Aluminium speciation in cerebrospinal fluid of acutely aluminium-intoxicated dialysis patients before and after desferrioxamine treatment; a step in the understanding of the element's neurotoxicity

Background: The association between aluminium and dialysis encephalopathy and deterioration of the neurological state during desferrioxamine treatment of dialysis patients is well established. At present little is known about the speciation and the mechanisms underlying the element's neurotoxicity. Methods. Aluminium speciation was performed in cerebrospinal fluid samples of acutely aluminium-intoxicated dialysis patients using a recently developed high-performance liquid chromatographic/electro-thermal atomic absorption spectrometric hybrid method. Results: Baseline cerebrospinal fluid aluminium levels of samples taken shortly after the intoxication were low but elevated (5.0±2.0 &mgr;g/l, n=3) as compared to subjects with normal renal function (<1 &mgr;g/l). In contrast to the situation noted in serum and to the iron speciation in cerebrospinal fluid, aluminium was not bound to transferrin but appeared as two distinct compounds, the main fraction eluting at the elution volume of aluminium citrate/silicate. The second compound was not identified. Forty-four hours after desferrioxamine administration the cerebrospinal fluid aluminium levels had increased up to a concentration of 10.3±2.5 &mgr;g/l (n=3). This was accompanied by a change in the speciation profile with aluminium appearing at the elution volume of aluminoxamine. Conclusion: Our findings may contribute to a better understanding of the neurotoxic effects of aluminium and its desferrioxamine chelate in dialysis patients.     

Content of HSP70 in rats with hereditary stress-induced arterial hypertension

Sensitivity of normotensive Wistar rats and NISAG rats (with hereditary arterial hypertension) to heat stress is compared at the organism and cell levels. High temperature sensitivity of NISAG rats correlates with a low content of the main heat shock protein HSP70. This relationship can serve as a biochemical marker of predisposition to arterial hypertension. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 171–173, August, 1997     

Evidence for the presence of a type III secretion system in diffusely adhering Escherichia coli (DAEC).

Diffusely adhering Escherichia coli (E. coli) strains (DAEC) represent a potential cause of diarrhoea in infants, and the detection of type three secretion system (TTSS) genes in DAEC would substantiate their pathogenic nature. In this work, four isolates of DAEC, recovered from stools of diarrhoeic children, were analysed by PCR, in order to detect the presence of TTSS genes. Primers targeted to the escC, escJ, escN and escV, some of the most conserved TTSS genes in enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), were used in order to verify the occurrence of homologous genes in our DAEC isolates. By this approach, we were able to characterise DNA fragments corresponding to putative escJ and escN genes in all DAEC isolates. Furthermore, DNA fragments homologous to the escC and escV genes were also amplified from all isolates. Besides the similarity found among the DAEC esc homologues with EPEC and EHEC esc genes, the nucleotide sequence analysis of the flanking regions of the amplified DNA fragments suggests that the putative DAEC esc genes are organised in the same manner as observed in EPEC and in EHEC strains. The results described here provide strong evidence for the presence of a TTSS in the DAEC strains analysed, implicating a pathogenic nature of these isolates.     

Possible anatomical base of snoring

Variations of the medial and inferior choanal limits may facilitate snoring. These are: 1) short vomer without crista choanalis vomeris and adaptational formations, 2) extremely concave posterior margin of the hard palate leading to disproportion between the muscular and aponeurotic part of m. tensor veli palatini and hence to a flabby soft palate especially during sleep, and 3) neonatal relation of the height and width of the choane resulting in a very large choanal region instead of relative reduction of choanal width compared to its increasing height. All these variations result in a flabby soft palate especially during sleep and may lead to formation of whirles of inspired air and snoring.     

An evaluation of two signal-processing hearing aids

Various forms of signal processing are used in modern ASP hearing aids. The present study investigated the relationship between sentence recognition ability and two types of signal processing used in commercially available hearing aids. Results indicated a significant improvement in sentence recognition ability employing an instrument with adaptive compression (variable release time) versus an instrument with an adaptive high-pass filter with short attack and release times. Data were obtained for a single-talker competing message at several message-to-competition ratios. The adaptive compression system may prove to be beneficial to hearing-impaired listeners in certain background noise environments.     

How to assess fetal metabolic acidosis from cord samples.

The degree of metabolic acidosis at birth has been calculated in cord artery and vein samples from 21 term fetuses with cord artery pH less than 7.20. The aim of the study was to compare base deficit values calculated from either Siggaard-Andersen alignment nomogram (BD blood) or the Acid-Base chart (BD extra cellular fluid, BDecf). BDblood was found to be consistently higher in the cord artery as compared with BDecf, 13.2 +/- 3.5 and 9.9 +/- 2.9 mmol/l (Mean +/- SD), respectively. A significant correlation was found between cord artery PCO2 and BDblood whereas BDecf appeared unaffected by PCO2. In cases with cord entanglement BDecf a-v differences were increased to 3.4 +/- 2.3 mmol/l as compared with the small a-v difference noted in acidotic cases without cord entanglement, 1.1 +/- 1.25 mmol/l. It is speculated that with acutely emerging, intermittent asphyxia due to cord compression, a cord artery and vein difference in metabolic acidosis may exist and where the vein captures the basal level and the artery the acute changes. It is concluded that BDecf in both cord artery and vein add valuable information on the mechanisms behind metabolic acidosis.