Association of Trp64Arg beta 3-adrenergic-receptor gene polymorphism with essential hypertension in the Sardinian population

OBJECTIVE

To evaluate the possible association of three candidate gene polymorphisms with essential hypertension in the genetically homogeneous Sardinian population.

SUBJECTS AND METHODS

We studied 494 unrelated, nondiabetic subjects, 213 (43.2%) with essential hypertension. All subjects underwent a 75 g oral glucose tolerance test with determination of glycemia and insulinemia and serum lipids. The polymorphisms evaluated comprised Trp64Arg of the beta 3-adrenergic receptor, Gly40Ser of the glucagon receptor gene and the insertion/deletion polymorphism of the angiotensin converting enzyme (ACE) gene.

RESULTS

Among the overall population studied, 48 (9.7%) were heterozygous carriers of the Trp64Arg polymorphism. The frequency of the Trp64Arg variant was significantly higher in hypertensives (13.6%) than normotensives (6.8%; chi 2 5.73, P = 0.017). The 48 subjects with the Trp64Arg variant had significantly higher (P < 0.049) serum triglyceride levels than the 446 with the Trp64Trp variant, while no significant differences were observed, either fasting or during the 75 g oral glucose tolerance test, in glycemia and insulinemia. No differences were found between hypertensive and normotensive subjects for ACE gene insertion/deletion polymorphism nor in the frequency of the Gly40Ser coding change in exon 2 of the glucagon receptor gene.

CONCLUSIONS

Our results are consistent with the thesis that the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene is associated more often with the condition of high blood pressure than with normal blood pressure.

[Hypertrophic cardiomyopathy during adrenocorticotrophic hormone administration in infants: a case report]

We report a 2-month-old child with infantile myoclonic seizures, who developed congestive heart failure secondary to hypertrophic cardiomyopathy while receiving adrenocorticotropic hormone (ACTH) therapy. Treatment with propranolol and withdrawal of ACTH led to the resolution of cardiac hypertrophy as determined by two-dimensional echocardiography. Possible links between ACTH therapy and the development of hypertrophic cardiomyopathy are examined. Our report confirms that a careful monitoring is required to detect cardiac abnormalities during ACTH administration.

Chronic bleeding caused by small bowel angiodysplasia: a problem of recognition and diagnosis

Angiodysplasia of the gastrointestinal tract is a disorder consisting of ectasia of submucosal and mucosal vessels, which causes acute and chronic bleeding. We describe the case of a 58-year-old man with a history of recurrent lower intestinal bleeding and severe anemia. Endoscopy and X-ray examination of the gastrointestinal tract failed to show the source of bleeding. Selective angiography of the superior and inferior mesenteric arteries revealed a vascular ectasia. The patient underwent ileo-cecal resection with remarkable improvement after surgery.

[Discordance between clinical and immunological aspects in a case of chronic B-type lymphoproliferative syndrome]

Chronic lymphoproliferative disorders are extremely heterogeneous from a clinical, morphological and immunological point of view. The paper reports the case of a woman with chronic prolymphocytic leukemia. The neoplastic clone revealed the typical immunological features of pre-B lymphocytes, which are at an earlier stage of differentiation in respect to prolymphocytes. After polychemotherapy (CEOP) the phenotype of the neoplastic cells shifted to an immunological pattern typical of B lymphocytes.

[Ventricular afterload and transmitral Doppler flow profile: effects of the diving test]

