Why is it necessary to examine retina when the patient suffers from aplastic anemia?

PURPOSES: To inform about a case of Revesz syndrome (RS) with initial ophthalmological symptomatology of severe proliferative vitreoretinopathy of the left eye (LE). After the aplastic anemia had developed, RS was established. The exudative retinopathy was successfully treated with photocoagulation on the right eye (RE). BACKGROUND: RS is characterized by fatal bone marrow failure, exudative retinopathy, neuroradiographic abnormalities, neurodevelopmental delay and skin abnormalities. Non-treated exudative retinopathy leads to blindness. METHODS: We report ophthalmological findings as follows: fundus photography and fluorescein angiography (FA) acquired by examinations under general anesthesia in patient with RS. Results of genetic tests helped to establish the diagnosis. RESULTS: Two­year old Caucasian male was examined due to total retinal detachment on LE and signs of chorioretinal scarring on RE. In preoperative screening, thrombocytopenia was detected; later, severe pancytopenia developed. Considering the hematological findings and clinical appearance, we suspected RS, which was confirmed by genetic tests. We found a pathogenic mutation in gene TINF2 (variant c.865C>T;p.Pro289Ser) in a mosaic state with autosomal dominant mode of inheritance. This mutation has not been described in RS yet. Blind LE was enucleated because of dolorous neovascular glaucoma. FA of RE shows excessive areas of capillary nonperfusion with vascular abnormalities and exudation. After the photocoagulation, the visual acuity (VA) on RE remains 0.9 at the age of 7 years. CONCLUSIONS: RS is an extremely rare condition.  The initial symptomatology could be ophthalmological or hematological. The positive finding of TINF2 gene mutation helped in establishing the correct diagnosis. The ischemic retinopathy was successfully treated by photocoagulation (Fig. 6, Ref. 6). Text in PDF www.elis.sk.

Learning from errors: when a low platelet count in neonate excludes immune thrombocytopenic purpura in mother.

This paper reviews the most common causes of thrombocytopenia in the newborn. It mentions few classification schemes that clearly characterize the most common causes, diagnosis and treatment approaches for neonatal thrombocytopenia. Particular attention is paid to inborn macrothrombocytopenia without congenital anomalies. They represent a rare group of diseases, often captured randomly or during routine examinations. An attention is paid on congenital macrothrombocytopenia variants with mutations in the MYH9 gene. If they are not associated with other disorders (deafness, presenile cataracts, nephritis or renal failure), they may be mistakenly diagnosed as the acquired immune thrombocytopenic purpura (ITP). This distinguishing is essential to avoid potentially harmful and unnecessary treatment. The listed case report points to a situation where a detection of the root causes of neonatal thrombocytopenia led to a review of misdiagnosed ITP in the mother. A platelet size evaluation by both an appropriate cell counter and blood film examination is useful for differentiating a heterogeneous group of rare inherited macrothrombocytopenias. A healthy twin supported autosomal dominant inheritance. The results of investigations of twins and mother confirmed the congenital/inherited macrothrombocytopenia from the group of MYH9-related diseases (Tab. 5, Fig. 2, Ref. 21).

In vitro cultivation studies on the Skalica strain of tick-borne encephalitis virus.

The Skalica strain of tick-borne encephalitis virus was cultivated in mouse organ cultures. In the fluids from spleen, liver, brain and spinal cord cultures, maximum infectivity titres of 8.1--8.3 log LD50/0.01 ml were found 6 and 9 days after inoculation. In the fluids from lymph node and muscle cultures, maximum infectivity titres of 4.2 and 6.5 log LD50/0.01 ml, respectively, were detected 6 days after inoculation. Neither interferon nor haemagglutinin nor complement-fixing antigen was demonstrated in media from explant cultures from the 3rd to the 15th day of cultivation. Fifteen days after seeding, haemagglutination inhibiting antibodies were detected in the fluid phase of lymph node, spleen and liver explant cultures derived from mice infected 6 days previously, as were complement-fixing antibodies in the fluid phase of lymph node, spleen, liver, lung, brain and spinal cord explant cultures derived from mice infected 14 days previously.

Characteristics of some tick--borne encephalitis virus strains isolated in Slovakia.

Several tick-borne encephalitis (TBE) virus strains isolated in Slovakia from 1974-1978 were characterized by their cytophatic abilities, sensitivity to heating at 50 degrees C and to 2 M urea, and pathogenicity for white mice. Strains isolated from Ixodes ricinus ticks differed in pathogenic properties from those isolated from Clethrinomys glareolus. The latter strains (Skalica) may be considered a spontaneous variant of TBA virus with decreased virulence for mice.

A simple method of preparing a complement-fixing antigen from the virus of haemorrhagic fever with renal syndrome (Western type).

Different methods of the preparation of haemorrhagic fever with renal syndrome (HFRS) antigen for complement-fixation (CF) test are described. The antigens were prepared from the organs of suckling white rats inoculated with the Western type of HRFS by precipitation with polyethylene glycol, by fluorocarbon treatment and or by sucrose-acetone extraction. The highest CF titre was obtained by acetone precipitation of 20% brain suspension in isotonic sucrose.

