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Biomedical subjects

G Dimitrov

Publications and source records attributed to G Dimitrov.

At least 19 recordsLinked to original sources
PubMed2003

[A new approach for discovering minimal residual disease in patients with operable breast cancer].

The striving of surgeon for achieving better long-term results of surgical treatment of patients with breast cancer put the searching of new independent prognostic factors for the exit of the treatment. This has become possible in the last decade of XX century when new diagnostic methods as immunochistochemistry, polimerase chain reaction (PCR), cytomorphology etc. entered the clinical practice. With bone marrow biopsy in patients with breast cancer earlier diagnosis of minimal residual disease is achieved, the approach to those patients is changed and a possibility for discovering women at higher risk is given. By immunochistochemistry method in the diagnostics of minimal residual disease in patients with breast cancer, more precise staging is achieved. This will change the therapeutic approach to these patients.

Biopsy↗
PubMed2002

Variability in the taxonomic characters of Black Sea gyrodactylids (Monogenea).

Variability of the haptoral hard parts of four Black Sea Gyrodactylus species (G. alviga Dmitrieva & Gerasev, 2000; G. crenilabri Zaika, 1966; G. flesi Malmberg, 1957; G. sphinx Dmitrieva & Gerasev, 2000) was studied in relation to season, host and geographical variability. A discriminant analysis was carried out on the measurements of 14 characters of the haptor of all four species. The haptoral hard parts of the investigated gyrodactylids decrease in size with an increase in water temperature. It is known that life-span of gyrodactylids is negatively correlated with water temperature and they exhibit peak intensities at low temperature. At the same time, life-span is considered to be a general indicator of a favourable environment. Therefore, high water temperature is not apparently advantageous for gyrodactylids. In the case of low marine salinity, in adapted species the sizes of the haptoral hard parts are larger at lower levels of salinity and vice versa for typical marine species. Lastly, in specimens parasitising the primary host, these features are larger than in those parasitising a secondary host. It is possible to say that, in general, the more favourable the environment for gyrodactylids the larger their haptoral hard parts. Unfavourable environmental conditions reduce the time of embryogenesis, which has a dual effect on gyrodactylids: positive in relation to their reproduction (by increasing the reproduction rate) and negative in relation to their development (by decreasing the size of the haptoral hard parts).

Animals↗
PubMed2001

Evaluation of oxidative stress in patients with cancer.

The oxidative stress is considered to be involved in the pathophysiology of cancers. In the current study we explored the oxidative stress in patients with different cancers and corresponding benign diseases by evaluation of the level of lipid peroxidation products (MDA level) in the plasma and the activity of erythrocyte antioxidant defense enzymes superoxide dismutase (SOD) and catalase (CAT). Significantly higher plasma levels of lipid peroxidation products were detected in patients with early and advanced cancers in comparison to the healthy volunteers (mean 3.1 micromol/l and 2.3 micromol/l, p = 0.0003 and p = 0.029, respectively, t-test). In addition, 10-20 days after radical operations of cancer patients with normal postoperative recovery period, the plasma levels of MDA decreased and reached values close to the controls (mean 2.0 micromol/l). SOD in erythrocytes of patients with benign diseases and malignant solid tumors before and after surgery did not differ from that of the controls. In contrast, CAT activity of patients with early cancers was found to be significant higher than that of the controls (mean 22157.2 U/gHb vs. 12832.0 U/gHb, p = 0.032, t-test). A decrease of CAT activity was observed after surgery (mean 15225.0 U/gHb). In conclusion, our results suggest the presence of an increased oxidative stress accompanied by a lack of changes of erythrocyte SOD activity and an adaptive increase of CAT activity.

Adult↗
PubMed2001

Mouse BAC ends quality assessment and sequence analyses.

