Experimental researches in infections with associated myxoviruses in the mouse.

Infections with influenza virus, A/Beijing 353/89 (H3N2) strain, to which there were associated parainfluenza virus type 3, 739-2D strain, adenovirus type 3, and respiratory syncytial virus Long strain, were experimentally induced in white mice. The experimental models were set up so as to permit the obtaining of an associated infection with three viruses, in which the influenza virus should be inoculated the first, the participation of the others being variable, according to their presence by alternation. The infections were detected by means of the presence of homologous serum antibodies, of positive immunofluorescence reactions in the pulmonary tissue, of the histological, histochemical and histoenzymatic lesions at the level of the respiratory system, as well as of pathomorphological changes in other organs. The severity of lesions varied from one to another infection produced by a viral association. At the level of the pulmonary parenchyma, the inflammatory lesion had a frequency of 100%. The severest pathomorphological picture characterized the diffuse interstitial lymphohistio-macrophagocytic bronchopneumonia. The bronchopulmonary block was marked by cytoinfiltrative processes, with a prevalence of lymphocytes in the infection with influenza virus + adenovirus + respiratory syncytial virus, but with a proportionality between lymphocytes and histiocytes in the other infections. The lesion of the highest incidence was the thickening of interalveolar septa, as a consequence of stasis hyperemia, oedema and lymphohistio-macrophagocytic cytoinfiltrate, sometimes associated with hyalinosis of tunica media of the blood vessels and of the Reisseisen's muscle. In other organs, particularly in the liver and kidney, vascular lesions, stasis hyperemia, inflammatory and dystrophico-inflammatory lesions were present; in the spleen, megakaryocyte hyperplasia was recorded at a significant rate in associated infections in which the adenovirus was present.

Experimental infections with some pneumotropic viruses in the mouse. Note II. Virological and pathomorphological aspects of experimental associated infections with parainfluenza virus, adenovirus and respiratory syncytial virus in the mouse.

Associated infections with long-strain parainfluenza virus type 3, adenovirus type 3 and respiratory syncytial virus were experimentally induced in white mice. They were pointed out by the appearance of homologous serum antibodies, positive IF reactions in the pulmonary tissue, and histological, histochemical and histoenzymatic lesions, which were more severe than those of controls infected with single virus of those mentioned above, since they involved wider areas and had a high frequency. The pathomorphological changes made up an inflammatory, exudative, alternative and predominantly infiltrative lymphohistiocytic picture, mainly pulmonary (diffuse interstitial bronchopneumonia, sometimes with a peribronchovascular location, of a cuff-like aspect), hepatic, renal and cardiac, but dystrophic processes were also present--hyalinosis of tunica media in the lung, hepatocyte cytoplasm vacuolizations on areas of various sizes of lobuli--, especially in associated infections with parainfluenza virus type 3 and adenovirus type 3. Megakaryocytic hyperplasia in the spleen, present in all the experimental models, was also described. Generally, the modified structural aspects made up and pointed out a complex pathological process.

Experimental infection of soybean and transmission of Sendai virus through the seeds.

Sendai virus can multiply in the soybean and it can be serially transmitted over at least three passages. The presence of the virus was made evident in leaf homogenates from infected plants after several blind passages in egg chorioallantoic membrane fragments. The virus can be transmitted through the seeds of experimentally infected soybean plants and reisolated from leaves and roots.

Investigations concerning the cultivation of myxo- and paramyxoviruses on chorioallantoic membrane fragments. Note I. Data on the multiplication of several myxo- and paramyxoviruses.

Influenza viruses A(H1N1) and A(H3N2) and parainfluenza viruses (Sendai mumps) were cultivated in chorioallantoic membrane (CAM) fragments maintained in media with different formulae, with or without daily medium changes, in roller or stationary tubes. Inoculation was performed either directly on CAM fragments in Petri dishes or by dilution of the virus-containing material in the medium. Infectant titers obtained in CAM fragments were similar to those recorded in embryonated eggs at 48 hours post inoculation (p.i.) in the case of influenza virus A(H1N1) and at 72 hours p.i. in that of Sendai and influenza A(H3N2) viruses; at 96 hours p.i. all the three viruses had titers superior to those found in the egg.

