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Biomedical subjects

V Enchev

Publications and source records attributed to V Enchev.

14 recordsLinked to original sources
PubMed2004

Study on the role of 5-fluorouracil in the polymerization of butylcyanoacrylate during the formation of nanoparticles.

The possible involvement of 5-fluorouracil (5FU) in the initiation process of the polymerization of n-butylcyanoacrylate monomer during nanoparticle formation was investigated. 5FU in acidic solution (pH 2-3) may interfere in the initiation process through its amino groups via the formation of zwitterions. The proposed zwitterionic mechanism of initiation was supported by the molecular weight profiles of the polymer, determined by gel permeation chromatography, and the covalent linkage of the cytostatic to the main polymer chain. H NMR analyses clearly demonstrated that a significant fraction of 5FU was covalently bonded to the poly(butylcyanoacrylate) chains through its amino groups preferentially through one of the two nitrogen atoms. In vitro release study performed shows that the investigated 5FU-loaded PBCN are suitable for sustaining delivery of 5FU.

Antimetabolites, Antineoplastic↗
PubMed2003

Poly(butylcyanoacrylate) nanoparticles for topical delivery of 5-fluorouracil.

Poly(butylcyanoacrylate) nanoparticles (PBCN) as a drug carrier of 5-fluorouracil (5FU) intended for topical treatment of skin lesia were investigated. The presence of 5FU (as saline solution, pH 10-11) in the polymerization medium affected the polymerization as well as the nanoparticle formation by influencing the initiation of the polymerization reaction. 5FU acted as an initiator in the anionic polymerization of n-butylcyanoacrylate monomer through its nucleophilic nitrogen centers. The results obtained by GPC, 1H NMR, and X-ray diffraction allude to a possible mechanism of cytostatic immobilization in the polymer matrix, with evidence for both free and bound forms of the drug.

Administration, Topical↗
PubMed1998

Various statistical methods in use for evaluating human malignant gastric specimens.

This paper presents the use of certain statistical methods (comparison of means - independent samples t-test, multiple linear regression analysis, multiple logistic regression analysis, analysis of clusters, etc.) included in the SPSS Statistical Package used to classify the patients quantitatively evaluated after a subtotal resection of their stomachs. The group consisted of 40 patients subdivided into two groups: primary neoplasia of the stomach (20 patients), and corresponding lymphogenic deposits in the abdominal perigastric lymph nodes (20 patients). Paraffin-embedded tissue sections (thickness 4-5 microm) prepared as consecutive hematoxylin-eosin-stained slides were morphometrically measured by a rotation of a graduated eyepiece-micrometer; thus, we obtained the minor and major axes' lengths of the elliptic nuclear profiles and the minor and major caliper diameters of the corresponding cellular profiles. These four variables were used to determine the dynamic changes in quantitative features of human gastric lesions when passing from normal histological structures, through hyperplastic processes (chronic gastritis), gastric precancer (ulcers and polyps with or without malignancy) till the development of primary carcinomas and their corresponding lymphogeneous metastases. Besides the increased cytomorphometrical measures, we also noted an opportunity to classify the patients according to these data as well as to add to the knowledge of our consultation system for clinical aid and use, recently published in the literature.

Humans↗
PubMed1998

DNA ploidy and morphometric features of normal, hyperplastic, premalignant and malignant specimens: an evaluation.

OBJECTIVE: To evaluate nuclear DNA assessments and morphometric variables on various breast cytologic smears and paraffin-embedded tissue sections of human breast and gastric lesions. STUDY DESIGN: Using the "plug or gore" method of Swift and Rasch for absorption cytophotometry with standard optical conditions on the Opton-MPM 01 cytophotometer as well as a graduated eyepiece micrometer on an Amplival microscope, cytologic smears from 33 women and tissue sections from 36 women with breast lesions and 150 patients with various gastric processes were quantitatively evaluated after measurement of nuclear DNA content amounts and morphometric variables. RESULTS: Normal-fitting distributions were found in the diploid-tetraploid regions of the cell cycle. Single cells possessed nuclear DNA content values in the hypodiploid region. Hyperplastic processes--i.e., fibrocystic disease and chronic atrophic (hypertrophic) gastritis--as well as benign tumors (breast fibroadenomas and gastric adenomas) showed abnormally high DNA content: aneuploidy with values in the pentaploid (5C) to octaploid and hyperoctaploid regions. Carcinomas with different origin had DNA values up to 10-16C. We also noted increasing morphometric data in the pathway from normality to cancer. CONCLUSION: Patients with hyperplastic processes who have abnormally high DNA content assessments with aneuploid cell populations and increased morphometric measures have to be very carefully and precisely evaluated. Moreover, these lesions are potentially malignant, with a high risk of cancer development in the future.

Breast↗
PubMed1997

Dynamic changes in quantitative features of human gastric lesions.

Quantitative DNA, morphometric cellular and nuclear variables were evaluated in surgical biopsies from patients with various gastric lesions: chronic gastritis, chronic ulcers, adenomatous polyps (gastric adenomas), primary carcinomas and their corresponding lymph-node metastases. Paraffin-embedded tissue sections were studied by static cytophotometry (plug method), karyometry (measurements with a graduated eyepiece micrometer of the major and minor axes of the elliptic nuclear profiles, and calculation of profile areas), and measurements of cellular profiles (largest and smallest caliper diameters). Tissue lymphocytes from the same slide were used as diploid controls for the DNA evaluations. An increase of both cellular and nuclear dimensions and DNA content was noted in all pathological tissues, as compared to normal mucosa; the highest values are found in primary gastric carcinomas. A progressive pattern increase of cellular and nuclear dimensions and of DNA content was observed through normal to cancerous tissues, chronic gastritis, chronic ulcers and adenomatous polyps (adenomas). Lymph-node metastases, in our study, had smaller nuclear (cellular) dimensions than primary cancers.

