[Arrhythmogenic cardiomyopathies of the right ventricle]

Arrhythmogenic cardiomyopathies of the right ventricle (ACRV) are defined by an association of left delayed type ventricular arrhythmias, ranging from apparently uncomplicated extrasystoles to more severe or even potentially lethal arrhythmias such as polymorphous VT and ventricular fibrillation, with an anatomical substrate consisting of adipose or fibro-adipose degeneration of the myocytes of the free wall of the ventricle, which may be either focal (in particular: apex, anterior surface of the infundibulum and the sub-tricuspid region), or more diffuse. It is then accompanied by RV systolic dysfunction with dilatation of the cavity. This apparently well defined clinico-pathological entity is in fact more complex, if only because of the existence of associated lesions of the left ventricle in 1/3 of cases. The distinction from Uhl disease remains blurred, in particular in diffuse forms. It is most probable that more than one etiology is involved. A dysgenetic mechanism with probable autosomal dominant transmission has apparently been shown in familiar forms which are associated with a particularly severe risk of progression. The hypothesis of sequelae of multifocal myocarditis appears to be the most probable in sporadic forms. In the absence of histological criteria, which it is difficult to demand in view of the variability of results and potential dangers of endomyocardial biopsy involving such thin and fragile ventricular walls, the diagnosis of ACRV is based upon the concomitant existence of: (1) electrophysiological criteria: ventricular arrhythmias, in particular sustained monomorphous VT, with the particular feature of a very high degree of sensitivity to adrenergic stimulation (exercise), the existence of late potentials on the high amplification ECG, a highly specific sign, though unfortunately of poor sensitivity in localized froms, those which are most difficult to identify (2); segmentary morphological and kinetic RV abnormalities, most often resulting in localized akinetic or dyskinetic parietal vaulting, with stasis "in situ". Modern imaging methods (echocardiography, angioscintigraphy with phase analysis, nuclear magnetic resonance imaging, etc.) unfortunately do not yet offer an alternative to selective cineangiography of the RV which is the reference investigation when it is performed and interpreted under strict conditions. Several reports of sudden death or of ventricular fibrillation seen in confirmed cases of ACRV, as well as the publication of a number of autopsy registers indicating that this condition is one of the primary causes of sudden death in young individuals and in athletes, have cast doubt on the benign prognosis initially attributed to this condition.(ABSTRACT TRUNCATED AT 400 WORDS)

[Influence of exercise on the permeability of accessory pathways and supraventricular arrhythmia in Wolff-Parkinson-White syndrome]

The influence of adrenergic stimulation on the effective anterograde refractory period of the accessory pathways and on supraventricular arrhythmias, was studied in 20 patients (average age 38 +/- 16 years) with an untreated permanent Wolff-Parkinson-White syndrome and a resting anterograde refractory period < or = 400ms. Repeated electrophysiological studies with a single endocavity catheter positioned near the atrial pole of the accessory pathway were performed under basal conditions and during a standardised exercise test on a bicycle ergometer. The effective anterograde refractory period of the accessory pathway, the length of the tachycardia cycle during reciprocating orthodromic tachycardia, the average heart rate, the percentage of preexcited QRS complexes during induced atrial fibrillation, were measured in all patients under basal conditions and at the peak of exercise. Exercise significantly reduced the anterograde refractory period of the accessory pathway (287 +/- 49 ms at rest versus 238 +/- 24 ms on exercise: p < 0.001), the cycle of orthodromic tachycardia (302 +/- 32 vs 260 +/- 22 ms p < 0.001), the minimal R-R interval (270 +/- 65 vs 227 +/- 46 ms: p < 0.05) and % of preexcited QRS complexes (75 +/- 33 vs 51 +/- 39: p < 0.05) in atrial fibrillation whilst increasing the average heart rate (165 +/- 42 vs 202 +/- 39 bpm: p < 0.02). Adrenergic stimulation significantly improves anterograde conduction in the accessory pathway. The reduction in the % of preexcited QRS complexes in atrial fibrillation could indicate a preferential action of catecholamines on the nodo-hisian pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

