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Biomedical subjects

V Nikolić

Publications and source records attributed to V Nikolić.

At least 19 recordsLinked to original sources
PubMed2000

Interferometry in the assessment of biomechanical features of the masticatory system hard segments.

Biomechanical studies have found wide application and solved many problems in dental medicine. An interdisciplinary approach has allowed an ever-faster progress in the field. The aim of this study was to point out the advantages of holographic interferometry. With the use of this method, the study object is observed as a whole rather than as a substrate, thus providing a three-dimensional holographic image visualizing the load transmission from one jaw to another, tooth pressure against the alveolus, and strain of Sharpey's fibers, and yielding precise data on deformities, dislocations and force distribution.

Anthropometry↗
PubMed1999

Osteogenic effect of a gastric pentadecapeptide, BPC-157, on the healing of segmental bone defect in rabbits: a comparison with bone marrow and autologous cortical bone implantation.

Gastrectomy often results in increased likelihood of osteoporosis, metabolic aberration, and risk of fracture, and there is a need for a gastric peptide with osteogenic activity. A novel stomach pentadecapeptide, BPC-157, improves wound and fracture healing in rats in addition to having an angiogenic effect. Therefore, in the present study, using a segmental osteoperiosteal bone defect (0.8 cm, in the middle of the left radius) that remained incompletely healed in all control rabbits for 6 weeks (assessed in 2 week intervals), pentadecapeptide BPC-157 was further studied (either percutaneously given locally [10 microg/kg body weight] into the bone defect, or applied intramuscularly [intermittently, at postoperative days 7, 9, 14, and 16 at 10 microg/kg body weight] or continuously [once per day, postoperative days 7-21 at 10 microg or 10 ng/kg body weight]). For comparison, rabbits percutaneously received locally autologous bone marrow (2 mL, postoperative day 7). As standard treatment, immediately after its formation, the bone defect was filled with an autologous cortical graft. Saline-treated (2 mL intramuscularly [i.m.] and 2 mL locally into the bone defect), injured animals were used as controls. Pentadecapeptide BPC-157 significantly improved the healing of segmental bone defects. For instance, upon radiographic assessment, the callus surface, microphotodensitometry, quantitative histomorphometry (10 microg/kg body weight i.m. for 14 days), or quantitative histomorphometry (10 ng/kg body weight i.m. for 14 days) the effect of pentadecapeptide BPC-157 was shown to correspond to improvement after local application of bone marrow or autologous cortical graft. Moreover, a comparison of the number of animals with unhealed defects (all controls) or healed defects (complete bony continuity across the defect site) showed that besides pentadecapeptide intramuscular application for 14 days (i.e., local application of bone marrow or autologous cortical graft), also following other pentadecapeptide BPC-157 regimens (local application, or intermittent intramuscular administration), the number of animals with healed defect was increased. Hopefully, in the light of the suggested stomach significance for bone homeostasis, the possible relevance of this pentadecapeptide BPC-157 effect (local or intramuscular effectiveness, lack of unwanted effects) could be a basis for methods of choice in the future management of healing impairment in humans, and requires further investigation.

Animals↗
PubMed1998

Detection of CYP2D6*3 and 2D6*4 allelic variants by PCR-restriction fragment length polymorphism.

The mutant of CYP2D6*3 allele with A2637 deletion in exon 5 and the mutant of CYP2D6*4 allele G1934-->A, splice site defect are among the most common polymorphic alleles of CYP2D6 gene, resulting in a decreased or no activity of CYP isoenzyme. In this study, a reliable polymerase chain reaction-restriction fragment length polymorphism method for identification of CYP2D6*3 and CYP2D6*4 alleles was used to investigate the genotype and phenotype prevalence in the groups of normal controls, and of cirrhosis and cancer patients. The results showed none of 36 controls genotyped for 2D6*3 and 2D6*4 allele to have the 2D6*3 allele with frameshift mutation in exon 5, while 33% (n=12) were found to bear the 2D6*4 allele with G to A mutation at the intron 3-exon 4 junction. In breast cancer patients (n=35) genotyped for 2D6*3 and 2D6*4 alleles, none with 2D6*3 allele was found either, but 60% (n=18) were found to bear the 2D6*4 allele. In patients with head and neck squamous cell cancer, there was only one subject with 2D6*3 allele and he was heterozygous. Among them, as many as ten (40%) patients were found to bear 2D6*4 allele. In the cirrhosis group, none of the patients was found to have the 2D6*3 allele, while the CYP2D6*4 allele was found in 23% (n=6) patients. The phenotype predicted according to the genotype was as follows: in the control group, 3% of individuals were identified as poor metabolizers, 70% as extensive metabolizers, and 27% as heterozygote extensive metabolizers. In the group of breast cancer, 7% of the patients were identified as poor metabolizer, 57% as extensive metabolizer and 36% as phenotype. In squamous cell cancer and cirrhosis patients, the incidence of poor metabolizer was zero, and of heterozygotes extensive metabolizer 42% and 31%, respectively.

