Biomechanical findings in rats undergoing fascial reconstruction with graft materials suggested as an alternative to polypropylene.

AIMS: Graft materials used for pelvic floor reinforcement should still be considered as investigational and, therefore, evaluated experimentally and within clinical trials. The present report describes our biomechanical findings in rats implanted with selected novel implant materials, which in recent years have been suggested as alternatives to plain polypropylene (PP) meshes. METHODS: Full thickness abdominal wall defects were primarily repaired by the implant of interest. Experiments involved eight different implant materials: two partly degradable synthetic implants, that is, a hybrid of polyglactin 910 with PP (Vypro II) and collagen coated PP (Pelvitex); two non-cross linked (Surgisis, InteXen LP) and two cross-linked materials (Pelvicol, Pelvisoft) and two porous modifications of InteXen LP and Pelvicol implants. At different time points (7, 14, 30, and 90 days), the implants and surrounding host tissue (explant) were harvested and tensiometry was performed. Tensile strength and location of breakage were recorded. RESULTS: In general resorbable non-cross linked collagen matrices and porous materials were weaker after 90 days; similar behavior was seen for implant materials alone and their construction with the surrounding native tissue. Both non-porous and porous modification of InteXen LP appeared at 90 days as a very thin layer of collagen that was two-thirds, respectively one-third of the initial thickness. CONCLUSIONS: In experimental conditions, sufficient strength was obtained only after 3 months, and PP containing constructs appeared as the strongest though reconstruction with Pelvicol showed comparable outcomes. Lower values for strength of non-cross linked and porous collagen materials are questioning their efficacy for pelvic floor reconstruction.

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.

Embryonic stage-related properties of sea urchin embryo chromatin.

Two chromatin components, obtained by buoyant density centrifugation of the unsheared blastula and gastrula chromatin of a sucrose/glucose gradient, have been comparatively characterized. When compared to the heavy fraction the light fraction (i) represents a far smaller part of chromatin, (ii) contains a higher RNA/DNA mass ratio and a higher proportion of newly synthesized nonhistone proteins and (iii) possesses greater template activity for RNA synthesis. Gastrulation of the embryos was found to render the dense chromatin fraction less compact and both chromatin subpopulations more transcriptable and enriched with newly synthesized non-histone proteins.

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.

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.

Hybrid PLtl promoter with dual regulation control.

The newly constructed PLtl hybrid promoter is composed of the operator and promoter sequences of tac and the -35 to -135 region of the phage lambda PL promoter, which contains the AT-rich block and the OL2 and OL3 segments. Transcriptional properties of PLtl were examined and compared with tac and lambda PL as reference promoters. The hybrid PLtl exhibits different and improved properties over tac promoter in four ways: (i) when repressed, the repression is almost complete; (ii) after complete induction, the hybrid PLtl promoter shows a 1.4-2 times higher expression; (iii) the hybrid PLtl promoter permits flexible gene expression because it can be utilized under either or both repression controls simultaneously; (iv) the PLtl promoter permits enhanced expression of genes encoding products with unknown properties. When compared with the strong promoter PL from phage lambda, results with the PLtl promoter in lacZ fusion constructs show higher levels of beta-galactosidase activity. We also constructed a plasmid vector, pPLtl7G, which contains the hybrid PLtl promoter with a polylinker sequence at its 3' end, which facilitates efficient fusions of foreign genes in any of the reading frame.

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.

Third generation aromatase inhibitors may prevent endometrial growth and reverse tamoxifen-induced uterine changes in postmenopausal breast cancer patients.

BACKGROUND: Tamoxifen may induce uterine abnormalities of clinical concern. Our aim was to compare early uterine changes occurring in postmenopausal breast cancer patients treated in first-line with tamoxifen or third generation aromatase inhibitors. We also assessed the effect of aromatase inhibitors on tamoxifen-induced uterine changes. PATIENTS AND METHODS: Seventy-seven consecutive postmenopausal breast cancer patients scheduled to start endocrine treatment were included in this prospective study. Transvaginal ultrasonography (TVUS) was carried out before and after 3 months of therapy. No interventions were done on pre-existing asymptomatic uterine abnormalities seen on baseline sonography. RESULTS: After 3 months of therapy, tamoxifen significantly increased endometrial thickness and uterine volume. Additionally, tamoxifen induced endometrial cysts and polyps, and increased the size of pre-existing fibroids. In contrast, aromatase inhibitors did not stimulate endometrial growth and were not associated with endometrial pathologies seen under tamoxifen. Furthermore, aromatase inhibitors decreased endometrial thickness and uterine volume in patients previously treated with tamoxifen. CONCLUSIONS: Our study demonstrates that tamoxifen induces uterine abnormalities from as early as 3 months of therapy. In contrast, these abnormalities are not seen in patients on aromatase inhibitors. Furthermore, our data indicate that tamoxifen therapy followed by an aromatase inhibitor may lead to a reduction in endometrial pathologies associated with tamoxifen.

["Ex situ" reconstruction of blood vessels of the renal hilus in experimental transplantation in dogs]. / "Ex situ" rekonstrukcija krvnih sudova hilusa bubrega kod eksperimentalne transplantacije na psima.

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.

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.

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.

Lectin activity of chromatin non-histone proteins.

Non-histone proteins from chromatin of sea urchin embryos were found to possess the ability to agglutinate erythrocytes.

[Intensive radiotherapy and polychemotherapy, clinical stage and systemic manifestations of the disease as parameters important in the prognosis for Hodgkin's disease]. / Intenzivna radioterapija i polikemoterapija, klinicki stadij i sistemske manifestacije bolesti kao parametri znacajni za prognozu Hodgkinove bolesti.

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).

DNA region responsible for transcriptional regulation of the Escherichia coli penicillin amidase (pac) gene by CRP and PAA.

Transcriptional regulation of Escherichia coli ATCC11105 penicillin amidase gene (pac) by cAMP receptor protein (CRP) and phenylacetic acid (PAA) was studied by using operon fusions with divergent reporter gene (lacZ, and phoA) constructs. A 150 bp DNA segment essential for the regulation of pac gene transcription by CRP and PAA was defined.

Characterization of two rat globin cDNA clones.

The rat globin gene system is suitable for studying a coordinated regulation of seven genes from two gene families. A rat reticulocyte cDNA globin library has been constructed and two clones analyzed in detail. pBRrg 5 contains alpha while pBRrg X contains beta type sequence. These cloned cDNAs will be useful probes of structure and function of rat globin genes. The deduced amino acid sequences extend the information about the variability of rat globin chains.