Recombinant Sendai viruses with L1618V mutation in their L polymerase protein establish persistent infection, but not temperature sensitivity

The Sendai virus pi strain (SeVpi) isolated from cells persistently infected with SeV shows mainly two phenotypes: (1) temperature sensitivity and (2) an ability of establishing persistent infection (steady state). Three amino acid substitutions are found in the Lpi protein and are located at aa 1088, 1618, and 1664. Recombinant SeV(Lpi) (rSeV(Lpi)) having all these substitutions is temperature sensitive and is capable of establishing persistent infection (steady state). rSeVs carrying the fragment containing L1618V show both phenotypes. rSeV(L1618V), in which leucine at aa 1618 is replaced with valine, has the ability of establishing persistent infection, but is not a temperature-sensitive mutant, indicating that the ability of a virus to establish persistent infection can be separated from temperature sensitivity. The amino acid change at 1618(L-->V) coexisting with aa 1169 threonine is required for acquirement of a temperature-sensitive phenotype. Three amino acid substitutions are also found in the Ppi protein, but rSeV(Ppi) does not show these phenotypes.     

Human myeloma light chains with increased molecular weight: high frequency among lambda chains

The discovery of a human myeloma protein comprising a kappa L-chain with an increased mol. wt of 30,000) (Bouvet et. al., 1980) prompted investigations on the incidence of such heavier L-chains among other human myeloma proteins. In 105 samples examined, 34 were found to have L-chains heavier than normal (23,000-24,000), ranging from 25,000 up to 31,000, and five of lighter mol. wt (21,000-22,000). These mol. wt abnormalities were detected by electrophoresis in sodium dodecyl sulfate 10% polyacrylamide gels (SDS-PAGE) after reduction with 2-mercaptoethanol. The mol. wt of three of the heavier kappa or lambda chains was also estimated by filtration through a Sephadex G100 column and by sedimentation equilibrium. All three methods indicated a mol. wt increase of about 15-25% as compared with the usual mol. wt. The distribution of the high mol. wt chains among all L-chains examined was found to be 11 out of 62 kappa chains (17.7%) and 23 out of 43 lambda chains (53%) (P less than 0.001). A preferential association of such L-chains with H-chains producing multiple bands in SDS-PAGE (P less than 0.01) and an association between multiple L-chain and multiple H-chain band (P less than 0.05) were also observed. In contrast, no abnormal L-chain was found in immunoglobulins from normal subjects. Spontaneous degradation of the normal H-chains sometimes yielded fragments of 30,000 mol. wt. These fragments were easily distinguishable from abnormal L-chains. The nature of extra mol. wt in heavy L-chains was investigated for the presence of carbohydrate moiety. Four large and three normal size L-chains were examined for amino-sugar and sialic acid content. A small amount (one residue per molecule) of amino-sugar was detected only in two normal and two heavy L-chains, whereas sialic acid was only found in the heaviest (27,000-30,000) L-chains (Lh) and in small percentage (one or two residues per molecule). Total sugar estimation in one Lh chain indicated a proportion not exceeding three or four residues per L-chain (mol. wt 1,000) and this is insufficient to explain the 15-25% (3,600-6,000) mol. wt increase. It is therefore possible that, at least in some heavy myeloma L-chains, an additional peptide is expressed. Whatever the nature of the increase it would be of interest to elucidate whether this is a marker of malignant process or of an intermediate step of normal Ig synthesis.     

Immunocytochemical distribution of S-100 protein in patients with Down's syndrome

Summary The immunohistochemical distribution of S-100 protein in patients with Down's syndrome was investigated as part of a study aimed at ascertaining a possible involvement in the syndrome (trisomy 21) of this protein, which has recently been shown to be coded in chromosome 21. No appreciable differences in the cell distribution of the antigen could be observed between patients with Down's syndrome and normal subjects. The possibility of an overexpression or abnormal expression of the molecule as a consequence of chromosome 21 triplication, not detectable by immunocytochemical methods alone, remains to be investigated.Supported in part by grants from Consiglio Nazionale delle Ricerche and Ministero della Pubblica Istruzione to F. M. and L. L.     