Alleles↗
PubMed1998

Influence of pyridine and urea on the rat brain ATPase activity.

The neurotoxicity of pyridine and urea was investigated in respect to their ability to alter the activity of synaptosomal membrane Na+/K(+)-ATPase and Mg(2+)-ATPase. In vitro treatment with pyridine and urea stimulated Na+/K(+)-ATPase activity in a dose-dependent manner up to 40% and 60%, respectively. Mg(2+)-ATPase activity increased up to 40% after pyridine treatment, while urea had no effect at all. The neuroactive potencies of pyridine and urea were evaluated by estimating parameters Km and delta Vmax for enzyme stimulation, as well as Hill coefficient to estimate the levels of cooperativity for pyridine and urea binding. The results suggest that pyridine stimulates both enzymes, probably by interacting with some neuronal membrane components, and altering the lipid micro-environment of the ATPases. In contrast, urea stimulates the Na+/K(+)-ATPase only, assumingly by acting on it directly or via some other regulatory mechanism. Stimulation of Na+/K(+)-ATPase and Mg(2+)-ATPase by the substances tested and subsequent alteration of neuronal cell functioning could contribute to the CNS dysfunction upon chronic exposure to pyridine and urea.

Animals↗
PubMed1997

Recurrent hemolytic uremic syndrome with hypocomplementemia and intestinal lymphangiectasia.

A 23-year old male patient had eight distinct episodes of hemolytic uremic syndrome (HUS) between 8.5 and 15 years of age, five of them accompanied by hypocomplementemia. In the further course, severe hypertension, renal insufficiency as well as protein-losing enteropathy due to intestinal lymphangiectasia developed, whilst hypocomplementemia persisted. The association of recurrent HUS with hypocomplementemia and intestinal lymphangiectasia may represent a new association within a subgroup of the atypical HUS.

Adult↗
PubMed1995

Biomechanical features of axial injuries to the lower limbs and to the pelvic ring by motor car collisions.

By frontal car collision, passengers are exposed, commonly, by dynamic deceleration force, applied to the lower limb and acting in the direction of the femoral shaft axis. This force could be transmitted from the foot, or from the knee to the hip joint, resulting in typical fractures of the femoral shaft, upper part of the femur as of the acetabulum. The authors have described radiological feature and three dimensional definition of these fractures as well as their ergonomic characteristics. The purpose of this study was to explain biomechanical etiology of acetabular and proximal fractures of the femur. This analysis may be useful in prevention of these fractures.

Accidents, Traffic↗
PubMed1994

Belgrade and Hantaan hantaviruses--the causative agents of severe haemorrhagic fever with renal syndrome in children in Serbia.

During an outbreak of haemorrhagic fever with renal syndrome (HFRS) in 1989, five children (3 girls, 2 boys, aged 6.8-16 years) with a severe form of the disease were treated; four of these were followed for 22-28 months. The main clinical features in all five patients were: fever, headache, myalgia, abdominal and back pain and vomiting; haemorrhagic syndrome was present in four children. Renal syndrome presented with severe acute renal failure in all five patients. All patients recovered. Serological confirmation by an indirect immunofluorescence assay, by enzyme immunoassay for IgM antibodies and by plaque reduction neutralization test showed infection by Belgrade virus in three and by Hantaan virus in two patients. It was not possible to differentiate these two serogroups on the basis of clinical features. This study provides further information on the circulation of different hantaviruses causing severe HFRS in Serbia.

Adolescent↗
PubMed1994

Focal glomerular sclerosis and nephrotic syndrome in spondyloepiphyseal dysplasia.

