A sensitive non-radioactive assay for pyrimidine nucleoside phosphorylase using reversed-phase high performance liquid chromatography

A new sensitive assay for pyrimidine nucleoside phosphorylase using non-radioactive substrates is described. With the natural substrate uridine (UR) and the analog, 5'-deoxy-5-fluorouridine (5'dFUR) conditions have been optimized to measure the product formation with reversed-phase high-performance liquid chromatography. Using automated injection large series of samples may be analyzed. The assay for UR phosphorylase appeared to be comparable to existing methods with radiolabeled UR as substrate regarding sensitivity and linearity. The assay has been used to measure kinetic parameters for 5'dFUR and UR in two cell lines from intestinal origin.     

Effects of oral N-acetylcysteine on plasma homocysteine and whole blood glutathione levels in healthy, non-pregnant women.

Oral N-acetylcysteine supplementation in nine young healthy females induced a quick and highly significant decrease in plasma homocysteine levels and an increase in whole blood concentration of the antioxidant glutathione. N-acetylcysteine impresses as an efficient drug in lowering homocysteine concentration and might be beneficial for individuals with hyperhomocysteinemia who are at increased risk of cardiovascular disease.     

Glial cell line-derived neurotrophic factor-dependent recruitment of Ret into lipid rafts enhances signaling by partitioning Ret from proteasome-dependent degradation

The receptor tyrosine kinase (RTK) Ret is activated by the formation of a complex consisting of ligands such as glial cell line-derived neurotrophic factor (GDNF) and glycerophosphatidylinositol-anchored coreceptors termed GFRalphas. During activation, Ret translocates into lipid rafts, which is critical for functional responses to GDNF. We found that Ret was rapidly ubiquitinated and degraded in sympathetic neurons when activated with GDNF, but, unlike other RTKs that are trafficked to lysosomes for degradation, Ret was degraded predominantly by the proteasome. After GDNF stimulation, the majority of ubiquitinated Ret was located outside of lipid rafts and Ret was lost predominantly from nonraft membrane domains. Consistent with the predominance of Ret degradation outside of rafts, disruption of lipid rafts in neurons did not alter either the GDNF-dependent ubiquitination or degradation of Ret. GDNF-mediated survival of sympathetic neurons was inhibited by lipid raft depletion, and this inhibitory effect of raft disruption on GDNF-mediated survival was reversed if Ret degradation was blocked via proteasome inhibition. Therefore, lipid rafts sequester Ret away from the degradation machinery located in nonraft membrane domains, such as Cbl family E3 ligases, thereby sustaining Ret signaling.     

Mammographic evaluation of the postsurgical and irradiated breast

Mammography is important in women who elect lumpectomy and radiation therapy for breast carcinoma: to record the preoperative state, to assess the completeness of resection, and to detect recurrences and second primaries. Mammography of these patients, however, is difficult since surgery and irradiation may cause changes simulating carcinoma. This article describes the findings in the postsurgical and irradiated breast and the difficulty of differentiating the changes from recurrent carcinoma. It also illustrates the findings in recurrences and second primaries.     

99Tcm-HMPAO labelled leucocytes: comparison with 111In-tropolonate labelled granulocytes

