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Dive into the research topics where Ivan Donev is active.

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Featured researches published by Ivan Donev.


BioScience Trends | 2015

Serum expression levels of miR-17, miR-21, and miR-92 as potential biomarkers for recurrence after adjuvant chemotherapy in colon cancer patients

Nikolay Conev; Ivan Donev; Assia Konsoulova-Kirova; Trifon Chervenkov; Javor K. Kashlov; Krasimir Ivanov

The present study examined whether miR-17, miR-21, miR-29a, and miR-92 that are dysregulated in colon cancer (CC) can serve as potential predictive markers for relapse of disease after radical surgery and adjuvant chemotherapy. Real-time reverse transcription quantitative polymerase chain reaction was used to measure the expression levels of the miRNAs in serum samples from 37 patients with CC and 7 healthy individuals, tested as a control group. The area under the receiver operating characteristic curve (AUC) was then used to evaluate the predictive performance of the four miRNAs alone or in combination and compare it with carcinoembryonic antigen. The expression of miR-17, miR-21 and miR-92 were significantly higher in serum of patients with disease relapse. The AUCs for miR-17, miR-21, miR-92 for Nx patients were 0.844, 0.948, and 0.935, respectively (p < 0.05). Combining the four miRNAs for stage III patients increased the diagnostic performance, yielding an AUC of 0.881, with a sensitivity of 83.3% and a specificity of 85.7% (p < 0.05). Our study suggests that the expression levels of serum miR-21, miR-17, and miR-92 in patients with CC who underwent radical surgery and adjuvant chemotherapy may have diagnostic value for differentiating between recurred and non-recurred patients.


BioScience Trends | 2016

Serum levels of RIPK3 and troponin I as potential biomarkers for predicting impaired left ventricular function in patients with myocardial infarction with ST segment elevation and normal troponin I levels prior percutaneous coronary intervention

Javor K. Kashlov; Ivan Donev; Jordanka G Doneva; Veselin Dobrev Valkov; Arpine Kirkorova; Peter I. Ghenev; Nikolay Conev; Temenuzhka Radeva; Borislav Ivanov; Zhaneta Georgieva

The current study examined the serum levels of receptor-interacting protein kinase 3 (RIPK3) in 51 patients with New York Heart Association (NYHA) class III-IV heart failure, 53 patients with myocardial infarction with ST elevation (STEMI), and 19 healthy subjects serving as a control group. An enzyme-linked immunoadsorbent assay (ELISA) was used to measure the levels of RIPK3 expression in serum. The area under the receiver operating characteristic curve (AUC) was then used to evaluate the predictive performance of RIPK3 and troponin I in patients with STEMI. In patients with normal levels of troponin I prior to percutaneous coronary intervention (PCI), serum levels of RIPK3 and troponin I after PCI were sufficient to differentiate patients with a preserved left ventricular ejection fraction (LVEF) from those with impaired left ventricular function after PCI (AUC = 0.780 (95% CI: 0.565-0.995, p = 0.043) with a sensitivity of 76.9% and a specificity of 71.4% vs. AUC = 0.735 (95% CI: 0.530-0.941, p = 0.038) with a sensitivity of 88.2% and a specificity of 63.6% at the optimal cutoff values, respectively). Moreover, elevated levels of troponin I after PCI were associated with an increased risk of an LVEF < 50% prior to discharge (odds ratio, 1.014; 95 % CI, 1.001 to 1.027; p = 0.03), while elevated levels of RIPK3 were not associated with such a risk. The current findings suggest that in patients with normal levels of troponin I prior to PCI, serum levels of RIPK3 and troponin I can serve as a potential marker to identify patients with a decreased LVEF, thus possibly allowing an early shift to more intensive therapy.