The association of a spondyloepiphyseal dysplasia and disproportionate short stature with focal glomerular sclerosis is reported in two girls. Renal disease manifested by proteinuria at the age of 2.5 and 11 years, leading to treatment-resistant nephrotic syndrome over 15 and 45 months, respectively. One patient went into end-stage renal failure shortly after nephrotic syndrome developed, the other died from sepsis. The association of spondyloepiphyseal dysplasia and focal glomerular sclerosis with nephrotic syndrome may represent a distinct disease entity.

Adolescent↗
PubMed1994

Asymmetrical modulation of immune reactivity in left- and right-biased rats after ipsilateral ablation of the prefrontal, parietal and occipital brain neocortex.

We report here on the lateralized brain immunomodulation in male Wistar rats, a phenomenon related to the rotational bias of animal and the site of cortical lesion. Rats assigned to left- and right-rotators in a cylindrical Plexiglass rotometer were subjected to the ablation of the ipsilateral prefrontal cortex (PFC), parietal cortex (PC) and occipital cortex (OC) and sensitized with bovine serum albumin (BSA) in complete Freund's adjuvant. Intact and sham-lesioned left-biased animals demonstrated increased Arthus and delayed hypersensitivity skin reactions and antibody production to BSA in comparison with corresponding right-biased animals. PFC ablation decreased humoral and cellular immune responses to BSA in left- but increased in right-biased rats. Lesioning of PC decreased humoral immune reactions in left- but increased in right-rotating animals. OC ablation failed to produce immunological abnormalities. These results suggest that immunopotentiation is associated with the left neocortex, and immunosuppression with the right neocortex. The prefrontal cortex appears to be particularly associated with immune reactions.

Animals↗
PubMed1994

[Surgical aspects of liver resection based on 5 years' data].

From 1988 to 1993 thirty liver resections were performed in thirty patients. Eight were operated for suffering from hepatocellular carcinoma, four from metastasis of colon's adenocarcinoma, five for great hemangiomas and the rest for focal liver changes. Right lobectomy was performed in six cases, as well as two trisegmentectomies and two left lobectomies while segmentectomies in the rest. Periopretive mortality occurred in two cases as two patients died because of postoperative thrombosis of vena portae and massive gastrointestinal bleeding. Recidive of malignant tumors was established in five patients after year and in other five till the second year. Benign tumors are without recidives. Later resection is a safe procedure with a considerable selection of patients, with use of latest technical conveniences, application of grafts on branches of vena portae and with routine application of intraoperative ultrasonography. The paper contains diagnostical postulates, surgical techniques and anatomic and morphologic types of resection.

Female↗
PubMed1994

[Possibilities of interventional ultrasonography in the differential diagnosis of pancreatic malignancy].

Pancreatic carcinoma is one of the most aggressive visceral malignancies with lethal ending in 99% of cases. Although diagnostic methods make a great progress, the world epidemiologists consider this disease to be increasing. The main reason for this is probably the problem of making early diagnosis. Various diagnostic techniques including ultrasonography often make no difference between benign and malignant changes. The aim of this paper is to consider values of pancreatic functions under the control of ultrasound in a group of patients. The examination included patients with evident pancreatic changes. By cytopathologic analysis of the gathered material clear diagnosis was made. In most cases malignancy was established. The aim of diagnostic examination is to make diagnosis as early as possible, using minimal number of tests which should be the least invasive and traumatic for patients. As a diagnostic method ultrasonography is fast and simple which provides better chances for patients with pancreatic carcinoma.

Adult↗
PubMed1994

[The hyperventilation syndrome in children].

Hyperventilation syndrome is not a rare disorder present primarily in children, but in adolescents too. It points to anxiety in children with or without family problems. The clinical picture is polymorphous and often without a clear connection with hyperventilation. That is why it is necessary for the physician to be aware of this problem in practice. The diagnosis is made on the basis of clinical picture and hyperventilation provocative test, when one expects this disorder might occur. We have reported five cases of children with this syndrome, with a special review concerning clinical picture and the way which led to the confirmation of diagnosis.

Adolescent↗
PubMed1994

Myocardial bridging of the left anterior descending coronary artery in monkey hearts.

The presence of myocardial bridges over the left anterior descending coronary artery (LAD) has been studied in 55 monkey (Cercopithecus aethiops) hearts. The resemblance between the Cercopithecus LAD and the one in humans has been revealed. Cercopithecus LAD was the most frequently (70.9%) overbridged artery. The bridges were usually single. Only in 2 hearts (3.6%) LAD was overbridged by 2 MB. Their length varies from 0.5 mm to 31.6 mm (average 11.7 mm). No statistically significant sexual differences in the incidence and length of MB have been reported. Atherosclerotic lesions have been reported in overbridged parts of the vessel as well as in the subepicardial ones. Intimate correlation between the presence of myocardial bridges and atherosclerosis could not be suggested.

