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Biomedical subjects

M Popović

Publications and source records attributed to M Popović.

At least 19 recordsLinked to original sources
PubMed2004

A kinetic model of aqueous-phase alkali hydrolysis of 2,4,6-trinitrotoluene.

Alkali hydrolysis of 2,4,6-trinitrotoluene (TNT) was studied using batch experiments with starting pH values 11 and 12 in glass conical flasks covered with aluminum foil. Isothermal (25 and 40 degrees C) as well as non-isothermal experiments were conducted. Experiments starting at pH 12 resulted in >95% reduction in the concentration of TNT; those starting at pH 11 had a maximum reduction of 20-25% in TNT concentration. In all the experiments, one major stable intermediate was produced but it could not be identified. The experimental data were used to determine the overall stoichiometry of TNT and hydroxyl ions. Approximately 100 M (standard deviation 11.4) of hydroxyl ions were consistently consumed per mole of TNT. However, control experiments showed that all but 13 M (standard deviation 2) of hydroxyl ions were consumed in reactions not related to TNT. A simple kinetic model involving formation of the intermediate was proposed to account for changes in concentrations of TNT and hydroxyl ions. The rate constants and activation energies of the reactions were identified using isothermal data and the kinetic model was then used to predict the experimental data in the non-isothermal experiments reasonably well.

Alkalies↗
PubMed2003

Amniotic fluid embolism with involvement of the brain, lungs, adrenal glands, and heart.

The case of a healthy 31-year-old woman in the 40th week of second pregnancy is presented. During preparation for an emergency caesarean section, she developed an amniotic fluid embolism (AFE) with unusual and unique features. The acute onset of disease with cardiorespiratory failure with hypotension, tachycardia, cyanosis, respiratory disturbances and loss of consciousness, suggested at first a pulmonary thromboembolism, but the appearance of convulsions led to the diagnosis of AFE. The patient died after 5 days due to an untreatable brain edema. At autopsy, AFE with the usually associated disseminated intravascular coagulation was found in the lungs, brain, left adrenal gland, kidneys, liver and heart. Eosinophilic inflammatory infiltrates were found in the lungs, hepatic portal fields and especially in the heart, suggesting a specific hypersensitivity reaction to fetal antigens. Moreover, intravascular accumulation of macrophages in the lungs also favored a non-specific immune reaction to amniotic fluid constituents.

Adrenal Glands↗
PubMed2002

Scavenger activity of Allium psekemense B. Fedtsch.

In the present study the antioxidative properties of the bulbs, leaves and stalks of Allium psekemense B. Fedtsch were investigated. The activities of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, glutathione peroxidase), quantities of malonyldialdehyde, superoxide and hydroxyl radicals and reduced glutathione and also the content of total flavonoids, chlorophylls a and b, carotenoids, vitamin C and soluble proteins were determined. The results indicate that extracts from all plant organs exhibited antioxidant activity. The highest antioxidant activity was observed in the leaves. Furthermore, the ESR signal of DMPO-OH radical adducts in the presence of the leaf phosphate buffer (pH 7) extract was reduced by 54.3%.

Allium↗
PubMed2002

[The role of strictureplasty in the treatment of Crohn's disease].

Crohn's disease is pandigestive disease of unknown aethiology, with tendency to reccurrences. Until now it is impossible to heal this disease either by medical or surgical treatment. All unfavourable consequences of this disease are result of inadequate treatment of complications which are leading to systemic weakening, with further progression of morbid process. Therefore, the principle of timely and minimal invasive surgical procedure has been generally adopted. Introduced in eighties, strictureplasty is a procedure of such characteristics. During the period 1980-2001 this method was used in 1/3 of 126 patients with Crohn's disease. There were 79 strictureplaties performed, 9 long and 70 short. Out of these 42, 12(28.6%) were postoperative recurrences, and there was one case of duodenal strictureplatsty. Postoperative small bowel fistulae were not observed, and there was no mortality in this group. During the follow up period of at least 5 years, in only two cases (4.76%) some functional disturbances of digestive functions were observed, without indications for reoperation. In this article indications and details of operative technique are discussed.

