A micropopulational modelling of a viral epidemic by using a special neural network.

A general forward neural network was adapted for a simulation of viral epidemics. This involves the introduction of a strongly dependence upon history, upon the cumulated values of the corresponding neuron (individual) activations (states of infection) specifying the activation (health) states of the contaminated individuals, represented by the activated neurons and the dynamic parameters of the neural network: the matrix of the synaptic connection and the vector of the activation thresholds (corresponding to the matrix of the viral transfers between the various individuals and to the vector of the minimal individual contamination doses of virus). The recurrence relations and the learning procedures were also adapted to these processes. This methodology was used for the study of the micropopulational spreading of viral epidemics in various epidemiological situations.

Spectral and biological characteristics of some Acyclovir salts.

In the present work there are described some spectral characteristics in the ultraviolet and infrared region under various environment conditions for a series of synthetic analogues of deoxyguanosine, substances possessing antiviral properties. The study is performed on the Acyclovir compounds and on its Na, K and Li salts, synthetized in Romania, in comparison with the similar product Zovirax, of the "Wellcome" firm (England), used in the clinical practice for several years. The results show a very marked resemblance of the spectral behavior for all these products, a conclusion confirmed by the similar biological effects in the herpetic infection.

Natural propolis extract NIVCRISOL in the treatment of acute and chronic rhinopharyngitis in children.

In the work there are shown the results of a "case control" study carried out in a children collectivity (preschool children and school-children), regarding the action of an aqueous propolis extract, NIVCRISOL, in acute and chronic inflammatory diseases of the upper airways. The preparation, which had a rich content of flavonoids, was administered to a group of preschool children and school-children treated during the whole cold season 1994-1995. The monitoring of the subgroups investigated was performed by clinical observation of the health state and recording of the incidence of symptoms characteristic to acute or chronic rhinopharyngeal diseases, as well as by a periodical laboratory examination for the detection and characterization of viral, microbial and fungal germs carriage. The analysis of the data obtained pointed out the favourable effects of this local treatment, expressed by lowering of the number of cases with acute or chronic symptoms, and decrease and sometimes suppression of the viral-microbial flora carriage of the upper airways. These positive results, the good tolerance of the preparation, the advantages of the therapy with natural products and more economic criteria entitle us to propose the administration of this preparation as an adjuvant medication in the local treatment of some clinical forms of acute or chronic rhinopharyngeal diseases.

Flow cytometric study of the epirubicine accumulation modulation in the human erythrocytes by a Nocardia opaca fraction.

The effect of the "Nocardia lysozyme digest" (NLD) obtained from Nocardia opaca on the Epirubicine accumulation in erythrocytes was studied by flow cytometry. It was shown that the number of fluorescent cells increased under the NLD action due to the increased membrane permeability for epirubicine. An opposite effect was also recorded consisting in the decrease of the relative fluorescence intensity per cell. This effect was attributed to the fluorescence quenching by the oxygen metabolites produced by NDL. In this paper we present some results of the study of the NLD effect on the epirubicine (Epir) accumulation in the erythrocytes (E). It is shown by flow cytometry that the Epir accumulation in the red cells is modified by the presence of the NLD fraction.

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.

Empirical decompositions of overall AIDS epidemics in local epidemics using generalized neural networks.

A generalized neural network was adapted for the simulation of processes strongly dependent upon the history, imposed by the inner own history of an individual neuronal activation. This involves the dependence of the neural network parameters upon the cumulated values of the corresponding neuron activations. When in the neural network weakly coupled blocks with strong inner couplings can be identified, the activation wave on the entire network (associated with the overall epidemic) can be decomposed into quasi-independent intra-block local activation waves, with characteristic delays between them (corresponding to the simultaneous and successive local epidemics). Special simulations on strongly connex neural network determine the typical local activation waves for various block parameters and the mentioned delays between two such successive activation waves in two coupled blocks. Another type of neural network is used to achieve the empirical decomposition of the overall epidemic into simultaneous (corresponding to a layer) and successive local epidemics (corresponding to the various epidemic waves, associated with different layers). A simpler approximative algorithm for the estimation of the number of the mentioned simultaneous local typical epidemics is also presented.