[Results of coronary-angiographic evaluation after endocavitary fulguration of the accessory pathways]

Left ventricular aid coronary angiography was performed systematically in 32 consecutive patients (average age 34 +/- 16 years) to assess the potential risk of coronary and myocardial lesions after high energy catheter ablation of an accessory pathway. The control was performed 2 to 6 months after the procedure in 30 patients and as an emergency immediately after the procedure in 2 patients because of prolonged ST segment elevation in 1 and an echocardiographic abnormality in the other. The catheter ablation was performed by a right heart approach in 19 patients and by retrograde catheterisation of the left heart in the other 13. The average number of shocks delivered was 3.6 +/- 2.4 in 1.8 +/- 1.2 session with an average energy of 632 +/- 220 joules. The global success rate was 88%, 70% complete successes and 18% clinical successes. The left ventricular and coronary angiographies were normal in 31 patients, including the 2 patients investigated as an emergency. On the other hand, one totally asymptomatic patient in whom a left lateral bundle of Kent had been ablated 2 months previously by a retrograde transaortic approach, had a large pseudo-aneurysm of the left ventricular posterior wall and coronary angiography showed a fistula between the first lateral branch of the circumflex artery and the left ventricle. At surgery, a localised rupture of the mitral annulus was confirmed. Two factors may at least partially explain this complication: the quantity of energy delivered (1,000 joules) in a single session to a limited area, and the site of ablation on the ventricular side of the mitral annulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between up-regulation of lymphokine mRNA and down-regulation of TcR, CD4, CD8 and lck mRNA as shown by the effect of CsA on activated T lymphocytes

Full activation of different T cell populations via the TcR/CD3 complex leads to transient expression of lymphokine mRNA and to transient and specific down-modulation of TcR, CD4, CD8 and p56lck mRNA (Multi-Receptor Complex or MRC mRNA). This transient down-modulation is due to both a decrease in transcription and stability of these mRNA and is temporally and quantitatively related to lymphokine mRNA induction. We showed that cyclosporin A (CsA), which blocks lymphokine expression also inhibits MRC mRNA down-modulation at the transcriptional level, and does not affect mRNA stability. The fact that CsA inhibits both lymphokine expression and MRC mRNA down-modulation at transcriptional level supports a model in which similar signals trigger the inverse regulation of these two sets of genes via identical transcriptional factors.

Down-regulation of lck mRNA by T cell activation involves transcriptional and post-transcriptional mechanisms

The p56lck tyrosine kinase is most likely to be involved in signal transduction of T lymphocyte activation. After full activation through the TcR/CD3 complex lck mRNA is transiently down-modulated. This down-modulation was due to an early decrease of both transcription and stability of the lck mRNA. To study the involvement of transcriptional and post-transcriptional factors in this regulations, we have analysed the effect of cycloheximide, a protein synthesis inhibitor, on the steady-state of the lck mRNA. Cycloheximide superinduced lck mRNA by increasing its stability, although cycloheximide concomitantly decreased lck transcription. This suggests that the constitutive level of lck mRNA observed prior to activation is controlled by transcriptional activator(s) and post-transcriptional destabilizing factor(s). Second, lck mRNA down-modulation observed after full activation was inhibited by cycloheximide. It increased lck mRNA stability whereas lck transcription remained low. Therefore, full activation might increase the synthesis and/or activity of destabilizing factor(s). Cyclosporin A also inhibited the down-modulation of lck mRNA by increasing its transcription with no effect on its stability. Since, lck mRNA down-modulation was always associated with lymphokine mRNA induction, and since CsA blocks both lymphokine transcription and lck decrease of transcription, this indicates that these genes might share common regulatory pathways leading to their inverse transcriptional regulation.

