High plasma adenine concentration in chronic renal failure and its relation to erythrocyte ATP

BACKGROUND: Concentration of plasma adenine has been found to increase in chronic renal failure (CRF). The aim of the present study was to evaluate whether high plasma adenine concentration contributes to the elevated ATP in erythrocytes of patients with CRF. METHODS: Three groups of patients with CRF were studied: (A) 30 patients with different degree of CRF; (B) 11 patients on hemodialysis, and (C) 12 patients after successful renal transplantation. Concentrations of plasma adenine and erythrocyte adenine nucleotides were measured in groups A, B and C. Furthermore, adenine incorporation into erythrocyte adenine nucleotide pool was measured in group A. RESULTS: A positive correlation between plasma adenine and creatinine concentrations was found in CRF as well as between plasma adenine and erythrocyte ATP. Furthermore, positive correlation was evident between the rate of adenine incorporation into erythrocyte adenine nucleotide pool and the severity of CRF. A significant reduction in both plasma adenine and erythrocyte ATP was observed immediately following hemodalysis, but 2 days later, high predialysis plasma adenine and erythrocyte ATP concentrations were restored. Following successful renal transplantation erythrocyte ATP and plasma adenine concentrations reached control values. CONCLUSION: Our results provide evidence that plasma adenine concentration increases in parallel to the progress of the disease and that it could be responsible for the increase in erythrocyte ATP of patients with CRF.     

The role of platelet activating factor (PAF) in physiology and pathology of the central nervous system

This review describes the role of platelet activating factor (PAF) in the central nervous system injury. Cerebral ischaemia, traumatic injury of central nervous system, metabolic, toxic and degenerative neuropathy, and also the increase in Ca2+ concentration in the cell, are strong stimulators of PAF synthesis and its release from cell membranes. Neurons, glial and microglial cells, monocyte cell populations, macrophages and endothelial cells of blood vessels are the targets of platelet activating factor. The release of PAF leads to ischaemia of nervous tissue, acute traumatic or nontraumatic injuries, degenerative and metabolic nervous system disorders in adults. The use of PAF receptor antagonists prevents partially cell injury in central nervous system and leukocyte adhesion to endothelial cells.     

Norepinephrine transporter gene polymorphism is not associated with susceptibility to alcohol dependence

Abnormalities in monoamine neurotransmission have been implicated in the pathogenesis of alcoholism, mood disorders and schizophrenia. Murine norepinephrine transporter gene (NET) has been mapped to a region on chromosome 8 where a quantitative trait locus for ethanol sensitivity. Therefore we tested whether norepinephrine transporter (NET) gene variants confer susceptibility to either alcohol dependence or severe alcohol withdrawal symptoms. There is a highly polymorphic silent G1287A mutation in the NET gene. In our study 157 alcoholics and 185 healthy unrelated matched control subjects were analyzed for a silent G1287A mutation. No significant differences in allele and genotype distribution between control subjects f(A)=0.33 and alcoholics f(A)=0.29 were found. No significant results were found in more homogenous subgroups, i.e. alcoholics with severe alcohol withdrawal (seizures, delirium), early onset age<26 nor dependent patients with positive familial history of alcoholism. These results suggest that the NET gene polymorphism in exon 9 accession number: mRNA: NM_001043, genomic contig.: NT_019610, is unlikely to be involved in the susceptibility to alcoholism and severe alcohol withdrawal.     

The influence of saturated fatty acids on prostaglandin synthetase activity

Saturated fatty acids (C₁₀, C₁₂, C₁₄, C₁₆ and C₁₈) as well as lauryl sulphate inhibit the microsomal prostaglandin synthetase of bovine seminal vesicles (BSVM). The most potent inhibitors are lauryl sulphate, lauric and myristic acids ($\text{ic}{}_{50}\text{= 250 μ}\text{M}$). The last two acids are strong ligands to hydrophobic sites of albumin. Indomethacin is also strongly bound to the hydrophobic sites of albumin; however, indomethacin inhibits the generation of prostaglandins at a concentration approximately 2500 times lower than the most active fatty acid inhibitor. The inhibitory action of fatty acids and indomethacin on prostaglandin synthetase activity has been measured by estimation of either PGE₂ or malondialdehyde, which are generated from arachidonic acid by BSVM. The former procedure is more reliable and reproducible than the latter.     

The evolution of epidemiology and clinical characteristics of laryngeal and hypopharyngeal carcinoma in Poland from 1991 to 2001

On the base of retrospective analysis of 12,888 cases of carcinoma of larynx and hypopharynx, diagnosed in 19 ENT Departments in Poland from 1991 to 2001, the assessment of basic epidemiological data, including the localization of tumor and stage of local and clinical advancement of the disease at the time of diagnosis has been conducted. In analyzed period of 11 years the trends to change of the mentioned above parameters has been examined. The significant increase of female patients in this period was observed, with average proportion M:F = 8:1. The glottis localization of carcinoma dominated (47.6%), followed by supraglottis (40.8%) and pyriform fossa (7.8%), with significant increase of pyriform fossa tumors in the analyzed period of 11 years. In the majority of cases the carcinoma of larynx and hypopharynx was diagnosed in the advanced stage (T3 + T4) of local disease, with the highest percentage in localization within the pyriform fossa (81.0%), and the lowest percentage in glottis tumors (45.6%). The regional lymph nodes metastases has been diagnosed in 46.7% of the analyzed group, with the highest percentage in tumors localized in pyriform fossa (82.9%), and the lowest percentage in tumors of glottis localization (33.1%). In the 11 years time the significant drop down of N0 cases and tendency to increase of N2 and N3 in the supraglottis localization of tumor. The distant metastases in the analyzed group at the time of diagnosis has been registered in 2.0%, with the highest percentage in posterior pharyngeal wall (7.6%) and pyriform fossa (7.4%). The authors postulate the renewal of prospective study on epidemiology, clinical characteristics and treatment results of larynx and hypopharynx carcinoma in Poland.