[Circulation of parainfluenza viruses and adenoviruses in groups exposed to the action of noxious chemicals or not]. / Recherches sur la circulation des virus paragrippaux et des adénovirus dans des collectivités soumises ou non à l'action de substances chimiques nocives.

Investigations were conducted during 1985 and 1986 years on the effect of some chemicals on the parainfluenza and adenovirus circulation in an industrial enterprise community. The presence of type 1, 2 and 3 parainfluenza virus and of adenovirus was revealed by immunofluorescence in exfoliated cells collected from nasopharynx. The kinetic of specific hemagglutination inhibiting and complement fixing antibodies was followed monthly by immunological tests. Meaning of the results is discussed from an epidemiological point of view.

Experimental infections with some pneumotropic viruses in the mouse. Note I. Virological and pathomorphological aspects of the associated infections with influenza virus, adenovirus and respiratory syncytial virus.

In white mice, the associated infections with the influenza virus type A(H3N2), the adenovirus type 3 and the long strain of the respiratory syncytial virus, detected by the appearance of homologous serum antibodies and by positive I.F. reactions in pulmonary tissue, induce histological, histochemical and histo-enzymatic lesions, the severity of which exceeds that of the lesions in animals infected with only one of the mentioned viruses. In comparison with the morphological picture in animals inoculated with a single virus, expressed by inflammatory, infiltrative, lymphohistiocytic pulmonary (infiltrative, interstitial, diffuse, sometimes "cuffing", peribronchial and perivascular broncho-pneumonias), hepatic and renal processes, in the case of associate infections pathomorphological changes appear on wider surfaces and with a high frequency, manifested also by hyalinosis of the vascular media in the lung and the spleen, vacuolization of the cytoplasm of hepatocytes, hypertrophy of the lymphoid follicles in the spleen and the lymph nodes (in associated infection due to the influenza virus+adenovirus and vice versa) or, on the contrary, hypotrophy of the lymphoid follicles in the spleen and lymph nodes (in the associated infection due to the influenza virus+respiratory syncytial virus and vice versa).

Experimental study of the possible implications of some apoptosis mechanisms in the pathogenesis of HIV infection. 1. In vitro apoptotic death of peripheral blood lymphocytes.

The human immunodeficiency virus (HIV) infection produces a gradual depletion of T-helper CD4+ lymphocytes as, surprisingly, a consequence of apoptosis of the uninfected lymphocytes. We suggested that this is the result of the action exerted by HIV inductors of apoptosis (for example, gp 120) in the absence of viral apoptosis suppressor, which confers protection to the infected cell. We intended to demonstrate this hypothesis within the framework of a complex study regarding the apoptosis mechanisms in HIV infection. We started this study by setting up an apoptosis model on HIV-negative peripheral blood lymphocytes (PBLs)* cultivated in vitro in the presence of dexamethasone (Dex). In this work we characterize this model morphologically and biochemically. Three unreported morphological changes observed by us--namely: I) fringing of nucleus with advancement of fringes up to the plasma membrane; II) segmentation and peripheral migration of condensed chromatin through a rotation movement; III) "flowering of the cell" consisting in the radial separation of the lymphocyte into centrally united "petals" with the tendency to form apically multiple apoptotic bodies--completed the classical morphology of the apoptosis phenomenon. The apoptotic death was confirmed by the oligonucleosomal (multiples of 200 bp) and mononucleosomal fragmentation of DNA isolated from lymphocytes.

The effect of ceruloplasmin on the multiplication and on some biological and physico-chemical characteristics of influenza virus A/PR8/34 (H0N1) cultivated on chorioallantoic membrane fragments. Note 1. Kinetics of virus multiplication and of some biological characteristics in the presence and absence of ceruloplasmin.

The presence of ceruloplasmin in the inoculum inhibits the multiplication of influenza virus A/PR8/34 (H0N1) in chorioallantoic membrane fragments. Virus corpuscles that remain uncoupled to ceruloplasmin infect the host cells and their replication results in progens whose properties differ from those of controls inoculated in the absence of ceruloplasmin. The variation in time of the characteristics of the respective virus progens is discussed.

