Reduction in sodium chloride intake: effects on urinary Na, K and aldosterone output in healthy free-living adults

Eleven healthy free-living adults (six women, five men) weighed and recorded all food and drink consumed and collected all urine for two non-consecutive 7-day periods whilst eating their usual diet (Period 1) and attempting to reduce salt intake (Period 2). Bread (including pitta bread) provided on average a quarter of total Na intake of subjects in Period 1 so that wholemeal bread made without added salt was made available in Period 2. All subjects achieved substantial reductions (mean 65%) in Na intake in Period 2 with no change in K intake so that the Na:K molar ratio fell from 1.3 to 0.5. Urinary Na output closely followed intakes and there was a large increase (mean 11.2 μg/d) in aldosterone excretion with a non-significant increase in K output. Simple linear relationships which allow prediction of Na and K intake from the more easily measured urinary output were derived.     

Subclinical pulmonary oedema and intermittent haemodialysis

It has been postulated that patients with chronic renal failure,even in the absence of cardiopulmonary symptoms, accumulateinterstitial pulmonary fluid, which is removed by haemodialysis.To test this hypothesis we used the indocyanine green (ICG)-heavywater double indicator dilution method to measure lung water,cardiac output, and central blood volume in relation to haemodialysis.Ten uraemic patients, without cardiopulmonary symptoms, wereinvestigated at the beginning and end, and 2 h after, a regulardialysis session. A group of 18 surgical patients about to undergoelective abdominal surgery served as controls. Despite normalgas exchange, central blood volume, and cardiac output at thestart of dialysis the mean (SD) lung water was significantlyhigher than in the control group [4.8 (0.9) compared with 3.6(0.7) ml/kg, P<0.001]. There was no correlation between weightgain between sessions of dialysis and the magnitude of lungwater at the start of dialysis. Lung water decreased (P <0.001)to the level of the control group in response to dialysis. Therewas no correlation between weight loss and reduction in lungwater induced by dialysis. In conclusion, we have verified thepresence of subclinical pulmonary oedema which was removed bydialysis in a group of patients with established renal failure.The variations in lung water cannot be explained by hydrostaticmechanisms alone.     

急性肾功能衰竭的治疗进展

目的：探讨急性肾功能衰竭的治疗。方法：复习有关急性肾功能衰竭的治疗文献，作一总结。结果：使用人工合成三肽序列（RGD）的多肽、生长因子、心房利钠因子和人工肾小管治疗急性肾功能衰竭都取得了较好的疗效。结论：这些新的治疗可望改善急性肾衰的预后和降低死亡率。     

Presynaptic α2-adrenoceptor-mediated modulation of norepinephrine release from vascular adrenergic neurons in reduced renal mass salt hypertensive rats

The present study was designed to investigate the presynaptic alpha 2-adrenoceptor function to inhibit norepinephrine (NE) release in blood vessels of reduced renal mass salt hypertensive rats (Na-loaded HT). Isolated perfused mesenteric vasculatures were prepared from Na-loaded HT and normotensive control rats (NT-control), and the NE release and vascular responsiveness were examined. Periarterial nerve stimulation caused a significantly greater release of NE and pressor responses in Na-loaded HT than in NT-control. Yohimbine, a potent alpha 2-adrenoceptor antagonist, demonstrated the facilitatory effects on NE release during nerve stimulation. The effects were significantly attenuated in Na-loaded HT compared with NT-control. These results demonstrate that vascular sympathetic nervous activity might be enhanced in Na-loaded HT. Furthermore, the increased NE release from vascular adrenergic neurons in Na-loaded HT could partially depend on impaired presynaptic alpha 2-adrenoceptor-mediated modulation, which might contribute to the pathogenesis and maintenance of this form of salt-dependent hypertension.     

