Angiotensin II receptors in human myocardium are present in relatively low numbers, and AT2 is the predominant subtype. A significant loss of angiotensin II receptors occurs in end stage but not in moderate heart failure. The loss of receptors affects both subtypes to a comparable degree. The data suggest that the decrease in receptor density is due to a decrease in steady-state mRNA abundance.

Between 1963 and 1990, Austria had iodized salt prophylaxis of endemic goitre with 10 mg KI (7.5 mg I) per kg. This was obviously insufficient, as urinary iodine excretion ranged from 42 to 78 microg I per g of creatinine and goitre in adults remained in the endemic range of 15%-30%. Therefore salt iodization was doubled in 1990. The aim of this study was to assess the annual incidence of different types of hyperthyroidism (HT) before and after this increase in salt iodization. The incidence of HT was recorded in 14 nuclear medicine centres from 1987 to 1995. In five additional centres data were available from 1992 onwards. Data prior to 1992 were documented retrospectively, while those after 1992 were recorded prospectively. The 14 centres drew patients from an area with a population of approximately 4.23 million while all 19 institutes were estimated to cover an area with a population of 5.4 million (the total population of Austria is 7.86 million). A total of 414232 persons were examined for the first time in the participating centres. HT and the type of HT were defined by clinical examination, serum TSH, thyroid hormone levels in blood, ultrasonography, scintigraphy and serum autoantibody titres. HT was classified into immunogenic HT (Graves' or Basedow's disease, GD) and HT with intrinsic thyroid autonomy (uni-, multinodular or disseminated Plummers' disease, PD). HT was also divided into overt (o) or subclinical (sc) disease. The following data were calculated: annual incidence per 100000 and the relative risk (RR) for HT with 95% confidence intervals (CI). In addition, linear trends were calculated for each type of HT by means of logistic regressions. In the 19 centres a total of 47834 patients with HT were registered from 1987 to 1995. PD accounted for 75% of all cases of HT and GD for 19%, while other types of HT were present in 6%. From 1987 to 1989 (time period T0), the annual incidence of oPD was 30.5 (95% CI 29.6-31.5) per 100000. The RR compared to the baseline period T0 was highest in 1992 (1.37; 1.3-1.45) and decreased to 1.17 (1.1-1.24) in 1995. The annual incidence of scPD in T0 was 27.4 (26.5-28.3) per 100000. The RR was highest in 1991 (1.64; 1.56-1.73) and was 1.60 (1. 51-1.69) in 1995. In oPD and scPD a higher RR was observed in persons older than 50 years of age, particularly in men. The incidence of oGD in T0 was 10.4 (9.8-10.9) per 100000; the maximum RR increased to 2.19 (2.01-2.38) in 1993 and decreased to 1.95 (1.78-2.13) in 1995. The incidence of scGD was 1.9 (1.6-2.1) in T0. The maximum RR was observed in 1994 (2.47; 2.04-3.0) and it was still 2.26 (1.85-2.77) in 1995. The increased incidence of oGD and scGD was evenly distributed in all ages and both sexes. The time course of different types of HT following the increase in salt iodization could be divided into two phases: an increase in the incidences of HT with peaks after 1-4 years and a subsequent decrease, the only exception being scGD. The effect was more pronounced in GD than in PD. PD showed an age and gender dependency over ...

The precise quantification of rare mRNA copies from intronless genes by reverse transcription polymerase chain reaction (RT-PCR)

To investigate the regulation of the angiotensin receptor type 1 (AT1) in different organs in cardiac volume overload, we measured AT1 mRNA content in the atria, left and right ventricle, kidney and liver of rats with an aortocaval shunt, produced by infrarenal aortocaval puncture 4 weeks earlier. For angiotensin receptor mRNA quantitation a novel quantitative PCR procedure based on liquid phase hybridization was used that allowed the determination of absolute AT1 mRNA copy numbers and its comparison in different organs. Glyceraldehydephosphate dehydrogenase (GAPDH) mRNA was measured by RT-PCR to control externally equal mRNA content and quality of RNA extraction in shunt animals and controls. Heart weight was increased in the shunt animals, with the greatest increase in the atria. Blood pressure, plasma renin activity, plasma angiotensin I and II and aldosterone concentrations were not significantly altered. The AT1 mRNA content was significantly increased in the atria (shunt: 1167 +/- 350 copies AT1 mRNA/ng RNA vs controls: 803 +/- 240; p < 0.05). No change was found in the right or left ventricle, in the kidney and liver. The findings document that atrial hypertrophy in cardiac volume overload parallel with a significant increase in atrial AT1 mRNA content.

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The number of atrial angiotensin II binding sites is reduced in end-stage human heart failure. The goals of our study were the development of a quantitative polymerase chain reaction for angiotensin II receptor type 1 mRNA to determine the angiotensin receptor type 1 (AT1) mRNA content in the atria of patients with end-stage heart failure. We established a quantitative PCR based on coamplification of AT1 wild-type and an internal standard in the same PCR, followed by liquid-phase hybridization of PCR products in microtiter plates and quantitation by ELISA. Glyceraldehyde phosphate dehydrogenase mRNA in the same samples was used to relate the AT1 mRNA content to a stably expressed reference gene. Atrial samples from 11 patients with end-stage heart failure obtained at cardiac transplantation were compared with atrial samples from 11 patients with normal cardiac function undergoing routine cardiac surgery. A PCR/ELISA system with a variance of about 6% after reverse transcription and a linear measuring range was established. In the samples from 11 patients with end-stage heart failure a 58% decrease in AT1 mRNA content was found in comparison with 11 controls (heart failure: 185,680 +/- 196,912 AT1 mRNA copies/microgram RNA, controls: 440,555 +/- 268,456, P < 0.02). When AT1 mRNA content was related to glyceraldehyde phosphate dehydrogenase mRNA, a 65% decrease was detected (AT1/glyceraldehyde phosphate dehydrogenase: heart failure: 4.84 +/- 5.18; controls: 13.74 +/- 7.77; P < 0.005). Standardization of PCR resulting in a low coefficient of variance, high reproducibility, and large sample capacity is possible using optimal internal standardization and the liquid-phase hybridization/ELISA system for detection. The optimized PCR procedure indicated downregulation of atrial AT1 in end-stage human heart failure, suggesting a reduced capacity of the atria to respond to angiotensin II stimulation in end-stage heart failure.

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