Anastomosis, Surgical↗
PubMed2002

Local recurrence and five year survival after abdominoperineal resection of the rectum due to rectal carcinoma.

In the period 01.01.1991-12.31.1996, 523 operations due to rectal carcinoma were performed on the First Surgical Clinic, the Third Department for Colorectal Surgery. Most common localization of tumor was in the distal third of the rectum 65.2%. In the middle third, there were 28.9% and in the upper, intraperitoneal third 5.9%. We performed 286 low anterior stapled resections, 93 anterior resections with hand-sewn anastomosis and 144 Abdominoperineal excisions of rectum (Miles procedure). Pathohistological examination revealed adenocarcinoma in all cases. In this study we analyzed local recurrence and five-year survival after long-term follow-up in the group where Miles procedure was carried out as a potentially curative procedure (except 4.9% cased with Dukes D stage). There were 74.3% males and 23.7% females median age 59.2 years. According to Dukes classification there were 4.9% in stage A, 47.2% in stage B, 43.1% stage C, and 4.9% stage D. There were 4(2.7%) postoperative deaths. Recurrence of the disease was registered in 44 (30.5%) patients. Local recurrence alone was found in 14 (9.7%) patients, while distant spread was registered in 30 (20.8%) patients. At present, the median follow-up is at 72.9 months. Analysis by the Kaplan-Meier's test shows cumulative survival of 61%, and disease free survival of 63.4% at 60 months of the follow-up. Dukes C is associated with a very poor prognosis; survival after 60 months of follow up shows cumulative Survival of 0.35 while Dukes B has far better prognosis (0.86). Analysis of disease free survival by Dukes stage shows that Dukes C has the worst prognosis (disease free survival 0.36 after 60 months), while stage B has much better prognosis (0.84). Local recurrence analysis by the Kaplan-Meier's test shows disease free survival of 84.9% at 60 months of follow-up. Analysis of local recurrence by Dukes stage shows 1.00% disease free survival for cases in stage A, 0.94 for Dukes B and 0.66 for Dukes C, while overall comparison between groups regarding local recurrence using the Wilcoxon (Gehan) statistic shows statistically significant difference (p-0.005). There is no statistical difference between Dukes A and Dukes B cases in distribution of local recurrence.

Adenocarcinoma↗
PubMed2002

[Late results of splenectomy in patients with chronic immune thrombocytopenic purpura].

Splenectomy is definitive treatment for idiopathic thrombocytopenic purpura (ITP) because it removes both the sites of autoantibody producing cells and also the major site of platelet destruction. The purpose of this study was to evaluate long term results of splenectomised patients with ITP and to determine predictor factors for good response. A 167 patients with chronic ITP (136 females, 31 males), median aged 35 years (17-74) was splenectomised after 2 to 160 months (Median 12) from diagnosis of ITP. Indications for splenectomy were: 6 weeks of steroid therapy with platelet count below 10 x 10(9)/l or 3 months with platelet count under 30 x 10(9)/l, or treatment with prednisone above 30 mg more of 6 months to increase platelet count over 30 x 10(9)/l, or repeated relapses. Postoperative complications developed in 16 patients (9.5%), 3 of them died (1.8%) due to thromboembolism and 17 patients discontinued later controls. During follow up to 172 months (Median 62) 111/147 splenectomised patients were in remission (75.5%), 99 in complete (above 100 x 10(9)/l), 12 in partial (50-100 x 10(9)/l) and 36 patients (24.5%) were relapsed (below 50 x 10(9)/l). Remission was achieved in 79/88 patients (89.8%) with good response to prednisone before splenectomy toward 32/62 patients (51.6%) with poor response to prednisone (p < 0.01). Remission was obtained in 9/11 patients (81.8%) who responded well to intravenous immune globulin (0.4 g/kg x 5 d) and only in 1/8 who did not (p < 0.05). Higher response rate was achieved in patients under 40 years of age (81.6%) than in older ones (63.4%) (p < 0.05). No difference was shown between sex and time intervals (3, 6, 12, 24, 36 or over 36 months) from diagnosis to splenectomy. Splenectomy is an effective treatment of refractory ITP with response rate of 75.5% after median follow up of 62 months. In our patients better results on splenectomy were associated with age less than 40 years, good responses to steroid, and intravenous immune globulin.