Chronic effects of tertatolol on renal function in hypertensive patients with mild chronic renal failure

To assess the potential benefit of drug-induced renal haemodynamic changes in patients with chronic renal failure, we have evaluated the effects of the beta-blocking agent tertatolol on blood pressure, glomerular filtration rate, and renal plasma flow. Inulin and PAH clearances were performed before and after 3 months treatment and oral tertatolol, 5 mg daily in eight hypertensive patients with moderate chronic renal failure. After 3 months of treatment, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) increased significantly by 10% and 13% respectively, whereas renal vascular resistance decreased by 16% and the filtration fraction was unchanged. These results indicate that tertatolol possesses novel renal haemodynamic properties in hypertensive patients with chronic renal failure. However, the long-term benefit of such a therapy is yet to be confirmed.

Dynamic electrophysiology of ventriculoatrial conduction: implications for DDD and DDDR pacing

The behavior of ventriculoatrial conduction (VAC) during exercise remains unknown. In order to determine its characteristics and the consequences it might have on dual chamber pacemaker technology and programming, 17 patients underwent an electrophysiological study (EPS) of atrioventricular conduction (AVC) and of VAC during a protocol including three steps: supine rest, upright position, and finally during cycloergometric exercise; the measurements were done at progressively increasing pacing rates. During a preimplantation EPS, Wenckebach points AVC-W and VAC-W and conduction times, AVCT and VACT (as a function of pacing rate), were measured in ten consecutive patients using temporary leads and an external device. In another study, AVCT, VACT, AVC-W, and VAC-W were measured by telemetric recordings under identical conditions in seven patients implanted earlier with a DDD pacemaker. A 1/1 VAC was observed in 7/17 patients (41%) at rest, and in 13/17 patients (76%) at the end of the protocol; VAC was never observed in 4/17 patients (23%), but occurred in six of the ten patients initially free, three standing at rest and three on exercise. For all patients, the VAC behavior remained of "nodal" type, indicated by a progressive increase in VACT as pacing rate rose up to the VAC-W point. Neither the existence of exercise-induced VAC nor the maximal VACT-W could be predicted from AVC or VAC data obtained at rest. However, at the same pacing rates, standing up and exercise induced a shortening effect on VACT, and improved the VAC-W by an average of 33%. These results suggest that the electrophysiological behavior of VAC does not obey any general rule and cannot be predicted individually. It would thus appear unwise to base pacemaker mediated tachycardia (PMT) protection solely on long postventricular atrial refractory period (PVARP) programming in DDD patients. This work also revealed the potential risks of a rate responsive auto-adaptive PVARP algorithm as proposed in certain new devices.

[Benefits and limits of single chamber atrial pacing with adaptive rate]

Twelve patients with isolated symptomatic sinus node dysfunction or bradycardia-tachycardia syndrome with atrial chronotropic incompetence during exercise testing were managed by single chamber rate responsive atrial pacing (AAIR) when AV conduction was normal, or by a dual chamber DDDR pacemaker programmed in the AAIR mode when AV conduction was abnormal, and followed up for 12.5 +/- 9.8 months. The patients were assessed clinically, by 3 monthly ECG and Holter recordings and comparative exercise tests in AAI and AAIR modes at the 6th month. One patient with an AAIR system was excluded at M21 because of symptomatic AV block requiring reimplantation of a DDD pacemaker. Ten of the 11 remaining patients are asymptomatic and have an excellent quality of life; one patient had invalidating symptoms on exercise attributed to the "AAIR pacemaker syndrome" which were corrected by reprogramming the pacemaker and modifying the medical therapy. The comparative exercise stress tests showed a significantly higher heart rate in the AAIR mode compared to AAI pacing at the initial and intermediate exercise levels (30 to 70 W); on the other hand, the heart rates were not significantly different at the highest exercise levels although in the AAI mode, the terminal acceleration sometimes occurred in junctional rhythm whereas it was usually an atrial paced rhythm in the AAIR mode. The total duration of exercise was longer in the AAIR mode (+22%; p less than 0.01) when the 8/11 patients with chronotropic incompetence during the baseline study were considered. The spike-R interval adapted normally to exercise in only one case: in the other patients, the interval remained constant or, in the worst of cases (N = 4), it increased paradoxically, to result in the "AAIR pacemaker syndrome": this phenomenon is observed mainly in patients treated by antiarrhythmics and/or betablockers. The AAIR mode would therefore seem to be a simple, effective and reliable method of treating patients with sinus node dysfunction and chronotropic incompetence; however, the failure of adaptation of the PR interval is a real limitation to its use and may constitute an argument in favour of the choice of a DDR pacemaker in these patients.