The influence of loading conditions on mitral flow velocity profile was studies by pulsed wave Doppler echocardiography in 10 normal subjects during diving test (5 min face exposure to iced water). The cold stimulus increased blood pressure (p less than 0.001), peripheral resistances (p less than 0.001), peak-systolic and end-systolic left ventricular (LV) meridional wall stresses (p less than 0.005). No significant change was found in heart rate. LV end-diastolic volume was unchanged, while LV end-systolic volume increased (p less than 0.005). Consequently, LV fractional shortening decreased (p less than 0.001). Thus, in spite of enhanced LV contractility (assessed by a significant increase in LV end-systolic stress to volume ratio, p less than 0.02) LV pump performance fell, because of prevailing afterload as well as lack of acute recruitment of LV preload reserve (afterload-contractility mismatch). Such an increase in LV afterload was associated with remarkable changes in LV diastolic dynamics: isovolumic relaxation time (IRT) was prolonged (p less than 0.001) and ventricular filling was relatively displaced towards late diastole (peak early to peak atrial velocities ratio, pE/pA: 1.5 +/- 0.3 vs 1.9 +/- 0.3 p less than 0.001; peak atrial filling rate: 326 +/- 47 vs 242 +/- 38 ml/s; p less than 0.001; normalized late diastolic velocity: 0.87 +/- 0.10 vs 0.73 +/- 0.06; p less than 0.01). Also, IRT values significantly correlated with pE/pA values (r = -0.75; p less than 0.001). In conclusion, diving test produced important changes in LV hemodynamics which, in turn, influenced LV relaxation and filling pattern. Our results indicate that operative LV loading conditions should be considered when assessing diastolic function by the analysis of transmitral Doppler flow profile.

Systolic function of the hypertrophied left ventricle

The effects of left ventricular hypertrophy (LVH) on systolic function were studied by echocardiography in 61 hypertensive patients. LV mass index (LVMI) and relative wall thickness (h/r ratio) were used together as LVH indices, and three patterns of LV adaptation to the pressure overload were observed: 13 patients had normal LVMI and h/r ratio (no LVH); 32 patients had increased h/r ratio, with normal or increased LVMI (concentric LVH); 16 patients had increased LVMI and normal h/r ratio (eccentric LVH). Cuff arterial pressure was lower in patients without LVH than in those with LVH, but both LVH indices correlated weakly with systolic, diastolic, and mean blood pressure (r = 0.22 to 0.33). Eccentric LVH showed peculiar hemodynamics, characterized by high cardiac output (CO) and normal total peripheral resistance (TPR), whereas CO was normal and TPR moderately and severely increased in patients without LVH and with concentric LVH, respectively. In the group without LVH, peak systolic stress (PSS) and systolic blood pressure/end-systolic volume index (SBP/Ves) were increased, whereas end-diastolic diameter (EDD), end-systolic stress (ESS), and fractional shortening (FS) were normal; thus, the ejective performance was preserved by increased contractility. The group with concentric LVH had normal PSS, ESS, EDD, and FS and increased SBP/Ves, showing that systolic function was normal or supernormal in the presence of adequate LVH. The group with eccentric LVH had increased PSS, ESS, and EDD, whereas FS and SBP/Ves were both normal; thus, the ejective performance was preserved--in spite of an inadequate LVH and increased afterload--through the action of preload reserve.(ABSTRACT TRUNCATED AT 250 WORDS)

Massive haemorrhagic pericardial effusion in beta-thalassaemia major

The case of a child with beta-thalassaemia major who developed a massive haemorrhagic pericardial effusion is reported and in whom the clinical picture completely resolved after pericardiocentesis. Possible causes are discussed and the role of echocardiography in the follow-up of thalassaemic patients is emphasized.

Genetical and biochemical comparisons of alcohol dehydrogenase isozymes from Anastrepha fraterculus and A. obliqua (Diptera: Tephritidae): evidence for gene duplication

The electrophoretic patterns of the enzyme alcohol dehydrogenase (ADH) from Anastrepha fraterculus and A. obliqua were studied. Two loci were found to code for the enzyme in A. fraterculus, and three in A. obliqua. In both species, all isozymes were active in third-instar larvae. A cationic isozyme (Adh-1) was active mainly in the visceral fat body of both species. In A. fraterculus, the locus had an anionic polymorphic isozyme (Adh-3) that was detected in the parietal fat body. In addition to these two loci, a third locus for an anionic isozyme (Adh-2), which was active in the digestive tube of larvae, was present in A. obliqua and probably resulted from gene duplication. For both species, multiple forms of the isozymes are formed by binding of an NAD-carbonyl compound, as in Drosophila melanogaster. Both larvae and early pupae of A. obliqua had almost twice the specific ADH activity as A. fraterculus. The ethanol content of the host fruit infested with A. obliqua (red "mombim") was also higher than that of the host fruit infested with A. fraterculus (guava).