A large-scale BAC end-sequencing project at The Institute for Genomic Research (TIGR) has generated one of the most extensive sets of sequence markers for the mouse genome to date. With a sequencing success rate of >80%, an average read length of 485 bp, and ABI3700 capillary sequencers, we have generated 449,234 nonredundant mouse BAC end sequences (mBESs) with 218 Mb total from 257,318 clones from libraries RPCI-23 and RPCI-24, representing 15x clone coverage, 7% sequence coverage, and a marker every 7 kb across the genome. A total of 191,916 BACs have sequences from both ends providing 12x genome coverage. The average Q20 length is 406 bp and 84% of the bases have phred quality scores > or = 20. RPCI-24 mBESs have more Q20 bases and longer reads on average than RPCI-23 sequences. ABI3700 sequencers and the sample tracking system ensure that > 95% of mBESs are associated with the right clone identifiers. We have found that a significant fraction of mBESs contains L1 repeats and approximately 48% of the clones have both ends with > or = 100 bp contiguous unique Q20 bases. About 3% mBESs match ESTs and > 70% of matches were conserved between the mouse and the human or the rat. Approximately 0.1% mBESs contain STSs. About 0.2% mBESs match human finished sequences and > 70% of these sequences have EST hits. The analyses indicate that our high-quality mouse BAC end sequences will be a valuable resource to the community.

Animals↗
PubMed2000

The discrimination of abrupt changes in speed and direction of visual motion.

A random dot pattern that moved within an invisible aperture was used to present two motions contiguously in time. The motions differed slightly either in speed (Experiments 1 and 3) or in direction (Experiments 2 and 4) and the subject had to discriminate the sign of the change (e.g. increment or decrement). The same discrimination task was performed when the two motions were temporally separated by 1 s. In Experiments 1 and 2 discrimination thresholds were measured with motion durations of 0.125, 0.25, 0.5 and 1.0 s and mean speeds of 2, 4, 8, and 16 degrees/s. In Experiments 3 and 4 thresholds were measured with aperture widths of 5 and 20 cm. The discrimination of contiguous motions progressively deteriorated with decreasing duration and mean speed of motion. For the lowest value of duration the Weber fraction for contiguous speeds was more than three times as the Weber fractions for separate speeds. For the same low value of duration the thresholds for discrimination of direction of contiguous motions were only about 50% higher than the thresholds for separate motions. The Weber fraction for contiguous speeds was ca. three times higher with the smaller aperture than with the larger one, provided the ratio 'aperture width mean speed' (i.e. the lifetime of the moving dots) was less than 0.3 s. Aperture width did not affect the discrimination of direction of contiguous motions. The discrimination of contiguous motions is discussed together with the known data for detection of changes in speed and direction. It is suggested that both, detection of changes in speed and discrimination of the sign of speed changes, may be performed by a common visual mechanism.

Adult↗
PubMed2000

[Genetic changes in breast cancer - an overview].

Current understandings about development of breast cancer from genetic point of view are discussed. Information about the hereditary forms of cancer is presented. Different forms of screening and problems connected with their application are discussed.

BRCA1 Protein↗
PubMed2000

[Radioimmunoguided surgery - a new stage of therapeutic management of oncological patients].

Thanks to the fast development of nuclear medicine and radiodiagnostics with highly informative techniques it became possible to use the application methods the surgical practice. The methods that are used the nowadays intraoperative techniques aim to help the malignant disease, to stage more precisely the process; to help visualisation of the metastases and to evaluate the volume of the used surgical techniques that highly informative. This is possible through the last 1-2 years by application monoclonal antibodies labeled by radioisotopes, whose specific accumulation is evaluated by the help of gamma-tetector probe (GDP).

Humans↗
PubMed1997

[Breast cancer and pregnancy].

Breast carcinoma is a condition characterized by an ever increasing incidence. Young women too are ever more frequently involved. Currently a modern tendency is observed of young women to postpone conception for a later period of life on account of a number of socioeconomical reasons, which tendency tangibly augments the number of women affected with breast cancer during the pregnancy period. Most of the pregnant women are in the age group 34 to 35 years. Breast cancer during pregnancy is a malignant disease ranking second by incidence rate. The latter amounts to 10-30 per 100,000 of pregnant women.

