title: Prolactin signalling in murine hair growth

authors: Craven, A.J.

abstract: Although prolactin has been shown to entrain hair growth cycles in seasonally responsive mammals, no comparable role has been identified in the age-dependent pelage replacement of rodents. Prolactin binds to dimerised membrane-associated prolactin receptors (PRLR) on target organs and initiates signalling via a number of intracellular pathways including the JAK-Stat5b pathway. The role of this pathway in murine hair growth was investigated by (i) PRLR gene disrupted mice, (ii) altered circulating prolactin profiles and (iii) impaired PRLR signal transduction with Stat5b gene-disrupted mice. 
The long (PRLR-L), and two short (PRLR-S2 and PRLR-S3) forms of the prolactin receptor were shown by RT-PCR to be expressed in the skin. These receptors were immunolocalised to the outer root sheath of the follicle as well as the epidermis and sebaceous gland. The first hair replacement cycle in PRLR gene-disrupted mice was advanced by 4 days in males and 2 weeks in females compared to wild type controls. Similarly, bromocriptine suppression of prolactin secretion advanced hair replacement by four days, which could be reversed by administration of exogenous prolactin at 18-22 days of age. In contrast, hair replacement in Stat5b-disrupted mice was delayed by two weeks. The duration of anagen, measured as the period of fibre elongation, did not differ between treated and control groups in any of these experiments. Pelage structure, fibre length and fibre diameter was not substantially altered. Pelage renewal across the body was slower during pregnancy and pseudopregnancy, and halted completely during lactation. Only after weaning was follicle reactivation resumed. As a key gestational and lactation hormone, prolactin is a likely candidate as a modulator of hair cycling at this time. An inverse relationship between PRLR-L mRNA and prolactin mRNA demonstrates the high level of prolactin signal regulation in the skin during reproduction. 
Hence, both reduced circulating prolactin levels and PRLR-deficiency results in a shorter telogen and hair renewal at a younger age. In contrast, when the signalling protein Stat5b is absent, follicle growth was retarded and new hair growth occurred later than in wild type mice. This could be explained by the altered pituitary feedback regulation of lactotrophs resulting in hyperprolactinemia in Stat5b-deficient mice. These results provide strong evidence that prolactin inhibits the activation of murine hair follicle growth.

text: Prolactin signalling in murine hair growth Although prolactin has been shown to entrain hair growth cycles in seasonally responsive mammals, no comparable role has been identified in the age-dependent pelage replacement of rodents. Prolactin binds to dimerised membrane-associated prolactin receptors (PRLR) on target organs and initiates signalling via a number of intracellular pathways including the JAK-Stat5b pathway. The role of this pathway in murine hair growth was investigated by (i) PRLR gene disrupted mice, (ii) altered circulating prolactin profiles and (iii) impaired PRLR signal transduction with Stat5b gene-disrupted mice. 
The long (PRLR-L), and two short (PRLR-S2 and PRLR-S3) forms of the prolactin receptor were shown by RT-PCR to be expressed in the skin. These receptors were immunolocalised to the outer root sheath of the follicle as well as the epidermis and sebaceous gland. The first hair replacement cycle in PRLR gene-disrupted mice was advanced by 4 days in males and 2 weeks in females compared to wild type controls. Similarly, bromocriptine suppression of prolactin secretion advanced hair replacement by four days, which could be reversed by administration of exogenous prolactin at 18-22 days of age. In contrast, hair replacement in Stat5b-disrupted mice was delayed by two weeks. The duration of anagen, measured as the period of fibre elongation, did not differ between treated and control groups in any of these experiments. Pelage structure, fibre length and fibre diameter was not substantially altered. Pelage renewal across the body was slower during pregnancy and pseudopregnancy, and halted completely during lactation. Only after weaning was follicle reactivation resumed. As a key gestational and lactation hormone, prolactin is a likely candidate as a modulator of hair cycling at this time. An inverse relationship between PRLR-L mRNA and prolactin mRNA demonstrates the high level of prolactin signal regulation in the skin during reproduction. 
Hence, both reduced circulating prolactin levels and PRLR-deficiency results in a shorter telogen and hair renewal at a younger age. In contrast, when the signalling protein Stat5b is absent, follicle growth was retarded and new hair growth occurred later than in wild type mice. This could be explained by the altered pituitary feedback regulation of lactotrophs resulting in hyperprolactinemia in Stat5b-deficient mice. These results provide strong evidence that prolactin inhibits the activation of murine hair follicle growth.

year: 2003

title: The Maintenance of Group Identity Through Social Networks in the Bay of Plenty Dutch Community

authors: Webster, Kaye Louise

subjects: Dutch

abstract: Abel Tasman, a Dutchman, was the first person to put New Zealand on European maps over three hundred years ago (in 1642) and today there are over twenty-eight thousand people living in New Zealand who identify themselves as Dutch and twenty-seven thousand people speaking the Dutch language.

Previous research has explored various aspects of Dutch migration, including migrant experiences, culture and language yet only de Bres (2004) compares the experiences of Dutch immigrants across time periods of their arrival. Cultural retention and maintenance has mainly been assessed via the use of the Dutch language rather than through other methods, such as Dutch customs and social networks. The main reason for this research is to compare the experiences and cultural identity of the three 'waves' of Dutch migrants, which has not been undertaken before.