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.

Simulation of a viral epidemic by means of a neural network.

The neurons of the network used for the simulation of a viral epidemic correspond to the individuals of the community. The activation state of the neurons reflects the contagious state of the diseased persons. Variable thresholds are introduced for the differentiation of the neuronal non-activation states (susceptible or immune subjects). The thresholds are calculated depending on the cumulated values over time of the neural activation states. The network functions synchronously. In order to follow up the state of the neural network, recurrence relations were introduced. They were applied in two epidemiological situations which differ from each other by the spreading intensity of the virus over time, reflected by the particular values ascribed to the elements of the neural connection matrix.

Investigations on the influence of the experimental infection with the herpes simplex virus type 1 on the electrophoretic mobility of some cultured cells.

Two types of cell cultures, BSC and HE-p2, have been studied from the microelectrophoretic point of view. Determinations have been made for infected cells (collected at 48 or 72 hours after infection) and for control cells, immediately after their separation from the culture, or after preserving them for 24 hours or more in migration buffer. The electrophoretical mobility increases with an average of 10% in the case of infected cells, as compared to the controls. This parameter offers a distribution of values varying from the gaussian curve to the bimodal one. From the microelectrophoretic point of view, the HEp-2 cells are more stable and respond more uniformly than BSC cells.

Mathematical stochastic models of some typical viral epidemiological evolutions.

The formalisms of the probability distribution and of the associated generator function are used to establish the equations for the first and second moments of the numbers of susceptible and contagious individuals. Applications are given for the linear cases for the epidemic evolutions, for the endemic situations and for virosis in course of eradication.

Use of Harvard Graphics program in processing of the results obtained from investigations on involvement of some viruses in malignant human diseases.

Different possibilities of graphic representation of the results obtained from investigations on the involvement of some viruses in the malignant and nonmalignant human pathology are analysed. The Harvard Graphics package available in many IBM compatible computers was used. Owing to its several graphic options and access to the drawing area it was preferred to the Epi Info-program specialized in recording and numerical processing of epidemiology data and lesser in their graphic representation.

[The action of amphiphilic drugs on human fibroblasts in vitro. Their possible use in antiviral and antitumor chemotherapy]. / Observations sur l'action de quelques drogues amphiphiles sur les fibroblastes humains in vitro. Applications possibles en chimiothérapie antivirale et antitumorale.

The LDH cytotoxicity test is able to emphasize the stabilisation of human embryo fibroblast membranes, in vitro, by two amphiphilic drugs: the metomidate and the thymolol. The membrane stabilisation is emphasized by the reduced LDH externalization as compared with the untreated cells. The use of the LDH test for the selection of some natural complexes or synthetic drugs with membrane stabilising and potential antiviral activity is proposed. The inhibition of LDH by metomidate was recorded, as decreasing of the enzyme activity with increasing metomidate concentration. This fact explains the known lactic acid accumulation, under metomidate treatment of human subjects. The use of metomidate in classical cancer treatment potentiation is proposed instead of lactate externalization inhibitors, already used for this aim.

The evidence of circulation of some viruses in a great town of Romania during the first half of 1992.

Complex serological survey performed in the town B. during the first half of 1992 emphasized an active circulation of some respiratory viruses, especially of parainfluenza type 3 and 1, influenza subtypes A(H3N2) and A(H1N1), adeno and syncytial respiratory as well as of Mycoplasma pneumoniae. Less important was the frequence of antibodies against Chlamydia psittaci, East equine, West Nile and tick-borne encephalitis as well as parainfluenza type 2 and influenza type B viruses.

