Possible duplication of the hemoglobin alpha chain locus in sheep.

Only one type of alpha chain has been described so far in the hemoglobins of adult domestic sheep. A variant (Hb D) of the alpha chain, characterized by a substitution glycine leads to aspartic acid at position 15, has been described in Yugoslavian sheep. In this paper we report the identification of a second alpha chain (alpha 2), observed in several sheep when the globin was analyzed by CM-cellulose chromatography or the total hemolysate submitted to isoelectric focusing. The ratio of this chain to the usual one (alpha 1) in the globin of different animals is equal to either 1 : 2 or 1 : 4. The structural difference between alpha 1 and alpha 2 chains consists in the replacement of a leucine residue by an histidine in the position 113 or 114 of the polypeptide chain. Preliminary data on the frequency of the alpha 2 chain in eight domestic breeds indicate that this chain is fairly common, being present in 15 out of 40 animals examined. The results of breeding experiments between sheep of an appropriate alpha chain phenotype suggest the possibility of a duplication of the hemoglobin alpha locus in the Ovinae.

[Hemodynamic response to somatostatin at rest and during sympathetic activation in idiopathic orthostatic hypotension]. / Risposta emodinamica alla somatostatina a riposo e durante attivazione simpatica nella ipotensione ortostatica idiopatica.

Idiopathic orthostatic hypotension (IOH) represents a degenerative disorder of the peripheral nervous system characterized by low values of arterial blood pressure during orthostatism, with reduction in serum catecholamines. Since treatment of symptomatic IOH has been unsatisfactory till now, we studied the hemodynamic response to somatostatin (S) (Octreotide, 100 micrograms sc) at rest (R) and during sympathetic activation (tilting, T) by means of 2D and/or color Doppler echocardiography, in 5 ambulatory IOH patients (4M, 1F; aged 65 +/- 5 years), with simultaneous recording of blood pressure and heart rate. Post-S, an increased blood pressure was evident during T without heart rate modifications (pre- vs post-S, SAP: 92 +/- 9 vs 148 +/- 12; DAP: 61 +/- 4 vs 90 +/- 9 mmHg; p less than 0.05), while systolic echo parameters did not change significantly. Doppler aortic velocity curve showed during T a reduction of Vmax (pre- vs post-S: 0.98 +/- 0.09 vs 0.73 +/- 0.03 m/s; p less than 0.05) and of cardiac output, due to unchanged preload. Pre-S, at rest, Doppler mitral velocity curve presented a normal E/A ratio as in normal subjects, with a reduced E peak and an increased A peak post-S, indirect signs of increased afterload. Pre-S, E and A peak velocities underwent progressive decrease during T, markedly more evident post-S. Total peripheral resistance, at rest and during T, increased post-S too (pre- vs post-S, rest: 2406 +/- 267 vs 3162 +/- 599; T: 1634 +/- 201 vs 2784 +/- 425 dyne*s/cm-5; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of cardiac abnormalities and embolic sources in primary antiphospholipid syndrome by transesophageal echocardiography.

OBJECTIVE: Valvular lesions are frequently present in Primary Antiphospholipid Syndrome (PAPS) patients using transthoracic and/or transesophageal echocardiography. The aim of this study was to describe the prevalence of cardiac abnormalities (valvular thickening and/or regurgitation) or potential embolic sources (spontaneous echocontrast and/or vegetations) in PAPS patients. METHODS: Multiplane transesophageal echocardiography was performed consecutively on 40 PAPS PATIENTS: 17 of them with thrombocytopenia, 27 with at least one thromboembolic event (stroke, transient ischaemic attack, arterial and/or venous thrombosis, pulmonary embolism) and 14 with recurrent fetal loss. DESIGN: Cardiac involvement (cardiac abnormalities and/or embolic sources) was present in 33/40 (82%) of PAPS patients. According to aCL titer these lesions were revealed in 17/24 (71%) of patients with aCL < or = 40 GPL-U, while these lesions were present in 100% of patients with aCL > 40 GPL-U. Three patients presented mitral stenosis and 3 non-infective valve masses or vegetations. Embolic sources were found in 4/24 (17%) patients with aCL < or = 40 GPL-U, while they were observed in 6/16 (37%) of patients with titer of aCL > 40 GPL-U (chi2 = 10.03, P < 0.01). Regression analysis showed a positive correlation between mitral valve thickening and aCL antibodies titer (r = 0.5; P < 0.001). CONCLUSIONS: Valvular lesions are commonly found in PAPS patients. Our data showed a significant correlation among aCL titer, mitral leaflets thickening and thromboembolic events.