Adolescent↗
PubMed2002

[Recurrence of immunologic thrombocytopenic purpura due to hypertrophy of retained accessory spleens].

Idiopathic thrombocytopenic purpura is an autoimmune disease in which macrophages of reticuloendothelial system, mainly in the spleen, remove platelets covered by autoantibodies from circulation. By removing the spleen 60-80% of patients are cured. Partial remission is achieved in 10-20% cases. Very few patients do not react on splenectomy. Recurrency of idiopathic thrombocytopenic purpura in a splenectomized patient after already achieved complete remission, may be caused by hypertrophy of one or more of the retained accessory spleens. We present 3 patients, 41, 23 and 44 year old, in whom splenectomy for ITP had been performed 10, 3 and 11 years earlier. After full remission which lasted 10, 2.5 and 10.5 years a full recurrency of ITP took place with signs of severe thrombocytopenia and haemorrhagic syndrome. Using ultrasonography, computed tomography and scintigraphy accessory spleen/s, were discovered. By their removal, a full remission was achieved in all 3 patients, but full favorable effect appeared approximately three months after surgery during which period additional steroid therapy was necessary.

Adult↗
PubMed2002

[Cesarean section combined with splenectomy in severely resistant immune thrombocytopenia].

Immune thrombocytopenic purpura (ITP) associated with pregnancy often involves considerable risk both for mother and child, and usually worsens in the third trimester of gestation. Pregnancy and delivery are especially difficult in patients with severe ITP (platelet count below 20 x 10(9)/L), who are resistant to prednisone and high dose intravenous immunoglobulin (IVIgG). In those cases we applied cesarean section (CS), to prevent intracranial haemorrhage due to fetal/neonatal ITP, and splenectomy at the same time as an effective therapeutic strategy for ITP. We present 5 patients (4 with chronic ITP and 1 with ITP associated with HIV infection), aged 21-35 years, with severe ITP (platelet count 2-10 x 109/L), resistant to prednisone (1-2 mg/kg), and 2/3 were resistant to IVIgG (0.4 g/kg x 5 d). Four patients with severe resistant ITP were supported with 1-2 doses of platelets from cell separator before CS and 1-3 dose during splenectomy. One patient increased platelet count to 55 x 109/L after treatment with IVIgG and splenectomy following CS were done without platelet transfusion. Splenectomy was performed immediately after CS in all patients, and two of them were hysterectomised (one with HIV infection). After splenectomy, platelet count was normalised in all patients, and they had no haemorrhage, wound haematoma formation or any adverse events. But ITP relapsed in 2/5 patients after 1-2 months. Two newborns had severe thrombocytopenia, which solved spontaneously after 3 days in one or after treatment with IVIgG in other. We propose that splenectomy following cesarean section should be considered as approach for delivery and treatment option for mothers with severe resistant ITP.

Adult↗
PubMed2002

[Surgical treatment of hematologic disorders of the spleen].

