spatial instability. These defects resulted in an increase in roundness, a reduction in polarity, a reduction in velocity, a dramatic increase in turning, a high frequency of 180 degrees direction reversals and a decrease in the efficiency of chemotaxis. All defects were reversed in a rescued strain. These results are the first to suggest a novel role for clathrin in cell polarity, pseudopod formation, uropod stability and locomotion. It is hypothesized that clathrin functions to suppress pseudopod formation and to stabilize the uropod in the posterior half of a crawling cell, two behavioral characteristics that are essential for the maintenance of cellular polarity, efficient locomotion and efficient chemotaxis.

Actins↗
PubMed2000

Effects of aging on efficiency of task switching in a variant of the trail making test.

The Trail Making Test (TMT; R. M. Reitan, 1958, 1992) is extensively used in research in neuropsychology and in aging, in part because it has been postulated to reflect executive processes, such as planning and switching. However, neurocognitive and individual-difference-based analyses of this test are complicated because of different spatial arrangements of targets, the use of letters only in Version B, and potential order effects when Version A is administered prior to Version B. The present article examines a variant of a TMT (called the Connections Test) that attempts to remedy these deficiencies. A structural equation model suggested that there were no direct effects of age on either the nonalternating or alternating versions of the Connections Test (analogous to TMT Versions A and B, respectively); rather, all age-related effects were mediated through effects on perceptual speed. Moreover, although the nonalternating and alternating versions were strongly related to one another, only the latter had significant independent relations with measures of higher order cognition.

Adolescent↗