Transcriptional and post-transcriptional regulation of TcR, CD4 and CD8 gene expression during activation of normal human T lymphocytes

We previously showed that the turnover rates of the messengers coding for the T cell receptor (TcR) alpha, beta and gamma, CD4 and CD8 molecules composing the multireceptor complex vary in normal human mature T lymphocytes according to their state of activation. Activation by soluble anti-CD3 which does not induce proliferation, promotes a weak up-modulation of the corresponding five mRNAs. In contrast, activation signals such as anti-CD3 + PMA, which lead to lymphokine mRNA expression and T cell proliferation, promote a decrease of the TcR, CD4 and CD8 mRNA levels within 4 h post-activation, followed by their gradual re-expression. Here we show that the down-modulation of these mRNAs results from early regulation controls at transcriptional and post-transcriptional levels, i.e. through a concomitant inhibition of transcription and destabilization of the mRNA. Moreover, later re-expression of the mRNA results from recovery of transcription and marked increase of the mRNA stability. Finally, down-modulation is specific for TcR, CD4 and CD8 mRNAs, all submitted to similar regulation processes. These results strongly suggest a direct correlation between down-modulation of the multireceptor complex mRNAs, and lymphokine mRNA expression, and cellular proliferation.

[Myocardial infarction and massive biventricular thrombosis during thrombocytopenia induced by pentosan polysulfate and heparin]

Many cases of immuno-allergic thrombocytopenia complicated by serious thromboembolism induced by heparin or other heparinoids such as pentosan polysulphate have been reported. This case is of interest for two reasons: first of all, it was induced by pentosan polysulphate and then reactivated by secondary administration of heparin; secondly, it was complicated successively by an infero-apical myocardial infarction with probable spontaneous lysis of a coronary thrombosis because coronary arteriography performed one month later was normal, and then by massive biventricular thrombosis requiring surgical thrombectomy under cardiopulmonary bypass. Tests of platelet aggregation were positive to standard heparin and to several low molecular weight fractions. The outcome was favorable when the responsible substances were withdrawn.

[Auriculoventricular block disclosed in the exercise test]

Sixteen patients, 14 of whom described stress related symptoms, present a severe atrio-ventricular block (A-V B), identified during a stress test while the ECG at rest showed a 1/1 atrioventricular conduction (AV). The electrophysiological study (EPS) creates the A-B Block through atrial stimulation and specifies the location of the A-V B: intra-hissian in 8 patients (7 with small QRS an 1 with widened QRS) and infra-hissian in 8 patients (all with widened QRS). Non-invasive methods constitute the prime approach in the diagnostic work-up of stress symptoms. The ideal treatment consists of a dual-chamber cardiac stimulation.

