Electron microscopy study of the pox-like virus of Melolontha melolontha L (Coleoptera,Scarabeidae)

Summary The morphogenesis ofMelolontha pox-like virus was studied by electron microscopy on ultrathin sections of infected adipose cells. The development of the virus occured in virogenic areas, in the vicinity of the nucleus, where different types of immature virus particles could be identified: crescent-shaped particles, spherical particles with a low electron opacity or filled with a dense material. All these virus particles were limited by two membranes, the inner one showing a unit membrane structure. Ovalshaped mature particles dispersed in the cytoplasm showed a complex structure. They possess a concave core made of a dense material with a thready structure delimited by a three-layered membrane. An external coat of irregular thickness covers them. An electron dense substance occupies the space between the viral envelopes and the core, in the concavity of which it forms a lateral body. The occlusion of mature particles in paracrystalline inclusions is characteristic of this affection. Most of the developmental stages observed resembled those previously described in the pox group. This resemblance is discussed and an hypothetical scheme of the maturation of the virus is proposed.

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Résumé La morphogénèse du virus du type pox deMelolontha a été étudiée en microscopie électronique sur des coupes ultrafines de cellules adipeuses infectées. Le virus se développe dans les régions virogènes, à proximité du noyau, où différents types de particules de virions immatures ont pu être identifiés: particules en forme de croissant, particules sphériques à faible opacité électronique ou contenant une matière dense. Toutes ces particules sont limitées par deux membranes, la membrane intérieure montrant une structure à membrane unitaire. Les particules mûres de forme ovale dispersées dans le cytoplasme ont une structure complexe. Elles possèdent un centre concave dense à structure fibreuse délimité par une membrane à trois couches. Une enveloppe externe d'épaisseur irrégulière le recouvre. Une substance dense aux électrons occupe l'espace compris entre les enveloppes virales et le centre et forme un corps latéral. L'occlusion des particules mûres dans les corps d'inclusions paracristallins est caractéristique de cette affection. La plupart des stades de développement observés ressemblent à ceux des virus du groupe pox précédemment décrits. Cette ressemblance est discutée et un schema de maturation du virion est proposé.

     

Rantes distribution and cellular localization in the brain of HIV-infected patients

OBJECTIVE: To study the immunochemical distribution ofRantes chemokine and its correlation with HIV-p24 expression, in brains with HIV-related lesions. MATERIAL AND METHODS: 17 HIV-positive cases of HIV-related brain lesions, 7 HIV-positive cases without cerebral HIV-related lesions (5 with opportunistic brain diseases), and 7 HIV-negative cases as controls (4 with brain lesion) were selected. RESULTS: High expression of Rantes was observed in the cases with inflammatory brain lesions (22/24 HIV-positive and 2/7 HIV-negative patients). Positivity was observed in the diffuse and nodular microglial cells and lymphocytes. In the patients with HIV-related lesions, the presence of Rantes-stained microglia did not correlate with that of HIV-p24-positive cells. Positive astrocytes were only found in the HIV-positive patients. Multinucleated giant cells were always Rantes-negative. CONCLUSIONS: Our results seem to demonstrate the role of Rantes chemokine in inducing inflammatory brain perivascular and microglial reactions both in HIV-positive and -negative patients.     

Experts’ considerations on HLA‐haploidentical stem cell transplantation

Recently, novel strategies to control graft‐versus‐host disease and facilitate engraftment have allowed an increasing number of human leukocyte antigen (HLA)‐haploidentical hematopoietic stem cell transplantation (haploHSCT) to be performed. A meeting was convened to review the biological rationale and the clinical results of various T‐cell‐depleted (TCD) and T‐cell‐replete (TCR) HLA‐haploidentical ‘transplant platforms’. The objective of the meeting was to promote discussion and consent among leading researchers in the field on three main crucial issues for haploHSCT: (i) eligibility criteria, (ii) choice of the most suitable donor, and (iii) choice of the most appropriate transplant platform. The experts in attendance agreed that a patient who is eligible for an allogeneic transplant and lacks an HLA‐identical sibling or an HLA‐matched unrelated donor should be considered for an alternative donor transplant. Together with the experience of the individual center, the most important decision criteria in choosing an alternative donor source should be the rapidity of transplantation so as to avoid disease relapse/progression. The choice of the mismatched donor should be driven by younger age, ABO blood group compatibility, and Cytomegalovirus status. If a TCD transplant is planned, NK‐alloreactive donors and/or the mother should be preferred. Prospective comparative studies are needed to establish the relative efficacy of different transplant platforms. However, expertise in stem cell manipulation and in adoptive immunotherapy is essential if a TCD transplant platform is chosen.     

