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Biomedical subjects

M Konstantinović

Publications and source records attributed to M Konstantinović.

At least 19 recordsLinked to original sources
PubMed2001

DNA architecture and transcriptional regulation of the Escherichia coli penicillin amidase (pac) gene.

The transcriptional regulation of Escherichia coli ATCC11105 penicillin amidase (pac) gene was studied by modifying DNA sequences responsible for promoter activation by cyclic AMP receptor protein (CRP). The nucleotide sequence of the 5'-flanking region of the pac gene contains putative tandem CRP binding sites positioned at -69/-70 and at -111/-112 with respect to the transcriptional start site. Our results obtained with either point mutations or insertion or deletion mutants (each of which rotated the helix structure at the CRP binding site one-half turn) showed significant decrease of penicillin amidase (PA) activity, suggesting the CRP as a major activator. In this study, the evidence for the importance of spacing between tandem binding sites for CRP as well as for their location related to the promoter core sequence has been provided. Involvement of integration host factor (IHF) as an additional regulatory protein in the pac gene transcription regulation was also analyzed. It is shown that activation of the pac gene transcription is elevated by IHF.

Base Sequence↗
PubMed1994

The penicillin amidase of Arthrobacter viscosus (ATCC 15294).

The nucleotide (nt) sequence of the gene encoding penicillin G amidase (PA) of Arthrobacter viscosus strain ATCC 15,294 was determined. The sequence contained an open reading frame of 2406 nt with a G+C content of 37%. The deduced amino-acid sequence shows significant homology with other so far identified beta-lactam amidases of Gram- bacteria.

Amino Acid Sequence↗
PubMed1992

The primary structure of Providencia rettgeri penicillin G amidase gene and its relationship to other gram negative amidases.

The nucleotide sequence of Penicillin G amidase (PA,E.C.3.5.1.11) of Providencia rettgeri was determined. We aligned our P. rettgeri PA with other known Gram negative periplasmically located beta-lactam amidases. The analysis revealed a high homology with other Enterobacteric amidases (60%-65%), while with similar Pseudomonas sp. amidases the homology exceeded 25%. These homologies indicate their common ancestry.

Amino Acid Sequence↗
PubMed1991

Curved DNA without AA/TT dinucleotide step.

The evidence is accumulating that dinucleotide steps other than AA/TT affect DNA flexure of AnTm (m + n greater than = 4) containing fragments. However, it is not clear whether macroscopic DNA flexure without AA/TT steps might occur. In this paper we demonstrate the anomaly in electrophoretic mobility of non AA/TT repetitive DNA sequences which is a function of sequence phasing. Therefore, our results show that PyPu (TA) and AG/CT steps, angulary separated by close to 180 degrees from Pu/Py (GC) and GG/CC steps, bend DNA, even in the absence of AnTm tracts.

Adenine Nucleotides↗
PubMed1990

[Partial heterotopic and total orthotopic transplantation of the liver in dogs].

From 1983 to 1988 on the Department for Experimental Surgery 20 preservations of the liver has been done, with ice cold Euro- Collins and Ringer solutions, either with in situ or with on banch technique after fast expantation. On five dogs standard 55% left hepatectomy has been done and the right side preserved in situ. Partial heterotopic liver transplantation to the right iliac fossa was performed on five dogs. Total vascular exclusion of the liver and extracorporal inierior vena cava and jugular vein by pass with assisted circulation was performed on one dog, without assistance on four dogs. Total orthotopic liver transplantation was performed on two dogs. The surgical team practiced the technique of liver transplantation in experiment and liver resection with in situ technique and on banch technique.

Animals↗
PubMed1990

["Ex situ" reconstruction of blood vessels of the renal hilus in experimental transplantation in dogs].