Short tertatolol treatment does not impair the hormone and metabolic responses to exercise and hypoglycemia in diabetics

Beta-blockers can precipitate hypoglycemia and mask its warning signs. Ten male insulin-dependent, otherwise healthy diabetic patients underwent two submaximal exercise tests and two insulin-induced hypoglycemic events (0.2 u/Kg short-acting insulin IV) after six days administration of placebo followed by tertatolol, a non selective beta-blocker (5 mg once daily). Tertatolol modified neither the exercise-induced changes in blood glucose, lactate and plasma unesterified fatty acid levels, nor those of counter regulatory hormones (glucagon, growth hormone, cortisol), while blood pressure, heart rate and plasma renin activity were significantly reduced, proving that tertatolol had actually been ingested, and was active. During the insulin-induced hypoglycemia, similarly tertatolol did not modify the course of the plasma fuels and hormones. Particularly, hypoglycemia was neither deeper nor more prolonged in the presence than in the absence of tertatolol. Warning symptoms were not affected except for palpitations which were not perceived. These results suggest that tertatolol did not precipitate hypoglycemia following exercise, and did not aggravate insulin-induced hypoglycemia in short term administration, and in otherwise healthy diabetic patients.

Benefits and limits of selective right ventricular cineangiography in arrhythmogenic right ventricular dysplasia

Cineangiographic data from patients with probable arrhythmogenic right ventricular dysplasia (ARVD) were compared with those from matched controls. Some changes previously thought to indicate ARVD did not do so in this study. The abnormalities specific for ARVD were free wall morphological and wall motion abnormalities, particularly bulges and mamillated akinetic areas.

Lymphokine mRNA and T cell multireceptor mRNA of the Ig super gene family are reciprocally modulated during human T cell activation

The expression of genes, implicated in T cell proliferation as well as those coding for the three chains of the T cell receptor (TcR) and for the CD4 and CD8 molecules, has been investigated during activation of various T cell populations maintained in long-term culture. We show that a minimal activation signal, capable of inducing interleukin 2 (IL 2) receptor expression without the expression of IL2 and interferon-gamma, was not associated with a down-regulation of the messengers coding for the T cell multireceptor molecules. In contrast, a strong activation signal via the TcR/CD3 complex or via the CD2 molecule resulted in a reciprocal transient up-regulation of the messengers implicated in T cell proliferation and a down-regulation of the messengers encoding the molecules of the TcR complex of the immunoglobulin super gene family.

Vitamin D metabolism in tuberculosis. Production of 1,25(OH)2D3 by cells recovered by bronchoalveolar lavage and the role of this metabolite in calcium homeostasis

To investigate the extrarenal production of 1,25(OH)2D3 in tuberculosis, we extensively evaluated a patient with tuberculosis, hypercalcemia, and an elevated plasma concentration of 1,25(OH)2D3. Fresh total cells and cultured alveolar macrophages obtained by bronchoalveolar lavage were demonstrated to synthesize 1,25(OH)2D3 prior to and after nine months of successful antituberculous therapy. The continued capacity to produce 1,25(OH)2D3 was associated with a persistent lymphocytic alveolitis in this patient. This extrarenal production of 1,25(OH)2D3 probably contributed to the increased levels of plasma 1,25(OH)2D observed in our patient. Nevertheless, a close correlation between plasma 1,25(OH)2D and serum calcium was not observed. These findings suggest that although extrarenal production of 1,25(OH)2D3 occurs in tuberculosis, it need not be a predominant factor producing the abnormalities in calcium homeostasis observed in such patients.

[Proximal migration of a caval filter. Apropos of a case]

We are reporting of proximal migration, intracardiac, of a percutaneous caval filter (LEM type), resulting in the death of the patient. It is a true, early (1st week) migration after accurate positioning, opposite L4, and not an incident of insertion.

Atrial natriuretic factor during atrial fibrillation and supraventricular tachycardia

