Primary Aldosteronism

ABSTRACT A follow-up examination was performed one month to 20 years after adrenalectomy in 28 cases with surgically treated primary aldosteronism due to adrenal adenoma. The mean age at diagnosis was 45, and the mean duration of hypertension seven years. Severe hypertension with a diastolic blood pressure of 130 mmHg or more was observed in 35%. Postoperatively cerebrovascular catastrophe developed in two cases, both of which belonged to the group of patients with severe hypertension. Normalization of blood pressure was observed in 70% and in the remaining subjects the blood pressure was lower than at diagnosis. The blood pressure response to adrenalectomy appeared unpredictable in view of such parameters as the initial blood pressure, age at diagnosis, and duration of the hypertensive state. Toxicosis during pregnancy and metrorrhagia was observed with unexpectedly high frequency in this study population. Low ambulatory plasma renin activity was recorded at the follow-up in 15 out of 18 subjects studied in the absence of evidence of hyperaldosteronism.     

Proximal tubular function in adult rats treated neonatally with enalapril

Neonatal treatment with angiotensin-converting enzyme (ACE) inhibitors or the angiotensin II type-1 receptor antagonist losartan in rats induces irreversible renal histological abnormalities, mainly papillary atrophy, in association with an impairment in urinary concentrating ability. The aim of the present study was to assess proximal tubular function in adult rats treated neonatally with enalapril. Male Wistar rats received daily, intraperitoneal injections of either enalapril (10 mg kg^?1) or isotonic saline vehicle from 3 to 24 days of age. In 15-week-old, hydropenic rats we analysed: (i) proximal tubular iso-osmotic fluid reabsorption using the method of lithium clearance; and (ii) maximal tubular D -glucose reabsorption (Tm_G), under pentobarbital anaesthesia. The main findings were that neonatally enalapril-treated rats showed: (i) reductions in absolute (APRH₂O) and fractional (FPRH₂O) iso-osmotic fluid reabsorption in the proximal tubules (APRH₂O: 0.50 ± 0.02 vs. 0.64 ± 0.03 mL min^?1 g KW^?1, P < 0.05; FPRH₂O: 58 ± 3 vs. 68 ± 2%, P < 0.05); and (ii) a normal Tm_G. In addition, during baseline clearance measurements neonatally enalapril-treated rats showed increases in urine volume and fractional excretion rates of sodium and potassium, a reduction in urine osmolality, whereas glomerular filtration rate and effective renal plasma flow were unaltered. These results suggest that neonatal ACE inhibition produces an irreversible, but differentiated, abnormality in proximal tubular function. Thus, the development of a normal proximal tubular function in the rat seems to be dependent on an intact renin-angiotensin system, (RAS) neonatally.     

Changes in myocardial capillary diffusion capacity during infusion of vasoactive drugs

The present study investigated how variations in coronary vascular resistance and metabolic demand affected myocardial capillary diffusion capacity. Hearts from Wistar rats were perfused with Krebs-Henseleit-albumin buffer in a Langendorff preparation, where heart rate (HR), contractility (dP/dt_max) and myocardial oxygen consumption (MVO₂) were recorded continuously. Myocardial capillary diffusion capacity was measured as the permeability surface area product (PS) for Cr-EDTA and vitamin B₁₂ by the single injection colorimetric indicator dilution method. After base-line recordings without drugs, angiotensin II + arginine-vasopressin was infused, which increased coronary vascular resistance by 90%, stimulated HR by 11%, decreased dP/dt_max by 21% and reduced MVO₂ by 4%. PS_Cr-EDTA and PS_B12, decreased by 24 and 27%, respectively, leaving the ratio PS_Cr-EDTA/PS_B12 unchanged indicating unaltered capillary permeability. Moreover, the reductions in MVO₂ and PS correlated significantly. During vasodilation: (1) nitroprusside-NA stimulated HR by 7% and decreased dP/dt_max by 14%; (2) adenosine reduced dP/dt_max by 37% and decreased MVO₂ by 9%; and (3) isoproterenol increased HR, dP/dt_max and MVO₂ by 53, 76 and 9%, respectively. However, all three vasodilators reduced PS_Cr-EDTA and PS_B12 in parallel by 7–25% leaving PS_Cr-EDTA/PS_B12 unchanged. Thus, maximal estimated diffusion capacities were obtained during spontaneous coronary vascular tone, most likely reflecting maximal capillary recruitment in the Krebs-Henseleit-albumin perfused heart. The derecruiting effects of the vasoconstrictors were partly overridden by metabolic factors, while the reductions of PS after vasodilation more likely were due to increased heterogeneity in coronary flow.     

Retreatment of endodontic fillings

Abstract— Effects of endodontic retreatment on quality of seal and periapical healing were assessed among 660 previously root-filled roots. The roots were divided into either of two groups according to presence or absence of pathologic alterations in the periapical area. The retreatments, which were carried out by dental students, involved a thorough chemomechanical debridement of the root-canal system aiming to control infection. Following a 2-year observation period 556 roots were reexamined clinically and radiographically. The results showed that root-fillings with technical shortcomings could, following retreatment, be markedly improved as regards effectiveness of seal and distance to the apex. A large number of lumina discernible apical to root-filling could also be treated and filled. Seventy-eight percent of the cases with pathologic lesion present periapically prior to retreatment either completely healed or displayed an obvious size-reduction of the process Retreatments carried out because of technical inadequacies alone were successful in 94% of the cases. It was concluded that renewed endodontic treatment whenever possible is the method of choice when treating defective endodontic fillings complicated with pathologic processes periapically. Apical surgery may be attempted if no signs of healing are apparent following observation.     

