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Biomedical subjects

G Todorov

Publications and source records attributed to G Todorov.

At least 19 recordsLinked to original sources
PubMed1997

[Retroperitoneal laparoscopic adrenalectomy. The 3-trocar surgical technic].

Laparoscopic adrenalectomy (LA), introduced in surgical practice quite recently, proves to be an effective method for treating diseases of the adrenal gland on account of the good visualization provided, in conjunction with all additional advantages of laparoscopic surgery, such as reduced traumatism, postoperative pain alleviation, shortened hospital stay and the like. Two patients presenting Cushing's syndrome are subjected to retroperitoneal laparoscopic adrenalectomy (RLA). With the patient in lumbotomy position on the operating table, a retroperitoneal space is created using a balloon dissector (Ethicon). The optics is introduced after placing a 10 mm balloon trocar (Origin). Under visual control two additional 10 mm trocars are placed along the course of lumbotomy line, accordingly along the anterior and posterior axillary lines. Next blunt dissection of the adrenal gland is done, and a clip applied to v. centralis. The adrenal gland is removed through one of the trocars, and the operation terminates after hemostasis and insertion of a drainage tube. The patients are discharged on the 4th postoperative day in a good general condition, mobilized, well fed with restored passage. In conclusion, the assumption is warranted that the early experience with RLA is encouraging as a safe and considerably less traumatic surgical procedure for operative management of diseases of the adrenal glands.

Adrenalectomy↗
PubMed1997

[The surgical treatment of cervical lymph node metastases in differentiated thyroid carcinoma].

Over the period 1980 through 1994, a total of 297 patients presenting histological evidence of differentiated carcinoma of the thyroid gland are studied. In thirty-two of them (10.8 per cent) palpable metastases in the lymph nodes are found at the time of making the diagnosis. A higher frequency of palpable lymph nodes is established in younger patients with histological diagnosis papillary carcinoma (62.5 per cent). In the 32 patients with palpable metastases in the lymph nodes, discovered during diagnosing of the disease, lymph node dissection is undertaken. The obtained results show that the modified cervical dissection yields favourable results, and at the same time preserves intact the neck structure.

Adenocarcinoma, Follicular↗
PubMed1995

Activity of RNA polymerase I transcription factor UBF blocked by Rb gene product.

The protein encoded by the retinoblastoma susceptibility gene (Rb) functions as a tumour suppressor and negative growth regulator. As actively growing cells require the ongoing synthesis of ribosomal RNA, we considered that Rb might interact with the ribosomal DNA transcription apparatus. Here we report that (1) there is an accumulation of Rb protein in the nucleoli of differentiated U937 cells which correlates with inhibition of rDNA transcription; (2) addition of Rb to an in vitro transcription system inhibits transcription by RNA polymerase I; (3) this inhibition requires a functional Rb pocket; and (4) Rb specifically inhibits the activity of the RNA polymerase I transcription factor UBF (upstream binding factor) in vitro. This last observation was confirmed by affinity chromatography and immunoprecipitation, which demonstrated an interaction between Rb and UBF. These results indicate that there is an additional mechanism by which Rb suppresses cell growth, namely that Rb directly represses transcription of the rRNA genes.

Amino Acid Sequence↗
PubMed1995

[Differentiated thyroid cancer--a study of the pathomorphological variants in 216 patients].

Two-hundred sixteen patients presenting differentiated carcinoma of the thyroid gland are subjected to operative treatment over the period 1980 through 1993. The distribution of cases by histological type is as follows: papillary carcinoma--127 cases, follicular--58, and mixed type (papillary-follicular)--thirty one. In the group presenting papillary lesions, infiltration of the capsula is noted in nine cases, multifocal location--in five, and microcarcinoma--in twenty three. In the follicular carcinoma group a markedly expressed vascular invasion is established in four cases, multifocal location--three, and microcarcinoma--five. Assessment of the morphological patterns of differentiated thyroid carcinoma reveals a marked predomination of noncomplicated histologic variants, enabling the wide use of minor conservative operative procedures, compared to thyroidectomy, with a positive outcome. Over he past few decades, the incidence of differentiated forms of thyroid gland carcinoma shows an increase, and nowadays it caries in the range 60 to 90 per cent. Papillary forms are prevailing, while follicular carcinomas are detected in 8 to 20 per cent of cases. An overall shift of morbidity towards younger ages and female gender is observed.

Adenocarcinoma, Follicular↗
PubMed1995

[Hypophyseal-thyroid function following partial thyroid resections for euthyroid struma nodosa].

The serum levels of svT3, svT4, TTH, T3 and T4 are evaluated at two, six and twelve months after partial resection of the thyroid gland in patients with euthyroid struma nodosa. The patients are divided up in two groups: group one--given hormonal substitution therapy, and group two--untreated. The results are estimated with a special reference to the need of hormonal administration in view of precluding recurrences.