Cureus | 2018

Quantitative Analysis of Tumor-associated Tissue Eosinophilia in Recurring Bladder Cancer

Hristo Popov; Ivan Donev; Peter I. Ghenev

The relatively high incidence of recurrence of bladder cancer is a serious problem in clinical practice. At present, there are no objective microscopic criteria for evaluation of the tendency for local relapse. Besides the phenotypic properties of the tumor parenchymal cells, possible signs in regard to recurrence could also be derived from the peculiarities of the tumor stroma. The stromal reaction, manifested by inflammatory infiltration in the tumor is considered to influence the biological behavior of tumors. Also, a relationship has been reported between the number of eosinophils and the survival of patients. The aim of the present study is to analyze tumor-associated tissue eosinophilia (TATE) and to compare TATE density in the initial foci of age and gender-matched 156 cases of recurrent and non-recurrent bladder cancers; the tumors that have relapsed within six months after removal and contained statistically significant greater numbers of eosinophils in primary cancer sites. These results suggest that TATE may be one of the probable prognostic signs for local relapse of urothelial cancer.


World Journal of Gastrointestinal Surgery | 2017

International scientific communications in the field of colorectal tumour markers

Krasimir Ivanov; Ivan Donev

AIM To analyze scientometrically the dynamic science internationalization on colorectal tumour markers as reflected in five information portals and to outline the significant journals, scientists and institutions. METHODS A retrospective problem-oriented search was performed in Web of Science Core Collection (WoS), MEDLINE, BIOSIS Citation Index (BIOSIS) and Scopus for 1986-2015 as well as in Dervent Innovations Index (Derwent) for 1995-2015. Several specific scientometric parameters of the publication output and citation activity were comparatively analyzed. The following scientometric parameters were analyzed: (1) annual dynamics of publications; (2) scientific institutions; (3) journals; (4) authors; (5) scientific forums; (6) patents - number of patents, names and countries of inventors, and (7) citations (number of citations to publications by single authors received in WoS, BIOSIS Citation Index and Scopus). RESULTS There is a trend towards increasing publication output on colorectal tumour markers worldwide along with high citation rates. Authors from 70 countries have published their research results in journals and conference proceedings in 21 languages. There is considerable country stratification similar to that in most systematic investigations. The information provided to end users and scientometricians varies between these data-bases in terms of most parameters due to different journal coverage, indexing systems and editorial policy. The lists of the so-called “core” journals and most productive authors in WoS, BIOSIS, MEDLINE and Scopus along with the list of the most productive authors - inventors in Derwent present a particular interest to the beginners in the field, the institutional and national science managers and the journal editorial board members. The role of the purposeful assessment of scientific forums and patents is emphasized. CONCLUSION Our results along with this problem-oriented collection containing the researchers’ names, addresses and publications could contribute to a more effective international collaboration of the coloproctologists from smaller countries and thus improve their visibility on the world information market.


Intractable & Rare Diseases Research | 2017

Rare case of ameloblastoma with pulmonary metastases

Ivan Valkadinov; Nikolay Conev; Dian Dzhenkov; Ivan Donev

Ameloblastoma is a rare low-grade odontogenic tumor of epithelial origin. The World Health Organization (WHO) has defined malignant ameloblastoma (MA) as a histologically benign-appearing ameloblastoma that has metastasized. Treatment of the primary ameloblastoma usually consists of radical excision of the tumor and adjuvant radiotherapy. Chemotherapy should be used to treat metastases due to its indolent clinical course. Presented here is the case of a 43-year-old woman who was admitted to a hospital in 2006 with a large mass involving the neck and left mandible. The mass had formed over years and had been neglected. The woman was diagnosed with a primary ameloblastoma of the mandible. Surgical resection was performed, followed by adjuvant radiotherapy. In September 2016, she was admitted again, and the findings were consistent with metastases of the previously identified ameloblastoma to the lungs. The patient was evaluated for further chemotherapy with 6 cycles of cisplatin at a dose of 100 mg/m2 on day 1, 5-FU at a dose of 1000 mg/m2/day on day 1-4 (3 wk), and pegylated filgrastim. The current case represents the classical course of a rare disease, which in this instance involved the common presentation of MA. This case is a valid incidence of MA based on the typical histology, findings from a lung biopsy, the immunohistochemical profile of the tumor, the typical clinical features, and a history of a previous primary disease.


BioScience Trends | 2017

Role of the pretreatment (18)F-fluorodeoxyglucose positron emission tomography maximal standardized uptake value in predicting outcomes of colon liver metastases and that value's association with Beclin-1 expression.