Plasma immunoreactive atrial natriuretic factor was measured in 10 patients with chronic atrial fibrillation before and after cardioversion to sinus rhythm, and in 14 patients during electrophysiologic evaluation of paroxysmal supraventricular tachycardia. The mean plasma concentration of atrial natriuretic factor in atrial fibrillation was 138 +/- 48 pg/ml and decreased to 116 +/- 45 pg/ml 1 hour after cardioversion to sinus rhythm (p less than 0.005). The mean plasma concentration of atrial natriuretic factor increased from 117 +/- 53 pg/ml in sinus rhythm to 251 +/- 137 pg/ml during laboratory-induced supraventricular tachycardia (p less than 0.005). Right atrial pressures were recorded in 12 patients; the baseline atrial pressure was 4.3 +/- 1.9 mm Hg and increased to 7.4 +/- 3.6 mm Hg during supraventricular tachycardia (p less than 0.005). A modest but significant linear relation was noted between the changes in plasma atrial natriuretic factor and right atrial pressure measurements during induced supraventricular tachycardia (r = 0.60, p less than 0.05). In conclusion, changes in atrial rhythm and pressure may be an important factor modulating the release of atrial natriuretic factor in the circulation and raised levels of this hormone may be a contributing factor for the polyuria and the hypotension associated with paroxysmal supraventricular tachyarrhythmias.

Effects of tertatolol in hypertensive patients with chronic renal failure

Chronic renal failure (CRF) is often associated with hypertension, as a cause or a consequence. We studied the changes in blood pressure (BP), heart rate (HR), renal function (as measured by creatinine clearance), and plasma renin activity (PRA) in 19 hypertensive patients with CRF before, during and after oral administration once a day for at least 30 days of 5 mg tertatolol, a new beta-blocker. All patients were free of any antihypertensive medication for at least 1 month before administration of tertatolol. The dose of tertatolol given in this study was the same as that commonly used in patients with normal renal function. From day 0 to day 30 of tertatolol, measurements in the supine position were as follows: systolic BP (SBP) decreased from 168.4 +/- 4.6 to 145.3 +/- 4.3 mm Hg (p less than 0.01); diastolic BP (DBP) decreased from 106.1 +/- 2.4 to 87.1 +/- 2.0 mm Hg (p less than 0.01); HR decreased from 77.9 +/- 1.6 to 63.2 +/- 1.7 b.p.m. (p less than 0.01); PRA decreased from 1.816 +/- 0.521 to 1.052 +/- 0.323 ng/ml/h (p less than 0.01). Creatinine clearance remained stable: 37.1 +/- 4.1 versus 37.1 +/- 4.7 ml/min/1.73 m2 (not significant). Similar results (for SBP, DBP, HR and PRA) were obtained in the erect position. It is concluded that tertatolol in hypertensive patients with CRF: significantly lowers BP and HR without excessive bradycardia, significantly lowers PRA, the most important decrease being observed for the highest initial PRA, does not alter renal function, and has a good clinical acceptability.

Renal hemodynamic effects of tertatolol in essential hypertension

Tertatolol, a new beta-blocker, and propranolol, considered a reference beta-blocker, were given orally (5 and 160 mg slow release, respectively) for 15 days to two groups of patients with essential hypertension in order to compare their effects on renal hemodynamics. Systolic and diastolic blood pressure, heart rate, and erect plasma renin activity fell significantly in both groups while prostaglandin E2 urinary excretion was unchanged. Tertatolol administration produced increases in glomerular filtration rate, as shown by inulin clearance (+8.9%; p = 0.038) and renal plasma flow, as shown by paraaminohippurate clearance (+13.0%; p = 0.007). In contrast, propranolol administration resulted in a slight decrease in glomerular filtration rate (-2.8%; not significant) and a fall in renal plasma flow (-13.4%; p less than 0.001). Comparison between both treatments showed that glomerular filtration rate and renal plasma flow were higher in the patients treated with tertatolol than in those treated with propranolol whereas filtration fraction was lower, which suggests that tertatolol causes a vasodilation of the glomerular afferent arteriole. These results demonstrate that in contrast to propranolol (160 mg), and despite both drugs exhibiting a comparable antihypertensive activity, tertatolol (5 mg) does not alter but even improves renal perfusion in hypertensive patients.