Adolescent↗
PubMed1995

[The incidence and morphological aspects of thyroid cancer].

A total of 10,736 biopsy specimens presenting diverse thyroid gland pathology are studied over the period 1974 to December 1993. The histopathological investigation shows that 5.45 per cent of them (n = 585) are with carcinoma. Comparative analysis of the incidence of thyroid carcinoma in the series reviewed, covering the two decades, points to a tendency of the incidence rate to augment from 4.03 per cent in the first decade to average 6.63 per cent in the second decade of study, with a frequency peak reached in the period 1986-1993. There is a clearcut tendency of the incidence of malignant conditions of the thyroid to rise among younger age groups. A markedly expressed tendency of the number of patients with papillary carcinoma of the thyroid, affecting mainly women and younger persons, to increase is also documented.

Adult↗
PubMed1995

[The routine immunohistochemical diagnosis and surgical treatment of medullary carcinoma of the thyroid].

Over the period 1977 through 1988, in the Research Institute of Surgery--Medical Academy a total of 372 patients undergo primary operative management for thyroid gland carcinoma. Medullary carcinoma is discovered in 18 patients of the series (4.8 per cent). The preoperative diagnosis is supplemented by thyroscintigraphy with 131iodine or technetium Tc 201. After 1981, calcitonin and carcinoembryonic antigen (CEA), specific medullary thyroid carcinoma (MTC) markers, measurements are routinely done, with substantially elevated levels in the patients under study being found, in those with metastases inclusive. Presumably, the preoperative diagnosis medullary thyroid carcinoma is very difficult, and only a combined approach, including thyroidectomy with ensuing iodine radiotherapy, may account for a good survivorship. Postoperatively, all patients with MTC diagnosis are regularly tested for serum calcitonin and CEA levels. The carefully taken family history and questioning of the patients allows to differentiate familial from cases from sporadic neoplasms.

Adult↗
PubMed1995

[Early thymectomy in the treatment of myasthenia gravis].

Over a 10-year period, 1983 through 1992, in the clinic of endocrinologic surgery--Alexander Hospital, Sofia, 89 patients with myasthenia gravis (MG), 57 women and 32 men, are subjected to operative treatment--thymectomy. The mean age in women is 32 years (range 19 to 68), and in men--45.6 years (range 25 to 70). Two age-related distributions in the series are impressive--in female patients the peak is between 20 and 30 years, whereas in men--between 45 and 55 years. The operative intervention consists in total thymectomy. Preference is given to the trans-sternal median access to the thymus gland. In the complex therapeutic approach to MG are included also a number of drugs and other agents--corticosteroids, anticholinesterase agents, immunosuppressives and the like. Patients undergoing operative thymectomy are usually given preoperative treatment with anticholinesterase drugs for different periods of time. Operation is undertaken only in stable condition of the patients. Good postoperative results are recorded in 57 per cent of those operated by the first year, with a satisfactory improvement in 29.2 per cent of them. In the third group (13.4 per cent) the postoperative results are poor, and treatment is proceeded with anticholinesterase drugs or immunosuppressives. The average follow-up term is 44.7 months. The delay in improvement is typical of patients with longer duration of the complaints, but it may be attained within 2, 3 or 5 years postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[The surgical treatment of myasthenia gravis--the authors' own experience].

Proceeding from personal experience accumulated hitherto, the indications for both operative treatment of MG, and choice of the most adequate preoperative preparation and timing of thymectomy, are precisely determined. Pathohistologic findings and postoperative results in 47 patients, thymectomized in the period 1989 to 1994, are followed up and analyzed. The inference is reached that preliminary stabilization of the patient's condition with anticholinesterase drugs, and early and total thymectomy are essential for the successful outcome of treatment. It is preferable that thymectomy is done within six months of the occurrence of complaints or making the diagnosis.

Adult↗
PubMed1995

[Struma nodosa and cancer of the thyroid].

The disputable issue of the pathogenetic relation between struma nodosa and thyroid gland carcinoma is discussed. A total of 234 patients with definitive diagnosis thyroid carcinoma, operated in the clinic of endocrine surgery--Higher Medical Institute, Sofia, are retrospectively analyzed. Clinical, past history and pathomorphologic data are considered--123 patients present papillary carcinoma, 67--follicular, and 42--mixed form. All patients undergo operative management over the period 1980 through 1991. Later, to the aforementioned group are added further 50 patients with carcinoma of the thyroid, treated from 1991 to late December 1992, and thus the total number amounts to 284 cases--153 papillary, 79 follicular and 52 mixed forms, respectively. In 67.2 per cent of the cases the thyroid carcinoma presents clinical patterns of a solitary node, in 27.8 per cent--node of multinodular struma, and in 4.9 per cent--formation associated with another thyroid disease. Multifocal location is established in five cases. As shown by the pathomorphological study in 18 per cent of the cases it is a matter of a combination--thyroid carcinoma and struma multinodosa, and in 1.2 per cent of the cases only there is conclusive evidence of solitary adenoma malignization. The obtained results lead to the inference that thyroid carcinoma deriving from the nodose structures of the gland is an exception, rather than rule.