Sympathetic predominance followed by functional denervation in the progression of chronic heart failure.

Using spectral analysis of heart rate and systolic arterial pressure variabilities, the study was set up to evaluate cardiovascular efferent autonomic modulation in patients with different degrees of chronic heart failure. We studied 30 patients with stable chronic heart failure and 15 controls of similar age. ECG, arterial blood pressure and respiratory signal were recorded at rest, during controlled respiration and during passive head-up tilting. R-R interval periods of 256-512 were analysed. Routine 2D echocardiogram and Doppler studies were also carried out. As expected, we found a decrease in the mean and variance of R-R intervals in patients with sever heart failure. In New York Heart Association (NYHA) class II patients, the power spectral pattern of R-R variability was characterized by the predominance of the low frequency component (72 +/- 3 nu), considered a marker of sympathetic activity, and by its unresponsiveness to tilting. Patients in NYHA class III also presented blunted changes in spectral components during tilting. A drastic decrease in the variance of R-R intervals (191 +/- 58 vs 1056 +/- 149 ms2 in controls) and an almost complete absence of the low frequency spectral component (8 +/- 3 nu) were present in patients in NYHA class IV. Controlled respiration, which in normal subjects decreased the low frequency component, induced changes that blunted progressively as heart failure increased. These data suggest that autonomic neural modulation and cardiovascular response to neural activity differ at different stages of the disease.

[The role of mitral regurgitation in the neurovegetative regulation of mitral valve prolapse]. / Ruolo del rigurgito mitralico nella regolazione neurovegetativa del prolasso della mitrale.

To define the role of mitral regurgitation (MR) on sympatho-vagal balance in mitral valve prolapse (MVP) patients, we analyzed 41 ambulatory MVP symptomatic patients. Twenty-seven patients (4 males, 23 females, aged 34 +/- 3 years) had significative MR assessed color Doppler, while 14 patients (5 males, 9 females, aged 29 +/- 3 years) had no MR; 36 age- and sex-matched subjects were studied as controls (C). Spectral analysis of heart rate variability (HRV) was performed at rest and during sympathetic activation (tilt). In the whole group of MVP patients spectral components did not differ significantly from C at rest and during tilt. When patients were subdivided in relation to the presence (+) or absence (-) of MR, HRV revealed in MR+ patients at rest an increased high frequency (HF) and a diminished low frequency (LF) component (47 +/- 5 and 41 +/- 5 normalized units, nu) with respect to C (34 +/- 3 and 54 +/- 3 nu, p < 0.05, respectively). Viceversa during tilt, in MR+ patients it was possible to observe a LF increase greater than in C (delta LF: 36 +/- 4 versus 25 +/- 3 nu, p < 0.05). As HF component is currently interpreted as a marker of vagal modulation of HRV, our results suggest an increased vagal tone associated with MR possibly due to stimulation of atrial vagal receptors; moreover, an increased sympathetic responsiveness to tilt seems to characterize MR+ patients.

[Multiplanar transesophageal echocardiography in a case of hypernephroma]. / Ecocardiografia transesofagea multiplanare in un caso di ipernefroma.

A 78-year-old man admitted to our hospital with signs and symptoms of right ventricular failure, consisting of severe edema of the scrotum and the penis, ankle edema, hepatomegaly, and a history of asthenia associated with a recent weight loss. Two-dimensional echocardiography showed an intracavitary mass in the right atrium and a moderate pericardial effusion; the remaining structures were normal. To better define the origin of this mass, transesophageal echocardiography was performed. The mass extended from the inferior vena cava with no sites of attachment to the atrial wall. The mass was elongated, mobile, with a triangular termination near the tricuspid valve, without signs of right ventricular obstruction. An abdominal-pelvic CT scan demonstrated the origin of the mass at the superior pole of the left kidney extending through the renal vein and the inferior vena cava into the right atrium. The mass was surgically removed and the pathological examination revealed a renal cell carcinoma (hypernephroma) of the clear cells subtype. After surgery, the patient did well with the resolution of the picture of right ventricular failure.