Adenocarcinoma↗
PubMed1997

Consultation system for diagnosis of gastric lesions.

OBJECTIVE: To present a knowledge-based classification system, GASTRO, for gastric lesion diagnosis. STUDY DESIGN: The study group consisted of 150 patients with various gastric lesions (25 relatively normal, 30 gastritic changed, 25 ulcerous, 25 adenomatous, 25 cancerous and 20 metastatic cases). After a subtotal gastrectomy, the lesions were routinely diagnosed and quantitatively evaluated. The control group consisted of 25 patients with relatively normal mucosae. Both quantitative methods were used for determining the dynamics of malignant processes of gastric mucosa. RESULTS: During the consultation more than 20 factors influencing disease dynamics were considered. Statistics on cellular and nuclear parameter changes in stomach mucosa were also used in the diagnosis of gastric lesions. CONCLUSION: Diagnoses were generated with confidence levels of 90%, 95%, and 99%. The final decision remained the responsibility of the physician.

Adenocarcinoma↗
PubMed1990

[Comparative histological and light-microscopic cytomorphometric studies of the tissue repair processes in postoperative wound complications treated locally with helium-neon laser radiation or a proteolytic enzyme].

Morphological studies were carried out on tissue material, removed from wound peripheral parts during application of secondary sutures on 69 complete perineal wound dehiscences of parturients prepared by helium-neon laser irradiation according to a method described by us, as of wound peripheral parts of 15 perineal wound dehiscences, prepared by alphahymotripsin dissolved in a solution with vitamin C. Histological preparations were stained by hematoxilin-eosin by van Gieson (for collagenous fibres), by Weigert (for elastic fibres) and by Gomori (for reticular fibres). Light microscopic cytomorphometric studies were made by a graduated ocular micrometer on stained with hematoxilin-eosin tissue sections with the help of standard optical system. The results of the performed histological examinations give foundation to accept the occurred more active stimulation of inflammatory and proliferative phase of wound reparative process after laser therapy with helium-neon laser irradiation. Light microscopic cytomorphometric studies indicate the presence of more advanced in its development granulation tissue after laser therapy by means of activation of local immunocompetent cells.

Chymotrypsin↗
PubMed1990

[An evaluation of endogenous lectins in the intrapulmonary metastases of osteogenic sarcoma].

Assessment is made of the presence or absence of specific sugar receptors (lectins) in patients operated for intrapulmonary metastases of osteogenic sarcoma. Investigations were carried out on histochemically stained paraffin sections for the separate types of sugars. Highest was the presence of specific receptors for sialic acid and for N-acetylglucosamine, followed by those for ramnose and heparin and least for mannose and maltose. Lectin determination is a new branch in morphological science, assisting clinical practice, special surgical activity by the attempt for quantitative grading of cell populations in norm and in their neoplastic development.

Female↗
PubMed1989

[Histologic and light-microscopic cytomorphometric studies of the tissue reparative processes in complete wound dehiscence after obstetrico-gynecologic surgery].

The authors carried out comparative histological and light microscopic cytomorphometric studies on tissue material, obtained during fixation of secondary sutures on complete wound dehiscences after obstetric and gynecological operations, prepared for therapy only by helium-neon laser irradiation. Densities of the power of helium-neon laser irradiation 90,70 an and 50 mW/cm2 were investigated at exposition time of the field of 1.5 min. The number of irradiations was 7-9 (after applied density of the power of 90, and 70 mW/cm2) and 9-12 (after irradiation with densities of the power of 50 mW/cm2). Histological and light microscopic cytomorphometric studies showed that the applied density of the power of laser irradiation of 90 mW/cm2 stimulated most actively the processes of tissue repair in complicated operative wounds. A considerable slowing of the processes of tissue repair was established after irradiation with densities of the power of 50 mW/cm2.

Combined Modality Therapy↗
PubMed1989

Quantitative cytomorphological evaluations of digestive tract ulcer malignization.

By means of a graduated eyepiece micrometer, cytomorphometric measurements were made on consecutive slides from an autopsy case with a malignized duodenal ulcer. Quantitative data were similar on average to gastric malignized chronic ulcers, and differed considerable (twice less) from primary gastric carcinomas with unknown origins and their corresponding lymph-node metastases.

Duodenal Neoplasms↗
PubMed1989

Children mesenchymal tumours in cytomorphometric assessments.

This paper offers the quantitative morphological data (light-optical morphometry with the aid of a graduated eyepiece micrometer) of some mesenchymal children tumours. 3 cases of neurofibrosarcoma with various degrees of differentiation were morphometrically expressed, compared with morphometric epithelial tumour data. The differences between both tissues, which existed after routine histomorphological studies, were also quantitatively confirmed (3 times smaller morphometric parameters for neurofibrosarcomas). These measurements were used as initial attempts at quantitative evaluation expansion in pathology.

Child↗
PubMed1986

Glomerulometric data in experimental toxicological investigations.

Glomerulometric quantitative investigations from rat kidney during chronic attempt with the substances Deta-20 and Polystabil VZ on paraffin sections were carried out. These substances are utilized in textile and food industry. Data, obtained by means of a graduated eyepiece-micrometer for light microscope, were plotted on histograms. This work is an attempt to introduce lightoptical morphometric measurements for nuclei and cells as well as for other structures (glomeruli).

Animals↗