title: The Effect of Myostatin-antagonist4 on a Severe Muscle Burn Injury

authors: Laurenson, Rachel Marie

subjects: murine muscle burn injury model

abstract: Myostatin is a growth and differentiation factor which belongs to the transforming growth factor-beta superfamily of genes. Mutations or deletions in the myostatin gene leads to the heavy muscling phenotype seen in various cattle breeds, including Belgian Blue and Peidmontese, and also in myostatin knockout mice. More recently, a human child with the heavy muscling phenotype was also found to carry a mutation in the myostatin gene. Conversely, increased expression of myostatin has been linked to various muscle wasting conditions induced by ageing or disease. Myostatin is therefore regarded as a strong inhibitor of muscle growth. In addition, myostatin has also been shown to control satellite cell activation post-natally, and is therefore considered a potent negative regulator of muscle regeneration and repair.

The ability to block myostatin function has enormous potential in the treatment of muscle injuries and various muscle wasting conditions. The Functional Muscle Genomics group at AgResearch Ltd. have recently developed several myostatin antagonists, produced by truncating the biologically active mature myostatin sequence. The following thesis describes the first in vivo study using the myostatin antagonist, Mstn-ant4, where its effect on wound healing was evaluated using a murine muscle burn injury model. Some promising results that Mstn-ant4 could improve muscle wound healing after a severe burn injury were obtained. Specifically, Mstn-ant4-treated mice recovered from the burn-induced loss of body weight earlier than the saline-treated mice. Mighty gene expression,which is a downstream target of myostatin and is involved in muscle hypertrophy, was also significantly higher in the burnt muscles of mice treated with Mstn-ant4 compared to saline-treated mice. In addition, histochemical analysis indicated that administration of Mstn-ant4 may have been terminated too early during the in vivo trial, as reflected by the sudden decrease in centrally formed nuclei in the burnt muscles of Mstn-ant4-treated mice at day 14, with the last subcutaneous injection of Mstn-ant4 occurring at day 15.

Although no other statistically significant results were obtained by histology, immunocytochemistry or gene expression analysis to support these results, it would be difficult to conclude that significant results could not be generated when the antagonist was used under optimised conditions. That is, further studies into the administration schedule of the antagonist need to be undertaken, particularly with regard to the frequency of administration and duration of treatment. Overall, Mstn-ant4 has significant potential to improve wound healing following a severe muscle burn injury.

text: The Effect of Myostatin-antagonist4 on a Severe Muscle Burn Injury Myostatin is a growth and differentiation factor which belongs to the transforming growth factor-beta superfamily of genes. Mutations or deletions in the myostatin gene leads to the heavy muscling phenotype seen in various cattle breeds, including Belgian Blue and Peidmontese, and also in myostatin knockout mice. More recently, a human child with the heavy muscling phenotype was also found to carry a mutation in the myostatin gene. Conversely, increased expression of myostatin has been linked to various muscle wasting conditions induced by ageing or disease. Myostatin is therefore regarded as a strong inhibitor of muscle growth. In addition, myostatin has also been shown to control satellite cell activation post-natally, and is therefore considered a potent negative regulator of muscle regeneration and repair.

The ability to block myostatin function has enormous potential in the treatment of muscle injuries and various muscle wasting conditions. The Functional Muscle Genomics group at AgResearch Ltd. have recently developed several myostatin antagonists, produced by truncating the biologically active mature myostatin sequence. The following thesis describes the first in vivo study using the myostatin antagonist, Mstn-ant4, where its effect on wound healing was evaluated using a murine muscle burn injury model. Some promising results that Mstn-ant4 could improve muscle wound healing after a severe burn injury were obtained. Specifically, Mstn-ant4-treated mice recovered from the burn-induced loss of body weight earlier than the saline-treated mice. Mighty gene expression,which is a downstream target of myostatin and is involved in muscle hypertrophy, was also significantly higher in the burnt muscles of mice treated with Mstn-ant4 compared to saline-treated mice. In addition, histochemical analysis indicated that administration of Mstn-ant4 may have been terminated too early during the in vivo trial, as reflected by the sudden decrease in centrally formed nuclei in the burnt muscles of Mstn-ant4-treated mice at day 14, with the last subcutaneous injection of Mstn-ant4 occurring at day 15.