Hypertension induced by repeated exposure to high sustained +Gz (HS + Gz) stress

The purpose of this study was to determine whether repeated exposure to high sustained +Gz (HS + Gz) stress induced persistent changes in the functional state of the cardiovascular system. Three groups of rabbits--centrifuged, restrained, and control--were studied. After being placed in the restraining system of the centrifuge, the animals were submitted three times in a row to 8-9 +Gz sustained for 40 s. This exposure was repeated three times a week for 3-6 weeks. Restrained animals were not exposed to HS + Gz. Control animals were not restrained. The two types of stress (centrifuge + restraint; restraint alone) determined the appearance of two types of arterial hypertension. Systolic arterial pressure (AP) and left ventricular pressure (LVP) significantly increased in restrained animals. The function of the cardiovascular system was more perturbed in centrifuged rabbits since the significant changes affected not only systolic AP and LVP but alos systemic diastolic AP and the maximum rate of rise of LVP. The myocardium of rabbits repeatedly subjected to HS + Gz exposures, except for those that suffered a fracture of the lumbar spine, was significantly glycogen-depleted.

Resorptive versus absorptive hypercalciuria in sarcoidosis: correlations with 25-hydroxy vitamin D3 and 1,25-dihydroxy vitamin D3 and parameters of disease activity

Sarcoidosis is frequently attended by hypercalciuria and sometimes by hypercalcaemia. The type of hypercalciuria and its relationships with disease extension and activity have rarely been investigated. In order to clarify these issues we undertook an investigation by a calcium absorption test in 39 patients with untreated thoracic sarcoidosis, and tried to establish correlations with vitamin D3 metabolism and some features of the disease. We found three types of responses. Group I (n = 12) with a normal test had normal 1,25-(OH)2D3 and rare extrathoracic localisations. Group II (n = 14) with absorptive hypercalciuria had higher serum calcium; 1,25-(OH)2D3 (p less than 0.001) and the free 1,25-(OH)2D3 index (p less than 0.05) were raised. Sarcoidosis was more often inflammatory, developing and disseminated. Group III (n = 13) had resorptive hypercalciuria, and hypercalcaemia was frequent. 1,25-(OH)2D3 (p less than 0.01) and the free 1,25-(OH)2D3 index (p less than 0.05) were raised but to the same degree as in Group II. Sarcoidosis was more disseminated and developing than in Groups I and II. In the 39 patients, iPTH and nephrogenous cAMP were low. Post-calcium load urinary calcium/creatinine (Ca/Cr) and 1,25-(OH)2D3 were correlated (p less than 0.05). Extrathoracic extension was associated with higher fasting urinary Ca/Cr (p less than 0.001), and development with higher post-load urinary Ca/Cr (p less than 0.001). Thus, absorptive hypercalciuria is related to the development of sarcoidosis and can be explained by high free 1,25-(OH)2D3, while resorptive hypercalciuria seems to be linked with disease extension. In such a case, the mechanism of osteolysis is not solely accounted for by high 1,25(OH)2 vitamin D3 serum levels, and we postulate that some other factor is at work, related to the extent of the granulomatous process.

Paraneoplastic hypercalcemia associated with bladder carcinoma: report of 2 cases

Hypercalcemia associated with bladder carcinoma is rare. We report on 2 patients with hypercalcemia and bladder tumor without bone metastases. In both patients serum calcium returned to normal after removal of the tumor. Serum immunoreactive parathyroid hormone levels were normal in both patients. In 1 case a high gradient of immunoreactive parathyroid hormone across the tumor was demonstrated but the secretion of nephrogenous cyclic adenosine monophosphate was normal. Urinary excretion of prostaglandins also was normal in this case. These data show that hypercalcemia was caused by the tumoral production of some humoral factor different from parathyroid hormone.

