Biomedical subjects

M Obradović

Publications and source records attributed to M Obradović.

At least 19 recordsLinked to original sources

PubMed1998

The acidophilic nature of neuronal Golgi impregnation.

The mechanisms of Golgi impregnation of neurons has remained enigmatic for decades. Recently, it was suggested that divalent (di)chromate anions play a role in the Golgi impregnation process. Therefore, we incubated slices of (para)formaldehyde-fixed rat brain tissue in solutions of potassium (di)chromate, phosphate, chloride or nitrate at pH 6 or 7. Slices were then immersed in solutions of silver nitrate and processed for light microscopical analysis. At pH 6, dichromate probes resulted in dense and homogeneous impregnation of neuronal cytoplasm (typical impregnation). At pH 7, chromate probes showed solely partial cytoplasmic and heavy nuclear-region neuron impregnation (atypical impregnation). Phosphate probes at pH 6 resulted in typical impregnation, whereas at pH 7 phosphate probes gave atypical impregnation. Both at pH 6 and 7, chloride and nitrate probes did not yield any Golgi impregnation. These findings confirmed the pH-dependence of silver-chromate Golgi impregnation as well as the correctness of corresponding acidic silver-phosphate impregnation. Our study revealed a previously unknown, strong anion-dependence of Golgi impregnation, suggesting that hydrogenated monovalent anions are carriers of the neuron impregnation.

Animals↗

PubMed1997

Incidence and role of apoptosis in myelodysplastic syndrome: morphological and ultrastructural assessment.

By application of morphological and ultrastructural methods for identification of apoptosis, we analyzed the incidence of morphologically evident apoptosis in the bone marrow of 30 patients with myelodysplastic syndrome (MDS), and in the bone marrow of 12 healthy individuals. According to FAB classification, out of 30 patients, eight (26.6%) had refractory anemia, three (10%) had refractory anemia with ringed sideroblasts, 14 (46.6%) had refractory anemia with excess of blasts and two (6.8%) had refractory anemia with excess of blasts in transformation. Three patients (10%) had chronic myelomonocytic leukemia. Cells in apoptosis were examined on semithin slides and expressed as the apoptotic index (AI) (percent counted on at least 1000 cells). An overall increase in apoptosis in patients with MDS was found (median AI in patients vs controls, 3.13% vs 1.05%, P < 0.01 by Mann-Whitney U test). Also, negative correlation between AI and white blood cell count was found (linear r= -0.53, or Spearman rank R= -0.52, both P < 0.01). In patients with evident karyotype changes AI was not higher than in patients with normal karyotype. This suggests that discrete alterations in apoptosis are present even in karyotypically 'normal' clones. Our results strongly support the hypothesis that apoptosis has a role in ineffective hematopoiesis and may be a mechanism responsible for the paradox of hypercellular bone marrow and peripheral blood pancytopenia in MDS.

Anemia↗

PubMed1993

[Epidemiologic characteristics and serologic findings in erythema migrans].

Our three-year research covered 417 patients with erythema migrans, of both sexes and all age groups. Among them 87.3% had a history of tick bite. Average attachment of tick to a patients skin was two days. Diameter of erythematous lesions was 1-50 cm (with an average of 15.1 cm). Magnitude of the lesion does not correlate with the further development of the Lyme disease. IFA test detected antibodies against Borreliae burgdorferi in 27.0% of our patients.

Adult↗

PubMed1993

[Lyme disease in human medicine].

Six years of investigations of Lyme disease in our country has offered an opportunity for better understanding of this "new" illness, which is both a medical and a health problem. The number of patients with Lyme disease is found to be similar to the number of patients in other countries. Human infections occur in different areas, rural and urban settings. A high level of collected ticks with Borrelia burgdorferi, suggests a considerable risk of human infection after a tick bite. Difficulties in diagnosing of Lyme disease are connected with different clinical symptoms and signs of the illness a poor health service personnel knowledge og the disease, and the lack of reliable and more convenient laboratory tests for confirmation of the diagnosis. A team work and a multidisciplinary aspect in the investigations and the routine work provide a solid base for a better understanding and gathering much more experience in this field. The individual protection remains a basic control measure, and each person can do the most for self protection. An activity in the health education is also of a very great importance.