Beta amyloid precursor protein and patterns of HIV p24 immunohistochemistry in different brain areas of AIDS patients

OBJECTIVES: To evaluate the correlation between immunohistochemical positive patterns (globular and filamentous structures) of beta-amyloid precursor protein (beta-APP), used as a marker of axonal damage, and the different distribution of HIV p24 antigens, in three different brain areas of AIDS patients. METHODS: Eighteen AIDS patients with HIV-related brain lesions were included in the study. Forty-nine sections from basal ganglia, frontal cortex and hippocampus were selected. After microwave oven pre-treatment, the sections were incubated with anti-HIV p24 and anti-beta-APP monoclonal antibodies; the reactions were developed with peroxidase/3,3'diaminobenzidine. The positivity was graded by semi-quantitative scores. Double immunohistochemical staining was used to evaluate the co-localization of the antigens. RESULTS: HIV p24 immunohistochemistry was positive in 44 of 49 sections (89%), with a prevalence of interstitial positive cells and positive microglial nodules in 27 and 13 sections respectively. beta-APP-positive structures were demonstrated in 23 of 44 sections (52%) with HIV-related lesions, and were absent from the five sections without viral expression. Globular and filamentous lesions were observed in 21 of 23 sections and 10 of 23 lesions respectively. Moreover, a high grade of globular type lesion was related to an elevated presence of diffuse interstitial HIV p24-positive cells in basal ganglia; double immunohistochemical reactions demonstrated the co-localization of beta-APP globules and HIV p24 antigens. CONCLUSIONS: The data obtained confirm the coexpression of beta-APP and viral antigens in particular areas of the brain with HIV-related lesions; there is a strict correlation between beta-APP globules (indicating chronic cerebral damage) and the interstitial pattern of HIV p24 immunohistochemistry.     

Alpha 1 adrenoceptor subtype mediates noradrenaline induced contraction of the human internal mammary artery: radioligand and functional studies.

STUDY OBJECTIVE--The aim was to evaluate the characteristics of alpha adrenergic binding sites on human internal mammary arteries and the alpha adrenoceptor mediated vasoconstrictor response to catecholamines. DESIGN--Human internal mammary arteries were cut longitudinally, the intimal layer was scraped, and the arteries homogenised and centrifuged at 50,000 g to obtain a membrane pellet. Saturation isotherms with [3H]-prazosin were done with 50-100 micrograms plasma membranes per tube and increasing concentrations of [3H]-prazosin (non-specific binding: 2.5 mM noradrenaline plus superoxide dismutase and catalase). Kinetic isotherms were done with 100 micrograms plasma membranes and 1-5 nM [3H]-prazosin for time periods ranging from 1 to 90 min; at the equilibrium, dissociation of [3H]-prazosin was achieved by 10 microM prazosin. alpha 2 Adrenoceptor density on internal mammary artery membranes was assessed with [3H]-rauwolscine (non-specific binding: 1 microM yohimbine). Separation of membrane bound radioactivity was achieved by rapid vacuum filtration through Whatman GF/C fibre filters. Saturation isotherms were evaluated by Scatchard plots and kinetic data, and competition isotherms by Enzfitter analysis. Contractility studies were done with helical strips of artery (without adventitial layer) placed in a thermostated perfusion bath. Data were obtained in the presence of different concentrations of agonists and antagonist to obtain Schild plots. Antagonist drugs were employed at only one concentration for each preparation. SUBJECTS--Mammary arteries were collected from 51 patients (age range 42-65 years) undergoing surgery for coronary grafting. MEASUREMENTS AND MAIN RESULTS--The binding of [3H]-prazosin to arterial plasma membrane was rapid and reversible. The K + 1 was 0.13 (SD 0.03) X 10(9) M.min-1 (n = 5) and the Kd, determined as a ratio between k-1/K + 1, was 0.34(0.01) nM (n = 5). [3H]-Prazosin binding, displaceable by 2.5 mM (-)-noradrenaline, was saturable and disclosed an alpha 1 adrenoceptor density of 30(3) fmol.mg-1 protein with a dissociation constant (Kd) of 215(50) pM (n = 18). The adrenergic agonists competed with [3H]-prazosin in the following order of potency: (-)-adrenaline [Ki = 0.6(0.1) microM; n = 5] greater than (-)-noradrenaline [Ki = 1.05(0.015) microM; n = 12] much greater than (-)-isoprenaline [Ki = 150(10) microM; n = 4]. Specific binding of [3H]-rauwolscine to IMA plasma membranes was negligible (about 2 fmol.mg-1 protein) (n = 15) with an unfavourable ratio of non-specific v specific binding. Catecholamines induced a dose dependent contractile response in arterial strips; (-)-noradrenaline: EC50 = 0.48(0.12) microM, n = 20; (-)-adrenaline: EC50 = 0.15(0.16) microM, n = 10; and methoxamine, a selective alpha 1 adrenergic agonist: EC50 0.67(0.15) microM, n = 10. The alpha 2 adrenoceptor agonists BHT-933, BHT-920, and guanabenz did not contract the arterial strips (up to 10 mM). Prazosin (0.03-0.1 microM) produced concentration dependent right shifts of the (-)-noradrenaline [pA2 = 9.83(0.11), n = 19], (-)-adrenaline [pA2 = 9.50(0.31), n = 10], and methoxamine [pA2 = 8.96(0.18), n = 10] concentration-response curve. CONCLUSIONS - Internal mammary artery plasma membranes possess alpha 1 adrenoceptors which are involved in the vasoconstrictor response to catecholamines. alpha 2 Adrenoceptors seem not to be involved.     

