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Biomedical subjects

B Dimitrijević

Publications and source records attributed to B Dimitrijević.

At least 19 recordsLinked to original sources
PubMed2004

Localization of recognition site between transforming growth factor-beta1 (TGF-beta1) and TGF beta receptor type II: possible implications in breast cancer.

Although overexpression of TGF-beta1 protein has been demonstrated in advanced breast cancer (BC) patients, as well as in other solid tumours, the molecular mechanism of this process remains obscure. This paper proposes that a genetic/epigenetic alteration might occur in the TGF-beta1 gene, within the region coding for the recognition site with TGFbeta receptor type II, leading to a disruption of the ligand-receptor interaction and triggering the TGF-beta1 cascade-related BC progression. To establish the operational framework for this hypothesis, in the present study, this recognition site was identified by the Informational Spectrum Method (ISM) to comprise two TGF-beta1 peptides (positions 47-66 aa and 83-112 aa) and one receptor peptide at positions 112-151 aa of the extracellular domain of the receptor (TbetaRIIM). The TbetaRIIM locus was further evaluated by ISM-derived deletion analysis of the TbetaRII sequences. To provide experimental support for the proposed model, a pilot study of plasma TGF-beta1 analysis was performed in advanced BC patients (n = 8). Two commercial ELISA assays, one with specific alphaTGF-beta1 MAb (MAb) and other with TbetaRIIM as the immobilized phase, revealed pronounced differences in the pattern of plasma TGF-beta1 elevation. In MAb-profile, the TGF-beta1 increase was detected in 7 of 8 patients, whereas analogous TbetaRIIM-profile revealed the elevation in 3 of 8 patients, taking a 50% of maximal elevation as the cut-off value. These findings are consistent with the proposed aberration of TGF-beta1 ligand within the TbetaRII recognition site. Summarizing, this model system is a good starting point for further genetic studies, particularly on genetic/epigenetic alterations of sequences involved in TGF-beta1 and TbetaRIIM interaction, with putative prognostic value for breast cancer.

Amino Acid Sequence↗
PubMed2000

Hematological toxicity associated with tiazofurin-influence on erythropoiesis.

In this study hematological toxicity was analyzed after the single and repeated applications of tiazofurin (TZF). Cellularity of bone marrow, spleen and peripheral blood was examined, spanning the period of fifty days after the initial application. Analysis of hematological parameters was performed by slightly modified conventional techniques. The fraction of erythroid series was monitored during the experiment. Presented data describe kinetics of damage and recovery of hemopoietic tissue. Our results indicate that the effect of tiazofurin on cellularity of bone marrow and spleen and on erythropoiesis is reversible and dose dependent within tested dose range and therapeutic regimes. Twenty days after the application normal function of hemopoietic tissues was restored. This approach and results can be useful in defining the timing for sequencing and combination therapy with tiazofurin.

Alopecia↗
PubMed1998

A dental implant: aluminium trioxide exhibited no effect on mouse reproductive and mutanogenic potential.

Several diseases as well as trauma can affect the composition and integrity of periodontal tissues leading eventually to the destruction of connective tissue matrix and cells, loss of attachment and resorption of alveolar bone, often followed by tooth loss. Replacement of the missing tooth could then be provided by endosseous dental implants healing in a form of osseo- or fibrosteal integration to the alveolar bone. Aluminium oxide ceramics, a form of endosseous implant, allows osseointegration type of healing and has demonstrated excellent biocompatibility. However, potential aluminium toxicity has been implicated in the pathogenesis of a number of clinical disorders and for this reason we examined the reproductive and mutagenic effect of aluminium trioxide ceramic implant in experimental mice. 720 female and 45 fertile male BALB-cAn NCR mice were included in the study. 3 experimental groups of fertile male mice (15 for each group) were treated with an intraperitoneal injection of aluminium trioxide (1 g/ kg of body weight, group I), with ethyl-methane-sulphonate as a positive control (200 mg/kg, group II) and with Tween-80 (10 mg/kg as a negative control, Group III). Each of the labeled male mice fertilized previously uncoupled female mice during 8 weeks (a pair per week) to facilitate appropriate pre- and post-meiotic conditions of spermatogenesis to occur. Female mice were sacrificed with cervical dislocation at day 13 after fertilization. Immediately upon sacrifice the uterus was removed and the number of alive and healthy, or alive but mutated and/or dead embryos was computed to determine the dominant lethal or mutagenic effect. Animals treated with aluminium trioxide demonstrated similar effects on the reproductive and mutagenic capacity as the negative control, whereas the animals treated as positive controls exhibited significantly reduced reproductive and mutagenic capacity. Collectively, we concluded that aluminium trioxide has a very low rate of embryonal mortality and mutagenicity in mice. This finding is in general agreement with the biocompatibility of aluminium trioxide as an implant material.

Aluminum Oxide↗
PubMed1994

High incidence of H-ras oncogene mutations in squamous cell carcinoma of lip vermilion.

Nine specimens of well-differentiated squamous cell carcinoma of the lip vermilion have been analyzed for the presence of H-ras oncogene mutations, using the technique of hybridization with synthetic oligonucleotide probes on in vitro amplified tumour DNA. Five specimens harbored mutations: four in codon 12 and one in codon 13. This high incidence (55%) of mutated H-ras genes suggests that their activation may play an important role in lip tumour development and may be connected to the exposure to chemical and/or physical carcinogens.