Adult↗
PubMed1996

What determines the detection of changes in motion velocity? A comment on Dzhafarov, Sekuler, and Allik (1993)

We comment on a recent model aimed at explaining data on speed of reaction to motion onset and to changes in motion velocity. The model is based on calculating the running variance of the stimulus positions passed during the motion. We show that although the model is successful in explaining data on motion onset and suprathreshold velocity changes, it may not be able to explain data on time of reaction to changes in velocity when these are near the detection threshold.

Acceleration↗
PubMed1996

[Intraoperative abdominal echography].

Experience with and the impressions of adopting intraoperative abdominal echography in eighteen patients, aged 26 to 73 years, 9 men and 9 women, are shared. The distribution of patients by pattern of diseases is as follows: colorectal carcinoma--4 cases, liver echinococcus--one, gastric carcinoma--one, hepatocellular carcinoma--one, cholangitis acuta purulenta-one, echinococcus of lung and liver--one, calculous cholecystitis with choledocholithiasis--five, and carcinoma of ductus choledochus--one. Fifty intraoperative abdominal echographies and one intrathoracic supradiaphragmatic echography of the liver are performed. Intraoperative abdominal echography of tumors involving organs of the digestive tract contributes to specify the staging of the neoplastic process. In liver echinococcus it determines precisely the number of cysts and diagnoses impalpable cystic formations, while in choledocholithiasis it documents the presence of calculi in the biliary tracts and eventual dilatation of intrahepatic ones. In five patients intraoperative abdominal echographic is done in conjunction with intraoperative fiber choledochoscopy.

Abdomen↗
PubMed1995

Temporal thresholds and reaction time to changes in velocity of visual motion.

A random dot pattern moved at a velocity V1. The velocity then increased or decreased abruptly to another value V2 for some time and again returned to V1. The temporal threshold, i.e. the duration of V2 that was necessary to detect the change was measured. Thresholds for the detection of the same velocity increment, V2 = 2 x V1, were shorter when the baseline velocity V1 increased from 1 to 8 deg/sec (Expt 1). The temporal threshold decreased as the velocity contrast (V2 - V1)/(V1 + V2) increased from 0.33 to 0.77. The thresholds for the detection of velocity decrements were in general longer than those for the detection of increments (Expt 3). In Expts 2 and 4 the random-dot pattern moved with velocity V1, which abruptly increased or decreased to V2, without returning to V1. The reaction time to the change was measured for the same velocity pairs as those used in the temporal threshold measurements. There was a good correspondence between changes in the reaction times and changes in the thresholds under the various conditions. The data are interpreted on the basis of two hypotheses: higher velocities are detected by mechanisms that respond more rapidly; and integration of velocities occurs when temporally-adjacent motions are presented.

Adult↗
PubMed1995

Use of subcutaneous implantable infusion systems in neoplastic and AIDS patients requiring long-term venous access.

OBJECTIVE: To evaluate the life span and complication rates of totally implantable infusion devices in patients with short bowel syndrome and in immunocompromised patients with AIDS, lymphoma, and myeloma who required long-term central venous access. DESIGN: Prospective open study. SETTING: University hospital, Italy. SUBJECTS: Group I - 5 patients with short bowel syndrome; group II - 11 patients with AIDS; and group III - 15 patients with lymphoma or multiple myeloma (1 of whom had 2 devices implanted). MAIN OUTCOME MEASURES: Duration of implantation and incidence of catheter-related complications. RESULTS: The mean duration/patient of the catheter was 422 days (range 20-1257) in group I; 104 days (range 43-262) in group II; and 415 days (range 62-1280) in group III. There were no catheter related complications in the patients in group I (short bowel syndrome). Of the 11 patients with AIDS (group II) 4 developed catheter related infections (0.32/100 catheter days), and 1 developed a thrombotic occlusion. All 5 catheters were removed (3 for infection). Of the 15 patients with lymphoma or myeloma who had 16 catheters implanted (group III), 1 patient developed 3 infective episodes (0.05/100 catheter days), 1 catheter migrated and 1 occluded. All 3 catheters were removed. CONCLUSION: Totally implantable infusion systems can safely be used for prolonged periods in immunocompromised patients, including those with AIDS if their life expectancy is reasonable.

Acquired Immunodeficiency Syndrome↗