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81.
Functional connectivity in islets of Langerhans from mouse pancreas tissue slices
Jurij Dolenšek, Matjaž Perc, Marko Marhl, Marjan Rupnik, Dean Korošak, Andraž Stožer, Marko Gosak, 2013, izvirni znanstveni članek

Opis: We propose a network representation of electrically coupled beta cells in islets of Langerhans. Beta cells are functionally connected on the basis of correlations between calcium dynamics of individual cells, obtained by means of confocal laser-scanning calcium imaging in islets from acute mouse pancreastissue slices. Obtained functional networks are analyzed in the light of known structural and physiological properties of islets. Focusing on the temporal evolution of the network under stimulation with glucose, we show thatthe dynamics are more correlated under stimulation than under non-stimulated conditions and that the highest overall correlation, largely independent of Euclidean distances between cells, is observed in the activation and deactivation phases when cells are driven by the external stimulus. Moreover, we find that the range of interactions in networks during activity shows a clear dependence on the Euclidean distance, lending support to previous observations that beta cells are synchronized via calcium waves spreading throughout islets. Most interestingly, the functional connectivity patterns between beta cells exhibit small-world properties, suggesting that beta cells do not form a homogeneous geometric network but are connected in a functionally more efficient way. Presented results provide support for the existing knowledge of beta cell physiology from a network perspective and shedimportant new light on the functional organization of beta cell syncitia whose structural topology is probably not as trivial as believed so far.
Ključne besede: islets of Langerhans, mouse pancreas
Objavljeno: 16.06.2017; Ogledov: 131; Prenosov: 1
.pdf Polno besedilo (798,57 KB)

82.
Intracellular serotonin modulates insulin secretion from pancreatic ß-cells by protein serotonylation
Nils Paulmann, Maik Grohmann, Jörg-Peter Voigt, Bettina Bert, Jakob Vowinckel, Michael Bader, Maša Skelin, Marko Jevšek, Heidrun Fink, Marjan Rupnik, Diego Walther, 2009, izvirni znanstveni članek

Opis: While serotonin (5-HT) co-localization with insulin in granules of pancreatic ß-cells was demonstrated more than three decades ago, its physiological role in the etiology of diabetes is stili unclear. We combined biochemical and electrophysiological analyses of mice selectively deficient in peripheral tryptophan hydroxylase (Tph1-/-) and 5-HT to show that intracellular 5-HT regulates insulin secretion. We found that these mice are diabetic and have an impaired insulin secretion due to the lack of 5-HT in the pancreas. The pharmacological restoration of peripheral 5-HT levels rescued the impaired insulin secretion in vivo. These findings were further evidenced by patch clamp experiments with isolated Tph1-/- ß-cells, which clearly showed that the secretory defect is downstream of Ca2+ -signaling and can be rescued by direct intracellular application of 5-HT via the clamp pipette. In elucidating the underlying mechanism further, we demonstrate the covalent coupling of 5-HT by transglutaminases during insulin exocytosis to two key players in insulin secretion, the small GTPases Rab3a and Rab27a. This renders them constitutively active in a receptor-independent signaling mechanism we have recently termed serotonylation. Concordantly, an inhibition of such activating serotonylation in ß-cells abates insulin secretion. We also observed inactivation of serotonylated Rab3a by enhanced proteasomal degradation, which is in line with the inactivation of other serotonylated GTPases. Our results demonstrate that 5-HT regulates insulin secretion by serotonylation of GTPases within pancreatic ß-cells and suggest that intracellular 5-HT functions in various microenvironments via this mechanism in concert with the known receptor-mediated signaling.
Ključne besede: insulin secretion, serotonin, insulin, glucose, diabetes mellitus, guanosine triphosphatase, exocytosis, pancreas
Objavljeno: 16.06.2017; Ogledov: 95; Prenosov: 0
.pdf Polno besedilo (774,75 KB)

83.
Percutaneous trigeminal ganglion balloon compression rhizotomy: experience in 27 patients
Tadej Strojnik, Tomaž Šmigoc, 2012, izvirni znanstveni članek