Prejunctional inhibition of sympathetically evoked pupillary dilation in cats by activation of histamine H3 receptors

Summary Frequency-dependent pupillary dilations were evoked by electrical stimulation of the pre- or post-ganglionic cervical sympathetic nerve (sympatho-excitation) or the hypothalamus (parasympatho-inhibition) in sympathectomized anesthetized cats. Systemic administration of the selective histamine H₃ receptor agonist (R)--methylhistamine (RMeHA) produced a dose-dependent depression of mydriasis due to direct neural sympathetic activation but had no effect on responses elicited by parasympathetic withdrawal. The histamine H₂ receptor agonist, dimaprit, was inactive. RMeHA was much more effective in depressing sympathetic responses obtained at lower frequencies when compared to higher frequencies of stimulation.Responses evoked both pre- and postganglionically were inhibited by RMeHA. This peripheral sympathoinhibitory action of RMeHA was antagonized by the histamine H₃ receptor blocker thioperamide but not by intravenous pretreatment with the histamine H₁ receptor antagonist chlorpheniramine. Histamine H₂ receptor blockers cimetidine and ranitidine were also without effect. RMeHA did not depress pupillary responses elicited by i.v. (-)-adrenaline.The results demonstrate that histamine H₃ receptors modulate sympathetic activation of the iris at a site proximal to the iris dilator muscle. The predominant mechanism of action appears to the prejunctional inhibition of noradrenaline release from postganglionic sympathetic nerve endings. However, a concomitant ganglionic inhibitory action cannot be excluded. Correspondence to M. C. Koss at the above address     

Antigenemia,immunoblotting, and enzyme immunoassay for early diagnosis of cytomegalovirus infection in renal transplant patients

Timely and rapid diagnosis of cytomegalovirus (CMV) infection is important for the management of transplant patients. We compared three serological assays, IgM immunoblot and IgG/IgM enzyme immunoassay (EIA), as well as the detection of CMV antigens in polymorphonuclear blood leukocytes (antigenemia), for their value in the early diagnosis of CMV infection. Thirty-one patients were monitored longitudinally for 3 months after renal transplantation. Laboratory documented CMV infection occurred in 20 patients. All of these cases showed a positive IgM immunoblot result that was confirmed by at least one of the other test assays (IgG EIA 19/20, antigenemia assay 13/20, and IgM EIA 12/20). All of the ten patients whose clinical picture was compatible with symptomatic CMV disease were positive for CMV infection according to IgM immunoblot and IgG EIA, nine were positive according to the antigenemia assay, and seven were positive according to IgM EIA. With reference to the temporal pattern, the antigenemia assay indicated CMV infection significantly earlier than the serological tests (P0.05). In symptomatic patients CMV antigen-positive leukocytes were, on the average, detected on the day of onset of symptoms, whereas detection by IgM immunoblot, IgG EIA, and IgM EIA followed 8, 13, and 14 days later, respectively. These results show that: (1) the CMV antigenemia assay is very useful for the early diagnosis of symptomatic CMV infections; (2) CMV antibodies, as an indicator of CMV infection, are detectable earlier and more frequently by IgM immunoblot than by IgG/IgM EIA; (3) compared to CMV anti-genemia, the IgM immunoblot indicated CMV infection more often but significantly later; and (4) only a combination of several diagnostic methods allows optimal detection of CMV infections in renal transplant patients.     

