A transgenic mouse bearing an antisense construct of regulatory subunit type 1A of protein kinase A develops endocrine and other tumours: comparison with Carney complex and other PRKAR1A induced lesions

Background: Inactivation of the human type Iα regulatory subunit (RIα) of cyclic AMP dependent protein kinase (PKA) (PRKAR1A) leads to altered kinase activity, primary pigmented nodular adrenocortical disease (PPNAD), and sporadic adrenal and other tumours.

Methods and results: A transgenic mouse carrying an antisense transgene for Prkar1a exon 2 (X2AS) under the control of a tetracycline responsive promoter (the Tg(Prkar1a*x2as)1Stra, Tg(tTAhCMV)3Uh or tTA/X2AS line) developed thyroid follicular hyperplasia and adenomas, adrenocortical hyperplasia and other features reminiscent of PPNAD, including late onset weight gain, visceral adiposity, and non-dexamethasone suppressible hypercorticosteronaemia, with histiocytic, epithelial hyperplasias, lymphomas, and other mesenchymal tumours. These lesions were associated with allelic losses of the mouse chromosome 11 Prkar1a locus, an increase in total type II PKA activity, and higher RIIß protein levels; the latter biochemical and protein changes were also documented in Carney complex tumours associated with PRKAR1A inactivating mutations and chromosome 17 PRKAR1A locus changes.

Conclusion: We conclude that the tTA/X2AS mouse line with a downregulated Prkar1a gene replicates several of the findings in Carney complex patients and their affected tissues, supporting the role of RIα as a candidate tumour suppressor gene.

     

Flow cytometric analysis of R3327 rat prostate adenocarcinoma grown in vivo and in vitro

The Dunning R3327 transplantable prostate adenocarcinoma in the Copenhagen rat is an acceptable model for the human disease. The G-subline (a rapidly growing carcinoma) and the H-subline (a slow-growing, well-differentiated adenocarcinoma) represent the extremes of differentiation and growth rate of this tumor. Both sublines were found to have one population that was diploid and a second aneuploid population that was hyperdiploid in DNA content. The percentage of hyperdiploid cells was significantly higher in R3327-G tumors than in R3327-H tumors. The tumor cell population ratios were stable in vivo, but the in vitro culture conditions supported only cells with diploid DNA content following four to five subcultures. These predominantly diploid cultured cells, when injected into intact male rats, resulted in tumors that had both diploid and aneuploid cells.     

Down-regulation of regulatory subunit type 1A of protein kinase A leads to endocrine and other tumors

Mutations of the human type Ialpha regulatory subunit (RIalpha) of cyclic AMP-dependent protein kinase (PKA; PRKAR1A) lead to altered kinase activity, primary pigmented nodular adrenocortical disease, and tumors of the thyroid and other tissues. To bypass the early embryonic lethality of Prkar1a(-/-) mice, we established transgenic mice carrying an antisense transgene for Prkar1a exon 2 (X2AS) under the control of a tetracycline-responsive promoter. Down-regulation of Prkar1a by up to 70% was achieved in transgenic mouse tissues and embryonic fibroblasts, with concomitant changes in kinase activity and increased cell proliferation, respectively. Mice developed thyroid follicular hyperplasia and adenomas, adrenocortical hyperplasia, and other features reminiscent of primary pigmented nodular adrenocortical disease, histiocytic and epithelial hyperplasias, lymphomas, and other mesenchymal tumors. These were associated with allelic losses of the mouse chromosome 11 Prkar1a locus, an increase in total type II PKA activity, and higher RIIbeta protein levels. This mouse provides a novel, useful tool for the investigation of cyclic AMP, RIalpha, and PKA functions and confirms the critical role of Prkar1a in tumorigenesis in endocrine and other tissues.     

Monitoring and evaluation in the special care unit: the JCAHO ten-step process

Monitoring and evaluating the quality and appropriateness of patient care in the special care unit is the basis for quality assurance activities. To make the monitoring and evaluation process helpful, health care professionals in special care units must be involved in each step of the process. The focus must be on patient care, specifically on clinical aspects of care rather than on structural specifications or technical processes. In addition to assisting the special care unit to meet accreditation requirements, ongoing monitoring and evaluation assist that unit to assure high-quality care. Monitoring and evaluation activities also assist the special care unit manager in responding to demands of state and federal regulators by providing an objective assessment of the care provided to Medicare and Medicaid patients. These activities also can provide assistance in responding to concerns about lawsuits involving alleged negligence in provision of special care; and in meeting pressures from third-party payers to reduce costs associated with unnecessary treatment in special care units. This chapter describes how the ten-step monitoring and evaluation process can be used to help assure high-quality patient care in the special care unit.     

The quality assurance process in critical care education

The American Association of Critical-Care Nurses (AACN) has developed education standards for critical care nursing. These structure and process standards can be used as part of the Joint Commission on Accreditation of Healthcare Organizations' (JCAHO) ten-step process for monitoring and evaluating critical care education programs. This chapter discusses the application of the monitoring and evaluation process, based on education standards, for critical care education programs.     

Fluorouracil for the treatment of massive periretinal proliferation

A single intravitreal injection of fluorouracil was effective in the treatment of an experimental model of massive periretinal proliferation. When given with an intravitreal injection of 250,000 heterologous fibroblasts, fluorouracil decreased the rate of tractional retinal detachment from 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) at one week, and from 73.6% in controls (14 of 19 eyes) to 31.5% in treated animals (six of 19 eyes) after four weeks (P less than .05). Intraocular neovascularization was reduced from 52.6% in controls (ten of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after one week and 36.8% in controls (seven of 19 eyes) to 5.2% in treated animals (one of 19 eyes) after four weeks. When supplemented by repeated 10-mg subconjunctival injections of fluorouracil, or in combination with intravitreally administered indomethacin, this effect appeared to be enhanced. Intravitreal and subconjunctival injections of fluorouracil were well tolerated and may prove to be of significant value in the treatment of human disease.