Opis: Purpose. Percutaneous ganglion balloon compression (PBC) is a minimally invasive procedure for treatment of trigeminal neuralgia. Materials and Methods. Twenty-seven (19 female and 8 male) patients, who presented with classical symptoms of trigeminal neuralgia, were included. Age ranged from34 to 91 years (median 62 years), 33 procedures were performed. Duration of the symptoms ranged from 1 year to 30 years (median 5 years). Results. After the procedure, pain relief was reported in 25 (93%) patients. In two patients, the pain remained the same. The pain free period ranged from 2 to 74 months (median 15 months). A mean duration of analgesia was longer in patients with ideal pear shape of balloon at the time of the procedure compared to nonideal shape (P = 0.01). No major complications occurred in our group of patients. Conclusions. Percutaneous trigeminal ganglion balloon compression is a safe, simple, and effective method for temporary pain relief in a selective group of trigeminal neuralgia patients.
Ključne besede: balloon compression
Objavljeno: 15.06.2017; Ogledov: 41; Prenosov: 0
.pdf Polno besedilo (2,62 MB)

84.
L-arginine intake effect on adenin nucleotide metabolism in rat parenchymal and reproductive tissues
Gordana Kocić, J. Nikolić, Tatjana Jevtović, Dušan Sokolović, H. Kocić, T. Cvetković, Miloš Pavlović, Avrelija Cencič, D. Stojanovic, 2012, izvirni znanstveni članek

Opis: L-arginine is conditionally essential amino acid, required for normal cell growth, protein synthesis, ammonia detoxification, tissue growth and general performance, proposed in the treatment of men sterility and prevention of male impotence. The aim of the present paper was to estimate the activity of the enzymes of adenine nucleotide metabolismČ 5' -nucleotidase ( 5'-NU), adenosine deaminase (ADA), AMP deaminase, and xanthine oxidase (XO), during dietary intake of L-arginine for a period of four weeks of male Wistar rats. Adenosine concentration in tissues is maintained by the relative activities of the adenosine-producing enzyme, 5' -NU and the adenosine-degrading enzyme-ADA adenosine deaminase. Dietary L-arginine intake directed adenine nucleotide metabolism in liver, kidney, and testis tissue toward the activation of adenosine production, by increased 5' -NU activity and decreased ADA activity. Stimulation of adenosine accumulation could be of importance in mediating arginine antiatherosclerotic, vasoactive, immunomodulatory, and antioxidant effects. Assuming that the XO activity reflects the rate of purine catabolism in the cell, while the activity of AMP deaminase is of importance in ATP regeneration, reduced activity of XO, together with the increased AMP-deaminase activity, may suggest that adenine nucleotides are presumably directed to the ATP regenerating process during dietary L-arginine intake.
Ključne besede: biochemistry
Objavljeno: 15.06.2017; Ogledov: 39; Prenosov: 1
.pdf Polno besedilo (1,16 MB)

85.
Skin cancer and its treatment
Kristjan Orthaber, Matevž Pristovnik, Kristijan Skok, Barbara Perić, Uroš Maver, 2017, pregledni znanstveni članek

Opis: The life expectancy in the Western world is increasing for a long time, which is the courtesy of a higher life standard, a more thorough hygiene, and, of course, the progress of modern medicine. Nevertheless, one of the illnesses that still proves to be a great challenge regardless of the recent advancements in medicine is cancer. Skin cancer is, according to theWorld Health Organization, the most common malignancy for the white population.The beginning of the paper offers a brief overview of the latest available information concerning epidemiology, aetiology, diagnostics, and treatment options for skin cancer, whereas the rest of the article deals with modern approaches to skin cancer treatment, highlighting recent development of nanotechnology based treatment approaches. Among these, we focus especially on the newest nanotechnological approaches combined with chemotherapy, a field which specialises in target specificity, drug release control, and real time monitoring with the goal being to diminish unwanted side effects and their severity, achieving a cheaper treatment and a generally more efficient chemotherapy. The field of nanotechnology is a rapidly developing one, judging by already approved clinical studies or by new theranostic agents that combine both the therapeutic and diagnostic modalities.
Ključne besede: skin cancer, treatment, nanotechnology, nanotechnological methods
Objavljeno: 14.06.2017; Ogledov: 71; Prenosov: 4
.pdf Polno besedilo (1,56 MB)