Animals↗
PubMed1993

Locus ceruleus and immunity. I. Suppression of plaque-forming cell response and antibody production in rats with lesioned locus ceruleus.

Earlier research had demonstrated that lesions placed in different brain structures may alter the immune responsiveness. Norepinephrine is one of neurotransmitters which plays a role in immune reactions, and the locus ceruleus represents the largest group of norepinephrine-containing neurons in the brain. The present study concerns, therefore, the relationship between the locus ceruleus and humoral immune reactions. For this purpose, rats with electrolytically induced lesions in locus ceruleus were used in the study. Locus ceruleus-lesioned animals showed a decreased ability to produce hemolysin-releasing cells, hemagglutinins, and antibodies to bovine serum albumin. In brain-lesioned rats, thymus tended to the smaller in size, and there was a depletion of CD4+ helper/inducer lymphocyte population in the peripheral blood.

Agglutinins↗
PubMed1993

Locus ceruleus and immunity. II. Suppression of experimental allergic encephalomyelitis and hypersensitivity skin reactions in rats with lesioned locus ceruleus.

Rats with lesions restricted to the locus ceruleus were tested for immune inflammatory reactions. In these rats, Arthus and delayed skin hypersensitivity reactions to bovine serum albumin and old tuberculin were suppressed. The ablation of locus ceruleus completely inhibited the development of clinical signs of experimental allergic encephalomyelitis, markedly diminished the occurrence and intensity of lesions in the central nervous system, and significantly reduced the production of antibody against the rat brain myelin basic protein. These results establish a link between the locus ceruleus and immune inflammatory reactions in the rat.

Animals↗
PubMed1993

Brain-applied magnetic fields and immune response: role of the pineal gland.

In an attempt to clarify the mechanisms underlying immunopotentiation induced by prolonged exposure of the rat brain to static magnetic fields, and to evaluate the role of the pineal gland in that phenomenon, experiments were carried out on the following groups of adult rats (maintained under a 12 hr light/12 hr dark photoperiod): pinealectomized rats (Px); rats with micromagnets implanted to the occipito-parietal region of the skull (M); rats pinealectomized and implanted with micromagnets to the skull (PxM); sham-pinealectomized rats with non-magnetic beads implanted to the occipito-parietal area of the skull (ShPxMx); and intact controls (IC). Twenty-one days after surgery, animals of all groups were immunized with sheep red blood cells and tested for plaque forming cell (PFC) response and serum hemagglutinin level. Humoral immune reactions decreased significantly in Px rats, while increased markedly in M rats in comparison to the ShPxMx and IC controls. Compromised immune function induced by pinealectomy was restored by prolonged exposure of the brain to magnetic fields (PxM rats). Thus reconstituted immune responsiveness in PxM rats reached the level observed in controls, but was lower than that in M rats. The results imply that magnetic fields applied to the rat brain may exert their immunoenhancing activity in the absence of the pineal gland. However, this activity of magnetic fields is more pronounced in the presence of the pineal organ. The latter finding suggests the involvement of the pineal in the immunopotentiation induced by magnetic fields, but does not imply that magnetic fields operate solely via the pineal gland.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[Habituation and effects of protein synthesis blockers on neuronal activity in the cerebral sensorimotor cortex in rabbits].

The investigation of brain functions has been for many years an exciting and at the same time a very complex and enigmatic domain of research. In our experiments we followed the occurrence of habituation, a simple form of learning, during a peripheral light stimulation, in sensorimotor cortex neurons of rabbits. In the majority of the mature neurons habituation occurred with repeated light stimulations with same features, while in immature rabbits it was less frequently observed and was slower. Since in basic patterns of habituation and learning, cell protein plays a significant role, we followed the effects of protein synthesis blockers in the process of training and electrogenesis. Microiontophoretic application of actinomycin D and cyclohexamide compromised the occurrence of habituation in high number of registered neurons, while the application of a neurotransmitter, acetyl choline, promoted habituation in the sensorimotor brain cortex neurons of immature experimental animals.

Acetylcholine↗