Adenocarcinoma, Follicular↗
PubMed1993

Translocation of retinoblastoma protein associated with tumor cell growth inhibition.

Immunocytochemistry revealed an association between growth inhibition and a translocation of retinoblastoma protein (pRB) to the nucleoli of U-2 osteosarcoma cells inhibited in their growth by the negative growth factor NCPI (natural cell proliferation inhibitor). Similar phenomenon was demonstrated by Western blot analysis and immunocytochemistry in U937 leukemic cells inhibited in their growth and induced to differentiate by 12-O-tetradecanoylphorbol acetate (TPA). Total nuclear extract of control U937 cells gave an intense 110 KD band, while total nuclear extract of TPA treated cells produced an intense 60 KD band and a weak 110 KD band. No bands were observed for the purified nucleoli of control cells, but the purified nucleoli of TPA treated cells produced a 60 KD band. These results suggest that in the process of cell growth inhibition and differentiation, specific proteolysis of pRB and its translocation to the nucleolus may occur.

Blotting, Western↗
PubMed1993

[Changes in electrolyte excretion in the saliva of 8th-grade students of a music school in Sofia].

The present work is part of a complex study of the health problems concerning the training of schoolchildren from the musical school--Sofia in specialty violin and piano. In order to examine the changes in the activity of the sympathetic-adrenal system for tracing the concentrations of sodium, potassium and index sodium/potassium in saliva of schoolchildren from the musical school during the general education program and also during individual training. The changes established during the experiment show the dynamics in the functional state of the sympathetic-adrenal system. We have to mention, that during the individual training an increased activity of the adrenal is observed, in connection with the emotional adjustment and emotional expenditure of schoolchildren.

Bulgaria↗
PubMed1992

Increase in protein kinase C activity is associated with human fibroblast growth inhibition.

Protein kinase C (PKC) activity and DNA synthesis were measured in human fetal bone marrow fibroblasts following treatment with tumor necrosis factor alpha (TNF alpha) (500 U/ml) or conditioned media containing natural cell proliferation inhibitor (CM-NCPI). Treatment with TNF alpha led to growth stimulation (120 +/- 7% of control in 24 h, 141 +/- 6% in 72 h). At the same time particulate PKC activity diminished, reaching 55 +/- 8% of control in 24 h and remaining at this level at 72 h. CM-NCPI treatment of the cells resulted in a decrease in DNA synthesis (by 39 +/- 6% in 2 h, by 58 +/- 5% in 24 h, and by 78 +/- 8% in 72 h). This was accompanied by a significant rise in particulate PKC activity which increased over 3-fold in 2 h, over 5-fold in 24 h, and up to 11-fold in 72 h. This 11-fold elevation was maintained after 2 week exposure of the fibroblasts to CM-NCPI. The PKC inhibitor neomycin abolished CM-NCPI induced growth inhibition, whereas PKC activator 12-O-tetradecanoylphorbol 13-acetate intensified it. These results suggest that CM-NCPI acts as PKC activator and that negative growth regulation by extracellular agents may involve stimulation of PKC activity.

Bone Marrow↗
PubMed1992

Influence of cation binding on the electro-optically determined electric moments of purple membranes.

Analysis of the electro-optically determined permanent dipole moment and electric polarizability of purple membrane fragments reveals the complex nature of the membrane electric moments. The problem to distinguish between the contribution of the membrane structural charges (charged groups of the polypeptide chain and polar lipid headgroups), bound cations and the electric double layer structure deserves particular attention not only because of its importance for electro-optics but also in respect to the relation of the membrane surface electric properties to the membrane transport function. The removal of divalent cations (Ca2+ and Mg2+) bound to purple membrane in the native state induces a cation-free species of purple membrane (deionized--blue membrane) with drastically changed spectroscopic properties and function. The present paper summarizes our study on the electric moments of blue membrane and their changes during the blue to purple transition. We intended to provide an insight into the possible regulation of this reversible transition (purple-to-blue and blue-to-purple) through changes of the asymmetric charge distribution and the importance of the asymmetric interfacial charge distribution for the proton transfer in purple membranes. The changes in the electric moments (permanent and induced dipole moments) of purple membrane fragments upon di- and trivalent cations binding to cation-depleted purple membranes were studied by electric light scattering (rotational electrokinetics) in d.c. and a.c. electric fields, and by electric pulses with reversing polarity. The results show a recovery of the membrane charge asymmetry (permanent dipole moment) though not of the induced dipole moment.

Bacteriorhodopsins↗