The lipophilic complex, 99Tcm-hexamethylpropyleneamine oxime (HMPAO) is an efficient leucocyte label, and labels granulocytes with more stability than mononuclear leucocytes. The recovery of 99Tcm-HMPAO granulocytes, expressed as the percentage of injected granulocyte-associated activity circulating as granulocyte-associated activity 40-45 min after injection, was 37% (S.E. 3%), similar to the recovery of 111In-labelled granulocytes isolated and labelled in plasma using tropolone. The T1/2 of 99Tcm-HMPAO labelled granulocytes in blood was 4.4 h (S.E. 0.4 h), less than that of 111In-labelled granulocytes, although when a correction was made for 99Tcm elution, it was 6.4 h. The initial biodistribution of 99Tcm-labelled leucocytes was similar to 111In-labelled granulocytes, with a rapid initial lung transit, prominent splenic activity, bone marrow activity and minimal hepatic activity, although, unlike 111In, 99Tcm activity was also seen in urine, occasionally in the gallbladder, and, from about 4 h, consistently in the colon. Bone marrow activity was particularly prominent with 99Tcm. About 6% of 99Tcm was excreted in the faeces up to 48 h after injection, and about 17% in urine up to 24 h. The time-activity curves of reticuloendothelial activity up to 24 h were broadly similar for the two labelled cell preparations, and the differences that were observed can be explained on the basis of a higher rate of 99Tcm elution. Clinical information given by the two agents was similar in 27 of 30 patients who received both. Of the three who gave different information, one received 111In-labelled granulocytes which were considered to be functionally suboptimal and two, with inflammatory bowel disease, showed different distributions of abnormal bowel activity. We conclude that with respect to granulocyte kinetics and clinical data, 99Tcm-HMPAO labelled leucocytes are comparable with 111In-tropolonate labelled granulocytes.     

Flunarizine and R 56865 suppress veratridine-induced increase in oxygen consumption and uptake of 45Ca2+ in rat cortical synaptosomes.

The effect of the anti-ischemic compounds flunarizine and R 56865 on the veratridine-induced uptake of Ca2+ and Na+ was observed in cortical synaptosomes in the rat. The veratridine-induced uptake of Na+ and Ca2+ was determined by means of a measurement of synaptosomal oxygen consumption and a method for the uptake of 45Ca2+, respectively. Veratridine (10(-5) M) was found to induce a 3-fold increase in synaptosomal oxygen consumption (uptake of Na+) and uptake of 45Ca2+, both of which were inhibited by tetrodotoxin (10(-5) M). Nitrendipine (10(-5) M) and omega-conotoxin (5 x 10(-7) M) were ineffective on the veratridine-induced response. Nimodipine (10(-5) M) suppressed the veratridine-induced uptake of 45Ca2+ but also diminished the unstimulated uptake of 45Ca2+. The veratridine-induced uptake of Na+ was not influenced by nimodipine. Flunarizine (3 x 10(-6)-10(-5) M), as well as R 56865 (10(-6)-10(-5) M), attenuated the veratridine-induced uptake of both Na+ and 45Ca2+. In conclusion, the veratridine-induced uptake of Na+ and 45Ca2+ was shown to be closely correlated to the activity of Na+ channels but not to voltage-operated Ca2+ channels. Secondly, flunarizine and R 56865 seemed to evoke their effects by interfering with the permeability of Na+ channels. Since veratridine-induced uptake of Na+ and Ca2+ shares some similarities with ischaemia-induced uptake of Na+ and Ca2+, it is proposed, that flunarizine and R 56865 exert their anti-ischaemic effects by reducing ischaemia-induced Na+ and Ca2+ load, probably by inhibiting a TTX-sensitive Na+ channel.     

Incorporating the affective component into an AIDS workshop

Caring for persons infected with the human immunodeficiency virus (HIV) and with acquired immunodeficiency syndrome (AIDS) will be a growing challenge for nurses in the years to come. It the nursing profession is to meet this challenge, continuing education will be essential. This article presents an approach to using a range of community and academic resources in the provision of continuing education. The 1-day program described includes updated information on HIV etiopathogenesis, clinical spectrum, epidemiology, transmission, prevention, and research, and gives participants an opportunity to explore their feelings and attitudes toward providing care for persons with HIV.     

Therapieresistente Lumboischialgie durch überlangen Dornfortsatz des LWK 5

Ohne ZusammenfassungLiebe Kolleginnen und Kollegen!Wenn Sie eine interessante Falldarstellung haben, schicken Sie bitte Ihren Vorschlag mit Beschreibung und Bildmaterial an die Redaktion.Prof. Dr. W. Beyer, Bad FüssingRedaktion Bild und Fall