Aged↗
PubMed1994

Effects of a modified CMF treatment (cyclophosphamide, methotrexate and 5-fluorouracil) on hematopoietic tissues and Yoshida sarcoma in rats.

Effects of a modified CMF treatment on hematopoietic tissue and an implanted tumor were studied in rats. The modification of the treatment refers to the application of cyclophosphamide 24 h after methotrexate and 5-fluorouracil. The study was done on Wistar rats bearing Yoshida sarcoma in the ascites form. The controls were a) untreated animals bearing the tumor or b) treated conventionally with the 3 cytostatics and c) tumor-free animals under either conventional treatment or d) modified treatment. We examined survival, the appearance of metastases, and the regeneration of hematopoietic tissues. Improved survival, the absence of metastases, and improved regeneration of hematopoietic tissues was observed when modified CMF treatment was applied. These results support the importance of sequencing cytostatic protocols for basic hematological determinants and anti-tumor activity.

Animals↗
PubMed1994

[Immediate prosthetic reconstruction after resection of the upper jaw].

In order to determine the right time when appliance should be applied to the patient after partial, subtotal or total resection of the maxilla, represent cases treated during a six year period at the Clinic of Maxillofacial Surgery of the Stomatology Faculty in Belgrade. In 11 operated patients the appliance was applied immediately after surgery and tamponade of postresection activity cavity. In 46 patients operated at other clinics it was applied more than month after surgery. Thus, 57 patients received immediate prosthetic reconstructive treatment. According to criteria of adaptability considering new appliances major differences could be observed among different groups of patients. 57 patients recovery was normal, while in 4 adaptability was slower. In 12 referral cases not a single case of normal adaptability was registered. 4 patients demonstrated slower adaptability, while in 8 patients severe adaptability problems were registered.

Adolescent↗
PubMed1994

[Surgical and prosthetic reconstruction of post-tumor defects of the face (case report)].

This paper shows a combination of methods in treatment of a facial post tumorous defect. Simultaneous surgical and prosthetic reconstruction was used when treating ablation of the facial basal cell carcinoma in a 70 year old female patient. When planning this surgery the next must be taken into consideration: the age of the patient, general health condition and the size and type of the defect, especially of the bone structures. It means that collaboration between the surgeon and prosthetic is of great importance. In this way a very fast facial rejuvenation can be achieved, even in large defects which enables not only healing but further social rehabilitation of such patients too.

Aged↗
PubMed1992

Surgical versus conservative treatment of unilateral condylar process fractures: clinical and radiographic evaluation of 80 patients.

Treatment results of 26 surgically and 54 conservatively treated unilateral condylar process fractures were investigated by standardized clinical examination and by evaluation of computer-simulated graphic presentations of posteroanterior (PA) radiographs of the mandible. The radiographic evaluation compared the relation of actual reduction of the condylar process fractures with ideally reduced fractures produced on the computer. Using clinical parameters (maximal mouth opening, deviation, protrusion), no statistical differences between surgically and conservatively treated fractures were found. However, the radiographic examinations showed a statistically better position of the surgically reduced condylar process fractures.

Adolescent↗
PubMed1990

[Secondary occlusal traumatism. 1. Histopathological changes of periodontal tissues in experimental occlusal traumatism].

Six and nine months after the experimental occlusal traumatism, the following histopathological changes of periodontal tissues were observed: --Disorganisation and necrosis of the collagen fibers, abundant cellular infiltration and dilatation of the blood vasels of the periodontium; --The periodontal space was enlarged. Directions of principal collagen fibers was changed. This was especially visible in the region of transeptal fibers; --The observed periodontal changes were correlated with the duration of inflammation and occlusal trauma. The longer these factors persisted the more extensive these periodontal changes occurred.

Animals↗
PubMed1989

[Prosthetic reconstruction of the secondary deformed maxillary arch in a patient with congenital cleft].

A case history of a bilateral cleft lip and palate male patient is presented. He was operated late at the age of his twelve, without any previous orthodontic treatment. Surgical reconstruction included, lip, hard and soft palate, removal of the premaxilla, and later on the pharingoplasty. At the age of twenty years he was prosthetically rehabilitated. Nine inner telescope crowns were made in "Palador" silver alloy, and nine outer in chrom-cobalt splinted together and connected with the skeletal frame. Intermaxillary relations were recorded and established in a manner used in the construction of complete dentures, and occlusion of the teeth, too. A complete obturation of the oronasal communication in the palatomaxillary section was achieved. The patient was followed up throughout next twenty years.

Adult↗
PubMed1982

A kinetic analysis of the distinct regulatory sites on rabbit muscle pyruvate kinase.

Interaction of rabbit muscle pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) with inhibitory and activatory effectors was analyzed in terms of the Yagi-Ozawa equation. Straight-line plots obtained for L-phenylalanine + L-alanine and L-phenylalanine + L-phenylalanyl methyl ester (PheAlaOMe) indicated competition for common sites. Parabolic plots for 2-phosphoglycerate and L-phenylalanine or PheAlaOMe suggested lack of competition between these compounds. Biphasic concave plots were obtained for 2-phosphoglycerate and L-1-amino-2-phenylethyl phosphonic acid (PnPhe), and mixtures of inhibitory (L-phenylalanine, PheAlaOMe) and activatory (PnPhe, L-alanine and L-1-aminoethyl phosphonic acid (PnAla)) amino acid derivatives. The latter non-classical Yagi-Ozawa plots can be interpreted in terms of the existence of distinct regulatory sites for inhibitory and activatory ligands.

Alanine↗