The effect of ceruloplasmin on the multiplication and on some biological and physico-chemical characteristics of influenza virus A/PR8/34 (H0N1) cultivated in chorioallantoic membrane fragments. Note 2. Modifications occurring in the course of serial passages.

The results obtained at the first passage of ceruloplasmin-incubated influenza virus A/PR8/34 (H0N1) in chorioallantoic membrane fragments demonstrate the "trap effect" of ceruloplasmin and are characterized by the low values of the ratios between the hemagglutinating and neuraminidase activities and the infectivity of the resulted progens. At the 2nd passage, both in the absence and in the presence of ceruloplasmin the previously observed changes are accompanied by severe modifications in the antigenicity of the progens, as shown by the HAI titres obtained against a rabbit antiserum to influenza virus A/PR8/34 (H0N1).

Immunogenicity of inactivated vaccines prepared with parainfluenza viruses type 1 and type 3, administered experimentally by nasal or oral route.

The inactivated vaccines prepared with parainfluenza viruses type 1 and type 3, administered to mice by nasal or oral route, either as monovalent preparations in succession or as bivalent associated preparations according to the experimental models used, imparted a significant protection against the infection with the homologous active viruses. The routes of administration of vaccines, nasal and oral, which make equal demands upon the immune secretory serum and cell system, as well as the alternative of inactivated preparations for active virus vaccines are discussed.

The course of some viral respiratory infections in the south-east area of Romania during the cold season 1993-1994. Epidemiological serological and viral data.

Since 1991 we studied yearly the course of some respiratory infections in nine districts of the south-east area of Romania, by collecting epidemiological and sero-viral data during the cold seasons (1) (2). The results pointed out the most frequent circulating viruses, as well as the influenza strains which caused epidemic outbreaks. The same line of investigation was followed during the cold season November 1993-- March 1994 in the mentioned geographic area. In the present study are shown the results obtained in this period.

[The circulation of influenza virus in human communities subjected to the action of noxious chemical substances]. / Recherches sur la circulation des virus de la grippe dans des collectivités humaines soumises à l'action de substances chimiques nocives.

Investigations were conducted during 1985 and 1986 years on the effect of some noxious chemicals on the influenza virus circulation in an industrial enterprise community. The presence of influenza virus type A (H1N1), A (H3N2) and B was revealed by immunofluorescence in exfoliated cells collected from nasopharynx. The kinetic of type specific hemagglutination inhibiting antibodies was followed monthly. Chick embryos were used to isolate influenza virus strains. Meaning of the results is discussed from an epidemiological point of view.

Studies concerning the course of some acute respiratory diseases in nine districts of south-east area of Romania between November 1994 and April 1995. Epidemiological, virological and serological data.

A moderate level of morbidity through acute respiratory diseases (ARD), of the upper tract, viral pneumonia and clinical influenza was recorded during November 1994 and April 1995 in the South-East area of Romania (nine districts). By virological and serological investigation adenosyncytial respiratory, parainfluenza type 3 and influenza type B viruses were found to be the most frequent etiological agents of these infections which affected especially the babies and the children of 1-14 years of age. Sporadic influenza outbreaks were noticed from which influenza strains of virus were isolated, antigenically related to the prototype strain A/Johannesburg 33/94.

Experimental study of possible involvement of some apoptosis mechanisms in pathogenesis of the HIV infection: 2. The CD4+ T lymphocytes depletion in the HIV infection occurs through activation-induced apoptosis.

