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.

     

Alcohol consumption and NHMRC guidelines: has the message got out,are people conforming and are they aware that alcohol causes cancer?

Objective: To examine self‐reported alcohol consumption and relationships between consumption, awareness of the 2009 NHMRC guidelines of no more than two standard drinks per day, drinking in excess of the guideline threshold and perceptions of alcohol as a risk factor for cancer. Methods: Questions were included in annual, cross‐sectional surveys of approximately 2,700 South Australians aged 18 years and over from 2004 to 2012. Consumption data for 2011 and 2012 were merged for the majority of analyses. Results: In 2011 and 2012, 21.6% of adults drank in excess of the guideline threshold (33.0% males; 10.7% females). While 53.5% correctly identified the NHMRC consumption threshold for women, only 20.3% did so for men (39.0% nominated a higher amount). A large minority said they did not know the consumption threshold for women (39.2%) or men (40.4%). In 2012, only 36.6% saw alcohol as an important risk factor for cancer. Important predictors of excess consumption for men were: higher household income; and not perceiving alcohol as an important risk factor for cancer. Predictors for women were similar but the role of household income was even more prominent. Conclusions: Men were nearly three times as likely to drink in excess of the guidelines as women. The majority of the population did not see an important link between alcohol and cancer. Awareness of the latest NHMRC guidelines consumption threshold is still low, particularly for men. Implications: A strategy to raise awareness of the NHMRC guidelines and the link between alcohol and cancer is warranted.     

Vascular stiffness is related to superoxide generation in the vessel wall

OBJECTIVES: Oxidative stress causes endothelial dysfunction and plays a major role in the pathogenesis of cardiovascular disease. Increased vascular stiffness is an intermediate phenotype in the development of cardiovascular disease. We hypothesized that vascular stiffness is partially determined by oxidative stress. METHODS: We examined 163 participants out of whom 80 had coronary artery disease. Vascular stiffness was assessed by pulse wave analysis, pulse wave velocity and measurement of aortic compliance by cardiac MRI. Circulating markers of oxidative stress and vascular superoxide generation in saphenous vein were measured. RESULTS: After adjustment for age, sex, BMI, heart rate, blood pressure and lipids only carotid-femoral pulse wave velocity and aortic compliance were different between patients and control group. Aortic compliance was reduced (11.4 +/- 6.3 vs. 13.9 +/- 7.3 ml x 10(-3) per mmHg; P = 0.035) and vascular superoxide generation increased (1.01 +/- 0.45 vs. 0.76 +/- 0.44 nmol/mg per min; P = 0.035) in patients with coronary artery disease compared with those without. In a multiple stepwise regression analysis, aortic compliance was determined by age (P < 0.001) and vascular superoxide production (P = 0.033). CYBA C242T and NOS3 G894T polymorphisms had additive effects on vascular superoxide generation (P = 0.026) and xanthine oxidase activity was increased in patients with CAD (P = 0.043). Genetic factors (P = 0.033) and xanthine oxidase activity (P < 0.001) were also related to aortic compliance. CONCLUSION: By measuring vascular superoxide generation and aortic compliance using cardiac MRI, we demonstrated a functional relationship between oxidative stress and vascular stiffness. Patients identified with high levels of vascular stiffness are most likely to benefit from strategies to reduce vascular oxidative stress.     

Same-day <Superscript>90</Superscript>Y radioembolization: implementing a new treatment paradigm

Purpose

To assess the feasibility of conducting pretreatment mesenteric angiography, coil embolization, ^99mTc macroaggregated albumin (^99mTc-MAA) scintigraphy, and ⁹⁰Y radioembolization treatment in a single, same-day, combined outpatient encounter.

Methods

This was a retrospective study of 78 patients treated during the period 2008 – 2015 who were managed in a single outpatient encounter under the guidance of the Interventional Radiology Department and The Nuclear Medicine Department. Pretreatment planning was performed by reviewing baseline imaging and estimated perfused liver volume bearing the tumor. The region of interest was estimated using 3-D software; this value was used for dosimetry planning. Maximum lung shunting fractions of 10 % for hepatocellular carcinoma and 5 % for liver metastases were assumed. Subsequently, hepatic angiography and ^99mTc-MAA scintigraphy were performed followed by ⁹⁰Y treatment in one outpatient encounter. Total in-room procedure time was recorded.

Results

All patients underwent same-day angiography, ^99mTc-MAA scintigraphy and ⁹⁰Y radioembolization. Of the 78 patients, 16 received multiple segmental treatments to both lobes, 44 received treatment to the right lobe, and 18 received treatment to the left lobe. The median dose was 106 Gy. The median number of ⁹⁰Y vials needed was two (range one to six). The median in-room time was 160 min (75 – 250 min). The residential status of the patients was as follows, 18 % (14/78) were local residents, 55 % (43/78) traveled from outside the city limits, 18 % (14/78) were from out-of-state, and 9 % (7/78) were resident abroad. Of the 78 patients, 61 (77 %) had hepatocellular carcinoma, and 17 (22 %) had liver metastases. The median lung dose was 3.5 Gy.

Conclusion

This study demonstrated the feasibility of same-day ⁹⁰Y evaluation and treatment while maintaining the principles of safe and effective ⁹⁰Y infusion including tumoricidal dosimetry (lobar, segmentectomy), minimization of nontarget flow, and minimization of lung dose. This paradigm translates into expeditious cancer care and significant cost savings.