Metabolic clearance rate of immunoreactive vasopressin in man

Metabolic clearance of synthetic arginine vasopressin (AVP) has been measured in sixteen healthy subjects and ten uraemic patients on maintenance haemodialysis. Plasma AVP was measured using a specific radioimmunoassay at different intervals after a single injection of 2 micrograms AVP. The theoretical curve which fitted best with the disappearance curve was the sum of two exponentials in twenty-two subjects and of three exponentials in the other four. Metabolic clearance rate and the volume of fast initial distribution were 287.1 ml min-1 (m2)-1 and 219.3 ml/kg b.w., respectively, in normal subjects. Metabolic clearance rate was considerably lower in the uraemic group. This emphasizes the role of kidneys in the degradation of AVP and may account, at least in part, for the higher basal plasma value of this hormone observed in uraemic patients.

[Contribution of radioimmunologic determination of parathyroid hormone (PTH) to the diagnosis of hyperparathyroidism (HPT) (38 cases]

The P.T.H. radioimmunoassay was done in 38 cases of suspected H.P.T. In confirmed primary H.P.T., the dosage was in positive correlation in 75% of cases; the classic metabolic exploration was in good correlation in 81% of cases. The specificity of the dosage is good but the defect of correlation comes from the antiserum utilised which recognizes the NH2-terminal region of human P.T.H.

Influence of salmon calcitonin on radiophosphorus distribution in polycythaemic patients

1. Salmon calcitonin injected 5 min after a therapeutic dose of 32P in polycythaemic patients produced a significant increase in rate of disappearance of 32P from plasma when compared with a control group.

2. Salmon calcitonin injected 120 min after 32P injection did not modify the curve of 32P disappearance from plasma.

3. Salmon calcitonin injected 10 days after 32P injection did not produce any change in 32P plasma radioactivity or specific radioactivity.

RÉSUMÉ

1. La calcitonine de saumon (sCT) injectée 5 min après une dose thérapeutique de 32P chez des malades polyglobuliques produit une disparition du 32P du plasma plus rapide que dans un groupe témoin.

2. La sCT injectée 120 min après le 32P ne modifie pas la courbe de disparition du 32P du plasma.

3. La sCT injectée 10 jours après le 32P ne produit aucun changement dans la radioactivité (RA) ou l'activité spécifique (SA) du 32P du plasma.

Effect of bovine parathyroid hormone 1-34 fragment on renal production and excretion of adenosine 3', 5' monophosphate in man

Biologically active bovine parathyroid hormone (b PTH) 1-34 fragment infused over one hour in normal subjects produced an immediate and sharp increase in the excreted fractions of filtered bicarbonate, sodium and potassium, followed by the return to pre-infusion levels as soon as the administration of b PTH was stopped. There was a gradual but steady increase in the excreted fraction of filtered phosphate but a decrease in the excreted fraction of filtered calcium and magnesium. The excreted fractions of these ions were still abnormal 150 minutes after the completion of PTH infusion. The urinary excretion of 3'5'-cyclic AMP increased immediately about one hundred-fold but returned rapidly to pre-infusion levels. Urinary clearance of cyclic AMP approximated glomerular filtration rate in control periods and was twenty to thirty times greater during b PTH infusion. In subjects overloaded with bicarbonate, b PTH brought about a decrease in bicarbonate T(m) and the same effects on the urinary excretion of other electrolytes. 3'5'-cyclic AMP excretion was clearly higher in control periods and reached higher levels during b PTH infusion when compared to subjects without an alkaline load. 3'5'-cyclic AMP excretion and fractional clearance were also clearly higher in subjects not given b PTH when control periods were compared to periods with bicarbonate infusion or after acetazolamide administration. During distal blockade obtained by simultaneous administration of chlorothiazide and ethacrynic acid, there was a delay in the rise of 3'5'-cyclic AMP excretion after b PTH administration. It can be concluded from these studies that the pattern of excretion of 3'5'-cyclic AMP is similar to that of bicarbonate, sodium and potassium. The increase of 3'5'-cyclic AMP excretion when urinary pH is above 7 suggests a diffusion trapping mechanism for the secretion into the lumen of this nucleotide. Distal diuretics used in distal blockade did not inhibit 3'5'-cyclic AMP production but delayed its secretion into urine.