Eleonora Dimitrova; Borislav Chaushev; Nikolay Conev; Javor K. Kashlov; Aleksandar Zlatarov; Dilyan Petrov; Hristo B. Popov; Nadezhda T. Stefanova; Kameliya Bratoeva; Ivan Donev

The current study sought to evaluate the predictive and prognostic performance of the maximum standardized uptake value (SUVmax) prior to treatment in 43 patients with colon cancer and unresectable liver metastases. Patients with colon cancer who underwent 18F-FDG-PET/computed tomography (CT) scans for staging before the start of first-line 5-fluorouracil-based chemotherapy were retrospectively analyzed. Expression of Beclin-1 in cancer cells was evaluated in primary tumors using immunohistochemical staining. The pretreatment SUVmax for liver metastases was not able to predict progression-free survival but was significantly associated with poorer overall survival, with a hazard ratio of 2.05 (95 % CI, 1.016-4.155). Moreover, a negative correlation was noted between SUVmax and expression of a marker of autophagy - Beclin-1 (rho = -0.42, p = 0.006). This suggests that the pretreatment SUVmax in 18F-FDG PET/CT is a useful tool to help predict survival outcome in patients with colon cancer and unresectable liver metastases and may significantly distinguish between patients with low and high levels of Beclin-1 expression (AUC = 0.809, 95% CI: 0.670-0.948, p = 0.001).


Archive | 2016

Adjuvant Treatment in Colon Cancer

Ivan Donev; Nikola Kolev; Valentin Ignatov; Aleksandar Zlatarov Anton Tonev; Assia Konsoulova; Elitza Entcheva; Plamena Drenakova; Krasimir Ivanov

Worldwide, more than 1 million people develop colorectal cancer (CRC) annually. CRC is a major health problem in the Western world and the second most common cause of cancer mortality. To improve performance, the role of chemotherapy for CRC has increased dramatically over the last decade. The vast majority of CRC patients now receive chemotherapy with multiple agents that are currently approved for the treatment in the appropriate setting [1]. However, it is a complex process to select the optimal chemotherapy for each patient and practice evidence gap is still a problem. Some guidelines for the treatment of CRC have been developed to promote the standardization of CRC treatment. Postoperative, or “adjuvant,” systemic therapy has become standard for stage III colon cancer. Adjuvant therapy should also be strongly considered in stage II patients. It is generally recommended for any medically fit patient with stage II cancer with unfavorable factors. The hypothesis that the antitumor activity of the combination agent, including oxaliplatin, irinotecan, bevacizumab, cetuximab in metastatic cure rates, would result in increased adjuvant proved to be often wrong. Although new drug development takes years, targeted drug use can occur more quickly with advanced tests and will be a focus of future work. In addition, efforts will focus on identifying biomarkers that predict response to systemic therapy so that tailored therapy can be initiated. The future of oncology will come with the better understand‐ ing of the biology and genetics of the tumor and its host. This will help to develop tailored approach to the patients, including more specific systemic therapy, aimed at molecular targets of the malignant tumor, thus reducing the negative effects. At that time, the treatment of oncological diseases will experience a new era, comparable to the introduction of antibiotics.


Supportive Care in Cancer | 2018

One-minute time interval estimation as a novel ultrashort tool for distress screening

Nikolay Conev; Ivan Donev; Dragomir Svetozarov Stoyanov


Journal of Clinical Oncology | 2018

Time perception as a novel ultra-short screening tool for distress in cancer patients.

Nikolay Conev; Ivan Donev; Dragomir Svetozarov Stoyanov; Martina Ivanova; Eleonora Dimitrova; Asen Yanchev


Journal of Mind and Medical Sciences | 2017

Protective Role of S-Adenosylmethionine Against Fructose-Induced Oxidative Damage in Obesity

Kameliya Bratoeva; Mariya Radanova; Albena Merdzhanova; Ivan Donev

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Nikolay Conev

Medical University of Varna

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Eleonora Dimitrova

Medical University of Varna

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Javor K. Kashlov

Medical University of Varna

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Assia Konsoulova

Medical University of Varna

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Kameliya Bratoeva

Medical University of Varna

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Krasimir Ivanov

Medical University of Varna

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Arpine Kirkorova

Medical University of Varna

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Borislav Ivanov

Medical University of Varna

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Dimitar Kalev

Medical University of Varna

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