Vesicular stomatitis virus pseudotype with neutralization antigen of tick-borne encephalitis virus.

Vesicular stomatitis virus (VSV), when grown in dual infection with tick-borne encephalitis (TBE) virus, produced pseudotype VSV (TBE) with surface proteins provided by TBE virus. This phenomenon can be employed in a rapid, accurate and sensitive test for detection and assay of neutralizing antibodies specific for TBE virus.

Antigenic variation of the viruses belonging to the tick-borne encephalitis complex as revealed by human convalescent serum and monoclonal antibodies.

Solid-phase enzyme-linked immunoassay (ELISA) was used for the detection of antigenic relationships and/or differences among the viruses belonging to the tick-borne encephalitis (TBE) complex. Monoclonal antibodies of IgM class with haemagglutination-inhibiting activity to the Skalica strain of TBE virus were used to compare the TBE complex viruses. Antigenic analysis of 9 viruses of the TBE complex, isolated from Eurasia and America showed close relationships among them. Nevertheless, it was possible to differentiate the Skalica strain from Langat, louping-ill and Omsk haemorrhagic fever (OHF) viruses by ELISA when monoclonal antibodies and antigens were diluted 1:10,000. Monoclonal antibodies to the Russian spring-summer encephalitis virus did not react with the Skalica strain in immunofluorescence test. By the use of convalescent serum no reaction was found with louping-ill, Russian spring-summer encephalitis, Powassan and OHF viruses in haemagglutination-inhibition (HI) test.

To the antigenic classification of some viruses from the tick-borne encephalitis complex by monoclonal antibodies.

Two monoclonal antibodies (MoAb) to the Skalica virus from the tick-borne encephalitis (TBE) complex were used to compare Karshi and Royal Farm viruses with the Russian spring-summer encephalitis, Central European encephalitis (Hypr and Kumlinge strains) Skalica, Langat and Powassan viruses. The first MoAb was prepared by fusion of P3NS1 cells with BALB/c mouse spleen cells, immunized with the Skalica virus; it was of IgM class and reacted in haemagglutination-inhibition (HI) test (MoAb type 1). The second MoAb was of IgG class and reacted in complement-fixation (CF) test (MoAb type 2). MoAb type 1 reacted in the HI test with Russian spring-summer encephalitis (RSSE), Central European encephalitis (CEE) virus strains, Skalica and Langat viruses. No reaction was observed with Powassan, Karshi, and Royal Farm viruses. MoAb type 2 reacted in the CF test with all members of tick-borne encephalitis complex except the Powassan, Karshi, and Royal Farm viruses.

Peroral immunization of adult white mice with the Skalica strain from the tick-borne encephalitis virus complex.

Adult white mice immunized perorally with the infectious Skalica strain from the tick-borne encephalitis (TBE) virus complex did not show any clinical symptoms of illness. 56% of experimental animals immunized with two doses of the Skalica virus (the titer of virus was 6 x 10(10) LD50) were protected against the challenge with the Hypr strain of TBE virus. All mice immunized with the Skalica virus and having haemagglutination-inhibiting antibodies higher than 1:80 survived the challenge with the given dose of virulent TBE virus. No differences in the immunogenicity and protectivity were observed in experimental animals infected with infectious Skalica virus by oesophageal probe, or by drinking virus-containing medium. A higher protective activity against the virulent Hypr virus was observed in adult white mice immunized subcutaneously with the Skalica virus.

Biology of tick-borne encephalitis virus.

Tick-borne encephalitis (TBE) virus is an important human pathogen belonging to the genus Flavivirus within the family Flaviviridae. The genome of the TBE virus is a single-stranded RNA (ssRNA) molecule of positive polarity encoding all the viral proteins within a single open reading frame (ORF). TBE virus shares common physical and genetic characteristic of the flavivirus genus. Two subtypes of the TBE virus have been described: (1) European, endemic in many parts of Europe and transmitted by Ixodes ricinus ticks, and (2) Far Eastern (Russian spring summer encephalitis (RSSE) virus), endemic in Far East and transmitted by Ixodes persulcatus ticks.

Non-infectious tick-borne encephalitis antigen.

After formalin treatment of sucrose-acetone antigens, prepared from different tick-borne encephalitis (TBE) virus strains, their haemagglutination (HA) activity was preserved or even higher than that of untreated antigens. Formalin-treated TBE antigen was non-infectious and thus may be recommended for routine work to avoid laboratory infections.

Comparative studies on sindbis virus strains isolated in Slovakia.

Two variants of Sindbis virus strains were distinguished according to the dextran sulphate (DS) marker. Large-plague strains freshly isolated from Cricetus cricetus and Rana ridibunda produced exclusively small plaques after DS treatment. The prototype Sindbis virus strain produced both large and small plaques after DS treatment. Kinetic haemagglutination-inhibition tests revealed a higher reactivity of freshly isolated strains than of the prototype strain. For differentiation of newly isolated strains of Sindbis virus, their sensitivity to sodium deoxycholate is recommended: a freshly isolated strain proved to be resistant to sodium deoxycholate.