Functions of the plasminogen receptor Plg‐RKT

Plg‐R_KT is a structurally unique transmembrane plasminogen receptor with both N‐ and C‐terminal domains exposed on the extracellular face of the cell. Its C‐terminal lysine functions to tether plasminogen to cell surfaces. Overexpression of Plg‐R_KT increases cell surface plasminogen binding capacity while genetic deletion of Plg‐R_KT decreases plasminogen binding. Plasminogen binding to Plg‐R_KT results in promotion of plasminogen activation to the broad spectrum serine protease plasmin. This function is promoted by the physical association of Plg‐R_KT with the urokinase receptor (uPAR). Plg‐R_KT is broadly expressed in cells and tissues throughout the organism and its sequence is remarkably conserved phylogenetically. Plg‐R_KT also is required for lactation and, thus, is necessary for survival of the species. This review provides an overview of established and emerging functions of Plg‐R_KT and highlights major roles for Plg‐R_KT in both the initiation and resolution of inflammation. While the roles for Plg‐R_KT in the inflammatory response are predominantly plasmin(ogen)‐dependent, its role in lactation requires both plasminogen‐dependent and plasminogen‐independent mechanisms. Furthermore, the functions of Plg‐R_KT are dependent on sex. In view of the broad tissue distribution of Plg‐R_KT, its role in a broad array of physiological and pathological processes should provide a fruitful area for future investigation.     

Prognostic significance of cardiac magnetic resonance-based markers in patients with hypertrophic cardiomyopathy

The International Journal of Cardiovascular Imaging - The prognosis of patients with hypertrophic cardiomyopathy (HCM) varies greatly. Cardiac magnetic resonance (CMR) is the gold standard method...     

High frequency of Epstein-Barr virus genome detection in Hodgkin's disease of HIV-positive patients

Lymph nodes obtained from 7 HIV-positive and 20 HIV-negative patients with Hodgkin's disease were examined for the presence of Epstein-Barr virus antigens and genome. EBV antigens were observed in only 2 out of 20 HIV-negative patients, whereas lymph nodes of HIV-positive patients did not reveal evidence of EBV antigens. By in situ hybridization and Southern blot analysis, EBV genome was found in 5 out of 7 HIV-positive patients; the EBV genome was detected in the nucleus of Reed-Sternberg and Hodgkin's cells. EBV DNA was observed by in situ hybridization and Southern blot analysis in only 3 out of 20 HIV-negative patients with Hodgkin's disease. In both groups, Reed-Sternberg and Hodgkin's cells were negative for C3d EBV receptor. Our results show a statistically significant increased expression of EBV DNA in HIV-positive patients with Hodgkin's disease, as compared with HIV-negative patients with HD.