The present work is a part of a complex experimental study aimed at the demonstration of the two previously published hypotheses regarding the involvement of apoptosis in general in the viral infection and especially in HIV infection (1). Our researches have shown that the significant lowering of the number of peripheral CD4+ T lymphocytes in HIV-infected children is associated with a marked increase of the soluble interleukin 2-receptor (sIL2-R)# concentration, in comparison with HIV-negative, healthy or acute infections exhibiting controls. As sIL-2R is a circulating marker of cell activation, we investigated the role of monocytes (antigen-presenting cells) in the viability of peripheral lymphocytes isolated from HIV-infected children in comparison with the controls. Lymphocytes cultivation in the absence and in the presence of autologous monocytes led to the following conclusions: 1) freshly isolated lymphocytes from HIV-positive individuals undergo an accelerated spontaneous apoptosis in comparison with that of lymphocytes isolated from HIV-negative individuals: 2) the normal antiapoptotic effect of monocytes on lymphocytes diminishes gradually in the HIV infection, changing into a proapoptotic effect, corresponding to the sIL-2R augmentation to increasingly higher values. Our results show that peripheral CD4+ T-lymphocyte depletion in HIV infection occurs through apoptosis and the activation-induced cell death is one of the possible apoptosis mechanisms.

Some characteristics of Sendai virus envelope solubilization by different detergents.

Gel-filtration through Sepharose-2B of Sendai virus envelopes solubilized by Tween-20 or Triton X-100 treatment allows the separation of two elution peaks, hemagglutinin (HA) activity being detected only in the peak corresponding to large envelope fragments. Solubilization of the same virus envelopes with N-octylglycoside (NOG) results in a single elution peak, exhibiting both HA and neuraminidase activities. The results obtained suggest : 1) the similar envelope composition of the different virus populations, and 2) the different mechanisms of solubilization, in relation to the detergent used for disruption. The advantages of virus disruption by NOG are discussed.

The effect of ceruloplasmin on experimental infection with influenza virus APR 8/34 (H0N1) in the mouse.

Ceruloplasmin administered in different variants confers on mice protection against experimental infection with influenza virus APR 8/34 (H0N1). The optimal variants are: inoculation of an extemporaneous virus-ceruloplasmin mixture, followed by two additional ceruloplasmin applications (which confers maximum protection against initial infection) and the administration of ceruloplasmin prior to virus inoculation (which assures the highest resistance to challenge infection).

Comparative results of respiratory virus isolation attempts in chorioallantoic membrane fragments and embryonated chicken eggs.

Attempts performed with 39 samples of nasopharyngeal secretion resulted in the isolation of 21 (54%) hemagglutinating viral agents in chorioallantoic membrane (CAM) fragments, while a single strain (2.5%) was isolated in the embryonated egg. The time interval required for virus isolation in CAM fragments ranged from 4 to 20-24 days and was longer then 10 days in the embryonated egg. Maintenance of CAM fragments in roller tubes leads to a more abundant virus multiplication and, implicitly, to a reduction of the time interval necessary for virus isolation.

Electron optic investigations on influenza virus A(H1N1) interacted with some aromatic compounds.

The morphological changes caused by the interaction of influenza virus A(H1N1) with three fluorescent aromatic compounds (a vinyl-sulfonic and an isocyano naphthalic acid derivative and the 4-acetylamino-naphthalene-1,8-dicarboxylic acid) were studied in the electron microscope. The intensity and type of the alterations depend on the chemical structure of the compounds and can be correlated with their effect on the biological activities of influenza virus.

Epidemiological, viral and serological studies concerning the evolution of some acute respiratory diseases between November 1992 and March 1993 in nine districts of the south-east area of Romania.

Viral and serological studies led to the conclusion that parainfluenza type 3 and influenza type A(H3N2) viruses were the most implicated in the etiology of acute respiratory diseases (ARD), viral pneumonia and clinical influenza in nine districts of the south-east area of Romania during the November 1992--March 1993 period. Epidemiological survey pointed on the 0-1 year group of age as the most affected by the above mentioned respiratory diseases.

Epidemiological, viral and serological studies concerning the evolution of some acute respiratory diseases between November 1992 and March 1993 in nine districts of the south-east area of Romania.

Viral and serological studies led to the conclusion that parainfluenza type 3 and influenza type A(H3N2) viruses were the most implicated in the etiology of acute respiratory diseases (ARD), viral pneumonia and clinical influenza in nine districts of the south-east area of Romania during the November 1992-March 1993 period. Epidemiological survey pointed on the 0-1 year group of age as the most affected by the above mentioned respiratory diseases.