Taurine entry into perilymph of the guinea pig

Taurine is a β-aminosulfonic acid and is a ubiquitous amino acid whose role in the cochlea is not well established. In this study, its entry from blood into perilymph was investigated in the guinea pig as animal model. The penetration rate of [³H]taurine (molecular weight 125) into the perilymph of the scala vestibuli was measured 1 and 2 h after the intravenous infusion of [³H]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma at 36 ± 4.7% (n = 5) after 1 h and 43 ± 5.6% (n = 5) after 2 h. Compared to the penetration rate of urea (molecular weight 60) and mannitol (molecular weight 186) reported previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is suggested. Received: 30 July 1997 / Accepted: 15 January 1998     

Metabolic myocardial viability assessment with iodine 123-16-iodo-3-methylhexadecanoic acid in recent myocardial infarction: Comparison with thallium-201 and fluorine-18 fluorodeoxyglucose

The best test presently available to ascertain residual viability within an infarct-related area involves the use of fluorine-18 fluorodeoxyglucose (FDG) to detect the persistence of some cellular metabolism. Rest reinjection of thallium-201 is a less accurate alternative but is easy to perform. Iodinated fatty acids, which are used with standard gamma cameras, are proposed as markers of cellular metabolism. This study was performed to assess the value of 16-iodo-3-methyl-hexadecanoic acid (MIHA) as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and to evaluate its contribution compared with the²⁰¹Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection²⁰¹T1 imaging, rest MIHA imaging and glucoseloaded FDG imaging were performed in 22 patients with recent myocardial infarction. Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused (relative uptake <0.75 of maximum uptake on stress²⁰¹T1 imaging), 177 of which were severely hypoperfused (relative uptake <0.50). Receiver operating characteristic (ROC) curves for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a)²⁰¹T1 activity during exercise, redistribution and reinjection and (b) MIHA up-take, using the two FDG thresholds most commonly considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that²⁰¹T1 reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85 and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively;P<0.05 vs other tests). The global predictive values of MIHA and²⁰¹T1 reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold (NS). When only the 177 severely hypoperfused segments were considered,²⁰¹T1 reinjection remained the most accurate test (accuracy 0.84 at the 0.50 FDG threshold and 0.82 at the 0.60 FDG threshold), while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold,P<0.05 vs²⁰¹T1 reinjection). In all circumstances, MIHA was less specific than²⁰¹T1 reinjection for the detection of metabolic viability. In conclusion, in patients with recent myocardial infarction, MIHA accurately detects the persistence of metabolic viability, but is not superior to²⁰¹T1.     

Pattern of renal dysfunction in analgesic nephropathy--comparison with glomerulonephritis.

Comprehensive renal function tests were performed in 84 patients with analgesic nephropathy, 33 glomerulonephritis patients matched for creatinine clearance, and 30 control subjects. A system of 1-day renal function tests including urine microscopy, creatinine clearance, phenolsulphonphthalein excretion, urine concentration and acidification, and electrolyte excretion, was used. Patients with analgesic nephropathy were found to have significant sterile pyuria and haematuria, even those with mild renal insufficiency, significantly reduced concentrating ability and a distal acidifying defect, and a tendency to impaired sodium conservation. These function defects are consistent with the primary lesion of renal papillary necrosis in analgesic nephropathy; the detection of these defects have implications in patient management.     

Urinary protein excretion and renal function in young people with diabetes mellitus.

To detect early renal involvement in young diabetic patients (IDDM), urinary protein excretion and renal function were examined in 110 patients aged 5.9-25.0 years. Clearances of inulin and PAH were determined as well as albumin (Alb), IgG, N-acetyl-beta-D-glucosaminidase (NAG) and creatinine (Cr) excretion rates (UV). The patients were grouped according to IDDM duration (2- less than 5, 5-10 and greater than 10 years) and albumin excretion rate (non-albuminuria less than 20, microalbuminuria 20-200, and albuminuria greater than 200 micrograms/min per 1.73 m2). Four patients had overt albuminuria, 17 microalbuminuria (equally distributed among the duration groups). Grouped according to albumin excretion rate, the mean GFR was increased in those without albuminuria but 'normalized' in patients with microalbuminuria/albuminuria. Grouped according to albumin excretion rate and the duration of the disease, the non-albuminuric patients with IDDM for greater than 10 years had a lower GFR than those with a shorter duration of IDDM. The patients with microalbuminuria/albuminuria and IDDM for less than 5 years had a reduced GFR. Patients with increased NAG excretion rate had lower Na excretion rate, lower fractional Na excretion and greater creatinine excretion than those with normal NAG excretion. Albumin excretion correlated with IgG excretion, but also with NAG excretion. Our results suggest that early albuminuria in IDDM is of both glomerular and tubular origin. The hyperfiltration declines with increasing albumin excretion but also with the duration of the disease.