Humans↗

PubMed1993

[Ecology of Borrelia burgdorferi].

Much still remains to be understood about ecology of Borrelia burgdorferi which is transmitted by a number of ticks belonging primarily to the Ixodes complex, known to feed on different animal hosts and humans. This article pretends to be a review of previous knowledge of Borrelia burgdorferi ecology. Special emphasis is placed on the preliminary results of an investigation conducted in Yugoslavia on the risk of developing lyme borreliosis after a tick bite (Ixodes ricinus). Lyme borreliosis was studied prospectively in 147 persons with tick fastened on them. Dark-field microscopic examination of tick mitgut revealed that 11 (7.9%) od 147 Ixodes ricinus were infected with Borrelia burgdorferi. Lyme borreliosis was demonstrated in only one (0.6%) of all persons bitten by ticks infected with Borrelia burgdorferi. In conclusion, these preliminary data indicate that in Yugoslavia lyme borreliosis infrequently occurred after a tick bite.

Animals↗

PubMed1993

[Vectors of Borrelia burgdorferi].

During the period 1990-1992-5,915 ticks were collected and identified in the area of Belgrade. Identification has shown that 99.8% were Ixodes ricinus and 0.2% Dermacentor marginatus. Infection with Borrelia burgdorferi was found in 27.0% to 31.7%. Females were more often infected than males and nymphs more often than larvae. Tick infection was at lowest degree in parks, little bit higher in woods and highest in mixed park-wood areas. Out of 28 locations, six can not be defined as foci of Lyme borreliosis, two are defined as potential foci and 20 as active foci of Lyme borreliosis. In a three year period we have isolated Borrelia burgdorferi in five occasions; in one occasion from ticks collected in Barajevo and in four occasions from ticks collected in Kosutnjak.

Animals↗

PubMed1993

[A theoretical model for the study of Lyme borreliosis].

This article is a short review of: a) development of theory on natural foci of communicable diseases in man, b) methodological approach to the investigation of natural foci, e.g. theoretical model in their investigation, and c) the use of theoretical model in the investigation of Lyme borreliosis. A great number of multidisciplinary studies on natural foci zooanthroponoses conducted through many years, in which ecological approach and numerous methods were applied, commencing from studies of the processes at the level of molecules, genes, cells, tissues, organismus, populations and species, contributed to the knowledge that epizootical process of natural foci of zooanthroponoses is almost an ideal natural model. Its investigation allows the establishment of the rules of epidemiological process which, for many reasons (ethical above all), is not accessible for experimental studies. On these principles a general block model has been worked out, which serves for the estimation of epidemiological manifestations of natural foci zooanthroponoses, and which, applied to Lyme borreliosis, enables the determination of active and potential foci and the estimation of the degree of risk of man infection in determined foci. Data obtained in such a way allow planning and application of adequate preventive measures.

Disease Reservoirs↗

PubMed1993

[Exposure to Ixodes ricinus bites among soldiers].

Results of an investigation on the exposure to tick bites among soldiers in 6 permanent army structures on the territory of Belgrade are shown. Four army structures were found to be active foci of Lyme borreliosis. Infection rates among Ixodes ticks were from 10% in urban structures to 42.1% in rural structures. Exposure of soldiers to tick bites was the largest in rural army structures--3.40%, while in urban army structures it was 0.14%. Among 38 tick bitten army members, 1 developed clinical manifestation as Lyme borreliosis (2.6%).

Animals↗

PubMed1993

[The first isolation of Borrelia burgdorferi in Apodemus flavicollis in Yugoslavia].

Small rodent species, as well as their ectoparasitic fauna, and the presence of Borrelia burgdorferi in their blood and internal organs (liver and spleen) was investigated, at two locations (Kosutnjak, Lipovicka suma) in Belgrade. Animals were caught between September 15-17, 1992. On location Kosutnjak two Apodemus flavicollis were trapped and Borrelia burgdorferi was isolated from the spleen of one of them. On location Lipovicka suma 13 rodents were trapped as follows: 10 Apodemus flavicollis, 2 Apodemus agrarius and one Mus musculus. In these the presence of Borrelia burgdorferi was not determined. Ectoparasits Ixodes ricinus, Nesopyllus fasciatus and Haemogamasus spp. have been found. The location Kosutnjak can be considered as an active focus of lyme borreliosis.