Splenectomy--the surgical removal of spleen is being performed in cases of: traumatic spleen rupture, as part of other surgical procedures, number of hematological, infectious and metabolic disorders. During the years 1988.-2001., there were 396 splenectomies performed at the First surgical clinic, for the cause of: autoimmune disorders 187 (47.34%), lymphoproliferative diseases 89 (22.59%). Hodgkin disease 35(8.94%), myeloproliferative disease 39 (9.95%), as part a of "staging" laparotomy 37(9.34%), other hematological disorders 7(2.20%). The spleen of [table: see text] 244 patients weighted 500-1500 g(61.62%), in 56 patients (14.14%) weighted less than 500 g, and in 96 patients (24.24%) spleen weighted more than 1500 g. Patients with thrombocytes less than 40,000/l 16 (4.04%) were perioperativly treated with fresh thrombocytes. Postoperative morbidity and mortality were registered in 54 (13.64%), i.e. 8 (2.02%) patients. Delayed results depended on primary disorder, comorbidities and supportive therapy. In this article, the particularities of the operative procedure were discussed, as well as importance of cooperation of surgeon and hematologist in perioperative treatment.

Adolescent↗
PubMed2002

[Autotransplantation of the spleen].

Auto transplantation of the spleen can be performed in the patients with traumatic rupture of the spleen, in whom spleen could not be conserved in the other way. The right indication for this method is isolated rupture of the spleen (concvasation or complete devascularisation). This method is not recommended in the endangered patients, patients with previous disease of the spleen as well as in the patients with the perforation of the other abdominal organs at the same time. Auto transplantation was performed in 12 patients with isolated splenic rupture and hematoperitoneum, 11 men and one woman. The majority of patients are younger. In 8 patients, autotransplant was placed into big omentum, in three into lipomatous tissue surrounding left kidney, and in one into anterior abdominal wall. In all the patients from this group, following analysis were taken: MCV (middle volume of erythrocytes), HTC, Hb, Le, Glucose, urea, creatinin, sodium, potassium, alkali phosphatasis, target cells, Howell Jolly's bodies, Heinz's bodies, IgG, IgA, IgM, C3, C4, T3, T4, T8, B, segmentated, eosinophiles, lymphocytes, reticulocytes, thrombocytes, fibrinogen, PT, APTT, aggregation of thrombocytes and aggregation of thrombocytes on collagen. The same parameters were taken in 12 patients with surgery similar to splenectomy and in 12 after splenectomy. After splenectomy, there was decrease of the immunologic defending abilities of the organism because of the loss of the childrens function of the spleen, decreased level of the opsonines and tutsin, which leads to the impaired phagocytosis, decreased concentration of IgM and T and B lymphocytes, while in patients after auto transplantation the results were physiological. The most important thing in the assessment of the function of the autotransplanted spleen is scintigraphic investigation using 99mTc-denaturated red blood cells. In our study, auto transplant function was assessed in 10/12 patients by scintigraphy. Five years after surgery, no one patient was proved to have postsplenectomic sepsis.

Female↗
PubMed2001

Effect of earthworm (G-90) extract on formation and lysis of clots originated from venous blood of dogs with cardiopathies and with malignant tumors.

The stability of homeostasis is important to keep a balance between coagulation and fibrinolysis. A disorder of homeostasis leads to different physiological changes and causes different diseases such as cardiopathies and malignant tumors. Cardiopathies is characterized by a hypercoagulation. In the malignant tumors, besides the hypercoagulation due to plasminogen activators (PA) formed inside the tumor, a disorder of homeostasis leads also to acceleration of the fibrinolysis. The variety of internal and external factors in both cases determine the deviation of time for the clots formation, as well as the lyses of blood and fibrin clots. In this study the venous blood as well as the blood and the fibrin clots, derived from healthy dogs, the dogs with cardiopathies and with malignant tumors, were examined for the time of coagulation and fibrinolysis by adding different substances. In these experiments we used a glycolipoprotein extract from earthworm tissue homogenate (G-90) and the proteolytic enzymes P I and P II, isolated from G-90. The efficacy of the tested substances was comparable with the clinically administered anticoagulants. The most significant differences in clotting time among the three tested groups of dogs were obtained by application of the original G-90. The results suggest a possibility that G-90, along with the fibrinolytic enzymes and other biologically active factors, also contains a factor that decelerates the formation of clot in a specific medium, such as the blood from the dogs with malignant tumors.