[Standardized protodiastolic median velocity of the posterior wall (dpwV) used as an index of relaxation in the construction of left ventricular function curves]

The standardized mean protodiastolic speed of the posterior wall (Vpwd), non standardized speed (DEV) and maximum speed (DEVM) obtained with ultrasounds, are capable of distinguishing subjects with hypertrophic subaortic stenosis (IHSS), in whom there is a diminution in compliance, from normal subjects. As this compliance diminution is liable to limit fibrocell lengthening to the extent of its distension speed, the Vpwd has been used in the plotting of ventricular function curves in replacement of telediastolic volume (as an expression of fibre lengthening). An excellent correlation was found between Vpwd and mean speed of circumferential shortening of the fibre (Mvcf) and the ejection fraction (EF) used as indices of cardiac work. The comparison shows that the two groups lie on the same curve of ventricular function and that subjects with IHSS operate low down owing to the brevity of their sarcomeres. The Vpwd can thus be utilized as an indirect index of fibre length and in the plotting of left ventricular function curves.

[Use of normalized velocities in the echocardiographic evaluation of left ventricular performance]

The mean circumferential contraction rate of the myocardial fiber cell (Mvcf) and the ejection fraction (EF) are echocardiographic parameters commonly employed in the assessment of left ventricular performance. In cases where septal asynchonism due to fibrosis or bundle-branch block make their determination impossible, however, one is forced to use parameters obtained from movement of the posterior wall. Investigation of normal subjects and patients with idiopathic hypertrophic subaortic stenosis showed that the "normalized" systolic velocity of the posterior wall (Vpws) and the non-normalized mean velocity (PWV) closely fitted Mvcf and that Vpws offered a good fit with EF. It is suggested that a non-invasive way of obtaining sufficiently reliable data for the evaluation of cardiac performance is offered by these two parameters.

[Study on the medium normalized velocity of circumferential lengthening of the fiber using ultrasound. I. Evaluation of left-ventricular compliance]

The following parameters obtained by echocardiography have been measured in a group of normal subjects and in a group suffering from hypertrophic subaortic stenosis (IHSS): 1) speed of mitral valve protodiastolic closing (MVV); 2) circumferential lengthening speed of the fibre (MVCL) both standardized and otherwise. There is a good correlation between MVCL and MVV (P = 0.01 and 0.05). Since a low mitral valve closing rate is an indirect index for measuring ventricular compliance, the use of the MVCL can be considered valid for the same purposes. Using this it has in fact been possible to distinguish subjects with IHSS in which lower MVV is an index of reduced compliance, from normal subjects.

[Study on the medium normalized velocity of circumferential lengthening of the fiber using ultrasound. II. Use of the construction of left-ventricle performance curves]

Telediastolic pressure and volume can readily be employed as expressions of sarcomere length when constructing ventricular performance curves for the normal heart. In pathological hearts, however, these parameters are rendered inadequate as a result of altered compliance, which means that diastolic lengthening of the muscle fibre cell must be determined from telediastolic stress and linear compliance, corrected for wall thickness (muscle fibre stretch, strain index). Ventricular performance curves were constructed for normal subjects and patients with hypertrophic subaortic stenosis, using the normalised mean rate of circumferential lengthening of the fibre as the expression of fiber strength. Comparison was made with the mean circumferential shortening rate and the ejection fraction as the expression of ventricular effort. It was found that both normal subjects and stenosis patients lay on the same curve, the latter acting low down through having short sarcomeres.

Heart block and hyperthyroidism. Report of two cases

In two patients with hyperthyroidism who had no signs of heart disease, first-degree heart block with tall and large P waves occurred. In one patient, a left bundle-branch block and transient complete heart block with Stokes-Adams episodes also occurred, although there was no verifiable evidence of acute inflammatory disease.