Animals↗

PubMed1991

[Hemorrhagic fever with renal syndrome--etiology].

HFRS was confirmed serologically in two patients, who were infected in the natural focus near Zupanja. Using the bigger number of virus antigens in indirect immunofluorescent antibody test, afterwards was proved the agent could be classified into the serotype 3 of Hantaviruses, and antigenically is identical with virus NE (strain Hällnäs), respectively Yugoslav isolate "Vranica". Serotype differentiation of the agent in patient who were infected in the area of Igman, near Sarajevo, has not been performed by the same test. There was assumed a possibility for circulation of "new", up to now non-identified, serovariant of Hantaviruses in this natural focus.

Antigens, Viral↗

PubMed1989

Epidemic hemorrhagic fever with renal syndrome in Yugoslavia, 1986.

An epidemic of hemorrhagic fever with renal syndrome (HFRS) occurred in Yugoslavia May-November 1986; all Republics and Provinces were involved. Serum samples were received from 260 of 276 persons with symptoms clinically compatible with a diagnosis of HFRS. Presumptive infection with a hantavirus was determined serologically for 161 of these. Many patients with serious clinical pictures, including severe renal insufficiency and shock, were hospitalized; 11 died. Indirect fluorescent antibody tests with antigens of 4 hantaviruses (Hantaan, Fojnica, Puumala, and the Vranica strain of Puumala virus) showed that greater than 1 serotype was circulating during this epidemic. Hantavirus antigens were detected in the lungs of 86 of 302 (28.5%) wild-caught small mammals.

Disease Outbreaks↗

PubMed1989

Hemorrhagic fever with renal syndrome in Yugoslavia: antigenic characterization of hantaviruses isolated from Apodemus flavicollis and Clethrionomys glareolus.

Hantavirus antigens were detected in lung tissues of 8/113 Apodemus flavicollis and 2/17 Clethrionomys glareolus captured in 1984 in Fojnica, a region of Yugoslavia endemic for hemorrhagic fever with renal syndrome; hantavirus antigens were not detected in lung tissues from 126 other mammals collected in Fojnica. Three hantaviruses, 2 from A. flavicollis and 1 from C. glareolus, were isolated directly in Vero E6 cells and were partially characterized. The isolates from A. flavicollis, designated Fojnica virus, were antigenically similar but not identical to Hantaan virus strain 76-118, whereas the isolate from C. glareolus was antigenically indistinguishable from Puumala virus, strain Hällnäs B1. These data are consistent with previous studies that indicate the existence of at least 2 hantavirus serotypes in Yugoslavia.

Animals↗

PubMed1988

Hemorrhagic fever with renal syndrome in Yugoslavia: detection of hantaviral antigen and antibody in wild rodents and serological diagnosis of human disease.

Lung tissues from 547 rodents and 26 insectivores captured between 1981 and 1984 in central Bosnia (Fojnica) and central Serbia (Cacak), 2 regions known to be endemic for hemorrhagic fever with renal syndrome (HFRS), were examined for hantaviral antigen by the indirect immunofluorescent antibody technique. Antigen was detected in 17/231 Apodemus flavicollis, 3/187 A. sylvaticus, 1/46 A. agrarius, 4/32 Mus musculus, and 3/28 Clethrionomys glareolus. In addition, antibodies against Hantaan and Puumala viruses were found in serum pooled from 2 C. glareolus captured in Fojnica and 6 Pitimys subterraneus caught in Cacak. Sera of 27 HFRS patients from different parts of Yugoslavia were tested against 3 serotypes of hantavirus. Patients from Bosnia and Serbia had highest titers against Hantaan virus, while patients from Croatia had highest titers against Puumula virus, the agent of nephropathia epidemica.

Animals↗

PubMed1987