86.
Age-related differences in percentages of regulatory and effector T lymphocytes and their subsets in healthy individuals and characteristic STAT1/STAT5 signalling response in helper T lymphocytes
Marija Holcar, Aleš Goropevšek, Alojz Ihan, Tadej Avčin, 2015, izvirni znanstveni članek

Opis: The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.
Ključne besede: T lymphocytes, age-related differences, immune system
Objavljeno: 14.06.2017; Ogledov: 64; Prenosov: 2
.pdf Polno besedilo (2,39 MB)

87.
Intermittent chemotherapy and erlotinib for nonsmokers or light smokers with advanced adenocarcinoma of the lung
Matjaž Zwitter, Mirjana Rajer, Viljem Kovač, Izidor Kern, Martina Vrankar, Uroš Smrdel, 2011, izvirni znanstveni članek

Opis: Background. Intermittent application of chemotherapy and tyrosine kinase inhibitors may avoid antagonism between the two classes of drugs. This hypothesis was tested in a Phase II clinical trial. Patients and Methods. Eligible patients were nonsmokers or light smokers, chemo-naïve, with metastatic adenocarcinoma of the lung. Treatment: 4 to 6 cycles of gemcitabine 1250 mg/m2 on days 1 and 4, cisplatin 75 mg/m2 on day 2, and erlotnib 150 mg daily on days 5–15, followed by erlotinib as maintenance. Results. 24 patients entered the trial. Four pts had grade 3 toxicity. Complete remission (CR) and partial remission (PR) were seen in 5 pts and 9 pts, respectively (response rate 58%). Median time to progression (TTP) was 13.4 months and median overall survival (OS) was 23 months. When compared to patients with negative or unknown status of EGFR mutations, 8 patients with EGFR gene activating mutations had significantly superior experience: 4 CR and 4 PR, with median TTP 21.5 months and OS 24.2 months (P < .05). Conclusions. Intermittent schedule with gemcitabine, cisplatin and erlotinib has mild toxicity. For patients who are positive for EGFR gene activating mutations, this treatment offers excellent response rate, time to progression and survival.
Ključne besede: smokers, nonsmokers, cancer treatment, lung cancer, chemotherapy, erlotinib
Objavljeno: 14.06.2017; Ogledov: 70; Prenosov: 2
.pdf Polno besedilo (2,30 MB)

88.
Single nucleotide polymorphisms as prognostic and predictive factors of adjuvant chemotherapy in colorectal cancer of stages I and II
Matej Horvat, Uroš Potočnik, Katja Repnik, Rajko Kavalar, Borut Štabuc, 2016, pregledni znanstveni članek

Opis: Colorectal cancer (CRC) is a highly heterogeneous disease regarding the stage at time of diagnosis and there is special attention regarding adjuvant chemotherapy in unselected patients with stage I and stage II. The clinicohistologically based TNM staging system with emphasis on histological evaluation of primary tumor and resected regional lymph nodes remains the standard of staging, but it has restricted sensitivity resulting in false downward stage migration. Molecular characteristics might predispose tumors to a worse prognosis and identification of those enables identifying patients with high risk of disease recurrence. Suitable predictive markers also enable choosing the most appropriate therapy. The current challenge facing adjuvant chemotherapy in stages I and II CRC is choosing patients with the highest risk of disease recurrence who are going to derive most benefit without facing unnecessary adverse effects. Single nucleotide polymorphisms (SNPs) are one of the potential molecular markers that might help us identify patients with unfavorable prognostic factors regarding disease initiation and recurrence and could determine selection of an appropriate chemotherapy regimen in the adjuvant and metastatic setting. In this paper, we discuss SNPs of genes involved in the multistep processes of cancerogenesis, metastasis, and the metabolism of chemotherapy that might prove clinically significant.
Ključne besede: single nucleotide polymorphism, colorectal cancer, adjuvant chemotherapy
Objavljeno: 14.06.2017; Ogledov: 40; Prenosov: 2
.pdf Polno besedilo (1,27 MB)