A laboratory computer adapted for running also as a chronometer.

The program realizes the integration in the laboratory computered informational flow of the experiments in which determinations of the time intervals are made, such as cellular electrophoresis. This program consists of two components, the chronometer and the laboratory watch, which work independently. For the measurement of the time intervals, with a precision of 0.02 sec., the internal clock of the computer is used. Two independent time lists (S and D) can be controlled at the same time (alternatively). The specialized modules of the timing program realize the measurement and the storage of the time intervals, the processing (transformations and numerical processing) and the storage of the time intervals lists, their display and printing. With the laboratory watch one can set and follow five marks of time intervals, having the same origin. The commands are given from multiple menus and are accompanied by information under the form of helping texts.

[A library of procedures in LOTUS 1-2-3 for the rapid processing of laboratory data]. / Bibliothèque de procédés en LOTUS 1-2-3 pour le traitement rapide des données de laboratoire.

A series of MACROS have been drawn in order to eliminate the steps between the initial data and the final results. There are described more than 20 groups of MACROS for general mathematical operations and statistical works (t and chi-square tests, which are interpreted). Besides mentioning the input data, there are given details on reading the output results. The method described here can be used to easily develop this MACRO library, by adding new MACROS which should respond exactly to the specific data processing operations of each laboratory. Examples with data from the virology laboratory show using of these MACROS by any user, even those having a minimum knowledge about LOTUS 1-2-3 or about data processing.

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.

[Library of LOTUS 1-2-3 macros for the rapid processing of laboratory data]. / Bibliothèque de procédés en LOTUS 1-2-3 pour le traitement rapide des données de laboratoire.

A series of MACROS have been drawn in order to eliminate the steps between the initial data and the final results. There are described more than 20 groups of MACROS for general mathematical operations and statistical works (t and CHI square tests, which are interpreted). Besides mentioning the input data, there are given details on reading the output results. The method described here can be used to easily develop this MACRO library, by adding new MACROS which should respond exactly to the specific data processing operations of each laboratory. Examples with data from the virology laboratory show using of these MACROS by any user, even those having a minimum knowledge about LOTUS 1-2-3 or about data processing.

[Epidemiological and virological research on influenza and viral respiratory infections in the southeastern region of Romania in the cold season of 1991-1992]. / Investigations épidémiologiques et virologiques concernant la grippe et les infections respiratoires virales dans la région du sud-est de la Roumanie au cours de la saison froide 1991-1992.

Investigations pointed out the high level of respiratory diseases and pneumonias in children, especially in the youngest ones (0-1 year-old) during all the surveyed period. An influenza outbreak during the second half of February was registered in the infantile population--school and low-age children--which gave most of the cases. Serology and isolations incriminated an influenza virus related to the A/Beijing 353/89 (H3N2) strain. Isolations worked out after the influenza epidemics pointed out circulation of parainfluenza and adenoviruses. The necessity is emphasized of the anti-influenza vaccination of low-age children.

[Complex studies of virology, microbiology, biochemistry and epidemiology in the adults of a semi-closed community vaccinated against influenza with the inactivated NIVGRIP vaccine intranasally]. / Etudes complexes de virologie, microbiologie, biochimie et épidémiologie sur des adultes d'une collectivité semi-fermée, vaccinés contre la grippe avee le vaccin inactivé NIVGRIP par voie intranasale.

A study was conducted on the specific and non specific immunomodulator effects of the inactivated vaccine NIVGRIP. The results revealed the seroconversion of HAI antibodies against influenza and mumps viruses and the reduction of viral and microbial flora of the pharynx. The kinetics of some proteins specific to the acute stage (siderophiline antitrypsin, microglobulin, complement C1q and C2 factors, C reactive protein and fibronectin) was also investigated and significant quantitative modifications were noticed in vaccinated subjects. The mean illness duration (acute respiratory disease) was three times as short in vaccinated subjects as in controls.