The Role of Glucagon,Catecholamines and Cortisol in Counterregulation of Insulin-induced Hypoglycemia in Normal Man

ABSTRACT To study the response of glucose counterregulation to insulin-induced hypoglycemia, six normals were given a 4-hour infusion of insulin (2.4 U/h) ± somatostatin (50 μg/h). Supplementary glucagon (1.5 or 3.0 ng/kg/min) was given in additional experiments. In a separate study, glucagon was supplemented for 4 hours as a constant rate infusion (3.25 ng/kg/min) or at rates stepwise increasing from 1.5 to 5.0 ng/kg/min. Insulin decreased blood glucose by 1.5 mmol/1 and simultaneous suppression of glucagon resulted in a more pronounced hypoglycemia enhancing the adrenaline and Cortisol responses. The hyperglycemic effect of glucagon substitution (3 ng/kg/min) faded out after about 2 hours, whereafter exaggerated adrenaline and Cortisol responses to hypoglycemia were seen. A comparison between the effects of steady state hyperglucagonemia and gradually appearing hyperglucagonemia on the counterregulation of hypoglycemia revealed no significant differencies in glucose, adrenaline and Cortisol responses to insulin. It is concluded that the glycemic effect of glucagon is transient in the hypoglycemic state. When the hepatic responsiveness to this hormone is decreased during hypoglycemia, adrenaline becomes the essential protective factor.     

Subclavian Steal Syndrome: Can the Blood Pressure Difference Between Arms Predict the Severity of Steal

BACKGROUND AND PURPOSE: A side-to-side difference in systolic brachial arterial blood pressure is a common finding in subclavian artery stenosis and is frequently used as a screening tool for subclavian steal syndrome (SSS). It was the goal of this retrospective study to investigate the relationship between different vertebral artery waveform types and the side-to-side difference in systolic blood pressure in patients with sonographically proven SSS. METHODS: The records of 1860 patients from the Neuroultrasound Laboratory between January 2000 and December 2000 were screened for the diagnosis of SSS in the final ultrasound report. In all patients, bilateral brachial arterial blood pressure was measured in a sitting position prior to the ultrasound examination. Vertebral artery waveforms were classified as (1) systolic deceleration, (2) alternating flow, and (3) complete reversal at rest. Blood pressure difference as calculated by normal-side blood pressure minus lesion-side blood pressure was compared with the 3 Doppler waveform types. RESULTS: SSS was found in 51 of 1860 (2.7%) ultrasonography studies of 49 patients (17 men, 32 women; mean age 65.3 +/- 10.5 years). Two patients (4%) had bilateral SSS. In 3 patients (6%), SSS was related to an innominate artery stenosis. Waveform analysis showed a completely reversed flow in 16 (31%), an alternating flow in 24 (47%), and a systolic deceleration in 11 (22%) cases. Systolic blood pressure difference was significantly higher in the complete reversal and alternating groups than in the systolic deceleration group (P < .001). CONCLUSION: Brachial systolic blood pressure difference is related to the severity of SSS and can be used as a screening tool for SSS. However, it performed better in severe steal than milder steal phenomena.     

L-norgestrel and progesterone have different influences on plasma lipoproteins

Twenty-six postmenopausal women who had been on cutaneous oestradiol treatment for 3-6 months were given either 120 micrograms of 1-norgestrel (n = 13) or 300 mg of progesterone (n = 13) sequentially for another 6 months. The concentrations of cholesterol, phospholipids and triglycerides were determined in plasma and in the HDL, HDL2, HDL3, LDL and VLDL fractions before and after one, three and six cycles of progestin treatment. Already after 11 days on 1-norgestrel, the mean HDL cholesterol and the mean HDL phospholipid concentrations were reduced by 15%. The reduction of the HDL-lipids was mainly confined to the HDL2 fraction which was decreased by 25-30%. L-norgestrel also reduced the mean TG concentration both in the VLDL and the combined LDL + HDL fractions. Progesterone gave only minor changes of the plasma lipids and lipoproteins. Reduced HDL, especially HDL2, concentration, as induced by 1-norgestrel, might increase the risk for ischaemic heart disease. Therefore, it seems that, as regards the effects on the lipoproteins, progesterone might be more suitable than the 19-nortestosterone derivative 1-norgestrel for postmenopausal sequential hormonal therapy.     

Variability of Blood Pressure in Ambulatory Hypertensive Patients: Effects of Verapamil on Twice and Thrice Daily Dose Regimens

ABSTRACT The antihypertensive effects of verapamil over 24 hours were assessed on twice and thrice daily dose regimens on 12 patients (25–65 years of age; mean age 50) with essential hypertension (WHO stages I–II) in a randomised, double-blind, cross-over trial. After a dose titration period starting with either verapamil 80 mg tid or 120 mg bid the patients kept their maintenance dose (240, 360 or 480 mg daily) for 4 weeks before crossing over to the other administration schedule. Repeated ambulatory blood pressure (BP) curves were recorded in 10 patients with a non-invasive portable device (Pressurometer III, Del Mar Avionics). The BP reductions (causal BP values) obtained by 2- and 3-dose regimens were of similar magnitude (from 170±19/105±8 on placebo to 140±17/87±7 and to 146±14/88±8 by 2- and 3-dose respectively). Analyses of BP curves revealed close similarity in profiles on the two dose regimens, although DBP was significantly (p<0.05) lower by 3-dose as compared to 2-dose regimen during the period 0.00–2.59 a.m. Long-term (circadian rhythm) and short-term variability did not differ between the regimens. Despite the slight difference in DBP curves after midnight, the overall impression is that verapamil given both twice and thrice daily provides adequate BP control throughout 24 hours.