89.
Hepatic encephalopathy after transjugular intrahepatic portosystemic shunt in patients with recurrent variceal hemorrhage
Peter Popović, Andrej Zore, Katarina Šurlan Popović, Manca Garbajs, Pavel Skok, 2013, izvirni znanstveni članek

Opis: Purpose.The purpose of this study was to determine the incidence and predictors of hepatic encephalopathy (HE) after transjugular intrahepatic portosystemic shunt (TIPS) and endoscopic therapy (ET) in the elective treatment of recurrent variceal hemorrhage. Methods. Seventy patients were treated with elective TIPS and fifty-six patients with ET. Median observation time was 46.28 months in the TIPS group and 42.31 months in the ET group. Results. 30 patients (42.8%) developed clinically evident portosystemic encephalopathy in TIPS group and 20 patients (35.6%) in ET group. The difference between the groups was not statistically significant (P=0.542; X2 test). The incidence of new or worsening portosystemic encephalopathy was 24.3% in TIPS group and 10.7% in ET group. Multivariate analysis showed that ET treatment (P=0.031), age of >65 years (P=0.022), pre-existing HE (P=0.045), and Childs class C (P=0.051) values were independent predictors for the occurrence of HE. Conclusions. Procedure related HE is a complication in a minority of patients treated with TIPS or ET. Patients with increased age, preexisting HE, and higher Child-Pugh score should be carefully observed after TIPS procedure because the risk of post-TIPS HE in these patients is higher.
Ključne besede: veins, dilated veins, rebleeding, portacaval encephalopathy, liver, cirrhosis, portal hypertension, transjugular intrahepatic portosystemic shunt
Objavljeno: 14.06.2017; Ogledov: 69; Prenosov: 3
.pdf Polno besedilo (1,18 MB)

90.
Quantitative evaluation of growth plates around the knees of adolescent soccer players by diffusion-weighted magnetic resonance imaging
Zmago Krajnc, Mitja Rupreht, Matej Drobnič, 2015, izvirni znanstveni članek

Opis: Purpose. To quantitatively evaluate growth plates around the knees in adolescent soccer players utilizing the diffusion-weighted MR imaging (DWI). Methods. The knees and adjacent growth plates of eleven 14-year-old male soccer players were evaluated by MRI before (end of season´s summer break) and after two months of intense soccer training. MRI evaluation was conducted in coronal plane by PD-FSE and DWI. All images were screened for any major pathological changes. Later, central growth plate surface area (CGPSA) was measured and the apparent diffusion coefficient (ADC) values were calculated in two most central coronal slices divided into four regions: distal femur medial (DFM), distal femur lateral (DFL), proximal tibia medial (PTM), and proximal tibia lateral (PTL). Results. No gross pathology was diagnosed on MRI. CGPSA was not significantly reduced: DFM 278 versus 272, DFL 265 versus 261, PTM 193 versus 192, and PTL 214 versus 210. ADC decrease was statistically significant only for PTM: DFM 1.27 versus 1.22, DFL 1.37 versus 1.34, PTM 1.13 versus 1.03 (p=0.003), and PTL 1.28 versus 1.22. Conclusions. DWI measurements indicate increased cellularity in growth plates around knees in footballers most prominent in PTM after intense training. No detectable differences on a standard PD-FSE sequence were observed.
Ključne besede: soccer, adolescent, quantitative magnetic resonance, knee
Objavljeno: 14.06.2017; Ogledov: 42; Prenosov: 3
.pdf Polno besedilo (1,92 MB)

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