This study interviewed six Dutch settler families living in the Bay of Plenty, from three time-periods (1950s; 1960s to 1980s; and 1990s to today) and across generations in order to compare their experiences and assess if and how they maintain their Dutch identity through their use of customs and social networks. Open-ended questionnaires and interview schedules were used to interview the sixteen participants. Content analysis was undertaken for the majority of the questionnaire and interview schedules. For the remaining questions that focused on social networks, the structural aspects of the social support for participants were measured in terms of the social network characteristics, size, density and multiplexity.

The study found an overall retention of Dutch identity across all time-periods for generation one (generation one refers to the migrating parents) with all families using the Dutch language within their own homes, yet only one family maintaining their Dutch identity through social networks and only one family maintaining their Dutch identity through the use of customs.

The second and third generation participants have little to no interest or involvement in the Dutch culture or community. One second generation participant considered herself Dutch-Kiwi, with the remaining second generation participants considering themselves New Zealanders. Only one person from the third generation participated and she identified herself as a Dutch-Kiwi. Overall, this study supports the perception of the 'invisible Dutch' however due to the small sample size it is impossible to make conclusive statements concerning the Bay of Plenty Dutch community.

There is a limited amount of research comparing the experiences of Dutch migrants and how their cultural identity is maintained through their social networks; therefore further research is required to fill this gap.

text: The Maintenance of Group Identity Through Social Networks in the Bay of Plenty Dutch Community Abel Tasman, a Dutchman, was the first person to put New Zealand on European maps over three hundred years ago (in 1642) and today there are over twenty-eight thousand people living in New Zealand who identify themselves as Dutch and twenty-seven thousand people speaking the Dutch language.

Previous research has explored various aspects of Dutch migration, including migrant experiences, culture and language yet only de Bres (2004) compares the experiences of Dutch immigrants across time periods of their arrival. Cultural retention and maintenance has mainly been assessed via the use of the Dutch language rather than through other methods, such as Dutch customs and social networks. The main reason for this research is to compare the experiences and cultural identity of the three 'waves' of Dutch migrants, which has not been undertaken before.

This study interviewed six Dutch settler families living in the Bay of Plenty, from three time-periods (1950s; 1960s to 1980s; and 1990s to today) and across generations in order to compare their experiences and assess if and how they maintain their Dutch identity through their use of customs and social networks. Open-ended questionnaires and interview schedules were used to interview the sixteen participants. Content analysis was undertaken for the majority of the questionnaire and interview schedules. For the remaining questions that focused on social networks, the structural aspects of the social support for participants were measured in terms of the social network characteristics, size, density and multiplexity.

The study found an overall retention of Dutch identity across all time-periods for generation one (generation one refers to the migrating parents) with all families using the Dutch language within their own homes, yet only one family maintaining their Dutch identity through social networks and only one family maintaining their Dutch identity through the use of customs.

The second and third generation participants have little to no interest or involvement in the Dutch culture or community. One second generation participant considered herself Dutch-Kiwi, with the remaining second generation participants considering themselves New Zealanders. Only one person from the third generation participated and she identified herself as a Dutch-Kiwi. Overall, this study supports the perception of the 'invisible Dutch' however due to the small sample size it is impossible to make conclusive statements concerning the Bay of Plenty Dutch community.

There is a limited amount of research comparing the experiences of Dutch migrants and how their cultural identity is maintained through their social networks; therefore further research is required to fill this gap.

year: 2007

title: The Unmet Legal, Social and Cultural Needs of Māori with Disabilities

authors: Hickey, Susan Jane

subjects: Māori

abstract: There is little work done in the area of indigenous disability identity issues and how they are recognised in domestic and international human rights laws. The discourse of disability has always been based on social constructionism and without it, there is no identity. I discuss its relevance to indigenous (Māori) with disabilities and how the multiplicitous nature of the identity of  other  has a particular impact when indigenous, gender and disability are all identified from marginalised groups. I also explore the impact of westernised thinking around impairment, in particular the models of disabilities on indigenous well-being. The issues of family (whānau), whakawhanaungatanga (family relationships), interdependence (community) and collectivity identities central to indigenous thinking are largely ignored by law and policy, yet central to indigenous identity. This ignorance in policy has led to the disparities that continue to remain for indigenous persons with disabilities, particularly those from within thematic identity groups.

text: The Unmet Legal, Social and Cultural Needs of Māori with Disabilities There is little work done in the area of indigenous disability identity issues and how they are recognised in domestic and international human rights laws. The discourse of disability has always been based on social constructionism and without it, there is no identity. I discuss its relevance to indigenous (Māori) with disabilities and how the multiplicitous nature of the identity of  other  has a particular impact when indigenous, gender and disability are all identified from marginalised groups. I also explore the impact of westernised thinking around impairment, in particular the models of disabilities on indigenous well-being. The issues of family (whānau), whakawhanaungatanga (family relationships), interdependence (community) and collectivity identities central to indigenous thinking are largely ignored by law and policy, yet central to indigenous identity. This ignorance in policy has led to the disparities that continue to remain for indigenous persons with disabilities, particularly those from within thematic identity groups.

year: 2008