A novel transcriptome subtraction method for the detection of differentially expressed genes in highly complex eukaryotes.

We have designed a novel transcriptome subtraction method for the genome-scale analysis of differential gene expression in highly complex eukaryotes, in which suppression subtractive hybridization (SSH) is performed first to enrich the target and, after exchange of adapters, negative subtraction chain (NSC) is then used to eliminate the remaining background. NSC evolved from differential subtraction chain (DSC). We designed novel adapters which make the subtraction system more robust. SSH and NSC were then combined to successfully detect differentially expressed genes in Solanum. The combined technique improves qualitatively upon SSH, the only commercially available transcriptome subtraction system, by detecting target genes in the middle abundance class, to which most differentially expressed genes in highly complex eukaryotes are expected to belong. The main advantage of the combined technique with SSH/NSC is its ability to isolate differentially expressed genes quickly and cost-efficiently from non-standard models, for those microarrays are unavailable.

Influence of the renal endothelin system on the autoregulation of renal blood flow in spontaneously hypertensive rats.

The renal endothelin (ET) system has been claimed to play an important role in the regulation of renal blood flow (RBF) and sodium excretion in primary hypertension. The aim of the present study was to investigate the contribution of the endogenous ET system in the autoregulation of total RBF, cortical blood flow (CBF), pressure-dependent plasma renin activity (PRA) and pressure natriuresis in spontaneously hypertensive rats (SHR) by means of the combined (A/B) ET-receptor antagonist, bosentan. In anesthetized rats, RBF was measured by transit-time flow probes and CBF by laser flow probes. During the experiments, the rats received an intrarenal infusion of either bosentan (1 mg/kg/h) or vehicle. Renal perfusion pressure (RPP) was lowered in pressure steps of 5 mm Hg with a servo-controlled electropneumatic device via an inflatable suprarenal cuff. Bosentan had no effect on resting RPP, CBF, PRA and renal sodium excretion, whereas RBF was lowered by 30% (p < 0.05). Furthermore after bosentan the rats revealed a complete loss of RBF autoregulation. In contrast no changes in autoregulation of CBF, pressure-dependent PRA and pressure natriuresis were observed. Our findings demonstrate a significant impairment in total RBF autoregulatory ability during renal ET-receptor blockade which is not confined to the cortical vessels. These data suggest that the renal ET system plays an important role in the dynamic regulation of renal blood flow in SHR.

Effect of low-protein diet on renal function: are there definite conclusions from adult studies?

Low-protein diets have been used for roughly a century in order to alleviate uraemic symptoms and to delay progression of chronic renal failure (CRF). Currently a number of different low-protein diets are used, supplying either 0.6 g protein/kg body weight or 0.3-0.4 g supplemented with amino-acids or keto-acids. Single centre trials have attempted to demonstrate the efficacy of these diets in slowing down the progression of CRF. The results from these trials are, however, sometimes inconclusive, showing either a high efficiency of the low-protein diet or no efficiency at all. Conclusive data from multicentre trials, however, are not yet available. A crucial point in analysing the efficacy of low-protein diets is the degree of compliance with the protein restriction. Today, the data available indicate that sometimes only a poor degree of compliance is achieved both in single and in multicentre trials.

Muzolimine-induced severe neuromyeloencephalopathy: report of seven cases.

We report on 7 patients (2 women, 5 men) with chronic renal failure, who developed under a high dosage of the new diuretic muzolimine (range 240 to 1440 mg per day) fatal neuromyeloencephalopathy. Clinical neurophysiological and neuroradiological findings and finally neuropathological studies in 2 patients resembled those found in vitamin-B12-deficiency-syndrome with a predominant affection of the spinal posterior column and the corticospinal tracts. The first neurological symptoms like paraesthesia, severe hyperpathia of the legs and mild to heavy spinal ataxia occurred after an average time of treatment of 78 days and a mean dosage of 52 g. The most progressive neurological deficits like severe tetraspastic paresis, were seen only in the nondialytic renal insufficient group (3 patients), while the others had a more benign course of the disease. This lead to the hypothesis of a partially dialysable toxic metabolite of muzolimine. After a follow-up of more than 2 1/2 years no significant recovery was seen in these cases.

[Neuromyeloencephalopathy caused by high-dose muzolimine medication in patients with renal failure]. / Neuromyeloenzephalopathie (NME) unter hochdosierter Muzolimin-Medikation bei niereninsuffizienten Patienten.

We report on 7 patients suffering from chronic renal failure (2 females, 5 males; aged 35-75 (phi 53.5) years) who showed severe neuromyeloencephalopathy (NME) after high doses of a new Henle's loop diuretic, Muzolimine. The temporal and phenomenological development of these systems was strikingly parallel. The neurological deficit was revealed on neurophysiological, neuroradiological and in 2 cases on neuropathological tests (gross demyelinisation of the posterior column, mainly of the fasciculus gracilis, less in the lateral corticospinal tract and in some spinal roots). The critical drug dose for first neurological impairment was 52 g on average; at this point the patients had been treated for 78 days. The maximal daily dose was 1.440 mg. Dominant clinical features were pallhypaesthesia, ataxia, signs of peripheral neuropathy in combination with hyperreflexia and progressive para- to tetraspastic paresis. Constellation of symptoms, course of disease and findings of additional investigations, especially those of neuropathology, very much resemble Vitamin B12 deficiency and SMON-(Subacute Myelo Optic Neuropathy) syndrome. The rare entity of Muzolimine-NME is discussed in respect to other endogenous and exotoxic neuromyelopathies. We present the hypothesis of a toxic, partially dialysable metabolite of Muzolimine.

Does a low protein diet really slow down the rate of progression of chronic renal failure?

In this paper we present evidence from data obtained by different study groups, indicating that a low protein diet slows down the rate of progression of chronic renal failure. These data also demonstrate that the delay of progression is highly dependent on the underlying renal disease. In absolute terms, patients suffering from polycystic kidney disease experienced most benefit from a low protein diet, while in relative terms, the natural course of the renal disease of patients suffering from chronic glomerulonephritis is significantly more delayed than in other disease groups. Furthermore, a vegetarian diet seems to be superior to a meat-containing diet. Thus, we conclude that there are sufficient data from the literature to suggest that a low protein diet delays the progression of chronic renal failure.