Marker stability of the Skalica strain (from the tick-borne encephalitis complex) propagated in Ixodes ricinus ticks.

Ixodes ricinus larvae from the laboratory breed were infected on viraemic suckling mice inoculated with the Skalica strain from the tick-borne encephalitis complex. The strain recovered from individual nymphs on days 39 and 54 after metamorphosis had the markers (ic+, sc-, t-, v-) identical with the original Skalica strain.

Pathogenicity of the skalica strain (from the tick-borne encephalitis complex) for white mice.

Outbred white mice of different age were inoculated by subcutaneous (s. c.) route with the Skalica strain of tick-borne encephalitis virus (TBE). In the CNS of 3-days-old mice diffuse necrotizing encephalitis, abundant cytoplasmic fluorescence of viral antigen in nearly each neuron and high levels of virus (8.8 log LD50/mg tissue) were found. In 10-days-old mice, the extent of encephalitis and that of immunofluorescence in neurons were less widespread; the peak titre of the virus did not exceed 5.5 log LD50/mg brain tissue. In the CNS of 21-days-old mice the infectivity titre was either very low (1.5 log50/mg on day 3 post infection) or the virus was not detected at all. A few neurons revealed positive fluorescence of viral antigen in the basal ganglia in 1 out of 2 mice examined by day 3 post infection (p. i.). No virus was isolated from the CNS of 2-months-old mice observed for 53 days. In the CNS of 3 out of 10 juvenile mice examined histologically within 8 days post infection, minimal inflammatory changes were seen; foci of neurons showing positive immunofluorescence were not found. The failure to recover infectious virus from cultured brain tissue fragments coming from these mice confirmed the negative outcome of direct virus isolations. It is concluded that the Skalica strain was not pathogenic for juvenile mice when administered by s. c. route.

Antigenic relationships among viruses of the tick-borne encephalitis complex as studied by monoclonal antibodies.

Tick-borne encephalitis (TBE) monoclonal antibodies showed haemagglutination-inhibiting (HI) activity against viruses belonging to the TBE complex except of Powassan virus. The HI titre with Kyasanur forest disease virus was lower than with tick-borne encephalitis virus, when monoclonal antibodies were incubated with the antigen at +4 degrees C for 30 min. Langat virus could be distinguished from other viruses of the TBE complex when the antigen was incubated with monoclonal antibodies at +4 degrees C for 18 hr. A close antigenic relationship was demonstrated between tick-borne encephalitis, louping-ill, Negishi and Omsk haemorrhagic fever viruses.

Phenotypic mixing between vesicular stomatitis and Uukuniemi viruses.

The population of vesicular stomatitis virus (VSV) which reproduced in cells preinfected with Uukuniemi virus (UUK) contained a proportion of VSV (UUK) pseudotypes. The virions containing the VSV genome were resistant to anti-VSV serum and neutralized with anti-UUK serum. In addition to previous reports on phenotypic mixing of different families of enveloped viruses, the combination of rhabdovirus surface antigen with bunyavirus genome is described.

Comparison of skalica, Hypr, and Langat viruses by kinetic haemagglutination-inhibition test.

The Skalica virus has been compared with Hypr and Langat viruses by kinetic haemagglutination-inhibition (HI) test. Using Hypr antigen, differences were observed between Skalica, Hypr, and Langat viruses. By the use of Skalica antigen, a close relationship between Hypr and Skalica viruses was detected, however, it was possible to differentiate the Langat virus. When Langat antigen was tested, a close relationship among all the three viruses was found.

Isolation and identification of group B arboviruses from the blood of birds captured in Czechoslovakia.

Three West Nile (WN) virus strains were isolated from the blood of birds (Tringa ochropus, Vanellus vanellus and Streptopenia turtur) captured in south Slovakia. One strain of tick-borne encephalitis (TE) virus was isolated from the blood of Tringa ochropus captured in south Moravia.

Influence of tick-borne encephalitis and West Nile viruses on the chromosomes of pig kidney cells.

Changes of the mitotic index (MI) were studied in pig kidney (PS) cells infected either with tick-borne encephalitis (TBE) virus strains Hypr and Ir-32, or with West Nile (WN) virus prototype strain, strains K-99 and E-13. The cell division was arrested by the infection (metaphase barrier). The effect of TBE virus strains was manifested by the appearance of lagging chromosomes while the action of WN virus strains by colchicine--like metaphases. The prototype TBE virus strain Hypr affected the chromosomes and mitotic apparatus of PS cells less markedly than did the freshly isolated Ir-32 strain.

Studies on the effect of 9-(R, S)-(2,3-dihydroxypropyl)adenine on tick-borne encephalitis virus.

Peroral treatment with 9-(R, S)-(2,3-dihydroxypropyl) adenine did not protect mice infected with tick-borne encephalitis (TBE) viruses (strains Hypr and Ir13) when the drug was administered at the time or infection and/or up to day 2 after infection. The analogue inhibited the haemagglutination activity of the Skalica strain in vitro.