Coronary endothelium-protective effects of defibrotide in ischaemia and reperfusion

Summary Defibrotide is known to enhance prostacyclin (PGI₂) release from the vascular endothelium. We investigated the vasoactive effects of defibrotide in isolated rat hearts perfused at constant flow subjected to ischaemia and reperfusion. Defibrotide at 10^–7 or 100 g/ml did not exert any direct vasoactive effect on normal rats hearts. However, ischaemia and reperfusion resulted in an impaired vasodilation to acetylcholine, an endothelium-dependent vasodilator. In contrast, the vasodilator response to the endothelium-independent dilator, nitroglycerin, was unaffected. Defibrotide, at 10^–7 or 100 g/ml, markedly restored the vasodilation to acetylcholine 10^–7 nmol/l to 1 mol/l (P < 0.01) without influencing the vasodilator response to nitroglycerin (2 to 200 g/1). Haemoglobin (150 nmol/l) inhibited the dilation to acetylcholine in response to defibrotide. However, no evidence of (PGI₂) release was observed with acetylcholine-induced vasodilation in the presence or absence of defibrotide. Additionally, 10–100 g/ml of defibrotide did not significantly decrease superoxide radicals generated by a xanthine-xanthine oxidase synthetic system under conditions in which superoxide dismutase was effective. Thus, defibrotide appears to exert an endothelium-protective effect preserving endothelium-derived relaxing factor (EDRF) without directly scavenging free signals.Supported in part by Research Grant No. HL-25575 from the National Heart, Lung and Blood Institute of the NIH Send offprint requests to A. M. Lefer at the above address     

The mycotoxin ochratoxin A is a substrate for phenylalanine hydroxylase in isolated rat hepatocytes and in vivo

Ochratoxin A (OTA), is a mycotoxin contaminating food and feed stuffs, consisting of a chlorinated dihydroisocoumarin linked through a 7-carboxyl group tol-phenylalanine by an amide bond. When OTA (0.12–1.4 mM) is incubated with freshly isolated rat hepatocytes, it inhibits both the hydroxylation of phenylalanine (0.05 mM) to tyrosine, catalyzed by phenylalanine hydroxylase and the subsequent metabolism of tyrosine as measured by homogentisate oxidation. The IC₅₀ of OTA for phenylalanine hydroxylation is 0.43 mM. OT, (0.5–1.0 mM), the dihydroisocoumarin moiety of OTA, does not inhibit phenylalanine hydroxylase activity under these conditions. During incubations of hepatocytes with uniformly labelled [³H]-OTA and unlabelled phenylalanine, tyrosine-ochratoxin A is formed (up to 6% of the total mycotoxin added), indicating that ochratoxin can act as a substrate for phenylalanine hydroxylase. In vivo tyrosine-OTA is also found in liver of poisoned animals.     

绝经后阴道出血242例临床及病理分析

目的 探讨绝经后阴道出血的病因。方法 分析２４２例绝经后阴道出血并行诊断性乔宫的临床和病理资料。结果 绝经后阴道出血的主要病理诊断分另是功能性子宫内膜（６０．７３％）、炎症（２８．９２％）和恶性肿瘤（１０．３５％）。结论 内分泌紊乱性疾病是绝经后出血的常见病因,年老妇女恶性肿瘤发生率高。     

Formulation of a single-component kit for the preparation of technetium-99m labelled ethyl cysteinate dimer: biological and clinical evaluation

Ethyl cysteinate dimer (ECD) labelled with reduced technetium-99m has recently been proposed as a promising radiopharmaceutical for brain perfusion imaging. In the present study a single-component kit formulation has been developed, thus simplifying the radiolabelling procedure. A method of analysis by electrophoresis has also been developed, permitting identification of radiochemical impurities in the preparation. ^99mTc-ECD prepared by the single-component kit was further evaluated in primates and humans. The results demonstrated that the complex is stable in vivo, rapidly extracted and retained in the brain tissue for a sufficient time for single-photon emission tomography studies. Therefore the present single-component kit formulation can be proposed as a reliable instant freeze-dried kit for routine preparation of 99-Tc-ECD required for scintigraphic assessment of regional cerebral blood flow.