Animals↗
PubMed2001

Finite element modeling of electromagnetic signal propagation in a phantom arm.

Improving the control of artificial arms remains a considerable challenge. It may be possible to graft remaining peripheral nerves in an amputated limb to spare muscles in or near the residual limb and use these nerve-muscle grafts as additional myoelectric control signals. This would allow simultaneous control of multiple, degrees of freedom (DOF) and could greatly improve the control of artificial limbs. For this technique to be successful, the electromyography (EMG) signals from the nerve-muscle grafts would need to be independent of each other with minimal crosstalk. To study EMG signal propagation and quantify crosstalk, finite element (FE) models were developed in a phantom-arm model. The models were validated with experimental data collected by applying sinusoidal excitations to a phantom-arm model and recording the surface electric potential distribution. There was a very high correlation (r > 0.99) between the FEM data and the experimental data, with the error in signal magnitude generally less than 5%. Simulations were then performed using muscle dielectric properties with static, complex, and full electromagnetic solvers. The results indicate that significant displacement currents can develop (> 50% of total current) and that the fall-off of surface signal power varies with how the signal source is modeled. Index Terms-Control, electromyography (EMG), finite element (FE), modeling, prosthesis.

Arm↗
PubMed2001

[Protective colostomy or ileostomy?] ].

A group of patients is presented, where colorectal or coloanal anastomosis after resection was performed together with concomitant covering colostomy (102) or ileostomy (25), during the period 1985-2000. Covering colostomy was most often performed upon hepatic flexure (82.1%) and upon sigmoid colon (8.9%). The incidence of complications during performing or closure of colostomy was 6.8% with one case (0.8%) of death due to unsuccessful protection of primary anastomosis. The incidence of complications in covering ileostomy was 16%, with 3 (12%) deaths. Authors are analysing the data from literature about indications and technique of covering enterostomies, comparing them with their experience and concerning the choice of appropriate protective procedure. They came to conclusion that the reason for covering procedure has been in many instances reasonable, and that in the question of protection both methods are comparable, but covering ileostomy has potentially more dangerous complications. Therefore as a method of anastomotic protection authors are generally recommending covering colostomy except in technically specific cases.

Anastomosis, Surgical↗
PubMed2001

[10 years' of production and use of human rabies immunoglobulin in Yugoslavia].

Application of the rabies immunoglobuline is a compulsory part of the prophylaxis of rabies in all severe, transdermal lesions caused by rabies infected animals. Sylvatic rabies has spread in the past few years throughout the whole Yugoslavia, and human cases of rabies have also been reported in other East European countries. In order to achieve the highest level of rabies prophylaxis, apart from postinfective rabies vaccination, it is necessary to provide passive immunization using specific antibodies against rabies. After successful immunization of the young, healthy volunteers in 1990, National Blood Transfusion Institute, in cooperation with the Pasteur Institute from Novi Sad, prepared the first quantities of immunized plasma by plasmapheresis procedure and human rabies immunoglobuline. Without national production, sufficient quantities of human rabies immunoglobuline could not be provided, since the price on the world market is rather high (over $1000 per patient).

Antibodies, Viral↗
PubMed2000

Secondary intracranial meningiomas after high-dose cranial irradiation: report of five cases and review of the literature.