The variations of arterial and venous hillar blood vessels in human kidneys are numerous and surgical transplant teams have to know them. It is very important during doner-nephrectomy for transplantation. Sometimes, after doner, nephrectomy and kidney cold perfusion with Collins, there is a need for vascular repair of kidney hillar blood vessels, using microvascular surgical technique. The aim of this repair is: to have a kidney with main renal artery of good length and size and with main renal vein of good length and size. This procedure is called: extracorporeal "ex-situ" vascular repair of kidney hillar blood vessels. In the period 1987-1988, in our Experimental Surgery Unit a total of 20 dogs were operated on (kidney autotransplantation) and only in four (4) dogs we found variations in numbers of kidneys arterial and venous hillar blood vessels (20%) and repaired those vessels after cold perfusion of kidney. One dog had kidney with double renal arteries and double renal veins, and we had to make fusion the both arteries into the main renal artery of good size (5 mm) and the both veins into the renal vein of good size (12 mm). Three dogs had kidneys with main trunk of renal artery and one important separate polar renal artery, and we had to make implantation of separate polar renal artery into the main trunk of renal artery (end-te-side vascular anastomosis). For those vascular reconstructions we used polipropilene 6-o or -o as suturae material and binocular (magnification 2.5 x). The hemodynamically results of those reconstructions immediately after kidney implantation were very satisfactory.

Animals↗
PubMed1990

[Intensive radiotherapy and polychemotherapy, clinical stage and systemic manifestations of the disease as parameters important in the prognosis for Hodgkin's disease].

In the period from 1961 to 1982, 82 patients (36 females and 46 males) with Hodgkin's disease were treated. The median age was 40 years. According to the way of treatment, the patients were divided into two groups, the first group with 30 patients treated by local x-rays and/or monochemotherapy (treated up to 1971) and the second group with 52 patients treated by aggressive tele-cobalt therapy and/or MOPP polychemotherapy (after 1972). In the first group of patients, complete remission was achieved in 9 cases, partial remission in 15, while there was no remission in 6 cases. In the second group, complete remission was achieved in 40 cases, partial remission in 9, while no remission could be achieved in 3 cases. The difference in the number of remissions achieved between the patients treated up to 1971 and patients treated later is statistically significant (chi 2 = 15.52 p less than 0.0001). The median age was significantly higher in the group of patients treated by aggressive therapy (65:12 months). Seven patients from the first group survived for more than 5 years, 5 being still alive. In the second groups 29 patients survived for more than 5 years, 24 of them being still alive. The difference in survival between these two groups is significant (chi 2 = 11.37; p less than 0.001). There is a significant difference in surviving between patients in different stages of the disease (chi 2 = 27.47; p less than 0.00001). Between the patients without general symptoms (A) and the patients with systemic manifestations (B) the difference in numbers of remissions is statistically significant (chi 2 = 8.44; p less than 0.005). The difference in survival between these two groups of patients is also significant (chi 2 = 16.52; p less than 0.0001).

Adult↗
PubMed1983

Nuclear matrix from resting and concanavalin A-stimulated human lymphocytes.

Concanavalin A-induced transformation and proliferation of human peripheral blood lymphocytes was found to be accompanied by morphological and biochemical changes of the nuclear matrix. Nuclear matrix spheres increased in size as well as in protein and RNA content. Experimental data suggesting the involvement of the nuclear matrix in DNA replication processes are also presented.

Cell Nucleus↗
PubMed1982

Comparative studies of rat liver and sea urchin embryo nuclear matrices: partial fractionation and protein kinase activity distribution.

Rat liver and sea urchin embryo nuclear matrices were found to differ in composition and in the strength of the association of their structural elements. Apart from the qualitative differences in composition, the embryonic matrices retained greater amounts of nuclear proteins and DNA, and were less susceptible to ultrasonic treatment than those of rat liver. They were essentially resistant to mild sonication, by which the rat liver matrix structure was resolved into two distinct fractions, referred to by Berezney (1980) as matricin and ribonucleoprotein (RNP). Both sub-fractions exhibited a protein kinase activity; the phosphorylating capacity of the RNP-associated protein kinases was found to be higher than that of the matricin-bound enzyme. The preferred substrate was among the secondary matrix proteins. In sea urchin embryos, sonication introduced no change in the type and lesion of the matrix proteins phosphorylated by the associated enzyme.

Animals↗