Although no other statistically significant results were obtained by histology, immunocytochemistry or gene expression analysis to support these results, it would be difficult to conclude that significant results could not be generated when the antagonist was used under optimised conditions. That is, further studies into the administration schedule of the antagonist need to be undertaken, particularly with regard to the frequency of administration and duration of treatment. Overall, Mstn-ant4 has significant potential to improve wound healing following a severe muscle burn injury.

year: 2009

title: Delayed pasture germination allows improved rigid ryegrass (Lolium rigidum) control through grazing and broad-spectrum herbicide application

authors: Doole, Graeme J.

subjects: bioeconomic modelling

abstract: Eastern star clover (Trifolium dasyurum C. Presl.) is a new pasture legume developed for use in short phases between extended cropping sequences in Western Australian dryland agriculture. Its delayed germination provides an opportunity to obtain almost complete control of the highly-competitive crop weed rigid ryegrass (Lolium rigidum Gaudin) through non-selective herbicide application and/or grazing. Given the recent development of a commercial cultivar of eastern star clover (cv. AGWEST® Sothis), a complex simulation model is used to evaluate its potential profitability relative to continuous-cropping and rotations employing a popular pasture, French serradella (Ornithopus sativus Brot. cv. Cadiz). The profitability of those sequences containing eastern star clover is robust to high initial ryegrass populations and increasing severity of herbicide resistance. Moreover, the weed control benefits accruing to this pasture's delayed germination are of sufficient magnitude to offset the low establishment cost and higher biomass production of French serradella. This highlights the value of eastern star clover to producers in the Western Australian wheatbelt and offers an additional trait that plant breeders and selectors can exploit when seeking to expand weed control options in land-use sequences.

text: Delayed pasture germination allows improved rigid ryegrass (Lolium rigidum) control through grazing and broad-spectrum herbicide application Eastern star clover (Trifolium dasyurum C. Presl.) is a new pasture legume developed for use in short phases between extended cropping sequences in Western Australian dryland agriculture. Its delayed germination provides an opportunity to obtain almost complete control of the highly-competitive crop weed rigid ryegrass (Lolium rigidum Gaudin) through non-selective herbicide application and/or grazing. Given the recent development of a commercial cultivar of eastern star clover (cv. AGWEST® Sothis), a complex simulation model is used to evaluate its potential profitability relative to continuous-cropping and rotations employing a popular pasture, French serradella (Ornithopus sativus Brot. cv. Cadiz). The profitability of those sequences containing eastern star clover is robust to high initial ryegrass populations and increasing severity of herbicide resistance. Moreover, the weed control benefits accruing to this pasture's delayed germination are of sufficient magnitude to offset the low establishment cost and higher biomass production of French serradella. This highlights the value of eastern star clover to producers in the Western Australian wheatbelt and offers an additional trait that plant breeders and selectors can exploit when seeking to expand weed control options in land-use sequences.

year: 2010

title: A Maori and Psychology Research Unit

authors: Nikora, Linda Waimarie

subjects: Maori

abstract: Little psychological information and few applications have been informed by Maori centred research. The psychological research base available to support prevention or change strategies aimed at Maori is almost non-existent. Most information and applications are imported from outside of Aotearoa/New Zealand and are seldom subjected to vetting procedures to ensure adequacy and appropriateness. Even though numbers have changed slightly in the last 10 years, there are still too few Maori in the professional ranks of psychology, both as practitioners, teachers and researchers. More of everything is needed, and it was needed yesterday. At the University of Waikato, staff of the Psychology Department have recognised the need to support positive changes to rectify that situation described above.

This paper describes the fledgling development of a Maori and Psychology Research Unit and how it is intended to promote Maori centred-research, Maori-partnership research, and the scholarly development of Maori professionals. The first section deals with issues and challenges the MPRU expects to face in its development and is written by the first author. The second section describes the nature of learning and support that the MPRU will afford to a new generation of Maori researchers and scholars within the discipline of psychology. This section is written by the second author.

text: A Maori and Psychology Research Unit Little psychological information and few applications have been informed by Maori centred research. The psychological research base available to support prevention or change strategies aimed at Maori is almost non-existent. Most information and applications are imported from outside of Aotearoa/New Zealand and are seldom subjected to vetting procedures to ensure adequacy and appropriateness. Even though numbers have changed slightly in the last 10 years, there are still too few Maori in the professional ranks of psychology, both as practitioners, teachers and researchers. More of everything is needed, and it was needed yesterday. At the University of Waikato, staff of the Psychology Department have recognised the need to support positive changes to rectify that situation described above.

This paper describes the fledgling development of a Maori and Psychology Research Unit and how it is intended to promote Maori centred-research, Maori-partnership research, and the scholarly development of Maori professionals. The first section deals with issues and challenges the MPRU expects to face in its development and is written by the first author. The second section describes the nature of learning and support that the MPRU will afford to a new generation of Maori researchers and scholars within the discipline of psychology. This section is written by the second author.

year: 1998-07-01