PURPOSE: To review cases of secondary intracranial meningiomas following high-dose cranial irradiation (>/= 10 Gy) identified in Slovenia between 1968 and 1998, to determine their histological profile and to review the literature on this topic. METHODS AND MATERIALS: Personal files of patients treated for secondary intracranial meningioma during a 31-year period were reviewed. In cases which met the criteria for radiation-induced tumors, steroid hormone receptor and Ki-67 status were analyzed. For the literature review, computerized database systems and reference lists from respective publications were used. RESULTS: Five patients (2 females, 3 males), 3-11 years old at the time of cranial irradiation, developed secondary meningioma after a latency period of 9.5-31.5 years. Three patients had multiple tumors and 2 developed recurrent disease. Of 9 histologically examined tumors, 5 were graded as benign and 4 as atypical meningiomas, with Ki-67 proliferative index 3.2 +/- 3.6 and 10 +/- 6, respectively. The ratio between positive and negative meningiomas regarding immunostaining for progesterone and estrogen receptors was eight-to-one and six-to-three, respectively. Cumulative actuarial risk of secondary meningioma in a cohort of 445 children 16 years or younger treated with high-dose cranial irradiation between 1968 and 1990 in Slovenia at 10, 20, and 25 years was 0.53%, 1.2%, and 8.18%, respectively. Out of 126 cases of radiation-induced meningiomas reported, 57% were females and 43% were males, with mean age at presentation 33 +/- 17.3 years. The majority (68%) of patients was irradiated during childhood. The latency period was significantly shorter in those who aged 5 years or less at the time of cranial irradiation (p = 0.04), and in those with atypical/anaplastic tumor (p = 0.01). Correlation between radiation dose and latency period could not be found. CONCLUSION: Secondary meningiomas following high-dose cranial irradiation are characterized by younger age at presentation, by higher male-to-female ratio and by biologically more aggressive variants compared to primary spontaneous meningiomas. Latency period correlated with the age at the time of cranial irradiation and with tumor grade but not with irradiation dose. Ki-67 immunoreactivity correlated with histological grade. The progesterone and estrogen receptor immunoreactivity was high. The risk for development of secondary meningioma after high-dose cranial irradiation was increasing with the time of follow-up.

Brain Neoplasms↗
PubMed2000

Pharmacodynamic study of Hypericum perforatum L.

The effects of Hypericum perforatum L. (Hypericaceae) crude ethanol extract (A), ethyl acetate extract (B), aqueous extract (C) and infusion (I), on pentobarbital induced sleeping time, intestinal motility, and their analgesic activity, have been investigated. Extracts A and B exhibited significant stimulatory and antidepressant effects on the CNS. Both extracts prolonged sleep, increasing time up to more than 25 min. The antidepressive activity of extract A was also achieved by significant reduction of the myorelaxant activity of diazepam. Extract B exhibited strong analgesic activity reducing abdominal stretching induced by acetic acid by nearly 50 %. Extracts A, B and C exhibited spasmolytic activity, significantly reducing intestine motility.

Acetic Acid↗
PubMed2000

Role of axon-deprived Schwann cells in perineurial regeneration in the rat sciatic nerve.

The role of Schwann cells (SC) in perineurial regeneration after nerve injury has not yet been resolved. It was hypothesized that SC alone are able to induce at least partial morphological restoration of the destroyed orthotopic perineureum (PN). To test the hypothesis, a permanently denervated segment of the rat sciatic nerve was made acellular by freeze-thawing, except in its most proximal part where non-neuronal cells were left intact. Restoration of the frozen segment by these cells was examined by electron microscopy and immunohistochemistry of the SC marker, S-100 protein, 4 and 8 weeks after injury. The PN regenerated from undifferentiated fibroblast-like cells. In the presence of migrant SC without axons, regenerated cells in the place of the former PN were stacked in several layers and, in accordance with the hypothesis, partially expressed typical features of the perineurial cells (PC): pinocytotic vesicles, short fragments of basal lamina and tight junctions. Migrant SC induced formation of pseudo-minifascicles even in the epineurium. In these, SC organized the adjacent fibroblasts into a multilayered circular sheath, and induced their partial differentiation towards perineurial cells. Further experiments demonstrated that regenerating axons are required for complete morphological differentiation of the regenerated perineurial cells either in the orthotopic PN or in minifascicles.

Animals↗